Mineral oil-based lubricating base oil with improved low-temperature performance, method for producing the same, and lubricating oil product containing the same

Abstract

The present disclosure provides a mineral oil-based lubricant base oil with improved low temperature performance, the lubricant base oil having a kinematic viscosity of 9.0 cSt (40°C) or less, a kinematic viscosity of 2.5 cSt (100°C) or less, and a pour point of -50°C or less.

Description

[Technical Field]

[0001] The present disclosure relates to a mineral oil-based lubricant base oil having improved low-temperature performance, a method for producing the same, and a lubricant product containing the same. More particularly, the present disclosure relates to a mineral oil-based lubricant base oil having improved low-temperature performance and an ultra-low viscosity produced from hydrocracked liquid gas oil (t-LGO), a method for producing the same, and a lubricant product containing the same. [Background technology]

[0002] Lubricant base oils are the raw materials used to make lubricant products, and generally, good lubricant base oils have a high viscosity index, excellent stability (oxidation, heat, UV, etc.), and low volatility. The American Petroleum Institute (API) classifies lubricant base oils according to their quality as shown in Table 1 below.

[0003] [Table 1]

[0004] Generally, among mineral oil-based lubricating base oils, lubricating base oils produced by solvent extraction mainly belong to Group I, lubricating base oils produced by hydrogenation reforming mainly belong to Group II, and lubricating base oils with high viscosity indexes produced by advanced hydrocracking reactions mainly belong to Group III.

[0005] Meanwhile, there is a need for lubricating oil products that can be used in extreme temperatures, such as in extremely cold or polar regions. To this end, additives such as pour point depressants and viscosity modifiers have been added to conventional lubricating base oils to improve the low-temperature properties of lubricating oil products. However, excessive amounts of these additives can impair the performance of the lubricating oil product itself, so there are limitations on their addition. Therefore, there is a need for lubricating base oils with improved low-temperature performance.

[0006] Such lubricating base oils are required to have low viscosity and low pour point. Suitable lubricating base oils include synthetic base oils such as polyalphaolefins (PAOs) and ester-based base oils. PAOs have excellent viscosity stability and low-temperature fluidity, while ester-based base oils also have excellent viscosity stability. However, PAOs and ester-based base oils have the disadvantage of being expensive.

[0007] Therefore, efforts have been made to produce mineral-based lubricant base oils that have comparable or superior low-temperature performance to synthetic base oils while being more cost-competitive than synthetic base oils. For example, one process for producing lubricant base oil feedstock in conjunction with conventional fuel oil hydrocracking (HC) processes uses unconverted oil (UCO) generated by hydrocracking vacuum gas oil produced in a vacuum distillation process. In this process, the fraction undergoes a hydrotreating process to remove impurities such as sulfur, nitrogen, oxygen, and metal components. A significant amount of the UCO is converted into light hydrocarbons through the hydrocracking process, which is the main reaction process. A series of fractional distillation processes separates the various cracked oils and gases, resulting in the light fraction being commercialized. In the above reaction, the reaction conversion rate per pass is generally designed to be about 40%, and since it is practically impossible to achieve a conversion rate per pass of 100%, unconverted oil (UCO) is always generated in the final fractional distillation step, a portion of which is extracted to the outside and used as a raw material for lubricating base oil, and the remainder is recycled to the hydrocracking step.

[0008] The prior patent, Korean Patent No. 10-1399207, relates to a method for producing a high-grade lubricant base oil feedstock using unconverted oil, and only discloses a method for producing a high-grade lubricant base oil from the unconverted oil by feeding a part of the unconverted oil to a second hydrocracking step and recycling it, but does not disclose the use of hydrocracked liquid gas oil as a feedstock for producing lubricant base oil.

[0009] In addition, the prior patent, Korean Patent No. 10-1679426, relates to a method for producing high-quality lubricant base oil using unconverted oil, and only discloses producing lubricant base oil using two or more types of unconverted oil, but does not disclose producing lubricant base oil using substances other than unconverted oil as feedstocks.

[0010] Therefore, as previously mentioned, there remains a need for new mineral oil-based lubricating base oils that are cost-competitive with synthetic base oils, yet have equivalent or better low temperature performance. Summary of the Invention [Problem to be solved by the invention]

[0011] Therefore, a first aspect of the present disclosure is to provide a mineral oil-based lubricating base oil with improved low-temperature performance that can replace the above-mentioned expensive synthetic base oils. A second aspect of the present disclosure provides a finished lubricant comprising the lubricant base oil of the first aspect. [Means for solving the problem]

[0012] To achieve the first aspect of the present disclosure, a mineral oil-based lubricating base oil with improved low temperature performance has a kinematic viscosity of 9.0 cSt (40°C) or less, a kinematic viscosity of 2.5 cSt (100°C) or less, and a pour point of -50°C or less.

[0013] According to one embodiment of the present disclosure, the lubricating base oil is derived from a feedstock comprising hydrocracked liquid gas oil, wherein the treated liquid gas oil has a 10% boiling point of 250°C or less and a 50% boiling point of 350°C or less in a simulated distillation test according to ASTM D2887.

[0014] According to one embodiment of the present disclosure, the treated liquid gas oil has a specific gravity of 0.81 to 0.87, a kinematic viscosity of 5.0 cSt (40°C) or less, a kinematic viscosity of 2.0 cSt (100°C) or less, a pour point of 5°C or less, and contains sulfur and nitrogen in amounts of 2.0 wt% or less each.

[0015] According to one embodiment of the present disclosure, the feedstock comprises 90% by weight or more of the treated liquid gas oil.

[0016] According to one embodiment of the present disclosure, the average carbon number of hydrocarbon molecules in the lubricating base oil is 14-25.

[0017] According to one embodiment of the present disclosure, the lubricating base oil contains hydrocarbons having 13 or fewer carbon atoms in an amount of 25 wt % or less based on the total lubricating base oil.

[0018] According to one embodiment of the present disclosure, the lubricating base oil comprises 10 to 50 wt % naphthenic hydrocarbons.

[0019] According to one embodiment of the present disclosure, the lubricating base oil has a viscosity of 0.3≦(C N +C A ) / C P ≦0.7, where C N is the weight percent of naphthenic hydrocarbons, and C A is the weight percent of aromatic hydrocarbons, and C P is the weight percent of paraffinic hydrocarbons.

[0020] According to one embodiment of the present disclosure, the lubricating base oil has a viscosity of 25%≦C N +C A ≦45%, where C N is the weight percent of naphthenic hydrocarbons, and C A is the weight percent of aromatic hydrocarbons.

[0021] According to one embodiment of the present disclosure, the lubricating base oil has a kinematic viscosity of 500 cSt (-40°C) or less.

[0022] According to one embodiment of the present disclosure, the lubricating base oil has a flash point of 110°C or higher, an evaporation loss at 150°C of 20% by weight or less, and a 5% distillation temperature of 200°C or higher in a simulated distillation test according to ASTM D2887.

[0023] A finished lubricant oil for achieving the second aspect of the present disclosure comprises 20 to 99 wt % of the lubricant base oil of the first aspect of the present disclosure and has a pour point of -40°C or less.

[0024] According to one embodiment of the present disclosure, the finished lubricant does not contain synthetic base oils.

[0025] According to one embodiment of the present disclosure, the finished lubricant does not contain polyalphaolefins (PAO) or ester-based base oils. [Effects of the Invention]

[0026] The lubricating base oils according to the present disclosure have lower viscosities and pour points than conventional low-viscosity lubricating base oils, and therefore exhibit improved low-temperature performance. These lubricating base oils can be used in ultra-low viscosity, high-performance lubricating oil products where low-temperature performance is important, or in lubricating oil products used in extremely low-temperature regions. Furthermore, by appropriately blending these lubricating base oils with conventional mineral oil-based lubricating base oils, lubricating oil products that meet the required performance can be produced.

[0027] Conventionally, when producing the above-mentioned lubricating oil products, expensive synthetic base oils such as PAO and ester-based base oils had to be used to satisfy the required performance. However, the lubricating base oils disclosed herein can be used to replace synthetic base oils, which offers economic advantages. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a schematic process diagram for producing lubricant base oil using hydrocracked liquid gas oil (t-LGO) according to one embodiment of the present disclosure. [Figure 2] 1 is a plot showing UV absorbance measurements of lubricant base oils according to one embodiment of the present disclosure. [Figure 3] 1 shows sulfuric acid color test results for a lubricating base oil according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0029] The objectives, particular advantages, and novel features of the present disclosure will become more apparent from the following detailed description and preferred embodiments in conjunction with the accompanying drawings, but the present disclosure is not necessarily limited thereto. Furthermore, in describing the present disclosure, if it is determined that a detailed description of related publicly known technologies may unnecessarily obscure the gist of the present disclosure, the detailed description will be omitted.

[0030] The term "unconverted oil (UCO)" as used in this disclosure means unreacted oil that has been fed to a hydrocracking process for the production of fuel oil, but has not undergone the hydrocracking reaction.

[0031] Also, the term "processed liquid gas oil (t-LGO)" as used in this disclosure means liquid gas oil separated by fractional distillation after a hydrocracking step.

[0032] Lubricating base oil The present disclosure provides mineral oil-based lubricant base oils with improved low temperature performance having low kinematic viscosity and low pour point derived from feedstocks comprising treated liquid gas oil (t-LGO).

[0033] The treated liquid gas oil (t-LGO) disclosed herein is derived from the product of a hydrocracking process for producing fuel oil, and the treated liquid gas oil (t-LGO) can be introduced into a catalytic dewaxing process (CDW) before or after harvesting. That is, according to one embodiment of the present disclosure, the fractionated treated liquid gas oil (t-LGO) from the product of the hydrocracking process can be subsequently subjected to a catalytic dewaxing process, and a lubricant base oil with desired properties can be separated and recovered from the product of the catalytic dewaxing process. According to another embodiment of the present disclosure, a portion of the product of the hydrocracking process is supplied to a catalytic dewaxing process, and an oil corresponding to the properties of the treated liquid gas oil (t-LGO) from the product of the catalytic dewaxing process is separated and recovered and used as a lubricant base oil.

[0034] To facilitate clear understanding, Figure 1 shows a schematic process diagram for producing lubricant base oil using hydrocracked liquid gas oil (t-LGO) according to one embodiment of the present disclosure. Figure 1 is a schematic process diagram for producing mineral oil-based lubricant base oil using liquid gas oil (t-LGO) processed in a fuel oil hydrogenation process using vacuum gas oil (VGO) as a raw material. Referring to Figure 1, in one embodiment of the present disclosure, atmospheric residue (AR) separated from an atmospheric distillation unit (CDU) is distilled in a vacuum distillation step (V) to separate it into vacuum gas oil (VGO) and vacuum residue (VR), and the vacuum gas oil (VGO) is sequentially supplied to a hydrotreating step (HDT) and a hydrocracking step (HDC). The vacuum gas oil (VGO) from the hydrocracking step (HDC) is subsequently fed to a fractional distillation step (Fs) to separate treated liquid gas oil (t-LGO), which is then fed to a catalytic dewaxing step (CDW) to recover the lubricating base oil of the present disclosure from the product of the catalytic dewaxing step.

[0035] Hydrotreating (HDT) is a process for removing impurities such as sulfur, nitrogen, oxygen, and metal components contained in petroleum fractions such as vacuum gas oil (VGO). After hydrotreating (HDT), the petroleum fraction is converted into hard hydrocarbons through hydrocracking in hydrocracking (HDC). The hydrotreating (HDT) and hydrocracking (HDC) processes can be performed under any conventional process conditions as long as they do not interfere with the production of treated liquid gas oil (t-LGO) used in the present disclosure.

[0036] According to one embodiment of the present disclosure, the treated liquid gas oil (t-LGO) may have a 10% distillation temperature of 250°C or less and a 50% distillation temperature of 350°C or less, preferably a 10% distillation temperature of 240°C or less and a 50% distillation temperature of 340°C or less, and more preferably a 10% distillation temperature of 230°C or less and a 50% distillation temperature of 330°C or less, in a simulated distillation test according to ASTM D2887. The ASTM D2887 test is a method for analyzing the boiling point of a sample using a simulated distillation test by gas chromatography. By gradually increasing the temperature of the treated liquid gas oil (t-LGO), hydrocarbon components in the t-LGO are eluted through a capillary column, and the boiling point distribution can be determined by comparing it with a standard measured under the same conditions. If the distillation temperature is outside this range, the kinematic viscosity and low-temperature viscosity of the base oil product produced using the t-LGO may increase, adversely affecting the performance of the lubricating oil.

[0037] The treated liquid gas oil (t-LGO) may have a specific gravity of 0.81 to 0.87, preferably 0.82 to 0.86. While the specific gravity does not directly affect the performance of the lubricating base oil, it is useful for determining whether the treated liquid gas oil (t-LGO) contains foreign matter.

[0038] The treated liquid gas oil (t-LGO) may have a kinematic viscosity of 5.0 cSt or less, preferably 4.7 cSt or less, and more preferably 4.5 cSt or less at 40°C, and may have a kinematic viscosity of 2.0 cSt or less, preferably 1.8 cSt or less, and more preferably 1.6 cSt or less at 100°C. Kinematic viscosity refers to the value obtained by dividing the viscosity of a fluid by the density of the fluid. Generally, the viscosity of a lubricating base oil refers to kinematic viscosity, and the measurement temperatures are defined as 40°C and 100°C according to the viscosity classification of the International Organization for Standardization (ISO).

[0039] The processed liquid gas oil (t-LGO) may have a pour point of 5°C or less, preferably -5°C or less, more preferably -10°C or less, and most preferably -15°C or less. When oil is cooled, its viscosity gradually increases, it loses its fluidity, and it begins to solidify. The temperature at which this occurs is called the freezing point, and the pour point refers to the temperature at which fluidity can be observed before the freezing point is reached. It is usually a temperature 2.5°C higher than the freezing point.

[0040] The treated liquid gas oil (t-LGO) may contain sulfur and nitrogen at 2.0 wt% or less, respectively. Preferably, the treated liquid gas oil (t-LGO) may contain sulfur and nitrogen at 1.0 wt% or less, respectively. Even trace amounts of sulfur and nitrogen can adversely affect the stability of catalysts in subsequent processes and the final product, so they are typically removed by hydrotreating (HDT) as described above.

[0041] According to one embodiment of the present disclosure, the feedstock can contain at least 90%, preferably at least 95%, of treated liquid gas oil (t-LGO). Most preferably, the feedstock can be composed of 100% treated liquid gas oil (t-LGO). If the feedstock contains less than 90% treated liquid gas oil (t-LGO), it becomes difficult to obtain the lubricating base oil with improved low-temperature performance desired by the present disclosure.

[0042] As described above, in the present disclosure, the treated liquid gas oil (t-LGO) is introduced into a catalytic dewaxing (CDW) process before or after collection. The CDW process is a process for reducing or removing N-paraffins, which impair low-temperature properties, through an isomerization or cracking reaction. Therefore, by undergoing the catalytic dewaxing reaction, the liquid gas oil can have excellent low-temperature properties, thereby meeting the pour point specifications of the desired lubricating base oil. According to one embodiment of the present invention, the CDW process is carried out at a reaction temperature of 250 to 410°C and a pressure of 30 to 200 kg / cm. 2Reaction pressure, 0.1~3.0hr -1 Space velocity (LHSV) and 150 to 1000 Nm 3 / m 3 The reaction can be carried out under the condition of a volume ratio of hydrogen to feedstock of 0.1 to 0.25.

[0043] In addition, the catalyst that can be used in the dewaxing process includes a support having an acid site selected from a molecular sieve, alumina, and silica-alumina, and one or more metals having a hydrogenation function selected from elements of Groups 2, 6, 9, and 10 of the periodic table. Among the metals of Groups 9 and 10 (i.e., Group VIII), Co, Ni, Pt, and Pd are preferred, and among the metals of Group 6 (i.e., Group VIB), Mo and W are preferred. The carrier having the acid site may be a molecular sieve, alumina, silica-alumina, etc. Among them, the molecular sieve refers to a crystalline aluminosilicate (zeolite), SAPO, ALPO, etc., and may include medium pore molecular sieves having a 10-membered oxygen ring, such as SAPO-11, SAPO-41, ZSM-11, ZSM-22, ZSM-23, ZSM-35, and ZSM-48, and large pore molecular sieves having a 12-membered oxygen ring.

[0044] In the present disclosure, the fraction that has undergone the dewaxing step is further introduced into a hydrofinishing step (HDF) in the presence of a hydrofinishing catalyst. The hydrofinishing step (HDF) is a step for ensuring stability by removing olefins and polycyclic aromatics from the dewaxed fraction in the presence of a hydrofinishing catalyst according to the required specifications for each product. In particular, from the perspective of producing naphthenic lubricant base oils, this step is a step for finally controlling the aromatic content and gas hygroscopicity. According to one embodiment of the present invention, the hydrofinishing step (HDF) is carried out at a temperature of 150 to 300°C and a pressure of 30 to 200 kg / cm. 2 pressure, 0.1~3h -1 Space velocity (LHSV) and 300 to 1500 Nm 3 / m 3The reaction can be carried out under the following conditions: a volume ratio of hydrogen to the inflowing fraction of 0.1 to 0.25;

[0045] The catalyst used in the hydrofinishing step is a metal supported on a carrier, and the metal includes one or more metals selected from Groups 6, 8, 9, 10, and 11 elements that have a hydrogenation function. Preferably, metal sulfides such as Ni-Mo, Co-Mo, or Ni-W, or precious metals such as Pt or Pd can be used. The carrier for the catalyst used in the hydrofinishing step can be silica, alumina, silica-alumina, titania, zirconia, or zeolite, which have a high surface area. Preferably, alumina or silica-alumina can be used.

[0046] Meanwhile, the lubricating base oils of the present disclosure, produced from feedstocks containing processed liquid gas oil (t-LGO) as described above, may have a kinematic viscosity of 9.0 cSt or less, preferably 8.0 cSt or less, and more preferably 7.0 cSt or less at 40°C. The lubricating base oils may also have a kinematic viscosity of 2.5 cSt or less, preferably 2.3 cSt or less, and more preferably 2.0 cSt or less at 100°C. The lubricating base oils may also have a pour point of -50°C or less, preferably -60°C or less. Regarding the low-temperature performance of lubricating base oils, kinematic viscosity and pour point are representative properties that can be used to assess low-temperature performance. The required viscosity of a lubricating base oil varies depending on the purpose of the lubricating base oil. While the kinematic viscosity of a fluid increases as the temperature decreases, a lower kinematic viscosity is preferred for lubricating base oils of the present disclosure, which are intended to improve low-temperature performance. Furthermore, the lower the pour point of a lubricating base oil, the more likely it is to be used in lower-temperature environments. Therefore, the lubricating base oils of the present disclosure have the advantage of being applicable to extreme regions or lubricating oil products requiring high low-temperature performance.

[0047] According to one embodiment of the present disclosure, the lubricating base oil may have an average carbon number per hydrocarbon molecule of 14 to 25, preferably 14 to 22, and more preferably 14 to 20. If the average carbon number is less than 14, problems such as excessively low flash point and evaporation loss may occur, and if the average carbon number is more than 25, problems such as excessively high low-temperature performance (low-temperature viscosity and pour point) may occur, making it difficult to satisfy the performance requirements of the lubricating oil itself.

[0048] According to one embodiment of the present disclosure, the content of hydrocarbon molecules having 13 or fewer carbon atoms in the lubricating base oil may be 25% by weight or less, preferably 22% by weight or less, and more preferably 20% by weight or less, based on the total lubricating base oil. If the content of hydrocarbon molecules having 13 or fewer carbon atoms in the lubricating base oil exceeds 25% by weight based on the total lubricating base oil, problems such as a lower flash point, reduced stability at high temperatures, and increased evaporation loss, which may shorten the lubricating oil replacement cycle, may occur.

[0049] According to one embodiment of the present disclosure, the lubricating base oil may contain 10 to 50 wt. %, preferably 15 to 50 wt. %, and more preferably 20 to 50 wt. % naphthenic hydrocarbons. If the naphthenic hydrocarbon content is less than 10 wt. %, the aniline point may increase, resulting in reduced compatibility with additives during the production of finished lubricating oils, and a reduced flash point. On the other hand, if the naphthenic hydrocarbon content exceeds 50 wt. %, the oxidative stability and thermal stability may decrease.

[0050] In the lubricating base oil of the present disclosure, the content of each type of hydrocarbon in the lubricating base oil has a significant effect on the properties of the lubricating base oil. More specifically, in the case of paraffinic hydrocarbons, the content in the lubricating base oil increases, the lubrication performance improves, the oxidation stability and thermal stability improve, and the ability to maintain viscosity despite temperature changes improves, but the flowability at low temperatures decreases. In the case of aromatic hydrocarbons, the content in the lubricating base oil increases, the compatibility with additives improves, but the oxidation stability and thermal stability decrease, and harmfulness increases. In the case of naphthenic hydrocarbons, the content in the lubricating base oil increases, the compatibility with additives improves, the flowability at low temperatures improves, but the oxidation stability and thermal stability decrease. Meanwhile, the content of each type of hydrocarbon in the lubricating base oil in the present disclosure is measured by the composition analysis method specified in the ASTM D2140 or ASTM D3238 test.

[0051] The inventors of the present invention have found that the properties of the lubricating base oils of the present invention are influenced by the following relationship: According to one embodiment of the present disclosure, the lubricating base oil has a viscosity of 0.3≦(C N +C A ) / C P ≦0.7, where C N is the weight percent of naphthenic hydrocarbons, C A is the weight percent of aromatic hydrocarbons, C P is the weight percent of the paraffinic hydrocarbon. n +C a ) / C p If the value is less than 0.3, it becomes difficult to achieve the desired low pour point of the lubricating base oil. n +C a ) / C p If the value exceeds 0.7, it becomes difficult to achieve the desired low-temperature viscosity of the lubricating base oil.

[0052] According to another embodiment of the present disclosure, the lubricating base oil has 25 wt.%≦C n +C a ≦45 wt%. n +C aIf the (C ) value is less than 25% by weight, it becomes difficult to achieve the desired low pour point of the lubricating base oil. n +C a If the % by weight of the saturation oil exceeds 45 wt %, it becomes difficult to achieve the desired low-temperature viscosity of the lubricating base oil.

[0053] According to one embodiment of the present disclosure, the lubricating base oil may also have a low-temperature viscosity of 550 cSt or less, preferably 520 cSt or less, and more preferably 500 cSt or less, when measured at −40° C. If the kinematic viscosity of the lubricating base oil exceeds 550 cSt at −40° C., the kinematic viscosity is too high and it becomes difficult for the lubricating base oil to function in cryogenic environments.

[0054] According to one embodiment of the present disclosure, the lubricating base oil may have a flash point of 110°C or higher, an evaporation loss at 150°C of 20% by weight or less, and a 5% distillation temperature of 200°C or higher in a simulated distillation test according to ASTM D2887. Preferably, the lubricating base oil may have a flash point of 120°C or higher, an evaporation loss at 150°C of 18% by weight or less, and a 5% distillation temperature of 220°C or higher in a simulated distillation test according to ASTM D2887. Since lubricating oils are applicable in various fields, they must be resistant to heat that may occur in those fields. For example, a lubricating oil with a specific flash point may ignite at temperatures higher than the flash point, making it unsuitable for use as a lubricating oil in environments requiring temperatures higher than the flash point. Furthermore, low volatility of a lubricating base oil is important for producing low-viscosity lubricating oils because it reduces oil consumption and increases oil durability. If the 5% distillation temperature in the replica distillation test is less than 200°C, the flash point and evaporation loss performance of the lubricating base oil may not be satisfied. In this disclosure, the flash point of the lubricating base oil is measured by the ASTM D92-COC method. The evaporation loss is measured by the ASTM D5800 test, but at a temperature of 150°C instead of 250°C.

[0055] lubricant products The present disclosure provides a lubricant product comprising a mineral oil-based lubricant base oil having improved low-temperature performance, the lubricant base oil being one of the lubricant base oils described above.

[0056] In one embodiment of the present disclosure, the lubricant product may contain 20 to 99 wt. % of the lubricant base oil according to the present disclosure. The content of the lubricant base oil according to the present disclosure can be adjusted in various ways depending on the application and purpose of the lubricant product, and the lubricant base oil according to the present disclosure can be appropriately blended with other mineral oil-based lubricant base oil products to meet the desired product specifications.

[0057] The finished lubricant may have a pour point of -40°C or less, preferably -45°C or less, more preferably -50°C or less.

[0058] In one embodiment according to the present disclosure, the finished lubricant does not contain synthetic base oil. For example, the finished lubricant does not contain PAO or ester-based base oil. By including a lubricant base oil according to the present disclosure, it is possible to produce a finished lubricant with excellent low-temperature performance without using expensive PAO or ester-based lubricant base oils.

[0059] In one embodiment of the present disclosure, the finished lubricant may further include additives such as, but not limited to, antioxidants, rust inhibitors, detergents / dispersants, antifoam agents, viscosity improvers, viscosity index improvers, extreme pressure agents, pour point depressants, corrosion inhibitors, or emulsifiers, as long as they are additives commonly added to finished lubricants.

[0060] The lubricant products can be used in fields or environments requiring low-temperature performance and can replace lubricant products made with conventional PAO or ester-based lubricant base oils. Examples of the lubricant products include, but are not limited to, automotive shock absorber oils, hydraulic fluids for arctic regions, and electrical insulating oils.

[0061] In one embodiment of the present disclosure, the lubricant product can be used as a white oil for use in plastics, polishing agents, the paper industry, textile lubricants, insecticide base oils, pharmaceutical compositions, cosmetics, and the lubrication of food and food processing machinery.

[0062] Preferred examples are presented below to aid in understanding the present disclosure, but the following examples are provided merely to facilitate understanding of the present disclosure, and the present disclosure is not limited to these examples. [Example]

[0063] Example 1. Manufacturing of lubricating base oil (YUBASE1) t-LGO was obtained by fractional distillation of the product of a fuel oil hydrogenation process using vacuum gas oil (VGO) as a raw material. The properties of the obtained t-LGO are shown in Table 2 below, and the values ​​of each property were measured according to ASTM methods.

[0064] [Table 2]

[0065] The resulting t-LGO was fed to a catalytic dewaxing reactor, and the product of the catalytic dewaxing step was fed to a hydrofinishing reactor. The process conditions for the catalytic dewaxing reactor and the hydrofinishing reactor are shown in Table 3 below. The product of the hydrofinishing reactor was then recovered as lubricating base oil.

[0066] [Table 3]

[0067] 2. Analysis of the properties and composition of the produced lubricating base oil The lubricating base oils prepared as described above were analyzed for their compositions and properties, which are shown in Tables 4 and 5, respectively.

[0068] [Table 4]

[0069] The content of each hydrocarbon type in the lubricating base oil was measured according to the ASTM D2140 test method. As shown in Table 4, the (C N +C A ) / C P is in the range of 0.3 to 0.7, and C N +C A It can be confirmed that the content of the hydroxybenzoate is in the range of 25 wt% to 45 wt%.

[0070] [Table 5]

[0071] As shown in Table 5, the lubricating base oil of the present disclosure is not a synthetic base oil but a mineral oil-based lubricating base oil. However, it can be confirmed that the lubricating base oil has low kinematic viscosity and excellent low-temperature performance without the addition of other additives.

[0072] As mentioned above, PAOs have traditionally been used as lubricating base oils in applications requiring low-temperature performance. Therefore, determining whether the lubricating base oils disclosed herein can replace PAOs is an important objective of this disclosure. The properties of the lubricating base oil (YUBASE1, hereinafter referred to as "YU-1") and the PAOs are compared in Table 6 below.

[0073] [Table 6]

[0074] As shown in Table 6 above, the lubricating base oil (YU-1) of the present disclosure has kinematic viscosity and pour point that are superior to or similar to those of PAO.

[0075] 3. Performance verification of lubricant products In order to confirm the low temperature performance of the lubricating base oil according to the present disclosure when manufactured into a lubricating oil product, a lubricating base oil (YU-1) having the composition shown in Table 4 and the properties shown in Table 5 was manufactured, and its performance was confirmed.

[0076] (1) Automotive shock absorbing oil YU-1 was used to produce a lubricating oil product for use in automobile shock absorbers, the composition of which is shown in Table 7 below.

[0077] [Table 7]

[0078] The properties of the shock absorbing oil are shown in Table 8.

[0079] [Table 8]

[0080] As shown in Table 8, it can be confirmed that by using YU-1 lubricating base oil, it is possible to produce shock absorbing oil with excellent performance even without using PAO.

[0081] (2) ISO VG 32 hydraulic oil for arctic regions YU-1 was blended with YU-L3, a Group III base oil available from SK Lubricating Oil Co., Ltd., to produce an arctic hydraulic oil with an ISO viscosity grade of 32. The properties of YU-L3 are listed in Table 9 below.

[0082] [Table 9]

[0083] The composition of the hydraulic oil for arctic regions is shown in Table 10 below.

[0084] [Table 10]

[0085] The properties of the hydraulic oil for arctic regions are shown in Table 11.

[0086] [Table 11]

[0087] As shown in Table 11, the hydraulic oils blended with YU-1 and YU-L3 have low Brookfield viscosities at -40°C and low pour points, demonstrating excellent low-temperature performance. This demonstrates that it is possible to design mineral oil-based lubricating oil products with excellent low-temperature performance without using PAOs.

[0088] (3) ISO VG 15 hydraulic oil for arctic regions YU-1 was used to prepare an arctic hydraulic oil having an ISO viscosity grade of 15. The composition of the arctic hydraulic oil is shown in Table 12 below.

[0089] [Table 12]

[0090] The properties of the hydraulic oil for arctic regions are shown in Table 13 below.

[0091] [Table 13]

[0092] As shown in Table 13, the hydraulic oil produced using YU-1 has a low Brookfield viscosity at -40°C and a low pour point, indicating that it is a product with excellent low-temperature performance.

[0093] (4) Electrical insulating oil An electrical insulating oil was produced by blending YU-1 with YU-3, a Group III base oil available from SK Lubricant Concentrate Co., Ltd. The properties of YU-3 are shown in Table 14 below.

[0094] [Table 14]

[0095] The properties of the electrical insulating oils were tested by varying the content ratio of the two types of base oils. The test results are summarized in Table 15 below.

[0096] [Table 15]

[0097] As shown in Table 15, as the content of YU-1 increases, the flash point decreases, but the viscosity and pour point also improve.The above results show that by appropriately blending YU-1 with other mineral oil-based lubricating base oils, it is possible to design electrical insulating oils that meet international standards.

[0098] (5) Applicability of white oil Experiments were conducted to confirm whether YU-1 can be used as a food-grade white oil.

[0099] 1) Measurement of UV absorbance To confirm whether or not the oil meets the criteria for food-grade white oil as defined by the U.S. Food and Drug Administration (FDA), YU-1 was directly irradiated with light and its UV absorbance in the wavelength range of 260 to 350 nm was measured. The measurement results are shown in Figure 2.

[0100] Experimental results confirmed that the UV absorbance of YU-1 was less than 0.1 in the above wavelength range. The maximum UV absorbance of food-grade white oil as specified by the U.S. Food and Drug Administration (FDA) is 0.1. This refers to the UV absorbance value measured using the DMSO extraction method according to the IP 346 method. It is known that UV absorbance measured using the DMSO extraction method is generally lower than the absorbance measured by directly irradiating the sample with light. Therefore, in the case of YU-1 of the present disclosure, since the absorbance measured using direct light is less than 0.1, it is obvious that the UV absorbance measured using the DMSO extraction method will be even lower. Therefore, it was determined that YU-1 of the present disclosure meets the food grade standard.

[0101] 2) Sulfuric acid color test To confirm whether the amount of impurities contained in YU-1 was within the range that would allow it to be used as a white oil, a qualitative experiment was conducted using sulfuric acid. The sulfuric acid color test was conducted based on the test method specified in ASTM D565. The results of the sulfuric acid color test are shown in Figure 3.

[0102] As shown in Figure 3, the discoloration of YU-1 was confirmed to be less than that of the standard. Therefore, it can be seen that the amount of impurities in YU-1 is within the range that can be used as white oil.

[0103] The UV absorbance measurement and sulfuric acid coloration test confirmed that YU-1 can be used as a food-grade white oil.

[0104] Any simple modifications or variations of the present disclosure should fall within the scope of the present disclosure, and the specific scope of protection of the present disclosure will be defined by the appended claims.

Claims

1. 1. A mineral oil-based lubricating base oil having improved low temperature performance, comprising: The lubricating base oil has a kinematic viscosity of 9.0 cSt (40°C) or less, a kinematic viscosity of 2.5 cSt (100°C) or less, and a pour point of -60°C or less; the lubricating base oil comprises 20 to 37.5 wt. % naphthenic hydrocarbons; The lubricating base oil satisfies the following relationship: 0.3≦(Cn+Ca) / Cp≦0.7; the lubricating base oil containing no more than 0.9 wt. % aromatic hydrocarbons; A mineral oil-based lubricating base oil with improved low temperature performance, wherein Cn is the weight percent of naphthenic hydrocarbons, Ca is the weight percent of aromatic hydrocarbons, and Cp is the weight percent of paraffinic hydrocarbons.

2. 2. The mineral oil-based lubricating base oil with improved low temperature performance of claim 1, wherein the lubricating base oil has a range of 25 wt.% < Cn + Ca < 38.4 wt.%, where Cn is the weight percent of naphthenic hydrocarbons and Ca is the weight percent of aromatic hydrocarbons.

3. 2. The mineral oil-based lubricating base oil with improved low temperature performance of claim 1, wherein the lubricating base oil has a kinematic viscosity of 500 cSt (-40°C) or less.

4. 2. The mineral oil-based lubricating base oil with improved low temperature performance according to claim 1, wherein the lubricating base oil has a flash point of 110°C or higher, an evaporation loss at 150°C of 20% by weight or less, and a 5% distillation temperature of 200°C or higher in a simulated distillation test according to ASTM D2887.

5. A lubricating oil product comprising 20 to 99 wt % of the lubricating base oil according to any one of claims 1 to 4 and having a pour point of -40°C or less.

6. 6. The finished lubricant of claim 5, wherein the finished lubricant is free of synthetic base oils.

7. 6. The finished lubricant of claim 5, wherein the finished lubricant does not contain polyalphaolefins (PAO) or ester-based base oils.

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