The mechanism characterizations of methane steam reforming under coupling condition of temperature and ratio of steam to carbon

To elucidate the coupling effects of temperature and ratio of steam to carbon on the methane steam reforming process, the characterizations of methane steam reforming at different temperature and ratio of steam to carbon in term of distribution of H2 and CO, and the elementary reaction rate were investigated. Meanwhile, the formation mechanisms of H2 and CO via sensitivity analysis and reaction path analysis were obtained. The results showed that the coupling effects of temperature and ratio of steam to carbon on the methane steam reforming were higher than that of individual factor. The effects of temperature on the methane steam reforming were higher than that of the ratio of steam to carbon. The adsorption and desorption reaction of CH4 on the surface of Ni-based catalyst had the most obvious effect on the sensitivity of H2, CH4 and CO. Besides, the effects of adsorption and desorption reaction of H2O on the sensitivity of H2 were higher than that of CH4 and CO. Hydrogen was generated by the desorption reaction of H(s) in the adsorbed state and from three generating paths: a) CH4(s) dissociated directly or reacted with O(s) to form H(s); b) The dissociation reaction of H2O(s) produced H(s); c) OH(s) dissociated directly or reacted with C(s) to form H(s). Carbon monoxide was generated from single path: CH4(s)→CH3(s)→CH2(s)→CH(s)→C(s)→CO(s)→CO(g).