GB593989A - Improvements in or relating to vapor phase isomerization processes - Google Patents

Abstract

In the isomerization of paraffins by passage in the presence of hydrogen halide over a heated catalyst bed comprising a metal halide absorbed on a porous support, metal halide vapours are added to one portion of the catalyst bed to reactivate it while the supply of hydrogen halide thereto is discontinued, while isomerization is continued in another portion of the bed wherein the metal halide vapours are in equilibrium with the halide absorbed on the support. A paraffin such as n-butane is heated and fed by line 15 to a vessel 16 containing aluminium chloride which is sublimed and carried by the stream via line 18 to reactor 19 where it is deposited on an absorbent 20 such as bauxite or "Porocel" (Registered Trade Mark). When the absorbent becomes saturated, vessel 16 is bye-passed and hydrogen chloride introduced into line 18 by line 25 and valve 24, isomerization of the paraffin then proceeding. When the bed 20 requires regeneration, the paraffin feed is passed through vessel 16 again, and valve 24 is closed to withhold hydrogen chloride from the lower part of bed 20. Valve 27 is at the same time opened to supply <PICT:0593989/III/1> hydrogen chloride to the upper part of the bed through pipe 29 and jets 30. The temperature of the paraffin feed may be increased to compensate for the smaller volume of catalyst bed used in isomerization. The amount of aluminium chloride added during reactivation should not exceed 5 per cent. by weight of the total absorbent to avoid fouling of the upper part of the bed. In an example, temperature is raised from 270-300 DEG F. during a 10 day operation, with 4-7 per cent. addition of promoter based on the weight of hydrocarbon. Reactivation is effected by adding 2-3 per cent. of aluminium chloride by line 18 while the upper part of the bed is isomerizing at about 290-300 DEG F. The different sections of the bed may consist of a number of separate vessels in series.ALSO:<PICT:0593989/IV/1> In the isomerization of paraffins by passage in the presence of hydrogen halide over a heated catalyst bed comprising a metal halide adsorbed on a porous support, metal halide vapours are added to one portion of the catalyst bed to reactivate it while the supply of hydrogen halide thereto is discontinued, while isomerization is continued in another portion of the bed wherein the metal halide vapours are in equilibrium with the halide adsorbed on the support. A paraffin such as n-butane is heated and fed by line 15 to a vessel 16 containing aluminium chloride which is sublimed and carried by the stream via line 18 to reactor 19 where it is deposited on an adsorbent 20 such as bauxite or "Porocel" (Registered Trade Mark). When the adsorbent becomes saturated, vessel 16 is byepassed and hydrogen chloride introduced into line 18 by line 25 and valve 24, isomerization of the paraffin then proceeding. When the bed 20 requires regeneration, the paraffin feed is passed through vessel 16 again, and valve 24 is closed to withhold hydrogen chloride from the lower part of bed 20. Valve 27 is at the same time opened to supply hydrogen chloride to the upper part of the base through pipe 29 and jets 30. The temperature of the paraffin feed may be increased to compensate for the smaller volume of catalyst bed used in isomerization. The amount of aluminium chloride added during reactivation should not exceed 5 per cent by weight of the total adsorbent to avoid fouling of the upper part of the bed. In an example, temperature is raised from 270-300 DEG F. during a 10-day operation, with 4-7 per cent addition of promoter based on the weight of hydrocarbon. Reactivation is effected by adding 2-3 per cent of aluminium chloride by line 18 while the upper part of the bed is isomerizing at about 290-300 DEG F. The different sections of the bed may consist of a number of separate vessels in series.