introduction: challenges in going from testbench results

3 Dec 2015

HELGE RØRDAM OLESEN

DEPARTMENT OF ENVIRONMENTAL SCIENCE

AARHUS UNIVERSITY AU

Introduction: Challenges in going from testbench results to emissions in the real world Helge Rørdam Olesen

3 Dec 2015




Introduction to the seminar

The seminar is intended as a catalyst for idea development and possibly later project development among the participants of the seminar.

We – the organizers - do not have a fixed outcome of the seminar in mind, but we are prepared to follow up on ideas that emerge.

You are all encouraged to contribute to discussions during the day.

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Practicalities

Slides from presentations will be made available on a web page – possibly not for all presentations

Voice recorder

Signs: Time out

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Quantification of emission from residential wood combustion

Challenges

Emission factors

There is no Danish national registry of wood stoves

Wood consumption is not well known

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Emission factors measured in private homes – PM2.5

Marianne Glasius, Ole Schleicher and others

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Emission factors measured in private homes – PM2.5

0

1000

2000

3000

4000

5000

ID 1 ID 2 ID 4 ID 5 ID 6 ID 7 ID 8 ID 9 ID 10 ID 11 ID 12 ID 13

g PM

2.5/G

J

Data from Glasius et al. 2005 & 2007 (DMU Arbejdsrapport 212 & 235).

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Emission factors – 3 substances

0

5

10

15

20

25

1A 1B 1C 2A 2B 3A 3B 4A 4B 5A 5B 6A 6B 7A 7B 8A 8B 9A 9B 10A 10B 11A 11B 12A 12B 13A 13B

partikler (g/kg træ)

0

50

100

150

200

250

300

350

400


mgPAH/kg træ

0

20

40

60

80

100

120

140

160


ng I-TEQ/kg træ

Particles

Dioxin

PAH

Source: Glasius et al. 2007 (DMU Arbejdsrapport 235).

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Usual practice for emission inventories

For a given combustion technology, emissions are assumed proportional to the amount of wood consumed.

Obviously a gross simplification!

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A previous presentation...

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TFZ has examined combustion conditions

Moisture content in firewood

Log size

Various types of wood: Beach, spruce, briquettes

Various loads

Type tests versus tests to simulate practical use

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Particle emission: Importance of measuring method – and of moisture content in wood

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Log size

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Particle emission: Importance of log size – and of measuring method

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PM (dry), dependency on combustion conditions

Red bars represent regular combustion (whereas blue

are ”inflaming”)

For red bars: Factor of 2.5 between worst and best.

Note: The factor would be larger if we considered PM (wet)

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PAH

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PAH Toxicity Equivalent [μg/MJ]

BL: Beach Log, 15% humidity (6)

BLOL: Beach Log, Overload (500)

SL: Spruce Log (160)

BLOD: Beach Log, Oxygen Deficiency (120)

Beach Log, 19% humidity (37)

SB: Spruce Briquette (8.7)

Pellet boiler (0.12)

Factor 80

We don’t speak about factor of two

differences...

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Relation between PM and levoglucosan

Levoglucosan content in PM (percent of mass):

For dry wood (beach with 15% moisture, optimal combustion): 1%

For less dry wood (19% moisture): 13%

Further results from Orasche et al. (2012)

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Studies on combustion conditions – lessons to learn

There are numerous challenges.

It is important to be well aware of the challenges. If they are neglected we may draw wrong conclusions and adopt inappropriate solutions.

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A factor that is sometimes neglected: Stacks

Stacks are important; generally the entire interaction between wood stove, stack and house deserves attention

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Some challenges to be pursued

It is a grossly simplifying assumption that for a given combustion technology, emissions are proportional to the amount of wood consumed. Today we should look deeper into this assumption and its implications.

When we make the simplifying assumption of proportionality, which dangers should we be aware of?

What are the reasons for the large variations in emissions? There are variations from stove to stove and from day to day. When considering different substances, the variations are not concurrent. We should discuss the factors that matter.

Can we identify heavy polluters?

Can we identify measures to avoid heavy polluters?

Let’s use this seminar to shed light on the challenges.

introduction: challenges in going from testbench results

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