inflence of ignition on particle emission from residential wood combustion

8/14/2019 inflence of ignition on particle emission from residential wood combustion

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Influence of Ignition and OperationType on Particle Emissions fromResidential Wood Combustion

Anna Doberer1Jrgen Good1,2

Thomas Nussbaumer1,2

1Lucerne University of Applied Sciences, Horw2Verenum Research, Zurich

SWITZERLAND

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1. Introduction2. Objectives

3. Method

4. Results

5. Conclusions


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Measurements in Switzerland

demonstrate, that about 80% of

soot in an alpine valley near thehighway originates from wood

combustion [Prvot et al., 2006].

Background

By using emission factors from type-test measurements,

PM10 in the ambient air is strongly under-estimated.

Earlier investigations reveal that condensables can

contribute significantly to total PM emission

[Klippel & Nussbaumer, 2007].

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3. Method

4. Results

5. Conclusions


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Objectives

1. Influence of operation

2. Differences between type-test and real-lifeconditions on PM emissions

3. To assess not only solid particles, but also

condensables and VOC since they may form SOA

4. Recommendations for optimum operation in practice

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3. Methods

4. Results

5. Conclusions


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LaboratoryPracticeWood combustiondevices

XXWood stoves

-XTile stove

-XChimney

ongoingXLog wood boiler

X-Pellet stove

ongoing-Pellet boiler

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Sampling and Measurement of PM

Gravimetric determination of PMaccording to VDI 2066

- Isokinetic sampling

- Filter temperature of 160C

Sampling of condensables according toEPA method 5H

- Based on water filled impingers

- Sampling at temperatures close to 0C

Sampling during start-up, stable operation and burnout


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Ignition mode

- from the bottom

- from the top

Operating conditions

- excess air

- batch and log size

- fuel moisture

- flue draft

Investigated Parameters

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0

5

10

15

00:00 01:00 02:00 03:00 04:00 05:00 06:00

[P

a]

Kaminzug

Type-test conditions versus natural draft

0

50

100

150

200

250

300

00:00 01:00 02:00 03:00 04:00 05:00 06:00

[C]

Abgastemperatur

Simulation of natural draft:

p(T) = 0.0671 T 0.287

R2 > 0.99

chimney draft

stack gas temperature

Natural draft in practiceis not constant, but showsa strong correlation withthe stack gas temperature

12 Pa


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1. Introduction

2. Objectives

3. Method

4. Results

5. Conclusions

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Emission during start-up, stable operation and burnout

excess air

PM[mg/m

n

3]

PM [%]

50%

20 minKlippel and Nussbaumer, 2006


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486

299

219

83

212

122

478

79

0

100

200

300

400

500

600

heavy wood stove tile stove stove without heat

storage

chimney

PM[

mg/mN

3]duringstart-up

ignition from the bottom ignition from the top

Ignition from the bottom versus from the top

*Vock and Jenni, 2007

* *

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Flyer


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Influence of fill quantity of fuel chamber

0

50

100

150

200

250

300

350

400

450

0% 20% 40% 60% 80% 100%

fill quantity of fuel chamber

ignitionstable burning

burnout

0

50

100

150

200

250

300

350

400450

0% 20% 40% 60% 80% 100%

fill quantity of fuel chamber

combustion phases > whole batch

150 mg/mn3 @ 13 Vol.-% O2 = 100 mg/MJ

mg/mn

3@1

3Vol.-%O2

mg/MJ

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Influence of operation on PM emissions

Operation of

Best case

Sufficient oxygensupply, small logs

Typically operated

Large amount oflarge logs

Worst case

Air inlet reducedor shut

wood stove

PMmg/m3

@13 Vol.-% O2

20 50 250 up to 2 500

Nussbaumer et al. 2008


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Emissions: Natural draft versus constant draft

Measurements with constant draft do not indicate PMemissions in practice. Natural chimney draft leads to higheremissions during ignition.

0

50

100

150

200

250

Ignition Stable Operation Burnout

PM

[mg/mn

3]

12 Pa Draft

Natural Draft

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0

500

1000

1500

2000

2500

3000

3500

[mg/mN3]

SP at 160C Condensable Particles

Condensable fraction of emissions

1.566311CP:SP (start-up)

5type-test

4i. from the bottom

warm startcold start

1 2 3ignition from the top


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1. Introduction

2. Objectives

3. Method

4. Results

5. Conclusions

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Conclusions

The start-up phase strongly contributes to the total PM butis not considered in nowadays type-tests.

Igniting the fire from the top can reduce PM emissions ofwood stoves

The operation type has a very strong influences on PMemissions. Nowadays type-tests and labels should rewardstoves which minimize the influence of the user.

Under typical burning conditions, high concentrations oforganic condensables are emitted which are not trapped inhot filter sampling

Condensables are likely to be correlated to hydrocarbonsmeasured by FID. Preliminary measurements show areasonable correlation between FID and impingers, whichis further investigated


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Acknowledgments

Swiss Federal Office for EnergySwiss Federal Office for the Environment

LiebiSchmidSigmaticTibaTonwerk Lausen

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Literature

Klippel, Nussbaumer: Feinstaubbildung in Holzfeuerungenund Gesundheitsrelevanz von Holzstaub im Vergleich zuDieselruss. 9. Holzenergie-Symposium, Zrich, 2006.

Vock, Jenni: Emissionsarme Anfeuermethoden frStckholzfeuerungen, 2007.

Nussbaumer, Doberer, Klippel, Bhler, Vock: Influence ofignition and operation type on particle emissions fromresidential wood combustion. 16th European BiomassConference, Valencia, 2008.

inflence of ignition on particle emission from residential wood combustion

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