摘要
CeO2 oxygen carrier was prepared by precipitation method and tested by two-step steam reforming of methane （SRM）. Two-step SRM for hydrogen and syngas generation is investigated in a fixed-bed reactor. Methane is directly converted to syngas at a H2/CO ratio close to 2 ： 1 at a high temperature （above 750 °C） by the lattice oxygen of CeO2; methane cracking is found when the reduction degree of CeO2 was above 5.0% at 850 °C in methane isothermal reaction. CeO2？δ obtained from methane isothermal reaction can split water to generate CO-free hydrogen and renew its lattice oxygen at 700 °C; simultaneously, deposited carbon is selectively oxidized to CO2 by steam following the reaction （C＋2H2O→CO2＋2H2）. Slight deactivation in terms of amounts of desired products （syngas and hydrogen） is observed in ten repetitive two-step SRM process due to the carbon deposition on CeO2 surface as well as sintering of CeO2.
CeO2 oxygen carrier was prepared by precipitation method and tested by two-step steam reforming of methane （SRM）. Two-step SRM for hydrogen and syngas generation is investigated in a fixed-bed reactor. Methane is directly converted to syngas at a H2/CO ratio close to 2 ： 1 at a high temperature （above 750 °C） by the lattice oxygen of CeO2; methane cracking is found when the reduction degree of CeO2 was above 5.0% at 850 °C in methane isothermal reaction. CeO2？δ obtained from methane isothermal reaction can split water to generate CO-free hydrogen and renew its lattice oxygen at 700 °C; simultaneously, deposited carbon is selectively oxidized to CO2 by steam following the reaction （C＋2H2O→CO2＋2H2）. Slight deactivation in terms of amounts of desired products （syngas and hydrogen） is observed in ten repetitive two-step SRM process due to the carbon deposition on CeO2 surface as well as sintering of CeO2.
基金
supported by the National Natural Science Foundation of China (NO. 51004060)
the Natural Science Foundation of Yunnan Province (NO. 2008E030M, 2010ZC108)
the Research Foundation for the Doctoral Program of Higher Education of China (NO. 20095314120005)
the Analysis and Test Foundation of Kunming University of Science and Technology (KUST)
the 2010 Innovation Foundation of KUST
