Flow properties of biomass and coal blends

Co-firing of coal/biomass blends in the existing coal fired power plants is an attractive option for reducing the greenhouse emissions. However, fuel processing and handling problems associated with coal/biomass blends restrict the widespread application of the co-firing technology. In this study, flow properties of typical Australian coal and biomass as well as their blends were systematically studied. The flow property data obtained from this study provided an insight into the underlying phenomena responsible for some of the problems often encountered in handling of coal/biomass blends. The flow properties of the coal and biomass blends were found to be dependent upon the form of biomass being used. We found that blending coal with sawdust reduced the likelihood of flow stoppage because sawdust particles lowered the bulk strength (cohesive strength) of the mixture from that of coal alone while maintaining more or less the same frictional properties as the parent coal. On the contrary, blends of coal and woodchip exhibited frictional characteristics far greater than the parent coal while showing bulk strengths similar to coal. As such, blends of woodchips and coal were found to be more susceptive to flow stoppage.