biochar production: technology options and perspectives on … · 2011-07-07 · biochar...

Biochar Production: Technology options and

perspectives on large scale production and use

of liquids and syngas

Cordner Peacocke

Conversion And Resource Evaluation Ltd.

Holywood, Northern Ireland, BT18 9BY

Tel: +44 2890397811

E: cpeacocke@care.demon.co.uk

http://www.care.demon.co.uk

May 2011

2

Scope of presentation

• Pyrolysis review: UK Pyrolysis examples

• Process Parameters in Pyrolysis

• Power Generation in Pyrolysis – power generation

comparison

• Uses of Byproducts – liquids and syngas

• Gas Engine Use

• Large Scale technology deployment: issues

• Conclusions

3

Technology classes

• Basic technology: simple charcoal production for

small scale production [~<100 kg/d]

• Intermediate technology: larger scale char (possible

energy or chemicals) production for commercial sale

[<1 t/d, > 100 kg/d]

• Advanced technology: product(s) and energy

production, energy integrated process, environmental compliance, commercial with guarantees [ >1 t/d]

Degree of development based on use of byproducts, environmental

compliance and process integration (energy efficiency)

4

Thermal Bio-Energy Industry

Context:

• 250+ "commercial" pyrolysis companies worldwide

• 300+ "commercial" gasification companies worldwide

• Only 10 companies have pyrolysis + power generation

using clean biomass derived syngas experience worldwide

UK

• ~17 pyrolysis companies

• ~20 gasification companies, agents, licensees

• 3 companies with syngas + gas engine experience

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UK Pyrolysis plants: selection

• 2G BioPower Ltd. [Envergent technology]

• PurePower, Huntingdon: 4 MWe

• EPI, Mitcham: 1 t/h

• University of Aberystwyth, Aberystwyth : 500 kg/d output biochar unit

• Hudol, Cardiff: 1.5 t/h demo/R&D unit

• NewEarth, Canforth: 5 MWe [5 x 1MWe modules]

• First London Power, London: 0.5 t/h demonstrator

• GEM, Scarborough, 1.5 t/h input, 1 MWe output

• Biomass Engineering Ltd., Newton-le-Willows: 250 kg/h fluid bed fast pyrolysis for liquids unit [dormant]

• Wellman Process Engineering Ltd., Oldbury 250 kg/h fluid bed fast pyrolysis for liquids – [dormant]

• Many R&D units available in universities;

• Small-scale systems; regional charcoal producers

6

Basic: Numerous designs

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What we need to move away from..

Health and Safety Issues:

CO exposure [LTEL 30ppm, STEL

200 ppm]

Pyrolysis aerosols and ''tars''

Dust inhalation [wood dust 10 mg/m3,

char [nuisance dust] 15 mg/m3]

Burns

Good PPE

Handling and Transportation:

Pyrophoric Char – air exposure to

minimise

Dust exposure

Good housekeeping and

procedures needed at all stages

8

Intermediate: University of Aberystwyth

• 500 kg/day• Batch process

• In operation

9

Advanced:PurePower, Huntingdon (PTE, South Africa)

• 4 MWe output

• 1 Plant in UK, others in Europe planned

• Status: uncertain

10

Advanced: EPi, Mitcham, London

• 1 MWe net output

• ~8000 t/y C&I wastes

• ~1000 t/y char for various uses

• Char and energy production

• Power generation

from April 2011

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Advanced: Hudol, 4 t/h

• Pilot plant

• Operates on a range of wastes, including oils

• Process temperature of 500°C in zone I, 900°C in

zone II to yield syngas

• Gas engine experience

• Projects delivered through PTE, South Africa.

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Advanced: GEM (Yorwaste), 1.5 t/h

• MSW feedstock

• Plant only reached 60% of capacity

• Generated 242 MWh on gas engines

• 70 t of ''char'' produced

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Process parameters in pyrolysis for char

Biomass related [controllable to a limited extent]• biomass particle size,• biomass particle shape,• biomass pretreatment [additives/ash content and composition, moisture,

chemical composition,• biomass density,• biomass properties [specific heat capacity, thermal conductivity,

permeability],• intrinsic properties of the biomass [lignin, cellulose, hemi-cellulose

contents].

Reactor operation [substantially controllable]• reactor temperature [not necessarily the temperature at which pyrolysis

occurs],• biomass heating rate and heat transfer,• pressure [hydrostatic and mechanical],• biomass decomposition temperature [f(intrinsic properties, ash compn),• gaseous [reactor] environment.• gas/vapour product reactor residence time,• gas/vapour product temperature,

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How temperature affects Decomposition: Cellulose

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5Time [s]

Fraction

Cellulose

Active

Char

Tar

Gas

Fraction

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5

Time [s]

400°C450°C

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Char output v’s reactor temperature

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

400 450 500 550 600 650 700 800

Reactor Temperature [°C]

Char

output

[t/h]

0

1

2

3

4

5

6

Biomass

throughput

[t/h]

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Pyrolysis Liquids and Syngas

• Comprise 65%+ of the products in mass and energy terms

• Liquids multiple uses:

– Chemicals [acetic acid, hydroxyacetaldehyde, levoglucosan, glycolaldehyde],

– Products synthesis: slow release fertilisers, resins, preservatives, soil additive [lignin fraction],

– fuels & liquids upgradable to hydrocarbons.

• Syngas: multiple uses:

– Cleaned for power generation [HHV up to 23 MJ/kg],

– Burnt for process heat [pyrolyser or dryer],

– Used after catalytic shift for FT synthesis to diesel equivalent.

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Why consider byproduct use?

Liquids use:

– Chemical and product applications possible for liquids

– Very limited experience in liquids combustion for power in the UK � consider cracking to syngas,

– Disposal cost and environmental issues [low pH, high COD]

Syngas use:

– for heating the pyrolysis process,

– burnt for process heat and/or drying,

– cleaned up and burnt for power in a gas engine or turbine [2xROCS @ £36.99/ROC + base price = ~£100-160/MWh],

– Chemicals or liquids fuel synthesis [FT synthesis]

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• “Tar” definition – numerous “definitions” in the

literature

• Engines susceptible to “tars” – organic compounds in

the gas – range of definitions, but CEN TC BT/TF 143 defines “tar” as:

generic (unspecific) term for entity of all organic compounds present in the gasification product gas

excluding gaseous hydrocarbons (C1 through C6)

• Engine are highly susceptible to ‘’particulates’’ –

should be avoided at all costs.

Engines – tars and particulates

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Engines – key areas

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Gas engines: Specifications for Syngas

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Technology to electricity efficiencies

0%

5%

10%

15%

20%

25%

30%

35%

40%

0 5 10 15 20

Net System Capacity, MWe

SystemEfficiency[%LHV]

FPyrEng

GasEng

IGCC

Comb

DDGasEngSPyrEng

SPyrST

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Electricity Generation Cost Comparison

TotalPlant CostMUS$/MWe

0

2.5

4.2

5.6

7.0

8.5

0 5 10 15 20

Net System Capacity, MWe

FPyrEng

GasEng

IGCC

Comb

Combustion plant costs areestablished or 100th plant costs.All other are 1st plant costs

DDGasEng

1.4

HTPyrEng

HTPyrST

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0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

0 5 10 15 20 25 30 35 40 45 50

Thermal Input [MWth]

Electrical

Efficiency [%]

Comparison of Prime Mover Efficiencies

Steamcycle

Gasengine

OrganicRankineCycle

Gas turbine

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Commercial Biochar UK

• Identified 20+ claimed commercial producers of biochar worldwide [exc. standard charcoal retailers]

• Wide price ranges from £100/t to over £16,000/t, depending on quantities and geographical location

• Few companies with a detailed product specification

• UK Commercial biochar examples:

– Black Gold – Nutrichar: £4.99 for 300g

– Carbon Gold – Grochar: £9.95 for 1.4 kg

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Technology Developments/observations

• Lower efficiency, but for large scale, pyrolysis + steam cycle makes sense cost wise and reliability wise – and from an investor perspective,

• Feed handling: systems are not omnivorous and care should be taken in their design [drying integration],

• Pyrolysis technology is mature technology – limited scope for further developments,

• DSEAR [Dangerous Substances and Explosive Atmospheres Regulations ], ATEX and other Directives to comply with,

• Gas cleaning experience: syngas upgrading or cleaning for gas engines: more experience needed and better monitoring [tars and particulates]

• Gas engines: available from GE Jenbacher, Guascor, Caterpillar – very tight specifications

• Environmental compliance achievable and a necessity.

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Despite their best efforts….

2011 Grimsvotn volcano in Vatnajokull National Park

2010 Eyjafjallajökull