lca of burning different solid biomass...
TRANSCRIPT
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 Grounds
Poultry Litter
Emissions
Heat
Electricity
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 filterComment
Olive pomace tubular reactor no no experiment in lab
Coffee ground pellets automatic furnace no no wood combustion
Poultry litter pellets grate furnace yes no pilot plant
Horse dung and wood
chipsgrate furnace yes yes
wood combustion,
filters did not work
Slurry solids and bark
chipsboiler furnace no no wood combustion
Elemental
compositionOlive pomace
Coffee ground
pellets
Poultry litter
pellets
Horse dung &
wood chips
Pig 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, dry
Carbon 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
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Ecological Scarcity 2006
High emission during combustion lead to higher total impacts than for
conventional fuels
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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 Benzene
Particulates
NOx
Methane
Lead
N2O
Cadmium
Dioxin
SOx
NMVOC
CO2, fossil
RestFossil
Wood
Substrates
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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, fossil
CH4, biogenic
CO2
CO2, land transformation
Fossil
Wood
Substrates
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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
issi
on
s in
to s
oil
in u
g p
er M
J o
f h
eat
0
1
2
3
4
5
6
7
8
9
10
Cadmium, Soil, agricultural
Cad
miu
m e
mis
sio
ns
into
so
il in
ug
per
MJ
of
hea
t
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)
Sub
stra
tes
Wo
od
Wo
od
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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
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 wood
chips
slurry solids and bark chips
UB
P p
er
MJ
of
he
at
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
UB
P pe
r M
J of
hea
t
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
IPC
C G
WP
in
kg
CO
2-e
q p
er
MJ
of
he
at
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