%0 Journal Article
%T Dehydrogenation of Methylcyclohexane: Parametric Sensitivity of the Power Law Kinetics
%A Muhammad R. Usman
%A David L. Cresswell
%A Arthur A. Garforth
%J ISRN Chemical Engineering
%D 2013
%R 10.1155/2013/152893
%X For heterogeneous catalytic reactions, the empirical power law model is a valuable tool that explains variation in the kinetic behavior with changes in operating conditions, and therefore aids in the development of an appropriate and robust kinetic model. In the present work, experiments are performed on 1.0£¿wt% Pt/Al2O3 catalyst over a wide range of experimental conditions and parametric sensitivity of the power law model to the kinetics of the dehydrogenation of methylcyclohexane is studied. Power law parameters such as order of the reaction, activation energy, and kinetic rate constants are found dependent upon the operating conditions. With H2 in the feed, both apparent order of the reaction and apparent activation energy generally increase with an increase in pressure. The results suggest a kinetic model, which involves nonlinear dependence of rate on the partial pressure of hydrogen and adsorption kinetics of toluene or some intermediate. 1. Introduction Dehydrogenation of a cycloalkane such as methylcyclohexane (MCH) is an important model reaction in reforming of naphtha [1]. A typical reformer feedstock has 20¨C60£¿vol% naphthenes [2], which principally undergo dehydrogenation to aromatics. The dehydrogenation of MCH is an essential reaction in the methylcyclohexane-toluene-hydrogen (MTH) system for the safe and economical storage and utilization of hydrogen [3]. Moreover, it can be a valuable model reaction in the refining of naphthenic-based heavy crude oils [4]. For heterogeneous catalytic reactions, the empirical power law model is an important tool in providing the variation in the kinetic behavior to elaborate the insight of the kinetics of a reaction and therefore helps in guiding towards the development of an appropriate and robust kinetic model. Kinetics of the MCH dehydrogenation over supported Pt catalysts has been studied by a number of researchers [1, 4¨C21]. However, the variation in kinetic behavior and kinetic parameters (power law index, rate constant, and activation energy) of the dehydrogenation reaction with variation in operating conditions is rarely studied [19, 22]. Both Jossens and Petersen [22] and Alhumaidan et al. [19] carried out experiments in the presence of hydrogen and analyzed the data with initial rate method. The present study, on the other hand, is designed to conduct a more rigorous and comprehensive kinetic investigation including experiments without hydrogen in the feed over 1.0£¿wt% Pt/¦Ã-Al2O3 catalyst. Based on the power law model, kinetic analysis is carried out in which the effect of the operating
%U http://www.hindawi.com/journals/isrn.chemical.engineering/2013/152893/