Thermochemical methane reforming using a reactive WO3/W redox system

The methane reforming process combined with metal oxide reduction was evaluated, for the purpose of converting solar high-temperature heat to chemicals below 1273 K. The metal oxide was endothermically reacted with methane, to produce CO, hydrogen and the component metal in the temperature range of 1173–1273 K. Of the metal oxide candidates, WO3 and V2O5 were found to be reactive and selective metal oxides for the purposes of methane reforming. The metallic tungsten produced by methane reforming could be used to split water and to generate hydrogen at a lower temperature of 1073 K. To improve the reactivities of WO3 for methane reforming and the subsequent splitting of water, supported tungsten oxides were examined in the temperature range of 1073–1273 K. The reactivities were much improved with the ZrO2-supported WO3, giving a methane conversion of 70% and a CO selectivity of 86%. Our findings indicate the possibility that the proposed two-step process using a WO3/W redox system may be a potentially new thermochemical path that produces useful energy carriers of processed metal, syngas and methanol for storing and transporting solar energy from the sun belt to remote population centers.