micro process engineering
TRANSCRIPT
Micro Process Engineering
Edited by
Norbert Kockmann
Hessel, V., Renken, A., Schouten, J.C., Yoshida, J. (eds.)
Micro Process EngineeringA Comprehensive Handbook
2009
Print ISBN: 978-3-527-31550-5; also available in electronic formats
Saile, V., Wallrabe, U., Tabata, O., Korvink, J.G. (eds.)
LIGA and its Applications
2009
Print ISBN: 978-3-527-31698-4; also available in electronic formats
Hierold, C. (ed.)
Carbon Nanotube DevicesProperties, Modeling, Integration and Applications
2008
Print ISBN: 978-3-527-31720-2; also available in electronic formats
Bechtold, T., Schrag, G., Feng, L. (eds.)
System-level Modeling of MEMS
2013
Print ISBN: 978-3-527-31903-9; also available in electronic formats
Korvink, J.G., Smith, P.J., Shin, D. (eds.)
Inkjet-based Micromanufacturing
2012
Print ISBN: 978-3-527-31904-6; also available in electronic formats
Baltes, H., Brand, O., Fedder, G.K., Hierold, C., Korvink, J.G., Tabata, O. (eds.)
Enabling Technologies for MEMS and NanodevicesAdvanced Micro and Nanosystems
2004
Print ISBN: 978-3-527-33498-8; also available in electronic formats
Baltes, H., Brand, O., Fedder, G.K., Hierold, C., Korvink, J.G., Tabata, O. (eds.)
Enabling Technologies for MEMS and NanodevicesAdvanced Micro and Nanosystems
2004
Print ISBN: 978-3-527-33498-8; also available in electronic formats
Brand, O., Fedder, G.K. (eds.)
CMOS-MEMS
2013
Print ISBN: 978-3-527-33499-5; also available in electronic formats
Tabata, O., Tsuchiya, T. (eds.)
Reliability of MEMSTesting of Materials and Devices
2008
Print ISBN: 978-3-527-33501-5; also available in electronic formats
Iannacci, J.
Practical Guide to RF-MEMS
2013
Print ISBN: 978-3-527-33564-0; also available in electronic formats
Related Titles
Micro Process Engineering
Fundamentals, Devices, Fabrication, and Applications
Edited byNorbert Kockmann
Volume Editor
Dr.-Ing. Norbert KockmannUniversität Freiburg, IMTEKLS f. Konstr. v. MikrosystemenGeorges-Köhler-Allee 10279110 FreiburgGermany
Series Editors
Prof. Dr. Oliver BrandSchool of Electrical andComputer EngineeringGeorgia Institute of TechnologyAtlanta, GA 30332-0250USA
Prof. Dr. Gary K. FedderECE Department &The Robotics InstituteCarnegie Mellon UniversityPittsburgh,PA 15213-3890USA
Prof. Dr. ChristoferHieroldChair of Micro and NanosystemsETH ZürichETH-Zentrum, CLA H9Tannenstr. 38092 ZürichSwitzerland
Prof. Dr. Jan G. KorvinkIMTEK-Institut fürMikrosystemtechnikUniversität FreiburgGeorges-Köhler-Allee103/03.03379110 FreiburgGermany
Prof. Dr. Osamu TabataDepartment of MechanicalEngineeringFaculty of EngineeringKyoto UniversityYoshida Honmachi,Sakyo-kuKyoto 606-8501Japan
Cover:
Top left: mounting a chemical reactor with microstructured elements (Dr. Schirrmeister, Chapter 7; courtesy of Uhde GmbH and Degussa AG, Germany)Bottom right: mixing of aqueous solutions with Bromothymol Blue pH-indicator (Dr. Kockmann, Germany, Chapter 3)
First Edition 2006
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Besides the development of new devices the main goal of engineering activitiesis to achieve a high performance in technical systems with low effort for opti-mized processes and products. An incredible performance increase wasachieved in communication and information technology by the miniaturizationof electronic equipment down to the nanometer scale during the last decades.Moore’s law of doubling the number of circuits in electronic devices in 18months by miniaturization still holds since decades and is expected to last.
Process technology is a wide field where small processes down to the molecularscale happen in devices having a length of several meters. The scale-up of chemicalproduction or power plants has led to high energy efficiencies and affordable con-sumer products. Around 1920, cryogenic air separation units produced an amountof about 1.3 t/h oxygen with 98–99% purity. 30 years later, the largest air separationunits delivered about 5.2 t/h oxygen with 99% purity. Nowadays, the largest air sep-aration units are supplying large customers with about 65 t/h oxygen with 99.5%purity and higher. As the throughput increases, the specific energy consumptiondecreases from about 1.5 kW/kg oxygen to about 0.4 kW/kg oxygen. Besides thedevelopment of large units, the consumer specific supply was also addressed bysmall and adjusted plants for flexible production satisfying the costumer’s de-mand. Additionally, some branches of the chemical industry are not subjectedto the economy of scale like the pharmaceutical industry or fine chemicals; flexibil-ity as well as the product price and quality are the important factors.
The combination of process engineering and micro system engineering withthe design, fabrication, and integration of functional microstructures is one ofthe most promising research and development areas of the last two decades.This is reflected in the publishing of scientific journals like “Sensors and Actua-tors” (since 1981) as well as in the growing field of international conferenceslike �TAS (Micro Total Analysis Systems, since 1994), the IMRET (InternationalConference on Micro Reaction Technology by AIChE and DECHEMA, since1997), or the ICMM (International Conference on Micro and Mini Channels byASME, since 2003). This can also be seen in the growing industrial activitiesusing microstructured equipment in process development and production ofchemicals. Some activities can be summarized under the concept of process in-tensification, such as compact heat exchangers or structured packing in separa-tion columns for intensified heat and mass transfer. With characteristic lengthsof the devices in the size of boundary layers, the transfer processes can be en-
V
Preface
Micro Process Engineering. Edited by N. KockmannCopyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 978-3-527-33500-8
hanced and controlled in the desired way. Other activities include modular plat-forms and entire chemical plants consisting of several microstructure elementsand devices, mainly for laboratory and process development.
This book on micro process engineering is divided into four sections: funda-mentals (Chapter 1 to 6), the design and system integration (Chapter 7 to 9),fabrication technologies and materials (Chapter 10 to 12), and, finally, the appli-cations of microstructured devices and systems (Chapter 13 to 16). Each chapterhas review character and stands on its own, but is also integrated into the wholebook. A common nomenclature and index will help the orientation of the read-er. In Chapter 1 to 6 the fundamentals and tools of process engineering are pre-sented with single-phase and multiphase fluid flow, heat and mass transfer aswell as the treatment of chemical reactions following the concept of unit opera-tions. The equipment and process design is organized by project managementmethods and assisted by modeling and simulation as well as the integration ofsensors and analytical equipment, described in Chapter 7, 8, and 9. The broadfabrication variety of microstructured devices for micro process engineering isillustrated in Chapter 10, 11, and 12 grouped according the materials metal,polymers, silicon, glass, and ceramics. Some typical examples of microstruc-tured devices illustrate the various fabrication methods. Even more examplesare given in Chapter 13 to 15 with industrial applications in Europe, Japan andthe US. Last but not least Chapter 16 emphasizes the application of microstruc-tured devices in education and laboratory research work. This gives students adeeper insight into the complex behavior of chemical plants and will lead to amore sophisticated view of continuous flow processing in education, laboratoryexperiments, and chemical synthesis.
The aim of this book is the comprehensive description of actual knowledgeand competence for microfluidic and chemical process fundamentals, designrules, related fabrication technology, as well as an overview of actual and futureapplications. This work is located at the boundary of at least two different disci-plines, trying to collect and unify some of the special knowledge from differentareas, driven by the hope that innovation happens at the interfaces between thedisciplines. From this, the team of authors of various engineers, physicists andchemists, from universities, research institutes, and industry in different coun-tries contributes an embracing part of detailed know-how about processes inand applications of microstructures. I hope that this knowledge will help to lookout of the box to other related areas of chemical engineering, micro system en-gineering and to other engineering, physical, chemical, or biological areas.
Finally, I want to thank all the contributors for their enduring work, besidestheir actual work and activities. I hope that this enthusiasm can be readthroughout the book, will spread further on to the readers and will help to en-large the knowledge and activities on this new and gap-filling area of micro pro-cess engineering.
Norbert KockmannVolume EditorNovember 2005
PrefaceVI
We hereby present the fifth volume of Advanced Micro & Nanosystems (AMN),entitled Micro Process Engineering.
Usually, when engineering devices get smaller, we expect higher speeds, moreaccuracy, or less power consumption, but typically we do not associate smaller de-vices to successfully compete with larger ones when it comes to material through-put. Not so in micro process engineering. This research area has quietly grown inthe flanks, and promises to become one of the most profitable areas in microtech-nology. Why is this so? It turns out that micro process engineering targets themore efficient manufacture of chemical substances, no less than miniaturizedchemical factories that match the throughput of their macroscopic counterparts.
The volume editor, Dr. Norbert Kockmann, has assembled a notable interna-tional authors hip to bring to us the state of the art in this very exciting applica-tion area. At the microscale, many physical and chemical effects have to be re-evaluated as they apply to chemical engineering manufacturing processes, andin this volume six chapters guide us through the most important fundamentalconcepts. The revised theory implies the need for new design methods, and sothree chapters consider simulation, modelling, and system design. Device fabri-cation sets specific challenges, for all resulting production surfaces must bechemically and thermally resistant, and must target high throughput of liquidsand gases. Finally, because micro process engineering is driven by its excitingapplications, four chapters cover the most important topics from a completelyinternational perspective.
We are happy to report here that the decision to produce topical volumes such asCMOS-MEMS or Microengineering of Metals and Ceramics is finding tremendousacceptance with our readers and hence we will continue to plan further relevanttopics from either an application area or a specific manufacturing technology.
Looking ahead, we hope to welcome you back, dear reader, to the upcomingsixth member of the AMN series, in which we take a close look at the fascinat-ing field of LIGA and its application.
Oliver Brand, Gary K. Fedder, Christofer Hierold, Jan G. Korvink,and Osamu TabataSeries EditorsOctober 2005Atlanta, Pittsburgh, Zurich, Freiburg and Kyoto
VII
Foreword
Micro Process Engineering. Edited by N. KockmannCopyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 978-3-527-33500-8
Preface V
Foreword VII
List of Contributors XI
Nomenclature XV
1 Process Engineering Methods and Microsystem Technology 1Norbert Kockmann
2 Momentum and Heat Transfer in Microsized Devices 47Heinz Herwig
3 Transport Processes and Exchange Equipment 71Norbert Kockmann
4 Multiphase Flow, Evaporation, and Condensation at the Microscale 115Michael K. Jensen, Yoav Peles, Theodorian Borca-Tasciuc, andSatish G. Kandlikar
5 Generation and Multiphase Flow of Emulsions in Microchannels 149Isao Kobayashi and Mitsutoshi Nakajima
6 Chemical Reactions in Continuous-flow Microstructured Reactors 173Albert Renken and Lioubov Kiwi-Minsker
7 Design Process and Project Management 203Steffen Schirrmeister, Jürgen J. Brandner, and Norbert Kockmann
8 Simulation and Analytical Modeling for Microreactor Design 235Osamu Tonomura
IX
Contents
Micro Process Engineering. Edited by N. KockmannCopyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 978-3-527-33500-8
9 Integration of Sensors and Process-analytical Techniques 249Stefan Löbbecke
10 Microfabrication in Metals and Polymers 267Jürgen J. Brandner, Thomas Gietzelt, Torsten Henning, Manfred Kraut,Holger Mortiz, and Wilhelm Pfleging
11 Silicon Microfabrication for Microfluidics 321Frank Goldschmidtböing, Michael Engler, and Alexander Doll
12 Microfabrication in Ceramics and Glass 353Regina Knitter and Thomas R. Dietrich
13 Industrial Applications of Microchannel Process Technologyin the United States 387Daniel R. Palo, Victoria S. Stenkamp, Robert A. Dagle, andGoran N. Jovanovic
14 Industrial Applications in Europe 415Thomas Bayer and Markus Kinzl
15 Industrial Production Plants in Japan and Future Developments 439Jun-ichi Yoshida and Hideho Okamoto
16 Laboratory Applications of Microstructured Devicesin Student Education 463Walther Klemm, Bernd Ondruschka, Michael Köhler, and Mike Günther
Subject Index 497
ContentsX
XI
List of Contributors
Thomas BayerSiemens AGA&D SP Solutions Process IndustriesBusiness DevelopmentIndustriepark Höchst, Bldg. G 811D-65926 Frankfurt am MainGermany
Theodorian Borca-TasciucDepartment of Mechanical, Aerospaceand Nuclear EngineeringRensselaer Polytechnic Institute110 8th StreetTroy, NY 12180-3590USA
Jürgen J. BrandnerForschungszentrum KarlsruheInstitute for Micro Process Engineer-ing (IMVT)Hermann-von-Helmholtz-Platz 1D-76344 Eggenstein-LeopoldshafenGermany
Robert A. DaglePacific Northwest National Laboratory902 Battelle Blvd., K8-93Richland, WA 99354USA
Thomas R. DietrichMikroglas chemtech GmbHGalileo-Galilei-Str. 28D-55129 MainzGermany
Alexander DollLaboratory for Designof MicrosystemsDepartment of MicrosystemsEngineeringUniversity of Freiburg – IMTEKGeorges-Köhler-Allee 102D-79110 FreiburgGermany
Michael EnglerLaboratory for Designof MicrosystemsDepartment of MicrosystemsEngineeringUniversity of Freiburg – IMTEKGeorges-Köhler-Allee 102D-79110 FreiburgGermany
Thomas GietzeltForschungszentrum KarlsruheInstitute for Micro ProcessEngineering (IMVT)Hermann-von-Helmholtz-Platz 1D-76344 Eggenstein-LeopoldshafenGermany
Micro Process Engineering. Edited by N. KockmannCopyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 978-3-527-33500-8
List of ContributorsXII
Frank GoldschmidtböingLaboratory for Designof MicrosystemsDepartment of MicrosystemsEngineeringUniversity of Freiburg – IMTEKGeorges-Köhler-Allee 102D-79110 FreiburgGermany
Mike GüntherInstitute of PhysicsTechnical University IlmenauWeimarer Straße 32D-98684 IlmenauGermany
Torsten HenningForschungszentrum KarlsruheInstitute for Micro ProcessEngineering (IMVT)Hermann-von-Helmholtz-Platz 1D-76344 Eggenstein-LeopoldshafenGermany
Heinz HerwigTechnical ThermodynamicsTechnical UniversityHamburg-HarburgDenickestr. 17D-21073 HamburgGermany
Michael K. JensenDepartment of Mechanical, Aerospaceand Nuclear EngineeringRensselaer Polytechnic Institute110 8th StreetTroy, NY 12180-3590USA
Goran N. JovanovicDepartment of Chemical EngineeringOregon State University102 Gleeson HallCorvallis, OR 97331Microproducts Breakthrough InstituteCorvallis, OR 97330USA
Satish G. KandlikarDepartment of MechanicalEngineeringRochester Institute of TechnologyRochester, NY 14623-5604USA
Markus KinzlSiemens AGA&D SP Solutions Process IndustriesBusiness DevelopmentIndustriepark Höchst, Bldg. G 811D-65926 Frankfurt am MainGermany
Lioubov Kiwi-MinskerInstitute of Chemical Sciencesand EngineeringSwiss Federal Institute of Technology(EPFL)CH – LGRCCH-1015 LausanneSwitzerland
Walther KlemmInstitute of Technical Chemistryand Environmental ChemistryFriedrich Schiller University of JenaLessingstr. 12D-07743 JenaGermany
List of Contributors XIII
Regina KnitterForschungszentrum KarlsruheInstitute for MaterialScience III (IMF III)Hermann-von-Helmholtz-Platz 1D-76344 Eggenstein-LeopoldshafenGermany
Isao KobayashiFood Engineering DevisionNational Food Research InstituteKannondai 2-1-12, TsukubaIbaraki 305-8642Japan
Norbert KockmannLaboratory for Designof MicrosystemsDepartment of MicrosystemsEngineeringUniversity of Freiburg – IMTEKGeorges-Köhler-Allee 102D-79110 FreiburgGermany
Michael KöhlerInstitute of PhysicsTechnical University IlmenauWeimarer Straße 32D-98684 IlmenauGermany
Stefan LöbbeckeFraunhofer Institute for ChemicalTechnology (ICT)Joseph-von-Fraunhofer-Straße 7D-76327 PfinztalGermany
Manfred KrautForschungszentrum KarlsruheInstitute for Micro ProcessEngineering (IMVT)Hermann-von-Helmholtz-Platz 1D-76344 Eggenstein-LeopoldshafenGermany
Holger MoritzForschungszentrum KarlsruheInstitute for MicrostructureTechnology (IMT)Hermann-von-Helmholtz-Platz 1D-76344 Eggenstein-LeopoldshafenGermany
Mitsutoshi NakajimaFood Engineering DevisionNational Food Research InstituteKannondai 2-1-12, TsukubaIbaraki 305-8642Japan
Hideho OkamotoDepartment of Synthetic Chemistryand Biological EngineeringGraduate School of EngineeringKyoto UniversityKyoto 615-8510Japan
Bernd OndruschkaInstitute of Technical Chemistryand Environmental ChemistryFriedrich Schiller University of JenaLessingstr. 12D-07743 JenaGermany
List of ContributorsXIV
Daniel R. PaloPacific Northwest National Laboratory902 Battelle Blvd., K8-93Richland, WA 99354
Microproducts Breakthrough InstituteCorvallis, OR 97330USA
Yoav PelesDepartment of Mechanical, Aerospaceand Nuclear EngineeringRensselaer Polytechnic Institute110 8th StreetTroy, NY 12180-3590USA
Wilhelm PflegingForschungszentrum KarlsruheInstitute for MaterialScience I (IMF I)Hermann-von-Helmholtz-Platz 1D-76344 Eggenstein-LeopoldshafenGermany
Albert RenkenInstitute of Chemical Sciencesand EngineeringSwiss Federal Institute of Technology(EPFL)CH – LGRCCH-1015 LausanneSwitzerland
Steffen SchirrmeisterUhde GmbHFriedrich-Uhde-Str. 15D-44141 DortmundGermany
Victoria S. StenkampPacific Northwest National Laboratory902 Battelle Blvd., K6-28Richland, WA 99354USA
Osamu TonomuraDepartment of Chemical EngineeringKyoto UniversityKatsura Campus, Nishikyo-kuKyoto 615-8510Japan
Jun-ichi YoshidaDepartment of Synthetic Chemistryand Biological EngineeringGraduate School of EngineeringKyoto UniversityKyoto 615-8510Japan
List of main parameters
If not indicated in the text.
Name Unit Description
A m2 area or cross section
am2
stemperature conductivity a � �
�cp
b m geometrical factor, channel widthC – constantCi – ratio of heat capacity fluxes
cms
absolute velocity
ci – concentration of component i
cpkJ
kg Kisobaric specific heat capacity
cvkJ
kg Kisochoric specific heat capacity
Dm2
sdiffusion coefficient
D m diameter
dh m hydraulic diameter � 4AU
E J energy
eJ
kgspecific energy
F N forcef – probability distribution function
Gkg
m2smass velocity (US literature)
g m/s2 gravity constant
XV
Nomenclature
Micro Process Engineering. Edited by N. KockmannCopyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 978-3-527-33500-8
g m temperature jump coefficientH J enthalpyHi Pa Henry coefficient
hJ
kgspecific enthalpy
hLVJ
kglatent heat of vaporization
hW
m2Kheat transfer coefficient (US literature)
h m geometrical factor, heightI A electrical currentJ J/s general energy currentK – general coefficient
kW
m2Koverall heat transfer coefficient
kW
mKthermal conductivity (US literature)
k *) reaction rate constant, *) unit depends onreaction order
kMkgsPa
membrane conductivity
kJK
Boltzmann constant 1�380662� 10�23 JK
� �
L m lengthLij – general transport coefficientLp mol/s rate of productionl m length, characteristic
Mkg
kmolmolar mass
M� kg mass of an atom or moleculem kg massm – reaction order
�mkgs
mass flow
N – number
Ni – ratio of transferred heat to heat capacity,number of transfer units
n 1/s rotation speedn mol amount of substance�n mol/s molar flow rateP W power
p bar, Pa � Nm2
pressure
NomenclatureXVI
pi bar, Pa � Nm2
partial pressure
Q J � Nm � kg m2
s2 heat
�Q W � Js
heat flux
qJ
kgspecific heat
�qWm2 specific heat flux
R m radius
RJ
kg Kindividual gas constant � Rm
M
Rimolm3s
transformation rate
RmJ
kmol Kuniversal gas constant 8�314
kJkmol K
� �
RelVA
electrical resistance
r m location coordinate, radiusr 1/s reaction rate
SJK
entropy
S� – heat production potential
sJ
kg Kspecific entropy
T K temperature (Kelvin)t s timeU J inner energyU m circumference, perimeterU V electric voltage
uJ
kgspecific inner energy
ums
velocity in x-direction
V m3 volume�V m3/s volume flow rate
�ms
velocity in y-direction
�vms
vector of velocity
W J workWdiss J dissipation work
Nomenclature XVII
wms
velocity in z-direction
wJ
kgspecific work
X – general transport variableX – conversion�x m position vectorx m cartesian coordinatex – vapor quality or void fractionxi – liquid concentration of component iy m cartesian coordinateyi – vapor concentration of component iz m cartesian coordinate, main flow direction in a
channel
Greek letters
�W
m2Kheat transfer coefficient
� – mixing quality
�ms
mass transfer coefficient
� – Arrhenius number
�kg
m2smomentum transfer coefficient
�Nm
interfacial tension
�i – relative amount of substance, mole fraction
� m boundary layer thickness
�m2
s3 specific energy dissipation
� – porosity� – friction factor of channel fitting or installation� m slip length of rarefied gas flow
kgm s
� Nsm2
dynamic viscosity
– dimensionless temperature� deg contact angle� – heat exchanger efficiency� – isentropic exponent
m mean free path length
�W
mKheat conductivity
NomenclatureXVIII
�R – channel friction factor
� Pa s dynamic viscosity (US literature)
�m2
skinematic viscosity �
�
�i – stoichiometric coefficient�i Pa mole fraction acc. Raoult’s law
�kgm3
density � mV
� m diameter of an atom or molecule
�Nm
surface tension
��J
Ksdissipation function or local entropy production
� s space time
�N
m2shear stress
� – probability� – dispersion� 1/s angular velocity
Sub- and superscripts
�x vector description of x�x mean value of xx� dimensionless form of x
Dimensionless numbers of fluid mechanics, heat and mass transfer
Name Description
Bi � �l�
Biot number (�=�solid)
Bo � wlDax
Bodenstein number
Bo � q��
Ghfgboiling number (US literature)
Bo � WeFr� d2g�
�Bond number (US literature)
Ca � w�
capillary number
Nomenclature XIX
Co � 1� xx
� �0�8�V
�L
� �0�5
convection number
DaI � tr
�res1st Damköhler number
DaII � ks
kD� tr
tD2nd Damköhler number
Dn � ReDRc
� �1�2
Dean number
Ec � w2
cp�TEckert number
Eu � �p�w2
Euler number
Fo � atl2
Fourier number
Fr � w2
dgFroude number
Gr � gz�ps3�T
�2Grashoff number
Kn �
LKnudsen number
Le � aD
Lewis number
Ma � wc
Mach number
Ne � P�n3d5 Newton number
Nu � �l�
Nußelt number (�=�Fluid)
Pe � RePr � wla
Péclet number
Pr � �
aPrandtl number
Ra � GrPr Rayleigh number
Re � wl�
Reynolds number
Sc � LePr � �
DSchmidt number
NomenclatureXX
Sh � �lD
Sherwood number
We � w2d��
Weber number
� n2d3�
�
Mathematical operators
D substantial differential
d general differential
� partial differential
� delta, divergence, difference
� ��i
�
�x��
j�
�y��
k�
�zNabla operator
grad � � �� gradient of �
div �v � � �v divergence of �v
rot �v � �� �v rotation of �v
�� � �2�
�x2� �2�
�y2� �2�
�z2Laplace operator
Main conferences and their abbreviation
IMRET 1: W. Ehrfeld (Ed.), Microreaction Technology, Proc. of the 1st Int. Conf.on Microreaction Technology 1997, Springer, Berlin, 1998.
IMRET 2: Proc. of the 2nd Int. Conf. on Microreaction Technology, AIChE Na-tional Spring Meeting, New Orleans, 1998.
IMRET 3: W. Ehrfeld (Ed.), Microreaction Technology: Industrial Prospects, Proc.of the 3rd Int. Conf. on Microreaction Technology 1999, Frankfurt,Springer, Berlin, 2000.
IMRET 4: Microreaction Technology: Proc. of the 4th Int. Conf. on MicroreactionTechnology, AIChE National Spring Meeting, Atlanta, 2000.
IMRET 5: M. Matlosz, W. Ehrfeld, P. Baselt (Eds.), Microreaction Technology,Proc. of the 5th Int. Conf. on Microreaction Technology 2001, Straß-bourg, Springer, Berlin, 2002.
IMRET 6: P. Baselt, U. Eul, R. S. Wegeng, I. Rinard, B. Horch (Eds.), Proc. ofthe 6th Int. Conf. on Microreaction Technology, AIChE NationalSpring Meeting, New Orleans, 2002.
IMRET 7: A. Renken, M. Matlosz (Eds.), Proc. of the 7th Int. Conf. on Micro-reaction Technology 2003, Lausanne, 2003.
Nomenclature XXI
IMRET 8: Proc. of the 8th Int. Conf. on Microreaction Technology, AIChE Na-tional Spring Meeting, Atlanta, 2005.
ICMM2003: S.G. Kandlikar, ASME 1st Int. Conf. on Microchannels and Minichan-nels, Rochester NY, 2003.
ICMM2004: S.G. Kandlikar, ASME 2nd Int. Conf. on Microchannels and Mini-channels, Rochester NY, 2004.
ICMM2005: S.G. Kandlikar, M. Kawaji, ASME 3rd Int. Conf. on Microchannelsand Minichannels, Toronto, Canada, 2005.
NomenclatureXXII
Norbert Kockmann, Laboratory for Design of Microsystems, Department of MicrosystemEngineering (IMTEK), University of Freiburg, Germany
AbstractThe fundamentals of chemical engineering are presented with the aim of appli-cations in microsystem technology, microfluidics, and transport processes in mi-crostructures. After a general overview about both disciplines and commonareas the concept of unit operations is briefly introduced. The balance equationsare derived from statistical mechanics and applied to other relevant systems ofprocess engineering together with the kinetic description of main transfer pro-cesses. Engineering tools like dimensional analysis, order of magnitude estima-tions, or lumped element modeling are explained, which are very helpful fordealing with complex nonlinear systems. Concluding this chapter, the benefitsand limits of miniaturization of various unit operations and typical issues areexplained that might serve as a plentiful source for the future development.
KeywordsUnit operations, balance equations, transport equations, engineering modeling,scaling process
1.1 Introduction 21.2 Unit Operations and Beyond 51.3 Balances and Transport Equations 91.3.1 Statistical Mechanics and Boltzmann Equation 101.3.2 Macroscopic Balance Equations 131.3.3 The Mass Balance 141.3.4 The Species Equation 141.3.5 The Momentum Equation and Force Balance 151.3.6 The Energy Balance 161.3.7 The Entropy Equation and the Efficiency of a System 181.3.8 Elementary Transport Processes and their Description 19
1
1Process Engineering Methods and Microsystem Technology
Micro Process Engineering. Edited by N. KockmannCopyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 978-3-527-33500-8
1.3.9 Additional Remarks to Balance Equations 211.4 Calculation Methods and Simulation 211.4.1 Physical Variables and Dimensional Analysis 221.4.2 Similarity Laws and Scaling Laws 241.4.3 Order of Magnitude 241.4.4 Lumped Element Modeling 251.4.5 Numerical Simulation and Analytical Modeling 261.5 Miniaturization and its Application to Transport Processes 271.5.1 Length 271.5.2 Area 321.5.3 Volume 381.5.4 Other Topics 411.6 Conclusions and Outlook 42
References 42
1.1Introduction
Process technology and microsystem technology are both interdisciplinary engi-neering and natural science branches connecting physics, chemistry, biology, en-gineering arts, and management techniques to an enabling toolbox for variousapplications. Process engineering embraces orientating calculations for processand equipment design under general orientation, and system-orientated, cross-linked thinking. Process engineers are working in various areas ranging fromthe food industry through biotechnology to pharmaceutical products, from ana-lytical and laboratory equipment through energy conversion to industrial chem-istry for the production of millions of tons of chemicals [1, Chapter 1]. Chemicalprocess engineering covers not only the design and implementation of chemicalproduction and analytical processes but also deals with the equipment design,the appropriate materials, the fabrication, and operation of various chemicalproduction processes. The aims of process technology are the economical andsafe production of the desired products with the intended form and composi-tion.
Microsystem technology, coming from information technology and miniaturiza-tion of data-processing devices, has now entered many fields in our daily life. Sil-icon chips and sensors can be found in cars, washing machines or smart cardswith various functions. Besides the data-processing function, microsystems havetaken over other tasks like sensing and analyzing, actuating or controlling largersystems. Microsystem engineering comprises besides engineering skills like de-sign, simulation, or material knowledge also a deep physical and chemical knowl-edge for the fabrication and functional design issues. Also medical and biologicalskills are useful for the growing application fields for analysis, diagnostics, andtherapeutics. A good overview about the state-of-the-art in microsystem technology
1 Process Engineering Methods and Microsystem Technology2
is given in [2]. For the control and manipulation of still smaller systems, microsys-tem technology is a major link to nanotechnology [3, 4].
Figure 1.1 gives an impression of the wide field and complexity of both disci-plines, but also illustrates the multiple interfaces and common fields. The fruit-ful ideas from both sides may inspire the further development in both disci-plines and result in an enlargement of possibilities and applications for the in-novation across the borderlines.
Chemistry in miniaturized equipment is an emerging discipline coming to-gether from microsystem technology and from chemical engineering, but alsoan established discipline of chemical analytics. Starting at the end of the nine-teenth century a group of researchers at the University of Delft around Behrens[4a] and at the Technical University of Graz around Prof. Emich and Prof. Pregldeveloped the chemical analysis of very small amounts of reagents. In 1900Prof. Behrens wrote his book “Mikrochemische Technik” [4a] about micro chem-ical techniques. In 1911 Prof. Friedrich Emich published the textbook “Lehr-buch der Mikrochemie” [5] and Prof. Fritz Pregl was rewarded in 1923 by theNobel price for his fundamental work in microchemical analysis. In the middleof the last century in nuclear science small structures were developed for theseparation of isotopes, see [6]. From this work, among others, the LIGA technol-ogy emerges at German research institutes.
Dealing with very small geometrical structures is also a well-known area inprocess engineering. The adsorption technology and chemical reactions at cata-lytic surfaces are based on the flow and adhesion processes in nanoscale pores[7, Chapter 4]. Transformations and transfer processes on the molecular scaleare called “micro processes” in contrast to a “macro process” where convection
1.1 Introduction 3
Fig. 1.1 Disciplines of process engineering and microsystemtechnology, differing and common overlapping areas(middle column). The lists are not complete and the futurewill certainly bring new applications and new common fieldsand applications.
plays the major role. Some typical length scales for process technology, chemis-try and microtechnology are given in Fig. 1.2.
Figure 1.2 illustrates the different wording in process engineering, microsys-tem technology, and nanotechnology, especially the different meaning of “mi-cro”. The micropores in adsorption media are one characteristic example on thenanometer scale. Microstructured equipment has internal characteristic dimen-sions like channel diameter or gap height within the micrometer range. A cleardefinition of “micro” does not exist, but it is not necessarily required for all ap-plications and areas.
In the process industry, there are several applications of structures with typi-cal dimensions below 1 mm, like compact plate and fin heat exchangers orstructured packings in separation columns for enhanced heat and mass transfer.This is often summarized under the key word of process intensification. How-ever, the miniaturization of conventional technology is limited by two major re-strictions: the fabrication possibilities for the small structures at reasonablecosts and the increased fouling probability, the high danger of blocking, and to-tal failure of these structures. The first restriction has been widened with theenhanced fabrication possibilities, but the risk of fouling and blocking is stillthere and should not be underestimated.
The elementary setup of microstructured and conventional equipment is simi-lar and displayed in Fig. 1.3. Process plants consist of process units, whichthemselves are made of equipment like heat exchangers or vessels with internalstructures. The basic geometrical elements of the internal structures in conven-
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Fig. 1.2 Characteristic length of important processes andequipment in chemical engineering and microsystemtechnology. The top and bottom line indicate also thedifferent wording of micro processes in the two disciplines,adopted from [8].
tional technology are the tube, the plate, and the film, on or in which the trans-port processes and transformations happen. The layout of process equipmentand process steps follow this scheme from small elementary active areas (“mi-cro process”) over the process space of the device (“macro process”) to the bal-ancing of the complete process.
The parallel arrangement of microstructured channels or elements is calledinternal numbering-up, which is the most frequent way to increase the through-put of an apparatus. The parallelization of microstructured devices is called ex-ternal numbering-up, applied to bypass the flow distribution problems withinthe equipment. A relatively new concept is the equal-up concept, the paralleliza-tion of similar effects [8]. The numbering-up and equal-up concepts facilitatethe scale-up process from laboratory equipment to production equipment, butstill have their own problems of flow distribution in manifolds, see Chapter 8.
1.2Unit Operations and Beyond
The consecutive groups or steps in a process plant can frankly be named formany cases as� pretreatment or conditioning of the incoming substances,� transformation of the reagents in chemical, physical, or biological processes,� separation of the received components, and� purification and conditioning of the products, see Fig. 1.4.
The physical and chemical processes in the various steps may be the same or sim-ilar, like heat transfer or extraction. They are called unit operations that are playing a
1.2 Unit Operations and Beyond 5
Fig. 1.3 Setup of microstructured andconventional equipment from single micro-structures through combined elements to anentire plant. The principle of the active area
can be applied in both cases(Sources: * from [9]; + courtesy of FhG-ICT,Pfinztal, Germany; o courtesy of Linde AG,Wiesbaden, Germany).
major role in the research and development of process engineering. The unit op-erations can be combined and connected in different forms. The concept of unitoperation combines a macro process with the apparatus to a process unit. It allowsus to treat all micro processes within the process space in the same manner and toderive scientifically based design rules and calculation instructions. For an entireprocess plant the unit operations are combined and switched in a proper way andintegrated for efficient material and energy use. Besides the energy and mass flowintegration the appropriate process control and automation determines the eco-nomical performance and safety of the plant. This gives a very complex pictureof a chemical or process technology plant, which is illustrated in Fig. 1.4. For a prop-er design and operation of a plant, many disciplines have to work closely together.
The unit operations can be categorized into three major groups according theemployed physical effects and major driving forces for combination or separa-tion of substances: the mechanical, the electromagnetic, and the thermal unitoperations (molecular driving forces) see Table 1.1. This list does not claim tobe complete, especially the separation processes from analytics are only shownschematically. Probably in the next years further operations will be developedenabled by enhanced fabrication and integration possibilities. In adsorption ofspecies or membrane separation, chemical processes may also be involved formass-transfer processes in microstructures, see [11, Chapter 3]. The consequenttreatment of unit operations allows the methodological design with help of thefollowing principles. The principle of continuity of substances, phases, energyand momentum includes the preference of continuous processes opposite tobatch processes. The principle of balancing of the relevant transport processesgives the energy, momentum, and mass fluxes in differential or black-box form.The principle of scaling and similarity of processes gives a calculation tool fortransferring experimental, analytical, and numerical results to processes on dif-ferent scales with the help of dimensionless numbers and groups.
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Fig. 1.4 Main process steps in a chemical production plantwith pretreatment, conversion, separation, and purification ofthe products, adapted from [10]. The system integrationincludes the energy management, auxiliary media as well asinformation for the process control and automation.