Pyrolysis of blends of biomass with poor coals

This paper reports on the pyrolytic behaviour of three different kinds of solid fuel and their blends in order to understand and further improve the performance of fluidized bed gasification of biomass-poor coal blends. Individual feedstocks consisting of pine chips, black coal and waste coal and several biomass-coal blends were pyrolysed in a thermobalance apparatus at atmospheric pressure. Experiments were carried out dynamically by increasing the temperature from 110 to 900 degrees C with a heating rate of 100 K min(-1). The data show very poor behaviour of the waste coal compared with pine chips and even black coal. Nevertheless, when a minimum of 40% of pine chips was blended with 60% waste coal and pyrolysed under the same conditions, the rate of mass loss increased sharply and was similar to that of black coal. D.t.g. results indicate that the main pyrolysis processes can be quantitatively expressed in terms of C-0 = C(w)e(-kt) for both the individual fuels and the blends. Additional studies showed that no interaction takes place between biomass and coal in a blend during pyrolysis.