Process for catalytically cracking hydrocarbons

Claim 1

IN A PROCESS FOR CRACKING HYDROCARBONS IN A FIXED CATALYTIC BED IN THE PRESENCE OF A CRACKING CATALYST WHICH GRADUALLY UNDERGOES LOSS OF ACTIVITY, AND THUS REQUIRES PERIODIC REPLACEMENT, AN IMPROVED METHOD FOR THE INSTALLATION AND REMOVAL OF THE CRACKING CATALYST WHICH COMPRISES DEPOSITING FROM A LIQUID MEDIA AN INITIALLY WET FILM OF CRACKING CATALYST UPON A PLURALITY OF CATALYTICALLY INACTIVE PORCELAIN SUPPORTS ARRANGED IN SPACED-APART RELATION WITH A REACTION CHAMBER, FLOWING A HOT GAS THROUGH SAID REACTION CHAMBER TO EFFECT DRYING OF SAID WET FILM OF CRACKING CATALYST UPON SAID SUPPORTS TO THERERBY LEAVE AN ADHERENT FILM OF ACTIVE CATALYST THEREON,ALTERNATELY FLOWING HYDROCARBONS UNDER CRACKING CONDITIONS, AND REGENERATING FLUID UNDER REGENERATING CONDITIONS, THROUGH SAID REACTION CHAMBER OVER SAID PORCELAIN SUPPORTS IN CONTACT WITH THE FILM OF CRACKING CATALYST DEPOSITED THEREON UNTIL THE ACTIVITY OF SAID CATALYST IS REDUCED BELOW A PREDETERMINED LIMIT, AND THEN, WITHOUT REMOVING SAID SUPPORTS FROM SAID REACTION CHAMBER, REMOVING THE RELATIVELY INACTIVE CATALYST FROM SAID PORCELAIN SUPPORTS BY MEANS OF A REAGENT WHICH IS CAPABLE OF ATTACKING SAID FILM OF CRACKING CATALYST BUT WHICH IS SUBSTANTIALLY INACTIVE WITH RESPECT TO SAID PORCELAIN SUPPORTS, AND THEN REDEPOSITING A NEW FILM OF ACTIVE CRACKING CATALYST UPON SAID SUPPORTS, THUS PREPARING SAID REACTION CHAMBER FOR FURTHER CRACKING OPERATIONS.