[Stoves] Emissions from Residential Wood Combustion: Effect of Moisture on Emissions (2)

[Tom Miles]

Emissions from Residential Wood Combustion: Effect of Moisture on Emissions
Fernando Preto, Canmet Energy Technology Center, Canada, Paris, October 21,
2005
 <http://www.ieabcc.nl/meetings/task32_Paris_ssc/Preto.pdf>
http://www.ieabcc.nl/meetings/task32_Paris_ssc/Preto.pdf (1.3 MB pdf)
http://stoves.bioenergylists.org/en/canmetiea32paris
<http://stoves.bioenergylists.org/en/canmetiea32> 
 
In a presentation to the IEA (International Energy Agency) Bioenergy Task 32
Workshop: Recent Developments in Small Scale Combustion Devices, Fernando
Preto of Canmet showed the effect of moisture on emissions. 
 
Fuels were tested at Low Moisture (15%) and High Moisture (30%) for carbon
monoxide (CO), particulate matter (PM) and Volatile Organic Compounds (VOC).
 
Low Moisture (15% MC) produced high CO, low PM and low VOC.
 
High Moisture (30% MC) produced low CO, high PM and high VOC.
 
The purpose was to "Study hazardous emissions from residential wood
combustion devices in order to provide information for reducing the amount
of particulates, VOCs and dioxins and furans and update database of the
current contribution of residential appliances to Canadian air sheds." 
 
Environment Canada has initiated the process necessary for adoption of a
national regulation for emissions. British Columbia has adopted the US
standards. 
 
The presentation cites Canadian and US standards including:
CSA B415.1 (Cdn), EPA Part 40 (US): Test methods for determination of
efficiency and particulate emissions from wood fired appliances, including
conventional pellet stoves, inserts, central furnaces and boilers, small
commercial systems, and "high performance" fireplaces. Maximum particulate
emission levels are specified. An ASTM document is also being developed to
provide testing requirements for outdoor boilers (WK 5982).
 
The study found cordwood stove VOC emissions ranging from 38 mg/kg for
certified, hardwood, low moisture, high burn rate to 13 097 mg/kg fuel for
"old" stove, softwood, high moisture, low burn rate. 
 
Total particulate emissions ranged from 0.019 g/MJ for the pellet stove
operated at a high burn rate to 3.68 g/MJ for the "old" conventional stove
operated at a low burn rate. Average emissions are 1.68 g/MJ for the
conventional cordwood stove and 0.44 g/MJ for certified non-catalytic
stoves. 
 
Data show the clear reduction of 3:1 for PM through design.
 
It concludes:
 
- Advanced technology devices, such as pellet and certified cordwood stoves,
produce substantially less hazardous emissions than conventional cordwood
stoves.

- In general lower fuel moisture and high burn rates result in lower
emissions but there is no consistent effect on all hazardous emissions.  
 
IEA Bioenergy Task 32 Biomass Combustion and Cofiring  http://www.ieabcc.nl/
Canmet Residential/Commercial Combustion (Fernando Preto, Skip Hayden)
http://www.nrcan.gc.ca/es/etb/ctec/cetc01/htmldocs/Publications/factsheet_re
sidential_commercial_combustion_e.htm