Process for maximizing the conversion of crude oils and/or condensates into valuable chemical products with flexibility to produce ultra-low sulfur diesel (ulsd)

Abstract

Systems and methods for flexibly converting crude oil to chemicals and fuels. The systems include unit operations configured to provide flexibility between operating in two different modes for two periods of time. A method includes separating a crude oil, distillate hydrotreating a medium oil fraction resulting from the separation, and operating in a max chemicals mode of operation for a first period of time and in a chemicals plus fuels mode for a second period of time. The method may further include conditioning and hydroprocessing, collectively separating, recovering an unconverted oil fraction, and feeding a light oil fraction, first hydrocarbon fraction, and a diesel fuel fraction or jet fuel fraction to a steam cracker. The system includes a separation unit, a low pressure distillate hydrotreating unit, a separation unit, a steam cracker unit, a separation system, a flow system, and a control system.

What is claimed as new and desired to be protected by Letters Patent is: 
     
         1 . A method for converting crude oil to chemicals and fuels, the method comprising:
 separating a crude oil into a light oil fraction, a medium oil fraction, and a heavy oil fraction;   distillate hydrotreating the medium oil fraction under low pressure conditions to produce a hydrotreated medium oil fraction;   operating in a max chemicals mode of operation for a first period of time and operating in a chemicals plus fuels mode of operation for a second period of time, the method comprising:   in the max chemicals mode of operation:
 feeding the light oil fraction to a steam cracker to crack hydrocarbons in the light oil to form a cracked light oil; 
 feeding an entirety of the hydrotreated medium oil fraction to the steam cracker to crack hydrocarbons in the hydrotreated medium oil fraction to form a cracked medium oil; 
 collectively separating the cracked light oil and the cracked medium oil to recover two or more hydrocarbon fractions, including a pyrolysis oil fraction; 
   in the chemicals plus fuels mode of operation:
 separating the hydrotreated medium oil fraction to recover a light hydrotreated fraction, a diesel fuel fraction, a jet fuel fraction, a heavy hydrotreated fraction, or combinations thereof; 
 mixing the light hydrotreated fraction with the light oil fraction to form a combined light oil fraction; 
 feeding the combined light oil fraction to the steam cracker to crack hydrocarbons in the combined light oil fraction to form a cracked combined light oil; 
 feeding the heavy hydrotreated fraction to the steam cracker to crack hydrocarbons in the heavy hydrotreated fraction to form a cracked medium oil; 
 collectively separating the cracked combined light oil and the cracked medium oil to recover two or more hydrocarbon fractions and a pyrolysis oil fraction. 
   
     
     
         2 . The method of  claim 1 , further comprising transitioning from the max chemicals mode to the chemicals plus fuels mode, wherein the transitioning comprises one or more of:
 decreasing a cut point temperature of the light oil fraction;   varying a cut point temperature of the heavy oil fraction;   varying a severity of the distillate hydrotreating to increase a conversion of hydrocarbons in the medium oil fraction to form diesel range hydrocarbons; and   starting up or increasing a feed rate of the hydrotreated medium oil fraction to a fractionation system configured for the separating of the hydrotreated medium oil fraction to recover a light hydrotreated fraction, a diesel fuel fraction, a jet fuel fraction, a heavy hydrotreated fraction, or combinations thereof.   
     
     
         3 . The method of  claim 1 , further comprising feeding a light hydrocarbon feedstock to the steam cracker for concurrent chemicals production along with the light oil fraction. 
     
     
         4 . The method of  claim 2 , wherein the transitioning from the max chemicals mode to the chemicals plus fuels mode further comprises one or more of:
 adjusting a feed rate of an external feed provided to the steam cracker;   adjusting a feed rate of a fuel supplied to the steam cracker;   adjusting a temperature of the steam cracker;   adjusting operating conditions of separators used in the collectively separating.   
     
     
         5 . The method of  claim 2 , further comprising transitioning from the chemicals plus fuels mode to the max chemicals mode, wherein the transitioning comprises one or more of:
 increasing a cut point temperature of the light oil fraction;   varying a cut point temperature of the heavy oil fraction;   varying a severity of the distillate hydrotreating to decrease a conversion of hydrocarbons in the medium oil fraction to form diesel range hydrocarbons; and   shutting down or decreasing a feed rate of the medium oil fraction to the fractionation system configured for the separating of the hydrotreated medium oil fraction to recover a light hydrotreated fraction, a diesel fuel fraction, a jet fuel fraction, a heavy hydrotreated fraction, or combinations thereof.   
     
     
         6 . The method of  claim 1 , wherein the heavy oil fraction is less than about 2 vol % of the crude oil, the method further comprising mixing the pyrolysis oil with the heavy oil fraction to recover a very low sulfur fuel oil. 
     
     
         7 . The method of  claim 1 , further comprising:
 conditioning and hydroprocessing, in a heavies conditioning unit, the pyrolysis oil and the heavy oil fraction to form one or more hydroprocessed fractions and a very low sulfur fuel oil fraction; and   feeding the one or more hydroprocessed fractions to the steam cracker to crack hydrocarbons contained in the one or more hydroprocessed fractions to recover one or more cracked hydroprocessed fractions.   
     
     
         8 . The method of  claim 7 , further comprising feeding a heavy hydrocarbon feedstock to the heavies conditioning unit for concurrent conditioning and hydroprocessing along with the heavy oil fraction. 
     
     
         9 . The method of  claim 7 , wherein transitioning between the max chemicals mode and the chemicals plus fuels modes of operations comprises one or more of:
 adjusting a feed rate of one or more external feeds provided to the heavies conditioning unit;   adjusting one or more operating conditions in the heavies conditioning unit;   adjusting a feed rate of an external feed provided to the steam cracker;   adjusting a feed rate of a fuel supplied to the steam cracker;   adjusting a temperature of the steam cracker;   adjusting operating conditions of separators used in the heavies conditioning unit; and   adjusting operating conditions of separators used in the collectively separating.   
     
     
         10 . The method of  claim 1 , wherein the separating the crude oil into the light oil fraction, the medium oil fraction, and the heavy oil fraction further comprises separating the crude oil into the light oil fraction and an intermediate fraction in a first separation unit, and separating the intermediate fraction into the medium oil fraction and the heavy oil fraction in a section separation unit. 
     
     
         11 . A system for converting crude oil to chemicals and fuels, the system comprising:
 a separation unit configured to separate a crude oil into a light oil fraction, a middle oil fraction, and a heavy oil fraction;   a low pressure distillate hydrotreating unit configured to hydrotreat the middle oil fraction, at mild conditions, to produce a hydrotreated middle oil fraction;   a separation unit configured to separate the hydrotreated middle oil fraction into a light hydrotreated fraction, a diesel fuel fraction, a jet fuel fraction, a heavy hydrotreated fraction, or combinations thereof;   a steam cracker unit configured to crack the light oil fraction, the light hydrotreated fraction, and the heavy hydrotreated fraction to produce cracked hydrocarbons;   a separation system configured to separate the cracked hydrocarbons into two or more hydrocarbon fractions and a pyrolysis oil fraction;   a flow system configured to:
 divert a portion or an entirety of the hydrotreated middle oil fraction to the steam cracker; or 
 provide an entirety or portion of the middle oil fraction to the separation system; 
   a control system configured to increase or decrease an amount of the diesel fuel fraction or jet fuel fraction, wherein the control system is configured to:
 control an amount of hydrotreated middle oil fraction fed to the steam cracker; 
 control an amount of hydrotreated middle oil fraction fed to the separation system; 
 control a cut point of the light oil fraction; 
 control a cut point of the heavy oil fraction; 
 control a severity of reaction conditions in the distillate hydrotreating. 
   
     
     
         12 . The system of  claim 11 , further comprising:
 a heavies conditioning unit configured to condition the pyrolysis oil and the heavy oil fraction to form one or more conditioned heavy fractions and a very low sulfur fuel oil fraction; and   a flow line for feeding the one or more conditioned heavy fractions to the steam cracker.   
     
     
         13 . The system of  claim 12 , further comprising a flow line for feeding one or more conditioned heavy fractions to the separation unit. 
     
     
         14 . The system of  claim 12 , further comprising a feed line for providing one or more additional light hydrocarbon feeds to the steam cracker unit. 
     
     
         15 . A process for converting crude oil to chemicals and fuels, the process comprising:
 separating a crude oil into a light oil fraction, a medium oil fraction, and a heavy oil fraction;   distillate hydrotreating the medium oil fraction under low pressure conditions to produce a hydrotreated medium oil fraction;   conditioning and hydroprocessing, in a heavies conditioning unit, a pyrolysis oil and the heavy oil fraction to form one or more hydroprocessed fractions and a very low sulfur fuel oil fraction;   collectively separating the one or more hydroprocessed fractions and the hydrotreated medium oil fraction to recover three or more hydrocarbon fractions, including a first hydrocarbon fraction, a diesel fuel fraction, a jet fuel fraction, an unconverted oil fraction, or combinations thereof;   recovering the unconverted oil fraction as at least a portion of the very low sulfur fuel oil;   feeding the light oil fraction, the first hydrocarbon fraction, and a portion or an entirety of the diesel fuel fraction or jet fuel fraction to a steam cracker to crack hydrocarbons in the respective fractions;   operating in a max chemicals mode of operation for a first period of time and operating in a chemicals plus fuels mode of operation for a second period of time, the process comprising:   in the max chemicals mode of operation:
 feeding an entirety of the diesel fuel fraction or jet fuel fraction to the steam cracker to crack hydrocarbons in the diesel fuel fraction or jet fuel fraction to form a cracked fuel effluent; and 
 collectively separating the cracked hydrocarbons from the respective fractions to recover two or more hydrocarbon fractions, including the pyrolysis oil fraction; 
   in the chemicals plus fuels mode of operation:
 recovering a portion of the diesel fuel fraction or jet fuel fraction as a fuel product; and 
 collectively separating the cracked hydrocarbons to recover two or more hydrocarbon fractions, including the pyrolysis oil fraction. 
   
     
     
         16 . The process of  claim 15 , further comprising transitioning from the max chemicals mode to the chemicals plus fuels mode, wherein the transitioning comprises one or more of:
 adjusting a cut point temperature of the light oil fraction;   adjusting a cut point temperature of the heavy oil fraction;   varying a severity of the distillate hydrotreating to increase a conversion of hydrocarbons in the medium oil fraction to form diesel range hydrocarbons; and   varying a severity of the conditioning and hydroprocessing to increase a conversion of the heavy oil fraction and the pyrolysis oil to form diesel range hydrocarbons.   
     
     
         17 . The process of  claim 15 , further comprising transitioning from the chemicals plus fuels mode to the max chemicals mode, wherein the transitioning comprises one or more of:
 adjusting a cut point temperature of the light oil fraction   adjusting a cut point temperature of the heavy oil fraction;   varying a severity of the distillate hydrotreating to decrease a conversion of hydrocarbons in the medium oil fraction to form diesel range hydrocarbons; and   varying a severity of the conditioning and hydroprocessing to decrease a conversion of the heavy oil fraction and the pyrolysis oil to form diesel range hydrocarbons.   
     
     
         18 . The process of  claim 16 , further comprising feeding a light hydrocarbon feedstock to the steam cracker for concurrent chemicals production along with the light oil fraction. 
     
     
         19 . The process of  claim 16 , further comprising feeding a heavy hydrocarbon feedstock to the heavies conditioning unit for concurrent conditioning and hydroprocessing along with the heavy oil fraction.