A study of CO2 reforming of CH4 for coal delivered gases over Ni-based catalysts

Abstract

NiCo-Mg/Al-1.7, Ni-Mg/Al-1.6, Ni-Mg/Al-0, and NiCo-Mg/Al-0.3 Ni-based catalysts were used to test their performance in CO2 reforming of CH4 reaction for a coal gas feed mainly containing CO and H2 as well as CO2 and CH4 at 900°C and the ambient pressure. Compared to the performance in ideal feed of CO2 and CH4 balanced with N2, the smaller reaction rate in the coal gas observed over all the catalysts was barely due to the lower concentration of CO2 and CH4 in the feed. NiCo-Mg/Al-1.7 catalyst showed the highest activity and stability among the four catalysts owing to its right metallic NiCo alloy sites to activate CH4 and the strong basic sites to activate CO2. The TPO of the spent catalyst after 24h TOS showed no carbon formation. The other three catalysts facilitated more or less various formats of carbon formation depending on different surface properties, leading to the decay of catalytic activity along the TOS. The coal gas feed that contains very small amount of O2 helped mitigate the formation of the inactive graphitic carbon, possibly because O2 burned the carbon of this kind. This study will improve the efficiency of using coal gas by converting its to-be-emitted CO2 and CH4 into valuable CO and H2.