nature of current biomass production
TRANSCRIPT
Roger Ruan, Ph.D.Yangtze Scholar Distinguished Guest Professor
Nanchang University and
Professor and DirectorCenter for Biorefining
Department of Bioproducts and Biosystems Engineering
Innovative Wastewater Biomass Production and Conversion Systems
Nature of Current Biomass Production
• Distributed production
• Transporting bulky or wet biomass from scattering production sites to a central processing facility has been a key barrier to biomass utilization
Cellulosic EthanolCellulosic Ethanol
•• 4040--50 million gallons/year cellulosic ethanol 50 million gallons/year cellulosic ethanol plants: cost over $300 million to build, need plants: cost over $300 million to build, need over 2,000 tons biomass per day over 2,000 tons biomass per day
•• Furthermore, compared with corn ethanol Furthermore, compared with corn ethanol production, additional processing costs are production, additional processing costs are needed to convert cellulosic feedstock to needed to convert cellulosic feedstock to fermentable sugars, which would raise fermentable sugars, which would raise feedstockfeedstock--associated costs to as high as 70associated costs to as high as 70––80% of the final product cost, in additional to 80% of the final product cost, in additional to other technical and management challenges.other technical and management challenges.
Gasification and Fischer–Tropsch Liquid Biofuels
•• 4040--50 million gallons/year liquid fuel plants: 50 million gallons/year liquid fuel plants: cost about $1 billion to build, need over 3,000cost about $1 billion to build, need over 3,000--4,000 tons biomass per day, and expensive to 4,000 tons biomass per day, and expensive to operate due to catalyst cost and safety issue operate due to catalyst cost and safety issue related to high pressure and high temperature related to high pressure and high temperature of the process, in additional other technical and of the process, in additional other technical and management challenges.management challenges.
Distributed Biomass Conversion Systems (DBCS) -A “Smaller” Solution
Conversion
Bale to Barrel DBCS
1,000lb, 100ft3
10lb/ft3
7,500,000BTU75,000BTU/ft3
One round hay balediameter = 5ftlength = 5ft
1.2 barrel500lb, 6.7ft3, 75lb/ft3
3,750,000BTU562,500BTU/ft3
1,500,000BTU
As fertilizer back to field for biomass production
Power for conversion
2,250,000BTU
Gas
Can be implemented on average size farms or small villages
Distributed Biomass Processing Scheme
Microwave Assisted Pyrolysis (MAP) System
Micorwave Pyrolysis of Aspen
Canola Seed Press Cake
Municipal Solid Wastes
MSW Pyrolysis Products
Algal Biomass Pyrolysis
Comparison of fossil oil and bio-oil from MAP of Chlorella sp. and fast pyrolysis of wood
Bio-oils
Properties Chlorella sp. Wooda Fossil oila
Elemental analysis (wt.%)
C 65.40 56.4 83.0-87.0
H 7.84 6.2 10.0-14.0
N 10.28 0.1 0.01-0.7
O 16.48b 37.3 0.05-1.5
HHV (MJ/kg) 30.7c 21 42
Density (kg/L) 0.98d 1.2 0.75-1.0
pH 7.0-9.5 2-3
Viscosity, at 40 oC (Pa s) 0.06 0.04-0.20 2-1000
Continuous microwave assisted pyrolysissystem development
Pilot MAP system video
MobileMicrowaveAssisted Biomass PyrolysisSystem
Advantages of MAP• Microwave heating is uniform and easy to control;
• It does not require high degree of feedstock grinding (e.g., large chunk of wood logs can be used) and can handle mixed feedstock (e.g., municipal solid wastes);
• The conversion products (pyrolytic gas and bio-oils) are cleaner than those from gasification and conventional pyrolysis because our process does not have to use biomass powder and does not require agitation and fluidization;
• The syngas produced has higher heating value since it is not diluted by the carrying gas for fluidizing the biomass materials;
• Exothermic reactions (chemical reaction that releases energy) can be maintained through careful control of the process parameters and therefore MAP is energy efficient; and
• Microwave heating is a mature technology and development of microwave heating system for biomass pyrolysis is of low cost.
• Scalable, portable, mobile – distributed conversion of biomass
Oxygen
Sludge incinera
tion
Sludge Sludge incineraincinera
tiontion
Wastewater
treatment
Harvested Algae
HarvesteHarvested Algaed Algae
Algae production system enclosed
in greenhouse
Cleaned water
Fertilizer
Bio-oil
in
in
out
out
out
in
Algae to FuelCoupling algae production with waste treatment is the way for algae based biofuel to succeed
Nutrients in waste water
CO2 in flu gas
Algae biomass
Algae culture
Clean Technologies
Why will micro-algae be an optimal renewable bio-energy resource?
Oil Starch &Protein
SolidResidue
BiodieselFeed
EthanolSyngasBio-oil
Ethanol
Why will micro-algae be an optimal renewable bio-energy resource?
• Microalgae are microscopic aquatic plants that carry out the same process and mechanism of photosynthesis as higher plants in converting sunlight, H2O + CO2 into biomass +O2:
H2O + CO2 + NH3 + P2O5 + Photons -> Biomass (CNxHyOz) + O2
• One main difference: microalgae grow in water, can’t get enough CO2
from air – require a source of CO2 (e.g. flue gas). Also, they grow very fast, require continuous hydraulic cultures and essentially daily harvesting.
Advantages of algae
• Much greater productivity than their terrestrial cousins
• Non-food resource
• Utilize non-productive land and saline water
• Can use waste CO2 streams
• Can be used to combined with wastewater treatment
• An algal biorefinery could produce oils, protein, and carbohydrates
• High oil content algae species: Above 50%, some as high as 75%.
Goal
Demonstrate an innovative continuous closed photobioreactor algae production system that simultaneously produces high lipid algae for biofuel production, and captures and recycles N and P, utilizes organic carbon in the wastewater and sequester CO2 from waste sludge incineration.
• Free water• Free nutrients• Free flue gas• Wastewater treatment
Remove N, P, CODReduce greenhouse gas emission
Advantages of Wastewater-based Algae System
Mixotrophy has the best growth rate
• Can use organic carbon and CO2 at the same time
• Growth rate is the sum of autotrophic and heterotrophic growth rate
• Can grow under sunlight during the day and dark during the night
• Photoautotrophy – relatively slow
• Heterotrophy – use sugar – too expensive
SMBREL
N
• 180 MGD municipal wastewater
• 1 MGD concentrated municipal wastewater (CMW)
St. Paul Wastewater Treatment Plant
Grit screen Primary settling tanks
Activated sludge process
Final settling tanks Disinfection
Sludge processing
Recycle stream
bacteria return
Sludge disposal
Centrate
Parameter Concentration (mg/L) Parameter Concentration (mg/L)
Soluble COD 2324 ± 40.1 PO43--P 212± 7.2
TOC 960±30.50 NH3-N 91±1.8
pH 6.31 ± 0.11 TKN 134± 6.8
NO3-N 0.35 ± 0.36 NO2-N <0.03
Total suspended solid 0.14±0.11
Zhou, W, et al. Bioresour. Technol. 102 (2011) 6909-6919
Characteristics of the Concentrated Municipal Wastewater (CMW)
Total Organic Caron Profile of the Concentrated Municipal Wastewater (CMW)
Organic carbon profile for CMW by GC-FID
Our Focus
• Local bioprospecting of algae for wastewater-based culturing system
• Mixotrophic and two-stage (mixotrophic/ heterotrophic then photoautotrophic) algae culturing system
• Greenhouse-based photobioreactor system for year-round continuous algae production in northern climates
• Screening Omega-3 unsaturated fatty acid to grow on swine manure wastewater for valuable animal feed production
• Harvesting and utilization
Sludge processing
“CENTRATE”nutrient rich liquid
from sludge
Greenhouse basedphotobioreactors
Sludgeincinerator
Boiler & steam turbine/generato
rElectricity
Water discharged to next treatment step or 2nd stage autotrophic growth
Algal biomass
Heat
Integration of Pilot-Scale Facility into Metro Plant Process Flow
Removal of phosphorus (P) and nitrogen (N) are seen as the drivers for adoption of this technology by most WWTPs.
Flue gas
• Screening algae species based on:– Grow mixotrophically in wastewater
– High biomass production
– High oil content
Algae Species Screening
½ medium ½ medium + ½ wastewater ¼ wastewater
Species/strain selection
Collection -> evaluation -> adaptation/acclimatation -> re-evaluation
Algae Species Screening
Algae Species Screening
Top-performing native microalgal strains grown well on CMW
Zhou, W, et al. Bioresour. Technol. 102 (2011) 6909-6919
Code Species Size(um) Maximal Growth
rate(d-1)
Biomass
productivity(mg L-1d-1)
Lipid
productivity(mg L-1d-1)
UM 221 heynigia. sp 6-9 0.431 210.4 50.8
UM 224 Chlorella. sp 6-10 0.455 231.4 77.5
UM 280 Auxenochlorella
protothecoides
6-9 0.492 268.8 77.7
UM 231 Chlorella. sp 7-9 0.391 179.2 41.7
UM 235 Chlorella. vulgaris 2-4 0.293 120.8 21.0
UM 281 Micractinium. sp 5-7 0.455 231.4 42.6
UM 258 Scenedesmus. sp 13-15 0.411 193.8 49.8
UM 259 Chlorella. vulgaris 3-5 0.367 162.5 36.9
UM 265 Hindakia sp 6-9 0.498 275.0 77.8
UM 268 Chlorella. sp 5-7 0.325 137.5 36.9
UM 269 Chlorella. sp 5-7 0.317 137.5 65.4
UM 270 Chlorella. sorokiniana 6-9 0.402 187.5 49.4
UM 253 Chlorella. sp 6-8 0.466 241.7 74.7
UM 271 Chlorella. sp 5-7 0.434 212.5 58.5
UM 273 Chlorella. sp 7-9 0.416 197.9 41.3
UM 277 Chlorella. sorokiniana 5-7 0.397 183.3 94.8
UM 284 Scenedesmus. sp 13-15 0.472 247.5 74.5
0.00
0.50
1.00
1.50
2.00
2.50
3.00
0 100 200 300 400
Tim e (h)
OD (680nm)
0.00
0.50
1.00
1.50
2.00
2.50
0 50 100 150 200
Tim e (h)
OD (680nm)
(a) indoor condition (b) greenhouse
UM 270 grows well in wastewater in indoor and greenhouse conditions with yield over 1.5 g/L/d
First stage Second stage Third stage
• First stage
• Mixotrophic /
Photoheterotrophic
• Second stage
• Transition period
• Third stage
• Photoautotrophic
0.5
0.7
0.9
1.1
1.3
1.5
1.7
1.9
2.1
1 2 3 4 5 6 7 8 9 10 11 12
Day
TVSS(g/L)
5% CO2
1% CO2
0% CO2
0
0.5
1
1.5
2
2.5
3
3.5
1 2 3 4 5 6 7 8 9 10 11 12Day
TVSS(g/L)
5% CO2
1% CO2
0% CO2
TVSS
0
0.5
1
1.5
22.5
3
3.5
4
4.5
1 2 3 4 5 6 7 8 9 10 11 12
Day
TVSS(g/L)
5% CO2
1% CO2
0% CO2
Low Light
Middle Light
High Light
Biomass Concentration
Two-stage Cultivation System
First stage : Heterotrophic cultivation mode dominated
Harvest: Self-sedimentation
Second stage : Photoautotrophic cultivation mode dominated
Grow algae on concentrated wastewater in
heterophyic/mixotrophicway in 3 layers bioreactor
1/3 volume of algae media harvested by self-sendimentation
Algae cultivation in autotrophic growth way for
treatment of whole recycled water using 3
photobioreactors
Recycled algae media for self-
sendimentationFreshwater
wastewater disposal after two-stage
cultivation
Water discharged for next step treatment
Semi-continuous cultivation with 1/3
harvest rate
BiodieselHarvested algal powerRefined Oil
Two-stage Cultivation Strategy for Wastewater Treatment and Biofuel Feedstock Production
Sparging with CO2/flue gas
Hydrothermal / pyrolysis refinery
process
Transesterification
Nutrient removal efficiency and biomass yield by two-stage strategy
Current Cultivation System
Combined the advantages of both open pond and closed photobioreactor systems
Our Greenhouse-based Algal Production System
Flocculation
Harvesting• Compatible with
wastewater treatment facility
• Bio-polymer based flocculation
Harvesting – belt filter press harvester
Compatible with wastewater treatment facility
Comparison of fossil oil and bio-oil from MAP of Chlorella sp. and fast pyrolysis of wood
Bio-oils
Properties Chlorella sp. Wooda Fossil oila
Elemental analysis (wt.%)
C 65.40 56.4 83.0-87.0
H 7.84 6.2 10.0-14.0
N 10.28 0.1 0.01-0.7
O 16.48b 37.3 0.05-1.5
HHV (MJ/kg) 30.7c 21 42
Density (kg/L) 0.98d 1.2 0.75-1.0
pH 7.0-9.5 2-3
Viscosity, at 40 oC (Pa s) 0.06 0.04-0.20 2-1000
Continuous Hydrothermal Biomass Pyrolysis System
Continuous hydrothermal system –straightened out and lengthened – attached to Gear pump with black tubing at left.
Direct Conversion of Algal Biomass into Biofuels
Algae slurry was pumping into the reactor
Algal biofuel product coming out the reactor
A: harvested algae paste B: algae paste after hydrothermal process. C: three phase formed after centrifugation of B
CA B
Our Current Status
• 35 g·m-2d-1 of TSS
• 30% total lipid content on VSS basis
• 90% COD removal
• 70% N, P removal
Http:// biorefining.cfans.umn.edu
Acknowledgments:
Related Group Members and Collaborators: B. Polta, J. Willett, A. Sealock, R. Hemmingsen, R. Larkins, J. Sheehan, K. Cavender-Bares, P. Chen, M. Min, Y. Chen, L. Wang, Yecong Li, Q. Kong, X. Wang, Y. Wan, X. Ma, L. Li, K. Hennessy, Y. Liu, X. Lin, Yun Li, Y. Cheng, S. Deng, Q. Chen, C. Wang, Y. Wang, Z. Du, X. Lu, R. Zhu, A. Olson, B. Martinez, B. Zhang, J. Zhu, B. Hu, L. Schmidt, D. Kittelson, R. Morey, D. Tiffany, H. Lei, X. Ye, P. Heyerdahl, ……
Funding Agencies:
Metropolitan CouncilEnvironmental ServicesMetropolitan CouncilEnvironmental Services
R. Roger Ruan, Ph.D.
Yangtze Scholar Distinguished Guest Professor, Nanchang University and Professor and DirectorCenter for BiorefiningDepartment of Bioproducts and Biosystems EngineeringDepartment of Food Science and NutritionUniversity of Minnesota1390 Eckles Ave., St. Paul, MN [email protected]
Q u es t io n s ?