Oxy-CO₂ reforming of methane to syngas over CoO_x/CeO₂/SA-5205 catalyst

Abstract

The oxy-CO₂ methane reforming (OCRM) process has been investigated over the CoO_x/CeO₂/SA-5205 catalyst at varying reaction temperatures (750-900°C), O₂/CH₄ ratios (0.3-0.45), and space velocities (20000-100000 cm³/g/h). With an increasing OCRM reaction temperature, the contribution from the CO₂ methane reforming reaction increased while that from methane combustion reactions decreased. Correspondingly, there was an increase in the H₂/CO ratio and a sharp decrease in reaction exothermicity. At 900°C (gas hourly space velocity = 46000 cm³/g/h and O₂/CH₄ = 0.4), the OCRM reaction over the CoO_x/CeO₂/SA-5205 catalyst was mildly endothermic with >90% CH₄ conversion, >95% H₂ selectivity, and a H₂/CO ratio of 1.63. CH₄ conversion was relatively unaffected by the O₂/CH₄ ratio used in the OCRM reaction; however, CO₂ conversion decreased on increasing the O₂/CH₄ ratio. While H₂ selectivity was not significantly affected by the O₂/CH₄ ratio, the H₂/CO ratio increased linearly with an increasing O₂/CH₄ ratio. The endothermicity of the reaction was found to decrease with an increasing CH₄/O₂ ratio, which can be explained on the basis of increased contribution from the methane partial oxidation reaction with an increasing O₂/CH₄ ratio.