Biofuels Research at the University of Washington 15 July 2008 Rick Gustafson Paper Science & Engineering College of Forest Resource University of Washington
UW biofuels research agenda Vision: Cost effective cellulosic transportation fuels Use mixed biomass sources With good process yields Profitable at moderate economies of scale Co-produce fuels and high value products Commodity Chemicals Polymers Pulp Fibers
UW research initiatives three examples High-throughput screening process for evaluation of lignocellulosic biomass Use of membranes to recover hemicellulose from aqueous streams Ethanol from Municipal solid waste (MSW)
High-throughput screening process for evaluation of lignocellulosic biomass Fractionation Bioethanol Xylitol Bio-adhesives Biogas Biomethanol Hydrogen Biobutanol Biodiesel Biopolymers Biochemicals Bio-oil 4
Lignocellulosic ethanol platform Raw biomass Pretreatment Pretreated solids Pretreated liquid Enzymatic hydrolysis Lignin Glucose Fermentation Lignin Cellulose Hemicellulose Extractives, ash, etc Glucose Other sugars Ethanol 5
Proposed research High throughput screening of multiple biomass types Experimental method development Enzymatic hydrolysis Fermentation Analytical method development Lignin Cellulose Hemicellulose Extractives, ash, etc Glucose Other sugars Ethanol 6
Research objectives Fractionation versus 7
Method development Conventional Micro Experimental Flask scale (125ml) 96 wells (0.3 ml/well) Analytical Raman Near IR HPLC, GC, wet chemistry 8
High throughput hydrolysis Pretreated substrate Shaker Handsheet Berlin et al., 2006 Analysis 9
Analytical requirements Components to be measured: Starting biomass Cellulose, hemicellulose, lignin Pretreated substrates Solids: Cellulose, hemicellulose, lignin Liquid: Glucose, hemicellulosic sugars, inhibitors 10
Analytical requirements Hydrolysis Conversion of cellulose to glucose over time Glucose Time Fermentation Conversion of glucose to ethanol over time Consumption of inhibitors Production of by-products Glucose Time By-products Ethanol 11
Raman spectroscopy Analytical techniques Shown to be effective to measure complex mixtures of carbohydrates and other compounds Near-IR spectroscopy Can be effectively used to measure lignin Single fiber analyzer Measure particle characteristics and lignin content 12
Existing bioethanol plants Over 130 in US (all corn-based) Potential applications Require means to monitor glucose and ethanol levels in real time during hydrolysis and fermentation Enzyme developers High consistency solids hydrolysis Improved conversion efficiency Fermentative organism development Bioengineering for pentose fermentation Increased temperature tolerance 13
Novel Membranes for Separation and Concentration in Lignocellosic Biorefinery 66 x 10 6 MT CO 2 O 2 Powerhouse of the Future Power Export 20 GW or New Products Liquid Fuels Chemicals Polymers Black Liquor & Residuals Syngas Extract Hemicelluloses new products chemicals polymers Cellulosic Biomass BL Gasifier Wood Residual Gasifier Combined Cycle System Process to manufacture Liquid Fuels and Chemicals Steam, Power & Chemicals Manufacturing Pulp Paper
Hemicellulose Extraction U.S. Kraft pulp mills process roughly 25 million tons of hemicellulose each year Hemicellulose Ethanol 25 million tons 2 billion gallons Current US ethanol production is about 7 billion gallons
Hemicellulose Extraction Extraction Hemicellulose from Biomass Hot water extraction Hardwoods & wheat straw Dilute acid extraction Softwoods Alkaline peroxide treatment Wheat straw 97% water Extractives Lignin Hemicelluloses Water Composition of Extraction Liquor
Biopolymer Concentration Removal of Water 2% Hemicellulose 20% Hemicellulose Membrane Separation Non-volatile Components Lower energy 2/3 1/2 that of evaporation Remove inhibitors as well as water Potential for fouling High capital cost
Research Objectives Assess and optimize membrane separation on biorefinery streams Process synthetic and commercial process streams Assess variables in membrane experiments Membrane pore size Process parameters Develop methods to characterize and rapidly assess membrane performance Real time compositional analysis of biorefinery process streams. Use flexible sampling and sensor platform developed by CPAC
Approach Feed Volume:4 ml Membrane Pore Size Screening Feed Volume:500 ml Sugar Recovery Feed Volume:3 liter Process Optimization
NaOH (% on O.D.) 10 Peroxide (% on O.D.) 5 Temperature ( o C) 57 Time (hr) 2 Materials Synthetic process stream Composition: Beechwood xylose (>90% xylose residues) Concentration: 1.0% Molecular Weight of Xylan: ~8,000 Dalton Commercial stream Species: Wheat Straw Extraction conditions:
Schematic for Dead End Filtration Syringe pump Syringe Holder with disc membrane Filtrate
Xylan Dead End Filtration Results 100 80 Xylan retention (%) 60 40 20 0 1 3 5 10 30 50 100 300 Membrane MWCO (KDa)
Black Liquor Dead End Filtration Results Solid recovery (%) 100 80 60 40 20 7 6 5 4 3 2 1 Filtration Time (hrs) 0 1 3 5 10 30 50 100 300 Membrane MWCO (kda) 0
Schematic for Minimate TFF System Feed Flow Feed Filtrate Minimate TFF Capsule Pressure Gauge Vent Retentate Peristaltic Pump Screw Clamp Retentate Flow Filtrate Flow Ambient Temperature Pressure: 0~2 bar Filtration stopped when 50% of feed is in filtrate 5K and 10K membranes Pictures from Pall.com
Total Sugar Conc. in Filtrate & Retentate Percentage of Feed (%) 120 100 80 60 40 20 1.0 bar Filtrate 1.0 bar Retentate 0.5 bar Filtrate 0.5 bar Retentate 0 Arabinose Galactose Glucose Xylose Mannose
Schematic for Pilot Unit System 1. Feed tank 2. Recirculation pump 3. Membralox T1-70 module 4. BF3 backpulse device Picture from Pall.com
Total Sugar Conc. in Filtrate & Retentate Sugar Fraction Ratio (%) 1.20 1.00 0.80 0.60 0.40 2.0 bar Filtrate 2.0 bar Retentate 1.5 bar Filtrate 1.5 bar Retentate 1.0 bar Filtrate 1.0 bar Retentate 0.20 0.00 Arabinose Galactose Glucose Xylose Mannose
Optimize membrane operation Pilot Unit System Proposed Research Investigate separation performance of ceramic membranes 10k and 5k membranes Process variables Temperature Pressure Backflushing time and frequency Goal is to optimize flux of filtrate
Municipal Solid Waste Municipal Solid Waste LOTS OF CELLULOSE Mixed Waste Paper Yard Waste Synthetic Garbage
Bioconversion of mixed paper to ethanol (2) Lignin Pretreatments Hydrolysis Fermentation Sugars Ethanol Cellulose Hemicellulose
Pretreatments for mixed paper Mixed paper Hydropulping (30min) Deinking (20min) Screening Chemical composition (cellulose, hemicellulose, lignin, and ash) + enzymatic hydrolysis
Compositional analysis of mixed paper Ara Gal Cell Xyl Man Ash Lignin (%) (%) (%) (%) (%) (%) (%) Hydropulping 0.9 0.8 62.7 8.9 4.3 10.2 10.2 Deinking 0.9 0.8 71.5 9.6 4.6 5.8 16.7 Deinking+ Screening 0.9 0.8 78.3 10.3 5.3 2.2 12.2 Foam rejects 1.0 0.9 55.1 7.6 3.6 21.3 20.5
Enzymatic hydrolysis Pretreated substrate Flasks Sugar analysis HPLC
Enzymatic hydrolysis-conversions Glucose g/l Cellulose to glucose conversion (%) Hydropulping 3.4 27.0 Deinking 4.4 30.8 Deinking+ Screening 2.9 18.5 Foam rejects 1.3 11.8
LCA analysis: Base Scenario (current waste management regime)
LCA analysis: Alternative Scenario
Other UW biofuels projects Novel yeasts for fermentation and xylitol production Production of bioethanol from various raw materials sources using steam explosion pretreatment Switchgrass Sugar cane Giant reed Hybrid poplar Hybrid process to produce ethanol and glycols from cellulosic biomass Genetic modification of biomass for biofuels production Co-production of pulp and bioethanol