GB568298A - Process for effecting endothermic reactions of hydrocarbons in the presence of catalysts - Google Patents

Abstract

568,298. Cracking oils ; dehydrogenating butane. UNIVERSAL OIL PRODUCTS CO. Jan. 6, 1943, No. 265. Convention date, Dec. 8, 1941. [Classes 1 (i) and 32] In processes for the catalytic conversion of hydrocarbons, e.g. cracking, dehydrogenation, &c., of the kind in which the hydrocarbons are reacted in suspension with the catalysts which are thereafter separated and regenerated with an oxygen containing gas and returned to the conversion zone, additional combustible material is supplied to the regeneration zone so that the catalyst is heated to such a degree that the amount of heat units contained therein are sufficient for effecting the endothermic conversion reaction without supplying external heat thereto. The apparatus comprises an endothermic reactor 3 with superposed regenerator 24. Hydrocarbon vapours are supplied through line 1 and are mixed with catalyst issuing from a pipe 39 through opening 42. The suspension passes upwardly through a perforated distributing plate 4 supporting a relatively dense mass of catalysts. Reacted vapours pass through conduit 7 and a series of separators 6, 10 where catalyst carried off by the vapours is separated and returned through lines 8, 11 to below the surface of the catalyst bed, the vapours passing through line 12 to the usual fractionating and recovery plant. The catalyst is transferred continuously through conduit 15 where it is stripped from residual vapours by steam or process gases admitted through line 16. The catalyst then flows down tube 21 and is admixed with regenerating gases fed through line 22, the injector action of the gases transferring the catalyst through line 47 to the regenerator 24, the regenerated catalyst being returned to the reactor through the pipe 39. The used gases pass off through line 27 and are separated from catalyst in separator 26 and then flow off through line 30 and coil 44 in heat exchanger 32 where the residual heat of the gases is used to preheat air admitted through line 33 ; the preheated air then flows through line 35 to line 37 where it is admixed with extraneous fuel, e.g. in liquid, solid or gaseous state admitted through line 50, this fuel being burnt in the regenerator 24 and serving to supply the extra heat units required by the catalyst for the endothermic reaction. The process is described with reference to the conversion of butane to butenes by heating normal butane to 580‹ C. and passing it through a reactor in contact with catalyst heated to 640‹ C. and comprising a mixture of chromium oxide and alumina. The catalyst being regenerated is raised to the required temperature by admixture with further air preheated to 400‹ C. and mixed with coke equivalent in amount to 1.2 kg. per kg. mol. of butane. Specification 547,130 is referred to.