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Biomass Combustion in Europe
Thomas Nussbaumer
Lucerne University of Applied Sciences 6048 Horw Verenum RampD in Bioenergy 8006 Zurich
SWITZERLAND
Verenum EMEP Albany (NY) USA 111607
Biomass Combustion in Europe
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
The fossil Period A Peak in History
Verenum
1 Heat 2 Power 3 Transport
Verenum
Carbon C cle for Bioener
y gy
Verenum
CO2
Ca K
C Ca K N
CO + Corg + Cel
NOx+N2
hν
KCl CaCO3
Sustainability Requirements for Bioenergy
1 Sustainable biomass productionNo deforestation
2 Social aspectsBiomass for food first no competition
3 Ecological aspectsAcceptable air pollution
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Flame Principles
Verenum Kerze mit und ohne Russ GasfeuerzeugKerze in Glas Wandtafel mit Molekuumllen Neue Stoffe entstehen Beweis Kerze mit schwarzem Russ
Diffusion Flame
Premixed Flame
Wood Combustion with Air
λ = Excess air ratio = AirAirstoch = O2 O2 min
CH14O07 + λ (O2 + 376 N2)
ndashgt Intermediate Products (CO H2 CmHn)
CO2 + 07 H2O + (λndash1) O2 + λ 376 N2
+ 183 MJkg
Verenum
100000100001000100101
10
100
1000
10000
HC
CO
[mgm3]
[mgm3]
HC und CO in [mgm3] bei 11 Vol O2
a
b
c
Correlation between CO and Hydrocarbon (HC)
Open Chimney
Log Wood Boiler
Automatic Wood ChipBoiler (under stoker)
[Nussbaumer 1989] Verenum
mb chamberat extraction
gt 05 s
Requirements for Complete Burnout T T T
Temperature ndash Time ndash Turbulence (Mixing)
gt 850degC
-co (dry wood ) -he λ lt 2
2-stage Comb with primary amp secondary Air Ventilator Mixing zone
Re gt 2300
Verenum
T (λ)
Influence of excess air on Temperature
Excess air ratio
T (λ)
dry wood
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Biomass Combustion in Europe
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
The fossil Period A Peak in History
Verenum
1 Heat 2 Power 3 Transport
Verenum
Carbon C cle for Bioener
y gy
Verenum
CO2
Ca K
C Ca K N
CO + Corg + Cel
NOx+N2
hν
KCl CaCO3
Sustainability Requirements for Bioenergy
1 Sustainable biomass productionNo deforestation
2 Social aspectsBiomass for food first no competition
3 Ecological aspectsAcceptable air pollution
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Flame Principles
Verenum Kerze mit und ohne Russ GasfeuerzeugKerze in Glas Wandtafel mit Molekuumllen Neue Stoffe entstehen Beweis Kerze mit schwarzem Russ
Diffusion Flame
Premixed Flame
Wood Combustion with Air
λ = Excess air ratio = AirAirstoch = O2 O2 min
CH14O07 + λ (O2 + 376 N2)
ndashgt Intermediate Products (CO H2 CmHn)
CO2 + 07 H2O + (λndash1) O2 + λ 376 N2
+ 183 MJkg
Verenum
100000100001000100101
10
100
1000
10000
HC
CO
[mgm3]
[mgm3]
HC und CO in [mgm3] bei 11 Vol O2
a
b
c
Correlation between CO and Hydrocarbon (HC)
Open Chimney
Log Wood Boiler
Automatic Wood ChipBoiler (under stoker)
[Nussbaumer 1989] Verenum
mb chamberat extraction
gt 05 s
Requirements for Complete Burnout T T T
Temperature ndash Time ndash Turbulence (Mixing)
gt 850degC
-co (dry wood ) -he λ lt 2
2-stage Comb with primary amp secondary Air Ventilator Mixing zone
Re gt 2300
Verenum
T (λ)
Influence of excess air on Temperature
Excess air ratio
T (λ)
dry wood
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
The fossil Period A Peak in History
Verenum
1 Heat 2 Power 3 Transport
Verenum
Carbon C cle for Bioener
y gy
Verenum
CO2
Ca K
C Ca K N
CO + Corg + Cel
NOx+N2
hν
KCl CaCO3
Sustainability Requirements for Bioenergy
1 Sustainable biomass productionNo deforestation
2 Social aspectsBiomass for food first no competition
3 Ecological aspectsAcceptable air pollution
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Flame Principles
Verenum Kerze mit und ohne Russ GasfeuerzeugKerze in Glas Wandtafel mit Molekuumllen Neue Stoffe entstehen Beweis Kerze mit schwarzem Russ
Diffusion Flame
Premixed Flame
Wood Combustion with Air
λ = Excess air ratio = AirAirstoch = O2 O2 min
CH14O07 + λ (O2 + 376 N2)
ndashgt Intermediate Products (CO H2 CmHn)
CO2 + 07 H2O + (λndash1) O2 + λ 376 N2
+ 183 MJkg
Verenum
100000100001000100101
10
100
1000
10000
HC
CO
[mgm3]
[mgm3]
HC und CO in [mgm3] bei 11 Vol O2
a
b
c
Correlation between CO and Hydrocarbon (HC)
Open Chimney
Log Wood Boiler
Automatic Wood ChipBoiler (under stoker)
[Nussbaumer 1989] Verenum
mb chamberat extraction
gt 05 s
Requirements for Complete Burnout T T T
Temperature ndash Time ndash Turbulence (Mixing)
gt 850degC
-co (dry wood ) -he λ lt 2
2-stage Comb with primary amp secondary Air Ventilator Mixing zone
Re gt 2300
Verenum
T (λ)
Influence of excess air on Temperature
Excess air ratio
T (λ)
dry wood
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
1 Heat 2 Power 3 Transport
Verenum
Carbon C cle for Bioener
y gy
Verenum
CO2
Ca K
C Ca K N
CO + Corg + Cel
NOx+N2
hν
KCl CaCO3
Sustainability Requirements for Bioenergy
1 Sustainable biomass productionNo deforestation
2 Social aspectsBiomass for food first no competition
3 Ecological aspectsAcceptable air pollution
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Flame Principles
Verenum Kerze mit und ohne Russ GasfeuerzeugKerze in Glas Wandtafel mit Molekuumllen Neue Stoffe entstehen Beweis Kerze mit schwarzem Russ
Diffusion Flame
Premixed Flame
Wood Combustion with Air
λ = Excess air ratio = AirAirstoch = O2 O2 min
CH14O07 + λ (O2 + 376 N2)
ndashgt Intermediate Products (CO H2 CmHn)
CO2 + 07 H2O + (λndash1) O2 + λ 376 N2
+ 183 MJkg
Verenum
100000100001000100101
10
100
1000
10000
HC
CO
[mgm3]
[mgm3]
HC und CO in [mgm3] bei 11 Vol O2
a
b
c
Correlation between CO and Hydrocarbon (HC)
Open Chimney
Log Wood Boiler
Automatic Wood ChipBoiler (under stoker)
[Nussbaumer 1989] Verenum
mb chamberat extraction
gt 05 s
Requirements for Complete Burnout T T T
Temperature ndash Time ndash Turbulence (Mixing)
gt 850degC
-co (dry wood ) -he λ lt 2
2-stage Comb with primary amp secondary Air Ventilator Mixing zone
Re gt 2300
Verenum
T (λ)
Influence of excess air on Temperature
Excess air ratio
T (λ)
dry wood
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Carbon C cle for Bioener
y gy
Verenum
CO2
Ca K
C Ca K N
CO + Corg + Cel
NOx+N2
hν
KCl CaCO3
Sustainability Requirements for Bioenergy
1 Sustainable biomass productionNo deforestation
2 Social aspectsBiomass for food first no competition
3 Ecological aspectsAcceptable air pollution
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Flame Principles
Verenum Kerze mit und ohne Russ GasfeuerzeugKerze in Glas Wandtafel mit Molekuumllen Neue Stoffe entstehen Beweis Kerze mit schwarzem Russ
Diffusion Flame
Premixed Flame
Wood Combustion with Air
λ = Excess air ratio = AirAirstoch = O2 O2 min
CH14O07 + λ (O2 + 376 N2)
ndashgt Intermediate Products (CO H2 CmHn)
CO2 + 07 H2O + (λndash1) O2 + λ 376 N2
+ 183 MJkg
Verenum
100000100001000100101
10
100
1000
10000
HC
CO
[mgm3]
[mgm3]
HC und CO in [mgm3] bei 11 Vol O2
a
b
c
Correlation between CO and Hydrocarbon (HC)
Open Chimney
Log Wood Boiler
Automatic Wood ChipBoiler (under stoker)
[Nussbaumer 1989] Verenum
mb chamberat extraction
gt 05 s
Requirements for Complete Burnout T T T
Temperature ndash Time ndash Turbulence (Mixing)
gt 850degC
-co (dry wood ) -he λ lt 2
2-stage Comb with primary amp secondary Air Ventilator Mixing zone
Re gt 2300
Verenum
T (λ)
Influence of excess air on Temperature
Excess air ratio
T (λ)
dry wood
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Sustainability Requirements for Bioenergy
1 Sustainable biomass productionNo deforestation
2 Social aspectsBiomass for food first no competition
3 Ecological aspectsAcceptable air pollution
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Flame Principles
Verenum Kerze mit und ohne Russ GasfeuerzeugKerze in Glas Wandtafel mit Molekuumllen Neue Stoffe entstehen Beweis Kerze mit schwarzem Russ
Diffusion Flame
Premixed Flame
Wood Combustion with Air
λ = Excess air ratio = AirAirstoch = O2 O2 min
CH14O07 + λ (O2 + 376 N2)
ndashgt Intermediate Products (CO H2 CmHn)
CO2 + 07 H2O + (λndash1) O2 + λ 376 N2
+ 183 MJkg
Verenum
100000100001000100101
10
100
1000
10000
HC
CO
[mgm3]
[mgm3]
HC und CO in [mgm3] bei 11 Vol O2
a
b
c
Correlation between CO and Hydrocarbon (HC)
Open Chimney
Log Wood Boiler
Automatic Wood ChipBoiler (under stoker)
[Nussbaumer 1989] Verenum
mb chamberat extraction
gt 05 s
Requirements for Complete Burnout T T T
Temperature ndash Time ndash Turbulence (Mixing)
gt 850degC
-co (dry wood ) -he λ lt 2
2-stage Comb with primary amp secondary Air Ventilator Mixing zone
Re gt 2300
Verenum
T (λ)
Influence of excess air on Temperature
Excess air ratio
T (λ)
dry wood
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Flame Principles
Verenum Kerze mit und ohne Russ GasfeuerzeugKerze in Glas Wandtafel mit Molekuumllen Neue Stoffe entstehen Beweis Kerze mit schwarzem Russ
Diffusion Flame
Premixed Flame
Wood Combustion with Air
λ = Excess air ratio = AirAirstoch = O2 O2 min
CH14O07 + λ (O2 + 376 N2)
ndashgt Intermediate Products (CO H2 CmHn)
CO2 + 07 H2O + (λndash1) O2 + λ 376 N2
+ 183 MJkg
Verenum
100000100001000100101
10
100
1000
10000
HC
CO
[mgm3]
[mgm3]
HC und CO in [mgm3] bei 11 Vol O2
a
b
c
Correlation between CO and Hydrocarbon (HC)
Open Chimney
Log Wood Boiler
Automatic Wood ChipBoiler (under stoker)
[Nussbaumer 1989] Verenum
mb chamberat extraction
gt 05 s
Requirements for Complete Burnout T T T
Temperature ndash Time ndash Turbulence (Mixing)
gt 850degC
-co (dry wood ) -he λ lt 2
2-stage Comb with primary amp secondary Air Ventilator Mixing zone
Re gt 2300
Verenum
T (λ)
Influence of excess air on Temperature
Excess air ratio
T (λ)
dry wood
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Flame Principles
Verenum Kerze mit und ohne Russ GasfeuerzeugKerze in Glas Wandtafel mit Molekuumllen Neue Stoffe entstehen Beweis Kerze mit schwarzem Russ
Diffusion Flame
Premixed Flame
Wood Combustion with Air
λ = Excess air ratio = AirAirstoch = O2 O2 min
CH14O07 + λ (O2 + 376 N2)
ndashgt Intermediate Products (CO H2 CmHn)
CO2 + 07 H2O + (λndash1) O2 + λ 376 N2
+ 183 MJkg
Verenum
100000100001000100101
10
100
1000
10000
HC
CO
[mgm3]
[mgm3]
HC und CO in [mgm3] bei 11 Vol O2
a
b
c
Correlation between CO and Hydrocarbon (HC)
Open Chimney
Log Wood Boiler
Automatic Wood ChipBoiler (under stoker)
[Nussbaumer 1989] Verenum
mb chamberat extraction
gt 05 s
Requirements for Complete Burnout T T T
Temperature ndash Time ndash Turbulence (Mixing)
gt 850degC
-co (dry wood ) -he λ lt 2
2-stage Comb with primary amp secondary Air Ventilator Mixing zone
Re gt 2300
Verenum
T (λ)
Influence of excess air on Temperature
Excess air ratio
T (λ)
dry wood
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Wood Combustion with Air
λ = Excess air ratio = AirAirstoch = O2 O2 min
CH14O07 + λ (O2 + 376 N2)
ndashgt Intermediate Products (CO H2 CmHn)
CO2 + 07 H2O + (λndash1) O2 + λ 376 N2
+ 183 MJkg
Verenum
100000100001000100101
10
100
1000
10000
HC
CO
[mgm3]
[mgm3]
HC und CO in [mgm3] bei 11 Vol O2
a
b
c
Correlation between CO and Hydrocarbon (HC)
Open Chimney
Log Wood Boiler
Automatic Wood ChipBoiler (under stoker)
[Nussbaumer 1989] Verenum
mb chamberat extraction
gt 05 s
Requirements for Complete Burnout T T T
Temperature ndash Time ndash Turbulence (Mixing)
gt 850degC
-co (dry wood ) -he λ lt 2
2-stage Comb with primary amp secondary Air Ventilator Mixing zone
Re gt 2300
Verenum
T (λ)
Influence of excess air on Temperature
Excess air ratio
T (λ)
dry wood
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
100000100001000100101
10
100
1000
10000
HC
CO
[mgm3]
[mgm3]
HC und CO in [mgm3] bei 11 Vol O2
a
b
c
Correlation between CO and Hydrocarbon (HC)
Open Chimney
Log Wood Boiler
Automatic Wood ChipBoiler (under stoker)
[Nussbaumer 1989] Verenum
mb chamberat extraction
gt 05 s
Requirements for Complete Burnout T T T
Temperature ndash Time ndash Turbulence (Mixing)
gt 850degC
-co (dry wood ) -he λ lt 2
2-stage Comb with primary amp secondary Air Ventilator Mixing zone
Re gt 2300
Verenum
T (λ)
Influence of excess air on Temperature
Excess air ratio
T (λ)
dry wood
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
mb chamberat extraction
gt 05 s
Requirements for Complete Burnout T T T
Temperature ndash Time ndash Turbulence (Mixing)
gt 850degC
-co (dry wood ) -he λ lt 2
2-stage Comb with primary amp secondary Air Ventilator Mixing zone
Re gt 2300
Verenum
T (λ)
Influence of excess air on Temperature
Excess air ratio
T (λ)
dry wood
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
T (λ)
Influence of excess air on Temperature
Excess air ratio
T (λ)
dry wood
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Group of Pollutants from Wood Combustion
CH14O07 + O2 rarr CO2 + 07 H2O
N
K Ca Na Cl
1
2
3
rarr CO CXHY Corg soot
rarr NOX
Srarr KCl K2SO4 CaCO3
PM
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Biomass Combustion in Euro e
Verenum
p
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
1-stage combustion
Air C H O
+ Air O2 + N2
at λ gt 1
CO2 H2O O2 N2
CO CxHy
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
CO (λ) Influence of Excess Air Lambda on CO
Verenum
1-stage combustion
Eta (λ)
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Limitations of 1-stage Combustion
Problem 3 Air Leakage
Problem 6 Flame
Quenching
Problem 5 Heat Extraction in Combustion
Zone
Problem 4 Gas Leakage
Problem 2 Mixing Air + Gas
Problem 1 Air Distribution
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
1-stage Combustion Wood Stove
Verenum Eta lt 60
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Verenum
Organic PM Tar Soot
[Kaumlgi amp Schmatloch 2002]
Heuberger in [Klippel amp Nussbaumer 2007]
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
1-stage Combustion with Combustion Chamber
Air
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Verenum
HovalHoval
2-stage Combustion with forced Downdraft Wood C H O
CO H2 CxHyCO2 N2
+ Air λ gt 1 O2 + N2
CO2 H2O N2
+ Air λ lt 1 O2 + N2
Eta gt 90 ndash Heat Storage
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
2-stage Combustion with forced Downdraft
Verenum
Premixed flame
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
2-stage Combustion with Downdraft and Grate
Schmid
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Combustion control
CO (λ) Influence of Excess Air Lambda on CO
Verenum
Simple wood stove
Furnace with 2-stage combustion
Autom furnace 2000 Pellet furnace
Autom furnace 1990
Downdraft boilers are sensitive for channelling and bridging ndashgt not suited for fine wood (dust) or very large logs
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Verenum
Detail of stove 3
Tiba (Switzerland)
Prototype 2-stage Stove
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Verenum
2-stage Combustion Stove in Operation
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Pellet Boiler with Automatic Ignition
Verenum Hargassner (Austria) Eta gt 90
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Pellet Boiler with Grate for periodic Ash Removal
Verenum Liebi LNC AG (Switzerland)
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Under Stoker Boiler Grate Boiler
Verenum
w asymp 10 ndash 50 a lt 5 w asymp 10 ndash 55 a lt 50
200 kW 2 MW 400 kW gt10 MW
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Under Stoker Boiler
200 kW 2 MW
Grate Boiler w asymp 10 ndash 55 a lt 50
400 kW gt10 MW Schmid (Switzerland)
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
District Heating 64 MW
Schmid AG Wilderswil Interlaken (Victoria-Jungfrau)
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
NO+NH2rarrN2+H2O
T T T Time Temp Turbulence
bull Mixing limits burnoutbull Excess air low (15) and
accurately controlled
Burnout quality
[Bruch amp Nussbaumer 1998] Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Verenum
Combustion Modeling
Verenum
[Bruch amp Nussbaumer 1998]
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Fluid Dynamics Model Laser Camera
Verenum [Brzovic Nussbaumer amp Baillifard 2007]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Particle Measurement
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Ver leich der Toxizitaumlt verschiedener Partikel
Verenum
6
7
8
4
3
1
8
5
2
g Wood stove with bad operation
Wood soot and tar ( condens)
Toxicity = 10
Diesel soot Diesel car without particle filter
Automatic wood furnace Ash particles = salts
Toxicity = 1
Toxicity lt 02
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
Inorganic particles (AWC)
Similar for empty filter
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Results of Cytotoxicity Tests
Verenum
Cell Survival
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Particle concentration in cell medium [gml]
Su
rviv
al
[]
Diesel soot
particles from bad combustion conditions in a small wood stove
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Origin and detection of PM from biomass combustion
Salts
Soot
Tar
Origin
solid
Form
+
Filter at 180degC (VDI)
(+)
Impingerafter filter
(EPA)
Ash
Incom-plete com-
bustion liquid ndash +
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Salts 100 lt 20
Soot lt 5 lt 20 100 5 000
Tar lt 5 lt 5 400 10 000
Total PM Verenum
lt 100 lt 50 500 15 000
Typicallyoperated
wood stove
Ideallyoperated
wood stove
Badlyoperated
wood stove
Automaticwood
combustion
Typical Emissions (mgm3 13 Vol- O2 )
mgMJ = 068 x mgm3
13 Vol- O2
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
ndash +
Clean gas
+
Raw gas Condensation C-content lt 2
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
ndash +
+
Scheuch
Particle precipitation
Pre dedusting gt 5 microm Fine particle removal lt 10 lt 001 microm Cyclone Electrostatic Precipitator (ESP) Fabric filter (FF)
Aerob-Beth
Raw gas Clean gas
Scheuch
Condensation C-content lt 2
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Conversion of Fuel-Nitrogen
N in Fuel -NH2
NO O2
N2O2
HCN NH3
Temp
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
λ = 07
NO+NH2 rarrN2+H2O
[Keller amp Nussbaumer 1994] 2001] [Salzmann amp NussbaumerVerenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Air staging
Verenum
Muumlller
Vyncke
Air staging and Fuel staging
Reduction zone
[Salzmann amp Nussbaumer 2001]
[Fastenaekels amp Nussbaumer 2002]
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Biomass Combustion in Europe
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
PCDDF as a function of carbon burnout
[Oehme et al 1987] Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Biomass Combustion in Euro e
p
Verenum
1 Introduction 2 Fundamentals 3 One-stage combustion 4 Two-stage combustion for high burnout
a) Log wood b) Pellets c) Automatic Boilers 5 Particle emissions 6 NOX emissions 7 Other pollutants 8 Conclusions
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Conclusions (12) 1 Biomass combustion exhibits a relevant potential 2 Efficiencies of gt 80 are achievable in small and
medium scale 3 Wood combustion can cause PM PAH CO VOC 4 Wood combustion is a major source of organic PM today
5 PM consists of salts (s) soot (s) amp organic condensables
6 Salts from automatic plants are less toxic than soot and can be reduced by secondary measures
7 Soot and organic condensables are highly toxic and need to be reduced from manual combustion
8 Two-stage combustion at optimum excess air ratio thanks to ideal operation andor advanced combustioncontrol enables high combustion quality
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Conclusions (22) 1 Wood stoves and old or simple wood boilers often
ndash exhibit no real two-stage combustion ndash exhibit too small combustion chamber if filled ndash miss heat storage ndash are not capable to be operated at part load after filling ndash can be operated with lack of oxygen
2 An environmentally friendly use of wood in residential applications is a huge challenge and needs improvement in technology application and regulation
3 All other fuels than natural wood (agricultural biomass waste) can lead to significantly higher air pollution ie PM NOX HCl PCDDF heavy metals) and need to be restricted to large plants with flue gas cleaning
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
Acknowled ments
g
AcknowledgmentsSwiss Federal Office for Energy Swiss Agency of the Environment
Thomas Nussbaumer Switzerland
ndash University of Applied Sciences Lucerne ndash Verenum Zurich
wwwverenumch
Verenum
top related