Process for continuous hydrocarbon conversion with a silica-aluminachromium oxide catalyst

Claim 1

IN A PROCESS FOR CONTINUOUS CATALYTIC CONVERSION OF HEAVIER HYDROCARBONS BY CATALYTIC CRACKING TO HYDROCARBONS WITHIN THE GASOLINE BOILING RANGE CHARACTERIZED BY THE STEPS OF PASSING A PARTICLE-FORM CATALYST CONTAINING A MAJOR PROPORTION OF SILICA AND A MINOR PROPORTION OF ALUMINA DOWNWARDLY AS A COMPACT MOVING BED THROUGH A CONVERSION ZONE, CONTACTING SAID HEAVIER HYDROCARBONS WITH SAID CATALYST IN SAID CONVERSION ZONE TO INDUCE SAID CONVERSION WITH CONCOMITANT DEPOSITION ON SAID CATALYST OF A COMBUSTIBLE CONTAMINATING DEPOSIT, THEREAFTER PASSING CATALYST FROM SAID CONVERSION ZONE CARRYING SAID DEPOSIT DOWNWARDLY THROUGH A PLURALITY OF REGENERATION ZONES IN SERIES AS A SUBSTANTIALLY COMPACT MOVING BED, PASSING COMBUSTION-SUPPORTING GAS IN CONTACT WITH SAID CATALYST IN SAID REGENERATION ZONES TO BURN OFF SAID COMBUSTIBLE DEPOSIT, THEREBY FORMING REGENERATION FUME AS A RESULT OF BURNING SAID DEPOSIT OF WHICH THE FUME FROM THE EARLIER OF THE ZONES HAS A TENDENCY TO BURN IN FLUES AND THE LIKE DUE TO THE RELATIVELY LOW RATIO OF CARBON DIOXIDE TO CARBON MONOXIDE THEREIN WHEN SAID CATALYST CONSISTS OF SILICA AND ALUMINA AND THEREAFTER RETURNING THE REGENERATED CATALYST TO SAID CONVERSION ZONE; THE IMPROVEMENT WHICH COMPRISES CIRCULATING AS SAID CATALYST A PARTICLE-FORM COMPOSITE OF SILICA, ALUMINA AND CHROMIUM OXIDE IN WHICH THE CHROMIUM OXIDE CONSTITUTES FROM ABOUT 0.01 TO ABOUT 1.0 PER CENT BY DRY WEIGHT, SAID CATALYST BEING TEMPERED IN A SUBSTANTIALLY DRY ATMOSPHERE AT A TEMPERATURE BETWEEN ABOUT 1100* F. AND 1400* F. AFTER PASSAGE THROUGH SAID CONVERSION ZONE AND BEFORE RETURN TO SAID CONVERSION ZONE.