KR20130124545A - Process and apparatus for hydroprocessing two streams - Google Patents

Abstract

Methods and apparatus are disclosed for hydrotreating two hydrocarbon streams at two different pressures. The hydrogen stream is compressed and separated. The first split compressed stream is further compressed to feed a first hydroprocessing unit that requires a higher pressure for operation. The second split compressed stream is fed to a second hydroprocessing unit which requires a lower pressure. Recycle hydrogen from the second hydrotreatment unit is recycled back to the compression section.

Description

Method and apparatus for hydrotreating two streams {PROCESS AND APPARATUS FOR HYDROPROCESSING TWO STREAMS}

Claiming Priority in US First Applications

This application claims the priority of US Application Nos. 13 / 076,647, 13 / 076,658, 13 / 076,670 and 13 / 076,680, all of which are filed March 31, 2011.

Technical field

The technical field of the present invention is the hydroprocessing of two hydrocarbon streams at different pressures.

Hydrocracking refers to the process by which hydrocarbons are broken down into hydrocarbons of lower molecular weight in the presence of hydrogen and a catalyst. Depending on the desired result, the hydrocracking zone may comprise one or more beds of the same or different catalysts. Hydrocracking is a process used to crack hydrocarbon feeds such as vacuum gas oil (VGO) into diesel, including kerosene and gasoline automotive fuels.

Mild hydrocracking converts a portion of the feed into a lighter product, such as diesel, while improving the quality of unconverted oil that can be supplied to downstream units. Catalytic Cracking Units or other process units are commonly used upstream. As the global demand for diesel vehicle fuels increases relative to gasoline vehicle fuels, mild hydrocracking is considered to bias the product slate to benefit diesel at the expense of gasoline. Mild hydrocracking can be made less stringent than partial conversion hydrocracking or full conversion hydrocracking to balance the production of diesel using FCC units, which are mainly used to produce naphtha. Partial conversion hydrocracking or fully conversion hydrocracking is used to produce diesel with less yield of unconverted oil that can be supplied to downstream units.

Due to environmental concerns and new regulations and legislation, commercial diesels must meet lower and lower limits for contaminants such as sulfur and nitrogen. The new legislation requires substantially complete removal of sulfur from diesel. For example, the Ultra Low Sulfur Diesel (ULSD) requirement for sulfur is usually less than 10 wppm.

Integration of hydrotreating units may involve the situation where one unit is operated at a higher pressure than another unit. For example, hydrocracking units are usually operated at higher pressures than hydrotreating units. Hydrogen must be supplied at different pressures. Excess hydrogen is recycled through a recycle gas compressor dedicated to each hydrotreatment unit.

Thus, there is a continuing need for improved methods of producing more diesel than gasoline from hydrocarbon feedstocks. This method must ensure that diesel meets increasingly stringent product requirements. There is also a need for an improved method of supplying hydrogen to separate process units at different pressures.

It is an object of the present invention to provide a method and apparatus for hydrotreating two streams.

In a method embodiment, the present invention is a method of producing diesel from a hydrocarbon stream, comprising a method comprising compressing a make hydrogen stream in a first compressor to provide a first compressed make-up hydrogen stream. . The first portion of the first compressed makeup hydrogen stream is compressed in a second compressor to provide a second compressed makeup hydrogen stream. The second portion of the first compressed makeup hydrogen stream is taken as a second hydrotreated hydrogen stream. The hydrocarbon stream is hydrocracked in the presence of a second compressed makeup hydrogen stream and a hydrocracking catalyst to provide a hydrocracking effluent stream. The diesel stream is hydrotreated in the presence of a second hydrotreated hydrogen stream and a hydrotreated catalyst to provide a second hydrotreated effluent stream. Finally, at least a portion of the first hydrotreatment effluent stream is fractionated to provide a diesel stream.

In a further method embodiment, the present invention is a method of producing diesel from a hydrocarbon stream comprising a method of compressing a makeup hydrogen stream in a first compressor to provide a first compressed makeup hydrogen stream. The first portion of the first compressed makeup hydrogen stream is compressed in a second compressor to provide a second compressed makeup hydrogen stream. The second portion of the first compressed makeup hydrogen stream is taken as a second hydrotreated hydrogen stream. The diesel stream is hydrotreated in the presence of a second hydrotreated hydrogen stream and a hydrotreated catalyst to provide a second hydrotreated effluent stream. The hydrocarbon stream is hydrocracked in the presence of a first hydroprocessed hydrogen stream comprising a hydrocracking catalyst and a second compressed makeup hydrogen stream to provide an effluent stream. At least a portion of the first hydrotreatment effluent stream is fractionated to provide a diesel stream. The first hydrotreatment effluent stream is separated into a vaporous outgoing first hydrotreatment stream comprising hydrogen. The vaporous first hydrotreatment effluent stream is compressed to provide a recycle hydrogen stream. Finally, a recycle hydrogen stream is added to the first hydrotreated hydrogen stream.

In a further method embodiment, the present invention is a method of producing diesel from a hydrocarbon stream comprising a method of compressing a makeup hydrogen stream in a first compressor to provide a first compressed makeup hydrogen stream. The first portion of the first compressed makeup hydrogen stream is compressed in a second compressor to provide a second compressed makeup hydrogen stream. The hydrocarbon stream is hydrocracked in the presence of a first hydroprocessing hydrogen stream comprising a hydrocracking catalyst and a second compressed makeup hydrogen stream to provide a first hydrotreatment effluent stream. The second portion of the first compressed makeup hydrogen stream is taken as a second hydrotreated hydrogen stream. The diesel stream is hydrotreated in the presence of a second hydrotreated hydrogen stream and a hydrotreated catalyst to provide a second hydrotreated effluent stream. At least a portion of the first hydrotreatment effluent stream is fractionated to provide a diesel stream. Finally, at least a portion of the second hydrotreatment effluent stream is fractionated to provide low sulfur diesel.

In an apparatus embodiment, the present invention includes a diesel production apparatus comprising a makeup hydrogen line for carrying a makeup hydrogen stream. The first compressor in communication with the makeup hydrogen line is for compressing the makeup hydrogen stream to provide a first compressed makeup hydrogen stream. A split in communication with the first compressor is to separate the first compressed makeup hydrogen stream into a second portion comprising a first portion in the first split line and a second hydrotreated hydrogen stream in the second split line. It is for. The second compressor is in communication with the first split line to compress the first portion of the first compressed makeup hydrogen stream to provide a second compressed makeup hydrogen stream in the second compressed makeup hydrogen line. The hydrocracking reactor is in communication with the first split line for hydrocracking the hydrocarbon stream to provide a diesel stream. Finally, the hydrotreating reactor is in communication with the hydrocracking reactor and the second split line for hydrotreating the diesel stream.

In a further device embodiment, the present invention includes a diesel production device comprising a make-up hydrogen line for carrying a make-up hydrogen stream. The first compressor is in communication with the makeup hydrogen line to compress the makeup hydrogen stream to provide a first compressed makeup hydrogen stream. The second compressor is in communication with the first compressor for compressing a portion of the first compressed makeup hydrogen stream to provide a second compressed makeup hydrogen stream. The hydrocracking reactor is in communication with a second compressor for hydrocracking the hydrocarbon stream to provide a diesel stream. Finally, the hydrotreating reactor is in communication with the hydrocracking reactor and the first compressor for hydrotreating the diesel stream.

In a further device embodiment, the present invention includes a diesel production device comprising a make-up hydrogen line for carrying a make-up hydrogen stream. The first compressor is in communication with the makeup hydrogen line to compress the makeup hydrogen stream to provide a first compressed makeup hydrogen stream. The hydrotreating reactor is in communication with the first compressor for hydrotreating the diesel stream. The second compressor is in communication with the first compressor to compress a portion of the first compressed makeup hydrogen stream to provide a second compressed makeup hydrogen stream. The hydrocracking reactor is in communication with a second compressor for hydrocracking the hydrocarbon stream into hydrocarbons having a lower boiling point. A cold separator separates the second hydroprocessing effluent stream into a vaporous second hydroprocessing effluent stream comprising hydrogen in the overhead line and a liquid second hydroprocessing effluent stream in the bottom line. In communication with the hydrotreating reactor, wherein the second compressor is in communication with the overhead line.

In another method embodiment, the invention is a method of hydrotreating two hydrocarbon streams, comprising a method comprising compressing a makeup hydrogen stream in a first compressor to provide a first compressed makeup hydrogen stream. The first portion of the first compressed makeup hydrogen stream is compressed in a second compressor to provide a second compressed makeup hydrogen stream. The second portion of the first compressed makeup hydrogen stream is taken as a second hydrotreated hydrogen stream. The first hydrocarbon stream is hydrotreated in the presence of a first hydroprocessing hydrogen stream comprising a first hydrotreatment catalyst and a second compressed makeup hydrogen stream to provide a first hydrotreatment effluent stream. The second hydrocarbon stream is hydrotreated in the presence of a second hydrotreated hydrogen stream comprising a second hydrotreated catalyst and a first compressed makeup hydrogen stream to provide a second hydrotreated effluent stream. The second hydrotreatment effluent stream is separated to provide a vaporized second hydrotreatment effluent stream. Finally, a second hydroprocessing effluent stream in the vapor phase is added to the makeup hydrogen stream upstream of the second compressor.

In a further method embodiment, the invention is a method of hydrotreating two hydrocarbon streams, comprising a method comprising compressing a makeup hydrogen stream in a first compressor to provide a first compressed makeup hydrogen stream. The first portion of the first compressed makeup hydrogen stream is compressed in a second compressor to provide a second compressed makeup hydrogen stream. The second portion of the first compressed makeup hydrogen stream is taken as a second hydrotreated hydrogen stream. The first hydrocarbon stream is hydrotreated in the presence of a first hydrotreated hydrogen stream comprising a hydrocracking catalyst and a second compressed makeup hydrogen stream to provide a first hydrotreatment effluent stream. The second hydrocarbon stream is hydrotreated in the presence of a second hydroprocessed hydrogen stream and a hydrotreating catalyst to provide a second hydrotreatment effluent stream. The second hydrotreatment effluent stream is separated to provide a vaporized second hydrotreatment effluent stream. Finally, a second hydroprocessing effluent stream in the vapor phase is added to the first portion of the first compressed makeup hydrogen stream.

In a further method embodiment, the invention is a method of hydrotreating two hydrocarbon streams, comprising a method comprising compressing a makeup hydrogen stream in a first compressor to provide a first compressed makeup hydrogen stream. The first portion of the first compressed makeup hydrogen stream is compressed in a second compressor to provide a second compressed makeup hydrogen stream. The second portion of the first compressed makeup hydrogen stream is compressed as a second hydrotreated hydrogen stream. The first hydrocarbon stream is hydrocracked in the presence of a first hydrotreatment hydrogen stream comprising a hydrocracking catalyst and a second compressed makeup hydrogen stream to provide a first hydrotreatment effluent stream. The second hydrocarbon stream is hydrotreated in the presence of a second hydroprocessed hydrogen stream and a hydrotreating catalyst to provide a second hydrotreatment effluent stream. The second hydrotreatment effluent stream is separated to provide a vaporized second hydrotreatment effluent stream. A second hydrotreatment effluent stream in the vapor phase is added to the makeup hydrogen stream upstream of the first compressor.

In another device embodiment, the present invention includes a device for hydrotreating two hydrocarbon streams comprising a device hydrogen line for carrying a makeup hydrogen stream. The first compressor is in communication with the makeup hydrogen line to compress the makeup hydrogen stream to provide a first compressed makeup hydrogen stream. The split is in communication with the first compressor to separate the first compressed makeup hydrogen stream into a first portion in the first split line and a second portion in the second split line. The second compressor is in communication with the first split line to compress the first portion of the first compressed makeup hydrogen stream to provide a second compressed makeup hydrogen stream in the second compressed makeup hydrogen line. The first hydrotreating reactor is in communication with the first split line for hydrotreating the first hydrocarbon stream. The second hydrotreating reactor is in communication with the second split line for hydrotreating the second hydrocarbon stream. The separator is in communication with a second hydrotreatment reactor to separate the second hydrotreatment effluent stream into a vaporous second hydrotreatment effluent stream containing hydrogen in the overhead line. Finally, the second compressor is in communication with the overhead line.

In a further apparatus embodiment, the present invention further comprises an apparatus for hydrotreating two hydrocarbon streams, comprising a makeup hydrogen line for carrying the makeup hydrogen stream. The first compressor is in communication with the makeup hydrogen line to compress the makeup hydrogen stream to provide a first compressed makeup hydrogen stream. The split is in communication with the first compressor to separate the first compressed makeup hydrogen stream into a first portion in the first split line and a second portion in a second split line comprising a second hydroprocessed hydrogen stream. The second compressor is in communication with the first split line to compress the first portion of the first compressed makeup hydrogen stream to provide a second compressed makeup hydrogen stream in the second compressed makeup hydrogen line. The hydrocracking reactor is in communication with the first split line for hydrocracking the first hydrocarbon stream to hydrocarbons having a lower boiling point. The hydrotreating reactor is in communication with the second split line for hydrotreating the second hydrocarbon stream. The separator is in communication with the hydrotreatment reactor to separate the second hydrotreatment effluent stream into a vaporous second hydrotreatment effluent stream containing hydrogen in the overhead line. Finally, the second compressor communicates with the overhead line at the intersection on the first split line.

In a further device embodiment, the present invention includes an apparatus for hydrotreating two hydrocarbon streams, including a makeup hydrogen line for carrying makeup hydrogen streams. The first compressor is in communication with the makeup hydrogen line to compress the makeup hydrogen stream to provide a first compressed makeup hydrogen stream. The split is in communication with the first compressor to separate the first compressed makeup hydrogen stream into a first portion in the first split line and a second portion in a second split line comprising a second hydroprocessed hydrogen stream. The second compressor is in communication with the first split line to compress the first portion of the first compressed makeup hydrogen stream to provide a second compressed makeup hydrogen stream in the second compressed makeup hydrogen line. The hydrocracking reactor is in communication with the first split line for hydrocracking the first hydrocarbon stream to hydrocarbons having a lower boiling point. The hydrotreating reactor is in communication with the second split line for hydrotreating the second hydrocarbon stream. The separator is in communication with the hydrotreatment reactor to separate the second hydrotreatment effluent stream into a vaporous second hydrotreatment effluent stream containing hydrogen in the overhead line. The first compressor communicates with the overhead line at the intersection on the makeup hydrogen line.

According to the present invention, a method and apparatus for hydrotreating two streams can be obtained.

1 is a simplified process flow diagram of an embodiment of the present invention.
2 is a simplified process flow diagram of a variant of the invention.

Justice

The term "communication" means that a material flow is operably allowed between the listed components.

The term "downstream communication" means that at least a portion of the material flowing with respect to the subject in downstream communication can be operatively flowable from the object with which the subject is in communication.

The term "upstream communication" means that at least a portion of the material flowing from the subject in upstream communication can operatively flow into the object with which the subject is in communication.

The term "column" means distillation column (s) for separating one or more components having different volatility. Unless otherwise specified, each column includes a condenser on the overhead of the column to condense a portion of the overhead stream and reflux back to the top of the column, and include a reboiler at the bottom of the column to vaporize a portion of the bottom stream. To the bottom of the column. The feed to the column can be preheated. The upper pressure is the pressure of the overhead steam at the steam outlet of the column. The bottom temperature is the liquid bottom outlet temperature. The overhead and bottom lines refer to the net line from the column downstream of the reflux or reboiling to this column.

As used herein, the term "True Boiling Point" refers to ASTM D2892, which corresponds to ASTM D2892 for the production of liquefied gas, distillate fractionation and standardized quality residues from which analytical data can be obtained. Means a test method for determining the boiling point of the mass, and yields the mass for the above-described classification in which a graph of temperature versus distilled mass% produced using 15 theoretical plates in a column with a 5: 1 reflux ratio is determined. And it means to determine by volume.

As used herein, the term "conversion" means that the feed is converted to a material that boils in the diesel boiling range or below the diesel boiling range. Cut points in the diesel boiling range are from 343 ° C. (650 ° F.) to 399 ° C. (750 ° F.) when using true boiling point distillation.

As used herein, the term “diesel boiling range” means hydrocarbon boiling in the range between 132 ° C. (270 ° F.) and 399 ° C. (750 ° F.) when using true boiling point distillation.

details

Two stage hydrotreatment units are often operated at different pressures, and both hydrotreatment units each have their own dedicated recycle gas compressor. When one of the hydrotreating units is a conventional hydrotreating unit, the hydrotreating unit has a recirculating gas compressor, which withdraws the gas from the cold separator downstream of the hydrotreating reactor and hydroprocesses the hydrogen rich gas. Recirculate to the reactor inlet. Makeup gas streams are usually required for two hydrotreatment units.

The recycle gas compressor in one of the hydrotreatment units can be removed by withdrawing the gas from the makeup gas compression system used by the first hydrotreatment unit, which may be a hydrocracking unit. The makeup gas stream can be withdrawn from the discharge of the first compression stage and can be returned upstream or downstream of the first compression stage. The second compression stage downstream of the first compression stage can raise the makeup gas pressure to the higher pressure required by the first hydroprocessing unit. Only some of the makeup hydrogen is directed to a second hydrotreatment unit, which may be a hydrotreating unit.

Mild hydrocracking reactors operate at low sensitivity and therefore have a low degree of conversion. Diesel produced from mild hydrocracking is not of sufficient quality to meet applicable fuel specifications, particularly with regard to sulfur. As a result, the diesel resulting from mild hydrocracking can be treated in a hydrotreating unit to allow mixing into the final diesel. In many cases, it is attractive to integrate mild hydrocracking units and hydrotreating units to lower capital and operating costs.

Returning to FIG. 1, the apparatus 8 and method for generating diesel include a compression section 10, a first hydrotreatment unit 12, a second hydrotreatment unit 14 and a fractionation section 16. do. The first hydrocarbon feed 38 can be supplied to the first hydrotreatment unit 12 and can be converted to a hydrocarbon having a lower boiling point, such as diesel. Effluent from the first hydrotreatment unit 12 may be fractionated in the fractionation section 16, and the fractionated product may proceed to the second hydrotreatment unit 14. The first hydrotreatment unit 12 operates at a higher pressure than the second hydrotreatment unit 14.

The makeup hydrogen stream in makeup hydrogen line 20 is fed to a first compressor 22 to raise the pressure of the makeup hydrogen stream and provide a first compressed makeup hydrogen stream in line 24. The make-up hydrogen stream in line 20 firstly undergoes a second vapor phase in line 98 at first intersection 25 to provide a combined stream at line 26 upstream of the first compressor 22. May be joined by a hydrotreatment effluent stream. The combined stream in line 26 may now be compressed in the first compressor 22 to provide a first compressed makeup hydrogen stream in the compressed makeup hydrogen line 24. The first compressor 22 may correspond to a series of compressors.

The split 27 on the compressed makeup hydrogen line 24 takes the first portion of the compressed makeup hydrogen in the first split line 28, and the second portion of the compressed makeup hydrogen in the second split line 30. Makes it possible to take in. The second portion of the compressed makeup hydrogen in the second split line 30 proceeds to the second hydroprocessing unit 14.

The first portion of compressed makeup hydrogen in the first split line 28 may be further compressed in a second compressor 32, which is a series of lines for providing a second compressed makeup stream in line 34. It may be a compressor of. The second compressed makeup stream in line 34 may be joined by a recycle hydrogen stream in line 56 to provide a first hydroprocessed hydrogen stream in line 36. The first hydrotreatment unit 12 operates at a higher pressure than the second hydrotreatment unit 14.

Taken from the second compressed makeup hydrogen stream, the first hydroprocessed hydrogen stream in line 36 may join the first hydrocarbon feed stream to provide a first hydroprocessed feed stream in line 40.

The hydrocarbon feed stream is introduced in line 38 via a surge tank, as the case may be. In one aspect, the methods and apparatus described herein are particularly useful for hydrotreating hydrocarbon feedstocks. Exemplary hydrocarbon feedstocks include atmospheric gas oil, VGO, deasphalted residue, vacuum residue, and atmospheric residue, coker distillate, straight run distillate, solvent-deasphalted oil. Hydrocarbon streams with component boiling points above 288 ° C. (550 ° F.), such as pyrolysis derived oils, high boiling point synthetic oils, cycle oils, hydrocracked feeds, cat cracker distillates, and the like. These hydrocarbon feedstocks may contain 0.1 to 4 weight percent sulfur.

Suitable hydrocarbon feedstocks are VGO or at least 50% by weight, usually at least 75% by weight, and other hydrocarbon fractions whose components boil at temperatures above 399 ° C (750 ° F). Conventional VGOs usually have a boiling point range between 315 ° C. (600 ° F.) and 565 ° C. (1050 ° F.).

The first hydrotreatment reactor 42 may be in downstream communication with one or more compressors 22 and 32 on the make-up hydrogen line 20, the first hydrocarbon feed line 38, and the first split line 28. The first hydrotreatment feed stream may be heat exchanged with the first hydrotreatment effluent stream in line 44 and prior to entering the first hydrotreatment reactor 42 for hydrotreating the first hydrocarbon stream. It is further heated in an ignited heater. The first hydrotreatment reactor 42 may include various combinations of one or more vessels, multiple catalyst beds in each vessel, hydrotreating catalysts in one or more vessels, and hydrocracking catalysts.

The hydrotreating performed in the first hydrotreating reactor 42 may be hydrocracking. In one aspect, the first hydrotreatment unit may be a hydrocracking unit 12, in which case the first hydrotreatment hydrogen stream is a hydrocracking hydrogen stream in line 36 and the first hydrotreatment reactor 42. Is a hydrocracking reactor in downstream communication with the first split line 28 and the feed stream in line 40 is a hydrocracking feed stream.

Hydrocracking refers to the process by which hydrocarbons are broken down into hydrocarbons of lower molecular weight in the presence of hydrogen. In some embodiments, the hydrocracking reaction allows for total conversion of at least 20 volume percent and volumetric hydrocarbon feed, typically greater than 60 volume percent, to a product boiling below the diesel cut point. The hydrocracking reactor 42 may operate with a partial conversion of more than 50% by volume or a full conversion of at least 90% by volume based on the total conversion. Full conversion is effective to maximize diesel. The first vessel or bed in the hydrocracking reactor 42 may comprise a hydrotreating catalyst for the purpose of demetallization, desulfurization or denitrogenation of the hydrocracking feed.

The hydrocracking reactor 42 may be operated at mild hydrocracking conditions. Under mild hydrocracking conditions, the feed is selectively converted to heavy products such as diesel and kerosene, with less light hydrocarbons such as naphtha and gas being obtained. The pressure is also suitable to limit the hydrogenation of the subproduct to the optimum level for downstream processing. Mild hydrocracking conditions allow 20 to 60 vol%, preferably 20 to 50 vol%, of the hydrocarbon feed to be total converted, or the hydrocarbon feed to be converted to a product boiling below the diesel cut point. In mild hydrocracking operations, hydrotreating catalysts play a greater role than hydrocracking catalysts or more than hydrocracking catalysts in conversion. The conversion across the hydrotreating catalyst can be a significant part of the overall conversion. If the first hydrotreatment reactor 42 is intended for mild hydrocracking, all of the mild hydrocracking reactors 42 are all hydrotreating catalysts, all are hydrocracking catalysts, or some beds are hydrotreating catalysts and some are The bed is expected to be loaded with hydrocracking catalyst. In the last case, the bed of hydrocracking catalyst can usually follow the bed of hydrotreating catalyst. Most typically, three beds of hydrotreating catalyst may be followed by zero, one or two beds of hydrocracking catalyst.

The first hydrotreatment reactor 42 in FIG. 1 has four beds in one reactor vessel. If mild hydrocracking is desired, it can be envisioned that the three first catalyst beds comprise a hydrotreating catalyst and the last catalyst bed contains a hydrocracking catalyst. If partial or complete hydrocracking is desired, an additional bed of hydrocracking catalyst may be used as opposed to mild hydrocracking.

In one aspect, for example, if a balance of intermediate distillate and gasoline in the converted product is desired, mild hydrocracking may be performed in the first hydrotreatment reactor 42, with an amorphous silica-alumina base or low level. Hydrocracking catalysts utilizing zeolite bases are combined with one or more Group VIII or VIB group metal hydrogenation components. In another embodiment, when intermediate distillates are significantly preferred over gasoline production in the converted product, partial or complete hydrocracking may be performed in the first hydrotreatment reactor 42, wherein the catalyst is generally any crystalline. A zeolite decomposition base, on which a group metal hydrogenation component is placed. Additional hydrogenation components may be selected from the VIB group for integration with the zeolite base.

Zeolite decomposition bases are sometimes referred to in the art as molecular sieves and usually consist of silica, alumina and one or more exchangeable cations such as sodium, magnesium, calcium, rare earth metals and the like. These bases are also characterized by relatively uniform diameter crystalline pores of 4 to 14 angstroms (10 ^-10 meters). Preference is given to employing zeolites having a relatively high silica / alumina molar ratio of 3 to 12. Suitable zeolites found in nature include, for example, mordenite, stilbite, hulanite, ferrierite, dachiardite, caberzite, erionite and phosite. Suitable synthetic zeolites include, for example, B crystal type, X crystal type, Y crystal type and L crystal type. Examples include synthetic phossite and mordenite. Preferred zeolites are those having a crystal pore diameter of between 8 and 12 angstroms (10 ^-10 meters), with a silica / alumina mole ratio of 4 to 6. One example of zeolites belonging to the preferred group is synthetic Y molecular sieves.

Naturally occurring zeolites are usually found in sodium form, alkaline earth metal form or mixed form. Synthetic zeolites are almost always prepared in the form of sodium first. In any case, ammonium salt followed by heating to decompose the ammonium ions associated with the zeolite and / or with the majority or all of the original zeolite monovalent metal being ion exchanged with the polyvalent metal for use as a decomposition base. It is preferred to be ion-exchanged, which leaves hydrogen ions and / or exchange sites in place and these hydrogen ions and / or exchange sites are decationic in practice by further removing water. “Decationized” Y zeolites or hydrogens having these properties are described in more detail in US Pat. No. 3,130,006.

Mixed polyvalent metal-hydrogen zeolites may be prepared by first ion exchange with an ammonium salt, subsequent partial back exchange with the polyvalent metal salt, and subsequent calcination. In some cases, as in the case of synthetic mordenite, the hydrogen form can be prepared by direct acid treatment of alkali metal zeolites. In one aspect, the preferred decomposition base is one that lacks at least 10 percent and preferably at least 20 percent metal-cation based on the initial ion exchange capacity. In another embodiment, the preferred and stable class of zeolites is that at least 20 percent of the ion exchange capacity is met by hydrogen ions.

The active metals employed in the preferred hydrocracking catalyst of the present invention as the hydrogen generating component are metals belonging to the Group VIII, that is, iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum. In addition to these metals, other promoters, including metals of the VIB group, such as molybdenum and tungsten, may also be employed with this. The amount of hydrogenation metal in the catalyst can vary over a wide range. Roughly speaking, any amount between 0.05 and 30 weight percent may be used. In the case of noble metals, it is usually preferred to use 0.05 to 2% by weight.

A method for incorporating hydrogen-generating metals is to contact the base material with an aqueous solution of a suitable compound of the desired metal, in which the metal is in cation form. Subsequently adding the selected hydrogenation metal (s), the resulting catalyst powder is subsequently filtered, dried, if desired pelleted with additional lubricants, binders and the like, to activate the catalyst and to decompose the ammonium ions. For example, calcined in air at a temperature of 371 ° C. to 648 ° C. (700 ° F. to 1200 ° F.). Alternatively, the base component may first be pelleted, followed by activation by addition and calcination of the hydrogen evolution component.

The catalysts described above may be employed in undiluted form, or the powdered catalyst may be other relatively less activated catalysts, diluents or aluminas, silica gels, silica-alumina cogels, activated clays in proportions of 5 to 90% by weight. May be mixed and copelted with a binder such as the like. These diluents may be employed as commonly said or may contain small amounts of additional hydrogenated metals such as VIB group and / or Group VIII metals. Additional metal catalyzed hydrocracking catalysts may also be used in the process of the invention, including, for example, aluminum phosphate molecular sieves, crystalline chromosilicates and other crystalline silicates. Crystalline chromosilicates are more fully described in US 4,363,718.

According to one method, hydrocracking conditions may be between 290 ° C. (550 ° F.) and 468 ° C. (875 ° F.), preferably between 343 ° C. (650 ° F.) and 435 ° C. (815 ° F.), and 3.5 MPa (500 psig). Pressures from 3000 to 20.7 MPa (3000 psig), Liquid Hourly Space Velocity (LHSV) from 1.0 to 2.5 hr ⁻¹ and hydrogen ratios from 421 to 2,527 Nm ³ / m ³ oil (2,500 to 15,000 scf / bbl) It may include. If mild hydrocracking is desired, the conditions may range from a temperature of 315 ° C. (600 ° F.) to 441 ° C. (825 ° F.), a pressure of 5.5 MPa to 13.8 MPa (800 to 2000 psig) (gauge pressure) or more preferably of 6.9 to Pressure (gauge pressure) of 11.0 Mpa (1000 to 1600 psig), Liquid Hourly Space Velocity (LHSV) of 0.5 to 2 hr ⁻¹ and 421 to 1,685 Nm ³ / m ³ oil (2,500 to 10,000 scf / bbl) of hydrogen.

The hydrotreating performed in the first hydrotreating reactor 42 may be hydrotreating. Hydrotreating is the process by which hydrogen gas is brought into contact with a hydrocarbon in the presence of a suitable catalyst, the catalyst being primarily active in removing heteroatoms such as sulfur, nitrogen and metals from hydrocarbon feed fuels. It is a catalyst. In hydrotreating, hydrocarbons with double and triple bonds may be saturated. Aromatic compounds may also be saturated. Some hydrotreating methods are specially configured to saturate aromatic compounds.

Suitable hydrotreatment catalysts for use in the present invention are any known conventional hydrotreatment catalysts, which have a large surface area support material, preferably at least one Group VIII metal, preferably iron, cobalt and nickel, more preferably on alumina. Preferably it comprises a catalyst consisting of cobalt and / or nickel and at least one Group VI metal, preferably molybdenum and tungsten. Other suitable hydrotreating catalysts include noble metal catalysts as well as zeolite catalysts, wherein the noble metal is selected from palladium and platinum. In the scope of the present invention, more than one type of hydrotreating catalyst is used in the second vessel in the second hydrotreating reactor 92. Group VIII metals are usually present in amounts ranging from 2 to 20% by weight, preferably from 4 to 12% by weight. Group VI metals are usually present in amounts ranging from 1 to 25% by weight, preferably from 2 to 25% by weight.

Preferred hydrotreating reaction conditions are 290 ° C. (550 ° F.) to 455 ° C. (850 ° F.), suitably 316 ° C. (600 ° F.) to 427 ° C. (800 ° F.), with a hydrotreating catalyst or a combination of hydrotreating catalysts. Preferably a temperature of 343 ° C. (650 ° F.) to 399 ° C. (750 ° F.), 3.4 MPa (500 psig), preferably 4.1 MPa (600 psig) to 6.2 MPa (900 psig), 0.5-4 hr ^{− 1} , preferably from 168 to 1,011 Nm ³ / m ³ oil (1,000-6,000 scf / ^l ) in liquid hourly space velocity (LHSV) and diesel feedstock of fresh hydrocarbon feedstocks, preferably 1.5 to 3.5 hr ^-1 . bbl), preferably from 168 to 674 Nm ³ / m ³ oil (1,000-4,000 scf / bbl).

The hydrotreating performed in the first hydrotreatment reactor 42 may be hydroisomerization. Hydroisomerization may also include catalytic dewaxing. Hydroisomerization is in one embodiment at least 10 percent of the hydrocarbon feedstock, in another embodiment at least 50 percent and in another embodiment 10-90 percent of the n-paraffins converted to effective isoparaffins, up to 0 ° C. (32 ° F.) At least one cloud point value, a pour point value below 0 ° C. (32 ° F.), and / or a Cold Filter Plugging Point (CFPP) below 0 ° C. (32 ° F.). Provide to the effluent. In general, the conditions for such hydroisomerization are temperatures from 260 ° C. (500 ° F.) to 371 ° C. (700 ° F.), pressures from 1.38 MPa (200 psig) to 8.27 MPa (1200 psig), 1.0 hr ⁻¹ to 10 hr. It comprises a ratio of hydrogen -; (liquid hourly space velocity LHSV ) , and 168 to ^{1,011 Nm 3 / m 3 oil (} 6,000 scf / bbl 1,000) -1 liquid hourly space velocity of the fresh hydrocarbon feed. However, other hydroisomerization conditions are also possible, depending on the quality of the feed and other factors.

Suitable hydroisomerization catalysts are any known conventional hydroisomerization catalysts. For example, suitable catalysts may include zeolite components, hydrogen / dehydrogen components, and / or acidic components. In some forms, the catalyst may comprise at least one Group VIII metal, such as a noble metal (ie, platinum or palladium). In another form, the catalyst may also include silico alumino phosphate and / or zeolite aluminosilicate. Examples of suitable catalysts are disclosed in US Pat. No. 5,976,351, US Pat. No. 4,960,504, US Pat. No. 4,788,378, US Pat. No. 4,683,214, US Pat. Can be.

The first hydrotreatment effluent exits the first hydrotreatment reactor 42 in line 44. If the first hydrotreatment reactor 42 is a hydrocracking reactor, the first hydrotreatment effluent in line 44 is a hydrocracking effluent. The first hydrotreatment effluent in line 44 may be heat exchanged with the first hydrotreatment feed in line 40 and, in an embodiment, may be cooled prior to entering first cold separator 46. The first low temperature separator 46 is in downstream communication with the first hydroprocessing reactor 42. The first cold separator is a pressure just below the pressure of the first hydrotreatment reactor 42 and 46 ° C. to 63 ° C. in view of the pressure drop to maintain hydrogen and light gases at overhead and usually liquid hydrocarbons at the bottom. (115 ° F. to 145 ° F.). The first low temperature separator 46 provides a first hydroprocessing effluent stream in vapor phase comprising a liquid first hydroprocessing effluent stream in the bottom line 50 and hydrogen in an overhead line 48. . The first cold separator also has a boot for collecting the aqueous phase in line 52.

The vaporous first hydroprocessing effluent stream, which may be a vaporous hydrocracking effluent stream in line 48, may be compressed in recycle gas compressor 54 to provide a recycle hydrogen stream in line 56. have. The recycle gas compressor 54 may be in downstream communication with the first hydroprocessing reactor 42, which may be a hydrocracking reactor. Recycle gas compressor 54 may compress the vaporous first hydroprocessing effluent stream comprising hydrogen in line 48 to provide a recycle hydrogen stream in recycle hydrogen line 56. The second compressed makeup hydrogen stream in line 34 is a recycle in line 56, which is a vaporized first hydroprocessing effluent stream compressed to provide a first hydroprocessed hydrogen stream in line 36. Join with hydrogen. Hydrocracking reactor 42 is communicated downstream with recycle hydrogen line 56 via lines 36 and 40.

As described above, in an embodiment, the recycle hydrogen stream in line 56 may join the second compressed makeup hydrogen stream in line 34 downstream of recycle gas compressor 54. However, if the pressure of the recycle hydrogen stream in line 56 is too high and thus cannot allow the makeup hydrogen stream without adding more compressor upstream of the second compressed makeup hydrogen line 34, the second compression The make-up hydrogen stream may be added to the vaporous hydrocracking effluent stream in line 48 upstream of the recycle gas compressor 54. However, this increases the duty on the recycle gas compressor 54 due to higher throughput.

At least a portion of the first hydrotreatment effluent stream in line 44 is fractionated in the fractionation section 16 in downstream communication with the first hydrotreatment reactor 42 to provide a second hydrocarbon stream in line 86. Can be. In one aspect, the liquid first hydroprocessing effluent stream, which may include the liquid hydrocracking effluent stream in line 50, may be classified in the fractionation section 16. In a further aspect, the sorting section 16 may comprise a cold flash drum 58. The liquid first hydroprocessing effluent stream in line 50 is derived from the liquid first hydroprocessing effluent stream from the light final stream in overhead line 64 and the light liquid stream in lower line 62. To provide, it can be flashed in a low temperature flash drum 58 which can be operated at the same temperature as the low temperature separator 46 and at a lower pressure that is between 1.4 MPa and 3.1 MPa (200 to 450 psig) (gauge pressure). have. An aqueous stream in line 52 from the boot of the cold separator can also be directed to the cold flash drum 58. The flash aqueous stream is removed from the boot in the cold flash drum 58 in line 66. The light liquid stream in the bottom line 62 may be further fractionated in the fractionation section 16.

The fractionation section 16 may comprise a stripping column 70 and a fractionation column 80. The light liquid stream in the bottom line 62 may be heated and fed to the stripping column 70. The light liquid stream, the liquid first hydrotreatment effluent, may be stripped with steam from line 72 to provide a light final stream of hydrogen, hydrogen sulfide, steam, and other gases at overhead line 74. Part of the light final stream may be condensed and refluxed to the stripping column 70. The stripping column 70 may be operated at a bottom temperature of 232 ° C. to 288 ° C. and an overhead pressure of 690 to 1034 kPa (100 to 150 psig) (gauge pressure). The hydrotreated bottom stream in line 76 may be heated in an ignited heater and fed to the fractionation column 80. Part of the hydrotreated bottom stream may be reboiled and returned to stripping column 70 instead of using steam stripping.

The fractionation column 80 is also overhead naphtha stream in line 84, diesel stream in line 86, and unconverted in line 88, which may be suitable for further processing, such as in an FCC unit. The hydrocracked bottoms can be stripped from the line 82 with steam to provide an oil stream from the side cut. The overhead naphtha stream in line 84 may require additional treatment prior to mixing in the gasoline pool. This will usually require catalytic reforming to improve the octane number. The reforming catalyst will often require that the overhead naphtha be further desulfurized in the naphtha hydrotreater prior to reforming. In one aspect, the hydrocracked naphtha can be desulfurized in an integrated hydrotreating unit. It may also be invented to take additional side cuts to provide a separate light diesel or kerosene stream taken from the heavy diesel stream in line 86. Part of the overhead naphtha stream in line 84 may be condensed and refluxed to fractionation column 80. The fractionation column 80 may be operated at a bottom temperature between 288 ° C. and 385 ° C. (550 ° F. to 725 ° F.), preferably between 315 ° C. and 357 ° C. (600 ° F. to 675 ° F.) and at or near atmospheric. Part of the hydrocracked bottoms stream may be reboiled and returned to fractionation column 80 instead of using steam stripping.

The diesel stream in line 86 may have reduced sulfur content, but may not meet the Low Sulfur Diesel (LSD) specification with sulfur below 50 wppm, the ULSD specification with sulfur below 10 wppm, or other specifications. Thus, it can be further finished in a second hydrotreatment unit 14, which can be a diesel hydrotreatment unit 14. Accordingly, the diesel stream in line 86 may be a second hydrocarbon stream. The second hydrocarbon stream may have a lower average boiling point than the first hydrocarbon stream.

The second hydrocarbon stream in line 86 includes a second portion of the first compressed makeup hydrogen stream from the second split line 30 to provide a second hydroprocessing feed stream 90. May be joined by a hydrotreatment stream. The second hydrocarbon stream in line 86 may also be mixed with a common feed not shown. Second hydrotreatment feed stream 90 may be heat exchanged with a second hydrotreatment effluent stream in line 94, may be further heated in an ignited heater, and second hydrotreatment reactor 92 May be directed to. As a result, the second hydroprocessing reactor is in downstream communication with the fractionation section 16, the splits 27 and the first hydroprocessing reactor 42. In a second hydrotreatment reactor 92, a second hydrocarbon stream, which may be a diesel stream, is present in the presence of a second hydrotreatment catalyst and a second hydrotreatment hydrogen stream to provide a second hydrotreatment effluent stream 94. Hydrotreated.

The second hydrotreatment reactor 92 may include more than one vessel and multiple catalyst beds. The second hydroprocessing reactor 92 in FIG. 1 has two beds in one reactor vessel. The second hydrotreatment reactor 92 may be operated as a hydrocracking reactor, hydrotreating reactor or hydroisomerization reactor loaded with a suitable catalyst as described above for the first hydrotreatment reactor 42. The second hydrotreatment reactor 92 may be communicated downstream with the first hydrotreatment reactor 42 and the second split line 30, which may be a hydrocracking reactor.

The hydrotreating performed in the second hydrotreating reactor 92 may be hydrotreating. In one aspect, the second hydrotreatment unit may be a hydrotreatment unit 14, in which case the second hydrotreatment hydrogen stream is a hydrotreatment hydrogen stream in line 30, and the second hydrotreatment reactor 92 Is a hydrotreating reactor in downstream communication with the second split line 30 and the feed stream in line 90 is a hydrotreatment feed stream.

In the hydrotreating reactor 92, the hydrocarbons having heteroatoms can be further demetallized, desulfurized and denitrogenated by hydrotreating as described above for the first hydrotreatment unit 12. Hydrotreatment reactor 92 may also include hydrotreating catalysts suitable for saturation, hydrodewaxing, and hydroisomerization of aromatic compounds.

When the first hydrotreatment reactor 42 is operated as a mild hydrocracking reactor, the first hydrotreatment reactor 42 can feed up to 20 to 60 volume% of feed, boiling at a point above the diesel boiling range. The product can be converted to boiling below the cut point. The second hydrotreatment reactor 92 can exhibit very low conversion and is used primarily for desulfurization if integrated with mild hydrocracking reactor 42 to meet fuel specifications such as eligibility requirements such as ULSD.

The second hydrotreatment effluent stream in line 94 may be heat exchanged with the second hydrotreatment feed stream in line 90. The second hydrotreatment effluent stream in line 94 is a vapor phase second hydrotreatment comprising a liquid second hydrotreatment effluent stream in bottom line 100 and hydrogen in overhead line 98. To provide the effluent stream, it may be separated in the second cold separator 96. The second cold separator is a pressure just below the pressure of the second hydrotreatment reactor 92 and 46 ° C. to 63 ° C. in view of the pressure drop in order to maintain hydrogen and light gases at overhead and usually liquid hydrocarbons at the bottom. (115 ° F. to 145 ° F.). The aqueous stream may be removed from the boot of the second cold separator 96 in line 102.

A steamy second hydrotreatment effluent stream comprising hydrogen in line 98 may be recycled and added to the makeup hydrogen stream in line 20 upstream of the second compressor. In the " spill-back " embodiment of FIG. 1, the vaporous second hydroprocessed effluent stream comprising hydrogen in line 98 is, at the intersection 25, a first makeup gas compressor ( 22 is added to the makeup hydrogen stream in line 20 upstream. The makeup gas in line 20 and the recycle gas in line 98 are mixed in line 26 and proceed for compression as described above. Thus, the first compressor 22 and the second compressor 32 are in downstream communication with the overhead line 98.

The liquid second hydroprocessing effluent stream in line 100 may be fractionated in fractionation column 104, which may be a stripping column. The liquid second hydrotreatment effluent stream in line 100 may be heated before being fed to the stripping column 104. The liquid second hydrotreatment effluent stream may be stripped in stripping column 104 with steam from line 110 to provide naphtha and light final stream in overhead line 112. The product stream may be recovered in the bottom line 114. In an embodiment, the product stream is a diesel stream comprising less than 50 wppm sulfur based on LSD, and preferably a diesel stream comprising less than 10 wppm sulfur based on ULSD. It can be envisioned that the stripping column 104 can be operated as a fractionation column with a reboiler instead of using stripping steam.

By recycling hydrogen from the second hydroprocessing unit 14 back to the suction side of the first compressor 22, the second hydroprocessing unit can be operated without a recycle gas compressor. Recycle hydrogen from the second hydrotreatment unit 14 is further compressed and used in the first hydrotreatment unit 12.

FIG. 2 shows a "spill forward" of an apparatus and method for recycling a second hydroprocessing effluent stream in vapor phase in line 98 'to a second compressor 24 and using a hot separator upstream of the first cold separator. -forward) embodiment "8 '. Many of the elements in FIG. 2 have the same structure as in FIG. 1 and have the same reference numerals. Elements of FIG. 2 that correspond to the elements in FIG. 1 but with different structures have the same reference numerals as in FIG. 1 but are indicated with a prime symbol '. The embodiment of FIG. 2 differs from the embodiment of FIG. 1 in the compression section 10 ′ and the first hydroprocessing unit 12 ′.

In the compression section 10 ′, the makeup hydrogen stream in the makeup hydrogen line 20 ′ is supplied to a first compressor 22 to raise the pressure of the makeup hydrogen stream and to first compress makeup in line 24 ′. Provide a hydrogen stream. The first compressor 22 may correspond to a series of compressors.

Split 27 ′ on first compressed makeup hydrogen line 24 ′ takes the first portion of compressed makeup hydrogen at first split line 28 ′ and the second portion of compressed makeup hydrogen at second split line. Enable to take at 30 '. The second portion of the compressed makeup hydrogen in the second split line 30 'goes to the second hydroprocessing unit 14. The intersection 25 'between the overhead line 98' and the second split line 28 'that delivers the vaporized second hydroprocessing effluent stream is the overhead line 98' and the first split line ( 28 ') to provide communication. A pressure let-down valve on the first split line 28 'is provided with a second hydrotreatment effluent stream in vapor phase to allow mixing and allowing the two streams in line 26'. The pressure between one compressed makeup hydrogen stream can be equalized.

The mixture of the second portion of compressed makeup hydrogen in the first split line 28 ′ and the second hydroprocessing effluent stream in the vapor phase in line 26 ′ can be further compressed in a second compressor 32. Which may be a series of compressors for providing a second compressed makeup stream in line 34. As a result, the second compressor 32 communicates downstream with the overhead line 98 'which is in bypass communication with the first compressor 22.

The second compressed makeup stream in line 34 may be joined by a recycle hydrogen stream in line 56 to provide a first hydroprocessed hydrogen stream in line 36. The first hydroprocessed hydrogen stream in line 36 taken from the second compressed makeup hydrogen stream is the first hydrocarbon feed stream in line 38 to provide a first hydroprocessed feed stream in line 40. Can join. The remainder of the embodiment of FIG. 2 operates as in FIG. 1 except for the following exceptions.

Compared to the embodiment of FIG. 1, the second difference in the embodiment of FIG. 2 lies in the first hydroprocessing unit 12 ′. The first hydrotreatment unit 12 ′ may utilize a high temperature separator 120 in downstream communication with the first hydroprocessing reactor 42 via line 44 ′, which is provided at overhead line 122. Vapor phase hydrocarbon stream and liquid phase hydrocarbon stream in bottom line (124). The high temperature separator 120 operates at 177 ° C. to 343 ° C. (350 ° F. to 650 ° F.) and preferably at 232 ° C. to 288 ° C. (450 ° F. to 550 ° F.). The high temperature separator may be operated at a pressure slightly lower than the hydrocracking reactor 42 in view of the pressure drop. The vapor phase hydrocarbon stream in line 122 may be cooled prior to entering the first cold separator 46. As a result, the first hydroprocessing effluent in the vapor phase is treated as described above with respect to FIG. 1 and in the vapor phase comprising a liquid hydrocracking effluent in line 52 and hydrogen in line 48. To provide a hydrocracking effluent stream, it may be separated in the first cold separator 46. The first low temperature separator 46 thus communicates downstream with the overhead line 122 of the high temperature separator 120.

Liquid hydrocarbon streams in bottom line 124 may be fractionated in fractionation section 16 ′. In one aspect, the liquid hydrocarbon stream in line 124 is in the hot flash drum 130 to provide a light final stream in overhead line 132 and a heavy liquid stream in lower line 134. Can be flashed. The hot flash drum 130 may be operated at the same temperature as the hot separator 120 but may be operated at a lower pressure of 1.4 MPa to 3.1 MPa (200 to 450 psig) (gauge pressure). The heavy liquid stream in bottom line 134 may be further fractionated in fractionation section 16 ′. In one aspect, the heavy liquid stream in line 134 may be introduced into stripping column 70 at a height lower than the feed point light liquid stream in line 62.

The remainder of the embodiment of FIG. 2 may be the same as already described with respect to FIG. 1, with the exception of the compression section 10 ′ already mentioned. The embodiment of the high temperature separator 120 just described in FIG. 2 may also be used in the embodiment of FIG. 1.

Preferred embodiments of the invention are described herein, including the best mode known to the inventors in practicing the invention. It is to be understood that the examples presented are merely examples and should not be considered as limiting the scope of the invention.

Without further explanation, those skilled in the art will appreciate that, using the above description, the present invention can be used for its widest scope. The above-described preferred specific embodiments are, therefore, to be understood only for the purpose of description and in no way limit the rest of the disclosure in any way.

In the above, all temperatures are stated in degrees Celsius and all ratios and percentages are by weight unless stated otherwise. The pressure is given at the outlet of the vessel, in particular at the vapor outlet in vessels with multiple outlets.

From the above description, those skilled in the art can easily identify the main features of the present invention, and the present invention can be variously modified and modified to suit various applications and conditions without departing from the spirit and scope of the present invention.

8: Apparatus for Generating Diesel
10: compression section
12: first hydroprocessing unit
14: second hydroprocessing unit
16: classification section

Claims (10)

A method for hydrotreating two hydrocarbon streams,
Compressing the makeup hydrogen stream in a first compressor to provide a first compressed makeup hydrogen stream,
Compressing the first portion of the first compressed makeup hydrogen stream in a second compressor to provide a second compressed makeup hydrogen stream,
Taking a second portion of the first compressed makeup hydrogen stream as a second hydrotreated hydrogen stream,
Hydrotreating the first hydrocarbon stream in the presence of a first hydrotreatment hydrogen stream comprising a first hydrotreatment catalyst and a second compressed makeup hydrogen stream to provide a first hydrotreatment effluent stream,
Hydrotreating the second hydrocarbon stream in the presence of a second hydrotreatment hydrogen stream comprising a second hydrotreatment catalyst and a first compressed makeup hydrogen stream to provide a second hydrotreatment effluent stream,
Separating the second hydrotreatment effluent stream to provide a vaporous second hydrotreatment effluent stream, and
Adding a vaporized second hydrotreatment effluent stream to the makeup stream upstream of the first compressor
≪ / RTI > The process of claim 1, wherein the first hydrotreatment hydrogen stream is hydrocracked in the presence of a hydrocracking catalyst and the second hydrotreatment hydrogen stream is hydrotreated in the presence of a hydrotreating catalyst. The method of claim 1,
Fractionating at least a portion of the first hydrotreatment effluent stream to provide said second hydrocarbon stream that is a diesel stream
≪ / RTI > The method of claim 1,
Separating the first hydroprocessing effluent stream into a liquid first hydroprocessing effluent stream and a vaporous first hydroprocessing effluent stream comprising hydrogen,
Compressing the vaporous first hydrotreatment effluent stream to provide a recycle hydrogen stream, and
Adding a second compressed makeup hydrogen stream to the recycle hydrogen stream or to the vaporous first hydrotreatment effluent stream to provide the first hydrotreated hydrogen stream.
≪ / RTI > The method of claim 1,
Separating the second hydrotreatment effluent stream into a liquid second hydrotreatment effluent stream, and
Further fractionating the liquid second hydroprocessing effluent stream to provide low sulfur diesel
≪ / RTI > An apparatus for hydrotreating two hydrocarbon streams,
Makeup hydrogen line for carrying makeup hydrogen stream,
A first compressor in communication with the makeup hydrogen line for compressing the makeup hydrogen stream to provide a first compressed makeup hydrogen stream;
A split in communication with the first compressor to separate the first compressed makeup hydrogen stream into a first portion in a first split line and a second portion in a second split line,
A second compressor in communication with the first split line for compressing the first portion of the first compressed makeup hydrogen stream to provide a second compressed makeup hydrogen stream in a second compressed makeup hydrogen line,
A first hydrotreatment reactor in communication with the first split line for hydrotreating a first hydrocarbon stream,
A second hydroprocessing reactor in communication with the second split line for hydrotreating a second hydrocarbon stream, and
A separator in communication with the second hydroprocessing reactor to separate the second hydroprocessing effluent stream into a vaporous second hydroprocessing effluent stream comprising hydrogen in an overhead line.
Wherein the second compressor is in communication with the overhead line. 7. The apparatus of claim 6, wherein the first compressor is in communication with the overhead line at the intersection on the makeup hydrogen line. The method according to claim 6,
The second hydrotreatment reactor to separate a second hydrotreatment effluent stream into a liquid second hydrotreatment effluent stream in the bottom line and a vaporous second hydrotreatment effluent stream comprising hydrogen in the overhead line. Cold separator in communication with
Wherein the second compressor is in communication with the overhead line at an intersection on the second split line. The apparatus of claim 6, wherein the first hydrotreating reactor is a hydrocracking reactor and the second hydrotreating reactor is a hydrotreating reactor. The method according to claim 6,
Fractionation line in communication with a bottom line for fractionating the liquid second hydroprocessing effluent stream to diesel
Lt; / RTI >

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