Cracking catalyst demetallization

Claim 1

A METHOD FOR REMOVING NICKEL FRO, A SYNTHETIC GEL, SILICA-BASED CRACKING CATALYST WHICH HAS BEEN POISONED BY CONTAMINATION WITH NICKEL DUE TO THE USE OF SAID CATALYST INCRACKING AT ELEVATED TEMPERATURE A HYDROCARBON FEEDSTOCK CONTAINING NICKEL, WHICH COMPRISES BLEEDING A PORTION OF THE NICKEL-CONTAMINATED CATALYST FROM THE HYDROCARBON CRACKING SYSTEM, SAID BLED CATALYST BEING OUT OF CONTACT WITH THE HYDROCARBON FEEDSTOCK, SULFIDING SAID NICKEL CONTAMINANT ON THE CATALYST BY CONTACTIN BLED CATALYST AT A TEMPERATURE OF ABOUT 500 TO 1500*F. WITH A VAPOROUS SULFIDING AGENT, CONVERTING SULFIDED NICKEL CONTAMINANT TO A FORM DISPERSIBLE IN AN AQUEOUS MEDIUM BY CONTACT OF THE SULFIDED CATALYST WITH A MOLECULAR OXYGEN-CONTAINING GAS AT A TEMPERATURE FROM ABOUT ROOM TEMPERATURE TO ABOUT 1300*F., WASHING THE CATALYST WITH AN AQUEOUS MEDIUM CONSISTING ESSENTIALLY OF WATER TO REMOVE NICKEL CONTAMINANT, AND RETURNING TO A HYDROCARBON CRACKING SYSTEM CATALYST REDUCED IN NICKEL CONTAMINANT.

Claim 2

A METHOD FOR REMOVING NICKEL FRO, A SYNTHETIC GEL, SILICA-BASED CRACKING CATALYST WHICH HAS BEEN POISONED BY CONTAMINATION WITH NICKEL DUE TO THE USE OF SAID CATALYST INCRACKING AT ELEVATED TEMPERATURE A HYDROCARBON FEEDSTOCK CONTAINING NICKEL, WHICH COMPRISES BLEEDING A PORTION OF THE NICKEL-CONTAMINATED CATALYST FROM THE HYDROCARBON CRACKING SYSTEM, SAID BLED CATALYST BEING OUT OF CONTACT WITH THE HYDROCARBON FEEDSTOCK, SULFIDING SAID NICKEL CONTAMINANT ON THE CATALYST BY CONTACTIN BLED CATALYST AT A TEMPERATURE OF ABOUT 500 TO 1500*F. WITH A VAPOROUS SULFIDING AGENT, CONVERTING SULFIDED NICKEL CONTAMINANT TO A FORM DISPERSIBLE IN AN AQUEOUS MEDIUM BY CONTACT OF THE SULFIDED CATALYST WITH A MOLECULAR OXYGEN-CONTAINING GAS AT A TEMPERATURE FROM ABOUT ROOM TEMPERATURE TO ABOUT 1300*F., WASHING THE CATALYST WITH AN AQUEOUS MEDIUM CONSISTING ESSENTIALLY OF WATER TO REMOVE NICKEL CONTAMINANT, AND RETURNING TO A HYDROCARBON CRACKING SYSTEM CATALYST REDUCED IN NICKEL CONTAMINANT.

Claim 3

A METHOD FOR REMOVING A NICKEL FROM A SYNTHETIC GEL, SILICA-BASED CRACKIN GCATALYST WHICH HAS BEEN POISONED BY CONTAMINATION WITH NICKEL DUE TO USE OF SAI CATALYST IN CRACKING AT ELEVATED TEMPERATURE A HYDROCARBON FEEDSTOCK CONTAININ NICKEL, WHICH COMPRISES BLEEDING A PORTION OF THE NICKEL-CONTAMINATED CATALYST FROM THE HYDROCARBON CRACKING SYSTEM, SAID BLED CATALYST BEING OUT OF CONTACT WITH THE HYDROARBON FEEDSTOCK, SULFIDING SAID NICKEL CONTAMINANT ON THE CATALYST BY CONTACTING BLED CATALYST WITH A VAPOROUS SULFIDE AGENT AT A TEMPERATURE OF ABOUT 500 TO 1500*F., CONVERTING SULFIDED NICKEL CONTAMINANT TO A FORM DISPERSIBLE IN AN AQUEOUS MEDIUM BY CONTACT OF THE SULFIDED CATALYST WITH A LIQUID AQUEOUS OXIDING MEDIUM, WASHING THE CATALYST WITH AN AQUEOUS MEDIUM CONSISTING ESSENTIALLY OF WATER TO REMOVE NICKEL CONTAMINANT, AND RETURNING TO A CRACKIN SYSTEM CATALYST REDUCED IN NICKEL CONTAMINANT.

Claim 4

A METHOD FOR REMOVING A NICKEL FROM A SYNTHETIC GEL, SILICA-BASED CRACKIN GCATALYST WHICH HAS BEEN POISONED BY CONTAMINATION WITH NICKEL DUE TO USE OF SAI CATALYST IN CRACKING AT ELEVATED TEMPERATURE A HYDROCARBON FEEDSTOCK CONTAININ NICKEL, WHICH COMPRISES BLEEDING A PORTION OF THE NICKEL-CONTAMINATED CATALYST FROM THE HYDROCARBON CRACKING SYSTEM, SAID BLED CATALYST BEING OUT OF CONTACT WITH THE HYDROARBON FEEDSTOCK, SULFIDING SAID NICKEL CONTAMINANT ON THE CATALYST BY CONTACTING BLED CATALYST WITH A VAPOROUS SULFIDE AGENT AT A TEMPERATURE OF ABOUT 500 TO 1500*F., CONVERTING SULFIDED NICKEL CONTAMINANT TO A FORM DISPERSIBLE IN AN AQUEOUS MEDIUM BY CONTACT OF THE SULFIDED CATALYST WITH A LIQUID AQUEOUS OXIDING MEDIUM, WASHING THE CATALYST WITH AN AQUEOUS MEDIUM CONSISTING ESSENTIALLY OF WATER TO REMOVE NICKEL CONTAMINANT, AND RETURNING TO A CRACKIN SYSTEM CATALYST REDUCED IN NICKEL CONTAMINANT.