Catalytic gasification of rice hull.(II) the steam reforming reaction

Continuous steam reforming of rice hull in a fluidized bed reactor containing Ni catalyst has been studied; the effects of temperature, catalyst surface area and decay are presented. The gas yield is determined principally by the availability of active Ni surface and reaction temperature. The use of catalyst enables up to 1.8 std L of gas containing up to 65% H₂ to be produced from one gram of rice hull at reaction temperatures as low as 600-700°C. This yield approaches the thermodynamic equilibrium value for the reaction between steam and the primary intermediates of CH_1.88O_0.82. As the catalyst decays, the gas yield decreases gradually and of several possible mechanisms, coking and sulfur poisoning have been found to be the major factors for the catalyst decay.