METHOD TO VALORIZE MIDDLE DISTILLATE STREAMS FROM CRUDE OILS

Description

FIELD OF THE DISCLOSURE

The present disclosure relates to methods of evaluating middle distillate samples.

BACKGROUND OF THE DISCLOSURE

In a refinery, crude oil is typically fractionated into one or more fractions such as light gases, light naphtha streams, heavy naphtha streams, middle distillates, vacuum gas oil, and vacuum residue fraction. The middle distillates from the crude oil distillation include fractions such as gas oils and can be blended into diesel fuels, jet fuels and/or furnace oils, directly or following hydrotreating to obtain ultra-low sulfur diesel. Several properties of gas oil and diesel streams can be evaluated, including API gravity, sulfur, nitrogen, carbon and hydrogen contents, and cetane number. For diesel engines, the fuel must have characteristics that favor auto-ignition. The ignition delay period can be evaluated by the fuel characterization factor called cetane number (CN). The behavior of a diesel fuel is measured by comparing its performance with two pure hydrocarbons: the first is n-cetane or n-hexadecane (n-C₁₆H₃₄) which has a cetane number 100, and the second is α-methylnaphthalene which has a cetane number of 0. As an example, a diesel fuel has a cetane number of 60 if it behaves like a binary mixture of 60 vol % n-cetane or n-hexadecane and 40 vol % α-methylnaphthalene. Sometimes in practice, heptamethylnonane (HMN) is used instead of α-methylnaphthalene. HMN is a branched isomer of n-cetane and has a cetane number of 15. Therefore, in practice the cetane number can be defined as:

CN = vol ⁢ % ⁢ ( n - cetane ) + 0.15 * vol ⁢ % ⁢ ( HMN ) . ( 1 )

The cetane number of a diesel fuel can be measured in a laboratory by various test methods, for example, the ASTM D613 test method. The shorter the ignition delay period a diesel fuel has, the higher its cetane value is. Higher cetane number fuels reduce combustion noise and permit improved control of combustion resulting in increased engine efficiency and power output. Higher cetane number fuels help with easier starting and faster warm-up in cold weather and can also help reduce air pollution.

It is very difficult to evaluate the diesel streams based on their hydrocarbon distributions. Rather, all the diesel fractions must be brought to a commercial product stream for evaluation purposes. In regard to the above background information, the present disclosure is directed to provide a technical solution for effective methods and systems for evaluating middle distillates.

SUMMARY OF THE DISCLOSURE

In certain embodiments, a method for evaluating a middle distillate sample is provided. The method comprises analyzing the middle distillate sample to determine a sample sulfur concentration. The middle distillate sample can optionally be analyzed to also determine a sample cetane number. 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 is provided. The reactor under design can include a defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio. A sulfur conversion to achieve the target sulfur concentration of the target product stream is calculated as a function of the sample sulfur concentration and the target sulfur concentration. This can be done 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. A sample requisite hydrogen partial pressure in the reactor under design is determined as a function of the sulfur conversion, wherein the sample requisite hydrogen partial pressure is determined experimentally or by simulation. A severity index is calculated as a function of the sample requisite hydrogen partial pressure. This can be done 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.

In some embodiments, the sample requisite hydrogen partial pressure is determined by simulation. In these embodiments, the process includes the step of analyzing the middle distillate sample to determine a sample cetane number.

In some embodiments, the process also includes providing a computer comprising a processor coupled to a non-volatile memory, wherein the non-volatile memory stores calculation modules and data. Data including the sample sulfur concentration and optionally the sample cetane number is entered into the computer.

In certain embodiments, a method for evaluating a middle distillate sample is provided. The method comprises analyzing the middle distillate sample to determine a sample cetane number. The middle distillate sample can optionally be analyzed to also determine a sample sulfur concentration. 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 is provided. The reactor under design can include a defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio. A cetane number improvement to achieve the target cetane number of the target product stream is calculated as a function of the sample cetane number and the target cetane number. This can be done by taking the cetane number of the target product stream and subtracting the cetane number of the middle distillate sample. A sample requisite hydrogen partial pressure in the reactor under design is determined as a function of the cetane number improvement, wherein the sample requisite hydrogen partial pressure is determined experimentally or by simulation. A severity index is calculated as a function of the sample requisite hydrogen partial pressure. This can be done 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.

In some embodiments, the sample requisite hydrogen partial pressure is determined by simulation. In these embodiments, the process includes analyzing the middle distillate sample to determine a sample sulfur concentration.

In some embodiments, the process also includes providing a computer comprising a processor coupled to a non-volatile memory, wherein the non-volatile memory stores calculation modules and data. Data including the sample cetane number and optionally the sample sulfur concentration is entered into the computer.

In certain embodiments, a method for evaluating a middle distillate sample is provided. The method comprises analyzing the middle distillate sample to determine a sample sulfur concentration and a sample cetane number. 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 is provided. The reactor under design can include a defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio. A sulfur conversion to achieve the target sulfur concentration of the target product stream is calculated as a function of the sample sulfur concentration and the target sulfur concentration. This can be done 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. A cetane number improvement to achieve the target cetane number of the target product stream is calculated as a function of the sample cetane number and the target cetane number. This can be done by taking the cetane number of the target product stream and subtracting the cetane number of the middle distillate sample. A sample requisite hydrogen partial pressure in the reactor under design is determined as a function of the sulfur conversion and cetane number improvement, wherein the sample requisite hydrogen partial pressure is determined experimentally or by simulation. A severity index is calculated as a function of the sample requisite hydrogen partial pressure. This can be done 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 and target cetane number with approximately the defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio.

In some embodiments, the sample requisite hydrogen partial pressure is determined by simulation.

In some embodiments, the process also includes providing a computer comprising a processor coupled to a non-volatile memory, wherein the non-volatile memory stores calculation modules and data. Data including the sample cetane number and the sample sulfur concentration is entered into the computer.

In some embodiments the hydrotreating process is hydrogenation, hydrocracking, or both.

In some embodiments, the sulfur conversion is calculated by the following equation (as a fraction conversion, where a weight percent conversion is calculated by multiplying the below quotient by 100):

Conversion Sulfur = Sulfur sample - Sulfur target Sulfur sample . ( 2 )

In some embodiments, the cetane number improvement (point value improvement) is calculated by the following equation:

Cetane ⁢ number ⁢ improvement = Cetane ⁢ number product - Cetane ⁢ number sample . ( 3 )

In some embodiments, the severity index of the middle distillate sample is calculated with the following equation:

SI = hydrogen ⁢ partial ⁢ pressure sample hydrogen ⁢ partial ⁢ pressure reference . ( 4 )

In some embodiments, the process also includes calculating a relative cost to process the feedstock consisting of the middle distillate sample by the following equation:

C ⁢ 2 = C ⁢ 1 * SI n , ( 5 )

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.

In some embodiments, the process also includes calculating a plurality of severity indices corresponding to a plurality of middle distillate samples to produce a database of severity indices. In these embodiments, 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. This can be done 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, hydrotreatment or both hydrodesulfurization and hydrotreatment of a feedstock consisting of a reference middle distillate to achieve approximately the target sulfur concentration, target cetane number or both the target sulfur concentration and cetane number with approximately the defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio. In these embodiments, 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, a cetane number improvement or both a sulfur conversion and a cetane conversion. The sample requisite hydrogen partial pressure can be determined experimentally or by simulation.

In some embodiments, 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.

In some embodiments, the middle distillate sample has a sulfur content in the range of about 100-50,000 ppmw sulfur.

In some embodiments, the target sulfur content of the target product stream is in the range of about 10-1,000 ppmw.

In some embodiments, the middle distillate feedstock has a boiling range in the range of about 150° C. to 400° C.

In some embodiments, a crude oil is fractionated into one or more streams, wherein the middle distillate sample is one of the streams. In some embodiments, the one or more streams further includes one or more of light gases, a light naphtha stream, a heavy naphtha stream, a vacuum gas oil, and a vacuum residue fraction. In some embodiments, the fractionation is by atmospheric distillation, vacuum distillation, or both.

In some embodiments, the plurality of middle distillate samples is obtained from fractionating a plurality of crude oils. In some embodiments, the plurality of crude oils is from one or more sources of crude oil.

Any combinations of the various embodiments and implementations disclosed herein can be used. These and other aspects and features can be appreciated from the following description of certain embodiments and the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a process flowchart of a method of one or more embodiments of the invention.

FIG. 1B is a process flowchart of an analysis step of a method of one or more embodiments of the invention.

FIG. 2 is a schematic block diagram of modules in accordance with an embodiment of the present invention where the reactor under design is a reactor for hydrodesulfurization.

FIG. 3 is a schematic block diagram of modules in accordance with an embodiment of the present invention where the reactor under design is a reactor for hydrotreatment.

FIG. 4 is a schematic block diagram of modules in accordance with an embodiment of the present invention where the reactor under design is a reactor for hydrodesulfurization and hydrotreatment.

FIG. 5 is a schematic block diagram of a computer system of one or more embodiments of the invention.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THE DISCLOSURE

The present disclosure provides a system and method that can compare plural middle distillate streams to determine rank valuation to give the refiner a basis for determining which stream may be processed first. Also, present disclosure provides a system and method for evaluation of middle distillate streams derived from crude oils from various sources to establish an objective basis for comparison. Systems and methods herein 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 and/or cetane number in a target product stream.

In certain embodiments, the term “middle distillate” is used with reference to one or more fractions containing hydrocarbons having a nominal boiling range of about 160-400, 160-380, 160-370, 160-360, 160-340, 170-400, 170-380, 170-370, 170-360, 170-340, 180-400, 180-380, 180-370, 180-360, 180-340, 190-400, 190-380, 190-370, 190-360, 190-340, 193-400, 193-380, 193-370, 193-360, or 193-340° C. In certain embodiments, the term “straight run middle distillate” is used with reference to one or more straight run fractions from the atmospheric distillation unit. In embodiments in which other terminology is used herein, the middle distillate fraction can also include all or a portion of atmospheric gas oil range hydrocarbons, all or a portion of kerosene, all or a portion of medium atmospheric gas oil range hydrocarbons, and/or all or a portion of heavy kerosene range hydrocarbons. The term “atmospheric gas oil” and its acronym “AGO” as used herein refer to hydrocarbons having a nominal boiling range of about 250-400, 250-380, 250-370, 250-360, 250-340, 250-320, 260-400, 260-380, 260-370, 260-360, 260-340, 260-320, 270-400, 270-380, 270-370, 270-360, 270-340 or 270-320° C. The term “kerosene” as used herein refers to hydrocarbons having a nominal boiling range of about 160-280, 160-270, 160-260, 170-280, 170-270, 170-260, 180-280, 180-270, 180-260, 190-280, 190-270, 190-260, 193-280, 193-270 or 193-260° C. The term “heavy kerosene” as used herein refers to hydrocarbons having a nominal boiling range of about 225-280, 225-270, 225-260, 230-280, 230-270, 230-260, 235-280, 235-270, 235-260 or 250-280° C. In additional embodiments, term “middle distillate” is used to refer to fractions from one or more integrated operations boiling in this range.

FIG. 1A shows a process flowchart of a method of one or more embodiments. A middle distillate sample is analyzed in step 110. In some embodiments, the sample is analyzed according to any known test methods to determine the sulfur content of the sample and/or the cetane number of the sample.

In step 120, one or more properties of a target product stream from a reactor under design for hydrodesulfurization and/or hydrotreatment of a feedstock consisting of the middle distillate sample is provided. The reactor under design can include a defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio. In some embodiments, the property of the target product stream is target sulfur concentration, target cetane number, or both. In some embodiments, the hydrotreating reaction is hydrogenation, hydrocracking, or both. In step 130, a conversion and/or improvement value is calculated.

In some embodiments, the conversion and/or improvement value calculated in step 130 is the sulfur conversion that is required to achieve the target sulfur concentration of the target product stream. The sulfur conversion is calculated as a function of the sample sulfur concentration and the target sulfur concentration, specifically, 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. The sulfur conversion can be calculated by the following equation (as a fraction conversion, where a weight percent conversion is calculated by multiplying the below quotient by 100):

Conversion Sulfur = Sulfur sample - Sulfur target Sulfur sample . ( 2 )

In some embodiments, the conversion and/or improvement value calculated in step 130 is the cetane number improvement that is required 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. The cetane number improvement (point value improvement) can be calculated by the following equation:

Cetane ⁢ number ⁢ improvement = Cetane ⁢ number product - Cetane ⁢ number sample . ( 3 )

In step 140, the hydrogen partial pressure that is required for the hydrodesulfurization and/or hydrotreating reaction of the middle distillate sample to achieve the required sulfur concentration and/or cetane number is determined. This determination can be done experimentally or by simulation.

In some embodiments where the determination of the requisite hydrogen partial pressure is done experimentally, in step 110, the sample is analyzed to determine the sulfur concentration of the sample and optionally the cetane number. In some embodiments where the determination of the requisite hydrogen partial pressure is done experimentally, in step 110, the sample is analyzed to determine the cetane number of the sample and optionally the sulfur concentration.

In some embodiments where the determination of the requisite hydrogen partial pressure is done by simulation, in step 110, the sample is analyzed to determine the sulfur content and the cetane number.

In step 150, a severity index is calculated as a function of the sample requisite hydrogen partial pressure, by dividing the requisite hydrogen partial pressure by a reference hydrogen partial pressure. The reference hydrogen partial pressure is a required hydrogen partial pressure for hydrodesulfurization and/or hydrotreatment of a feedstock containing a reference middle distillate to achieve approximately the target sulfur concentration and/or cetane number with approximately the defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio. In some embodiments, the severity index can be calculated by the following equation:

SI = hydrogen ⁢ partial ⁢ pressure sample hydrogen ⁢ partial ⁢ pressure reference . ( 4 )

In step 160, the relative cost to process a feedstock containing the middle distillate sample is calculated by the following equation:

C ⁢ 2 = C ⁢ 1 * SI n , ( 5 )

where C1 is the cost to process the reference feedstock, C2 is the relative cost to process the middle distillate feedstock, and n is a number in the range of about 0.6-0.8.

FIG. 1B is a flowchart showing details about the middle distillates analysis step 110, as described in FIG. 1A. In some embodiments, a feed such as crude oil 10 is separated in unit 20 into one or more streams including middle distillates stream 28. Optional streams 22, 24, 26, 30 and 32 can also be separated from crude oil 10. Stream 22 can include light gases like C2-C4 hydrocarbons such as ethane, propane and butanes. Stream 24 is a naphtha stream and stream 26 is a heavy naphtha stream. Stream 30 includes vacuum gas oil and stream 32 is a vacuum residue fraction. Separation unit 20 can be any known separation unit and can include an atmospheric distillation unit and a vacuum distillation unit. The feed 10 can be crude oil, or the feed can be crude oil that has been subjected to hydrotreating (hydrotreated crude oil), solvent deasphalting (deasphalted oil) or coking, such as delayed coking (coker liquid and gas products).

A middle distillate sample obtained from the middle distillates stream 28 is analyzed according to the process herein, represented as step 40. It is to be appreciated that the middle distillate characteristics are determined by the source and characteristics of the crude oil 10.

In certain embodiments, a method for evaluating a middle distillate sample is provided. The method comprises analyzing the middle distillate sample to determine a sample sulfur concentration. The middle distillate sample can optionally be analyzed to also determine a sample cetane number. 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 is provided. The reactor under design can include a defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio. A sulfur conversion to achieve the target sulfur concentration of the target product stream is calculated as a function of the sample sulfur concentration and the target sulfur concentration. This can be done 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. A sample requisite hydrogen partial pressure in the reactor under design is determined as a function of the sulfur conversion, wherein the sample requisite hydrogen partial pressure is determined experimentally or by simulation. A severity index is calculated as a function of the sample requisite hydrogen partial pressure. This can be done 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.

In some embodiments, the sample requisite hydrogen partial pressure is determined by simulation. In these embodiments, the process includes the step of analyzing the middle distillate sample to determine a sample cetane number.

In some embodiments, the process also includes providing a computer comprising a processor coupled to a non-volatile memory, wherein the non-volatile memory stores calculation modules and data. Data including the sample sulfur concentration and optionally the sample cetane number is entered into the computer.

In certain embodiments, a method for evaluating a middle distillate sample is provided. The method comprises analyzing the middle distillate sample to determine a sample cetane number. The middle distillate sample can optionally be analyzed to also determine a sample sulfur concentration. 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 is provided. The reactor under design can include a defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio. A cetane number improvement to achieve the target cetane number of the target product stream is calculated as a function of the sample cetane number and the target cetane number. This can be done by taking the cetane number of the target product stream and subtracting the cetane number of the middle distillate sample. A sample requisite hydrogen partial pressure in the reactor under design is determined as a function of the cetane number improvement, wherein the sample requisite hydrogen partial pressure is determined experimentally or by simulation. A severity index is calculated as a function of the sample requisite hydrogen partial pressure. This can be done 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.

In some embodiments, the sample requisite hydrogen partial pressure is determined by simulation. In these embodiments, the process includes analyzing the middle distillate sample to determine a sample sulfur concentration.

In some embodiments, the process also includes providing a computer comprising a processor coupled to a non-volatile memory, wherein the non-volatile memory stores calculation modules and data. Data including the sample cetane number and optionally the sample sulfur concentration is entered into the computer.

In certain embodiments, a method for evaluating a middle distillate sample is provided. The method comprises analyzing the middle distillate sample to determine a sample sulfur concentration and a sample cetane number. 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 is provided. The reactor under design can include a defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio. A sulfur conversion to achieve the target sulfur concentration of the target product stream is calculated as a function of the sample sulfur concentration and the target sulfur concentration. This can be done 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. A cetane number improvement to achieve the target cetane number of the target product stream is calculated as a function of the sample cetane number and the target cetane number. This can be done by taking the cetane number of the target product stream and subtracting the cetane number of the middle distillate sample. A sample requisite hydrogen partial pressure in the reactor under design is determined as a function of the sulfur conversion and cetane number improvement, wherein the sample requisite hydrogen partial pressure is determined experimentally or by simulation. A severity index is calculated as a function of the sample requisite hydrogen partial pressure. This can be done 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 and target cetane number with approximately the defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio.

In some embodiments, the sample requisite hydrogen partial pressure is determined by simulation.

In some embodiments, the process also includes providing a computer comprising a processor coupled to a non-volatile memory, wherein the non-volatile memory stores calculation modules and data. Data including the sample cetane number and the sample sulfur concentration is entered into the computer.

In some embodiments the hydrotreating process is hydrogenation, hydrocracking, or both.

In some embodiments, the process also includes calculating a plurality of severity indices corresponding to a plurality of middle distillate samples to produce a database of severity indices. In these embodiments, 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. This can be done 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, hydrotreatment or both hydrodesulfurization and hydrotreatment of a feedstock consisting of a reference middle distillate to achieve approximately the target sulfur concentration, target cetane number or both the target sulfur concentration and cetane number with approximately the defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio. In these embodiments, 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, a cetane number improvement or both a sulfur conversion and a cetane number improvement. The sample requisite hydrogen partial pressure can be determined experimentally or by simulation.

In some embodiments, 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.

In some embodiments, a crude oil is fractionated into one or more streams, wherein the middle distillate sample is one of the streams. In some embodiments, the one or more streams further includes one or more of light gases, a light naphtha stream, a heavy naphtha stream, a vacuum gas oil, and a vacuum residue fraction. In some embodiments, the fractionation is by atmospheric distillation, vacuum distillation, or both.

In some embodiments, the plurality of middle distillate samples is obtained from fractionating a plurality of crude oils. In some embodiments, the plurality of crude oils is from one or more sources of crude oil.

In some embodiments, the sulfur concentration of the middle distillate sample is determined by one or more of the following methods: ASTM D7039, ASTM D2622, ASTM D5453, ASTM D4045 and ASTM D4294. In some embodiments, the cetane number of the middle distillate sample is determined by one or more of the following methods: ASTM D613, ASTM D8183 and ASTM D976.

In some embodiments, the middle distillate sample has a sulfur concentration in the range of from 100-50,000, 100-10,000, 100-1,000, 1,000-50,000, 1,000-10,000, or 10,000-50,000 ppmw sulfur. In some embodiments, the target sulfur concentration of the target product stream is in the range of about 10-1000, 10-500, 10-100, 100-1000, 100-500, or 500-1000 ppmw sulfur.

In some embodiments, the middle distillate sample has a cetane number in the range of about 20-50, 20-45, 20-40, 20-35, 20-30, 20-25, 25-50, 25-45, 25-40, 25-35, 25-30, 30-50, 30-45, 30-40, 30-35, 35-50, 35-45, 35-40, 40-50, or 40-45. In some embodiments, the target cetane number of the target product stream is at least 40, at least 45, at least 48, or at least 52. In some embodiments, the target cetane number of the target product stream is in the range of about 40-55, 40-52, 40-50, 40-48, 40-45, 45-55, 45-52, 45-50, 45-48, 48-55, 48-52, 48-50 or 50-52. In some embodiments, the cetane number improvement is in the range of from 1-25, 5-25, 10-25, 15-25, 20-25, 1-20, 5-20, 10-20, 15-20, 1-15, 5-15, 10-15, 1-10, 5-10, or 1-5. For example, in some embodiments, when the middle distillate is straight run gas oil, the cetane improvement can be about 2. In other embodiments, for example, when the middle distillate is aromatic gas oil, the cetane number improvement can be about 20.

In some embodiments, the hydrogen partial pressure that is required for the hydrodesulfurization and/or hydrotreating reaction of the middle distillate is determined by bench scale experiments at a defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio. In some embodiments, the hydrogen partial pressure that is required for the hydrodesulfurization and/or hydrotreating reaction of the middle distillate is determined by simulation at a defined temperature, liquid hourly space velocity, catalyst age and hydrogen to oil ratio. In some embodiments, the sulfur concentration and/or the cetane number is entered into the commercially available software program. In some embodiments, one or more other variables including carbon number, catalyst activity, catalyst selectivity, hydrogen-to-oil ratio are also entered into the commercially available software program.

In one or more embodiments, the middle distillate feedstock boils in the range of 150-400, 150-370, 180-400, or 180-370° C.

FIG. 2 illustrates a schematic block diagram of modules in accordance with an embodiment of the present invention, system 200a. In this embodiment, a reactor under design is a reactor for hydrodesulfurization. Sulfur concentration receiving module 205 receives the sulfur concentration of the middle distillate sample. Optional cetane number receiving module 210 optionally receives the cetane number of the middle distillate sample. A target sulfur concentration of a target product stream from the reactor under design for hydrodesulfurization is received in module 220. Sulfur conversion calculation module 230 calculates the required sulfur conversion as a function of the sample sulfur concentration and the target sulfur concentration. Hydrodesulfurization hydrogen partial pressure (HPP) requirement receiving module 240 receives 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. Reference feed hydrodesulfurization hydrogen partial pressure (HPP) module 250 receives the 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. Hydrodesulfurization severity index calculation module 260 calculates the 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. Relative cost calculation module 270 calculates the cost to process a feedstock containing the middle distillate sample, as a function of the hydrodesulfurization severity index and the cost to process the reference feedstock.

FIG. 3 illustrates a schematic block diagram of modules in accordance with an embodiment of the present invention, system 200b. In this embodiment, the reactor under design is a reactor for hydrotreatment. The hydrotreatment can include hydrogenation, hydrocracking, or a combination thereof. Cetane number receiving module 210 receives the cetane number of a middle distillate sample. Optional sulfur concentration receiving module 205 optionally receives the sulfur concentration of the middle distillate sample. A target cetane number of a target product stream from the reactor under design for hydrotreatment is received in module 225. Cetane number improvement calculation module 235 calculates the required cetane number improvement as a function of the sample cetane number and the target cetane number. Hydrotreating hydrogen partial pressure (HPP) requirement receiving module 245 receives 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. Reference feed hydrotreating hydrogen partial pressure (HPP) module 255 receives the 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. Hydrotreating severity index calculation module 265 calculates the 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. Relative cost calculation module 270 calculates the cost to process a feedstock containing the middle distillate sample, as a function of the hydrotreating severity index and the cost to process the reference feedstock.

FIG. 4 illustrates a schematic block diagram of modules in accordance with an embodiment of the present invention, system 200c. In this embodiment, the reactor under design is a reactor for hydrodesulfurization and hydrotreatment. The hydrotreatment can include hydrogenation, hydrocracking, or a combination thereof. Sulfur concentration receiving module 205 receives the sulfur concentration of the middle distillate sample. Cetane number receiving module 210 receives the cetane number of the middle distillate sample. A target sulfur concentration of a target product stream from the reactor under design for hydrodesulfurization and hydrotreatment is received in module 220. A target cetane number of the target product stream from the reactor under design for hydrodesulfurization and hydrotreatment is received in module 225. Sulfur conversion calculation module 230 calculated the required sulfur conversion as a function of the sample sulfur concentration and the target sulfur concentration. Cetane number improvement calculation module 235 calculates the required cetane number improvement as a function of the sample cetane number and the target cetane number. Hydrodesulfurization hydrogen partial pressure (HPP) requirement receiving module 240 receives 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. Hydrotreating hydrogen partial pressure (HPP) requirement receiving module 245 receives 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. Reference feed hydrodesulfurization hydrogen partial pressure (HPP) module 250 receives the 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. Reference feed hydrotreating hydrogen partial pressure (HPP) module 255 receives the required hydrogen partial pressure for hydrotreatment of the 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. Hydrodesulfurization severity index calculation module 260 calculates the 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. In some embodiments, the requisite hydrogen partial pressure used for determining the severity index in severity index calculation module 260 is the required hydrogen partial pressure for hydrodesulfurization received in hydrodesulfurization hydrogen partial pressure (HPP) module 250 or the required hydrogen partial pressure for hydrotreatment received in hydrotreating hydrogen partial pressure (HPP) module 255. In some embodiments, the requisite hydrogen partial pressure used for determining the severity index in severity index calculation module 260 is the larger of the two of the required hydrogen partial pressure for hydrodesulfurization received in hydrodesulfurization hydrogen partial pressure (HPP) module 250 or the required hydrogen partial pressure for hydrotreatment received in hydrotreating hydrogen partial pressure (HPP) module 255.

Hydrotreating severity index calculation module 265 calculates the 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. In some embodiments, the requisite hydrogen partial pressure used for determining the severity index in severity index calculation module 265 is the required hydrogen partial pressure for hydrodesulfurization received in hydrodesulfurization hydrogen partial pressure (HPP) module 250 or the required hydrogen partial pressure for hydrotreatment received in hydrotreating hydrogen partial pressure (HPP) module 255. In some embodiments, the requisite hydrogen partial pressure used for determining the severity index in severity index calculation module 265 is the larger of the two of the required hydrogen partial pressure for hydrodesulfurization received in hydrodesulfurization hydrogen partial pressure (HPP) module 250 or the required hydrogen partial pressure for hydrotreatment received in hydrotreating hydrogen partial pressure (HPP) module 255.

Relative cost calculation module 270 calculates the cost to process a feedstock containing the middle distillate sample, as a function of the hydrotreating severity index and the cost to process the reference feedstock.

In some embodiments, the reactor under design is constructed with an increased wall thickness to accommodate an increased required partial pressure to treat a sample when compared to a reference sample.

In certain embodiments, the reactor under design can contain one or more fixed-bed reactors, and operating conditions generally include: a reactor temperature (° C.) in the range of from about 270-430, 300-430, 320-430, 340-430, 270-420, 300-420, 320-420, 340-420, 270-400, 300-400, 320-400, 340-400, 270-380, 300-380, 320-380, 340-360, 270-360, 300-360, 320-360 or 340-360; a hydrogen partial pressure (bar) in the range of from about 30-60, 35-60 or 40-60; a hydrogen gas feed rate (SLt/Lt) of up to about 500, in certain embodiments from about 200-500, 250-500 or 300-500; and a liquid hourly space velocity (h⁻¹), on a fresh feed basis relative to the catalysts, in the range of from about 0.1-10.0, 0.1-6.0, 0.1-5.0, 0.1-4.0, 0.1-2.0, 0.5-10.0, 0.5-5.0, 0.5-2.0, 0.8-10.0, 0.8-6.0, 0.8-5.0, 0.8-4.0, 0.8-2.0, 1.0-10.0, 1.0-6.0, 1.0-5.0, 1.0-4.0 or 1.0-2.0.

An effective quantity of hydrotreating catalyst is provided in the reactor under design, including those possessing hydrotreating functionality, including hydrodesulfurization and/or hydrodenitrification, to remove sulfur, nitrogen and other contaminants. Suitable hydrotreating catalysts (sometimes referred to in the industry as “pretreat catalyst”) contain one or more active metal component(s) of metals or metal compounds (oxides or sulfides) selected from the Periodic Table of the Elements IUPAC Groups 6, 7, 8, 9 and 10. One or more active metal component(s) are typically deposited or otherwise incorporated on a non-acidic support, or a support with relatively low acidity compared with a zeolite, which can include alumina, silica alumina, silica, titania, titania-silica, titania-silicates or combinations including at least one of the foregoing support materials. In certain embodiments, the active metal or metal compound is one or more of Co, Ni and Mo, including combinations such as one or more active metals or metal compounds selected from Co/Mo, Ni/Mo, and Co/Ni/Mo. Combinations of one or more of Co/Mo, Ni/Mo, and Co/Ni/Mo can also be used, for instance, in plural beds or separate reactors in series. The combinations can be composed of different particles containing a single active metal species, or particles containing multiple active species. In certain embodiments, the catalyst particles have a pore volume in the range of about (cc/g) 0.15-1.70, 0.15-1.50, 0.30-1.50 or 0.30-1.70; a specific surface area in the range of about (m²/g) 100-400, 100-350, 100-300, 150-400, 150-350, 150-300, 200-400, 200-350 or 200-300; and an average pore diameter of at least about 10, 50, 100, 200, 500 or 1000 angstrom units. The active metal(s) or metal compound(s) are incorporated in an effective concentration, for instance, in the range of (wt % based on the mass of the oxides, sulfides or metals relative to the total mass of the catalysts) 1-40, 1-30, 1-10, 1-5, 2-40, 2-30, 2-10, 3-40, 3-30 or 3-10.

FIG. 5 shows an exemplary block diagram of a computer system 300 by which the herein calculation modules can be implemented is shown in FIG. 3. Computer system 300 includes a processor 320, such as a central processing unit, an input/output interface 330 and support circuitry 340. In certain embodiments, where the computer system 300 requires a direct human interface, a display 310 and an input device 350 such as a keyboard, mouse or pointer are also provided. The display 310, input device 350, processor 320, and support circuitry 340 are shown connected to a bus 390 which also connects to a memory 360. Memory 360 includes program storage memory 370 and data storage memory 380. Note that while computer system 300 is depicted with direct human interface components display 310 and input device 350, programming of modules and exportation of data can alternatively be accomplished over the input/output interface 330, for instance, where the computer system 300 is connected to a network and the programming and display operations occur on another associated computer, or via a detachable input device as is known with respect to interfacing programmable logic controllers.

Program storage memory 370 and data storage memory 380 can each comprise volatile (RAM) and non-volatile (ROM) memory units and can also comprise hard disk and backup storage capacity, and both program storage memory 370 and data storage memory 380 can be embodied in a single memory device or separated in plural memory devices. Program storage memory 370 stores software program modules and associated data, and in particular stores a sulfur concentration receiving module 205, cetane number receiving module 210, target sulfur concentration of a product stream module 220, target cetane number of a product stream module 225, sulfur conversion calculation module 230, cetane number improvement calculation module 235, hydrodesulfurization hydrogen partial pressure requirement receiving module 240, hydrotreating hydrogen partial pressure requirement receiving module 245, reference feed hydrodesulfurization hydrogen partial pressure (HPP) receiving module 250, reference feed hydrotreating hydrogen partial pressure (HPP) receiving module 255, hydrodesulfurization severity index calculation module 260, hydrotreating severity index calculation module 265, and relative cost calculation module 270. Data storage memory 380 stores data used and/or generated by the one or more modules of the present invention.

The calculated and assigned results in accordance with the systems and methods herein are displayed, audibly outputted, printed, and/or stored to memory for use as described herein.

It is to be appreciated that the computer system 300 can be any general or special purpose computer such as a personal computer, minicomputer, workstation, mainframe, a dedicated controller such as a programmable logic controller, or a combination thereof. While the computer system 300 is shown, for illustration purposes, as a single computer unit, the system can comprise a group/farm of computers which can be scaled depending on the processing load and database size, e.g., the total number of samples that are processed and results maintained on the system. The computer system 300 can serve as a common multi-tasking computer.

Computer system 300 preferably supports an operating system, for example stored in program storage memory 370 and executed by the processor 320 from volatile memory. According to the present system and method, the operating system contains instructions for interfacing the device 300 to the calculation module(s). According to an embodiment of the invention, the operating system contains instructions for interfacing computer system 300 to the Internet and/or to private networks.

In some embodiments, a plurality of middle distillate samples are analyzed to determine a plurality of severity indices. In these embodiments, a database of severity indices is produced. In some embodiments, 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.

In one or more embodiments, the method and system disclosed valorizes middle distillate streams boiling in the range 150-400, 150-370, 180-400, or 180-370° C. derived from various crude oil sources. The middle distillate streams are valorized based on their hydrogen partial pressure requirements for a particular reaction such as hydrodesulfurization, hydrogenation, or hydrocracking. In some embodiments, the operating severity for a particular reaction determines the processability of a feedstock, which in turn determine the value of the stream.

In one or more embodiments, a system and method are provided for evaluating a middle distillate sample and determining a hydrogen partial pressure requirement for the middle distillate if it were to be subjected to hydrodesulfurization and/or hydrotreatment, without first performing the hydrodesulfurization and/or hydrotreatment.

The system and method provide information about middle distillate without performing a hydrodesulfurization and/or hydrotreatment reaction and will help producers, refiners, and marketers to benchmark the oil quality and, as a result, valuate the oils without performing the customary extensive and time-consuming oil assays. The currently used oil assay methods are costly in terms of money and time.

EXAMPLES

The below examples and data are exemplary. The examples were developed using a database generated from extensive pilot plant testing.

A reference middle distillate boiling in the range of 180-370° C. obtained from Arab light crude oil feedstock was analyzed and its density was determined to be 0.8222 g/cm³. Its sulfur concentration was determined to be 1.17 wt % and its cetane number was determined to be 52.8. This reference middle distillate was hydrodesulfurized and hydrotreated to obtain a diesel product that had a sulfur concentration of 58 ppmw. This means that the sulfur conversion was 99.5 wt %. The hydrodesulfurization reactor/hydrotreating reactor was operated at 20 bars of hydrogen partial pressure, a temperature of 355° C., a LHSV of 1.5 h⁻¹ and at 300 StLt of hydrogen per Liter of oil. The cetane number of the product stream was determined to be 54. This means that the cetane number improvement was 1.2.

A middle distillate sample boiling in the range of 180-370° C. obtained from a different source than the source in the reference middle distillate was analyzed and its density was determined to be 0.8445 g/cm³. Its sulfur concentration was determined to be 0.68 wt % of sulfur and its cetane number was determined to be 49.3. This feedstock was hydrodesulfurized and hydrotreated to obtain a diesel product that had a sulfur concentration of 60 ppmw of sulfur. This means that the sulfur conversion was 99.1 wt %. The hydrodesulfurization reactor/hydrotreating reactor was operated at 30 bars of hydrogen partial pressure, a temperature of 355° C., a LHSV of 1.5 h⁻¹ and at 300 StLt of hydrogen per Liter of oil.

The severity index for this comparative example was to be 1.5 calculated by dividing the hydrogen partial pressure requirement of the comparative middle distillate by the hydrogen partial pressure requirement of the reference middle distillate to obtain a product that had a sulfur content of about 60 ppmw.

The capital cost of a unit required to process the comparative feedstock was calculated by multiplying the cost of operating the unit to process the reference feedstock by the severity index, using 0.7 as the value for n.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “including,” “comprising,” or “having,” “containing,” “involving,” and variations thereof herein, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Notably, the figures and examples above are not meant to limit the scope of the present disclosure to a single implementation, as other implementations are possible by way of interchange of some or all the described or illustrated elements. Moreover, where certain elements of the present disclosure can be partially or fully implemented using known components, only those portions of such known components that are necessary for an understanding of the present disclosure are described, and detailed descriptions of other portions of such known components are omitted so as not to obscure the disclosure. In the present specification, an implementation showing a singular component should not necessarily be limited to other implementations including a plurality of the same component, and vice-versa, unless explicitly stated otherwise herein. Moreover, applicants do not intend for any term in the specification or claims to be ascribed an uncommon or special meaning unless explicitly set forth as such. Further, the present disclosure encompasses present and future known equivalents to the known components referred to herein by way of illustration.

The foregoing description of the specific implementations will so fully reveal the general nature of the disclosure that others can, by applying knowledge within the skill of the relevant art(s), readily modify and/or adapt for various applications such specific implementations, without undue experimentation, without departing from the general concept of the present disclosure. Such adaptations and modifications are therefore intended to be within the meaning and range of equivalents of the disclosed implementations, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance presented herein, in combination with the knowledge of one skilled in the relevant art(s). It is to be understood that dimensions discussed or shown are drawings accordingly to one example and other dimensions can be used without departing from the disclosure.

The subject matter described above is provided by way of illustration only and should not be construed as limiting. Various modifications and changes can be made to the subject matter described herein without following the example embodiments and applications illustrated and described, and without departing from the true spirit and scope of the invention encompassed by the present disclosure, which is defined by the set of recitations in the following claims and by structures and functions or steps which are equivalent to these recitations.

In a first implementation of a first embodiment, a method for evaluating a middle distillate sample comprises 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.

In a second implementation of the first embodiment, the sample requisite hydrogen partial pressure of the method of the first implementation of the first embodiment is determined by simulation and wherein the process comprises analyzing the middle distillate sample to determine a sample cetane number.

In a third implementation of the first embodiment, the method of the first or second implementation of the first embodiment further comprises 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.

In a fourth implementation of the first embodiment, the method of any of the first through third implementations of the first embodiment further comprises calculating a relative cost to process the feedstock consisting of the middle distillate sample by the following equation: C2=C1*SIⁿ, 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.

In a fifth implementation of the first embodiment, the method of any of the first through fourth implementations of the first embodiment further comprises 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.

In a sixth implementation of the first embodiment, 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 of the fifth implementation of the first embodiment.

In a seventh implementation of the first embodiment, the sulfur conversion of any of the first through sixth implementations of the first embodiment is calculated by the following equation (as a fraction conversion, where a weight percent conversion is calculated by multiplying the below quotient by 100):

Conversion Sulfur = Sulfur sample - Sulfur target Sulfur sample .

In an eighth implementation of the first embodiment, the severity index of the middle distillate sample of any of the first through seventh implementations of the first embodiment is calculated with the following equation:

SI = hydrogen ⁢ partial ⁢ pressure sample hydrogen ⁢ partial ⁢ pressure reference .

In a first implementation of a second embodiment, a method for evaluating a middle distillate sample comprises 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.

In a second implementation of the second embodiment, the sample requisite hydrogen partial pressure of the first implementation of the second embodiment, is determined by simulation and wherein the process comprises analyzing the middle distillate sample to determine a sample sulfur concentration.

In a third implementation of the second embodiment, the method of the first or second implementations of the second embodiment, further comprises 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.

In a fourth implementation of the second embodiment, the method of any of the first through third implementations of the second embodiment further comprises calculating a relative cost to process the feedstock consisting of the middle distillate sample by the following equation: C2=C1*SIⁿ, 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.

In a fifth implementation of the second embodiment, the method of any of the first through fourth implementations of the second embodiment further comprises 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.

In a sixth implementation of the second embodiment, 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 of the fifth implementation of the second embodiment.

In a seventh implementation of the second embodiment, the cetane number improvement (point value improvement) of any of the first through sixth implementations of the second embodiment is calculated by the following equation:

Cetane ⁢ number ⁢ improvement = Cetane ⁢ number product - Cetane ⁢ number sample

In an eighth implementation of the second embodiment, the severity index of the middle distillate sample of any of the first through seventh implementations of the second embodiment is calculated with the following equation:

SI = hydrogen ⁢ partial ⁢ pressure sample hydrogen ⁢ partial ⁢ pressure reference .

In a ninth implementation of the second embodiment, the hydrotreating process of any of the first through eighth implementations of the second embodiment is hydrogenation, hydrocracking, or both.

In a first implementation of a third embodiment, a method for evaluating a middle distillate sample comprises 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.

In a second implementation of the third embodiment, the sample requisite hydrogen partial pressure of the first implementation of the third embodiment is determined by simulation.

In a third implementation of the third embodiment, the method of the first or second implementations of the third embodiment further comprises 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.

In a fourth implementation of the third embodiment, the method of any of the first through third implementations of the third embodiment further comprises calculating a relative cost to process the feedstock consisting of the middle distillate sample by the following equation: C2=C1*SIⁿ, 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.

In a fifth implementation of the third embodiment, the method of any of the first through fourth implementations of the third embodiment further comprises 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.

In a sixth implementation of the third embodiment, 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 of the fifth implementation of the third embodiment.

In a seventh implementation of the third embodiment, the sulfur conversion of any of the first through sixth implementations of the third embodiment is calculated by the following equation (as a fraction conversion, where a weight percent conversion is calculated by multiplying the below quotient by 100):

Conversion Sulfur = Sulfur sample - Sulfur target Sulfur sample .

In an eighth implementation of the third embodiment, the cetane number improvement (point value improvement) of any of the first through seventh implementations of the third embodiment is calculated by the following equation:

Cetane ⁢ number ⁢ improvement = Cetane ⁢ number product - Cetane ⁢ number sample

In a ninth implementation of the third embodiment, the severity index of the middle distillate sample of any of the first through eighth implementations of the third embodiment is calculated with the following equation:

SI = hydrogen ⁢ partial ⁢ pressure sample hydrogen ⁢ partial ⁢ pressure reference .

In a tenth implementation of the third embodiment, the hydrotreating process of any of the first through ninth implementations of the third embodiment is hydrogenation, hydrocracking, or both.

In a first implementation of a fourth embodiment, a crude oil is fractionated into one or more streams, wherein the middle distillate sample of any of the first implementation of the first embodiment, the first implementation of the second embodiment, or the first implementation of the third embodiment is one of the streams.

In a second implementation of a fourth embodiment, the one or more streams of the first implementation of the fourth embodiment further includes one or more of light gases, a light naphtha stream, a heavy naphtha stream, a vacuum gas oil, and a vacuum residue fraction.

In a third implementation of a fourth embodiment, the fractionation of the first or second implementations of the fourth embodiment is by atmospheric distillation, vacuum distillation, or both.

In a first implementation of a fifth embodiment, the plurality of middle distillate samples of any of the fifth implementation of the first embodiment, the fifth implementation of the second embodiment, or the fifth implementation of the third embodiment is obtained from fractionating a plurality of crude oils.

In a first implementation of a fifth embodiment, the plurality of crude oils of the first implementation of the fifth embodiment is from one or more sources of crude oil.

In a sixth embodiment, the middle distillate sample of any of the above implementations has a sulfur content in the range of about 100-50,000 ppmw sulfur.

In a seventh embodiment, the target sulfur content of the target product stream of any of the above implementations is in the range of about 10-1,000 ppmw.

In an eighth embodiment, the middle distillate feedstock of any of the above implementations has a boiling range in the range of about 150° C. to 400° C.