Simultaneous steam and CO2 reforming of methane to syngas over NiO/MgO/SA-5205 in presence and absence of oxygen

Steam reforming, CO2 reforming and simultaneous steam and CO2 reforming reactions of methane for its conversion into syngas (H-2 and CO) over NiO/MgO/SA-5205 catalyst (prepared by depositing NiO on MgO precoated SA-5205 support) have been investigated at different process conditions. In some cases O-2 was present in the feed, while in other cases it was not. The catalyst has been characterised by its temperature programmed reduction and also, after its reduction, by temperature programmed desorption of hydrogen. It showed high activity and selectivity in the above methane-to-syngas conversion reactions at low contact times. The H-2/CO product ratio in the simultaneous methane conversion reactions showed a strong dependence on the feed composition; such dependence is increased by increasing the concentration of steam relative to that of O-2 and/or CO2 in the feed. In the oxy-steam and/or CO2 reforming reactions, there is a direct coupling of the exothermic and endothermic reactions and hence these processes over the catalyst occur in the most energy efficient and safe manners, requiring little or no external energy. The net heat of reactions in these processes is strongly influenced by the reaction temperature and/or CH4/O-2 ratio in the feed. In the simultaneous steam and CO2 reforming of methane in both the presence and absence of O-2, it is possible to convert methane into syngas with high conversion (above 97%) and 100% selectivity for both CO and H-2. (C) 1998 Elsevier Science B.V.