Thermochemical methane reforming using WO3 as an oxidant below 1173 K by asolar furnace simulator

Thermochemical methane reforming by a reactive redox system of WO, was demo nstrated under direct irradiation of the metal oxide by a concentrated, sol ar-simulated Xe-lamp beam below 1173 K, for the purpose of converting solar high-temperature heat to chemical fuels. In the proposed cycling redox pro cess, the metal oxide is expected to react with methane as an oxidant to pr oduce syngas with a H-2/CO ratio of two, which is suitable for the producti on of methanol, and the reduced metal oxide which is oxidized back with ste am in a separate step to generate hydrogen uncontaminated with carbon oxide . The ZrO2-supported WO3 gave about 45% of CO yield and 55% of H-2 yield wi th a H-2/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 CHO. The activity data under the solar simulation were compare d to those for the WO3/ZrO2 heated by irradiation of an infrared light. Thi s comparison indicated that the CO selectivity was much improved to 76-85% in the solar-simulated methane reforming, probably by photochemical effect due to WO, phase. The main solid product of WO2 in the reduced WO3/ZrO2 was reoxidized to WO3 with steam to generate hydrogen below 1173 K. (C) 2001 E lsevier Science Ltd. All rights reserved.