Method for producing transformer oil base oil from naphthenic base distillate oil, extra-high voltage transformer oil and base oil, I-type transformer oil and base oil

Abstract

The invention provides a method for producing transformer oil base oil from naphthenic base distillate oil, extra-high voltage transformer oil, extra-high voltage transformer oil base oil, I-type transformer oil and I-type transformer oil base oil, and relates to the technical field of transformer oil base oil. Under the medium pressure condition, the naphthenic base distillate oil is sequentially subjected to hydrotreatment, hydrodewaxing treatment and refining treatment; fractionating the refined generated oil, extracting the extra-high voltage transformer oil base oil from a vacuum tower at the temperature of 300-325 DEG C in a side-draw manner, and mixing a product extracted from the vacuum tower at the temperature of 275-300 DEG C in the side-draw manner with a product extracted from the bottom of the vacuum tower at the temperature of 325 DEG C or above according to the side-draw yield to obtain the I-type transformer oil base oil. According to the method, the base oil of the type I transformer oil is produced while the base oil of the extra-high voltage transformer oil is produced through hydrogenation, the device utilization rate is high, the economic benefit is good, the content of cycloalkane in the base oil of the extra-high voltage transformer oil is high, the content of bicyclic aromatic hydrocarbon is 1%-2%, the antioxidant stability and the gassing resistance are both considered, and the base oil of the type I transformer oil is low in pour point and high in yield.

Description

Technical Field

[0001] The invention relates to the technical field of transformer oil base oil, and in particular to a method for producing transformer oil base oil from cycloalkane distillate oil, ultra-high voltage transformer oil and base oil, and Class I transformer oil and base oil. Background Art

[0002] At present, the production of UHV transformer oil is mainly based on cycloalkyl or paraffin-based crude oil lubricating oil fractions, using high-pressure full hydrogenation technology such as high-pressure hydrogenation treatment or cracking-high-pressure hydrodecondensation or isomerization dewaxing-high-pressure supplementary refining. High-pressure full hydrogenation technology can achieve deep removal of aromatics, and the electrical properties and oxidation resistance of the transformer oil products produced are good; however, due to the low aromatic content, especially the basic removal of dicyclic aromatics, it is necessary to blend the base oil or add anti-gassing additives, which increases the production cost of transformer oil; in addition, the high-pressure hydrogenation unit has a complex process flow, a large one-time investment scale, and high requirements for operational safety. For refineries with smaller processing scales, its applicability is not high, especially when the distillation range of the processed raw materials is not higher than 370°C, the high-pressure hydrogenation technology is prone to excessive processing of raw materials, resulting in waste of resources and energy.

[0003] Prior art CN102660363A discloses a transformer oil, which is composed of a paraffin-based oil fraction, a cycloalkyl oil, an alkyl high-boiling substance, an antioxidant and an anti-photosensitive agent; in the transformer oil, the paraffin-based oil fraction accounts for 60wt%-75wt%, the cycloalkyl oil accounts for 19.4wt%-28.5wt%, the alkyl high-boiling substance accounts for 5wt%-10wt%, the antioxidant accounts for 0.5wt%-1.0wt%, and the anti-photosensitive agent accounts for 0.1wt%-0.5wt%; the preparation method of the transformer oil comprises the following steps: adding the paraffin-based oil fraction, the cycloalkyl oil and the alkyl high-boiling substance into a reactor, adding white clay for refining, stirring and refining and adsorbing at high temperature, adding the antioxidant and the anti-photosensitive agent after filtering, the negative pressure of the vacuum pump is 0.8kPa, and the vacuum treatment is performed 1-3 times; the kinematic viscosity of the obtained transformer oil is 6.5mm 2 / s-9.5mm 2 / s, and the breakdown voltage is 55-80KV / 2.5mm; however, it has obvious disadvantages of high cost and low yield.

[0004] The prior art also discloses a production process for commutation high-voltage transformer oil, which is composed of 290°C-325°C fraction cycloalkyl base oil, dodecylbenzene, benzotriazole, 2(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, and 2,6-di-tert-butyl-p-cresol, wherein the content of the 290°C-325°C fraction cycloalkyl base oil is 70wt%-90wt%, dodecylbenzene is 10wt%-30wt%, benzotriazole is 5-200PPm, 2(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol is 0.05wt%-3wt%, and 2,6-di-tert-butyl-p-cresol is 0-0.5wt%; the components are evenly mixed, finely filtered, vacuum dehydrated, and the finished product is produced; although the process is simple to operate and has low cost, the disadvantage is that the highly toxic 2,6-di-tert-butyl-p-cresol is used as an antioxidant, which will pollute the human body and the environment.

[0005] Prior art CN102144018A uses heavy reforming oil as an anti-gassing additive. Although it has a significant effect on improving the gassing property of transformer oil, its pour point is high and its flash point is low. Prior art CN103113963A uses dodecylbenzene as an anti-gassing additive to produce ultra-high voltage transformer oil, but dodecylbenzene is expensive and has a high pour point. Prior art CN102676215A uses transformer oil solvent refining extract oil or a mixed oil of it and cycloalkyl transformer oil fraction as raw materials, and produces anti-gassing additives through a process of solvent refining-liquid phase denitrogenation and clay refining. It has the problems of low yield of target product, difficult operation, and excessive use of clay and denitrogenating agent.

[0006] The prior art CN1089517243A discloses that 300°C-350°C narrow-fraction cycloalkyl oil is used as raw material, and a hydrogenation treatment-liquid phase denitrification-clay refining process is performed to achieve dearomatization, desulfurization, denitrification, and decolorization, and then an antioxidant, a pour point depressant, an anti-ultraviolet agent, an antioxidant and an anti-corrosion agent and other additives are added, and then multi-stage vacuum filtration and vacuum pump negative pressure treatment are performed to obtain AC / DC transformer oil. The disadvantages of the method are that the operation is complicated and the energy consumption is high, and clay refining is also required, which brings about the problem of handling waste clay. At the same time, many types of additives are added, which also increases the production cost.

[0007] The prior art CN108977224B uses a narrow fraction of 290°C-330°C obtained by direct liquefaction and fractionation of coal as a raw material, and undergoes a hydrofining-hydrogenation reforming-supplementary refining process at a reaction pressure of 15.0 MPa to obtain two types of transformer oil base oils by changing the process conditions. The two types of transformer oil base oils are blended in a certain proportion to produce transformer oil base oil; the disadvantage is that two production lines are required to obtain two types of transformer oil base oils with different aromatic hydrocarbon contents, which are then blended in a certain proportion, and precious metals are used as supplementary refining catalysts, which increase the production cost of transformer oil.

[0008] In summary, in the prior art, transformer oil base oil needs to be refined with bleaching clay for denitrification and decolorization, which brings about the problem of waste bleaching clay treatment; the use of high-pressure hydrogenation technology has the problems of complex process flow and large one-time investment scale; the use of two transformer oil base oils with different aromatic hydrocarbon contents to blend and produce high-quality transformer oil base oil has the problems of complex process flow and high production cost.

[0009] In view of this, the present invention is proposed. Summary of the invention

[0010] One of the purposes of the present invention is to provide a method for producing transformer oil base oil from cycloalkane distillate oil, which can produce Class I transformer oil base oil while hydrogenating ultra-high voltage transformer oil base oil, and has the advantages of high device utilization rate and good economic benefit.

[0011] The second object of the present invention is to provide a UHV transformer oil base oil, which has a high cycloalkane content and a dicyclic aromatic hydrocarbon content between 1% and 2%. It can ensure good anti-gassing properties without adding anti-gassing components, while also taking into account better antioxidant stability.

[0012] A third object of the present invention is to provide an ultra-high voltage transformer oil that can meet the index requirements of the State Grid for ultra-high voltage transformer oil.

[0013] A fourth object of the present invention is to provide a Class I transformer oil base oil having a lower aromatic content and better sensitivity to antioxidants.

[0014] A fifth object of the present invention is to provide a Class I transformer oil that can meet the I-40# index requirements in GB2536-2011.

[0015] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0016] In a first aspect, a method for producing transformer oil base oil from cycloalkane distillate oil comprises the following steps:

[0017] (a) subjecting the naphthenic distillate oil to a hydrogenation treatment, a hydrodecondensation treatment and a refining treatment in sequence under a reaction pressure of not more than 10.0 MPa to obtain a refined product oil;

[0018] (b) fractionating the refined product oil in a vacuum tower, extracting a side line at 300° C.-325° C. of the vacuum tower to obtain a UHV transformer oil base oil, and mixing a side line product at 275° C.-300° C. of the vacuum tower with a bottom product at above 325° C. of the vacuum tower according to a side line yield to obtain a Class I transformer oil base oil.

[0019] Furthermore, the reaction pressure is 8.0MPa-10.0MPa.

[0020] Further, the naphthenic distillate oil includes at least one of naphthenic normal second-line distillate oil and naphthenic minus first-line distillate oil;

[0021] Preferably, the cycloalkane distillate oil is a cycloalkane normal second-line distillate oil.

[0022] Further, the reaction temperature of the hydrotreatment is 300°C-370°C;

[0023] Preferably, the volume ratio of hydrogen to cycloalkyl distillate oil in the hydroprocessing is (600-1200):1.

[0024] Furthermore, the reaction temperature of the hydrodecondensation treatment is 280°C-340°C;

[0025] Preferably, the volume ratio of hydrogen in the hydrodecondensation treatment to the generated oil obtained by the hydrotreatment is (600-1200):1.

[0026] Further, the reaction temperature of the refining treatment is 290°C-360°C;

[0027] Preferably, the volume ratio of hydrogen in the refining treatment to the product oil obtained by the hydrodecondensation treatment is (600-1200):1.

[0028] In a second aspect, a UHV transformer oil base oil is prepared by any of the preparation methods described above;

[0029] Preferably, the sulfur content of the UHV transformer oil base oil is less than 1.0 mg / kg, the nitrogen content is less than 1.0 mg / kg, and the total aromatics is less than 10%;

[0030] Preferably, the pour point of the UHV transformer oil base oil is less than -57°C, and the kinematic viscosity at 40°C is less than 8.0 mm 2 / s, closed cup flash point>140℃.

[0031] In a third aspect, a UHV transformer oil comprises the UHV transformer oil base oil and an antioxidant;

[0032] Preferably, the added weight percentage of the antioxidant is 0.3%±0.05%;

[0033] Preferably, the aniline point of the UHV transformer oil is 72°C-78°C, the oxidation stability at 120°C for 500h, the total acid value is <0.08mgKOH / g, and the sludge is <0.004%.

[0034] In a fourth aspect, a Class I transformer oil base oil is prepared by any of the methods described above;

[0035] Preferably, the sulfur content of the Class I transformer oil base oil is less than 1.0 mg / kg, the nitrogen content is less than 1.0 mg / kg, and the total aromatics is less than 10%;

[0036] Preferably, the pour point of the Class I transformer oil base oil is less than -57°C, and the kinematic viscosity at 40°C is less than 12.0 mm 2 / s, closed cup flash point>140℃.

[0037] A fifth aspect is a Class I transformer oil, comprising the Class I transformer oil base oil and an antioxidant;

[0038] Preferably, the added weight percentage of the antioxidant is 0.3%±0.05%;

[0039] Preferably, the Class I transformer oil has an oxidation stability at 120° C. for 500 h, a total acid value of <0.17 mgKOH / g, and oil sludge of <0.0056%.

[0040] Compared with the prior art, the present invention has at least the following beneficial effects:

[0041] The invention provides a method for producing transformer oil base oil from cycloalkane distillate oil. The method uses cycloalkane distillate oil as a raw material at medium pressure (reaction pressure ≤ 10.0 MPa) and can use a non-precious metal catalyst to sequentially perform hydrogenation treatment, hydrodecondensation treatment, refining treatment and fractionation process, so as to directly obtain ultra-high voltage transformer oil base oil and Class I transformer oil base oil. The obtained ultra-high voltage transformer oil base oil has not only a high content of cycloalkanes, but also a mass content of dicyclic aromatic hydrocarbons between 1% and 2%. The content of dicyclic aromatic hydrocarbons can ensure that the base oil has good anti-gassing property without adding anti-gassing components, and can also make the base oil have good anti-oxidation stability. The obtained Class I transformer oil base oil has a low pour point and a high product yield. The method realizes the production of Class I transformer oil base oil by hydrogenation of an apparatus while producing ultra-high voltage transformer oil base oil, and has the advantages of high apparatus utilization rate and good economic benefit.

[0042] The UHV transformer oil base oil provided by the present invention has a high cycloalkane content and a bicyclic aromatic hydrocarbon content of 1% to 2%. It can ensure good anti-gassing performance without adding anti-gassing components, while taking into account good anti-oxidation stability.

[0043] The ultra-high voltage transformer oil provided by the present invention can meet the index requirements of the State Grid for ultra-high voltage transformer oil.

[0044] The type I transformer oil base oil provided by the present invention has a lower aromatic hydrocarbon content and better sensitivity to antioxidants.

[0045] The Class I transformer oil provided by the present invention can meet the I-40# index requirements in GB2536-2011. DETAILED DESCRIPTION

[0046] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] According to a first aspect of the present invention, there is provided a method for producing transformer oil base oil from cycloalkane distillate oil, comprising the following steps:

[0048] (a) subjecting the naphthenic distillate oil to a hydrogenation treatment, a hydrodecondensation treatment and a refining treatment in sequence under a reaction pressure of not more than 10.0 MPa to obtain a refined product oil;

[0049] It should be noted that the raw oil is mixed with hydrogen for hydrogenation treatment, which can remove heteroatoms such as sulfur, nitrogen and oxygen in the raw material, saturate aromatic hydrocarbons, and obtain hydrotreated product oil; the hydrotreated product oil is mixed with hydrogen for hydrodecondensation treatment, which can selectively remove high-condensation point macromolecular normal alkanes to obtain hydrodecondensation product oil; the hydrodecondensation product oil is mixed with hydrogen for supplementary refining treatment, which can further saturate olefins and aromatic hydrocarbons to obtain refined product oil;

[0050] (b) the refined product oil is subjected to stripping and vacuum fractionation (i.e., fractionation treatment is performed in a vacuum tower); a side line extraction at 300° C. to 325° C. of the vacuum tower obtains a UHV transformer oil base oil; a side line extraction product at 275° C. to 300° C. of the vacuum tower is mixed with a bottom extraction product at more than 325° C. of the vacuum tower according to the side line yield to obtain a Class I transformer oil base oil.

[0051] Under medium pressure (reaction pressure ≤ 10.0 MPa), the present invention adopts cycloalkane distillate oil as raw material oil for reaction, and can obtain ultra-high voltage transformer oil base oil at 300° C.-325° C. of the vacuum tower by adjusting the reaction gradation of the hydrogenation catalyst, wherein the sulfur content is less than 1.0 mg / kg, the nitrogen content is less than 1.0 mg / kg, the total aromatics content is less than 10%, and the content of dicyclic aromatics is 1.0%-2.0%; the pour point of the obtained ultra-high voltage transformer oil base oil is less than -57° C., and the kinematic viscosity at 40° C. is less than 8.0 mm 2 / s, closed cup flash point>140℃; since the UHV transformer oil base oil retains 1%-2% of dicyclic aromatic hydrocarbons, which are ideal components for anti-gassing, there is no need to add anti-gassing components. The UHV transformer oil product obtained by adding antioxidants to the base oil can meet the index requirements of the State Grid for UHV transformer oil.

[0052] Under medium pressure (reaction pressure ≤ 10.0 MPa), the present invention adopts cycloalkane distillate oil as raw material oil for reaction, and adjusts the reaction gradation of hydrogenation catalyst, and mixes the side line product of 275° C.-300° C. of vacuum tower with the bottom product of more than 325° C. according to the side line yield, so as to obtain Class I transformer oil base oil, wherein the sulfur content is less than 1.0 mg / kg, the nitrogen content is less than 1.0 mg / kg, and the total aromatics is less than 10%; the pour point of the obtained Class I transformer oil base oil is less than -57° C., and the kinematic viscosity at 40° C. is less than 12.0 mm 2 / s, closed cup flash point>140℃; since the Class I transformer oil base oil has a low aromatic content, it has a good sensitivity to antioxidants. The Class I transformer oil product obtained by adding antioxidants to the base oil can meet the I-40# index requirements in GB2536-2011.

[0053] In summary, the method for producing transformer oil base oil from cycloalkane distillate oil provided by the present invention uses cycloalkane distillate oil as raw material at medium pressure (reaction pressure≤10.0MPa), can adopt non-precious metal catalyst, and sequentially carry out hydrogenation treatment, hydrodecondensation treatment, refining treatment and fractionation process, so as to directly obtain ultra-high voltage transformer oil base oil and Class I transformer oil base oil. The obtained ultra-high voltage transformer oil base oil not only has high cycloalkane content, but also has a bicyclic aromatic hydrocarbon content of 1%-2% by mass. The bicyclic aromatic hydrocarbon content can ensure that the base oil has good anti-gassing property without adding anti-gassing components, and can also make the base oil have better anti-oxidation stability. The obtained Class I transformer oil base oil has low pour point and high product yield. The method of the present invention realizes the production of ultra-high voltage transformer oil base oil by hydrogenation of the device and the production of Class I transformer oil base oil at the same time, and has the advantages of high device utilization rate and good economic benefit.

[0054] At the same time, the present invention also solves the problem of waste clay caused by using clay to refine base oil, the problem of complex process and large equipment investment caused by using high-pressure hydrogenation, and the problem of complex process and high production cost caused by using base oils with different aromatic contents to blend.

[0055] In the present invention, the cycloalkyl distillate oil includes but is not limited to at least one of cycloalkyl normal second-line distillate oil and cycloalkyl minus first-line distillate oil, for example, cycloalkyl normal second-line distillate oil, cycloalkyl minus first-line distillate oil, or cycloalkyl normal second-line / minus first-line mixed distillate oil, but is not limited thereto, and may preferably be cycloalkyl normal second-line distillate oil.

[0056] In the present invention, the catalyst used for the hydroprocessing may be the non-precious metal catalyst disclosed in Patent ZL201611160651.2, but is not limited thereto.

[0057] In a preferred embodiment, the hydroprocessing catalyst includes but is not limited to an active metal oxide and a metal oxide promoter; wherein the active metal oxide may be a Group VIII metal oxide and / or a Group VIB metal oxide, for example, nickel oxide and / or tungsten trioxide.

[0058] In the present invention, the reaction pressure of the hydrotreatment may be 8.0 MPa-10.0 MPa, for example, 8.5 MPa, 9.0 MPa, 9.5 MPa, but is not limited thereto.

[0059] In a preferred embodiment, the reaction temperature of the hydrotreatment may be 300°C-370°C, for example, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, but not limited thereto.

[0060] In a preferred embodiment, the volume ratio of hydrogen gas to cycloalkyl distillate oil in the hydrotreatment process may be (600-1200):1, for example, 700:1, 800:1, 900:1, 1000:1, 1100:1, but not limited thereto.

[0061] The volume space velocity of the hydroprocessing can be 0.2h -1 -1.0h -1 , for example, it can be 0.3h -1 、0.4h -1 , 0.5h -1 , 0.6h -1 、0.7h -1 、0.8h -1 、0.9h -1 , but not limited to this.

[0062] In the present invention, the catalyst used in the hydrodecondensation treatment may be a non-precious metal catalyst disclosed in Patent ZL201910897903.7, but is not limited thereto.

[0063] It should be noted that the hydrodegradation catalyst can selectively remove large molecular normal alkanes with high freezing points, thereby reducing the pour point of the hydrogenated oil.

[0064] In a preferred embodiment, the active metal oxide of the hydrodegradation catalyst may be a Group VIII metal oxide and / or a Group VIB metal oxide, for example, nickel oxide and / or tungsten trioxide.

[0065] In the present invention, the reaction pressure of the hydrodecondensation treatment may be 8.0 MPa-10.0 MPa, for example, 8.5 MPa, 9.0 MPa, 9.5 MPa, but not limited thereto.

[0066] In a preferred embodiment, the reaction temperature of the hydrodecondensation treatment may be 280°C-340°C, for example, 290°C, 300°C, 310°C, 320°C, 330°C, but not limited thereto.

[0067] In a preferred embodiment, the volume ratio of hydrogen from the hydrodecondensation treatment to the oil generated by the hydrotreatment can be (600-1200):1, for example, it can be 700:1, 800:1, 900:1, 1000:1, 1100:1, but is not limited thereto.

[0068] The volumetric space velocity of the hydrodecondensation treatment can be 0.8h -1 -3.0h -1 , for example, it can be 1.0h -1 , 1.2h -1 , 1.4h -1 , 1.6h -1 , 1.8h -1 , 2.0h -1 , 2.2h -1 , 2.4h -1 , 2.6h -1 , 2.8h -1 , but not limited to this.

[0069] In the present invention, the catalyst used for the supplementary refining treatment may be a non-precious metal catalyst disclosed in Patent ZL201910952953.0, but is not limited thereto.

[0070] In a preferred embodiment, the active metal oxide of the supplementary refining treatment catalyst may be a Group VIII metal oxide and / or a Group VIB metal oxide, for example, nickel oxide and / or tungsten trioxide.

[0071] In a preferred embodiment, the reaction pressure of the supplementary refining treatment may be 8.0 MPa-10.0 MPa, for example, 8.5 MPa, 9.0 MPa, 9.5 MPa, but not limited thereto.

[0072] In a preferred embodiment, the reaction temperature of the supplementary refining treatment may be 290°C-360°C, for example, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, but is not limited thereto.

[0073] In a preferred embodiment, the volume ratio of hydrogen from the supplementary refining treatment to the oil produced by the hydrodecondensation treatment can be (600-1200):1, for example, it can be 700:1, 800:1, 900:1, 1000:1, 1100:1, but is not limited thereto.

[0074] Among them, the volume space velocity of the supplementary refining treatment can be 0.3h -1 -2.0h -1 , for example, it can be 0.4h -1 , 0.6h -1 、0.8h -1 , 1.0h -1 , 1.2h -1 , 1.4h -1 , 1.6h -1 , 1.8h -1 , but not limited to this.

[0075] A method for producing transformer oil base oil from cycloalkane distillate oil, wherein cycloalkane distillate oil is subjected to medium-pressure hydrogenation to simultaneously produce ultra-high voltage transformer oil base oil and Class I transformer oil base oil, comprising the following steps:

[0076] (1) mixing cycloalkane distillate oil (raw oil) with hydrogen, and performing hydrogenation treatment under the action of a hydrogenation catalyst to obtain a hydrogenation product oil;

[0077] (2) mixing the hydrotreated product oil with hydrogen, and performing a hydrodegradation treatment under the action of a hydrodegradation treatment catalyst to obtain a hydrodegradation product oil;

[0078] (3) mixing the hydrodecondensation product oil with hydrogen, and performing a refining treatment under the action of a supplementary refining treatment catalyst to obtain a refined product oil;

[0079] (4) The refined product oil is stripped and then vacuum fractionated, and the side line of the vacuum tower at 215°C-275°C is used to obtain the drilling fluid lubricant base oil, and the side line of the vacuum tower at 300°C-325°C is used to obtain the ultra-high voltage transformer oil base oil. The side line product of the vacuum tower at 275°C-300°C is mixed with the bottom product of the vacuum tower at >325°C according to the side line yield to obtain Class I transformer oil base oil.

[0080] According to a second aspect of the present invention, there is provided a UHV transformer oil base oil, which is prepared by any of the preparation methods described above.

[0081] The UHV transformer oil base oil provided by the present invention has a relatively high content of cycloalkanes and an appropriate content of dicyclic aromatic hydrocarbons, and has good antioxidant stability and anti-gassing properties.

[0082] In a preferred embodiment, the sulfur content of the UHV transformer oil base oil is less than 1.0 mg / kg (for example, it can be 0.8 mg / kg, 0.6 mg / kg, 0.4 mg / kg, 0.2 mg / kg, but not limited to this), the nitrogen content is less than 1.0 mg / kg (for example, it can be 0.8 mg / kg, 0.6 mg / kg, 0.4 mg / kg, 0.2 mg / kg, but not limited to this), and the total aromatics are less than 10% (for example, it can be 8%, 6%, 4%, but not limited to this).

[0083] In a preferred embodiment, the pour point of the UHV transformer oil base oil is less than -57°C (for example, -59°C, -60°C, -61°C, but not limited thereto), and the kinematic viscosity at 40°C is less than 8.0 mm 2 / s (for example, it can be 7.5mm 2 / s、7.0mm 2 / s, 6.5mm 2 / s, but not limited thereto), closed cup flash point>140°C (for example, 141°C, 142°C, 143°C, but not limited thereto).

[0084] According to a third aspect of the present invention, there is provided an ultra-high voltage transformer oil, comprising the ultra-high voltage transformer oil base oil and an antioxidant.

[0085] In the present invention, UHV transformer oil is obtained by adding a proper amount of antioxidant to transformer oil base oil; wherein the added amount of antioxidant may be 0.3%±0.05% (eg, 0.32%, 0.34%, but not limited thereto).

[0086] In a preferred embodiment, the aniline point of the ultra-high voltage transformer oil is 72°C-78°C (for example, it can be 74°C or 76°C, but not limited to this), the oxidation stability at 120°C for 500h, the total acid value is less than 0.08mgKOH / g (for example, it can be 0.06mgKOH / g or 0.04mgKOH / g, but not limited to this), and the sludge is less than 0.004% (for example, it can be 0.003% or 0.002%, but not limited to this).

[0087] The ultra-high voltage transformer oil provided by the present invention can meet the index requirements of the State Grid for ultra-high voltage transformer oil.

[0088] According to a fourth aspect of the present invention, there is provided a Class I transformer oil base oil, which is prepared by any of the methods described above.

[0089] The type I transformer oil base oil provided by the present invention has a lower aromatic hydrocarbon content and better sensitivity to antioxidants.

[0090] In a preferred embodiment, the sulfur content in the Class I transformer oil base oil is less than 1.0 mg / kg (for example, it can be 0.8 mg / kg, 0.6 mg / kg, 0.4 mg / kg, 0.2 mg / kg, but not limited to this), the nitrogen content is less than 1.0 mg / kg (for example, it can be 0.8 mg / kg, 0.6 mg / kg, 0.4 mg / kg, 0.2 mg / kg, but not limited to this), and the total aromatics is less than 10% (for example, it can be 8%, 6%, 4%, but not limited to this).

[0091] In a preferred embodiment, the pour point of the Class I transformer oil base oil is less than -57°C (for example, -59°C, -60°C, -61°C, but not limited thereto), and the kinematic viscosity at 40°C is less than 12.0 mm 2 / s (for example, it can be 11.5mm 2 / s, 11.0mm 2 / s, 10.5mm 2 / s, but not limited thereto), closed cup flash point>140°C (for example, 141°C, 142°C, 143°C, but not limited thereto).

[0092] According to a fifth aspect of the present invention, there is provided a Class I transformer oil comprising the Class I transformer oil base oil described above and an antioxidant.

[0093] In the present invention, a Class I transformer oil is obtained by adding a proper amount of antioxidant to the transformer oil base oil; wherein the added amount of the antioxidant may be 0.3%±0.05% (eg, 0.32%, 0.34%, but not limited thereto).

[0094] In a preferred embodiment, the Class I transformer oil has an oxidation stability at 120° C. for 500 h, a total acid value of less than 0.17 mgKOH / g (for example, 0.12 mgKOH / g, 0.07 mgKOH / g, but not limited thereto), and an oil sludge of less than 0.0056% (for example, 0.0053%, 0.005%, but not limited thereto).

[0095] The Class I transformer oil provided by the present invention can meet the I-40# index requirements in GB2536-2011.

[0096] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market. The physical properties of the catalysts used in the examples are shown in Table 1.

[0097] Table 1 Catalyst

[0098] catalyst Hydroprocessing catalyst Hydrodecondensation catalyst Supplementary refining catalyst Appearance Shamrock Shamrock Shamrock <![CDATA[Pore volume / (cm 3 ·g -1 )]]> ＞0.30 ＞0.18 ＞0.35 <![CDATA[Specific surface area / (m 2 ·g -1 )]]> ＞200 ＞180 ＞150 <![CDATA[Bulk density / (g·cm -3 )]]> 0.75-0.90 0.70-0.80 0.82-0.88 Diameter / mm 1.3-1.6 1.3-1.6 1.0-1.4 <![CDATA[Crushing strength / (N·mm -1 )]]> ＞10.0 ＞10.0 ＞15.0 <![CDATA[Mass fraction of WO3 / %]]> 25.7 - 22.3 NiO mass fraction / % 3.6 2.0 4.6 <![CDATA[Mass fraction of MoO3 / %]]> - - 7.5

[0099] Example 1

[0100] A method for producing transformer oil base oil and transformer oil from cycloalkane distillate oil comprises the following steps:

[0101] The naphthenic second-line distillate oil produced by a refinery was used as the raw material oil, and the properties of the raw material oil are shown in Table 2;

[0102] The crude oil is mixed with hydrogen and then passed through the hydrotreating catalyst of the first hydrogenation reactor, the hydrodecondensation catalyst of the second hydrogenation reactor, and the supplementary refining catalyst in sequence. The feed volume space velocity is 1.0h -1 , hydrogen-oil volume ratio is 600:1, and the system hydrogen partial pressure is 9.5MPa;

[0103] Among them, the loading volume ratio of the three catalysts of hydrotreating, hydrodecondensation and supplementary refining is 3:1:2, and the average reaction temperatures of the three catalysts are 350℃, 345℃ and 355℃ respectively;

[0104] The product obtained from the above reaction, i.e., the refined product oil, is subjected to gas-liquid separation and fractionation, and the side line of the vacuum tower at 300°C-325°C is taken out to obtain the UHV transformer oil base oil, and the side line product of the vacuum tower at 275°C-300°C is mixed with the bottom product of the vacuum tower above 325°C according to the side line yield to obtain the Class I transformer oil base oil; the base oil product analysis data is shown in Table 3;

[0105] The obtained UHV transformer oil base oil is added with 2,6-di-tert-butyl-p-cresol (antioxidant) to obtain UHV transformer oil; the obtained Class I transformer oil base oil is added with 2,6-di-tert-butyl-p-cresol (antioxidant) to obtain Class I transformer oil; the transformer oil product analysis data is shown in Table 4.

[0106] Example 2

[0107] A method for producing transformer oil base oil and transformer oil from cycloalkane distillate oil comprises the following steps:

[0108] The mixed oil of naphthenic regular second-line distillate oil and naphthenic reduced first-line distillate oil produced by a refinery in a mass ratio of 1:1 was used as the raw material oil. The properties of the raw material oil are shown in Table 2.

[0109] The crude oil is mixed with hydrogen and then passed through the hydrotreating catalyst of the first hydrogenation reactor, the hydrodecondensation catalyst of the second hydrogenation reactor, and the supplementary refining catalyst in sequence. The feed volume space velocity is 1.0h -1 , hydrogen-oil volume ratio is 600:1, and the system hydrogen partial pressure is 9.5MPa;

[0110] Among them, the loading volume ratio of the three catalysts of hydrotreating, hydrodecondensation and supplementary refining is 3:1:2, and the average reaction temperatures of the three catalysts are 355℃, 350℃ and 360℃ respectively;

[0111] The product obtained from the above reaction, i.e., the refined product oil, is subjected to gas-liquid separation and fractionation, and the side line of the vacuum tower at 300°C-325°C is taken out to obtain the UHV transformer oil base oil, and the side line product of the vacuum tower at 275°C-300°C is mixed with the bottom product of the vacuum tower above 325°C according to the side line yield to obtain the Class I transformer oil base oil; the base oil product analysis data is shown in Table 3;

[0112] The obtained UHV transformer oil base oil is added with 2,6-di-tert-butyl-p-cresol (antioxidant) to obtain UHV transformer oil; the obtained Class I transformer oil base oil is added with 2,6-di-tert-butyl-p-cresol (antioxidant) to obtain Class I transformer oil; the transformer oil product analysis data is shown in Table 4.

[0113] Table 2 Crude oil

[0114] Crude oil Example 1 Example 2 <![CDATA[Density (20 °C), g / cm 3 > 0.9084 0.9171 Sulfur content / ppm 2290 2650 Nitrogen content / ppm 510 532 Closed cup flash point / ℃ 141.0 132.0 Pour point / ℃ -27.0 -33.0 CA value / % 18.2 20.5 Distillation range / ℃ 275-362 263-372 Mass spectrum composition, % Alkanes 12.3 10.6 Cycloalkanes 63.8 63.3 Aromatics 36.2 36.7 The pour point of fractions above 280℃, ℃ -3 -6

[0115] Table 3 Transformer oil base oil products

[0116]

[0117] Table 4 Transformer oil products

[0118]

[0119] Test Example 1

[0120] The experiment was carried out with the same raw materials, process flow and operating conditions as in Example 1. The device was operated continuously for 120 days, and the UHV transformer oil was sampled and analyzed for aromatic content and pour point every 48 hours. The periodic data were shown in Table 5.

[0121] Table 5 Stability of transformer oil aromatics and pour point

[0122]

[0123] As shown in Table 5, the transformer oil base oil obtained by the present invention has an average pour point of -57°C and an aromatic content of 9%-10% within a 300h-2900h operating cycle, has the advantages of low pour point and low aromatic content, has stable properties, and is a high-quality transformer oil base oil product.

[0124] Test Example 2

[0125] The main factor restricting the long-term operation of industrial equipment is the rapid increase in the pressure drop of the equipment. In addition to the raw material factor, the growth rate of the pressure drop is also directly related to the porosity of the catalyst itself, the permeability of the bed, and the quality of logistics distribution. The hydrogenation catalyst has a high porosity and good permeability, which is conducive to the diffusion of reactants and products, reduces the pressure drop of the decondensation catalyst bed, and is beneficial to the long-term operation of the equipment.

[0126] In order to verify the stability of the catalyst in the production method of the present invention and facilitate the long-term operation of the device, the catalyst stability was tested on a medium-sized hydrogenation test device with a process flow similar to that of an industrial device.

[0127] The experiment was carried out using Example 1 and Example 2. The device was operated continuously for 2600 hours. The static pressure drop at the inlet a of the first hydrogenation reactor R1 and the outlet b of the second hydrogenation reactor R2 was measured at the 300th hour and the 2600th hour. The periodic data were shown in Table 6.

[0128] Table 6 Reactor pressure drop

[0129]

[0130] It can be seen from Table 6 that after the device has been running continuously for 2600 hours, the total pressure drop has increased by 0.02 MPa compared with 300 hours, which fully meets the index requirements of the industrial device. It can be seen that the three hydrogenation catalysts used in the present invention are conducive to the diffusion of reactants and products, can reduce the pressure drop of the catalyst bed, and are conducive to the long-term operation of the device.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing transformer oil base oil from cycloalkane distillate oil, characterized in that: The following steps are involved: (a) subjecting the naphthenic distillate oil to a hydrogenation treatment, a hydrodecondensation treatment and a refining treatment in sequence under a reaction pressure of not more than 10.0 MPa to obtain a refined product oil; (b) fractionating the refined product oil in a vacuum tower, extracting a side line at 300° C.-325° C. of the vacuum tower to obtain a UHV transformer oil base oil, and mixing a side line product at 275° C.-300° C. of the vacuum tower with a bottom product at above 325° C. of the vacuum tower according to a side line yield to obtain a Class I transformer oil base oil.

2. The method according to claim 1, characterized in that The reaction pressure is 8.0MPa-10.0MPa.

3. The method according to claim 1 or 2, characterized in that: The naphthenic distillate oil comprises at least one of naphthenic normal second-line distillate oil and naphthenic minus first-line distillate oil; Preferably, the cycloalkane distillate oil is a cycloalkane normal second-line distillate oil.

4. The method according to claim 1, characterized in that: The reaction temperature of the hydrotreatment is 300°C-370°C; Preferably, the volume ratio of hydrogen to cycloalkyl distillate oil in the hydroprocessing is (600-1200):

1.

5. The method according to claim 1, characterized in that The reaction temperature of the hydrodecondensation treatment is 280°C-340°C; Preferably, the volume ratio of hydrogen in the hydrodecondensation treatment to the generated oil obtained by the hydrotreatment is (600-1200):

1.

6. The method according to claim 1, characterized in that The reaction temperature of the refining treatment is 290°C-360°C; Preferably, the volume ratio of hydrogen in the refining treatment to the product oil obtained by the hydrodecondensation treatment is (600-1200):

1.

7. A UHV transformer oil base oil, characterized in that: Prepared by the method according to any one of claims 1 to 6; Preferably, the sulfur content of the UHV transformer oil base oil is less than 1.0 mg / kg, the nitrogen content is less than 1.0 mg / kg, and the total aromatics is less than 10%; Preferably, the pour point of the UHV transformer oil base oil is less than -57°C, and the kinematic viscosity at 40°C is less than 8.0 mm 2 / s, closed cup flash point>140℃.

8. A UHV transformer oil, characterized in that: Comprising the UHV transformer oil base oil and an antioxidant as claimed in claim 7; Preferably, the added weight percentage of the antioxidant is 0.3%±0.05%; Preferably, the aniline point of the UHV transformer oil is 72°C-78°C, the oxidation stability at 120°C for 500h, the total acid value is <0.08mgKOH / g, and the sludge is <0.004%.

9. A Class I transformer oil base oil, characterized in that: Prepared by the method according to any one of claims 1 to 6; Preferably, the sulfur content of the Class I transformer oil base oil is less than 1.0 mg / kg, the nitrogen content is less than 1.0 mg / kg, and the total aromatics is less than 10%; Preferably, the pour point of the Class I transformer oil base oil is less than -57°C, and the kinematic viscosity at 40°C is less than 12.0 mm 2 / s, closed cup flash point>140℃.

10. A Class I transformer oil, characterized in that: Comprising the Class I transformer oil base oil of claim 9 and an antioxidant; Preferably, the added weight percentage of the antioxidant is 0.3%±0.05%; Preferably, the Class I transformer oil has an oxidation stability at 120° C. for 500 h, a total acid value of <0.17 mgKOH / g, and oil sludge of <0.0056%.

Images