biochar production: technology options and perspectives on … · 2011-07-07 · biochar...
TRANSCRIPT
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
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
5
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
7
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
11
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.
12
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
13
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,
14
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
15
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]
16
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.
17
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]
18
• “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
19
Engines – key areas
20
Gas engines: Specifications for Syngas
21
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
22
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
23
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
24
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
25
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.
26
Despite their best efforts….
2011 Grimsvotn volcano in Vatnajokull National Park
2010 Eyjafjallajökull