Process for revivifying contaminated cracking catalysts

Claim 2

A PROCESS FOR REVIVIFYING A CONTAMINATED SILICA-ALUMINA CRACKING CATALYST WHICH COMPRISES HEATING A CONVENTIONALLY REGENERATED SILICA-ALUMINA CATALYST CONTAINING BETWEEN ABOUT 0.05% AND 0.5% BY WEIGHT OF AN INORGANIC ALKALINE METAL OXIDE TO A TEMPERATURE BETWEEN ABOUT 1250*F. AND 1750*F. FOR A TIME BETWEEN ABOUT 1 AND 3 HOURS IN THE SUBSTANTIAL ABSENCE OF STEAM.

Claim 3

A PROCESS FOR RESTORING SELECTIVITY AND ACTIVITY TO A CRACKING SILICA-ALUMINA CATALYST CONTAMINATED DURING CRACKING WHICH COMPRISES ADDING TO SAID CATALYST A SMALL AMOUNT OF ALKALINE MATERIAL SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL OXIDES AND ALKALINE EARTH METAL OXIDES SO THAT THE SAID CATALYST WILL CONTAIN BETWEEN ABOUT 0.05% AND 0.5% BY WEIGHT OF SAID ALKALINE MATERIAL AND THEN HEAT TREATING THE TREATED CATALYST FOR ABOUT 1 TO 3 HOURS AT A TEMPERATURE BETWEEN ABOUT 1250*F. AND THE 1750*F. IN THE SUBSTANTIAL ABSENCE OF STEAM.

Claim 4

A PROCESS FOR RESTORING SELECTIVITY AND ACTIVITY TO A CRACKING SILICA-ALUMINA CATALYST CONTAMINATED DURING CRACKING WHICH COMPRISES ADDING TO SAID CATALYST A SMALL AMOUNT OF ALKALINE MATERIAL SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL OXIDES AND ALKALINE EARTH METAL OXIDES SO THAT THE SAID CATALYST WILL CONTAIN BETWEEN ABOUT 0.05% AND 0.5% BY WEIGHT OF SAID ALKALINE MATERIAL AND THEN HEAT TREATING THE TREATED CATALYST FOR ABOUT 1 TO 3 HOURS AT A TEMPERATURE BETWEEN ABOUT 1250*F. AND THE 1750*F. IN THE SUBSTANTIAL ABSENCE OF STEAM.

Claim 5

IN A PROCESS FOR THE CATALYST CRACKING OF HYDROCARBONS TO PRODUCE LOWER BOILING HYDROCARBONS WHEREIN SILICA-ALUMINA CATALYST PARTICLES CONTAINING BETWEEN ABOUT 0.05% AND 0.5% BY WEIGHT OF AN INORGANIC ALKALINE METAL OXIDE ARE CIRCULATED IN A SYSTEM BETWEEN A REGENERATION ZONE MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 900*F. AND 1150*F. AND A CRACKING ZONE MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 850*F. AND 1000*F. AND THE CATALYST PARTICLES BECOME CONTAMINATED DURING CRACKING AFTER A PERIOD OF USE AND SELECTIVITY AND THE ACTIVITY OF THE SILICA-ALUMINA CATALYST ARE REDUCED, THE IMPROVEMENT WHICH COMPRISES WITHDRAWING REGENERATED SILICA-ALUMINA CATALYST OF REDUCED ACTIVITY AND SELECTIVITY FROM SAID REGENERATION ZONE AND PASSING IT TO A HEAT TREATING ZONE, HEATING SAID WITHDRAWN REGENERATED CATALYST IN SAID HEAT TREATING ZONE TO A TEMPERATURE BETWEEN ABOUT 1250*F. AND 1750*F. SUBSTANTIALLY AT ATMOSPHERIC PRESSURE IN THE SUBSTANTIAL ABSENCE OF STEAM FOR ABOUT 1 TO 3 HOURS, AND THEN RETURNING THE SO-HEATED CATALYST FROM SAID HEAT TREATING ZONE TO SAID REGENERATION ZONE.

Claim 6

IN A PROCESS FOR THE CATALYST CRACKING OF HYDROCARBONS TO PRODUCE LOWER BOILING HYDROCARBONS WHEREIN SILICA-ALUMINA CATALYST PARTICLES CONTAINING BETWEEN ABOUT 0.05% AND 0.5% BY WEIGHT OF AN INORGANIC ALKALINE METAL OXIDE ARE CIRCULATED IN A SYSTEM BETWEEN A REGENERATION ZONE MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 900*F. AND 1150*F. AND A CRACKING ZONE MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 850*F. AND 1000*F. AND THE CATALYST PARTICLES BECOME CONTAMINATED DURING CRACKING AFTER A PERIOD OF USE AND SELECTIVITY AND THE ACTIVITY OF THE SILICA-ALUMINA CATALYST ARE REDUCED, THE IMPROVEMENT WHICH COMPRISES WITHDRAWING REGENERATED SILICA-ALUMINA CATALYST OF REDUCED ACTIVITY AND SELECTIVITY FROM SAID REGENERATION ZONE AND PASSING IT TO A HEAT TREATING ZONE, HEATING SAID WITHDRAWN REGENERATED CATALYST IN SAID HEAT TREATING ZONE TO A TEMPERATURE BETWEEN ABOUT 1250*F. AND 1750*F. SUBSTANTIALLY AT ATMOSPHERIC PRESSURE IN THE SUBSTANTIAL ABSENCE OF STEAM FOR ABOUT 1 TO 3 HOURS, AND THEN RETURNING THE SO-HEATED CATALYST FROM SAID HEAT TREATING ZONE TO SAID REGENERATION ZONE.