Kinetics of deactivation of a reforming catalyst during methylcyclohexane dehydrogenation in a diffusion reactor

The deactivation of a commercial reforming catalyst having 0.6% Pt supported on γ-alumina was studied in a single pellet diffusion reactor using the dehydrogenation of methylcyclohexane to toluene reaction as a model of the reforming process. The reaction was studied in the temperature range 350–400 °C and methylcyclohexane and hydrogen partial pressure from 15–60 and 0–800 Torr, respectively. In this range of concentrations, the reaction is approximately first order with respect to MCH and H2. Results of this work establish the sensitivity of the poisoning rate to hydrogen partial pressure in agreement with previous work. It is shown that only a part of the intermediate poison structures can be removed by hydrogenation under reaction conditions. A model of the poisoning process is developed which explains the data quantitatively, and agrees with previous work in important aspects.