Characteristics and interactions between coal and carbonaceous wastes during co-combustion

This work focuses on the combustion characteristics of an Australian coal, a suite of carbonaceous materials, and their blends. A drop in both ignition temperature and burnout temperature was observed when carbonaceous wastes were blended with coal at different proportions (10 wt% and 30 wt%). The ignition index values of coal/polystyrene and coal/oat straw blends increased by 78% and 52%, respectively when the blending ratio increased from 10 wt% to 30 wt%. Similarly, 2.6 times increase in combustion index was also observed in coal/oat straw blend due to a large increase of mass loss rate contributed by the devolatilisation of oat straw. The significant drop in both peak and burnout temperatures for all the blends studied in this research demonstrated that there were strong interactions during the co-processing of coal with carbonaceous materials, which could be quantified by the root mean square interaction index (RMSII). It was found that coal/oat straw and coal/polystyrene blends had the highest RMSII values, which indicated the presence of strong interactions between coal and oat straw/polystyrene in the blends during co-combustion.