FINE PARTICLE EMISSIONS FROM PEAT AND WOOD FUELLED FLUIDIZED BUBBLING BED COMBUSTION

摘要

Fine particle emissions from a 66 MW (thermal) peat and wood fuel (wood chips, bark and sawdust) fired fluidized bed boiler, equipped with electrostatic precipitator (ESP), was studied. Both the mass and the number concentrations and size distributions of fine particles were measured in order to compare the emission levels between wood, peat and co-combustion. Carbon monoxide, nitrogen and sulfur dioxide emissions were considered as well. As regards to the measured fine particle (PM2.5 and PM10) mass concentrations, no big differences between peat and wood combustion occurred, but the number concentrations were quite different. In wood combustion the number concentration was far higher. This is mainly due to the different composition of peat and wood fuel ashes. Wood burning yields double peak shaped particle size distribution, first top locating at the range 0.1... 1 mm, just where ESP penetration is high. Replacing 30 % of wood fuel by peat reduced the particle number yield from wood burning remarkably. Compared to the reported emissions from combustion of coal and black liquor the measured fine particle mass emission levels were low.