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NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy operated by the Alliance for Sustainable Energy, LLC
1313thth Annual Green Annual Green Chemistry & EngineeringChemistry & Engineering
ConferenceConference
Luc Moens, Ph.DLuc Moens, Ph.D
June 25, 2009June 25, 2009
Upgrading of BioUpgrading of Bio--oil oil for Fuel Productionfor Fuel Production
Topics
• What is bio-oil?
• Lignocellulosic biomass – composition
• Bio-oil • properties• chemical composition
• Upgrading
• Future R&D: catalytic pyrolysis
National Renewable Energy Laboratory Innovation for Our Energy Future
From Biomass to Bio-oil: Pyrolysis
National Renewable Energy Laboratory Innovation for Our Energy Future
300
900
600
T (°C)
GasificationGasification
PyrolysisPyrolysis
CO + H2
syngas
BioBio--oiloil
Liquid Fuels
BiomassBiomass
???
Fischer-Tropschprocess
From Biomass to Bio-oil: Pyrolysis
National Renewable Energy Laboratory Innovation for Our Energy Future
300
900
600
T (°C)
PyrolysisPyrolysis
BioBio--oiloil
BiomassBiomass
Fast pyrolysisFast pyrolysis
no oxygen 450°- 550°Crapid heating (>1000°C/s)short residence times (1-2 s)
From Biomass to Bio-oil: Pyrolysis
National Renewable Energy Laboratory Innovation for Our Energy Future
300
900
600
T (°C)
PyrolysisPyrolysis
BioBio--oiloil
BiomassBiomass
Fast pyrolysisFast pyrolysis
~75 wt% liquid product yield(25 wt% = char + gas)
can be transported / storedconversion into
fuels & chemicals
Biomass feedstocks
National Renewable Energy Laboratory Innovation for Our Energy Future
Ag residues
Forest residues
Willow
Switch grass
Hybrid poplar
Lignocellulosic Biomass
National Renewable Energy Laboratory Innovation for Our Energy Future
O
O
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O H
O H
O H
H O
H O
O HO
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H O
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O HO
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O H
O H
H O
H O
O HO
LigninLignin 15% - 25%• complex aromatic structure• resists biochemical conversion
HemicelluloseHemicellulose 23% - 32%• carbohydrate polymer• C5 and C6 sugars(xylose-based)
Cellulose Cellulose 38% - 50%• glucose polymer (C6 )
Fast Pyrolysis Bio-oil
National Renewable Energy Laboratory Innovation for Our Energy Future
5% methanol addition
Homogenization
• Density ~ 1.2 kg/L
• Combustible (HHV~18 MJ/kg)
• Contains 20-30% H2O
Partly miscible with water
Non-miscible with hydrocarbons
• Highly acidic: pH ~ 2.5 (corrosive!)
• Strong phenolic odor
Fast Pyrolysis Bio-oil
National Renewable Energy Laboratory Innovation for Our Energy Future
5% methanol addition
HomogenizationHigh degree of oxygenation
C 40-48%, H 7-8%, O 44-52% (wet basis)
C 53-57%, H 7-7.5%, O 36-40% (dry basis)
(cfr. heavy fuel oil - C 85%; H 11%; O 1%)
Fast Pyrolysis Bio-oil
National Renewable Energy Laboratory Innovation for Our Energy Future
5% methanol addition
Homogenization
Bio-oil changes properties during storage
• increase in viscosityrate = 2.317∗1013 exp(-9659/T) cP/day
• decreased volatility• phase separation• formation of gums and deposits
Instability is caused by thermochemical processes that lead to cross-linking of C=O compounds
(Diebold, J.P.; Czernik, S., Energy Fuels 1997, 11, 108)
Bio-oil: chemical composition
National Renewable Energy Laboratory Innovation for Our Energy Future
Fresh bio-oil is a homogeneous emulsion of > 300 organic compounds
Wt % of bio-oilC1 (formic acid, methanol) 5 - 10C1-C4 aldehydes, glyoxal,hydroxyketones, carboxylic acids 15 - 35
C5-C6 furfuraldehydes, furanones,pyranones 10 - 20
Anhydrosugars (levoglucosan) 6 - 10Carbohydrate oligomers 5 - 10Phenolics 6 - 15Pyrolytic lignin (oligomeric phenolics) 15 - 30
“unidentified” ~ 20
Radlein, D., The Production of Chemicals from Fast Pyrolysis Bio-oils, in Fast Pyrolysis of Biomass; A Handbook
ligninderived
cellulosederived
Bio-oil properties
National Renewable Energy Laboratory Innovation for Our Energy Future
Bio-oil + water
Phase separation
5% methanol addition
Homogenization
Oasmaa, A.; Czernik, S., Energy & Fuels, 1999, 13, 914-921.
• Bio-oil contains ~ 20% H2O• [H2O] ≥ 30% phase separation
From Bio-oil to Liquid Transportation Fuels
National Renewable Energy Laboratory Innovation for Our Energy Future
Refinery
PetroleumPetroleum
BioBio--oiloil
Diesel
Liquid FuelsLiquid Fuels
• High acidity (corrosive)• High oxygen content (~40%)
(too high for hydrotreatment/hydrocracking)
Technical barriersTechnical barriers
Jet fuelGasoline
Diesel
From Bio-oil to Liquid Transportation Fuels
National Renewable Energy Laboratory Innovation for Our Energy Future
Refinery
PetroleumPetroleum
BioBio--oiloil
Diesel
Liquid FuelsLiquid Fuels
Jet fuelGasoline
Diesel
“UpgradingUpgrading” through chemical modification
• neutralization of acids• stabilization (no cross-linking by C=O groups)
Bio-oil Neutralization & Stabilization
National Renewable Energy Laboratory Innovation for Our Energy Future
R OH
OR1OH
R OR1
OH2O
acid
R H
O
aldehyde
2 R1OHR OR1
OR1
H2O
alcohol
alcohol
ester
acetal
H+
H+
• Reactions are equilibrium-limited 20 wt% residual acid • Excess water from crude bio-oil (20-30%) and condensation reaction• Acid catalyst required • Stoichiometric amount of ROH needed (high cost!)
DisadvantagesDisadvantages
Moens, L.; Black, S. K.; Myers M. D.; Czernik, S. Energy Fuels 2009, 23, 2695
Bio-oil Hydroprocessing (H2)
National Renewable Energy Laboratory Innovation for Our Energy Future
• Review: Elliott D. C. Energy Fuels 2007, 21, 1792
• Commercial catalysts: NiMo, CoMo, precious metals
• High T / P conditions achieve hydrodeoxygenation
• Compatible with petroleum refinery infrastructure
• Range of hydrocarbon products (gasoline-type):
aromaticscycloalkanes
• Only lignin-derived phenolics are relevant (only ~25% of biomass)
• use of added H2 cost is an issue
Lignocellulosic Biomass
National Renewable Energy Laboratory Innovation for Our Energy Future
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O C H 3
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H 3C O
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O C H 3
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H O
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O H
O H
H O
H O
O HO
LigninLignin 15% - 25%• complex aromatic structure• resists biochemical conversion
HemicelluloseHemicellulose 23% - 32%• carbohydrate polymer• C5 and C6 sugars(xylose-based)
Cellulose Cellulose 38% - 50%• glucose polymer (C6 )
Synthesis of larger Carbon Units
National Renewable Energy Laboratory Innovation for Our Energy Future
HO CHO CH3CHO OHC-CHO OHO
OCHO
OCHO
OH
… ongoing R&D
Can these small oxygenates be “polymerized” to form larger molecules (C9 – C20 units)?
Catalytic Pyrolysis
National Renewable Energy Laboratory Innovation for Our Energy Future
Diesel
Liquid FuelsLiquid Fuels
Jet fuel DieselGasoline
Catalytic Pyrolysis
BiomassBiomass
catalyst system “improved”bio-oilvapors modified
vapors
• eliminate coking• mechanisms of thermochemistry• “multifunctional” catalysts
R&D needsR&D needs
Acknowledgment
Co-workers:
Dr. Stefan Czernik (mentorship)Stuart K. BlackMichele Myers
US Dept. of Energy – Office of Biomass Program
National Renewable Energy Laboratory Innovation for Our Energy Future
Luc.moens@nrel.gov
National Renewable Energy Laboratory Innovation for Our Energy Future