workshop on supercritical fl uids and...
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workshop onsupercriticalfl uids and energy
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workshop onsupercriticalfl uids and energy
Dados Internacionais de Catalogação na Publicação (CIP) (Câmara Brasileira do Livro, SP, Brasil)
Workshop em fluídos supercríticos e energia / M. Angela A. Meireles e Erdogan Kiran. (organizadores). – Campinas, SP : Mercado de Letras, 2013. – (Mercado de Letras Temas)
ISBN 978-85-7591-301-7
1. Biocombustíveis 2. Energia – Fontes alternativas 3. Fluídos supercríticos I. Meireles, M. Angela A. II. Kiran, Erdogan III. Série.
13-12026 CDD-541.34Índices para catálogo sistemático:
1. Fluídos supercríticos e energia 541.34
Capa e Projeto Gráfico: Vande Rotta GomideLayout e Editoração: André S. Tavares da Silva
Revisão: Gabriela Lopes Adami
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1a ediçãodezembro/2013
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CONTENTS
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Committee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
OVERVIEW/PLENARy LECTURES ON ThE ROLE OF SUPERCRITICAL FLUIDS AND TEChNOLOGy (SCFs&T)
State of SCFs&T — Future Directions and Progress in Commercialization . . . . . . . . . . 19
SCFs&T for Bio-based Fuel processes . . . . . . . . . . . 39
SCFs&T for New Materials and Materials Processing . . . . . . . . . . . . . . . . . . 49
SCFs&T for Green Chemistry and Sustainable Technology . . . . . . . . . . . . . . . 69
SCFs as Working Fluids and Process Technology . . . 83
PANEL PRESENTATIONSPanel I: Bio-based fuel processes . . . . . . . . . . . . . . 103
Panel II: New Materials and Materials Processing . . . . . . . . . . . . . . . . . 129
Panel III: Green Chemistry and Sustainable Technology . . . . . . . . . . . . . . 159
Panel IV: SCFs as Working Fluids / Process Technology and Design . . . . . . . . . . . . . . . . . . 187
Panel V: Process Technology and Future Direction . . . . . . . . . . . . . . . . . . . . 215
POSTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387
7
PREFACE
It is with pleasure that we present this book of abstracts
of the lectures and posters that will be presented at the
Workshop on Supercritical Fluids and Energy.
The idea of organizing a workshop on supercritical
fluids with a focus on energy emerged during the course
of casual exchanges between the co-directors of this work-
shop who shared the same dinner table at the Gala Dinner
at the 10th International Symposium on Supercritical Flu-
ids held in San Francisco in May 2012. The discussions
had initially started with commentaries on the ongoing
symposium and on the current status and future directions
of the supercritical fluid science and technology. One of
the questions that immediately surfaced was “how come
no industrial plants that employ supercritical fluids had
been built in Brazil or in South America despite decades
of ongoing active research by many in the region?” The
discussion quickly expanded and the questions became
broader. Brazil having played such an important role in
bio-ethanol production, and there being an ever increasing
interest in alternative fuels around the world, we ques-
tioned how new opportunities could be developed for the
supercritical fluid-based technologies to make an impact
in Brazil and elsewhere. What were the limitations? Where
were the bottlenecks? What was missing on fundamental
data? Were there misconceptions, if any, that needed to
be overcome to raise the level of interest for industrial
implementation? Were there a critical mass of trained en-
8 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
gineers who could take charge of such facilities and run
them safely if they were to be built? Furthermore, since
supercritical fluid research could impact “energy” use or
savings in many other ways than just developing new ap-
proaches to generate alternative fuels, additional questions
were raised on the impact of using supercritical fluids as
working fluids in power cycles; the energy saving potential
in materials processing, or forming new materials ranging
from particles, to fibers, to foams and aerogels with super-
critical fluids. It immediately became clear that addressing
these questions would greatly benefit our greater commu-
nity.
When viewed under such a broad umbrella, the ap-
peal of a Workshop, rather than a traditional conference
or symposia became extremely high as it would then be
attractive to colleagues with different backgrounds; with
everyone easily contributing by sharing their perspectives
of what is known, what is needed, and where the future
trends in the field lie from their own strength areas, while
gaining new perspectives in others. With this background,
we started to seek funding for the Workshop. The goal was
to generate sufficient funds to facilitate participation not
only by experts but also by young scientists. The Journal
of Supercritical Fluids made an early commitment to sup-
port the idea as the timing of the workshop would nicely
coincide with and mark the 25th anniversary of the Journal
being in publication. LASEFI was also immediately on
board. One of us (E. Kiran) discussed the idea with the
program managers for “Environmental Sustainability” and
“Energy and Sustainability” at the National Science Foun-
dation at the 2012 AIChE Annual Meeting in Pittsburg in
November 2012, and then submitted a proposal to NSF
which was funded. Simultaneously, a similar project was
submitted (by M.A.A. Meireles) to CNPq (Conselho Nacio-
PREFACE 9
nal de Desenvolvimento Científico e Tecnológico/ Nation-
al Council for Scientific and Technological Development)
in Brazil which was also funded.
With a sound base-funding secured from NSF,
LASEFI, CNPq and the Journal of Supercritical Fluids, the
workshop was formally announced at the 3rd Iberoamer-
ican Conference on Supercritical Fluids that was held in
Cartagena, Colombia in April 2013.
Our initial plans were to organize a modest work-
shop with a total of about 50-60 participants consisting of
25-30 experts and 25-35 postdoctoral fellows or senior grad-
uate students. However, the interest in the workshop far
exceeded our initial expectations. We are extremely pleased
that we have a total of 104 participants from 20 different
countries.
The first day of the technical sessions of the work-
shop is devoted to a total of 21 overview/plenary lectures
that are grouped under
1. State of the supercritical fluid science and technol-
ogy — future direction and status of commercial-
ization,
2. Supercritical fluid science and technology for bio-
based fuel processes,
3. Supercritical fluid science and technology for new
materials and materials processing,
4. Supercritical fluid science and technology for green
chemistry and sustainable technology and
5. Supercritical fluids as working fluids and process
technology.
The second day of technical sessions is devoted to
37 lectures on the role of supercritical fluid science and
10 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
technology that will be presented and discussed in five
parallel-run Panel sessions grouped under:
1. Bio-base fuel processes
2. New materials and materials processing
3. Green chemistry and sustainable technology
4. Supercritical fluids as working fluids / process tech-
nology and design
5. Process technology and future directions.
Also scheduled for the second day of the workshop
is the afternoon Poster Session that will have 42 presen-
tations by junior faculty members, postdoctoral fellows,
research associates, or senior graduate students.
The third day of the workshop is devoted to the
presentations and the discussions of the panel outcomes
by all participants.
This book of abstracts includes all the abstracts of
the overview and the panel lectures and the poster pre-
sentations which we trust you will find of value as a future
reference.
We would like to take this opportunity to thank all
the participants for their willingness to come to this work-
shop and share their knowledge, and their commitment
to the advancement of our field. We are optimistic that
this workshop will lead to new interactions and collabo-
rations, and in particular will help the next generation of
scientists to be connected with our greater community.
We are grateful to our international and local organizing
committee members, Drs. Gerd Brunner, Richard Smith,
Flávio C. Albuquerque, Sandra R. S. Ferreira, Camila G.
Pereira, Hosiberto B. Sant’Ana and Diego T. Santos for their
valuable insight in organization and help with the logistics.
PREFACE 11
We would also like to thank the various government
and private organizations which have provided additional
financial support to make this workshop possible. Our spe-
cial thanks go to Drs. Bruce Hamilton and Ram Gupta of
the National Science Foundation, CNPq, CAPES-PROEX,
Dr. Angela Welch of Elsevier and the Journal of Supercrit-
ical Fluids, Dr. J. W. King of the Supercritical Fluid Sym-
posia, Dr. Jacques Fages of the International Society for
Advancement of Supercritical Fluids, Volkmar Steinhagen
of UHDE, Chris Spilsbury of the BG Group, and Kenneth
R. Krewson of Supercritical Fluid Technologies.
M. Angela A. MeirelesErdogan Kiran
Workshop Directors
13
PRESENTATION
Supercritical fluids are a unique class of process fluids
and solvents, which display tunable properties. They are
employed at conditions beyond the thermodynamic vapor-
liquid critical point. At those conditions, properties of su-
percritical fluids can be changed over a wide range, and
adapted to process needs. They are attractive process fluids
in combining a set of unique properties like low viscosity,
high diffusivity, zero surface tension, and a high compress-
ibility. Water, for example, is used extensively as working
fluid in power generation processes, at conditions below
the critical point and increasingly at supercritical condi-
tions. Carbon dioxide and ammonia are utilized in a similar
way.
Supercritical fluids modify the properties of com-
pounds in mixtures. They dissolve components far beyond
their vapor pressure. They dissolve in other fluids and solids,
reducing their viscosity and surface tension substantially.
In chemical reactions, supercritical fluids act as non- reac-
tive process fluid or take part in the reaction, as is the case
with water in hydrolysis of biomass components or in ox-
idative waste destruction. In materials processing, super-
critical fluids become effective in modulating miscibility
and phase separation conditions leading to formation of
materials with a range of different morphologies.
The practical application of supercritical fluids re-
quires understanding of the fundamentals of multiphase
equilibria at high pressures and ultimately the design of
14 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
technical components and plants for production. Compared
to other technical systems, supercritical fluid production
plants are relatively simple, but the underlying principles
are complex and must be thoroughly investigated and
transferred to the users.
Significant advances have been made over the past
three decades in understanding the interaction of super-
critical fluids with natural and synthetic materials for phys-
ical and chemical transformations with beneficial results
that offer new and alternative pathways to materials pro-
cessing. Advances have also been made in the engineering
of processes, which employ supercritical fluids as process
media. One area of special importance that has emerged
is “Energy” in terms of the (a) use of supercritical fluids
in power generation or refrigeration; (b) use of supercriti-
cal fluids in biomass conversions for biofuel generations;
(c) use of supercritical fluids in reducing the environmen-
tal footprint of conventional processes; (d) use of supercrit-
ical fluids in generating new materials that have improved
thermal insulation properties; or (e) use of supercritical
fluids or supercritical-fluid based materials in improved
separation or property upgrading operations.
A current bottleneck is in overcoming some of the
misconceptions pertaining to overall costs and economics
of the potential processes in transforming the technology
base to large-scale implantations. It is with this background
that the proposed workshop is being organized.
The workshop will be held in Brazil, which is lead-
ing in its activity in bio-based alternative fuels and as such
is a natural location to address the central topic of Energy.
Brazil is also a location where intense activity is taking
place in bio-based material processing and will provide a
platform to look at the limitations in going from bench top
research to industrial implementation.
15
GOALS
The primary objective of this workshop is to create an
opportunity to (a) critically review the state of supercritical
fluid science and technology and its impact in various
facets of energy generation or energy savings and reveal
new perspectives for the improvement of energy related
processes, (b) assess the bottlenecks that are preventing
industrial scale implementation, (c) develop recommenda-
tions to facilitate transformation of lab scale findings to
large scale operations, and in so doing (d) identify future
research needs and mechanisms to rejuvenate and strength-
en interest and continuing support from federal agencies
for fundamental research to promote further developments.
The SFE’13 also intends to engage up and coming
new leaders in supercritical fluid science and technology
by bringing them to this workshop, and having them ful-
ly integrated into the broader network and give them a
stronger base to move forward. In 1993 and 1998 two NATO
Advanced Study Institutes had been organized each of
which had brought together about 25 lecturers and 75
young scientists. Those young scientists have themselves
now become leading names around the world with very
effective networking. It is anticipated that this workshop
will have a similar impact. Even though smaller in scale,
the workshop will be addressing an extremely significant
focus area and we believe will have a major impact.
We anticipate that the workshop will form a nucleus
for new collaborative efforts and possible multi-national
research initiatives.
17
COMMITTEE
WORKShOP DIRECTORS
M. Angela A. Meireles, University of Campinas, Brazil – Founder of Laboratory of Supercritical Technology: Extraction, Fractionation, and Identifi cation of vegetable extracts (LASEFI); [email protected]
Erdogan Kiran, Virginia Polytechnic Institute and State University, USA
– Founder and Editor-in-Chief of the Journal of Supercritical Fluids; [email protected]
INTERNATIONAL SCIENTIFIC COMMITTEE
Gerd Brunner, Hamburg University of Technology, Germany – Regional Editor (Europe) of the Journal of Supercritical Fluids
M. Angela A. Meireles, University of Campinas, Brazil
Erdogan Kiran, Virginia Polytechnic Institute and State University, USA
Richard Smith Jr., Tohoku University, Japan – Regional Editor (Asia) of the Journal of Supercritical Fluids
LOCAL ORGANIzING COMMITTEE
Flávio C. Albuquerque, PETROBRAS Research & Development Center,
Brazil
Sandra R. S. Ferreira, Federal University of Santa Catarina, Brazil
Camila G. Pereira, Federal University of Rio Grande do Norte, Brazil
Hosiberto B. Sant’Ana, Federal University of Ceara, Brazil
Diego T. Santos, University of Campinas, Brazil
OVERVIEW/PLENARy LECTURES ON ThE ROLE OF SUPERCRITICAL FLUIDS AND TEChNOLOGy (SCFs&T)
State of SCFs&T — Future Directions and Progress in Commercialization
PROCESS TEChNOLOGy AND FUTURE DIRECTIONS
21
PROCESS TEChNOLOGy AND FUTURE DIRECTIONS
gerd BrunnerHamburg University of Technology;
Eissendorfer Str. 38, D-21073, Hamburg, Germany; E-mail: [email protected]
what is “Process Technology”?
Process technology comprises the application of
fundamentals to processes, as for example phase equilib-
ria and reaction kinetics, the verification of process steps,
as for example in specific reactors, and the design of pro-
cess sequences to produce a product (energy!) from raw
materials.
For the special field of Supercritical Fluids related
to energy processes this general definition also applies.
Self-evident as this is, it includes single process steps as
well as process step sequences and whole processes. Also,
process technology is not restricted to any specific appli-
cation. It includes processing of renewable (bio-based)
materials, fossil materials, and processes to access these
materials.
In general, process technology related to the appli-
cation of supercritical fluids is based on the exploitation
of the specific properties of supercritical fluids. Again,
self-evident as it is, it includes the varying properties of
supercritical fluids itself and hence the tunability of the
working fluid and the interactions of supercritical fluids
with the processes materials. Mostly we have in mind in
this context the change of properties by dissolved super-
critical fluids, for example a drastically reduced viscosity.
22 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
Furthermore, supercritical fluids guarantee an enclosed
processing with emanations that can be adjusted. Super-
critical fluid processing of most materials results in a re-
duced amount of gas production. That gas can still be used
to fuel the process. In addition, supercritical fluids can
lead to improved yields, as I will show in an example for
oil shale exploitation, and in improved quality of the prod-
ucts.
Supercritical fluids have been used in quite a num-
ber of processes and process steps related to production
of energy, mostly in laboratory and demonstration scale.
Among these processes are: The ROSE process, coal liq-
uefaction and gasification, the production of oil from oil
shales, and of oil from oil sands.
Supercritical fluids have been proposed (and par-
tially are used) for: enhanced oil recovery, emulsion split-
ting (oil-water), enhanced gas recovery, bitumen separation,
recovery of hydrocarbons from particles (remediation of
soil), de-asphalting, removal of fine particles, and others.
Supercritical fluids are proposed for deep drilling (spall-
ation drilling), and for the production of energy from hy-
drothermal flames.
Process technology has to provide the equipment
for the processes. In general, there is no principal differ-
ence for bio-based materials and non-bio-based materials.
Design according to the process fundamentals has to be
provided for: reactors, heat transfer equipment, heat re-
covery systems, and systems for delivery and recovery of
solids. In addition, the question of corrosion has to be an-
swered.
Future directions can be seen in the provision of
fundamentals: for oil/water/SCF-processes, for oil/water/
SCF/particles-processes, for the design of small scale in-
stallations (economy, standardization), and for the design
STATE OF SCFs&T | FUTURE DIRECTIONS AND PROGRESS IN COMMERCIALIzATION 23
of proper technology for feeding and removal of solids.
Keys to future success will be: simple design, simple op-
eration, high efficiency (higher than burning the feed),
and a thorough training of the community in the specific
abilities of supercritical fluids.
ChALLENGES AND OPPORTUNITIES USING SUPERCRITICAL CO2: FROM FUNDAMENTALS TO INDUSTRIAL APPLICATIONS
25
ChALLENGES AND OPPORTUNITIES USING SUPERCRITICAL CO2: FROM FUNDAMENTALS TO INDUSTRIAL APPLICATIONS
Lourdes f. vegaMATGAS Research Center / AIr Products Group;
MATGAS Building – Campus UAB, 08193, Bellaterra, Barcelona, Spain; E-mail: [email protected]
As defined by the Brundtland Commission, sustainable
development is the development that “meets the needs of
the present without compromising the ability of future
generations to meet their own needs”. Sustainable devel-
opment is of special relevance in the present situation, in
which an explosive growth in energy consumption as a
consequence of the great inventions and developments
related to transportation, computers and technology is
observed, along with a rapid increase in population world-
wide. In this context, a great effort has been devoted in
recent years to develop sustainable processes or improving
existing ones, searching for a net positive impact in the
environment.
Carbon dioxide (CO2) is finding more and more uses
in industry today, from food and water treatment to ener-
gy and materials, replacing in some cases other com-
pounds with more impact into the environment. Among
these applications, supercritical carbon dioxide (scCO2) is
used as an alternative attractive solvent, replacing tradi-
tional ones, including hazardous chemicals and precious
water resources. scCO2 offers several advantages versus
other solvents: it can be easily recycled, it leaves no resi-
dues behind after processing and it is non-flammable,
non-toxic and inexpensive. The low process temperature
26 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
(31 ºC) allows for gentle processing, while the low surface
tension of scCO2 and its high diffusivity allows for excep-
tionally effective penetration. Increased environmental
awareness had led to restrictions on some traditional sol-
vents which are now recognized as toxic. Only a few sus-
tainable solvents remain available for future use. Hence,
as the society and industry continue to demand more ef-
ficient and greener processes, CO2 remains an attractive
alternative.
There are three key issues driving CO2 applications
from labs to industry: the increased fundamental knowl-
edge of CO2 and its interaction with the materials and
other compounds, used to find the best process and oper-
ating conditions, the optimization of process equipment
to handle the demands of operation at an industrial scale,
and the need to use environmentally benign solvents and
greener processes. In this context, and thanks to the suc-
cess of adequate modeling tools, accurate experimental
measurements and the optimization of the equipments at
industrial scale, the use of scCO2 has transitioned, over the
past twenty-five years, from a laboratory-based research
to a commercial reality, with applications in high-value
products such as in pharmaceuticals, nutraceuticals, foods
and flavors, polymers and chemicals, as well as in bulk
commodity products such as textiles, biofuels and cement.
After a general overview, we will address some of
the recent applications of CO2 in which our team has been
involved, including the recovery of solutes from ionic liquids
with CO2 or separation of ionic liquids from organic sol-
vents by CO2 [1,2], the preparation of organic-inorganic
materials by scCO2 for CO
2 capture and other applications
[3-5], the use of scCO2 to extract high added value products
and the scCO2 role in the biofuel arena. Modeling and ad-
vanced experimental techniques, from small reactors to
STATE OF SCFs&T | FUTURE DIRECTIONS AND PROGRESS IN COMMERCIALIzATION 27
pilot plants have been used in order to move the technol-
ogy forward.
This work is part of a CENIT project SOST-CO2 be-
longing to the Ingenio 2010 program financed by CDTI,
Science and Innovation Department, Spanish Government,
aiming at reducing the emissions of CO2 in Spain and de-
veloping new industrial and sustainable uses of CO2. The
project is lead by the company Carburos Metálicos, from
Air Products Group, and it comprises 14 other companies
and 31 research institutions. Support for this work from
Air Products and the Spanish Government through project
CEN-2008-1027 (CENIT SOST-CO2) is gratefully acknowl-
edged. Additional support was provided by the Spanish
Government (CTQ2008-05370/PPQ, CTQ2011-23255) and
by the Catalan Government (2009SGR-666).
The work presented here has been done in collab-
oration with F. Llovell, S. Builes, O. Vilaseca, R.M. Marcos,
R. Solanas, J. Torres, P. López-Aranguren and C. Domingo.
Their contributions and continuous support is very much
appreciated.
REFERENCES
[1] F. Llovell, O. Vilaseca, L. F. Vega, Thermodynamic modeling of imidaz-olium-based Ionic Liquids with the [PF6] anion by means of the soft-SAFT EoS, Separation Science & Technology, 47 (2011) 399-410.
[2] F. Llovell, E. Valente, O. Vilaseca, L. F. Vega, Modeling complex asso-ciating mixtures with [Cn-mim][Tf2N] ionic liquids: predictions from the soft-SAFT equation, J. Physical Chemistry B., 115 (2011) 4387-4398.
[3] P. López-Aranguren, J. Saurina, L. F. Vega, C. Domingo, Sorption of try-alkoxysilane in low-cost porous silicates using a supercritical CO2 meth-od, Microporous and Mesoporous Materials, 148 (2012) 15-24.
[4] S. Builes, L. F. Vega, Effect of Immobilized Amines on the Sorption Properties of Solid Materials: Impregnation versus Grafting, Langmuir, 9 (2013) 199-206.
[5] S. Builes, P. López-Aranguren, J. Fraile, L. F. Vega, C. Domingo, Alkylsilane- Functionalized Microporous and Mesoporous Materials: Molecular Simulation and Experimental Analysis of Gas Adsorption, J. Physical Chemistry C, 116 (2012) 10150-10161.
COMMERCIALIzATION OF SUPERCRITICAL FLUID PROCESSES AND PRODUCTS — A PERSPECTIVE
29
COMMERCIALIzATION OF SUPERCRITICAL FLUID PROCESSES AND PRODUCTS — A PERSPECTIVE
Jerry W. King CFS – University of Arkansas;
1965 E. Spinel Link #7; 72701, Fayetteville, AR, USA; E-mail: [email protected]
Commercializing processes and products that involve pres-
surized fluids technology has been on-going for over four
decades. This presentation is focused on the current sta-
tus of processes and products contrasted with and future
trends/needs as well as application areas. The success of
applying a pressurized or supercritical fluid for processing
lies in producing a product derived by either extraction-frac-
tionation-reaction methods that is cost competitive with
existing products, or fulfills a need where the end user is
willing to pay a premium for the benefits derived from the
“supercritical” product. This can be challenge in emerging
economies such as representing by the BRIC (Brazil-Russia -
-India-China) countries as typified by consumer attitudes
toward particular products, such as EPA and omega-3 fat-
ty acid nutraceutical supplements.
It is interesting to examine platforms, not only in
terms of integration of pressurized processing options in-
cluding critical fluids, but also where the energy versus
higher value product use of a renewable substrate perhaps
are in competition with one another. For example, consid-
er the case of oils used for either renewable biodiesel ver-
sus processing them with scCO2 to extract higher-value
nutraceutical ingredients. This competition is particular-
ly acute when the renewable oil source is from algae where
30 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
the oil can be converted to biodiesel via several routes
which can use supercritical media (scCO2, supercritical
methanol, etc.), or be processed using scCO2 for its omega
fatty acid content (market potential: 2011 — $25.4 billion;
2016 — $34.7 billion — 6.4% rate increase compounded
annually), or antioxidant content such as astaxanthin
(~$10,000/kg). Several case examples will be provided
where a common feed stock such as algae can be frac-
tionated to produce a multiple product portfolio having
diversified economic benefit.
Today SFE is driven by the scCO2 processing of nu-
traceutical/functional food ingredients. Newer SFE “ultra-
high” pressure processing plants are now operational and
employ extraction pressures up to and beyond 1000 bar.
Such conditions permit the co-extraction of synergistic
components, i.e., both non-polar and polar compounds
which can be rationalized based on their solubility param-
eters relative to that exhibited by scCO2 at higher pressures
and temperatures. It is more difficult to discern commer-
cial products realized by using columnar fractionation or
SFC that are being produced on a commercial scale de-
spite considerable research in these areas. Likewise prom-
ising reaction chemistries conducted in the presence of
supercritical fluids, such as enzyme-based conversions,
hydrogenation, etc. have yet to produce commercially-vi-
able products.
The use of pressurized water, both in its sub- and
super-critical fluid state has been undertaken now for over
three decades. The use of pressurized water ranges over
a considerable temperature range augmented by appro-
priate pressures based on its phase diagram. These range
from very low pressure conditions for subcritical water
extraction (SWE) to higher pressures/temperatures applied
in treating renewable energy feed stocks for both chemical
STATE OF SCFs&T | FUTURE DIRECTIONS AND PROGRESS IN COMMERCIALIzATION 31
and fuel utilization. SWE has received much attention due
to the many studies conducted on agriculturally-based
renewable materials, and the promise that it can replace
organic solvent-based processes — hydroethanolic extrac-
tion. The future development of this processing technique
is very dependent, as most of the high temperature bio-
mass processing technologies on the development of a
continuous solids feeding system compatible of operating
at higher temperatures and variable pressures. Our stud-
ies at the University of Arkansas with modified expeller
or auger delivery systems have shown modest success
when applied for processing anti-oxidant botanical ex-
tracts. The compatibility and cost of such systems can be
reduced by applying conventional 316 SS alloys up to the
critical point of water, beyond which biomass reforming,
pyrolysis, and gasification require more expensive equip-
ment.
Perhaps the ultimate criterion of the worth of R &
D using high pressure fluids is whether a long term com-
mercial product is realized as the end goal. Examples of
successful product platforms have been reviewed by au-
thor in the past — the question is what does the future
hold? As noted above, developments in SFE are driven by
high-value extracts containing ingredients that can pro-
vide flavor, antioxidant, or desirable physical properties
due to their multi-component composition. Examples of
such extracts occur from applying SFE to algae and certain
marine-derived products such as krill oil, where the syn-
ergistic benefit of extracts containing omega-fatty acids,
naturally-derived pigments, and phospholipids have been
verified in clinical studies. The extension of these extracts
as medicines will require that SFE and related processes
be conducted under GMP (Good Manufacturing Practice)
conditions, which is different from the criteria applicable
32 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
under GLP and GRAS regulations. To date in the develop-
ment of SCF-based processes, GMP conditions are not
always adhered to, but some GMP protocols have been
recorded in the preparing particles for the pharmaceutical
industry using various pressurized fluids, and similarly in
the use of SFC. Despite industrial interest in sub-critical
water extracts, such products are difficult to verify in the
marketplace. The promise of chemicals and extractives
produced by high pressure aqueous processing has often
been reported, but downstream purification of these com-
plex extracts and the separation of these components from
aqueous media remains a problem due to the additional
unit processing costs. In addition, sometimes conversion
of these extracted solutes by reaction chemistry is required.
Two examples relevant to the above problems will be cit-
ed — the extraction of natural polyphenolic antioxidants
using SWE or CO2-based extraction, and obtaining the
cosmetic ingredient, squalane, from sugar cane biomass.
Such extracts are now finding an increased use in the per-
sonal care industry and pertinent products will be shown.
The consumer is becoming increasingly aware of what
differentiates a supercritical fluid-derived product from
those obtained via conventional or alternative routes. Ex-
amples will be shown of “embracing” the supercritical
fluid logo in product advertising as well as benefits that
accrue from using a supercritical fluid process, such as
the problem with solvent residuals in products. The latter
problem beckons for a “supercritical fluid solution”, due
to more stringent legislation that is being applied on prod-
ucts intended for health food industry, cosmetic applica-
tions, and for medical use. Such products include both
extracts and raffinates — saleable products left over after
critical fluid processing. Several examples of the latter
will be noted from the oilseed medicinal area and marine/
STATE OF SCFs&T | FUTURE DIRECTIONS AND PROGRESS IN COMMERCIALIzATION 33
algal-derived products. While economic analysis of produc-
tion costs in the case of supercritical fluid-based process-
ing is important, it is not the only factor which determines
the success of commercial product. Derived products/pro-
cesses which appeal to the altruistic sensibilities of the
end consumer make critical fluid-based processing attrac-
tive. The utilization of “green” processing when coupled
with a bio-renewable/sustainable production platform can
be used advantageously in the marketing of end products
— particularly when they involve the utilization of CO2.
Many model or hypothetical bio-refineries with integrated
processing utilizing critical fluids have been envisioned,
but to date only discrete unit processes have been studied
in detail. Adoption of supercritical fluid-based technolo-
gies commercially can be greatly aided by utilizing “mo-
bile” plants that allow demonstration of the merits of the
technology within existing production facilities.
35
SUPERCRITICAL FLUIDS IN ENERGy AND BIOFUEL APPLICATIONS
Richard L. smith Jr.Tohoku University;
Aoba-ku, Aramaki Aza Aoba 6-6-11, Sendai, Miyagi-ken, 980-8579, Japan;
E-mail: [email protected]
Supercritical fluids have application in energy and biofu-
el processes in their use as (a) working fluids, (b) reaction
solvents, (c) mass transfer promoters, (d) heat transfer pro-
moters and (e) separation agents. This work introduces
applications of supercritical fluids that demonstrate some
of their unique technological advantages and presents
aspects of a proposal that uses supercritical CO2 with hy-
drogen and ionic liquids for the conversion of biomass to
biofuels. Supercritical fluids are being used as working
fluids in next-generation systems for refrigeration [1],
hot-water heating [2], heat-pump [3], natural gas [4-6],
geothermal [7], ultrasupercritical boiler [8] applications.
In these applications, the homogeneous phase conditions
of the transcritical state change gives highly-efficient en-
ergy transport. Supercritical fluids can be used as reaction
solvents in next-generation chemical processes for pro-
ducing biodiesel fuel from oilseed crops [9-14]. There are
a number of proposals for using supercritical fluids such
as methanol [12], combinations with acetic acid [14], meth-
yl acetate [13], and dimethylcarbonate [10], each with its
distinctive advance according to the use of raw materials
and chemical products and by-products. Use of supercrit-
ical methyl acetate as reaction solvent for triglycerides
36 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
gives triacetin and avoids the formation of glycerol [9].
Use of supercritical dimethyl carbonate gives glycerol car-
bonate as a value-added by-product [10]. In this strategy,
the solvent is a supercritical fluid that acts not only as a
solvent but also as a reactant and promotes heat and mass
transfer. In hydrothermal methods, water, which is some-
times combined with additives, is used to pretreat or con-
vert biomass into feedstocks suitable for biofuel production
[15-18]. In this strategy, the self-ionization of water is ex-
ploited to promote hydrolytic reactions and cellulose de-
polymerization. Ionic liquids, which are organic salts that
are commonly liquid at room temperature, offer an inter-
esting possibility to transform biomass into biofuels [19].
The ionic liquid can act not only as a solvent for biomass,
but also as a homogeneous catalyst for transforming bio-
mass substrates into biofuels [19]. In this strategy, an
ionic liquid is used as solvent for biomass, cellulose, or a
carbohydrate substrate. Many approaches have been tak-
en in the literature. In Qi et al. [20], cellulose is converted
into 5-hydroxymethylfurfural in high yields via a two-step
process that involves water addition to the reacting mix-
ture. In these systems, as biomass or its related constit-
uents are dissolved into an ionic liquid, the viscosity of
the solution greatly increases thus causing the mass trans-
fer to become greatly limited. When the viscosity is re-
duced by addition of organic solvents or a soluble gas,
such as supercritical CO2, many reactions can proceed
smoothly [21].
A proposal that we are examining in this work is
the transformation of biomass into fuels via catalytic meth-
ods [22]. In Chen et al. [22], sugars and polyols undergo
direct conversion into n-hexane and n-pentane via catalyst
in a triphasic (water-n-dodecane-hydrogen) system. For
glucose the reaction is:
STATE OF SCFs&T | FUTURE DIRECTIONS AND PROGRESS IN COMMERCIALIzATION 37
C6H
12O
6 + 7H
2 -> C
6H
14 + 6 H
2O (1)
Although the method and catalyst give outstanding
results (99.9% conversion, 94+% yield), long reaction times
(84 h) are required due to mass transfer limitations of both
reactants and products. In this work, we consider the use
of supercritical CO2 in the objective for improving the re-
action efficiency of Eq. (1) and the use of ionic liquids to
expand the application of the catalytic system.
REFERENCES
[1] Y. T. Ge, S. A. Tassou, I. N. Suamir, Prediction and analysis of the sea-
sonal performance of tri-generation and CO2 refrigeration systems in
supermarkets, Applied Energy, 112 (2013) 898-906.
[2] S. G. Kim, Y. J. Kim, G. Lee, M. S. Kim, The performance of a transcrit-
ical CO2 cycle with an internal heat exchanger for hot water heating,
International J. Refrigeration, 28 (2005) 1064-1072.
[3] J. Stene, Residential CO2 heat pump system for combined space
heating and hot water heating, International J. Refrigeration, 28 (2005)
1259-1265.
[4] W. Lin, N. Zhang, A. Gu, LNG (liquefied natural gas): A necessary part
in China’s future energy infrastructure, Energy, 35 (2010) 4383-4391.
[5] E. Querol, B. Gonzalez-Regueral, J. García-Torrent, A. Ramos, Available
power generation cycles to be coupled with the liquid natural gas (LNG)
vaporization process in a Spanish LNG terminal, Applied Energy, 88
(2011) 2382-2390.
[6] Y. Song, J. Wang, Y. Dai, E. Zhou, Thermodynamic analysis of a tran-
scritical CO2 power cycle driven by solar energy with liquified natural
gas as its heat sink, Applied Energy, 92 (2012) 194-203.
[7] X. L. Gu, H. Sato, Performance of supercritical cycles for geothermal
binary design, Energy Conversion and Management, 43 (2002) 961-971.
[8] S. Kaneko, K. Yamamoto, M. Kinoshita, Y. Wakabayashi, Y. Iida, Design
and operation experience of a 1000 MW ultra supercritical coal fired
boiler with steam condition of 25.4 MPa 604/602 °C, Technical Review
— Mitsubishi Heavy Industries, 36 (1999) 61-65.
[9] F. Goembira, S. Saka, Optimization of biodiesel production by super-
critical methyl acetate, Bioresource Technology, 131 (2013) 47-52.
[10] Z. Ilham, S. Saka, Optimization of supercritical dimethyl carbonate
method for biodiesel production, Fuel, 97 (2012) 670-677.
38 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
[11] J. S. Lee, S. Saka, Biodiesel production by heterogeneous catalysts
and supercritical technologies, Bioresource Technology, 101 (2010)
7191-7200.
[12] E. Minami, S. Saka, Kinetics of hydrolysis and methyl esterification for
biodiesel production in two-step supercritical methanol process, Fuel,
85 (2006) 2479-2483.
[13] S. Saka, Y. Isayama, A new process for catalyst-free production of bio-
diesel using supercritical methyl acetate, Fuel, 88 (2009) 1307-1313.
[14] S. Saka, Y. Isayama, Z. Ilham, X. Jiayu, New process for catalyst-free
biodiesel production using subcritical acetic acid and supercritical meth-
anol, Fuel, 89 (2010) 1442-1446.
[15] R. Feiner, N. Schwaiger, H. Pucher, L. Ellmaier, P. Pucher, M. Sieben-
hofer, Liquefaction of pyrolysis derived biochar: A new step towards
biofuel from renewable resources, RSC Advances, 3 (2013) 17898-17903.
[16] M. C. Johnson, J. W. Tester, Lipid transformation in hydrothermal pro-
cessing of whole algal cells, Industrial and Engineering Chemistry
Research, 52 (2013) 10988-10995.
[17] Z. Liu, A. Quek, R. Balasubramanian, Preparation and characterization
of fuel pellets from woody biomass, agro-residues and their corre-
sponding hydrochars, Applied Energy, 113 (2014) 1315-1322.
[18] H. Ramsurn, R. B. Gupta, Deoxy-liquefaction of switchgrass in super-
critical water with calcium formate as an in-situ hydrogen donor, Biore-
source Technology, 143 (2013) 575-583.
[19] Z. Fang, R. L. Smith Jr., X. Qi, Production of biofuels and chemicals
with ionic liquids, in: Biofuels and Biorefineries 1; Springer, 2013.
[20] X. Qi, M. Watanabe, T. M. Aida, R. L. Smith Jr., Catalytic conversion
of cellulose into 5-hydroxymethylfurfural in high yields via a two-step
process, Cellulose, 18 (2011) 1327-1333.
[21] X. Qi, M. Watanabe, T. M. Aida, R. L. Smith Jr., Efficient catalytic con-
version of fructose into 5-hydroxymethylfurfural in ionic liquids at room
temperature, ChemSusChem, 2 (2009) 944-946.
[22] K. Chen, M. Tamura, Z. Yuan Y. Nakagawa, K. Tomishige, One-pot con-
version of sugar and sugar polyols to n-alkanes without C-C dissociation
over the Ir-ReOx/SiO2 catalyst combined with H-ZSM-5, ChemSus-
Chem, 6 (2013) 613-621.
OVERVIEW/PLENARy LECTURES ON ThE ROLE OF SUPERCRITICAL FLUIDS AND TEChNOLOGy (SCFs&T)
SCFs&T for Bio-based Fuel processes
41
wATER — A “MAGIC” TOOL TO CONVERT BIOMASS?
Andrea KruseUniversity Hohenheim;
Garbenstrasse 9, 70599, Stuttgart, BaWü, Germany; E-mail: [email protected]
Fresh biomass could be dried and combusted or gasified
by a “dry process”. Such processes are under development
and are similar to fossil coal processing. The motivation
for such R&D work is the wish to become more indepen-
dent of the vanishing fossil resources for energy supply and
chemically produced products. However, drying is asso-
ciated with considerable costs at high water content of
80-90% in green plants. On the other hand, most of the up
to now unused, and therefore most attractive, biomass has
such high water content. For such “wet” or “green” bio-
mass, hydrothermal biomass conversion methods are su-
perior. The expression “hydrothermal” is originally used
in geology to name reaction in water at increased tem-
peratures and pressures. Depending on the reaction con-
ditions, different fuels or basic chemicals, to produce e.g.
polymers, can be formed. These fuels are a solid, liquid
(with a very high viscosity) or gaseous. The selectivity
towards these products is usually higher and the tempera-
tures lower than in the analogous dry processes. The rea-
son for the lower temperature is the high reactivity of
biomass in water. The reasons for the high selectivity are
the lower temperature and the change of water properties
with reaction conditions. All hydrothermal biomass con-
version processes take benefit of the special properties of
42 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
hot compressed liquid or supercritical water. At subcritical
conditions, the ionic product of water is higher as at am-
bient conditions. The reason is the endothermic character
of the self-dissociation of water. The high H+ and OH-
concentrations enable rather high reaction rates of reac-
tions usually require the presence of acids and bases. In
other cases, water itself works as catalyst, fulfilling the
role usually done by H+ or OH-. At supercritical conditions
(above 374 °C and 22.1 MPa) water behaves like a non-po-
lar solvent but the water molecules are still polar. These
unique properties mainly avoid unwanted polymerization
by splitting large molecules and solving the products.
This hydrothermal biomass conversion processes
introduced here are:
I. Pretreatment. At lower temperatures we found dif-
ferent pre-treatment methods, e.g. simply cooking
of biomass. The (exothermic) degradation of bio-
mass starts at around 170 °C.
II. Hydrothermal Carbonization. At around 200 °C, there
are the operation conditions of hydrothermal car-
bonization (HTC) of biomass. Here artificial coal is
produced with very high yield, often in the presence
of an acid as catalyst. From the chemical point of
view and at this condition, most of the biomass is
split first. The splitting of carbohydrates like cellu-
lose and hemicelluloses is supported by the high
ionic product of water. The product, glucose con-
verts partially to fructose. If the reaction is stopped
at this point the products glucose and fructose can
be feed for microorganism. By water elimination,
hydroxymethylfurfural (HMF) from fructose is pro-
duced. HMF is an important platform chemical
which may substitute compounds from fossil oil to
SCFs&T FOR BIO-BASED FUEL PROCESSES 43
produce a wide range of products, e.g. polymers. If
the reaction is not stopped at this stage, a solid prod-
uct is formed by polymerization. This brown or black
product has nearly the heating value of fossil lig-
nite. Therefore the process is called “Carbonization”.
III. Aqueous Reforming. At slightly higher temperature
hydrogen can be produced from compounds origi-
nating from biomass using noble metal catalysts.
This process, called aqueous reforming, works be-
cause of thermodynamic reason only at very low
concentrations and up to now not with real bio-
mass. The hydrogen can be use for in-situ hydro-
genation of the feedstock to produce hydrocarbons,
if a suitable catalyst is present.
IV. Hydrothermal liquefaction. At around 300 to 350 °C
biomass liquefaction occurs. This process developed
originally by the company Shell as hydrothermal
upgrading, lead to a high viscous product with a
lower oxygen content and higher heating valve than
the product of dry biomass liquefaction (fast pyrol-
ysis). In some cases (alkali) catalysts are applied
and recently the focus is on liquefaction of algae.
A special application is the splitting of lignin to
phenols which are precursors of resins. In this case
temperatures of around 400 °C are useful. Lignin is
the only common renewable resource for aromatic
compounds, which are produced from fossil oil today.
V. Near critical gasification. Near the critical point the
catalyzed hydrothermal gasification is conducted.
Methane and CO2 are the main products and het-
erogeneous catalysts are necessary. In this tempera-
ture range methane is the main burnable product in
equilibrium, but noble metal catalysts are necessary
because methane formation is kinetically inhibited.
44 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
VI. Supercritical water gasification. This process is called
supercritical water gasification, because of the re-
actions conditions above the critical point of water.
The wished product is hydrogen. Usually tempera-
tures at or above 600 °C are applied because only
at high temperature hydrogen is the preferred prod-
uct in equilibrium. Catalysts are salts included in
the biomass. Heterogeneous, e.g. noble metals as
well as carbon catalysts are not necessary but often
used to reduce the temperature or to increase the
gas yield at higher dry mass content and concen-
trations, respectively.
Depending on the reaction conditions, a wide range
of products like different energy carriers (gaseous, liquid
or solid) or platform chemicals are available. This is a con-
sequence of the change in the water properties with tem-
perature and density. The variability of the reaction medium
is unique and is the key for the use of “wet” or “green”
biomass. Water is a natural ingredient of biomass which
becomes the reaction medium by heating-up. This typical
property of hydrothermal reactions opens a lot of possibil-
ities e.g. to combine them with biochemical reactions that
are also occurring in water. On the first view hydrothermal
processes seems to be an important tool for a “bio-refin-
ery” to produce various products by usage of the complete
plants. On the other hand there are some challenges.
Which challenges are the most important depend on the
temperature or wished product. E.g. for hydrothermal car-
bonization and hydrothermal liquefaction the treatment
of the waste water is important. For the processes using
heterogeneous catalyst, poising is the largest hurdle to
overcome. For supercritical water the strong conditions
limits the reactor material lifetime.
FUNDAMENTALS OF ThE SUPERCRITICAL wATER OxIDATION PROCESS FOR AN EFFICIENT AND CLEAN ENERGy PRODUCTION
45
FUNDAMENTALS OF ThE SUPERCRITICAL wATER OxIDATION PROCESS FOR AN EFFICIENT AND CLEAN ENERGy PRODUCTION
Maria José coceroSchool of Industrial Engineering,
Sede Mergelina Chemical Engineering Department, Valladolid University;
47011, Valladolid, Spain; E-mail: [email protected]
high pressurized water (HPW) / Supercritical water (SCW)
properties as reaction media. Water offers many favor-
able properties at elevated temperatures and pressures
that make it therefore an excellent solvent and reaction
medium for numerous applications. In the vicinity of the
critical point the thermodynamic properties of water change
drastically compared to those of liquid water [1]. The den-
sity (ρ), dielectric constant (ε) and ionic product of water
(Kw) from 0 ºC to 600 ºC at a pressure of 25 MPa can be
calculated according to the equations developed in liter-
ature [2,3]. The change in the dielectric constant is pro-
portional to the density and inversely proportional to the
temperature. Hydrogen bonds present a behavior analo-
gous to that of the dielectric constant. Another important
property of the organic reaction media is the ionic product
of water. Around 300 ºC the value of the ionic product of
water reaches its maximum (1.10-11), which creates a me-
dium with high H+ and OH- concentrations, thus favoring
in this way acid/basis catalyzed reactions. Above the crit-
ical temperature of water (374 ºC), the Kw decreases dras-
tically (1.10-25) [4]. At higher pressures (P>60 MPa) the
Kw again presents values similar to those of ambient wa-
ter. The significant drop in the dielectric strength leads to
46 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
a considerable increase in the solubility of hydrocarbons
in supercritical water. In correlation, the solubility of inor-
ganic salts reduces drastically. Supercritical water acts
like a non-polar dense gas with solvation properties equiv-
alent to those of low polar organic solvents. Additionally
the gases as CO2, O
2, N
2 are completely miscible in SCW
[1]. These physical properties are the reason to consider
supercritical water as an ideal media for the oxidation of
organic compounds. The reaction takes place in a single
phase, avoiding interfacial mass transfer resistances. Su-
percritical Water Oxidation process. The process known
as supercritical water oxidation (SCWO) consists of the ho-
mogeneous oxidation of chemical compounds in an aque-
ous medium using air, oxygen or hydrogen peroxide as
oxidizing agent, at temperatures and pressures above the
critical point of water (374 ºC and 22.4 MPa). The SCWO
takes place in three steps: Feed preparation and pressur-
ization; Reaction and solids separation; and Depressuriza-
tion and heat recovery [1]. Technically, the SCWO has the
advantage of simple, fast and homogeneous reactions
without mass transfer limitations. It also has some limita-
tions related to extreme operating conditions and their
effect on the materials equipment. Therefore, the main
challenges of SCWO are corrosion and deposition of salts,
which are being solved by the use of special construction
materials and the development of new reactor designs able
to soften the conditions that the materials must resist.
SCWO kinetic can be described by a radically reaction
mechanic, but when the temperature of the mixture is
higher than the auto ignition temperature, supercritical
water oxidation proceeds in the form of flames called hy-
drothermal flames. In general, flames ignited spontaneous-
ly beyond a certain temperature, normally between 400
and 500 ºC. This auto ignition temperature was decreased
SCFs&T FOR BIO-BASED FUEL PROCESSES 47
for higher pressures and fuel concentrations [5]. Hydro-
thermal flames are combustion flames produced in aque-
ous environments at conditions above the critical point of
water (P>221 bar and T>374 ºC).The flame is defined as
the surface where combustion is produced. This surface
separates the oxidant from the fuel in the case of diffusion
or non-premixed flames, in which fuel is injected into the
oxidant. In the case of premixed flames, that is, when the
fuel and oxidant are injected already mixed, the flame is
the surface separating the reagents from the reaction prod-
ucts. In premixed flames, the surface is moving towards
the reagents with a flame front velocity. If this velocity
is the same as the fluid velocity the flame will remain still
in a fixed position. In general, the conditions of the flame
ignition depended on the fuel, the oxidant, and the ratio
of fuel/oxidant and the geometry of the injection system.
SCWO with a hydrothermal flame has a number of advan-
tages over the flameless process. Some of these advan-
tages permit overcoming the traditional challenges that
make the successful and profitable commercialization of
SCWO technology difficult [6]:
� Allow the destruction of the pollutants in residence
times of a few milliseconds: construction of small-
er reactors.
� Reaction with feed injection temperatures near to
room temperature, avoids problems such as plug-
ging and corrosion in a preheating system and ad-
vantages from the operational and energy integration
perspective.
� Higher operation temperatures, improve the energy
recovery Energy by supercritical water oxidation.
48 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
The research group has been very active in the de-
veloping of SCWO process as an efficient and environmen-
tal compatible process for the treatment of wastes [1]. The
SCWO process can reduce significantly the operation time
by using hydrothermal flames. The results showed that
the SCWO technology, using hydrothermal flame, is able
to oxidize high amounts of compounds in residence times
of around 1s, using very compact reactors and producing
CO2, water, salts and energy [7]. Our last contribution is a
new reactor to produce energy. A 650 ºC up-reactor efflu-
ent can be combined with a gas turbine to produce work
and energy. For example, by using the conventional Rankin
cycle to produce 1 MW by SCWO reactor effluent, the pump
and air compressor consume 1,64 MW. The new reactor
allows the production of 1 MW by consuming 0,78 MW, so
this could be a way of producing neat excess energy [8].
REFERENCES.
[1] M. D. Bermejo, M. J. Cocero, AIChE J., 52 (2006) 3933-3951.
[2] W. L. Marshall, E. U. Franck, J. Physical and Chemical Reference Data,
10(2) (1981) 295-304.
[3] M. Uematsu, E. U. Franck, J. Physical and Chemical Reference Data,
9(4) (1980) 1291-13.
[4] N. Akiya, P. E. Savage, Chemical Reviews, 102(8) (2002) 2725-2750.
[5] W. Schilling, E. U. Franck, Berichte der Bunsengesell-schaft für physi-
kalische chemie, 92 (1988) 631-636.
[6] C. Augustine, J. W. Tester, Hydrothermal flames: From phenomeno-
logical experimental demonstrations to quantitative understanding, J.
Supercritical Fluids, 47 (2009) 415-430.
[7] M. D. Bermejo, C. Jiménez, P. Cabeza, A. Matías-Gago, M. J. Cocero,
J. Supercritical Fluids, 59 (2011) 140-148.
[8] P. Cabeza, M. D. Bermejo, C. Jiménez, M. J. Cocero, Water Research,
45(8) (2011) 2485-2495.
OVERVIEW/PLENARy LECTURES ON ThE ROLE OF SUPERCRITICAL FLUIDS AND TEChNOLOGy (SCFs&T)
SCFs&T for New Materials and Materials Processing
51
AEROGELS OF DIFFERENT ORIGINS: A JOURNEy FROM INSULATION MATERIALS TO ADDED-VALUE PRODUCTS OF BIOREFINERy
irina smirnovaUniversity of Technology Hamburg-Harburg;
Eissendorferstr. 38, 21075, Hamburg, Germany; E-mail: [email protected]
Aerogels are known as a special class of nanoporous ma-
terials already since 1930. They are obtained from wet gels
by using a suitable drying technology, usually a supercrit-
ical drying process, able to avoid the pore collapse phe-
nomenon and keep intact the porous texture of the wet
material. Efforts have been traditionally focused on silica
aerogel and carbon aerogel development with a wide range
of applications in different fields, e.g., aeronautics, bio-
medicine, construction, environmental remediation or ag-
riculture. However, among the broad range of possible
applications, just few of them have been commercialized
so far. Main application is the thermal insulation due to
the extremely low thermal conductivity of aerogels. The
main issues behind this situation are the production costs,
associated with the raw materials and with supercritical
fluid extraction needed for the synthesis of aerogels with
low density. Regarding the raw materials, in the last de-
cades it was realized, that aerogels may be produced from
a great variety of different organic and inorganic materials
and are not restricted by traditional matrices like silica or
carbon ones. Moreover, a lot of biopolymers, having an
advantage of biocompatibility were successfully trans-
ferred in an aerogel form. Generally, all materials that can
be obtained as wet gels by the sol-gel process are potential
52 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
candidates to be turned into aerogels after supercritical
drying. New aerogel classes become especially interested
as intelligent insulation materials, allowing to reduce the
thickness of the insulation significantly. Furthermore,
the applications in the pharmaceutical and food areas
seem to be promising even in front of higher production
costs. Also a combination of the aerogels production with
the biorefinery processes can be realized by using of biore-
finery products as raw materials for gelation. This was for
instance demonstrated by using lignin as a precursor. So
far it seems that the outstanding properties of the aerogels
of different origins significantly broaden the spectrum of
their applications and open a way to their commercializa-
tion. On the way from the lab to the production the scale
up of the supercritical extraction step is the main issue.
Here the energy demand can be dramatically reduced by
optimization of the extraction process, which is currently
the main task for aerogel commercialization. Supercritical
extraction (or drying process) overcomes the problems en-
countered with traditional drying methods and preserves
the high open porosity and superior textural properties
of the wet gel in a dry form. Supercritical CO2 is the most
appropriate fluid for supercritical drying of organic aero-
gels due to its mild critical point conditions along with its
GRAS status. However, depending on the sample size and
thickness the residence time in the extractor might be
significant. Here significant efforts for the modeling of the
process with the aim of the process optimization are still
needed.
53
SUPPORTED METALLIC NANOPARTICLES By SUPERCRITICAL DEPOSITION AND ThEIR APPLICATIONS IN ENERGy RELATED TRANSFORMATIONS
can ErkeyDepartment of Chemical and Biological Engineering,
Koç University; 34450 Sarıyer, Istanbul, Turkey;
E-mail: [email protected]
Techniques such as impregnation, co-precipitation and
sol-gel are commonly used to prepare supported nanopar-
ticles. However, it is generally difficult to control the phys-
ical properties of the particles, such as the particle size
and distribution, and the metal concentration in the ma-
terials. The supercritical deposition (SCD) technique in-
volves the dissolution of a metal precursor in a supercritical
fluid (SCF) and the exposure of a substrate to the solution.
After adsorption of the precursor on the substrate surface,
the metallic precursor is converted to its metal form using
a number of methods resulting in nanoparticles at the sur-
face of the substrate. Supercritical deposition especially
using supercritical carbon dioxide (scCO2) has numerous
advantages including the elimination of organic solvents
and solvent residue on the substrates. Furthermore, fast-
er mass transfer rates compared to liquids result in faster
rates of deposition.
A wide variety of metal nanoparticles including Pt,
Ru, Ni, and Cu@Cu2O were prepared using SCD on a wide
variety of porous substrates including alumina, silica, car-
bon nanotubes, carbon and resorcinol formaldehyde aero-
gels. Uniformly distributed nanoparticles with a narrow
particle size distribution are often obtained using SCD.
54 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
The size of the nanoparticles can be tuned by adjusting
the supercritical deposition parameters such as metal pre-
cursor concentration in the fluid phase, temperature and
the pressure of precursor adsorption, and the reduction
temperature. The nature of the support material is also an
important factor which effects the morphology of the nano-
particles. The thermodynamics of adsorption of the metal
precursors are generally quantified by the adsorption iso-
therms for the precursors between the fluid phase and the
porous substrate which usually follow Langmuir behavior.
The kinetics of adsorption can adequately be described
by using a mass transfer model based on diffusion in pore
volume and local equilibrium at the surface of the support.
In some cases, catalysts prepared using this technique
have been found to be superior in activity to catalysts pre-
pared by conventional techniques.
The technique has recently been extended to prepa-
ration of supported bimetallic nanoparticles. Simultaneous
Supercritical Deposition involves the dissolution of two
metal precursors in a SCF and exposure of a substrate to
this solution. Metal precursors are then physisorbed or
chemisorbed on the support in the presence of SCF. Ad-
sorbed metal precursors can then be decomposed to end
up with supported metals or metal oxides through various
processes. Carbon aerogel supported Pt-Cu alloy nano-
particles were prepared using the precursors dimethyl
(1,5-cyclooctadiene), platinum (II) (Pt(cod)me2) and bis
(1,1,1,3,5,5,6,6,6-nonafluorohexane-2,4-diiminate) copper
in the presence of scCO2. Binary adsorption isotherms were
successfully predicted using the Ideal Adsorbed Solution
Theory by using single component adsorption isotherm
parameters alone. Alloy nanoparticles were formed via
the thermal decomposition of metal precursors. The alloy-
ing of Pt and Cu within the nanoparticles was character-
SCFs&T FOR NEw MATERIALS AND MATERIALS PROCESSING 55
ized via XRD peak shifts at various Pt/Cu ratios, and XPS
data pointed out that the surfaces of these Pt-Cu alloy
nanoparticles were enriched in Pt. The particle size of the
nanoalloys was found to increase with increasing copper
fraction. Nevertheless, the particle size distribution was
very uniform in all cases.
Reactive supercritical deposition where the precur-
sors chemisorb on the surface by reacting with the func-
tional groups on the surface is another variation of the
technique which can be used to prepare bimetallic sys-
tems. Recently, USY zeolite supported Ni-W hydrocracking
catalysts were prepared via the simultaneous chemisorp-
tion of tungsten hexacarbonyl (W(CO)6) and Nickel (II)
acetylacetonate or bis (1,1,1,3,5,5,6,6,6-nonafluorohex-
ane-2,4-diiminate) nickel in the presence scCO2. Materials
were then calcined at ambient pressure. FTIR indicated
the chemisorption of metal precusors on USY zeolites. XRF
analysis showed an increase in the W loading with an
increase in both the initial W(CO)6 concentration in scCO
2
and the deposition time. Temperature Programmed De-
sorption experiments carried out using ammonia suggest-
ed that at the same loading the acid site distribution was
different from catalyst prepared by incipient wetness. More-
over, the proportion of the stronger acid sites was higher
for the catalysts prepared using simultaneous supercritical
deposition (53.3% of the total acid sites) as compared to
that of the incipient wetness (33.2% of the total acid sites)
indicating that the technique has potential to lead to de-
velopment of catalysts with properties that are different
than catalysts prepared by conventional techniques.
57
DENSE CO2 AS AN ENABLING MEDIUM FOR INTENSIFIED CATALyTIC AND PARTICLE FORMATION PROCESSES
Bala subramaniamCenter for Environmentally Benefi cial Catalysis,
University of Kansas; 1501 Wakarusa Drive, Suite A110, 66047, Lawrence, KS, USA;
E-mail: [email protected]
The foremost guiding principles underlying the sustain-
able process development include process intensification
at mild conditions, minimization of waste and of adverse
environmental footprints, and enhancement of inherent
process safety [1]. Many groups, including ours, have
uniquely exploited near-critical media to develop novel
catalytic process concepts that admit these attributes.
Central to these innovations is the recognition that with
relatively moderate changes in pressure, it is possible to
“tune in” unique fluid properties (liquid-like density and
gas-like transport) with near-critical media. These con-
cepts have numerous novel applications in heterogeneous
catalysis such as: (a) facile desorption and transport of
heavy molecules (including coke precursors) in mesoporous
catalysts, alleviating pore-diffusion limitations and im-
proving catalyst effectiveness; (b) enhancing product se-
lectivity; and (c) exploiting the enhanced heat capacity of
near-critical media to ameliorate parametric sensitivity in
exothermic reactions. These features have been demon-
strated for several classes of reactions such as isomeri-
zations, hydrogenations, Fischer-Trøpsch synthesis and
alkylations [1].
During the past decade, our group has exploited
the pressure-tunable properties of gas-expanded liquids
58 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
(GXLs) in a variety of homogeneous catalytic systems [2].
At ambient temperatures, gases such as carbon dioxide
(CO2) and light hydrocarbons (such as propylene and eth-
ylene) are close to their critical temperatures (i.e., between
0.7 -1.3 Tc). When these gases are mildly compressed (to
tens of bars) at ambient temperatures, they dissolve in
most conventional solvents and volumetrically expand
them. The increased free volume of the GXL phases ac-
commodates permanent gases such as O2, H
2 and CO in
unusually high concentrations. For example, O2 and light
olefin concentrations are increased by one or two orders
of magnitude in GXLs at ambient conditions, relative to
conventional solvents, with similar increases in reaction
rates [3].
This lecture will also highight several novel GXL-
based catalytic reaction engineering concepts. These in-
clude (a) highly selective hydroformylation of higher olefins
at mild conditions (~40 bars, 60 °C) employing soluble
polymer-supported homogeneous catalysts which are eas-
ily retained in solution by membrane filtration [4]; (b) in-
herently safe liquid phase ethylene epoxidation process
that totally eliminates CO2 formation as a byproduct [5];
(c) a spray reactor concept for the single step formation of
high purity terephthalic acid with reduced solvent burning
(i.e., reduced carbon footprint) [6].
Supercritical CO2 has also been exploited to synthe-
size nanomaterials of active pharmaceutical ingredients
[7] and transition metal complexes with unique function
[8]. This talk will describe a continuous GMP-compliant
process for producing nanoparticles.
REFERENCES
[1] B. Subramaniam, C. J. Lyon and V. Arunajatesan, Applied Catalysis B:
Environmental, 37(4) (2002) 279-292.
SCFs&T FOR NEw MATERIALS AND MATERIALS PROCESSING 59
[2] P. G. Jessop and B. Subramaniam, Chemical Reviews, 107(6) (2007)
2666-2694.
[3] M. Wei, G. T. Musie, D. H. Busch and B. Subramaniam, J. American
Chemical Society, 124(11) (2002) 2513-2517.
[4] Z. Xie, J. Fang, S. K. Maiti, W. K. Snavely, J. A. Tunge and B. Subrama-
niam, AIChE J. (2013) DOI: 10.1002/aic.14142.
[5] M. Ghanta, H-J Lee, D. H. Busch and B. Subramaniam, AIChE J., 59
(2013) 180-187.
[6] M. Li, F. Niu, X. Zuo, P. D. Metelski, D. H. Busch and B. Subramaniam,
Chemical Engineering Science (2013). Available in: http://dx.doi.org/
10.1016/j.ces. 2013.09.004i.
[7] B. Subramaniam, R. A. Rajewski and W. K. Snavely, J. Pharmaceutical
Sciences, 86 (1997) 885-890.
[8] C. A. Johnson, S. Sharma, B. Subramaniam and A. S. Borovik, J. Ameri-
can Chemical Society, 127(27) (2005) 9698-9699.
PROCESSING AND PRODUCTION OF NEW DRUGS AND ChEMICALS WITh COMPRESSED FLUIDS
61
PROCESSING AND PRODUCTION OF NEW DRUGS AND ChEMICALS WITh COMPRESSED FLUIDS
nora ventosa, santi sala, Elisa Elizondo, María Muntó, ingrid cabrera, Alba córdoba, Evelyn Moreno,
paula Rojas, Lidia ferrer, Jaume vecianaInstitut de Ciència de Materials de Barcelona (CSIC)
and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN);
Campus Universitari de Bellaterra, E-08193 Cerdanyola, Spain; E-mail: [email protected]
The obtaining of particulate micro and nanostructured
molecular materials at large scale and the understanding
of how to manipulate them at nanoscopic and supramo-
lecular level are currently playing a crucial role in drug
delivery and clinical diagnostics [1-3]. It has been observed
that polymeric nanoparticles, micelles, microemulsions,
nanosuspensions, nanovesicles, and nanocapsules are ef-
ficient drug carriers that can significantly help to develop
new drug delivery routes, more selective and efficient dis-
ease-detection systems, drugs with a higher permeability
to biological membranes with controlled released profiles,
and to enhance their targeting towards particular tissues,
cells or intracellular compartments.
The potential of “bottom-up” strategies, based on
molecular self-assembling, is much larger than that of
“top-down” approaches for the preparation of such micro-
and nanostructures. For instance, by precipitation proce-
dures it should be possible to control particle formation,
and hence particle size and size distribution, morphology
and particle supramolecular structure. However, conven-
tional precipitation/crystallizations from liquid solutions
62 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
have serious limitations and are not adequate for produc-
ing such nanoparticulate materials at large scale with the
narrow structural variability, high reproducibility, purity
and cost needed to satisfy the high-performance require-
ments and regulatory demands dictated by the EMA and
US FDA agencies.
The solvent power of compressed fluids (CFs), either
in the liquid or supercritical state, can be tuned by pres-
sure changes, which propagate much more quickly than
temperature and composition solvent changes. Therefore,
using compressed solvent media, it is possible to obtain
supramolecular materials with unique physicochemical
characteristics (size, porosity, polymorphic nature morphol-
ogy, molecular self-assembling, etc.) unachievable with
classical liquid media [4]. Small changes in temperature
and pressure of CFs result in large but homogenous chang-
es in the fluid’s density, and hence in its solvent power.
This tunable range in density (solvation ability) cannot be
achieved so easily with any conventional liquid solvent.
The most widely used CF is compressed CO2 (cCO
2), which
is non-toxic, non-flammable, cheap and easy recyclable.
It has gained considerable attention, during the past few
years as a “green substitute” to organic solvents and even
to water in industrial processing. During the past few years,
CFs based technologies, in particular precipitation proce-
dures, are attracting increasing interest for the preparation
of particulate molecular materials with application in the
field of drug-delivery and nanomedicine [5-10].
In this presentation a simple one-step and scale-up
methodology for preparing multifunctional nanovesicle -
bioactive conjugates will be presented. This method is
readily amenable to the integration/encapsulation of mul-
tiple components, like peptides, proteins, enzymes, into
the vesicles in a single-step yielding sufficient quantities
SCFs&T FOR NEw MATERIALS AND MATERIALS PROCESSING 63
for clinical research becoming, thereby, nanocarriers to be
used in nanomedicine for drug delivery purposes. A cou-
ple of examples of novel nanomedicines prepared by this
methodology will be presented and their advantages dis-
cussed [11,12].
REFERENCES
[1] M. E. Davis, Z. Chen, D. M. Shin, Nature Reviews-Drug Discovery, 7
(2008) 771-782.
[2] P. Couvreur, C. Vauthier, Pharmaceutical Research, 23 (2006) 1417-1450.
[3] D. Peer, J. M. Karp, S. Hong, O. C. Farokhzad, R. Margalit, R. Langer,
Nature Nanotechnology, 2 (2007) 751-760.
[4] E. Reverchon, R. Adami, J. Supercritical Fluids, 37 (2006) 1-22.
[5] K. Mishima, Advanced Drug Delivery Reviews, 60 (2008) 411-432.
[6] M. Cano-Sarabia, N. Ventosa, S. Sala, C. Patiño, R. Arranz, J. Veciana,
Langmuir, 24 (2008) 2433-2437.
[7] E. Elizondo, S. Sala, E. Imbuluzqueta, D. González, M. J. Blanco-Prie-
to, C. Gamazo, N. Ventosa, J. Veciana, Pharmaceutical Research, 28
(2011) 309-321.
[8] E. Moreno-Calvo, M. Muntó, K. Wurst, N. Ventosa, N. Masciocchi, J.
Veciana, Molecular Pharmacology, 8 (2011) 395-404.
[9] S. Sala, A. Córdoba, E. Moreno-Calvo, E. Elizondo, M. Muntó, P. Rojas,
Mª A. Larrayoz, N. Ventosa, J. Veciana, Crystal Growth Design, 12 (2012)
1717-1726.
[10] E. Elizondo, J. Larsen, N. Hatzakis, I. Cabrera, J. Ingrid, J. Veciana, D.
Stamou, N. Ventosa, J. American Chemical Society, 134 (2012) 1918-
1921.
[11] N. Ventosa, L. Ferrer-Tasies, E. Moreno-Calvo, M. Cano, M. Aguilella-
Arzo, A. Angelova, S. Lesieur, S. Ricart, J. Faraudo, J. Veciana, Lang-
muir, 29 (2013) 6519-6528.
[12] I. Cabrera, E. Elizondo, E. Olga; J. Corchero, M. Mergarejo, D. Pulido,
A. Cordoba, E. Moreno-Calvo, U. Unzueta, E. Vazquez, I. Abasolo, S.
Schwartz, A. Villaverde, F. Albericio, M. Royo, M. Garcia-Parajo, N.
Ventosa, J. Veciana, Nano Letters, 13 (2013) 3766-3774.
hyPOLIPEMIANT, ANTI-OBESITy AND ANTITUMOR ACTIVITIES OF SUPERCRITICAL ExTRACTS
65
hyPOLIPEMIANT, ANTI-OBESITy AND ANTITUMOR ACTIVITIES OF SUPERCRITICAL ExTRACTS
sandra R. s. ferreiraDepartment of Chemical and Food Engineering,
Federal University of Santa Catarina (UFSC), EQA/CTC; CP 476 – Trindade, 88040-900, Florianópolis, SC, Brazil;
E-mail: [email protected]
Natural products are a large source of components with
biological activities. Those substances normally present
high aggregated value and are important for different ar-
eas such as medicinal, food and nutritional supplements.
On the other hand, obesity is a serious public health prob-
lem and is an important risk factor associated with the
increase of cardiovascular disease, diabetes, chronic kid-
ney disease, and some types of cancers. Overweight and
obesity are associated with different conditions including
hypertriglyceridemia and hypercholesterolemia which are
caused by a disorder in the lipid metabolism and promote
modifications in serum lipoprotein. Efforts towards the
development of new effective drugs led to the discovery
of hypolipidemic therapeutic agents from natural sources,
which also raise interest for cancer treatment, because
the therapies available are not completely able to reduce the
disease progression and/or present high toxicity. Further-
more, hypolipidemic or antihyperlipidemic agents are a
diverse category of pharmaceuticals that are used for treat-
ment of hyperlipidemia, which means an excess of cho-
lesterol, triglycerides and glucose levels.
In the present work different extracts from natural
products were evaluated for their hypolipemiant, anti-obe-
66 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
sity and antitumor abilities and the raw materials tested
to provide the extracts varied from marine wildlife sourc-
es (pink shrimp residue) to medicinal plants (Cordia ver-
benacea and Casearia sylvestris). There are several usual
procedures to obtain the extracts with biological active
compounds from natural sources, such as low pressure
(LP) methods and also supercritical (SC) technology. These
procedures present advantages and disadvantages, and
the effectiveness of each technique depends on the prod-
uct quality and application, allied with the economical
viability of the process. The anti-obesity and the hypolip-
idemic effects of the extracts (from pink shrimp residue
and from C. sylvestris) were evaluated in vivo by means
of submitting mice species (Swiss Mus musculus normal,
Balb C and knocaut) to different assays. The anti-obesity
characteristic was observed by treating the mice with a
high-fat diet combined with the administration of the nat-
ural product extracts (from LP and SC processes) by oral
gavage doses during 30 days. All animal procedures were
conducted in accordance with legal requirements appro-
priate to the species and approved by local ethics com-
mittee. The weight of the animals during the treatment
and the final total serum cholesterol, triglycerides and
glucose levels were also monitored by means of mice blood
analysis after the high fat diet treatment. The results in-
dicated that the diet using SC extracts from shrimp residue
at 50-100 mg/kg.d showed the best anti-obesity effect for
knocaut and for normal mice, compared to LP extracts.
The same behavior was performed by SC extracts from C.
sylvestris, which presented the lowest mice body weight
gain (best anti-obesity performance). Additionally, the nor-
mal mice group presented lower triglycerides and choles-
terol levels, compared to knocaut when the shrimp residue
extracts were applied. The best efficiency on triglycerides
reduction observed from mice group treated with SC shrimp
SCFs&T FOR NEw MATERIALS AND MATERIALS PROCESSING 67
extract was probably due to a synergistic action of astax-
anthin, eicosapentaenoic (EPA) and docosahexanoic (DHA)
fatty acids present in the extract. Additionally, highest
glucose and triglycerides reductions were observed in an-
imals treated with SC extracts from C. sylvestris, compared
to the mice group treated with LP extract. Medicinal plants,
such as C. verbenacea and C. sylvestris, have multiple
popular uses in Brazil and other American countries, and
are indicated for tumor treatment. In this study, SC extracts
and LP extracts from both plants were tested to evaluate
cytotoxic, antiproliferative, antitumor, nucleasic, antian-
giogenic and apoptotic activities using experimental mod-
els in vitro and in vivo. To achieve this goal, experiments
were performed evaluating the cytotoxic activity (MTT) in
vitro by the viability of MCF-7 (breast cancer) cells and
T-24 (urinary bladder carcinoma) cells. Besides, the effect
of extracts on plasmid DNA through the nuclease activity
was also evaluated. The in vivo antitumor activity was
performed in Balb/C mice inoculated with ascitic Ehrlich
tumor (AET) treated with the extracts at different concen-
trations and through the antiangiogenic activity of Gallus
domesticus eggs fertilized by the chorioallantoic mem-
brane essay (CAM) at concentrations of 1, 5 and 10 mg/
kg/day. The proapoptotic ability was also evaluated by
annexin V essay using flow cytometry in AET cells taken
from mice after extracts treatment. The results for SC ex-
tracts of C. Sylvestris reduced significantly the viability of
MCF-7 and T-24 cells. Regarding the nuclease activity
assessment, the SC extract showed a direct dose-depen-
dent damage on DNA. The in vivo assays demonstrated
that SC extracts of C. Sylvestris provided considerable
antitumor activity. The extracts treatment caused signif-
icant inhibition of tumor growth in mice, causing increase
in the average percentage of mice longevity (PAL). The an-
nexin V essay revealed that the induced cell death by
68 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
C. Sylvestris SC extracts was either by apoptosis or by
necrosis. The SC extracts of C. Sylvestris also presented
antiangiogenic activity by reducing significantly the per-
centage of blood vessels around the embryo.
The results for SC extract of C. verbenacea provid-
ed a significant improvement in the cytotoxity effect for
MCF-7 and EAC cells, and this high cytotoxity potential
of the SC extract is due to the presence of α-humulene
and trans-caryophyllene, which presents anti-inflamma-
tory activity. C. verbenacea SC extract showed higher pro-
apoptotic efficiency, by increasing 15% of unviable cells
compared to LP extract. Interestingly, in none of the treat-
ments the presence of necrotic cells was observed, sug-
gesting a specificity of the treatment effect. One possible
mechanism for the antitumor effect of SC extract of C.
verbenacea can be attributed to the property of inhibiting
COX-2 (ciclooxigenase-2 expression), which can activate
the apoptosis of tumor cells, preventing their proliferation.
Also, both C. verbenacea extracts (SC and LP) showed a
high potential for inhibition of tumor growth in mice com-
pared with the negative control, however the SC extract
presented the best performance.
Additionally, the best results obtained by the SC
extract from C. verbenacea suggest that the cytotoxicity,
as well as the antiproliferative, pro-apoptotic and antitu-
mor activities could be attributable to the high content of
α-humulene and trans-caryophyllene. The approach to
evaluate the medicinal ability of natural extracts, described
here by hypolipemiant, anti-obesity and antitumor activ-
ities, is important to reinforce the supercritical technology
as a relevant process alternative to obtain valuable sub-
stances. The high-quality behavior described by the su-
percritical extracts emphasizes the need to continually
open the areas of application of the supercritical fluids.
OVERVIEW/PLENARy LECTURES ON ThE ROLE OF SUPERCRITICAL FLUIDS AND TEChNOLOGy (SCFs&T)
SCFs&T for Green Chemistry and Sustainable Technology
NEw DEVELOPMENTS AND RESEARCh IN CO2 CAPTURING
71
NEw DEVELOPMENTS AND RESEARCh IN CO2 CAPTURING
María francisco, Adriaan van den Bruinhorst, Lawien f. Zubeir, cor J. peters*, Maaike c. Kroon
Department of Chemical Engineering and Chemistry, Separation Technology Group,
Eindhoven University of Technology; Den Dolech 2, 5612 AZ Eindhoven, Netherlands;
E-mail: [email protected] *The Petroleum Institute,
Chemical Engineering Department;P.O. Box 2533, Abu Dhabi, U.A.E.;
E-mail: [email protected]
Over the past years, the increasing concern about global
warming encouraged the scientific community to search
and develop “zero emission” processes [1]. In this context,
the reduction of carbon dioxide (CO2) release to the atmo-
sphere became one of the most challenging research in-
terests, because CO2 is considered to be the major cause
of the greenhouse phenomenon.
The removal of CO2 from natural gas or the captur-
ing of CO2 from flue gas, produced by post-combustion
industries, became a big challenge due to the large vol-
umes of CO2 and often the low CO
2 concentration in the
source gases. Most of the commercial absorption process-
es for CO2 use different types of alkanolamine solvents such
as monoethanolamine (MEA), diethanolamine (DEA) or
N-methyldiethanolamine (MDEA) [2]. Despite their good
performance as solvents for chemical absorption, amine
technologies show several important drawbacks in terms
of operational cost, solvent regeneration and the suscep-
tibility of amines to undergo thermal or oxidative degra-
dation. The emissions of amines and degradation products
72 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
to the atmosphere can cause serious damage to the envi-
ronment as well as human health [3]. For this reason, the
study of properties like their volatility became a very im-
portant issue for any work on solvent design in this area [4].
Three main approaches were found towards the de-
velopment of new “green” solvents in carbon capture [5]:
a) The use of safer solvents for health and environ-
ment, e.g., solvents showing high biodegradability;
b) The use of so-called “bio-solvents” produced from
readily available renewable resources;
c) The substitution of volatile organic solvents by less
volatile ones such as ionic liquids (ILs) with negli-
gible vapor pressure and, so far, with no detectable
emissions into the atmosphere.
ILs attracted particular attention over the past years
because they can be designed by choosing the cation-an-
ion combination to pursuit the best performance as sol-
vents for a certain application [6]. Together with their, in
general, extremely low volatility, the so-called “Task Spe-
cific Ionic Liquids” show promising advantages for CO2
capture compared to the conventional solvents. Examples
include the more suitable physico-chemical properties and
the higher degree of control of the solubility of gases in the
IL. However, the “green” character of ILs can be questioned
because most of them are produced from fossil resources
and their synthesis cannot be considered as being “green”.
Moreover, the high production and purification cost do not
make ILs technology competitive with traditional solvents
[7,8].
To overcome some of the limitations of ILs, Deep
Eutectic Solvents (DES) were revealed by Abbott as ver-
satile alternatives [9]. These low transition temperature
SCFs&T FOR GREEN ChEMISTRy AND SUSTAINABLE TEChNOLOGy 73
mixtures (LTTMs) consist of at least one hydrogen bond
donor (HBD) and one hydrogen bond acceptor (HBA) coun-
terpart resulting in the formation of a liquid mixture show-
ing an unusual low freezing point. Due to the high hydrogen
bonding interaction, some of the promising characteristics
of ILs as solvents are shared by DESs. They often possess
an extremely low volatility, and their properties can be
adjusted by selecting the nature and ratio of the hydrogen
bonding pairs. They can also be designed to show a wide
liquid range, water-compatibility, non-flammability, non-
toxicity, biocompatibility or biodegradability. Finally, they
can be easily prepared from readily available starting ma-
terials and becoming a competitive solvent in terms of
cost.
The first DES reported by Abbott [10] was formed
by mixing urea with choline chloride. Since then, other
similar DESs were prepared [11,12] and applied to differ-
ent purposes as solvents or catalysts in reactions or bio-
transformations [13], liquid separations [14] and metal
electro-deposition [15]. Not much is known about these
liquid mixtures; only the firstly reported one was very well
characterized and studied. Taking advantage of the abil-
ity to tailor the phase behavior and physical properties of
DES, studies on new combinations of hydrogen bond donor:
acceptor have to be explored for the optimization of their
performance as solvents for a certain application. The ef-
fect of different variables on their physical properties like
temperature, water content or composition need to be in-
vestigated, as well as the thermodynamic parameters gov-
erning their phase behavior. To the best of our knowledge,
the only DES explored for CO2 capture and reported in
literature is also the choline chloride + urea mixture [16].
In the search for eco-friendly and bio-renewable
solvents, new mixtures have been investigated in this study.
74 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
For that purpose, a new combination of choline chloride
with a natural organic acid is studied. The choline cation
was already explored for CO2 capture forming part of so-
called “natural ionic liquids” [17], but never in a combina-
tion with an organic acid. The choline chloride salt presents
the advantage over choline-based ILs of being a readily
available starting material as it is considered as one of the
essential nutrients in nature. The chosen organic acid is
lactic acid, a natural carboxylic acid present in milk and
vegetables, which can be easily produced by fermentation
of carbohydrates [18]. The new type of low transition tem-
perature mixtures in this work are formed by mixing both
starting materials, i.e. choline chloride and lactic acid, in
different ratios. A complete study on physical properties
like density, viscosity, surface tension, and glass transition
temperature has been executed in this work. In addition,
the CO2 solubility in these liquid mixtures is studied to
explore their suitability for CO2 capturing.
An important parameter of a solvent for capturing
CO2 is the loading capacity of the solvent. However, a pa-
rameter equally important is the rate of dissolution of the
gas in the solvent. In case the absorption rate is low, this
will lead to quite large absorption facilities. In order to
influence the kinetics of the absorption process, another
aspect of this research comprises the application of high-
gravity (HiGee) forces to reach thermodynamic equilibrium
in a relatively short time, leading to much smaller sepa-
ration units, which even can become mobile [19].
REFERENCES
[1] P. T. Anastas, M. M. Kirchhoff, Accounts of Chemical Research, 35
(2002) 686.
[2] N. MacDowell, N. Florin, A. Buchard, J. Hallett, A. Galindo, G. Jackson,
C. S. Adjiman, C. K. Williams, N. Shah, P. Fennell, Energy Environmen-
tal Science, 3 (2010) 1645.
SCFs&T FOR GREEN ChEMISTRy AND SUSTAINABLE TEChNOLOGy 75
[3] J. J. Renard, S. E. Calidonna, M. V. Henley, J. Hazardous Materials,
108 (2004) 29.
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chemical Engineering Quaterly, 23 (2009) 207211.
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Environmental Science (2012).
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American Chemical Society, 126 (2004) 9142.
[10] A. P. Abbott, G. Capper, D. L. Davies, R. K. Rasheed, V. Tambyrajah,
Chemical Communications, 70 (2003).
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E. Arends, G. J. Witkamp, R. Verpoorte, Plant Physiology, 156 (2011)
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COMBINING IONIC LIqUIDS AND COMPRESSED GASES FOR SUSTAINABLE PROCESS AND ENERGy ENGINEERING APPLICATIONS
77
COMBINING IONIC LIqUIDS AND COMPRESSED GASES FOR SUSTAINABLE PROCESS AND ENERGy ENGINEERING APPLICATIONS
Aaron M. scurtoDepartment of Chemical & Petroleum Engineering,
University of Kansas; 1530 W. 15th St., 4132 Learned Hall, 66045, Lawrence, KS, USA;
E-mail: [email protected]
Ionic liquids (ILs) are experiencing intense research focus
due to their molecular flexibility producing a wide range
of properties useful as solvents and functional materials.
While their human and environmental impacts vary widely,
their exceedingly-low volatility eliminates fugitive emis-
sions which is one of the largest forms of industrial solvent-
based pollution. Combining compressed or supercritical
gases with ionic liquids has a number of beneficial effects
for reactions, separations, and energy applications. Ionic
liquids are insoluble in the majority of compressed gases
except for the most polar gases at high pressures. More-
over, these processes may have lower human and envi-
ronmental impact than some conventional processes. Here,
several of our group’s projects ranging from organic and
homogeneous catalyzed reactions, to separations, novel
absorption refrigeration, and novel Rankine/Power cycles,
etc. will be overviewed. The synthesis of ionic liquids
themselves in supercritical (SCF) or CO2-expanded solvents
(CXLs) have been investigated and shown to have a num-
ber of processing advantages over conventional solvents
especially the possibility to combine reaction and sepa-
ration. Ionic liquids have negligible solubility in com-
pressed CO2 while the reactants can be made miscible/
critical with CO2. CO
2-expanded reaction mixtures also
have control over reaction and separation with interme-
78 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
diate vapor-liquid-liquid equilibrium. Other CXLs using
polar aprotic solvents such as DMSO can be leveraged to
provide high kinetic rates and easy separation. When com-
paring the complete life-cycle analyses of IL synthesis,
both SCF and CXLs have advantages over conventional
liquid processes. Biphasic Systems with Ionic liquids and
compressed CO2 can provide an interesting platform for
reactions and separations involving such homogeneous-
ly-catalyzed reactions as hydrogenation and hydroformy-
lation. Here, the ionic liquid acts as a support phase for
the soluble catalyst and the temperature and pressure of
the compressed CO2 phase affects the partitioning of re-
actants and products and increases the mass transfer rates
into the IL phase. Alternatively, the ionic liquid may be
able to provide advantages in the post-processing of re-
action or extraction processes that use supercritical or
CO2-expanded liquids. The temperature, pressure, and
amount of the ionic liquid may be used to induce phase
behavior such as vapor-liquid-liquid or vapor-liquid equi-
librium. The ability to tune the phase behavior of ILs and
compressed gases to prevent IL from entering the com-
pressed gas phase yields itself for engineering applications
in refrigeration and power production. Here, the ionic liq-
uid first absorbs a gas at a relatively low temperature and
pressure, after which the solution is pumped to high pres-
sures. Lower quality (temperature) waste heat can be
used to liberate the dissolved gas producing a stream of
high-pressure-high-temperature gas. This stream may then
be used for two different types of energy applications. If
the stream is then cooled and liquefied, it may be then
sent through an expansion valve and heat exchanger to
provide a cooling effect in novel type of absorption refrig-
eration. Regardless of the application, knowledge of chem-
istry, kinetics, thermodynamics, and transport phenomena
are all required to optimize these systems.
PERSPECTIVES ON ThE USE OF SUPERCRITICAL FLUIDS IN REFRIGERATION CyCLES
79
PERSPECTIVES ON ThE USE OF SUPERCRITICAL FLUIDS IN REFRIGERATION CyCLES
gustavo BolañosSchool of Chemical Engineering,
Universidad del Valle; Cali, Colombia;
E-mail: [email protected]
During the last years, there has been a lot of interest in
replacing the working fluids that are currently used in re-
frigeration cycles, by fluids that at the same time have low
Ozone Depletion Potential (ODP), and low Global Warming
Potential (GWP). ODP is defined as the capacity of a sub-
stance to react with the atmospheric ozone as compared
to that of trichlorofluoromethane (R11), and GWP is defined
as the global warming capability of a substance as com-
pared to that of the same amount of carbon dioxide during
a determined time span. Many of the refrigerants that are
currently in use were introduced for replacing chlorofluo-
rocarbons that were phased-out by the Montreal protocol
because of their high ODP. Unfortunately, despite their low
ODP, the replacing refrigerants have a high GWP. For ex-
ample, the ODP of R134a, a widely used refrigerant, is zero,
but its GWP is 1300.
Because reducing emissions of greenhouse gases
has been accepted worldwide as part of the effort to mit-
igate the climatic change, there is a need for new refrig-
erants with low ODP and GWP. Many synthetic refrigerants
that have been recently developed have a GWP close to
150, and only few have lower GWP. However, the manu-
facture of these compounds is difficult because they have
80 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
many isomers and thus the separation processes involved
increase the cost of such substances. In addition, in some
cases there is no knowledge on the final fate or on the mean
lifetime of these compounds once released into the envi-
ronment.
In this context, the use of carbon dioxide as a work-
ing fluid both for subcritical and transcritical refrigeration
cycles has gained a lot of attention. Historically, carbon
dioxide was in fact one of the first refrigerants that were
considered, and was used in commercial air conditioning
systems until 1932, when chlorofluorocarbons were intro-
duced. In those days, the limited technological capabilities
for handling pressures above the critical pressure of carbon
dioxide did not favor the use of this substance. Those lim-
itations do not exist today. The interest in supercritical car-
bon dioxide as a working fluid was renewed in 1990, when
several patents on transcritical cycles were awarded.
Carbon dioxide presents favorable values of ODP and
GWP (0 and 1, respectively). Its thermodynamic properties
are such that they produce a high coefficient of perfor-
mance, high compression efficiencies, and high volumet-
ric refrigeration capacities (1.6 times that of ammonia, 5
times that of R22, and up to 8 times that of R12). Its high
thermal conductivity and low viscosity, in particular in the
supercritical region, make this substance an excellent heat
transfer fluid. As a result, the size of carbon-dioxide-based
refrigeration units is smaller than those of conventional
ones, making it suitable even for mobile applications such
as automotive air conditioning. In addition, as it is well
known, carbon dioxide is not toxic, flammable or corrosive
(if no water is present). As a refrigerant, it is designated
as R744.
Several challenges have to be faced before massive
introduction of refrigeration systems based on supercriti-
SCFs&T FOR GREEN ChEMISTRy AND SUSTAINABLE TEChNOLOGy 81
cal carbon dioxide can be accomplished. Some of them
are technical, and some are non-technical. The technical
challenges are related to the need on information about
how the presence of lubricating oils that are used in in-
stallations based on the vapor compression cycle affects
the performance of the cycle. Lubricant oil is needed in the
compressor for preventing mechanical wearing of the pis-
tons and other parts, for reducing noise, and for sealing
and cooling the compressor. Phase equilibrium for mixtures
of lubricating oils and carbon dioxide is thus an important
issue that has been addressed in different publications,
as well as how the concentration of lubricant oil in the
carbon-dioxide-rich phase affects the thermodynamic and
transport properties of the fluid, and how the carbon di-
oxide dissolved in the lubricating oil affects its viscosity
and the performance of the system during its dynamic
behavior. Several works have been dedicated to measure-
ment, correlation and estimation of these properties for
engineering purposes.
Simulations considering pure carbon dioxide have
shown that there is a pressure at the exit of the compres-
sor that maximizes the coefficient of performance (COP),
and that an optimum pressure exists for a given outlet
temperature of the gas cooler. Correlations have been de-
veloped for optimum pressure, system COP and optimal
gas cooler inlet temperature. Different cycle configurations
have also been analyzed, such as the use of an internal
heat exchanger, the use of two-stage compression with
and without economizer, and the use of expanders for tak-
ing advantage of the work produced during expansion.
The objective of these studies was to find a configuration
that maximizes the cycle COP. At present, many papers
have been published on the heat transfer mechanisms and
pressure drop correlations of carbon dioxide during boiling
82 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
and cooling, in order to provide a theoretical basis for de-
signing efficient components of refrigeration cycles. In this
presentation, the main aspects of these topics will be re-
viewed.
The use of supercritical fluids as working fluids in
refrigeration cycles shows a high promise for commercial
application in a short time. Several large companies are
already committed to replacing conventional refrigeration
systems by supercritical-carbon-dioxide-based systems,
and the business opportunities in this field are growing
very fast.
OVERVIEW/PLENARy LECTURES ON ThE ROLE OF SUPERCRITICAL FLUIDS AND TEChNOLOGy (SCFs&T)
SCFs as Working Fluids and Process Technology
SPECIFICS OF ThERMOPhySICAL PROPERTIES AND hEAT TRANSFER AT SUPERCRITICAL PRESSURES
85
SPECIFICS OF ThERMOPhySICAL PROPERTIES AND hEAT TRANSFER AT SUPERCRITICAL PRESSURES
igor pioroFaculty of Energy Systems and Nuclear Science,
Institute of Technology, University of Ontario;
2000 Simcoe Street North, Oshawa, Ontario L1H 7K4, Canada; E-mail: [email protected]
It is well known that the electrical-power generation is
the key factor for advances in any other industries, agri-
culture and level of living. In general, electrical energy
can be generated by non-renewable-energy sources such
as coal, natural gas, oil, and nuclear; and renewable- energy
sources such as hydro, wind, solar, biomass, geothermal
and marine. However, the main sources for electrical-energy
generation are a) thermal — primary coal and secondary
natural gas; b) “large” hydro and c) nuclear. The rest of
the energy sources might have visible impact just in some
countries. In addition, the renewable-energy sources, for
example, such as wind and solar and some others, are not
really reliable energy sources for industrial-power gener-
ation, because they depend on Mother Nature and relative
costs of electrical energy generated by these and some
other renewable-energy sources with exception of large
hydro-electric power plants can be significantly higher
than those generated by non-renewable sources.
For a sustainable and efficient power industry, ther-
mal and nuclear power plants should be used as a basis
for the electrical-energy generation, and these plants should
use high-temperature and high-pressure working fluids
including supercritical fluids. Therefore, specifics of heat
86 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
transfer and thermophysical properties of supercritical
fluids are very important for reliability and safety of new
power plants.
The use of Supercritical fluids (SCFs) in different
processes is not new, and nor was it a human invention.
Mother Nature has been processing minerals in aqueous
solutions at near or above the critical point of water for
billions of years. It was only in the late 1800’s when scien-
tists started to use this natural process, called hydrother-
mal processing, in their labs for creating various crystals.
During the last 50-60 years, this process (operating pa-
rameters - water pressures from 20 to 200 MPa and tem-
peratures from 300 to 500 ºC) has been widely used in the
industrial production of high-quality single crystals (main-
ly gem stones).
First works devoted to the problem of heat transfer
(HT) at Supercritical pressures (SCPs) started as early as
the 1930s. Schmidt et al. investigated free-convection HT
of fluids at the near-critical point with the application to
a new effective cooling system for turbine blades in jet
engines.
In the 1950s, the idea of using Supercritical water
(SCW) appeared to be rather attractive for steam genera-
tors/turbines in the thermal-power industry. The objective
was to increase the total thermal efficiency of coal-fired
power plants. At SCPs there is no liquid-vapour phase tran-
sition; therefore, there is no such phenomenon as critical
heat flux or dryout. It is only within a certain range of
parameters that deteriorated HT may occur. Therefore, the
objective of this paper is a discussion on specifics of ther-
mophysical properties and HT of SCFs in power-engineer-
ing applications.
As a result of our studies into SCFs several heat-
transfer correlations have been developed for SCW flowing
SCFs AS WORKING FLUIDS AND PROCESS TEChNOLOGy 87
upward in vertical bare tubes. The correlation based on
the bulk-fluid-temperature approach appeared to be the
most accurate one compared to other well-known 16 cor-
relations. The proposed correlation has an uncertainty of
±25% for heat-transfer-coefficient values and about ±15%
for calculated wall temperatures and is valid within the
following range: Pressures 22.8-29.4 MPa, heat fluxes
70-1250 kW/m2, mass fluxes 200-1500 kg/m2s, and tube
inside diameters 3-28 mm.
However, the developed SCW correlation has less
accuracy when applied to SC carbon-dioxide data. There-
fore, a new correlation based on the wall-temperature ap-
proach was developed. This correlation has an uncertainty
of ±30% for HTC values and about ±20% for calculated
wall temperatures and is valid within the following range:
Pressures 7.6-8.8 MPa, heat fluxes 9.3-617 kW/m2, mass
fluxes 706-3170 kg/m2s, and tube inside diameter 8 mm.
SUPERCRITICAL CARBON DIOxIDE FOR USE IN ADVANCED POwER CyCLES FOR hIGh TEMPERATURE SOLAR, NUCLEAR AND FOSSIL ENERGy
89
SUPERCRITICAL CARBON DIOxIDE FOR USE IN ADVANCED POwER CyCLES FOR hIGh TEMPERATURE SOLAR, NUCLEAR AND FOSSIL ENERGy
Mark AndersonUniversity of Wisconsin-Madison;
1500 Engineering Dr. Madison WI, 53706, USA; E-mail: [email protected]
The importance of improved efficiency, reduced capital
cost and higher operational temperature of future power
production has led to renewed interest in studying ad-
vanced Brayton cycles utilizing supercritical carbon di-
oxide as the working fluid for high temperature energy
conversion. Previous work conducted by Dostal et al. [1]
has shown that the supercritical CO2 recompression cycle
proposed by Feher [2] may be superior to other advanced
high temperature cycles both from the standpoint of in-
creased thermal efficiency as well as reduced size and
cost of the required turbo-machinery components. These
advantages make the cycle especially well-suited for any
high temperature reactor system including the Sodium-
Cooled Fast Reactor (SFR), the Fluoride Salt-Cooled High
Temperature Reactor (FHR), the Lead-Cooled Fast Reactor
(LFR) and the Very High Temperature Reactor (VHTR). The
cycle is also of interest for use in Concentrating Solar Power
(CSP) systems and has recently become of interest for use
in fossil fuel power production to aid in CO2 reduction and
sequestration. Sandia national laboratories [3] has begun
testing supercritical CO2 compressors and turbines fabri-
cated by Barber Nichols Inc. and has found promising
initial results. Argonne national laboratory has analyzed
several configurations coupled to advanced reactor de-
90 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
signs and conducted initial studies on commercial PCHEs
(Printed Channel Heat Exchangers) fabricated by Heatric.
NREL along with several commercial partners has lead
an effort to study the cycles performance for solar appli-
cations and is leading a US. Department of Energy effort
to develop a 10MW s-CO2 turbine system for demonstra-
tion and future scale up.
In order to realize these goals and demonstrate the
applicability of this cycle several key fundamental phe-
nomena need to be further understood. As an effort to
advance this technology the University of Wisconsin is
conducting research in the following different areas:
� Highly instrumented heat transfer and pressure
drop experiments on Printed circuit heat exchang-
ers (PCHE) geometries near the critical point that
can be analyzed with both 1D models and with more
complex 3D CFD models. Based on the analysis of
the experiments and the detailed CFD calculations,
improvements to the models currently used in plant
dynamics code calculations are being achieved and
optimization of heat exchanger passages for s-CO2
are being developed.
� Development and implement of optimized fluid prop-
erty algorithms within the Plant Dynamics Code
and CFD codes to increase the calculation accura-
cy and reduce computational costs. One of the ma-
jor issues with calculations of supercritical fluids is
the use of highly accurate thermal physical proper-
ty data, while this data is available through programs
such as REFPROP it is computationally expensive
to call at each itteration. Development of advanced
lookup tables using bi-cubic spline methods can
help to reduce the computational burden and still
maintain the high accuracy required in calculations.
SCFs AS WORKING FLUIDS AND PROCESS TEChNOLOGy 91
� Experiments to investigate the critical flow of the
supercritical fluid through shaft seals and valve
components. If a fluid is near the pseudo critical
point or approaches and enters the two phase dome
the assumptions of homogenous equilibrium flow
may not hold. Research is currently underway to
determine the discharge coefficient and critical
mass flow rate for supercritical carbon dioxide at
these conditions.
� S-CO2 can be a highly oxidizing/corrosive fluid and
if it is to be used as the working fluid in power plants
with intended lifetimes of up to 40 year it is neces-
sary to investigate the corrosion mechanisms on
alloys. Corrosion coupled with the high tempera-
tures and pressures of the cycle make the selection
of appropriate materials a key area of research.
This talk will give a quick overview of some of the
above research and how it relates to the future develop-
ment of advanced s-CO2 Brayton power cycles. It will also
elucidate the interesting phenomena associated with su-
percritical fluids.
REFERENCES
[1] V. E. A. Dostal, The supercritical carbon dioxide power cycle: Compa-rision to other advanced power cycles, Nuclear Technology, 154 (2006) 23.
[2] E.G. FEHER, The Supercritical Thermodynamic Power Cycle. In: Doug-las Paper nº 4348, presented to the IECEC. August 12-17, 1967. Miami Beach, Florida, USA.
[3] S. A. Wright, P. Pickard, R. Fuller, Early supercritical CO2 compression loop operation and test results (2008).
[4] A. MOISSEYTSEV et al., Comparison of heat exchanger modeling with data from CO2-to-CO2 printed circuit heat exchanger performance tests. In: International Congress on Advances in Nuclear Power Plants 2010, ICAPP 2010, June 13-17, 2010. San Diego, CA, United States: American Nuclear Society.
92 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
[5] A. Moisseytsev and J. J. Sienicki, Development of the ANL Plant
Dynamics Code and Control Strategies for the Supercritical Carbon
Dioxide Brayton Cycle and Code Validation with Data from the Sandia
Small-Scale Supercritical Carbon Dioxide Brayton Cycle Test Loop,
ANL-ARC-218, 2011, Argonne National Laboratory.
[6] A. Moisseytsev and J. J. Sienicki, Development of a Plant Dynamics
Computer Code for Analysis of a Supercritical Carbon Dioxide Brayton
Cycle Energy Converter Coupled to a Natural Circulation Lead-Cooled
Fast Reactor, ANL-06/27, 2006, Argonne National Laboratory.
[7] G. Cao, V. Firouzdor, K. Sridharan, M. Anderson, and T.R. Allen, Corro-
sion of Alloys in High Temperature Supercritical Carbon-Dioxide, Cor-
rosion Science, 60 (2012) 246.
SUPERCRITICAL CO2 ExTRACTION OF BIOLOGICAL SUBSTRATES: FROM ThE LABORATORy TO ThE INDUSTRIAL APPLICATION
93
SUPERCRITICAL CO2 ExTRACTION OF BIOLOGICAL SUBSTRATES: FROM ThE LABORATORy TO ThE INDUSTRIAL APPLICATION
José M. del valle Departamento de Ingeniería Química y Bioprocesos,
Pontifi cia Universidad Católica de Chile; Avenida Vicuña Mackenna 4860, Macul, Santiago, Chile;
E-mail: [email protected]
Despite extraction of valuable compounds from biological
substrates using supercritical (sc) CO2 as a replacement
of conventional organic solvent has been an industrial
reality for more than three decades, there is reluctance in
adopting this high-pressure technology because of the
wrong perception that scCO2 extraction is not fully com-
petitive. This presentation analyzes economics of scCO2
extraction of vegetable oil from prepressed seeds. This
example can be used as case study because of the avail-
ability of a mathematical model of the extraction process
that can be applied for process simulation purposes. Pre-
pressed oilseeds have an interconnected network of pores
that are filled with part of the oil expelled from fractured
cells during pressing. The shrinking core model hypothe-
sis applies to mass transfer in this substrate having as a
parameter the effective diffusivity (Ed) within the pore
network. Ed relates to a particle-size and scCO2-condition-
independent, and pretreatment dependent microstructur-
al factor. The shrinking core model is partially predictive
in that there are dimensionless correlations proposed in
literature for transport phenomena (film mass transfer, and
axial dispersion) in a packed bed operating with supercrit-
ical fluids, and for the solubility of vegetable oils in scCO2.
94 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
Estimates of extraction cost are anchored in a simulation
program describing the relationship between oil yield and
extraction time in an industrial plant having ≥3 extraction
vessels. A typical cost of about 8 USD/kg oil was estimat-
ed for scCO2 extractions at 40 ºC and 30 MPa. Optimal
mass flow rate of CO2 depends on particle diameter, which
should not be reduced necessarily below 2 mm. Extraction
cost depends little on the length-to-diameter ratio of the
vessels. For a same total volume of extraction vessels,
the cost diminished as the number of vessels increased.
For the same plant productivity, the cost diminished when
increasing extraction pressure above 30 MPa. Economies
of scales reduce cost when plant size increased. Simula-
tion results are not properly accounted for in laboratory
and pilot plan runs using a single extraction vessel.
ExTRACTION OF LIPIDS AND CAROTENOIDS FROM ALGAE By SUB- AND SUPERCRITICAL CO2 AND DIMEThyL EThER
95
ExTRACTION OF LIPIDS AND CAROTENOIDS FROM ALGAE By SUB- AND SUPERCRITICAL CO2 AND DIMEThyL EThER
Motonobu goto, hideki KandaNagoya University;
Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8603, Japan; E-mail: [email protected]
Algae of various species contain valuable organic com-
pounds. Algae are diverse group ranging from unicellular
to multicellular forms. One of these is Undaria pinnatifida,
a brown alga, commonly known as “wakame” in Japan.
This edible seaweed is widely consumed, and has been
part of the diet in many countries, especially Korea and
Japan. Algae possess several functional properties such
as antioxidant, anticancer, antiviral, and antiobesity prop-
erties. They also contain lipids and sulfated cell-wall
polysaccharides such as fucoidans. On the other hand,
microalgae are recently focused as a source of biofuel.
They also contain functional compounds. To extract the
functional compounds and lipids, organic solvent or su-
percritical carbon dioxide have been used. The extraction
process usually requires drying and grinding process. We
have applied supercritical carbon dioxide extraction for
marine algae to recover fucoxanthin and lipids [1]. Then,
we used subcritical water to recover fucoidans [2]. Lardon
et al. [3] conducted a life cycle assessment of algal bio-
diesel production, and indicated that drying and n-hexane
extraction steps consumed huge energy and made algal
fuel production in a negative energy balance. They have,
thus, suggested wet extraction as an alternative method.
Then, we proposed the use of liquefied dimethyl ether
96 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
(DME) as solvent of lipids and hydrocarbons from wet mi-
croalgae containing over 90% water content. The DME
extraction can be used for all microalgae types, e.g., Mi-
crocystis aeruginosa, Botryococcus braunii, and Euglena
gracilis.
SUBCRITICAL DME ExTRACTION
The DME extraction eliminates the need for drying,
cell disruption, and solvent evaporation at high tempera-
ture; hence, it has advantages such as simpler system and
low energy consumption. The proposed extraction uses
DME which is the simplest form of ether and has the fol-
lowing characteristics: (a) high affinity to oily compositions
and partial miscibility with water, (b) low normal boiling
point (-24.8 °C), (c) approval from the European Food Safe-
ty Authority as a safe extraction solvent for the production
of foodstuff and food ingredients, and (d) resistance to
autoxidation unlike other alkyl ethers. Because heats of
seawater (15 °C) and sun-warmed water (45 °C) around
the ambient temperature (30 °C) are converted into ener-
gy for DME extraction by DME sending pump, the total
energy required by the DME extraction is only for DME
sending pump. In other words, the DME extraction is a
novel energy-saving system [4]. Moreover, we have already
developed bench-scale equipment and verified the con-
cept of DME extraction [4,5].
ExPERIMENTAL
For supercritical CO2 extraction, semi-continuous
flow-type apparatus was used. About 5 g of dried pow-
dered sample was loaded in a 10 mL extractor vessel. Dry
sample was milled using IKA-Werke mill and then sieved
using a mesh size of 60. For subcritical water extraction,
batch reactor or semi-continuous flow-type apparatus was
SCFs AS WORKING FLUIDS AND PROCESS TEChNOLOGy 97
used. Electric heater or microwave heating system were used
to heat-up the extractor. For subcritical DME extrac tion,
simplified flow-type apparatus was used. Wet microalgae
(water content were over 80%) were placed in the lower half
of a cylindrical extractor, while glass beads (0.71-0.99 mm
diameter) were placed at the upper half of the extractor. The
extractor was pressure-resistant glass coated with poly-
carbonate. First, liquefied DME was then supplied to the
extractor and the flow rate was adjusted by a back-pressure
regulator. At a predetermined point of temperature and
pressure, liquefied DME was passed through the extractor
at a flow rate of 10 ml/min at 20 °C [6].
RESULTS
1. Supercritical CO2 extraction
The recovered amount of fucoxanthin increased at
low temperature, and high pressure under supercritical
conditions. The maximum percent recovery reached 80%
at 40 °C and 40 MPa. The recovery of fucoxanthin is strong-
ly related to the density of supercritical carbon dioxide
which normally increases with increasing pressure and
decreasing temperature and has a positive correlation with
solvating power. It is expected that the recovery of fucox-
anthin also increased with increasing density of supercrit-
ical CO2, however, at 25 °C, low yield was obtained due
most likely to lower diffusivity of liquid CO2. It is also like-
ly that an increase in temperature above 50 °C might have
caused degradation of fucoxanthin, a thermally labile com-
pound. The use of cosolvent such as ethanol was also re-
ported to improve scCO2 extraction yield of fucoxanthin.
The drawbacks of using such cosolvent, however, include
costly and tedious separation of the solvent from the ex-
tracts and coextraction of some unwanted compounds
such as chlorophyll in the products.
98 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
2. Subcritical DME extraction
Based on extraction yields of the two solvent ex-
traction systems, the DME system was over 97.0% of the
Bligh-Dyer’s system in extraction rate, which suggests that
the yields from the two procedures, which are completely
different, was approximately the same. Also the element
compositions, molecular weight distributions, and GC-MS
spectra of extracts by both extractions are almost the same
(Kanda et al. [7,8]).
ACKNOWLEDGMENTS
A part of this research was supported by Industrial Technology Research Grant Program in 2009 (Project ID: 09B40009c, H. Kanda) from New En-ergy and Industrial Technology Development Organization (NEDO) of Japan.
REFERENCES
[1] A. T. Quitain, T. Kai, M. Sasaki, M. Goto, Supercritical Carbon Dioxide Extraction of Fucoxanthin from Undaria pinnatifida, J. Agricultural and Food Chemistry, 61 (2013a) 5792-5797.
[2] A. T. Quitain, T. Kai, M. Sasaki, M. Goto, Microwave-Hydrothermal Ex-traction and Degradation of Fucoidan from Supercritical Carbon Di-oxide Deoiled Undaria pinnatifida, Industrial & Engineering Chemistry Research, 52 (2013b) 7940-7946.
[3] L. Lardon, A. Hélias, B. Sialve, J-P. Steyer and O. Bernard, Life-cycle assessment of biodiesel production from microalgae, Environmental Science & Technology, 43 (2009) 6475-6481.
[4] H. Kanda, Super-energy-saving dewatering method for high-specific- surface-area fuels by using dimethyl ether, Adsorption Science & Tech-nology, 26(5) (2008) 345-349.
[5] H. Kanda and H. Makino, Energy-efficient coal dewatering using liq-uefied dimethyl ether, Fuel, 89 (2010) 2104-2109.
[6] H. Kanda and P. Li, Simple extraction method of green crude from natural blue-green microalgae by dimethyl ether, Fuel, 90 (2011) 1264-1266.
[7] H. Kanda, P. Li, T. Ikehara and M. Yasumoto-Hirose, Lipids extracted from several species of natural blue-green microalgae by dimethyl ether: extraction yield and properties, Fuel, 95 (2012) 88-92.
[8] H. Kanda, P. Li, T. Yoshimura and S. Okada, Wet extraction of hydrocar-bons from Botryococcus braunii by dimethyl ether as compared with dry extraction by hexane, Fuel, 105 (2013) 535-539.
MATERIALS PROCESSING By SUPERCRITICAL CARBON DIOxIDE POwDERIzATION, IMPREGNATION — AChIEVEMENTS AND ChALLENGES
99
MATERIALS PROCESSING By SUPERCRITICAL CARBON DIOxIDE POwDERIzATION, IMPREGNATION — AChIEVEMENTS AND ChALLENGES
Eckhard WeidnerRuhr University;
Universitaetsstr. 150 IB6/126, D-44780, Bochum, North-Rhine Westfalia, Germany;
E-mail: [email protected]
The specific and unique properties of carbon dioxide are
offering new pathways to materials with new properties
by processes with considerable savings of energy and oth-
er resources.
Particle generation by supercritical technologies
was a major field of research and development in the past
three decades, resulting in hundreds of publications and
patents and some industrial applications. Processes like
CO2-assisted spray generation, spray drying, spray freez-
ing, spray agglomeration, spraying of melts, precipitation/
crystallization from supercritical solutions are well under-
stood. CO2 may act as solvent or antisolvent, lower melting
points, is reducing viscosities and/or interfacial tension,
helps mechanically to form fine dispersed sprays, acts as
blowing/cooling/freezing media, inertises and allows to
structure particles as needles, micro- or nanofoams, hol-
low spheres or even solid spheres. The particles may also
be deposited on solid substrates, forming a film. Not only
pure substances are modified with respect to particle size
and particle size distribution, but in recent years methods
to generate composites are in the focus of numerous re-
search groups. Processes and formulations for encapsulat-
ing solids, liquids or gases into so-called core-shell systems
have been developed and successfully demonstrated.
100 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
A few products have found their way into the mar-
kets. An example is micronized chocolate which, following
the PGSS-approach (Particles from Gas Saturated Solu-
tions), is produced by mixing molten chocolate with CO2
under pressure, expanding it in a nozzle to generate small
droplets, which are very rapidly crystallizing by reducing
the temperature via the co-expanding CO2. The process
allows generating specific forms of crystals (ß-V) which
together with the small size of the particles (1 to 30 µm)
results in a very unique mouth feeling. The micronized
chocolate is used to manufacture soft ice cream.
Open questions for research are how formation and
stability of dispersions (aerosols, gels, suspensions, emul-
sions, foams and so on) is influenced by supercritical fluids.
Dependencies between the properties of such dispersions
and the form, crystallinity and morphology of precipitating
solid composites have to be investigated experimentally.
Theoretical approaches for modeling phase behavior, com-
positions and transport properties of such complex systems
are required for a knowledge- and science-based approach
for designing materials, tailor-made for specific customer
demands.
A further, but less investigated process for modify-
ing materials is impregnation. Impregnation is defined as
process of imbuing or saturating with something. In tech-
nical applications impregnation is applied for modifying
properties of bulk substances by physically or chemically
binding impregnates to a bulk material or surface. Provid-
ing impregnates in liquid solutes or from a gas phase at
low to moderate pressures is state of the art, connected
with disadvantages like low space yield in case of impreg-
nation from gas phases, slow diffusion processes, long
process times and high amounts of waste water in case
of impregnation from liquid solutions. Prominent examples
SCFs AS WORKING FLUIDS AND PROCESS TEChNOLOGy 101
demonstrate that by applying supercritical fluids and pres-
sure, impregnation time can be reduced, depths of im-
pregnation can be increased and waste water is avoided.
Between around 1990 to 2002 water-free dyeing of
textiles was intensively studied both in the US and Europe.
Although it has been proven in pilot plants that the pro-
cess is ready for commercialization, major developments
have been stopped. After some years of stagnation, Adidas
and Nike have announced in 2012 to produce T-Shirts
which are colored via CO2-dyeing in rather large industri-
al plants, operated in Thailand. It is reported that plants
with dyeing autoclaves in the m³-range are used. Future
has to show whether this is industrial breakthrough for
CO2-assisted dyeing.
A further example is impregnating wood (e.g. as
construction material for windows) with zinc-salts, making
it resistant to water and biological degradation. A large
industrial plant is operated successfully in Denmark since
about 10 years.
Impregnates might either be bound physically or
chemically on the surface or in the bulk of a substrate. In
case of physical sorption the process is mainly controlled
by diffusion and adsorption, while in the second case
chemical reaction rates have to be considered in addition.
By near-critical gas, properties of the substrate, (e.g glass
transition temperature) are modified. Gas induced swell-
ing of the substrate widen diffusion pathways and impreg-
nates dissolved in CO2 may rapidly and deeply penetrate.
Shrinkage of the substrate during expansion might pre-
cipitate and entrap impregnates physically.
Depending on the type of substrate and impregnate
chemical reactions between the two components may take
place in parallel. An example is the impregnation of leath-
er with Chromium or Alumina. Additionally to the above
102 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
described physical effects CO2 is modifying the pH-value
of the tanning solution. The chemical reaction between
chromium and proteins of the skin starts at a pH of about
2,8 and has to be increased to approx. 4 during the im-
pregnation to avoid extensive swelling and destruction of
the hide. It was demonstrated that at CO2-pressures above
3 MPa leather of excellent quality can be achieved after 2
to 3 hours, which is only 15 to 25% of the conventional
time for tanning. As the specific properties of the CO2-pro-
cess allow fine tuning of the pH-value via pressure and
assists the reaction between chromium and proteins, chro-
mium is be dosed in stoichiometric concentration. Thus
the process is free of waste water containing chromium
ions. In parallel more than 90% of the waste-water is avoid-
ed. In a pilot plant with a volume of 1,7 m³ it was demon-
strated that the process is technically and commercially
feasible. The return on investment might be as low as two
years.
Although supercritical assisted impregnation is al-
ready successfully applied in industry, the knowledge of
the underlying physical and chemical principles is limited.
Research and development is done only in a few groups
— additionally the systems are very complex. Understand-
ing the interaction of impregnates (often containing several
chemical species, additives and solvents) with supercrit-
ical fluids as well as the interaction with the substrate is
experimentally, theoretically and intellectually challeng-
ing. As multicomponent — multiphase systems are in-
volved, experiments and analytics are time consuming
and expensive. Theoretical descriptions of phase behav-
ior and transport properties are often not (yet) available.
Nevertheless industrial applications indicate that efforts
in basic research promise to be worthwhile, of high inter-
est and for sure of scientific and probably of commercial
benefit.
PANEL PRESENTATIONS
Panel I: Bio-based fuel processes
LESSONS LEARNED FROM SUPERCRITICAL wATER UPGRADING OF CRUDE OIL — APPLICATION TO BIOMASS LIqUEFACTION AND UPGRADING
105
LESSONS LEARNED FROM SUPERCRITICAL wATER UPGRADING OF CRUDE OIL — APPLICATION TO BIOMASS LIqUEFACTION AND UPGRADING
Michael T. TimkoWorcester Polytechnic Institute;
100 Institute Road, 01609, Worcester, MA, USA; E-mail: [email protected]
hydrothermal liquefaction (HTL) of biomass has many
advantages over other thermochemical biomass technol-
ogies, including superior energy efficiency (especially for
high moisture content resources) and superior bio-oil prod-
uct characteristics. Nonetheless, advances in this field
have been limited due to the challenges associated with
performing experiments and scale-up demonstrations.
Specific challenges include understanding the complex
chemistry associated with biomass feedstocks containing
carbohydrates, lignin, and potentially proteins; difficulties
pumping biomass slurries to HTL pressures at laboratory
and pilot reactor scales; corrosion and precipitation asso-
ciated with the inorganic content of biomass; difficulties
analyzing the complex heat and mass transfer dynamics
associated with HTL processes; catalyst failure due to sul-
fur or nitrogen poisoning. For these reasons, HTL has failed
to live up to its considerable commercial potential. In this
talk, I will examine parallels between HTL and a kindred
technology, supercritical water upgrading (SCWU) of crude
oil. Like HTL, SCWU seeks to use the unique physicochem-
ical properties of water near the critical point to add value
to a carbon-rich resource. Compared to biomass, crude oil
contains far fewer distinct chemical functionalities; is a
liquid at ambient conditions; contains limited inorganic
106 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
components and therefore poses reduced corrosion risk;
demonstrates partial miscibility with SCWU. My talk will
embrace the building SCWU literature, but will focus on
work performed at MIT in the past 4 years. The work at
MIT has combined experimental rate and product mea-
surements with reaction modeling and transport simula-
tion to develop an integrated understanding of the most
important physical and chemical phenomena taking place
during SCWU. The lessons learned from SCWU will then
be used to analyze future directions and opportunities for
HTL.
hIGh PRESSURE IN SyNThETIC FUEL PRODUCTION PAThWAyS
107
hIGh PRESSURE IN SyNThETIC FUEL PRODUCTION PAThWAyS
nicolaus DahmenInstitute of Catalysis Research and Technology,
Karlsruhe Institute of Technology (KIT); Hermann-von-Helmholtz-Platz 1,
76344, Karlsruhe, Baden-Württemberg, Germany;E-mail: [email protected]
high pressure is involved in various processes under de-
velopment to provide renewable energies and materials,
as e.g. in concentrated solar power and fuels as well as in
geothermal energies and carbon dioxide deep site storage.
Also, in the case of biomass utilization pressurized systems
play an important role e.g. in hydrothermal conversion of
wet or thermochemical conversion of dry materials like
e.g. pyrolysis, gasification, gas cleaning and syntheses of
chemicals and fuels. The impact and benefits taken by
application of pressure are manifold. At the example of a
process for synthetic fuels and chemicals production, so-
called second generation biofuels & chemicals, the appli-
cation of pressure in different parts of the process chain
is presented and discussed. Firstly, high pressure gasifi-
cation is introduced. Here, the aim of the elevated pressure
is to produce synthesis gas at pressures adjusted to those
required in the subsequently following chemical synthesis
process avoiding the expensive compression of syngas. In
this case the gasifier is fed with solids and liquids direct-
ly at the desired pressure. Different type of equipment and
technologies can be applied here like extrusion, dense
fluid feeding or feeding of liquids or slurries. In this case,
also gas cleaning has to be performed at the same pressure
108 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
level. To optimize the energetic efficiency, temperature also
has to be adjusted. Therefore a high temperature — high
pressure gas cleaning process is introduced including fil-
tration, sorption of sour gases and carbon dioxide as well
as catalytic decomposition of small organic and nitrogen
containing molecules, otherwise poisoning the chemical
catalysts during synthesis. For Fischer-Tropsch-synthesis
ca. 30 bar are required, for methanol or dimethylehter syn-
thesis pressures of above 60 bar and even above 100 bar.
New reactor designs and operation regimes also have been
explored, like e.g. Fischer-Tropsch synthesis carried out in
micro-structured devices at supercritical conditions. Gas-
ification of biomass usually yields a carbon monoxide to
hydrogen ratio around unity. To adjust this ratio to the spe-
cific synthesis demands, the water gas shift reaction is
also to be facilitated under elevated pressures. For all these
processes, the impact of pressure on the process funda-
mental has to be understood. For several aspects, reliable
data are already available, for others systematic investi-
gations are still required or in progress. For example, in
gasification the fluid dynamics in entrained flow reactors
or the atomization of solid and liquid fuels during injection
are most sensitive to the system pressure. Experiments,
difficult enough in pressurized reaction rooms of tempera-
tures > 1000 ºC, are supported by appropriate modeling.
Here, fluid dynamics have to be coupled with the chemical
reactions occurring in a reasonable way. For application
of elevated pressures, not only the operations conditions
have to be optimized, but also the appropriate choice of
materials, metrological devices, safety protocols has to be
considered. In some cases, pressurized processes compete
to such carried out at ambient conditions. In these cases,
assessment has to be made if the usually higher expense
for pressure vessels and equipment is balanced out by the
PANEL I: BIO-BASED FUEL PROCESSES 109
expected benefits e.g. in regard to process efficiency (ener-
gy), improved yield, or smaller reactor volumes etc. To score
the role of Supercritical Fluid Science and Technology for
new processes in biofuels, an outlook on the emerging
field of biofuels production and implementation is useful.
Biomass is the only renewable carbon resource. On a long
term, it primarily should be used for carbon based fuels
and chemicals production, while heat and electric power
can be provided by all other renewable energies. Thus,
the further exploration, research and development of bio-
mass conversion processes can be expected to attract even
rising attention offering new and exciting fields for research
and development.
BIOMASS-DERIVED SOLID FUEL AS GREEN ENERGy AND ITS SUSTAINABLE USE
111
BIOMASS-DERIVED SOLID FUEL AS GREEN ENERGy AND ITS SUSTAINABLE USE
yoshimitsu uemura, Wissam omar, noridah osman, Ahmad Rajab, suzana yusup
Universiti Teknologi PETRONAS; Bandar Seri Iskandar, 31750, Tronoh, Perak, Malaysia;
E-mail: [email protected]
Biomass is one of the promising renewable sources. Uti-
lizing biomass may be able to mitigate the CO2 emission
and fossil fuel depletion problems. Our research group is
focusing on how to utilize lignocellulosic biomass as green
energy. In this presentation, our recent efforts on torrefac-
tion and its application will be introduced. Torrefaction is
a low temperature treatment for lignocellulosic biomass
at lower temperatures between 200 ºC and 300 ºC under
an inert atmosphere, which has been found to be effective
for improving the quality not only as a solid fuel, such as
energy density and shelf life, but also as a feedstock for
further conversion such as gasification and liquefaction.
Currently, experimental torrefaction studies are mostly on
woody and grass biomass; wood dusts, beech, eucalyptus,
willow, larch, canary grass. We are investigating if this
technology can be applicable to agricultural residues in
Malaysia. The challenge of this technology is to provide
cheap inert atmosphere. We are investigating if flue gas
from boilers can be utilized for the injection gas of torre-
faction. Possible application of the solid fuel produced by
torrefaction will also be proposed.
hIGh PRESSURE WATER REFORMING OF BIOMASS FOR ENERGy AND ChEMICALS
113
hIGh PRESSURE WATER REFORMING OF BIOMASS FOR ENERGy AND ChEMICALS
Ž. Knez, M. Škerget, E. Markočič, M. Knez Hrnčič, M. Ravber
University of Maribor; Slomškovtrg 15, SI-2000, Maribor, Slovenia;
E-mail: [email protected]
The conversion of biomass to biofuels and biobased chem-
icals has attracted a lot of attention recently, largely due
to the environmental and socio-economic problems asso-
ciated with the use of fossil fuels. In recent time many
novel technologies have been introduced for conversion
of biomass to energy and chemicals. Hydrothermal (HT)
processes are considered as promising technologies for
the conversion of biomass into biofuels and biobased
chemicals.
BIOMASS hyDROThERMAL REFORMING
The production of biobased chemicals and energy
carriers is considered to be carbon-neutral, since the CO2
generated during processing can be absorbed by plants
during their growth. Promising technologies for the con-
version of biomass into biofuels and biobased chemicals
are hydrothermal (HT) processes, which use sub- and su-
percritical water (SubCW, SCW) as processing medium.
Generally, HT processes could be divided into four main
processes: carbonization (HTC), aqueous phase reforming
(APR), liquefaction (HTL), and gasification (HTG). In these
processes water has the role of reactant, solvent, and also
a catalyst. The main advantage over other processing
114 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
methods includes ability to use wet biomass without pri-
or dewatering and enables production of versatile chem-
icals and fuels in gaseous, liquid, or solid state. Extensive
information about the fundamentals and mechanisms of
HT reactions and state of the research is given in the lit-
erature [1]. The global increase in the production of bio-
diesel has led to a simultaneous increase in the amount
of crude glycerol, the main by-product of biodiesel plants.
The identification of high added value outlets for crude
glycerol has become an active research topic.
In the present study supercritical water reforming
(SCWR) of glycerol (10 wt% aqueous solution) was per-
formed at 673, 773 and 873 K and a pressure of 25 MPa for
various residence times. The experiments were carried
out in a high pressure continuous reactor and a compari-
son was made between non-catalyzed and catalyzed re-
actions. Cu/Zn catalyst and Cu/Zn doped with Al and Pb
were used to improve the conversion of glycerol. It was
found that Cu/Zn-Al,Pb catalyst, higher temperatures and
longer residence times favor the gasification of glycerol,
while Cu/Zn catalyst, lower temperatures and shorter res-
idence times promote dehydration over gasification.
The main gases produced during SCWR of glycerol
are H2, CO
2 and CO. The knowledge about the behaviour
of these gases in water under different conditions of tem-
perature and pressure is essential in designing the separa-
tion processes following the conversion reactions. Therefore
we have studied the solubility of H2, CO
2 and CO in water
at high temperature and pressure, and the experimental
data were correlated using various equations of state (Peng
Robinson, van de Waals). The results show that the nature
of the gas influences the behaviour of the water-gas bina-
ry system. Thus the solubility of CO2 in water increases
with increasing pressure and decreasing temperature.
PANEL I: BIO-BASED FUEL PROCESSES 115
Higher pressure also favors the solubility of H2, however
higher amounts of H2 dissolve in water at higher tempera-
ture. The same effect of temperature was observed for CO,
while pressure had an almost negligible effect on its sol-
ubility in water.
ChEMICALS FROM BIOMASS
Fast pyrolysis of biomass give dark brown organic
liquids, commonly termed as bio oils (pyrolysis oil), which
are chemically a complex mixture and/or emulsion of wa-
ter and degradation products of lignin (e.g. guaiacols, cat-
echols, syringols, vanillins), cellulose (such as levoglucosan,
dehydrated sugars, di-sugars, furancarboxaldehydes), and
hemicellulose (such as acetic acid, formic acid), depend-
ing on type of biomass feedstock and conditions of pyrol-
ysis process. Details on the production and the typical
properties of pyrolysis oils are presented elsewhere [2]. As
an alternative fuel, biodiesel, produced from biomass, has
been accepted throughout the world due to its several ad-
vantages. First of all, it is made from renewable sources,
which are usually vegetable oils and animal fats. Biode-
gradability, non-toxicity and low emissions in comparison
to fossil fuels are further advantages which make bio fuels
widely accepted as alternative fuels which are almost sul-
phur and nitrogen free and also carbon dioxide neutral [3].
They are considered as promising alternative fuels for
gasoline and diesel engines. For the systems pyrolysis
oil+diesel+carbon dioxide and pyrolysis oil+tail water+
carbon dioxide as well as for systems hydrogen/pyrolysis
oil and hydrogenated pyrolysis oil fundamental data were
determined [2, 3].
The study of HT reactions of cellulose, a biomass
model substance, in SubCW at temperatures 493, 523, and
573 K and autogenous pressure in batch reactor [4] showed
116 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
that the conversion to main products distributed in liquid,
gaseous and solid phase is strongly dependent on the tem-
perature and residence time. The maximal yield (51.4%)
of water-soluble products was obtained at 523 K and re-
action time of 5 min and the phase was composed mostly
of cellulose decomposition products, such as sugar mono-
mers and monomer degradation products (organic acids,
5-HMF, aldehydes etc.). Maximal yield (21.1%) of bio-oil
was obtained at 523 K and reaction time of 60 min and
consisted mainly of hydrophobic phenols and its deriva-
tives, ketones, carboxylic acids, long-chain alkanes, etc.
Gas yield was maximal (68%) at 573 K and 60 min, what
indicates that non-catalytic gasification of biomass occurs
only at temperatures above 573 K. Char formation was the
most intensive at 523 K and 60 min. The results confirm
that by targeted control of process conditions, selectivity
of reactions to desired products could be influenced.
REFERENCES
[1] I. Pavlovič, Ž. Knez, M. Škerget, Hydrothermal Reactions of Agricul-
tural and Food Processing Wastes in Sub- and Supercritical Water: A
Review of Fundamentals, Mechanisms, and State of Research, J. Ag-
ricultural and Food Chemistry, 6 (2013) 8003-8025.
[2] M. Knez Hrnčič, R. H. Venderbosch, M. Škerget, Ž. Knez, Observation
of phase behavior for bio-oil + diesel + carbon dioxide and bio-oil + tail
water + carbon dioxide system, J. Chemical and Engineering Data, 58
(2013) 648-652.
[3] M. Knez Hrnčič, R. H. Venderbosch, M. Škerget, L. Ilić, Ž. Knez, Phase
equilibrium data of hydrogen in pyrolysis oil and hydrogenated pyrol-
ysis oil at elevated pressures, J. Supercritical Fluids, 80 (2013) 86-89.
[4] I. Pavlovič, Ž. Knez, and M. Škerget, SubcriticalWater — a Perspective
Reaction Media for Biomass Processing to Chemicals: Study on Cel-
lulose Conversion as a Model for Biomass, Chemical and Biochemical
Engineering Quarterly, 7 (2013) 73-82.
SCW TEChNOLOGIES FOR BIOMASS REFINING
117
SCW TEChNOLOGIES FOR BIOMASS REFINING
Maria José coceroSchool of Industrial Engineering,
Sede Mergelina Chemical Engineering Department, Valladolid University;
47011, Valladolid, Spain; E-mail: [email protected]
The development of biobased industries, supported in the
biomass, needs a new philosophy to achieve a decentral-
ized production as an alternative to the well-supported
centralized petrochemical production plants. In order to
accomplish these challenges, research has to enable the
development of environmental compatible process, effi-
ciently handling energy and reducing the equipment costs.
These processes should be characterized by high yield and
high selectivity, simplified number of processes steps by
searching opportunities among new raw materials, and
using clean solvents as water or carbon dioxide. The re-
duction of equipment costs involves the development of
compact apparatus with reduced operation times; reduc-
ing the residence time from minutes to milliseconds allows
a reactor volume reduction from m3 to cm3. The use of
pressurized fluids has been proposed as an environmental
compatible process to integrate the depolymerization-re-
action-separation processes. Particularly, high-tempera-
ture pressurized water has proved to be a good solvent for
clean, safe and environmentally benign organic reactions
[1]. The main reasons that make the hydrothermal media
a promising alternative for biomass processing are: (a) it
is not necessary to reduce the water content in the raw
118 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
material, thus avoiding energy losses; (b) the reaction me-
dium permits the transformation of the different biomass
fractions; (c) the mass transfer limitations are reduced or
avoided, thus allowing faster reaction rates. Furthermore,
the adjustable properties of the reaction medium work as
a control factor for the reaction selectivity, avoiding the
generation of by-products. High pressurized/supercritical
water can be used for several depolymerization biomass
processes as hydrolysis, transformation in high added val-
ue compounds, gasification, fractionation and oxidation
to get energy.
CELLULOSE SCW hyDROLySIS AS PRETREATMENT
TO AChIEVE FERMENTABLE SUGARS
The hydrolysis of cellulose is completed at sub-
critical temperatures, obtaining a high concentration of
glucose and oligosaccharides, but the reaction has a low
selectivity and needs bigger reactors and higher residence
times [2]. Using subcritical water hydrolysis in the pres-
ence of a catalyst, the process can take place at a low
temperature (150 ºC), but the residence time is increased
up to 24 or 48 h [3]. The reactions of cellulose hydrolysis
under supercritical conditions are fast, but, if the reactions
are not controlled, a high quantity of derived products are
yielded [4]. The selectivity of the cellulose hydrolysis in
SCW water can be significantly improved by the reduction
of the residence time. Cantero et al [5] have found out that
the glucose selectivity obtained from cellulose was im-
proved by using ultra-fast reactions in which a selective
medium was combined with an effective residence time
control. A selective production of glucose, fructose and
cellobiose (50%) or total mono-oligo saccharides (>96%)
was obtained from the cellulose in a reaction time of
0.03 s. Total cellulose conversion was achieved with a
PANEL I: BIO-BASED FUEL PROCESSES 119
5-hydroxymethylfural concentration lower than 5 ppm in
a novel micro-reactor. This study shows that the hydroly-
sis of cellulose to glucose and oligomers of glucose can be
performed in residence times between 0.02-0.03 s in SCW
with high selectivity of sugars (up to 98%). The keys to
reducing the production of derived products when SCW
is the reaction medium are: (a) effective control of the res-
idence time, in order to stop the reaction after the total
hydrolysis of cellulose and before the glucose degradation
reactions; and (b) setting the conditions of the media to
favor the hydrolysis reactions and disfavor the degradation
reactions. Furthermore, the SCW glucose hydrolysis is a
high selective reaction media to achieve pyruvaldehyde
and lactic acid [6].
FRACTIONATION OF BIOMASS USING
hIGh PRESSURIzED WATER (hPW)
The fractionation of biomass to obtain high valuable
products as oils and antioxidants, hemicellulose, cellulose,
bio-oils and lining could be achieved by a HPW stepwise
process. The fractionation of grape seeds as a model bio-
mass to understand the combination of extraction and a
hydrothermal fractionation-hydrolysis process is present-
ed. The grape seeds were extracted in a first step with
ethanol/water (75%/25%) at 90 ºC obtaining ca. 13% of oil
and 0.0446 g-GAE/g-grape seeds (66% of the maximum
polyphenols), to obtain the maximum yield and antioxidant
activity. Then grape seeds were treated with high pressur-
ized water using three different temperatures: 250 ºC, 300 ºC
and 350 ºC. The solid residue varied from 0.256-0.358 g/g,
the Light Bio-oil from 0.081-0.157 g/g and High Bio-oil from
0.106-0.162 g/g. The first order kinetics for the hemicellu-
loses and celluloses in our system were k0 = 0.995 g/min
with an activation energy Ea = 13849.6 J/mol. The flow
120 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
rate increases the mass transfer in the system improving
the extraction; however, a maximum was found at a surface
velocity of 2.3 cm/min. During the hydrolysis, the pH de-
creased from 5.5 down to 3.0 due to acetyl groups libera-
tion. Finally, the carbonization of the grape seeds did not
yield to clear nanosize structures as other materials do.
REFERENCES
[1] K. Arai, R. L. Smith, T. M. Aida, J. Supercritical Fluids, 47(3) (2009)
628-636.
[2] T. Rogalinski, T. Ingram, G. Brunner, J. Supercritical Fluids, 47(1) (2008)
54-63.
[3] Z. Fang, F. Zhang, H.-Y. Zeng, F. Guo, Bioresource Technology, 102(17)
(2011) 8017-8021.
[4] M. Sasaki, K. Goto, K. Tajima, T. Adschiri, K. Arai, Green Chemistry, 4(3)
(2002) 285-287.
[5] D. Cantero, M. D. Bermejo, M. J. Cocero, Bioresource technology,
135 (2013) 697-703.
[6] D. Cantero, M. D. Bermejo, M. J. Cocero, J. Supercritical Fluids, 75
(2013) 48-57.
SUSTAINABLE TEChNOLOGIES FOR OIL-BASED SECOND GENERATION BIOREFINERIES
121
SUSTAINABLE TEChNOLOGIES FOR OIL-BASED SECOND GENERATION BIOREFINERIES
n. cotabarren, p. hegel, s. peredaPlanta Piloto de Ingeniería Química,
Universidad Nacional del Sur (PLAPIQUI-UNS-CONICET); Camino La Carrindanga Km 7 – CC 717,
8000, Bahía Blanca, Buenos Aires, Argentina;E-mail: [email protected]
A biorefinery is, by definition, the integrated production
of food, fodder, chemicals, materials, goods, and fuels by
means of bio- or physicochemical processing of biomass.
In that sense, human bodies are a good example of bio-
mass processing to recover energy and chemicals to pro-
duce materials; however, the atomic efficiency of modern
societies is quite low. Even worse, as can be seen in big
cities, the richer the population is, more residues it produc-
es. Losses in the feed chain have not yet been seriously
examined. In summary, the second-generation biorefiner-
ies not only should process non edible biomass, but also
it should push forward the gain of edible biomass resourc-
es. In that sense, new technologies for biomass recycling
and residues processing are needed to enhance the bio -
economy matrix. It is important to look at food processing
industrial centers and urban residues. For example, the
great increase of worldwide production of soybean and
sunflower oil, impacted not only in the oil market but also
in the oil refining by-products (phospholipids sludge and
distillates of the deodorizer), which prices are rapidly chang-
ing. Even though these residues contain high-added value
products, their cost are decreasing, becoming sometimes
a waste with disposal-associated problems. Furthermore,
122 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
sludge processing to recover oil or phospholipids is com-
plex. Because of its high viscosity and poor flow properties
(sticky behavior), its processing needs large volumes of
solvent, and consequently, it is expensive. An alternative
sustainable technology is the direct alcoholysis of phos-
pholipids and vegetable oil (triglycerides) occluded in the
wet gum using supercritical ethanol to produce fatty acids
ethyl esters (FAEE). Oil gums contain approximately 45%
water, 25% oil and 30% phospholipids. Therefore, the con-
ventional alkaline process is a non-viable alternative to
produce fatty esters from SOGs. By contrast, the trans-
esterification process by supercritical alcoholysis is an
interesting option for this unconventional and low-cost
feedstock [1]. On the other hand, with respect to high add-
ed value chemicals, in biodiesel processing plants acyl-
glycerols can be economically produced. Acylglycerols are
common food emulsifiers and surface active agents in many
industrial cleaning products. Commercial MG is obtained
via an alcoholysis pathway in which either fatty acids or
a fat are reacted with an excess of glycerol. The reaction
products contain mainly mono-, di-, tri-glycerides (MG,
DG, TG, respectively) and glycerol, but depending on the
glycerol/fat ratio the MG composition fluctuates between
40 and 60% of MG [2]. A further refined MG up to around
90 wt% purity, also called “high mono”, is conventionally
obtained by short path distillation of the reaction products
at ca. 473 K and 0.01 mbar or less [2]. This process is ex-
pensive and recovers only part of the produced MGs. More-
over, MG concentration higher than 96 wt% cannot be
achieved by vacuum distillation because of interesterifi-
cation reactions causes degradation of MG towards glycer-
ol and free fatty acids. Peter et al. [3] proposed an interesting
alternative to obtain 99 wt% purity of MG from the acyl-
glycerides mixture by means of supercritical fluid extrac-
PANEL I: BIO-BASED FUEL PROCESSES 123
tion using mixtures of carbon dioxide and propane as
extraction solvents. An alternative pathway to produce
MG, instead of transesterification, is the glycerolysis of
fatty acid methyl esters. In this case the separation prob-
lem downstream of the reactor completely changes. Puri-
fication of MG from a mixture of biodiesel can be carried
out with pure CO2 as a green solvent [4]. CO
2 presents
complete solubility with fatty esters in a wide range of
temperature and pressure, and exhibits partial miscibility
with acylglycerols (both in liquid and supercritical state).
This alternative appears as a promising process with direct
application in the biodiesel and food industry. Nowadays
strong regulations are set on oil-based biorefineries to use
nonedible vegetable oils. In that respect, the urban resid-
ual oils and fats are an interesting source of fatty acids for
biodiesel production. The commercial process to convert
used cooking oil (UCO) to used cooking oil methyl esters
(UCOME) is a pretreatment of the oil with high content of
fatty acids. The acid oil can be reacted with glycerol to
produce a mixture of acylglycerols, which are fed in a
transesterification plant, after its purification by vacuum
distillation [5]. Due to the immiscibility of the reactants,
the reaction rate is very low. In order to enhance the mis-
cibility it is carried out at temperatures above 200 ºC, but
the long residence time causes thermal degradation of the
raw materials, which end up in highly contaminating ef-
fluents. A phase equilibrium engineering of this reaction
requires thermodynamics models able to predict the mul-
tiphase behavior. GCA-EoS is a group contribution with
association model that has shown good traits to predict
phase behavior of these types of mixtures. In this presen-
tation, sustainable technologies for residues processing
and vegetable oil recycling will be discussed. Moreover,
also a high pressure technology for high purity mono-
124 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
glycerides recovery will be presented. Integration of the
discussed technologies may contribute to pave the way
towards oil-based second generation biorefinery develop-
ment. Finally, trends in the field of oil recycling and oil
based fuels other than biodiesel will be discussed.
REFERENCES
[1] G. Soto, A. Velez, P. Hegel, G. Mabe, S. Pereda, J. Supercritical Fluids,
79 (2013) 62.
[2] W. Fischer, DGF-Symposium in Germany (1998).
[3] S. Peter, B. Czech, U. Ender, E. Weidner, US Patent 5 434 280 (1995).
[4] G. SOTO, P. HEGEL, S. PEREDA, III Iberoamercian Conference on Su-
percritical Fluids, Cartagena de India, Brazil, 2013.
[5] P. Felizardo, J. Machado, D. Vergueiro, M. J. N. Correia, J. Pereira Gomes,
J. Moura Bordado, Fuel Processing Technology, 92 (2011) 1225.
BIODIESEL PURIFICATION USING SUPERCRITICAL CO2
125
BIODIESEL PURIFICATION USING SUPERCRITICAL CO2
Marcos L. corazza, papa M. ndiaye, Alexis M. EscorsinFederal University of Paraná;
Francisco H dos Santos, 100, Curitiba, PR, Brazil; E-mail: [email protected]
Currently there is great interest in developing new meth-
ods and processes focusing on biodiesel production and
purification. Regarding conventional transesterification
process for biodiesel production the use of water for bio-
diesel washing aiming the removal of glycerol, diacyl-
glycerol, monoacylglycerol, salt and other contaminants
is expensive and request a high water to biodiesel ratio
consumption. It is estimated that 3 L of water are used for
1 L of pure biodiesel produced. Thus, the development of
new processes that minimize the water consumption for
biodiesel production can be interesting from environmen-
tal and economic point of view. Due to the low solubility
of glycerol, acylglycerols (MAG, DAG and TAG) and salts
in supercritical CO2, it will be presented in this lecture
that soybean biodiesel can be efficiently separated and
purified from the reacting mixture (named crude biodies-
el) by using supercritical CO2 injection. Initially, we have
measured the phase equilibrium for the systems (m)etha-
nol(1) + glycerol(2) + CO2(3), at three different alcohol to
glycerol molar ratios (12:1, 20:1 and 30:1) and (m)ethanol(1)
+ biodiesel(2) + CO2(3), at alcohol to biodiesel molar ratio
of (3:1 and 8:1), at temperature ranged (303 K-353 K). The
high immiscibility for the systems containing the glycerol
was experimentally observed. For the systems (m)ethanol(1)
126 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
+ glycerol(2) + CO2(3) the occurrence of vapor-liquid,
liquid- liquid and vapor-liquid-liquid equilibrium were ob-
served. Regarding the biodiesel purification a given amount
of CO2 was injected using a variable-volume view cell con-
taining the mixture of crude biodiesel. The cell was then
pressurized in the range of 6-12 MPa at temperature vary-
ing from ambient (298 K) to 323 K. The amount of carbon
dioxide injected in the crude biodiesel varied from 20 wt%
to 50 wt%. Two phases were formed at the end of the pro-
cess. By mean of one-way valve, the lighter phase was
sampled and diacyglycerol, monoacylglicerol, glycerol,
biodiesel, sodium and methanol content were analyzed
using Gel Permeation Chromatography (GPC) and gas chro-
matography (GC). Results were then compared to the con-
ventional biodiesel production from a transesterification
process. The characterization was done in accordance with
the standards specification of the National Agency of Pe-
troleum, Natural Gas and Biofuels (ANP/Brazil). An exper-
imental design was performed to investigate the influence
of carbon dioxide composition, pressure and temperature.
Results obtained have showed that this process can be
able to produce a biodiesel with low levels of diacylglyc-
erol, monoacylglycerol, biodiesel (fatty acid methyl esters),
sodium, glycerol and methanol. From the results obtained
it can be seen that the temperature was the variable that
most affects the purification of biodiesel while the carbon
dioxide concentration and the pressure has a minor effect.
The best condition was obtained at low temperature. In a
general way, in this proposed process the obtained bio-
diesel presented lower levels of sodium, glycerol and meth-
anol contents than the values specified by the National
Agency of Petroleum, Natural Gas and Biofuels (ANP/
Brazil). This process represents a promising technique in
further biodiesel downstream purification steps.
CRITICAL FLUIDS APPLICATION FOR EFFICIENT PROCESSING OF LIGNOCELLULOSE BIOMASS AS PART OF AN INTEGRATED BIOREFINERy
127
CRITICAL FLUIDS APPLICATION FOR EFFICIENT PROCESSING OF LIGNOCELLULOSE BIOMASS AS PART OF AN INTEGRATED BIOREFINERy
Regina c. D. santosUniversity of Birmingham;
Edgbaston, B15 2TT, Birmingham, West Midlands, UK; E-mail: [email protected]
It is widely acknowledged that lignocellulose biomass
derived from forestry, energy crops, agricultural and food
processing residues represents a significant renewable
resource that has yet to be exploited to its full potential.
Fermentation, either liquid or solid state are accepted routes
by which it is thought lignocellulose biomass can be up-
graded to liquid and gaseous bioenergy carriers and even-
tually platform chemicals, reducing our current dependence
on fossil fuels. However, the recalcitrant nature of ligno-
cellulose reduces fermentation efficiency. Attempts to
overcome the resistant structure of the biomass have led
to extensive research in the area of ‘pre-treatment’. To
date there are a large number of reports describing the
application of acid, alkali, and other solvents, combined
with a range of physical treatments. However most if not
all, while breaking down the physical barrier, often induce
the production of either naturally occurring or novel chem-
ical intermediates that conspire to again reduce fermen-
tation efficiency. The work currently being undertaken
at the University of Birmingham, School of Chemical En-
gineering will be presented, where researchers are eval-
uating and developing strategies to optimise biomass
pre-treatment and therefore maximise the potential of
lignocellulose utilisation in downstream fermentation.
PANEL PRESENTATIONS
Panel II: New Materials and Materials Processing
SyNThESIS OF METALLIC NANOPARTICLES USING SUPERCRITICAL FLUIDS
131
SyNThESIS OF METALLIC NANOPARTICLES USING SUPERCRITICAL FLUIDS
M. crone, s. Müller, M. TürkDepartment of Chemical and Process Engineering,
Karlsruhe Institute of Technology (KIT); Engler-Bunte-Ring 21, 76131, Karlsruhe, Baden-Württemberg, Germany;
E-mail: [email protected]
In the 21st century, manufacturing as well as service in-
dustries must increasingly attempt to avoid production,
use, and release of harmful substances into our environ-
ment. Furthermore, discovering environment-friendly and
renewable energy sources is one of the major challenges
in the present and future. As a result of these two factors
new processes must be therefore environmentally friend-
ly when employed at a large scale. During the last thirty
years numerous technological advances indicate that the
use of supercritical fluids (SCFs) enables the overcoming
of these environmental problems and offers new and prom-
ising pathways for material processing. SCFs are charac-
terized by densities very close to those of liquids and mass
transfer properties lying between those of gases and liq-
uids. Depending upon the fluid density, the fluid may be
tuned to behave as a specific solvent for a specific sub-
stance at one pressure, but as a non-solvent at another
pressure. SCF-based processes are characterized as envi-
ronment-friendly due to the low-energy solvent and prod-
uct recovery. In addition a solvent-free product can be
obtained in a single processing step by partial system
depressurization. These specific characteristics of SCFs
can be exploited to design and synthesize new materials
132 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
— in particular nanoparticles — for advanced performance
in numerous applications. Nanoparticles, i.e. particles
which have at least one dimension on the nanometer scale
(1 to 100 nm) have become more and more important in a
large number of technological important areas such as
chemistry, energy, electronics, optics and pharmacology.
Noble metal nanoparticles and, in particular, platinum (Pt)
nanoparticles have demonstrated to be efficient catalysts
for chemical reactions such as hydrogenation, hydration
and oxidation [1]. They are often prepared by aqueous
impregnation of a porous support with a metal-containing
solution, followed by reductive treatment. Catalysts pre-
pared by this procedure yield to metal particles with broad
size distribution and to large volumes of waste water. A
promising environment-friendly alternative to this con-
ventional preparation route is the application of SCFs to
achieve high dispersions of noble nanoparticles on po-
rous supports (e.g. TiO2, Al
2O
3, Black Pearls, Carbon nano-
tubes) [2]. Material design using methods involving SCFs
is achieved through two distinct processes. Particle forma-
tion can thus be based on either a physical transformation
(e.g. rapid decompression, anti-solvent effect.) or a chem-
ical reaction. In case of the second method, metallic nano-
particles can directly be deposited on various solid supports
by Supercritical Fluid Reactive Deposition (SFRD) [3]. In
this process, the SCF acts as a solvent, reaction and sep-
aration media. The SFRD technique involves the dissolu-
tion of the organometallic precursor in a SCF (e.g. scCO2)
and the exposure of a support to the solution. After suffi-
cient time for impregnation, the precursor will be trans-
formed to its metal form with a reducing agent, such as
hydrogen. Different methods can be used to convert the
organometallic precursor to its metal form: a) chemical
reduction in scCO2 with hydrogen, b) chemical reduction
PANEL II: NEW MATERIALS AND MATERIALS PROCESSING 133
at atmospheric pressure with hydrogen, c) thermal reduc-
tion in scCO2, and d) thermal reduction at atmospheric
pressure in an inert atmosphere. Usually method b) was
only used on selected samples for comparison while meth-
od a) was the preferred process. At the end of these ex-
periments, the system is slowly depressurized and cooled
down to ambient conditions. Since both, CO2 and the re-
action products are in the gaseous state, phase separation
can be easily realized and a solvent free product is ob-
tained. Thus, the SFRD technique represents an integrat-
ed process that enables process intensification because
it combines several steps of the conventional process. In
our investigation, the influence of different organometal-
lic precursors, various supports and reduction conditions
on particle size, size distribution, and metal loading was
investigated. The product was characterized by scanning
and (high resolution) transmission electron microscopy
(SEM and HRTEM), energy-dispersive X-ray spectroscopy
(EDXS), powder X-ray diffraction (XRD), and ICP-OES anal-
yses. First, this talk will give an introduction into the ba-
sics of the SFRD process, including a short discussion of
the solubility and the phase behaviour of the precursor in
the SCF as well as of the adsorption behaviour of the pre-
cursor on the support. Based on this, typical results ob-
tained from SFRD experiments are presented and discussed.
In summary, the results of our investigations show that:
1) The average particle size and size distribution can
be affected by type and amount of the precursor in
the system, precursor reduction method and con-
dition, surface properties (surface area and chem-
ical nature) of the support [3].
2) The SFRD process enables the formation of uniform
Pt, Pd, Au, Ag- and bimetallic (Au-Ag) nanoparticles.
134 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
3) Adsorption behaviour determines the metal amount
which can be deposited on the support.
4) Pt- and Pt/Cu-catalysts prepared by SFRD exhibit-
ed an activity higher than reference samples pre-
pared by conventional wet impregnation [4,5].
At the end of the talk the main conclusions and
further perspectives are summarized and discussed.
REFERENCES
[1] C. J. Zhong, M. M. Maye, J. Luo, L. Han, N. Kariuki, Nanoparticles in
catalysis, in: V. Rotello (Ed.) Nanoparticles: building blocks for nano-
technology. Kluwer Academics, Plenum Publishers; NY, 2004, 113.
[2] C. Erkey, J. Supercritical Fluids, 47 (2009) 517.
[3] V. Aggarwal, L. Reichenbach, M. Enders, Th. Muller, S. Wolff, M. Crone,
M. Türk, S. Bräse, Chemistry European J., 19 (2013) 12794.
[4] G. Incera Garrido, F. C. Patcas, G. Upper, M. Türk, S. Yilmaz, B. Kraushaar-
Czarnetzki, Applied Catalysis A: General, 338 (2008) 58.
[5] S. Lang, M. Türk, B. Kraushaar-Czarnetzki, J. Catalysis, 286 (2012) 78.
SUPERCRITICAL CARBON DIOxIDE DRyING OF SILICA ALCOGEL: STATE-OF-ThE-ART AND OUTSTANDING NEEDS
135
SUPERCRITICAL CARBON DIOxIDE DRyING OF SILICA ALCOGEL: STATE-OF-ThE-ART AND OUTSTANDING NEEDS
Marc hodesMechanical Engineering Department,
Tufts University; 200 College Ave., Medford, MA, 02155, USA;
E-mail: [email protected]
Aerogels are dry, nanoporous, nanostructured materials
with unique and extreme properties including ultra-low
density and thermal conductivity. To date the commercial
focus of aerogels has been superinsulation. Indeed, heat-
ing and cooling of buildings in the United States, e.g.,
accounts for 15% of energy consumption and 32% of CO2
emissions and the superinsulating properties of commer-
cially-available aerogel blankets can immediately and
substantially reduce these numbers. Unfortunately, aero-
gel superinsulation is 10 times more expensive than con-
ventional insulation; say, polyurethane. Hence, while the
worldwide insulation market is about $40 billion, aerogels
account for less than 1% of it and it is projected that the
aerogel industry will grow to only $330 million by 2017.
The two common techniques for removing the alcohol from
the pores of a silica alcogel and replacing it with air there-
by affording an aerogel are ambient pressure drying and
supercritical carbon dioxide (scCO2) drying, the focus here.
scCO2 drying enables extraction of solvent from a gel while
preserving the delicate nanostructure of its solid skeleton
by eliminating phase boundaries and thus capillary forc-
es. Beneficially and unlike direct supercritical extraction,
scCO2 drying is a low temperature and nonflammable pro-
136 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
cess. However, scCO2 drying requires substantial infra-
structure, i.e., expensive pressure vessels, fluid handling
equipment, and process control hardware, and copious
amounts of CO2. Moreover, scCO
2 drying and CO
2 recycling
are cost- and energy-intensive and, importantly, drying is
the rate-limiting step in the manufacture of aerogels.
We discuss the state-of-the-art in scCO2 drying of
alcogels with a focus on the drying kinetics study recent-
ly completed at Tufts University. In this study we dried 5,
10 and 15 mm-thick x 56 mm OD x 220 mm-tall annuli of
alcogel that were concentric with a 56 mm ID x 76 mm
OD annular gap through which scCO2 flowed. This was
accomplished over a range of CO2 mass flow rates (1 kg/
hour to 5 kg/hour), operating pressures (100 bar to 138 bar),
and operating temperatures (50 oC to 70 oC) using two
different solvents, i.e., ethanol and methanol. Alcohol ex-
traction rates were continuously measured for the first time.
The total mass flow rate of scCO2 plus alcohol leaving the
reactor was measured using a Coriolis flow meter. Down-
stream of this flow meter, the effluent flowed through a
series of heated decompression valves and separated into
liquid and vapor streams. The mass flow rate of liquid
alcohol was measured using a collection beaker and bal-
ance. The mass flow rate of alcohol in the vapor stream
was computed from measurements of the mass fraction
of alcohol in it using an infrared hydrocarbon sensor and
extraction rate versus time then computed. Comparison
between theory and data showed mass transfer to be a
diffusion-limited process, except at sufficiently low scCO2
mass flow rates, where the mass transfer driving force was
depleted due to the buildup of ethanol in the scCO2 stream
flowing over the alcogel. It was necessary to utilize a con-
centration-dependent molecular diffusivity to properly pre-
dict drying kinetics.
PANEL II: NEW MATERIALS AND MATERIALS PROCESSING 137
Our presentation concludes with a discussion of
outstanding needs which must be addressed to accelerate
and reduce the cost of scCO2 drying. These include the
development of experimentally-validated equations of state
to compute the density of ethanol-CO2 and methanol-CO
2
mixtures at process conditions. Once such data are avail-
able, installing a Coriolis flow meter in the effluent stream
enables pressure, temperature and density to be simulta-
neously measured and, importantly, mass fraction of al-
cohol in the effluent to be computed. Then, the mass flow
rate of alcohol leaving the extractor vessel equals solute
mass fraction times effluent mass flow rate, and integrat-
ing this quantity over time enables the fraction of the total
alcohol initially in the extractor to be monitored. A second
outstanding need is measurement of concentration-de-
pendent molecular diffusion coefficients in relevant systems
at process conditions. It is suggested that the laser-induced
grating method be used for this purpose because it is
non-intrusive, has been successfully utilized to measure
(Soret, thermal and mass) diffusion coefficients in super-
critical water and, finally, unlike more common techniques
such as those based on Taylor dispersion, it applies across
the full range of solute concentrations. Finally, elucidation
of the effects of “suction” and “swelling” in alcogels during
drying due to the non-monotonic dependence of density
on solute concentration need be resolved.
BEyOND ThE BARRIER IN GAS FOAMING: hOLLOW POLyMERIC MICRO- AND NANOPARTICLES
139
BEyOND ThE BARRIER IN GAS FOAMING: hOLLOW POLyMERIC MICRO- AND NANOPARTICLES
s. orsi, E. Di Maio, p. A. netti, s. iannaceDepartment of Chemical, Materials and production Engineering,
University of Naples; P.le Tecchio 80, 80125, Naples, Italy;
E-mail: [email protected]
hollow polymeric nanostructures have huge scientific and
industrial value. In particular, they are used for encapsu-
lation of drugs, enzymes, proteins and genes in biomedi-
cal and pharmaceutical applications, for contrast agents
for diagnostic as nanoreactors in chemistry and chemical
engineering, as transducers and dielectrics in electronics.
The current methods for the preparation of hollow poly-
meric nanostructures include: emulsion polymerization,
suspension poly-merization, core-shell precursors, self-as-
sembly, electrospraying and template-directed synthesis.
The aim of this work is to introduce gas foaming as a suit-
able technology to produce hollows in micro- and nano-met-
ric polymeric particles. Gas foaming is a common technique
to generate hollows in bulk polymeric materials. Gas es-
cape from super-saturated polymer/blowing agent solution
is the driving force to bubble nucleation and growth. How-
ever, gas escape also determines a gas loss through the
external free surface, in particular in the 10-100 microns-
thick layer of the polymeric matrix in contact with the ex-
ternal surface. This phenomenon essentially impedes the
use of the gas foaming technology to produce hollow mi-
cro- and nano-metric particle, since the whole volume,
essentially, is so close to the external surface that the dif-
140 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
fusive path available to the gas within the induction time
required for foaming. The proposed approach consists of
retarding the gas loss from the free surface by embedding
the particles in a removable barrier film. In doing so, we
introduce an obstacle to mass transport that hinders gas
loss from the free surface, at least within the time required
for bubble nucleation, thereby allowing the phase sepa-
ration within the particle. Barrier film-embedded polysty-
rene spheres were prepared by dispersing polystyrene
spherical particles (500-50-5-0.5-0.2 µm in diameter) (Duke
Scientific) dispersed in aqueous solutions poly(vinyl alco-
hol) (PVA) (Mowiol 40-88, Sigma-Aldrich, dried at room
temperature for 72 h). Bare polystyrene spheres (without
the barrier film) were also analysed and subjected to the
following foaming process. For the production of foamed
samples, a thermo regulated and pressurized cylinder hav-
ing a volume of 0.3 L, (model BC-1, HiP Erie, US-PA) was
used. The pressure discharge system consists of a dis-
charge valve (model 15-71 NFB, HiP Erie, US-PA), an elec-
tromechanical actuator (model 15-72 NFB TSR8, HiP Erie,
US-PA) and an electro-valve. The pressure history was reg-
istered by using a data acquisition system (DAQ PCI6036E,
National Instruments, US-TX) and a pressure transducer
(model P943, Schaevitz-Measurement Specialties, Hamp-
ton, US-VA). In a typical experiment, the samples (barrier
film-embedded polystyrene spheres and bare polystyrene
spheres) were loaded into the vessel, pressurized with the
blowing agent at 14 MPa and 100 °C for two hours and
pressure quenched at 100 MPa/s. Particles were recovered
by dissolving the PVA films in water at room temperature
and washed centrifuging with water five times. To verify
particle morphology, Focused Ion Beam-Scanning Electron
Microscopy, Transmission Electron Microscopy and Con-
focal Microscopy were used. Results show hollow particles
PANEL II: NEW MATERIALS AND MATERIALS PROCESSING 141
achieved with the use of a barrier film embedding the par-
ticles with diameters ranging from 50 microns to 200 nano-
meters. The three order of magnitude spam in the particles
dimension is an evidence of the high versatility of the pro-
posed methodology. It is worth of note, furthermore, that
PS bare particles (not embedded in PVA and collected on
a permeable substrate) did not present any hollow, at all
scales and experimental conditions. Finally, the proposed
methodology has a high efficiency in terms of number of
affected particles versus total number of particles. Among
the many peculiar characteristics of the proposed meth-
odology, it is simple, economic, environmentally friendly,
robust, controllable and does not need any fine chemistry
in polymer synthesis, emulsion or suspension preparation.
Furthermore, it is suitable for a wide range of particle di-
mensions and shapes and allows achieving a large variety
of possible pore structures. As a counterpart, however, the
proposed methodology allows for a reduced control of the
pore morphology and a subsequent sorting of particles
could be necessary for specific applications.
PERSPECTIVES ON ThE USE OF COMPRESSIBLE FLUIDS IN ThE PREPARATION AND PROCESSING OF POLyMER SySTEMS FOR DRUG DELIVERy APPLICATIONS
143
PERSPECTIVES ON ThE USE OF COMPRESSIBLE FLUIDS IN ThE PREPARATION AND PROCESSING OF POLyMER SySTEMS FOR DRUG DELIVERy APPLICATIONS
sandro R. p. da RochaWayne State University;
5050 Anthony Wayne Dr, 48085, Detroit, MI, USA; E-mail: [email protected]
Polymers find a wide range of potential applications in
the biomedical industry, including as drug depots and
carriers that may afford (a) protection to sensitive cargo,
and strategies for the (b) controlled release and (c) target-
ing of therapeutic molecules to desired tissues, so as to
enhance their efficacy and safety profiles. Supercritical or
(more generally speaking) compressible fluid (SCF)-based
technologies offer unique opportunities in terms of both
polymer preparation and their processing with therapeu-
tics for drug delivery applications.
Supercritical CO2 (scCO
2) is of especial relevance
as a polymer reaction and processing medium for drug
delivery applications as it is non-toxic, non-flammable,
relatively inert, and it can be sourced with high purity.
scCO2 also has excellent mass and heat-transfer proper-
ties, and low surface energy. Moreover, the separation of
scCO2 from the polymer product or drug-polymer system
is facilitated as scCO2 can be reverted to the gaseous state
by simple depressurization, thus eliminating energy inten-
sive solvent removal steps that exist in processes involving
conventional solvents. However, there are many challenges
in using scCO2 for polymer preparation and processing with
therapeutics, perhaps one of the most notable being the
fact that while most monomers are soluble in scCO2, most
144 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
polymers (and many small molecular weight therapeutics
for that matter) are not.
The good news is that the very same characteristics
that challenge the use of scCO2 in polymer synthesis and
polymer-drug processing, such as its poor solvent power,
can actually be turned around and used as unique oppor-
tunities to develop groundbreaking technologies, both in
terms of reaction medium and in the development of de-
pots for drug delivery applications.
For example, the fact that most polymers are insol-
uble in scCO2 is what makes scCO
2 an excellent candidate
medium for the development of innovative dispersion-
based polymerization strategies. While most polymers are
not soluble in scCO2, they can be plasticized by scCO
2.
This characteristic, along with its low viscosity and high
diffusivity, points to scCO2 not only as a good solvent can-
didate, but as a unique solvent environment in dispersion
polymerization. For example, scCO2 has been reported as
a reaction medium that facilitates the access of growing
chain ends and RAFT polymerization agents to monomers
arriving into the growing latex, thus leading to a more
efficient polymerization strategy [1].
Another interesting example of turning things/per-
ceived disadvantages of scCO2 around comes from the fact
that scCO2 is poorly miscible with water, and miscibility
gaps can be found with organic solvents. These charac-
teristics may provide opportunities for the development of
novel emulsion-type polymerization and co-polymerization
strategies, strategies which have been scantly explored.
New opportunities in this area may also arise due to recent
advancements in surfactant design for those interfaces,
and better understanding of microemulsion formation in
scCO2-based systems.
Yet another example of potential contributions of
scCO2-based technologies is in the preparation of polymer
PANEL II: NEW MATERIALS AND MATERIALS PROCESSING 145
drug depots. While most polymers have low solubility in
scCO2, scCO
2 itself can be used to plasticize polymer ma-
trices for enhanced blending of other polymers [2] or im-
pregnation with therapeutic molecules [3]. scCO2 can also
be used to prepare polymer micro- and nanoparticles, and
polymer fibers [4] with encapsulated drug solutes. scCO2
in this case may offer great advantages compared to tra-
ditional methods where the drug molecules may be water,
organic solvent or heat labile, as for example protein ther-
apeutics.
In spite of the potential advantages of scCO2 in the
synthesis of polymeric materials and their processing for
drug delivery applications, commercial processes involv-
ing such systems are very limited. The ability to promote
the future utilization of scCO2-based technologies in this
area hinges on our ability to continue to develop process-
es where scCO2 is not only a good alternative solvent, but
the superior choice or the unique route for product devel-
opment, along with stricter environmental laws, so as to
tip the balance towards cleaner technologies.
REFERENCES
[1] J. Jennings, M. Beija, A.P. Richez, S.D. Cooper, P. E. Mignot, K. J.
Thurecht et al., One-Pot Synthesis of Block Copolymers in Supercritical
Carbon Dioxide: A Simple Versatile Route to Nanostructured Micro-
particles, J. American Chemical Society, 134 (2012) 4772-81.
[2] C. A. Kelly, A. Naylor, L. Illum, K. M. Shakesheff, S. M. Howdle, Su-
percritical CO2: A Clean and Low Temperature Approach to Blending
PDLLA and PEG, Advanced Functional Materials, 22 (2012) 1684-91.
[3] C. Gonzalez-Chomon, M. E. M. Braga, H. C. de Sousa, A. Concheiro,
C. Alvarez-Lorenzo, Antifouling foldable acrylic IOLs loaded with nor-
floxacin by aqueous soaking and by supercritical carbon dioxide tech-
nology, European J. Pharmaceutics and Biopharmaceutics, 82 (2012)
383-91.
[4] L. Li, Z. Jiang, Q. Pan, T. Fang, Producing Polymer Fibers by Electro-
spinning in Supercritical Fluids, J. Chem-Ny. (2013).
NANOSTRUCTURATION OF POLyMER MATRICES By ExTRUSION ASSISTED WITh A SUPERCRITICAL FLUID
147
NANOSTRUCTURATION OF POLyMER MATRICES By ExTRUSION ASSISTED WITh A SUPERCRITICAL FLUID
Jacques fages, Elisabeth Rodier, Martial sauceau, nibal hijazi, nicolas Le Moigne, Jean-charles Benezet,
Tamás vigh, Zsombor nagy, gyorgy MarosiÉcole des Mines – CNRS – RAPSODEE research centre;
Campus Jarlard, 81013, Albi, France; E-mail: [email protected]
In an eco-design and sustainable development perspec-
tive, many research works have recently been devoted to
bio-sourced polymers. Manufacturing nano-composite with
a polymeric matrix incorporating either an active pharma-
ceutical ingredient or a bio-filler may enlarge the field of
applications of such structures towards several industrial
areas: pharmaceuticals, detergents, fine chemicals, etc.
In this lecture a few examples of nano-composite manu-
facturing process will be presented based on a supercritical
carbon dioxide-aided extrusion process (acronym: XSCF).
Pharmaceutical extrusion also known as HME (hot melt
extrusion) is an efficient technology used to disperse drugs
in a melt up to a true molecular solution of a pharmaceuti-
cal ingredient. Most of the applications describe the prepa-
ration of solid dispersions by HME either to increase the
aqueous solubility and oral bioavailability of the active
substance or to control its release. The mostly reported
advantages of HME are: (a) avoidance of organic solvent;
(b) reduction of processing steps (one-pot method); (c)
elimination of the good compressibility requirement for
the active ingredients and the excipients; (d) high level of
drug content; (e) even dispersion of the drug throughout
the matrix; and (f) improved bioavailability through drug
148 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
solubilisation or molecular level dispersion in water solu-
ble matrix. The injection of scCO2 in the extrusion process
modifies the rheological properties of the polymer, and also,
scCO2 acts as a blowing agent at the die exit. In the bar-
rel of the extruder, the reduction of viscosity decreases the
mechanical constraints and the operating temperature.
At the die exit, the pressure drop induces a thermodynam-
ic instability in the polymer matrix, generating a large
number of bubbles, which can grow until the foam is ri-
gidified when temperature drops below the glass transi-
tion temperature, Tg. The influence of several operating
parameters, die geometry and temperature, polymer crys-
tallinity, upstream pressure, addition of nanoparticles will
be discussed. It could be concluded that the combination
of extrusion with scCO2 allows processing relatively frag-
ile or thermally sensitive molecules, like pharmaceutical
molecules, without any residue in the final material. A few
examples of XSCF implementation leading to significant
improvements in drug dissolution kinetics will be pre-
sented. Extrusion is a widely used process to prepare
nanocomposites with silicate-layered materials. Both melt
intercalation and exfoliation can be obtained by XSCF. An
example with PHB-HV and Cloisite, a natural montmoril-
lonite clay, will be given. A new approach can be to gen-
erate nanoparticles from a biobased polymer to be used
as a filler in a matrix. In our laboratory, we have been
working with chitosan, a polysaccharide derived from shell-
fish and some fungi. It has several properties including
biodegradability, antibacterial and antifungal activities,
making it a material of choice for applications in packag-
ing and medical field. Particles were generated by a clas-
sic SAS process (Supercritical Anti-Solvent), minimizing
the use of organic solvents. scCO2 acts as an anti-solvent
while chitosan is dissolved firstly in an acidic aqueous
PANEL II: NEW MATERIALS AND MATERIALS PROCESSING 149
solution to which ethanol has been added to improve the
anti-solvent effect of the sc-CO2. Two coaxial capillaries
allow the injection of the chitosan solution (the inner one)
and CO2-sc (the outer one) in an autoclave filled with CO
2
in which the particles are generated at 18 MPa and 306
K. The miscibility of the CO2 with ethanol and acetic acid,
the solvent of chitosan, induces the reduction of the sol-
vating power of the latter, which causes the crystallization
of the particles. The sc-CO2 loaded with solvents is sent
to three separators where gradual depressurization will
separate the solvents and purify the CO2, that returns af-
terwards to the autoclave. Using this process, we gener-
ated chitosan nanoparticles with an average size of 378
± 13 nm and a positive mean zeta potential of 26.4 ± 0.2
mV. We have also developed a more innovative process,
which led to nanoparticles of chitosan without any organ-
ic solvent. A further step, under present investigation, is
to disperse these nanoparticles by extrusion in a biopoly-
mer matrix, to produce a composite material for biomed-
ical application.
REFERENCE
f M. Sauceau, J. Fages, A. Common, C. Nikitine, E. Rodier, New chal-
lenges in polymer foaming: a review of extrusion processes assisted
by supercritical carbon dioxide, Progress in Polymer Science, 36 (2011)
749-766.
OPPORTUNITIES IN FABRICATION OF hIGh POROSITy NANOFIBROUS STRUCTURES
151
OPPORTUNITIES IN FABRICATION OF hIGh POROSITy NANOFIBROUS STRUCTURES
carson MeredithSchool of Chemical & Biomolecular Engineering,
Georgia Institute of Technology; 311 Ferst Dr., 30332-0100, Atlanta, GA, USA;
E-mail: [email protected]
Nanofibrous structures with high surface area are appeal-
ing to a wide range of practical applications in energy-re-
lated fields. These include white reflective surfaces for
energy-efficient roofing, insulation, catalyst supports, sen-
sors, filtration media and absorbents, lightweight structur-
al materials and energy storage devices (supercapacitors
and batteries). Current synthetic processes for fabricating
low-defect, large-area nanofibrous structures with control-
lable fiber diameter, interconnectivity, and porosity suffer
from a number of drawbacks. These include use of volatile
organic solvents and scalability issues. Nature also pro-
duces intricate nanofibrous structures at ambient condi-
tions, such as the dense high-strength Bouligand structure
of lobster shells (composed of chitin and mineral) and wood
(composed of cellulose) or the lightweight ultrathin cuticle
of the Cyphochilus beetle. This cuticle contains a three-di-
mensional aperiodic network structure composed of chitin
fibrils around 250 nm in diameter and containing about
30% air void volume, which results in both light weight
and significant whiteness and reflectivity. The first part of
this talk will review recent work in controlling the freeze-
drying (sublimation) process to achieve fine, nanofibrous
structures that mimic those produced in nature. The sec-
152 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
ond part of this talk will take a forward-looking view of
opportunities to utilize a relatively well-established tech-
nique, supercritical drying, to produce high porosity nano-
fibrous structures from a wide range of materials. Freeze
drying has attracted intense interest as a general route to
fabricate porous materials for a wide range of applications.
Starting with a solution, emulsion, or dispersion, freezing
causes solute or solids to be excluded by an advancing
ice front into the interstitial spaces between ice crystals.
Subsequent sublimation leads to porous structures. By
controlling concentration and freezing direction, complex
hierarchical morphologies are produced, including well-
aligned channels, honeycombs, and brick-mortar-bridges
(sheet-like structures that are oriented). Because of the
large temperature gradients in common liquid-N2-based
freeze drying, most studies report oriented structures re-
sulting from fast, directional freezing. In contrast, non-di-
rectional freezing and solidification under higher freezing
temperatures, required to produce elongated fiber struc-
tures, are not well explored. For example, structures that
mimic the size and interconnectivity of the white beetle
cuticle have not been achieved by freeze drying previous-
ly. To reproduce the aperiodic nanofiber structure, we show
that freezing under higher temperature conditions (-20 °C)
reduces the temperature gradient and allows non-direc-
tional freezing. Furthermore, because chitin dispersions
readily form gels and liquid crystalline phases, we show
that slowing the ice growth velocity allows encapsulation
and preservation of networks of chitin fibers whose inter-
connectivity depend on the dispersion conditions just pri-
or to freezing. Precursor solutions or dispersions of fibers
can also be fabricated into controlled nanoarchitectures
by self-assembly or electrospinning processes, but the sol-
vent must then be removed while preserving the architec-
PANEL II: NEW MATERIALS AND MATERIALS PROCESSING 153
ture. There are drawbacks in terms of scalability and the
use of volatile organic solvents, especially in spinning pro-
cesses. Because of surface tension and interparticle at-
traction, there is potential for contraction or even collapse
of self-assembled structures during the drying step. The
second part of this talk will survey opportunities to couple
supercritical drying with existing self-assembly and spin-
ning approaches to produce high porosity nanofibrous
structures from a wide range of materials. Strengths and
weaknesses, as well as obstacles to be overcome, will be
discussed. Connections of structures to applications of
relevance to energy savings, energy production and ener-
gy storage are drawn.
MORPhOLOGy DEVELOPMENT AND PORE FORMATION IN SEMI-CRySTALLINE POLyMERS DURING CRySTALLIzATION IN CO2
155
MORPhOLOGy DEVELOPMENT AND PORE FORMATION IN SEMI-CRySTALLINE POLyMERS DURING CRySTALLIzATION IN CO2
Erdogan KiranDepartment of Chemical Engineering;
Virginia Tech, USA;
shinya TakahashiKureha Corporation, Japan
Compressed or supercritical fluids such as carbon dioxide
is of continuing interest and importance in various polymer
modifications ranging from forming particles and fibers
to foams and porous matrices. Even though polymers are
typically not soluble in carbon dioxide, carbon dioxide can
dissolve in a polymer, leading to enhanced chain mobility.
The immediate consequence of increased chain mobili-
ty is the lowering of the glass transition temperature (Tg)
and the delaying of the vitrification process, which by itself
widens the temperature range in which modifications can
be carried out. The lowering of the glass transition tempera-
ture is well documented for amorphous polymers. When
semi-crystalline polymers are involved, with dissolution of
carbon dioxide in the polymer matrix, if the melting tem-
perature (Tm) is not crossed, increased chain mobility leads
to lamellar thickening and to a recrystallized polymer which
displays a higher melting temperature and higher level of
crystallinity. This is also well documented in the literature.
If however, a semi-crystalline polymer is exposed to carbon
dioxide at temperatures where the polymer is in its molten
state, and then its recrystallization is carried out by low-
ering the temperature in the presence of carbon dioxide,
one observes lower crystallization temperatures compared
156 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
to the ambient pressure crystallization temperature from
the melt in the absence of carbon dioxide. Lowering of Tm
is also a consequence of increased chain mobility and is
well known. What is not as well-known is another phenom-
enon that occurs in crystallization from melt in the presence
of a supercritical fluid like carbon dioxide. It is the devel-
opment of unique morphologies displaying ring-banded
spherulites. These arise from the helicoidal twisting of
radial crystal lamellae and the edge-on and flat-on do-
mains leading to the observation of ring-like morphologies
when viewed under a cross-polarized optical microscope.
The banded spherulites that develop consist of concentric
ridges and valleys typically having around 100 nm vertical
distances. The ridge area is constituted of the edge-on
lamellae aligned to the radial direction of the spherulites
while the valley area is formed by flat-on lamellae. A lesser
known and explored phenomenon is the formation of pores
in the crystallization process while these morphologies
develop. Pore formation arises from exclusion of carbon
dioxide from the crystal growth fronts and its accumula-
tion in the amorphous regions in between the growing
spherulitic domains, which eventually collapse and lead
to non-spherical, oriented pores.
In this presentation, using poly (3-hydroxybutyrate-
co-3-hydroxyvalerate) (PHBV) as an example, we will ad-
dress some important questions pertaining to the assessment
of melting point depression, the influence of pressure on
the progress of crystallization and the tendency of the
system to develop banded spherulites, and on the influence
of pressure on the pore formation. PHBV is a biodegradable
semicrystalline polyester which is naturally synthesized
by microorganisms which gives them their high degree of
stereo-regularity and high purity. Low nucleation density
due to the absence of the impurities allows uncommonly
PANEL II: NEW MATERIALS AND MATERIALS PROCESSING 157
large spherulites to grow during crystallization from the
melt, which facilitate the observations of the developments
of the unique morphologies.
The presentation will emphasize the need for ex-
ploration of the lowering of the melting temperature and
recrystallization of polymers from the melt in the presence
of carbon dioxide with a new perspective. The unique mor-
phologies that develop during crystallization in CO2 that
lead to ring-banded spherulites containing pores in be-
tween needs to be explored with a fresh look as an approach
to generate nano-porous structures. The pore formation
arising from the exclusion of CO2 from the crystal growth
front, and formation of the pores in the inter-crystalline
amorphous region during crystallization raises new ques-
tions and potentially offers new opportunities with respect
to the outcomes that can be expected in supercritical fluids
which may not be limited to CO2.
PANEL PRESENTATIONS
Panel III: Green Chemistry and Sustainable Technology
MODELING ThE VOLUMETRIC AND PhASE BEhAVIOR OF CO2 SySTEMS — SUCCESSES AND ChALLENGES
161
MODELING ThE VOLUMETRIC AND PhASE BEhAVIOR OF CO2 SySTEMS — SUCCESSES AND ChALLENGES
Amyn s. TejaSchool of & Biomolecular Engineering,
Georgia Institute of Technology; Atlanta, GA 303320100, USA;
E-mail: [email protected]
The volumetric and phase behavior of CO2 systems is of
interest in a large number of green chemistry and sustain-
able technology applications, including polymer synthesis
and nanocomposite fabrication, flue gas and natural gas
processing, as well as drug encapsulation and nanopar-
ticle precipitation. Both theory and experiment suggest
that CO2 is able to interact with electron donating groups
to form weak Lewis acid-base complexes. These electron
donoracceptor or EDA complexes significantly affect the
phase behavior of CO2 systems of interest in the appli-
cations mentioned above. In spite of their importance
however, few thermodynamic models account for Lewis
acid-base interactions explicitly. There is much interest,
therefore, in thermodynamic models that incorporate weak
specific interactions, especially for systems at high pres-
sures that are typical of carbon dioxide processing.
The more successful models for associating systems
include versions of the Statistical Association Fluid The-
ory (SAFT), and several lattice fluid equations of state such
as those of Sanchez and Lacombe, and Panayiotou et al.
Although these equations of state can be used for both
phase and volumetric calculations, they generally require
self and cross-association parameters that depend on tem-
162 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
perature and/or molecular-weight. A significant amount
of experimental information is therefore required for their
use. Excess Gibbs energy models such as those of Painter,
Coleman and co-workers, on the other hand, have been
employed for describing specific chemical interactions
such as hydrogen bonds. However, these models are not
applicable to the calculation of volumetric properties. Re-
cently, two lattice models (a Compressed Lattice activity
coefficient model and an Associated Lattice Fluid equation
of state model) have been used successfully to correlate
phase equilibria and other properties in CO2 + polymer,
CO2 + cosolvent + polymer and CO
2 + ionic liquid sys-
tems over a range of pressures and temperature. These
models account explicitly for complex formation in the
lattice fluid partition function, and therefore contain phys-
ically meaningful parameters that are independent of tem-
perature or pressure. Moreover, it will be shown that in
situ Attenuated Total Reflection Fourier Transform Infrared
(ATR FTIR) measurements or CO2 absorption data can be
used to obtain one of the parameters in these models, with
experimental phase equilibrium data being used to obtain
the remaining adjustable parameter.
The application of the Compressed Lattice activity
coefficient model will be demonstrated by calculating both
cloud points and sorption equilibria in CO2 + PVAc and
CO2 + PLGA systems using a single adjustable parameter.
It will be shown that calculated equilibria are in good
agreement with measured values confirming that the mod-
el is able to extrapolate phase equilibrium data over a
range of pressures. It will also be shown that sorption
equilibria in CO2 + PLGA systems can be predicted using
information obtained from FTIR spectra and a single pa-
rameter obtained by fitting cloud point pressures in a ref-
erence system (CO2 + PLA in our case). This demonstrates
PANEL III: GREEN ChEMISTRy AND SUSTAINABLE TEChNOLOGy 163
that the model is capable of extrapolating information to
systems that have common functional groups. The depres-
sion of the glass transition temperature in the CO2 + PLA
system was also predicted without any additional param-
eters, demonstrating that the model can be used to predict
other properties. However, the compressible lattice mod-
el is inherently incapable of predicting volumetric prop-
erties.
This limitation has led to the development of the
Associated Lattice Fluid Equation of State model that is
able to calculate both phase equilibria and volumetric
properties. The EOS contains two mixture parameters —
the enthalpy of association ∆Ha and the equilibrium con-
stant at a reference temperature K0 — which do not depend
on temperature, pressure or molecular weight. The solu-
bility of CO2 in a number of polymers was correlated over
a wide range of temperatures and pressures using ∆Ha
values from independent FTIR measurements and K0val-
ues obtained by fitting solubility data. It is shown that the
new model is able to correlate solubility data within ex-
perimental error (maximum AAD of about 4%). In addition,
the extent of swelling of these polymers by CO2 can be
predicted without any adjustable parameters. The ALF EOS
therefore shows considerable promise in calculating both
phase equilibrium and volumetric data of CO2 systems.
Finally, the performance of these models in calcu-
lating phase equilibria and other properties of CO2 systems
will be used to identify future directions and challenges
in the modeling of such systems.
NANOPARTICLE SyNThESIS AND PROCESSING USING TUNABLE FLUIDS
165
NANOPARTICLE SyNThESIS AND PROCESSING USING TUNABLE FLUIDS
christopher L. KitchensDepartment of Chemical and Biomolecular Engineering,
Clemson University, USA;E-mail: [email protected]
Advancements in nanotechnology have led to a wide-
spread emergence of different techniques for nanoparticle
synthesis and application. The size and shape dependent
properties of nanomaterials motivate different synthesis
methodologies that afford morphological control. For cases
where morphology control is not afforded, monodispersed
populations of nanomaterials can be obtained by post-syn-
thesis fractionation based on size or shape. These frac-
tionation techniques are typically very solvent and energy
intensive as well as limited in scalability. A vital and often
overlooked component in the nanotechnology field is the
development of efficient, reduced-cost, and large-scale
methods for nanoparticle synthesis and processing. In re-
cent years, significant advancements have been made in
nanomaterial synthesis, processing, and application using
tunable fluids that provide promising alternatives to con-
ventional methods. Tunable fluids are a unique class of
fluids where the solvent’s thermophysical properties (eg.
solvent strength, density, diffusivity, interfacial tension)
can be tailored by controlling the system temperature and
pressure. Examples of tunable fluids are supercritical flu-
ids (SCFs), near-critical fluids (NCFs) and gas expanded
liquids (GXLs). For the first two, the temperature and pres-
sure of the system are either close to (NCFs) or above (SCFs)
166 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
the solvent’s critical point. In this region, the solvent prop-
erties are intermittent between those of a liquid and of a
gas; possessing the increased solvent strength and ther-
mal conductivity of a liquid along with the diffusivity of a
gas. Furthermore, the solvent is highly compressible under
these conditions, which enables control of these properties
by simply changing the pressure; hence the name tunable
fluids. GXLs consist of a gas and liquid mixture at pres-
sures below the vapor pressure of the gas phase. The tun-
able properties of GXLs rely on the high solubility of gasses
in liquids where the composition of the mixture is con-
trolled by the partial pressure of the gas phase. For exam-
ple, CO2 expanded hexane at 49 bars of CO
2 partial pressure
is 80 mol % CO2 and exhibits a volume expansion of near-
ly three times the hexane volume at ambient pressure. At
58 bar and 25 °C, the liquid phase is 91.3 mol % CO2, thus
a wide range of solvent properties can be achieved by
simply changing the CO2 partial pressure over a moderate
operating pressure range. The GXL liquid component can
consist of virtually any non-aqueous solvent, which imparts
a wide range of tunable fluid properties. Because the GXL
consists of a liquid solvent and a dissolved gas, the ther-
mophysical properties are again intermittent between the
two but at a much reduced pressure. This presentation
will review recent work in the synthesis and processing
of metal and metal oxide nanoparticles in each of these
tunable fluids; NCFs, SCFs, and GXLs. Specific topics will
include:
� Surfactant-mediated metal nanoparticle synthesis
in SC CO2 and CO
2 expanded liquids where the
tunable solvent properties govern the nanoparticle
synthesis.
PANEL III: GREEN ChEMISTRy AND SUSTAINABLE TEChNOLOGy 167
� Metal oxide nanoparticle synthesis in near critical
and supercritical water.
� Post-synthesis purification and size-selective frac-
tionation of nanoparticles in GXLs.
� Uniform deposition of nanoparticles into wide-area
arrays using GXLs.
� Development of a thermodynamic interaction en-
ergy model to predict nanoparticle dispersibility as
a function of the tunable solvent properties.
� Small angle neutron scattering (SANS) measure-
ment of nanoparticle ligand shell thickness, solva-
tion, and degree of surface coverage in GXLs.
For nanoparticle synthesis, the solvent properties
influence the nanoparticle nucleation, growth, and stabi-
lization, which results in control over the nanoparticle size
and polydispersity. For polydispersed populations of nano-
materials, GXLs provide a novel medium for size and shape
selective fractionation, where particle dispersibility is a
function of the CO2 partial pressure. For example, dodec-
anethiol-stabilized gold nanoparticles are easily dispersed
in hexane. The progressive addition of CO2 to the hexane
will induce size-selective precipitation where the largest
nanoparticles precipitate at lower CO2 partial pressures
and the smaller nanoparticles precipitate at higher pres-
sures. This is akin to conventional liquid anti-solvent pre-
cipitation methods with the two notable exceptions: (1)
following fractionation, the pressure can be released and
all of the original solvents can be recovered, eliminating
the significant amounts of solvent waste and (2) the in-
creased nanoparticle diffusivity eliminates the need for
centrifugation which reduces the energy requirement and
facilitates the potential for large scale application.
168 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
Many nanomaterial applications require uniform
deposition of nanoparticles onto a surface. Conventional
solvent-based methods can result in non-uniformities from
interfacial drying effects or require slow volatilizing sol-
vents. For SCFs, spray applications are possible. For GXLs
the CO2 pressure can be increased beyond the vapor pres-
sure and then heated beyond the critical point before re-
leasing the pressure, enabling critical point drying and
preservation of the nanoscale structure. For each of these
applications, a fundamental understanding of the un-
derlying thermodynamics behind the nanoparticle dis-
persibility facilitates our ability to produce well-defined
nanomaterials for a diversity of applications in a sustain-
able manor.
REFERENCES
f Hart et al., J. Supercritical Fluids, 79 (2013) 236-243.
f Von White II et al., Industrial & Engineering Chemical Research, 51(14)
(2012) 5181-5189.
f Von White II et al., J. Physical Chemistry C, 114(39) (2010) 16285-16291.
f Anand et al., Industrial & Engineering Chemical Research, 47(3) (2007)
553-559.
f McLeod et al., Langmuir, 21(6) (2005) 2414-2418.
f McLeod et al., Nano Letters, 5(3) (2005) 461-465.
f Kitchens et al., Industrial & Engineering Chemical Research, 43(19)
(2004) 6070-6081.
GREEN PROCESSES FOR hIGh ADDED-VALUE PRODUCTS ExTRACTION FROM NATURAL SOURCES
169
GREEN PROCESSES FOR hIGh ADDED-VALUE PRODUCTS ExTRACTION FROM NATURAL SOURCES
E. ibáñez Instituto de Investigación en Ciencias de la Alimentación
CIAL (CSIC-UAM); C/Nicolás Cabrera 9, Campus de Cantoblanco,
28049 Madrid, España; E-mail: elena@ifi .csic.es
At present, there is an enormous interest in trying to give
new answers to one of the main societal challenges in our
society: that is, sustainability. Sustainability can be under-
stood as a rational way of improving processes to maximize
production while minimizing the environmental impact
or, in the words of the Environmental Protection Agency
(EPA), “sustainability creates and maintains the conditions
under which humans and nature can exist in productive
harmony, that permit fulfilling the social, economic and
other requirements of present and future generations”.
Bearing this in mind, many aspects can be considered in
this framework, ranging from the rational use of resources
to the modern concept of biorefinery which, undoubtedly,
may change our perception of the industrial processes in
this century. Considering this framework, the production
of valuable products from natural sources is of high inter-
est since it can allow to consolidate the idea of sustainable
processes.
In the area of food science and nutrition, the finding
of new bioactive compounds able to prevent or improve
the health status of the individuals, mainly acting as food
supplements or functional food ingredients, is of upmost
importance nowadays. Considering the tremendous mar-
170 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
ket value of the functional food industry, it is easy to un-
derstand the enormous interest in new compounds, extracts
and products that, once its efficacy has been proved with
scientific evidences, should be produced at large scale. A
good example of this are, for instance, compounds such
as antioxidants, associated to lower risk of certain diseas-
es that are nowadays widespread in the developed coun-
tries, such as coronary heart diseases and cancer [1,2].
Although they have been investigated in the last years
and some of them have provided with evidence about their
effect, much more research is needed to prove their real
efficacy in human beings. Undoubtedly, nature can be con-
sidered an unlimited source of bioactives and the search
of new compounds with improved activities have ran par-
allel to the search for new natural sources. It is well known
that there are many families of compounds with proved
antioxidant activity, such as phenolic compounds, carot-
enoids and tocopherols, which are easily available in the
vegetal kingdom. But at present there is a huge interest
in the potential use of marine natural sources to obtain
these bioactives, mainly considering their huge diversity,
in terms of number of different species that might be po-
tentially used, their sometimes unique chemical structures
and their ability to work as natural bioreactors potentiat-
ing the synthesis of valuable compounds depending on
the cultivation conditions. Moreover, the biorefinery con-
cept has been recently associated to algae as one of the
most sustainable ways to improve the efficient use of algae
biomass [3].
Moreover, researchers are facing new challenges
in the development of new extraction processes to obtain
valuable products from natural sources. Up to now, tradi-
tional extraction methods (mainly S-L extraction) have
been used to extract bioactives; these methods have sev-
PANEL III: GREEN ChEMISTRy AND SUSTAINABLE TEChNOLOGy 171
eral drawbacks like they are time consuming, laborious,
have low selectivity and/or low extraction yields. New
challenges involve the development of fast, selective, ef-
ficient, sustainable, green (without using toxic organic
solvents), with high yields and at lower cost. The tech-
niques able to meet these requirements are, among others,
those based on the use of compressed fluids such as su-
percritical fluid extraction (SFE), pressurized liquid ex-
traction (PLE) and subcritical water extraction (SWE), which
are among the more promising processes [4, 5]. Depending
on the polarity of the green compressed fluid, different
“green” or environmentally clean technologies can be used,
as can be seen in Figure 1.
high polarityWater Pressurized solvents
SWE, PLE
Medium polarityPressurized solventsscCO2 + polar modifiers (EtOH)Gas Expanded Liquids
PLE, SFE, GXL
Low polarityscCO2
LimonenePLE, SFE
Figure 1. Green solvents and environmentally friendly technologies used
to extract high added-value products from natural sources
In this presentation, different examples will be
shown, considering different raw materials such as plants,
algae and food by-products and employing the above men-
tioned green technologies. With this approach we will try
to demonstrate the possibility of tuning the extraction con-
ditions depending on the target compound(s) and the raw
material to achieve sustainable processes.
172 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
Among other examples, some research works devel-
oped in our laboratory will be presented dealing with the
direct extraction, using SFE (Supercritical Fluid Extraction),
of carotenoids (astaxanthin) from Neochloris oleoabundans
biomass; the isolation, using gas expanded liquids (GXLs),
of gamma-linolenic acid from Spirulina; the extraction of
antioxidants from rosemary using integrated processes
of extraction and particle formation (WEPO, Water Extrac-
tion and Particle formation On-line); and the use of LCA
(Life Cycle Assessment) tool to evaluate the environmen-
tal impact of different green extraction processes (SFE,
SWE, WEPO).
ACKNOWLEDGMENTS
This work was financed thanks to AGL2011-29857-C03-01 (Ministerio de
Economía y Competitividad) and ALIBIRD, S2009/AGR-1469 (Comunidad
de Madrid) projects.
REFERENCES
[1] A. Harris, S. Devaraj, I. Jialal, Oxidative stress, alpha-tocopherol thera-
py, and atherosclerosis, Current Atherosclerosis Reports, 4(5) (2002)
373-380.
[2] R. Brigelius-Flohe, F.J. Kelly, J. T. Salonen, J. Neuzil, J-M Zingg, A. Azzi,
The European perspective on vitamin E: current knowledge and future
research, The American J. Clinical Nutrition, 76(4) (2002) 703-716.
[3] E. Ibañez, A. Cifuentes, Benefits of using algae as natural sources of
functional ingredients, J. Science of Food and Agriculture, 93 (2013)
703-709.
[4] M. B. King, T. R. Bott, Extraction of natural products using near-critical
solvents; Blackie Academic & Professional, Glasgow, 1993.
[5] J. A. Mendiola, M. Herrero, A. Cifuentes, E. Ibáñez, Use of compressed
fluids for sample preparation: Food applications, J. Chromatography
A, 1152(1-2) (2007) 234-246.
SCIENTIFIC PRODUCTION OF SUPERCRITICAL FLUID TEChNOLOGy WORLDWIDE: ROLE OF ACADEMIA
173
SCIENTIFIC PRODUCTION OF SUPERCRITICAL FLUID TEChNOLOGy WORLDWIDE: ROLE OF ACADEMIA
socrates Quispe-condoriSchool of Food Engineering, Universidad Peruana Unión;
Alt. Km 19 Carretera Central, Ñaña, Lima, Peru; E-mail: [email protected]
Since benefits of supercritical fluids were recognized in
the 70’s, extensive research have been carried out on their
potential applications (supercritical fluid extraction, en-
ergy applications, analytical applications, supercritical
water oxidation, supercritical fluid fractionation, super-
critical fluid reactions, applications in material science,
cleaning technology, fine particle production, encapsula-
tion, foaming, green chemistry / engineering, sustainabil-
ity / bioenergy / biomass, blending in supercritical media,
polymerization / copolymerization, catalysis, material syn-
thesis, drying, distillation, and crystallization) by several
research groups. Although some of the technologies were
implemented at industrial and commercial scales, scien-
tific literature often presents new applications of super-
critical fluids. Many reviews were presented about the
progress of supercritical fluid technology in different areas.
However, there are no references related to the analysis
of scientific production in this technology. Scientific pro-
duction is one of the critical factors for country develop-
ment. Studies related to the production of information allow
to evaluate the scientific activity and its development,
identifying significant trends, characterizing representa-
tive institutions, scientific working groups and research
174 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
topics. Bibliometrics, when applying statistical methods,
enables the analysis of scientific production from literature
sources, determining the research activity in a quantita-
tive way. During the last decades, bibliometrics has been
applied in all knowledge areas, usually through descriptive
reports.
The objective of this work is to determine scientif-
ic production of the applications of supercritical fluids
through a descriptive bibliometric analysis. The publica-
tion of articles, reviews, books and conference manuscripts
from all countries were analyzed, giving special attention
to the participation of academia in the development and
diffusion of this technology, evaluating its production in
terms of its international impact, and identifying the most
productive scientific institutions. Scientific production was
evaluated in the Scopus database (www.scopus.com). Sco-
pus is the largest database of scientific literature, covering
all areas of science, technology, medicine, social sciences
and arts & humanities. Currently, it contains a record of
approximately 50 million bibliographic references from
21000 titles and 5000 publishers. “Supercritical” term in
Title field was used as search strategy in the database.
The following bibliometric indicators of productivity were
determined: Documents per year (from 1970 to September
2013), document type, scientific production by country,
distribution for knowledge areas, number of papers per
author, and publications for journals. Macro trends that
guided the development of supercritical fluid technology
in countries and institutions were identified.
The total number of reported references in Scopus
database were 26 923, distributed in Articles (77.20%), Con-
ference Papers (15.86%), Reviews (4.42%), Articles in Press
(0.54%), Books (0.23%) and Conference Review (0.23%). It
is observed that United States (19.51%), China (16.68%),
PANEL III: GREEN ChEMISTRy AND SUSTAINABLE TEChNOLOGy 175
Japan (10.39%), Germany (4.70%) and France (4.38%) have
the best indicators in terms of production of scientific
articles. Development indicators of science in terms of
publications in Latin America are farther away from the
standards of countries with the highest scientific and tech-
nological development. Brazil (1.75%), Argentina (0.42%)
and Colombia (0.16%) are the most productive. Regarding
the field of application, it was observed that scientific
production is oriented at Chemistry (22.23%), Chemical
Engineering (16.28%), Engineering (12.10%), Materials
Science (11.98%), Physics and Astronomy (10.28%), Ener-
gy (6.20%), Environmental Science (4.97%), Biochemistry,
Genetics and Molecular Biology (4.66%), Agricultural and
Biological Sciences (3.36%), and Pharmacology, Toxicolo-
gy and Pharmaceutics (2.15%). Main sources of diffusion
of scientific production are Journal of Supercritical Fluids
(14.67%), Industrial and Engineering Chemistry Research
(5.24%), Journal of Chromatography A (4.43%), Fluid Phase
Equilibria (3.67%) and Journal of Chemical and Engineer-
ing Data (2.15%). Universities are the leading scientific
productive institutions compared to the research centers.
Institutions with highest scientific production are Tohoku
University (1.36%), University of Tokyo (1.11%), Kyoto Uni-
versity (0.99%), Tsinghua University (0.83%) and Zhejiang
University (0.82%). The research center with highest sci-
entific production is the National Institute of Advanced
Industrial Science and Technology (1.11%).
MODELING OF SUPERCRITICAL CARBON DIOxIDE ExTRACTION OF JATROPhA (JATRophA cuRcAs L.) SEEDS
177
MODELING OF SUPERCRITICAL CARBON DIOxIDE ExTRACTION OF JATROPhA (JATRophA cuRcAs L.) SEEDS
suzana yusup, Vladan Mićić, yi herng chanUniversiti Teknologi PETRONAS;
Bandar Seri Iskandar, 31750, Tronoh, Perak, Malaysia; E-mail: [email protected]
This work investigates the extraction of Jatropha seeds
utilizing supercritical carbon dioxide. The yield of the ex-
traction increased with time and the extraction process
can be clarified into slow and fast extraction region. In the
modelling of the supercrital extraction process, Rever-
chon-Sesti Ossea model and its modified form were used
to compare with the experimental extraction yield and
both models were found to be in good agreement with the
process.
ORGANOCATALySIS IN SUPERCRITICAL CO2: A NEW EFFICIENT CATALyST FOR ASyMMETRIC ALDOL REACTIONS
179
ORGANOCATALySIS IN SUPERCRITICAL CO2: A NEW EFFICIENT CATALyST FOR ASyMMETRIC ALDOL REACTIONS
Reinaldo BazitoInstituto de Química,
Universidade de São Paulo (USP); Av. Prof. Lineu Prestes, 748-B8T, Sala 811, Cidade Universitária,
05508-000 São Paulo, SP, Brazil; E-mail: [email protected]
The enantiomers of a chiral compound have identical
chemical properties but may present different biological
action. There are many examples where one of the enan-
tiomers is a very effective drug while the other is not as
effective or may even be toxic. This has lead to extensive
research on synthetic methodologies to produce a single
enantiomer for target molecules containing stereogenic
centers (enantioselective or asymmetric synthesis), spe-
cially using catalysis.
Two major approaches have been used for asymet-
ric synthesis: asymmetric catalysis, where the catalyst is
usually a chiral transition metal complex; or biocatalysis,
where the catalyst is an enzyme. A new approach, how-
ever, started to gain importance recently, the asymetric
organocatalysis, where the catalyst is a small chiral or-
ganic molecule added to the reaction media in substoi-
chiometric quantities. These molecules can be natural
chiral compounds from the “chiral pool”, such as amino
acids, alkaloids, sugars and so on, providing a greener
approach to enantioselective synthesis.
The Aldol condensation is a very important reaction
in organic synthesis, with its asymmetric version being
used to form a new carbon-carbon bound in an enantiose-
180 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
lective way. Organocatalysis using chiral amino acids,
especially L-proline, have been successfully employed for
this reaction, providing a greener catalyst, but there are
still some drawbacks, including a high E factor (high waste/
product ratio), mainly due to the use of organic solvents
and the need to neutralize the base used in stoichiometric
quantities, and long reaction times. New reaction media
that could improve selectivity/yield, with shorter reaction
times and reduced waste generation are being sought for.
Supercritical carbon dioxide is one of these possible
new reaction media, because of its unique properties: an
environmentally benign solvent with accessible critical
point (Tc = 304.2 K, Pc = 7.38 MPa), very good transport
properties, unique phase behavior, among other interest-
ing properties. The combination of this neoteric solvent
with organocatalysis for the Aldol condensation reaction
is very promising and was the subject of this work.
Our group has recently studied a series of proline
derivatives for the organocatalysis of Aldol type reactions
in sc-CO2 or a combination of this solvent with an imidaz-
ole-based ionic liquid (1-allyl-3-alkyl-imididazolium chlo-
rides).
The first Aldol reaction to be studied was the con-
densation reaction between acetone and 4-nitrobenzalde-
hyde, resulting in a β-hydroxy ketone (as the chiral addition
product) and a α,β-unsaturated ketone (as the undesired
achiral elimination product). The catalysts employed for
this reaction were L-proline, used as a standard, and the
following L-proline derivatives: (R)-thiazolidine-4-carbox-
ylic acid (thio-L-proline); (2S,4R)-4-(dimethyl(phenyl)silyl)
oxy-pyrrolidine-2-carboxylic acid (dimetilphenylsilyloxy- L-
proline); (2S,4R)-4-(tert-butyldimethylsilyloxy)pyrrolidine-
2-carboxylic acid (t-butyl-dimetilsilyloxy-L-proline); (2R,3R,
4R,5R,6S)-2-(acetoxymethyl)-6-(pyrrolidine-2-carboxamido)
PANEL III: GREEN ChEMISTRy AND SUSTAINABLE TEChNOLOGy 181
tetrahydro-2H-pyran-3,4,5-triyl triacetate (peracetyl-glucos-
amine-L-proline). The influence of pressure, temperature,
presence of ionic liquid and type of catalyst were evaluated.
The best results were obtained with one of the si-
lylated catalysts, tert-butyldimethylsilyloxy-L-proline, with
very good yields and enantiomeric excesses (e.e.) of the
product, in shorter reaction times, especially in the pres-
ence of the ionic liquid. Yields around 54%, with enan-
tiomeric excess around 79%, could be obtained in 2 h of
reaction, at 150 bar and 40 oC.
Another Aldol reaction that have been studied is
the condensation reaction between cyclohexanone and
4-nitrobenzaldehyde, using as catalysts L-proline (as a
standard), t-butyl-dimetilsilyloxy-L-proline, and a helicoidal
polyacethylene containg L-proline groups, resulting in the
chiral anti/syn addition product. The influence of reaction
time and the presence of additives (acetic acid or ionic
exchange resin) were investigated, for the same pressure
and temperature used for the previous reaction (150 bar,
40 oC).
Both catalysts were more effective than L-proline
resulting in higher yields and enantiomeric excesses in
shorter times. The best results were obtained with the
tert-butyldimethylsilyloxy-L-proline catalyst, using ion ex-
change resin, with an isolated yield of 71% and an e.e. of
91% (for the anti product).
The proline derivatives were effective organocata-
lysts for the Aldol reactions in sc-CO2, specially the silylat-
ed derivative, presenting shorter reactions times than in
organic solvents and good yields and enantiomeric ex-
cesses.
PhyTOChEMICAL PRODUCTION FROM BIOMASS USING PRESSURIzED FLUIDS
183
PhyTOChEMICAL PRODUCTION FROM BIOMASS USING PRESSURIzED FLUIDS
Marleny D. A. saldañaDepartment of Agricultural, Food and Nutritional Science,
University of Alberta; Edmonton, Alberta, T6G 2P5, Canada;
E-mail: [email protected]
Pressurized fluids, such as subcritical water, pressurized
aqueous ethanol and supercritical CO2 (scCO
2) are consid-
ered green and environmentally friendly solvents that can
be used for production of phytochemicals from a variety
of Canadian biomasses as well as for various reactions.
Phytochemicals, such as phenolic acids are found in var-
ious biomasses as hydroxybenzoic and hydroxycinnamic
acids. These compounds have antioxidant and antimicro-
bial activities and their consumption have been correlat-
ed with a lower incidence of cancer, heart disease, and
diabetes. Carbohydrates are also considered important
phytochemicals that can be used in a number of food,
pharmaceutical and fuel applications. Research in my lab-
oratory has focused on solubility determination of select-
ed phenolic acids and sugar compounds in pressurized
water as well as the use of pressurized fluids to obtain
these phenolics and carbohydrates from biomasses, such
as potato peel, lentil husk, and barley hull, among others
to later be used in various applications. For solubility of
selected phenolic acids and selected sugars in pressurized
water, experimental data were obtained at pressures of
15-120 bar and temperatures of 100-180˚C using a dynam-
ic flow high pressure system. The results obtained showed
184 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
that the solubility of sugars (glucose and lactose) in pres-
surized water increase with an increase in temperature.
However, with the increase of pressure from 15 to 120 bar,
the solubility of both sugars in pressurized water decreased.
For selected phenolic acids, solubility was affected by
temperature. Dissolution of selected phenolic acids in
pressurized water increase, remain stable (gallic acid) or
decreased (3-4-hydroxyphenyl propionic acid and 4-hy-
droxybenzoic acid) with an increase of temperature. Pres-
sure influenced aqueous solubility of gallic acid from 100
to 150˚C, but had no effect on the solubility of the other
phenolic acids selected in the temperature interval stud-
ied. Experiments of phenolics and carbohydrates removal
of selected biomasses using pressurized fluids were per-
formed using a dynamic flow high pressure system at dif-
ferent temperatures ranging from 100 to 260˚C, pressures
up to 200 bar and times up to 180 min. Other variables
evaluated for selected biomass systems were static hold-
ing time and pH. Then, experiments of enzymatic synthe-
sis of selected phenolic compounds in oil in scCO2 media
were performed in a laboratory-scale supercritical fluid
system at different temperatures ranging from 40 to 80˚C,
pressures from 4 to 350 bar and time up to 53 h. In addition,
the use of selected phenolic compounds in milk was eval-
uated at temperatures of 60-120˚C, pressures of 1000-6000
bar and times up to 15 min. Extracts and residues obtained
after biomass treatment using pressurized fluids were eval-
uated for their individual concentrations of phenolic and
carbohydrate compounds, total phenolic and carbohydrate
contents, and antioxidant activity. Results indicated that
the total phenolic and carbohydrate contents and antiox-
idant activity increased with temperature. The highest
total carbohydrates, total phenolics, and total antioxidant
activity of each biomass were obtained at optimized con-
PANEL III: GREEN ChEMISTRy AND SUSTAINABLE TEChNOLOGy 185
ditions of pressure, temperature and static holding time
using pressurized fluids. For example, the highest carbo-
hydrate extraction (576.1±19.1 mg/g hull) from barley hull
was obtained using pressurized aqueous ethanol with low
ethanol concentration (12%, v/v), but this pressurized flu-
id was not the best for phenolics removal. For the applica-
tions, results have shown that scCO2 is a promising green
solvent for the enzymatic synthesis of phenolic lipids. In
addition, the use of selected phenolic acids in milk retained
valuable components while inactivating spores (Bacillus
amyloliquefaciens) and the alkaline phosphatase enzyme
using high pressure processing assisted by temperature.
Phytochemical production from selected biomasses using
pressurized fluids and its uses in reactive system applica-
tions were demonstrated.
PANEL PRESENTATIONS
Panel IV: SCFs as Working Fluids / Process Technology and Design
SyNThESIS AND POWDER GENERATION OF POwDER COATINGS USING SUPERCRITICAL CARBON DIOxIDE
189
SyNThESIS AND POWDER GENERATION OF POwDER COATINGS USING SUPERCRITICAL CARBON DIOxIDE
i. Bochon, M. petermannUniversity Bochum;
Universitaetsstr. 150, 44801, Bochum, NRW, Germany; E-mail: [email protected]
The use of powder coatings is a promising way to reduce
organic solvents emission, as the application of such coat-
ings is completely emission free. Unfortunately the syn-
thesis of powder coating components is classically made
with organic solvents, which is leading to emissions in the
manufacturing step. Powder coatings consist of two main
components, a binder and a hardener, which can be cross-
linked via a chemical reaction, induced by heat or radia-
tion. Beside these polymeric main components, additives
like pigments, fillers, degassing agents etc. have to be
added. To manufacture powder coatings different indus-
trial steps are necessary. First the polymers have to be
synthesized and granulates have to be formed. In a second
step the polymers and the other components have to be
homogenized in drum mixers. This mixture is melted, rolled
to a plate, solidified and later broken into flakes. These
flakes have to be ground to the final powder coatings. For
this step, air-jet mills are used to gain powders with av-
erage particles sizes of 30-40 micrometers. Overall the
classical powder coating manufacturing process is time,
energy and cost intensive and additional solvent emissions
have to be accepted during polymer synthesis. The aim of
this work is to substitute the classical multi-step process
with a single continuous process, using supercritical car-
190 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
bon dioxide as auxiliary media. In a first step the synthe-
sis of the polymer is made in supercritical CO2 and, by
adjusting the process parameters can be done in a single
phase regime. This is leading to high space-time yields.
The synthesis of a powder coating binder in supercritical
CO2 was first published by Beuermann et al. [1,2] In a
second step, without depressurization, the additional com-
ponents of a powder coating have to be added — mainly
the hardener component. A surplus of carbon dioxide is
leading to a further reduction of the polymer viscosity and
is easing the spray of such mixtures. To form the final pow-
der coating, the so called PGSS (particles from gas satu-
rated solutions) process is used [3]. In this process, a gas
saturated mixture is expanded via a nozzle into a spray
tower. The pre-expansion pressure is lying in the area of
20 MPa and the pre-expansion temperature is slightly
above the melting point of the components. During the
expansion, the dissolved gas is set free and is leading to
a fine droplet formation. Additionally, the gas cools down,
caused by the Joule-Thomson effect. Due to the cooling,
the droplets solidify and a powder coating is formed. The
expansion can be additionally used for the cleaning of the
polymers. Residue monomers, left over after the reaction
can be stripped away by the expanding gas. The super-
critical fluid process is characterized by a single step de-
sign and is leading to no solvent emission. The contribution
will first illustrate the optimization of the polymer reaction
of the binder component in supercritical fluids. These ex-
periments were carried out first in a batch reactor and
later in a continuous tubular reactor. In a second part the
continuous single step process will be illustrated. This
plant consists of the tubular reactor and a PGSS plant for
the particle generation. The reactions carried out in com-
pressed CO2 are characterized by high yields of 80-90%,
PANEL IV: SCFS AS WORKING FLUIDS / PROCESS TEChNOLOGy AND DESIGN 191
short reaction times of about 20 minutes and a small
polydispersity of PDI ≤ 2 of the synthesized polymer. The
experiments show that the targeted average molecular
weight of Mn ≈ 2500 g/mol can be reached in presence
of the compressed gas. The contribution will end with
ready-made powder coatings, gained with a plant, which
is combining the tubular reactor with the expansion step
of the PGSS plant and is leading to particle systems which
have mean particle sizes, suitable for powder coating ap-
plications.
REFERENCES
[1] S. Beuermann, M. Buback, C. Isemer, A. Wahl, Homogeneous free-
radical polymerization of styrene in supercritical CO2, Macromolecular
Rapid Communications, 20(1) (1999) 26-32.
[2] S. Beuermann, M. Buback, M. Jürgens, Free-radical terpolymerization
of styrene and the two methacrylates in homogeneous phase con-
taining supercritical CO2, Industrial Engineering Chemistry & Research,
42(25) (2003) 6338-6342.
[3] E. Weidner, M. Petermann, K. Blatter, V. Rekowski, Manufacture of
Powder Coatings by Spraying of Gas-Enriched Melts, Chemical Engi-
neering & Technology, Wiley-VCH, Weinheim, (24) (2001) 529-533.
SUPERCRITICAL CO2 AS WORKING FLUID IN ThE NATURAL GAS INDUSTRy
193
SUPERCRITICAL CO2 AS WORKING FLUID IN ThE NATURAL GAS INDUSTRy
christopher g. spilsburyBG Group, Thames Valley Park;
RG6 1PT, Reading, Berkshire, UK; E-mail: [email protected]
The Natural Gas industry represents a potential opportu-
nity in the application of supercritical carbon dioxide as
a working fluid for the efficient transport of natural gas.
This is the subject of this perspective. The goal of many
companies such as the BG Group is to reduce the carbon
footprint of business operations and improve efficiency.
BG Group is seeking to improve efficiency of its operations
at a rate of 2% per annum. The natural gas industry makes
extensive use of large gas compressors, some as large as
50 MW and more. These gas compressors are used for
many duties including pipeline gas compressors and re-
frigerant gas compressors used in gas liquefaction plants
(LNG). Many of these gas compressors are driven by gas
turbines. The industry also uses gas turbine driven gen-
erator sets, often to generate the electricity used on remote
gas production and gas processing facilities. The BG Group
itself has more than 100 gas turbine driven machines dis-
tributed across it assets. Gas turbine driven equipment is
used in both an onshore and offshore environment. Many
of these gas turbines are installed as simple open cycles
without waste heat recovery. To date this has been for
many reasons including how to utilise the exhaust waste
heat effectively and in some case space and weight con-
straints. Supercritical CO2 applied to energy recovery from
194 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
these gas turbine exhausts has great potential. A super-
critical CO2 brayton or rankine cycle for energy recovery
could recover the heat to electrical energy or motive pow-
er for the gas compressors. These cycles are potentially
as efficient as steam cycles, simpler than steam or organ-
ic rankine cycles, use a safe working fluid and have po-
tentially the lowest space requirement. There is potential
to utilise supercritical CO2 as a component in providing
highly efficient local solution for gas industry driven equip-
ment without the need for extensive power and heat dis-
tribution systems with their associated energy losses. For
those gas turbine in the BG Group there is potential to
recover over 1 GW of power. There is a significant role that
supercritical CO2 as working fluid could play in improving
the industry efficiency. With typical machine duties in the
range of 5 to 50 MW the industry utilises of machines of
an ideal size to develop and demonstrate supercritical CO2
technology. The gas industry continues to grow with in-
vestment in new pipelines, compression systems and gas
liquefaction facilities providing opportunity for investment
in heat recovery using supercritical CO2 as working fluid.
There are technical challenges for this technology in the
size range being considered, particularly in the CO2 ex-
pansion turbine design. The compactness of supercritical
CO2 may make this the future technology of choice for
energy recovery on offshore installations to make these
installations the most energy efficient. It is very possible
that mechanical work derived from the supercritical CO2
turbines may be integrated to supplement the mechanical
power of the gas turbine prime mover in one highly effi-
cient package. One day we might see a mechanical driv-
er package with a combined efficiency of over 55%. The
natural gas industry has an opportunity to play a signifi-
cant role in the development and implementation of su-
percritical CO2 power systems.
hyDROCARBON GROUP SEPARATION USING SUPERCRITICAL CO2: ThE LAST 20 yEARS AND ThE FUTURE AT PETROBRAS R&D CENTER
195
hyDROCARBON GROUP SEPARATION USING SUPERCRITICAL CO2: ThE LAST 20 yEARS AND ThE FUTURE AT PETROBRAS R&D CENTER
flávio c. Albuquerque, Arthur de Lemos Scofi eld,
Marcos vinícius Riscado cabralCENPES – PETROBRAS R&D Center;
Av. Horácio de Macedo, 950, Cidade Universitária, 21941-915, Rio de Janeiro, RJ, Brazil;
E-mail: [email protected]
M. Angela A. MeirelesLASEFI/DEA/FEA (School of Food Engineering),
UNICAMP (University of Campinas);R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil
Fossil fuels are complex mixtures constituted by hydro-
carbons and N,S,O-compounds as contaminants, with a
wide distillation range. The complete separation of these
mixtures in the individual constituents is feasible only for
the lighter fractions, using high resolution analytical tech-
niques, like 1D- and, more recently, 2D-gas chromatogra-
phy. To analyze the whole crude oil or its heavier fractions,
group separation according to the chemical nature of their
components is usually required. The determination of hy-
drocarbon families, such as saturated hydrocarbons, ole-
fins, diolefins, and hidrocarbons according to the number
of aromatic rings is essential for the petroleum industry
in many situations. Although fairly simple, considering the
huge number of components, it provides enough informa-
tion to evaluate quality of crude oil or fuels, to infer about
their stability, or to optimize refining processes and cata-
lysts. Unfortunately, most of these analyses, usually per-
formed by normal phase liquid chromatography or solid
phase extraction, suffer with different drawbacks. To cir-
196 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
cumvent the lack of a universal detector for liquid chro-
matography, separations have sometimes to be performed
through preparative procedures, which are often lengthy
and lead to loss of lighter components. The choice of an-
alytical-scale liquid chromatography with the refraction
index detector is restricted to the analysis of narrow dis-
tillation cuts or products, due to differences in the response
factors of the components.
In the mid of 80’s there was a rebirth of supercriti-
cal fluid chromatography (SFC), which promised faster and
more efficient separations than high-performance liquid
chromatography. By the beginning of 90’s, ASTM approved
D 5186 standard, for determination of mononuclear and
polynuclear aromatic hydrocarbon contents in diesel fuels
by SFC. The usage of polar stationary phase in combina-
tion with CO2, as mobile phase, allowed separations by
hydrocarbon groups with flame ionization detector (FID).
CENPES / PETROBRAS purchased its first commercial
supercritical fluid chromatograph in 1995, and since then
it has extended the application of SFC to all hydrocarbon
liquid streams produced in a petroleum refinery.
CENPES has also set up methods to determine oth-
er hydrocarbon groups, like olefins and diolefins in light
and middle hydrocarbon distillates. Although it is gener-
ally assumed that olefins are absent from petroleum, this
compounds are formed during catalytic or thermal crack-
ing of petroleum heavy fractions. These hydrocarbons can
either contribute to increase octane number of gasoline
fuels, or they also play an important role in gum and sol-
ids formation. ASTM has approved another standard test
method (D 6550) to determine total olefins in gasoline fu-
els, also with CO2 as mobile phase and FID detection, but
adding a silver-impregnated column for selective trapping
of unsaturated components, and two 6-port, 2-position
PANEL IV: SCFS AS WORKING FLUIDS / PROCESS TEChNOLOGy AND DESIGN 197
valves, to change flow path of the mobile phase and back-
flush the olefinic components. A different approach was
adopted in CENPES, in which a small, home-made, high-
ly silver-impregnated trap is used. In addition, a different
sequence of timed events for valves actuation during the
analysis was established. These changes make possible to
determine not only olefins, but also saturated and aromatic
hydrocarbons by ring number in a single chromatograph-
ic run. While ASTM D 6550 is restricted to the analysis of
gasoline fuels, CENPES’ method can be applied to the
entire range of atmospheric pressure distilled fractions.
Conjugated diolefins constitute a small fraction of
the total olefins and are strongly related to the instability
of fuels. An analytical method was developed to determine
these substances, again using SFC with conditions simi-
lar to the previous ones, except the detection mode: instead
of FID, UV detection at 240 nm was chosen. Non-aromatic
and aromatic compounds are chromatographically sepa-
rated and conjugated diolefins are the only substances
belonging the non-aromatic peak that absorb UV in this
wavelength. The method is usually applied to petroleum
light distillates (i.e. naphtha fractions), in which most of
the conjugated diolefins concentrate.
Sulfur-containing components can also be grouped
and determined by SFC coupled with sulfur-selective che-
miluminescence detector. Group separation of fossil fuels
by preparative SFC is under investigation to provide green-
er and faster separations, while allowing the isolation of
fractions for further chemical characterization.
CROSS INDUSTRy INTEGRATION FOR POWER PLANTS OF ThE FUTURE AND SUPERCRITICAL FLUIDS
199
CROSS INDUSTRy INTEGRATION FOR POWER PLANTS OF ThE FUTURE AND SUPERCRITICAL FLUIDS
Aydin K. sunolUniversity of South Florida;
Tampa FL 33620, USA;E-mail: [email protected]
Desire for a sustainable world, does should, and will con-
tinue to demand a critical look at the way we meet our
basic needs beyond the ways we are used to even in the
highly capital intensive basic industries which are known
to be very risk averse with demands and incentives for
disruptive changes are incremental and where cross in-
dustry fertilization is only blossoming. This presentation
will provide a forum for discussion of supercritical fluid
cycles, their current utilization and potential impact with
relaxation of cross industry barriers to entry. Specific ex-
amples will include biomass or coal to liquids plant inte-
gration power plants, solar and nuclear power implications,
sequestering implications and integration, and natural
product processing and power integration, and urea/am-
monia production in integrated gasification combined cy-
cle power plants. One of the examples is elaborated in the
abstract.
Coal to liquid conversion, for either liquid fuel or
chemical products, and power go back thousands of years.
Indirect processes that utilize gasification and subsequent
gas to liquids conversion using Fischer Tropsch type syn-
thesis seems be the choice in expense of direct liquefaction
paths that involve hydrogenation of coal using hydrogen
and/or a solvent that itself can donate hydrogen to coal.
200 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
Due to technological and environmental challenges as-
sociated with direct routes, less efficient indirect routes
attracted more interest, in terms of development and com-
mercial effort. A noteworthy exception to the choice is
Shenua plant in Northern China that produces/processes
millions tons/year of coal to liquid fuels using direct routes.
The world’s largest coal to liquids plant employs direct
route at a cost of about $45-$65/barrel.
One interesting direct coal conversion process was
National Coal Board’s (UK) Supercritical Gas Extraction
route using typically Toluene as a solvent. Although per-
cent extracts were lower (around 40-45%), the process
yielded hydrogen rich extract and residue that was as re-
active as the parent coal. The extracts were less condensed
and therefore a lot more amenable to efficient hydrocrack-
ing. The cumbersome solid-liquid separation train was
eliminated while solvent recovery and environmental is-
sues were minimized. The author was first to employ Su-
percritical Water successfully as a solvent for extraction
[1] and similar results were independently reported later
(e.g. Despande et. al. [2]). Water can indeed solubilize hy-
drocarbons at supercritical conditions. We also proposed
to integrate direct and indirect coal liquefaction synergis-
tically benefiting from extract residues that have the re-
activity and energy content of the parent coal.
Power plants that utilize supercritical water have
efficiencies around 45% and have been around for some
time. Thus, the technical know-how for working with su-
percritical water does exist. Power plants that utilize super-
critical water can be a source of solvent for Supercritical
Coal extraction plants. The existent coal feed preparation
and post environmental clean-up facilities are also prem-
ises that make such an integrated technology feasible.
These facilities also include water treatment that benefits
PANEL IV: SCFS AS WORKING FLUIDS / PROCESS TEChNOLOGy AND DESIGN 201
the solvent extraction cause. It is important to point out
that corrosion issues associated with supercritical water
oxidation of waste are not applicable to use of supercriti-
cal water as coal solvent due to non-oxidative nature.
Carbon dioxide capture and sequestering in power
plants as well as coal to liquid plants offer synergistic
integration opportunities as well. For instance, homoge-
nous catalysts that can be used residue gasification, can
be used in capture carbon dioxide. Another possibility is
to co-production urea, a fertilizer.
Features of holistic piloting and modeling programs
that aim to develop integrated conceptual designs of plant
that synergistically combines supercritical cycles of pow-
er plants with chemical production benefit from use of
today’s computational tools such as CFD calculations,
flowsheet simulators and mathematical programming tech-
niques such as Mixed Integer (Non) Linear Programming
as elaborated by Baliban [3]. The economics of the integrat-
ed concept is far more favorable than any of its stand-alone
components. Such power plants not only provide feedstock,
raw material and catalyst, but can utilize the resulting
clean fuels and incorporate sequestering. The proposed
integrated facilities do also share environmental and gas
treatment facilitates. The approaches taken do need to
incorporate life cycle consideration and environmental
impact.
REFERENCES
[1] A. K. Sunol, Supercritical Extraction of Coal, PhD Dissertation, 1982.
[2] G. V. Despande, G.D. Holder, A. A. Bishop, J. Gopal, I. Wender, Ex-
traction of Coal with Supercritical Water, Fuel, 63(7) (1984) 956-960.
[3] R. C. Baliban, J. A. Elia, C. A. Floudas, Optimization framework for the
simultaneous process synthesis, heat and power integration of a ther-
mochemical hybrid biomass, coal, and natural gas facility, Computers
& Chemical Engineering, 35(9) (2011) 1647-1690.
SUPERCRITICAL wATER GASIFICATION AND ITS DEVELOPMENTS IN ChINA
203
SUPERCRITICAL wATER GASIFICATION AND ITS DEVELOPMENTS IN ChINA
Liejin guoState Key Lab of Multiphase Flow in Power Engineering (SKLMF),
Xi’an Jiaotong University (XJTU); Xianning West Road 28# Xi’an, Sha’anxi,710049, The People’s Republic of China;
E-mail: [email protected]
Supercritical water provides an excellent reaction medium
for clean and efficient way in energy conversion. Since
1997, a series of studies on hydrogen production from su-
percritical water gasification have been conducted by the
group of State Key Lab of Multiphase Flow in Power En-
gineering (SKLMF) in Xi’an Jiaotong University (XJTU).
ThEORETICAL RESULTS
Chemical reaction equilibrium analysis is investi-
gated by Gibbs free energy minimization method. The
simulation result confirms the experimental result that as
reaction temperature increases, the hydrogen yield increas-
es. However, as the temperature is above about 600 ºC,
the gas yield is almost constant. That is to say, 600 ºC is
enough and further increase of temperature is not neces-
sary. As for the solar cavity-receiver, the exergy peaks at
about 600 ºC considering the heat loss from the solar
cavity-receiver. So, it sounds a good idea to couple super-
critical water gasification with solar concentrating system.
Separating CO2 is the basic for the CO
2 emission reduction.
High pressure separator is used for separating carbon di-
oxide with other gaseous products. According to phase
equilibrium analysis, the optimal operating condition for
204 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
CO2 capture is obtained. The study on gasification kinetics
model was proposed and it focuses on the main gaseous
products. CFD model is developed for the reactor optimi-
zation and amplification. The above achievement will be
published later. A novel thermodynamics cycle power gen-
eration system is proposed by SKLMP which is based on
coal gasification in supercritical water and multi-staged
steam turbine reheated by hydrogen combustion. It is char-
acterized by its high coal-electricity efficiency, net CO2
emission and no pollutants.
ExPERIMENTAL DEVICE
A quartz tube reaction system with the reactor di-
ameter of 1.5 mm and length of 200 mm was established
to obtain the non-catalytic reaction kinetics. High through-
put autoclaves made of Hastelloy C276 and Inconel 625
were established for the catalyst screening and the reac-
tion mechanism study. A continuous pipe-flow system for
supercritical water gasification was designed for the tem-
perature up to 800 ºC and the pressure up to 30 MPa. A
supercritical water fluidized bed system was developed
to solve the blocking problem and it was designed for the
temperature up to 923 K and the pressure up to 30 MPa.
It is proved from the point of view of thermal dynamics
that supercritical water gasification process driven by con-
centrating solar energy may achieve high efficiency for
hydrogen production. So the first supercritical water gas-
ification device driven by concentrated solar energy was
constructed. Hydrodynamics of a supercritical water flu-
idized bed was conducted and a predicting correlation for
the minimum fluidization velocity in a supercritical water
fluidized bed was obtained based on the experimental
results of a fixed bed and the fluidized bed pressure drop.
PANEL IV: SCFS AS WORKING FLUIDS / PROCESS TEChNOLOGy AND DESIGN 205
ExPERIMENTAL REGULARITy
The feedstock covers various agricultural biomass
(such as corn cob), liquid waste (such as black liquor, phar-
maceutical wastewater), solid wastes (such as municipal
sludge), coal (Yimin lignite, Hongliulin bituminous etc.)
and their model compound. The complete gasification op-
eration condition for each feedstock is obtained. Higher
temperature and oxidative equivalent ratio favors com-
plete gasification. Lignite has highest hydrogen fraction
and yield. Hydrogen gasification efficiency can be as high
as more than two hundred percent. It means that the hy-
drogen we obtained is two times higher than the hydrogen
originally in the coal. The influence of pressure is not sig-
nificant in the experimental scale we investigated; low
concentration favors complete gasification; particles more
than 100 µm needs on more grinding. The co-gasification
characteristics are investigated and Synergistic effect is
found. Organic wastes water can be used as the feedstock
of water-coal slurry. So hydrogen production can be com-
bined with waste treatment. Corrosion is an inevitable
topic for supercritical water gasification. Intergranular cor-
rosion may occur in the reactor inner wall, which can be
restrained by controlling the reaction condition or conduct-
ing corrosion protection treatment such as aluminizing.
CATALyST SCREENING
The catalytic effect of K2CO3 and Raney-Ni was
investigated for gasification in supercritical water. It is
proved that in pipe flow reactor K2CO3 has better catalyt-
ic effect due to the better dispersion. We also conducted
the study of catalyst screening, for the active with high
hydrothermal stability and strong carbon deposition re-
sistance in the process of supercritical water gasification.
Nickel -Magnesium -Al catalyst has been proved to be a
promising catalyst for supercritical water gasification.
206 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
DEMONSTRATION PLANT
Based on the experimental regular and theoretical
result mentioned above, a demonstration plant is estab-
lished in the Ningxia Hui Autonomous Region. The slurry
treatment is more than 1 ton per hour, and the maximal
concentrating power is 163 kW. The demonstration plant
verifies the feasibility of large-scale application of the tech-
nology. The details for the demonstration plant will be
published later. The demonstration plant paves the way
for the industrial application of supercritical water gasifi-
cation and it shows bright future of large-scale application.
ENzyME TREATMENT AND INACTIVATION OF MICROORGANISMS IN COMPRESSED FLUID MEDIA
207
ENzyME TREATMENT AND INACTIVATION OF MICROORGANISMS IN COMPRESSED FLUID MEDIA
José vladimir de oliveiraDepartment of Chemical and Food Engineering,
Federal University of Santa Catarina (UFSC), EQA/CTC; CP 476 – Trindade, 88040-900, Florianópolis, SC, Brazil;
E-mail: [email protected]
This talk comprises a brief review of the state of the art
regarding enzyme treatment in compressed fluids towards
its utilization in enzyme-catalyzed reactions of great in-
terest for chemical and food industries. In particular, great
attention is devoted to oil modification, as well as produc-
tion of GOS and FOS using supercritical carbon dioxide,
propane, n-butane and liquefied petroleum (LPG) gas as
solvent media. Enzyme behavior in compressed fluid me-
dium is discussed in terms of the effects of system pressure
and temperature, exposure time and depressurization rate.
The behavior of free, immobilized and enzyme in solution
are investigated in compressed fluid medium and charac-
terized by several analytical techniques (SEM, XRD, FTIR,
DSC, TGA, etc.). A variety of high-pressure equipment is
shown to be useful for enzyme treatment experiments,
depending on the enzyme form, varying the temperature
from 35 to 75 ºC, in the pressure range of 10-280 bar, expo-
sure times from 1 to 6 hand adopting distinct decompres-
sion rates (compression/expansion cycles). Results showed
that, in general, activity losses are verified for all enzymes
in carbon dioxide, while the use of propane, n-butane and
LPG promoted enhancements of enzyme activity and sta-
bility. In general, within the range studied, temperature
208 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
and exposure times affected positively enzyme activity
while the decompression rates did not demonstrate to be
a relevant variable. Additionally, the use of supercritical
carbon dioxide (scCO2) treatment as an innovative pres-
ervation method to inactivate pathogenic microorganisms
in food products is considered. The effects of scCO2 treat-
ment on the inactivation of Escherichia coli, Listeria mono-
cytogenes and the microbial load of Vibrio parahaemolyticus
in fresh oysters are considered. The effects of exposure
time, scCO2/product mass ratio, temperature, number of
pressure cycles, system pressures from 80 bar up to 200
bar and also pressurization and depressurization rates on
the microbial inactivation is taking into account. A storage
study is also carried out on the treated and untreated prod-
uct to monitor microbial growth. It is shown that treatment
with scCO2 may be a potential technique to reduce micro-
bial growth, which may lead to product’s safety enhance-
ment with possibly increasing shelf life.
REACTOR DESIGN IN SUPERCRITICAL CONTINUOUS FLOW SySTEMS
209
REACTOR DESIGN IN SUPERCRITICAL CONTINUOUS FLOW SySTEMS
Thomas huddleUniversity of Nottingham;
University Park, NG7 2RD, Nottingham, Nottinghamshire, UK; E-mail: [email protected]
This presentation addresses the design of supercritical
continuous flow systems, which can be applied to a large
number of processes, but focuses mainly on their applica-
tion to hydrothermal and solvothermal synthesis of metal
and metal oxide nanoparticles. Continuous flow systems
offer several advantages over traditional batch methods,
and supercritical fluid processing is no exception. On larg-
er scales, continuous flow systems can offer higher through-
put, while minimising the volume of fluid subject to the
often extreme reaction conditions at any one time. A ma-
jor benefit of working with continuous flow systems at an
analytical scale is the ability to rapidly screen a large range
of reaction conditions, which is generally not possible when
working in batch. Several system components are neces-
sitated in supercritical continuous flow designs, but un-
doubtedly the most important feature is the reactor — the
volume in which the desired process occurs. There are
several important considerations related to reactor design
in continuous flow systems, especially with regard to res-
idence time. Residence time (time the flow experiences
reaction conditions) is critical in relation to the activation
energies for a process, and is affected by distribution in
flow paths, stagnant zones, and the rates of heating and
cooling; these are factors which are themselves dependent
210 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
on mixing geometries, turbulence and other effects of the
flow dynamics.
Reactor design is also important when concerning
processes that are liable to form solids, either inherently
(e.g. nanoparticle synthesis), or undesirably (such as char
formation). Small constrictions within reactors or flow sys-
tems may present potential regions for blockage formation,
or allow for accumulation of solids, which may later con-
taminate the product stream. In the case of hydrothermal
metal oxide nanoparticle formation, an ambient tempera-
ture metal salt precursor stream is mixed with a super-
heated water stream. The rapid drop in solubility of the
metal salt at the mixing point allows for a high degree of
supersaturation, which effectively reduces the critical nu-
cleation size, thus driving nanoparticle formation. This
process of mixing the precursor with a preheated stream
may be applied to almost any continuous flow process,
and offers the ability to reach the desired reaction condi-
tions virtually instantly; this can be a very useful technique
for studying kinetics. The process of mixing an ambient
temperature and superheated stream is not straightfor-
ward due to the large differences in density and viscosity.
Traditional mixing geometries such as T-pieces and Y-piec-
es produce poor mixing, with back-mixing and flow strat-
ification often observed. Innovative reactor designs such
as contraflow mixers are able to exploit the differences in
density to achieve highly turbulent mixing, and to minimise
recycling and stagnant zones. A pseudo fluid method is
described as a technique for visualising mixing regimes
within various reactor configurations under different con-
ditions. In this process, ambient temperature water is rep-
resented by aqueous sucrose solution and supercritical
water is represented using methanol. These fluids possess
similar density and viscosity ratios to those between am-
PANEL IV: SCFS AS WORKING FLUIDS / PROCESS TEChNOLOGy AND DESIGN 211
bient temperature water and supercritical water. By ad-
justment of the flow rates and pseudo reactor dimensions,
similar Reynolds and Grashoff numbers can be achieved
to those experienced in reactors under supercritical con-
ditions. This technique allows quantification of mixing
efficiency, as well as visualisation of issues such as flow
recycling, stagnant zones, and other inconsistencies in
the mixing dynamics. For a more genuine representation
of flow path distributions within supercritical continuous
flow systems, a technique involving injection and UV de-
tection of chromophoric tracers is discussed. Using this
method, residence time distributions can be compared
between reactors, and the effect of stagnant zones at var-
ious points of the continuous flow system may be assessed.
Such data provides useful experimental validation of CFD
simulations for reactors. Other reactor geometries will also
be assessed using these techniques, such as those involv-
ing concurrent mixing and others which feature multiple
precursor stream inlets; the pros and cons of each will be
discussed and contrasted to contraflow mixing.
ACOUSTIC wAVE GENERATION IN NEAR-CRITICAL SUPERCRITICAL FLUIDS: EFFECTS ON MASS TRANSFER AND ExTRACTION
213
ACOUSTIC wAVE GENERATION IN NEAR-CRITICAL SUPERCRITICAL FLUIDS: EFFECTS ON MASS TRANSFER AND ExTRACTION
Bakhtier farouk, nusair hasanDepartment of Mechanical Engineering and Mechanics,
Drexel University; Philadelphia, PA 19104, USA
Supercritical fluid extraction (SFE) is a technique that adds
a supercritical fluid of an extraction medium to a sample
containing a constituent targeted for extraction. Extraction
by means of supercritical fluid can be expected to improve
efficiency, including shorter extraction times and simpli-
fied procedures when compared with extraction techniques
that employ organic solvents. Use of supercritical carbon
dioxide has received recent attention as an environmen-
tally friendly extraction technique that does not use haz-
ardous organic solvents, as has been advocated by the
green chemistry movement in recent years. The conven-
tional process of extracting solutes from a solid matrix
(packed bed) using supercritical solvents has a very slow
dynamics even when solute free solvent is re-circulated
and therefore improvements in the extraction process are
required. The use of acoustic waves represents a potential
effective method of enhancing mass transfer (extraction
and separation) processes with supercritical fluids. Recent
results of mass transfer enhancement by using resonant
acoustic waves will be presented. Acoustically augment-
ed flow and transport in supercritical carbon dioxide gen-
erated by standing wave in a cylindrical enclosure was
simulated. The oscillatory flow field in the enclosure is
created by the vibration of one of the end walls of the
214 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
enclosure. The geometric parameters and the frequency
of the vibrating wall are chosen such that the lowest
acoustic mode propagates along the enclosure. A real-fluid
model for representing the thermo-physical and transport
properties of the supercritical fluid is considered. The ful-
ly compressible form of the Navier-Stokes equations is
used to model the flow fields and an implicit time-march-
ing scheme is used to solve the equations. The formation
of the acoustic field in the enclosure is computed and ful-
ly described and the acoustic boundary layer development
is predicted. The interaction of the wave field with viscous
effects and the formation of streaming structures are re-
vealed by time-averaging the solutions over a given period.
Due to diverging thermo-physical properties of supercrit-
ical fluid near the critical point, large scale oscillations
are generated even for small sound field intensity. The
effects of near-critical property variations and system pres-
sure on the formation process of the streaming structures
are also investigated. Application of the acoustically aug-
mented flow in extraction of caffeine from coffee beans
using supercritical carbon dioxide is demonstrated numer-
ically. The predicted results confirm that acoustic waves
significantly accelerate the kinetics of the supercritical
extraction process, especially in the near-critical region
of operation and improve the final extraction yield.
PANEL PRESENTATIONS
Panel V: Process Technology and Future Direction
DEVELOPING AN INTEGRATED SUPERCRITICAL FLUID BIOREFINERy FOR ThE PROCESSING OF GRAINS
217
DEVELOPING AN INTEGRATED SUPERCRITICAL FLUID BIOREFINERy FOR ThE PROCESSING OF GRAINS
feral Temelli, ozan nazim ciftciDepartment of Agricultral, Food and Nutiritonal Science,
University of Alberta; 4-10 Agr/For Centre, T6G2P5, Edmonton, Alberta, Canada;
E-mail: [email protected], [email protected]
Limited supply of petroleum resources together with the
ever increasing demand for petroleum-based products has
fueled the emergence of the bioeconomy. Global trends
highlight the growth in fuel, energy, materials, chemicals
and other products based on renewable feedstocks as eco-
nomically viable alternatives to petroleum-based products.
This has led to the “biorefinery” concept of processing
renewable feedstocks similar to that in a conventional oil
refinery and petro-chemical complex, where crude oil is
separated into various fractions and with further processing
converted into a vast array of products. Thus, a biorefinery
would integrate a variety of separation and conversion
processes to produce multiple product streams from renew-
able feedstocks. Industrial-scale integrated biorefineries
are critical for the growth of a sustainable bioeconomy.
Grains of cereals and oilseeds are a promising source of
renewable feedstock for biorefineries. Grains are composed
of lipids, proteins, carbohydrates as well as moisture, ash
and other minor components. Most of the conventional
processes result in underutilization of the grains by focus-
ing on only one or a limited number of components of the
grains; therefore, the full value of grains is underestimat-
ed. In an integrated biorefinery, the first major stage would
218 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
focus on the separation processes to fractionate the major
and minor components of the grains. Then, in the second
stage, these fractions would be converted to other high
value ingredients/intermediates/products through various
conversion processes. Finally, application development is
critical for these ingredients/intermediates to be utilized
in a variety of end uses, depending on their functionality,
targeting food, nutraceutical, pharmaceutical, cosmetic,
biofuel, biochemical, biomaterial and other industries. In
addition to some of the conventional separation and con-
version technologies, supercritical fluid technology has a
major role to play in developing such an integrated biore-
finery, considering the well-known advantages of supercrit-
ical carbon dioxide (scCO2). Among the major components
of lipids, proteins and carbohydrates, scCO2 can selective-
ly extract lipids, more specifically neutral lipids and lipid-
soluble minor components, such as tocopherols, carotenoids
and phytosterols. The residual proteins and carbohydrates
would be of high quality and functionality as opposed to
the case when petroleum-based solvents are used for lip-
id extraction. For example, canola proteins had better qual-
ity when lipids were extracted with scCO2 compared to
those obtained after hexane extraction. The residual pro-
tein/carbohydrate mixture can be further fractionated us-
ing alkali extraction and/or subcritical water extraction
technology. The crude lipids extracted by scCO2 can be
fractionated to isolate the high-value minor lipid compo-
nents. The neutral lipids, specifically triglycerides, can be
used as is or can be converted to other valuable compo-
nents through enzymatic or non-enzymatic reactions in
scCO2 media. For example, triglycerides solubilized in scCO
2
can be converted to biodiesel through lipase-catalyzed
transesterification with methanol or ethanol to form fatty
acid methyl or ethyl esters, respectively. Minor lipid com-
PANEL V: PROCESS TEChNOLOGy AND FUTURE DIRECTION 219
ponents can be encapsulated via various particle forma-
tion techniques, where the protein or carbohydrate fractions
can be used as the coating material to form novel delivery
systems for these bioactive components. All of the above
scCO2-based unit operations have been demonstrated for
various grains of cereals and oilseeds, rich in lipids. Over
the past three decades, the know-how has progressed sub-
stantially towards integration of these unit operations to
develop a biorefinery. However, there are challenges in
terms of the large scale equipment and operations expect-
ed of biorefineries to be able to compete with the petro-
leum-based refineries. Therefore, it is critical to integrate
the recovery of low-volume but high-value ingredients for
favorable process economics. As well, defining the optimal
scale of operation is essential to achieve economies of scale.
Construction of continuous scCO2 extraction units to re-
place the commonly used semi-continuous systems in
operation today is essential to handle the large volumes
of grains as feedstock. Feedstock diversity, including lo-
cation and year-to-year variability, is another challenge
for process optimization. This can be overcome by strate-
gic location of biorefineries, targeting optimization of op-
erations for the grain specific to that region. Environment
friendly aspect of scCO2-based biorefineries may ease the
protocols of acquiring regulatory permits. Building part-
nerships with conventional industries that produce large
quantities of CO2 can be a win-win situation to reduce
greenhouse gas emissions. On the other hand, consumer
education on the advantages of scCO2 technology is im-
portant to grow the demand for products of such a green
technology, which in turn will force the industry to adopt
supercritical fluid technology to a greater extent. The po-
tential for employing scCO2 technology in an integrated
biorefinery is just starting to be realized and offers prom-
220 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
ise for cost-effective and environmentally friendly process-
ing of the grains to produce ingredients/products for food,
nutraceutical, pharmaceutical, cosmetic, fuel, chemical
and materials applications. Complete utilization of all the
grain components in such a biorefinery will also reduce
the food vs. fuel competition. It will also help meet the
growing consumer demand for “natural” products pro-
cessed with green technologies. scCO2-based biorefineries
may play a key role in moving towards a sustainable bio-
economy via process intensification, by reducing energy
requirements and waste streams, and increasing process
efficiency while providing a range of food and non-food
ingredients/products.
PROCESSING OF OLIGOMERIC SySTEMS VIA SCE FOR ENERGy AND MATERIALS APPLICATIONS
221
PROCESSING OF OLIGOMERIC SySTEMS VIA SCE FOR ENERGy AND MATERIALS APPLICATIONS
David f. Esguerra, Julian velez, Adam scott, Mark c. Thies
Dept. of Chemical and Biomolecular Engineering, Clemson University;
29634-0909, Clemson, SC, USA; E-mail: [email protected]
CARBONACEOUS PITChES AND OLIGOMERS
Carbonaceous oligomeric pitches can be used as
precursors for a variety of high-performance carbon ma-
terials for energy and materials applications, including
cathodes for lithium ion batteries, high thermal conduc-
tivity carbon fibers, and carbon-based composites. These
oligomeric materials can be produced from a variety of
resources, including coal tar, petroleum by-products, and
pure polycyclic aromatic hydrocarbons (PAHs), using ei-
ther thermal or catalytic polymerization processes.
A long-term goal of our group is to understand how
the oligomeric composition of carbonaceous pitches af-
fects their bulk properties. In previous work with pitches
derived via thermal polymerization from the petroleum
by-product decant oil, Thies and co-workers showed how
supercritical extraction (SCE; also called dense-gas ex-
traction, or DGE) could be used to isolate these petroleum
pitches into their respective oligomers. The oligomeric frac-
tions were then available for analysis using both conven-
tional and advanced characterization techniques. Examples
of information obtained therefrom included definitive mo-
lecular structures for the dimers of petroleum pitch, soft-
222 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
ening points of dimer cuts, and the discovery of liquid
crystallinity in trimer cuts.
The goal of this study is to fractionate via SCE a
carbonaceous pitch produced via the catalytic polymer-
ization of the PAH monomer pyrene into its constituent
oligomers. Isolating the oligomers of pyrene pitch would,
for the first time, provide information about the oligomer-
ic content of a pitch produced catalytically from pure PAHs.
The use of both neat toluene (Tc = 318.6 °C; Pc = 41.1
bar) as the SC solvent, and the addition of N-methyl-2-
pyrrolidone (NMP; Tc = 450.94 °C; Pc = 47.2 bar) as a
co-solvent, is being explored.
Previous work on the fractionation of carbonaceous
pitches (typically carried out prior to an analytical char-
acterization step) has been limited primarily to (a) solvent
extraction methods, such as sequential Soxhlet extraction
with the solvents benzene, pyridine, and quinoline, and
(b) the simple separation of the pitch into solvent-soluble
and insoluble fractions. However, as has been shown by
Edwards and Thies, conventional solvent extraction meth-
ods produce fractions that are still quite broad in their
molecular weight distribution (MWD). Thus, in the above-
mentioned previous work, no information about the pre-
ponderance of the various oligomers in the original pitch
was reported, and the focus was on presenting average
properties for pitch fractions isolated, versus definitive
molecular structures.
LIGNIN FROM BIOMASS By-PRODUCT STREAMS
Another poorly defined oligomeric system for which
supercritical fluid processing can provide unique advan-
tages is the biopolymer lignin. Lignin is one of the most
common organic compounds on earth, comprising about
30% of all organic carbon. Only cellulose is more abundant.
PANEL V: PROCESS TEChNOLOGy AND FUTURE DIRECTION 223
In a pulp and paper mill, the pulping process is used to
dissolve away the lignin fractions of wood, liberating the
cellulosic fibers from the wood matrix in the form of a pulp
that is then used to make paper. This chemical digestion
of the lignocellulosics in wood is accomplished through
various pulping processes (with the kraft sulfate process
being globally dominant), and the lignin ends up in a
by-product stream known as “black liquor”. Typically, this
black-liquor stream is burned in the recovery furnace of
the paper mill for its fuel value and to recover the inorganic
ash that is returned to the pulping process.
If the high-ash (~50 wt%) lignin in this black liquor
could be isolated in a dry, low-ash (0.5-2.0 wt%) state, the
result would be an excellent-quality, low-cost biofuel with
essentially the same energy content as coal and about
50% more energy than low-moisture wood pellets. Taken
yet another step, if the lignin could be recovered in the
“ultrapure” state, in particular with a low metals content
and a controllable molecular weight, it would be much
more than a fuel — it would be a high-value, renewable
biopolymer. Such an ultrapure lignin would have a wide
range of uses because lignin is unique among abundant
biopolymers in having aromaticity. For example, research-
ers have suggested that an ultrapure lignin could be used
as the oligomeric feedstock for manufacturing low-cost
carbon fibers, which could then be used for automotive
structural applications. The result would be dramatic re-
ductions in the weight of the U.S. vehicle fleet — and con-
current increases in fuel mileage.
In summary, lignin separated from Kraft black li-
quor has the potential to become an inexpensive and re-
newable platform for the production of aromatic chemicals,
bio-based materials, and clean biofuels. However, the het-
erogeneity of lignin presents a challenge for obtaining a
224 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
more fundamental understanding of the chemical struc-
ture of this material. This is where supercritical fluids can
play a role. The fractionation of lignin via SCE processing
has two potential benefits: (1) chemical structure-vs.-bulk
property relationships can be obtained, and (2) the frac-
tions themselves can have properties useful for various
applications.
SUPERCRITICAL TEChNOLOGy APPLIED TO FOOD PROCESSING
225
SUPERCRITICAL TEChNOLOGy APPLIED TO FOOD PROCESSING
Julian MartínezLASEFI/DEA/FEA (School of Food Engineering),
UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil;
E-mail: [email protected]
Some solvents at high pressures are used as alternatives
to liquid organic compounds in industrial processes, due to
their lower toxicity, adequation to environmental exigen-
cies, easy separation, and possibility of using moderate
temperatures. In the food industry, carbon dioxide (CO2)
is the most applied solvent, due to its non-toxicity. At high
pressures, generally at the supercritical state, CO2 has
been used as extraction solvent for coffee decaffeination,
production of hop extracts and volatile oils used as con-
diments. In the research field, many groups have been
working with supercritical CO2 extraction from novel sourc-
es, to obtain condiments, aromas and compounds with
high nutritional or medicinal value. In food engineering
the raw materials for extraction may be native plants or
even wastes from the food industry, which often contain
valuable compounds.
As well as SFE, extraction with pressurized liquids
(PLE) appeared as an alternative to extraction and frac-
tionation of natural products, since it is a clean technolo-
gy that allows controlling process parameters to tune the
selectivity for a specific group of compounds, which is a
feasible way to aggregate value to natural extracts. Water
as a PLE solvent is non-toxic, non-flammable, cheap and
environmentally safe. Indeed, PLE allows fast extraction
226 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
in closed and inert systems at high pressure and moderate
temperatures. Another advantage of PLE is that, at high
pressures, solvents remain liquid at temperatures above
their boiling point, where the solubility of some compounds
may be enhanced. Of course, in this case the target com-
pounds cannot be sensible to high temperatures. There-
fore, PLE using water as solvent may be complementary
to SFE with CO2, since the polar nature of water allows
extracting compounds that would be insoluble in CO2. In
this sense, one can use both techniques as sequential
steps of a unique process, to obtain products with different
properties from the same raw material.
Ultrasound is used to increase the efficiency of ex-
traction, since it reduces the required temperature and
favors the dissolution of target compounds in the chosen
solvent. Ultrasonic waves cause expansion and compres-
sion of bubbles in the solvent, which may collapse and
lead to cavitation. Near natural raw materials, cavitation
can result in rupture of cell walls, allowing the penetration
of the solvent inside the cells, and thus enhancing mass
transfer. In SFE, ultrasound can promote desorption of
extractable material from the sold surfaces. Therefore, the
application of ultrasound during extraction with liquid or
supercritical solvents can increase the yield and velocity
of the process.
Bioactive compounds can be highly sensible to heat,
light, oxygen or other adverse conditions. Moreover, the
functionality of such compounds may be favored when
they are gradually liberated into the organism. This is,
mainly, the case of pharmaceutics, but it can also be ap-
plied to food ingredients. In this context, mechanisms to
protect the compounds from adverse conditions and make
possible their controlled liberation are needed. Encapsu-
lation, through formation of micro or nanoparticles with
polymeric matrices, is a known strategy to obtain such
PANEL V: PROCESS TEChNOLOGy AND FUTURE DIRECTION 227
results. Methods for particle formation using supercritical
fluids have been explored as alternatives to consolidated
techniques, such as spray-drying, fluidization or freeze-dry-
ing, and their results are promising. Among these tech-
niques, some use the supercritical fluids as antisolvent,
i.e., the supercritical fluid is used to remove a liquid solvent
from a mixture, leading to the precipitation of particles
inside the polymer. Two techniques can be highlighted in
this context: Supercritical Antisolvent (SAS) Precipitation
and Supercritical Fluid Extraction of Emulsions (SFEE).
The advantages of supercritical technology for particle
formation are the reduced need of handling materials that
allows enhancing yield, easy equipment cleaning, and
therefore, increased viability for scale-up, besides the pos-
sibility of operating in continuous mode.
In the SAS process a liquid solution containing the
target compound or product is brought to contact with a
supercritical fluid. As a result, the liquid is saturated with
the supercritical fluid, leading to the precipitation of the
product. A polymer can act as encapsulation agent in this
process, resulting in the formation of particles of the prod-
uct involved or spread in the polymer. This technique has
been studied for the precipitation of pharmaceuticals and
bioactive compounds present in food, such as carotenoids.
The main disadvantage of the SAS process, as well
as of other precipitation techniques using supercritical
fluids, is the control of particle size. It is difficult to obtain
particles below micrometric scale, and particle agglom-
eration in frequent. The SFEE process may solve these
problems, because in this case the precipitation occurs
from droplets of an emulsion, where the target product is
in the disperse phase. The supercritical fluid extracts the
solvent from this phase, leading to the precipitation of the
target compound with the polymer, and the particles re-
main suspended on the aqueous phase. Thus, the particle
228 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
size can be monitored through the size of the emulsion
droplets. Due to the nature of the process, SFEE is recom-
mended to produce particles of compounds not soluble or
poorly soluble in water, such as carotenoids, oils, and oth-
er compounds with application in food.
Finally, supercritical fluids can be reaction means
in the synthesis of various products, as biofuels, and in
the food industry, terpenic esters with flavor properties
and sugar esters that can be applied as emulsifiers in pro-
cessed food formulations. In these processes, immobilized
enzymes catalyze reactions in supercritical CO2. Theoret-
ical and practical works indicate that lipases are efficient
in such processes, and can be used in various reaction cy-
cles. As well as in SFE, the separation of the reaction prod-
ucts and the solvent can be achieved by pressure reduction.
Therefore, supercritical fluids can replace toxic organic
solvents that are typically employed as reaction means in
the industry.
Our research group has been concentrating its works
on the mentioned techniques, with emphasis in products
from natural sources with applicability in food pro cessing
and products. As examples, researches are being con-
ducted on the following processes: SFE from red pepper,
assisted or not by ultrasound, to obtain extracts with cap-
saicin, and further encapsulation of the extracts with SAS
or SFEE; recovery of anthocyanins and other phenolics
from blueberry and blackberry wastes, for subsequent par-
ticle formation by SAS; extraction and encapsulation of
bioactive compounds from passion fruit residues; and en-
zymatic synthesis of terpenic esters on supercritical CO2
to produce food flavors. Nine master and PhD students are
involved in such works, and the process units are devel-
oped in our laboratory. The possibility of coupling different
processes with supercritical fluids, or even to other clean
technologies should be studied in future works of our group.
ANALySIS OF SAVING OF ORGANIC SOLVENTS IN ThE RECOVERy OF ANTIOxIDANTS FROM VEGETAL SOURCES By SFE
229
ANALySIS OF SAVING OF ORGANIC SOLVENTS IN ThE RECOVERy OF ANTIOxIDANTS FROM VEGETAL SOURCES By SFE
Tiziana fornariInstituto de Investigación en Ciencias de la Alimentación,
CIAL (CSIC-UAM); C/Nicolás Cabrera 9, Campus de Cantoblanco, 28049 Madrid, Spain;
E-mail: [email protected]
The processing of vegetal materials to recover phytochem-
icals with biological activity is currently an interesting
matter of new markets. Supercritical fluid extraction (SFE)
with carbon dioxide (CO2) is a competitive technology in
this field, being one of the “Top Ten List” of CO2-SFE ben-
efits the advantage of recovering the extract with high
purity, completely free of solvent. Since no organic solvents
are employed, subsequent processing for its elimination
and recycling is not required. However, it is well known
that the consumption of organic solvents in SFE not al-
ways can be circumvented. In fact, the supercritical CO2
extraction of polar or even moderate polar compounds gen-
erally requires the use of an adequate cosolvent to enhance
yield and to design processes with acceptable economic
profit. Hundreds of examples can be given in which the
addition of a small amount of cosolvent (ethanol, aceto-
nitrile, ethyl acetate, among others) produce considerably
increases of extraction yield and recovery of target com-
pounds. Among these target compounds a number of po-
lar antioxidants, such as flavonoids and phenolic acids,
require the use of cosolvents to attain their SFE from veg-
etal matter [1]. But even in the case of moderate polar
antioxidants the use of small amounts of an acyl alcohol
230 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
as cosolvent of CO2 considerably increase the extraction
yield. In these cases, the most frequently proposed cosol-
vent is ethanol since its traces in the final product is
permitted in food, nutraceutical or pharmaceutical appli-
cations. For example, it is well known that the solubility
of several phenolics, including gallic acid, catechins, res-
veratrol, quercetin and salicylic acid, in CO2 containing
small amounts of methanol or ethanol is considerable
higher in comparison with their solubility in pure CO2 [2].
Thus, a remarkable increase in the recovery of these sub-
stances is observed if alcohol cosolvents are included in
the supercritical CO2 extraction process [3]. Another ex-
ample is the recovery of carnosic acid, a moderate polar
lipophilic phenolic diterpene present in rosemary leaves.
It has been reported that the addition of 5-10% ethanol as
CO2 cosolvent can duplicate extraction yield, producing a
4-7 fold increase of this antioxidant in the extract, while
a minor effect on the recovery of essential oil constituents
was observed [4]. Despite the benefits that the use of a
cosolvent can produce in particular applications, when
a cosolvent is employed the most outstanding advantage
of SFE in comparison with solvent-based technologies
seems to be somewhat lost. Thus, other extraction alter-
natives such as ultrasound assisted extraction (UAE) or
pressurized liquid extraction (PLE) appear as competitive,
because both are much more effective regarding organic
solvent consumption in comparison with traditional solid-
liquid extraction (SLE). The point is to assess the efficien-
cy in terms of solvent consumption vs. recovery of target
phytochemicals, which can be a decisive matter of analy-
sis when selecting the extraction technology to be applied
in a particular case. As a case of illustration, it can be
mentioned the extraction of carnosic acid from the same
lot of rosemary leaves (45 mg carnosic acid per g of dry
PANEL V: PROCESS TEChNOLOGy AND FUTURE DIRECTION 231
matter) using different techniques. Quite different results
are obtained if the amount of antioxidant extracted was
referred to the amount of liquid solvent employed. All SLE,
UAE, PLE and SFE produced good recovery of carnosic
acid (higher than 60%) under appropriate extraction con-
ditions. Nevertheless, the consumption of ethanol is very
different, when considering the mg of carnosic acid ex-
tracted per mL of ethanol consumed. UAE and PLE require
one-fifth of the solvent employed in SLE to produce even
somewhat higher recoveries. But, in comparison with the
supercritical extraction (assisted or not with ultrasound)
the increase of carnosic acid recovery per mL of ethanol
employed is noteworthy (7-10 times higher). A comparison
of the efficiency of using organic solvents in the recovery
of antioxidants from several different plant matrixes and
using different technologies will be presented and dis-
cussed. Antioxidants such as phenolic diterpenes, triterp-
enic acids and carotenoids will be considered, and examples
of SLE, UAE, PLE, and SFE with pure CO2 and assisted
with ethanol cosolvent will be pondered.
ACKNOWLEDGEMENTS
This work was financed by project ALIBIRD, S2009/AGR-1469 (Comunidad
de Madrid, Spain).
REFERENCES
[1] E. Reverchon, I. De Marco, Supercritical fluid extraction and fraction-
ation of natural matter, J. Supercritical Fluids, 38 (2006) 146-166.
[2] R. B. Gupta, J-J Shim, Solubility in supercritical carbon dioxide, CRC
Press, Taylor and Francis Group (2007).
[3] M. T. Tena, A. Ríos, M. Valcárcel, Supercritical fluid extraction of
t-resveratrol and other phenolics from a spiked solid Fresenius, J.
Analytical Chemistry, 361 (1998) 143-148.
[4] T. Fornari, G. Vicente, E. Vázquez, M. R. García-Risco, G. Reglero, Iso-
lation of essential oil from different plants and herbs by supercritical
fluid extraction, J. Chromatography A, 1250 (2012) 34-48.
ThE PRODUCTION OF FERMENTABLE SUGARS By ThE SUBCRITICAL WATER hyDROLySIS OF FOOD INDUSTRy RESIDUES
233
ThE PRODUCTION OF FERMENTABLE SUGARS By ThE SUBCRITICAL WATER hyDROLySIS OF FOOD INDUSTRy RESIDUES
Juliana M. pradoCTBE (Brazilian Bioethanol Science and Technology Laboratory) /
CNPEM (Integrate Brazilian Center of Research in Energy and Materials); R. Giuseppe Máximo Scolfaro, 10.000, 13083-970, Campinas, SP, Brazil
Tania forster-carneiro, M. Angela A. MeirelesLASEFI/DEA/FEA (School of Food Engineering),
UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil;
E-mail: [email protected]
Bioethanol has been investigated as a potential alterna-
tive to liquid fossil fuels due to its eco-friendly character-
istics and relatively low production cost. First-generation
bioethanol is produced today from raw materials that are
rich in simple sugars or starch, such as sugarcane and
corn. However, these crops are also food sources for both
humans and animals. To avoid the fuel versus food dilem-
ma, second-generation bioethanol aims to use non-edible
raw materials as the source of fermentable sugars. Ligno-
cellulosic residues from the food industry fulfill these re-
quirements because they are not used as food sources and
do not occupy farmable lands. The hemicellulosic and cel-
lulosic fractions of the biomass can be hydrolyzed into
fermentable sugars by several methods, using acid, alkali
or enzymatic catalysts. With increasing knowledge of the
processes that take place during the hydrolysis of biomass
come new techniques, which are being exploited to im-
prove the process. Sub/supercritical water hydrolysis (SWH)
has been demonstrated to have significant potential for
use as a highly efficient hydrolytic process with several
234 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
advantages over conventional processes, such as the lack
of need for pre-treatment, shorter reaction times, lower
corrosivity, lower residue generation, the lack of use of
toxic solvents and the reduced formation of degradation
products. However, further optimization of the operating
conditions (temperature, time, solvent:solid proportion) and
economic evaluations of the process are still needed so
that the technique can be scaled-up to the industrial level.
A semi-batch unit equipped with a 50-mL reaction vessel
that can operate up to 400 °C and 400 bar, with the possi-
ble addition of CO2 as an acid catalyst, was built. The unit
was used to perform the subcritical water hydrolysis of
sugarcane bagasse, pressed palm fiber, coconut husk and
defatted grape seeds at water flow rates of 10-55 mL/min,
temperatures of 200-300 °C, total processing times of 30-60
min and under 20 MPa of pressure. The results obtained
using pure water as the reaction medium were compared
with the results obtained using water + CO2 as the reac-
tion medium. Fractions of the hydrolysate were collected
every 2 min. The hydrolysates were analyzed for pH, total
reducing sugars, monosaccharides and degradation prod-
ucts. The maximum total reducing sugars recovered for
sugarcane bagasse was 23% at 214 °C and 55 mL/min
using pure water as the reaction medium. For pressed palm
fiber, coconut husk and defatted grape seeds, the maxi-
mum values of total reducing sugars obtained were 11.5%
(256 °C, with pure water), 14% (262 °C, with CO2), and 10%
(258 °C, with CO2), respectively. The total reducing sugars
recovered increased with temperature; however, for the
coconut husk and defatted grape seeds, the value only
increased with the addition of CO2. The total degradation
products increased with temperature, while the monosac-
charides remained approximately constant, which means
that more oligosaccharides were recovered at higher tem-
PANEL V: PROCESS TEChNOLOGy AND FUTURE DIRECTION 235
peratures, due to the increased efficiency in the break-
down of cellulose. Each raw material presented different
behaviors when subjected to the same operational condi-
tions. Therefore, each lignocellulosic biomass should be
individually studied for SWH. Nevertheless, SWH appears
to be a promising technology for the recovery of fermentable
sugars from lignocellulosic residues in the food industry.
ACKNOWLEDGEMENTS
J. M. Prado thanks FAPESP (2010/08684-8) for the postdoctoral fellowship.
The authors acknowledge funding from FAPESP and CNPq.
ThE INTEGRAL UTILIzATION OF BIOMASSES BASED ON SUB/SUPERCRITICAL FLUIDS: ENVIRONMENTAL, ENERGETIC AND ECONOMIC ASSESSMENTS OF TEChNOLOGICAL SCENARIOS
237
THE INTEGRAL UTILIZATION OF BIOMASSES BASED ON SUB/SUPERCRITICAL FLUIDS: ENVIRONMENTAL, ENERGETIC AND ECONOMIC ASSESSMENTS OF TECHNOLOGICAL SCENARIOS
Juliana Q. Albarelli, Adriano V. Ensinas, François Maréchal Industrial Energy Systems Laboratory (LENI),
Swiss Federal Institute of Technology Lausanne (EPFL); Station 9, CH-1015, Lausanne, Switzerland;
E-mail: [email protected]
M. Angela A. MeirelesLASEFI/DEA/FEA (School of Food Engineering),
UNICAMP (University of Campinas);R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil
Second generation ethanol production has been an im-
portant line of research around the world. In the Brazilian
scenario, sugarcane bagasse is the main material inves-
tigated for the production of cellulosic ethanol. The con-
cept of integrating its production with the conventional
technique of ethanol production from sugarcane in a biore-
finery has been studied by different researchers. Experts
agree that future biorefineries should focus on the produc-
tion of high value products prior to biofuel and/or energy
production. In view of this and considering the remaining
obstacles for the establishment of a sugarcane biorefinery,
the sub/supercritical technology stands out. Because such
technology demands substantial energy consumption,
strat egies for energy consumption reduction must be de-
veloped in addition to process optimization. Currently, our
research group is contributing to this scientific and techno-
logic demand, comparing the sub/supercritical technology
with other potential technologies at a su garcane biorefin-
ery using simulation tools. Simulation tools play an impor-
238 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
tant role as decision-support tools that assist in designing
the infrastructure for cellulosic ethanol production and
sugarcane biorefineries. In this sense, the software ASPEN
PLUS and VALI have been used to evaluate the main pro-
cesses, including the supercritical extraction, supercritical
hydrolysis and supercritical gasification of sugarcane ba-
gasse. All of the processes analyzed are thermally integrat-
ed with the sugarcane biorefinery using Pinch Analysis.
The processes are analyzed in light of their economic and
environmental impacts, and multi-objective optimization
is performed using the software OSMOSE, developed by
LENISYSTEM/LENI/EPFL (Switzerland). In the near future,
this project will also evaluate different technology scenar-
ios developed mainly in LASEFI/DEA/FEA/UNICAMP that
aim to integrate the use of different biomasses using sub/
supercritical fluids at all stages. In this regard, future biore-
fineries based on the sequential acquisition of secondary
metabolites using supercritical ethanol and CO2, in addi-
tion to the subsequent fractionation of biomass using sub-
critical water and the production of monosaccharides from
cellulose-rich solid waste using supercritical water, will
be evaluated. Finally, the integration of the sugarcane and/
or microalgae biorefinery will be evaluated for the biore-
fineries studied, with the goal of obtaining energy efficien-
cy and the economic and environmental impacts, as well
as performing multi-objective optimization.
POLyMER FOAMING WITh SUPERCRITICAL CO2 — ChALLENGES IN BATCh-WISE AND CONTINUOUSLy OPERATED PROCESSES
239
POLyMER FOAMING WITh SUPERCRITICAL CO2 — ChALLENGES IN BATCh-WISE AND CONTINUOUSLy OPERATED PROCESSES
sulamith frerich, Marcus petermannRuhr-University Bochum;
Universtitaetsstr. 150, IB 6/140, 44801, Bochum, NRW, Germany; E-mail: [email protected]
Polymers are versatile materials. They can be used in var-
ious shapes and colours, and their properties vary in a
broad range. Once polymers are processed into foams, they
show a high stability combined with low weight, due to
the encapsulated gas.
Usually, a foaming procedure consists of several
steps. First, the fluidised polymer is mixed with a blowing
agent. Second, the blowing agent causes the foam struc-
ture via nucleation and growth of gas bubbles into the
polymer matrix. Finally, the foam needs to be stabilised.
The foam morphology is distinguished between open cells
and closed cells, depending on the pore structure. A com-
bination of both types is possible, too, so-called integrat-
ed-foams with dense shells and porous cores. These foams
show a very high rigidity, and the shell prevents water and
dirt penetrating the foam [1].
Several substances have already been investigated
as blowing agents, such as water vapour and low boiling
organic liquids [2]. However, disadvantages like conden-
sation during cooling (vapour) and residues in the foams
(organic liquids) made their industrial application difficult,
especially in the food industry. Therefore, alternative sub-
stances were investigated as blowing agents [3]. Super-
critical fluids like nitrogen or carbon dioxide are promising
240 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
substances. They show a high density at elevated tem-
peratures and pressures and dissolve into the polymer.
Hence, residue-free foams with fine pores can be created
by depressurising a polymer-gas-system. Since the solu-
bility of carbon dioxide in polymers is usually higher than
nitrogen, its ability as blowing agent has been investi-
gated.
The application of polymer foams in thermal insu-
lation requires very small pores, a low interconnectivity,
and a robust polymer matrix. Nucleation and growth are
competitive in creating the pore structure, and the final
stabilisation has a great influence on the foam properties.
It is therefore important to investigate the quasi-binary
system polymer-carbon dioxide during the whole proce-
dure and determine its behaviour and properties under
different parameters.
In general, the melt behaviour and rheology of the
polymer-carbon dioxide mixture under high pressure and
temperature influences its handling. Due to the dissolution
of carbon dioxide into the polymer matrix, the melting
temperature of the polymer decreases. This so-called gas
induced melting point reduction enables economisation
by saving heating energy. The gas-enriched polymer melt
usually shows a lower viscosity, too. It is therefore easier
to process the polymer through a plant. However, solubil-
ity and diffusion coefficients have to be determined, since
they are influencing the amount of gas dissolved into the
polymer, and therefore, the quality of porous structures
created. The concentration of carbon dioxide in the poly-
mer phase is crucial in the foaming procedure, as a certain
amount of dissolved gas is needed to expand the polymer
sufficiently. The mixing behaviour of polymers and carbon
dioxide is also important, since a good miscibility enables
foams with a more homogeneous pore size distribution.
PANEL V: PROCESS TEChNOLOGy AND FUTURE DIRECTION 241
Once the polymer-gas-system is depressurised, short
chain length components such as additives or residue mono-
mers might be extracted. Thus, the properties of the remain-
ing porous polymer matrix differ from them of the original
polymer. The separation of the gas phase from the polymer
foam is the most crucial step in processing. For producing
polymer foams in large dimensions and quantities, con-
tinuous processes are preferable to batch-wise procedures.
However, high pressure conditions in continuously oper-
ated procedures are more complicated to achieve, since
their leak tightness has to be ensured. If a porous foam is
created in a mould, the ability to separate between foam
and mould is also of great importance, once the foam needs
to be taken out. If it is generated as a free foaming mech-
anism, the separation rate of gas and foam should be lim-
ited to avoid disrupted structures. The simultaneous and
consecutive appearance of thermodynamic phenomena
during processing defines the properties and applications
of the created foam.
REFERENCES:
[1] A. Kauffmann, H. Schüle, Schäumen, in: Eyerer, P. et al. (Ed.) Polymer
Engineering – Technologien und Praxis; Springer, Berlin (u.a.), 2008,
pp. 286-295.
[2] F. A. Shutov, Blowing Agents for Polymeric Foams, in: D. Klempner, V.
Sendijarevic (Hrsg.) Polymeric Foams and Foam Technology, 2nd edi-
tion; Hanser, Munich, 2004, pp. 505-548.
[3] V. Altstädt, A. Mantey, Thermoplast-Schaumspritzgießen, Hanser,
München (2011).
POSTERS
OBTAINING DEFATTED SEEDS AND OIL RICh IN TOCOTRIENOLS FROM ANNATTO By SUPERCRITICAL ExTRACTION: STUDy OF PROCESS PARAMETERS, SCALE-UP AND ECONOMIC FEASIBILITy
245
OBTAINING DEFATTED SEEDS AND OIL RICh IN TOCOTRIENOLS FROM ANNATTO By SUPERCRITICAL ExTRACTION: STUDy OF PROCESS PARAMETERS, SCALE-UP AND ECONOMIC FEASIBILITy
carolina L. c. Albuquerque, M. Angela A. MeirelesDepartamento de Tecnologia de Alimentos,
Centro de Tecnologia e Desenvolvimento Regional, Universidade Federal da Paraíba – Campus V;
Distrito Industrial de Mangabeira, Via Local, s/n.,Quadra 252, Lote 501, 58.055-000, João Pessoa, PB, Brazil;
E-mail: [email protected]
This work presents a study of the supercritical fluid ex-
traction (SFE) of annatto oil to obtain defatted seeds and
extract rich in tocotrienols. The work consisted in studying
the process parameters, the scale-up and economic fea-
sibility. A review of the annatto agribusiness showed a
trend of using annatto due to the increasing consumer
demand for natural products because the seeds are rich
in tocotrienols, which are antioxidant and hypocholester-
olemic substances. However, the socioeconomic evalua-
tion of the producers, the recovery of higher quality extract,
and the use of process byproducts were found as the main
points that still needed to be improved. Supercritical Tech-
nology has the advantage of obtaining solvent-free extracts
and residue that add value to the products and byproducts
of the process. Thus, a preliminary study of economic fea-
sibility of the SFE process of annatto oil was carried out
using the available data in literature. The study showed
that the SFE of annatto oil was economically feasible with
no data optimized, since the cost of manufacturing (COM)
of extracts, for various industrial scales, were US$ 382.82/
kg (100 L), US$ 258.54/kg (500 L) and US$ 232.88/kg (1000
246 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
L). Therefore, optimized conditions of the process were
determined with the experimental assays at 313 and 333 K
and 20, 31, and 40 MPa. Larger amounts of oil were ob-
tained in 333 K/40 MPa. In these conditions, kinect ex-
periments were carried out and the COM of extracts was
estimated as a function of extraction time. The optimiza-
tion of process time decreased the COM for the capacities
100 and 500 L to US$ 124.58/kg and US$ 109.27/kg respec-
tively. Extract more concentrated in δ-tocotrienol, (14.6 ±
0.4)% was obtained at 313 K/20 MPa. In this condition, the
lowest bixin content was obtained in the extract, (0.9 ±
0.1)%. Therefore, an extract rich in functional substances
and defatted seeds, and rich in bixin for later extraction
were obtained with different feasible COM for industrial
scales. The overall extraction curves (OECs) determined
in a 5 L unit at 313 K/20 MPa showed that the scaling-up
criterion used in the SFE simulation to estimate the COM
was validated. The criterion was to keep constant the mass
of solvent to mass of feed ratio (S/F) and the solvent resi-
dence time obtained in laboratory scale. The OECs in both
scales had similar performance, with similar yield of ex-
tract and tocotrienols. The COM of the extracts was esti-
mated for different scenarios considering three different
stakeholders: investor, producer and colorant industries.
The raw material cost ranged from 0.00 to 2.20 US$/kg. In
the investor’s scenario, the best process time, from the
economic standpoint, was 105 minutes, with COM (115±5)
US$/kg for a 500 L and S/F of 8.7. For producer and indus-
try scenarios, the lowest COMs were (40±6) US$/kg, (15±2)
US$/kg, and (12±1) US$/kg, obtained at 28 minutes and
S/F of 3.1 for capacities of 50, 300 and 500 L, respectively.
The payback period ranged between 1-5 years for the pro-
ducer selling oil, waste, and defatted seed which has high
bixin content. The colorant industry use defatted seeds
POSTERS 247
for colorant production, and sells the oil. This study showed
that the SFE is economically feasible for units of at least
50L. Moreover, the process has the advantage of producing
seed with reduced or controlled oil content, and extract
with different concentrations of δ-tocotrienol, only by ad-
justing the operating conditions of the process.
ThE SUBCRITICAL WATER hyDROLySIS OF ANNATTO (BixA oRELLAnA L.) SEED RESIDUES
249
ThE SUBCRITICAL WATER hyDROLySIS OF ANNATTO (BixA oRELLAnA L.) SEED RESIDUES
sylvia c. Alcázar-Alay, Tania forster-carneiro, M. Angela A. Meireles
LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas);
R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]
Lignocellulosic residues are potential sources of bioener-
gy due to their high availability and high renewable po-
tential. Hydrothermal technologies, especially supercritical
and subcritical technologies, have delivered excellent re-
sults in the conversion of biomass by a hydrolysis process
that features the main advantage of using non-toxic sol-
vents and less time for conversion in comparison to other
methods of hydrolysis. Further, selectivity in the degrada-
tion of polysaccharides, proteins and lipids can be achieved
by varying the water properties with temperature and pres-
sure. The final products of hydrolysis are monosaccharides
and oligosaccharides, pentoses, hexoses, organic acids and
amino acids that are of significant commercial interest to
the food, chemical and energy industries. Defatted annat-
to seeds are obtained after the separation processes (the
extraction of active soluble compounds and pigments, ca-
rotenoids) and then are destined as the raw material for
use in the hydrolysis process. The separation of the fat
fraction is conducted using the supercritical fluid extraction
(SFE) method. In a subsequent process, the pigments are
separated from the defatted seed using a low-pressure
solvent extraction (LPSE) method, yielding a solid residue
with a larger fraction of the initial lignocellulosic biomass
250 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
that is free of pigments. Finally, the fermentable sugars in
the biomass are obtained after performing the subcritical
water hydrolysis of the defatted annatto. This study aims
to determine the key operating parameters for obtaining
the greatest percentage of fermentable sugars (water-
soluble oligomers, monomers) and amino acids, as well
as reducing the fractions of the degradation products of
hydrolysis and organic acids using subcritical water. The
main variables of the process are the temperature, pres-
sure, solvent mass to mass feed (S/F) ratio and use of CO2.
The hydrolysis products are analyzed for pH, total reduc-
ing sugars, monosaccharides and degradation products.
The S/F is analyzed in the range from 1/5 to 1/15 (the
highest ratios promote the dissolution of polysaccharides,
while lower ratios promote lower water consumption). The
effect of adding CO2 as a catalyst solvent is evaluated in
the proportion CO2/H
2O (v/v) 1/10. The temperature range
is from 420 to 520 K (the subcritical region) and the pres-
sure is between 10 and 20 MPa, which yields a condition
in which the pressure of the medium is higher than the
saturation pressure at all temperature conditions selected
for this study. The results obtained with pure water as
reaction medium are compared with the results obtained
using water + CO2 as the reaction medium.
ACKNOWLEDGEMENTS
The authors acknowledge the financial support from CAPES (DEA/FEA/
PROEX); and partial support from FAPESP (2009/17234-9 and 2012/10685-8)
is also acknowledged. S. C. Alcázar-Alay thanks CAPES for the Ph.D. as-
sistantship. M. A. A. Meireles thanks CNPq for the productivity grant
(302778/2007-1).
251
IDTq — A NEW RESEARCh GROUP LOCATED IN CORDOBA, ARGENTINA: PhASE EqUILIBRIUM, ExTRACTION, PURIFICATION AND MODELLING CAPABILITIES
Alfonsina E. Andreatta*, Juan M. Milanesio, Raquel E. Martini, M. f. Barrera vazquez
IDTQ – Grupo Vinculado PLAPIQUI – CONICET – FCEFyN, Universidad Nacional de Córdoba;
X5016GCA, Av. Vélez Sarsfi eld 1611, Córdoba, Argentina;E-mail: [email protected]
*Universidad Tecnológica Nacional, Facultad Regional San Francisco;
Av. de la Universidad 501, 2400, San Francisco, Córdoba, Argentina
IDTQ is a recently developed research group with a high
potential and mainly focused on supercritical technology
applied to the extraction of natural products and its use on
human health, and also applied to solve energy problems.
Plants with important properties for human health
accompany mankind from its origins. In spite of the great
evolution of health sciences, pathologies still exist without
a definitive cure or with therapies that cause undesirable
effects. Within this frame it is necessary to search new
therapeutic agents.
Traditional processes of extraction and purification
of natural products are: pressing, hydro-distillation, steam
stripping and liquid organic solvent extraction. These tra-
ditional methods require high residence time, big quantities
of solvent and they present low selectivity. New techniques
such as the application of supercritical fluids [1], micro-
wave assisted extraction [2-4], ultrasound [4,5] and pres-
surized water [6,7] are among the new methods used in
the industrial field to recover the bioactive compounds
present in natural products. In this sense, we present dif-
252 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
ferent natural products that were used to test these new
extraction methods. The recovery of anthraquinones from
cegadera, tannin from grapeseed, catechins from green
tea and different bioactive compounds were studied in our
lab.
To model the equilibrium of these mixtures the use
of a group contribution approach is a logical choice. In
this way a group-contribution with association equation
of state GCA-EOS [8] was applied to represent phase equi-
librium data on mixtures containing the compounds in
study with different solvents in a high range of condition
including supercritical conditions. The extension of the
GCA-EoS model will allow to represent a large set of nat-
ural products with complex chemical structures, and to
evaluate traditional and supercritical processes using the
equation predictive capability.
REFERENCES
[1] D. J. Miller, S.B. Hawthorne, J. Chemical & Engineering Data, 45 (2000)
315-318.
[2] A. Navarrete Muñoz, Tesis Doctoral. Universidad de Valladolid, 2010.
[3] B. G. Terigar, S. Balasubramanian, C. M. Sabliov, M. Lima, D. Boldor,
J. Food Engineering, 104 (2011) 208-217.
[4] S. Hemwimon, P. Pavasant, A. Shotipruk, Separations and Purification
Technology, 54 (2007) 44-50.
[5] M. Dabiri, S. Salimi, A. Ghassempour, A. Rassouli, M. Talebi, J. Sepa-
ration Science, 28 (2005) 387-396.
[6] M. D. Luque de Castro, M.M. Jiménez-Carmona, V. Fernández-Pérez,
Trends in Analytical Chemistry, 18 (1999) 708-716.
[7] D. J. Miller, S. B. Hawthorne, A. M. Gizir, A. A. Clifford, J. Chemical &
Engineering Data, 43 (1998) 1043-1047.
[8] H. P. Gros, S. Bottini, E. A. Brignole, Fluid Phase Equilibria, 116 (1996)
537-544.
ThE SUPERCRITICAL FLUID ExTRACTION OF ANTIOxIDANT COMPOUNDS FROM ABIU SKIN
253
ThE SUPERCRITICAL FLUID ExTRACTION OF ANTIOxIDANT COMPOUNDS FROM ABIU SKIN
Elena M. Balboa, herminia Domínguez Departamento de Enxeñería Química,
Universidade de Vigo; Campus Ourense, Edifi cio Politécnico, As Lagoas, 32004 Ourense, Spain
CITI-Universidade de Vigo; Parque Tecnolóxico de Galicia, Rúa Galicia 2, 32900 Ourense, Spain
Angela M. farías-campomanes, M. Angela A. MeirelesLASEFI/DEA/FEA (School of Food Engineering),
UNICAMP (University of Campinas);R. Monteiro Lobato, 80, 13083-862 Campinas, São Paulo, Brazil;
E-mail: [email protected]
carlos v. Lamarão pereira, valdir f. veiga Jr. Departamento de Química, ICE,
Universidade Federal do Amazonas; Av. Gal. Rodrigo Octávio, 3.000, Coroado II, Manaus, Brazil
Abiu (Pouteria caimito) is a tropical fruit that is native to
the Amazonian region of Brazil. Abiu is predominantly
eaten raw or used for the preparation of juice or ice cream.
The skin of abiu is not usable, so it is considered to be a
residue of the peeling process. However, the skin contains
a significant amount of oils and phenolic compounds. The
abiu fruit has traditionally been used to relieve coughs,
bronchitis and other pulmonary afflictions but also as as-
tringent, anti-anemic and anti-inflammatory properties.
Additionally, some studies have shown that abiu has a high
phenolic content [1] and strong α-amylase and α-gluco-
sidase inhibitory activities that reduce postprandial blood
glucose levels [2]; as a result, it is believed that the skin
of abiu also might possess interesting properties. Super-
critical fluid extrac tion (SFE) is a clean process that can
be used to obtain high-quality extracts from plants or
254 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
derivatives. Carbon dioxide is the most commonly used
solvent because it is cheap, environmentally friendly and
generally recognized as safe (GRAS). Further, carbon diox-
ide has high diffusivity, allows for the recovery of solvent-
free extracts because of its gaseous form at room temperature,
and allows for the extraction of thermally labile or easily
oxidized compounds because the process is carried out at
low temperatures using a non-oxidizing medium [3]. The
aim of this study is to determine the best conditions of
antioxidant recovery from the skin of abiu by using super-
critical carbon dioxide at varying conditions of pressure
and temperature. Due to the lack of previous literature
results on the SFE extraction of this raw material, a wide
range of pressures (15, 20, 25, 30 and 35 MPa) and tem-
peratures (40, 50 and 60 °C) were studied. The assays were
performed in duplicate. The extracts were evaluated for
global yield and antioxidant activity based on the coupled
reaction of β-carotene and linolenic acid [4]. The abiu fruit
was processed, and the residual skin was collected, dried,
milled and stored at -18 °C in a plastic bag for protection
from light. The extractions were carried out in a commercial
SFE system equipped with an electric oven and a pneu-
matic pump (Spe-ed SFE Laboratory System, 7071, Applied
Separations, Allentown, USA). Because of the antioxidant
capacity and phenolic content of abiu skin, the extracts
are probable candidates for use as active ingredients in
pharmaceutical, functional food and cosmetic industries.
ACKNOWLEDGMENTS
This work is part of the Ph.D. thesis of E. Balboa. E. Balboa thanks the
Spanish Ministry of Education and Science for her FPI grant (BES-2010-
041807). A. M. Campomanes-Farias thanks CAPES/PEC-PG for the Ph.D.
assistantship. The authors are thankful for the financial support from CNPq,
CAPES-PROEX.
POSTERS 255
REFERENCES
[1] S. A. Assis, J. C. R. Vellosa, I. L. Brunetti, N. M. Khalil, K. M. D. S. C.
Leite, A. B. G. Martins, O. M. M. D. F. Oliveira, Antioxidant activity,
ascorbic acid and total phenol of exotic fruits occurring in Brazil, Inter-
national J. Food Sciences and Nutrition, 60, 5 (2009) 439-448.
[2] P. M. De Souza, P. M. De Sales, L. A. Simeoni, E. C. Silva, D. Silveira, P.
De Oliveira Magalhães, Inhibitory activity of α-amylase and α-glucosidase
by plant extracts from the Brazilian cerrado, Planta Medica, 78, 4 (2012)
393-399.
[3] M. Herrero, J. A. Mendiola, A. Cifuentes, E. Ibáñez, Supercritical fluid
extraction: Recent advances and applications, J. Chromatography A,
1217, 16 (2010) 2495–2511.
[4] P. F. Leal, N. B. Maia, Q. A. C. Carmello, R. R. Catharino, M. N. Eberlin,
M. A. A. Meireles, Sweet basil (Ocimum basilicum) extracts obtained
by supercritical fluid extraction (SFE): global yields, chemical compo-
sition, antioxidant activity, and estimation of the cost of manufacturing,
Food Bioprocess Technology 1, 4 (2008) 326-338.
ANTIOxIDANT, hyPOLIPEMIANT AND ANTI-OBESITy ACTIVITIES OF cAsEARiA syLvEsTRis ExTRACTS OBTAINED FROM SFE AND LPE, AND ExPERIMENTAL PhASE EqUILIBRIUM BEhAVIOR DETERMINATION
257
ANTIOxIDANT, hyPOLIPEMIANT AND ANTI-OBESITy ACTIVITIES OF cAsEARiA syLvEsTRis ExTRACTS OBTAINED FROM SFE AND LPE, AND ExPERIMENTAL PhASE EqUILIBRIUM BEhAVIOR DETERMINATION
patícia Benelli, sibele R. Rosso comim, Evelin c. Azevedo, Rozangela c. pedrosa,
sandra R. s. ferreiraFederal University of Santa Catarina (UFSC), EQA/CTC; CP 476 – Trindade, 88040-900, Florianópolis, SC, Brazil;
E-mail: [email protected]
Antioxidants, either as additives or as pharmaceutical sup-
plements, can end radical reactions in vivo which can dam-
age essential molecules such as nucleic acids and proteins.
The natural antioxidant compounds have been isolated
from different kind of natural products, including flavonoids,
phenolic acids, terpenes, tocopherols and phospholipids.
These compounds can also be responsible for hypolipemi-
ant and anti-obesity activities, which mean compounds
used for hyperlipidemia treatments (excess of cholesterol,
triglycerides and glucose levels) and excess of weight gain.
Casearia sylvestris is a native medicinal plant in Brazil,
Peru, Argentina, Uruguay and Bolivia. The leaves of the
plant are popularly used in folk medicine as antiseptic,
topical anaesthetic, antitumor and antiulcer agents, and
to heal skin wound diseases. In the Casearia extracts there
are substances of great interest, such as coumarins, fla-
vonoids and diterpenes, especially clerodane diterpenes
as casearins and casearvestrins, which are bioactive with
excellent cytotoxic and antitumor potential. Supercritical
fluid extraction (SFE) is an alternative process to conven-
tional extractions in various applications due to the pos-
258 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
sibility to obtain solvent-free extracts and the use of low
extraction temperatures, warranting the process selectivi-
ty towards the bioactive compounds. Considering the im-
portance of these compounds the knowledge of the phase
equilibrium of natural extracts in supercritical fluids, ob-
tained by experimental measurements, is fundamental for
determination of optimal conditions for separation and
precipitation processes conducted at higher pressures,
especially for food and pharmaceutical industries. The aim
of the present project is to obtain and compare the extract
attainment from C. sylvestris by SFE with CO2 and CO
2
with co-solvent and low pressure extractions as Soxhlet
(SOX) and maceration (MAC) with different solvents. The
techniques efficiency was compared in terms of process
yield and antioxidant capacity, evaluated by DPPH assay,
β-carotene bleaching method and total phenolic content
(TPC). The anti-obesity and hypolipidemic effects were
also evaluated in vivo submitting Mus musculus Balb/c
mice to a high-fat diet combined with C. sylvestris extracts
during 30 days, monitoring the animals’ weight during the
treatment and the final total serum cholesterol, triglycerides
and glucose levels. The TPC presented maximum values
of 169.4±0.6 mgGAE/g (SOX-ETOH) and 135±4 mgGAE/g
(MAC-ETOH). The antioxidant potential by DDPH meth-
od resulted in effective concentration at 50% (EC50) val-
ues of 254±3 µg/mL (SFE 50 ºC/200 bar+11% ETOH) and
245±4 µg/mL (SFE 300 bar/50 °C+8% ETOH) and the
β-carotene method presented values of 108±3% for SFE
sample obtained at 50 ºC/300 bar+5% ETOAC and 110±1%
obtained at 50 ºC/200 bar+2% ETOAC extract, after 120
minutes-reaction. The best anti-obesity results were ob-
tained for the diet using SFE extracts 300 bar/50 ºC+5%
ETOH and 300 bar/50 ºC+5% ETOAC among the extracts
tested. The lowest cholesterol levels were provided by
POSTERS 259
SOX-ETOH and SOX-ETOAC extracts and the highest
glucose reduction were observed by treating the animals
with SFE 300 bar/50 ºC and SFE 300 bar/50 ºC+5% ETOH
extracts. The groups treated with extracts obtained at SFE
300 bar/50 ºC+5% ETOH and SOX-ETOAC presented low-
er triglycerides levels. The continuation of this work will
perform the antioxidant evaluation by ABTS radical and
lipid peroxidation in vitro (TBARS) methods and by the
achievement of the extracts chemical profile by gas chro-
matography coupled to mass spectrometry analysis (GC-
MS), in order to prove the presence of important compounds
with biological activity. Also, the investigation of the phase
equilibrium behavior of systems composed by C. sylvestris
extract, organic solvent and supercritical CO2 will be held
by means of the static synthetic method to afford infor-
mation for the separation and precipitation/encapsulation
processes.
ThE USE OF SUPERCRITICAL FLUID ChROMATOGRAPhy (SFC) IN ThE ANALySIS OF PETROLEUM, GASOLINE AND KEROSENE
261
ThE USE OF SUPERCRITICAL FLUID ChROMATOGRAPhy (SFC) IN ThE ANALySIS OF PETROLEUM, GASOLINE AND KEROSENE
Endler Marcel Borges, Mauricio A. Rostagno, Rodrigo Bisaia, guilherme Romão,
M. Angela A. MeirelesLASEFI/DEA/FEA (School of Food Engineering),
UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil;
E-mail: [email protected]
flávio c. Albuquerque CENPES – PETROBRAS R&D Center;
Av. Horácio de Macedo, 950, Cidade Universitária, 21941-915, Rio de Janeiro, RJ, Brazil
As an analytical technique, supercritical fluid chromatog-
raphy (SFC) is complementary to both gas chromatography
(GC) and liquid chromatography (LC). SFC can be applied
to materials that are too heavy to meet the volatility and
thermal stability requirements for GC. Supercritical fluids
possess a combination of gas-like and liquid-like proper-
ties, which enables the elution of high-molecular-weight
materials and faster solute transport within the column.
This property also results in shorter analysis time for SFC
relative to HPLC [1,2].
Hydrocarbon group separation is a very difficult task
because high selectivity toward very similar molecules is
required [3]. SFC with flame ionization detection (FID) has
been shown to work well for hydrocarbon group analysis
[4]. The American Society of Testing and Materials (ASTM)
has accepted the use of SFC for the determination of aro-
matic contents of jet and diesel fuels [2,4] (ASTM D 5186-
96). However, this method is not applicable to crude oil
because crude oil is significantly more complex in com-
262 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
position than either jet or diesel fuel. For example, crude
oil contains heavy compounds, such as asphaltenes, res-
ins and several polar compounds.
Evaporative light scattering detection (ELSD) was
originally designed for LC for the detection of non-volatile
compounds by mass [1]. In ELSD, the eluent is nebulized
by a gas stream followed by solvent evaporation, typical-
ly in a heated drift tube. The remaining micro particles of
the non-volatile solid or liquid analyte are then passed
through a beam of light. The incident light is scattered by
the particles and then collected by a photomultiplier ap-
paratus, which generates the signal. Because the detec-
tion mechanism does not rely on the optical properties of
the compound, ELSD is considered a universal detector
and is ideal for detecting analytes without UV chromo-
phores [5].
SFC-FID has been extensively used in the analysis
of petrol and petrol derivatives due to the lack of a sensi-
tive and universal detector that can be used for this pur-
pose. However, the development of the ELSD detector has
changed this situation; in this project, we present a SFC-
ELDS method for the analysis of crude oil and oil derived
products. Our main goal is develop a system and the nec-
essary methodology for the separation of the different com-
pound classes present in crude oil and oil products.
The experimental conditions were optimized using
a test mixture containing hexadecane, toluene, tetralin
(1,2,3,4-tetrahydronaphthalene), naphthalene, pyrene, ben-
zo(a)pyrene and anthracene [6] (test mixture 1). After meth-
od optimization, real samples of kerosene, diesel and petrol
were analyzed.
The separation of the constituents in petrol and pet-
rol derivatives was optimized by varying several experi-
mental conditions, such as the column [Spherisorb S5W
POSTERS 263
(10 x 250 mm, 5 µm), Spherisorb CN (10 x 250 mm, 5 µm),
Spherisorb SCX (10 x 250 mm, 5 µm), Viridis SFC 2-Eth-
ylpyridine (10 x 150 mm, 5 µm)], the temperature (20-60 ºC),
the back pressure (100-300 MPa) and the flow rate (2-12
mL min-1).
The response dependence of ELSD on several com-
mon experimental parameters, including gas flow, co-sol-
vent percentage, evaporation and nebulization temperatures,
was tested with and without a column for each compound
in test mixture.
This work was carried out using modular equip-
ment. The unique configuration of this equipment makes
possible the elution (flush) of three consecutive connected
columns; additionally, by changing the configuration it is
possible to individually backflush each column to collect
selectively each fraction that is separated. The first stage
of method development was initially carried out using one
column without back-flush. The next stage included the
evaluation of two columns with individual back-flush ca-
pabilities. Finally, the last stage included the use of all
three columns connected in series, followed by the se-
quential backflush of each column.
The efficacy of our SFC-ELSD method was demon-
strated for the analysis of several petrol, gasoline and ker-
osene samples, which were provided by the CENPES/
PETROBRAS.
ACKNOWLEDGEMENTS
This work was carried out through cooperation between LASEFI/DEA/FEA/UNICAMP and CENPES/PETROBRAS. The authors acknowledge the finan-cial support from the Brazilian National Agency of Petrol [Agencia Nacion-al do Petróleo (ANP)].
REFERENCES
[1] B. N. Barman, V. L. Cebolla and L. Membrado, Critical reviews in ana-lytical chemistry, 30 (2000) 75-120.
264 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
[2] L. T. Taylor, Analytical chemistry, 82 (2010) 4925-4935.
[3] R. M’Hamdi, D. Thiéabaut and M. Caude, J. High Resolution Chroma-
tography, 20 (1997) 545-554.
[4] B. E. Richter, B. A. Jones and N. L. Porter, J. chromatographic science,
36 (1998) 444-448.
[5] E. Lesellier, A. Valarché, C. West and M. Dreux, J. Chromatography A,
1250 (2012) 220-226.
[6] T. Dutriez, D. Thiébaut, M. Courtiade, H. Dulot, F. Bertoncini and M. C.
Hennion, Fuel, 104 (2013) 583-592.
scCO2 POST-PROCESSING OF MATERIALS FOR BIOMEDICAL APPLICATIONS
265
scCO2 POST-PROCESSING OF MATERIALS FOR BIOMEDICAL APPLICATIONS
Mara E. M. Braga, Ana M. A. Dias, hermínio c. de sousa
CIEPQPF – Chemical Engineering Departament, FCTUC, University of Coimbra;
Rua Silvio Lima, s/nº, Pólo II, Pinhal de Marrocos, 3030-790, Coimbra, Portugal;
E-mails: [email protected], [email protected], [email protected]
Post-processing of finished commercially available poly-
mer-based devices is a recent and attractive approach for
the development of multifunctional biomedical devices
and implants, drug release systems and tissue scaffolds.
Materials that are intended to be used for biomedical ap-
plications should satisfy a wide range of requirements in
terms of their biocompatibility/toxicity, surface chemistry/
morphology, porosity and pore morphology/interconnec-
tivity, mechanical properties, degradation and bio-absorp-
tion rates and replacement rate by neo-tissues. The use
of scCO2 for post-processing purposes is a particular ad-
vantageous example which has been widely employed as
a morphological, porogenic, foaming, viscosity reducer
or a plasticizer agent for a wide range of applications that
include polymer/composite processing, micronization of
biocompatible polymers, encapsulation, impregnation or
deposition of bioactive substances into solid matrices
(polymeric/ceramic/composite), and extraction of unde-
sired compounds from the synthesized materials. Some of
these processes such as scCO2-assisted impregnation/
deposition method have an advantage for precise incorpo-
ration of bioactive substances into polymeric, inorganic
266 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
and composite materials in a short time and without the
presence of harmful solvent residues. This process permits
to load previously prepared biomaterials or even biomed-
ical articles/devices without interfering with their intrinsic
material properties during the manufacture and/or process-
ing. The ability of polymeric devices to carry and release
specific biological and/or synthetic bioactive substances,
in a temporal- and in a 3D-controlled way, benefits the
involved biological processes when they are used specif-
ically to repair, to regenerate or even to replace a lost func-
tion of a tissue and/or organ involving the use of cells is
studied in the tissue engineering field. Over the last years
our research group has been studying the impregnation/
deposition method on finished devices. Examples of scCO2
processed biomaterials include contact and intraocular
lenses, wound dressings, bioactive glasses, composites,
scaffolds, etc. The impregnation/deposition of acetazol-
amide and timolol maleate into commercial soft contact
lenses to produce anti-glaucoma drug-loaded contact lens-
es was easily obtained by changing the operational pres-
sure, temperature, processing time and depressurization
rate conditions, to control the lenses drug loading capac-
ities. This feature permits to adjust the final drugs release
levels into specific and desired therapeutic limits without
affecting the main properties of ophthalmic devices such
as oxygen permeability, glass transition, contact angle and
optical properties. Another example include the development
of bioactive glasses (that will be used as bone substitute)
loaded with dexamethasone, for which post- processing
became an important step since the synterization process
(required to produce glasses) restrains drug inclusion during
the synthesis to avoid the thermo- degradation of the drug.
This drug deposition method improved the biological ac-
tivities of the prepared bioglasses, increased cell viability
POSTERS 267
and presented osteogenic and anti-inflammatory prop-
erties, as confirmed by in vitro cell assays. These works
dem onstrate that the above referred scCO2-based post-
processing methods can be very useful for the preparation
of polymeric based materials with tunable physicochem-
ical, thermomechanical, morphological and drug release
properties, suitable for biomedical applications.
MEASUREMENT OF LIqUID-VAPOR AND LIqUID-LIqUID-VAPOR EqUILIBRIUM IN CO2 + ORGANIC + IONIC LIqUID TERNARy SySTEMS
269
MEASUREMENT OF LIqUID-VAPOR AND LIqUID-LIqUID-VAPOR EqUILIBRIUM IN CO2 + ORGANIC + IONIC LIqUID TERNARy SySTEMS
Roberto canales, Joan f. BrenneckeUniversity of Notre Dame;
182 Fitzpatrick Hall, 46556, Notre Dame, IN, USA; E-mail: [email protected]
Ionic liquids (ILs) are among the options for replacing con-
ventional volatile organic solvents in industry, due to their
interesting characteristics, such as low volatility, high
thermal stability and the possibility of tuning their phys-
ical and chemical properties (high number of cation-anion
combinations). However, separation of components from
ILs is a challenge since distillation, heating and liquid-liq-
uid extraction are not the best options if we need to pro-
cess thermolabile compounds and to avoid using volatile
organic solvents in the processes. Here we explore the idea
we first suggested in 2002 [1] of using CO2 to induce liq-
uid-liquid phase splits in IL + organic systems.
Originally we showed that polar organics and wa-
ter can be separated from ILs using CO2 [2-4]. For instance,
when methanol is added to [bmim][PF6] it forms a single
phase liquid mixture. Then, CO2 is added to the liquid
phase at constant temperature and the increasing pres-
sure results in a high solubility of the CO2 in the organic
+ IL liquid mixture. This also increases the volume of the
liquid phase and eventually induces a phase split to obtain
liquid-liquid-vapor equilibrium (LLV). The pressure at which
this occurs is called the “cloud point”. If more CO2 is add-
ed to the system forming a LLV equilibrium, there is a
pressure where the organic-rich phase disappears, dis-
270 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
solving the organic compound into the supercritical CO2
phase. This is called the “merging point”.
This work is focused on measuring the separation
of toluene from four different ILs based on the bis(trifluoro-
methylsulfonyl)imide ([Tf2N]-) anion. Cations are 1-hexyl- 3-
methylimidazolium ([hmim]+), 1-hexyl-3-methylpyridinium
([hmpy]+), triethyloctyl phosphonium ([P2228]+) and tri-
hexyltetradecyl phosphonium ([P66614]+). Two different
apparatuses, a modification of those shown in another work
from our group [4] are presented for measuring the com-
position in the different phases: a stoichiometric appara-
tus for solubility of CO2 in the single liquid phase mixture
until the cloud point appears and an analytical apparatus
for sampling the phases in LLV equilibrium, which ends
in the merging point of the mixture as the pressure is in-
creased. Solubility of CO2 in the toluene + IL mixture is
measured at 298 K and 313 K (also 333 K for [hmim][Tf2N])
and pressures up to 8 MPa, with initial IL mole fraction of
0.30, 0.50 and 0.70. Results are compared with binary sol-
ubilities of CO2 in the different ILs and toluene.
The solubility of CO2 in the liquid mixture increas-
es with increasing pressure and decreases at higher tem-
peratures. The same trend is observed for binary systems
of CO2 in ILs. The solubility of CO
2 in toluene is lower than
in the pure IL but a crossover is reached at an intermedi-
ate pressure. The solubility of CO2 in liquids mixtures of
toluene + IL increases as the initial concentration of IL is
increased. The cloud point pressure is higher at higher
temperatures and lower initial IL composition. The merg-
ing points increase at higher temperatures and we find
that the values are not dependent on the initial IL concen-
tration. Lower cloud point pressures are observed when
using [hmim][Tf2N] and [hmpy][Tf2N], while slightly high-
er pressures are required for [P2228][Tf2N]. [P66614][Tf2N]
POSTERS 271
shows the largest CO2 solubility in the binary and ternary
systems, but this IL exhibits a very high cloud point pres-
sure.
REFERENCES
[1] A. M. Scurto, S. N. V. K. Aki, J. F. Brennecke, J. American Chemical
Society, 124 (2002) 10276-10277.
[2] A. M. Scurto, S. N. V. K. Aki, J. F. Brennecke, Chemical Communica-
tions, (2003) 572-573.
[3] B. R. Mellein, J. F. Brennecke, J. Physical Chemistry B, 111 (2007)
4837-4843.
[4] S. N. V. K. Aki, A. M. Scurto, J. F. Brennecke, Industrial & Engineering
Chemistry Research, 45 (2006) 5574-5585.
ThE RECOVERy OF hIGh-VALUE-ADDED PRODUCTS FROM PRESSED PALM FIBER USING INTEGRATED SUPERCRITICAL TEChNOLOGy: ExTRACTION AND hyDROLySIS
273
ThE RECOVERy OF hIGh-VALUE-ADDED PRODUCTS FROM PRESSED PALM FIBER USING INTEGRATED SUPERCRITICAL TEChNOLOGy: ExTRACTION AND hyDROLySIS
fiorela p. cardenas-Toro, Tania forster-carneiro, M. Angela A. Meireles
LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas);
R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]
The use of agroindustrial residues has received significant
attention in recent years because such residues can be
used as a source of value-added products, such as bioac-
tives for the food industry and fermentable sugars for sec-
ond-generation ethanol. Supercritical technology provides
an interesting option for the sustainable utilization of bio-
mass as an alternative to conventional solvents. Supercrit-
ical fluid extraction (SFE) and pressurized liquid extraction
(PLE) techniques use solvents, such as CO2 and ethanol,
at elevated pressure and temperature to enhance extrac-
tion performance in comparison with soxhlet extraction
in terms of selectivity. Subcritical water hydrolysis (Sub-
WH) possesses the advantages of short conversion times
and low residue generation; however, a deep understand-
ing of the behavior of this technique is needed for sugar
production optimization. Pressed palm fiber is a residue
obtained from the oil palm industry and contains bioactive
compounds, such as carotenoids (α- and β- carotene), which
are important additives for antioxidant properties. Addi-
tionally, this residue contains cellulose and hemicellulose,
which are sources of fermentable sugars. The objective of
this work was to study integrated SFE or PLE for the re-
274 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
covery of extracts rich in carotenoids and, subsequently,
SubWH for the recovery of hydrolysates that are rich in
fermentable sugars. First, the integrated process of SFE
and SubWH was studied. The effect of the operational pa-
rameters (pressure and temperature) on the SFE of carot-
enoids was investigated. The highest SFE extract yield
was observed at 328 K and 20 MPa (2.6% d.b.), while the
highest yield for carotenoid content was obtained at 318 K
and 15 MPa (800 ppm in the extract). The defatted, pressed
palm fiber was used as a raw material for the SubWH ex-
periments. The optimal condition for a product possessing
high sugar formation and low sugar degradation was found
at 523 K, 15 MPa, a solvent/feed of 120 and a space-time
of 2.5 min (yield of 23%, conversion of 84.9%). Second, an
integrated process of PLE and SubWH was investigated
based on the use of a new lot of pressed palm fiber. A
central composite rotational design was carried out to eval-
uate the effects of pressure and temperature on carotenoid
recovery. The continuous increment of global yield was
observed with the increment of temperature and pressure,
and the highest carotenoid recovery was found at 328 K and
4 MPa (4,000 ppm in the extract). Subsequent SubWH ex-
periments for kinetic studies at 523 K and 15 MPa are un-
der evaluation. Additionally, an economic analysis of the
proposed integrated processes will be evaluated. The in-
tegration of extraction and hydrolysis provides a promising
method for the recovery of carotenoids and fermentable
sugars from pressed palm fiber.
ACKNOWLEDGEMENTS
The authors thank the Agropalma S.A. Company for supplying the pressed palm fiber residues and acknowledge the financial support from (DEA/FEA/PROEX), CNPq (560914/2010-5) and FAPESP (2011/19817-1 and 2012/10685-8). F. P. Cardena-Toro thanks CAPES/PEC-PG (5945100) for the Ph.D. as-sistantship, and M. A. A. Meireles thanks CNPq for the productivity grant (302778/2007-1).
SUPERCRITICAL FLUID TEChNOLOGIES, INC.
275
SUPERCRITICAL FLUID TEChNOLOGIES, INC.
Thayane carpanedo LabSolutions;
R. Marquês de Olinda, 680, 04277-000 São Paulo – Ipiranga, SP, Brazil; E-mail: [email protected]
Rudy Baskette, Kenneth J. JamesSupercritical Fluid Technologies, Inc.;
19711 Newark, DE, USA;E-mail: ken.james@supercriticalfl uids.com
Supercritical fluid extraction (SFE) is an excellent method
to concentrate flavors, fragrances, essential oils, biologi-
cally active compounds and materials of interest from
flowers, leaves, fruits, bark, roots, buds, seeds, etc. SFE
produces oils with standardized concentration of active
ingredients and products with much higher yield and pu-
rity concentration of active ingredients and products. SFE
also produces oils of higher quality than traditional meth-
ods and with less creation of artifacts. Hops can add re-
markable depth to the flavor profile of a beer by amplifying
fruity, spicy, woodsy, or citric flavors. This experiment will
demonstrate that the SFT-110 SFE Unit can use supercrit-
ical carbon dioxide to separate aromatic and bitter hop
components.
277
VOLATILE OIL ExTRACTION FROM TURMERIC (cuRcuMA LongA L.) By SUPERCRITICAL CARBON DIOxIDE: STUDy OF ThE ExTRACTION IN BEDS OF DIFFERENT GEOMETRIES AND OPERATIONAL CONFIGURATIONS
pedro ivo n. de carvalho, Mauricio A. Rostagno, M. Angela A. Meireles
LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas);
R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]
Production of extracts from vegetal matrices with biolog-
ical properties has attracted great interest of food, cos-
metic, and pharmaceutical industries. Within this demand,
the extraction process using supercritical carbon dioxide
(SFE-CO2) has been shown being a technically and eco-
nomically feasible technology for the extraction of several
substances. It has some advantages over conventional
extraction techniques, both in terms of yield and quality
of the extract. Thus, the first objective of this work is the
application of SFE-CO2 in the optimization of volatile oil
extraction from turmeric in laboratorial scale. This oil is
rich in ar-turmerone, compound that has been reported in
the literature by presenting some bioactive properties, such
as, anti-inflammatory, antimicrobial, antioxidant and an-
ticarcinogenic activity [1].
Currently, in the SFE-CO2 context it becomes im-
portant the generation of knowledge and methodologies
of scale-up towards the industrial application of the SFE-CO2
process. However, some situations that may take place in
extractors of industrial scale, and even, pilot scale, such
as bed porosity, temperature gradient and inefficient sol-
278 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
vent dispersion [2] have not been taken into account by
the most simple criteria of scale-up. For instance, in tall
extraction columns axial dispersion can occur and in ex-
tractors of larger diameters can result in heterogenic extrac-
tion due to radial effects inside of extractor [3]. In this work
is proposed the study of bed geometry influence (height
and diameter of the extractor), as well as of variations
associated with this factor (as temperature gradient and
solvent distribution), in the extraction kinetic of the tur-
meric volatile oil.
The installation of a continuous SFE process is oth-
er important point in industrial scale. Continuous process
of extraction is possible and avoids “dead” times in the
process due to the steps of de-pressurization, unloading
of exhausted substrate, loading of fresh substrate, and
re-pressurization [4]. In a extraction plant equipped with
two or more extractors, while one extractor is being reload
with fresh raw material, the other one (or the others) is
working [5]. With the extractors positioned in parallel the
solvent stream is alternating between the columns in each
period wherein the yield intended is reached. In this con-
figuration mode, just one extractor is in operation. With
two or more extractors positioned in series, the process is
called counter-current. The supercritical carbon dioxide
stream is put on in contact with the substrate more ex-
hausted and then successively with the substrate more
rich in solute. This work aims to define which the best
configuration to the extraction columns (extractors in se-
ries or in parallel) taking into account technical and eco-
nomical parameters using turmeric as raw material.
The compounds present in the extract of the volatile
oil will be identified by gas chromatography-mass spec-
trometry (GC-MS) and will be quantified by gas chroma-
tography with flame ionization detection (GC-FID). Finally,
POSTERS 279
the cost of manufacturing of extracts will be estimated
using the simulator SuperPro Designer® 8.5.
ACKNOWLEDGEMENTS
Authors are grateful to CNPq (470916/2012-5) for the financial support;
partial support from FAPESP (2012/10685-8) is also acknowledged. Pedro Ivo
N. de Carvalho thanks CNPq for the MSc. assistantship. M. A. A. Meireles
thanks CNPq for the productivity grant (302778/2007-1).
REFERENCES
[1] B. Chempakam, V. A. Parthasarathy, Turmeric, in: V. A. Parthasarathy, B.
Chempakam, T. J. Zachariah (Ed.) Chemistry of Spices; CAB Interna-
tional, 2008.
[2] J. M. del Valle et al., Supercritical CO2 processing of pretreated rose-
hip seeds: effect of process scale on oil extraction kinetics, J. Super-
critical Fluids, 31(2) (2004) 159-174.
[3] G. Brunner, Gas extraction. An introduction to fundamentals of super-
critical fluids and the application to separation processes; Springer,
New York, 1994.
[4] R. Eggers, P. T. Jaeger, Extraction Systems, in: G. Liadakis, C. Tzia (Ed.)
Extraction Optimization in Food Engineering; CRC Press, 2003.
[5] G. A. Núñez, C. A. Gelmi, J. M. del Valle, Simulation of a supercritical
carbon dioxide extraction plant with three extraction vessels, Com-
puters and Chemical Engineering, 35(12) (2011) 2687-2695.
PRE-SALT RESERVOIR FLUID BEhAVIOR
281
PRE-SALT RESERVOIR FLUID BEhAVIOR
osvaldo chiavone-filho Department of Chemical Engineering,
NT/PPGEQ/NUPEG, Federal University of Rio Grande do Norte (UFRN); Campus Universitário, Lagoa Nova,
59066800, Natal, Rio Grande do Norte, Brazil; E-mail: [email protected]
Eduardo Mach Queiroz, fernando Luiz pellegrini pessoaFederal University of Rio de Janeiro;
CT, BL E, SL 209, Ilha do Fundão, 21949900, Rio de Janeiro, RJ, Brazil; E-mails: [email protected], [email protected]
The reserves of oil and gas in the pre-salt region are esti-
mated in Brazil to be huge and the best are the expectations.
This research work may initially be called “thermodynam-
ic and transport fluid behavior of reservoir mixtures in the
pre-salt conditions of temperature, pressure and compo-
sition”. The presence of species in supercritical conditions
and in significant amounts should be taken into account,
that is the case of carbon dioxide and methane. This fact
plays certainly influence in reservoir behavior and this
research work aims to describe this effect through two
lines, i.e., phase equilibrium thermodynamics and flow
process simulation. The methodology was basically direct-
ed to experimental data collection, study and definition
of the mathematical models, and simulators, or computa-
tional tools, to describe the thermodynamic and transport
fluid behavior of reservoir mixtures in the pre-salt condi-
tions of temperature, pressure and composition. The char-
acterization of the fluid was initially restricted to ten species:
methane, ethane, propane, carbon dioxide, water, sodium
chloride, calcium carbonate, cyclohexane, n-decane and
282 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
hexacosane. The conditions of temperature and pressure
of interest are initially 60 to 120 ºC and 120 to 700 bar,
respectively. Therefore, species like methane, ethane, pro-
pane and carbon dioxide are in supercritical (SC) condi-
tions. Another relevant information is that there exists
wells of the pre-salt in operation that present outstanding
production of 20 mil barrels per day, but at the same time
many other wells show production much lower than ex-
pected. Thus a better understanding of the system in con-
ditions of the pre-salt may explain these results of low
production that are contradicting the expectations of the
pre-salt. Preliminary simulations using a cubic equation
of state are presenting and demonstrate that an adequate
approach is able to give a panoramic view of the thermo-
dynamic and transport properties. Results of phase en-
velope, multiphase flash with stability test, density and
viscosity are presented. It may be pointed out that the
presence of carbon dioxide with concentration in the order
of 15% plays influence in the studied properties of the mix-
ture. Commercial simulators usually applied in the de-
scription of reservoirs do not consider the presence of
supercritical species in the evaluation of the thermody-
namic and transport properties and this phase concept is
fundamental in the pre-salt mixtures of severe conditions
of pressure and temperature. Beyond the preliminary re-
sults of simulation, a brief revision of the adequate ther-
modynamic models to describe the pre-salt fluid behavior
is presented. The experimental information selected, main-
ly volumetric measurements, for the systems of interest
are collected in a form of a data bank collection. The pres-
ences of water and salts are also considered and salt sol-
ubility measurements of carbonates under carbon dioxide
atmosphere and in the presence of an organic solvent is
presented and discussed. Furthermore, this experimental
POSTERS 283
procedure is also described. Another observation for elec-
trolyte systems is the evidence of high temperature and
pressure vapor-liquid equilibrium data where the presence
of dissolved salts is found in the fluid phase similarly as
in the aqueous liquid phase. These evidences found in the
literature reinforce the complexity of the mixtures formed
in the pre-salt reservoir and demand of systematic research
and also in cooperation between several laboratories. This
cooperation is being feasible with the aid of the Human
Resources Programs sponsored by the National Agency
of Petroleum, Natural Gas and Biofuels and also by the
Petrobras University. In this research a work group has
been installed and has joined academic institutions cov-
ering the whole Brazil. These programs are forming stu-
dents in the undergraduate and graduate levels and they
are also critical mass to determine and calculate thermo-
dynamic and transport properties in study.
GREEN BIOREFINERy BASED ON SUPERCRITICAL CARBON DIOxIDE TEChNOLOGy FOR ThE PROCESSING OF DISTILLERS GRAINS
285
GREEN BIOREFINERy BASED ON SUPERCRITICAL CARBON DIOxIDE TEChNOLOGy FOR ThE PROCESSING OF DISTILLERS GRAINS
ozan nazim ciftci, feral TemelliUniversity of Alberta;
6020-118 Street South Campus AFDP, T6H2V8, Edmonton, Alberta, Canada;
E-mail: [email protected]
Even though supercritical carbon dioxide (scCO2) extrac-
tion has been accepted as a superior extraction method,
the general interest is still towards the extraction of low-
volume, high-value products. One way to widen the ap-
plication of scCO2 extraction is by taking full advantage of
the benefits of scCO2 processing, and this can be achieved
by scCO2 processing as part of a biorefinery. Development
of integrated supercritical processes for the green process-
ing of dried distillers grains with solubles (DDGS) using
the biorefinery concept to produce biodiesel, nutraceuti-
cals, and high-value food ingredients such as encapsulates
and delivery systems for bioactives as natural food ingre-
dients is the main focus of this research. DDGS is an in-
expensive byproduct of the ethanol industry. Currently,
DDGS is used as a livestock feed. However, its real value
is underestimated when its high lipid content and high
value minor lipid compounds such as phytosterols, tocols
and carotenoids are considered. Therefore, the objective
of this project is to add value to DDGS by the extraction of
lipids from DDGS with scCO2, fractionation of high-value
components such as tocols, phytosterols and carotenoids
from lipids of DDGS by scCO2, enzymatic conversion of
extracted DDGS lipids to fatty acid methyl esters (FAME,
286 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
biodiesel) in a novel continuous scCO2 bioreactor, and pro-
duction of micro- and nanoparticles using the minor lipid
and the protein fractions of the DDGS. DDGS was demon-
strated to be a good source of lipids and valuable minor
lipid components, which can be extracted using scCO2.
Developed biodiesel process based on lipase catalyzed
transesterification of triglycerides yielded FAME contents
of up to 95%, and has many advantages over convention-
al biodiesel process. It is simple, efficient and green. This
process can use a variety of feedstocks, low quality oils,
does not need catalyst removal, has fewer processing steps,
no wastewater is produced and immobilized enzyme can
be reused. No glycerol separation may be needed due to
the very low glycerol content of the product. Ongoing par-
ticle formation studies using the supercritical antisolvent
(SAS) process resulted in successful encapsulation of the
high value minor lipids with the zein fraction of the corn
DDGS residue obtained after lipid extraction. Encapsu-
lates as small as 100 nm were achieved using the SAS
process. scCO2-based biorefining of DDGS may be a prom-
ising way to add value to this byproduct; it may contribute
to the sustainability of the ethanol plants and may poten-
tially open a door for the scCO2 extraction of commodity
oils.
287
PhASE EqUILIBRIUM DATA OF MULTICOMPONENT SySTEMS FOR NANOENCAPSULATION PURPOSES
sibele R. Rosso comim, Thaís A. proença, natália Mezzomo, José vladimir de oliveira,
sandra R. s. ferreiraFederal University of Santa Catarina (UFSC), EQA/CTC; CP 476 – Trindade, 88040-900, Florianópolis, SC, Brazil;
E-mail: [email protected]
Carotenoids and ω-3 fatty acids are substances present
in the Pink shrimp (P. brasiliensis and P. paulensis) residue
with potential application as additives in the food indus-
try due to their nutritional importance, colorant potential,
antioxidant and hypolipidemic activities. On the other hand,
anthocyanis present in the grape pomace from Merlot
(Vitis vinifera) besides being antioxidants may offer anti-
inflammatory, anti-viral and anti-cancer benefits. However,
these substances are highly unstable. In order to preserve
the cited important biological activities, these extracts can
be encapsulated by high pressure techniques, such as SAS
(Supercritical Anti-Solvent process). The size control of
particles formed in the SAS process depends on the knowl-
edge of the equilibrium data of the involved compounds.
Best conditions for SAS experiments, where smaller par-
ticles are formed, are defined in the P-x phase equilibrium
diagrams as the single phase areas near the critical mix-
ture point (with high anti-solvent content). Therefore, this
work aimed to investigate the phase equilibrium behavior
of the multicomponent systems: shrimp residue extract +
acetone + carbon dioxide (CO2), pluronic + acetone + CO
2
and shrimp residue extract + pluronic + acetone + CO2 in
order to understand the changes in the acetone + CO2
288 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
phase equilibrium behavior with the addition of extract
and/or polymer and determine temperature, pressure and
composition for the encapsulation processes. The shrimp
residue extract was obtained by cold maceration with ac-
etone. The phase equilibrium data were acquired using
the synthetic static method. Phase equilibrium data for
grape pomace extract with ethyl acetate and PLGA in CO2
are also being collected. Phase equilibrium data was ob-
tained for CO2 mass contents from 49.93 to 98.05% at
temperatures of 308 K, 313 K, 318 K and 333 K. The systems
exhibited liquid-vapor equilibrium with transition pres-
sures up to 9.38 MPa and a lower critical solution tem-
perature behavior. The increase in temperature caused an
increase in transition pressures.
ThE PhASE EqUILIBRIUM DATA OF COMPLEx SySTEMS AND A PRESSURIzED LIqUID ExTRACTION STUDy OF BRAzILIAN GINSENG (pfAffiA gLoMERATA) ECDySTEROIDS
289
ThE PhASE EqUILIBRIUM DATA OF COMPLEx SySTEMS AND A PRESSURIzED LIqUID ExTRACTION STUDy OF BRAzILIAN GINSENG (pfAffiA gLoMERATA) ECDySTEROIDS
isabel c. n. Debien, M. Angela A. MeirelesLASEFI/DEA/FEA (School of Food Engineering),
UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil;
E-mail: [email protected]
This doctoral project is being developed in two steps, in-
cluding the measurement of phase equilibrium data of
complex systems [1,2] and a pressurized liquid extraction
study of Brazilian ginseng (Pfaffia glomerata) ecdysteroids.
STEP 1
Biodegradable polymers have received increased
attention in recent years due to their potential applications
in the medicine and food industries, with significant focus
given to poly (L-lactic acid) (PLA) mainly because of its
biocompatibility and resorptive features. The synthesis of
this biopolymer by the enzyme-catalyzed ring-opening
polymerization of L-lactic acid in compressed fluids has
been considered a promising route. The aim of this work
is to report the relevant phase equilibrium data (cloud
points) of L-lactic acid + (propane + ethanol) and L-lactic
acid + (carbon dioxide + ethanol). Phase equilibrium ex-
periments were conducted in a variable-volume view cell
employing the static synthetic method, varying tempera-
ture from 323.15 K to 353.15 K and at pressures up to 25
MPa. The mass ratio of ethanol to CO2 or propane was held
constant at 1:9. For the (propane + ethanol) + L-lactic
acid, the sequence of vapor-liquid, liquid-liquid and vapor-
290 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
liquid-liquid was observed, while for (carbon dioxide +
ethanol) + L-lactic acid, only the sequence of liquid-liquid
type transitions were recorded. The results show that the
system of (propane + ethanol) + L-lactic acid presents
UCST (Upper Critical Solution Temperature) transition type
and an UCEP, whereas the system of (carbon dioxide +
ethanol) + L-lactic acid exhibits LCST behavior.
STEP 2
Species of the genus Pfaffia are popular substi-
tutes for Panax due to their similarities in morphology and
bioactive properties. Among them, Pfaffia glomerata has
received particular attention due to the presence of ec-
dysteroids. Commercially, this compound is obtained us-
ing conventional solid-liquid extraction methods, that is,
by using large quantities of solvents. Today, more envi-
ronmentally friendly methods are preferred, such as pres-
surized liquid extraction (PLE), which enables the rapid
extraction of bioactive compounds under high temper-
atures. The aim of this step of the work is to study the
pressurized liquid extraction of Brazilian ginseng (Pfaffia
glomerata) ecdysteroids. The effects of temperature (333-
393 K), pressure (8-30 MPa) and solvent [ethanol and eth-
anol:water (80:20 v/v)] on the global yield of extraction,
antioxidant activity and β-ecdysone content of the extracts
from Brazilian ginseng (Pfaffia glomerata) roots were stud-
ied. The global yield of extraction increased with the in-
crease in temperature, while pressure did not affect the
extraction yield. When ethanol was used as the solvent,
the global yields varied from 1.5% at 333 K to 5.0% at 393
K. For the mixture of ethanol:water, the global yields var-
ied from 7.5% at 333 K to 25.1% at 393 K. As the tempera-
ture increased, the selectivity of the solvent decreased,
promoting the co-extraction of other compounds in addi-
POSTERS 291
tion to the ecdysteroids. This behavior may explain the
slightly higher antioxidant activities observed for the ex-
tracts obtained at 333 K in comparison to those obtained
at 363 and 393 K when using ethanol as the solvent; ad-
ditionally, the pressure did not affect the response variable.
A similar behavior was observed for the mixture of etha-
nol:water; however, at 333 K, the antioxidant activities
increased from 8 to 20 MPa and then decreased. Further,
ethanol was found to be more selective for the extraction
of the ecdysteroids, where fractions containing up to 5 % of
β-ecdysone were obtained using this solvent at 393 K. Thus,
the better extraction condition for β-ecdysone was select-
ed (393 K, 8 MPa and ethanol as the extracting solvent),
and a kinetic extraction study was performed. After two
hours of extraction (S/F approximately equal to 48), the
raw material was not exhausted. However, the β-ecdysone
content did not increase significantly after one hour of
extraction. After, the commercial software SuperPro De-
signer® will be used to evaluate the economic viability of
the process [3].
ACKNOWLEDGMENTS
The authors acknowledge the financial support from CAPES (PROCAD 244/2007 and DEA/FEA/PROEX); partial support from FAPESP (2012/10685-8) is also acknowledged. I. C. N. Debien thanks CNPq (CNPq 151165/2010-6) for the Ph.D. assistantship. M. A. A. Meireles thanks CNPq for the produc-tivity grant (302778/2007-1).
REFERENCES
[1] I. C. N. Debien, A. A. Rigo, M. A. Mazutti, J. V. Oliveira, M. A. A. Meireles, High-pressure phase equilibrium data for the L-lactic acid+(propane+ ethanol) and the L-lactic acid+(carbon dioxide+ethanol) systems, J. Supercritical Fluids, 79 (2013) 27-31.
[2] I. C. N. DEBIEN, A. A. RIGO, M. A. MAZUTTI, J. V. OLI VEIRA, M. A. A. MEIRELES. High-pressure phase equilibrium data for the systems L-latic acid + (Propane + Ethanol) and L-latic acid + (Carbon dioxide + Ethanol). In: 10th International Symposium on Supercritical Fluids, 2012, San Francisco, CA, USA.
292 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
[3] I. C. N. DEBIEN, R. VARDANEGA, D. T. SANTOS, M. A. A. MEIRELES.
Optimization of pressurized liquid extraction of ecdysteroids from Bra-
zilian ginseng roots. In: III Iberoamerican Conference on Supercritical
Fluids, 2013, Cartagena das Indias.
UPDATING TRADITIONAL MEDICINE: NATURAL-BASED MEDICATED BIOMATERIALS FOR wOUND DRESSING APPLICATIONS USING GREENER PROCESSES
293
UPDATING TRADITIONAL MEDICINE: NATURAL-BASED MEDICATED BIOMATERIALS FOR wOUND DRESSING APPLICATIONS USING GREENER PROCESSES
Ana M. A. Dias, Mara E. M. Braga, hermínio c. de sousa
CIEPQPF – Chemical Engineering Departament, FCTUC, University of Coimbra;
Rua Silvio Lima, s/nº, Pólo II, Pinhal de Marrocos, 3030-790, Coimbra, Portugal;
E-mails: [email protected]; [email protected], [email protected]
Phytochemicals are biologically active chemical com-
pounds, naturally occurring in plants, where they act as
a natural defense system. They can be broadly classified
into major (g/100 g of plant material) and minor (microgram
to milligram range/100 g of plant material) constituents.
Major constituents include carbohydrates, lipids and pro-
teins while minor constituents include vitamins, minerals
and health beneficial secondary metabolites (phenolics,
terpenes, carotenoids, alkaloids, saponins, vitamins, pre-
and probiotics, bioactive peptides, etc). These metabolites
often present antioxidant, antimicrobial, anesthetic/stim-
ulant, anti-inflammatory, anticancer or antimalarial thera-
peutic capacities (among others), which justifies the wider
and common use of plants as medication tool in tradition-
al and complementary medicine worldwide. The World
Health Organization (WHO) supports traditional medicine
provided it proves to be efficacious and safe. According to
WHO reports, traditional medicines are estimated to be
used by 60% of the world’s population and in some coun-
tries are extensively incorporated into the public health
system. Some major categories of plant-derived products
include phyto-pharmaceuticals, herbal medicines, natural
294 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
health products, phyto-cosmetics and personal care prod-
ucts. The global demand for these products is increasing
due to a renewed interest of consumers for natural-based
products, since they are considered safer and more cost-
effective when compared to synthetic counterparts. Wound
healing is a specific health care area in which many plant-
derived products have been applied since ancient times
and this empirical knowledge still persists nowadays. Mod-
ern wound dressings are developed taking into consider-
ation three essential factors: that the dressing is able to
provide proper physiologic wound environment, to act as
a barrier for microorganisms and to stimulate healing. The
later can be enhanced by the impregnation of the dressing
with active substances like antibiotics, antimicrobial and/
or antiseptic agents to enhance the body’s own healing
mechanism. Over the last years our group has been working
on the development of medicated wound dressing mate-
rials using generally regarded as safe (GRAS) materials,
solvents and techniques. Our aim is to develop biocom-
patible and/or biodegradable biomaterials loaded with nat-
ural based bioactive compounds and using supercritical
fluid technologies (extraction and impregnation/deposi-
tion). These technologies are accepted as valuable alter-
natives to develop specialized materials for biomedical
applications, for which restrictive toxicity/biocompatibil-
ity limits have to be accomplished. Biomaterials tested so
far include agarose, chitosan (and several derivatives) and
mesoporous nanostructured silica while different natural-
based bioactive and/or plant extracts have been screened
for their antioxidant, anti-inflammatory and/or analgesic
bioactivity. These bioactive compounds include pure sub-
stance (such as quercetin, thymol and naphtoquinones)
and lipophilic extracts of jucá (Caesalpinia ferrea) or jambu
(Spilanthes acmella var oleracea) which are used in folk
POSTERS 295
medicine as natural anti-inflammatory and analgesic wound
healing agents, respectively. This work will present and
discuss the main results obtained so far and which include
natural extracts characterization, solubility of natural based
compounds in scCO2 and physical-chemical-biological
characterization of scCO2 loaded biomaterials according
to standard methodologies that permit to select those that
can be used as wound dressings (in terms of required po-
rosity, fluid handling capacity, hydrophilicity, cytotoxicity,
sustained release capacity and resilience).
ThE USE OF BIOREFINERy IN ThE AGRICULTURAL AND FOOD INDUSTRIES: hyDROLySIS AND GASIFICATION FOR BIO-hyDROGEN
297
ThE USE OF BIOREFINERy IN ThE AGRICULTURAL AND FOOD INDUSTRIES: hyDROLySIS AND GASIFICATION FOR BIO-hyDROGEN
Tania forster-carneiro, cristiana B. carneiro, M. Angela A. Meireles
LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas);
R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]
Juliana M. pradoCTBE (Brazilian Bioethanol Science and Technology Laboratory),
CNPEM (Integrate Brazilian Center of Research in Energy and Materials); R. Giuseppe Máximo Scolfaro, 10.000, 13083-970, Campinas, SP, Brazil
Mauro BerniNIPE-Interdisciplinary Centre of Energy Planning,
University of Campinas (UNICAMP), SP, Brazil
A biorefinery is an industrial plant that fully utilizes raw
materials, sustainably, for the concomitant production of
food by-products with high added value and biofuels/en-
ergy. The organic residue recycling technologies used to
produce new products with energy recovery are emerging
as efficient and economically viable alternatives with sig-
nificant potential in terms of production and market value.
Brazil is recognized as a world leader in the export of food;
however, the industrial activities of the agri-food sector
generate significant amounts of organic waste. These res-
idues could become a major renewable resource for the
production of new chemicals, fuels and energy. There is
significant debate today regarding the environmentally
sound disposal of organic waste because, according to the
law n. 12.305 of 2010, such waste can no longer be final-
ly disposed in landfills. Sub/supercritical hydrolysis and
gasification are among these emerging technologies. Re-
298 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
cent research indicates that supercritical fluid technology
is economically viable when compared with thermal gas-
ification due to the high solubility of the biomass compo-
nents in supercritical water, which generates a cleaner gas
(no tar and pitch), as well as the highest concentration of
bio-hydrogen. The challenge of this technology is the op-
timization of the operating parameters involved in the pro-
cess to maximize the effects of temperature and pressure.
The use of gasification technology with supercritical wa-
ter presents significant advantages in comparison with
the thermal gasification processes already utilized in dry-
ing steps. With respect to gas production, recent studies
have shown that the primary gases produced during gas-
ification with supercritical water differ significantly from
the thermal gasification process: the gas produced is clean
(no tar), the hydrogen content is higher, dilution by nitro-
gen (N2) is not observed and the concentrations of carbon
monoxide (CO) and methane (CH4) are highly dependent
on the operational conditions. The complete conversion
of carbon is achieved after a relatively short residence
time, and significant amounts of CO are found in com-
parison with the low methane concentration. Further, bio-
hydrogen is produced directly at high pressures, which
means smaller reactor volumes and lower energy for pres-
surizing the gas in a storage tank are necessary. Currently,
the production of biogas is exploited industrially by fer-
mentation technology (biological treatment), and methane
gas is one of the vectors of renewable energy. However,
hydrogen gas (H2) is a clean gas and can be recycled. The
use of hydrogen incorporates technology that eliminates
the need for the deployment of new transmission lines,
because the conversion of electrical or thermal energy can
be performed on-site using the potential energy in small
spaces. The challenge of this work is the associated bio-
POSTERS 299
hydrogen production at lower temperatures (subcritical
conditions, 200-374 ºC). It is expected that the operating con-
ditions of the hydrolysis step, followed by gasification in
subcritical water, favor the production of bio-hydrogen;
the residence time is low due to the high solubility of the
components of cellulose biomass. The use of lower tem-
peratures represents a significant advantage, contributing
to reductions of investment and operating costs, as well
as maintenance. In this project, a new line of research is
proposed to develop new products with high value-added
technologies based on hydrolysis and gasification with
subcritical/supercritical water. Extensive tests (bio-hydrogen
and methane) with different operating parameters will be
needed, as well as the determination of gas composition
and assessments of the performance of different waste
types (soy, sugarcane, peanuts, palm fiber, coconut fiber,
grape seed and tomatoes wastes). This project proposes
the production of a clean gas with a high bio-hydrogen
concentration at lower temperatures (subcritical condi-
tions, 200-374 ºC), seeking to reduce the production costs
of sub/supercritical gasification at large scales. The assays
are performed in LASEFI/UNICAMP, which has adequate
infrastructure to achieve the proposed objectives of this
project. Specifically, the location possesses several units
for extraction and supercritical hydrolysis, most of which
were designed and tested in the laboratory, and can be
used with modifications to its configuration. The experi-
ments were performed in a semi-batch unit equipped with
a 50-ml reaction vessel was used for the SWH of raw ma-
terials (bagasse sugarcane, defatted grape seeds, pressed
palm fiber and coconut husk). Each sample was inserted
into the reactor, which was connected to the equipment,
and the experiments were carried out using 10-35 g of raw
material. Distilled water was pumped through the system
300 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
to remove residual air, and once the system was filled with
water, the pump was stopped, and the micrometric valve
was closed. The coil was heated, and the reactor was start-
ed. The heating coil temperature was set at the processing
temperature while the reactor was pre-heated to 120 ºC.
The temperature stabilized at approximately 20 min after
start, and the dynamic period of the process was started
by pumping water at 33 mL/min through the system for
30 min. When the dynamic period was initiated, the reac-
tor temperature was set to the processing temperature
(200 ºC or 250 ºC), leading to the development of a tempera-
ture profile over time until the temperature had stabilized.
The pressure was held constant at 20 MPa. Hydrolysate
samples were collected every 2 min. All experiments were
performed in duplicate. The hydrolysates were analyzed
by HPLC for their contents of 5-hydroxymethylfurfural (5-
HMF) and carbon-6 and carbon-5 (arabinose, fructose,
galactose, glucose, mannose, xylose, cellobiose and raffi-
nose). The preliminary results indicate that higher concen-
trations of sugars were obtained from sugarcane bagasse,
followed by fibrate coconut palm fiber and grape seeds.
The total sugars yielded and the liquefaction degree also
were obtained.
A STUDy OF ThE PARTICLE FORMATION OF ANNATTO ExTRACT USING SUPERCRITICAL FLUID TEChNOLOGy
301
A STUDy OF ThE PARTICLE FORMATION OF ANNATTO ExTRACT USING SUPERCRITICAL FLUID TEChNOLOGy
M. Thereza M. s. gomes, Diego T. santos*, M. Angela A. Meireles
LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas);
R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]
*Industrial Energy Systems Laboratory (LENI), Swiss Federal Institute of Technology Lausanne (EPFL);
Station 9, CH-1015, Lausanne, Switzerland
Particle design using supercritical CO2 has received sig-
nificant interest over the past 20 years. Supercritical fluids
have been used as solvents, solutes, and antisolvents for
micro- and nanoparticle formation in a variety of com-
pounds and have overcome all of the limitations of tra-
ditional techniques. In an effort to increase the value of
extracts from annatto seeds, this study aims to coprecip-
itate annatto extract and polyethylene glycol (PEG) using
antisolvent processes, resulting in higher bioavailability
and enabling the protection of the unstable compounds
with respect to adverse conditions. The main pigments of
annatto seeds are bixin and norbixin, which are valuable
natural colorants. However, these seeds have acquired no-
toriety because they contain other important substances
for human health, such as tocopherols, tocotrienols and
geranylgeraniol. Due to the importance of these bioactive
compounds, for which recent studies have demonstrated
the protective effects of tocotrienols against neurodegen-
erative diseases, atherosclerosis and cancer, as well as their
antioxidant properties, obtaining these compounds was
the goal of this study. Thus, to add value to the δ-tocotrienol-
302 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
rich extracts obtained from annatto seeds using supercrit-
ical fluid extraction (SFE), we proposed the coprecipitation
of the annatto seed extract and a polymer using SAS
(Supercritical Antisolvent) and SFEE (Supercritical Fluid
Extrac tion of Emulsions) processes. First, a homemade
experimental apparatus was constructed by our research
group, and the apparatus was validated using a model
substance (Ibuprofen sodium salt). The effects of various
operating conditions (temperature, pressure, CO2 flow rate,
solution flow rate, injector type and concentration of ibu-
profen sodium in the ethanol solution) on the precipitation
yield, the energy consumption per unit of manufactured
product, the residual solvent content and particle mor-
phology were investigated using split-plot designs. Ibu-
profen sodium salt was successfully micronized by the SAS
process using the constructed unit. Then, SAS and SFEE
processes were applied to the ternary system of polyeth-
ylene glycol (PEG) + dichloromethane + annatto seed
extract to obtain dry coprecipitates and nanosuspensions,
respectively. The particle size, precipitation yield, residual
solvent content and morphology of the product as func-
tions of pressure, temperature, solution to antisolvent flow
rate and extract to PEG mass ratios are evaluated.
ACKNOWLEDGMENTS
The authors acknowledge the financial support from CNPq (564721-2010-7).
M. T. M. S. Gomes thanks CNPq (140641/2011-4) for the Ph.D. assistantship.
GREEN SOLVENTS FOR PRECISION CLEANING
303
GREEN SOLVENTS FOR PRECISION CLEANING
heather E. grandelli, phillip Maloney, Robert Devor, Jan surma, paul E. hintze
National Aeronautics and Space Administration; 870 Claytor Square, 24060 Blacksburg, VA, USA;
E-mail: [email protected]
Aerospace machinery used in liquid oxygen (LOX) fuel
systems must be precision cleaned to achieve a very low
level of non-volatile residue (< 1 mg/0.1 m2), especially
flammable residue. Traditionally chlorofluorocarbons (CFCs)
have been used in the precision cleaning of LOX systems,
specifically CFC 113 (C2Cl
3F
3). CFCs have been known to
cause the depletion of ozone and in 1987 were banned by
the Montreal Protocol due to health, safety and environ-
mental concerns. This has now led to the development of
new processes in the precision cleaning of aerospace com-
ponents. An ideal solvent-replacement is non-flammable,
environmentally benign, non-corrosive, inexpensive, effec-
tive and evaporates completely, leaving no residue. High-
lighted is a ‘green’ precision cleaning process, which is
contaminant removal using supercritical carbon dioxide
as the environmentally benign solvent. In this process, the
contaminant is dissolved in carbon dioxide, and the parts
are recovered at the end of the cleaning process complete-
ly dry and ready for use. Typical contaminants of aerospace
components include hydrocarbon greases, hydraulic flu-
ids, silicone fluids and greases, fluorocarbon fluids and
greases and fingerprint oil. Metallic aerospace components
range from small nuts and bolts to much larger parts, such
304 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
as butterfly valves 18” in diameter. A fluorinated grease,
Krytox®, is investigated as a model contaminant in these
preliminary studies, and aluminum coupons are employed
as a model aerospace component. Preliminary studies are
presented in which the experimental parameters are op-
timized for removal of Krytox® from aluminum coupons
in a stirred-batch process. The experimental conditions
investigated are temperature, pressure, exposure time and
impeller speed. Temperatures of 308-423 K, pressures in
the range of 8.3-41.4 MPa, exposure times between 5-60
min and impeller speeds of 0-1000 rpm were investigated.
Preliminary results showed up to 86% cleaning efficiency
with the moderate processing conditions of 323 K, 13.8 MPa,
30 min and 750 rpm.
LIGNITE GASIFICATION IN SUPERCRITICAL WATER: KINETICS AND NUMERICAL STUDy (REVISED)
305
LIGNITE GASIFICATION IN SUPERCRITICAL WATER: KINETICS AND NUMERICAL STUDy (REVISED)
simao guo, Liejin guo, hui Jin, Zhiwei ge, youjun LuState Key Lab of Multiphase Flow in Power Engineering (SKLMF),
Xi’an Jiaotong University (XJTU);Xianning West Road 28# Xi’an, Sha’anxi, 710049, The People’s Republic of China;
E-mail: [email protected]
Supercritical water gasification (SCWG) is a clean and ef-
ficient technology to convert lignite to hydrogen rich gas.
In order to know the quantitative rule of the lignite gasifi-
cation in supercritical water (SCW), this work proposed a
simplified reaction pathway for lignite gasification in SCW,
and developed a quantitative kinetics model for describing
production gases (H2, CO, CH
4, CO
2) yields. The kinetics
model contained seven typical reactions (pyrolysis, lique-
faction, steam reforming, methanation, water-gas shift
reaction) occurred in supercritical water gasification in-
cluding both homogeneous and heterogeneous reactions.
Apparent activation energy and frequency factor of each
reaction were obtained by fitting the experiments data
(5~25 wt% lignite slurry, 650~850 ºC, 13~120 s residence
time) using nonlinear least-square fitting method improved
by genetic algorithm. Then, the kinetics model was ap-
plied in a three-dimensional computational fluid dynam-
ics (CFD) model of a SCW fluidized bed reactor developed
by the State Key Laboratory of Multiphase Flow in Power
Engineering (SKLMF). The CFD model was established
for better understanding the complex physical and chem-
ical reaction phenomena of SCWG of lignite in the reactor,
and providing information for better reactor design /scale
306 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
up. By comparing the simulated results with experimental
data, the CFD model was validated. Based on the CFD
model, some valuable information such as the detailed
flow field, temperature distribution, chemical component
distribution and particles residence time distribution in-
side the reactor were obtained. The bottlenecks of com-
pletely gasification of lignite were pointed out. The effects
of the reactor wall temperature, preheated water tempera-
ture, lignite particle size and alkali catalysts on SCWG of
lignite were numerical investigated by the CFD model.
Moreover, several types of new reactor designs were eval-
uated by the CFD model, and the optimal design was pro-
posed for further SCW fluidized bed reactor development.
Finally, a comprehensive solution including both a new
designed reactor and its operating parameters for com-
pletely gasification of lignite in a moderate reaction tem-
perature condition was proposed. All these researches are
not only helpful to develop the technology of SCWG of
lignite, but also have theoretical values in other organics
(e.g. biomass, waste organics) gasification in SCW.
Key words: Supercritical Water Gasification (SCWG);
Lignite, Kinetics, Fluidized Bed Reactor; Numerical Study.
SUPERCRITICAL FLUID ExTRACTION FROM NATURAL PRODUCTS: AN OVERVIEW OF ThE MAThEMATICAL MODELING, SCALE-UP, SIMULATION AND ECONOMIC ANALySIS OF ThE PROCESS
307
SUPERCRITICAL FLUID ExTRACTION FROM NATURAL PRODUCTS: AN OVERVIEW OF ThE MAThEMATICAL MODELING, SCALE-UP, SIMULATION AND ECONOMIC ANALySIS OF ThE PROCESS
susana p. Jesus, M. Angela A. MeirelesLASEFI/DEA/FEA (School of Food Engineering),
UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil;
E-mail: [email protected]
Supercritical Fluid Extraction (SFE) is a high-pressure ex-
traction technique in which the solvent is a fluid (usually
carbon dioxide) in the supercritical state. It is a green tech-
nology that has been extensively studied in more than
three decades of intensive research. As a result, a solid
knowledge base of the fundamentals of SFE has already
been established, and significant amounts of experimen-
tal data are available in the scientific literature. The SFE
process has been applied on the commercial scale since
the 1980s [1]. Further, a wide number of industrial plants
of various capacities have been built during recent de-
cades. These operating plants are mostly distributed in
Europe, the USA, Japan, and in the South East Asian Coun-
tries [2]. However, in Brazil and many other countries, SFE
processes are not yet carried out on the commercial scale.
Therefore, SFE can still be considered an emerging tech-
nology because the conventional methods are the most
commonly used approaches in various applications of sol-
id-fluid extraction. In particular, this fact is the result of
the requirements of high-pressure processes, which ne-
cessitate higher investment costs in comparison to low-
pressure plants. Nonetheless, it is well known that several
308 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
other costs (in addition to investment costs) also must be
considered when estimating the cost of manufacturing
(COM) of some desired products [3].
Today, one of the crucial challenges in SFE inves-
tigation is to show that this process can be commercially
competitive in a variety of situations. Accordingly, special
attention must be given to the information that is required
for preliminary studies of process design and cost estima-
tion. The main goal of this work is to evaluate the calcu-
lation procedures used to obtain process design data that
may be applied in preliminary studies of economic feasi-
bility. For this purpose, some experimental data (available
from previous works performed by our research group) are
being used to investigate the mathematical modeling,
scale-up, simulation and economic analysis of the SFE
process.
First, the mathematical modeling of the overall ex-
traction curve (OEC) was studied, with focus on the ap-
plication of low-complexity models. The spline model, as
presented by Meireles [4], was successfully applied to
describe the kinetic data of SFE from rice bran oil soap-
stock. The results obtained are detailed in the recently
published work by Jesus et al. [5]. Second, a more complete
evaluation of the mathematical modeling of the OEC was
performed using the kinetic data from five different raw
materials (clove, ginger, grape seed, sugarcane residue,
and lemon verbena). The main purpose was to carry out
a comparison between the spline model [4] and the mod-
el developed by Sovová [6]. These models were evaluated
by considering the fitting performance (mean square error
and distribution of the residuals) and the applicability of
the adjusted parameters in terms of providing useful in-
formation for process design. A subsequent part of this
work will comprise some aspects of scale-up, simulation,
POSTERS 309
and cost analysis. Estimations of large-scale data will be
performed according to the scale-up criterion proposed by
Prado et al. [7] in a previous work from our research group.
The simulation of the SFE process on an industrial scale
and the economic analysis will be performed using the
commercial software SuperPro Designer® (Intelligen, Inc.,
USA).
ACKNOWLEDGEMENTS
The authors acknowledge the financial support from CAPES (DEA/FEA/
PROEX). S. P. Jesus thanks CNPq (141828/2010-2) for the Ph.D. assistantship.
M. A. A. Meireles thanks CNPq for the productivity grant (302778/2007-1).
REFERENCES
[1] G. Brunner, Gas extraction: An Introduction to Fundamentals of Su-
percritical Fluids and the Application to Separation Process. 1. ed.,
Steinkopff; Darmstadt; 1994. 387 p.
[2] G. Brunner, Supercritical fluids: technology and application to food
processing, J. Food Engineering, 67 (2005) 21-33.
[3] P. T. V., Rosa, M. A. M. Meireles, Rapid estimation of the manufactur-
ing cost of extracts obtained by supercritical fluid extraction, J. Food
Engineering, 67 (2005) 235-240.
[4] M. A. A. Meireles, Extraction of bioactive compounds from Latin Amer-
ican plants. In: J. Martinez (Org.). Supercritical fluid extraction of nu-
traceuticals and bioactive compounds, Boca Raton: CRC Press – Taylor
and Francis Group, 2008, 243-274.
[5] S. P. Jesus, M. N. Calheiros, H. Hense, M. A. A. Meireles, A Simplified
Model to Describe the Kinetic Behavior of Supercritical Fluid Extraction
from a Rice Bran Oil Byproduct, Food and Public Health, 4(3) (2013)
215-222.
[6] H. Sovová, Rate of the Vegetable Oil Extraction with Supercritical CO2:
I. Modeling of Extraction Curves, Chemical Engineering Science, 3(49)
(1994) 409-414.
[7] J. M. Prado, G. H. C. Prado, M. A. A. Meireles, Scale-up study of su-
percritical fluid extraction process for clove and sugarcane residue, J.
Supercritical Fluids, 56 (2011) 231-237.
STUDy ON FURFURAL GASIFICATION ChARACTERISTICS IN SUPERCRITICAL WATER AND ITS REACTION PAThWAy
311
STUDy ON FURFURAL GASIFICATION ChARACTERISTICS IN SUPERCRITICAL WATER AND ITS REACTION PAThWAy
hui JinState Key Lab of Multiphase Flow in Power Engineering (SKLMF),
Xi’an Jiaotong University (XJTU);Xianning West Road 28# Xi’an, Sha’anxi, 710049, The People’s Republic of China;
E-mail: [email protected]
Liquid fuel such as alkane and oxygenated fuel can be
produced from biomass depolymerization product, and the
process hydrogen is consumed. At the same time, a great
amount of by-products wastes production is inevitable, so
hydrogen production by supercritical water gasification
from the by-products wastes production makes this tech-
nology have more independence and better economy. How-
ever, publication about hydrogen production by supercritical
water gasification from by-products wastes from biomass
depolymerization is quite limited and the key hurdle pre-
vent furfural from complete gasification of the wastes is
still unknown and the optimal operational parameters. A
high throughput (6 channels) gasification apparatus is
established in State Key Laboratory of Multiphase Flow
in Power Engineering (SKLMF) for the supercritical water
gasification and furfural is selected as a model compound.
Temperature range of 400 ºC~700 ºC, pressure range of
25 MPa~40 MPa, reactor residence time of 0 minute ~ 20
minute, concentration of 2 wt% ~ 30 wt% were selected
for the exploration of the complete gasification condition.
The quantitative and qualitative analysis of the gaseous
products are operated by Gas chromatography/Mass spec-
tra and wet type gas meter. The main compounds of the
312 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
liquid products are analyzed by Gas chromatography/Mass
spectra and total organic carbon. The solid residual is an-
alyzed by scanning electron microscope and Fourier trans-
form infrared spectroscopy and Industrial analysis and
elemental analysis. A thermodynamics model based on
the Gibbs free minimization energy was proposed to show
the chemical reaction limit and to predict the products dis-
tributions. Equation of state of the mixing rule by Duan is
adopted. It is predicted that furfural can be gasi fied com-
pletely in supercritical water and the main gaseous prod-
ucts are hydrogen and carbon dioxide. A reaction kinetics
analysis is conducted to make clear the influence of the
key reaction path with the operating condition. It can be
concluded that the main intermediates are cyclopenta-
none, propionic acid and phenols. The research results
supplies the possibility of providing the optimal reaction
condition for the main reaction of furfural gasification in
supercritical water, retaining the side reaction and realiz-
ing the orientation gasification of furfural in supercritical
water.
TWO-PhASE FLOW ChARACTERISTICS IN SUPERCRITICAL wATER FLUIDIzED BED
313
TWO-PhASE FLOW ChARACTERISTICS IN SUPERCRITICAL wATER FLUIDIzED BED
youjun Lu, pengfei Zheng, Liping WeiState Key Lab of Multiphase Flow in Power Engineering (SKLMF),
Xi’an Jiaotong University (XJTU); Xianning West Road 28# Xi’an, Sha’anxi, 710049, The People’s Republic of China;
E-mail: [email protected]
Supercritical water fluidized bed is a new reactor concept
for biomass gasification. Two-phase flow characteristics
in supercritical water fluidized bed have a significant effect
on the heat and mass transfer, contact between particle
and fluid, and chemical reaction. Firstly, an experimental
study on the hydrodynamics of a supercritical water flu-
idized bed was conducted. The frictional pressure drops
of a fixed bed and a fluidized bed were measured for a
temperature ranging from 633 to 693 K and pressure rang-
ing from 23 to 27 MPa. The results show that the Ergun
formula for calculating the frictional pressure drop of a
fixed bed can still be applied in supercritical water con-
ditions. The average deviation between Ergun formula and
experiment results is 13.3%. A predicting correlation for
the minimum fluidization velocity in a supercritical water
fluidized bed was obtained based on the experimental re-
sults of a fixed bed and the fluidized bed pressure drop.
The average error between the correlation and experiment
results was about 3.1%. However, experimental study is
still very difficult because of its severe operating condi-
tions in the SCW fluidized bed. Therefore, the two-phase
flow characteristics in the supercritical water fluidized bed
have been studied with Discrete Element Method, in order
314 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
to provide theoretical basis for design and structure opti-
mization of a supercritical fluidized bed reactor. The drag
model provided by Wen & Yu (1966), Gidaspow (1987), and
Syamlal & O’Brien (1989) were evaluated through mod-
eling the bed expansion, solid particle velocity, and bed
pressure drop, and minimum fluidization velocities of SCW
fluidized bed. In simulation, the density and viscosity of
SCW fluid were 283.79 kg/m3 and 3.67×10-5 Pa∙s, and the
density and diameter of particles were 2580 kg/m3 and
0.5 mm. Based on the simulation results, both Gidsapow
and Syamlal & O’Brien drag models predicate similar bed
expansion height, pressure drop, and particle velocities
distribution. Comparing to Gidsapow drag model and
Syamlal & O’Brien drag model, Wen & Yu drag model pred-
icates higher bed expansion height and higher pressure
drop when u/umf<1.2, but lower bed expansion height
when u/umf 1.2. The deviation of minimum fluidization
velocity between simulations and experimental results
were with 2.85% for Gidsapow drag model and Syamlal &
O’Brien drag model, but 8.75% for Wen & Yu drag model.
Therefore, it is suitable to simulate SCW fluidized bed by
using Gidsapow drag model or Syamlal & O’Brien drag
model. The huge divergences of two-phase flow character-
istics in SCW fluidized bed and in gas-solid fluidized bed
can be found by comparisons of bed pressure drop, average
particle height and bubble characteristics. The density and
viscosity of gas used in present study are 0.33 kg/m3,
and 2.38×10-5 Pa∙s. When superficial velocity was above
the minimum fluidization velocity, the amplitude of pres-
sure drop of gas-solid fluidized bed is greater than that of
SCW fluidized bed. The bed pressure drop power spectrum
analysis shows that the dominant frequency is 2.8 Hz for
SCW fluidized bed, but 3.2 Hz for gas-solid fluidized bed,
which indicates a stronger bubble collision ratio, coales-
POSTERS 315
cence, and break open in gas-solid fluidized bed. The
number and size of bubbles in gas-solid fluidized bed is
greater than that in SCW fluidized bed at the same bed
height level. Also, the effect of superficial velocity, tem-
perature and pressure on bubble amount, bubble size and
bubble velocity is revealed respectively in SCW fluidized
bed. The results in this paper are useful for the design of
SCW fluidized bed.
SUPERCRITICAL DESORPTION OF CAROTENES FROM ALUMINA ADSORBENTS
317
SUPERCRITICAL DESORPTION OF CAROTENES FROM ALUMINA ADSORBENTS
M. A. E. cunha, A. L. santana, c. f. M. Batista, f. f. M. Azevedo, M. E. Araújo, n. T. Machado
Laboratory of Separation Processes and Applied Thermodynamic, Faculty of Chemical Engineering (UFPA);
Rua Augusto Corrêa, 1, 66075-900, Belém, Pará, Brazil; E-mail: [email protected]
Buriti (Mauritia flexuosa, Mart), a native palm growing in
swamps and flooded areas along rivers and forests on the
Amazon region, is one of the palms with the highest eco-
nomic potential because its oil is a rich natural source of
pro-vitamin A. The fruits of Buriti have a soft and oily
dark-yellow to reddish pulp, containing between 20-30%
(wt.) of a reddish oil with the highest concentration of
carotenes in vegetable oils, with an estimate annual av-
erage oil specific production of 57.5 ± 17.0 kg.ha-1, having
a great economic potential of application in the food and
cosmetic industries because of its effectiveness on the
treatment and prevention of diseases caused by deficien-
cy in vitamin A, use as natural plasticizer for starch, ab-
sorption and photoluminescence optical properties, low
cytotoxicity in creams and lotions formulations, and pho-
toprotective properties against UVA and UVB irradiation
on cells. Since the pioneer work of Model et al., supercrit-
ical carbon dioxide has been applied on desorption of syn-
thetic chemicals (e.g. phenol, ethyl acetate, benzene, toluene,
naphthalene, phenanthrene, hexachlorobenzene, penta-
chlorophenol, and isomeric dimethylnaphthalene mixtures,
DDT, n-hexane, methyl ethyl ketone, and toluene, ethyl
acetate and furfural, m-xylene, benzoic acid or salicylic
318 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
acid), essential oils (e.g. lemon, bergamot, mandarin, lime
and bitter orange oil), and even fat-soluble substances from
vegetable oils (carotenes, β-carotenes, tocopherol acetate,
α-tocopherol), loaded in different adsorbents (e.g. silica
gel, aluminum oxides, γ-alumina, activated carbon, cellu-
lose, bentonite, magnesium silicate, and zeolite), as report-
ed in the literature. Despite the development of several
processes to recover and concentrate carotenes from veg-
etable oils by traditional methods, particularly crude palm
oil, degummed palm oil, palm fatty distillates and refined,
bleached and deodorizer palm oil reported in the literature,
only a few works have been reported concerning the ap-
plication of supercritical adsorption/desorption processes
to recover and/or enrich carotenes from vegetable oils, in-
cluding batch adsorption of crude palm oil in stirred tanks
followed by supercritical desorption, supercritical adsorp-
tion of Buriti oil (Mauritia flexuosa, Mart) related com-
pounds in γ-alumina adsorbent using carbon dioxide. In
this work, enriching of carotenes has been systematically
investigated by supercritical desorption process. The de-
sorption of carotenes from preparative columns packed
with γ-alumina adsorbents loaded with Buriti oil has been
determined experimentally at 20 and 25 MPa, 333 K, and
solvent flow rate of QCO2 = 10.6 l/min, using a high pres-
sure apparatus with a jacket autoclave (Mechanical Work-
shop, TUHH-Germany) of 1000 cm³, adapted to be used as
a desorption cell by assembling 01 (one) cylinder of 2.7 cm
internal diameter and 14.25 cm height inside the high
pressure vessel of 1000 cm³, a diaphragm-type compressor
(Andreas Hofer Hochdrucktechnik GmbH, Model: MKZ
120-50), a sampling system with a separator of 130 cm³
(Mechanical Workshop, UFPA-Brazil), a thermostatic bath
(Haake Mess-Technik GmbH, Model N3), a carbon dioxide
reservoir and a gas meter. Buriti oil has been characterized
POSTERS 319
according to the following AOCS official methods: AOCS
Cd 3d-63, AOCS Cd 3-25, AOCS Cd 8b-90, AOCS Cd-1.25,
and AOCS 940.28 [42], Refraction Index by adjusting the
Abbé Refractometer with distilled water (IR 20 ºC = 1.333),
density at 313 K, viscosity according to ASTM 446 and
ASTM D 2515 methods using a Cannon-Fenske viscosim-
eter, (Capillary tube Nº. 200) and carotenes by UV-VIS
spectrophotometry and HPLC. The fixed bed containing
γ-alumina loaded with Buriti oil has been characterized
in terms of height (m), internal diameter (m), adsorbent
equilibrium capacity (g/kg), particle diameter (A), particle
porosity (-), fixed bed porosity (-), CO2 interstitial velocity
(m/s), and adsorbent density (kg/m³). The mass transfer
models of Tan and Liou and Brady et.al have been applied
to describe the kinetic behavior of supercritical desorption
process. The influence of pressure and adsorbent capacity
on the supercritical desorption processes has been inves-
tigated by analyzing the mass transfer performance. The
solubility of Buriti oil in supercritical carbon dioxide has
been computed by linear adjust of desorption kinetic by
determining the final point of the linear part of desorption/
extraction curve. A computational algorithm code written
in EXCEL using the build in function PROJ.LIN has been
used to calculate the period of constant extraction rate,
the mass transfer rate for the period of constant extraction
rate and the solubility. This spreadsheet calculator gen-
erates a graphic that shows automatically the splines of
both straight lines describing the periods of constant and
decreasing extraction rate being adjusted. A 2.5 fold en-
riching of carotenes has been obtained by integrated su-
percritical adsorption/desorption of Buriti oil fat soluble
compounds in γ-alumina adsorbent using carbon dioxide
as solvent, posing this methodology as an alternative meth-
od for the enrichment of carotenes from vegetable oils.
CARBON DIOxIDE CAPTURE AND UTILISATION FOR ENERGy GENERATION AND COMPOSITE MATERIALS
321
CARBON DIOxIDE CAPTURE AND UTILISATION FOR ENERGy GENERATION AND COMPOSITE MATERIALS
fabricio c. Marques, neil Rowson, peter J. hammond, Regina c. D. santos
University of Birmingham;Edgbaston, B15 2TT, Birmingham, West Midlands, UK;
E-mail: [email protected]
There is growing agreement that anthropogenic emission
of greenhouse gases like carbon dioxide (CO2) have led to
global warming and climate change on a global scale,
which are having dire consequences for the Earth’s eco-
system. Fortunately there are many technologies that can
capture CO2. Nevertheless, most processes propose storing
it underground, which requires a very large infrastructure
that is costly and energy-intensive, not to mention other
negative impacts on the environment. In addition large
quantities of CO2 can be released back to the atmosphere
if naturally-occurring phenomena or accidents occur. As
a result, a novel process has been developed in conjunc-
tion with industrial partner CCm Research Ltd., where
eco-friendly cellulosic-based biomass is functionalised
with amine compounds that effectively chemisorb CO2 in
an exothermic reaction and convert it to a stable carbon-
ate form (R-CO3). The carbonate structure has been con-
firmed with FTIR and SEM, and the reaction mechanism
and thermal stability of the material have been studied
with a simultaneous thermal analyser using a TGA-DTA
connected to an FTIR for evolved gas analysis. One appli-
cation of this material has been tested, where it was com-
pounded in an extruder with polymer to form a strong,
322 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
lightweight composite material. The physical and chem-
ical properties of the composite were determined with a
mechanical tester, a gas pycnometer and the TGA-DTA-
FTIR system. The activation energy for composite decom-
position was generally found to be double that of pure
polymer, thus resulting in a material with higher thermal
stability. Moreover, any CO2 in carbonate form encapsulat-
ed within the polymer was only released upon decomposi-
tion at temperatures above the composite’s melting point,
thus effectively increasing its thermal stability more than
twofold. Composites containing high levels of CO2-loaded
biomass displayed values of yield stress and elasticity
modulus that indicate the composite can be applied in
several areas where polymers are commonly used, e.g.
packaging, furniture, automobiles, construction, etc. There-
fore a method to capture and utilize CO2 was demonstrat-
ed, which avoids the high costs and logistics associated
with storage underground. This new material is very prom-
ising because of its CO2 capture effectiveness, simple pro-
duction process, low energy consumption and relatively
low cost. Ultimately this process is sustainable and can
be commercialised, thus generating economic and envi-
ronmental benefits at the same time.
INVESTIGATIONS ON SUPERCRITICAL TRANSESTERIFICATION OF VEGETABLE OILS AND ANIMAL FATS FOR BIODIESEL PRODUCTION AT TEMPERATURES 300-400 ºC AND 9:1-15:1 ALCOhOL MOLAR RATIOS
323
INVESTIGATIONS ON SUPERCRITICAL TRANSESTERIFICATION OF VEGETABLE OILS AND ANIMAL FATS FOR BIODIESEL PRODUCTION AT TEMPERATURES 300-400 ºC AND 9:1-15:1 ALCOhOL MOLAR RATIOS
victor fernando MarulandaUniversidad de La Salle;
Cra 2 # 10-70, 57, Bogota, Cundinamarca, Colombia; E-mail: [email protected]
Supercritical transesterification has been proposed as an
alternative to the conventional base catalyzed process for
biodiesel production due to its apparent advantages re-
lated to the feasibility to use cheaper triglyceride feed-
stocks, and a simpler process resulting of the elimination
of the use of a catalyst in the final product purification. In
this aspect, most of the experimental studies have been
carried out at temperatures 300-350 ºC and alcohol to oil
molar ratios higher than 40:1, higher temperatures have
been associated to a deterioration of the fuel quality. More
recently, several studies have been conducted at tempera-
tures around 400 ºC and lower reactant ratios. Though
initially focused on improving economic and environmen-
tal performance indicators of the supercritical process, the
experimental results have shown the high temperature
promotes several reactions of decomposition of long chain
esters and glycerol into short chain esters and glycerol
ethers, which have the potential to improve certain prop-
erties of the fuel such as viscosity and cold flow. In this
work the experimental results of the batch and continuous
supercritical transesterification of chicken fat, bovine fat
and crude palm oil with methanol and ethanol at tem-
peratures 300-400 ºC and 9:1-15:1 alcohol molar ratios are
324 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
discussed. Qualitative as well as quantitative product anal-
ysis by GC-MS indicates a conversion of triglycerides near
to completion at 400 ºC and residence times of 12, 15 and
30 minutes for chicken fat, crude palm oil and bovine fat,
respectively. The different times can be associated to the
alcohol used in the transesterification, methanol or etha-
nol, the first one being more reactive, and the triglyceride
composition of the raw material. Short chain methyl esters
as well as linear hydrocarbons not initially present in the
raw material were identified in the produced biodiesel.
Though short chain esters have lower boiling points and
viscosities than the longer ones, which positively affect
the product, the cetane number is lower. However hydro-
carbons have a higher cetane number that could make up
for the apparent reduction or deterioration of the fuel qual-
ity. Glycerol ethers, resulting from methylation/ethylation
reactions of glycerol were also identified in the product.
Some of these products remained in the biodiesel phase
and could act to improve certain properties of the fuel or
be considered fuel additives. In this aspect, the studied
supercritical process could offer a feasible technical alter-
native to the glycerol byproduct, currently considered a
waste problem for the biodiesel process due to the high
cost of its purification and low prices in the market.
PRECIPITATION AND ENCAPSULATION OF BIOACTIVE COMPOUNDS USING SUPERCRITICAL TEChNOLOGy
325
PRECIPITATION AND ENCAPSULATION OF BIOACTIVE COMPOUNDS USING SUPERCRITICAL TEChNOLOGy
natália Mezzomo, sandra R. s. ferreiraFederal University of Santa Catarina (UFSC), EQA/CTC; CP 476 – Trindade, 88040-900, Florianópolis, SC, Brazil;
E-mail: [email protected]
Natural products are relevant sources of compounds with
biological activity, which are technologically important for
employment in chemical, pharmaceutical and food indus-
tries. The growing interest of these industries in natural
extracts foments researches of their recovery using tech-
nologies that allow high quality production. Due to the
molecular structure and high unsaturation rate of these
compounds, factors like heat, light and presence of acids
cause their isomerization, with loss and/or diminution of
the biological properties. Thus, aiming at industrial appli-
cation of these extracts, the study of methods enabling
their stabilization, as encapsulation in polymers, is im-
portant. The objective of this project is to study the encap-
sulation of bioactive extracts through the processes of
Supercritical Anti-Solvent (SAS) and Supercritical Fluid
Extraction of Emulsions (SFEE), seeking the production
of stable micro/nano-particles. For both methods applica-
tion, a flexible unit that can be used for Supercritical Fluid
Extraction (SFE), SAS and SFEE is being executed. The
evaluation of SAS unit is being performed throughout the
precipitation of sodium ibuprofen, a well-known nonste-
roidal anti-inflammatory drug considered model material
for crystallization processes. The primary solvent used was
acetone and the anti-solvent applied was supercritical CO2.
326 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
The following ranges evaluated the SAS process: pressure
(80-140 bar), temperature (35-55 ºC ), solute concentration
(0.5-1.5 mg/mL), solution flow rate (1-3 mL/min) and con-
stant CO2 flow rate of 1 kg/h. The particles obtained from
all conditions were evaluated by their size and morphol-
ogy, using a scanning electronic microscopy (SEM), the
thermal profiles by differential scanning calorimetry (DSC),
and the crystallinity using x-ray diffraction (XRD). The av-
erage particle sizes of the SAS-precipitated ibuprofen were
below 380 ± 84 nm for all the conditions tested in the
experiments, which means that the size of the original
particles was reduced from micrometric (non-processed
sodium ibuprofen) to nanometric order (SAS particles). The
best SAS operational conditions, in order to produce the
lowest ibuprofen particle size, were 0.5 mg_ibuprofen/mL,
1 mL_solution/min, 1 kg_CO2/h, 110 bar and 35 ºC. Besides
reducing the ibuprofen particle size, the SAS process ap-
pears to have purified the original sodium ibuprofen, accord-
ing to the thermal analysis of processed and non- processed
ibuprofen particles. The XRD results indicated that SAS
process at 1 mg_ibuprofen/mL, 1 mL_solution/min, 1 kg_
CO2/h, 110 bar and 35 ºC are the best conditions to obtain
ibuprofen particles with higher crystallinity. The sequence
of the project is the SAS study applied to natural extracts
encapsulation. It is being studied the SAS encapsulation
of extract from grape pomace in poly(lactic-co-glycolic)
acid (PLGA), varying the operational variables (pressures
of 80-140 bar temperature of 35-45 ºC, solution flow rate of
1-3 mL_solution/min, constant CO2 flow rate of 1 kg_CO
2/h),
and verifying their influence in the quality of particles
produced (particle size and shape by SEM analysis, inter-
action between encapsulant and encapsulated materials
through the DSC). The future project activities are to adjust
the SFE/SAS unit to the SFEE process and apply it to nat-
ural extracts encapsulation.
327
IDTq — A NEW RESEARCh GROUP LOCATED IN CORDOBA, ARGENTINA: PhASE EqUILIBRIUM AND ITS APPLICATION TO IMPREGNATE BIOPOLyMERS AND TO DESIGN DRUG DELIVERy SySTEMS
Juan M. Milanesio, Alfonsina E. Andreatta* IDTQ – Grupo Vinculado PLAPIQUI – CONICET – FCEFyN,
Universidad Nacional de Córdoba; Av. Vélez Sarsfi eld 1611, Córdoba, Argentina
* Facultad Regional San Francisco, Universidad Tecnológica Nacional;
Av. de la Universidad 501, San Francisco, Córdoba, Argentina
cesar gomez, Miriam striumiaDepartamento de Química Orgánica,
Facultad de Ciencias Químicas, Universidad Nacional de Córdoba;
Haya de la Torre y Medina Allende, Edifi cio de Ciencias II, Ciudad Universitaria, Córdoba, Argentina
Lidia QuinzaniPLAPIQUI – Planta Piloto de Ingeniería Química,
Universidad Nacional del Sur – CONICET, Cno.;La Carrindanga km. 7, Bahía Blanca, Argentina;
E-mail: [email protected]
IDTQ is a recently developed research group with a high
potential and mainly focused on supercritical technology
applied to the extraction of natural products and its use
on human health, and also applied to solve energy problems.
Also, the extracted bioactive compounds are being
studied to develop new drug delivery systems using poly-
mers with supercritical technology. The synthesis of polymers
from glycerol or its derivatives and their application to de-
velop controlled release drug delivery systems are one of
the main interests in our research group.
Plants with important properties for human health
accompany mankind from its origins. In spite of the great
evolution of health sciences, pathologies still exist without
328 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
a definitive cure or with therapies that cause undesirable
effects. Within this frame it is necessary to search new
therapeutic agents.
Glycerol is a polyfunctional molecule, with three
alcohol groups and with a high reactivity and versatility
[1]. Using esterification reactions it is possible to develop
new polymers with surfactant properties [1]. These poly-
mers, with a hydrophilic and a hydrophobic region, can
be used for drug encapsulation [2-5] using supercritical
technology for particle precipitation [6]. Particularly, they
can be used as carriers for highly hydrophobic drugs inside
micelles, like cancer chemotherapy drugs [2, 4-5]. In this
work we will present preliminary results for the synthesis
of polymers via glycerol esterification and from glycerol
carbonate, and its application for designing controlled
release drug delivery systems. Within the scope of these
preliminary results are phase equilibrium data for glyc-
erol, carbon dioxide and the polymers.
REFERENCES
[1] C. H. Zhou, J. N. Beltramini, Y. X. Fan, G. Q. Lu, Chemoselective cat-
alytic conversion of glycerol as a biorenewable source to valuable
commodity chemicals, Chemical Society Reviews, 37 (2008) 527-549.
[2] M. E. Fox, F. C. Szoka, J. M. J. Fréchet, Soluble polymer carriers for
the treatment of cancer: The importance of molecular architecture,
Accounts of Chemical Research, 42 (2009) 1141-1151.
[3] J. Green, Z. Tyrrell, M. Radosz, Micellization of poly(ethylene glycol) -
block-poly(caprolactone) in compressible near critical solvents, J. Phys-
ical Chemistry C, 114 (2010) 16082-16086.
[4] L. Y. Lee, S. H. Ranganath, Y. Fu, J. L. Zheng, H. S. Lee, C. H. Wang,
K. A. Smith, Paclitaxel release from micro-porous PLGA disks, Chem-
ical Engineering Science, 64 (2009) 4341-4349.
[5] Z. L. Tyrrell, Y. Shen, M. Radosz, Multilayered nanoparticles for con-
trolled release of paclitaxel formed by near-critical micellization of tri-
block copolymers, Macromol, 45 (2012) 4809-4817.
[6] S. D. Yeo, E. Kiran, Formation of polymer particles with supercritical
fluids: A review, J. Supercritical Fluids, 34 (2005) 287-308.
COMPRESSED GASES FOR ThE SEPARATION OF BIOMASS FROM IONIC LIqUID MIxTURES
329
COMPRESSED GASES FOR ThE SEPARATION OF BIOMASS FROM IONIC LIqUID MIxTURES
David L. Minnick, Aaron M. scurtoDepartment of Chemical & Petroleum Engineering
and Center for Environmentally Benefi cial Catalysis, University of Kansas;
5234 Eisenhower Terrace, 66049, Lawrence, Kansas, USA;E-mail: [email protected]
Identifying cost-effective renewable energy sources is vi-
tal as the world continues to experience a strain on fossil
fuels. Cellulose, the world’s most abundant natural bio-
polymer, presents an inexpensive, carbon-neutral feedstock
for the production of bio-fuels and bio-chemicals. Howev-
er, the rigid hydrogen bonding network between cellulose
molecules renders it insoluble in nearly all organic solvents.
Select ionic liquids (ILs) including 1-butyl-3-methylimidaz-
olium chloride [BMIm][Cl] and 1-ethyl-3-methylimidazolium
diethyl phosphate [EMIm][DEP] are capable of dissolving
significant quantities of cellulose. Once dissolved the cel-
lulose can undergo one of two routes: 1) direct conversion
to glucose via hydrolysis or 2) precipitation. In the first pro-
cess, cellulose derivatization results in monomeric glucose
subunits that can be used for energy, or further processed
into high-value chemicals. Alternatively, precipitating the
cellulose out of the IL yields a less-crystalline, pre-processed
form with a wide range of applications. Regardless of the
desired end product, an extraction technique must be
performed to separate the final product and ionic liquid.
Anti- solvent methods have been proposed whereby large
quantities of anti-solvent are mixed with the IL solution
to crystallize the product, resulting in solid-liquid phase
330 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
equilibria (SLE). While effective, the excessive quantities
of anti-solvent required to separate cellulose and glucose
from ionic liquids negatively impacts the feasibility of these
processes from sustainability and economic standpoints.
Here we propose a competing process to selectively re-
move cellulose and glucose from ionic liquids using com-
pressed CO2 by altering the phase behavior of these systems.
For the IL:glucose system, two extraction methods have
been observed. First, CO2 at moderate pressure is capable
of converting this system from vapor-liquid equilibria (VLE)
to vapor-liquid-solid equilibria (VLSE) phase behavior, thus
precipitating the pure glucose product for separation by
filtration. Second, high pressure CO2 can transform certain
IL/glucose/solvent systems from vapor-liquid equilibria
(VLE) to vapor-liquid-liquid equilibria (VLLE) phase behav-
ior where glucose is extracted into the organic or aqueous
(non-IL) liquid phase for separation. These same process-
es are applicable to the separation of cellulose from ILs
and will be demonstrated. Compressed carbon dioxide is
a promising alternative to conventional organic anti-sol-
vents for extracting glucose and cellulose from ionic liq-
uids. Our results will display how high pressure CO2 can
alter the phase behavior of these systems and the result-
ing glucose/cellulose separations.
OBTAINING ExTRACTS FROM CLOVE (EugEniA cARyophyLLus) AND ANNATTO (BixA oRELLAnA L.) USING SUPERCRITICAL FLUID ExTRACTION IN A CONTINUOUS OPERATING MODE
331
OBTAINING ExTRACTS FROM CLOVE (EugEniA cARyophyLLus) AND ANNATTO (BixA oRELLAnA L.) USING SUPERCRITICAL FLUID ExTRACTION IN A CONTINUOUS OPERATING MODE
Moyses n. Moraes, giovani L. Zabot, M. Angela A. Meireles
LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas);
R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]
The goal of obtaining increasingly natural products of high
purity is leading researchers to use more suitable extrac-
tion processes, known as “green processes”. Thus, super-
critical fluid extraction (SFE) is receiving increased attention,
because it is a green technology that yields distinct ex-
tracts relative to those obtained in the conventional extrac-
tion processes. The resulting SFE waste, which is considered
a better co-product, is the vegetal matrix, free of target
compounds; the matrix can be used as the raw material
for other integrated processes. The maximum utilization
of raw materials is a current subject in interest. Likewise,
the productivity of a process can be improved by incorpo-
rating the continuous extraction of bioactive compounds.
Understanding the influence of various parameters on the
continuous extraction process is the target for implementing
the supercritical technology on an industrial scale. The ex-
traction time, the amount of solvent, the shape of the
extractors and the characteristics of the raw materials are
some of the parameters known to influence the techno-
economic aspects of such processes. Further, the use of a
range of extraction vessels is necessary to accomplish the
operation. In this sense, we assembled an apparatus with
two one-liter extractors to obtain two extracts in continu-
332 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
ous mode using supercritical CO2, including (1) a volatile
oil from clove buds and (2) an extract rich in tocotrienols
from annatto seeds. These two vegetal matrices were se-
lected because they contain volatile oil and pigments with
health benefits, which are in high demand in the global
market. The high quantity of bixin in the annatto extracts
allows for strong colorant action. Additionally, both raw
materials can be used, after extraction, in the hydrolysis
of the lignocellulosic structure for producing fermentable
sugars. In this context, the proposed system was found to
be efficient because it was possible to reach significant
extraction yields in short times in comparison to batch
processes. When one extractor was in the charge/discharge
step, the other was used for extraction, which allowed the
product to be continuously obtained. Based on laboratory
experiments, some parameters were defined as suitable
parameters for use in the continuous mode. For clove oil
(1), the ideal CO2 mass to feed mass (S/F) was approxi-
mately 1.9 (corresponding to 60 min of extraction and 80 g
of extract/100 g of extractable). For the annatto extract (2),
the ideal S/F was approximately 2.7 (corresponding to 90
min of extraction and 66 g of extract/100 g of extractable).
From the economic perspective, the use of supercritical
CO2 extraction in a continuous mode reduces the payback,
which is the time needed to match the net profit with the
initial amount of capital invested.
ACKNOWLEDGEMENTS
The authors acknowledge the financial support from CAPES (DEA/FEA/
PROEX); partial support from FAPESP (2009/17234-9 and 2012/10685-8)
is also acknowledged. M. N. Moraes thanks CAPES and G. L. Zabot thanks
FAPESP (2011/23665-2) for the Ph.D. assistantships. M. A. A. Meireles
thanks CNPq for the productivity grant (302778/2007-1).
ESTIMATION OF COSTS IN SUPERCRITICAL CO2 ExTRACTION PLANTS OF SOLID SUBSTRATES By SIMULATION PROCESS
333
ESTIMATION OF COSTS IN SUPERCRITICAL CO2 ExTRACTION PLANTS OF SOLID SUBSTRATES By SIMULATION PROCESS
gonzalo A. núñez, José M. del valleUniversidad Técnica Federico Santa María;
Av. Vicuña Mackenna 3939 San Joaquín, Santiago, Chile;E-mail: [email protected]
Supercritical fluid extraction of solid substrates has been
applied commercially for a long time to several applica-
tions (including extraction of hops, decaffeination of coffee
beans, extraction of flavors from herbs and spices, extrac-
tion of oilseed, among others). Despite of this, in literature
there is little information about scaling-up and costing of
this technology, which generally is part of the know-how
of plant manufacturers. The objective of this work (based
on the doctoral thesis titled “Development of a Simulation
Tool for the Economic Optimization of an Extraction Plant
for Vegetable Substrates Using Supercritical CO2”) is to
present a simulation tool to estimate the costs in an in-
dustrial supercritical CO2 extraction plant and to show the
effect of relevant parameters in the extraction process.
Particularly, this work presents estimates for operational
and production costs of the supercritical CO2 extraction
of prepressed oilseeds using a novel simulation algorithm
based on the fully predictive shrinking core model for the
inner mass transfer. Operational costs (<9 USD/kg of oil)
decrease when particle size decreases and superficial CO2
velocity increases. Production costs (estimated <13 USD/
kg of oil) include the capital cost, which is one of the items
with major uncertainties in the estimates. Under the same
extraction conditions, a decreasing of the aspect ratio (L/D)
334 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
of the extraction vessels has a positive effect on production
cost. In two-vessel plant, the lowest production cost was
reached at highest extraction pressure (70 MPa). However,
in multi-vessel plants, the minimum production cost was
at 50 MPa. In all cases studied, the number of extraction
vessels and the total volume of the plant had a positive
effect on production cost, confirming that economies of
scale apply to this process. Other factors as optimal ex-
traction time, exhaustion grade of the substrate, and pro-
ductivity of the plant should be taken in count to make
decisions about investment or to optimize the operation
of an industrial plant. Finally, the methodology developed
in the thesis can be adapted to others solid substrates
using a proper mass transfer model. This work will present
the adaptation of the simulation tool to the extraction of
tomato with supercritical CO2 using the Desorption-Dis-
solution-Diffusion (DDD) mass transfer model with a Fre-
undlich isotherm to describe the partition of the solute
between the solid matrix and the supercritical phase.
OVERVIEW OF ThE hIGh PRESSURE TEChNOLOGy AND NATURAL PRODUCTS LABORATORy OF ThE UNIVERSITy OF SãO PAULO IN DEFENSE OF ThE TEChNOLOGICAL INNOVATION
335
OVERVIEW OF ThE hIGh PRESSURE TEChNOLOGy AND NATURAL PRODUCTS LABORATORy OF ThE UNIVERSITy OF SãO PAULO IN DEFENSE OF ThE TEChNOLOGICAL INNOVATION
Alessandra L. oliveiraDepartamento de Engenharia de Alimentos (ZEA),
Faculdade de Zootecnia e Engenharia de Alimentos (FZEA); Avenida Duque de Caxias Norte, 225, 13635-900, Pirassununga, SP, Brazil;
E-mail: [email protected]
The High Pressure Technology and Natural Products Lab-
oratory (LTAPPN ) is a new research laboratory of the Food
Engineering Department, Faculty of Animal Science and
Food Engineering of the University of São Paulo. Created
in 2003 under the responsibility of Prof. Dr. A.L. Oliveira,
it conducts physical separations research employing high-
pressure systems. Initial work was aimed to study the
separation extracts rich in active compounds from natural
Brazilian flora (Guaco, Pitanga fruit) using supercritical
CO2 and thermodynamic modeling of the solubility of these
compounds in this supercritical solvent using equations
of state. Currently, the work continues to be developed
for this purpose, using separation processes with super-
critical fluid (SFE) and pressurized liquid extraction (PLE)
with pressurization by means of nitrogen. The modeling
of separation processes continues to be practiced using
equations of state for the solubility study and numerical
simulation in transport phenomena. Research are direct-
ed to extraction optimization of Pitanga seeds, flour from
Babaçu mesocarp and Pequi, characteristic fruit from Bra-
zilian Cerrado using SFE and PFE. These studies aim to
demonstrate that technological innovation is able to get
336 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
these extracts with efficiency and quality when consider
the maintenance of their activities. Specifically for euca-
lyptus oil, it is noteworthy that Brazil is the world’s largest
exporter. However, the extraction method is rudimentary
and this disqualifies it regarding the decomposition of its
main compound due to high temperatures employed in
the process. The study of the supercritical extraction op-
timization, another work in progress in LTAPPN, allowed
to achieve high yields of essential oil rich in citronellal and
a second product, the oil resin, rich in phenol compounds
with high antioxidant activity. This oil resin is an unknown
product for the producers of eucalyptus essential oil in
Brazil. The high-pressure processes are also being used
in the pretreatment of lignocellulosic waste material to be
employed in enzymatic processes aimed for sugar produc-
tion from sugar cane bagasse for ethanol manufacture or
xylose from coconut fiber. The appeal of this technology
application is linked to supply clean raw materials and
consequently without contaminants that negatively inter-
fere in the enzymatic process. The oil from green coffee
beans is one of the main subjects of study in this labora-
tory. In this research development there is a French insti-
tution collaboration (ICOA, Université d’Orléans). This study
aims to enrich the green coffee oil with its main diterpenes
(cafestol and kahweol) with chemoprotective action. In
this laboratory is also developed research using fish waste
from Brazilian industry, studying conditions for enrichment
of shark liver oil in its main component, the squalene with
several biological activities. The LTAPPN has ten graduate
students with instruction in different knowledge domains,
which makes it possible to perform researches in collab-
oration with other international and Brazilian laboratories
aiming for the application of these extracts for specific
purposes as medicine action. For example, the used of
POSTERS 337
Pitanga seeds extract against leishmaniasis and the study
in vivo of green coffee oil chemoprotective action. The most
recent research line investigated in LTAPPN directs to the
microencapsulation of natural extracts, volatile or not,
using Rapid Expansion of Supercritical Solution (RESS)
system using polymers of low commercial value. Sensory
analysis is also a common subject in this laboratory works
since it is used as a tool for evaluating the aromatic vola-
tile compounds quality in the extraction or encapsulation
process. The LTAPPN aims to contribute in demonstrating
that technological innovation can be feasible if the re-
search results might increase some extracts value by new
extraction methodology or even by the fractionation pos-
sibility and consequent enrichment in active compounds.
Regarding the interaction University/Company, the LTAPPN
has collaboration or/and development with some compa-
nies as Ingredion Brazil, O Boticário and SPF Palatability
Brazil.
SUPERCRITICAL TEChNOLOGy APPLIED TO ThE REUSE OF PASSION FRUIT RESIDUE
339
SUPERCRITICAL TEChNOLOGy APPLIED TO ThE REUSE OF PASSION FRUIT RESIDUE
Daniela Alves de oliveira, sandra R. s. ferreiraFederal University of Santa Catarina (UFSC), EQA/CTC; CP 476 – Trindade, 88040-900, Florianópolis, SC, Brazil;
E-mail: [email protected]
The passion fruit juice production engenders a large amount
of residues such as seeds and rind. Despite the current
efforts from companies to reuse process residues, large
amounts of passion fruit seeds are still underutilized by
the industries. Part of it has been used to produce seed
oil, due to its high content of unsaturated fatty acids, es-
pecially linoleic acid (up to 70%) finding various applica-
tions in the food, pharmaceutical and cosmetic industries.
Still, in the residue of the cold press oil production — the
seed cake — remains fatty acids, phenolic compounds
and proteins of interest. Phenolic compounds are known
to possess biological activities but due to the molecular
structure and high unsaturation rate of these compounds,
factors like heat and light can cause loss and/or diminu-
tion of their biological properties. The literature reports the
antioxidant and antitumor activities of the passion fruit
seed oil or from specific compounds present in the oil, but
few studies are found concerning the supercritical tech-
nology to obtain passion fruit oil and/or biologically active
derivatives. Thus, the study of methods enabling the ex-
traction of interest compounds from passion fruit seeds
and their stabilization, as precipitation and encapsulation
with polymers, may add value to this residue. The present
study aims: (a) to apply the supercritical fluid extraction
340 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
(SFE) on passion fruit seeds and seed cake and compare
it to two different extraction techniques by evaluating their
performances in terms of process yield, total phenolic con-
tent (TPC), antioxidant activity (AA) and composition of
extracts; (b) based on previous results, to select one of the
supercritical extracts to perform phase equilibrium exper-
iments to determine a range of operational conditions to
be employed on precipitation/encapsulation assays. Ex-
traction methods used were: supercritical fluid extraction
(SFE) with CO2 (scCO
2), conducted at 40 °C and 50 °C with
pressures of 150 and 250 bar and 0.5 kgCO2/h; and the
low pressure techniques (LPE) of cold maceration (MAC)
and ultrasonic assisted extraction (UE) using different or-
ganic solvents. The best yield results were obtained by SFE
at 250 bar and 40 °C for the seed (27 ± 1%) and by MAC
with 50% ethanol for cake (6 ± 1%). The cake UE per-
formed with 50% ethanol presented the highest TPC result
determined by the Folin-Ciocalteau method (336 ± 22
mggallic acid equivalents/gextract) and the best AA using
the β-carotene bleaching method (88.8 ± 0% AA after
120 min). The precipitation/encapsulation of bioactive ex-
tracts with poly(lactic-co-glycolic) acid (PLGA) will be done
through the processes of Supercritical Anti-Solvent (SAS)
and Supercritical Fluid Extraction of Emulsions (SFEE)
varying the operational variables and verifying their in-
fluence in the quality of particles produced, seeking the
production of stable micro/nanoparticles. For both precip-
itation/encapsulation methods, a flexible unit that can be
used for SFE, SAS and SFEE is being adapted. The parti-
cles obtained from all conditions will be evaluated by their
size and morphology, using a scanning electronic micros-
copy (SEM), by the interaction between encapsulant and
encapsulated materials through the thermal profiles using
differential scanning calorimetry (DSC), and their crystal-
linity using x-ray diffraction (XRD).
ThE ExTRACTION, MICRONIzATION AND ENCAPSULATION OF CURCUMINOIDS FROM TURMERIC (cúRcuMA LongA L.) USING PRESSURIzED LIqUIDS AND SUPERCRITICAL FLUIDS
341
ThE ExTRACTION, MICRONIzATION AND ENCAPSULATION OF CURCUMINOIDS FROM TURMERIC (cúRcuMA LongA L.) USING PRESSURIzED LIqUIDS AND SUPERCRITICAL FLUIDS
Juan f. osorio Tobón, Mauricio A. Rostagno, M. Angela A. Meireles
LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas);
R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]
The turmeric (Cúrcuma longa L.) plant is widely cultivat-
ed in countries and regions with tropical and subtropical
climates. Turmeric has been used since ancient times as
a condiment, preservative, flavoring, coloring agent and
folk medicine [1]. Turmeric has been investigated for its
biological activity in association with anticancer, antibac-
terial, chemopreventive and chemotherapeutic properties.
Today, turmeric is used mainly as a dye, due to the interest
of replacing synthetic additives with natural compounds
[2]. The yellow color of the rhizomes is due to the presence
of a group of phenolic compounds called curcuminoids.
There are three main curcuminoids, including curcumin (I),
demethoxycurcumin (II) and bisdemethoxycurcumin (III).
Curcuminoids have traditionally been extracted by
liquid-liquid extraction and Soxhlet. Today, the need to
develop more efficient processes and avoid the use of or-
ganic solvents has facilitated the development of more
rapid and environmentally friendly techniques, such as
pressurized liquid extraction (PLE).
PLE is performed under a wide range of conditions
with a compressed liquid. In this region, the liquids are
342 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
highly incompressible, and when the solvents are sub-
jected to pressure changes at constant temperature, the
solvent density and solvation power are insignificantly
affected [3]. However, the use of increased temperatures
improves the efficiency of extraction due to the enhanced
rate of mass transfer and diffusion rates [4].
Several techniques are used for the production of
micro-particles, such as spray-drying, spray-cooling and
spray-chilling; however, these methods possess several
disadvantages, such as product degradation, contamina-
tion with organic solvents and the production of large-size
particles [5]. For this reason, supercritical antisolvent pre-
cipitation (SAS) and supercritical fluid extraction of emul-
sions (SFEE) have been proposed as alternatives to the
conventional micronization techniques.
In the SAS process, a liquid solution containing the
solute to be micronized is brought into contact with a su-
percritical fluid (SCF). Therefore, the contact between the
liquid solution and the SCF induces the formation of a
solution, producing the condition of supersaturation and
causing solute precipitation. Several differences exist be-
tween SAS processes and that of SFEE: an emulsion con-
taining the desired substance to be precipitated, which is
dissolved in the SFC, is injected instead of injecting a sim-
ple solution of the substance, causing the formation of a
liquid product.
The objective of this work is to develop a PLE pro-
cess for curcuminoids and to study the micronization and
encapsulation of the extracts obtained by PLE through
supercritical fluids. To meet this objective, the temperature
and pressure effects will be studied relative to the total
yield of curcuminoids in the PLE process. To eliminate the
organic solvent and produce micro- and nanoparticles,
the effects of temperature, pressure and flow on the SAS
POSTERS 343
and the SFEE processes will be evaluated. The curcumi-
noids will be quantified by HPLC. The morphology and
particle size distributions of the micro- and nanoparticles
obtained by SAS and SFEE will be acquired using scan-
ning electron microscopy. Precipitation yield and encap-
sulation efficiency will be determined. The impact of the
different factors on the cost of manufacture will be eval-
uated using SuperPro Designer®.
ACKNOWLEDGEMENTS
Authors are grateful to CNPq (470916/2012-5) for the financial support;
partial support from FAPESP (2012/10685-8) is also acknowledged. Juan
F. Osorio-Tobón thanks CAPES for the PhD assistantship. M. A. A. Meireles
thanks CNPq for the productivity grant (302778/2007-1).
REFERENCES
[1] C. A. C. Araujo, L. L. Leon, Biological activities of Curcuma longa L.,
Memorias Do Instituto Oswaldo Cruz, 96 (2001) 723-728.
[2] P. N. Ravindran, K. N. Babu, K. Sivaraman, Turmeric: The genus Curcuma,
Taylor & Francis, 2007.
[3] C. C. Teo, S. N. Tan, J. W. H. Yong, C. S. Hew, E. S. Ong, Pressurized
hot water extraction (PHWE), J. Chromatography A, 1217 (2010) 2484-
2494.
[4] D. T. Santos, P. C. Veggi, M. A. A. Meireles, Optimization and econom-
ic evaluation of pressurized liquid extraction of phenolic compounds
from jabuticaba skins, J. Food Engineering, 108 (2012) 444-452.
[5] M. J. Cocero, A. Martin, F. Mattea, S. Varona, Encapsulation and co-
precipitation processes with supercritical fluids: Fundamentals and
applications, J. Supercritical Fluids, 47 (2009) 546-555.
MOLECULAR ThERMODyNAMICS ANALySIS OF BIOFUEL SySTEMS
345
MOLECULAR ThERMODyNAMICS ANALySIS OF BIOFUEL SySTEMS
c. g. pereira, n. ferrando, p. Mougin, J. c. hemptinne
DEQ/CT/UFRN – Federal University of Rio Grande do Norte; Av. Sen. Salgado Filho, 3000 Cidade Universitária,
59078-970, Natal, RN, Brazil; E-mail: [email protected]
Thermodynamics has an important role in several indus-
trial sectors, representing the basis in the development of
projects, products as well as in the simulation steps and
process optimization. Thermodynamic equations and mod-
els are used as a tool to support operational decisions.
Over the years, the industry challenge has been to under-
stand the behavior of different systems to improve a pro-
cess or to obtain a particular product. Nonetheless, the
focus changes according to the interests of each area.
Nowadays, the necessity of the environmental preserva-
tion and the requirements from the government, agencies
and society for the use of sustainable products and pro-
cesses has driven the search for new technologies. Since
fuel originating from biomass becomes a real alternative
for petroleum fuel and started to be commercially produced
several studies has been done in order to understand the
systems involved in its processing. Biodiesel is a renewable,
biodegradable and environmentally correct substitute to
mineral diesel, produced through the transesterification
reaction of triglycerides with any short-chain alcohol, such
as methanol or ethanol. The result of this reaction is a mix-
ture of ethyl or methyl esters of fatty acids (biodiesel) and
glycerol. Recent studies have also considered supercritical
346 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
or compressed fluids as alternative routes for the separa-
tion and purification steps of biodiesel. When dealing with
separation units the knowledge of the phase equilibria is
essential to evaluate systems in real processing conditions.
In statistical thermodynamics, the properties of a bulk sys-
tem are determined based on the interactions between
the molecules constituting the system. The detailed mo-
lecular interactions (repulsive and attractive) within com-
plex fluids can be evaluated by the three categories of
equations of state (cubic, lattice and perturbation). The
analysis of intermolecular forces present in the system
represents a fundamental role in the understanding and
application of these models. Among the perturbation the-
ories, SAFT (Statistical Associating Fluid Theory) is in-
creasingly used. This EoS explicits in the equation terms
related to the effect of dispersion, chain formation and
association in the molecule. Several variations of SAFT
were derived from the original model [1] (CK-SAFT, PC-
SAFT, SAFT-VR, others). The GC-PPC-SAFT (Group Con-
tribution Polar Perturbed-Chain — SAFT) combines a group
contribution method [2] with the PC-SAFT EOS [3] and an
additional polar contribution. It has demonstrated good
results for different classes of compounds such as esters,
ethers, ketones, alcohols, amines, aromatic/polyaromatic
compounds, and their mixtures. Concerning additional pre-
dictive models, Molecular Simulation has also been suc-
cessful in calculating properties of complex systems. More
specifically, the Monte Carlo simulation technique has been
successfully used to predict phase equilibria of systems
of industrial interest. The present work presents a predictive
analysis of phase equilibrium of systems involved in the
biofuel processing. The experimental data from literature
were compared with predicted values using GC-PPC-SAFT,
PSRK equations of state and molecular simulation. Pre-
POSTERS 347
dictive multiphase equilibria was computed for the sys-
tems: alcohol (ethanol or methanol) + ethyl or methyl esters;
alcohol + glycerol; biofuel blends. The predicted values
showed to be consistent with new experimental data.
REFERENCES
[1] M.S. Wertheim, J. Statistical Physics, 35 (1986) 35.
[2] S. Tamouza, J.P. Passarello, P. Tobaly, J.C. de Hemptinne, Fluid Phase
Equilibria, 222 (2004) 67.
[3] J. Gross, G. Sadowski. Industrial & Engineering Chemistry Research,
40 (2001) 1244.
PILOT PLANT CONCEPT FOR hyDROGEN GENERATION By BIOMASS GASIFICATION IN SUPERCRITICAL wATER INTEGRATED WITh A ThERMOELECTRIC UNIT (h2-BGSCW/TEU)
349
PILOT PLANT CONCEPT FOR hyDROGEN GENERATION By BIOMASS GASIFICATION IN SUPERCRITICAL wATER INTEGRATED WITh A ThERMOELECTRIC UNIT (h2-BGSCW/TEU)
Daltro garcia pinatti, Rosa Ana conteDepartamento de Engenharia de Materiais,
Escola de Engenharia de Lorena, USP;Polo Urbo-Industrial, s/no., Gleba AI-6, Bairro Santa Lucrécia,
12602-810, Lorena, SP, Brazil; E-mails: [email protected]; [email protected]
hydrothermal processing in supercritical water (SCW) has
many advantages over steam [1]: complete sterilization of
pathogens, three regions of hydrothermal process (lique-
faction, catalytic reforming/ gasification, and high tempera-
ture gasification), properties variation of water (density,
solvation power, gas miscibility, and salt crystallization),
biomass drying is unnecessary, high versatility of chemis-
try, enhancement of reaction rates and efficient separation,
and SCW does not have phase transitions. After decades
of development SCW is a great success in coal-fired ther-
moelectric units (TEU) [2] due to the use of ppb-purity
water and Benson boiler. Partial or total replacement of
coal by biomass pellets is under development. SCW ap-
plied to other fields is hindered by a number of problems:
corrosion, incrustation, creep at 25 MPa/700 oC, materials
cost, low concentration of biomass and large water vol-
umes, among others. H2-BGSCW/TEU concept developed
by DEMAR-EEL-USP [3,4] is facing those problems with
the following interdisciplinary approaches: (a) functional
separation of materials (FSM) using high performance con-
crete (HPC, 90 MPa) with addition of rice husk silica to
350 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
increase compression resistance, GPa-steel cables to sup-
port tensile strength at room temperature, and castable
refractory for thermal insulation of the pressure vessel; (b)
inside the pressure vessel the reaction tank, heat exchang-
ers and piping are made of thin wall superaustenitic steels,
working at small pressure differences between their walls
at 650 oC; (c) components inside the pressure vessel are
mechanically supported at the bottom at room tempera-
ture and they are free for thermal expansion at the top; (d)
H2-BGSCW reactor is installed between TEU SCW boiler
and turbine; (e) slurry prepared with 5 wt% of clean bio-
mass with addition of activated carbon as catalyst for high
rate H2 production [5]; (f) electric energy hydrostorage (EEHS)
after the first expansion (H2 release) at 12.5 MPa during
19 hours of the day, and expansion in Pelton hydroturbines
at peak hours (3 hours of the day). The last technology
covers the cost of circulation of large volumes of water in
the H2-BGSCW/TEU. The pilot plant concept maximizes
yield of high valued products, minimizes material and cap-
ital investments, utilizes the full capacity of SCW technol-
ogy, and faces up the operational reality of the H2-BGSCW
unit. H2-BGSCW/TEU aims a medium size power plant
(50 MWe, 1300 kg H
2/hr.) to be installed in a distributed way
to incentivize reforestation, nucleation of industrial com-
plexes, generation of employment, revenues and taxes.
REFERENCES
[1] A. A. Peterson et al., Thermochemical biofuel production in hydrother-mal media: A review of sub- and supercritical water technologies, En-ergy Environmental Science, 1 (2008) 32–65.
[2] T. Jäntti, H. Lampenius, M. Ruuskanen, R. Parkkonen, Supercritical OUT CFB Projects-Lagisza 460 MWe and Novercherkasskays 330 MWe, Russia Power Moscow, Russia March 28-30, (2011) TP_CFB_11_04.
[3] D. G. Pinatti, R. A. Conte, Total integration of renewable and fossil energy aiming to a clean and sustainable energy system, J. Energy and Power Engineering, 7 (2013) 58-65.
POSTERS 351
[4] D. G. PINATTI, R. A. CONTE, Scrutiny of available and new technologies
for total integration of renewable and fossil energy for a clean and
sustainable energy system- TIRFE. In: Congress of Bioenergy, April
25-28, 2012, Xi’an, China.
[5] M. J. Antal Jr., S. G. Allen, D. Schulman, X. Xu, Biomass gasification
in supercritical water, Industrial & Engineering Chemistry Research,
39 (2000) 4040-4053.
353
354 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
POSTERS 355
MODELING OF SUPERCRITICAL WATER OxIDATION: hyDROThERMAL FLAMES AS hEAT SOURCE
357
MODELING OF SUPERCRITICAL WATER OxIDATION: hyDROThERMAL FLAMES AS hEAT SOURCE
João paulo silva Queiroz, Maria Dolores Bermejo,
Maria José coceroDepartamento de Ingeniería Química y Tecnología de Medio Ambiente,
Universidad de Valladolid; Calle Doctor Mergelina, s/n. 47011, Valladolid, Spain;
E-mail: [email protected]
Supercritical water oxidation (SCWO) is a useful technolo-
gy for the destruction of waste with residence times lower
than one minute. It takes advantage of the special solva-
tion properties of water above its critical point (374 ºC,
22.1 MPa) to achieve the complete destruction of organic
waste. Oxidation of organics dissolved in supercritical wa-
ter can be carried out in a homogeneous phase due to the
complete miscibility of gases (O2, N
2, CO
2) and organics
with supercritical water. Due to these advantages SCWO
has been also proposed as a technology for replacing com-
bustion in power generation [1,2]. However, some chal-
lenges have still to be overcome for the successful and
profitable commercialization of this technology: corrosion,
salt deposition and high energetic demand [3]. Corrosion
and salt deposition problems, as well as heat recovery
optimization can be avoided by the use of appropriate
materials and reactor designs. The application of reactors
working with a hydrothermal flame as a heat source con-
tributes to overcome many of the challenges present in
supercritical water oxidation technology. Injection of the
reagents over a hydrothermal flame can avoid preheating
problems, such as plugging and corrosion, since the feed
358 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
can be injected at lower temperatures (even room tempera-
ture). Also the kinetics is much faster allowing complete
destructions of the pollutants in residence times lower than
1 s. Next to this, the high temperatures associated to the
hydrothermal flames contribute to a better energy recovery
of the reaction heat for shaft work production. For safety
and material limitations the flame has to be properly in-
sulated or kept in distance from the pressure vessel wall.
The configuration of the reactor and fluid injection nozzle
has to be specially projected for this purpose. Computa-
tional fluid dynamics (CFD) is an essential tool for under-
standing the behavior of actual SCWO reactors and for
predicting the efficiency of new designs.
In this work, the SCWO process is studied through
modeling and simulation:
� Methods of estimation for thermal and transport
properties of supercritical water and mixtures are
studied.
� A new global reaction rate for the oxidation of iso-
propyl alcohol in hydrothermal regime is adjusted
from temperature profiles experimental data. This
kinetic model is applied in a parametric analysis of
flame formation, and it is used to analyze the behav-
ior of a supercritical water oxidation vessel reactors.
The kinetic model is able to describe the behavior
of the vessel reactor when working in steady state
hydrothermal flame regime at subcritical injection
temperatures. The model predicts both flameless
and hydrothermal flame regimes.
� The influence of the internal configuration of vessel
reactors for the Supercritical Water Oxidation Pro-
cess is evaluated by simulation and compared to
experimental data. The CFD-model developed pro-
POSTERS 359
vides a good prediction of the experimental results
and can be used for designing reactors working un-
der hydrothermal flame looking at performance and
flame stabilization. Geometrical and operational
parameters are studied.
� Different turbulence-chemistry interaction theories
are tested.
� The energetic possibilities of the process are ana-
lyzed through calculations. Heat integration, gen-
eration of high pressure steam and generation of
electricity by products expansion, are feasible in
SCWO.
REFERENCES
[1] M. Bermejo, M. Cocero, F. Fernandez-Polanco, A process for generat-
ing power from the oxidation of coal in supercritical water, Fuel, 83(2)
(2004) 195-204.
[2] F. Donatini, G. Gigliucci, J. Riccardi, M. Schiavetti, R. Gabbrielli, S.
Briola, Supercritical water oxidation of coal in power plants with low
CO2 emissions, Energy, 34(12) (2009) 2144-2150.
[3] G. Brunner, Near and supercritical water. part II: oxidative processes,
J. Supercritical Fluids, 47(3) (2009) 382-390.
ThE DEVELOPMENT OF INTEGRATED SySTEMS FOR ThE ANALySIS OF BIOACTIVE COMPOUNDS IN NATURAL PRODUCTS EMPLOyING SUPERCRITICAL TEChNOLOGy
361
ThE DEVELOPMENT OF INTEGRATED SySTEMS FOR ThE ANALySIS OF BIOACTIVE COMPOUNDS IN NATURAL PRODUCTS EMPLOyING SUPERCRITICAL TEChNOLOGy
Mauricio A. Rostagno, M. Angela A. MeirelesLASEFI/DEA/FEA (School of Food Engineering),
UNICAMP (University of Campinas); R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil;
E-mail: [email protected]
The increasing evidence that certain compounds present
in natural products may be useful for the prevention and
treatment of important diseases (such as cancer and car-
diovascular diseases) is prompting the development of new
processes for the production of high-added-value extracts
that are rich in these bioactive compounds. This research
line is focused on the investigation of advanced processes
for the production of high-value-added extracts based on
the combination/coupling of modern techniques in all
stages of production, including the pretreatment of the
raw material, extraction, purification, solvent evaporation,
formation of micro/nanoparticles and encapsulation of the
particles formed.
The processes developed make use of ultrasound
and/or microwave in pre-treatment, a combination of su-
percritical fluid extraction (SFE) or pressurized liquids (PLE)
with ultrasound (UASFE and UAPLE) for the extrac tion of
bioactive compounds from the raw material, solid phase
extraction (SPE) and chromatography (HPLC or SFC) for
the purification of crude extracts obtained in the process-
ing line and supercritical antisolvent process (SAS) or su-
percritical fluid extraction from emulsion process (SFEE),
also used in line to eliminate the use of organic solvents
362 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
/ the formation of micro/nano particles and encapsula-
tion. The high efficiency of these integrated and combined
systems and the associated processes allows for the ex-
ploration of “green” solvents, such as water, ethanol and
supercritical carbon dioxide, as replacements of the tra-
ditionally used toxic solvents, which include methanol and
petroleum ether. Further, using the systems developed, it
is possible to explore these “green” solvents sequentially
for the selective extraction of different components from
the same raw material.
In the same context, the concept of integrating the
different stages of the process and combining the tech-
niques is applied at an analytical scale. Obtaining infor-
mation regarding the concentrations and profiles of bioactive
compounds in natural products is fundamental and has
many applications, ranging from bioactivity studies of func-
tional food and drugs to the control of the production pro-
cess. In this field, research is focused on the development
of highly efficient and fast analysis systems that encom-
pass these same techniques, consisting of coupling be-
tween the sample preparation (extraction and purification)
and chromatographic analysis steps. Sample preparation
is accomplished through a combination of SFE or PLE us-
ing ultrasound (UASFE and UAPLE) and on-line coupling
with the purification by SPE, which in turn also is coupled
on-line with chromatography analysis (HPLC or SFC). The
design of the integrated system allows different proce-
dures to be performed for the extraction, purification and
analysis steps (UAPLE; UASFE; SPE; SFC) or as a single
on-line process (UAPLE/UASFE -SPE, SPE-SFC; UAPLE /
UASFE-SPE-SFC).
In addition to the priority given to “green” solvents,
another key aspect of this technique is sample output. To
reduce the analysis time, new stationary phases are ex-
POSTERS 363
plored (fused-core particles and monolithic columns) in
conjunction with the use of relatively high column tem-
peratures and flow rates (at the analytical scale). Due to
the high efficiency of these new stationary phases, it is
possible to reduce the column dimensions, thereby reduc-
ing the analysis time and solvent consumption. These ad-
vanced systems are mainly used for the development of
“green” methods for the analysis of a wide variety of bioac-
tive compounds (catechins, flavonoids, isoflavones, alka-
loids, curcuminoids, carotenoids and ecdysteroids), which
is present in different types of samples (tea, coffee, soy-
beans, mushrooms, among other natural products).
Besides focusing on the development of integrated
systems and the methods/processes for the analysis/pro-
duction of bioactive compounds from natural products,
this research also addresses the economic aspects of these
technologies through simulations in which the impacts of
different factors on the cost of production and analysis are
evaluated.
NANOSTRUCTURED COMPOSITES OF SILICA AEROGELS WITh hyDROxy-TERMINATED POLy(DIMEThyLSILOxANE) (PDMS(Oh)) By REACTIVE SUPERCRITICAL DEPOSITION
365
NANOSTRUCTURED COMPOSITES OF SILICA AEROGELS WITh hyDROxy-TERMINATED POLy(DIMEThyLSILOxANE) (PDMS(Oh)) By REACTIVE SUPERCRITICAL DEPOSITION
Deniz sanli, can ErkeyKoc University;
Rumeli Feneri Yolu, Koc University Lojmanlar 17/3, Sariyer, 34450, Istanbul, Turkey;
E-mail: [email protected], [email protected]
Vacuum insulation panels (VIPs) with typical thermal con-
ductivities of 3 to 5 mW/mK are emerging as alternative
systems for effective thermal insulation in buildings and
in household appliances. The achievement of such low
thermal conductivities in VIPs relies on the suppression
of the gaseous conduction by applying vacuum. A VIP is
composed of a core insulation material encased in an en-
velope film. Among different materials, fumed silica and
glass fiber are the most commonly utilized core materials
owing to their appreciably low thermal conductivity val-
ues, especially under vacuum conditions. Current VIPs
are not transparent since neither the core materials nor
the envelopes are transparent. However, transparent VIPs
can be attractive alternatives for insulation of certain parts
of buildings in certain climates. Development of transpar-
ent VIPs requires the development of transparent core ma-
terials and barrier films. Silica aerogels appear as the most
promising nanostructured materials to be implemented
as filler materials in transparent VIPs due to their trans-
parency in addition to their low thermal conductivity. One
drawback of silica aerogels is their poor mechanical prop-
erties and this problem can perhaps be overcome by rein-
366 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
forcing aerogels with polymers. In this study, monolithic
composites of silica aerogels with hydroxyl-terminated
poly(dimethylsiloxane) (PDMS(OH)) were developed using
a reactive supercritical deposition technique. The tech-
nique is composed of two stages; the first stage includes
the dissolution of PDMS(OH) in supercritical CO2 that re-
sults in a single phase binary mixture of PDMS(OH)-CO2
and the second stage is the exposure of the silica aerogel
samples to the single phase binary mixture. Initially, the
demixing pressures of PDMS(OH)-CO2 binary mixtures at
various compositions were measured up to 24 MPa to de-
termine the single phase region of the binary mixture. The
demixing pressures were observed to decrease with in-
creasing polymer content of the binary mixture. Subsequent-
ly, deposition experiments were performed with various
PDMS(OH) concentrations and monolithic aerogel compos-
ites were obtained. The polymer uptake of the deposited
aerogels increased with increasing PDMS(OH) concentra-
tion. It was found that the transparency of the aerogels
can be controlled by the amount of the polymer loaded to
the samples. The deposited samples were characterized
by ATR-FTIR and BET analysis. It was revealed that during
the course of the deposition, the polymer molecules react
with the surface –OH groups of the aerogel. The volume
of the polymer in the composites was correlated with the
decrease in the pore volume from the BET results. It was
demonstrated that the deposition resulted in the coating
of silica aerogel surface with a thin layer (~1-2 nm) of
polymer.
ACKNOWLEDGMENTS
We acknowledge the Financial Support of the NANOINSULATE “Devel-
opment of nanotechnology-based High-performance Opaque & Transparent
Insulation Systems for Energy-efficient Buildings Project” being funded
by the EU Program EeB.NMP.2010-1.
ThE DESIGN OF A FUTURE BIOREFINERy BASED ON ThE USE OF SUB/SUPERCRITICAL FLUIDS USING NONTRADITIONAL BIOMASS: BRAzILIAN GINSENG CASE STUDy
367
ThE DESIGN OF A FUTURE BIOREFINERy BASED ON ThE USE OF SUB/SUPERCRITICAL FLUIDS USING NONTRADITIONAL BIOMASS: BRAzILIAN GINSENG CASE STUDy
Diego T. santos, Renata vardanega, M. Angela A. Meireles
LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas);
R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]
Diego T. santos, Juliana Q. Albarelli, Adriano v. Ensinas, françois Maréchal
Industrial Energy Systems Laboratory (LENI), Swiss Federal Institute of Technology Lausanne (EPFL);
Station 9, CH-1015, Lausanne, Switzerland
The refinery concept applies to the full use of biomass,
employing physical and/or chemical treatments for the
production of several commercial products of higher add-
ed value. The sugarcane industry in Brazil, according to
some experts, is only a pioneer for future “biorefineries”.
The growing number of technologies under development
to produce different products with high added value, such
as plant extracts, ethanol and other chemicals, from bio-
mass represents an important aspect that must be thor-
oughly analyzed, especially from the economic point of
view. The use of environmentally friendly sub/supercritical
fluid technologies to obtain products from biomass has
shown encouraging results. However, studies on the at-
tainment of multiple products in an integrated system,
which combines different and sequential processes with
the use of multiple fluids, are essential for the implemen-
tation of future biorefineries. The main goal of this project
is to use the knowledge and tools available for the energy
integration, life cycle analysis and multi-objective opti-
368 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
mization of LENISYSTEM/LENI/EPFL (Switzerland) to
evaluate and optimize the production routes using sub/
supercritical fluids developed experimentally in LASEFI/
DEA/FEA/UNICAMP (Brazil), seeking an integral use of
all parts of Brazilian ginseng (root and aerial parts). There-
fore, it is expected to design a Brazilian ginseng biorefin-
ery based on the use of sub/supercritical fluids. Simulations
of the integrated processes were carried out using the
commercial simulators SuperPro Designer® and Aspen
Plus. Equipment modifications were implemented for the
development of new processes and/or combined process-
es, extending the operational field of LASEFI. Two novel
on-line processes were already developed, including:
a) A process for the pressurized hot organic solvent
extraction of antioxidants from plants as well as
extract precipitation with or without the use of a
carrier material in one-step. This process has been
called OEPO for Organic solvent Extraction and
Particle formation On-line. Using this process, dif-
ferent products (precipitated extract, co-precipitated
extract or encapsulated extract in suspension) with
a very low residual organic solvent concentration
(< 50 ppm) can be obtained directly from plant
materials, employing supercritical CO2 as the anti-
solvent for organic solvent elimination. The OEPO
process consists of hyphenated Pressurized Liquid
Extrac tion (PLE)-Supercritical Anti Solvent (SAS)
precipitation, PLE-SAS co-precipitation and PLE-
Supercritical Fluid Extraction of Emulsions (SFEE).
The OEPO processes were successfully developed
using Brazilian ginseng roots (Pfaffia glomerata) as
a model case.
POSTERS 369
b) A process for the one-step production of emulsions
containing essential oils from saponin-rich pressur-
ized aqueous plant extracts was developed. Named
by our research group as Emulsion from Pressurized
Liquid Extraction (EPLE), the feasibility of this pro-
cess was demonstrated under optimal PLE condi-
tions (12 MPa), including a temperature of 393 K
(120 ºC) and 10 min of static time, using Brazilian
ginseng roots as the source of the saponin-rich ex-
tract, water as the extracting solvent and clove
essential oil as the model dispersed phase.
Therefore, it seems that the best route for the use of
the Brazilian ginseng roots is the co-production of an ex-
tract rich in beta-ecdysone (antioxidant compound), an
extract rich in compounds with surfactant properties and
hydrolysates rich in fermentable sugars. To use the Bra-
zilian Ginseng aerial parts, a similar approach is under
evaluation. After sub/supercritical water hydrolysis of both
raw materials solid residues are formed; accordingly, one
possible conversion process is the evaluation is the pro-
duction of synthetic natural gas (SNG) through supercritical
water gasification. In a broad sense, we also are concerned
with the integration of the proposed Brazilian ginseng
biorefinery to the sugarcane industry.
ACKNOWLEDGMENTS
FAPESP (2010/16485-5; 2012/19304-7; 2012/10685-8) and CNPq.
371
UTILIzATION OF CARBON DIOxIDE IN ThE ALGAL BIOREFINERy
Lindsay soh Department of Chemical and Biomolecular Engineering,
Lafayette College; Easton, PA, USA;
Email: [email protected]
Julie B. ZimmermanDepartment of Chemical and Environmental Engineering,
Yale University;New Haven, CT, USA
School of Forestry and Environmental Studies, Yale University;
New Haven, CT, USA
The imminence of peak oil has implications not only for
the security of our energy future, but also our dependence
on petrochemicals. The use of petroleum as a feedstock
for the production of fuels, plastics, solvents, and other
commodities is rampant and vital in our society. The de-
creasing supply of petroleum requires the need for renew-
able, alternative feedstocks for the production of fuels and
petrochemicals. Due to their fast growth, efficient use of
sunlight, and ability to be grown in varied environments,
microalgae have sparked great interest in terms of their
viability to as a renewable feedstock.
When considering algae as a potential feedstock,
the chemical fractions that are present must be evaluated,
processed, and utilized effectively. In this work, cultivation
of different microalgae species under varied growth con-
ditions was undertaken in order to characterize differenc-
es in biomass, lipid, protein, and starch productivity. The
results were used to inform a combinatorial life cycle as-
372 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
sessment, which highlights the need and ability to opti-
mize and tailor algal species and cultivation conditions
for a specific endpoint. Additionally, efficient processing
must be developed in order to harvest, separate, and con-
vert the different chemical fractions efficiently.
Within this context, supercritical carbon dioxide
(scCO2), a green solvent, has great potential towards the
efficient processing of algal biomass as a whole. Not only
is scCO2 considered green compared to other solvents, but
it also has selective and tunable solvent properties and is
easy to separate from end-products. In this work the use
of scCO2 for the efficient extraction and conversion of algal
lipids into biodiesel is explored with further implications
for processing within the context of a biorefinery.
scCO2 was shown to be an effective solvent for the
selective extraction of lipids from algal biomass. The se-
lectivity of scCO2 can be further exploited in order to har-
vest other value-added co-products such as carotenoids
or phospholipids. As a result of the clean extraction pro-
cess, the remaining biomass can be utilized for further
processing to harvest other products such as protein or
starch for a variety of applications such as animal feed,
further fuel production, or even the production of high
value commodities.
While the lipid fraction may have valuable use as
a chemical feedstock, its utilization in the production of
fuels is of great interest to create direct, drop-in replace-
ments for our current requirements. The further use of
dense CO2 as a medium for conversion of lipids into bio-
diesel was also researched. In combination with a het-
erogeneous catalyst, the successful transesterification of
triglycerides into fatty acid methyl esters was shown using
CO2 and methanol. In addition to aiding in the successful
conversion of triglycerides into biodiesel, the process offers
POSTERS 373
benefits in terms of selectivity during conversion. Develop-
ment of downstream technologies and intelligent process-
ing of biomass are necessary to for the viable, economical,
and sustainable use of algae as a renewable feedstock.
EqUILIBRIUM PARTITION OF SOLUTES BETwEEN SUPERCRITICAL CARBON DIOxIDE AND VEGETABLE SUBSTRATES
375
EqUILIBRIUM PARTITION OF SOLUTES BETwEEN SUPERCRITICAL CARBON DIOxIDE AND VEGETABLE SUBSTRATES
freddy A. urrego, José M. del valleFraunhofer Chile Research;
Avenida Mariano Sánchez Fontecilla 310, Piso 14, Las Condes, 7550296, Santiago de Chile, Región Metropolitana, Chile;
E-mail: [email protected]
The equilibrium partition of an extractable solute between
a solid (vegetable matrix) and a solvent [supercritical CO2
(scCO2)] is one of the limiting factors to the mass transfer
in the extraction with supercritical fluids (EFS). By study-
ing how this process works, one may enhance the preci-
sion and adaptability of mathematical models applied to
the EFS, making them more reliable tools in the simulation
of industrial-scale applications based on laboratory- or
pilot-plant-scale extraction results. We developed two ex-
perimental methodologies to measure the equilibrium par-
tition, and studied different solute-vegetable matrix systems
(oil-prepressed rapeseed, capsanthin-extruded + milled
red pepper, and lycopene-extruded + milled tomato). The
first methodology intersperses equilibration (by continu-
ous recirculation of scCO2 through a cell containing the
vegetable matrix) and extraction steps (mainly a static
methodology), it was applied to all the systems previous-
ly mentioned. The second methodology is based on chro-
matographic principles, where solute diluted in scCO2 is
continuously injected to a column packed with complete-
ly scCO2-extracted substrate, and isotherm/isobar curves
are calculated from dilution profiles read at the exit of the
column with a UV/Vis detector (dynamic methodology), it
376 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
was only applied to the lycopene-extruded + milled to-
mato system. The operation conditions were between 40-
67 °C and 22-28 MPa. Different mathematical functions
(Langmuir, Freundlich, Sip’s) were studied, and after mod-
ification and adaptation of the Sip’s isotherm, authors pro-
posed a new isotherm/isobar function. The oil-prepressed
rapeseed system was best-fitted with the del Valle-Urrego
function, whereas the capsanthin-extruded + milled red
pepper, and lycopene-extruded + milled tomato systems
were best-fitted with the Freundlich function. Based on
the results obtained with the mainly static methodology,
its results are considered closer to the physical reality, and
are therefore used as a comparison base. The dynamic
methodology proved to be inadequate to the studied sys-
tem, because lycopene was not so strongly re-adsorbed
onto the vegetable matrix, which led to an isotherm/iso-
bar curve with almost no affinity of lycopene for the solid
substrate. From these studies authors concluded that it is
necessary to measure and model isotherm/isobar curves
in order to improve the precision of mathematical models,
and furthermore, to count on calculated parameters values
that are more related to the physical reality.
ThE INTENSIFICATION OF ThE PROCESS SAPONIN ExTRACTION FROM BRAzILIAN GINSENG (pfAffiA gLoMERATA) USING ULTRASOUND AND hyPhENIzED PROCESSES FOR INTEGRAL PLANT USE
377
ThE INTENSIFICATION OF ThE PROCESS SAPONIN ExTRACTION FROM BRAzILIAN GINSENG (pfAffiA gLoMERATA) USING ULTRASOUND AND hyPhENIzED PROCESSES FOR INTEGRAL PLANT USE
Renata vardanega, Diego T. santos*, M. Angela A. Meireles
LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas);
R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]
*Industrial Energy Systems Laboratory (LENI), Swiss Federal Institute of Technology Lausanne (EPFL);
Station 9, CH-1015, Lausanne, Switzerland
Until recently, the biorefinery concept has been explored
as a possibility for sustainable processing with the reduced
consumption of energy from fossil fuels. The term biorefin-
ery is applied to the integral use of biomass for the pro-
duction of high-added-value products with minimal residue
generation using sustainable technologies, such as sub-
and supercritical fluids. Sub- and supercritical waters have
several application possibilities, ranging from extraction
to reactions, because they can act as both a benign solvent
and catalyst. Sub- and supercritical waters also can be
used to extract substances that cannot be obtained under
normal temperature and pressure conditions; additional-
ly, these solvents decompose natural biopolymers (cellu-
lose, protein, starch) to produce valuable compounds. To
increase the revenues from a given raw material, coproducts
in the form of valuable phytochemicals can be extracted
prior to performing hydrolysis either at the biorefinery site
or at a site of close proximity. Brazilian ginseng (Pfaffia
glomerata) is a commercialized substitute for ginseng
378 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
(Panax) due to its similar morphology and therapeutic ef-
fects. This plant has a large content of saponins, which
can be used as a natural surfactant. Moreover, the residue
from the extraction process is a good source of polysac-
charides. Therefore, this residue can be used to produce
several molecules, among them, second-generation eth-
anol. Considering the potential of this raw material and
the new trends in terms of the development of green tech-
nologies for the production of different products from the
same raw material, the possibility of the integral use of
Brazilian ginseng is very promising. Pressurized fluid tech-
nologies have become very interesting options and are the
focus of this research. First, we intend to develop an in-
tensified method that includes the use of sequential ex-
tractions to obtain distinct products of high-added-value
in each step, namely, extractions of saponins followed by
residue hydrolysis to produce fermentable sugars. After,
using the commercial software SuperPro Designer, the eco-
nomic viability of the process will be evaluated, and the
process will be simulated using ultrasound to increase
the yield of extraction and, thus, the productivity of the
process. Additionally, the possibility of coupling a purifi-
cation process, such as supercritical anti-solvent extrac-
tion, will be evaluated; the aim is to obtain high-quality
extracts using fewer steps than conventional processes.
Some preliminary results have shown that it is possible to
obtain extracts that are rich in bioactive compounds and
that possess emulsification properties from both the roots
and aerial parts of Brazilian ginseng by applying different
processing conditions in terms of the type of solvent used
and the processing temperature. Moreover, we have iden-
tified that it is possible to obtain simple sugars by hydrolyz-
ing the residue from the extraction process of the Brazilian
ginseng roots. Additionally, collaborative works have been
POSTERS 379
developed with colleagues on studies of the hydrolysis of
agricultural and food residues for the production of simple
sugars using sub- and supercritical water assisted by su-
percritical CO2. The hydrolysates obtained can be convert-
ed into second-generation bioethanol by fermentation.
ACKNOWLEDGEMENTS
The authors acknowledge the financial support from CAPES (DEA/FEA/
PROEX); partial support from FAPESP (2009/17234-9 and 2012/10685-8)
is also acknowledged. R. Vardanega thanks CNPq (140282/2013-0) for the
Ph.D. assistantship. M. A. A. Meireles thanks CNPq for the productivity
grant (302778/2007-1).
SFE TEChNOLOGy FOR POORLy DEFINED OLIGOMERIC MIxTURES
381
SFE TEChNOLOGy FOR POORLy DEFINED OLIGOMERIC MIxTURES
Julian velez, David f. Esguerra, Mark c. ThiesDepartment of Chemical and Biomolecular Engineering,
Center for Advanced Engineering Fibers and Films, Clemson University;
Clemson, SC 29634, USA; E-mail: [email protected]
Our research is focused on the use of supercritical (SC)
fluids to fractionate and characterize oligomeric carbona-
ceous pitches, potential precursors for advanced carbon
materials. In particular, we are performing semi-continuous
SC extraction experiments, investigating both SC toluene
and SC toluene/N-methyl-2-pyrrolidone (NMP) mixtures
as extractive solvents for fractionating a catalytically pro-
duced pyrene pitch into its constituent oligomers. Although
neat supercritical toluene (Tc = 318.6 °C; Pc = 41.1 bar)
has been shown to be an effective solvent for the recovery
of both monomer and dimer species in high purities, higher-
oligomer solubilities in toluene are notoriously low. The
addition of NMP as a co-solvent enhances oligomeric sol-
ubilities in the extractive, supercritical-solvent phase by
a factor of 3, making possible the recovery of trimer and
higher oligomers. In addition, it also suppresses the un-
desired, AlCl3-aided reactions that occur in the column
between the pyrene oligomers and toluene by forming
Lewis acid-base complexes with the AlCl3 catalyst. A su-
percritical co-solvent mixture consisting of 15 mol % NMP
in supercritical toluene was found to be an effective sol-
vent system for recovering pyrene dimer and trimer cuts
at purities exceeding 99%. These cuts exhibit dramatically
382 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
ThE INFLUENCE OF BED GEOMETRy ON ThE KINETICS OF ThE ExTRACTION OF VEGETAL COMPOUNDS WITh SUPERCRITICAL CO2 AND BIOMASS hyDROLySIS
different properties from the starting mixture once they
are isolated: for instance, the trimer fraction is found to
form a liquid-crystalline phase (i.e., mesophase) which is
not observed in either the starting mixture or the dimer
fraction.
A significant advantage of the use of SC extraction
technology in this work is that the high-purity pitch oligo-
mers isolated via SC extraction can serve as excellent
feedstocks for a variety of analytical characterization tech-
niques. For example, molecular-structure information on
the individual species comprising both the starting pitch
and the oligomeric cuts is obtained when these high-pu-
rity fractions are further fractionated by liquid chromatog-
raphy methods (e.g., GPC, HPLC) and/or analyzed with
techniques such as MALDI Mass Spectrometry and UV-Vis
and Fluorescence spectroscopy, etc. By using such a se-
quential separation technique (i.e., SC extraction followed
by analytical separation), the species comprising the pyrene
monomer and dimer fractions have been unambiguously
identified and their concentrations in the starting mate-
rial determined. These results show the potential of SC
fluid extraction technology for the molecular characteri-
zation and quantification of poorly defined, oligomeric and
polymeric mixtures, with applications in both biomass
and heavy fossil fuel conversion.
383
ThE INFLUENCE OF BED GEOMETRy ON ThE KINETICS OF ThE ExTRACTION OF VEGETAL COMPOUNDS WITh SUPERCRITICAL CO2 AND BIOMASS hyDROLySIS
giovani L. Zabot, Moyses n. Moraes, M. Angela A. Meireles
LASEFI/DEA/FEA (School of Food Engineering), UNICAMP (University of Campinas);
R. Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; E-mail: [email protected]
Natural substances extracted from plants present partic-
ular properties that are distinct from the properties of syn-
thetic substances and are useful in the formulation of
bioproducts, as well as in the pharmaceutical field. Novel
extraction techniques, such as the use of supercritical flu-
ids, are acquiring notoriety by providing the selective ex-
traction of bioactive compounds with high quality. In the
field of supercritical technology, investigations are per-
formed to increase the quantitative and qualitative yield
by changing the processing conditions (i.e., pressure, tem-
perature). However, it is necessary to discriminate further
the influence of other variables, such as the bed geometry.
Thus, the aim of this work is to evaluate the use of super-
critical CO2 extraction from the technical and economic
perspectives in obtaining compounds from clove and rose-
mary by using laboratory equipment that possesses 2
one-liter extractors with different height (HB) to bed diam-
eter (DB) ratios. The first and second steps of the thesis
work consisted of the assembly of this SFE-2×1L equip-
ment and in the characterization of the raw materials,
respectively. The third step was the evaluation of the tem-
perature profiles inside the beds, with the goal of selecting
the time for static process and defining the external con-
384 SFE 2013 | WORKShOP ON SUPERCRITICAL FLUIDS AND ENERGy
ditions for the extractor temperatures. The fourth step was
to compare the kinetic parameters obtained by adjusting
the extraction curves for both geometries (E-1: HB/D
B = 7.1;
E-2: HB/D
B = 2.7). Two criteria for scale-up were used. The
first criterion consisted of maintaining equal interstitial
solvent velocities in both geometries, which was not suit-
able for the process. The second consisted of maintaining
constant mass of solvent to mass of feed ratios (S/F) and
extraction times. This criterion was appropriate for this
process due to the similar mass transfer rates used in com-
parison to the commercial Spe-ed equipment (Applied Sep-
arations, 7071, Allentown, USA), which has a 0.1 L extractor
(E-3; HB/D
B = 3.9). Nonetheless, the bed E-2 presented
global yields slightly superior in comparison to E-1, main-
ly due to the excessive compaction observed in E-1. This
behavior was even more pronounced when rosemary was
used. As Laurent et al. [1] reported for the decaffeination
of coffee beans with a particle size of approximately 7 mm,
large HB/D
B ratios (approximately 9) should be used. How-
ever, for smaller particles in the range of 0.4-0.8 mm, which
tend to swell, the HB/D
B ratio should be 3. Using this in-
formation in our study, in which the particle average sizes
were 0.76 mm and 0.66 mm for clove and rosemary, re-
spectively, we conclude that the yield in E-1 (HB/D
B = 7.1)
was influenced by significant compaction and CO2 chan-
neling, which resulted in large axial dispersions of the
solvent-solute. These phenomena were most likely small
in E-2 (HB/D
B = 2.7). The selection of either E-2 or E-1 as
the convenient extractor also depends on studies of the
economic feasibility of the process, because low HB/D
B
ratios influence the construction costs of the extractors.
Thus, in the next step, the cost of manufacturing will be
simulated at different scales and geometries, including a
continuous operation mode. Further, process integration
POSTERS 385
is a recent trend that displays several applications in the
supercritical technology field. In this sense, the biomass
from extraction will be used to hydrolyze the lignocellu-
losic material, with the objective of obtaining high-add-
ed-value substances.
ACKNOWLEDGEMENTS
The authors acknowledge the financial support from CAPES (DEA/FEA/
PROEX); partial support from FAPESP (2009/17234-9 and 2012/10685-8)
is also acknowledged. G. L. Zabot thanks FAPESP (2011/23665-2) and M.
N. Moraes thanks CAPES for the Ph.D. assistantships. M. A. A. Meireles
thanks CNPq for the productivity grant (302778/2007-1).
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