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A catalytic hydrocracking process for the production of ultra low sulfur diesel wherein a hydrocarbonaceous feedstock is hydrocracked at elevated temperature and pressure to obtain conversion to diesel boiling range hydrocarbons. The resulting hydrocracking zone effluent is hydrogen stripped in a st

A catalytic hydrocracking process for the production of ultra low sulfur diesel wherein a hydrocarbonaceous feedstock is hydrocracked at elevated temperature and pressure to obtain conversion to diesel boiling range hydrocarbons. The resulting hydrocracking zone effluent is hydrogen stripped in a stripping zone maintained at essentially the same pressure as the hydrocracking zone to produce a first gaseous hydrocarbonaceous stream and a first liquid hydrocarbonaceous stream. The first gaseous hydrocarbonaceous stream containing diesel boiling range hydrocarbons is introduced into a desulfurization zone and subsequently partially condensed to produce a hydrogen-rich gaseous stream and a second liquid hydrocarbonaceous stream containing diesel boiling range hydrocarbons. The first liquid stream is separated to produce a third liquid hydrocarbonaceous stream containing diesel boiling range hydrocarbons which is also introduced into the desulfurization zone. An ultra low sulfur diesel product stream is recovered.

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What is claimed is: 1. A hydrocracking process for the production of ultra low sulfur diesel from a hydrocarbonaceous feedstock wherein the process comprises the steps of: (a) reacting the hydrocarbonaceous feedstock and hydrogen in a hydrocracking zone containing hydrocracking catalyst to produce

What is claimed is: 1. A hydrocracking process for the production of ultra low sulfur diesel from a hydrocarbonaceous feedstock wherein the process comprises the steps of: (a) reacting the hydrocarbonaceous feedstock and hydrogen in a hydrocracking zone containing hydrocracking catalyst to produce diesel boiling range hydrocarbons; (b) stripping a hydrocracking zone effluent in a hot, high pressure stripping zone maintained at essentially the same pressure as the hydrocracking zone and a temperature in the range from about 232째 C. (450째 F.) to about 468째 C. (875째 F.) with a first hydrogen-rich gaseous stream to produce a first gaseous hydrocarbonaceous stream comprising diesel boiling range hydrocarbons and a first liquid hydrocarbonaceous stream; (c) passing the first gaseous hydrocarbonaceous stream comprising diesel boiling range hydrocarbons to a desulfurization zone containing desulfurization catalyst and producing a desulfurization zone effluent stream; (d) condensing at least a portion of the desulfurization zone effluent stream to produce a second hydrogen-rich gaseous stream and a second liquid hydrocarbonaceous stream comprising diesel boiling range hydrocarbons; (e) passing the first liquid hydrocarbonaceous stream to a hot flash zone maintained at a pressure from about 445 kPa (50 psig) to about 2858 kPa (400 psig) and a temperature from about 232째 C. (450째 F.) to about 468째 C. (875째 F.) to produce a third liquid hydrocarbonaceous stream comprising unconverted hydrocarbons and diesel boiling range hydrocarbons; (f) stripping the third liquid hydrocarbonaceous stream and introducing the resulting stripped stream in a flash column operated at a temperature from about 232째 C. (450째 F.) to about 468째 C. (875째 F.) and a pressure from about 3.5 kPa (0.5 psia) to about 196.4 kPa (28.5 psia) to produce a fourth liquid hydrocarbonaceous stream comprising unconverted hydrocarbons and a second gaseous hydrocarbonaceous stream comprising diesel boiling range hydrocarbons; (g) reacting at least a portion of the second gaseous hydrocarbonaceous stream in the desulfurization zone containing desulfurization catalyst; and (h) recovering an ultra low sulfur diesel product stream. 2. The process of claim 1 wherein at least 25% by volume of the hydrocarbonaceous feedstock boils between about 315째 C. (600째 F.) and about 538째 C. (1000째 F.). 3. The process of claim 1 wherein the hydrocracking zone is operated at conditions which include a temperature from about 232째 C. (450째 F.) to about 468째 C. (875째 F.) and a pressure from about 3.45 MPa (500 psig) to about 20.7 MPa (3000 psig). 4. The process of claim 1 wherein the conversion of the feedstock in the hydrocracking zone is preferably less than 80 volume percent, more preferably 60 volume percent and even more preferably less than 50 volume percent. 5. The process of claim 1 wherein at least a majority of the diesel boiling range hydrocarbons boils in the range from about 154째 C. (309째 F.) to about 370째 C. (698째 F.). 6. The process of claim 1 wherein at least a portion of the second hydrogen-rich gaseous stream is recycled to the hydrocracking zone in step (a). 7. The process of claim 1 wherein at least a portion of the second hydrogen-rich gaseous stream is recycled to the hot, high pressure stripping zone in step (b). 8. The process of claim 1 wherein the ultra low sulfur diesel product stream comprises less than about 50 wppm sulfur. 9. The process of claim 1 wherein the ultra low sulfur diesel product stream comprises less than about 10 wppm sulfur. 10. The process of claim 1 wherein a second feedstock comprising hydrocarbonaceous material boiling from about 180째 C. (356째 F.) to about 370째 C. (698째 F.) is introduced into and reacted in the desulfurization zone of step (c). 11. The process of claim 1 wherein the hydrocarbonaceous feedstock is selected from the group consisting of atmospheric gas oils, vacuum gas oils, deasphalted, vacuum, and atmospheric residua, hydrotreated residual oils, coker distillates, straight run distillates, pyrolysis-derived oils, high boiling synthetic oils, cycle oils and cat cracker distillates. 12. The process of claim 10 wherein the second feedstock is selected from the group consisting of visbroken distillate, light cycle oil, straight run kerosene, straight run diesel, coker distillate and tar sand derived distillate. 13. A hydrocracking process for the production of ultra low sulfur diesel from a first hydrocarbonaceous feedstock and a second hydrocarbonaceous feedstock boiling in a range lower than that of the first hydrocarbonaceous feedstock which process comprises the steps of: (a) reacting the first hydrocarbonaceous feedstock and hydrogen in a hydrocracking zone containing hydrocracking catalyst to produce diesel boiling range hydrocarbons; (b) stripping a hydrocracking zone effluent in a hot, high pressure stripping zone maintained at essentially the same pressure as the hydrocracking zone and a temperature in the range from about 232째 C. (450째 F.) to about 468째 C. (875째 F.) with a first hydrogen-rich gaseous stream to produce a first gaseous hydrocarbonaceous stream comprising diesel boiling range hydrocarbons and a first liquid hydrocarbonaceous stream; (c) passing the first gaseous hydrocarbonaceous stream comprising diesel boiling range hydrocarbons and the second hydrocarbonaceous feedstock to a desulfurization zone containing desulfurization catalyst and producing a desulfurization zone effluent stream; (d) condensing at least a portion of the desulfurization zone effluent stream to produce a second hydrogen-rich gaseous stream and a second liquid hydrocarbonaceous stream comprising diesel boiling range hydrocarbons; (e) passing the first liquid hydrocarbonaceous stream to a hot flash zone maintained at a pressure from about 445 kPa (50 psig) to about 2858 kPa (400 psig) and a temperature from about 232째 C. (450째 F.) to about 468째 C. (875째 F.) to produce a third liquid hydrocarbonaceous stream comprising unconverted hydrocarbons and diesel boiling range hydrocarbons; (f) stripping the third liquid hydrocarbonaceous stream and introducing the resulting stripped stream in a flash column operated at a temperature from about 232째 C. (450째 F.) to about 468째 C. (875째 F.) and a pressure from about 3.5 kPa (0.5 psia) to about 196.4 kPa (28.5 psia) to produce a fourth liquid hydrocarbonaceous stream comprising unconverted hydrocarbons and a second gaseous hydrocarbonaceous stream comprising diesel boiling range hydrocarbons; (g) reacting at least a portion of the second gaseous hydrocarbonaceous stream in the desulfurization zone containing desulfurization catalyst; and (h) recovering an ultra low sulfur diesel product stream. 14. The process of claim 13 wherein at least 25% by volume of the first hydrocarbonaceous feedstock boils between about 315째 C. (600째 F. ) and about 538째 C. (1000째 F.). 15. The process of claim 13 wherein at least a majority of the second hydrocarbonaceous feedstock boils in the diesel boiling range. 16. The process of claim 13 wherein the hydrocracking zone is operated at conditions which include a temperature from about 232째 C. (450째 F.) to about 468째 C. (875째 F.) and a pressure from about 3.45 MPa (500 psig) to about 20.7 MPa (3000 psig). 17. The process of claim 13 wherein at least a majority of the diesel boiling range hydrocarbons boils in the range from about 154째 C. (309째 F.) to about 370째 C. (698째 F.). 18. The process of claim 13 wherein at least a majority of the second hydrocarbonaceous feedstock boils in the range from about 180째 C. (356째 F.) to about 370째 C. (698째 F.). 19. The process of claim 13 wherein at least a portion of the second hydrogen-rich gaseous stream is recycled to the hydrocracking zone in step (a). 20. The process of claim 13 wherein at least a portion of the second hydrogen-rich gaseous stream is recycled to the hot, high pressure stripping zone in step (b). 21. The process of claim 13 wherein the ultra low sulfur diesel product stream comprises less than about 50 wppm sulfur. 22. The process of claim 13 wherein the ultra low sulfur diesel product stream comprises less than about 10 wppm sulfur. 23. The process of claim 13 wherein the first hydrocarbonaceous feedstock is selected from the group consisting of atmospheric gas oils, vacuum gas oils, deasphalted, vacuum, and atmospheric residua, hydrotreated residual oils, coker distillates, straight run distillates, pyrolysis-derived oils, high boiling synthetic oils, cycle oils and cat cracker distillates. 24. The process of claim 13 wherein the conversion of the feedstock in the hydrocracking zone is preferably less than 80 volume percent, more preferably 60 volume percent and even more preferably less than 50 volume percent. 25. The process of claim 13 wherein the second hydrocarbonaceous feedstock is selected from the group consisting of group consisting of visbroken distillate, light cycle oil, straight run kerosene, straight run diesel, coker distillate and tar sand derived distillate. 26. A hydrocracking process for the production of ultra low sulfur diesel from a first hydrocarbonaceous feedstock and a second hydrocarbonaceous feedstock boiling in a range lower than that of the first hydrocarbonaceous feedstock which process comprises the steps of: (a) reacting the first hydrocarbonaceous feedstock and hydrogen in a hydrocracking zone containing hydrocracking catalyst to produce diesel boiling range hydrocarbons boiling in the range from about 154째 C. (309째 F.) to about 370째 C. (680째 F.); (b) stripping a hydrocracking zone effluent in a hot, high pressure stripping zone maintained at essentially the same pressure as the hydrocracking zone and a temperature in the range of from about 232째 C. (450째 F.) to about 468째 C. (875째 F.) with a first hydrogen-rich gaseous stream to produce a first gaseous hydrocarbonaceous stream comprising diesel boiling range hydrocarbons and a first liquid hydrocarbonaceous stream; (c) passing the first gaseous hydrocarbonaceous stream comprising diesel boiling range hydrocarbons and the second hydrocarbonaceous feedstock to a desulfurization zone containing desulfurization catalyst and producing a desulfurization zone effluent stream; (d) condensing at least a portion of the desulfurization zone effluent stream to produce a second hydrogen-rich gaseous stream and a second liquid hydrocarbonaceous stream comprising diesel boiling range hydrocarbons; (e) passing the first liquid hydrocarbonaceous stream to a hot flash zone maintained at a pressure from about 445 kPa (50 psig) to about 2858 kPa (400 psig) and a temperature from about 232째 C. (450째 F.) to about 468째 C. (875째 F.) to produce a third liquid hydrocarbonaceous stream comprising unconverted hydrocarbons and diesel boiling range hydrocarbons; (f) stripping the third liquid hydrocarbonaceous stream and introducing the resulting stripped stream into a flash column operated at a temperature from about 232째 C. (450째 F.) to about 468째 C. (875째 F.) and a pressure from about 3.5 kPa (0.5 psia) to about 196.4 kPa (28.5 psia) to produce a fourth liquid hydrocarbonaceous stream comprising unconverted hydrocarbons and a second gaseous hydrocarbonaceous stream comprising diesel boiling range hydrocarbons; (g) reacting at least a portion of the second gaseous hydrocarbonaceous stream in the desulfurization zone containing desulfurization catalyst; and (h) recovering an ultra low sulfur diesel product stream.