CFD Modeling of Oxidative Coupling of Methane on Pellet Scale: Optimum Temperature

Document Type : Research Paper

Authors

1 Faculty of Chemical Engineering, Islamic Azad University Tehran South Branch

2 Iran Polymer and Petrochemical Institute

Abstract

This study presents the phenomena occuring in small scale single-pellet for the oxidative coupling of methane (OCM) where heat transfer plays an important role. Computational fluid dynamics (CFD) is used as a tool for obtaining detailed rate and temperature profiles through the porous catalytic pellets where reaction and diffusion are competing. Inter particle temperature and concentration gradients are taken into account by solving heat transfer coupled with continuity equations in the catalyst pellet. In the heat transfer equation, a source term of energy due to high exothermic reactions is considered. Subsequent to achieving this goal, two external programs are successfully implemented to the CFD code as kinetic and heat of reaction terms. The influence of reaction temperature on catalytic performance is studied. This study is based on the experimental design which is conducted in a differential reactor using an Sn/BaTiO3 catalyst (mesh 7-8) at atmospheric pressure and different temperatures of 1023, 1048 and 1073 K with a GHSV value of 12000 h-1 and a methane to oxygen ratio of 2. Based on the results for titanate perovskite catalyst, the highest C2 yield in OCM process is obtained at a temperature of 1048 K. The results of CFD simulation indicate that temperature variation within the catalyst pellet is less than 2 K due to the completion of exothermic oxidation reactions. Also, the results show that exothermic oxidation reactions occur before endothermic coupling reaction in the pellet length. The modeling results such as selectivity and conversion at the pellet exit are in good agreement with the experimental data

Keywords

References

منابع
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Journal of Petroleum Research
Volume 22, Issue 71 - Serial Number 71
November and December 2012
Pages 104-116

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