Method to valorize middle distillate streams from crude oils

Abstract

Systems and methods are provided to evaluate a middle distillate sample by determining the hydrogen partial pressure requirements in a reactor under design for processing a feedstock consisting of the middle distillate sample to achieve a target sulfur concentration of a target product stream and/or the cetane number in the target product stream.

What is claimed is: 
     
         1 . A method for evaluating a middle distillate sample comprising:
 analyzing the middle distillate sample to determine a sample sulfur concentration;   optionally analyzing the middle distillate sample to determine a sample cetane number;   providing a target sulfur concentration of a target product stream from a reactor under design for hydrodesulfurization of a feedstock consisting of the middle distillate sample, the reactor under design including defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio;   calculating a sulfur conversion to achieve the target sulfur concentration of the target product stream, as a function of the sample sulfur concentration and the target sulfur concentration, by dividing the difference in sulfur concentration of the middle distillate sample and the target product stream by the sulfur concentration of the middle distillate sample;   determining a sample requisite hydrogen partial pressure in the reactor under design, as a function of the sulfur conversion, wherein the sample requisite hydrogen partial pressure is determined experimentally or by simulation; and   calculating a severity index, as a function of the sample requisite hydrogen partial pressure, by dividing the requisite hydrogen partial pressure by a reference hydrogen partial pressure, wherein the reference hydrogen partial pressure is a required hydrogen partial pressure for hydrodesulfurization of a feedstock consisting of a reference middle distillate to achieve approximately the target sulfur concentration with approximately the defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio.   
     
     
         2 . The method of  claim 1 , wherein the sample requisite hydrogen partial pressure is determined by simulation and wherein the process comprises analyzing the middle distillate sample to determine a sample cetane number. 
     
     
         3 . The method of  claim 1 , further comprising providing a computer comprising a processor coupled to a non-volatile memory, wherein the non-volatile memory stores calculation modules and data, and entering into the computer data including the sample sulfur concentration and optionally the sample cetane number. 
     
     
         4 . The method of  claim 1 , further comprising:
 calculating a relative cost to process the feedstock consisting of the middle distillate sample by the following equation:   C2=C1*SI n , where C1 is the cost to process the reference feedstock, C2 is the projected cost to process the feedstock consisting of the middle distillate sample, and n is a number in the range of about 0.6-0.8.   
     
     
         5 . The method of  claim 1 , further comprising calculating a plurality of severity indices corresponding to a plurality of middle distillate samples to produce a database of severity indices, wherein the severity index of each of the middle distillate samples in the plurality of middle distillate samples is calculated as a function of the sample requisite hydrogen partial pressure, by dividing a requisite hydrogen partial pressure by a reference hydrogen partial pressure, wherein the reference hydrogen partial pressure is a required hydrogen partial pressure for hydrodesulfurization of a feedstock consisting of a reference middle distillate to achieve approximately the target sulfur concentration with approximately the defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio,
 wherein the requisite hydrogen partial pressure of each of the middle distillate samples in the plurality of middle distillate samples is determined as a function of a sulfur conversion, wherein the sample requisite hydrogen partial pressure is determined experimentally or by simulation.   
     
     
         6 . The method of  claim 5 , wherein a ranking value for the middle distillate sample is assigned by comparing the severity index value for the middle distillate sample and the database of severity indices. 
     
     
         7 . A method for evaluating a middle distillate sample comprising:
 analyzing the middle distillate sample to determine a sample cetane number;   optionally analyzing the middle distillate sample to determine a sample sulfur concentration;   providing a target cetane number of a target product stream from a reactor under design for hydrotreatment of a feedstock consisting of the middle distillate sample, the reactor under design including defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio;   calculating a cetane number improvement to achieve the target cetane number of the target product stream, as a function of the sample cetane number and the target cetane number, by taking the cetane number of the target product stream and subtracting the cetane number of the middle distillate sample;   determining a sample requisite hydrogen partial pressure in the reactor under design, as a function of the cetane number improvement, wherein the sample requisite hydrogen partial pressure is determined experimentally or by simulation; and   calculating a severity index, as a function of the sample requisite hydrogen partial pressure, by dividing the requisite hydrogen partial pressure by a reference hydrogen partial pressure, wherein the reference hydrogen partial pressure is a required hydrogen partial pressure for hydrotreatment of a feedstock consisting of a reference middle distillate to achieve approximately the target cetane number with approximately the defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio.   
     
     
         8 . The method of  claim 7 , wherein the sample requisite hydrogen partial pressure is determined by simulation and wherein the process comprises analyzing the middle distillate sample to determine a sample sulfur concentration. 
     
     
         9 . The method of  claim 7 , further comprising providing a computer comprising a processor coupled to a non-volatile memory, wherein the non-volatile memory stores calculation modules and data, and entering into the computer data including the sample cetane number and optionally the sample sulfur concentration. 
     
     
         10 . The method of  claim 7 , further comprising:
 calculating a relative cost to process the feedstock consisting of the middle distillate sample by the following equation:   C2=C1*SI n , where C1 is the cost to process the reference feedstock, C2 is the projected cost to process the feedstock consisting of the middle distillate sample, and n is a number in the range of about 0.6-0.8.   
     
     
         11 . The method of  claim 7 , further comprising calculating a plurality of severity indices corresponding to a plurality of middle distillate samples to produce a database of severity indices, wherein the severity index of each of the middle distillate samples in the plurality of middle distillate samples is calculated as a function of the sample requisite hydrogen partial pressure, by dividing a requisite hydrogen partial pressure by a reference hydrogen partial pressure, wherein the reference hydrogen partial pressure is a required hydrogen partial pressure for hydrotreatment of a feedstock consisting of a reference middle distillate to achieve approximately the target cetane number with approximately the defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio,
 wherein the requisite hydrogen partial pressure of each of the middle distillate samples in the plurality of middle distillate samples is determined as a function of a cetane number improvement, wherein the sample requisite hydrogen partial pressure is determined experimentally or by simulation.   
     
     
         12 . The method of  claim 11 , wherein a ranking value for the middle distillate sample is assigned by comparing the severity index value for the middle distillate sample and the database of severity indices. 
     
     
         13 . The method of  claim 7 , wherein the hydrotreating process is hydrogenation, hydrocracking, or both. 
     
     
         14 . A method for evaluating a middle distillate sample comprising:
 analyzing the middle distillate sample to determine a sample sulfur concentration and a sample cetane number;   providing a target sulfur concentration and target cetane number of a target product stream from a reactor under design for hydrodesulfurization and hydrotreatment of a feedstock consisting of the middle distillate sample, the reactor under design including defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio;   calculating a sulfur conversion to achieve the sulfur concentration of the target product stream, as a function of the sample sulfur concentration and the target sulfur concentration, by dividing the difference in sulfur concentration of the middle distillate sample and the target product stream by the sulfur concentration of the middle distillate sample;   calculating a cetane number improvement to achieve the target cetane number of the target product stream, as a function of the sample cetane number and the target cetane number, by taking the cetane number of the target product stream and subtracting the cetane number of the middle distillate sample;   determining a sample requisite hydrogen partial pressure in the reactor under design, as a function of the sulfur conversion and the cetane number improvement, wherein the sample requisite hydrogen partial pressure is determined experimentally or by simulation; and   calculating a severity index, as a function of the sample requisite hydrogen partial pressure, by dividing the requisite hydrogen partial pressure by a reference hydrogen partial pressure, wherein the reference hydrogen partial pressure is a required hydrogen partial pressure for hydrotreatment and hydrodesulfurization of a feedstock consisting of a reference middle distillate to achieve approximately the target sulfur concentration and target cetane number with approximately the defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio.   
     
     
         15 . The method of  claim 14 , wherein the sample requisite hydrogen partial pressure is determined by simulation. 
     
     
         16 . The method of  claim 14 , further comprising providing a computer comprising a processor coupled to a non-volatile memory, wherein the non-volatile memory stores calculation modules and data, and entering into the computer data including the sample cetane number and the sample sulfur concentration. 
     
     
         17 . The method of  claim 14 , further comprising:
 calculating a relative cost to process the feedstock consisting of the middle distillate sample by the following equation:   C2=C1*SI n , where C1 is the cost to process the reference feedstock, C2 is the projected cost to process the feedstock consisting of the middle distillate sample, and n is a number in the range of about 0.6-0.8.   
     
     
         18 . The method of  claim 14 , further comprising calculating a plurality of severity indices corresponding to a plurality of middle distillate samples to produce a database of severity indices, wherein the severity index of each of the middle distillate samples in the plurality of middle distillate samples is calculated as a function of the sample requisite hydrogen partial pressure, by dividing a requisite hydrogen partial pressure by a reference hydrogen partial pressure, wherein the reference hydrogen partial pressure is a required hydrogen partial pressure for hydrodesulfurization and hydrotreatment of a feedstock consisting of a reference middle distillate to achieve approximately the target sulfur concentration and target cetane number with approximately the defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio,
 wherein the requisite hydrogen partial pressure of each of the middle distillate samples in the plurality of middle distillate samples is determined as a function of a sulfur conversion and a cetane number improvement, wherein the sample requisite hydrogen partial pressure is determined experimentally or by simulation.   
     
     
         19 . The method of  claim 18 , wherein a ranking value for the middle distillate sample is assigned by comparing the severity index value for the middle distillate sample and the database of severity indices. 
     
     
         20 . The method as in  claim 1 , wherein a crude oil is fractionated into one or more streams, wherein the middle distillate sample is one of the streams.