The Potentially Promising Technologies for Conversion Woody Biomass to Sugars for Biofuel Production: Technology and Energy Consumption Evaluation J.Y. Zhu US Forest Service, Forest Products Laboratory, Madison, WI 2009 TAPPI International Bioenergy and Bioproducts Conference October 13, 2009
Barriers to Biobased Economy Can we do it technologically? Can we do it economically? Can we do it sustainablly? Can we do it ENERGY efficiently?
Biorefinery Economic Analysis $$ Capital What about net energy output? Biorefinery $$$ Value $$ Processing
Chemicals Enzymes Yeast Engineering Analysis Energy How much is net energy output? Biofuel
Material and Energy Analysis Energy Mixing energy Energy Heat A A Glucan: Mannan: Xylan: Lignin: Ethanol: Lignin: Energy C Energy Energy 1000 Glucan: Mannan: Xylan: Lignin: B B+C Glucan: Mannan: Xylan: Lignin: Ethanol: Lignin: Energy
Process Performance Evaluation Total Sugar Yield Pretreatment Process Efficiency ηpretreatment = Total sugar yield / Energy Input
Process Performance Evaluation Total Ethanol Yield Ethanol Production Energy Efficiency ηenergy = Net energy output / Energy Input
Feedstock Comparison 150-650 Wh/kg 50 Wh/kg 1.3 cents/liter ~50 Wh/kg Cornstover
Two Key Barriers to Woody Biomass Conversion Size reduction energy consumption Recalcitrance Low cellulose conversion, especially softwoods
Size reduction Energy Consumption in Pretreatment Nonwoody: 50 Wh/kg = 0.18 MJ/kg Woody: 200-600 Wh/kg = 0.72 2.18 MJ/kg Thermal energy Temperature L/S Ratio 1. 180 o C aqueous @ L/S = 3 ~ 2.460 MJ/kg Biomass ~ 1.3 2. 180 o C aqueous @ L/S = 5 ~ 4.182 MJ/kg Biomass ~ 2.1 3. 215 o C steam @ L/S = 1 ~ 3.508 MJ/kg Biomass ~ 1.8
Energy Consumption in Pretreatment Total energy Non-woody 1. 180 o C aqueous @ L/S = 3 ~1.48 MJ/kg 2. 180 o C aqueous @ L/S = 5 ~2.28 MJ/kg 3. 215 o C steam @ L/S = 1 ~1.80 MJ/kg Woody 1. 180 o C aqueous @ L/S = 3 ~2.02 3.48 MJ/kg 2. 180 o C aqueous @ L/S = 5 ~2.82 4.28 MJ/kg 3. 215 o C steam @ L/S = 1 ~1.80 MJ/kg 20% 32% 25% 28-48% 40-60% 25% Biomass ethanol Energy ~80 gallon/ton of biomass (OD); Ethanol HHV = 90 MJ/gallon Biomass ethanol energy = 7.2 MJ/kg
CAFI-II Study Biomass Refining Consortium for Applied Fundamentals and Innovations (CAFI) CAFI II: Poplar wood pass ¼ mesh Process studied: Dilute acid + steam explosion (NREL) Acid Catalyzed steam explosion (UBC) Lime (TX A&M) Ammonia recycle percolation-arp (Auburn) Ammonia fiber expansion-afex (Michigan State) Controlled ph (Purdue)
CAFI-II (Poplar) Findings Pretreatment Glucose Xylose Total Wt % Theoretical Theoretical 438 149 587 100 Dilute acid 380 107 486 83 Steam Explosion 439 95 533 91 Controlled ph 237 62 299 51 AFEX 233 77 310 53 ARP 214 46 260 44 Lime 397 97 494 84
CAFI-II (Poplar) No energy data for wood size-reduction to pass ¼ mesh No liquor/solid ratio in pretreatment No solids loading in SSF No fermentation of hemicellulose sugar stream Cannot calculate ethanol yield/ton wood!! Cannot determine process energy efficiency!! 4 of the 6 process are not suited for woody biomass!!
Cellulosic Ethanol Technology Status Few carried out the complete process study to produce data for economic analysis Few reports ethanol productivity?? gallons / ton biomass
Pretreatment Technologies Steam Explosion Oganosolv Dilute Acid (including hot-water) Alkaline (Ammonia, AFEX, lime, NaOH) SPORL
Steam Explosion Pretreatment SO 2 Concentration = 0.5 5 % T = 180-240 o C Steam explosion A lot of steam lost Pre-Steam Scale-up facility not commercially proven Extractor Hemicellulose Low conversion for softwood Substrate Hydrolysis Fermentation
Organosolv Pretreatment Ethanol = 50% (v/v) ph = 2-3.4 T = 180-220 o C Lignin Pre-Steam Extractor Recovery Hemicellulose Cellulose Hydrolysis Fermentation
SPORL Technology Platform
SPORL Pretreatment Biomass T ( o C) Reaction time (min) L/S Acid charge (wt% DM) Bisulfite charge (wt% DM) Agricultural residue 170 20 3-4 0.6 2 Hardwoods 170 20 2-3 1.1 3 Softwoods 180 25 2-3 1.6 8 Typical size reduction energy: 50-100 KWh/ton wood Typical enzymatic glucose yield: 85-90% theoretical Overall sugar recovery: >85% theoretical Typical energy efficiency: 0.4 kg/mj
SPORL Substrate Digestibility Enzymati cellulose conversion (%) 100 90 80 70 60 50 40 30 20 10 Acid 0 1.4 2.21 Bisulfite 8 4 0 0 10 20 30 40 50 60 70 80 Enzymatic saccharification time (h)
1024 Disk-Milling Energy and Substrate Digestibility Disk-milling energy (Wh/kg od untreated wood) 512 256 128 64 32 16 Pretreatment ph(t=0) Untreated Hot water 5.0 Dilute acid 1.1 SPORL 4.2 SPORL 1.9 8 0 10 20 30 40 50 Milling solid consistency (%) EHGY ( wt% of wood) 48 44 40 36 32 28 24 20 16 12 8 4 Theoretical glucose 43 wt % wood 85-90% theoretical Pretreatment ph(t=0) Untreated Hot water 5.0 Dilute acid 1.1 SPORL 4.2 SPORL 1.9 0 10 20 30 40 50 Milling solids consistency (%)
512 Disk-Milling Energy and Substrate Digestibility Disk-milling energy (Wh/kg od untreated wood) 256 128 64 32 16 8 Pretreatment ph(t=0) Hot water 5.0 Dilute acid 1.1 SPORL 4.2 SPORL 1.9 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Disk-plate gap (mm) EHGY (wt% of wood) 44 40 36 32 28 24 20 16 12 Theoretical glucose 43 wt % wood 85-90% theoretical Pretreatment ph(t=0) SPORL 1.9 y = 42.9-2.15x, r 2 = 0.76 SPORL 4.2 y = 43.8-3.63x, r 2 = 0.97 Dilute acid 1.1 y = 16.6-0.36x, r 2 = 0.36 Hot water 5.0 y = 19.0-3.38x, r 2 = 0.94 8 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Disk-plate gap (mm)
Pretreatment Evaluation Steam Explosion, Soderstrom et al. 2004, Biotech Prog. 20:744 Organosolv, Pan et al., 2008, Biotech Bioeng. 101:39 SPORL, Zhu et al., 2009, Biores Techno, 100:2411
Pretreatment Energy Consumption L/W T ( o C) Net thermal energy 1 Wood chipping energy Chip milling energy Total size reduction energy 1 Total energy 1 Steam explosion 1 215 1.8 / 25 0.18 0 0/0 1.98/28 Organosolv 4 180 1.6 / 22 0.18 0 0/0 1.78/25 SPORL 3 180 1.2 / 17 0.18 0.18 0.54 0.36 / 5 0.72 / 10 1.56/22 1.94/27
Pretreatment Sugar Yield Evaluation Measure Unit Steam Exp 1 Organosolv 2 SPORL 3 Species Glucan Mannan Xylan Sum Spruce 53.2% 11.9% 4.3% 69.4% Lodgepole pine 43.2% 11.6% 7.1% 61.9% Spruce 43.2% 11.5% 5.7% 60.4% Wood chipping energy MJ(kWh)/ton wood 180(50) 180(50) 180(50) Chemical pretreatment conditions: Temperature L/W 215 o C 170 o C 180 o C 1.0 4.0 / 3.0 3.0 Chemical pretreatment energy MJ/ton wood chips 1797 1433 / 1074 1143 Wood chip size-reduction energy MJ(kWh)/ton wood 0 0 540(150) / 180(50) Total energy consumption MJ/ton wood 1977 1613 / 1254 1863 / 1503 Pretreatment soluble sugar yield kg/ton wood 211 134 228 Mannose Glucose Xylose 78 100 33 62 35 37 112 68 48 Cellulase loading FPU/cellulose 25.9 20 24.4 Enzymatic hydrolysis glucose yield kg/ton wood 346 347 372 Total monomeric sugar yield @ 65% carbohydrate equivalent kg/ton wood 557 522 481 505 600 646 Sugar recovery % theoretical 72 70 89 Pretreatment energy efficiency, η @ 65% carbohydrate equivalent kg/mj 0.26 0.31 / 0.40 0.35 / 0.43
Preliminary Ethanol Yield Evaluation K Lignin Arabinan Galactan Rhamnan Glucan Xylan Mannan G+M 1 Total 270.1 15.6 22.3 7 425.5 69.3 109.9 535.4 941.2 Sample Label EHGY @72 h 1 SSF Ethanol 2 SSF fermentation efficiency 3 Hydrolysate glucose + mannose 1 Hydrolysate Ethanol 2 Hydrolysate fermentation efficiency 3 Total glucose+ mannose 4 1-A2B0-1 158.0 0 0.00 50 0.0 0.0 208 Total Ethanol yield 5 1-A2B4-1 286.2 136.7 73.7 125.4 42.1 51.8 420 / 69.7 178.8 / 46.4 1-A2B8-1 385.9 209.4 83.8 109.7 57 80.2 517.6 /85.9 266.4 / 69.1 2-A2B8-2 396.9 229.8 89.4 99.5 1.6 2.5 496.8/ 82.5 231.3 / 60.0 3-A2B8-3 397.5 207.9 80.7 91.8 37 62.2 496.1/ 82.4 244.9 / 63.6 2-A1B8-1 398.5 227.9 88.3 88 32.1 56.3 487.9 / 81.0 259.9 / 67.4 3-A1B8-2 390.5 193.2 76.4 79.6 30.2 58.6 470.3 / 78.1 223.3 / 58.0 2-A0B8-1 366.3 165.6 69.6 23 1.4 9.4 392.3 / 65.1 166.5 / 43.2 3-A0B8-2 363.6 167.2 71.0 21.2 0.5 3.6 382.7 / 63.5 167.7 / 43.5
Material and Energy Analysis 0.41 (113 Wh/kg) NA 0.18 (50 wh/kg) 1.33 603 A Glucan: 385 Mannan: 4 Xylan: 8 Lignin: 195 Ethanol: 209 Lignin: 195 NA C NA NA Ethanol 1000 Glucan: 426 Mannan: 110 Xylan: 69 Lignin: 271 B 397 Glucan: 32 Mannan: 86 Xylan: 27 Lignin: 76 Ethanol: 57 Lignin: 76 266 Liters 4.31 GJ/ton wood
Conclusions Both total sugar/ethanol yield and process energy efficiency should be used in technology evaluation Limited process and yield data are available for good economics analysis We report ethanol production from lodgepole pine, softwood at 266 liters/ton wood Net energy out put of 4.31 GJ/ton wood before distillation SPORL pretreatment appears the best process for woody biomass in terms of energy efficient, sugar yield, scalability, lignin co-products potential
Contributors and Collaborators Visiting Scholars and Students Dr. Gaosheng Wang Tianjin Univ. of Sci. Technology 2007-2008 Mr. Wenyuan Zhu South China Univ. Technology 2008-present Mr. Hao Liu South China Univ. Technology 2008-present Dr. Shen Tian Capital Normal University 2009-present Mr. Xiaolin Luo South China Univ. Technology 2009-present Technical Staff Rollie Gleisner Tim Scott Fred Matt Diane Dietrich Collaborators Dr. Xuejun Pan, University of Wisconsin, Madison, WI Dr. Andy Youngblood, US Forest Service, Pacific Northwest Station Dr. Jose Negron, US Forest Service, Rocky Mountain Station Dr. Don Rockwood, University of Florida, Gainsville, FL Dr. Bruce Dien, USDA ARS NCAUR, Peoria, IL Dr. Lewis Liu, USDA ARS NCAUR, Peoria, IL Dr. Masood Ahtar, Biopulping International Dr. Thomas Jeffries, US Forest Service, Forest Products Laboratory