Process for maximizing production of heavy naphtha from a hydrocarbon stream

Abstract

Processes and apparatus for maximizing production of heavy naphtha from a hydrocarbon stream are provided. The process comprises providing a hydrocarbon feed stream comprising vacuum gas oil to a first hydrocracking reactor. The hydrocarbon feed stream is hydrocracked at first hydrocracking conditions comprising a first hydrocracking pressure to provide a first hydrocracked effluent stream therein. At least a portion of the first hydrocracked effluent stream is fractionated in a fractionation column to provide a heavy naphtha fraction. A kerosene stream is hydrocracked in a second hydrocracking reactor operating at second hydrocracking conditions comprising a second hydrocracking pressure to provide a second hydrocracked effluent stream. In an aspect, the first hydrocracking pressure can be greater than the second hydrocracking pressure by at least about 6895 kPa (g). At least a portion of the second hydrocracked effluent stream is passed to the fractionation column to maximize the production of heavy naphtha.

1 . A process for maximizing production of heavy naphtha from a hydrocarbon stream comprising:
 a) providing a hydrocarbon feed stream comprising vacuum gas oil to a first hydrocracking reactor;   b) hydrocracking the hydrocarbon feed stream in the presence of a hydrogen stream and a first hydrocracking catalyst in the first hydrocracking reactor at first hydrocracking conditions comprising a first hydrocracking pressure to provide a first hydrocracked effluent stream;   c) fractionating at least a portion of the first hydrocracked effluent stream in a fractionation column to provide a heavy naphtha fraction, a kerosene fraction, and a diesel fraction;   d) hydrocracking a kerosene stream in a second hydrocracking reactor operating at second hydrocracking conditions comprising a second hydrocracking pressure to provide a second hydrocracked effluent stream, the first hydrocracking pressure being greater than the second hydrocracking pressure by at least about 6895 kPa(g) (1000 psig); and   e) passing at least a portion of the second hydrocracked effluent stream to the fractionation column to maximize the production of heavy naphtha.   
     
     
         2 . The process of  claim 1 , wherein the first hydrocracking pressure is greater than the second hydrocracking pressure by at least about 7240 kPa(g) (1050 psig). 
     
     
         3 . The process of  claim 1 , wherein the kerosene stream to the second hydrocracking reactor comprises a portion of the kerosene fraction from the fractionation column. 
     
     
         4 . The process of  claim 1 , wherein the kerosene stream to the second hydrocracking reactor comprises a kerosene fraction from an external source. 
     
     
         5 . The process of  claim 1  further comprising passing the hydrocarbon feed stream through a hydrotreating reactor before being passed to the first hydrocracking reactor. 
     
     
         6 . The process of  claim 1  further comprising passing at least a portion of the first hydrocracked effluent stream to a first separator to provide a first vaporous stream and a first liquid stream and passing at least a portion of the first liquid stream to the fractionation column. 
     
     
         7 . The process of  claim 1  further comprising passing the second hydrocracked effluent stream to a second separator to provide a second vaporous stream and a second liquid stream and passing at least a portion of the second liquid stream to the fractionation column. 
     
     
         8 . The process of  claim 1 , wherein the at least a portion of the first hydrocracked effluent stream and the at least a portion of the stripped second hydrocracked effluent stream are passed to a common stripper before being passed to the fractionation column. 
     
     
         9 . The process of  claim 1  further comprising compressing a make-up hydrogen stream in at least two-stage compressor and a portion of a compressed make-up hydrogen stream is withdrawn upstream from a second compressor of the at least two-stage compressor and passed to the second hydrocracking reactor. 
     
     
         10 . The process of  claim 9 , wherein a remaining portion of the compressed make-up hydrogen stream is further compressed in the at least two-stage compressor and passed to the first hydrocracking reactor. 
     
     
         11 . The process of  claim 1 , further comprising at least one of:
 sensing at least one parameter of the process for maximizing production of heavy naphtha and generating a signal or data from the sensing;   generating and transmitting a signal; or   generating and transmitting data.   
     
     
         12 . A process for maximizing production of heavy naphtha from a hydrocarbon stream comprising:
 a) providing a hydrocarbon feed stream comprising vacuum gas oil to a first hydrocracking reactor;   b) hydrocracking the hydrocarbon feed stream in the presence of a hydrogen stream and a first hydrocracking catalyst in the first hydrocracking reactor operating at first hydrocracking conditions comprising a first hydrocracking pressure to provide a first hydrocracked effluent stream;   c) passing at least a portion of the first hydrocracked effluent stream to a first separator to provide a first vaporous stream and a first liquid stream;   d) fractionating at least a portion of the first liquid stream in a fractionation column to provide a heavy naphtha fraction, a kerosene fraction, and a diesel fraction;   e) hydrocracking a kerosene stream in a second hydrocracking reactor operating at second hydrocracking conditions comprising a second hydrocracking pressure to provide a second hydrocracked effluent stream, the first hydrocracking pressure being greater than the second hydrocracking pressure by at least about 6895 kPa(g) (1000 psig);   f) passing the second hydrocracked effluent stream to a second separator to provide a second vaporous stream and a second liquid stream;   g) passing the entire second vaporous stream to the second hydrocracking reactor; and   h) passing at least a portion of the second liquid stream to the fractionation column to maximize the production of heavy naphtha.   
     
     
         13 . The process of  claim 12 , wherein the first hydrocracking pressure is from about 13790 kPa(g) (2000 psig) to about 17237 kPa(g) (2500 psig) and the second hydrocracking pressure is from about 2758 kPa(g) (400 psig) to about 6550 kPa(g) (950 psig). 
     
     
         14 . The process of  claim 12 , wherein the first liquid stream and the second liquid stream are passed to a common stripper before being passed to the fractionation column. 
     
     
         15 . The process of  claim 12 , wherein the kerosene stream to the second hydrocracking reactor comprises a portion of the kerosene fraction from the fractionation column. 
     
     
         16 . The process of  claim 12 , wherein the kerosene stream to the second hydrocracking reactor comprises a kerosene fraction from an external source. 
     
     
         17 . A process for maximizing production of heavy naphtha from a hydrocarbon stream comprising:
 a) providing a hydrocarbon feed stream comprising vacuum gas oil to a first hydrocracking reactor;   b) hydrocracking the hydrocarbon feed stream in the presence of a hydrogen stream and a first hydrocracking catalyst in the first hydrocracking reactor operating at first hydrocracking conditions comprising a first hydrocracking pressure to provide a first hydrocracked effluent stream;   c) fractionating at least a portion of the first hydrocracked effluent stream in a fractionation column to provide a heavy naphtha fraction, a kerosene fraction, and a diesel fraction;   d) compressing a make-up hydrogen stream in at least two-stage compressor and a portion of a compressed make-up hydrogen gas stream is withdrawn upstream from a second compressor of the at least two-stage compressor;   e) compressing the remaining portion of the make-up hydrogen gas stream further in the at least two-stage compressor and passed to the first hydrocracking reactor as the hydrogen stream;   f) hydrocracking a kerosene stream in the presence of the portion of the compressed hydrogen gas to a second hydrocracking reactor operating at second hydrocracking conditions comprising a second hydrocracking pressure of to provide a second hydrocracked effluent stream predominantly comprising naphtha, the first hydrocracking pressure being greater than the second hydrocracking pressure by at least about 6895 kPa(g) (1000 psig); and   g) passing at least a portion of the second hydrocracked effluent stream to the fractionation column to maximize the production of heavy naphtha.   
     
     
         18 . The process of  claim 17 , wherein the first hydrocracking pressure is from about 13790 kPa(g) (2000 psig) to about 17237 kPa(g) (2500 psig) and the second hydrocracking pressure is from about 2758 kPa(g) (400 psig) to about 6550 kPa(g) (950 psig). 
     
     
         19 . The process of  claim 17 , wherein the kerosene stream to the second hydrocracking reactor comprises a portion of the kerosene fraction from the fractionation column. 
     
     
         20 . The process of  claim 17 , wherein the kerosene stream to the second hydrocracking reactor comprises a kerosene fraction from an external source.