Comparison of Overall OCM Kinetic Modeling by Genetic and Marquardt Algorithms

Gas phase kinetic studies on the oxidative coupling of methane, OCM, have been conducted in a tubular fixed bed reactor, using perovskite titanate as the reaction catalyst. The suitable operating conditions were found to be: temperature between 750-775 Cْ, total feed flow rate of 160 ml/min, CH4/O2 ratio of 2 and GHSV of 100 min-1. Six models have been selected among the overall common kinetic models. The selected models have been regressed with the experimental data which obtained from the Catatest system. Correlation of the kinetic data have been performed with lumped rate equations for C2 and COX formation as functions of temperature, O2 and CH4 partial pressures. The kinetic coefficients in the gas phase overall reactions were optimized by different numerical optimization methods such as: the Levenburg-Marquardt and genetic algorithms and the results were compared with each other. It has been found that the Santamaria model is in good agreement with the experimental data. It should be noted that the Marquardt algorithm is sensitive to the first guesses and there is possibility to trap in the relative minimum.

کلیدواژه ها:

OCM ، Kinetics ، Overall reactions ، Marquardt ، Genetic Algorithm