Biomass and Coal Chars, and their Blends · Char Preparation • Samples prepared from Australian...
Transcript of Biomass and Coal Chars, and their Blends · Char Preparation • Samples prepared from Australian...
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Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Biomass and Coal Chars,Biomass and Coal Chars,Biomass and Coal Chars,Biomass and Coal Chars,Biomass and Coal Chars,Biomass and Coal Chars,Biomass and Coal Chars,Biomass and Coal Chars,
and their Blends and their Blends and their Blends and their Blends and their Blends and their Blends and their Blends and their Blends
Naoko Ellis Naoko Ellis Naoko Ellis Naoko Ellis and Mohammad Masnadi
Chemical and Biological Engineering
Clean Energy Research Centre
University of British Columbia
Canada
David J. Harris and Daniel G. Roberts
CSIRO Energy Technology
Kenmore, QLD
Australia
ContentContent• Canadian perspective
• Motivation
• Co-gasification
• Australian coal and Canadian biomass
• Experimental
• Char generation and characterization
• Fixed bed char reactivity study
• Future work
• Gasification research at UBC
• Invitation to Vancouver
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Canada’s Energy SystemCanada’s Energy System
3333Source: http://dev3.centreforenergy.com/FactsStats/MapsCanada/CA-EnergyMap.asp
Canadian CoalCanadian Coal
• Production: 65-75 Mt annually
• >40% exported
• Consumed 58 million tonnes of coal in 2006
• Most used to generate electricity• 74 % in Alberta, 63 % in Saskatchewan, 60 % in Nova Scotia,
and 18 % in Ontario from coal
• Clean coal technology: CO2 capture4444Source: http://www.nrcan.gc.ca/energy/sources/1205
Canada’s Energy MixCanada’s Energy Mix
5555http://www.neb-one.gc.ca/clf-nsi/rnrgynfmtn/nrgyrprt/nrgyftr/2011/fctsht1134mrgngfl-eng.html
Motivation Motivation Co-gasification of coal and biomass
• Coal:
• High energy density
• Conventional technology
• Supply network
• Biomass:
• Renewable
• Logistics and infrastructure issue
• Reactive
• High tar content
• Additionally:
• Catalytic/synergistic effect on gasification
• Lower tar content
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flux
O2
CO/CO2
slag
CO2 and H2O
CO + H2
Coal Conversion in GasificationCoal Conversion in Gasification• Coal gasification is a multi-stage process
• Coal pyrolysis
• Rapid volatile release
• Determines char yield and morphology
• Combustion
• Limited, fast. O2 consumed early in process
• Exothermic, provides heat for endothermic gasification reactions
• Char Gasification
• Slow, rate determining. Endothermic
• CO2 and H2O converted to CO and H2.
• Slag formation and flow
• Flux may be required to achieve adequate viscosity
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FeedstockFeedstock
Coal (CRC272)Coal (CRC272)Coal (CRC272)Coal (CRC272) BC PineBC PineBC PineBC Pine
Proximate (%, db)Proximate (%, db)Proximate (%, db)Proximate (%, db)
air dried moisture 2.3 7.0
ash 10.1 1.0
volatile matter 35.0 78.0
fixed carbon 52.6 14.0
Ultimate Ultimate Ultimate Ultimate (% (% (% (% dafdafdafdaf))))
Cabon 82.6 51.7
Hydrogen 5.36 5.97
Nitrogen 1.68 0.18
Sulfur 1.04 0.04
Oxygen (diff) 9.4 42.2
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Char PreparationChar Preparation• Samples prepared from Australian coal and Canadian pine
• Tube furnace at 900°C
• Sized samples (-1.0 +0.6 mm) of coal, biomass and blends are placed in a tube furnace under slow pyrolysis conditions
• Heating rate of 20°C/min under Nitrogen for 2 hrs holding time
• Resulting char is crushed and sieved to -1.0 +0.6 mm size range
• Char yield based on as received weight ratio
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Moisture Volatiles
Biomass 7.2% 71.4%
Coal 1.8% 33.5%
0.0 0.2 0.4 0.6 0.8 1.0
20
30
40
50
60
70
Ch
ar
Yie
ld, w
t%
Biomass wt ratio, -
Char Surface AreaChar Surface Area
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0.0 0.2 0.4 0.6 0.8 1.0
200
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400
500
600
0
20
40
60
80
100
Surf
ace A
rea
DR m
2/g
Biomass wt. ratio, -
Surface area DR
m2/g
BET m2/g
BE
T m
2/g
Char Surface AreaChar Surface Area
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0.0 0.2 0.4 0.6 0.8 1.0
200
300
400
500
600
0
20
40
60
80
100
Su
rfa
ce A
rea
DR m
2/g
Biomass char wt. ratio, -
Surface area DR
m2/g
BET m2/g
BE
T m
2/g
Char ReactivityChar ReactivityCO2 gasification mechanism
Steam gasification mechanism
12121212Hodge, 2009
Cf + H2O C(O) + H2
C(O) → CO + Cf′
Cf + H2 → C(H2)
Cf + CO2 C(O) + CO
C(O) → CO + Cf′
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COCO22 GasificationGasification
Specific reaction rate at 900ºC
Surface Area EvolutionSurface Area Evolution• CO2 gasification at 10% Conversion
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0.0 0.2 0.4 0.6 0.8 1.0
200
300
400
500
600
700
Initial SA
SA after 10% Conversion
Su
rface
Are
aD
R m
2/g
Biomass wt. ratio left in char, -0.0 0.2 0.4 0.6 0.8 1.0
0
100
200
300
400
500 Initial BET
BET after 10% Conversion
BE
T,
m2/g
Biomass wt. ratio left in char, -
Char ReactivityChar Reactivity
Surface related intrinsic reaction rate
0.0 0.2 0.4 0.6 0.8 1.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Initial rate/initial SA
after 10% conversion
Rea
ctio
n r
ate
ba
se
d o
n s
urf
ace a
rea
Biomass char wt. ratio, -
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Activation EnergyActivation Energy• CO2 gasification at 10% Conversion
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0.0 0.2 0.4 0.6 0.8 1.0
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220
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300
Activa
tio
n E
nerg
y, kJ/m
ol
biomass char wt. ratio, -
-1.0 +0.6 mm
-1.0 mm
-0.6 +0.425 mm
Hodge et al. (2010)
Hodge et al., Energy Fuels, 24, 100-107 (2010)
Steam GasificationSteam Gasification
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• Specific reaction rate at 900ºC
Intrinsic Rates and SAIntrinsic Rates and SA• Steam gasification reactivity
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0% 0.1% 0.248% 0.498% 1.0%
0
100
200
300
400
500
600
SA
DR, m
2 /g
wt. % biomass char
initial
after steam gasification
0.0 0.2 0.4 0.6 0.8 1.0
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Rea
ctio
n r
ate
base
d o
n s
urf
ace a
rea
Biomass char wt. ratio, -
Initial rate/initial SA
after 10% conversion
Future WorkFuture Work• Ash analysis (low temp analysis)
• Char morphology
• Catalytic effects
• Secondary Ion Mass Spectrometry
• intensity of K+
• Crystalinity
19191919
(a)
(b)
(c)
(a) Coal (b) Fluid coke (c) Switchgrass
University of British ColumbiaUniversity of British Columbia
BC Carbon Tax BC Carbon Tax –– since 2008since 2008
First tax of its kind in North America
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UBC's Vancouver campus:
total GHG emissions (2008) 60,400 CO2-e tonnes
Business as usual approach:
An estimated $50 million in carbon tax and carbon offsets over the next 25 year period
Reducing our GHG emissions will reduce the carbon liability to $33 million.
2 MW Demonstration Layout2 MW Demonstration Layout
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UBC System Summary
Required fuel: 12,000 BDMT/year (2/3 trucks/day)
Net Power: 1.7MWe
Net Thermal:10 MMBtu/hr (80,000 MMBtu/yr)
(~8% of based steam load and ~4% of peak electricity demand)
CO2 Reduction: 5,000 tpy
NexterraNexterra SystemSystem
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Campus as a Living Lab concept
UBC Clean Energy Research CentreUBC Clean Energy Research Centre
• Biomass feedstock and logistics
• Biomass pre-treatment
• Torrefaction and pelletization
• Integrated gasification and looping CO2 capture
• CO2 capture sorbent reactivity (pressure and temp swing)
• CO2 capture sorbent attrition
• Biomass tar cracking unit
• Dual fluidized bed gasifier
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Gasifier Combustor Combustor
Gasi
fier
Gasifier
Com
bust
or
Steam Air Steam Air Steam Air
Syngas Flue gas Syngas
Flue gas Syngas
Flue gas
Biomass Biomass Biomass
(I) (II) (III)
Integrated Fluidization Bed Gasification Integrated Fluidization Bed Gasification with Looping COwith Looping CO22 CaptureCapture
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Gasifier Calciner
Fuel
Sorbent with
CO2
Sorbent
Concentrated
CO2
H2O
Syngas
Overall Goal:To test the most promising material in the UBC pilot plant: gasification and capture
Sorbents being synthesized, prepared,
pelletized, coated and/or tested:
•Calcite
•Limestone•lithium zirconate
•lithium orthosilicate•sodium silicate
Carbon Management CanadaCarbon Management CanadaCarbon Management CanadaCarbon Management Canada
AcknowledgementAcknowledgement
• Natural Sciences and Engineering Research Council of Canada
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A special issue of ‘Fuel’ will feature the most worthy papers from iSGA-3
For more information go to: www.isga3.com
Building on successful iSGA conferences in China (2008) and Japan (2010).
iSGA-3 will cover the science, technology and policy of gasification of coal,
biomass and other carbonaceous feedstocks, as well as applications to power generation, production of liquid fuels, and related topics.
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