Continuous production of H<SUB>2</SUB> at low temperature from methane decomposition over Ni-containing catalyst followed by gasification by steam of the carbon on the catalyst in two parallel reactors operated in cyclic manner

CO-free H2 in close to stoichiometric amounts was produced continuously at a constant H2 production rate by the stepwise steam reforming of methane at low temperature (500&#176;C) in two parallel catalytic reactors operated in cyclic manner. The process involved two simultaneous reactions: first, catalytic decomposition of methane to H2 and carbon (deposited on the catalyst), and second, gasification of the carbon deposited on the catalyst by steam to H2 and CO2. The two reactions were carried out separately in two parallel reactors (both containing the same Ni-containing catalyst), operated in cyclic manner by switching a methane-containing feed and a steam-containing feed between the two reactors at a predecided interval of time. The process shows best performance at an optimum value of the feed switchover time. Among the different Ni-containing metal oxide (ZrO2, MgO, ThO2, CeO2, UO3, B2O3 or MoO3) and zeolite [HZSM-5, H&#946;, HM, NaY, Ce(72)NaY, or Si-MCM-41] catalysts, the Ni/ZrO2 and Ni/Ce(72)NaY showed promising results for the cyclic process