| Abstract: | Thermochemical methane reforming by a reactive redox system of WO3 was demonstrated under direct irradiation of the metal oxide by a concentrated, solar-simulated Xe-lamp beam below 1173 K, for the purpose of converting solar high-temperature heat to chemical fuels. In the proposed cycling redox process, the metal oxide is expected to react with methane as an oxidant to produce syngas with a H2/CO ratio of two, which is suitable for the production of methanol, and the reduced metal oxide which is oxidized back with steam in a separate step to generate hydrogen uncontaminated with carbon oxide. The ZrO2-supported WO3 gave about 45% of CO yield and 55% of H2 yield with a H2/CO ratio of about 2.4 in a temperature range of 1080–1160 K at a W/F ratio of 0.167 g min Ncm−3 (W is the weight of WO3 phase and F is the flow rate of CH4). The activity data under the solar simulation were compared to those for the WO3/ZrO2 heated by irradiation of an infrared light. This comparison indicated that the CO selectivity was much improved to 76–85% in the solar-simulated methane reforming, probably by photochemical effect due to WO3 phase. The main solid product of WO2 in the reduced WO3/ZrO2 was reoxidized to WO3 with steam to generate hydrogen below 1173 K. |
