Stove Performance and Emission Characteristics in Residential Wood Log and Pellet Combustion, Part 1: Pellet Stoves

Abstract

Stove performance, characteristics, and quantities of gaseous and particulate emissions were determined for two different pellet stoves, varying fuel load, pellet diameter, and chimney draft. This approach aimed at covering variations in emissions from stoves in use today. The extensive measurement campaign included CO, NO x , organic gaseous carbon, 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. At high load, most emissions were similar. For stove B, operating at high residual oxygen and solely with primary air, the emissions of PMtot and particle numbers were higher while the particles were smaller. Lowering the fuel load, the emissions of CO and hydrocarbons increased dramatically for stove A, which operated continuously also at lower fuel loads. On the other hand for stove B, which had intermittent operation at lower fuel loads, the emissions of hydrocarbons increased only slightly lowering the fuel load, while CO emissions increased sharply, due to high emissions at the end of the combustion cycle. Beside methane, dominating VOCs were ethene, acetylene, and benzene and the emissions of VOC varied in the range 1.1−42 mg/MJfuel. PAH emissions (2−340 μg/MJfuel) were generally dominated by phenanthrene, fluoranthene and pyrene. The PMtot values (15−45 mg/MJfuel) were in all cases dominated by fine particles with mass median diameters in the range 100−200 nm, peak mobility diameters of 50−85 nm, and number concentrations in the range 4 × 1013 to 3 × 1014 particles/MJfuel. During high load conditions, the particulate matter was totally dominated by inorganic particles at 15−25 mg/MJfuel consisting of potassium, sodium, sulfur, and chlorine, in the form of K2SO4, K3Na(SO4)2, and KCl. The study shows that differences in operation and modulation principles for the tested pellet stoves, relevant for appliances in use today, will affect the performance and emissions significantly, although with lower scattering in the present study compared to compiled literature data.

Continental anthropogenic primary particle number emissions

“…Additionally, the emission factors for diesel-fuelled road transport were made dependent on the fuel sulphur content (FSC), based on vehiclespecific FSC dependent emission factors provided by the Laboratory of Applied Thermodynamics at the Aristotle University of Thessaloniki, which is responsible also for the TRANSPHORM database. Also EF PN s and PSDs for domestic wood combustion (including pellet burning and medium size district heating boilers) and for shipping emissions (fuel sulphur content-dependent EF PN s and PSDs) were updated (domestic sector: Gaegauf et al, 2001;Hedberg et al, 2002;Johansson et al, 2004;Johansson et al, 2008;Kinsey et al, 2009;Lack et al, 2009;Lamberg et al, 2011;Bäfver et al, 2011;Boman et al, 2011;Pettersson et al, 2011;Chandrasekaran et al, 2011;shipping: Hobbs et al, 2000;Sinha et al, 2003;Petzold et al, 2008;Murphy et al, 2009;Moldanova et al, 2011;Diesch et al, 2013), as well as for two-stroke vehicles in road transport Etissa et al, 2008). A new PSD was introduced also for flaring in gas and oil industry (Canteenwalla et al, 2006).…”

Correlation between air flow rate and pollutant concentrations during two-stage oak log combustion in a 25 KW residential boiler

“…Similar studies examining pollutant emissions using wood log fired boilers with a heat output of approx 20 kW were previously conducted (Boman et al, 2011;Johansson et al, 2004;Kjallstrand et al, 2004 cpe.czasopisma.pan.pl; degruyter.com/view/j/cpe and Olsson et al, 2006). However, these experiments were performed in laboratory conditions in controlled stationary states, in most cases obtaining lower pollutant (mainly carbon monoxide) concentration results than would probably be achieved in real-life conditions.…”

Improved emission inventories of SLCP

“…In later years additional work has been published (e.g. Bafver et al, 2011, Boman et al, 2011. Swedish measurement experts have also participated in international efforts in comparing emission measurement standards and resulting emission factors for particulate matter (e.g.…”