Heavy base oil without haze at 0℃ and method of manufacturing

Abstract

A method for preparing a base oil composition from a deasphalted oil (DAO) feedstock, wherein the DAO feedstock undergoes hydrogenation, hydrocracking, catalytic dewaxing, hydrofinishing, and fractionation to produce a base oil composition. The base oil composition comprises a heavy base oil that is hazy at 0°C, comprising (a) a dynamic viscosity in the range of 15 to 21 cSt at 100°C, (b) a viscosity index of at least 95, (c) a pour point of less than -12°C, (d) a rolling point of less than -18°C, and (e) a total aromatic content of 2 weight% or less; wherein the heavy base oil that is hazy at 0°C maintains a hazy-free appearance when stored undisturbed at 0°C during a test period.

Description

Technology Field

[0001] The present invention relates to a haze-free heavy base oil at 0°C and a method for producing a heavy base oil from a deasphalted oil feed. Background Technology

[0002] Heavy lubricating base oils used in the formulation of engine lubricants and industrial oils can be produced from suitable hydrocarbon feedstocks derived from the deasphalting of atmospheric or vacuum residues. One example of a hydrocarbon feedstock used in the production of heavy base oils includes deasphalted oil (DAO). DAO is typically subjected to several processing steps, such as hydrotreatment to remove nitrogen, sulfur, metals, and other contaminants, and hydrocracking to reduce the molecular weight of aromatic compounds and haze precursors. Hydrotreatment and hydrocracking can also increase the viscosity index and dynamic viscosity of the resulting base oil product.

[0003] Although considered a suitable feedstock due to its high viscosity, DAO is actually rich in wax compounds that are solid at ambient temperatures and often imparts undesirable high pour points and cloud points to base oil products. These undesirable characteristics can hinder the manufacturing, use, storage, and transportation of such base oils, among other things. Therefore, additional steps including catalytic dewaxing and hydrofinishing of DAO can improve low-temperature flow characteristics and overall product stability by removing wax compounds, thereby reducing the pour point and cloud point of the base oil produced thereafter.

[0004] However, even after catalytic dewaxing of the DAO feedstock, the base oil product may still contain naturally occurring haze precursors, such as paraffin-like wax compounds and other wax compounds. If present in sufficient quantities, particularly if the base oil is left at low temperatures for an extended period, these haze precursors form visual haze in the base oil at ambient temperatures. Visual haze manifests as a milky or cloudy appearance that contributes to the visual degradation and undesirable performance of the base oil product under low-temperature conditions. Haze precursors can also affect the filterability of the base oil or finished lubricating oils containing the base oil.

[0005] Therefore, DAO feedstocks may undergo hydrogenation initially to remove contaminants such as nitrogen, followed by additional dewaxing and distillation steps to remove wax compounds. However, additional and / or more stringent process steps can lower product yields, resulting in a substantial reduction in the proportion of heavy base oils relative to light base oils. A reduction in heavy base oil yields is often undesirable during periods of high demand for such oils.

[0006] Therefore, there is a continuing demand for a base oil composition having improved low-temperature flow characteristics and continuous utility during low-temperature application, and a method of manufacturing the same that provides maximum manufacturing yield.

[0007] The present invention provides a heavy base oil that is hazy-free at 0°C and a method for producing the same. The method comprises the step of providing a deasphalted oil (DAO) feed containing at least 50 wt% of a hydrocarbon that boils above 450°C, an amount of nitrogen in the range of 400 to 2500 ppm or more, an amount of sulfur in the range of 0.5 to 4.0 wt% or more, and an amount of (nickel (Ni)+vanadium (V)) metal content in the range of 2 to 250 ppmw. A portion of the DAO feed is hydrogenated in the presence of a hydrogenation catalyst to produce a hydrogenated product containing an amount of nitrogen in the range of 0.1 to 30 ppmw, an amount of sulfur in the range of 10 to 200 ppmw, and a total absorption amount of at least 30% of the (Ni+V) metal content. The hydrotreated product is hydrocracking in the presence of a hydrocracking catalyst to produce a hydrocracking product fractionated into a light distillate, an intermediate distillate, and a hydrowax. The hydrowax is catalytically dewaxed in the presence of a precious 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 heavy base oil that is haze-free at 0°C and can maintain a haze-free appearance when stored undisturbed at 0°C for a test period of at least 5 hours, preferably at least 7 hours. The recovered fractionated heavy base oil that is haze-free at 0°C is a Group II / III base oil that maintains a haze-free appearance when stored undisturbed at 0°C during the test period.

[0008] The heavy base oil of the present invention, which is haze-free at 0°C, has a dynamic viscosity in the range of 15 to 21 cSt at 100°C, a viscosity index in the range of 95 to greater than 120, a pour point of less than -12°C, a rolling point of less than -18°C, and a total aromatic content of 2 weight% or less. Brief explanation of the drawing

[0009] Specific exemplary embodiments are described in the following detailed description with reference to the drawings. The drawing illustrates an exemplary embodiment of a flow process for producing haze-free heavy base oil from a deasphalted (DAO) feedstock at 0°C. Specific details for implementing the invention

[0010] The present invention discloses a heavy base oil composition that is hazy at 0°C and a method for producing the same. The method comprises producing a heavy base oil that is hazy at 0°C by hydrogenating, hydrocracking, catalytic dewaxing, and hydrofinishing a DAO feed in the presence of precious metal-based and metal-based catalysts. The heavy base oil that is hazy at 0°C comprises a dynamic viscosity in the range of 15 to 21 cSt at 100°C, preferably 19 to 20 cSt at 100°C, a viscosity index in the range of 95 to 119 when produced as a Group II base oil, and a viscosity index greater than 120 when produced as a Group III base oil. Additionally, the heavy base oil that is hazy at 0°C comprises a pour point of less than -12°C, preferably less than -18°C, more preferably less than -24°C, a rolling point of less than -18°C, preferably less than -21°C, and a total aromatic content of less than 2 weight%, preferably less than 1 weight%.

[0011] The 0°C haze-free heavy base oil composition of the present invention comprises a Group II / III lubricating base oil having improved low-temperature flow characteristics, including reduced rolling point and pour point. Additionally, the composition of the present invention maintains a haze-free appearance when stored and / or transported at 0°C without stirring (i.e., undisturbed) for an extended period, e.g., 5 hours, preferably 7 hours. Therefore, the composition of the present invention is desirable for use, storage, and transport activities involving heavy loads and low-temperature applications. In addition to improved low-temperature flow characteristics, the 0°C haze-free heavy base oil of the present invention provides end-product stability characteristics, including reduced contaminants (e.g., nitrogen, sulfur, aromatics), absence of haze formation during low-temperature applications, and higher viscosity index and dynamic viscosity. The method of the present invention, which includes the use of metallic and precious metal catalysts, surprisingly yields 0°C haze-free heavy base oil in a higher yield compared to conventional base oil manufacturing methods.

[0012] DAO feedstock

[0013] The DAO feed is obtained by deasphalting residual hydrocarbon oil, preferably an atmospheric or vacuum residue fraction. The deasphalting process is carried out in any conventional manner well known in the art and known to those skilled in the art. The boiling point range of the DAO feed is about 300°C to about 1000°C and contains at least 50% by weight of hydrocarbons having a boiling point greater than 450°C. Preferably, the DAO feed contains more than 65% by weight and at least 50% by weight of hydrocarbons boiling greater than 450°C.

[0014] The DAO feed used during the present embodiment is pure DAO, or a blend of DAO and vacuum gas oil (VGO) in a ratio of about 6:1 to about 1:6. In another embodiment of the present invention, the DAO feed is a blend of two or more combinations of DAO, VGO, or hydrowax. Hydrowax is a paraffin fraction having a boiling point typically in the range of 280°C to 900°C, as described below, and is obtained after distillation of the hydrocracking product in the present embodiment.

[0015] The DAO feed contains nitrogen, sulfur, and aromatic compounds with a metal content (nickel (Ni) + vanadium (V)) in the range of about 2 to about 250 ppm or more. The nitrogen content is at least 400 ppm based on the total weight of the DAO feed relative to the residue. The sulfur content is at least 0.5 wt% based on the total weight of the DAO feed relative to the residue. The aromatic content of the DAO feed is in the range of at least 20 wt% to 90 wt%, more specifically at least 30 wt% to 70 wt%, and may include mono-aromatic, di-aromatic, and / or polycyclic aromatic content.

[0016] The DAO feedstock also contains a wax content in the range of up to 40 weight percent. Therefore, using DAO as a feedstock often produces a base oil having a haze precursor and a level and tendency for haze formation that is often unacceptable. Accordingly, the DAO feedstock described herein undergoes, among other process steps, hydrogenation, hydrocracking, catalytic dewaxing, and hydrofinishing steps in the presence of metal-based and precious metal-based catalysts to produce the haze-free heavy base oil of the present invention at 0°C.

[0017] Hydrogenation treatment

[0018] The DAO feed is provided in step (a) from, for example, a storage tank, a separator, or any known type of containment vessel. During the hydrogenation of step (b), a portion of the DAO feed is contacted with hydrogen in the presence of a hydrogenation catalyst system within a reactor to produce a hydrogenated product. Preferably, the hydrogenated product is a heavy feed having an initial boiling point greater than about 300°C and a final boiling point less than about 700°C. It is also preferable that at least 90 weight percent of the hydrogenated product has a boiling temperature greater than 570°C, and at least 95 weight percent of the hydrogenated product has a boiling temperature greater than 595°C. Upon completion of the hydrogenation step (b), the hydrogenated product comprises a reduced nitrogen content in the range of about 0.1 to about 30 ppm and a reduced sulfur content in the range of 10 to 200 ppm.

[0019] The hydrotreatment catalyst system comprises a combination of suitable catalysts for the reduction and / or removal of metals, nitrogen, sulfur, and aromatic substances, among other contaminants, from the DAO feed. The hydrotreatment catalyst system may be configured in any suitable configuration within a reactor. In a preferred embodiment, the hydrotreatment catalyst system comprises at least one hydrodemetallization catalyst and at least one hydrotreatment catalyst. More preferably, the DAO feed is initially exposed to at least one hydrodemetallization catalyst for the metal uptake of nickel (Ni) and vanadium (V) before the DAO feed is exposed to the hydrotreatment catalyst. Pre-exposure to the hydrodemetallization catalyst may reduce or minimize the deactivation of the hydrotreatment catalyst and / or other subsequent catalysts used during the remaining process steps.

[0020] A commercially available bimodal hydrodemetallic catalyst comprising a metal hydride component on a porous support (e.g., silica-alumina or alumina), suitably a group IVB or VIII metal (e.g., nickel-molybdenum, cobalt-molybdenum), is used to provide a total absorption of at least 30 wt% of Ni-V metal concentration in the DAO feed. After metal absorption, the DAO feed is exposed to at least one suitable hydrogenation catalyst.

[0021] Preferably, the hydrogenation 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 (these are incorporated herein by reference). The support material of the hydrogenation catalyst comprises any suitable inorganic oxide material typically used to carry the catalytically active metal component. Examples of possible inorganic oxide materials include alumina, silica, silica-alumina, magnesia, zirconia, boria, titania, and any mixture of two or more of these inorganic oxides. Preferred inorganic oxides for use in forming the support material are alumina, silica, silica-alumina, and mixtures thereof. However, the most preferred is alumina.

[0022] 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 preferred metal component. For Group VI metals, the metal salt comprises a Group VI metal oxide or sulfide. Metal salts of Group VI metals comprising ammonium heptamolybdate and ammonium dimolybdate are preferred. For Group IX and X metals, the metal salt comprises Group IX or X metal acetates, formattes, citrates, oxides, hydroxides, carbonates, nitrates, sulfates, and two or more of these. A preferred metal salt is a metal nitrate, e.g., nickel or cobalt nitrate, or both.

[0023] The weight percentage of catalytically active metal compounds incorporated into the support material varies depending on the application. Group VI metals (preferably molybdenum) are in the range of 5 to 50 weight%, preferably 8 to 40 weight%, and most preferably 12 to 30 weight% in the support material. Group IX and X metals (preferably nickel) are in the range of 0.5 to 20 weight%, preferably 1 to 15 weight%, and most preferably 2 to 12 weight% in the support material. The aforementioned weight percentages for the metals are based on the dry support material and the metals as elements, regardless of the actual form of the metals.

[0024] 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, and thus is a nitrogen atom to which up to three individual hydrogen atoms or one, two, or three atomic groups are bonded. Examples of preferred amine components are molecules selected from the group of compounds consisting of ether amine compounds, alkyl or alkenyl amine compounds, or amine oxide compounds.

[0025] The non-amine-containing polar additive of the hydrogenation catalyst comprises the polar additive compound described in U.S. Patent Publication No. US 2010 / 0236988, but excludes polar additive compounds that are heterocompounds having an amino functional group or a sulfur atom.

[0026] The relative weight ratio of the non-amine-containing polar additive to the amine compound incorporated into the metal-loaded support material is preferably in the upward range of 10:1 (10 parts by weight of non-amine-containing polar additive to 1 part by weight of some amine compound), for example, from 0:01 to 10:1. More typically, the weight ratio of the non-amine-containing 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 0.2:1 to 7:1, and most preferably 0.25:1 to 6:1.

[0027] A combination of an amine component and a polar additive containing a non-amine component within a metal-loaded support material provides a hydrogenation catalyst having enhanced catalytic properties compared to a typical composition comprising a support material loaded with an active metal precursor and having either the amine component alone or the polar additive containing a non-amine component alone. In order to obtain the beneficial effect of combining the amine component and the polar additive containing a non-amine component, the relative ratio of these two components incorporated into the support material must be within the aforementioned range.

[0028] The conditions for the hydrogenation treatment carried out in step (b) often depend on the desired conversion level, the type of catalyst used, and the level of contaminants in the DAO feed, among other factors. A suitable reaction temperature is in the range of 250 to 480°C, preferably 280 to 450°C, and more preferably 350 to 420°C. A suitable reaction pressure is in the range of 30 to 250 bar. Preferably, the reaction pressure is in the range of 110 to 180 bar, and more preferably 120 to 170 bar. The liquid hourly space velocity (LHSV) is suitably 0.2 to 10 hr -1 Range, preferably 0.2 to 2.0 hr -1 Range, more preferably 0.2 to 1.0 hr -1 It is a range.

[0029] Hydrocracking

[0030] The hydrogenated product of step (b) is contacted with hydrogen in step (c) in the presence of a hydrocracking catalyst system within a reactor to produce a hydrocracking product. To maintain heaviness, at least 15% to about 20% of the long-chain hydrocarbon molecules of the hydrogenated product that boil at 380°C or higher are converted into components that boil at less than 380°C during hydrocracking. The hydrocracking process of the present invention is well known in the art and comprises combining catalytic cracking and hydrogenation steps to decompose long-chain hydrocarbon molecules and haze precursors into simpler or short-chain molecules.

[0031] The reactor of the present invention is a suitable configuration as known to those skilled in the art and is defined by one or more reactor regions comprising one or more hydrocracking catalyst beds. More specifically, the reactor comprises a combination of a hydrogenation and a hydrocracking catalyst configured in a configuration suitable for multi-stage processing, and more preferably comprises at least three stages of processing including a first hydrogenation stage, a second hydrocracking stage, and a third hydrogenation stage. As will be understood by those skilled in the art, the multi-stage process is not limited to the configuration described herein, but may include additional or fewer stages to achieve the desired results.

[0032] Steps 1 and 3 are hydrogenation steps for reducing and / or removing residual nitrogen, sulfur, and unsaturated compounds from a product hydrogenated in the presence of a hydrogenation catalyst. The hydrogenation catalyst used is as described above in relation to step (b), which comprises a support material loaded with a catalytically active metal compound, an amine compound, and a non-amine-containing polar additive.

[0033] The hydrocracking of the hydrogenated product takes place in the second step in the presence of a hydrocracking catalyst as disclosed in U.S. Patent No. 9,199,228, incorporated herein by reference. The hydrocracking catalyst comprises a porous carrier 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 that implements a strong decomposition function.

[0034] The porous carrier of the hydrocracking catalyst comprises an amorphous binder and zeolite Y. The amorphous binder comprises any refractory inorganic oxide or a mixture of oxides. Generally, this is alumina, silica, silica-alumina, or a mixture of two or more of these. However, it is also possible to use zirconia, clay, aluminum phosphate, magnesia, titania, silica-zirconia, and silica-boria. The most preferred amorphous binder is silica-alumina. The amorphous silica-alumina preferably contains silica in an amount ranging from 25 wt% to 95 wt% when calculated based on the total weight of the carrier. More preferably, the amount of silica in the carrier is greater than 35 wt%, most preferably at least 40 wt%. A suitable amorphous silica-alumina product for use in manufacturing the porous carrier of the present invention comprises 45 wt% silica and 55 wt% alumina and is commercially available.

[0035] A preferred zeolite Y material is a zeolite Y having a silica-to-alumina ratio (SAR) greater than 10, particularly a unit cell size (a) less than 2.440 nm (24.40 Angstroms), particularly less than 2.435 nm (24.35 Angstroms). O It includes ultra-stable zeolite Y (USY) or very ultra-stable zeolite Y (VUSY) having a SAR greater than 10, particularly greater than 10 and less than or equal to 100. As used herein, the term SAR refers to the molar ratio of silica and alumina contained in the zeolite framework.

[0036] Suitable zeolite Y materials are known and are described, for example, in EP247678, EP247679, and WO2004 / 047988. The preferred VUSY zeolite of EP247678 or EP247679 has a unit cell size of less than 2.445 nm (24.45 angstroms) or 2.435 nm (24.35 angstroms), a moisture adsorption capacity of at least 8 wt% of the zeolite (at 25°C and p / p of 0.2). O It is characterized by a value), and a pore volume of at least 0.25 ml / g (where 10% to 60% of the total pore volume consists of pores having a diameter of at least 8 nm). Most preferred is a zeolite Y material with a low unit cell size and high surface area as described in WO2004 / 047988. Such materials have a SAR greater than 12, a unit cell size in the range of 24.10 to 24.40 Å, and at least 850 m² when measured by the BET method and ATSM D 4365-95. 2 It can be described as zeolite Y having a surface area of ​​ / g and nitrogen adsorption at a p / po value of 0.03.

[0037] While USY and VUSY zeolites are preferred for use in the present invention, other forms of Y zeolite, such as superhydrophobic Y zeolites, are also suitable for use.

[0038] In another embodiment, the porous carrier of the present invention may comprise an additional zeolite in addition to the aforementioned zeolite Y. Preferably, the additional zeolite is selected from zeolite beta, zeolite ZSM-5, or zeolite Y having a unit cell size and / or SAR different from that described above. The additional zeolite is preferably zeolite beta. The additional zeolite may be present in an amount of up to 20 weight% based on the total carrier weight, but preferably, the additional zeolite is present in an amount ranging from 0.5 weight% to 10 weight%.

[0039] The total amount of zeolite in the porous carrier is in the range of 2% to 70% by weight based on the total carrier weight, and the amount of amorphous binder is in the range of 8% to 30% by weight. Preferably, the total amount of zeolite in the porous carrier is in the range of 5% to 50% by weight, preferably 10% to 50% by weight based on the total carrier weight.

[0040] The hydrogenation component of the hydrocracking catalyst consists of Group VIB metals, preferably molybdenum and / or tungsten, and Group VIII metals, preferably cobalt, nickel, iridium, platinum and / or palladium, their oxides and sulfides. The hydrocracking catalyst will preferably contain at least two hydrogenation components, more specifically molybdenum and / or tungsten in combination 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 form of sulfides. The hydrocracking catalyst according to the present invention may contain up to 50 parts by weight of hydrogenation components, calculated as metals per 100 parts by weight (dry weight) of the total catalyst composition. For example, the hydrocracking catalyst may contain 2 to 40, more preferably 5 to 30, particularly 10 to 20 parts by weight of Group VIB metal(s) and / or 0.05 to 10, preferably 0.5 to 8, more preferably 1 to 6 parts by weight of Group VIB and Group VIII metal(s), calculated as metals per 100 parts by weight (dry weight) of the total catalyst composition.

[0041] The hydrocracking catalyst used in the present invention provides improved contaminant removal properties along with improved activity and selectivity, wherein 50% of the total pore volume of the hydrocracking catalyst is contained in pores having a diameter in the range of 4 to 50 nm. When measured by exchange with perdehydrogenated benzene, the acidity of the hydrocracking catalyst is 20 micromol / gram or less, and thus is lower than that of most known catalysts. The acidity is preferably up to 15, preferably up to 12, more preferably up to 10, and most preferably up to 8 micromol / gram. Although reduced acidity typically results in reduced hydrocracking activity, the hydrocracking catalyst of the present disclosure surprisingly provides increased gas oil selectivity at the same activity.

[0042] The hydrocracking process conditions described herein 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 embodiments, typical hydrocracking conditions are a reaction temperature in the range of 250 to 500°C, suitably 350 to 475°C, a reaction pressure in the range of 35 to 250 bar, suitably 100 to 200 bar, and 0.2 to 10 hr -1 , preferably 0.5 to 1.5 hr -1 It includes a weight hourly space velocity (WHSV) in the range. Hydrocracking process conditions also include a weighted average bed temperature (WABT) in the range of 350 to 420°C and a gas-to-oil ratio in the range of 500 NI / kg to 1500 NI / kg.

[0043] The hydrocracking reaction conditions are set to provide the desired conversion of a hydrogenated product with a boiling point of 380°C or higher into a low-boiling-point product (i.e., less than 380°C). Typically, the target conversion is at least 50%. It is desirable for the conversion of the hydrogenated product to exceed 60%, and most preferably, the conversion to exceed 75%.

[0044] Distillation System I

[0045] The hydrocracking product generated in step (c) may first pass through a gas-liquid separator before flowing to the distillation unit in step (d). The gas-liquid separator separates the hydrocracking product into a gaseous phase and a liquid phase under process conditions comprising a temperature in the range of about 100°C to about 350°C, more suitably about 130°C to about 240°C, and a pressure in the range of about 1 bar to about 50 bar, more suitably 1.5 bar to about 10 bar. The gaseous phase of the hydrocracking product may contain contaminants such as hydrogen sulfide (H2S) and ammonia (NH3), which are discharged from the gas-liquid separator as contaminated hydrogen-containing gas. In a preferred embodiment, at least 50% of the NH3 and H2S present in the hydrocracking product entering the gas-liquid separator are removed. Preferably, at least 80%, more preferably at least 90%, and most preferably at least 95% of the NH3 and H2S present in the hydrocracking product are removed. In addition, other impurities and contaminants such as methane (CH4), ethane (C2H6), liquefied petroleum gas (LPG), naphtha, and gas oil can be removed along with NH3 and H2S in step (d).

[0046] The separated liquid phase of the hydrocracking product flows into any suitable distillation unit, preferably a vacuum distillation unit or a vacuum tower, to be separated into fractions, for example, a lighter hydrocracking product and a heavy oil stream. The lighter hydrocracking product may include light and medium distillates having low boiling point temperatures in the range of 140 to 410°C. The light and medium distillates may include naphtha containing hydrocarbons boiling above about 100°C and below about 130°C, kerosene containing hydrocarbons boiling above about 130°C and below about 290°C, and diesel containing hydrocarbons boiling above about 290°C and below about 380°C.

[0047] Preferably, the heavy oil stream contains hydrogenated / hydrocracking DAO, i.e., hydrowax. Hydrowax is a suitable feedstock used in dewaxing or other hydrogenation techniques performed during the production of heavy base oil. The hydrowax fractionated and recovered in step (d) is a liquid product having a dynamic viscosity in the range of 4.0 to 20 cSt, a viscosity index of at least 120, a nitrogen content in the range of at least 0.01 to 20 ppm, a sulfur content in the range of at least 0.05 to 100 ppm, and a boiling point in the range of about 330°C to about 700°C.

[0048] In other embodiments, different and / or additional distillation and separation systems including an atmospheric distillation unit, a stripper, a fractionator, or a flash separator may be implemented based on the desired level of separation and process conditions, among other factors.

[0049] Catalytic Dewaxing / Hydrofinishing

[0050] The hydrowax recovered in step (d) is used as a feedstock during catalytic dewaxing to further produce the base oil product of the present invention. However, the recovered hydrowax may still contain wax compounds (e.g., haze precursors, normal paraffins, isoparaffins, etc.), aromatics, and other contaminants. When hydrowax containing these wax compounds and aromatics is used as a feedstock, it often produces a base oil product that has a high pour point and cloud point and a visual hazy appearance. Such a base oil product is not suitable for use and storage under low temperature conditions due to the formation of solid wax crystals formed internally.

[0051] In an embodiment, the hydrowax is catalytically dewaxed in the presence of a unique mixture of noble metal catalysts to reduce and / or remove any residual wax compounds from the hydrowax during the catalytic dewaxing of step (e). The mixture of noble metal catalysts described herein selectively removes the wax compounds of the hydrowax and / or converts them into a dewaxed product having reduced pour point and cloud point.

[0052] In step (e), the hydrowax is contacted with hydrogen in the presence of a precious metal-based catalyst composition contained in a reactor, for example, a hydrofinishing / isomerizing dewaxing reactor. The precious metal-based catalyst composition includes both a dewaxing catalyst and a hydrofinishing catalyst for removing residual haze precursors, other wax compounds, and aromatics.

[0053] Preferably, the dewaxing catalyst comprises a graded mixture of precious metal isomer dewaxing catalysts (“graded mixture”), which consists of 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 properties, and thus the description provided herein describes both catalysts. Modification of the catalyst is a process that mitigates the harmful effects of catalyst contamination (e.g., oxygen, water vapor, metals, etc.) without a substantial reduction in catalytic activity or selectivity. The modification method involves bringing the catalyst and / or catalyst surface into contact with contaminants so that the contaminants are adsorbed by the catalyst and subsequently released from the catalyst. Thus, unlike modified ZSM-12, ZSM-12 does not undergo a modification process.

[0054] As described herein, a graded mixture is defined as comprising a concentration gradient through the catalyst bed(s), i.e., a non-uniform concentration of each catalyst or a gradual difference in concentration. The phrase “through the catalyst bed(s)” is defined as comprising movement from the inlet to the outlet of the catalyst bed. The concentration gradient of the embodiments may be achieved in a single catalyst bed, separate catalyst beds, separate reactors, or multiple reactors.

[0055] As a first example, within a single catalyst bed, the concentration of ZSM-12 decreases and the concentrations of modified ZSM-12 and EU-2 and / or ZSM-48 increase in a linear or non-linear manner through the 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 through the catalyst bed from the inlet to the outlet. Furthermore, the concentrations of modified ZSM-12 and EU-2 and / or ZSM-48 are highest at the outlet or outlet region of the catalyst bed, and thus the concentrations of modified ZSM-12 and EU-2 and / or ZSM-48 increase linearly or non-linearly through the catalyst bed from the inlet to the outlet. For example, in a downward flow reactor, the inlet will be in the upper region of the catalyst bed that first comes into contact with the hydrowax, and the outlet will be in the lower region or bottom of the catalyst bed.

[0056] As a second example, in a separate catalyst bed, in a separate reactor or multiple reactors, when moving from one catalyst bed to the next catalyst bed(s) or reactor(s), the concentration of ZSM-12 decreases in a non-linear manner and the concentrations of modified ZSM-12 and EU-2 and / or ZSM-48 increase.

[0057] As a third example, the catalyst bed(s) may comprise two or more separate regions in a stacked configuration. Each region of the catalyst bed comprises a mixture of ZSM-12, modified ZSM-12, and EU-2 and / or ZSM-48 such that the entire region taken together defines a gradient in which the concentration of ZSM-12 decreases and the concentration of modified ZSM-12 and EU-2 and / or ZSM-48 increases in a stepwise, non-linear manner from one region to the next through the catalyst bed.

[0058] The preceding examples are merely a few of the various catalyst configurations found within the catalyst bed(s) and should not be interpreted or used to limit the scope of the invention. For example, those skilled in the art may select the configuration such that the concentration of modified ZSM-12 is highest at the inlet and the concentrations of ZSM-12 and EU-2 and / or ZSM-48 are highest at the outlet. The configuration selected for the catalyst may depend on various characteristics related to the process, such as the characteristics of the DAO feed, hydrowax, and the linear or non-linear concentration gradient required to produce a haze-free heavy base oil at 0°C, among other considerations.

[0059] Several gradient mixtures can be prepared with various ratios of ZSM-12 to modified ZSM-12 to EU-2 and / or ZSM-48. Then, the selected graded mixtures are loaded into catalyst bed(s) to achieve the desired concentration gradients for ZSM-12, modified ZSM-12, and EU-2 and / or ZSM-48 catalysts, respectively. Surprisingly, it was found that a higher base oil yield is obtained using the graded mixtures compared to using the non-gradient mixture (i.e., selected catalyst at a constant concentration) through the catalyst bed(s).

[0060] The SAR of both ZSM-12 and the modified ZSM-12 zeolite-based catalyst is sufficiently high to provide high yields of heavy lubricating base oils while exhibiting exemplary catalytic properties of high activity. In the embodiments, ZSM-12 and the 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 for the SAR of ZSM-12 and the modified ZSM-12 is preferably up to 250:1, more specifically, the upper limit is 200:1, more preferably less than 150:1, particularly less than 110:1. If the SAR of the synthesized ZSM-12 is too low, it may be further dealuminated using methods known in the art to provide dealuminated ZSM-12 having a desired SAR.

[0061] The content of ZSM-12 and modified ZSM-12 must be at least 10% by weight and no more than 70% by weight of the total weight of the graded mixture.

[0062] The binder content of ZSM-12 and modified ZSM-12 may be in the range of 30% by weight or more and 90% by weight or less of the total weight of the graded mixture. It is preferable that the binder content of ZSM-12 and modified ZSM-12 be up to 60% by weight of the graded mixture, more preferably up to 50% by weight, and even more particularly up to 40% by weight. It is even more preferable that the binder content of ZSM-12 and modified ZSM-12 be at least 15% by weight of the total weight of the graded mixture, more preferably at least 20% by weight. Furthermore, it is preferable that both ZSM-12 and modified ZSM-12 do not contain any additional zeolite.

[0063] The EU-2 and / or ZSM-48 of the graded mixture may contain a heat-resistant oxide binder that is essentially alumina-free. The SAR of the EU-2 and / or ZSM-48 is preferably at least 60, more preferably at least 70, more specifically at least 80, most preferably at least 90. The SAR of the EU-2 and / or ZSM-48 is preferably up to 300, more specifically up to 250, more specifically up to 200, most specifically up to 150.

[0064] EU-2 and / or ZSM-48 preferably comprises a graded mixture of up to 70 weight%, more specifically up to 65 weight%, even more specifically up to 60 weight%, and most preferably up to 55 weight%. Additionally, the amount of EU-2 / ZSM-48 is preferably at least 15 weight%, more specifically at least 20 weight%, more specifically at least 25 weight%, and most specifically at least 30 weight%.

[0065] Optionally, additional zeolite may be present in EU-2 and / or ZSM-48 in an amount of up to 50 weight percent based on the total amount of EU-2 and / or ZSM-48 present in the total weight of the graded mixture.

[0066] The binder content of EU-2 and / or ZSM-48 may be in the range of 30% by weight or more and 85% by weight or less of the total weight of the graded mixture. Reference to binders in the present invention includes heat-resistant oxide binders. Examples of heat-resistant oxide binder materials are alumina, silica, zirconia, titanium dioxide, germanium dioxide, boria, and mixtures of two or more (e.g., silica-zirconia and silica-titania). Preferred binders are titania, zirconia, and / or silica, wherein silica is the preferred binder of the graded mixture.

[0067] In the embodiments, the precious metal components of ZSM-12, modified ZSM-12, and EU-2 and / or ZSM-48 are preferably selected from the group of precious metals consisting of palladium and platinum. However, the preferred precious metal is platinum.

[0068] The precious metal content for each catalyst in the graded mixture may be in the range of about 3 weight percent or more based on the precious metal as an element, regardless of the actual form and the total weight of the graded mixture. The concentration of the precious metal component present in the graded mixture is preferably in the range of 0.1 weight percent to 3 weight percent. More preferably, the concentration of the precious metal component is 0.2 to 2 weight percent, and most preferably 0.3 to 1 weight percent.

[0069] The graded mixture of the present invention is highly suitable for dewaxing hydrocarbon feedstocks such as hydrowax to increase the removal of wax crystals and, consequently, wax compounds that form visual haze in base oil products. Accordingly, the system can be used in any conventional lineup that includes a section for dewaxing hydrocarbon feedstocks such as hydrowax.

[0070] As described above, the noble metal-based catalyst composition of a hydrofinishing / isomerizing dewaxing reactor may include a hydrofinishing catalyst to remove and / or reduce the aromatic content. Preferably, the hydrofinishing catalyst is a noble metal aromatic hydrogenation catalyst comprising at least one noble metal component incorporated on a support substrate made of zirconia and other inorganic oxide components. Preferably, the noble metal aromatic hydrogenation catalyst comprises 0.01 to 5 weight% of a noble metal selected from platinum, palladium, and combinations thereof, 1 to 30 weight% of zirconia, and 60 to 99 weight% of an inorganic oxide selected from the group consisting of silica, alumina, and silica-alumina. A commercially available hydrofinishing catalyst is disclosed in U.S. Patent No. 7,737,074, which is incorporated herein by reference.

[0071] Zirconium and inorganic oxides constituted the support substrate. Specifically, zirconia and inorganic oxides were co-mulled to form a mixture that later forms aggregated particles, which are then dried and calcined to form further calcined particles. The calcined particles are suitable for use as a support substrate for noble metal aromatic hydrogenation catalysts.

[0072] The zirconium compound used as a support carrier may be selected from the group consisting of zirconium oxides, nitrates, silicates, carbonates, acetates, chlorides, hydroxides, and hydrates. Specific examples of possible suitable zirconium compounds that are powdered together with inorganic oxides 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)); ammonium zirconyl acetate ((NH4)2rO(CHO)); zirconyl phosphate (ZrO(HPO)); zirconium tetrachloride (ZrOl); It includes zirconium silicate (ZrSiO); and zirconium oxide (ZrO). Preferred zirconium compounds include ammonium zirconyl carbonate and zirconyl acetate.

[0073] The inorganic oxide material used as a support carrier may be selected from the group of inorganic oxides consisting of silica, alumina, silica-alumina, and any combination of two or more of these. The preferred inorganic material combined with the zirconium compound is selected from silica or alumina, or a combination of both.

[0074] When the support carrier contains both silica and alumina in relative amounts such that the molar ratio of SAR is in the range of 1:10 to 10:1, the support carrier contains zirconium as an element in an amount ranging from 0.5 to 20 weight%, preferably 1 to 15 weight%, most preferably 2 to 10 weight% (weight% is calculated based on the total weight of the support carrier and assuming zirconium is a metal).

[0075] Where the support carrier has a SAR greater than 10:1, including cases where the support carrier is substantially devoid of alumina or contains only silica combined with zirconia, the support carrier must have a zirconium content as an element in an amount ranging from 3 to 30 weight%, preferably from 5 to 25 weight%, most preferably from 7 to 20 weight% (weight% is calculated based on the total weight of the support carrier and assuming zirconium is a metal).

[0076] The surface area of ​​precious metal aromatic hydrogenation catalysts is generally 200 to 500 m² 2 / gm, preferably 250 to 450 m 2 / gm, more preferably 300 to 400 m 2 The range is / gm. The pore volume of the noble metal aromatic hydrogenation catalyst determined using the standard mercury porosity measurement method is generally in the range of 0.7 to 1.3 ml / gm, and the median pore diameter of the noble metal aromatic hydrogenation catalyst is in the range of 50 Å to 250 Å.

[0077] A preferred precious metal aromatic hydrogenation catalyst comprises both a platinum component and a palladium precious metal component in a weight ratio of elemental palladium to platinum ranging from 1:10 to 10:1, preferably from 1:2 to 5:1, and most preferably from 1:1 to 3:1. Accordingly, the precious metal incorporated into the support substrate must provide a catalyst composition having a precious metal content ranging from 0.01 to 5 weight% for each precious metal (weight% is based on the total weight of the final catalyst composition and is calculated as an elemental metal). A preferred precious metal content for each precious metal component is in the range of 0.1 to 4 weight%, and most preferably from 0.2 to 3 weight%.

[0078] The precious metal-based catalyst composition of the hydrofinishing / isomerizing dewaxing reactor, comprising a graded mixture and a precious metal aromatic hydrogenation catalyst, can improve the performance and quality of the final product by removing haze precursors, other wax compounds, and aromatics while improving the yield during catalytic dewaxing. In particular, the dewaxed product produced in step (e) has a pour point preferably at least 40°C, more preferably at least 60°C, lower than the pour point of the DAO feed and hydrowax entering the hydrofinishing / isomerizing dewaxing reactor.

[0079] In a preferred embodiment, the graded mixture and the noble metal aromatic hydrogenation catalyst may be located in the same bed, but may be located in separate beds, in separate beds, or in multiple beds, or in the same reactor, in separate reactors, or in multiple reactors. Additionally, the noble metal aromatic hydrogenation catalyst may be loaded before or after the graded mixture is loaded into the hydrofinishing / isomerizing dewaxing reactor.

[0080] Catalytic dewaxing conditions are known in the art and typically include a reaction temperature in the range of 200 to 500°C, suitably 250 to 400°C, a reaction pressure in the range of 10 to 200 bar, suitably 15 to 100 bar, more suitably 15 to 65 bar, and 0.2 to 10 hr -1 , suitably 0.2 to 5 hr -1 , more appropriately 0.5 to 3 hr -1 It includes a weight hourly space velocity (WHSV) in the range. Additionally, the catalytic dewaxing conditions may include a weighted average bed temperature (WABT) in the range of 320 to 370°C and a gas-to-oil ratio in the range of 500 to 1500 NI / kg.

[0081] Hydrofinishing

[0082] The dewaxed product is hydrofinished in step (f) in the presence of a hydrofinishing catalyst to produce a hydrofinished product. The hydrofinishing catalyst is preferably a noble metal aromatic hydrogenation catalyst as described above in relation to the hydrofinishing catalyst used in step (e). The hydrofinishing process is well known in the art and involves removing mono-aromatic and polycyclic aromatic compounds, among other aromatic compounds, from the dewaxed product to ensure the stability of the final product, such as oxidation stability.

[0083] Generally, the hydrofinishing process involves a reaction temperature range of about 125 to 390°C, a reaction pressure range of about 70 to 200 bar, a weighted average bed temperature (WABT) range of 220 to 270°C, a gas-to-oil ratio range of 500 to 1500 NI / kg, and 0.3 to 3.0 hr -1It is carried out under conditions of a weight hourly space velocity (WHSV) of a range. If possible, the severity of the hydrofinishing reaction should be kept low, as increasing reaction conditions contribute to a gradually decreasing viscosity in haze-free heavy base oil compositions at 0°C, resulting in a low heavy oil yield.

[0084] Distillation System II

[0085] The hydrofinished product generated in step (f) passes to a distillation unit in step (g) and is fractionated by conventional methods such as vacuum distillation under atmospheric pressure or reduced pressure. Similar to the previous distillation system in step (d), the hydrofinished product is initially passed through a gas-liquid separator and then flows into a distillation unit in step (g) where it can be fractionated into a lighter product and a heavy oil stream.

[0086] Any suitable vacuum distillation unit or vacuum tower known to those skilled in the art may be used to distill and separate the hydrofinished product into fractions comprising a light distillation fuel product, an intermediate distillation fuel product, and a heavy base oil composition. The separated light distillation fuel product may have a boiling point of less than about 390°C and a viscosity in the range of 2 to 3 cSt at 100°C, and the separated intermediate distillation fuel product may have a boiling point in the range of 390 to 510°C and a viscosity in the range of 4.5 to 7.0 cSt at 100°C. The heavy base oil composition is a heavy base oil that is hazy at 0°C with improved low-temperature flow characteristics.

[0087] Recovery of Group II / III heavy base oils

[0088] In step (h), the fractionated heavy base oil that is hazy at 0°C is recovered. The combination of process steps in the presence of the aforementioned catalyst composition produces a heavy base oil that is hazy at 0°C, having reduced pour point and rolling point, low contaminant content, and increased viscosity index and dynamic viscosity. In particular, the heavy base oil that is hazy at 0°C is a Group II / III heavy base oil that appropriately contains sulfur in an amount of less than 5 ppm, preferably less than 1 ppmw, and nitrogen in an amount of less than 5 ppm, preferably less than 1 ppmw. The recovered heavy base oil composition that is hazy-free at 0°C comprises a dynamic viscosity in the range of 15 to 21 cSt at 100°C, a viscosity index in the range of 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 less than -12°C, a rolling point less than -18°C, a total aromatic content of 2 weight% or less, and a total saturated content of at least 98 weight%. More preferably, the recovered heavy base oil composition that is hazy-free at 0°C comprises a dynamic viscosity in the range of 19 to 20 cSt at 100°C, a viscosity index in the range of 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 less than -24°C, a rolling point less than -21°C, a total aromatic content of 1 weight% or less, and a total saturated content of at least 99 weight%.

[0089] As is known in the art, base oil products may contain a sufficient amount of haze precursors even after undergoing a hydrogenation step. In this case, wax crystals (e.g., solid hydrocarbon crystals) often form in the base oil when exposed to low temperatures and / or during storage, producing an undesirable haze appearance. The degree of wax formation characterizes low-temperature flow characteristics, such as the pour point and cloud point, and indicates the usability of the base oil for specific applications at low temperatures. The pour point is the temperature at which the oil begins to flow, and the cloud point refers to the temperature at which the oil begins to become cloudy due to the formation of wax crystals.

[0090] However, the haze-free heavy base oil at 0°C and its manufacturing method support reduced wax and haze formation due to lower pour and rolling points, in addition to overall improved performance compared to conventional heavy base oil products. As an indicator of improved low-temperature flow characteristics, a wax cloudiness test is performed on the haze-free heavy base oil at 0°C. This test is a pass / fail determination used to determine whether the recovered haze-free heavy base oil maintains a haze-free appearance when stored at low temperatures without stirring (i.e., without disturbance) for an extended test period. In particular, the test is performed at a temperature of 0°C without disturbance or stirring, for example, without stirring, for a test period of at least 5 hours, preferably at least 7 hours. Surprisingly, it was found that the haze-free heavy base oil of the present invention at 0°C did not form any wax crystals when a wax turbidity test was performed, and thus maintained a haze-free appearance when stored undisturbed for an extended period at 0°C, for example, 5 hours, preferably 7 hours.

[0091] Accordingly, the present embodiment provides an improvement over known base oils and manufacturing methods by applying a DAO feed in a series of steps in the presence of a unique catalyst composition to produce a haze-free heavy base oil at 0°C having reduced pour point and rolling point. As indicated by its ability to pass the wax turbidity test, the haze-free heavy base oil at 0°C does not form solid wax compounds when exposed to low temperatures. This improvement in low-temperature flow characteristics exhibited by the haze-free heavy base oil at 0°C of the present invention makes it a desirable option for use during heavy load and low-temperature applications compared to conventional base oils.

[0092] In addition to improved low-temperature flow characteristics, the method of the present invention, performed in the presence of a catalyst composition, further provides a heavy base oil that is hazy at 0°C with low contaminants and aromatic content, thereby providing overall product stability. The heavy base oil that is hazy at 0°C according to the present invention possesses additional advantages over conventional heavy base oils. Surprisingly, it has been found that the embodiments of the method produce a high proportion of heavy base oil that is hazy at 0°C compared to light base oils, providing a total product yield of at least 99.8 weight%. Additionally, the heavy base oil that is hazy at 0°C possesses a Saybolt color of +20 or higher, preferably +24 or higher, and more preferably +26 or higher. The Saybolt color referred to herein refers to a value measured according to JIS K 2580 “Petroleum Products—Color Test Methods—Saybolt Color Test Methods” and includes the purpose of removing substances that impede oxidation stability.

[0093] The drawing illustrates an exemplary embodiment of a flow process for producing haze-free heavy base oil from a deasphalted (DAO) feed at 0°C. A pure DAO feed flows through line (102) to a pretreatment unit (104). Optionally, the feed may contain a blend of DAO, vacuum gas oil (VGO), and hydrowax fractions in any combination thereof. The pretreatment unit (104) may include at least two commercially available catalyst beds containing a hydrodemetallic catalyst and a hydrotreatment catalyst to remove nitrogen, sulfur, and aromatic compounds, among other impurities. The hydrotreated product is withdrawn from the pretreatment unit (104) through line (106) and flows to a hydrocracker unit (108). The hydrotreated product is subjected to suitable hydrocracking conditions to decompose at least some of the heavy hydrocarbons and haze precursors in the DAO feed into low-boiling point hydrocarbons to produce a hydrocracking product. The hydrocracker unit (108) may contain a hydrogenation treatment and hydrocracker catalyst, for example, a metal-based hydrogenation denitrification catalyst, a hydrogenation desulfurization catalyst, and a hydrocracker catalyst.

[0094] The hydrocracking product is passed from the hydrocracking unit (108) through line (110) to the first vacuum distillation unit (112) to be distilled and separated into various fractions. The residual product, including the light distillate and the intermediate distillate, is collected individually through line (114) and line (116), respectively, and removed from the first vacuum distillation unit (112). The residual product may contain at least one of ammonia (NH3), hydrogen sulfide (H2S), methane (CH4), ethane (C2H6), liquefied petroleum gas (LPG), naphtha, and gas oil, among other contaminants.

[0095] The hydrowax, which is a heavy oil stream, is collected separately via line (120) and flows to a hydrofinishing / isomerizing dewaxing unit (122). In some embodiments, a portion of the hydrowax passing through line (118) may be recirculated to a hydrocracking unit (108) as a feedstock to increase the yield of an intermediate distillate containing kerosene and diesel products, such as ultra-low-sulfur diesel fuel. In other embodiments, a portion of the intermediate distillate passing through line (116) may be mixed with the hydrowax via line (120) and flow to a hydrofinishing / isomerizing dewaxing unit (122).

[0096] The hydrofinishing / isomerizing dewaxing unit (122) is filled with a precious metal-based catalyst system consisting of a graded mixture formulated to produce, for example, an aromatic hydrogenation catalyst and a heavy base stock oil having improved low-temperature flow characteristics. The dewaxed product is produced and flows from the hydrofinishing / isomerizing dewaxing unit (122) to a second hydrofinishing unit (126) via line (124). The second hydrofinishing unit is filled with a hydrofinishing catalyst, for example, an aromatic hydrogenation catalyst used in unit (122). The hydrofinishing product is passed through line (128) to a second vacuum distillation unit (130) and fractionated into various base oils according to desired characteristics, such as use and viscosity grade. In this embodiment, the hydrofinishing product is fractionated to provide a heavy base oil (132) that is haze-free at 0°C. Further fractions from the hydrofinished product include a light distillation fuel product (134) having a boiling point of less than 380°C and a viscosity of 2 to 3 cSt at 100°C, and an intermediate distillation fuel product (136) having a boiling point of 380°C to 600°C and a viscosity of 4.5 to 7.0 cSt at 100°C.

[0097] The following examples are intended to illustrate improved characteristics and capabilities as provided by embodiments of the present invention.

[0098] Example 1

[0099] Example 1 describes a DAO feed that is processed by the embodiment of the method to produce the base oil composition of the present invention. The composition of the DAO feed used in each experiment is shown in Table 1.

[0100]

[0101]

[0102] As described in Table 1, the DAO feedstock was subjected to a hydrogenation technology including hydrogenation and hydrocracking process steps during the experimental test. The DAO was initially hydrogenated on a hydrogenation catalyst system comprising at least one hydrodemetallic catalyst and at least one hydrogenation catalyst to produce a hydrogenated product. The hydrogenation catalyst included a support material loaded with a catalytically active metal compound, an amine compound, and a non-amine-containing polar additive.

[0103] Subsequently, the hydrogenated product was hydrocracking in the presence of a combination of a hydrogenation and hydrocracking catalyst configured for a multi-stage process. The hydrogenation catalyst was as described above. The hydrocracking catalyst included a porous carrier comprising an amorphous binder and zeolite Y. The porous carrier was further impregnated with a hydrogenation component, suitably a Group VIII (preferably cobalt, nickel, iridium, platinum and / or palladium) and / or a Group IVB (preferably molybdenum and / or tungsten) catalytically active metal.

[0104] After hydrogenation and hydrocracking, a hydrogenated product (i.e., hydrocracking product) was produced containing a pour point of +27°C, 1.4 ppm of nitrogen, and 10 ppm of sulfur. The operating conditions and main results of the hydrogenation step are shown in Table 2.

[0105]

[0106] Comparative Example 1

[0107] Comparative Example 1 provides the results of a comparative experimental test using the same DAO feedstock as provided in Table 1. The DAO feedstock was hydrogenated to a pour point of +51 and similar nitrogen and sulfur levels of <2 ppmw and <30 ppmw, respectively, to match the typical requirements for second-stage precious metal isomerization-dewaxing and hydrofinishing catalysts according to current practice. The hydrogenation catalysts included a highly active NiMo / Al2O3-type II hydrogenation catalyst and a decomposition bed of amorphous silica alumina catalyst. The operating conditions and key results of the hydrogenation step in Comparative Example 1 are shown in Table 3.

[0108]

[0109] A comparison of results between the present invention (Table 2) and current practice (Table 3) is provided in Table 4.

[0110]

[0111] When comparing the results provided in Table 2 of the present invention with the results of current practice in Table 3, the method of the present invention performed in the presence of hydrogenation treatment and a hydrocracking catalyst produces a hydrocracking product having improved low-temperature flow characteristics and reduced contaminant removal.

[0112] Example 2

[0113] The hydrogenated products of Table 2 were fractionated to recover hydrogenated / hydrocracking DAO, e.g., hydrowax. This Example 2 provides the results of experimental tests during the catalytic dewaxing of hydrowax with a precious metal-based catalyst composition to further remove wax compounds and aromatics during the production of the heavy base oil of the present invention. The precious metal-based catalyst composition comprises both a dewaxing catalyst and a hydrofinishing catalyst. The dewaxing catalyst contained a graded mixture of precious metal isomerization dewaxing catalysts. The hydrofinishing catalyst contained a precious metal aromatic hydrogenation catalyst.

[0114] After catalyst dewaxing, a catalyst-dewaxed product was produced having a pour point of -48°C and a cloud point of -21°C. The operating conditions and main results of the catalyst dewaxing step are shown in Table 5.

[0115]

[0116] Comparative Example 2

[0117] Comparative Example 2 provides the results of a comparative experimental test after removing contaminants and light products (ASTM D2887 IBP = 372°C) from the hydrogenated effluent listed in Table 3. The hydrogenated effluent was catalytically dewaxed in a Shell commercial dewaxing catalyst system specifically developed for the dewaxing of heavily hydrogenated feedstocks for the production of Base Oils II and III. The operating conditions and key results of the catalytic dewaxing step of Comparative Example 2 are shown in Table 6.

[0118]

[0119] A comparison of results between the present invention (Table 5) and current practice (Table 6) is provided in Table 7.

[0120]

[0121] When comparing the results provided in Table 5 of the present invention with the results of current practice in Table 6, the method of the present invention, performed in the presence of a precious metal-based catalyst composition containing a graded mixture of dewaxing catalysts, produced a catalytic dewaxing product having improved low-temperature flow characteristics, including a pour point of -48°C and a cloud point of -21°C. Conversely, during current practice, the product produced had a higher pour point of -27°C and a higher cloud point of +9°C.

[0122] Example 3

[0123] Example 3 provides the results of experimental tests during the hydrofinishing of the catalytic dewaxing product as described in Table 5. The catalytic dewaxing product is hydrofinished in the presence of a precious metal aromatic hydrogenation catalyst to remove mono-aromatic and polycyclic aromatic compounds, among other aromatic compounds, during the production of the heavy base oil of the present invention. After hydrofinishing, a hydrofinished product was produced having a pour point of -45°C and a cloud point of -18°C, along with reduced nitrogen and sulfur content of 1.0 ppmw and 3.5 ppmw, respectively. The operating conditions of the hydrofinishing step for producing the hydrofinished product and the main results are shown in Table 8.

[0124]

[0125] Comparative Example 3

[0126] Comparative Example 3 provides the results of a comparative experimental test of a dewaxed product in which a hydrofinishing step was performed using Criterion’s precious metal hydrofinishing catalyst (LN-5). The operating conditions and main results of the hydrofinishing step of Comparative Example 3 are shown in Table 9.

[0127]

[0128] A comparison of results between the present invention (Table 8) and current practice (Table 9) is provided in Table 10.

[0129]

[0130] When comparing the results provided in Table 8 of the present invention with the results of current practice in Table 9, the method of the present invention performed in the presence of metallic and precious metal catalysts exhibited improved low-temperature flow characteristics, including a pour point of -45°C and a rolling point of -18°C, as provided in Table 9. Conversely, during current practice, the base oil produced had a higher pour point of -12°C and a higher rolling point of +9°C compared to the haze-free heavy base oil of the present invention at 0°C. Additionally, the haze-free heavy base oil at 0°C passed the wax turbidity test, in contrast to the conventionally produced base oil that failed the test.

[0131] While the described method may allow for various modifications and alternative forms, the exemplary embodiments described above are presented merely as examples. It should be understood that the method of the present invention is not intended to be limited to the specific embodiments disclosed herein. Furthermore, references to “one embodiment,” “an embodiment,” or similar language throughout this specification mean that specific features, structures, or characteristics described in relation to the embodiment may be included in at least one embodiment of the present invention. Accordingly, phrases such as “one embodiment,” “an embodiment,” or similar language throughout this specification may all refer to the same embodiment, but are not necessarily so.

[0132] Although the invention has been described in relation to specific details, such details should not be construed as limitations on the scope of the invention, except for the scope included in the appended claims.

Claims

Claim 1 A method for preparing a base oil composition comprising: (a) providing a deasphalted oil (DAO) feedstock; (b) hydrogenating a portion of the DAO feedstock in the presence of a hydrogenation catalyst to produce a hydrogenated product; (c) hydrocracking the hydrogenated product in the presence of a hydrocracking catalyst to produce a hydrocracking product; (d) fractionating the hydrocracking product, wherein at least one fraction comprises a hydrowax; (e) catalytically dewaxing the hydrowax in the presence of a precious metal catalyst to produce a dewaxed product, wherein the precious metal catalyst comprises: i) a ZSM-12 zeolite-based catalyst; ii) a modified ZSM-12 zeolite-based catalyst; and iii) at least one of an EU-2 zeolite-based catalyst and a ZSM-48 zeolite-based catalyst; A method for preparing a base oil composition comprising: a step of comprising a graded mixture including; (f) a step of hydrofinishing the dewaxed product in the presence of a hydrofinishing catalyst to produce a hydrofinished product; (g) a step of fractionating the hydrofinished product, wherein at least one fraction comprises a base oil composition; wherein the base oil composition is a heavy base oil composition that is haze-free at 0°C, comprising (a) a dynamic viscosity in the range of 15 to 21 cSt at 100°C, (b) a viscosity index of at least 95, (c) a pour point of less than -12°C, and (d) a rolling point of less than -18°C, and (e) a total aromatic content of 2 wt% or less; wherein the heavy base oil that is haze-free at 0°C maintains a haze-free appearance when stored undisturbed at 0°C for a test period of at least 5 hours; and wherein the heavy base oil composition that is haze-free at 0°C is a Group II or III base oil. Claim 2 A method according to claim 1, wherein the base oil composition comprises a sulfur content of less than 5 ppm and a nitrogen content of less than 5 ppm. Claim 3 A method according to claim 1, wherein the base oil composition comprises a saturated content in the range of 98% to 99.9% by weight. Claim 4 The method of claim 1, wherein the DAO feed comprises 50 wt% or more of a hydrocarbon boiling above 450°C, 400 ppm or more of nitrogen, 0.5 wt% or more of sulfur, and a metal content of (nickel (Ni) + vanadium (V)) in the range of 2 to 250 ppm. Claim 5 A method according to claim 4, wherein the hydrogenated product comprises nitrogen in the range of 0.1 to 30 ppm, sulfur in the range of 10 to 200 ppm, and (Ni+V) metal in which at least 30% of the (Ni+V) metal content is absorbed by a hydrodemetallization catalyst. Claim 6 A method according to any one of claims 1 to 5, further comprising a hydrogenation treatment catalyst bed in step (c) to produce the hydrocracking product. Claim 7 A method according to any one of claims 1 to 5, wherein the hydrowax of step (d) comprises a dynamic viscosity of at least 4.0 cSt at 100°C, a viscosity index of at least 120, a nitrogen content of less than 20 ppm, and a sulfur content of less than 100 ppm. Claim 8 A method according to any one of claims 1 to 5, further comprising the step of removing a residual product from the hydrocracking product in step (d), wherein the residual product comprises at least one of ammonia (NH3), hydrogen sulfide (H2S), methane (CH4), ethane (C2H6), liquefied petroleum gas (LPG), naphtha, and gas oil. Claim 9 delete Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete Claim 21 delete Claim 22 delete Claim 23 delete Claim 24 delete Claim 25 delete Claim 26 delete Claim 27 delete Claim 28 delete Claim 29 delete Claim 30 delete Claim 31 delete

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