GB779380A - Improvements in or relating to dehydrogenation process - Google Patents

Abstract

<PICT:0779380/IV(b)/1> In the catalytic dehydrogenation of a hydrocarbon feed to produce a more unsaturated compound a dehydrogenation catalyst is suspended in a vapour stream of the hydrocarbon for a uniformly short period of time of not more than 1 second under sub-atmospheric pressure in a transfer line reaction zone, the spent catalyst being continuously withdrawn from the system, regenerated and returned hot to the reaction zone. The process may be applied to the dehydrogenation of (a) butane to butylene and butadiene, (b) butylene to butadiene, (c) isobutane to isobutylene, (d) ethyl benzene to styrene, (e) isopentane to trimethylethylene, (f) trimethylethylene to isoprene, (g) isopentane to isoprene and (h) paraffins and isoparaffins in the naphtha boiling range to the corresponding olefins and diolefins. The catalyst may be nickel or alumina, or compositions of alumina with chromium, tungsten or molybdenum, or with metallic oxides such as those of copper, cobalt and nickel; a preferred catalyst is one consisting of a major portion of magnesium oxide, a minor portion of iron oxide, a promoter such as potassium carbonate, and a stabilizer such as CuO. The catalyst regeneration vessel may be of the dense fluid bed type or of the transfer line type. In a preferred embodiment shown in Fig. 2 in which n butane is dehydrogenated to butadiene the reaction takes place in a vessel 112 located in a housing 113, the reactant gases passing in through feed line 102 while the heated regenerated catalyst is passed upwardly through duct 114. The spent catalyst is disengaged abruptly from the vaporous product stream into a number of cyclone separators 110 with entrance ducts at or near the top of the reactor. The catalyst then passes through duct 134 and into burner vessel 118 in which the catalyst is treated with air from line 136 to regenerate and heat it to a temperature of the order of 1150-1450 DEG F.ALSO:<PICT:0779380/III/1> In the catalytic dehydrogenation of a hydrocarbon feed to produce a more unsaturated compound a dehydrogenation catalyst is suspended in a vapour stream of the hydrocarbon for a uniformly short period of time of not more than 1 second under sub-atmospheric pressure in a transfer line reaction zone, the spent catalyst being continuously withdrawn from the system, regenerated, and returned hot to the reaction zone. The process may be applied to the dehydrogenation of (a) butane to butylene and butadiene, (b) butylene to butadiene, (c) isobutane to isobutylene, (d) ethyl benzene to styrene, (e) isopentane to trimethylethylene, (f) trimethylethylene to isoprene, (g) isopentane to isoprene and (h) paraffins and isoparaffins in the naphtha boiling range to the corresonding olefins and diolefins. The catalyst may be nickel or alumina or compositions of alumina with chromium, tungsten or molybdenum, or with metallic oxides such as those of copper, cobalt and nickel; a preferred catalyst is one consisting of a major portion of magnesium oxide, a minor portion of iron oxide, a promoter such as potassium carbonate, and a stabilizer such as CuO. The catalyst regeneration vessel may be of the dense fluid bed type or of the transfer line type. In a preferred embodiment shown in Fig. 2 in which n. butane is dehydrogenated to butadiene the reaction takes place in a vessel 112 located in a housing 113, the reactant gases passing in through feed line 102 while the heated regenerated catalyst is passed upwardly through duct 114. The spent catalyst is disengaged abruptly from the vaporous product stream into a number of cyclone separators 110 with entrance ducts at or near the top of the reactor. The catalyst then passes through duct 134 and into burner vessel 118 in which the catalyst is treated with air from line 136 to regenerate and heat it to a temperature of the order of 1150 DEG -1450 DEG F.