GB602471A - Improved hydrocarbon conversion process - Google Patents

Abstract

<PICT:0602471/III/1> In a hydrocarbon conversion process, e.g. catalytic cracking, in which hydrocarbon vapours are contacted in a reaction zone 10 with a fluidised mass of contact particles which are regenerated by burning in a zone 108, the fouled particles from the reaction zone are passed to a separate stripping zone 68 which is maintained at a higher temperature than the reaction zone by the passage thereto of hot regenerated contact particles from the regeneration zone. Contact particles, after a preliminary stripping in annular zone 44, leave the reactor through line 56, mix with regenerated material from line 72 and pass through line 66 to the stripper; stripping gas, such as steam, flue gases, nitrogen, or carbon dioxide, is introduced at 78. The remainder of the regenerated material passes through line 16 and mixes with the feed introduced at 14. Stripped particles from the zone 68 are mixed with regeneration gas led in at 116 and flow through line 114 to the regenerator 108. The stripping gases leave at 94 and may be mixed with the reaction products either above the dense phase in the reactor or in line 38, or may be separately treated to recover hydrocarbons and catalyst. An oxygen-containing gas, such as air, may be introduced into the stripping zone to increase the temperature therein. Grids, baffles, or perforated partitions may be provided in the stripper. The temperatures in a cracking process may be 800 DEG -950 DEG F. in the reactor, 900 DEG -1000 DEG F. in the stripper, and 950 DEG -1100 DEG F. in the regenerator. The temperature in the regenerator may be controlled by a cooling coil immersed in the dense bed, or by passing part of the contact material through a cooler and back to the vessel. The process is also applicable (Fig. 2, not shown) in conversions where the contact material is carried upwardly by the vapours out of the various zones and separated in cyclone separators. Contact particles separated from the reaction products are maintained in the fluidised state in a hopper into which hot regenerated contact material may be led. Part of the stripped contact material may be passed back to the reactor.