Kinetic Modelling of Propane Dehydrogenation over a Pt–Sn/hierarchical SAPO-34 Zeolite Catalyst, Including Catalyst Deactivation

Abstract

Pt–Sn/hierarchical SAPO-34 was synthesised and kinetically modelled as an efficient and selective catalyst for propylene production through propane dehydrogenation. The kinetics of the reaction network were studied in an integral fixed-bed reactor at three temperatures of 550, 600 and 650 °C and weight hourly space velocities of 4 and 8 h−1 with a feed containing hydrogen and propane with relative molar ratios of 0.2, 0.5 and 0.8, at normal pressure. The experiments were performed in accordance with the full factorial experimental design. The kinetic models were constructed on the basis of different mechanisms and various deactivation models. The kinetics and deactivation parameters were simultaneously predicted and optimised using genetic algorithm optimisation. It was further proven that the Langmuir–Hinshelwood model can well predict propane dehydrogenation kinetics through lumping together all the possible dehydrogenation steps and also by assuming the surface reaction as the rate-determining step. A coke formation kinetic model has also shown appropriate results, confirming the experimental data by equal consideration of both monolayer and multilayer coke deposition kinetic orders and an exponential deactivation model.