A two-phase model, which takes into account the change of the number of moles associated with the reaction, is used to investigate the possibility of using fluidized bed configurations without and with selective metallic (or composite) membranes to conduct the catalytic reversible endothermic reaction for the dehydrogenation of ethylbenzene to styrene. This reaction is usually carried out industrially in adiabatic fixed beds. The effect of different design and operating parameters for the two fluidized bed configurations is investigated and the results are compared with those of an equivalent industrial fixed bed unit. It is shown that through the proper choice of design and operating parameters a considerable increase in the styrene production, over that of the industrial fixed bed unit, can be achieved.