Patent ID: 7491860
Filing Date: 2009-02-17
Classification: B01J,C07C

Abstract:
1. A process for the dehydrogenation of aliphatic hydrocarbons, comprising (a) loading a first dehydrogenation catalyst in a first layer of a catalyst bed in a reactor; (b) loading a second dehydrogenation catalyst in a second layer of the catalyst bed in the reactor; (c) reducing the catalysts; and (d) introducing a feed stream to the catalyst bed, comprising an aliphatic hydrocarbon, such that the feed stream initially contacts the catalyst in the first catalyst layer and then the catalyst in the second catalyst layer, wherein the first catalyst comprises a catalyst with high activity but a higher capacity for producing coke than the catalyst of the second layer, and the second catalyst comprises a catalyst with the same or different activity, but a reduced capacity to make coke from the capacity of the catalyst of the first layer, wherein the composition of the catalysts of the first and second layers comprises from about 70 to about 90% by weight of alumina and from about 10 to about 30% by weight of one or more chromium compounds, and wherein the composition of the catalysts of the first layer contains a higher percentage of Cr +6 components, by weight, than the catalysts of the second layer.