CFD modeling of catalyst pellet for oxidative coupling of methane:Heat transfer and reaction

摘要

This study deals with the phenomena occuring at single-pellet catalyst scale for the oxidative coupling of methane where heat transfer plays an important role.Computational fluid dynamics(CFD) is used for obtaining detailed rate and temperature profiles through the porous catalytic pellet where reaction and diffusion compete.Intra-particle temperature and concentration gradients were taken into account by solving heat transfer coupled with continuity equations in the catalyst pellet.In heat transfer,the energy term due to highly exothermic reaction was considered.Two external programs were successfully implemented into the CFD-code as kinetic and heat of reaction terms.Simulation results showed that reaction was favored at the beginning for the pellet,followed by diffusion predomination.The results of CFD simulation indicate that temperature variation within the catalyst pellet is <2K due to exothermic oxidation.The results showed further that exothermic oxidation reactions occurred prior to endothermic coupling reaction in the pellet.