Kinetic study and reactor modeling of ethylene oxychlorination

Abstract

Oxychlorination of ethylene to 1,2-dichloroethane is a vital step in the production of polyvinyl chloride. Polyvinyl chloride is a plastic polymer that is widely used, especially in construction. The reaction is usually catalyzed over a CuCl2/γ-Al2O3 catalyst. The neat catalyst is volatile and have limited activity. The addition promoters, mainly alkali metals and rare earth metals have shown to have an advantageous effect on the stability, selectivity and activity of the catalyst. The kinetic of the reaction is complicated as the catalyst changes from CuCl2 to CuCl and back again during the reaction. The dynamics of the catalyst causes complications when developing kinetic reaction models.

A kinetic model previously developed which utilizes the oxidation state of the catalyst was implemented in three different pseudo-homogeneous reactors: A dynamic laboratory scale reactor, a steady state industrial reactor and a steady state industrial test reactor which contains additional experimental data. The reactor simulations for the laboratory reactor and industrial reactor were done with kinetics from a neat catalyst and a Kpromoted catalyst. The industrial test reactor were only simulated with the K-promoted catalyst.

The simulations for the laboratory scale reactor matched well with the experimental values. The model was able to predict the spatial-time Cu2+ decently well for both catalysts. However due to lack of reliable experimental data the validation of the model is uncertain. The industrial scale simulations are hard to validate as the experiments are done for different catalysts from the simulated. Some modifications are believed to be needed and preferably the model should be made heterogeneous to give best results.