Hydrocarbon conversion process

Claim 1

A PROCESS FOR CONVERTING, IN THE PRESENCE OF A SOLID POROUS CRACKING CATALYST, A HYDROCARBON OIL CONTAINING A METAL CONTAMINANT SELECTED FROM THE GROUP CONSISTING OF NICKEL, COPPER AND VANADIUM THAT TENDS TO DEPOSIT ON THE SURFACE OF SAID CATALYST WITH CONCOMITANT UNDESIRABLE EFFECT ON ITS CRACKING ACTIVITY WHICH COMPRISES CONTACTING SAID OIL UNDER CATALYTIC CRACKING CONDITIONS WITH A MOVING COMPACT BED OF PARTICLE-FORM SOLID CONTACT MATERIAL CONSISTING OF A MIXTURE OF TWO SPECIES OF PARTICLES, ONE OF WHICH, PRESENT IN MINOR AMOUNT AND HAVING ADSORBENT PROPERTIES, IS PREFERENTIALLY SEGREGATED SO AS TO MAKE INITIAL CONTACT WITH SAID OIL AND ADSORB A MAJOR PROPORTION OF SAID METAL CONTAMINANT THEREFROM BEFORE THE OIL COMES INTO CONTACT WITH THE SECOND SPECIES OF PARTICLES PRESENT IN MAJOR AMOUNT AND COMPRISING A CRACKING CATALYST DIFFERING IN PARTICLE SIZE AND HAVING A HARDNESS GREATER THAN THAT OF THE FIRST PARTICLE SPECIES WHEREBY, AS A RESULT OF MUTUAL GRINDING DURING MOVEMENT OF THE PARTICLES COMPRISING SAID COMPACT BED ATTRITION PREFERENTIALLY ABRADES THE METAL-BEARING SURFACES OF PARTICLES OF THE FIRST SPECIES CONTROLLING THE RESIDENCE TIME BETWEEN THE OIL CHARGE AND FIRST PARTICLE SPECIES SO THAT THE AMOUNT OF METAL CONTAMINANT ACCUMULATING ON THE SURFACE OF SAID SPECIES DOES NOT EXCEED ABOUT 100 P.P.M. BASED ON WEIGHT OF SAID SECOND PARTICLE SPECIES, CONTROLLING THE RESIDENCE TIME BETWEEN THE OIL AND SAID SECOND PARTICLE SPECIES TO EFFECT CATALYTIC CRACKING OF THE OIL, REMOVING THE MIXTURE OF PARTICLES FROM CONTACT WITH THE OIL, SEPARATING SAID MIXTURE INTO (1) PARTICLES OF THE FIRST SPECIES, (2) FINES OF SAID SPECIES CHARACTERIZED BY HIGH CONTEST OF SAID METAL CONTAMINANT AND PRODUCED DURING THE AFORESAID MUTUAL GRINDING AND, (3) PARTICLES OF THE SECOND SPECIES, DISCARDING SAID SEPARATED FINES, REGENERATING THE SEPARATED PARTICLES OF THE SECOND SPECIES IN AN OXIDIZING ATMOSPHERE AND RECYCLING THE SAME AFTER REGENERATION TOGETHER WITH SAID SEPARATED PARTICLES OF THE FIRST SPECIES TO SAID MOVING COMPACT BED UNDER CONDITIONS SUCH THAT THE FIRST OF SAID SPECIES IS PERFERENTIALLY SEGREGATED TO MAKE INITIAL CONTACT WITH THE OIL CHARGE