Int. J. Hydrogen Energy, Vol. 16, No. 1, pp. 55-60, 1991. Printed in Great Britain. 0360-3199/91 $3.00+ 0.00 Pergamon Press plc. © 1990InternationalAssociation for Hydrogen Energy. DEHYDROGENATION OF METHYLCYCLOHEXANE IN A REACTOR COUPLED TO A HYDROGEN ENGINE D. KLVANA,* A. TOUZANI,* J. CHAOUKI* and G. Bf~LANGER~ *Department of Chemical Engineering, Ecole Polytechnique, P.O. Box 6079, Station A, QC, Canada, H3C 3A7, tRecherche et Essais-Mat6riaux, IREQ, 1800 Mont6e Ste-Julie, QC, Canada J0L 2PO (Received for publication 8 August 1990) Abstract--The simulation study of the dehydrogenation of methylcyclohexane (MCH) in an on-board reactor has shown that an amount of hydrogen sufficient for a propulsion of a six-cylinder vehicle may be liberated from methylcyclohexane when a Pt-Sn/A1203 industrial catalyst is used. This results has been supported experimentally by using a pilot unit which simulates the coupling of the hydrogen engine to the dehydrogenation reactor. Thus, the use of methylcyclohexane as a hydrogen cartier for vehicles equipped with hydrogen engine is potentially feasible. C Cp D DR DR d~ H L P Per P'er R r rw T U 2 Greek Oiw AI-I E )'R P. P NOMENCLATURE concentration, mol m- 3 specific heat, J kg-l K-I cylinder diameter, m reactor diameter, m radial diffusivity, m2 s-t particle diameter, m cylinder height, m length of the catalytic bed, m pressure, Pa (0.987 x 10-5 atm) radial Peclet number for mass transfer (u dp D~ t E -l) radial Peclet number for heat transfer (u dp p Cp 2~ 1E -1) radius of reactor, m radial distance, m rate of reaction,/~mol s -1 kgg,~ temperature, K superficial velocity of fluid, m s-1 axial distance, m letters wall heat transfer coefficient, J m -2 s -1 °C -1 total heat of reaction, J mol-t void fraction effective radial thermal conductivity, J m -1 s -1 °C i bulk density of catalyst, kg m -a density, kg m -3 Subscripts o inlet of the catalytic bed H hydrogen T toluene w wall i internal e external INTRODUCTION The use of hydrogen as a fuel for automotive power in transportation vehicles with an internal combustion engine has been studied for several years [1, 2]. In Quebec (Canada), where hydroelectricity is abundant, this clean fuel would be especially suitable. Among the variety of hydrogen storage systems, cycloparaffins are very attractive to serve as hydrogen carriers. The feasibility of the use of cycloparaffins has been studied by several research groups (Taube et al. [3], Cacciola et al. [4], Touzani et al. [5]). In our laboratories the long term objective is to develop a demonstration pilot unit in which the hydro- gen engine is directly coupled to the dehydrogenation reactor. To attain this objective, a complete kinetic study of the dehydrogenation of methylcyclohexane (MCH) over an industrial Pt-Sn/AI20 3 catalyst was first per- formed by Touzani et al. [6]. Then by using the results of the kinetic study, and a series of experimental data, a model for a tubular reactor was derived [7]. Although very encouraging results have been obtained with the above Pt-Sn/A1203 industrial catalyst, it has been found that to maintain the catalyst activity, the reaction must be carried out under a minimum hydrogen pressure. Therefore, in an effort to alleviate the functional nature of the catalyst and to reduce cracking and isomerization, the industrial catalyst was modified. As shown by Chaouki et al. [8], the modified catalyst is five times more resistant to deactivation than the old one. A new kinetic model for the modified catalyst was derived, based on the same mechanism as for the previous catalyst. In this paper, we present the results of a simulation study and the data obtained on the laboratory exper- imental dehydrogenation unit simulating the hydrogen engine coupled reactor. These data, i.e. the amount of a converted MCH, are compared with a target value of 16.25 x 10 -2 mol s -1 based on the fuel requirement for a six-cylinder vehicle (consumption of 11 1 of gasoline per 100 km). 55