Bioenergy Symposium Takehara

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Biomass GasificationBiomass Gasificationin ain a

Dry Grind Ethanol Facility:Dry Grind Ethanol Facility:

Benefits and ChallengesBenefits and Challenges

Purdue 2006 Bioenergy SymposiumPurdue 2006 Bioenergy Symposium

Feb. 23, 2006Feb. 23, 2006

Don TakeharaDon Takehara -- Taylor UniversityTaylor University

Mitch MillerMitch Miller -- Central Indiana EthanolCentral Indiana EthanolRobert BrownRobert Brown -- Iowa State UniversityIowa State University

JasonJason JerkeJerke -- Chippewa Valley Ethanol CompanyChippewa Valley Ethanol Company



Fluidized Bed Biomass GasifierFluidized Bed Biomass Gasifier

FluidizedBed ofSand

(750oC)

Biomass

Air

Producer or Syn GasH2, CON2, CO2, CH4,

Hydrocarbons

Note: Fluidized bed is onlyone possible type ofreactor



Biomass Gasification: Reactions

Two Simultaneous Reaction Types

H H H H| | | |

Pyrolysis: -C-C-C-C- + Heat H2+ CH4 + hydrocarbons (endothermic)

| | | |

H H H H

Combustion: C + O2 CO2 + Heat (exothermic)

Note: 1. Actual reaction scheme is very complicated2. C + H2O + heat CO + H2 is a source of CO and H2

3. CO + H2O CO2 + H2 is a source of H2 (water-gas shift)



Why Gasification?Why Gasification?

Biomass

CO + H2

COMBUSTION CO2 + H2O

GASIFICATIONWATER-GAS

SHIFT

CATALYSIS/BIOCATALYSIS

H2 + CO2

Organic acids

AlcoholsEstersHydrocarbons

THERMAL

ENERGY

FUELCELLS

FUELS &CHEMICALS

Air

Steam

ELECTRICALENERGY



Whole Crop BiorefineryWhole Crop Biorefinery

CO 2 Starch Enzymes

Fermenter

CookerGrain

Milling

Distillation

Ethanol &

Fermentation products

DDGS

Separation

Corn Oil

Water

Starch Sugar

Whole

Corn Crop

CO2Cellulose Enzymes

Fermenter

Saccharification

Corn Stover

Preprocessing

Lignin

Holocellulose hydrolyzed to sugars



What to Do With the Byproducts of Biorefinery?What to Do With the Byproducts of Biorefinery?

Gasifier

Syngas Gas Cleaning Catalytic Reactor

Fuels and chemicals

Air

CO2

Byproductsgasified to

CO and H2

Converts gasesinto hydrocarbons

Removes,particles, tar,contaminants

Lignin

Heat Recovery



Drymill Ethanol ProcessDrymill Ethanol Process



Ethanol ProductionEthanol Production – – Energy CostsEnergy Costs

$8/MM Btu for Natural Gas

$0.24/gal of Ethanol (30,000 Btu/gal)

$11.5 million/yr for Central Indiana Ethanol(48M gal/yr capacity)

Reducing natural gas Cost Savings!



Biomass Gasification Replaces Natural GasBiomass Gasification Replaces Natural Gas

Biomass

Gasifier(800oC)

Distillers GrainOther Biomass

Wood

Corn Stover (Stalks)Etc.

Producer GasH

2, CO

N2, CO2, CH4,hydrocarbons

Natural Gas

EthanolPlant



Savings Via Distillers GrainsSavings Via Distillers Grains

GasificationGasification

$4.0$5.0$6.0$9/MMBtu Nat. Gas

$2.5$3.5$4.5$8/MMBtu Nat. Gas

$1.1$2.1$3.2$7/MMBtu Nat. Gas

-$0.4$0.7$1.7$6/MMBtu Nat. Gas

-$1.8 M/yr-$0.8 M/yr$0.2 M/yr$5/MMBtu Nat. Gas

$90/tonDistillersGrains



Savings in $M/yr for Central Indiana Ethanol Plant (48M gal/yr)

(Capital costs not included)



Gasification Hurdles in theGasification Hurdles in the

Ethanol IndustryEthanol Industry

Process IntegrationProcess Integration

Feedstock HandlingFeedstock Handling

Capital CostCapital CostPolicy/PermittingPolicy/Permitting



Process IntegrationProcess Integration

Biomass harvest, storage andsupply systems needed

Uninterrupted feedstock neededto avoid process upsets.

Dedicated boiler and oxidationsystems to handle increasedgas flow through the burner and

system.

Btu/Volume:Btu/Volume:

Producer Gas < Natural GasProducer Gas < Natural Gas

Gas cleanup technologies beingdeveloped

(Integrated systems –thermal

oxidation and ash removal)

Tars & ash in producer gasEquipment fouling

SolutionSolutionProblemProblem



Capital CostCapital Cost

$12M$12M--15M gasification system needed for a typical15M gasification system needed for a typicalethanol facilityethanol facility

– – Central Indiana Ethanol is a $64M PlantCentral Indiana Ethanol is a $64M Plant

The 2005 energy bill provides significant tax relief.The 2005 energy bill provides significant tax relief.



Feedstock HandlingFeedstock HandlingProblemsProblems

Typical Ethanol production facility (50M gal/yr) wouldTypical Ethanol production facility (50M gal/yr) wouldneed ~350 tons/day of dry biomassneed ~350 tons/day of dry biomass

No storage techniques available for dry biomass on thatNo storage techniques available for dry biomass on that

scale (wood waste is an exception)scale (wood waste is an exception)

Feeding corn stover into a reactor above atmosphericFeeding corn stover into a reactor above atmosphericpressurepressure

SolutionsSolutionsEthanol plants can utilize inEthanol plants can utilize in--house feedstock such ashouse feedstock such as

syrup and DDGS.syrup and DDGS.

Innovation is key to making large scale biomassInnovation is key to making large scale biomass

handling and storage commercially viable.handling and storage commercially viable.



Policy/PermittingPolicy/PermittingPolicy is key for implementing new concepts inPolicy is key for implementing new concepts in

industry.industry.Biomass production and/or utilization incentivesBiomass production and/or utilization incentivesneeded on the state and federal levels.needed on the state and federal levels.

Policy makers need to be involved.Policy makers need to be involved.Air permitting is new territory because stateAir permitting is new territory because statepollution control agencies deal with coal orpollution control agencies deal with coal ornatural gas combustion.natural gas combustion.

Months to years needed to permit newMonths to years needed to permit newgasification systems on an industrial scale.gasification systems on an industrial scale.



Technical Barriers

FeedProcessing

& Handling

Gasification&

Pyrolysis

GasConditioning

& Separation

SyngasUtilization

Heat& Power

Generation

Hydrogen

& Bioproducts

Fuels

& Chemicals

Thermal Energy

Electricity

Biomass

(Crops)

BiorefineryByproducts

Source: National Renewable Energy Laboratory

3 Major Technical Challenges1. Producer Gas Contaminants2. Incomplete Carbon Conversion3. Agglomeration in Fluidized Bed



Producer Gas ContaminantsProducer Gas Contaminants(Unique to Biomass Gasification)(Unique to Biomass Gasification)

Alkali CompoundsAlkali Compounds

(from Biomass)(from Biomass) – – Solids: Ash ParticulatesSolids: Ash Particulates

– – GasesGasesDownstream DepositionDownstream Deposition

Char ParticulatesChar Particulates((unreactedunreacted biomass)biomass)

TarTar – – Hydrocarbons, M.W. > BenzeneHydrocarbons, M.W. > Benzene

FluidizedBed

Air

Biomass

Impact on Downstream Technologies



End Use Impact of ContaminantsEnd Use Impact of Contaminants

YesYes

YesYes

NoNo

NoNo

SulfurSulfur

YesYesYesYesYesYesYesYesFuel CellsFuel Cells

YesYesYesYesYesYesYesYesFuels &Fuels &

ChemicalsChemicals

NoNoYesYesYesYesYesYesElectricalElectricalEnergyEnergy

(turbine)(turbine)

NoNoMinimalMinimalMinimalMinimalMinimalMinimalThermalThermal

EnergyEnergy

CO/HCO/H22

RatioRatioTarTarCharCharAlkaliAlkali

CompoundCompound

Difficulty ofImplementingBiomassGasification



Elutriation of Char ParticlesChar Formation

H2, CO, CO2, CH4, hydrocarbons

Porosity increases

Weight decreasesLess reactive with time

HeatO2

Reduced Conversion of Carbon

Elutriation of Char

FluidizedBed

Air

Biomass

CharProducer Gas

Terminal Velocity



Elutriation Rate MeasurementElutriation Rate Measurement

Laser MethodLaser Method

TaylorTaylor – – Iowa State CollaborationIowa State Collaboration

Measurement is essentialMeasurement is essential – – Understand elutriationUnderstand elutriation

– – Increase Carbon conversionIncrease Carbon conversion

Laser System for measuring particle concentration

Io I



Laser Method: Initial ResultsLaser Method: Initial Results

Particle Concentration (g/m3

)

I/Io

Response vs Concentration



Agglomeration in Fluidized Bed

AlkaliCompounds

BiomassParticle

FluidizedBed

Particle

Glassy film

Agglomeration of Particles

Alkali Compounds: K (fertilizer), Na, SiO2 (soil), Ca, Mg, etc.

Fluidization Ceases & Reactor Fails



TaylorTaylor--Iowa State Pressure Fluctuation StudyIowa State Pressure Fluctuation Study

4 in.

FluidizedBed ofGlassBeads(25oC)

Air

(Vary Flow Rate)

Pressure Transducer

ClearPlexiglasReactor

(VisualObservation)

Flow Meter

Measure P vs time (Pressure Fluctuations)

Cold Flow ModelMimics Reactor

Hydrodynamics



Taylor Cold Flow ModelTaylor Cold Flow Model GasifierGasifier



Pressure Fluctuation in BedPressure Fluctuation in Bed

0.05 psi fluctuations

Is it meaningful?

Pressure vs. Time

2750

2800

2850

2900

2950

3000

3050

3100

3150

3200

3250

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

time (sec)

P r e s s

u r e

( p a s c a l s )



Bode Plot AnalysisBode Plot AnalysisBode Plot for Pressure Fluctuations

40

50

6070

80

90

100

110120

130

140

0 0.5 1 1.5 2 2.5

log (frequency)

2 0 * l o g ( P o

w e r S p e c t r a l D e n s i t y

4.3 cfm

7.0 cfm

9.75 cfm

Fluidized Beds yield characteristic Bode PlotsFluidized Beds yield characteristic Bode Plots

Bode Plots correlate with Hydrodynamics?Bode Plots correlate with Hydrodynamics?

Potential diagnostic tool for bed agglomerationPotential diagnostic tool for bed agglomeration



Future ResearchFuture Research

Background:Background:

– – ScaleScale--up from lab to commercial reactor isup from lab to commercial reactor is

difficultdifficult

– – Mathematical model would help significantlyMathematical model would help significantly

CFD (Computational Fluid Dynamics) is availableCFD (Computational Fluid Dynamics) is available

Issue:Issue:

– – CFD model has not been compared toCFD model has not been compared to

Experimental DataExperimental DataSolution:Solution:

– – Cold Flow ModelCold Flow Model

Gather data and compare to CFD resultsGather data and compare to CFD results



Variables to CompareVariables to Compare

CFD Model

Pressure Fluctuationsvs

Flow Rate

Elutriation Ratevs

Flow Rate

Other Variables?

Cold Flow Model

Pressure Fluctuationsvs

Flow Rate

Elutriation Ratevs

Flow Rate

Other Variables?



AcknowledgmentsAcknowledgments

Taylor UniversityTaylor University – – funding/encouragementfunding/encouragement

Lilly EndowmentLilly Endowment

Taylor StudentsTaylor Students – – Jonathan HamiltonJonathan Hamilton

– – Derek SchmidtDerek Schmidt

– – Joe ManierJoe Manier – – Mark BurtnessMark Burtness

– – John BurtnessJohn Burtness

– – Leslie DavisLeslie Davis

– – Kelly IsaacsonKelly Isaacson

Jay BerryJay Berry

Steve BerrySteve Berry

Documents

Bioenergy Symposium Takehara