thermochemical conversion of biomass to fuel.cenusa brown 5-25-12

Center for Sustainable Environmental Technologies

The Thermochemical Option

Robert C. BrownRobert C. Brown


Iowa State UniversityIowa State University

CenUSA WebinarMay 25, 2012


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


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


Three Kinds of BiomassThree Kinds of Biomass

• Lipid‐rich biomass• Lipid‐rich biomass • Lignocellulosic biomass• Waste biomass


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)


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


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


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


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


Generalized Thermochemical ProcessGeneralized Thermochemical Process

Depolymerization/ Decomposition

Feedstock

Depolymerization/ Decomposition

Thermolytic

Upgrading

Thermolytic Substrate

Biofuel


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


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


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


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


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


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


PyrolysisPyrolysis

Definition thermal decomposition ofDefinition – thermal decomposition of carbonaceous material in the absence of oxygenof oxygen


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)


The many faces of pyrolysis

Technology ResidenceTime

Heating Rate Temperature(C)

Predominate Products


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)


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.



Technology ResidenceTime

Heating Rate Temperature(C)

Predominate Products


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


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%


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


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


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


Applications of Bio‐OilApplications of Bio‐Oil

• Stationary PowerStationary Power• Commodity Chemicals

i l• Transportation Fuels


And Sugar and Bioasphalt!And Sugar and Bioasphalt!Heavy Ends

Sugar solution (>20 wt%)

WaterWash

Raffinate (mostly phenolicRaffinate (mostly phenolic oligomers derived from lignin)


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


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


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.


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.

+

0

+

00

_

0

_

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


Proof‐of‐Concept: Terra Preta in BrazilProof‐of‐Concept: Terra Preta in Brazil

Terra Preta OxisolTerra Preta Oxisol


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


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

thermochemical conversion of biomass to fuel.cenusa brown 5-25-12

Technology

o heat

h2o co2

typical biomass gasifiers

perfect energy carrier

h2o lighto

transportation fuel

kind of plant

hydrocarbons triglycerides