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Bradley A. Saville, Heather MacLean, Mohammad Pour Bafrani,...
Transcript of Bradley A. Saville, Heather MacLean, Mohammad Pour Bafrani,...
Bradley A. Saville, Heather MacLean, Mohammad Pour Bafrani, Tim Shen, Jon McKechnie
University of Toronto FFAB AGM May 22, 2013
Life Cycle Assessment (LCA) LCA quantifies the environmental effects of the
production of a product(s), considering the full life cycle from resource extraction through production, use of a product and disposal.
In this work, LCA is used to quantify
greenhouse gas (GHG) emissions for production of Lignocellulosic Ethanol, with different co-products and production pathways
Life Cycle Assessment Key factors:
Crop production Includes seed, fertilizer, chemicals, fuel
Harvest and extraction Includes oil/sugar extraction, transport to processing facilities
Biofuels production process Consumption/use in truck/car Co-products
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Feedstock
Plant
Distribution
Vehicle
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Energy IN
Co-Product(s)
Energy OUT
Emissions OUT
Ethanol Fuel
Amount of Biomass Used
Model Vehicle
• 2000 metric tonnes per day
• E85 (85% denatured ethanol, 15% gasoline by volume)
Fuel Produced
• Flexible fuel vehicle
• Fuel consumption • 9.48 L/100km (gasoline) • 12.65 L/100km (E85)
Life Cycle Metrics
Gaseous Emissions Energy Inputs
Waste Streams Water Consumption
• Life Cycle Metric / MJ E85 Produced
Functional Unit
Energy Common Life Cycle Metrics • Total (includes renewables)
• Fossil (includes petroleum)
• Petroleum
Emissions
• CO2, N2O, CH4 (greenhouse gases)
• All combined into CO2 equivalents using Global Warming Potentials over a 100 year timeframe
Gaseous Emissions Energy Inputs
Waste Streams Water Consumption
Characteristics • 2nd generation biofuel • Made from non-food crops • Uses a renewable feedstock • Feed can be domestically produced • Adaptable to existing
infrastructure
Sources • Agricultural residues • Wood/residues • Herbaceous crops • Portions of municipal solid waste
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Lignocellulosic Biomass
Corn (Starch based)
Petroleum Bioethanol
Many different products! Many Possibilities Few established pathways
Crude Oil
Oil Refinery
LPG
Gasoline
Naphtha Diesel Coke
Fuel Oil Paraffin
Biomass
Biorefinery
Ethanol
Biopolymers Protein
Sweeteners (Xylitol)
Lignin Pellets
Electricity
Bioethanol
Many Possibilities Few established pathways
Biomass
Biorefinery
Ethanol
Biopolymers Protein
Sweeteners (Xylitol)
Lignin Pellets
Electricity
Numerous Feedstocks
Numerous Conversion Methods
Numerous Potential Products
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Bioethanol
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Biomass
Biorefinery
Ethanol
Electricity
Single Feedstock
Single Conversion Method
Limited Set of Co-Products
Majority of Existing Studies
“Black Box Model”
Previously Studied
Detailed Modelling (Aspen Plus) of different conversion methods
Sugar
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Xylitol
Ethanol
Feedstock
Plant
Coal
Soy Protein
Grid Electricity
Lignin Pellets
Co-Product
Protein
Xylitol
Electricity
Sugar
Scenarios
Dilute Acid
Hydrolysis
Ethanol Electricity Fuel Pellets
Xylitol
Ammonia Fibre
Expansion
Auto- Hydrolysis
Fermentation
Corn Stover Switchgrass Hybrid
Poplar
Distillation Processing
Protein
Gas
olin
e
DA
EL
DA
PE
AX
EL
AX
PE
AX
PR
AH
EL
AH
PE
AH
XE
AH
XP
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
MJ o
f Ene
rgy
/ M
J of F
uel P
rodu
ced
Total Fossil Petroleum Co-Product Credit Net
At least 42% higher total energy use
Generally higher total energy use relative to gasoline pathway
Gas
olin
e
DA
EL
DA
PE
AX
EL
AX
PE
AX
PR
AH
EL
AH
PE
AH
XE
AH
XP
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
MJ o
f Ene
rgy
/ M
J of F
uel P
rodu
ced
Total Fossil Petroleum Co-Product Credit Net
At least 47% lower fossil energy use
Generally lower fossil energy use relative to gasoline pathway
Gas
olin
e
DA
EL
DA
PE
AX
EL
AX
PE
AX
PR
AH
EL
AH
PE
AH
XE
AH
XP
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
MJ o
f Ene
rgy
/ M
J of F
uel P
rodu
ced
Total Fossil Petroleum Co-Product Credit Net
Co-Product credits substantially reduce fossil energy
Co-product credit is substantial for fossil energy use
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5 G
asol
ine
Elec
Elec
/Pel
lets
Elec
Elec
/Pel
lets
Elec
Elec
/Pel
lets
Elec
/Xyl
itol
Elec
/Pel
lets
/Xyl
itol
kg C
O2e
q /
MJ E
than
ol F
uel P
rodu
ced
Fossil Energy Co-Product Credit Net
AFEX Conversion Autohydrolysis
Conversion Dilute Acid Conversion
*All non-gasoline pathways produce E85
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-0.15
-0.1
-0.05
0
0.05
0.1
0.15
Gasoline DAEL DAPE AXEL AXPE AXPR AHEL AHPE AHXE AHXP
kg C
O2e
q /
MJ E
than
ol F
uel P
rodu
ced
Co-Product Credit Downstream Upstream Net
At least 60% reduction relative to gasoline
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
Gasoline DAEL DAPE AXEL AXPE AXPR AHEL AHPE AHXE AHXP
kg C
O2e
q /
MJ E
than
ol F
uel P
rodu
ced
Co-Product Credit Downstream Upstream Net
Pathway with largest net GHG emissions reduction is the autohydrolysis conversion pathway co-producing xylitol and lignin pellets
140% net GHG reduction relative to gasoline
Summary: Impact of Co-products
Co-products can have a significant effect on LCA metrics Large credit if the co-product displaces a GHG-intensive
existing product e.g., renewable electricity displaces coal-derived electricity
Small credit if existing product has low GHG intensity Key Metrics for co-products:
High margin Low energy to produce Displaces energy and GHG-intensive product
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