Microkinetic and sensitivity analysis of oxidative dry reforming of methane on Ni–Co catalyst using a reaction mechanism based on Ni

Abstract

Microkinetic modelling of dry reforming of methane (DRM) with O₂ co-feed was performed using a previously developed reforming mechanism. The model was validated by comparing simulated results with experimentally determined data over a variety of reaction conditions. Numerically predicted results show that co-feeding O₂ improved CH₄ conversion, reduced carbon deposition, and increased H₂/CO ratio. Microkinetic analysis shows that during oxidative dry reforming of methane (ODRM), the surface coverage of empty sites tracks the CH₄ conversion. Furthermore, the H₂/CO ratio is directly related to the surface H* and CO* coverages. Sensitivity analysis highlighted that CH₄ dissociation is the rate-determining step for ODRM reaction, and the adsorption–desorption steps are equilibrated. We were able to obtain a reduced mechanism (35 steps) for ODRM by applying a previously suggested hierarchical chemistry reduction strategy on the full mechanism (52 steps). The apparent activation energy for CH₄ consumption and orders of the reaction were also determined.