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

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