torrefaction - eskom · 125.21-million tons of coal 224 785 gwh of electricity ... loesche silo...
TRANSCRIPT
DNV GL © 2013 March 19th, 2014 SAFER, SMARTER, GREENER DNV GL © 2013 POWERGEN AFRICA
March 19th, 2014
Mark Beekes, Matshela Koko
ENERGY
Torrefaction
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A feasible solution for South African co-firing options
DNV GL © 2013 March 19th, 2014
Contents
Background
Levelized cost of co-firing options
Fuel specification of torrefied biomass
Impact of co-firing of torrefied biomass on plant operations
Selection and risk assessment of torrefaction technology
Next steps
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DNV GL © 2013 March 19th, 2014
Background
Zuma speaks of 'greening SA economy' at COP17
reducing its absolute emissions by 10% by 2025
2011/2012, Eskom
231.9-million tons of carbon dioxide emissions
125.21-million tons of coal
224 785 GWh of electricity
Co-firing
Estimated potential to displace about 10% of coal
20 million tons of biomass
First step: Arnot power station -> torrefied biomass
130,000 tonnes of raw biomass -> 60,000 tonnes torrefied pellets
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Arnot Power Station, Eskom
DNV GL © 2013 March 19th, 2014
Levelized cost of co-firing options
Coal to biomass cost recovery gap
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755706
633610
0
100
200
300
400
500
600
700
800
900
white pellets
(co-milling)
white pellets
(hammer milling)
black pellets
(silos)
black pellets
(no silos)
Cost
rec
over
y g
ap (
ZA
R/M
Wh g
reen
)
DNV GL © 2013 March 19th, 2014
Biomass and fuel specification
Biomass analysis
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1) New draft
Parameter Unit Range Method Alternative
standard
Moisture wt% <10% for pellets ISO 589 Method B 1) EN 14774
Calorific value MJ/kg Wood pellet 16-18 ISO 1928 1) EN14918
Ash % Max 3% ISO 1171 (5500C) 1) EN14775
Volatile matter % EN 15148
Hydrogen % 1) EN 15104
Carbon % 1) EN 15104
Nitrogen % Max. 1 1) EN 15104
Sulphur % Max. 0,05 ISO 351 EN 15289
Heavy metals mg/kg EN 15297
Ash melting DT 0C Min. 1100 CEN/TS 15370-1
DNV GL © 2013 March 19th, 2014
Torrefied biomass specification
Torrefied biomass specification
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Parameter Unit Range Comments
Calorific value MJ/kg 20 - 24
Ash % 2-5%
Bulk density (pellets) kg/m3 650 - 800 As high as possible
Bulk density (briquettes) % 500 - 650 Small briquettes
Fixed carbon % 22-35
DNV GL © 2013 March 19th, 2014
Biomass and fuel specification
Sample preparation according to
– CEN 14780,
– CEN 14418
– NTA 8202
No standards for torrefied biomass yet
– not expected before 2015
– torrefaction technology/conditions dependent
First Round Robin for torrefied biomass performed
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Left-overs at Safcol plantations
DNV GL © 2013 March 19th, 2014
Operational study torrefied biomass firing at Arnot Power Station
Summary of conclusions: - 10% co-firing: effects on unit minor
- 20, 30% co-firing: attention required
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Storage Handling Performance
source: steel-silos
source: loesche
silo storage is preferred above open storage to avoid dust problems
mill performance is critical item: • by increased power
consumption • particle size • temperature of
primary air
• unit efficiency: flue gas temperature and burnout require attention
• slight derate may be possible
DNV GL © 2013 March 19th, 2014
Selection and risk assessment of torrefaction technology
Developer G
Developer E
Developer D
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Gross list First selection Site visits Second
selection
> 30 developers Andritz
Areva
Earth Care Products
Horizon Bioenergy
New Biomass
Energy
Topell Energy BV
TSI
Wyssmont
Frohnleiten, AT
Paris, FR
Independence, USA
Steenwijk, NL
Quitman, USA
Duiven, NL
Seattle, USA
Fort Lee, USA
DNV GL © 2013 March 19th, 2014
Selection and risk assessment of torrefaction technology
Scoring graph
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Source: Eurosport/Reuters
DNV GL © 2013 March 19th, 2014
Next steps
Torrefaction trial with South African wood species
Storage tests
Basic and detailed engineering of a torrefaction plant
Construction (60.000 – 100.000 t/y plant)
Co-firing test + commercial co-firing
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DNV GL © 2013 March 19th, 2014
SAFER, SMARTER, GREENER
www.dnvgl.com
Thank you for your attention Please, visit us at Booth A06
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Dr Mark Beekes
Tel. +31 26 356 2705
Dr Matshela Koko
Tel. +27 11 800 6467
DNV GL © 2013 March 19th, 2014
Disclamer
This presentation or parts of it may not be copied or otherwise multiplied without
written permission of Eskom SOC Limited
All estimates and opinions included in this report constitute our judgements as of
the date of this report. However, no guarantees for correctness and/or
completeness can be given, and Eskom does not accept any liability for possible
damages resulting from usage of the data in this report.
All information in this report is intellectual property of Eskom and/ or third parties
and may only be re-published after express written permission
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