In many Eastern European countries the emission of pollutants from coal fired domestic and small commercial heating plants is a serious problem. One alternative method to reduce emissions is by burning coal with biomass that is by co-combustion, which would reduce the amount of net CO2 produced, the rate of reduction of coal reserves, and the overall amounts of pollutants. The effects of co-combustion of coal and biomass on the levels of pollutant formation have been studied for a 30 kW domestic boiler. Of particular interest are the emissions of PAH and VOC since it has been shown that these emissions are lowered during co-combustion.

The relation between boiler design fuel composition and measured emission profiles for VOC and PAH is discussed in detail. Outputs from modelling of the emissions and devolatilisation characteristics of the fuels have been compared to measured values. Analytical methods have been developed for characterisation of the initial devolatilisation products from both coal and biomass fuels and the relation to modelling is discussed. The fate of these initial devolatilisation products and the effect of boiler design on the formation of PAH and soot in the post combustion zones is addressed.