초록 ▼

Dehydrogenatable hydrocarbons may be subjected to a dehydrogenation reaction in which the hydrocarbons are treated with a dehydrogenation catalyst comprising a modified iron compound in the presence of steam in a multicatalyst bed system. The reaction mixture containing unconverted hydrocarbons, deh

Dehydrogenatable hydrocarbons may be subjected to a dehydrogenation reaction in which the hydrocarbons are treated with a dehydrogenation catalyst comprising a modified iron compound in the presence of steam in a multicatalyst bed system. The reaction mixture containing unconverted hydrocarbons, dehydrogenated hydrocarbons, hydrogen and steam is then contacted with an oxidation catalyst whereby hydrogen is selectively oxidized in preference to carbon dioxide and carbon monoxide or hydrocarbons. The selective oxidation of hydrogen will improve the combustion thereof and supply the necessary heat which is required for a subsequent dehydrogenation treatment. The selective oxidation catalyst which is used will comprise a noble metal of Group VIII of the Periodic Table and, if so desired, a metal of Group IA or IIA of the Periodic Table composited on a porous inorganic support. The inorganic support will have been calcined prior to impregnation thereof at a temperature in the range of from about 900°to about 1500°C. in the absense or presence of steam to provide a catalyst which possesses increased stability and activity when compared to prior catalysts.

대표청구항 ▼

In a process for the dehydrogenation of dehydrogenatable hydrocarbon with separate and intermediate selective oxidation of hydrogen which comprises: (a) contacting said hydrocarbon with a dehydrogenation catalyst comprising an alkaline metal-promoted iron compound in a first-reaction dehydrogenation

In a process for the dehydrogenation of dehydrogenatable hydrocarbon with separate and intermediate selective oxidation of hydrogen which comprises: (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 at dehydrogenation conditions to produce a first-reaction dehydrogenation zone effluent stream comprising a mixture of unconverted 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 first-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 zone effluent to the substantial exclusion of oxidation of said unconverted and dehydrogenated hydrocarbons in the presence of an oxidation catalyst consisting essentially of a Group VIII noble metal, a Group IVA metal, and a Group IA or IIA metal composited on an 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 zone effluent; (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; and (g) withdrawing and recovering said dehydrogenated hydrocarbons, the improvement which comprises calcining said alumina support of said oxidation catalyst used in step (d) at a temperature in the range of from about 900°to about 1500°C. prior to impregnation thereon of all of the metallic portions of said oxidation catalyst.