A novel hydrogen/syngas production process: Catalytic activity and stability of [formula omitted

Abstract

A reformer using a circulating fluidized bed has been proposed for the production of hydrogen and syngas. A catalyst is circulated between two reactors for the catalytic decomposition of methane to hydrogen and carbon, and for the gasification of carbon deposited on the catalyst. Catalytic activities of Ni SiO 2 for both CH 4 decomposition and CO 2 gasification of deposited carbon were investigated at 873 – 1023 K in a periodically-operated fixed bed reactor. Carbon which had a moss-like morphology was hardly gasified and caused deactivation of the catalyst. Such a type of carbon became dominant with raising reaction temperature and with increasing amount of Ni loaded on SiO 2. In contrast, filamentous carbon which had a graphitic structure could be gasified with CO 2 and became dominant with decreasing amount of Ni loaded and with lowering reaction temperature. It was found that Ni(5 wt%) SiO 2 had a stable activity against the cycles of decomposition/gasification because Ni on Ni(5) SiO 2 was difficult to sinter at 873 K and as a result, the filamentous carbon was exclusively formed.