阅读说明：本技术 0℃下无浑浊重质基础油和用于生产的方法 (Haze-free heavy base oil at 0 ℃ and method for production ) 是由 N·布芒杰尔 R·G·迈斯特 C·H·M·范德许尔斯特 N·范戴克 于 2019-08-28 设计创作，主要内容包括：一种用于由脱沥青油(DAO)进料生产基础油组合物的方法,其中所述DAO进料进行加氢处理、加氢裂化、催化脱蜡、加氢精制和分馏以生成所述基础油组合物。所述基础油组合物包含0℃下无浑浊重质基础油,所述0℃下无浑浊重质基础油包括：(a)在100℃下范围为15cSt到21cSt的动力粘度；(b)至少95的5粘度指数；(c)低于-12℃的倾点；(d)低于-18℃的浊点；以及(e)2wt％或更少的总芳香族化合物含量,其中在测试时间段期间,所述0℃下无浑浊重质基础油在不受干扰地储存在0℃下时维持无浑浊外观。(A process for producing a base oil composition from a deasphalted oil (DAO) feed, wherein the DAO feed is hydrotreated, hydrocracked, catalytically dewaxed, hydrofinished, and fractionated to produce the base oil composition. The base oil composition comprises a haze free heavy base oil at 0 ℃, the haze free heavy base oil at 0 ℃ comprising: (a) a kinematic viscosity at 100 ℃ in the range of 15cSt to 21 cSt; (b) a 5 viscosity index of at least 95; (c) a pour point of less than-12 ℃; (d) a cloud point of less than-18 ℃; and (e) a total aromatics content of 2 wt% or less, wherein the haze-free heavy base oil at 0 ℃ maintains a haze-free appearance when stored undisturbed at 0 ℃ during the test period.)

1. A method for producing a base oil composition, the method comprising:

(a) providing a deasphalted oil (DAO) feed;

(b) hydrotreating a portion of the DAO feed in the presence of a hydrotreating catalyst to produce a hydrotreated product;

(c) hydrocracking the hydrotreated product in the presence of a hydrocracking catalyst to produce a hydrocracked product;

(d) fractionating the hydrocracked product, wherein at least one fraction comprises hydrogen wax (hydrowax);

(e) catalytically dewaxing the hydrogen wax in the presence of a noble metal-based catalyst to produce a dewaxed product;

(f) hydrofinishing the dewaxed product in the presence of a hydrofinishing catalyst to produce a hydrofinished product;

(g) fractionating the hydrofinished product, wherein at least one fraction comprises the base oil composition; and is

Wherein the base oil composition is a haze free heavy base oil at 0 ℃, the haze free heavy base oil at 0 ℃ comprising: (a) a kinematic viscosity at 100 ℃ in the range of 15cSt to 21 cSt; (b) a viscosity index of at least 95; (c) a pour point of less than-12 ℃; (d) a cloud point of less than-18 ℃; and (e) a total aromatics content of 2 wt% or less;

wherein during a test period the haze-free heavy base oil at 0 ℃ maintains a haze-free appearance when stored undisturbed at 0 ℃; and is

Wherein the haze free heavy base oil composition at 0 ℃ is a group II/III base oil.

2. The method of claim 1, wherein the base oil composition is a haze free heavy base oil at 0 ℃, the haze free heavy base oil at 0 ℃ comprising: (a) a kinematic viscosity at 100 ℃ in the range of 19cSt to 20 cSt; (b) a viscosity index ranging from 100 to 119 for the group II base oil and at least 120 for the group III base oil; (c) a pour point of less than-24 ℃; (d) a cloud point of less than-21 ℃; and (e) a total aromatics content of 1 wt% or less; and is

Wherein the haze-free heavy base oil at 0 ℃ maintains a haze-free appearance when stored undisturbed at 0 ℃ during the test period.

3. The method of any of claims 1-2, wherein the base oil composition comprises a sulfur content of less than 5ppm and a nitrogen content of less than 5 ppm.

4. The method of any of claims 1-2, wherein the base oil composition comprises a sulfur content of less than 1ppm and a nitrogen content of less than 1 ppm.

5. The method of any one of claims 1-2, wherein the base oil composition comprises a saturates content ranging from about 98 wt% to about 99.9 wt%.

6. The method of any one of claims 1-2, wherein the test period of time is at least 5 hours.

7. The method of any one of claims 1-2, wherein the test period of time is at least 7 hours.

8. The process of claim 1, wherein the DAO feed comprises at least 50 wt.% hydrocarbons boiling above 450 ℃, at least 400ppm nitrogen, at least 0.5 wt.% sulfur, and a metal content of (nickel (Ni) + vanadium (V)) in the range of 2-250 ppm.

9. The process of claim 1, wherein the DAO feed comprises more than 65 wt% hydrocarbons boiling above 450 ℃.

10. The process of any one of claims 8 to 9 wherein the DAO feed comprises at least one of neat DAO or a blend of DAO and Vacuum Gas Oil (VGO), and wherein the blend of DAO and VGO comprises a ratio of about 6:1 to about 1: 6.

11. The process of any one of claims 8 to 9 wherein the DAO feed comprises a blend of DAO, VGO, and a portion of the hydrogen wax, in any combination thereof.

12. The process of any one of claims 1 to 11, wherein the hydrotreated product comprises nitrogen in the range of 0.1-30ppm, sulfur in the range of 10-200ppm, and a total absorption of at least 30% of the (Ni + V) metal content.

13. The process of any one of claims 1 to 12, wherein the hydrocracking catalyst at step (c) comprises a zeolite component.

14. The process of any one of claims 1 to 13, wherein the hydrocracking catalyst at step (c) comprises an additional zeolite component selected from zeolite beta, zeolite ZSM-5 or zeolite Y.

15. The process of any one of claims 1 to 14, further comprising a hydrotreating catalyst bed at step (c) for producing the hydrocracked product.

16. The process as claimed in any one of claims 1 to 15, wherein the hydrocracking conditions of step (c) include a temperature in the range of 250-^-1Weight hourly space velocity of.

17. The process of any one of claims 1-16, wherein the hydrogen wax at step (d) comprises a kinematic viscosity at 100 ℃ of at least 4.0cSt, a viscosity index of at least 120, a nitrogen content below 20ppm, and a sulfur content below 100 ppm.

18. The process of any one of claims 1 to 17, further comprising stripping residual products from the hydrocracked products at step (d), wherein the residual products comprise ammonia (NH)₃) Hydrogen sulfide (H)₂S), methane (CH)₄) Ethane (C)₂H₆) At least one of Liquefied Petroleum Gas (LPG), naphtha and gas oil.

19. The process of any one of claims 1-18, wherein the noble metal-based catalyst of step (e) comprises a fractionated mixture comprising ZSM-12 and modified ZSM-12 zeolite-based catalysts and EU-2 and/or ZSM-48 zeolite-based catalysts.

20. The process of any one of claims 1 to 19, wherein the noble metal-based catalyst of step (e) comprises the fractionated mixture and a noble metal aromatic hydrogenation catalyst.

21. The process as claimed in any one of claims 1 to 20, wherein the catalytic dewaxing conditions of step (e) comprise a temperature in the range of 200-Bed Temperature (WABT), gas-oil ratio in the range of 500-1500NI/kg and in the range of 0.2-10 hours^-1Weight hourly space velocity (WHSC).

22. The process as claimed in any one of claims 1 to 21, wherein the hydrofinishing conditions at step (f) include a temperature in the range of 125-390 ℃, a pressure in the range of 70-200 bar, a Weighted Average Bed Temperature (WABT) in the range of 220-270 ℃, a gas-oil ratio in the range of 500-1500NI/kg and a time in the range of 0.3-3.0 hours^-1Weight hourly space velocity (WHSC).

23. The process of any one of claims 1 to 22, wherein at least one of the hydrofinishing catalysts of step (f) is a noble metal aromatic hydrogenation catalyst.

24. A base oil composition, comprising:

(a) a kinematic viscosity at 100 ℃ in the range of 15cSt to 21 cSt;

(b) a viscosity index of at least 95;

(c) a pour point of less than-12 ℃;

(d) a cloud point of less than-18 ℃;

(e) a total aromatic content of 2 wt% or less; and is

Wherein the base oil composition is a haze-free heavy base oil at 0 ℃ that maintains a haze-free appearance when stored undisturbed at 0 ℃ during a test period; and is

Wherein the haze free heavy base oil composition at 0 ℃ is a group II/III base oil.

25. The base oil composition of claim 24, further comprising:

(a) a kinematic viscosity at 100 ℃ in the range of 19cSt to 20 cSt;

(b) a viscosity index ranging from 100 to 119 for the group II base oil and at least 120 for the group III base oil;

(c) a pour point of less than-24 ℃;

(d) a cloud point of less than-21 ℃;

(e) a total aromatic content of 1 wt% or less.

Wherein the base oil composition is a haze-free heavy base oil at 0 ℃ that maintains a haze-free appearance when stored undisturbed at 0 ℃ during the test period.

26. The base oil composition of any one of claims 24 to 25, wherein the test period of time is at least 5 hours.

27. The base oil composition of any one of claims 24 to 25, wherein the test period of time is at least 7 hours.

28. The base oil composition of any one of claims 24 to 27 further comprising a sulfur content of less than 5ppm and a nitrogen content of less than 5 ppm.

29. The base oil composition of any one of claims 24 to 27 further comprising a sulfur content of less than 1ppm and a nitrogen content of less than 1 ppm.

30. The base oil composition of any one of claims 24 to 29, further comprising a saturates content ranging from about 98 wt% to about 99.9 wt%.

31. The base oil composition according to any one of claims 24 to 30, wherein the total aromatics content comprises a mono-aromatic content and a polycyclic aromatic content.

Technical Field

The present invention relates to a haze-free heavy base oil at 0 ℃ and a process for producing a heavy base oil from a deasphalted oil feed.

Background

Heavy lubricating base oils used in formulations of engine oils and industrial oils may be prepared from suitable hydrocarbon feeds derived from deasphalting of atmospheric or vacuum residues. One example of a hydrocarbon feed for producing heavy base oils comprises deasphalted oil (DAO). DAO is typically subjected to several processing steps, such as hydrotreating to remove nitrogen, sulfur, metals, and other contaminants, and hydrocracking to reduce the molecular weight of aromatics and haze precursors. Hydrotreating and hydrocracking can also increase the viscosity index and kinematic viscosity of the resulting base oil product.

While considered a suitable feed due to its high viscosity, DAO is indeed rich in wax compounds that are solid at ambient temperature and often imparts undesirably high pour and cloud points to the base oil product. Such undesirable properties, as well as others, may hinder the production work, use, storage and transportation of such base oils. Thus, additional steps of catalytic dewaxing and hydrofinishing comprising DAO can improve cold flow properties and overall product stability by removing wax compounds, which lowers the pour and cloud points of the base oil produced thereafter.

However, even after catalytic dewaxing of DAO feeds, the base oil product may still contain naturally occurring haze precursors, e.g., paraffin-like wax compounds and other wax compounds. If present in sufficient amounts, the haze precursors form a visual haze in the base oil at ambient temperature, particularly if the base oil is allowed to stand at low temperatures for an extended period of time. Visual haze appears as a milky or cloudy appearance, which leads to reduced visual quality and undesirable properties of the base oil product at low temperature conditions. Haze precursors may also affect filterability of base oils or finished lubricants containing base oils.

Thus, the DAO feed may be hydrotreated to initially remove contaminants such as nitrogen, and then subjected to additional dewaxing and distillation steps to remove wax compounds. However, additional and/or more severe process steps may reduce the product yield and thus significantly reduce the ratio of heavy to light base oil. During periods of high demand for heavy base oils, it is generally undesirable to reduce the yield of such oils.

Thus, there is a continuing need for base oil compositions having improved low cold flow properties and which are continuously used during low temperature applications and methods for their production that provide maximum production yields.

Disclosure of Invention

The present invention provides a haze-free heavy base oil at 0 ℃ and a method for producing the same. The process comprises providing a deasphalted oil (DAO) feed containing at least 50 wt.% hydrocarbons boiling above 450 ℃, nitrogen present in an amount ranging from 400-2500ppm or more, sulfur present in an amount ranging from 0.5 to 4.0 wt.% or more, and a (nickel (Ni) + vanadium (V)) metal content present in an amount ranging from 2 to 250 ppmw. Hydrotreating a portion of the DAO feed in the presence of a hydrotreating catalyst to produce a hydrotreated product containing nitrogen present in an amount in the range of from 0.1 to 30ppmw, sulfur present in an amount in the range of from 10 to 200ppmw, and a total absorption that is at least 30% of the (Ni + V) metal content. The hydrotreated product is hydrocracked in the presence of a hydrocracking catalyst to produce hydrocracked products that are fractionated into light distillates, middle distillates and hydrogen waxes. The hydrogen wax is catalytically dewaxed in the presence of a noble metal-based catalyst to produce a dewaxed product. The dewaxed product is hydrofinished in the presence of a hydrofinishing catalyst to produce a hydrofinished product. The hydrofinished product is fractionated to produce at least one fraction comprising a haze-free heavy base oil at 0 ℃ which can maintain a haze-free appearance when stored undisturbed at 0 ℃ during a test period of at least 5 hours (preferably at least 7 hours). Wherein the fractionated haze-free heavy base oil at 0 ℃ that is recovered is a group II/III base oil that maintains a haze-free appearance when stored undisturbed at 0 ℃ during the testing period.

The haze-free heavy base oil at 0 ℃ of the invention comprises: a kinematic viscosity at 100 ℃ in the range of 15cSt to 21 cSt; a viscosity index ranging from 95 to above 120; a pour point of less than-12 ℃; a cloud point of less than-18 ℃; and a total aromatic content of 2 wt% or less.

Drawings

Certain exemplary embodiments are described in the following detailed description and with reference to the accompanying drawings, in which:

the figure shows an exemplary embodiment of a process for the production of haze-free heavy base oil at 0 ℃ from Deasphalted (DAO) feed.

Detailed Description

The present invention discloses a haze-free heavy base oil composition at 0 ℃ and a process for producing the same. The process comprises hydrotreating, hydrocracking, catalytic dewaxing and hydrofinishing a DAO feed in the presence of a noble metal and a metal based catalyst to produce a haze free heavy base oil at 0 ℃. The haze-free heavy base oil at 0 ℃ comprises: a kinematic viscosity at 100 ℃ in the range of from 15 to 21cSt, preferably at 100 ℃ in the range of from 19 to 20cSt, and a viscosity index in the range of from 95 to 119 when prepared as a group II base oil, and a viscosity index above 120 when prepared as a group III base oil. In addition, a haze free heavy base oil at 0 ℃ comprises a pour point below-12 ℃, preferably below-18 ℃, and more preferably below-24 ℃, a cloud point below-18 ℃, preferably below-21 ℃, and a total aromatics content of less than 2 wt%, preferably less than 1 wt%.

The haze free heavy base oil composition at 0 ℃ of the present invention comprises a group II/III lubricating base oil having improved cold flow properties, including reduced cloud point and pour point. Furthermore, the present composition maintains a haze-free appearance upon storage and/or transport at 0 ℃ without stirring (i.e. in an undisturbed state) for an extended period of time, e.g. 5 hours, preferably 7 hours. Thus, the compositions of the present invention are desirable for use, storage and transportation activities during heavy cryogenic applications. In addition to improved cold flow properties, the haze-free heavy base oils at 0 ℃ of the present invention provide final product stability properties, including reduced contaminants (e.g., nitrogen, sulfur, aromatics), no haze formation during low temperature applications, and higher viscosity index and kinematic viscosity. The process of the present invention comprising the use of a metal-based catalyst and a noble metal-based catalyst surprisingly produces a higher yield of haze-free heavy base oil at 0 ℃ than conventional base oil production processes.

DAO feedstock

The DAO feed is obtained by deasphalting a residual hydrocarbon oil, preferably an atmospheric or vacuum residue fraction. Deasphalting processes are well known in the art and are performed in any conventional manner known to those skilled in the art. The DAO feed has a boiling point in the range of about 300 ℃ to about 1000 ℃ and contains at least 50 wt.% hydrocarbons boiling above 450 ℃. Preferably, the DAO feed contains more than 65 wt% but at least 50 wt% hydrocarbons boiling above 450 ℃.

The DAO feed used during this example was either pure DAO or a blend of DAO and Vacuum Gas Oil (VGO) in a ratio of about 6:1 to about 1: 6. In other embodiments of the invention, the DAO feed is a blend of two or more combinations thereof of DAO, VGO, or hydrogen wax. The hydrogen wax is a paraffin fraction having a boiling point range of typically 280 ℃ to 900 ℃ and is obtained in this example after subjecting the hydrocracked product to distillation, as explained later herein.

The DAO feed includes nitrogen, sulfur, and aromatics, and a metal content (nickel (Ni) + vanadium (V)) ranging from about 2 to about 250ppm or higher. The nitrogen content is at least 400ppm or greater based on the total weight of the DAO feed residue. The sulfur content was 0.5 weight percent (wt%) or greater based on the total weight of the DAO feed residue. The aromatic content of the DAO feed ranges from at least 20 wt% to 90 wt%, more specifically at least 30 wt% to 70 wt%, and may contain mono-aromatic, di-aromatic and/or polycyclic aromatic content.

The DAO feed also includes a wax content of up to 40 wt%. Thus, the use of DAO as a feed typically produces base oils with unacceptable levels and tendencies of haze precursors and haze formation. Thus, the DAO feed described herein is subjected to hydrotreating, hydrocracking, catalytic dewaxing and hydrofinishing steps, as well as other processing steps, in the presence of a metal-based catalyst and a noble metal-based catalyst to produce the haze-free heavy base oil of the present invention at 0 ℃.

Hydroprocessing

At step (a), the DAO feed is provided, for example, from a storage tank, separator, or any known type of containment vessel. During hydrotreating at step (b), contacting a portion of the DAO feed with hydrogen in the presence of a hydrotreating catalyst system within the reactor to produce a hydrotreated product. Preferably, the hydrotreated product is a heavy feed having an initial boiling point above about 300 ℃ and a final boiling point of less than about 700 ℃. Also preferably, at least 90 wt% of the hydrotreated product has a boiling temperature above 570 ℃ and at least 95 wt% of the hydrotreated product has a boiling temperature above 595 ℃. After completion of the hydrotreating step (b), the hydrotreated product comprises a reduced nitrogen content in the range of from about 0.1 to about 30ppm and a reduced sulfur content in the range of from 10 to 200 ppm.

The hydroprocessing catalyst system comprises a combination of suitable catalysts for reducing and/or removing metals, nitrogen, sulfur, and aromatics, as well as other contaminants, from the DAO feed. The hydroprocessing catalyst system can be configured in any suitable configuration within the reactor. In a preferred embodiment, the hydroprocessing catalyst system comprises at least one hydrodemetallization catalyst and at least one hydroprocessing catalyst. More preferably, prior to exposing the DAO feed to the hydrotreating catalyst, the DAO feed is initially exposed to at least one hydrodemetallization catalyst for metal absorption of nickel (Ni) and vanadium (V). Prior exposure to the hydrodemetallization catalyst can reduce or minimize deactivation of the hydrotreating catalyst and/or other subsequent catalysts used during the remaining process steps.

The total absorption of at least 30 wt% of the Ni-V metal concentration in the DAO feed is provided using a commercially available bimodal hydrodemetallization catalyst comprising a metal hydrogenation component, suitably a group IVB or group VIII metal (e.g. nickel-molybdenum, cobalt-molybdenum), on a porous support (e.g. silica-alumina or alumina). After metal absorption, the DAO feed is exposed to at least one suitable hydrotreating catalyst.

Preferably, the hydrotreating catalyst may comprise a support material loaded with a catalytically active metal compound, an amine compound, and a non-amine containing polar additive, as described in U.S. patent No. 9,516,029 and U.S. patent No. 9,586,499, which are incorporated herein by reference. The support material for the hydroprocessing catalyst includes any suitable inorganic oxide material typically used for supporting catalytically active metal components. Examples of possible inorganic oxide materials include alumina, silica-alumina, magnesia, zirconia, boria, titania, and mixtures of any two or more of such inorganic oxides. Preferred inorganic oxides for use in forming the support material are alumina, silica-alumina and mixtures thereof. However, most preferred is alumina.

The catalytically active metal compound is selected from group VI metals (e.g., chromium (Cr), molybdenum (Mo), and tungsten (W)) and group IX and X metals (e.g., cobalt (Co) and nickel (Ni)). Phosphorus (P) is also a desirable metal component. For group VI metals, the metal salt comprises a group VI metal oxide or sulfide. Preferably, the metal salt of a group VI metal comprises ammonium heptamolybdate and ammonium dimolybdate. For group IX and X metals, the metal salt comprises a group IX or X metal acetate, formate, citrate, oxide, hydroxide, carbonate, nitrate, sulfate, and two or more thereof. Preferred metal salts are metal nitrates, for example, nitrates of nickel or cobalt or both.

The weight percentage of the catalytically active metal compound incorporated into the support material depends on the application. The range of group VI metal (preferably molybdenum) in the support material is 5 to 50 wt%, preferably 8 to 40 wt%, and most preferably 12 to 30 wt%. The range of group IX and X metals (preferably nickel) in the support material is 0.5 to 20 wt%, preferably 1 to 15 wt%, and most preferably 2 to 12 wt%. The weight percentages of the metals cited above are based on the dry support material and the metal as element, regardless of the actual form of the metal.

Any suitable amine compound may be used as long as it provides the desired catalytic properties. As the term is used herein, an amine or amine compound is a molecule having an amino functional group, whereby the nitrogen atom is bonded with up to three individual hydrogen atoms or a grouping of one, two or three atoms. Examples of desirable amine components are molecules selected from the group of compounds consisting of: an ether amine compound, an alkyl or alkenyl amine compound, or an amine oxide compound.

The non-amine containing polar additive of the hydroprocessing catalyst comprises the polar additive compounds described in U.S. patent publication No. US 2010/0236988, however, does not comprise those polar additive compounds that are heterocompounds having amino functional groups or sulfur atoms.

Preferably, the relative weight ratio of the amine-free polar additive to the amine compound incorporated into the metal-loaded support material is in the range of up to 10:1(10 parts by weight of the amine-free polar additive to 1 part by weight of the amine compound), for example, 0:01 to 10: 1. More typically, the weight ratio of the amine-free polar additive to the amine compound should be in the range of 0.1:1 to 9: 1. Preferably, the weight ratio is in the range of 0.2:1 to 8:1, more preferably in the range of 0.2:1 to 7:1, and most preferably in the range of 0.25:1 to 6: 1.

The combination of the amine component and the polar additive without the amine component in the metal-loaded support material provides a hydroprocessing catalyst with catalytic properties that are superior to typical compositions comprising a support material loaded with an active metal precursor and having either the amine component alone or the non-amine containing polar additive alone. To obtain the beneficial effect of combining the amine component and the amine-free polar additive, the relative ratios of the two components incorporated into the support material should be within the ranges described above.

The hydrotreating conditions carried out at step (b) often depend on the desired level of conversion, the type of catalyst carried out, and the level of contaminants in the DAO feed, among other factors. Suitable reaction temperatures range from 250 to 480 ℃, preferably from 280 to 450 ℃, and more preferably from 350 ℃ to 420 ℃. Suitable reaction pressures are from 30 to 250 bar. Preferably, the reaction pressure is in the range of 110 to 180 bar, and more preferably in the range of 120 to 170 bar. The Liquid Hourly Space Velocity (LHSV) is suitably in the range of from 0.2 to 10 hours^-1Preferably in the range of 0.2 to 2.0 hours^-1And more preferably in the range of 0.2 to 1.0 hour^-1Within the range of (1).

Hydrocracking

At step (c), contacting the hydrotreated product of step (b) with hydrogen in the presence of a hydrocracking catalyst system within the reactor to produce a hydrocracked product. To maintain weight, at least 15% to about 20% of the long chain hydrocarbon molecules of the hydrotreated product boiling at or above 380 ℃ during hydrocracking are converted to components boiling below 380 ℃. The hydrocracking process of the present invention is well known in the art and involves combining catalytic cracking and hydrogenation steps to break longer chain hydrocarbon molecules and cloud precursors to simpler or shorter chain molecules.

As known to those skilled in the art, the reactor of the present invention has a suitable configuration and is defined by one or more reactor zones containing one or more beds of hydrocracking catalyst. More particularly, the reactor comprises a combination of a hydrotreating catalyst and a hydrocracking catalyst configured to perform a multi-stage process in a suitable configuration, more preferably at least a three-stage process comprising a first hydrotreating stage, a second hydrocracking stage, and a third hydrotreating stage. As will be understood by those skilled in the art, the multi-stage process is not limited to the configurations described herein, but may include additional or fewer stages to achieve desired results.

The first and third stages are hydrotreating stages to reduce and/or remove any remaining nitrogen, sulfur, and unsaturated compounds from the hydrotreated product in the presence of a hydrotreating catalyst. The hydrotreating catalyst used is as previously described for step (b) and comprises a support material loaded with a catalytically active metal compound, an amine compound and a polar additive which is free of amines.

Hydrocracking of the hydrotreated product occurs in the second stage in the presence of a hydrocracking catalyst, as disclosed in U.S. patent No. 9,199,228, which is incorporated herein by reference. The hydrocracking catalyst embodies a strong cracking function and comprises a porous support impregnated with a hydrogenation component, suitably a group VIII (preferably cobalt, nickel, iridium, platinum and/or palladium) and/or group IVB (preferably molybdenum and/or tungsten) catalytically active metal.

The porous support of the hydrocracking catalyst comprises an amorphous binder and zeolite Y. The amorphous binder comprises any refractory inorganic oxide or mixture of oxides. Typically, this is alumina, silica-alumina or a mixture of two or more thereof. However, it is also possible to use zirconia, clay, aluminum phosphate, magnesia, titania, silica-zirconia and silica-boria. Most preferably the amorphous binder is silica-alumina. The amorphous silica-alumina preferably contains silica present in an amount ranging from 25 wt% to 95 wt%, based on total carrier weight. More preferably, the amount of silica in the support is greater than 35 wt%, and most preferably at least 40 wt%. Suitable amorphous silica-alumina products for use in preparing the porous supports of the present invention include 45 wt% silica and 55 wt% alumina and are commercially available.

Preferred zeolite Y materials comprise zeolite Y having a silica to alumina ratio (SAR) greater than 10, especially a unit cell size (a)_O) Ultrastable zeolite y (usy) or very ultrastable zeolite y (vusy) less than 2.440nm (24.40 angstroms), in particular less than 2.435nm (24.35 angstroms), and SAR greater than 10, in particular greater than 10 and up to 100. As used herein, the term SAR isRefers to the molar ratio of silica to alumina contained in the framework of the zeolite.

Suitable zeolite Y materials are known and described, for example, in EP247678, EP247679 and WO 2004/047988. Preferred VUSY zeolites of EP247678 or EP247679 are characterized by a unit cell size of less than 2.445nm (24.45 angstroms) or 2.435nm (24.35 angstroms), a water absorption capacity (at 25 ℃ and 0.2p/p_OValue) is at least 8 wt% of the zeolite and a pore volume of at least 0.25ml/g, wherein between 10% and 60% of the total pore volume consists of pores having a diameter of at least 8 nm. Most preferred are the low unit cell size, high surface area zeolite Y materials described in WO 2004/047988. Such materials can be described as having a SAR greater than 12 and a unit cell size in the range of 24.10 to 95 as measured by the BET method and ATSM D4365-95 using a nitrogen adsorption of 0.03p/po valueAnd a surface area of at least 850m²Zeolite Y per gram.

Although USY and VUSY zeolites are preferred for use in the present invention, other forms of Y zeolites are also suitable for use, for example, ultrahydrophobic Y zeolites.

In other embodiments, the porous support of the present invention may comprise additional zeolites in addition to zeolite Y described above. Preferably, the additional zeolite is selected from zeolite beta, zeolite ZSM-5 or zeolite Y having a unit cell size and/or SAR other than the zeolites described above. The additional zeolite is preferably zeolite beta. The additional zeolite may be present in an amount up to 20 wt%, based on total carrier weight, but preferably the additional zeolite is present in an amount of 0.5 wt% to 10 wt%.

The amount of all zeolites in the porous carrier ranges from 2 wt% to 70 wt% and the amount of amorphous binder ranges from 8 wt% to 30 wt% based on the total carrier weight. Preferably, the amount of all zeolites in the porous support ranges from 5 wt% to 50 wt%, preferably from 10 wt% to 50 wt%, based on total support weight.

The hydrogenation component of the hydrocracking catalyst comprises a group VIB, preferably molybdenum and/or tungsten, and a group VIII metal, preferably cobalt, nickel, iridium, platinum and/or palladium, and oxides and sulfides thereof. The hydrocracking catalyst will preferably contain at least two hydrogenation components, more particularly a combination of molybdenum and/or tungsten with cobalt and/or nickel. Preferred combinations are nickel/tungsten and nickel/molybdenum, wherein advantageous results are obtained when these metal combinations are used in the sulphide form. The hydrocracking catalyst according to the present invention may contain up to 50 parts by weight of a hydrogenation component, calculated as metal per 100 parts by weight (dry weight) of the total weight of the catalyst composition. The hydrocracking catalyst may contain, for example, 2 to 40 parts by weight, more preferably 5 to 30 parts by weight, especially 10 to 20 parts by weight, of one or more group VIB metals and/or 0.05 to 10 parts by weight, preferably 0.5 to 8 parts by weight and more preferably 1 to 6 parts by weight, of one or more group VIB and group VIII metals per 100 parts by weight (dry weight) of the total weight of the catalyst composition of the metals.

The hydrocracking catalyst used in the present invention, in which 50% of the total pore volume of the hydrocracking catalyst is present in pores having a diameter of 4 to 50nm, provides improved contaminant removal properties as well as improved activity and selectivity. The acidity of the hydrocracking catalyst as measured by exchange with fully deuterated benzene is 20 micromoles/gram or less and, therefore, the acidity is lower than most known catalysts. The acidity is preferably at most 15, preferably at most 12, more preferably at most 10, and most preferably at most 8 micromoles per gram. Although the reduction in acidity generally results in a reduction in hydrocracking activity, the presently described hydrocracking catalysts surprisingly provide increased gas oil selectivity at the same activity.

As described herein, hydrocracking process conditions depend on the desired conversion level, the level of contaminants in the DAO feed, and other factors. Suitable hydrocracking process conditions are known to those skilled in the art. In the examples, common hydrocracking conditions comprise a reaction temperature in the range of 250-500 ℃, suitably 350-475 ℃; a reaction pressure in the range of from 35 to 250 bar, suitably 100 and 200 bar; and 0.2 to 10 hours^-1Preferably in 0.5-1.5 hours^-1Weight Hourly Space Velocity (WHSV) in the range. The hydrocracking process conditions also include a weighted average bed temperature in the range of 350 ℃ and 420 ℃(WABT) and a gas-oil ratio ranging from 500NI/kg to 1500 NI/kg.

Hydrocracking reaction conditions are set to provide the desired conversion of hydrotreated products boiling at or above 380 ℃ to lower boiling (i.e., below 380 ℃) products. Typically, the target conversion is at least 50%. Preferably, the conversion of the hydrotreated product exceeds 60%, and most preferably, the conversion is greater than 75%.

Distillation system I

The hydrocracked product produced at step (c) may first be passed to a gas-liquid separator before being passed to a distillation unit at step (d). The gas-liquid separator separates the hydrocracked product into a gas phase and a liquid phase under process conditions comprising: the temperature ranges from about 100 ℃ to about 350 ℃, more suitably from about 130 ℃ to about 240 ℃, and the pressure ranges from about 1 bar to about 50 bar, and more suitably from 1.5 bar to about 10 bar. The gaseous phase of the hydrocracked product may comprise contaminants, such as hydrogen sulfide (H), which are discharged from the gas-liquid separator as contaminated hydrogen-containing gas₂S) and ammonia (NH)₃). In a preferred embodiment, at least 50% of the NH present in the hydrocracked product entering the gas-liquid separator is removed₃And H₂And S. Preferably, at least 80%, more preferably at least 90%, and most preferably at least 95% of the NH present in the hydrocracked product is removed₃And H₂And S. In addition, other impurities and contaminants, such as methane (CH), may be removed at step (d)₄) Ethane (C)₂H₆) Liquefied Petroleum Gas (LPG), naphtha and gas oil and NH₃And H₂S。

The separated liquid phase of the hydrocracked product flows into any suitable distillation unit, preferably a vacuum distillation unit or vacuum column, to be separated into fractions, e.g. lighter hydrocracked products and a heavy oil stream. The lighter hydrocracked products comprise lower boiling light distillates and middle distillates at temperatures in the range of 140 to 410 ℃. The light distillate and middle distillate may comprise the following: naphtha, which contains hydrocarbons boiling above about 100 ℃ to below about 130 ℃, kerosene, which contains hydrocarbons boiling above about 130 ℃ to below about 290 ℃, and diesel, which contains hydrocarbons boiling above about 290 ℃ to below about 380 ℃.

Preferably, the heavy oil stream comprises hydrotreated/hydrocracked DAO, i.e., hydrogen wax. Hydrogen waxes are suitable feedstocks for use in dewaxing or other hydrotreating techniques performed during heavy base oil production. The hydrogen wax fractionated and recovered at step (d) is a liquid product having a kinematic viscosity in the range of 4.0 to 20cSt, a viscosity index of at least 120, and a nitrogen content in an amount in the range of at least 0.01 to 20ppm and a sulfur content in an amount in the range of at least 0.05 to 100ppm and a boiling point in the range of about 330 ℃ to about 700 ℃.

In other embodiments, different and/or additional distillation and separation systems including atmospheric distillation units, strippers, fractionators, or flash separators may be implemented based on the desired level of separation and process conditions, as well as other factors.

Catalytic dewaxing/hydrofinishing

The hydrogen wax recovered at step (d) is used as a feedstock during catalytic dewaxing to further produce the base oil product of the present invention. However, the recovered hydrogen wax may still contain waxy compounds (e.g., cloudy precursors, normal paraffins, isoparaffins, etc.), aromatics, and other contaminants. Hydrogen waxes, including such waxy and aromatic compounds, when used as a feed, often produce base oil products that include high pour and cloud points and a visually hazy appearance. Such base oil products are generally unsuitable for use and storage under cryogenic conditions due to the formation of solid waxy crystals formed therein.

In an embodiment, during catalytic dewaxing at step (e), the hydrogen wax is catalytically dewaxed in the presence of the unique mixture of noble metal based catalysts to reduce and/or remove any remaining waxy compounds from the hydrogen wax. The mixture of noble metal-based catalysts described herein selectively removes and/or converts waxy compounds of hydrogen wax to dewaxed products comprising reduced pour and cloud points.

At step (e), the hydrogen wax is contacted with hydrogen in the presence of a noble metal-based catalyst composition contained within a reactor (e.g., a hydrofinishing/isomerization dewaxing reactor). The noble metal-based catalyst composition comprises both a dewaxing catalyst and a hydrofinishing catalyst to remove remaining haze precursors, other wax compounds and aromatic compounds.

Preferably, the dewaxing catalyst comprises a fractionated mixture of noble metal isomerization dewaxing catalysts ("fractionated mixture") comprising a ZSM-12 zeolite based catalyst ("ZSM-12"), a modified ZSM-12 zeolite based catalyst ("modified ZSM-12") and an EU-2 and/or ZSM-48 zeolite based catalyst ("EU-2 and/or ZSM-48"). ZSM-12 and modified ZSM-12 have similar characteristics, and thus, the description provided herein describes two catalysts. Modification of a catalyst is a process that mitigates the deleterious effects of catalyst contamination (e.g., oxygen, water vapor, metals, etc.) without significantly reducing catalyst activity or selectivity. The modification process comprises contacting the catalyst and/or the surface of the catalyst with the contaminant such that the contaminant is adsorbed by the catalyst and subsequently released from the catalyst. Thus, unlike modified ZSM-12, ZSM-12 is not subjected to the modification process.

As described herein, a graded mixture is defined as comprising a concentration gradient, i.e., a non-uniform concentration or gradient difference in the concentration of each catalyst passing through one or more catalyst beds. The phrase "through one or more catalyst beds" is defined to include movement from the inlet to the outlet of the catalyst bed. The concentration gradient of an embodiment may be achieved within a single catalyst bed, separate catalyst beds, separate reactors, or multiple reactors.

As a first example, the concentration of ZSM-12 is decreased and the concentration of modified ZSM-12 and EU-2 and/or ZSM-48 is increased in a linear or non-linear manner through the catalyst bed within a single catalyst bed. In this regard, the concentration of ZSM-12 is highest at the inlet or inlet region of the catalyst bed, and thus the concentration of ZSM-12 decreases linearly or non-linearly from the inlet to the outlet of the catalyst bed. In addition, the concentration of the modified ZSM-12 and EU-2 and/or ZSM-48 is highest at the outlet or outlet region of the catalyst bed, so that the concentration of the modified ZSM-12 and EU-2 and/or ZSM-48 increases linearly or non-linearly through the catalyst bed from the inlet to the outlet. For example, in a top-down flow reactor, the inlet would be in the upper region of the catalyst bed that is first contacted with the hydrogen wax, and the outlet would be in the lower region or bottom of the catalyst bed.

As a second example, within a separate catalyst bed, in a separate reactor or reactors, the concentration of ZSM-12 decreases in a non-linear manner and the concentration of modified ZSM-12 and EU-2 and/or ZSM-48 increases in a non-linear manner when moving from one catalyst bed to the next catalyst bed or beds.

As a third example, one or more catalyst beds may comprise two or more separate zones, wherein the zones are in a stacked configuration. Each zone in the catalyst bed comprises a mixture of ZSM-12, modified ZSM-12 and EU-2 and/or ZSM-48 such that the sum of the zones defines a gradient decrease in the concentration of ZSM-12 and a gradient increase in the concentration of modified ZSM-12 and EU-2 and/or ZSM-48 in a stepwise non-linear manner through the catalyst bed from one zone to the next.

The preceding examples are only a few of the various catalyst configurations found within one or more catalyst beds and should not be construed or otherwise used to limit the scope of the present invention. For example, one skilled in the art can select the modified ZSM-12 having the highest concentration at the inlet and the ZSM-12 and EU-2 and/or ZSM-48 having the highest concentration at the outlet. The choice of catalyst configuration may depend on various process related characteristics, such as the characteristics of the DAO feed, the characteristics of the hydrogen wax, and the nature of the linear or non-linear concentration gradient required to produce a haze-free heavy base oil at 0 ℃, among other considerations.

Several gradient mixtures can be prepared with different ratios of ZSM-12 to modified ZSM-12 to EU-2 and/or ZSM-48. The selected fractionation mixture is then loaded into one or more catalyst beds to achieve the desired concentration gradient for each of the ZSM-12, modified ZSM-12 and EU-2 and/or ZSM-48 catalysts. It has surprisingly been found that higher base oil yields are obtained using a fractionated mixture as compared to using a non-gradient mixture (i.e. a constant concentration of the selected catalyst) through one or more catalyst beds.

The SAR of both ZSM-12 and modified ZSM-12 zeolite based catalysts is high enough to exhibit exemplary high activity catalytic properties while providing high yields of heavy lubricating base oil. In embodiments, the ZSM-12 and modified ZSM-12 have a SAR of at least 50: 1. Preferably, the SAR is greater than 60:1 or greater than 70:1 or greater than 75: 1. The upper limit of the SAR for ZSM-12 and modified ZSM-12 is preferably at most 250:1, more particularly at most 200:1, and more preferably less than 150:1, especially less than 110: 1. If the SAR of the synthesized ZSM-12 is too low, further dealumination may be performed using methods known in the art to provide a dealuminated ZSM-12 having the desired SAR.

The ZSM-12 and modified ZSM-12 should be present in an amount of at least 10 wt% and at most 70 wt% of the total weight of the classified mixture.

The binder content of the ZSM-12 and modified ZSM-12 may range from at least 30 wt% and not more than 90 wt% of the total weight of the classified mixture. Preferably, the binder content of the ZSM-12 and modified ZSM-12 is at most 60 wt%, more preferably at most 50 wt%, and more particularly at most 40 wt% of the total weight of the classified mixture. It is further preferred that the binder content of the ZSM-12 and modified ZSM-12 is at least 15 wt%, and more preferably at least 20 wt% of the total weight of the classified mixture. Further, it is preferred that neither the ZSM-12 nor the modified ZSM-12 contain any additional zeolite therein.

EU-2 and/or ZSM-48 of the fractionated mixture may comprise a refractory oxide binder that is substantially free of alumina. The SAR of EU-2 and/or ZSM-48 is preferably at least 60, more preferably at least 70, more particularly at least 80, most preferably at least 90. The SAR of EU-2 and/or ZSM-48 is preferably at most 300, more particularly at most 250, more particularly at most 200, most particularly at most 150.

EU-2 and/or ZSM-48 preferably comprises at most 70 wt%, more particularly at most 65 wt%, more particularly at most 60 wt%, most preferably at most 55 wt% of the fractionated mixture. Further, it is preferred that the amount of EU-2/ZSM-48 is at least 15 wt%, more specifically at least 20 wt%, more specifically at least 25 wt%, most specifically at least 30 wt%.

Optionally, additional zeolite may be present in EU-2 and/or ZSM-48, preferably in an amount of up to 50 wt%, based on the total weight of EU-2 and/or ZSM-48 present in the total weight of the fractionated mixture.

The binder content of EU-2 and/or ZSM-48 may range from at least 30 wt% but not more than 85 wt% of the total weight of the fractionated mixture. In the present invention, reference to a binder includes refractory oxide binders. Examples of refractory oxide binder materials are alumina, silica, zirconia, titania, germanium dioxide, boria, and mixtures of two or more (e.g., silica-zirconia and silica-titania). Preferred binders are titanium dioxide, zirconium oxide and/or silicon dioxide, wherein silicon dioxide is a preferred binder for the fractionated mixture.

In embodiments, the noble metal component of the ZSM-12, modified ZSM-12 and EU-2 and/or ZSM-48 is preferably selected from the group of noble metals consisting of palladium and platinum. However, the preferred noble metal is platinum.

The noble metal content of each catalyst in the classified mixture may range up to about 3 wt% based on noble metal as an element, regardless of its actual form and the total weight of the classified mixture. Preferably, the concentration of the noble metal component present in the fractionated mixture ranges from 0.1 wt% to 3 wt%. More preferably, the concentration of the noble metal component ranges from 0.2 wt% to 2 wt%, and most preferably ranges from 0.3 wt% to 1 wt%.

The fractionated mixture of the invention is well suited for dewaxing hydrocarbon feedstocks, such as hydrogen wax, to increase the removal of waxy compounds that form wax crystals and thus increase visual haze in the base oil product. Thus, the system may be used in any conventional series, including the section used to dewax hydrocarbon compound feedstocks (e.g., hydrogen wax).

As previously mentioned, the noble metal-based catalyst composition of the hydrofinishing/isomerization dewaxing reactor may contain a hydrofinishing catalyst to remove and/or reduce the aromatics content. Preferably, the hydrofinishing catalyst is a noble metal aromatic compound hydrogenation catalyst comprising at least one noble metal component incorporated onto a supporting carrier comprising zirconia and another inorganic oxide component. Preferably, the noble metal aromatic hydrogenation catalyst comprises 0.01 to 5 wt% of a noble metal selected from the group consisting of platinum, palladium and combinations thereof, 1 to 30 wt% of zirconia and 60 to 99 wt% of an inorganic oxide selected from the group consisting of silica, alumina and silica-alumina. Commercially available hydrofinishing catalysts are disclosed in U.S. patent No. 7,737,074, which is incorporated herein by reference.

Zirconium and inorganic oxide constitute the support carrier. In particular, zirconia and inorganic oxides are co-milled to form a mixture that subsequently forms agglomerate particles, which are dried and calcined to further form calcined particles. The calcined particle is suitable for use as a support for a noble metal aromatic hydrogenation catalyst.

The zirconium compound used in the supporting carrier may be selected from the group consisting of oxides, nitrates, silicates, carbonates, acetates, chlorides, hydroxides and hydrates of zirconium. Specific examples of possible suitable zirconium compounds to be co-milled with the inorganic oxide include zirconyl chloride (zroc1.8ho); zirconyl hydroxide (zro (oh)); zirconyl sulfate (zro (so)); sodium zirconyl sulfate (zro (so). NaSO); zirconyl carbonate (zro (co)); ammonium zirconyl carbonate ((NH4)2ro (co)); zirconyl nitrate (zro (no)); zirconyl acetate (zro (cho)); zirconyl ammonium acetate ((NH4)2ro (cho)); zirconyl phosphate (zro (hpo)); zirconium tetrachloride (ZrOl); zirconium silicate (ZrSiO); and zirconium oxide (ZrO). Preferred zirconium compounds include ammonium zirconyl carbonate and zirconyl acetate.

The inorganic oxide material used in the support carrier may be selected from the group of inorganic oxides consisting of silica, alumina, silica-alumina, and any combination of two or more thereof. Preferred inorganic materials to be combined with the zirconium compound are selected from silica or alumina or a combination of both.

When the supporting carrier contains both silica and alumina in relative amounts such that the molar ratio of SAR ranges from 1:10 to 10:1, the supporting carrier contains zirconium as an element in an amount ranging from 0.5 to 20 wt%, preferably from 1 to 15 wt%, and most preferably from 2 to 10 wt%, wherein the weight percentages are based on the total weight of the supporting carrier and are calculated assuming that zirconium is a metal.

When the SAR of the supporting carrier is greater than 10:1, including when the supporting carrier is substantially free of alumina or silica alone used in combination with zirconia, the amount of zirconium content of the supporting carrier as an element ranges from 3 to 30 wt%, preferably from 5 to 25 wt%, most preferably from 7 to 20 wt%, where the weight percentages are based on the total weight of the supporting carrier and are calculated assuming that zirconium is a metal.

The surface area of the noble metal aromatic hydrogenation catalyst is generally in the range of 200 to 500m²/gm, preferably 250 to 450m²/gm, and more preferably 300 to 400m²And/gm. The pore volume of the noble metal aromatic hydrogenation catalyst, as determined by using standard mercury porosimetry methods, typically ranges from 0.7 to 1.3ml/gm, and the median pore diameter of the noble metal aromatic hydrogenation catalyst ranges fromTo

Preferred noble metal aromatic hydrogenation catalysts comprise both a platinum component and a palladium noble metal component, wherein the weight ratio of elemental palladium to platinum is from 1:10 to 10:1, preferably from 1:2 to 5:1, and most preferably from 1:1 to 3: 1. Thus, the noble metal incorporated into the support carrier should provide the catalyst composition with a noble metal content in the range of from 0.01 to 5 wt% for each noble metal, wherein the weight percentages are based on the total weight of the final catalyst composition and calculated as elemental metal. The preferred noble metal content of each noble metal component ranges from 0.1 to 4 wt.%, and most preferably from 0.2 to 3 wt.%.

The noble metal-based catalyst composition of a hydrofinishing/isomerization dewaxing reactor, including a staged mixture and a noble metal aromatic hydrogenation catalyst, can enhance final product performance and quality by removing haze precursors, other wax compounds and aromatics while increasing yield during catalytic dewaxing. In particular, the dewaxed product produced at step (e) comprises a pour point which is preferably at least 40 ℃ and more preferably at least 60 ℃ and which is lower than the pour points of the DAO feed and the hydrogen wax entering the hydrofinishing/isomerization dewaxing reactor.

In a preferred embodiment, the staged mixture and the noble metal aromatic hydrogenation catalyst may be located in the same bed but in separate layers, in separate beds, or each in multiple beds, or within the same reactor, in separate reactors, or each in multiple reactors. In addition, the noble metal aromatic hydrogenation catalyst may be loaded before or after loading the fractionated mixture into the hydrofinishing/isomerization dewaxing reactor.

Catalytic dewaxing conditions are known in the art and generally involve the following: the reaction temperature is in the range of 200-500 deg.C, suitably 250-400 deg.C, the reaction pressure is in the range of 10-200 bar, suitably 15-100 bar, more suitably 15-65 bar, and the Weight Hourly Space Velocity (WHSV) is in the range of 0.2-10 hours^-1Suitably from 0.2 to 5 hours^-1More suitably from 0.5 to 3 hours^-1. In addition, catalytic dewaxing conditions can include a Weighted Average Bed Temperature (WABT) in the range of 320-370 ℃ and a gas-oil ratio in the range of 500-1500 NI/kg.

Hydrorefining

The dewaxed product is hydrofinished in the presence of a hydrofinishing catalyst at step (f) to produce a hydrofinished product. The hydrofinishing catalyst is preferably a noble metal aromatic hydrogenation catalyst as previously described in relation to the hydrofinishing catalyst used at step (e). Hydrofinishing processes are well known in the art and involve the removal of mono-and poly-cyclic aromatics and other aromatics from the dewaxed product to ensure final product stability, such as oxidation stability.

Generally, the hydrofinishing process is carried out under the following conditions: the reaction temperature is in the range of about 125 to about 390 ℃, the reaction pressure is in the range of about 70 to about 200 bar, the Weighted Average Bed Temperature (WABT) is in the range of about 220-^-1. The severity of the hydrofinishing reaction should be kept within a low range if possible, since an increase in reaction conditions may lead to a gradual decrease in the viscosity of the haze-free heavy base oil composition at 0 ℃, and hence to a decrease in the yield of heavy oil.

Distillation system II

The hydrofinished product produced at step (f) is passed to a distillation unit at step (g) and fractionated by conventional means, for example by vacuum distillation at atmospheric or reduced pressure. Similar to the previous distillation system at step (d), the hydrofinished product may first enter a gas-liquid separator and then flow to the distillation unit at step (g) to be fractionated into lighter products and a heavy oil stream.

Any suitable vacuum distillation unit or vacuum column known to those skilled in the art may be used to distill and separate the hydrofinished product into fractions comprising a light distillate fuel product, a middle distillate fuel product, and a heavy base oil composition. The fractionated light distillate fuel product can comprise a viscosity in the range of 2-3cSt at 100 ℃ and a boiling point below about 390 ℃, and the fractionated middle distillate fuel product can comprise a viscosity in the range of 4.5-7.0cSt at 100 ℃ and a boiling point in the range of 390-510 ℃. The heavy base oil composition is a haze free heavy base oil at 0 ℃ with improved cold flow properties.

Recovery of group II/III heavy base oils

At step (h), a fractionated, haze-free heavy base oil at 0 ℃ is recovered. The combination of these process steps in the presence of the above catalyst composition produces a haze-free heavy base oil at 0 ℃, comprising reduced pour and cloud points, low contaminant content and increased viscosity index and kinematic viscosity. In particular, the haze free heavy base oil at 0 ℃ is a group II/III heavy base oil, suitably containing sulphur in an amount of less than 5ppm, preferably less than 1ppmw, and containing nitrogen in an amount of less than 5ppm, preferably less than 1 ppm. The recovered haze-free heavy base oil composition at 0 ℃ comprises: a kinematic viscosity at 100 ℃ in the range of 15-21 cSt; a viscosity index ranging from 95 to 119 when prepared as a group II base oil, and a viscosity index greater than 120 when prepared as a group III base oil; a pour point of less than-12 ℃; a cloud point of less than-18 ℃; and a total aromatics content of 2 wt% or less, and a total saturates content of at least 98 wt%. More preferably, the recovered haze free heavy base oil composition at 0 ℃ comprises: a kinematic viscosity at 100 ℃ in the range of 19 to 20 cSt; a viscosity index ranging from 95 to 119 when prepared as a group II base oil, and a viscosity index greater than 120 when prepared as a group III base oil; a pour point of less than-24 ℃; a cloud point of less than-21 ℃; and a total aromatics content of 1 wt% or less, and a total saturates content of at least 99 wt%.

The base oil product may contain a sufficient amount of haze precursors even after performing the hydrotreating step known to the person skilled in the art. In this case, wax crystals (e.g., solid hydrocarbon crystals) often form in the base oil when subjected to low temperatures and/or upon storage to produce an undesirable cloudy appearance. The extent of wax formation is characterized by cold flow properties (such as pour point and cloud point) and indicates the utility of the base oil for certain applications at low temperatures. Pour point refers to the temperature at which the oil begins to flow, and cloud point refers to the temperature at which the oil begins to cloud due to the formation of wax crystals.

However, the haze-free heavy base oil at 0 ℃ and the process for its production supports a reduced wax formation and haze formation due to the lower pour and cloud points, in addition to which the performance is generally improved compared to conventional heavy base oil products. As an indication of improved cold flow properties, wax haze tests were performed on a 0 ℃ haze free heavy base oil. The test is a pass/fail determination to determine whether the recovered haze-free heavy base oil at 0 ℃ retains its haze-free appearance when stored at low temperature and in an unstirred state (i.e., undisturbed) during an extended test period. In particular, the test is performed at a temperature of 0 ℃ during a test period of at least 5 hours, preferably at least 7 hours, without interference or agitation (e.g., without stirring). It was surprisingly found that the haze-free heavy base oils at 0 ℃ of the present invention do not form any wax crystals when subjected to the wax haze test and thus retain a cloudy appearance for an extended period of time, e.g., 5 hours, preferably 7 hours, when stored undisturbed at 0 ℃.

Thus, the present example provides an improvement over known base oils and production methods by: the DAO feed is subjected to a series of steps in the presence of a unique catalyst composition to produce a haze-free heavy base oil at 0 ℃ with reduced pour and cloud points. As shown by its ability to pass the wax haze test, a haze free heavy base oil at 0 ℃ is unable to form solid wax compounds at lower temperatures. This improvement in cold flow properties exhibited by the haze-free heavy base oils at 0 ℃ of the present invention makes them ideal candidates for use during heavy, low temperature applications over conventional base oils.

In addition to improved cold flow properties, the process of the present invention, performed in the presence of the catalyst composition, further provides a haze-free heavy base oil at 0 ℃ comprising low contaminants and aromatics, contributing to overall product stability. The haze free heavy base oil at 0 ℃ of the present invention further comprises additional advantages compared to conventional heavy base oils. It has surprisingly been found that the process examples produce a high ratio of haze-free heavy base oil at 0 ℃ relative to light base oil to provide an overall product yield of at least 99.8 wt%. In addition, the haze-free heavy base oil at 0 ℃ comprises a saybolt colour of +20 or higher, preferably +24 or higher, more preferably +26 or higher. The "saybolt colour" referred to herein means a value measured according to JIS K2580 "Petroleum product-colour test method-saybolt colour test method" and includes the purpose of removing substances that inhibit oxidation stability.

The figure shows an exemplary embodiment of a process for the production of haze free heavy base oil at 0 ℃ from Deasphalted (DAO) feed. The pure DAO feed flows through line 102 into the pretreatment unit 104. Optionally, the feed may comprise a blend of fractions of DAO, Vacuum Gas Oil (VGO), and hydrogen wax, in any combination thereof. The pretreatment unit 104 may comprise at least two commercially available catalyst beds, including a hydrodemetallization catalyst and a hydrotreating catalyst to remove nitrogen, sulfur, and aromatics, as well as other impurities. The hydrotreated product is withdrawn from the pretreatment unit 104 via line 106 to flow to the hydrocracker unit 108. The hydrotreated product is subjected to suitable hydrocracking conditions to crack at least a portion of the heavy hydrocarbons and cloudy precursors within the DAO feed into lower boiling hydrocarbons, thereby producing a hydrocracked product. The hydrocracker unit 108 may contain hydrotreating and hydrocracking catalysts, for example, metal-based hydrodenitrogenation catalysts, hydrodesulfurization catalysts, and hydrocracking catalysts.

The hydrocracked product passes from the hydrocracker unit 108 through line 110 to a first vacuum distillation unit 112 to be distilled and separated into various fractions. Residual products, including light distillates and middle distillates, are collected via line 114 and line 116, respectively, and removed from the first vacuum distillation unit 112. The residual product may comprise ammonia (NH)₃) Hydrogen sulfide (H)₂S), methane (CH)₄) Ethane (C)₂H₆) At least one of Liquefied Petroleum Gas (LPG), naphtha and gas oil, and other contaminants.

A heavy oil stream, hydrogen wax, is separately collected via line 120 for flow to a hydrofinishing/isomerization dewaxing unit 122. In some embodiments, a portion of the hydrogen wax via line 118 can be recycled as a feedstock to the hydrocracking unit 108 to increase the yield of middle distillates including kerosene and diesel products (e.g., ultra low sulfur diesel). In other embodiments, a portion of the middle distillate via line 116 can be mixed with the hydrogen wax via line 120 to flow into the hydrofinishing/isomerization dewaxing unit 122.

The hydrofinishing/isomerization dewaxing unit 122 is charged with a noble metal-based catalyst system consisting of, for example, an aromatic hydrogenation catalyst and a fractionated mixture formulated to produce a heavy base stock oil having improved cold flow properties. The resulting dewaxed product flows from hydrofinishing/isomerization dewaxing unit 122 through line 124 to second hydrofinishing unit 126. The second hydrofinishing unit is charged with a hydrofinishing catalyst, for example, the aromatic hydrogenation catalyst used in unit 122. The hydrofinished product passes through line 128 to a second vacuum distillation unit 130 to be fractionated into various base oils according to desired characteristics (such as use and viscosity grade). In this example, the hydrofinished product was fractionated to provide a haze free heavy base oil 132 at 0 ℃. Additional fractions from the hydrofinished product comprise a light distillate fuel product 134 having a viscosity in the range of 2 to 3cSt at 100 ℃ and a boiling point below about 380 ℃, and a middle distillate fuel product 136 having a viscosity in the range of 4.5 to 7.0cSt at 100 ℃ and a boiling point in the range of 380 ℃ to 600 ℃.

The following examples are intended to illustrate the nature and capabilities of the improvements proposed by the embodiments of the present invention.

Example 1

This example 1 describes a DAO feed treated by this process example to produce a base oil composition of the present invention. Table 1 shows the composition of the DAO feed used in each of the experiments.

Table 1: composition of DAO feed

As described in table 1, during experimental testing, the DAO feedstock was subjected to hydrotreating techniques, including hydrotreating and hydrocracking process steps. The DAO is initially hydrotreated over a hydrotreating catalyst system comprising at least one hydrodemetallization catalyst and at least one hydrotreating catalyst to produce a hydrotreated product. The hydrotreating catalyst includes a support material supporting a catalytically active metal compound, an amine compound, and a polar additive that is free of amines.

Thereafter, the hydrotreated product is subjected to hydrocracking in the presence of a combination of a hydrotreating catalyst and a hydrocracking catalyst configured to perform multi-stage processing in a suitable configuration. The hydrotreating catalyst is as previously described. The hydrocracking catalyst comprises a porous support comprising an amorphous binder and zeolite Y. The porous support is further impregnated with a hydrogenation component, suitably a group VIII (preferably cobalt, nickel, iridium, platinum and/or palladium) and/or group IVB (preferably molybdenum and/or tungsten) catalytically active metal.

After hydrotreating and hydrocracking, a hydrotreated product (i.e., a hydrocracked product) containing a pour point of +27 ℃, 1.4ppm of nitrogen, and 10ppm of sulfur was produced. Table 2 indicates the operating conditions and the main results of the hydrotreating step.

Table 2: production of hydrogenation products (according to the invention)

Comparative example 1

This comparative example 1 presents the results of comparative experimental tests performed using the same DAO feed as presented in table 1. The DAO feed was hydrotreated to have a pour point of +51, and similar nitrogen and sulfur levels, respectively<2ppmw and<30ppmw to match the typical requirements for second stage noble metal isomerization dewaxing and hydrofinishing catalysts according to current practice. The hydrotreating catalyst comprises high activity NiMo/Al₂O₃-a cracking bed of type II hydrotreating catalyst and amorphous silica alumina catalyst. Table 3 indicates the operating conditions and the main results of the hydrotreating step of comparative example 1.

Table 3: production of hydroprocessed effluent (in accordance with the present practice)

Table 4 provides a comparison of the results between the present invention (table 2) and the current practice (table 3).

Table 4: general description after hydrotreatment

When the results presented in table 2 of the present invention are compared with the results of the current practice in table 3, the inventive process performed in the presence of hydrotreating and hydrocracking catalysts produces a hydrocracked product with improved cold flow properties and reduced contaminant removal.

Example 2

The hydrogenated products of table 2 are fractionated to recover hydrogenated/hydrocracked DAO, e.g., hydrogen wax. This example 2 presents experimental test results during catalytic dewaxing of hydrogen wax over a noble metal based catalyst composition to further remove waxy compounds and aromatic compounds during production of a heavy base oil according to the invention. The noble metal-based catalyst composition comprises both a dewaxing catalyst and a hydrofinishing catalyst. The dewaxing catalyst comprises a fractionated mixture of a noble metal isomerization dewaxing catalyst. The hydrofinishing catalyst comprises a noble metal aromatic compound hydrogenation catalyst.

After catalytic dewaxing, a catalytic dewaxed product was produced which contained a pour point of-48 ℃ and a cloud point of-21 ℃. Table 5 indicates the operating conditions and the main results of the catalytic dewaxing step.

Table 5: production of catalytically dewaxed product (according to the invention)

Comparative example 2

This comparative example 2 presents the results of comparative experimental testing after stripping of the contaminants and light products (ASTM D2887IBP ═ 372 ℃) of the hydrotreated effluent described in table 3. The hydrotreated effluent was catalytically dewaxed over a shell commercial dewaxing catalyst system developed specifically for dewaxing of deep hydrotreated feedstocks for the production of base oils II and III. Table 6 indicates the operating conditions and the main results of the catalytic dewaxing step of comparative example 2.

Table 6: production of catalytically dewaxed product (in accordance with the present practice)

Table 7 provides a comparison of the results between the present invention (table 5) and the current practice (table 6).

Table 7: overview after catalytic dewaxing

Catalytic dewaxing step	According to the invention (Table 5)	According to the present practice (Table 6)
			Catalyst and process for preparing same	Noble metal-based catalyst composition	Shell commercial dewaxing catalyst system
370 ℃ C. + yield,% wfo (step 2)	75.0	78.0
			Vk100，cSt	10.30	8.81
Viscosity index	118	115
			Pour point, DEG C	-48	-27
Cloud point,. degree.C	-21	+9

When comparing the results presented in table 5 of the present invention with the results of the current practice in table 6, the process of the present invention, performed in the presence of a noble metal-based catalyst composition (a fractionated mixture comprising a dewaxing catalyst), produces a catalytically dewaxed product with improved cold flow properties comprising a pour point of-48 ℃ and a cloud point of-21 ℃. In contrast, during current practice, the products produced include a higher pour point of-27 ℃ and a higher cloud point of +9 ℃.

Example 3

This example 3 presents the results of experimental testing during hydrofinishing of a catalytically dewaxed product, as described in table 5. The catalytically dewaxed product is hydrofinished in the presence of a noble metal aromatics hydrogenation catalyst to remove mono-and poly-cyclic aromatics, as well as other aromatics during the production of the heavy base oil of the present invention. After hydrofinishing, the resulting hydrofinished product comprised a pour point of-45 ℃ and a cloud point of-18 ℃ with a reduced nitrogen content of 1.0ppmw and a reduced sulphur content of 3.5 ppmw. Table 8 shows the operating conditions and the main results of the hydrofinishing step to produce a hydrofinished product.

Table 8: production of hydrogenation products (according to the invention)

Comparative example 3

This comparative example 3 presents the results of comparative experimental testing of the dewaxed product from a hydrofinishing step using a noble metal hydrofinishing catalyst (LN-5) from Standard corporation (Criterion). Table 9 shows the operating conditions and the main results of the hydrofinishing step of comparative example 3.

Table 9: production of hydrogenation products (in accordance with the present practice)

Table 10 provides a comparison of the results between the present invention (table 8) and the current practice (table 9).

Table 10: overview after hydrofinishing

When comparing the results presented in table 8 of the present invention with the results of the current practice in table 9, the process of the present invention was carried out in the presence of metal-based and noble metal-based catalysts with improved cold flow properties comprising a pour point of-45 ℃ and a cloud point of-18 ℃, as provided in table 9. In contrast, during the current practice, the base oil produced comprised a higher pour point of-12 ℃ and a higher cloud point of +9 ℃ compared to the haze free heavy base oil of the present invention at 0 ℃. In addition, the haze free heavy base oil at 0 ℃ passed the wax haze test compared to a conventionally produced base oil that failed the test.

While the described method may be susceptible to various modifications and alternative forms, the exemplary embodiments discussed above are shown by way of example only. It should be understood that the methods of the present invention are not intended to be limited to the particular embodiments disclosed herein. Furthermore, reference throughout this specification to "one embodiment," "an embodiment," or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. Thus, the phrases "in one embodiment," "in an embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

Although the present invention has been described in detail, it is not intended that such detail be regarded as limitations upon the scope of the invention except as and to the extent that they are included in the accompanying claims.