Integrated process for the production of low sulfur diesel

1. An integrated process for the production of ultra-low sulfur diesel from low quality feedstocks which process comprises:

(a) reacting an asphaltene-containing feedstock having at least a portion boiling at greater than 565° C. (1050° F.) and hydrogen in a hydrodesulfurization reaction zone containing hydrodesulfurization catalyst to produce a hydrodesulfurization reaction zone effluent stream comprising diesel boiling range hydrocarbons and having a reduced concentration of sulfur, and hydrogen;

(b) separating the hydrodesulfurization reaction zone effluent stream to provide a vaporous stream comprising both diesel boiling range hydrocarbons and hydrogen, and a liquid hydrocarbonaceous stream comprising asphaltenes and having a reduced concentration of sulfur;

(c) reacting the vaporous stream comprising diesel boiling range hydrocarbons and hydrogen from step (b) and a distillate hydrocarbon feedstock in a hydrocracking zone containing hydrocracking catalyst to produce a hydrocracking zone effluent stream comprising lower boiling hydrocarbons, diesel boiling range hydrocarbons having a reduced sulfur concentration, and hydrogen; and

(d) separating the hydrocracking zone effluent stream comprising lower boiling hydrocarbons, diesel boiling range hydrocarbons having a reduced sulfur concentration, and hydrogen to provide a hydrogen rich gaseous stream and diesel boiling range hydrocarbons having a reduced concentration of sulfur.

2. The process of claim 1 wherein at least 25 volume percent of the asphaltene-containing feedstock of step (a) boils at a temperature greater than 565° C. (1050° F.).

3. The process of claim 1 wherein the distillate hydrocarbon feedstock in step (c) boils in the range from about 315° C. (600° F.) to about 565° C. (1050° F.).

4. The process of claim 1 wherein the hydrodesulfurization reaction zone is operated at conditions including a pressure from about 7.0 MPa (1000 psig) to about 20.7 MPa (3000 psig) and a temperature from about 204° C. (400° F.) to about 454° C. (850° F.).

5. The process of claim 1 wherein the hydrocracking zone is operated at conditions including a pressure from about 7.0 MPa (1000 psig) to about 20.7 MPa (3000 psig) and a temperature from about 260° C. (500° F.) to about 426° C. (800° F.).

6. The process of claim 1 wherein the diesel boiling range hydrocarbons having a reduced concentration of sulfur contain less than about 100 ppm sulfur.

7. An integrated process for the production of ultra-low sulfur diesel from low quality feedstocks which process comprises:

(a) reacting an asphaltene-containing feedstock having at least a portion boiling at greater than 565° C. (1050° F.) and hydrogen in a hydrodesulfurization reaction zone containing hydrodesulfurization catalyst and operated at conditions including a pressure from about 7.0 MPa (1000 psig) to about 20.7 MPa (3000 psig) and a temperature from about 204° C. (400° F.) to about 454° C. (850° F.) to produce a hydrodesulfurization reaction zone effluent stream comprising diesel boiling range hydrocarbons and having a reduced concentration of sulfur, and hydrogen;

(b) separating the hydrodesulfurization reaction zone effluent stream to provide a vaporous stream comprising both diesel boiling range hydrocarbons and hydrogen, and a liquid hydrocarbonaceous stream comprising asphaltenes and having a reduced concentration of sulfur;

(c) reacting the vaporous stream comprising diesel boiling range hydrocarbons and hydrogen from step (b) and a distillate hydrocarbon feedstock in a hydrocracking zone containing hydrocracking catalyst and operated at conditions including a pressure from about 7.0 MPa (1000 psig) to about 20.7 MPa (3000 psig) and a temperature from about 260° C. (500° F.) to about 454° C. (850° F.) to produce a hydrocracking zone effluent stream comprising lower boiling hydrocarbons, diesel boiling range hydrocarbons having a reduced sulfur concentration, and hydrogen; and

(d) separating the hydrocracking zone effluent stream comprising lower boiling hydrocarbons, diesel boiling range hydrocarbons having a reduced sulfur concentration, and hydrogen to provide a hydrogen rich gaseous stream and diesel boiling range hydrocarbons having a reduced concentration of sulfur.

8. The process of claim 7 wherein at least 25 volume percent of the asphaltene-containing feedstock of step (a) wherein boils at a temperature greater than 565° C. (1050° F.).

9. The process of claim 7 wherein the distillate hydrocarbon feedstock in step (c) boils in the range from about 315° C. (600° F.) to about 565° C. (1050° F.).

10. The process of claim 7 wherein the diesel boiling range hydrocarbons having a reduced concentration of sulfur contain less than about 100 ppm sulfur.

11. An integrated process for the production of ultra-low sulfur diesel from low quality feedstocks which process comprises:

(a) reacting an asphaltene-containing feedstock having at least 25 volume percent boiling at a temperature greater than 565° C. (1050° F.), and hydrogen in a hydrodesulfurization reaction zone containing hydrodesulfurization catalyst and operated at conditions including a pressure from about 7.0 MPa (1000 psig) to about 20.7 MPa (3000 psig) and a temperature from about 204° C. (400° F.) to about 454° C. (850° F.) to produce a hydrodesulfurization reaction zone effluent steam comprising diesel boiling range hydrocarbons and having a reduced concentration of sulfur, and hydrogen;

(b) separating the hydrodesulfurization reaction zone effluent stream to provide a vaporous stream comprising both diesel boiling range hydrocarbons and hydrogen, and a liquid hydrocarbonaceous stream containing asphaltenes and having a reduced concentration of sulfur;

(c) reacting the vaporous stream comprising diesel boiling range hydrocarbons and hydrogen from step (b) and a distillate hydrocarbon feedstock boiling in the range from about 315° C. (600° F.) to about 565° C. (1050° F.) in a hydrocracking zone containing hydrocracking catalyst and operated at conditions including a pressure from about 7.0 MPa (1000 psig) to about 20.7 MPa (3000 psig) and a temperature from about 260° C. (500° F.) to about 454° C. (850° F.) to produce a hydrocracking zone effluent stream comprising lower boiling hydrocarbons, diesel boiling range hydrocarbons having a reduced sulfur concentration, and hydrogen; and

(d) separating the hydrocracking zone effluent stream comprising lower boiling hydrocarbons, diesel boiling range hydrocarbons having a reduced sulfur concentration and hydrogen to provide a hydrogen rich gaseous stream and diesel boiling range hydrocarbons having a reduced concentration of sulfur.

12. The process of claim 11 wherein the diesel boiling range hydrocarbons having a reduced concentration of sulfur contain less than about 100 ppm sulfur.