EXPERIMENTAL STUDIES OF THE NONOXIDATIVE DEHYDROGENATION OF ETHYLBENZENE USING A MEMBRANE REACTOR

The non-oxidative dehydrogenation of ethylbenzene to styrene has been studied in membrane reactors consisting of two concentric tubes. The inner tube is packed with particles of Shell 105 catalyst. This tube is an ALCOA alumina membrane characterized by a mean pore diameter of 50 angstrom. The feed to the inner tube consists of ethylbenzene, water and nitrogen. A sweep stream of nitrogen flows through the annulus in cocurrent fashion. Two membrane reactors were employed. The first was operated at 555-degrees-C and the second at 602-degrees-C. During the first 25 to 35 h of operation, equilibrium was achieved with respect to transport of hydrogen, water and nitrogen across the membrane. Subsequently, the amount of material transferred across the membrane steadily decreased. Inspection of used membranes indicated that carbon deposition was causing significant clogging of the membrane.