Energy Fuels 2011, 25, 315–323 Published on Web 01/05/2011
: DOI:10.1021/ef1007787
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Stove Performance and Emission Characteristics in Residential Wood Log and Pellet Combustion, Part 2: Wood Stove Esbj€ orn Pettersson,†,‡ Christoffer Boman,*,§ Roger Westerholm, Dan Bostr€ om,§ and Anders Nordin§ Energy Technology Centre, Box 726, SE-941 28 Pitea˚, Sweden, ‡Division of Energy Engineering, Lulea˚ University of Technology, SE-971 87 Lulea˚, Sweden, §Energy Technology and Thermal Process Chemistry, Umea˚ University, SE-901 87 Umea˚, Sweden, and Department of Analytical Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden )
†
Received June 21, 2010. Revised Manuscript Received October 15, 2010
The characteristics and quantities of a large number of gaseous and particulate emission components during combustion in a residential wood log stove with variations in fuel, appliance and operational conditions were determined experimentally. The measurement campaign included CO, NOx, organic gaseous carbon (OGC), volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), total particulate matter (PMtot) as well as particle mass and number concentrations, size distributions, and inorganic composition. CO varied in the range of 1100 to 7200 mg/MJfuel, while OGC varied from 210 to 3300 mg/MJfuel. Dominating VOCs were methane, followed by ethene, acetylene, and benzene. Methane varied from 9 to 1600 mg/MJfuel. The nonmethane volatile organic compound (NMVOC) emissions were in the range of 20-2300 mg/MJfuel. The PAHtot emissions varied from 1.3 to 220 mg/MJfuel, in most cases dominated by phenantrene, fluoranthene, and pyrene. PMtot were in all cases dominated by fine particles and varied in the range 38-350 mg/MJfuel. The mass median particle diameters and the peak mobility diameters of the fine particles varied in the range 200-320 and 220-330 nm, respectively, and number concentrations in the range of 1-4 1013 particles/MJfuel. Air starved conditions, at high firing intensity, gave the highest emissions, especially for hydrocarbons. This type of condition is seldom considered, though it may occur occasionally. The emissions from Swedish wood stoves, comparing a Swedish field study, are covered fairly well with the applied methodology, but other field studies report considerably higher emissions especially for diluted particle sampling.
implications to human health.8 Emissions of fine particles have been shown to be detrimental to health based on epidemiological studies.9 Wood log stoves are common RWC appliances used largely in cold climate. They are batch fired, which gives varying emissions during different phases in the combustion cycle. The performance is heavily influenced by the operator. Several studies have therefore shown that the emissions from wood log stoves can vary substantially, depending, e.g., on fuel and operation parameters.10-12 There are studies with extensive characterization of emissions, e.g., McDonalds et al.10 and Hedberg et al.,13 but few of them include both gaseous and particulate compounds as well as characterization of the PM with variations in a single wood stove as this work. The present work had the objective to experimentally determine the characteristics and quantities of a large number of gaseous and particulate emission components during combustion in a residential wood log stove with variations in fuel, appliance, and operational conditions. Another objective was to evaluate if it is possible to cover the range of observed
1. Introduction Residential wood combustion (RWC) is considered to be a major source of ambient air pollution in many urban areas and the potential adverse health effects of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and particulate matter (PM) have been of special concern.1-4 Compared to modern biomass combustion technologies, the majority of the presently used RWC heating devices often suffer from poorly optimized conditions, resulting in considerable emissions of products of incomplete combustion (PICs), e.g., CO, hydrocarbons, and carbonaceous soot particles. It has been shown5-7 that the PM emitted from these kind of small combustion devices are dominated by submicrometer sized (
