The Modeling of Kinetics and Catalyst Deactivation in Propane Dehydrogenation Over Pt-Sn/γ-Al_2O_3 in Presence of Water as an Oxygenated Additive

摘要

A reduction in catalyst's activity with time-on-stream and the formation of side products are two of the problems associated with catalytic propane dehydrogenation (PDH). Previous studies have indicated that the presence of small amounts of oxygenated additives such as water can reduce coke formation and enhance catalyst activity. The aim of the present work was to develop an appropriate kinetic model for PDH over a commercial Pt-Sn/γ-Al_2O_3 catalyst in the presence of small amounts of water. Experimental data were obtained from a previous study where catalytic PDH was carried out in a bench scale reactor system at atmospheric pressure in the temperature range of 575-620℃ in the presence of different amounts of water. The kinetics of the main dehydrogenation reaction were described in terms of a Langmuir-Hinshelwood rate expression and the effects of water on coke deposition and catalyst sintering were considered in a catalyst deactivation model to explain the observed optimum level in the amount of added water.