Thermochemical Conversion of Biomass to Fuel.cenusa brown 5-25-12
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Transcript of Thermochemical Conversion of Biomass to Fuel.cenusa brown 5-25-12
Center for Sustainable Environmental Technologies
The Thermochemical Option
Robert C. BrownRobert C. Brown
Center for Sustainable Environmental Technologies
Iowa State UniversityIowa State University
CenUSA WebinarMay 25, 2012
Center for Sustainable Environmental Technologies
What is the Perfect Energy Carrier for Transportation Fuel?What is the Perfect Energy Carrier for Transportation Fuel?
d b d• Liquid at ambient conditions• Immiscible in water• Low toxicity• High energy density• Cold weather operability• Stable during long‐term storage• Efficient production from a primary energy source
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Drop‐In FuelsDrop‐In Fuels
• Fully compatible with existing fuel infrastructure– Hydrocarbons (alkanes and aromatics)– Possibly butanol
• Are drop in fuels also the “perfect fuel?”
– Close enough
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Three Kinds of BiomassThree Kinds of Biomass
• Lipid‐rich biomass• Lipid‐rich biomass • Lignocellulosic biomass• Waste biomass
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Lignocellulosic FeedstockLignocellulosic Feedstock
• Lignocellulose a three-Lignocellulose a threedimensional polymeric composites formed by plants as structural materialas structural material
• Constituents include:– Cellulose: main source of
glucose (C6 sugar)– Lignin: source of xylose (C5
sugar)g )
• Simple sugars can be liberated from carbohydrate either enzymatically or
Glycosidic bonds
either enzymatically or thermally Cellulose is a polymer of monosaccharides
(glucose)
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Lipid Feedstocks: Nearly hydrocarbons
• Triglycerides: Three fatty acids attached to glycerol b kb f d i il d d i l
Lipid Feedstocks: Nearly hydrocarbons
backbone found in oil seeds and microalgae• Readily converted to pure hydrocarbons via h d ti
CH2
CH2
CH2
CH2
CH2
CH2
CCH2
CH2
OOCH3 CH
hydrogenation
CH2
CCH2
CCH2
CCH2
CCH2
CCH2
C CCCH2
CCH2
OCH3 CH2
CHCH2
CH2
CH2
CH2
CH2
CH2
CCH2
CH2
OOCH3
CH
CHCH2
CCH2
CCH2
CCH2
CCH2
CCH2
C CCCH2
CCH2
OCH3
CH2
CH2
CH2
CH2
CH2
CH2
CCH2
CH2
OOCH3 CH2C
H2
CCH2
CCH2
CCH2
CCH2
CCH2
C CCCH2
CCH2
OCH3
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Lipids vs LignocelluloseLipids vs Lignocellulose
Glycosidic BondsGlucose Unit
Which Kind of Plant Should Deoxygenate Carbohydrate?
O
CH2OH
OHO
OH
OH
O
CH2OH
OHO
OH
OH
OH
OH
O
CH2OH
OHO
OH
OH
Plant No. 2O
OH
O
CH2OH
O
OH
O
CH2OH
O
CH2OH
O
OH
O
CH2OH
CO2Plant No. 1 2H2O
Lipid biosynthesis involves biological deoxygenation of
Lipid
ygcarbohydrates, too!
Cellulose to hydrocarbons
CO2
Source: Nature Medicine 11, 599 – 600, 2005.
Cellulose to hydrocarbons involves deoxygenation of carbohydrate
CO2
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Renewable Fuels Technologies
FEEDSTOCKS TECHNOLOGY BIOFUELS
Renewable Fuels Technologies
FAMETransesterification
Pyrolysis
OILSEEDCROPS
ALGAE
CELLULOSIC BIOMASS FUEL
Pyrolysis
GasificationCatalysisAG WASTES
BIOMASS FUELHYDROCARBONS
TREESGRASSES
ChemicalCatalysis
ALCOHOLSSTARCHGRAINSBiochemical C iSUGARSUGARCANE Conversion
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Thermochemical BiofuelsThermochemical BiofuelsThermochemical BiofuelsThermochemical Biofuels
• The other cellulosic biofuels…• Syngas to biofuels (via gasification)Bi il t bi f l• Bio‐oil to biofuels (via fast pyrolysis)
• Builds upon core competencies at ½ tpd oxygen-blown gasifier at ISU’s Builds upon core competencies at ISU• Gasification and pyrolysis• Catalysis
BioCentury Research Farm
• Catalysis• Novel fermentations• Techno‐economic and life cycle
l i
USDA REE E S it
analysis1/4 tpd fast pyrolyzer at ISU’s BioCentury
Research Farm
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Generalized Thermochemical ProcessGeneralized Thermochemical Process
Depolymerization/ Decomposition
Feedstock
Depolymerization/ Decomposition
Thermolytic
Upgrading
Thermolytic Substrate
Biofuel
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GasificationGasification• Gasification is the thermal decomposition of organic matter
into flammable gasesg
Heating and DryingVolatile gases: CO, CO H H O light
Gas-Solid Reactions Gas-phase Reactions
CO + H2O CO2 + H2
Pyrolysis
HeatH2O
CO2, H2, H2O, light hydrocarbons, tar
CO½ O2 CO
CO + 3H2 CH4 + H2O
½ O22 COCO2
char
Thermal frontpenetrates particle
Porosity increasesH2
H2OCO
CH4
2H2
11
penetrates particleExothermicreactions
Endothermicreactions
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Two Major Gasification OptionsTwo Major Gasification OptionsLow Temperature Gasification
(Bubbling Fluidized Bed)High Temperature Gasification
(Entrained Flow Gasifier)
Syngas biomass
oxygen
Biomass
AshFluidized Bed
1300 °C
Steam/O
Water cooled radiation screen
Oxygenraw syngas and
molten slag
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SyngasSyngas• Syngas consists mostly of CO, H2, CO2, CH4
Composition of syngas (volume percent)Hydrogen Carbon
MonoxideCarbon Dioxide
Methane Nitrogen HHV(MJ/m3)
32 8 2 3 032 48 15 2 3 10.4
• Syngas also contains small amounts of tar, alkali metals, sulfur, nitrogen and chlorine that m st be remo ed before it can benitrogen, and chlorine that must be removed before it can be catalytically upgraded to transportation fuels
Raw Syngas
Particulate Removal
Gasifier
BiofuelBiomass
Tar Removal
Sulfur Removal
Alkali Removal
Catalytic SynthesisOxygen/Steam
Nitrogen Removal
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Gasification EfficiencyGasification Efficiency
• Thermal efficiency - conversion of chemical energy of solid fuel to chemical energy and sensible heat of gaseous productgaseous product– High temperature, high-pressure gasifiers: >95% – Typical biomass gasifiers: 70 - 90%
• Cold gas efficiency – conversion of chemical energy of solid fuel to chemical energy of gaseous product
T i l bi ifi 50 75%– Typical biomass gasifiers: 50-75%
14
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Gasification Opportunities and ChallengesGasification Opportunities and ChallengesGasification Opportunities and ChallengesGasification Opportunities and Challenges
• Advantages – Tolerates relatively dirty biomass feedstock
– Produces uniform intermediate product (syngas)
– Proven method for “cracking the lignocellulosic nut”
– Allows energy integration in biorefinery
• Disadvantages g– Gas cleaning technologies still under development
– Synfuel processing occurs at highSynfuel processing occurs at high pressures ½ tpd gasification plant at ISU’s
BioCentury Research Farm
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Syngas Upgrading to FuelsSyngas Upgrading to FuelsSyngas Upgrading to FuelsSyngas Upgrading to Fuels• Catalytic – performed at moderate temperatures and high pressurestemperatures and high pressures using metal catalysts– Fischer‐Tropsch synthesis to hydrocarbons suitable for fuels
– Methanol synthesis followed by upgrading to gasolineupgrading to gasoline
– Ethanol synthesis
S f t ti f d• Syngas fermentation – performed at ambient temperature and pressure using biocatalystsp g y
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PyrolysisPyrolysis
Definition thermal decomposition ofDefinition – thermal decomposition of carbonaceous material in the absence of oxygenof oxygen
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Py ProductsPy Products
• Gas – non‐condensable gases like carbon dioxide, carbon monoxide, hydrogen
• Solid – mixture of inorganic compounds (ash) and carbonaceous materials (charcoal)
• Liquid – mixture of water and organic compounds known as bio oil recovered from
BioBio--oiloil
bio‐oil recovered from pyrolysis vapors and aerosols (smoke)aerosols (smoke)
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The many faces of pyrolysis
Technology ResidenceTime
Heating Rate Temperature(C)
Predominate Products
The many faces of pyrolysis
Time (C) Products
carbonization days very low 400 charcoal
conventional 5‐30 min low 600 oil, gas, char
gasification 0.5‐5 min moderate >700 gas
Fast pyrolysis 0.5‐5 s very high 650 oil
flash‐liquid <1 s high <650 oil
flash‐gas <1 s high <650 chemicals, gas
ultra <0.5 s very high 1000 chemicals, gas
vacuum 2 30s high <500 oilvacuum 2‐30s high <500 oil
hydro‐pyrolysis <10s high <500 oil
methano‐pyrolysis <10s high <700 chemicals
Mohan D., Pittman C. U. Jr., and Steele P. H. “Pyrolysis of Wood/Biomass for Bio‐oil: A Critical Review” Energy & Fuels, 20, 848‐889 (2006)
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Carbonization (slow pyrolysis)Carbonization (slow pyrolysis)• Charcoal is the carbonaceous
residue obtained from heating bi d dbiomass under oxygen‐starved conditions.
• Charcoal word origin ‐ “the making of coal ”of coal.
• Geological processes that make coal are quite different from those that produce charcoal and properties are Charcoal yields (dry weight basis) quite different.
• Charcoal contains 65% to 90% carbon with the balance being l til tt d i l tt
Kiln Type Charcoal YieldPit 12.5‐30Mound 2 42
y ( y g )for different kinds of batch kilns
volatile matter and mineral matter (ash).
• Antal, Jr., M. J. and Gronli, M. (2003) The Art, Science, and Technology of
Mound 2‐42Brick 12.5‐33Portable Steel (TPI) 18.9‐31.4Concrete (Missouri) 33The Art, Science, and Technology of
Charcoal Production, Ind. Eng. Chem. Res. 42, 1619‐1640
Kammen, D. M., and Lew, D. J. (2005) Review of technologies for the production and use of charcoal, Renewable and Appropriate Energy Laboratory, Berkeley University, March 1, http://rael.berkeley.edu/files/2005/Kammen‐Lew‐Charcoal‐2005.pdf, accessed November 17, 2007.
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The many faces of pyrolysis
Technology ResidenceTime
Heating Rate Temperature(C)
Predominate Products
The many faces of pyrolysis
Time (C) Products
carbonization days very low 400 charcoal
conventional 5‐30 min low 600 oil, gas, char
gasification 0.5‐5 min moderate >700 gas
fast pyrolysis 0.5‐5 s very high 650 oil
flash‐liquid <1 s high <650 oil
flash‐gas <1 s high <650 chemicals, gas
ultra <0.5 s very high 1000 chemicals, gas
vacuum 2 30s high <500 oilvacuum 2‐30s high <500 oil
hydro‐pyrolysis <10s high <500 oil
methano‐pyrolysis <10s high <700 chemicals
Mohan D., Pittman C. U. Jr., and Steele P. H. “Pyrolysis of Wood/Biomass for Bio‐oil: A Critical Review” Energy & Fuels, 20, 848‐889 (2006)
Center for Sustainable Environmental TechnologiesFast Pyrolysisy y
Fast pyrolysis - rapid thermal decomposition of organic compounds in the absence ofin the absence of oxygen to produce predominately liquid product
Biochar
product
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Fast PyrolysisFast Pyrolysis
• Dry feedstock: <10%• Small particles: <3 mm• Moderate temperatures (400‐500 oC)• Short residence times: 0.5 ‐ 2 s• Rapid quenching at the end of the process• Typical yields
Oil: 60 ‐ 70%Char: 12 ‐15%Gas: 13 ‐ 25%
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Bio OilBio‐OilSource: Piskorz, J., et al. (1988) White
SprucePoplarPyrolysis liquid (bio‐oil)
from flash pyrolysis is a Moisture content, wt% 7.0 3.3
Particle size, m (max) 1000 590
Temperature 500 497
Apparent residence time 0 65 0 48
from flash pyrolysis is a low viscosity, dark‐brown fluid with up to 15 to 20% ater Apparent residence time 0.65 0.48
Bio‐oil composition, wt %, m.f.
Saccharides 3.3 2.4
Anhydrosugars 6.5 6.8
15 to 20% water
Anhydrosugars 6.5 6.8
Aldehydes 10.1 14.0
Furans 0.35 ‐‐
Ketones 1.24 1.4
Alcohols 2.0 1.2
Carboxylic acids 11.0 8.5
Water‐Soluble – Total Above 34.5 34.3
Pyrolytic Lignin 20.6 16.2
Unaccounted fraction 11.4 15.2
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Energy EfficiencyEnergy Efficiency
• Conversion to 75 wt‐% bio‐oil translates to energy ffi i f 70%efficiency of 70%
• If carbon used for energy source (process heat or slurried with liquid) then efficiency approaches 94%slurried with liquid) then efficiency approaches 94%
Source: http://www.ensyn.com/info/23102000.htm
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Fast Pyrolysis Opportunities and ChallengesFast Pyrolysis Opportunities and Challenges
• Advantages of bio oil:• Advantages of bio‐oil:– Can be upgraded to drop‐in (hydrocarbon) fuels( y )
– Opportunities for distributed processing
• Disadvantages of bio‐oil– High oxygen and water content makes bio‐oil inferior to
¼ ton per day fast pyrolysis pilot plant at ISU BioCentury Research Farm
High oxygen and water content makes bio oil inferior to petroleum‐derived fuels
– Phase‐separation and polymerization and corrosiveness make long‐term storage difficult
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Applications of Bio‐OilApplications of Bio‐Oil
• Stationary PowerStationary Power• Commodity Chemicals
i l• Transportation Fuels
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And Sugar and Bioasphalt!And Sugar and Bioasphalt!Heavy Ends
Sugar solution (>20 wt%)
WaterWash
Raffinate (mostly phenolicRaffinate (mostly phenolic oligomers derived from lignin)
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BiocharBiochar• Carbonaceous residue from pyrolysis of biomasspyrolysis of biomass
• Yields range from 5‐40% of biomass depending upon processbiomass depending upon process conditions
• Fine, porous structure, p• Several potential applications, the most intriguing being dual g g guse as soil amendment and carbon sequestration agent
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Terra Preta: Anthropogenic Soils from Biochar
Terra Preta Oxisol
Terra Preta: Anthropogenic Soils from Biochar
• Created hundreds of years yago by pre‐Colombian inhabitants of Amazon BasinBasin
• Result of slash and char agriculture
• Much higher levels of soil organic carbonF d i h Applied to the land, biochar serves as
both soil amendment and carbon sequestration agent
• Far more productive than undisturbed oxisol soils
Glaser et al. 2001. Naturwissenschaften (2001) 88:37–41
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Biochar’s ImpactBiochar s Impact• Biochar increases soil cation exchange
capacity (CEC), holding ammonium ions
Increases:Cation Exchange capacity (CEC), holding ammonium ions
(NH4+) and other cations in the soil
• Biochar adsorbs soil organic matter which 1
gCapacitySoil Organic MatterDrainage
contains plant‐available organic nitrogen1
• Biochar’s low bulk density increases soil aeration and water drainage, lessening the
gAeration
Dg , glikelihood of denitrification (NO3
‐ N2O N2) and associated N2O emissions2
• Addition of biochar has been shown to
Decreases:Soil Bulk DensityDenitrification
• Addition of biochar has been shown to decrease nutrient leaching (nitrate, phosphate, cations) from manure amendments3
N2O EmissionsNutrient Leaching
amendments1. Laird, D. A., Agron J 2008, 100, (1), 178-181.2. Rogovska, et al. North American Biochar Conference, Boulder, CO, Aug 2009.3. Laird, et al. 2008 GSA-SSSA-ASA-CSA Joint Meeting, Houston, TX, Oct 2008.
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GHG Impacts of Soil Application of BiocharIncreased CO2emissions due to enhanced
Competition between food and biomass
Increased CO2emissions due to enhanced
Competition between food and biomass
GHG Impacts of Soil Application of Biochar
to enhanced soil microbial respiration
and biomass crops may increase land under cultivation.
to enhanced soil microbial respiration
and biomass crops may increase land under cultivation.
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Reduce N2O emissions from soils
Reduce CO2emissions due to decreased
Increase C input to soil due to
Increase C sequestration in soils
Increased yields may decrease the
Reduce CO2emissions due to bio-oil
Reduce N2O emissions from soils
Reduce CO2emissions due to decreased
Increase C input to soil due to
Increase C sequestration in soils
Increased yields may decrease the
Reduce CO2emissions due to bio-oil
due to better soil aeration
use of lime and fertilizer
enhanced plant growth
(Biochar C is very stable)
amount of land needed to grow food.
displacing fossil fuel
due to better soil aeration
use of lime and fertilizer
enhanced plant growth
(Biochar C is very stable)
amount of land needed to grow food.
displacing fossil fuel
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Proof‐of‐Concept: Terra Preta in BrazilProof‐of‐Concept: Terra Preta in Brazil
Terra Preta OxisolTerra Preta Oxisol
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Lovelock on BiocharLovelock on Biochar
“There is one way we could save ourselves and that is through the massive burial ofthrough the massive burial of charcoal. It would mean farmers turning all theirfarmers turning all their agricultural waste…into non‐biodegradable charcoal, and
James Lovelock in an otherwise pessimistic
burying it in the soil.” interview with New Scientist Magazine (January 2009) on our
t f h lti l b lprospects for halting global climate change
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ISU Facilities to Support Thermochemical ResearchISU Facilities to Support Thermochemical Research
Micropyrolyzers & bio-oil analysis
Lab-scale pyrolyzers and gasifiers Batch and fixed bed
catalytic upgrading reactors
ISU Biorenewables Laboratory
Quarter-ton/day pilot plant fast pyrolyzer Half-ton/day pilot plant y p poxygen-blown gasifier
ISU BioCentury Research Farm