Patent ID: 7271307

Claim:
In a standard Houdry process for the dehydrogenation of aliphatic hydrocarbons wherein the process defines a cycle that includes the stages of: (a) loading a dehydrogenation catalyst into a reactor to form a catalyst bed wherein the bed defines a top section, a middle section and a bottom section; (b) evacuating the catalyst bed; (c) reducing the catalyst bed with hydrogen and evacuating the bed; (d) introducing an aliphatic hydrocarbon into the catalyst bed as a gas feed at a preselected flow rate and such that the feed initially contacts the top section of the bed and exits after contact with the bottom section and after the hydrocarbon is dehydrogenated; (e) steam purging and regenerating the catalyst bed; (f) repeating stages (b) through (e); and wherein the length of stages (b) through (e) are controlled by a sequencer, the improvement of (1) extending the cycle length by the introduction of a delay of at least one predetermined time interval into at least one stage of the cycle; and (2) introducing hydrogen gas, at concentration of up to about 7 mol % H 2 , into the reaction at stage (d).