EMISSIONS OF POLYCYCLIC AROMATIC HYDROCARBON PARTICULATES FROM COMBUSTION OF DIFFERENT FUELS

The use of biomass as fuel for combustion allows partial replacement of fossil fuels and the reduction of fossil carbon dioxide emissions. Nevertheless, combustion of biomass waste may generate toxic pollutants such as Polycyclic Aromatic Hydrocarbons (PAHs) whose production is related to the combustion temperature, oxygen consumption and origin of the biomass fuel. In the present study, experimental protocols for biomass combustion and analytical quantification of PAHs were carried out. Six types of fuel were burned in a tubular reactor: two bio-solids dried differently (air drying and fry drying), oil-shale, used cooking oil (for recycling) and two types of woody biomass (oak and beech). The combustion tests were performed at 850 degrees C with fixed bed samples weighing about 1 g. The identification and quantification of PAHs in the particulate phase were performed by ultrasonic extraction followed by high-resolution gas chromatography coupled to low-resolution mass spectrometry. The 16 main EPA-classified PAHs have been identified. The results show that emissions of fry-dried sludge are approximately 5000 mu g g(-1), thus 10 times greater than those of wood and 10 times lower than those of used cooking oils. Toxicity of the particulate phase was essentially due to benzo(a)pyrene and benzo(b)fluoranthene.