Process for hydrotreating biorenewable feedstock

Abstract

A method for hydrotreating a biorenewable feedstock is disclosed. The process includes hydrotreating the bioregenerable feed stream in a hydrotreating reactor to hydrodeoxygenate the bioregenerable feed stream to provide a hydrotreated stream. A hydrocracking feed stream taken from the hydrotreated stream is hydrocracked in a hydrocracking reactor to provide a hydrocracked stream. A hydroisomerization feed stream taken from the hydrotreated stream is hydroisomerized in a hydroisomerization reactor to provide a hydroisomerized stream. The hydroisomerized stream is separated to provide a jet fuel stream and a diesel stream. The diesel stream is separated into a first recycled diesel stream and a second recycled diesel stream. The first recycle diesel stream is passed to a hydrocracking reactor and the second recycle diesel stream is passed to a hydroisomerization reactor.

Description

Technical Field

[0001] This art relates to methods for the hydrogenation of biorenewable feedstocks. Particularly relevant to this art are methods for the hydrogenation of biorenewable feedstocks using recycled diesel streams. Background Technology

[0002] With increasing global demand for fuels, the production of fuels from sources other than crude oil and the blending of components from sources other than crude oil are gaining increasing attention. These sources are often referred to as biorenewable sources and include, but are not limited to, vegetable oils such as corn oil, rapeseed oil, low-erucic acid rapeseed oil, and soybean oil; microbial oils such as algal oil; animal fats such as inedible tallow; fish oil; and various waste streams such as yellow and brown greases and sewage sludge. A common characteristic of these sources is that they consist of triglycerides and free fatty acids (FFAs). Both triglycerides and FFAs contain aliphatic carbon chains with approximately 8 to approximately 24 carbon atoms. The aliphatic carbon chains in triglycerides or FFAs can be fully saturated or mono, di, or polyunsaturated.

[0003] Hydrogenation can include methods of converting hydrocarbons into more valuable products in the presence of a hydrogenation catalyst and hydrogen. Hydrotreating is a method of contacting hydrocarbons with hydrogen in the presence of a hydrogenation catalyst, which is primarily used to remove heteroatoms such as sulfur, nitrogen, oxygen, and metals from hydrocarbon feedstocks. In hydrogenation, hydrocarbons with double and triple bonds, such as alkenes, can be saturated.

[0004] The production of hydrocarbon products within the boiling range of diesel can be achieved through hydrotreating biorenewable feedstocks. Hydrotreating can deoxygenate oxygenated hydrocarbons, including decarboxylation and decarbonylation. Following hydrotreating, hydroisomerization can be performed to improve the cold-flow properties of the resulting diesel and jet fuel. Hydroisomerization, or hydrodewaxing, is a hydrogenation process that increases alkyl branching on the hydrocarbon backbone in the presence of hydrogen and a hydroisomerization catalyst to improve the cold-flow properties of the hydrocarbon. Hydroisomerization includes the hydrodewaxing discussed herein.

[0005] Hydrocracking is a hydrogenation process in which hydrocarbons are cracked into lower molecular weight hydrocarbons in the presence of hydrogen and a hydrocracking catalyst. Depending on the desired output, a hydrocracking unit may contain one or more identical or different catalyst beds.

[0006] As refineries seek to increase their capacity to process biorenewable feedstocks, they are looking for methods to produce larger volumes of jet fuel due to their high value and demand. Methods are needed for producing diesel fuel from biorenewable feedstocks and for increasing jet fuel production. Summary of the Invention

[0007] The method produces a diesel fuel stream from a biorenewable feedstock by hydrotreating it to remove heteroatoms and hydroisomerizing it to improve its cold flow properties. The diesel fuel stream can then be hydrocracking to provide jet fuel range materials. The method produces jet fuel range materials that meet jet fuel specifications without affecting or impairing jet fuel yield. Attached Figure Description

[0008] Figure 1 This is a simplified process flow diagram of a method for hydrogenating biorenewable feedstocks according to this disclosure.

[0009] Figure 2 It is a graph plotted between fuel yield and % of recirculated diesel feed according to an exemplary embodiment of this disclosure.

[0010] Figure 3 It is a graph plotted between the fuel pour point and a percentage of the recirculated diesel feedstock according to another exemplary embodiment of this disclosure.

[0011] Figure 4 It is a graph plotted between fuel density and % of recirculated diesel feed according to another exemplary embodiment of this disclosure.

[0012] definition

[0013] The term "connectivity" means that material flow is operatively permitted between enumerated components.

[0014] The term "downstream connectivity" means that in downstream connectivity at least a portion of the material flowing toward the main body can be operatively flowed from the object with which it is connected.

[0015] The term "upstream connectivity" means that at least a portion of the material flowing out of the main body in an upstream connectivity can be operatively flowed to the object connected to it.

[0016] The term "direct connection" means that the flow from the upstream component enters the downstream component without passing through fractionation or conversion units, and the composition does not change due to physical fractionation or chemical conversion.

[0017] The term "indirect connection" means that the flow from the upstream component enters the downstream component after passing through the fractionation or conversion unit, and the composition changes due to physical fractionation or chemical conversion.

[0018] The term "bypass" means that an object is disconnected from the downstream entity at least within the scope of the bypass.

[0019] The term "tower" refers to one or more distillation columns used to separate one or more components with different volatility. Unless otherwise specified, each column includes a condenser at the top of the column for condensing a portion of the overhead feed and returning it to the top of the column, and a reboiler at the bottom of the column for vaporizing a portion of the bottom feed and returning it to the bottom of the column. The feed to the column can be preheated. The top pressure is the pressure of the vapor at the top of the column at the vapor outlet. The bottom temperature is the liquid temperature at the bottom outlet. Top and bottom lines refer to the net lines from any downstream reflux or reboiler to the column. Stripper columns may omit the reboiler at the bottom of the column, instead providing the heating requirements and separation power for a liquefied inert medium such as steam. Stripper columns typically feed from the top tray and remove the main product from the bottom.

[0020] As used herein, the term "rich feed stream" means that the rich feed stream exiting the container has a higher component concentration than the feed entering the container.

[0021] As used herein, the term "lean component stream" means that the lean component stream exiting the container has a lower component concentration than the feed into the container.

[0022] As used herein, the term “boiling point temperature” refers to the atmospheric equivalent boiling point (AEBP) calculated from the observed boiling temperature and distillation pressure, as provided in ASTM D86 or ASTM D2887.

[0023] As used herein, the term “true boiling point” (TBP) refers to a test method conforming to ASTM D-2892 for determining the boiling point of a substance. ASTM D-2892 is used to produce standardized masses of liquefied gases, distillate fractions, and residues for which analytical data are available, and to determine the yield of the aforementioned fractions by both mass and volume, based on which a graph of distillation temperature versus mass% is obtained using fifteen theoretical plates in a column with a reflux ratio of 5:1.

[0024] As used herein, the terms “T5” or “T95” refer to the boiling temperature of a 5% or 95% mass percentage sample obtained using ASTM D-86 or TBP (as applicable).

[0025] As used in this article, the term “initial boiling point” (IBP) refers to the temperature at which a sample begins to boil using ASTM D2887, ASTM D-86, or TBP (as applicable).

[0026] As used herein, the term “endpoint” (EP) refers to the temperature at which a sample is brought to a complete boil using ASTM D2887, ASTM D-86, or TBP (as applicable).

[0027] As used herein, the term "jet fuel range material" refers to hydrocarbons boiled in the range of IBP (Impulse Blasting Point) between about 85°C (185°F) and about 135°C (275°F) or T5 (T5) between about 110°C (230°F) and about 160°C (320°F) using the TBP distillation method, and the "recycle fractionation point" includes T95 between about 295°C (563°F) and about 315°C (599°F). Hydrocarbons exceeding the "recycle fractionation point" and reaching the "diesel fractionation point" including T95 between about 343°C (650°F) and about 399°C (750°F) are "diesel boiling range" materials using the TBP distillation method.

[0028] As used herein, the term “conversion rate” refers to the ratio of products with boiling points below the recycling fractionation point to feed with boiling points at or above the recycling fractionation point.

[0029] As used herein, the term "separator" refers to a vessel having an inlet and at least one top vapor outlet and a bottom liquid outlet, and may also have an outlet for an aqueous feed stream from a boot. A flash tank is a type of separator that can be connected downstream to a separator capable of operating at higher pressures.

[0030] As used herein, the terms “major” or “most” mean greater than 50%, appropriately greater than 75%, and preferably greater than 90%.

[0031] As used in this article, the term "C" x "This should be understood as referring to a molecule having the number of carbon atoms indicated by the subscript "x". Similarly, the term "C" x "-" refers to a molecule containing x carbon atoms or less, and preferably x and fewer. The term "C" x "+" refers to a molecule that has x or more carbon atoms, and preferably x and more.

[0032] As used in this article, the term "carbon number" refers to the number of carbon atoms in each hydrocarbon molecule, and typically in alkane molecules. Detailed Implementation

[0033] With increasing emphasis on the environment and a sustainable economy, it is becoming increasingly attractive for refineries to produce green fuels from Renewable Identifiers (RINs) counted according to the Renewable Fuels Standard Procedure as part of their portfolios to maximize profitability. RINs are credits used for compliance and can be traded within the procedure to enhance profitability. This disclosure enables refineries to produce jet fuel that meets jet fuel specifications without compromising the jet fuel yield of the method.

[0034] exist Figure 1According to an exemplary embodiment, a method 101 for hydrogenating a biorenewable feedstock is shown. The method for hydrogenating a biorenewable feedstock includes a hydrotreating section 111 and a hydrogenation section 131. A feed line 102 delivers a feed stream of fresh biorenewable feedstock to the hydrotreating section 111. The biorenewable feedstock may be blended with a mineral feed stream, but preferably comprises the majority or all of the biorenewable feedstock. The mineral feedstock is a conventional feedstock derived from crude oil extracted from underground. The biorenewable feedstock may have a nitrogen concentration of about 50 wppm to about 800 wppm. The biorenewable feedstock may have a high oxygen content of up to 10% by weight or higher. The biorenewable feedstock may also contain sulfur of about 1 wppm to about 500 wppm, typically not exceeding about 200 wppm.

[0035] A variety of different biorenewable feedstocks can be used in method 101. The term "biorenewable feedstock" is intended to include feedstocks other than those obtained from crude oil. Biorenewable feedstocks may include any of those feedstocks containing at least one glyceride and a free fatty acid. Most glycerides are triglycerides, but monoglycerides and diglycerides may also be present and processed. Free fatty acids may be obtained from phospholipids, which can provide phosphorus in the feedstock. Examples of such biorenewable feedstocks include, but are not limited to, linseed oil, low-erucic acid rapeseed oil, corn oil, soybean oil, rapeseed oil, soybean oil, rapeseed oil, tallow, sunflower oil, hemp seed oil, olive oil, linseed oil, coconut oil, castor oil, peanut oil, palm oil, mustard oil, tallow, yellow and brown fats, lard, whale oil, fats in milk, fish oil, algal oil, sewage sludge, etc. Additional examples of biorenewable feedstocks include non-edible vegetable oils from the group comprising: Jatropha curcas (Ratanjot, Wild Castor, Jangli Erandi), Madhuca indica (Mohuwa), Pongamia pinnata (Karanji, Honge), Calophyllum inophyllum, Moringa oleifera, and Azadirachta indica (Neem). Typical plant or animal fats contain triglycerides and FFAs in their structures comprising aliphatic hydrocarbon chains having about 8 to about 30 carbon atoms. As will be understood, biorenewable feedstocks may include one or more mixtures of the foregoing examples. Biorenewable feedstocks may be pretreated to remove contaminants and filtered to remove solids.

[0036] The bioregenerative feed stream in feed line 102 can flow from the feed buffer tank to the hydrotreating section 111. According to this disclosure, the hydrotreating section 111 may include a guard bed reactor 110 and a hydrotreating reactor 120. The bioregenerative feed stream in feed line 102 may be combined with the hydrogen stream in line 103 to provide a combined bioregenerative feed stream in line 104. The combined bioregenerative feed stream in line 104 is then passed to the guard bed reactor 110. Alternatively, the bioregenerative feed stream in feed line 102 and the hydrogen stream in line 103 may be passed separately to the guard bed reactor 110. In one aspect, the bioregenerative feed stream in feed line 102 may include a heated bioregenerative feed stream.

[0037] The guard bed temperature of the guard bed reactor 110 can be between about 246°C (475℉) and about 343°C (650℉) or between about 288°C (550℉) and about 304°C (580℉). The guard bed reactor 110 is operated low enough to prevent olefin polymerization in the FFA, but high enough to promote olefin saturation, hydrodemetallization, hydrodeoxygenation (including hydrodecarbonylation and hydrodecarboxylation), hydrodesulfurization, and hydrodenitrogenation reactions.

[0038] The guard bed may contain a base metal on a support. Base metals that can be used in this process include non-precious metals, nickel, chromium, molybdenum, and tungsten. Other base metals that can be used include tin, indium, germanium, lead, cobalt, gallium, and zinc. The process may also use metal sulfides, wherein the metal in the metal sulfide is selected from one or more of the listed base metals. The biorenewable feedstock may be loaded through the base metal catalyst at a pressure of 1379 kPa (abs) (200 psia) to 6895 kPa (abs) (1000 psia). In another embodiment, the guard bed catalyst may contain a second metal, wherein the second metal includes one or more of the following metals: tin, indium, ruthenium, rhodium, rhenium, osmium, iridium, germanium, lead, cobalt, gallium, zinc, and thallium. A nickel-molybdenum catalyst on alumina may be a suitable catalyst in the guard bed reactor 110. Multiple guard beds may be included in the guard bed reactor 110, such as two, three, or more. The hydrogen quenching material flow from the hydrogen quenching line 106 can be injected at the bed position to control the temperature exothermic reaction.

[0039] The contact biorenewable feed stream is discharged from the guard bed reactor 110 via contact feed line 112. In the guard bed reactor 110, most of the hydrodemetallization and hydrodeoxygenation (including hydrodecarbonylation and hydrodecarboxylation) reactions occur along with some hydrodenitrogenation and hydrodesulfurization. The removed metals include alkali metals, alkaline earth metals, and phosphorus. The contact biorenewable feed stream in line 112 is then transferred to the hydrotreatment reactor 120.

[0040] On one hand, the contacted biorenewable feed stream in line 112 can be heated to increase its temperature before being passed to the hydrotreating reactor 120. The heated, contacted biorenewable feed stream is then fed into the hydrotreating reactor 120 of the hydrotreating reactor section 111.

[0041] In the hydrotreating reactor 120, under hydrotreating conditions, a heated, contacting biorenewable feed stream in line 112 is brought into contact with a hydrotreating catalyst in the presence of hydrogen to saturate the olefins or unsaturated portions of the n-alkane chains in the biorenewable feedstock. The hydrotreating catalyst also catalyzes hydrodeoxygenation reactions, including hydrodecarboxylation and hydrodecarbonylation, to remove oxygen-containing functional groups from hydrocarbon molecules in the biorenewable feedstock, which are then converted into water and carbon oxides. The hydrotreating catalyst also catalyzes the hydrodesulfurization of organic sulfur and the hydrodenitrification of organic nitrogen in the biorenewable feedstock. Essentially, the hydrotreating reaction removes heteroatoms from hydrocarbons and saturates the olefins in the feed stream.

[0042] The hydrotreating catalyst can be disposed in one, two, or more beds. The hydrotreating hydrogen quenching feed stream from the hydrotreating hydrogen quenching line 121 can be transferred at an inter-bed location within the hydrotreating reactor 120. In an exemplary embodiment, Figure 1 Two hydrotreatment catalyst beds are shown. However, the hydrotreatment reactor 120 may include more than two catalyst beds or a single hydrotreatment catalyst bed.

[0043] Hydrotreating catalysts may include nickel, nickel and molybdenum, or cobalt and molybdenum, dispersed on a high surface area support such as alumina. Other catalysts include one or more noble metals dispersed on a high surface area support. Non-limiting examples of noble metals include platinum and / or palladium dispersed on an alumina support such as γ-alumina. Suitable hydrotreating catalysts include BDO 200, BDO 300, or BDO 400, available from UOP LLC, Des Plaines, Illinois. The hydrotreating reaction temperature may range from about 343°C (650°F) to about 427°C (800°F), and preferably from about 349°C (690°F) to about 400°C (752°F). Typically, hydrotreating conditions involve pressures from about 700 kPa (100 psig) to about 21 MPa (3000 psig).

[0044] A hydrotreatment feed stream comprising a hydrocarbon fraction with a significant concentration of n-alkane is produced in the hydrotreatment line 122 of the hydrotreatment reactor 120 from the hydrotreatment reactor section 111. The concentration of oxygenated compounds in the hydrocarbon fraction is essentially zero, while the olefin concentration is significantly reduced relative to the contacting biorenewable feed stream. The concentration of organic sulfur in the hydrocarbon fraction does not exceed 500 W ppm, and the concentration of organic nitrogen in the hydrocarbon fraction is less than 10 W ppm.

[0045] The hydrotreatment stream in hydrotreatment line 122 can be separated to provide a hydrotreatment vapor stream and a hydrotreatment liquid stream, the hydrotreatment liquid stream having a lower oxygen concentration than the bioregenable feed stream 102. In one aspect, the hydrotreatment stream in hydrotreatment line 122 can be passed to separation section 123 to provide a hydrotreatment vapor stream in line 124 and a hydrotreatment liquid stream in line 126, the hydrotreatment liquid stream having a lower oxygen concentration than the bioregenable feed stream 102. In an exemplary embodiment, separation section 123 may include a separator, one or more additional separators, and / or a stripping tower. According to this disclosure, the hydrotreatment vapor stream in line 124 can be extracted and processed to provide one or more of the hydrogen stream in line 103, the hydrogen quenching stream in line 106, and the hydrotreatment hydrogen quenching stream in line 121. The liquid stream from the separation section 123 can be recycled to the hydrotreating reactor 120 and / or the hydrotreating section 111.

[0046] Desired products (such as transportation fuels) can be recovered or separated from the hydrotreated liquid stream in line 126. However, the hydrotreated liquid stream in line 126 contains a high concentration of n-alkanes and will have poor cold flow properties. Therefore, to improve the cold flow properties, the hydrotreated liquid stream in line 126 can be transferred to a hydrogenation treatment section 131. According to this disclosure, the hydrogenation treatment section 131 includes a hydrocracking reactor and a hydroisomerization reactor. In the hydrogenation treatment section 131, the hydrotreated liquid stream in line 126 can be contacted with a hydroisomerization catalyst under hydroisomerization conditions in the hydroisomerization reactor to hydroisomerize n-alkanes to branched alkanes.

[0047] In one aspect, the hydrocracking reactor 130a and the hydroisomerization reactor 130b are located in a single vessel. In an exemplary embodiment, the hydrogenation treatment section 131 includes a hydrogenation treatment reactor 130, which includes the hydrocracking reactor 130a and the hydroisomerization reactor 130b.

[0048] Typically, methods for producing jet fuel-range materials include a single reactor for hydroisomerization of deoxygenated products from a hydrotreatment reactor. Additionally, an unconverted recycle stream, which may contain a recycle diesel feed stream, can be fed together with the hydrotreated liquid feed stream to a hydrotreatment reactor 130 for hydroisomerization.

[0049] exist Figure 1 In an embodiment where a hydrocracking reactor 130a and a hydroisomerization reactor 130b are stacked, the temperature of the hydroisomerization reactor 130b is determined by the activity of the hydroisomerization catalyst required to achieve jet fuel specifications, which may be the target pour point specifications of the jet fuel. However, the high-temperature operation of the hydrocracking catalyst results in a loss of C200 in the jet fuel range material due to hydrocracking. 9- Materials. Therefore, the yield of jet fuel range materials meeting desired specifications may be reduced. This disclosure provides a method for managing the feed into a hydrocracking catalyst and the jet fuel range materials produced by the method. The method includes a dual-feed injection with variable liquid hourly space velocity (LHSV) to selectively regulate the flow rate of a recirculated diesel feed stream entering a hydrocracking catalyst reactor 130a or a hydrocracking catalyst bed 135a located within the hydrocracking catalyst reactor 130a to produce a jet fuel range material meeting given density, pour point, or viscosity specifications without compromising jet fuel yield. The disclosed method, having a stacked configuration for the hydrocracking reactor 130a or hydrocracking catalyst bed 135a and a hydroisomerization reactor 130b or hydroisomerization catalyst bed 135b, produces jet fuel meeting jet fuel specifications as specified in ASTM D7566. The method controls the proportion of the recirculated diesel feed stream delivered to the hydrocracking catalyst, rather than feeding the entire recirculated diesel feed stream to the hydrocracking catalyst. On the one hand, the LHSV of the hydrocracking reactor 130a is higher than or equal to the LHSV of the hydroisomerization reactor 130b.

[0050] The method of this invention measures one or more of the density and viscosity of the jet fuel produced by the method, and compares the measured values ​​of one or more of the density and viscosity with corresponding setpoint values. Based on the comparison, the recycled diesel feed stream is divided into two parts, one part of which is proposed to be mixed with the hydrotreated liquid feed stream in line 126 and delivered to hydrocracking reactor 130a or hydrocracking catalyst bed 135a located in hydrocracking catalyst reactor 130a. The other part or the remainder of the recycled diesel feed stream is delivered to the inlet of downstream hydroisomerization reactor 130b or hydroisomerization catalyst bed 135b located in hydroisomerization reactor 130b. This method helps to maintain a high jet fuel yield and minimize the cracking of jet fuel range material to C9- material.

[0051] Referring to hydrogenation section 131, the hydrotreated liquid feed stream in line 126 is passed to hydrocracking reactor 130a. According to this disclosure, a first diesel recirculation feed stream in line 182 is also passed to hydrocracking reactor 130a. In an exemplary embodiment, the first diesel recirculation feed stream in line 182 and the hydrotreated liquid feed stream in line 126 are combined or mixed to provide the hydrogenation feed stream in line 128. The hydrogenation feed stream in line 128 is passed to hydrocracking reactor 130a. The hydrocracking hydrogen feed stream in line 129 is also passed to hydrocracking reactor 130a. In an embodiment, the hydrogenation feed stream in line 128 is combined with the hydrocracking hydrogen feed stream in line 129 to provide the combined hydrogenation feed stream in line 132. The combined hydrogenation feed stream in line 132 is transferred to hydrocracking reactor 130a.

[0052] The hydrocracking reactor 130a can be a fixed-bed reactor, which may include single or multiple catalyst beds, and various combinations of hydrocracking catalysts in one or more vessels. The hydrocracking reactor 130a can be operated in conventional continuous gas-phase, moving-bed, or fluidized-bed hydrogenation reactors. In the presence of a hydrocracking hydrogen feed stream, a hydrotreated liquid feed stream and a first recirculated diesel feed stream are hydrogenated on the hydrocracking catalyst in the hydrocracking reactor 130a to provide the hydrocracking feed stream.

[0053] The hydrocracking reactor 130a can provide at least about 20 vol% and typically more than about 60 vol% of the first recirculated diesel feed to a total conversion of products in the diesel range with boiling points below about 293°C (560°F) to about 310°C (590°F). The hydrocracking reactor 130a can operate based on the total conversion at a partial conversion of more than about 30 vol% of the feed or at least about 90 vol% of the complete conversion. The hydrocracking reactor 130a can operate under mild hydrocracking conditions, which will provide a total conversion of about 20 vol% to about 60 vol%, preferably about 20 vol% to about 50 vol%, of the products in the hydrocracking feed to a boiling point below the diesel boiling point range.

[0054] Hydrocracking catalysts can utilize amorphous silica-alumina or zeolite-based feedstocks in combination with one or more Group VIII or Group VIB metal hydride components to selectively produce a balance of light diesel and jet fuel distillates. Alternatively, catalysts typically comprising any crystalline zeolite cracking feedstock on which Group VIII metal hydride components are deposited can be suitable. Additional hydride components can be selected from Group VIB to combine with the zeolite feedstock.

[0055] Zeolite cracking substrates, sometimes referred to in the art as molecular sieves, are typically composed of silica, alumina, and one or more exchangeable cations (such as sodium, magnesium, calcium, and rare earth metals). They are also characterized by relatively uniform pore sizes between about 4 angstroms and about 14 angstroms. Preferably, zeolites with a relatively high silica / alumina molar ratio (between about 3 and about 12) are used. Suitable zeolites found in nature include, for example, mordenite, zeolite, flaky zeolite, magnesia-alkali zeolite, cycloid zeolite, chalcogenide, buergerianite, and octahedral zeolite. Suitable synthetic zeolites include, for example, B, X, Y, and L crystal types, such as synthetic octahedral zeolite and mordenite. Preferred zeolites are those with pore sizes between about 8 angstroms and 12 angstroms, wherein the silica / alumina molar ratio is about 4 to 6. An example of a zeolite falling into the preferred group is synthetic Y molecular sieve.

[0056] Naturally occurring zeolites are typically found in sodium, alkaline earth metal, or mixed forms. Synthetic zeolites are almost always prepared in sodium form. In any case, for use as a cracking matrix, it is preferable that most or all of the original zeolite monovalent metals are ion-exchanged with polyvalent metals and / or with ammonium salts, followed by heating to decompose the ammonium ions associated with the zeolite, thereby leaving hydrogen ions and / or exchange sites at their locations, effectively removing cations through further water removal. This property of hydrogen, or "cation-removed" Y zeolite, is described more specifically in US 3,100,006.

[0057] Mixed multivalent metal-hydrogen zeolites can be prepared by exchanging ions with ammonium salts, followed by partial reverse exchange with multivalent metal salts, and then calcination. In some cases, such as in the synthesis of mordenite, the hydrogen form can be prepared by direct acid treatment of alkali metal zeolites. In one aspect, preferred cracking substrates are those based on an initial ion exchange capacity lacking at least about 10 wt% and preferably at least about 20 wt% of metal cations. In another aspect, a desirable and stable class of zeolites is those in which hydrogen ions satisfy an ion exchange capacity of at least 20 wt%.

[0058] The active metal used as the hydride component in the preferred hydrocracking catalyst of this disclosure is a Group VIII active metal, namely iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, and platinum. In addition to these metals, other promoters, including Group VIB metals such as molybdenum and tungsten, may be used in combination. The amount of hydride metal in the catalyst can vary over a wide range. Broadly speaking, any amount between about 0.05 wt% and about 30 wt% can be used. Regarding noble metals, it is generally preferred to use about 0.05 wt% to about 2 wt% of noble metals. Noble metals are preferably used as hydride metals on the hydrocracking catalyst to provide selectivity for jet fuels because hydrogen sulfide and ammonia, which could deactivate the noble metal catalyst, have been removed upstream of the process.

[0059] The method of incorporating metal hydrides involves contacting the base material with an aqueous solution containing a suitable compound of the desired metal, wherein the metal exists in the form of a cation. After adding one or more selected metal hydrides, the resulting catalyst powder is then filtered, dried, and pelletized as needed with added lubricants, binders, etc., and calcined in air at a temperature, for example, from about 371°C (700°F) to about 648°C (1200°F) to activate the catalyst and decompose ammonium ions. Alternatively, the base material component can be pelletized, and then the hydride component can be added and activated by calcination.

[0060] The catalysts described above can be used undiluted, or powdered catalysts can be mixed with other relatively less active catalysts, diluents, or binders such as alumina, silica gel, silica-alumina cogel, activated clay, etc., in a proportion ranging from about 5% to about 90% by weight and co-prepared into pellets. These diluents can be used as is, or they may contain a small proportion of added hydride metals, such as Group VIB and / or Group VIII metals. Additional metal-promoted hydrocracking catalysts can also be used in the methods of this disclosure, including, for example, aluminum phosphate molecular sieves, crystalline chromosilicates, and other crystalline silicates. Crystalline chromosilicates are described more fully in US 4,363,178.

[0061] DI-100, available from Universal Oil Products Inc. in Des Plaines, Illinois, is a suitable hydrocracking catalyst.

[0062] By means of a method, hydrocracking conditions may include a temperature of about 290°C (550°F) to about 468°C (875°F), preferably 300°C (572°F) to about 445°C (833°F), a pressure of about 2.7 MPa (gauge pressure) (400 psig) to about 20.7 MPa (gauge pressure) (3000 psig), and a 0.4 hr -1 to less than approximately 20 hours -1 LHSV, and approximately 253 Nm 3 / m 3 (1,500 scf / bbl) to approximately 2,527 Nm 3 / m 3 Hydrogen rate of oil (15,000 scf / bbl).

[0063] The hydrocracking feed stream can exit the hydrocracking reactor 130a. In an embodiment, the hydrocracking feed stream can be fed directly into the hydroisomerization reactor 130b. According to this disclosure, the second recirculated diesel feed stream in line 184, together with the hydrocracking feed stream from the hydrocracking reactor 130a, is passed to the hydroisomerization reactor 130b. The hydroisomerization hydrogen feed stream in line 133 is also passed to the hydroisomerization reactor 130b. The hydrocracking feed stream and the second recirculated diesel feed stream in line 184 can be hydroisomerized in the presence of the hydroisomerization hydrogen feed stream via a hydroisomerization catalyst.

[0064] Hydroisomerization (including hydrodewaxing) of n-hydrocarbons in hydroisomerization reactor 130b can be accomplished via one or more hydroisomerization catalyst beds, and hydroisomerization can be operated in a co-current mode. Fixed bed, trickle bed downflow, or fixed bed liquid immersion upflow modes are all suitable. Supplemental hydrogen quenching feed stream can be provided to hydroisomerization reactor 130b for inter-bed quenching.

[0065] Suitable hydroisomerization catalysts may comprise metals of Group VIII (IUPAC 8-10) of the periodic table and a support material. Suitable Group VIII metals include platinum and palladium, each of which may be used alone or in combination. Hydroisomerization catalysts may comprise non-noble metals that are insensitive to sulfur deactivation in acidic environments. Examples of suitable non-noble metals include Ni, Mo, Co, W, Mn, Cu, Zn, or Ru. Mixtures of hydride metals, such as Co / Mo, Ni / Mo, and Ni / W, may also be used. The amount of one or more hydride metals may range from 0.1 wt% to 5 wt% based on the catalyst weight. Methods for loading metals onto a support material include, for example, impregnating the support material with a metal salt of the hydride component and heating. Catalyst support materials containing hydride metals may also be sulfided before use.

[0066] The support material can be amorphous or crystalline. Suitable support materials include amorphous alumina, amorphous silica-alumina, magnesium alkali zeolite, ALPO-31, SAPO-11, SAPO-31, SAPO-37, SAPO-41, SM-3, MgAPSO-31, FU-9, NU-10, NU-23, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-50, ZSM-57, MeAPO-11, MeAPO- 31. MeAPO-41, MgAPSO-11, MgAPSO-31, MgAPSO-41, MgAPSO-46, ELAPO-11, ELAPO-31, ELAPO-41, ELAPO-11, ELAPO-31, ELAPO-11, ELAPO-31, ELAPO-41, zeolite, nepheline, pyroxene, zeolite in hydrogen form, mordenite in magnesium or calcium form, and calcite in magnesium or calcium form, each of which may be used alone or in combination. ALPO-31 is described in US4,310,440. SAPO-11, SAPO-31, SAPO-37, and SAPO-41 are described in US4,440,871. SM-3 is described in US4,943,424, US5,087,347, US5,158,665, and US5,208,005. MgAPSO is MeAPSO, an acronym for metallic aluminum phosphosilicate molecular sieves, where the metallic Me is magnesium (Mg). Suitable MgAPSO-31 catalysts include MgAPSO-31. MeAPSO is described in US 4,793,984, while MgAPSO is described in US 4,758,419. MgAPSO-31 is the preferred MgAPSO, where 31 refers to MgAPSO having a structural type of 31. Many natural zeolites initially having reduced pore size (such as magnesium alkali zeolite) can be converted to forms suitable for olefin skeletal isomerization to produce essentially hydrogen forms by ammonium ion exchange and calcination to remove the associated alkali or alkaline earth metals, as taught in US 4,795,623 and US 4,924,027. Other catalysts and conditions for skeletal isomerization are disclosed in US 5,510,306, US 5,082,956 and US 5,741,759. The hydroisomerization catalyst may also include a modifier selected from lanthanum, cerium, praseodymium, neodymium, samarium, gadolinium, terbium, and mixtures thereof, as described in US5,716,897 and US5,851,949.Other suitable support materials include ZSM-22, ZSM-23, and ZSM-35, which are described for dewaxing in US 5,246,566 and in the article “New Molecular Sieve Process for Lube Dewaxing by Wax Isomerization,” 2 Microporous Materials 439-449 (1994) by SJ Miller. US 5,444,032 and US 5,608,968 teach suitable bifunctional catalysts composed of amorphous silica-alumina gel and one or more metals belonging to Group VIIIA, and are effective for the hydroisomerization of long-chain n-alkanes containing more than 15 carbon atoms. US5,981,419 and US5,908,134 teach a suitable bifunctional catalyst comprising: (a) a porous crystalline material isomorphous to a β-zeolite selected from borosilicates (BOR-B) and borosilicates (Al-BOR-B), wherein the molar ratio of SiO2:Al2O3 is greater than 300:1; and (b) one or more metals belonging to Group VIIIA, selected from platinum and palladium, in an amount ranging from 0.05 wt% to 5 wt%. V. Calemma et al., Applied Catalysis A: Overview (App. Catal. A: Gen.), 190 (2000), 207, teach another suitable catalyst. Alumina or silica can be added to the support material.

[0067] DI-200, available from Universal Oil Products Inc. in Des Plaines, Illinois, is a suitable hydroisomerization catalyst.

[0068] Hydroisomerization conditions typically include temperatures from about 150°C (302°F) to about 450°C (842°F) and pressures from about 1724 kPa (absolute) (250 psia) to about 13.8 MPa (absolute) (2000 psia). In another embodiment, hydroisomerization conditions include temperatures from about 300°C (572°F) to about 360°C (680°F) and pressures from about 3102 kPa (absolute) (450 psia) to about 6895 kPa (absolute) (1000 psia).

[0069] The hydroisomerization feed from hydroisomerization reactor 130b in hydroisomerization line 134 is a branched-chain alkanes-rich feed. The term "rich" means that the effluent has a higher concentration of branched-chain alkanes than the feed entering hydroisomerization reactor 130b, and preferably contains more than 50% by mass of branched-chain alkanes in total alkane content. It is envisioned that the hydroisomerization effluent may contain 80%, 90%, or 95% by mass of branched-chain alkanes in total alkane content. The hydroisomerization conditions in hydroisomerization reactor 130b are selected to avoid undesirable cracking; therefore, the main product in the hydroisomerization feed from hydroisomerization line 134 is branched-chain alkanes. By avoiding undesirable hydrocracking, the hydroisomerization feed from hydroisomerization line 134 will have the same carbon number composition as the feed entering hydroisomerization reactor 130b. For example, although the feed to the hydroisomerization reactor 130b may contain 8% by weight of alkanes with four carbon atoms, the hydroisomerization stream will also contain 8% by weight of alkanes with four carbon atoms, although the hydroisomerization stream will have a larger proportion of isobutane alkanes than the hydroisomerization feed stream, and the hydroisomerization feed stream will have a larger proportion of n-butane alkanes than the hydroisomerization stream. This principle generally applies to alkanes of all carbon numbers passing through the hydroisomerization reactor 130b, but is particularly applicable to alkanes with three to seventeen carbon atoms. The optimal amount of residual n-alkanes in line 134 depends on the selectivity of the hydroisomerization catalyst, but is typically between about 1% by weight and about 7% by weight.

[0070] In an exemplary embodiment, hydrocracking reactor 130a and hydroisomerization reactor 130b are stacked or located within a single vessel 130. In the stacked configuration of this disclosure, hydrocracking reactor 130a is positioned above hydroisomerization reactor 130b. For the stacked configuration, a combined hydrogenation feed stream, including a first recirculated diesel feed stream 182, is delivered to hydrocracking reactor 130a via line 132. The hydrocracking feed stream is extracted from the bottom of hydrocracking reactor 130a and delivered to hydroisomerization reactor 130b. A second recirculated diesel feed stream 184 is also delivered to hydroisomerization reactor 130b. The second recirculated diesel feed stream 184 bypasses hydrocracking reactor 130a. The hydroisomerization feed stream in hydroisomerization line 134 is extracted from the bottom of hydroisomerization reactor 130b.

[0071] The hydroisomerization feed stream from hydroisomerization reactor 130b in hydroisomerization line 134 flows to hydroisomerization stripping tower 140. In one aspect, the hydroisomerization feed stream in line 134 is separated in hydroisomerization stripping tower 140 to provide a hydroisomerization vapor feed stream in line 142 and a hydroisomerization liquid feed stream 144. A suitable stripping medium in line 143 is also passed to hydroisomerization stripping tower 140. An inert gas stripping medium, such as steam, from stripping medium line 143 can be used to strip light gases from the hydroisomerization feed stream in line 134. The hydroisomerization vapor feed stream containing light gases in line 142 is taken from the top of hydroisomerization stripping tower 140.

[0072] The hydroisomerization liquid stream 144 is taken from the bottom of the hydroisomerization stripping column 140 and transferred to the product distillation column 150 to produce a product stream without condensation and cooling.

[0073] The product distillation column 150 can be reboiled to provide the heat required for distillation by heat exchange with a suitable heat flow or in a flame heater. Alternatively, a stripping medium such as steam, as an inert gas, can be used to heat the column.

[0074] The product distillation column 150 provides a top gaseous stream of naphtha and vapor in the top line 152 and a bottom liquid stream in the bottom line 156. The top stream can be completely condensed and separated from water in the distillation receiver.

[0075] The product stream can be taken from one side of the product distillation column 150. The side stream containing the jet fuel stream in line 154 can also be taken from one side of the product distillation column 150. The jet fuel stream in line 154 may have a T5 of approximately 115°C (239℉) to approximately 130°C (266℉) and a T90 of approximately 240°C (464℉) to approximately 270°C (518℉). The jet fuel stream in line 154 will conform to ASTM D7566 jet fuel specifications.

[0076] Returning to the product distillation column 150, the bottom liquid feed in the bottom line 156 can be a diesel feed of T5 with a temperature of about 270°C (518°F) to about 320°C (608°F) and a temperature of about 330°C (626°F) to about 399°C (750°F). The product distillation column 150 can be operated at a bottom temperature between about 149°C (300°F) and about 288°C (550°F), preferably not exceeding about 260°C (500°F), and at a top pressure of about 0.35 MPa (gauge pressure) (50 psig), preferably not less than about 0.70 MPa (gauge pressure) (100 psig) and not exceeding about 2.0 MPa (gauge pressure) (290 psig).

[0077] The distillation column bottoms stream in distillation column bottoms line 156 has a relatively high concentration of n-alkanes. The distillation column bottoms stream can be further hydrogenated to further manage the n-alkanes concentration. The distillation column bottoms stream in line 156 can be recycled to the hydrogenation reactor 130.

[0078] The bottom liquid stream 156 of the distillation column can be separated into a product diesel stream in line 172 and a recirculated diesel stream in line 174. The recirculated diesel stream in line 174 is passed to the hydrogenation reactor 130. According to this disclosure, the recirculated diesel stream in line 174 is separated into a first recirculated diesel stream and a second recirculated diesel stream. In one aspect, the supplemental hydrogen recirculated stream in line 175 can be combined or mixed with the recirculated diesel stream in line 174, and then separated into a first recirculated diesel stream and a second recirculated diesel stream. The recirculated diesel stream in line 174 is mixed with the supplemental hydrogen recirculated stream in line 175 to provide a mixed diesel stream in line 176. The mixed diesel stream in line 176 is separated into a first recirculated diesel stream in line 177 and a second recirculated diesel stream in line 178.

[0079] According to this disclosure, the flow rates of the first recirculated diesel feed in line 177 and the second recirculated diesel feed in line 178 to the hydrocracking reactor 130a and the hydroisomerization reactor 130b are controlled and set to produce a jet fuel feed in line 154 that meets jet fuel specifications, preferably ASTM D7566 jet fuel specifications. In one aspect, a first proportion of the diesel feed to the first recirculated diesel feed in line 177 to the hydrocracking reactor 130a and a second proportion of the diesel feed to the second recirculated diesel feed in line 178 to the hydroisomerization reactor 130b are determined and controlled based on measurements of one or both of the density and viscosity of the jet fuel feed in line 154. According to this disclosure, the flow rates of the first recirculated diesel feed in line 177 and the second recirculated diesel feed in line 178 are set based on measurements of one or both of the density and viscosity of the jet fuel feed in line 154.

[0080] In an exemplary embodiment, the jet fuel flow in line 154 passes through measuring device 160. In this embodiment, measuring device 160 is a Coriolis mass flow meter. The Coriolis mass flow meter is connected to or communicates with an online densitometer 165. In this embodiment, the Coriolis mass flow meter is also connected to or communicates with an online viscometer 163. The online densitometer 165 compares a measured value of the density of the jet fuel flow in line 154 with a setpoint value for the desired density of the jet fuel. Similarly, the online viscometer 163 compares a measured value of the viscosity of the jet fuel flow in line 154 with a setpoint value for the desired viscosity of the jet fuel. Based on this comparison, the flow rates of the first recirculated diesel fuel flow in line 177 and the second recirculated diesel fuel flow in line 178 are determined and controlled as described below.

[0081] To regulate or control the flow rate, the first recirculated diesel feed in line 177 is passed via a first ratio controller 181 before its recirculation to the hydrocracking reactor 130a. Similarly, the second recirculated diesel feed in line 178 is passed to a second ratio controller 183 before its recirculation to the hydroisomerization reactor 130b. The first ratio controller 181 and the second ratio controller 183 are communicatively connected to an online densitometer 165 and an online viscometer 163. Based on the density or viscosity of the jet fuel feed, or a comparison of both, the first recirculated diesel feed in line 182, at a controlled flow rate via the first ratio controller 181, is passed to the hydrocracking reactor 130a, and the second recirculated diesel feed in line 184, at a controlled flow rate via the second ratio controller 183, is passed to the hydroisomerization reactor 130b.

[0082] If the measured density of the jet fuel stream in line 154 does not match the setpoint value of the desired jet fuel density, the desired flow rate of the first recirculated diesel stream in line 182 via the first ratio controller 181 is determined and adjusted so that the density of the jet fuel stream in line 154 matches the desired jet fuel density. Therefore, if the density of the jet fuel stream in line 154, as measured by densitometer 165, is higher than the setpoint value of the desired jet fuel density, the presence of heavier components in the jet fuel stream in line 154 is too high. Therefore, the flow rate of the first recirculated diesel stream in line 182 via the first ratio controller 181 can be increased so that a higher proportion of the recirculated diesel passes through the hydrocracking reactor 130a, thereby reducing the presence of heavier components in the jet fuel stream in line 154 through reduced hydrocracking. Proportionally, the flow rate of the second recirculated diesel stream in line 184, delivered to the hydroisomerization reactor 130b via the second ratio controller 183, is reduced.

[0083] On the other hand, if the density value of the jet fuel stream in pipeline 154, as measured by densitometer 165, is lower than the setpoint value of the desired density of the jet fuel, then the presence of lighter components in the jet fuel stream in pipeline 154 is excessive. Therefore, the flow rate of the first recirculated diesel stream in pipeline 182 via the first ratio controller 181 can be reduced, so that a lower proportion of the recirculated diesel is delivered to the hydrocracking reactor 130a, thereby reducing the presence of lighter components in the jet fuel stream in pipeline 154 through increased hydrocracking. Proportionally, the flow rate of the second recirculated diesel stream in pipeline 184, delivered to the hydroisomerization reactor 130b via the second ratio controller 183 while bypassing the hydrocracking reactor 130a, is increased.

[0084] Similarly, if the measured viscosity of the jet fuel stream in line 154 does not match the setpoint value of the desired viscosity of the jet fuel, the desired flow rate of the first recirculated diesel stream in line 182 via the first ratio controller 181 is determined and adjusted so that the viscosity of the jet fuel stream in line 154 matches the desired viscosity of the jet fuel. Therefore, if the viscosity of the jet fuel stream in line 154, as measured by the online viscometer 163, is higher than the setpoint value of the desired viscosity of the jet fuel, the presence of heavier components in the jet fuel stream in line 154 is too high. Therefore, the flow rate of the first recirculated diesel stream in line 182 via the first ratio controller 181 can be reduced so that a lower proportion of recirculated diesel is delivered to the hydrocracking reactor 130a, thereby reducing the presence of heavier components in the jet fuel stream in line 154 through reduced hydrocracking. Proportionally, the flow rate of the second recirculated diesel feed stream in pipeline 184, transmitted to the hydroisomerization reactor 130b via the second ratio controller 183, is increased.

[0085] However, if the viscosity of the jet fuel feed stream in line 154, as measured by the online viscometer 163, is lower than the setpoint value for the desired viscosity of the jet fuel, the presence of lighter components in the jet fuel feed stream in line 154 is excessive. Therefore, the flow rate of the first recirculated diesel feed stream in line 182 via the first ratio controller 181 can be increased, such that a higher proportion of the recirculated diesel is delivered to the hydrocracking reactor 130a, thereby reducing the presence of lighter components in the jet fuel feed stream in line 154 through increased hydrocracking. Proportionally, the flow rate of the second recirculated diesel feed stream in line 184, delivered to the hydroisomerization reactor 130b via the second ratio controller 183 while bypassing the hydrocracking reactor 130a, is reduced.

[0086] In an exemplary embodiment, the first recirculated diesel fuel stream in pipeline 182 may account for about 10% to about 90% by weight of the diesel fuel stream in pipeline 176. In another exemplary embodiment, the second recirculated diesel fuel stream in pipeline 184 may account for about 90% to about 10% by weight of the diesel fuel stream in pipeline 176.

[0087] The system space velocity is typically expressed in hours as the standard volumetric flow rate of the feed divided by the volume of the catalyst bed. Liquid hourly space velocity (LHSV) is typically defined as the standard volumetric flow rate of the liquid feed divided by the volume of the catalyst bed and expressed in hours. In one aspect, the volume of the hydrocracking catalyst in hydrocracking catalyst reactor 130a or hydrocracking catalyst bed 135a is less than or equal to the volume of the hydroisomerization catalyst in hydroisomerization reactor 130b or hydroisomerization catalyst bed 135b. According to an exemplary embodiment, the LHSV of hydrocracking reactor 130a is greater than or equal to the LHSV of hydroisomerization reactor 130b, regardless of the flow rate of the recirculated diesel feed in lines 182 and 184. According to this disclosure, the LHSV may be based on the flow rate of the hydrotreated liquid feed in line 126. The hydrotreated liquid feed in line 126 is passed together with the first recirculated diesel feed in line 182 to hydrocracking reactor 130a. On the one hand, the LHSV in each reactor can be controlled by controlling the flow rate of recirculated diesel into each of the hydrocracking reactor 130a and the hydroisomerization reactor 130b.

[0088] A dual-injection configuration with a variable LHSV for recirculated diesel feedstock produces jet fuel range material that meets ASTM D7566 jet fuel specifications, while also maintaining or increasing the yield of the produced jet fuel range material. For example... Figure 1 As shown, jet fuel feed streams that meet ASTM D7566 jet fuel specifications can be drawn from distillation column 150 in line 154 from line 162.

[0089] Any of the aforementioned pipelines, conduits, units, equipment, containers, surrounding environment, areas, or the like may be equipped with one or more monitoring components, including sensors, measuring devices, data acquisition devices, or data transmission devices. Signal, method, or condition measurements, as well as data from the monitoring components, can be used to monitor conditions within, around, and in connection with the method or equipment. Signals, measurements, and / or data generated or recorded by the monitoring components may be collected, processed, and / or transmitted through one or more networks or connections, which may be private or public, general or dedicated, direct or indirect, wired or wireless, encrypted or unencrypted, and / or combinations thereof; this specification is not intended to be limiting in this respect.

[0090] Signals, measurements, and / or data generated or recorded by monitoring components may be transmitted to one or more computing devices or systems. The computing devices or systems may include at least one processor and a memory storing computer-readable instructions that, when executed by the at least one processor, cause the one or more computing devices to perform a method that may include one or more steps. For example, one or more computing devices may be configured to receive data from one or more monitoring components related to at least one piece of equipment associated with the process. One or more computing devices or systems may be configured to analyze the data. Based on the data analysis, one or more computing devices or systems may be configured to determine one or more recommended adjustments to one or more parameters of one or more methods described herein. One or more computing devices or systems may be configured to transmit encrypted or unencrypted data that includes one or more recommended adjustments to one or more parameters of one or more methods described herein.

[0091] Example

[0092] Simulation studies were conducted using three different feedstocks: normal feedstock, heavy feedstock, and light feedstock. These three different feedstocks were used in the simulation studies to demonstrate the benefits of splitting the recirculated diesel feedstock into a first recirculated diesel feedstock and a second recirculated diesel feedstock at the desired split ratio.

[0093] Example 1

[0094] In Example 1, the yield of jet fuel or sustainable aviation fuel (SAF) was compared to the percentage of the first recycle diesel feedstock recycled to the hydrocracking catalyst for normal, heavy, and light feedstocks. Simulations were conducted at constant reactor temperature, pressure, and SAF fractionation point for all three feedstocks. The percentage of the first recycle diesel feedstock represents the portion of the recycle diesel feedstock recycled to the hydrocracking catalyst. The SAF yield versus the percentage of the first recycle diesel feedstock is plotted and shown in [Figure / Table / Insert Table ... Figure 2 From the middle. For example, from Figure 2 As confirmed in the study, for all three feed types (normal feed, heavy feed, and light feed), SAF yield increases with the percentage of the first recycle diesel feed stream recycled to the hydrocracking catalyst.

[0095] Example 2

[0096] In Example 2, for three feedstocks, the SAF pour point was compared to the percentage of the first recycle diesel feedstock recycled to the hydrocracking catalyst. Simulations were conducted for all three feedstocks at constant reactor temperature, pressure, and SAF fractionation point. The percentage of the SAF pour point to the first recycle diesel feedstock recycled to the hydrocracking catalyst was plotted and shown below. Figure 3 From the middle. For example, from Figure 3 As confirmed in the study, it was found that for all three feed types (normal feed, heavy feed, and light feed), the SAF pour point was improved by increasing the percentage of the first recycle diesel feed stream recycled to the hydrocracking catalyst.

[0097] Example 3

[0098] In Example 3, for three feedstocks, the SAF density was compared with the percentage of the first recycle diesel feedstock recycled to the hydrocracking catalyst. To this end, a graph was plotted for the three feedstocks showing the combined feed ratio (CFR) versus the percentage of the first recycle diesel feedstock recycled to the hydrocracking catalyst. The combined feed ratio was calculated as the volume ratio of (feed rate + recycle rate) / feed rate. Simulation studies were conducted for all three feedstocks at constant reactor temperature, pressure, and SAF fractionation point. The percentage of CFR versus the first recycle diesel feedstock recycled to the hydrocracking catalyst is plotted and shown below. Figure 4 According to the findings, for all three feed types (normal feed, heavy feed, and light feed), SAF density was improved by increasing the percentage of the first recycle diesel feed stream recycled to the hydrocracking catalyst.

[0099] Specific implementation plan

[0100] While the following description is presented in conjunction with specific embodiments, it should be understood that the description is intended to be illustrative and not to limit the scope of the foregoing description and the appended claims.

[0101] A first embodiment of this disclosure is a method for hydrogenating a biorenewable feedstock, the method comprising: hydrogenating a biorenewable feedstock stream in the presence of hydrogen via a hydrogenation catalyst in a hydrogenation reactor to hydrodeoxygenate the biorenewable feedstock stream, thereby providing a hydrogenation feedstock; hydrocracking a hydrocracking feedstock stream taken from the hydrogenation feedstock stream in the presence of hydrogen via a hydrocracking catalyst in a hydrocracking reactor, thereby providing a hydrocracking feedstock stream; hydroisomerizing a hydroisomerizing feedstock stream taken from the hydrogenation feedstock stream in the presence of hydrogen via a hydroisomerizing catalyst in a hydroisomerizing reactor, thereby providing a hydroisomerizing feedstock stream; separating a jet fuel stream and a diesel stream from the hydroisomerizing feedstock stream; separating the diesel stream into a first recycle diesel stream and a second recycle diesel stream; passing the first recycle diesel stream to the hydrogenation cracking reactor; and passing the second recycle diesel stream to the hydroisomerizing reactor. Embodiments of this disclosure are any one or all of the embodiments described in the preceding embodiments to the first embodiment described in this paragraph, wherein the second recycled diesel feed stream bypasses the hydrocracking reactor. Embodiments of this disclosure are any one or all of the embodiments described in the preceding embodiments to the first embodiment described in this paragraph, wherein the hydrocracking reactor and the hydroisomerization reactor are located in a single vessel. Embodiments of this disclosure are any one or all of the embodiments described in the preceding embodiments to the first embodiment described in this paragraph, further comprising passing the first recycled diesel feed stream to the hydrocracking reactor to provide the hydrocracking feed stream; and passing the hydrocracking feed stream and the second recycled diesel feed stream to the hydroisomerization reactor to provide the hydroisomerization feed stream. Embodiments of this disclosure include any one or all of the previous embodiments to the first embodiment in this paragraph, further comprising measuring one or both of the density and viscosity of the jet fuel stream; and setting the flow rates of the first recirculated diesel stream and the second recirculated diesel stream based on the measured values ​​of one or both of the density and viscosity of the jet fuel stream. Embodiments of this disclosure include any one or all of the previous embodiments to the first embodiment in this paragraph, wherein the hydrocracking reactor is located above the hydroisomerization reactor in the vessel. Embodiments of this disclosure include any one or all of the previous embodiments to the first embodiment in this paragraph, further comprising mixing the diesel stream with a supplemental hydrogen stream to provide a mixed diesel stream; and separating the mixed diesel stream to provide the first recirculated diesel stream and the second recirculated diesel stream.Embodiments of this disclosure are any one or all of the embodiments described in the preceding embodiments to the first embodiment described in this paragraph, and further include transferring the hydrogen feed stream to the container at a location between the hydrocracking reactor and the hydroisomerization reactor. Embodiments of this disclosure are any one or all of the embodiments described in the preceding embodiments to the first embodiment described in this paragraph, and further include controlling the recirculation of the diesel feed stream to the hydrocracking reactor and the hydroisomerization reactor by measuring one or both of the density and viscosity of the jet fuel feed stream; comparing the measured values ​​of one or both of the density and viscosity of the jet fuel feed stream with a setpoint value of one or both of the density and viscosity of the jet fuel feed stream to determine a first proportion of the diesel feed stream fed into the first recirculated diesel feed stream and a second proportion of the diesel feed stream fed into the second recirculated diesel feed stream; transferring the first recirculated diesel feed stream to a hydrocracking catalyst bed located in the hydrocracking reactor; and transferring the second recirculated diesel feed stream to a hydroisomerization catalyst bed located in the hydroisomerization reactor. The embodiments of this disclosure are one, any, or all of the embodiments described in the preceding embodiments to the first embodiment described in this paragraph, wherein the first recirculated diesel feed stream comprises about 10% to about 90% by weight of the diesel feed stream, and the second recirculated diesel feed stream comprises about 90% to about 10% by weight of the diesel feed stream. The embodiments of this disclosure are one, any, or all of the embodiments described in the preceding embodiments to the first embodiment described in this paragraph, wherein the hydrocracking reactor operates at a first liquid hour space velocity (LIWV), and the hydroisomerization reactor operates at a second LIWV, wherein the first LIWV is higher than or equal to the second LIWV.

[0102] A second embodiment of this disclosure is a method for hydrogenating a biorenewable feedstock, the method comprising: hydrogenating the biorenewable feedstock stream in the presence of hydrogen via a hydrogenation catalyst in a hydrogenation reactor to hydrodeoxygenate the biorenewable feedstock stream, thereby providing a hydrogenation feedstock; hydrocracking a hydrocracking feedstock stream taken from the hydrogenation feedstock stream in the presence of hydrogen via a hydrocracking catalyst in a hydrocracking reactor, thereby providing a hydrocracking feedstock stream; and hydroisomerizing a hydroisomerized feedstock stream taken from the hydrogenation feedstock stream in the presence of hydrogen via a hydroisomerization catalyst in a hydroisomerization reactor. A feed stream is provided to supply a hydroisomerization stream; a jet fuel stream and a diesel stream are separated from the hydroisomerization stream; one or both of the density and viscosity of the jet fuel stream are measured; the diesel stream is separated into a first recycle diesel stream and a second recycle diesel stream; the flow rates of the first recycle diesel stream and the second recycle diesel stream are set based on the measured values ​​of one or both of the density and viscosity of the jet fuel stream; the first recycle diesel stream is fed to the hydrocracking reactor; and the second recycle diesel stream is fed to the hydroisomerization reactor. Embodiments of this disclosure are any one or all of the embodiments described in the preceding to the second embodiments of this paragraph, wherein the first recycle diesel stream comprises about 10% to about 90% by weight of the diesel stream, and the second recycle diesel stream comprises about 90% to about 10% by weight of the diesel stream. Embodiments of this disclosure are any one or all of the embodiments described in the preceding to the second embodiments of this paragraph, wherein the hydrocracking reactor and the hydroisomerization reactor are located in a single vessel. Embodiments of this disclosure are any one or all of the embodiments described in the preceding to the second embodiments of this paragraph, wherein the hydrocracking reactor is positioned above the hydroisomerization reactor within the vessel. Embodiments of this disclosure are any one or all of the embodiments described in the preceding to the second embodiments of this paragraph, wherein the second recycled diesel feed stream bypasses the hydrocracking reactor. Embodiments of this disclosure are any one or all of the embodiments described in the preceding to the second embodiments of this paragraph, further comprising passing the first recycled diesel feed stream to the hydrocracking reactor to provide the hydrocracking feed stream; and passing the hydrocracking feed stream and the second recycled diesel feed stream to the hydroisomerization reactor to provide the hydroisomerization feed stream.Embodiments of this disclosure are any one or all of the embodiments described in the preceding to the second embodiments of this paragraph, wherein the hydrocracking reactor operates at a first liquid hourly space velocity (LISH), and the hydroisomerization reactor operates at a second LISH, wherein the first LISH is higher than or equal to the second LISH. Embodiments of this disclosure are any one or all of the embodiments described in the preceding to the second embodiments of this paragraph, further comprising mixing the diesel feed stream with a supplemental hydrogen feed stream to provide a mixed diesel feed stream; and separating the mixed diesel feed stream to provide a first recirculated diesel feed stream and a second recirculated diesel feed stream. Embodiments of this disclosure are any one or all of the embodiments described in the preceding to the second embodiments of this paragraph, wherein the step of setting the flow rate includes comparing a measurement of one or both of the density and viscosity of the jet fuel feed stream with a setpoint value of one or both of the density and viscosity of the diesel feed stream to determine a first proportion of the diesel feed stream fed into the first recirculated diesel feed stream and a second proportion of the diesel feed stream fed into the second recirculated diesel feed stream.

[0103] Although no further detailed description has been provided, it is believed that those skilled in the art can make full use of this disclosure by employing the foregoing description and can readily identify the essential features of this disclosure without departing from the spirit and scope of the invention, and can make various changes and modifications to adapt it to various uses and situations. Therefore, the foregoing preferred specific embodiments should be understood as illustrative only and not as limiting the remainder of this disclosure in any way, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0104] In the foregoing, all temperatures are expressed in degrees Celsius, and all portions and percentages are by weight unless otherwise specified.

Claims

1. A method for hydrogenating biorenewable feedstocks, the method comprising: In a hydrotreating reactor, the biorenewable feed stream is hydrotreated by a hydrotreating catalyst in the presence of hydrogen to hydrodeoxygenate the biorenewable feed stream in order to provide a hydrotreated feed stream; In a hydrocracking reactor, the hydrocracking feed stream taken from the hydrotreated feed stream is hydrocracking in the presence of hydrogen via a hydrocracking catalyst to provide the hydrocracking feed stream; In a hydroisomerization reactor, a hydroisomerization feed stream taken from the hydrotreatment feed stream is hydroisomerized by a hydroisomerization catalyst in the presence of hydrogen to provide a hydroisomerization feed stream; Separate the jet fuel stream and the diesel stream from the hydroisomerized feed stream; The diesel fuel stream is separated into a first recirculated diesel fuel stream and a second recirculated diesel fuel stream; The first recycled diesel feed stream is passed to the hydrocracking reactor; as well as The second recycled diesel feed stream is passed to the hydroisomerization reactor.

2. The method of claim 1, wherein the second recirculated diesel feed bypasses the hydrocracking reactor.

3. The method according to claim 1, wherein the hydrocracking reactor and the hydroisomerization reactor are located in a single vessel.

4. The method according to claim 3, further comprising: The first recycled diesel feed stream is passed to the hydrocracking reactor to provide the hydrocracking feed stream; as well as The hydrocracking feedstock and the second recycled diesel are fed to the hydroisomerization reactor to provide the hydroisomerization feedstock.

5. The method according to claim 1, further comprising: Measure one or both of the density and viscosity of the jet fuel stream; and The flow rates of the first recirculated diesel stream and the second recirculated diesel stream are set based on measurements of one or both of the density and viscosity of the jet fuel stream.

6. The method of claim 3, wherein the hydrocracking reactor is located above the hydroisomerization reactor in the vessel.

7. The method according to claim 1, further comprising: The diesel fuel stream is mixed with a supplemental hydrogen fuel stream to provide a mixed diesel fuel stream; as well as The mixed diesel stream is separated to provide a first recirculated diesel stream and a second recirculated diesel stream.

8. The method of claim 3, further comprising delivering a hydrogen feed stream to the container at a location between the hydrocracking reactor and the hydroisomerization reactor.

9. The method of claim 5, further comprising controlling the recirculation of the diesel feedstock to the hydrocracking reactor and the hydroisomerization reactor by means of: Measure one or both of the density and viscosity of the jet fuel stream; The measured value of one or both of the density and viscosity of the jet fuel stream is compared with the setpoint value of one or both of the density and viscosity of the jet fuel stream to determine a first proportion of the diesel stream fed into the first recirculated diesel stream and a second proportion of the diesel stream fed into the second recirculated diesel stream. The first recycled diesel feed stream is passed to the hydrocracking catalyst bed located in the hydrocracking reactor; as well as The second recycled diesel feed stream is passed to the hydroisomerization catalyst bed located in the hydroisomerization reactor.

10. The method of claim 1, wherein the first recirculated diesel stream comprises about 10% to about 90% by weight of the diesel stream, and the second recirculated diesel stream comprises about 90% to about 10% by weight of the diesel stream.

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