Particulate and gaseous emissions from manually and automatically fired small scale combustion systems

In an extensive wood combustion source test series 2 automatically and 2 manually fired appliances, and 8 fuel types were investigated with respect to their particulate (PM10) and gaseous emissions. Softwood briquettes, beech, oak and spruce logs, wood pellets as well as further biogenic fuels: wood chips, miscanthus (elephant grass) pellets and triticale (“energy crop”) pellets were tested. Gaseous emissions were measured continuously while PM10 was sampled with a dilution system and averaged over standard test cycles. Manually fired stoves exhibited highly variable emissions resulting in an uncertainty of 30% for most measured compounds, determined in a series of replicate experiments. Average PM10 emissions from manually fired appliances were around 130 mg m−3 (standard conditions for temperature and pressure (STP), 13%O2, dry gas), equivalent to 90 mg MJ−1. Wood pellets and chips combustion under full load operation with automatically fired appliances emit almost one order of magnitude less PM10, respectively: 12–21 mg m−3 (STP, 13%O2, dry gas), or 8–14 mg MJ−1.