jahnig

Claim 1

IN A PROCESS FOR THE CONVERSION OF HYDROCARBONS IN CONTACT WITH FINELY DIVIDED CATALYST SOLIDS WHEREIN SAID CATALYST SOLIDS ARE CONTINUOUSLY CIRCULATED FROM A HYDROCARBON CONVERSION ZONE TO A SEPARATE REGENERATION ZONE WHERE INACTIVATING CARBONACEOUS DEPOSITS ARE BURNED FROM THE CATALYTIC SOLIDS AND THENCE BACK TO THE CONVERSION ZONE, AND WHEREIN AN OXYGEN-CONTAINING REGENERATION GAS IS SUPPLIED TO THE REGENERATION ZONE AT A SUFFICIENT RATE TO MAINTAIN THE FINELY DIVIDED CATALYTIC SOLIDS THEREIN AS A DENSE FLUIDIZED BED, THE IMPROVEMENT WHICH COMPRISES WITHDRAWING HOT CATALYTIC SOLIDS FROM SAID DENSE FLUIDIZED BED OF THE REGENERATION ZONE, MAINTAINING THE WITHDRAWN CATALYTIC SOLIDS AS AN AUXILIARY DENSE FLUIDIZED BED HAVING AN UPPER LEVEL AND A DISPERSE PHASE THEREABOVE IN A HEAT EXCHANGE ZONE HAVING A RELATIVELY SMALL HORIZONTAL CROSS SECTION IN COMPARISON WITH THE HORIZONTAL CROSS SECTION OF THE DENSE FLUIDIZED BED IN TTHE REGENERATION ZONE, MAINTAINING A COOL HEAT EXCHANGE FLUID IN INDIRECT HEAT EXCHANGE RELATION WITH THE WITHDRAWN CATALYTIC SOLIDS ALONG A HEAT EXCHANGE SURFACE EXTENDING FROM THE AUXILIARY DENSE FLUIDIZED BED INTO THE DISPERSE PHASE THEREABOVE, THEREBY COOLING THE SAID CATALYST SOLIDS, WITHDRAWING COOLED CATALYTIC SOLIDS DOWNWARDLY FROM THE AUXILIARY DENSE FLUIDIZED BED, MIXING THE WITHDRAWN COOLED CATALYTIC SOLIDS WITH OCYGEN-CONTAINING REGENERATION GAS, AND PASSING THE RESULTANT MIXTURE INTO SAID REGENERATION ZONE, AND REGULATING THE RATE AT WHICH THE CATALYTIC SOLIDS ARE SUPPLIED TO AND WITHDRAWN FROM THE AUXILIARY DENSE FLUIDIZED BED IN ORDER TO CONTROL THE POSITION OF THE UPPER LEVEL OF THE SAID AUXILIARY DENSE FLUIDIZED BED IN CONTACT WITH THE HEAT EXCHANGE SURFACE AND THEREBY CONTROL THE PROPORTION OF THE HEAT EXCHANGE SURFACE IMMERSED IN THE AUXILIARY DENSE FLUIDIZED BED.