Abstract
To raise the co-firing rate of the woody biomass is one method for CO_2 reduction in pulverized coal power stations. Since the carbonization of raw woody biomass can improve the grindability in the mill, it is possible to use in higher mixing rate of biomass. CRIEPI investigated the carbonization of cedar and Melaleuca in trust study from Ministry of the Environment. In this study, the grindability of carbonized fuel mixed with coal was evaluated by a test roller mill. And the combustion characteristics of carbonized fuel mixed with coal was investigated by a small scale coal combustion test facility with a single burner. The mixing rate of carbonized fuel with coal was 30% at the maximum on the basis of heat value. In grinding tests, it was confirmed that the grindability of cedar and Melaleuca was improved by carbonization. In combustion tests, NOx and SO_2 emissions, the unburned carbon concentration in fly ash and the combustion efficiency of combustible matter were evaluated.
