Hydrocracking-hydrogenation process

Claim 2

in an alternating periodic middle distillate-producing cycle, passing said feedstock in admixture with hydrogen through said first catalyst contacting zone as defined in step (1), separating the resulting effluent into an aromatic gasoline product and a relatively aromatic bottoms fraction comprising middle distillate and a heavier fraction, passing at least the middle distillate portion of said bottoms fraction plus added hydrogen through said second catalyst contacting zone at an elevated pressure substantially in the absence of hydrogen sulfide, and at a temperature correlated with space velocity so as to saturate at least about one-third of the aromatic hydrocarbons in said middle distillate portion but to substantially avoid cracking reactions, recovering a relatively non-aromatic middle distillate product from the resulting effluent, and recycling to said first catalytic zone a heavier fraction recovered from the effluent from said first and/or second catalytic contacting zones.

Claim 3

A process as defined in claim 1 wherein the catalyst employed in said second contacting zone is a molecular sieve zeolite having a SiO2/Al2O3 mole-ratio above about 3, at least about 20% of the ion-exchange capacity thereof being satisfied by hydrogen ions, and deposited thereon between about 0.1% and 3% by weight of palladium or platinum.

Claim 4

In an alternating periodic middle distillate-producing cycle, passing said feedstock in admixture with hydrogen through said first catalyst contacting zone as defined in step (1), separating the resulting effluent into an aromatic gasoline product and a relatively aromatic unconverted higher-boiling fraction, passing said higher-boiling fraction plus added hydrogen through said second catalyst contacting zone at an elevated pressure and substantially in the absence of hydrogen sulfide and at a substantially non-cracking temperature below about 450* F., correlated with space velocity so as to saturate at least about one-third of the aromatic hydrocarbons in said unconverted oil which synthesizing less than about 5 volume-percent of C4-400* F. gasoline by hydrocracking, and recovering a relatively non-aromatic middle distillate product from the resulting effluent.

Claim 5

in a periodic gasoline-producing cycle: a. passing effluent from said hydrofining zone, without intervening purification to remove ammonia and hydrogen sulfide, through a second Catalytic contacting zone at an elevated pressure and a temperature between about 625* and 850* F., in contact with a hydrocracking catalyst comprising a minor proportion of a Group VIII metal and/or an oxide or sulfide thereof supported on a crystalline zeolitic cracking base wherein at least half of the original zeolitic sodium ions have been replaced by hydrogen ions, polyvalent metal ions, decationized sites, or a combination thereof, to thereby effect about 30-80 volume-percent conversion per pass to gasoline-boiling range material, b. separating the effluent therefrom into an aromatic gasoline product, and an unconverted higher boiling fraction, c. passing said unconverted higher boiling fraction through a third catalytic contacting zone in admixture with hydrogen and hydrogen sulfide at an elevated pressure and a temperature between about 500* and 850* F. in the presence of a hydrocracking catalyst as defined in step 2-(a), wherein the Group VIII metal is a noble metal, d. separating effluent from said third contacting zone into an aromatic gasoline product and an unconverted recycle oil, and e. recycling said unconverted recycle oil to said second and/or third contacting zone; and

Claim 6

in an alternating periodic middle distillate producing cycle: a. continuing the operating of said hydrofining step (1) and said second contacting zone as defined in steps (2)-(a) and (2)-(b), b. passing said unconverted higher boiling fraction through said third catalytic contacting zone in admixture with hydrogen, but substantially in the absence of hydrogen sulfide, and at a substantially non-cracking temperature between about 250* and 450* F., correlated with space velocities above about 1.0 so as to saturate at least about one-third of the aromatic hydrocarbons in said unconverted oil while synthesizing less than about 5 volume-percent of C4-400* F. gasoline by hydrocracking, the conversion to hydrocarbons boiling below 530* F. being less than about 15 volume-percent; and c. recovering said relatively non-aromatic middle distillate product from the effluent of said third contacting zone.

Claim 7

A process as defined in claim 1 wherein the entire bottoms fraction recovered from the effluent from said first contacting zone in step (2) is passed through said second contacting zone, and wherein the effluent from said second contacting zone in step (2) is fractionated to recover said non-aromatic middle distillate product and said heavier fraction, and wherein said heavier fraction is recycled to said first contacting zone.

Claim 8

in an alternating periodic middle distillate producing cycle: a. continuing the operation of said hydrofining step (1) and said second contacting zone as defined in steps (2)(a) and (2)(b), b. passing at least the middle distillate portion of said bottoms fraction through said third catalytic contacting zone in admixture with hydrogen, but substantially in the absence of hydrogen sulfide, and at a temperature correlated with space velocity so as to saturate at least about one-third of the aromatic hydrocarbons in said middle distillate portion, but to substantially avoid cracking reactions, c. recovering said relatively non-aromatic middle distillate product from the effluent of said third contacting zone; and d. recycling to said second contacting zone the heavier fraction boiling above said middle-distillate product, said heavier fraction being recovered from the effluent from said second and/or third contacting zones.

Claim 9

A process as defined in claim 1 wherein said bottoms fraction recovered from the effluent from said first contacting zone in step (2) is further fractionated to separate said middle distillate from said heavier fraction, and wherein the separated heavier fraction is recycled to said first contacting zone.

Claim 10

A process as defined in claim 1 wherein said relatively non-aromatic middle distillate product is a jet fuel boiling in a range of about 350* -530* F.

Claim 11

A process as defined in claim 1 wherein a temperature between about 200* and 500* F. is maintained during step (2) in said second contacting zone.

Claim 12

In a catalytic hydrofining-hydrocracking-hydrogenation system, a process for converting a mineral oil feedstock boiling above the gasoline range alternately to a relatively aromatic gasoline product, and to a plurality of products including an aromatic gasoline and a relatively non-aromatic middle distillate product boiling at least partially above the gasoline range, said feedstock also comprising a heavy fraction boiling above the end-boiling-point of said middle distillate product, which comprises:

Claim 13

A process as defined in claim 7 wherein the catalyst employed in said third contacting zone is a molecular sieve zeolite having a SiO2/Al2O2 mole-ratio above about 3, at least about 20% of the ion-exchange capacity thereof being satisfied by hydrogen ions, and deposited thereon between about 0.1 and 3% by weight of palladium or platinum.

Claim 14

A process as defined in claim 7 wherein the entire bottoms fraction recovered from the effluent from said second contacting zone in step (3)(a) is passed through said third contacting zone, and wherein the effluent from said third contacting zone in step (3) is fractionated to recover said non-aromatic middle distillate product and said heavier fraction, and wherein said heavier fraction is recycled to said second contacting zone.

Claim 15

A process as defined in claim 7 wherein said relatively non-aromatic middle distillate product is a jet fuel boiling in the range of about 350* -530* F.

Claim 16

A process as defined in claim 7 wherein the bottoms fraction recovered from the effluent from said second contacting zone in step (3)(a) is further fractionated to separate said middle distillate from said heavier fraction, and wherein the separated heavier fraction is recycled to said second contacting zone.

Claim 17

A process as defined in claim 7 wherein a temperature between about 200* and 500* F. is maintained during step (3)(b) in said third contacting zone.

Claim 18

In a catalytic hydrocracking-hydrogenation system, a process for converting a mineral oil feedstock containing aromatic hydrocarbons and boiling above the gasoline range alternately to a relatively aromatic gasoline product, and to a plurality of products including an aromatic gasoline and a substantial proportion of a relatively non-aromatic middle-distillate product boiling at least partially above the gasoline range, which comprises:

Claim 19

A process as defined in claim 13 wherein the catalyst employed in said second contacting zone is a molecular sieve zeolite having a SiO2/Al2O3 mole-ratio above about 3, at least about 20% of the ion-exchange capacity thereof being satisfied by hydrogen ions, and deposited thereon between about 0.1 and 3 percent by weight of palladium or platinum.

Claim 20

A process as defined in claim 13 wherein the effluent from said second contacting zone in step (2) is fractionated to recover said non-aromatic middle distillate product and a higher boiling recycle fraction, and wherein said higher boiling recycle fraction is recycled to said first contacting zone.

Claim 21

A process as defined in claim 13 wherein said relatively non-aromatic middle distillate product is a jet fuel boiling in a range of about 350*-530* F.

Claim 22

A process as defined in claim 13 wherein a temperature between about 250* and 450* F. is maintained during step (2) in said second contacting zone.

Claim 23

In a catalystic hydrofining-hydrocracking-hydrogenation system, a process for converting a mineral oil feedstock boiling above the gasoline range alternately to a relatively aromatic gasoline product, and to a plurality of products including an aromatic gasoline and a relatively non-aromatic middle distillate product boiling at least partially above the gasoline range, which comprises:

Claim 24

A process as defined in claim 18 wherein the catalyst employed in said third contacting zone is a molecular sieve zeolite having a SiO2/Al2O3 mole-ratio above about 3, at least about 20% of the ion-exchange capacity thereof being satisfied by hydrogen ions, and deposited thereon between about 0.1 and 3% by weight of palladium or platinum.

Claim 25

A process as defined in claim 18 wherein the effluent from said third contacting zone in step (3) is fractionated to recover said non-aromatic middle distillate product, and a higher boiling recycle fraction, and wherein said higher boiling fraction is recycled to said second contacting zone.

Claim 26

A process as defined in claim 18 wherein said relatively non-aromatic middle distillate product is a jet fuel boiling in a range of about 350* - 530* F.

Claim 27

A process as defined in claim 18 wherein the aromatic content of the unconverted oil fed to said third contacting zone is above 30 volume-percent and the aromatic content of the middle distillate product is below 20 volume percent.

Claim 29

A process as defined in claim 23 wherein said Group VIII noble metal is palladium.

Claim 30

A process as defined in claim 23 wherein the conversion of middle distillate is less than 10 volume percent.