Formation and emission of polycyclic aromatic hydrocarbon soot precursors during coal combustion

Abstract

AbstractThe polycyclic aromatic hydrocarbon (PAH) soot precursors present in flue gases from a number of coal fired appliances, ranging in capacity from a 325 MW power station to a domestic open fire, were collected by standard procedures in which both particulate and gas phase were sampled, and analysed by gas chromatography–mass spectrometry. The distribution of PAHs between particulate and vapour phase was determined. Emissions of two- and three-ring PAHs predominated, and there was a general trend of a reduction in emissions with increasing capacity. Polycyclic aromatic hydrocarbon emissions from a fluidised bed boiler were reduced when biomass was incorporated into the feed fuel. The environmental significance of the emissions was considered, and the levels of carcinogenic PAHs in the flue gas from a 325 MW power station were of the same order of magnitude as those in ambient city air. The contributions of different mechanisms to the formation of PAHs in different appliances were assigned from a comp...