Hydrocracking Process

Abstract

A catalytic hydrocracking process wherein a liquid phase stream comprising a hydrocarbonaceous feedstock, a liquid phase effluent from a hydrocracking zone, and a sufficiently low hydrogen concentration to maintain a liquid phase continuous system is fed into a hydrotreating zone to produce a first hydrocarbonaceous stream comprising hydrocarbons having a reduced level of sulfur and nitrogen. The resulting hydrocarbons having a reduced level of sulfur and nitrogen are introduced into a hydrocracking zone with a sufficiently low hydrogen concentration to maintain a liquid phase continuous system to produce a hydrocracking zone effluent which provides lower boiling range hydrocarbons.

1 . A process for hydrocracking a hydrocarbonaceous feedstock which comprises:
 (a) introducing a liquid phase stream comprising a hydrocarbonaceous feedstock, at least a portion of a liquid phase effluent from a hydrocracking zone and a sufficiently low hydrogen concentration to maintain a liquid phase continuous system into a hydrotreating zone to produce hydrogen sulfide and ammonia, and provide a first hydrocarbonaceous stream comprising hydrocarbons having a reduced level of sulfur and nitrogen;   (b) introducing at least a portion of the first hydrocarbonaceous stream comprising hydrocarbons having a reduced level of sulfur and nitrogen into the hydrocracking zone with a sufficiently low hydrogen concentration to maintain a liquid phase continuous system;   (c) separating a second hydrocarbonaceous stream selected from the group consisting of the first hydrocarbonaceous stream comprising hydrocarbons having a reduced level of sulfur and nitrogen, and an effluent from the hydrocracking zone in a separation zone to provide hydrocracked hydrocarbons boiling in a temperature range lower than the hydrocarbonaceous feedstock;   (d) recovering the hydrocracked hydrocarbons boiling in a temperature range lower than the hydrocarbonaceous feedstock; and   (e) recycling at least a portion of the effluent from the hydrocracking zone to step (a).   
   
   
       2 . The process of  claim 1  wherein the hydrocarbonaceous feedstock boils in the range from about 315° C. (600° F.) to about 565° C. (1050° F.). 
   
   
       3 . The process of  claim 1  wherein the hydrotreating zone is operated at conditions including a temperature from about 204° C. (400° F.) to about 482° C. (900° F.) and a pressure from about 3.5 MPa (500 psig) to about 17.3 MPa (2500 psig). 
   
   
       4 . The process of  claim 1  wherein the recovery of the unconverted hydrocarbons boiling in the range of the hydrocarbonaceous feedstock is conducted in a high pressure product stripper. 
   
   
       5 . The process of  claim 1  wherein the ratio of the unconverted hydrocarbons boiling in the range of the hydrocarbonaceous feedstock to the hydrocarbonaceous feedstock is from about 1:5 to about 3:5. 
   
   
       6 . The process of  claim 1  wherein the recovery of the unconverted hydrocarbons boiling in the range of the hydrocarbonaceous feedstock is conducted in a fractionation zone. 
   
   
       7 . The process of  claim 1  wherein the hydrocracking zone is operated at conditions including a temperature from about 232° C. (450° F.) to about 468° C. (875° F.) and a pressure from about 3.5 MPa (500 psig) to about 17.3 MPa (2500 psig). 
   
   
       8 . A process for hydrocracking a hydrocarbonaceous feedstock which comprises:
 (a) introducing a liquid phase stream comprising a hydrocarbonaceous feedstock, a liquid phase effluent from a hydrocracking zone, and a sufficiently low hydrogen concentration to maintain a liquid phase continuous system into a hydrotreating zone to produce hydrogen sulfide and ammonia and provide a hydrocarbonaceous stream comprising hydrocarbons having a reduced level of sulfur and nitrogen;   (b) recovering unconverted hydrocarbons boiling in the range of the hydrocarbonaceous feedstock, hydrogen sulfide and ammonia from the hydrocarbonaceous stream;   (c) introducing the unconverted hydrocarbons boiling in the range of the hydrocarbonaceous feedstock recovered in step (b) into the hydrocracking zone with a sufficiently low hydrogen concentration to maintain a liquid phase continuous system and;   (d) introducing the hydrocracking zone effluent from step (c) into the hydrotreating zone in step (a), and;   (e) recovering hydrocracked hydrocarbons boiling in a temperature range lower than the hydrocarbonaceous feedstock.   
   
   
       9 . The process of  claim 8  wherein the hydrocarbonaceous feedstock boils in the range from about 315° C. (600° F.) to about 565° C. (1050° F.). 
   
   
       10 . The process of  claim 8  wherein the hydrotreating zone is operated at conditions including a temperature from about 204° C. (400° F.) to about 482° C. (900° F.) and a pressure from about 3.5 MPa (500 psig) to about 17.3 MPa (2500 psig). 
   
   
       11 . The process of  claim 8  wherein the recovery of the unconverted hydrocarbons boiling in the range of the hydrocarbonaceous feedstock is conducted in a high pressure product stripper. 
   
   
       12 . The process of  claim 8  wherein the ratio of the unconverted hydrocarbons boiling in the range of the hydrocarbonaceous feedstock recovered in step (b) to the hydrocarbonaceous feedstock is from about 1:5 to about 3:5. 
   
   
       13 . The process of  claim 8  wherein the recovery of the unconverted hydrocarbons boiling in the range of the hydrocarbonaceous feedstock is conducted in a fractionation zone. 
   
   
       14 . The process of  claim 8  wherein the hydrocracking zone is operated at conditions including a temperature from about 232° C. (450° F.) to about 468° C. (875° F.) and a pressure from about 3.5 MPa (500 psig) to about 17.3 MPa (2500 psig). 
   
   
       15 . A process for hydrocracking a hydrocarbonaceous feedstock which comprises:
 (a) introducing a liquid phase stream comprising a hydrocarbonaceous feed stock, a liquid phase effluent from a hydrocracking zone, and a sufficiently low hydrogen concentration to maintain a liquid phase continuous system into a hydrotreating zone to produce hydrogen sulfide and ammonia, and provide a first hydrocarbonaceous stream comprising hydrocarbons having a reduced level of sulfur and nitrogen;   (b) introducing the first hydrocarbonaceous stream comprising hydrocarbons having a reduced level of sulfur and nitrogen into a hydrocracking zone with a sufficiently low hydrogen concentration to maintain a liquid phase continuous system to produce a hydrocracking zone effluent;   (c) introducing the hydrocracking zone effluent into a separation zone to produce a second hydrocarbonaceous stream containing lower boiling hydrocarbons and a liquid phase hydrocarbonaceous stream comprising unconverted hydrocarbons;   (d) introducing the liquid phase hydrocarbonaceous stream comprising unconverted hydrocarbons recovered in step (c) into step (a), and;   (e) recovering hydrocracked hydrocarbons boiling at a temperature range lower than the hydrocarbonaceous feedstock.   
   
   
       16 . The process of  claim 15  wherein the hydrocarbonaceous feedstock boils in the range from about 315° C. (600° F.) to about 565° C. (1050° F.). 
   
   
       17 . The process of  claim 15  wherein the hydrotreating zone is operated at conditions including a temperature from about 204° C. (400° F.) to about 482° C. (900° F.) and a pressure from about 3.5 MPa (500 psig) to about 17.3 MPa (2500 psig). 
   
   
       18 . The process of  claim 15  wherein the separation zone is a high pressure product stripper. 
   
   
       19 . The process of  claim 15  wherein the ratio of the unconverted hydrocarbons boiling in the range of the hydrocarbonaceous feedstock recovered in step (c) to the hydrocarbonaceous feedstock is from about 1:5 to about 3:5. 
   
   
       20 . The process of  claim 15  wherein the hydrocracking zone is operated at conditions including a temperature from about 232° C. (450° F.) to about 468° C. (875° F.) and a pressure from about 3.5 MPa (500 psig) to about 17.3 MPa (2500 psig).