LCA of Burning Different Solid Biomass Substrates

Transcription

1 LCA of Burning Different Solid Biomass Substrates René Itten, Niels Jungbluth ESU-services Ltd., Uster, Switzerland E S U 47th LCA Discussion Symposium Berne, 23. April 2012

2 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 Page 2

3 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 Page 3

4 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 Page 4

5 System overview olive pomace Olive Pomace System Boundary Olive pomace Heat Drying Dried Olive Pomace Combustion Emissions Ash Ash disposal Emissions Page 5 Heat

6 Coffee grounds System overview pellets Coffee Grounds Poultry Litter System Boundary Heat Electricity Pellet production Pellets Poultry litter Combustion Ash Emissions Ash disposal Emissions Page 6 Heat

7 System overview dung and slurry Horse dung Horse Dung / Pig Slurry System Boundary Wood Chips Mixing with Wood Chips Dung / Slurry Mixture Pig slurry Combustion Ash Emissions Ash disposal Emissions Page 7 Heat

8 Disposal routes for the ash Ash Disposal Sanitary Landfill MSWI Landfarming 25 % 50 % 25 % Ash disposal for biomass substrates modeled like for wood according to ecoinvent Page 8

9 Flue gas treatment Cyclone Electrostatic filter Page 9

10 Combustion technology General description Device Cyclone Electrostatic filter Comment 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 wood combustion, grate furnace yes yes chips filters did not work Slurry solids and bark chips boiler furnace no no wood combustion combustion technology and flue gas treatment with improvement potentials Page 10

11 Elemental composition Elemental composition Olive pomace Coffee ground pellets Poultry litter pellets Horse dung & wood chips Pig slurry solids & bark chips Wood, 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 % % % % % % Moisture content 14.00% 14.60% 15.00% 45.00% 61.00% 14.00% Biomass substrates have a higher nitrogen, sulphur and ash content Manure mixtures are extremely wet fuels Page 11

12 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 Page 12

13 Ecological Scarcity 2006 eco-points (UBP) per MJ of heat 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) Substrates Wood Fossil Fuel Emissions Disposal ash Rest High emission during combustion lead to higher total impacts than for conventional fuels Page 13

14 Ecological Scarcity 2006 Air Emissions Particle, NO X and Benzene emissions cause more than 50% of the environmental impacts in case of the biomass substrates Page 14 Contribution relative to total Score 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) Substrates Wood Fossil Benzene Particulates NOx Methane Lead N2O Cadmium Dioxin SOx NMVOC CO2, fossil Rest

15 IPCC Global Warming Potential 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 CO 2 -eq per MJ of heat non-co2, fossil CH4, biogenic CO2 CO2, land transformation Substrates Wood Fossil Fossil fuels cause higher GWP than wood and biomass Page 15

16 Lead emissions into soil in ug per MJ of heat Page 16 Results: Soil emissions 10 Soil Emissions Heavy Metals Substrates Substrates Wood Wood Lead, Soil, agricultural Substrates Biomass substrates tend cause higher heavy metal emissions than wood but the emissions are still comparable Cadmium emissions into soil in ug per MJ of heat Wood Wood Cadmium, Soil, agricultural 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)

17 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 Page 17

18 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 Page 18

19 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 Page 19

20 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 20

21 Thanks for your attention! René Itten ESU-services GmbH, Uster, Schweiz Download the study and electronic data: Acknowledgements: The work presented here was made possible thanks to financial support from the Swiss Federal Office for Energy (FOEN). Page 21

22 Additional Slides Page 22

23 Results: Coffee grounds Direct combustion vs MSWI IPCC GWP in kg CO2-eq per kg coffee grounds Combustion in furnace Combustion in MSWI 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 Page 23

24 Results: Scenarios for Ash Disposal Ecological Scarcity Emission into air Emission into surface water Emission into ground water Emission into top soil 400 Energy resources Natural resources Deposited waste UBP per MJ of heat 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 Page 24

25 Results: Scenarios fuel preparation Ecological Scarcity 2006 and IPCC GWP UBP per MJ of heat regional storage on site regional storage on site IPCC GWP in kg CO2-eq per MJ of heat fossil, non-co2 CH4, biogenic CO2 CO2, land trans coffee ground pellets Emission into air Emission into ground water Energy resources poultry litter pellets Emission into surface water Emission into top soil Natural resources 0 regional storage on site coffee ground pellets regional storage on site poultry litter pellets Page 25

26 Substrates considered in this study (1) Olive pomace Coffee grounds Poultry Litter pellets Page 26

27 Substrates considered in this study (2) Horse dung and wood chips Slurry solids and wood chips Page 27