Kinetic modelling of methanol synthesis over commercial catalysts: A critical assessment

Abstract

Kinetic modelling of methanol synthesis over commercial catalysts is of high importance for reactor and process design. Literature kinetic models were implemented and systematically discussed against a newly developed kinetic model based on published kinetic data. Deviations in the sensitivities of the kinetic models were explained by means of the experimentally covered parameter range. The simulation results proved that an extrapolation of the working range of the kinetic models can lead towards significant simulation errors especially with regard to pressure, stoichiometric number and CO/CO2-ratio considerably limiting the applicability of kinetic models frequently applied in scientific literature. Therefore, the validated data range for kinetic models should be considered when detailed reactor simulations are carried out. With regard to Power-to-Methanol processes special attention should be drawn towards the rate limiting effect of water at high CO2 contents in the syngas. Moreover, it was shown that kinetic models based on data measured over outdated catalysts show significantly lower activity than those derived from state-of-the-art catalysts and should therefore be applied with caution for reactor and process simulations. The plausible behavior of the herein proposed kinetic model was demonstrated by a systematic comparison towards established kinetic approaches within both, an ideal kinetic reactor and an industrial steam cooled tubular reactor. Relative to the state-of-the-art kinetic models it was proven that the herein proposed kinetic model can be applied over the complete industrially relevant working range for methanol synthesis.