Removing metal contaminants from silica-based cracking catalysts

Claim 1

A METHOD FOR REMOVING METAL CONTAMINANTS FROM A SYNETHTIC GEL, SILICA-BASED CRACKING CATALYST WHICH HAS BEEN POISINEED BY CONTAMINATIN WITH A METAL SELECTED FROM THE GROUP CONSISTING OF NICKEL AND VANADIUM DUE TO USE OF SAID CATALYST IN A CRACKING SYTEM WHEREIN GASOLINE IS PRODUCED AND CATALYST IS CYCLED BEETWEEN A CRACKING ZONE, IN WHICH THE CATALYST IS CONTACTED AT AN ELEVATED TEMPERATURE WITH A HYDROCRBON FEEDSTOCK BOILING ABOVE GASOLINE AND CONTAINING SAID METAL WHICH DEPOSITS ON THE CATALYST, AND A REGENERATION ZONE, IN WHICH CARBON IS OXDIZED AND THEREBY REMOVED FROM THE CATALYST, WHICH CONSISTS ESSENTAILLY OF BLEDING A PORTION OF MEAL CONTAMINATED CATALYST FROM THE CRACKING SYSTEM, CONACTING BLED, SUBSTANTIALLY CARBON-FREE CATALYST FOR AT LEAST ABOUT 15 MINUTES WITH A GAS CONTAINING MOLECULAR OXYGEN AT A TEMPERATURE OF AT LEAST ABOUT 1000*F. BUT BELOW A TEMPERATURE DELETERIOUS TO THE CATALYST TO INCREASE SUBSEQUENT METAL REMOVAL FROM SAID CATALYST, SULFIDING THE METAL CONTAMINATED, OXYGEN-TREATED CATALYST BY CONTACT WITH A SULFIDING VAPOR AT A TEMPERATRU OF ABOUT 700 TO 1600* F., REMOVING CONTAMINATING METAL SULFIDE FROM THE CATALYST BY CONTACT WITH AN AQUEOUS MINERAL ACID SOLVENT FOR THE CONTAMINATING METAL SULFIDE AND RETURNING RESULTING DEMEALLIZED CATALYST TO A HYDROCARBON CRACKING SYSTEM.

Claim 2

A METHOD FOR REMOVING METAL CONTAMINANTS FROM A SYNETHTIC GEL, SILICA-BASED CRACKING CATALYST WHICH HAS BEEN POISINEED BY CONTAMINATIN WITH A METAL SELECTED FROM THE GROUP CONSISTING OF NICKEL AND VANADIUM DUE TO USE OF SAID CATALYST IN A CRACKING SYTEM WHEREIN GASOLINE IS PRODUCED AND CATALYST IS CYCLED BEETWEEN A CRACKING ZONE, IN WHICH THE CATALYST IS CONTACTED AT AN ELEVATED TEMPERATURE WITH A HYDROCRBON FEEDSTOCK BOILING ABOVE GASOLINE AND CONTAINING SAID METAL WHICH DEPOSITS ON THE CATALYST, AND A REGENERATION ZONE, IN WHICH CARBON IS OXDIZED AND THEREBY REMOVED FROM THE CATALYST, WHICH CONSISTS ESSENTAILLY OF BLEDING A PORTION OF MEAL CONTAMINATED CATALYST FROM THE CRACKING SYSTEM, CONACTING BLED, SUBSTANTIALLY CARBON-FREE CATALYST FOR AT LEAST ABOUT 15 MINUTES WITH A GAS CONTAINING MOLECULAR OXYGEN AT A TEMPERATURE OF AT LEAST ABOUT 1000*F. BUT BELOW A TEMPERATURE DELETERIOUS TO THE CATALYST TO INCREASE SUBSEQUENT METAL REMOVAL FROM SAID CATALYST, SULFIDING THE METAL CONTAMINATED, OXYGEN-TREATED CATALYST BY CONTACT WITH A SULFIDING VAPOR AT A TEMPERATRU OF ABOUT 700 TO 1600* F., REMOVING CONTAMINATING METAL SULFIDE FROM THE CATALYST BY CONTACT WITH AN AQUEOUS MINERAL ACID SOLVENT FOR THE CONTAMINATING METAL SULFIDE AND RETURNING RESULTING DEMEALLIZED CATALYST TO A HYDROCARBON CRACKING SYSTEM.