Simultaneous oxidative conversion and CO₂ or steam reforming of methane to syngas over CoO-NiO-MgO catalyst

Abstract

CO₂ reforming, oxidative conversion and simultaneous oxidative conversion and CO₂ or steam reforming of methane to syngas (CO and H₂) over NiO-CoO-MgO (Co: Ni: Mg=0.5: 0.5:1.0) solid solution at 700-850°C and high space velocity (5.1x10⁵ cm³ g^-1 h^-1 for oxidative conversion and 4.5x10⁴ cm³ g^-1 h^-1 for oxy-steam or oxy-CO₂ reforming) for different CH₄/O₂ (1.8-8.0) and CH₄/CO₂ or H2O (1.5-8.4) ratios have been thoroughly investigated. Because of the replacement of 50 mol% of the NiO by CoO in NiO-MgO (Ni/Mg=1.0), the performance of the catalyst in the methane to syngas conversion process is improved; the carbon formation on the catalyst is drastically reduced. The CoO-NiO-MgO catalyst shows high methane conversion activity (methane conversion >80%) and high selectivity for both CO and H₂ in the oxy-CO₂ reforming and oxy-steam reforming processes at ≥ 800°C. The oxy-steam or CO₂ reforming process involves the coupling of the exothermic oxidative conversion and endothermic CO₂ or steam reforming reactions, making these processes highly energy efficient and also safe to operate. These processes can be made thermoneutral or mildly exothermic or mildly endothermic by manipulating the process conditions (viz. temperature and/or CH₄/O₂ ratio in the feed).