Agglomeration and fragmentation phenomena of bed materials and fuel particles during

The paper reports on a current research on fluidised bed gasification of biomass and coals. The focus is on the bed material agglomeration and fragmentation phenomena that are well known to affect the reliability and the efficiency of fluidized bed combustion processes. Preliminary results of dedicated tests at high temperature are reported and discussed in the paper. On the whole, agglomeration phenomena appear to be less relevant under gasification conditions than during combustion. Extensive fragmentation has been experienced for a bed of fresh or calcined dolomite, whereas other materials having catalytic properties (sintered dolomite, ?-alumina) are more suitable under this aspect. Attrition tests also confirm the lower mechanical resistance of the calcined dolomite.