MORPHOLOGICAL DEVELOPMENT OF RICE-HULL-DERIVED CHARCOAL IN A FLUIDIZED-BED REACTOR

Rice hull, a by-product of the rice milling industry, can be a potential fuel for energy self-sufficiency in the rice mills of the developing countries because of its high energy content. Nevertheless, little has been done to gasify this material because of various difficulties involved; such difficulties include high ash content and irregular geometry. Fluidized-bed gasification has been proposed as a useful method for biomass energy resource conversion. The gasification process is a heterogeneous reaction with a solid reactant which changes geometrically as conversion progresses. The use of a fluidized-bed reactor for rice-hull conversion has been proposed as well; however, it appears that the kinetics of the gasification process have not been studied extensively. In the present work, the development of the morphology of the rice-hull charcoal or char has been characterized by observing the changes in the surface areas, surface fractal dimensions and pore sizes at various temperatures of the devolatilization process in a fluidized-bed reactor. The results, which show the highly porous network of the microstructure, are relevant and applicable to the simulation of the reaction kinetics of rice-hull conversion.