| 摘要 |
579,477. Catalytic dehydrogenation. HOUDRY PROCESS CORPORATION. April 25, 1944, No. 7674. Convention date, March 5, 1943. Drawings to Specification. [Class 1 (i)] The catalytic dehydrogenation of hydrocarbons alternating with regeneration of catalyst in an adiabatic cycle is conducted at a temperature below that at which perfect adiabatic balance is attained, and the deficiency of heat is made up by supplying the reactant at a temperature higher than the average catalyst temperature. The temperature of adiabatic balance varies inversely as the contact time and the latter should be short enough to permit operation above 800 and preferably 900‹F. The usual catalysts may be employed, particularly chromium oxide on alumina, zirconia, or ceria. They may be pretreated with steam at 1200- 1600‹F. and a partial pressure between 1 and 30 lb. per sq in. According to an example, a catalyst comprising chromic acid on activated alumina is treated with steam at 1400‹F. and 3.25 lb. per sq. in. for ten hours and is then mixed with twice its volume of alundum. The mixture is used in a two stage process, the cycle comprising (1) dehydrogenation of butane. 5 minutes, (2) dehydrogenation of a mixture of butane and butene, 10 minutes, (3) regeneration, 10 minutes. Both reactants are supplied at 1100‹F., and the catalyst temperature attains equilibrium at 1080‹F. in the first stage and 1060‹F. in the second. The butadiene formed in the second stage is removed and the product of the first stage is used as make-up for the second. |
