4/5/2009

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Biomass Fast Pyrolysis

Dr. Christopher M. Saffron

Department of Biosystems and Agricultural Engineering Department of Biosystems and Agricultural Engineering

Department of Forestry

Michigan Agri-Energy Conference

March 30th, 2009

Overview

• What is pyrolysis?

• Technology

• Pyrolysis metrics

• Upgrading

• Distributed 

processing

• Industrial activity
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What is pyrolysis?

• Heat addition to biomass in the absence of oxygen to 

temperatures ranging from 400°C to 1000°C

• One step in gasification

• Products of biomass pyrolysis are a 

– Solid (char)

– Liquid (upon condensation with cooling)

– Gas (light hydrocarbons and carbon oxides)

• Higher temperatures and longer residence times favor 

gas production

• Lower temperatures and longer residence times favor 

char production

• Moderate temperatures and short residence times favor 

liquid production

Pyrolysis

• Slow pyrolysis

– a k a carbonization a.k.a. carbonization

– Used for producing charcoal

• Fast pyrolysis

– Used for fuel production

– High heating rates

– Low retention times

– Greater liquid, i.e. ‘bio-oil’ yield

– Co-products

• bio-char 

• combustible gas

http://www.biochar-international.org/
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Bio-oil

Steele, P.; Ingram, L. Current and Future Products for Pyrolysis 

Oils. Dept. of Forest Products. Mississippi State University

Components of Biomass (Plant Cell Wall Polymers)

Cellulose: Polymer containing glucose-same sugar as in starch

Much more resistant to degradation than starch 

Hemicellulose: Complex polymers 

Lignin: Plastic-like 

polymer; provides 

structure, but inhibits 

wall breakdown.

Residues can be 

burned for energy

found in cell walls; diverse in sugar 

composition.

1. Xyloglucan

2. Glucomannan

3. Arabinoxylan

4. Mixed-linkage glucan

Ragauskas et al. (2006) Science 311:484 The path forward for biofuels and biomaterials.
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Products of cellulose pyrolysis

levoglucosenone cellulose

D-glucose

hydroxymethylfurfural

levoglucosan

O

O

OH

HO OH

Products of hemicellulose pyrolysis

acetic acid

arabinoxylan

1,5-anhydrofuranoses

2-furfural
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sinapyl alcohol

Products of lignin pyrolysis

coniferyl alcohol

p coumaryl alcohol

syringol

pyrogallol

p-coumaryl alcohol

lignin

gallic acid

guaiacol

vanillin

py g

Bio-oil composition

• Hundreds to thousands of compounds

• Compounds are oxygenated

– Nt t d d t l Not at reduced as petroleum-b df l ased fuels

• Chemical classes identified in bio-oil

– Aldehydes

– Alcohols

– Carbohydrates

– Furans

– Ketones

– Phenolics

– others

• Bio-oil composition is variable

– Interspecies variability

– Intraspecies variability

– Operational variability
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Bio-oil production

biomass bio-oil

Dryer Grinder Reactor Cyclone Condenser

combustible 

gas

Combustion char

heat heat

Adapted from Bridgwater, A. V.; Peacocke, G. V. C. Renewable 

Sustainable Energy Rev. 2000, 4, 1.

gas

Technology

• Reactor configuration

– Fluidized bed 

– Circulating fluidized bed 

– Rotating cone 

– Entrained flow

– Ablative

– Auger 
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Bubbling fluidized bed

pyrolysis gas

biomass sand char

gas & 

char

gas bubble

hot gas

distributor

Circulating fluidized bed

pyrolysis gas & 

char char

sand

biomass

gas 

char 

gas bubble sand

hot gas

distributor

sand return
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Rotating cone

Biomass 

& sand

Pyrolysis 

gas

heater

sand

char

sand

Entrained flow

Biomass 

& gas

Furnace 

heater

Gas & 

char
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Ablation

biomass gas

blades

pyrolysis gas

char

heat

Auger- or screw-driven reactors

2

N2

N2

1

5

6 7

8

10

Gas

3

4

9

M

N2

1

5

6 7

8

10

Gas

3

4

9

M

10

Char Bio-oil

Bench-scale screw-conveyor pyrolysis reactor with downstream product recovery to 

be constructed for use in the MSU Pyrolysis Laboratory. 1. screw motor, 2. feed 

hopper, 3. feed valve, 4. screw conveyor, 5. pyrolysis reactor, 6. cooler, 7. heat 

source, 8. cyclone, 9. char collector, 10. bio-oil chiller.
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Performance metrics

• Bio-oil yield

– Liq y uidield 60 - 80% ( ) w/w

• Bio-oil properties

– Heating value = 16 – 20 MJ /kg

– Viscosity = 40 - 100 cP

– Specific gravity = 1.20

– pH = 2.5

– Moisture content 15 – 30% (w/w)

• Energy requirement Energy requirement

– About 15% of the energy is biomass required to heat the 

pyrolysis reactor

– This energy can be supplied by combusting the non-condensed 

gas and char

Upgrading

• Due to oxygen content in bio-oil:

– Lower heating value

– Reactive carbonyl and carboxylate 

functionality lead to polymerization

– Organic acids reduce pH and increase 

corrosiveness

• Bio-oil requires upgrading before use as a 

liquid transportation fuel
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Upgrading technologies

• Catalytic cracking

– Most de y used p ocess o co e t g t e ea y widely used process for converting the heavy

fraction of petroleum into hydrocarbons (e.g. 

gasoline)

• Hydrotreating

– More expensive than cracking

– Addition of H2 for reduction of bio-oil components

– Increase bio-oil heating value

– U C seso-M Ni o or Ni-M tl t o as catalysts

• Addition of methanol

• Emulsification with diesel fuel

Distributed processing

• Regional 

Biomass

Processing 

Centers 

(RBPCs)

• Advanced 

combines

• Mobile 

technology

http://www.agri-therm.com/solution.html
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Industrial activity

• Dynamotive*

– Biomass py y rol sis

• Bio-oil used for power generation at West Lorne, Ontario

– 2.5 MW cogeneration plant

• 66,000 dtpy of biomass when fully operational at Guelph, Ontario

• Ensyn†

– Biomass pyrolysis 

• Bio-oil used for heat, replacing #2 to #6 heating oil

• Stationary power

• Use bio-oil as feedstock to existing refineries

• Food flavors with Red Arrow Products

• Pyrolytic lignin to make phenol-formaldehyde resins for OSB

• Extraction of pyrolytic lignin for conversion to BTX chemicals

*http://www.dynamotive.com/

† http://www.ensyn.com/

Industrial activity

• Riverside Technologies, Inc.*

– Pyrolysis of scrap tires

• Carbon black for reinforcing rubber

• Oil for further refinement

• Gas for combustion

• Scrap steel from belts in tires

• Ecovolve†

– Electricity production

– Project management, equipment procurement

– Carbon negative technology

• Agri-Therm^

– Canadian Company converting agricultural residues into bio-oil

– Fluidized-bed reactor on a mobile pyrolysis plant

*http://www.rtiworldwide.com/products.html

† http://www.ecovolve.com/

^http://www.agri-therm.com/
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Questions