Catalytic conversion of liquid hydrocarbons in the presence of suspended catalyst

Claim 1

IN A CONTINUOUS PROCESS FOR THE CATALYTIC CONVERSION OF HYDROCARBONS, WHEREIN THE HYDROCARBONS IN LIQUID PHASE ARE PASSED THROUGH A REACTION ZONE WITH PARTICLES OF SOLID CATALYST SUSPENDED IN SAID LIQUID TO FORM A SLURRY AND SAID HYDROCARBONS AND CATALYST ARE SUBJECTED TO HYDROCRACKING REACTION CONDITIONS IN SAID REACTION ZONE TO CONVERT SAID HYDROCARBONS, AT LEAST IN PART, TO LOWER BOILING PRODUCTS AND DEPOSIT CARBONACEOUS CONTAMINANTS ON THE CATALYST, THE IMPROVED METHOD FOR MAINTAINING SAID CATALYST IN AN ACTIVE CONDITION WHICH COMPRISES: SEPARATING VAPOR FROM THE EFFLUENT OF SAID REACTION ZONE AND PASSING THE REMAINING LIQUID AND SOLID CATALYST TO A LIQUID SEPARATION ZONE; WITHDRAWING LIQUID FROM THE UPPER SECTION OF SAID LIQUID SEPARATION ZONE WHILE CATALYST PARTICLES SETTLE TO THE BOTTOM THEREOF, THE UPWARD VELOCTY OF LIQUID IN SAID LIQUID SEPARATION ZONE BEING INSUFFICIENT TO SUSPEND CATALYST PARTICLES OF A SIZE SUITABLE TO BE RETAINED IN THE CYCLIC SYSTEM: PASSING THE SOLID CATALYST INTO A SOLIDS SEPARATION ZONE AND FLOWING AT LEAST A PORTION OF THE HYDROCARBONS TO BE CHARGED TO THE REACTION ZONE UPWARDLY THROUGH SAID SOLIDS SEPARATION ZONE AT A VELOCITY WHICH IS INSUFFICIENT TO SUSPEND THE HEAVIER CATALYST PARTICLES BEARING THE HIGHER QUANTITIES OF CARBONACEOUS CONTAMINANTS BUT IS SUFFICIENT TO SUSPEND THE LIGHTER CATALYST PARTICLES WHICH BEAR LOWER AMOUNTS OF CARBONACEOUS CONTAMINANTS; PASSING THE HYDROCARBON CHARGE CARRYING THE ATALYST WITH LOWER AMOUNTS OF CARBONACEOUS CONTAMINANTS INTO THE REACTION ZONE TO BE CONVERTED; PASSING THE CATALYST WITH HIGHER MOUNTS OF CARBONACEOUS CONTAMIINANTS THEREIN AND RETURNING CATALYST WITH CONTAMINANTS REMOVED FROM THE REGENERATION ZONE TO THE REACTION ZONE.