Patent ID: 8063261

Claim:
A catalyst system for dehydrogenating an alkane hydrocarbon feed stream and having improved selectivity and yield, the catalyst system comprising: a first catalyst comprising about 50 to about 90 percent by weight of an eta alumina carrier, about 10 to about 50 percent by weight of a chromium compound, and about 0.1 to about 5 percent by weight of a zirconium compound, wherein the chromium compound and the zirconium compound are impregnated on the eta alumina and the zirconium compound functions to stabilize the chromium compound; and a second catalyst comprising about 50 to about 90 percent by weight of eta alumina carrier and about 10 to about 50 percent by weight of a chromium compound, and wherein the second catalyst does not include a zirconium compound; wherein a plurality of the first catalyst forms a first catalyst layer of the catalyst system and a plurality of the second catalyst forms a second catalyst layer of the catalyst system that is downstream of the first catalyst layer relative to the flow of the feed stream over the first and second catalyst layers such that the hydrocarbon feed stream first contacts the first catalyst layer and then contacts the second catalyst layer to produce a dehydrogenated unsaturated alkene or alkadiene hydrocarbon product, and the first catalyst layer comprises about 5 to about 90 weight percent of the catalyst system.