CO2 reforming of methane in a molten carbonate salt bath for use in solar thermochemical processes

CO2 reforming of methane was studied by bubbling a CH4/CO2 mixture in a molten salt bath of alkali-metal carbonate mixture (Na2CO3/K2CO3) containing suspended metal catalyst powder at 1223 K, Ni, Fe, Cu, or W metals, supported on an Al2O3 support were examined for activity and selectivity. The most active and selective catalyst was the Ni/Al2O3 catalyst. The methane conversion increased with an increase in the W/F ratio (W = weight of the molten salt bath containing the Ni/Al2O3 catalyst, and F = flow rate of CH4/CO2 mixture). About 70% of methane conversion was obtained at a W/F ratio of 0.25 g min cm(-3), in which the H-2/CO ratio in the product gas was approximately the stoichiometric ratio of one. This technique will be applied to the solar thermochemical methane reforming for converting solar high-temperature heat to chemical fuels, to give stable operations under fluctuation of insolation and thermal uniformity in the solar reformer under concentrated solar irradiation.