Integrated Biorefining –
Lignocelluloses to bio-fuels,
fiber, energy and other products
Shri Ramaswamy
Dept. of Bioproducts and Biosystems Engineering College of Food, Agricultural and Natural Resources
Sciences
University of Minnesota
Collaborators and co-PI:
Hua-Jiang Huang, Ulrike Tschirner, Waleed Al-Dajani Bioproducts and Biosystems Engineering
University of Minnesota Richard Cairncross,
Chemical & Biological Engineering, Drexel University Ken Valentas, Marc von Keitz
BTI, University of Minnesota
Vernon Eidman, Steven Polasky,
Applied Economics, University of Minnesota
Lignocellulose Conversion Strategies Biomass – Nature’s most ready energy source
“Sugars”
- locked in a complex polymer composite - resist chemical and biological degradation
• Challenge/Opportunity
Breakdown what nature took Mil. years to perfect
Better understand plant cell wall physical and chemical structure
Engineer crops – “energy crops”
Efficient breakdown of lignocelluloses
Lignocellulose Conversion Strategies
• Thermochemical Conversion
• Biochemical Conversion
Chemical Fractionation of Lignocellulose
acidic conditions basic conditions
NUMBER OF STAGES Temperature
YIELDS OF MAJOR COMPONENTS Byproducts
TREATMENT OF WASTE STREAMS Chemical recovery
OVERALL COSTS
Enzymatic Fractionation of Lignocellulose
Pretreatment—chemical reagents or enzymes?
NUMBER OF STAGES IN OVERALL PROCESS Temperature
DEPLOYMENT OF CELLULASES, HEMICELLULASES AND LIGNINASES Effect of inhibitors
Optimization of enzyme kinetics in multicomponent systems YIELDS OF MAJOR COMPONENTS
Byproducts
ENZYME RECOVERY Overall Costs
Wood or other plant material
Gasification Syn-Gas
Hydrogen, Methanol, Methane, Hydrocarbons, Formaldehyde, exc.
Liquefaction
Bio-diesel
Saccharification
Glucose Xylose Lignin
ethanol Plastics
Defibering
Composites Pulp fiber
Paper and other products
Combustion
Energy
Lignin/org.
O2
¬Pulp
¬Paper
CO2
Steam, Power &
Chemicals
¬BL Recovery Boiler
¬Power Boiler
Black Liquor
& Residuals
Current Pulp and Paper Operation
Conversion to Energy
Manufacturing Purchased Power – 6 GW
$2.0 billion 90 x 106 MT CO2
Slide Courtesy of Ben Thorp (formerly with GP)
O2
¬Pulp 55 m. tons
$5.5 billion Steam,
Power &
Chemicals
¬BL Gasifier
¬Wood Residual Gasifier
¬Combined Cycle System
¬Process to manufacture Liquid Fuels and Chemicals
Black Liquor
& Residuals
The Forest Biorefinery
Manufacturing SyngasSyngas
66 x 106 MT CO2
¬Extract Hemicelluloses
¬new products
chemicals polymers 1.9 b. gal ethanol
600 m. gal acetic acid
$3.3 billion
Power Export
$3.8 billion Or
Liquid Fuels/Chemicals
$5.5. billion
Net Revenue Assumptions:
Acetic Acid - $1.73/gallon Purchased Electricity - $43.16/MWH Ethanol - $1.15/gallon Exported Electricity - $40.44/MWH Pulp - $100/ton net profit Renewable Fisher Tropsch Fuel - $57/bbl
Slide Courtesy of Ben Thorp (formerly with GP)
The overall project
Integrated Biorefinery
– Process Model
Integrated Biorefinery - Overall Approach
Lignocellulose to Liquid Fuel and Energy – without fiber separation
ASPEN PLUS (NREL type)
Integrated Biorefinery - Overall Approach
Lignocellulose to Liquid Fuel, Energy and Fiber
Extending current pulp and paper operation – including gasification and
hemicellulose and cellulose (short
fiber) to liquid fuels, and pulp (long fiber) - SYNGAS to chemicals and products
WINGEMS
Integrated Biorefinery - Overall Approach
Integrate the two models – to obtain comprehensive, flexible
Integrated Biorefinery Process Model Adapt and Improve as new
technologies emerge
Lignocellulose to Bio-fuel – Process Model
Objectives – Phase I
Lignocellulose to Liquid Fuel (ethanol)
Effect of biomass species and chemical
composition on overall process efficiency and
economic performance
Process Design Basis – Biomass Species – Aspen, Hybrid Poplar, Switchgrass, Corn
Chemical composition
Component Aspena Hybrid poplarb Switchgrassb Corn Stoverc Cellulose/Glucan 53.02 43.67 33.75 37.4 Xylan 19.09 15.63 22.13 21.1 Arabinan 4.24 0.71 2.81 2.9 Mannan 2.12 2.27 0.19 1.6 Galactan 1.59 0.94 0.89 2.0 Lignin 19.09 27.23 16.82 18.0 Ash 0.85 1.35 5.96 5.2 Extractives 0 3.39 15.55 4.7
Acetate 0 0 0 2.9
Protein 0 0 0 3.1
Soluble Solids 0 4.81 1.89 1.1
Process Design Basis
Major Operating Conditions
Acid Concentration 1.1%
Solids in the Reactor 30%
Temperature 463.15 K (190°C)
Pressure 1226.0 kPa (12.1 atm)
Pretreatment
Residence Time 120 sec
Cellulase Loading 12 FPU/g cellulose Initial Saccharification Solids Level 20% total solids
Temperature 338.15 K (65°C)
Total Residence Time 36 h
Size of Vessels 3,596 m3 each
Number of Vessels 5
Saccharification
Number of Continuous Trains 1
Process Design Basis
Major Operating Conditions (contd.)
Organism Zymomonas mobilis strain
Initial Fermentation Solids Level 20% total solids
Inoculum Level 10%
Corn Steep Liquor (CSL) Level 0.25%
Diammonium Phosphate (DAP) Level
0.33 kg/m3 fermentation broth
Temperature 314.15 K (41°C)
Total Residence Time 36 h
Size of Vessels 3,596 m3 each
Number of Vessels 5
Co-
Fermentation
Number of Continuous Trains 1
Effect of Biomass Species on Ethanol Production (2000 TPD Biomass Feedstock Rate)
Effect of Biomass Species on Excess Electricity Generated (2000 TPD Biomass Feedstock Rate)
Effect of Plant Size on Radius of Collection for various Biomass Species (assuming U.S. upper Midwest and literature data)
Effect of Plant Size on Delivered Feed Stock Cost for various Biomass Species (assuming U.S. upper Midwest and literature data)
Effect of Plant Size on Ethanol Production Cost for various Biomass Species
Phase I Summary
On the basis of lowest cost, Aspen is preferred biomass species for ethanol among the four
species considered
Availability and costs – dependent on geographic location
Switch grass and corn stover – potential alternatives – dependent on availability
Relationship between plant size and ethanol cost – non-linear – dependent biomass species
Suitable plant size 2000 – 4000 Mg/day feedstock
Further Work
Continue to update lignocellulose to liquid fuel model based on process research results
Develop a lignocellulose to liquid fuel, including fiber, energy and other products model using WINGEMS
Integrate the two models – comprehensive tool
Integrated Biorefinery Process Model
Acknowledgement
