Dehydrogenation of dehydrogenatable hydrocarbons
AssigneeUop LLC
InventorTamotsu Imai
Life of this patent
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Abstract
Dehydrogenatable hydrocarbons may be subjected to a dehydrogenation reaction in which the hydrocarbons are treated with a dehydrogenation catalyst such as a modified iron compound in the presence of steam in a multi-catalyst bed system. The reaction mixture containing unconverted hydrocarbon, dehydrogenated hydrocarbon, hydrogen and steam is then contacted with a selective oxidation catalyst such as a noble metal of Group VIII of the Periodic Table, a metal of Group IVA of the Periodic Table and, if so desired, a metal of Group IA or IIA of the Periodic Table composited on a highly porous inorganic support. The oxidation catalyst will selectively oxidize the hydrogen to improve the combustion thereof and supply the necessary heat required for a subsequent dehydrogenation treatment.
Claims11
A process for the dehydrogenation of a dehydrogenatable hydrocarbon with separate and intermediate selective oxidation of hydrogen which compises:
- (a) contacting said hydrocarbon with a dehydrogenation catalyst comprising an alkaline metal-promoted iron compound in a first reaction-dehydrogenation zone in the presence of steam to produce a first reaction-dehydrogenation zone effluent stream comprising a mixture of uncoverted hydrocarbons, dehydrogenated hydrocarbons, hydrogen and steam;
- (b) removing said first-reaction dehydrogenation zone effluent from said first reaction-dehydrogenation zone;
- (c) passing said removed first-reaction dehydrogenation zone effluent of step (b) to a second-reaction oxidation zone, which is separate and discrete from said-reaction dehydrogenation zone;
- (d) contacting said first-reaction dehydrogenation zone effluent in said second-reaction oxidation zone with an oxygen-containing gas to selectively oxidize said hydrogen within said first-reaction dehydrogenation zone effluent to the substantial exclusion of oxidation of said unconverted and dehydrogenated hydrocarbons in the presence of an oxidation catalyst consisting essentially of about 0.01 to about 5 wt% of a Group VIII noble metal, about 0.01 to about 5wt% of a Group IVA metal, and from about 0.01 to about 10% by weight of a metal of Group IA or IIA composited on a highly porous alumina support at oxidation conditions, wherein said exothermic selective oxidation of said hydrogen provides additional heat and thereby raises the temperature of said unconverted and dehydrogenated hydrocarbons;
- (e) withdrawing said unconverted and dehydrogenated hydrocarbons from said second-reaction oxidation zone having an increased temperature with respect to the temperature of said first-reaction dehydrogenation effluent zone;
- (f) passing said removed second reaction-oxidation zone product stream of step (e) to a third-reaction dehydrogenation zone, containing a dehydrogenation catalyst comprising an alkaline metal promoted iron compound at dehydrogenation conditions to produce dehydrogenated hydrocarbons;
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- (g) withdrawing and recovering said dehydrogenated hydrocarbons.
Dependencies are inferred from the claim text.