Pyrolysis of rice husk

Rice husk has proved to be a difficult fuel for gasification and fluidized bed combustion because of the high ash content resulting in carbon conversion inefficiency. We report the results of pyrolysis experiments of individual rice husk particles under controlled atmospheres of the confocal scanning laser microscope followed by SEM observations of the pyrolized structure of the particles. The results suggest a preferential shrinkage of the particles in the transverse direction, implying the presence of strong and inert silica layer that retains its structure despite high temperatures. The cellulose and lignin component was preferentially consumed in geometrically arranged pores and channels. The role of silica appears to be more than just a geometric shield and thus complete carbon conversion may not be achievable.