Multiple-level tcc catalyst stripping

Claim 1

IN A PROCESS OF HYDROCARBON CONVERSION WHEREIN A MOVING BED OF CATALYST IS WITHDRAWN FROM THE REACTION ZONE AS A PLURALITY OF COMPACT FIRST COLUMNS OF DOWNWARDLY MOVING CONTIGUOUS CATALYST PARTICLES, AN INERT PURGE GAS IS ADMIXED TO THE BASE OF EACH OF SAID FIRST COLUMNS AND WITHDRAWN FROM THE SURFACES THEREOF, AND SAID FIRST COLUMNS ARE THEN COMBINED INTO A SINGLE MOVING COLUMN OF CONTIGUOUS PARTICLES, AND WHEREIN BLOCKING OF CATALYST FLOW TO ONE OR MORE OF SAID FIRST COLUMN BEING STRIPPED BY SAID PURGE GAS RESULTS IN THE EVACUATION OF THE COLUMNS THUS AFFECTED AND A RESULTANT CHANNELING OF SAID PURGE GAS THROUGH THE RESULTING VOID, THE IMPROVEMENT COMPRISING INJECTING ADDITIONAL INERT PURGE GAS INTO THE LOWER PORTION OF SAID SINGLE COLUMN OF CATALYST, FORCING SAID ADDITIONAL PURGE GAS THROUGH SAID SINGLE COLUMN AND ALSO THROUGH THE AFORESAID PLURALITY OF COLUMNS, AND WITHDRAWING SAID ADDITIONAL PURGE GAS AT AT THE SURFACE OF SAID FIRST COLUMNS ALONG WITH THE PURGE GAS INITIALLY ADMITTED THERETO.