A rigorous heterogeneous model was used to extract intrinsic kinetic parameters for the catalytic dehydrogenation of ethylbenzene to styrene on different promoted iron oxide catalysts. A pseudohomogeneous model was used to extract intrinsic kinetics for three in-house prepared catalysts. The extracted intrinsic kinetics were used in a heterogeneous fixed bed model based on the dusty gas model (Stefan-Maxwell equations) to simulate the industrial reactor. A two-phase model, which takes into account the change of the number of moles associated with the reaction, was used to investigate the possibility of using fluidized configurations to conduct this dehydrogenation reaction. The two models were then used to investigate the advantages of using selective membranes for the removal of the produced hydrogen from reaction mixture. It was found that maximization of styrene yield is possible through the proper design and selection of reactor configurations, catalysts and operating conditions.
The maximization of the product yield from a catalytic reactor for the production of styrene from ethylbenzene, involve many chemical reactions engineering research interests in an integrated and interactive fashion. Such an undertaken will include the semi-empirical art of catalyst design which is slowly enveloping into a very interesting science aiming at designing the best catalyst which gives the highest yield of the desired product and the lowest yield of the undesired products under conditions of high reactivity. The art of catalyst design in other words concentrates on the intrinsic kinetics of the catalyst behavior that is free of diffusional limitations. This diffusional resistances effect the different intrinsic rates of reaction in different magnitudes thus affecting the conversions, yields and selectivities in complex manner. Such intra-particle diffusional resistance can be eliminated by the use of powdered catalysts in fluidized beds. * Author to whom all correspondence should be addressed. Fax (+ 605)3132944, E-Mail: ([email protected]).
The main dehydrogenation reaction of the ethylbenzene to styrene is a reversible reaction which is limited by the thermodynamic equilibrium of this reaction regardless of the intrinsic catalyst activity, the
