LCA of Burning Different Solid Biomass Substrates Itten.pdf · Fossil fuels cause higher GWP than wood and biomass 0 20 40 60 80 100 olive pomace (15 kW) coffee ground pellets (25
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LCA of Burning Different Solid Biomass Substrates
47th LCA Discussion Symposium Berne, 23. April 2012
René Itten, Niels Jungbluth
ESU-services Ltd., Uster, Switzerland
USE USE
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Introduction
• LCI’s for direct combustion of biomass substrates
• Environmental impacts of direct combustion
• Quantify emissions and impacts
• Comparison biomass substrates to wooden and
fossil fuels
• Influence of the substrates and combustion
technology
Preliminary Study
• Potential Substrates:
– About 40 substrates
– Kernels, Shells, Pomaces and other wastes
– Mainly by-products and wastes
• Selected: Olive pomace, coffee grounds, poultry
litter, horse dung and pig slurry
• Based on data availability
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Life cycle inventory analysis
• New LCI for combustion of different solid
biomass substrates
• Processes included:
– substrate preparation
– biomass combustion
– ash disposal
• Cut-Off approach for substrates
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System overview olive pomace
Drying
Combustion
Dried Olive Pomace
Heat
Ash
Ash disposal
Olive Pomace
Emissions
Emissions
Heat
System Boundary
Olive pomace
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System overview pellets
Pellet production
Combustion
Pellets
Heat
Ash
Ash disposal
Coffee GroundsPoultry Litter
Emissions
HeatElectricity
Emissions
System Boundary
Coffee grounds
Poultry litter
System overview dung and slurry
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Mixing with Wood Chips
Combustion
Dung / Slurry Mixture
Heat
Ash
Ash disposal
Horse Dung / Pig Slurry
Emissions
Emissions
Wood Chips
System Boundary
Pig slurry
Horse dung
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Disposal routes for the ash
Sanitary
Landfill MSWI
Landfarming
Ash Disposal
25 % 50 % 25 %
Ash disposal for biomass substrates modeled like for wood according to
ecoinvent
Flue gas treatment
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Cyclone Electrostatic filter
Combustion technology
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combustion technology and flue gas treatment with improvement
potentials
General description Device CycloneElectro-static filter
Comment
Olive pomace tubular reactor no no experiment in labCoffee ground pellets automatic furnace no no wood combustionPoultry litter pellets grate furnace yes no pilot plantHorse dung and wood chips
grate furnace yes yeswood combustion, filters did not work
Slurry solids and bark chips
boiler furnace no no wood combustion
Elemental c omposit ion
Olive pomaceCoffee ground
pelletsPoultry litter
pelletsHorse dung &
wood chipsPig slurry solids
& bark chipsWood, Logs
Unit kg/kg fuel, dry kg/kg fuel, dry kg/kg fuel, dry kg/kg fuel, dry kg/kg fuel, dry kg/kg fuel, dryCarbon C 47.00% 51.20% 40.00% 48.00% 46.50% 49.80%Hydrogen H 5.70% 5.50% 6.50% 5.50% 5.50% 6.00%Oxygen O 38.40% 40.40% 35.50% 37.30% 35.00% 44.00%Nitrogen N 1.10% 0.00% 3.83% 0.18% 2.20% 0.08%Sulphur S 0.10% 0.00% 0.00% 0.03% 0.43% 0.01%Ash content 7.70% 2.90% 14.20% 9.00% 10.40% 0.10%Total dry mass 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%Moisture content 14.00% 14.60% 15.00% 45.00% 61.00% 14.00%
Elemental composition
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Biomass substrates have a higher nitrogen, sulphur and ash content
Manure mixtures are extremely wet fuels
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Life cycle impact assessment • Functional unit: Provision of 1 MJ of useful heat
• Indicators: Ecological Scarcity 2006 and IPCC
GWP
• Main contributors ecological scarcity and GWP
• Heavy metal emissions into soil
0 50 100 150 200 250 300
olive pomace (15 kW)
coffee ground pellets (25 kW)
poultry litter pellets (300 kW)
horse dung and wood chips (600 kW)
slurry solids and bark chips (1000 kW)
mixed logs (6 kW)
wood pellets (15 kW)
mixed chips from forest (300 kW)
mixed chips from forest (1000 kW)
light fuel oil (100 kW)
light fuel oil (100 kW)
natural gas (>100kW)
eco-points (UBP) per MJ of heat
Fuel
Emissions
Disposal ash
Rest
Fossil
Wood
Substrates
Page 13
Ecological Scarcity 2006
High emission during combustion lead to higher total impacts than for
conventional fuels
Page 14
Ecological Scarcity 2006 Air Emissions
Particle, NOX and Benzene emissions cause more than 50% of the
environmental impacts in case of the biomass substrates
0% 20% 40% 60% 80% 100%
olive pomace (15 kW)
coffee ground pellets (25 kW)
poultry litter pellets (300 kW)
horse dung and wood chips (600 kW)
slurry solids and bark chips (1000 kW)
mixed logs (6 kW)
wood pellets (15 kW)
mixed chips from forest (300 kW)
mixed chips from forest (1000 kW)
light fuel oil (100 kW)
light fuel oil (100 kW)
natural gas (>100kW)
Contribution relative to total Score BenzeneParticulatesNOxMethaneLeadN2OCadmiumDioxinSOxNMVOCCO2, fossilRestFossil
Wood
Substrates
Page 15
IPCC Global Warming Potential
Fossil fuels cause higher GWP than wood and biomass
0 20 40 60 80 100
olive pomace (15 kW)
coffee ground pellets (25 kW)
poultry litter pellets (300 kW)
horse dung and wood chips (600 kW)
slurry solids and bark chips (1000 kW)
mixed logs (6 kW)
wood pellets (15 kW)
mixed chips from forest (300 kW)
mixed chips from forest (1000 kW)
light fuel oil (100 kW)
light fuel oil (100 kW)
natural gas (>100kW)
IPCC GWP in g CO2-eq per MJ of heat non-CO2, fossilCH4, biogenicCO2CO2, land transformation
Fossil
Wood
Substrates
Page 16
Results: Soil emissions Soil Emissions Heavy Metals
Biomass substrates tend cause higher heavy metal emissions than wood
but the emissions are still comparable
Wood Wood Substrates Substrates
0
20
40
60
80
100
120
140
160
Lead, Soil, agricultural
Lead
em
issio
ns in
to so
il in
ug
per M
J of h
eat
0
1
2
3
4
5
6
7
8
9
10
Cadmium, Soil, agricultural
Cadm
ium
em
issio
ns in
to so
il in
ug
per M
J of h
eat
olive pomace (15 kW)
coffee ground pellets (25 kW)
poultry litter pellets (300 kW)
horse dung and wood chips(600 kW)slurry solids and bark chips(1000 kW)mixed logs (6 kW)
wood pellets (15 kW)
mixed chips from forest (300kW)mixed chips from forest (1000kW)
Subs
trat
es
Woo
d
Woo
d
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Conclusions 1
• Biomass substrates cause higher impacts compared to
wooden and fossil fuels according to ecological scarcity
2006
• Biomass substrates cause lower greenhouse gas emission
compared to fossil fuels according to IPCC GWP
• Trade-off between GWP and overall environmental
impacts
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Conclusions 2
• Particulate matter emissions cause the highest share of
the impacts according to ecological scarcity
• High uncertainty because lacking data regarding particle
distribution for biomass substrates
• Some of the biomass substrates cause higher heavy metal
emissions than wooden fuels but for most of the
substrates the heavy metal emissions are equal or lower
compared to wooden fuels
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Conclusions 3 • No recommendation can be made regarding the furnace
type
• Data mainly for pilot plants without flue gas treatment
• High potential to reduce particle emissions with basic
flue gas treatment
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Conclusions
Flue gas treatment is essential to minimize particle emissions during biomass combustion.
The use of biomass substrates can reduce greenhouse gas emissions, at the cost of increased particulate matter emissions.
Page 21
Thanks for your attention!
René Itten
itten@esu-services.ch
www.esu-services.ch ESU-services GmbH, Uster, Schweiz
Acknowledgements: The work presented here was made possible thanks to financial support from the Swiss Federal Office for Energy (FOEN).
Download the study and electronic data: http://www.lc-inventories.ch/
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Additional Slides
Page 23
Results: Coffee grounds Direct combustion vs MSWI
Combustion in MSWI
Combustion in furnace
-1 -0.5 0 0.5 1
-800 -600 -400 -200 0 200 400 600 800
IPCC GWP in kg CO2-eq per kg coffee grounds
ecopoints (UBP) per kg coffee grounds
UBP'06 MAX UBP'06 MIN GWP MIN GWP MAX
Combustion of coffee grounds in MSWI causes lower impacts
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Results: Scenarios for Ash Disposal Ecological Scarcity 2006
0
50
100
150
200
250
300
350
400
450
REF LAND MSWI MSWLF REF LAND MSWI MSWLF REF LAND MSWI MSWLF REF LAND MSWI MSWLF REF LAND MSWI MSWLF
olive pomace coffee ground pellets poulry litter pellets horse dung and waste woodchips
slurry solids and bark chips
UBP
per M
J of h
eat
Emission into air Emission into surface waterEmission into ground water Emission into top soilEnergy resources Natural resourcesDeposited waste
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Results: Scenarios fuel preparation Ecological Scarcity 2006 and IPCC GWP
0
20
40
60
80
100
120
regionalstorage
on site regionalstorage
on site
coffee ground pellets poultry litter pellets
UBP
per M
J of h
eat
Emission into air Emission into surface waterEmission into ground water Emission into top soilEnergy resources Natural resources
0
0.005
0.01
0.015
0.02
0.025
0.03
regionalstorage
on site regionalstorage
on site
coffee ground pellets poultry litter pellets
IPCC
GW
P in
kg
CO2-
eq p
er M
J of h
eat
fossil, non-CO2CH4, biogenicCO2CO2, land trans
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Substrates considered in this study (1)
Olive pomace Coffee grounds Poultry Litter pellets
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Substrates considered in this study (2)
Horse dung and wood chips Slurry solids and wood chips
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