CFD modeling of reaction and mass transfer through a single pellet: Catalytic oxidative coupling of methane

Abstract

In this study a mathematical model of a small scale single pellet for the oxidative coupling of methane (OCM) over titanite pervoskite is developed. The method is based on a computational fluid dynamics (CFD) code which known as Fluent may be adopted to model the reactions that take place inside the porous catalyst pellet. The steady state single pellet model is coupled with a kinetic model and the intra-pellet concentration profiles of species are provided. Subsequent to achieving this goal, a nonlinear reaction network consisting of nine catalytic reactions and one gas phase reaction as an external program is successfully implemented to CFD-code as a reaction term in solving the equations. This study is based on the experimental design which is conducted in a differential reactor with a Sn/BaTiO 3 catalyst (7-8 mesh) at atmospheric pressure, GHSV of 12000 h −1, ratio of methane to oxygen of 2, and three different temperatures of 1023, 1048 and 1073 K. The modeling results such as selectivity and conversion at the pellet exit are in good agreement with the experimental data. Therefore, it is suggested that to achieve high yield in OCM process the modeling of the single pellet should be considered as the heart of catalytic fixed bed reactor.