Biomass Technologies: verview and Future Trends Small Wood 2004 Sacramento, CA May 20, 2004 John Scahill
Biomass Feedstocks Forest Wood Residues Agricultural Residues Energy Crops Thinning Residues Wood chips Urban Wood waste pallets crate discards wood yard trimmings Corn stover Rice hulls Sugarcane bagasse Animal biosolids Hybrid poplar Switchgrass Willow
Biomass Constituents H 3 C H CH 3 H 3 C H Lignin: 15-25% Complex aromatic structure Very high energy content Hemicellulose: 23-32% Polymer of 5 & 6 carbon sugar Cellulose: 38-50% Polymer of glucose, very good biochemical feedstock CH 3 CH 3 H CH H 3 H CH 3 H H H H H H H H H H H H CH 3 H 3 C H CH 3 H H H H H CH CH 3 3 H H H CH H H 3 H H H H H H H H H H H H H H H H H H H H 3 C H H H H H CH 3 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H Solid H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H Gas or Sugars Power & Liquid Fuels
Biomass Conversion Pathways Thermal Biological Physical Excess air Partial air No Air Pretreatment A/D Combustion Gasification Pyrolysis Fermentation Hydrolysis (Heat & Pressure) Heat Fuel Gases (C + H 2 ) Liquids Ethanol CH 4 Liquids H 2
Bio-Chemical Technology Process effective for converting cellulose- and hemicelluloseinto simple sugars
The Biomass Saccharification Process biomass Stage 1. mineral Pretreatment acid cellulose and lignin Stage 2. Enzymatic hydrolysis glucose and lignin hemicellulose sugars and oligomers Mineral acid gives good hemicellulose sugar yields and high cellulose digestibility Sulfuric acid usual choice because of low cost Requires downstream neutralization and conditioning Typical conditions: 100-200 o C, 50 to 95% moisture, 0-1% H 2 S 4 Some degradation of liberated hemicellulose sugars Current commercial cellulase enzyme preparations release glucose, cellobiose, and some xylose.
NREL s Enzymatic Hydrolysis Partnerships 3-year Partnerships with Genencor & Novozymes Enzyme biochemistry and specific activity Cellulase - cellulose surface interaction Reduce cost of enzyme production ($0.25/gal) Reduce risk to investors E1 from A. cellulotiticus CBH1 from T. reesei +2 +1-1 -2 Y82 cellodextrin
Schematic of an Integrated Biorefinery
Biomass Conversion Pathways Thermal Biological Physical Excess air Partial air No Air Pretreatment A/D Combustion Gasification Pyrolysis Fermentation Hydrolysis (Heat & Pressure) Heat Fuel Gases (C + H 2 ) Bio-oil Ethanol CH 4 Liquids H 2
Pyrolysis Technical Requirements Rapid heat transfer in the absence of oxygen Short residence time at temperature (msec) Thermal cleavage of macropolymer bonds (lignin, cellulose, hemicellulose) Liquids (70%), gas (15%), Char (15%)
Bio-oil Refinery Approach lignocellulosic biomass H 2 Pyrolysis Pyrolysis bio-oil SEPARATIN FRACTINATIN gas charcoal specialty carbons phenolic resins fuel additives biodiesel glycerin/lipid fraction pyrolytic lignin bio-oil aqueous fraction FLUID BED CATALYTIC STEAM REFRMING C H 2 C 2 H 2 hemicellulose fraction trap grease Shift Shift Conversion Conversion & PSA PSA extractives cellulose pulp lignin derivatives H 2 C 2 processed food TRANSESTERIFICATIN H 2 FD PRCESSING plant&animal fats raw food
Bio-il Aqueous Fraction Fluidized Bed Reforming Gas Composition 80 70 H 2 45,000 40,000 60 35,000 Vol. % 50 40 30 CH 4 30,000 25,000 20,000 15,000 Vol., ppm 20 10 C C 2 10,000 5,000 0 0 0 1000 2000 3000 4000 5000 6000 Time, min
Bio-il From More than 30 products are made today from Bio-il and process energy Pyrolysis Potential Markets / Products Liquid Liquid boiler boiler fuel fuel substitute Reform to to Hydrogen Food Food flavorings // Specialty chemicals Phenolic replacements Asphalt binders riented Strand Boards and Plywood made from Bio-il Phenolic Resins
Biomass Conversion Pathways Thermal Biological Physical Excess air Partial air No Air Pretreatment A/D Combustion Gasification Pyrolysis Fermentation Hydrolysis (Heat & Pressure) Heat (C + H 2 ) Liquids Ethanol CH 4 Liquids Synthesis gas Power and Liquid fuels H 2
Gasification Air (0.3) 2 (0.3) Steam Producer Gas (mol%) Synthesis Gas (mol%) Heat C 24 H 2 13 CH 4 3 C 2 8 N 2 52 (tars & particulate) Fuel Gases C 39 H 2 20 CH 4 17 C 2 H 2 6 C 2 18 N 2 0 (tars & particulate)
Different Gasifier Designs Biomass Biomass Cyclone Freeboard Gas, Tar, Water Gas, Tar, Water Pyrolysis C + C2 = 2C C + H2 = C + H2 Reduction C + 2 = C2 Combustion 4H + 2 = 2H2 Ash Updraft Gasifier Air Pyrolysis C + 2 = C2 4H + 2 = 2H2 Combustion C + C2 = 2C C + H2 = C + H2 Reduction Ash Downdraft Gasifier Air Ash Fluid Bed Biomass Plenum Air/Steam Fluid-Bed Gasifier Flue Gas Gasifier Primary Cyclone Secondary Cyclone Fly Ash Biomass Air/Steam Bottom Ash Circulating Fluid-Bed Gasifier Biomass N2 or Steam Char Furnace Recycle Gas Air Entrained Flow Gasifier
Entrained Flow Gasification (Steam Reforming) Flue Gas 850 C Synthesis gas Biomass Steam Burner Air Char Gas Slip stream
Staged Gasification Pyrolysis Steam Reforming 850 C Biomass + moisture Vapors + steam 700 C Pyrolysis Burner Burner Synthesis Gas Carbon Conversion Technologies 2004
General Process Description Syngas-to-Liquids xygen or Steam coal, natural gas, biomass Gasifier Gasifier Gas Gas Cleanup Cleanup and and Conditioning Conditioning Catalytic Catalytic reactor reactor Catalytic tar conversion Sulfur scrubbing Liquid Fuels Shift H2/C ratio Particulate removal Wet scrubbing
NREL TCPDU Product Gas Tar Composition 1e+5 8e+4 6e+4 Averaged mass spectrum (TMBMS) of tars from indirect wood gasification 78 78 - benzene 91,92 - toluene 94 - phenol 104 - styrene 108 - cresol 116 - indene 128 - naphthalene 142 - methylnaphthalenes 152 - acenaphthalene 166 - flourene 178 - anthracene/phenanthrene 192 - methylanthracene? 202 - pyrene/flouranthene 216 - benzo(a)flourene Source: VTT Research Center, Finland 4e+4 2e+4 91,92 128 94 116 104 108 142 152 166 178 192 202 216 Tars Tars can can be be reformed reformed to to additional additional H2 H2 + C C Nickel Nickel catalysts catalysts 850 850 --900 900 C 0 75 100 125 150 175 200
Syngas Conditioning Gasification Reactions C + C 2 2 C (Boudouard) 800-850 C C + H 2 C 2 + H 2 (Water gas shift) Control of temperature and steam content adjusts H2 / C ratio in Syngas
Gas Cleanup Requirements For Fischer-Tropsch gas-to-liquids Impurity H 2 S, NH 3, HCN < 1 ppmv Removal level HCl < 10 ppbv Soot, dust, ash Essentially completely Tars Below dew point < 1 ppmv Source: H. Boerrigter et al, ctober 2002
Syngas to Liquid Fuel ptions Biomass H2/C Catalyst Temp C PSI Ethanol Feed Prep 1.0-1.4 Cu-Zn Cu-Co thers 200-420 750-3800 Mixed Alcohols Gasification Gas Cleanup Clean Syngas H2/C 2.3 Catalyst Cu-Zn Temp C < 250 PSI 1450 Methanol DME Zeolite Cat. Gasoline H2/C 2.0 2.0 Catalyst Fe Co-K Temp C 340 240 PSI 340 370 Gasoline -Wax Diesel -Wax Hydrocracking F-T Liquids Source: NREL/TP 510-34929 Gasoline/diesel
Gas to Liquids Process Issues Recycle Compressor Tail gas Heat H2/C Ratio Catalyst Reactor Temp - Press Conversion 15-40% Pressure letdown Heat Selectivity to Desired Product Liquid Product Syngas Conditioning (cleanup) Gas Gas recycle costs Heat removal (highly exothermic)
Liquid Fuel Properties F-T Diesel (high quality) Mixed Alcohols Cetane Total aromatics Polycyclic aromatics Sulfur > 70 (conventional 45-50) < 3 (vol. %) < 0.01 (mass %) < 1 (ppm) Type Methanol Ethanol Propanol Butanol Pentanol Hexanol & higher Wt% 5-30 45-75 15 5 3 2 Source: Taylor (2002) Source: www.sasol.com
Commercial History of Gas-to-Liquids SASL (South Africa) 1955 Coal CH4 hydrocarbon fuels/chemicals Shell (Malaysia) 1993, 12,000 bbl/day Natural gas syngas gasoline BP / Davy Process Tech (Alaska) 2002 Stranded CH4 short chain hydrocarbons Compact, modular design Small barge mounted plants under development Syntroleum (Australia) under construction/shakedown
Economic Comparisons Biomass to F-T Liquids vs. Electricity Yield (1) 79.8 gal/ton Value $1.14+.21=$1.35/gal (3)(4) $/ton biomass $108 (2) 455 kwh/ton (combustion-steam turbine) Purchase agreement $0.02-.04 / kwh Levelized CE $0.07 / kwh (2) $9 - $18 $32 Basis: 50 50 wt% wt% conversion conversion biomass biomass to to syngas syngas 1. 1. 10,000 10,000 ft3 ft3 syngas/bbl syngas/bbl syncrude syncrude (Hydrocarbon (Hydrocarbon Processing Processing Feb Feb 2003) 2003) 2. 2. 455 455 kwh/g kwh/g ton ton biomass, biomass, $.07/kWh $.07/kWh CE CE (McNeil (McNeil Technologies Technologies Nov Nov 2003) 2003) 3. 3. EIA EIA current current diesel diesel production production cost cost (May (May 9, 9, 2004) 2004) 4. 4. EIA EIA estimate estimate of of FT FT diesel diesel premium premium value value - - $9/bbl $9/bbl
Biomass Conversion Pathways Thermal Biological Physical Excess air Partial air No Air Pretreatment A/D Combustion Gasification Pyrolysis Fermentation Hydrolysis (Heat & Pressure) Heat Fuel Gases (C + H 2 ) Liquids Ethanol CH 4 Liquids H 2
Biomass Combustion for Heat Increasing interest Industrial parks Multiple buildings (district heating) High natural gas costs Source: BioEnergy Corp. Nederland, C
Biomass Power Applications Combustion / steam turbine mature but low efficiency Small modular systems - emerging technology Gasification combined cycle under development
Biomass is the only renewable resource that causes problems when it is NT used!