Catalytic cracking process

Claim 2

A process for the production of a high octane gasoline comprising cracking a sulfur-bearing hydrocarbon feed in a first cracking zone over a cracking catalyst at conditions sufficient to obtain a cat cracked naphtha product containing from about 10 percent to about 60 percent olefins, based on the weight of said product, withdrawing said cat cracked naphtha as a product from said first cracking zone, splitting said product into components inclusive of a fraction having a low end boiling point ranging from about 150° F. to about 250° F. and a high end boiling point ranging from about 350° F. to about 450° F., recracking said cat cracked naphtha fraction, without dilution with other hydrocarbons, over a crystalline aluminosilicate zeolite catalyst in a second cracking zone to desulfurize said feed, and saturate at least about 50 percent of said olefins, based on the weight of said cat cracked naphtha, hydrofining the product of said second cracking zone over a hydrogenation catalyst at hydrofining conditions in a hydrofining zone to hydrodesulfurize said product, and saturate sufficient of the olefins to form a product suitable for addition to a gasoline blending pool.

Claim 3

The process of claim 1 wherein the sulfur-bearing hydrocarbon feed introduced into said first cracking zone is a gas oil boiling below about 1050° F.

Claim 4

The process of claim 2 wherein the gas oil boils within a range of from about 600° F. to about 1050° F.

Claim 5

The process of claim 1 wherein the cat cracked naphtha product of said first cracking zone contains from about 20 percent to about 40 percent olefins.

Claim 6

The process of claim 1 wherein from about 80 to about 100 percent of the olefins of the cat cracked naphtha feed introduced into the second cracking zone is saturated during the reaction.

Claim 7

The process of claim 1 wherein the cat cracked naphtha feed introduced into the second cracking zone is reacted at temperature ranging from about 800° F. to about 1100° F. and at a pressure ranging from about 0 to about 50 psig.

Claim 8

The process of claim 1 wherein the cat cracked naphtha feed introduced into the second cracking zone is reacted at a temperature ranging from about 900° F. to about 1030° F. and at a pressure ranging from about 5 psig to about 20 psig.

Claim 9

The process of claim 1 wherein the cat cracked naphtha obtained as a product from said first cracking zone is split into components inclusive of a fraction having a low end boiling point ranging from about 180° F. to about 220° F. and a high end boiling point ranging from about 400° F. to about 430° F., and said fraction is recracked in the second cracking zone by contact thereof with said crystalline aluminosilicate zeolite catalyst.

Claim 10

The process of claim 1 wherein the cat cracked naphtha obtained as a product from said first cracking zone is split into components inclusive of an intermediate fraction having a low end boiling point ranging from about 150° F. to about 250° F. and a high end boiling point ranging from about 250° F. to about 380° F., and said intermediate fraction is recracked in the second cracking zone by contact thereof with said crystalline aluminosilicate zeolite catalyst.

Claim 11

A process for the production of a high octane gasoline comprising cracking a sulfur-bearing hydrocarbon feed in a first cracking zone over a cracking catalyst at conditions sufficient to obtain a cat cracked naphtha product containing from about 10 percent to about 60 percent olefins, based on the weight of said product, withdrawing said cat cracked naphtha as a product from said first cracking zone, splitting said product into components inclusive of a fraction having a low end boiling point ranging from about 180° F. to about 220° F. and a high end boiling point ranging from about 400° F. to about 430° F., recracking said cat cracked naphtha product, without dilution with other hydrocarbon feed, over a crystalline aluminosilicate zeolite catalyst in a second cracking zone to desulfurize said feed, and saturate from about 80 percent to about 100 percent of said olefins, based on the weight of said cat cracked naphtha, and then hydrofining the product of said second cracking zone over a hydrogenation catalyst at hydrofining conditions in a hydrofining zone to hydrodesulfurize said product, and saturate sufficient of the olefins to form a product suitable for addition to a gasoline blending pool.

Claim 12

A process for the production of a high octane gasoline comprising cracking a sulfur-bearing hydrocarbon feed in a first cracking zone over a cracking catalyst at conditions sufficient to obtain a cat cracked naphtha product containing from about 10 percent to about 60 percent olefins, based on the weight of said product, withdrawing said cat cracked naphtha as a product from said first cracking zone, splitting said product into components inclusive of a fraction having a low end boiling point ranging from about 180° F. to about 220° F. and a high end boiling point ranging from about 400° F. to about 430° F., recracking said cat cracked naphtha product, without dilution with other hydrocarbon feed, over a crystalline aluminosilicate zeolite catalyst in a second cracking zone to desulfurize said feed, and saturate from about 80 percent to about 100 percent of said olefins, based on the weight of said cat cracked naphtha, and then hydrofining the product of said second cracking zone over a hydrogenation catalyst at hydrofining conditions in a hydrofining zone to hydrodesulfurize said product, and saturate sufficient of the olefins to form a product suitable for addition to a gasoline blending pool.

Claim 13

The process of claim 10 wherein the sulfur-bearing hydrocarbon feed introduced into said first cracking zone is a gas oil boiling below about 1050° F.

Claim 14

The process of claim 11 wherein the gas oil boils within a range of from about 600° F. to about 1050° F.

Claim 15

The process of claim 10 wherein the cat cracked naphtha product of said first cracking zone contains from about 20 percent to about 40 percent olefins.

Claim 16

The process of claim 10 wherein the cat cracked naphtha feed introduced into the second cracking zone is reacted at a temperature ranging from about 800° F. to about 1100° F. and at a pressure ranging from about 0 to about 50 psig.

Claim 17

The process of claim 11 wherein the cat cracked naphtha feed introduced into the second cracking zone is reacted at temperature ranging from about 900° F. to about 1030° F. and at a pressure ranging from about 5 psig to about 20 psig.