Process for the catalytic conversion of hydrocarbons and the stripping of the fouledcatalyst particles with steam

Claim 1

IN THE FLUID CATALYST PROCESS FOR THE CONVERSION OF HYDROCARBONS WHEREIN DENSE PHASE BODIES OF THE FLUIDIZED CATALYST ARE MAINTAINED IN A REACTION ZONE AND IN A REGENERATING ZONE, RESPECTIVELY, THE CATALYST IN CONTINUOUSLY REGENERATED IN THE REGENERATING ZONE BY CONTACT WITH AIR UNDER CONDITIONS ADAPTED TO AVOID EXCESSIVE RISE IN TEMPERATURE, REGENERATED CATALYST IS WITHDRAWN FROM THE BODY OF THE CATALYST IN THE REGENERATING ZONE, SUSPENDED IN OIL VAPORS AND CONVEYED THEREBY TO THE REACTION ZONE, CATALYST IS CONTINUOUSLY WITHDRAWN FROM THE BODY OF CATALYST IN THE REACTION ZONE, STRIPPED OF OIL IN A STRIPPING ZONE BY CONTACT WITH A STEAM STRIPPING MEDIUM AND RETURNED TO A BODY OF CATALYST IN THE REGENERATING ZONE, THE IMPROVEMENT WHICH COMPRISES WITHDRAWING CATALYST BY GRAVITY FROM A LOWER PORTION OF THE BODY OF CATALYST IN THE REACTION ZONE, SUSPENDING THE WITHDRAWN, SUBSTANTIALLY UNSTRIPPED CATALYST IN A STEAM STREAM AND CONVEYING IT THEREBY UPWARDLY TO THE LOWER PORTION OF A STRIPPING ZONE SEPARATE FROM THE REACTION ZONE, POSITIONED AT AN ELEVATION SUCH THAT THE BODY OF CATALYST THEREIN EXTENDS TO AN ELEVATION HIGHER THAN THE UPPER SURFACE OF THE BODY OF CATALYST IN THE REGENERATING ZONE AND IS IN A RELATIVELY DENSE PHASE AND FROM WHICH THE PASSING OF STRIPPING STEAM TO THE REACTION ZONE IS PREVENTED, STRIPPING THE CATALYST IN THE STRIPPING ZONE BY PASSING THE STEAM CONVEYING MEDIUM UPWARDLY THROUGH THE DENSE PHASE CATALYST IN THIS ZONE, PASSING THE STRIPPED CATALYST BY GRAVITY FROM THE STRIPPING ZONE TO THE UPPER PORTION OF THE DENSE PHASE BODY OF CATALYST IN THE REGENERATING ZONE, INTRODUCING STEAM INTO THE CATALYST AS IT PASSES FROM THE STRIPPING ZONE TO THE REGENERATING ZONE TO EFFECT A SEAL FOR PREVENTING REGENERATION GASES FROM PASSING INTO THE STRIPPING ZONE, AND PASSING REGENERATION AIR UPWARDLY THROUGH THE BODY OF CATALYST IN THE REGENERATING ZONE, WHEREBY SUBSTANTIAL BURNING OF THE CARBONACEOUS DEPOSIT FROM THE CATALYST IN TRANSIT FROM THE REACTION ZONE TO THE ZONE OF REGENERATION IS AVOIDED.