Insulating oil and preparation method thereof

Abstract

The invention discloses insulating oil and a preparation method thereof. The insulating oil comprises base oil and a water removal agent, and the water removal agent comprises at least one of an isocyanate water removal agent, a silane water removal agent, an oxazolidine water removal agent, an ester water removal agent and a nitrile water removal agent. The insulating oil provided by the invention is low in moisture content, long in service life and high in insulating property.

Description

Technical Field

[0001] The invention relates to the technical field of industrial oils, and in particular to insulating oil and a preparation method thereof. Background Art

[0002] Insulating oil is an important insulating material for most power equipment. It plays the role of insulation and heat dissipation and is known as the "blood" for the safe operation of power equipment.

[0003] Commonly used insulating oils are divided into two categories, one is non-flammable oil and the other is flame-retardant oil. Among them, non-flammable oil uses silicone oil, synthetic ester, natural ester and their complexes with high flash point as the main components. Due to the high flash point of the above substances, they have a certain degree of safety. Flame-retardant oil is achieved by further introducing flame retardants on the basis of traditional mineral oil, fluorinated liquid, silicone oil, synthetic ester, natural ester and their complexes. However, whether it is flame-retardant oil or non-flammable oil, during the application process, its bulk phase contains trace amounts of conductive moisture, which greatly affects its insulation performance. In addition, the presence of moisture will also slowly hydrolyze the insulating oil and flame retardant, ultimately affecting their service life and bringing huge safety hazards.

[0004] At present, the traditional method of removing water from insulating oil is through vacuum filtration, which is costly and energy-intensive. Moreover, after water removal, new trace amounts of water will inevitably dissolve into the insulating oil system during long-term use, and the water removal effect is not sustainable. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, one object of the present invention is to provide an insulating oil and a preparation method thereof. The insulating oil provided by the present application has a low moisture content, a long service life and high insulation performance.

[0006] In one aspect of the present invention, the present invention provides an insulating oil. According to an embodiment of the present invention, the insulating oil includes a base oil and a dehydrating agent, and the dehydrating agent includes at least one of an isocyanate dehydrating agent, a silane dehydrating agent, an oxazolidine dehydrating agent, an ester dehydrating agent, and a nitrile dehydrating agent.

[0007] According to the insulating oil of the above embodiment of the present invention, the base oil, as the main component of the insulating oil, has certain insulating properties and provides basic insulation protection; in addition, the base oil can also provide a medium environment for the dehydrating agent to exist, so that the dehydrating agent can be evenly dissolved therein, so as to better fully contact with the water in the insulating oil and play a dehydrating role. By introducing at least one of isocyanate dehydrating agents, silane dehydrating agents, oxazolidine dehydrating agents, ester dehydrating agents and nitrile dehydrating agents into the insulating oil, it can react chemically or physically adsorb with the water in the insulating oil, thereby removing the water. For example, the isocyanate in the isocyanate dehydrating agent can react with water to remove it from the insulating oil system, thereby reducing the water content in the insulating oil; the silane dehydrating agent contains active groups such as silicon-hydrogen (Si-H) in its molecular structure, which can undergo a hydrolysis reaction with water and can fix water molecules in the form of chemical bonds, thereby achieving the purpose of dehydration, and so on. Therefore, the addition of the dehydrating agent is like a "moisture guard" that can continuously remove the moisture that enters the insulating oil, continuously eliminate the trace moisture inside the insulating oil, and avoid the occurrence of safety hazards caused by the existence of hydrolysis reactions, thereby ensuring the stability of the insulation performance and improving the service life of the insulating oil, thereby ensuring the long service life and high insulation performance of the insulating oil. Therefore, the insulating oil provided by the present application has a low moisture content, a long service life, and high insulation performance.

[0008] In addition, the insulating oil according to the above embodiment of the present invention may also have the following additional technical features:

[0009] In some embodiments of the present invention, the mass of the dehydrating agent accounts for 0.01%-2% of the mass of the base oil. Thus, by limiting the content of the dehydrating agent within the above range, it is ensured that there is enough dehydrating agent to remove the moisture in the insulating oil, thereby achieving long-term removal of moisture in the insulating oil and ensuring the operation of the insulating oil with long service life and high insulation performance.

[0010] In some embodiments of the present invention, the isocyanate dehydrating agent includes at least one of trimethylsilyl isocyanate and p-toluenesulfonyl isocyanate. Thus, the above dehydrating agent can be used to continuously and effectively remove moisture from the insulating oil, ensuring the long life and high insulation performance of the insulating oil.

[0011] In some embodiments of the present invention, the silane dehydrating agent includes at least one of vinyl trimethoxy silane, heptamethyl disilazane and vinyl triethoxy silane. Thus, the above dehydrating agent can be used to continuously and effectively remove moisture from the insulating oil, ensuring the long life and high insulation performance of the insulating oil.

[0012] In some embodiments of the present invention, the oxazolidine dehydrating agent includes at least one of 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine, 3-butyl-2-(1-ethylpentyl)oxazolidine, 3-butyl-2-(1-ethylpentyl)oxazolidine and 2-isopropyl-3-oxazolidine ethanol. Therefore, the above dehydrating agent can be used to continuously and effectively remove moisture from the insulating oil, ensuring the long life and high insulation performance of the insulating oil.

[0013] In some embodiments of the present invention, the ester dehydrating agent includes at least one of bis(trichloromethyl) carbonate, triethyl orthoformate and propylene glycol monomethyl ether acetate. Thus, the above dehydrating agent can be used to continuously and effectively remove moisture from the insulating oil, ensuring the long life and high insulation performance of the insulating oil.

[0014] In some embodiments of the present invention, the nitrile dehydrating agent includes at least one of hexane trinitrile, adiponitrile and 1,3,5-pentane trinitrile. Therefore, the above dehydrating agent can be used to continuously and effectively remove moisture from the insulating oil, ensuring the long life and high insulation performance of the insulating oil.

[0015] In some embodiments of the present invention, the base oil includes at least one of mineral oil, silicone oil, synthetic ester, natural ester, fluorinated liquid and flame retardant oil. Thus, the base oil can improve the flame retardant property of the insulating oil.

[0016] In some embodiments of the present invention, the mineral oil includes at least one of a paraffin-based oil and a naphthenic oil.

[0017] In some embodiments of the present invention, the mineral oil includes at least one of No. 10 mineral oil, No. 25 mineral oil and No. 45 mineral oil.

[0018] In some embodiments of the present invention, the silicone oil includes at least one of methyl silicone oil and methyl silicone oil-modified silicone oil.

[0019] In some embodiments of the present invention, the silicone oil includes at least one of dimethyl silicone oil, methylphenyl silicone oil, methylethoxy silicone oil, methyltrifluoropropyl silicone oil and methylvinyl silicone oil.

[0020] In some embodiments of the present invention, the synthetic ester includes phosphate ester, fatty acid ester, such as at least one of trioctyl phosphate, tributyl phosphate, trimethylolpropane trioleate and pentaerythritol tetraoleate.

[0021] In some embodiments of the present invention, the natural ester comprises a vegetable oil.

[0022] In some embodiments of the present invention, the natural ester includes at least one of olive oil, peanut oil, soybean oil, corn oil, sunflower oil and palm oil.

[0023] In some embodiments of the present invention, the fluorinated liquid includes at least one of a perfluorinated compound and a hydrofluoroether.

[0024] In some embodiments of the present invention, the fluorinated liquid includes at least one of perfluorotriethylamine, perfluorotripropylamine, perfluorooctane, perfluoroheptane, methyl nonafluorobutyl ether and ethyl nonafluorobutyl ether.

[0025] In some embodiments of the present invention, the flame retardant oil includes a flame retardant, so that the safety performance of the insulating oil can be improved by adding the flame retardant.

[0026] In some embodiments of the present invention, the flame retardant includes halogenated hydrocarbons, and the halogen element in the halogenated hydrocarbons includes at least one of fluorine, chlorine, bromine and iodine.

[0027] In some embodiments of the present invention, the halogenated hydrocarbon includes at least one of tetrachloroethylene, tetrachloroethane, tetrabromoethane, tetrabromoethylene, hexachloroethane, dibromotetrafluoroethane, dibromotetrachloroethane, tribromotrifluoroethane, 1,2-dibromo-1-chloro-1,2,2-trifluoroethane, dibromohexafluoropropane, trichloropentafluoropropane, hexachloroacetone, hexachloropropylene, hexachlorobutadiene, dibromooctafluorobutane, dibromohexafluorocyclobutane, dichlorooctafluorobutane, dichlorohexafluorocyclobutane, diiodoperfluorobutane and dibromoperfluorohexane.

[0028] In a second aspect of the present invention, the present invention provides a method for preparing the above insulating oil. According to an embodiment of the present invention, the method comprises: mixing a base oil and a dehydrating agent to obtain insulating oil, wherein the dehydrating agent comprises at least one of an isocyanate dehydrating agent, a silane dehydrating agent, an oxazolidine dehydrating agent, an ester dehydrating agent and a nitrile dehydrating agent. Thus, the method is simple, and the obtained insulating oil has a low moisture content, and the insulating oil has a long service life and high insulation performance.

[0029] In some embodiments of the present invention, the mixing temperature is 25°C-60°C.

[0030] In some embodiments of the present invention, the mixing speed is 600 r / min-1000 r / min.

[0031] In some embodiments of the present invention, the mixing time is 10h-20h.

[0032] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. DETAILED DESCRIPTION

[0033] Embodiments of the present invention are described in detail below. The embodiments described below are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0034] In one aspect of the present invention, the present invention provides an insulating oil. According to an embodiment of the present invention, the insulating oil includes a base oil and a dehydrating agent, and the dehydrating agent includes at least one of an isocyanate dehydrating agent, a silane dehydrating agent, an oxazolidine dehydrating agent, an ester dehydrating agent, and a nitrile dehydrating agent.

[0035] According to the insulating oil of the above embodiment of the present invention, the base oil, as the main component of the insulating oil, has certain insulating properties and provides basic insulation protection; in addition, the base oil can also provide a medium environment for the dehydrating agent to exist, so that the dehydrating agent can be evenly dissolved therein, so as to better fully contact with the water in the insulating oil and play a dehydrating role. By introducing at least one of isocyanate dehydrating agents, silane dehydrating agents, oxazolidine dehydrating agents, ester dehydrating agents and nitrile dehydrating agents into the insulating oil, it can react chemically or physically adsorb with the water in the insulating oil, thereby removing the water. For example, the isocyanate in the isocyanate dehydrating agent can react with water to remove it from the insulating oil system, thereby reducing the water content in the insulating oil; the silane dehydrating agent contains active groups such as silicon-hydrogen (Si-H) in its molecular structure, which can undergo a hydrolysis reaction with water and can fix water molecules in the form of chemical bonds, thereby achieving the purpose of dehydration, and so on. Therefore, the addition of the dehydrating agent is like a "moisture guard" that can continuously remove the moisture that enters the insulating oil, continuously eliminate the trace moisture inside the insulating oil, and avoid the occurrence of safety hazards caused by the existence of hydrolysis reactions, thereby ensuring the stability of the insulation performance and improving the service life of the insulating oil, thereby ensuring the long service life and high insulation performance of the insulating oil. Therefore, the insulating oil provided by the present application has a low moisture content, a long service life, and high insulation performance.

[0036] According to some embodiments of the present invention, the mass of the dehydrating agent accounts for 0.01%-2% of the mass of the base oil. For example, it can be 0.01%, 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, etc. By limiting the content of the dehydrating agent within the above range, it is possible to ensure that there is enough dehydrating agent to remove the moisture in the insulating oil. If the content of the dehydrating agent is too low, it is impossible to effectively deal with the moisture gradually absorbed by the insulating oil during operation. For example, in an electric power equipment that is in a high humidity environment for a long time, a small amount of dehydrating agent will be quickly consumed and cannot continue to play a dehydrating role, resulting in a gradual increase in the water content in the insulating oil, thereby affecting its insulation performance and service life. If the content of the dehydrating agent is too high, too much dehydrating agent will change the basic physical and chemical properties of the insulating oil, thereby affecting the stability of the insulating oil. Therefore, by limiting the content of the dehydrating agent within the above range, it is ensured that there is enough dehydrating agent to remove the moisture in the insulating oil, thereby achieving long-term removal of moisture in the insulating oil and ensuring the operation of the insulating oil with long life and high insulation performance.

[0037] According to some embodiments of the present invention, the isocyanate dehydrating agent includes at least one of trimethylsilyl isocyanate and p-toluenesulfonyl isocyanate. The above-mentioned isocyanate dehydrating agent can react chemically with water molecules in the insulating oil to convert water into other compounds, thereby removing moisture. Among them, trimethylsilyl isocyanate (TMS-NCO) has high reactivity and can react quickly with moisture in the insulating oil. It can remove newly entered moisture in the insulating oil in time, which helps to achieve long-term removal of moisture in the insulating oil. Moreover, the products generated by the reaction, such as trimethylsilylamine, have good stability in the insulating oil, thereby ensuring the long-life operation of the insulating oil. Since trimethylsilyl isocyanate can effectively remove moisture, and water is one of the main factors that reduce the insulating performance of the insulating oil, it can maintain the high insulating performance of the insulating oil. Toluenesulfonyl isocyanate can selectively react with water in insulating oil. The isocyanate group (-NCO) in its chemical structure has a strong affinity for water and can accurately remove moisture from insulating oil without reacting unnecessarily with other main components in insulating oil, which helps to maintain the chemical stability of insulating oil for a long time. Therefore, the above-mentioned dehydrating agent can continuously and effectively remove moisture from insulating oil, ensuring the long life and high insulation performance of insulating oil.

[0038] According to some embodiments of the present invention, the silane dewatering agent includes at least one of vinyl trimethoxysilane, heptamethyl disilazane and vinyl triethoxysilane. The molecular structure of the silane dewatering agent contains active groups that can react with water, such as methoxy (-OCH3) active groups in vinyl trimethoxysilane molecules, silicon-nitrogen (Si-N) structure active groups in heptamethyl disilazane molecules, and ethoxy (-OC2H5) active groups in vinyl triethoxysilane molecules. These active groups can be hydrolyzed to generate silanols first, and then silanols are condensed to combine water molecules into the silane structure, which can effectively remove moisture from the insulating oil and can play a role for a long time. It can continuously absorb and process the moisture entering the insulating oil to ensure that the water content is always at a low level, thereby maintaining the chemical stability of the insulating oil and preventing the aging of the insulating oil caused by moisture, thereby extending the life of the insulating oil. In addition, by selecting the above-mentioned dewatering agent, moisture can be effectively removed and the high insulation performance of the insulating oil can be maintained. Therefore, the above-mentioned dehydrating agent can be used to continuously and effectively remove moisture from the insulating oil, ensuring the long service life and high insulation performance of the insulating oil.

[0039] According to some embodiments of the present invention, the oxazolidine dehydrating agent includes at least one of 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine, 3-butyl-2-(1-ethylpentyl)oxazolidine, 3-butyl-2-(1-ethylpentyl)oxazolidine and 2-isopropyl-3-oxazolidine ethanol. Oxazolidine compounds are dehydrating agents with a cyclic structure, which can undergo a ring-opening reaction with water in insulating oil, bind water molecules to the molecular structure, and can effectively bind water molecules in insulating oil and fix them in the newly formed compound structure. The above-selected oxazolidine dehydrating agent can bind to water through a ring-opening reaction. Its reactivity enables it to react quickly with the moisture in the insulating oil and effectively remove moisture. During the long-term operation of the insulating oil, this oxazolidine can continue to play a role and maintain the low water content of the insulating oil. Moreover, the product formed after the above dehydrating agent reacts with water has good stability in the insulating oil, does not cause chemical changes in the insulating oil, such as oxidation and hydrolysis, etc., can prevent the insulating oil from aging, reduce the generation of acidic substances, and thus extend the service life of the insulating oil. In addition, by removing moisture, it helps to maintain the high dielectric strength and low dielectric loss factor of the insulating oil, ensuring its high insulation performance in a high voltage environment. Therefore, the use of the above dehydrating agent can continuously and effectively remove moisture from the insulating oil, ensuring the long life and high insulation performance of the insulating oil.

[0040] According to some embodiments of the present invention, the ester dehydrating agent includes at least one of bis(trichloromethyl) carbonate, triethyl orthoformate and propylene glycol monomethyl ether acetate. By selecting the above-mentioned ester dehydrating agent, the moisture in the insulating oil can be continuously and effectively removed. Among them, the carbonyl group (C=O) in the bis(trichloromethyl) carbonate (BTC) molecule is a polar group. In the insulating oil, it can form hydrogen bonds with water molecules. When there is water in the insulating oil, BTC can wrap the water molecules around its molecules through hydrogen bonding, so that the water molecules are dispersed in the insulating oil, avoiding the aggregation of water molecules. Moreover, as long as there is water in the insulating oil, this interaction will continue, thereby achieving long-term removal of water in the insulating oil. The ethoxy group in the molecular structure of triethyl orthoformate (TFE) can react with water molecules to generate ethanol and ethyl formate, which can effectively remove moisture from the insulating oil. During the long-term operation of the insulating oil, as long as there is enough triethyl orthoformate, the moisture entering the insulating oil can be continuously removed. The ester polar group in propylene glycol monomethyl ether acetate (PMA) can form hydrogen bonds with water. In insulating oil, it wraps water molecules around the molecules through this hydrogen bonding effect, so that the water is evenly dispersed in the insulating oil, and the water in the insulating oil can be removed for a long time, because as long as there is water, the hydrogen bond formation process will continue. The product of the above-mentioned dehydrating agent after dehydration has a certain stability in the insulating oil, and will not cause harmful reactions such as oxidation and hydrolysis of the insulating oil like water, thereby maintaining the chemical stability of the insulating oil and helping to extend the service life of the insulating oil. Water will reduce the insulating performance of the insulating oil. The above-mentioned dehydrating agent helps to maintain the high dielectric strength and low dielectric loss factor of the insulating oil by removing water, ensuring its high insulation performance in a high voltage environment. Therefore, the selection of the above-mentioned dehydrating agent can continuously and effectively remove the water in the insulating oil, ensuring the long life and high insulation performance of the insulating oil.

[0041] According to some embodiments of the present invention, the nitrile dehydrating agent includes at least one of hexane trinitrile, adiponitrile and 1,3,5-pentane trinitrile. The nitrile group (-CN) in the nitrile dehydrating agent is a strong polar group that can interact with water and adsorb water molecules on the surface of the nitrile molecule. For example, the hexane trinitrile molecule contains three nitrile groups (-CN), the adiponitrile molecule has two nitrile groups, and 1,3,5-pentane trinitrile contains three nitrile groups. In the insulating oil, these nitrile groups can interact with water molecules, adsorb water molecules through hydrogen bonds or dipole-dipole interactions, and gather water molecules on the surface of the nitrile dehydrating agent molecules. As long as there is water in the insulating oil, this adsorption process will continue, thereby achieving long-term removal of water, helping to maintain the high dielectric strength and low dielectric loss factor of the insulating oil, and ensuring its high insulation performance in a high voltage environment. In addition, the above dehydrating agent will not cause oxidation and hydrolysis of the insulating oil like water during the dehydration process, and can maintain the chemical stability of the insulating oil, prevent aging of the insulating oil and equipment corrosion caused by water, thereby extending the service life of the insulating oil. Therefore, the above dehydrating agent can continuously and effectively remove moisture from the insulating oil, ensuring the long service life and high insulation performance of the insulating oil.

[0042] According to some embodiments of the present invention, the base oil includes at least one of mineral oil, silicone oil, synthetic ester, natural ester, fluorinated liquid and flame retardant oil. The above base oil is selected, on the one hand, the chemical bonds and electron distribution in its molecular structure make it have the characteristics of preventing current conduction. For example, mineral oil is mainly composed of hydrocarbons, and these non-polar molecules can effectively prevent the movement of electrons, thereby playing an insulating role in electrical equipment. On the other hand, the above base oil also has a certain thermal conductivity, which can transfer the heat generated during the operation of the electrical equipment. Taking mineral oil as an example, when the transformer is working, the winding and the iron core will generate heat. After the mineral oil absorbs this heat, it transfers the heat to the outer shell of the equipment through natural convection or forced convection (such as in some equipment with cooling devices), and then dissipates it to the surrounding environment, which can effectively prevent the internal temperature of the equipment from being too high, and protect the insulation performance of the equipment and the normal operation of other components. Finally, the above base oil can also resist oxidation and hydrolysis reactions to a certain extent, thereby extending the service life of the insulating oil. Therefore, the above base oil can improve the flame retardant properties of the insulating oil.

[0043] As an example, the mineral oil includes but is not limited to at least one of paraffin-based oil and naphthenic oil. The mineral oil is at least one of No. 10 mineral oil, No. 25 mineral oil and No. 45 mineral oil.

[0044] As an example, the silicone oil includes but is not limited to at least one of methyl silicone oil and methyl silicone modified silicone oil, and the silicone oil is at least one of dimethyl silicone oil, methylphenyl silicone oil, methylethoxy silicone oil, methyltrifluoropropyl silicone oil and methylvinyl silicone oil.

[0045] As an example, the synthetic ester includes, but is not limited to, phosphate ester, fatty acid ester, such as at least one of trioctyl phosphate, tributyl phosphate, trimethylolpropane trioleate, and pentaerythritol tetraoleate.

[0046] As an example, the natural ester includes, but is not limited to, vegetable oils, such as at least one of olive oil, peanut oil, soybean oil, corn oil, sunflower oil, and palm oil.

[0047] As an example, the fluorinated liquid includes but is not limited to at least one of a perfluorinated compound and a hydrofluoroether, such as at least one of perfluorotriethylamine, perfluorotripropylamine, perfluorooctane, perfluoroheptane, methyl nonafluorobutyl ether and ethyl nonafluorobutyl ether.

[0048] According to some embodiments of the present invention, the flame retardant oil includes a flame retardant. The flame retardant in the flame retardant oil can play a role in fire prevention. When encountering a fire source, the flame retardant can prevent the spread of the flame. For example, some flame retardants will decompose and produce non-flammable gases such as carbon dioxide, ammonia, etc. when heated. These gases can dilute the oxygen concentration in the surrounding air, thereby inhibiting the combustion reaction. In addition, some flame retardants can form a dense carbon layer on the surface of the material. This carbon layer can isolate oxygen and prevent heat transfer, and play a role in heat insulation and oxygen isolation, just like setting a barrier for the flame, effectively preventing the further spread of the flame, thereby improving the safety performance of the insulating oil. Therefore, the addition of flame retardants can improve the safety performance of the insulating oil.

[0049] As an example, the flame retardant includes halogenated hydrocarbons, and the halogen element in the halogenated hydrocarbons includes at least one of fluorine, chlorine, bromine, and iodine.

[0050] As an example, the halogenated hydrocarbon includes at least one of tetrachloroethylene, tetrachloroethane, tetrabromoethane, tetrabromoethylene, hexachloroethane, dibromotetrafluoroethane, dibromotetrachloroethane, tribromotrifluoroethane, 1,2-dibromo-1-chloro-1,2,2-trifluoroethane, dibromohexafluoropropane, trichloropentafluoropropane, hexachloroacetone, hexachloropropylene, hexachlorobutadiene, dibromooctafluorobutane, dibromohexafluorocyclobutane, dichlorooctafluorobutane, dichlorohexafluorocyclobutane, diiodoperfluorobutane and dibromoperfluorohexane.

[0051] In the second aspect of the present invention, the present invention proposes a method for preparing the above-mentioned insulating oil. According to an embodiment of the present invention, the method comprises: mixing a base oil and a dehydrating agent to obtain insulating oil, wherein the dehydrating agent comprises at least one of an isocyanate dehydrating agent, a silane dehydrating agent, an oxazolidine dehydrating agent, an ester dehydrating agent and a nitrile dehydrating agent. Therefore, the method provided by the present application is simple, and the obtained insulating oil has a low moisture content, and the insulating oil has a long service life and high insulation performance. It should be noted that the above-mentioned features and advantages described for insulating oil are also applicable to the preparation method of insulating oil, which will not be repeated here.

[0052] According to some embodiments of the present invention, the mixing temperature is 25°C-60°C. For example, it can be 25°C, 30°C, 40°C, 50°C, 60°C, etc. By limiting the mixing temperature within the above range, the molecular motion of the base oil and the dehydrating agent is more active, which is conducive to better dissolution of the dehydrating agent in the base oil, and helps to improve the dispersion effect of the dehydrating agent in the insulating oil, so as to better play the dehydrating function.

[0053] According to some embodiments of the present invention, the mixing speed is 600r / min-1000r / min. For example, it can be 600r / min, 700r / min, 800r / min, 900r / min, 1000r / min, etc. By limiting the mixing speed within the above range, it is possible to promote more complete contact between the molecules of the base oil and the dehydrating agent, and the shear force and convection generated during the mixing process can make the molecules of the dehydrating agent quickly dispersed in the base oil, and the molecules can be evenly distributed in various parts of the base oil, avoiding the situation where the local concentration is too high or too low, which helps to ensure that the insulating oil in each micro area can contain an appropriate amount of dehydrating agent, thereby effectively removing moisture.

[0054] It should be noted that there is no particular limitation on the mixing method. According to a specific embodiment of the present invention, the mixing method includes stirring.

[0055] According to some embodiments of the present invention, the mixing time is 10 hours to 20 hours. For example, it can be 10 hours, 12 hours, 15 hours, 17 hours, 20 hours, etc. By limiting the mixing time to the above range, sufficient time can be given to the base oil and the water remover to allow the base oil and the water remover to be fully mixed at the molecular level, thereby effectively removing moisture.

[0056] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used that do not specify the manufacturer are all conventional products that can be obtained commercially.

[0057] Example 1

[0058] Preparation of insulating oil: 10 parts of No. 25 mineral oil, 90 parts of hexachloropropylene, and 0.5 parts of hexanetrinitrile were weighed and mixed, and stirred at 45° C. and 800 r / min for 12 hours to obtain insulating oil.

[0059] Example 2

[0060] Preparation of insulating oil: Weigh 50 parts of dimethyl silicone oil, 50 parts of dibromooctafluorobutane and 1 part of vinyltrimethoxysilane, mix them, and stir them at 45° C. and 800 r / min for 12 hours to obtain insulating oil.

[0061] Example 3

[0062] Preparation of insulating oil: 80 parts of No. 25 mineral oil, 20 parts of hexachloropropylene, and 0.1 parts of trimethylsilyl isocyanate were weighed and blended, and stirred and mixed at a temperature of 45° C. and a stirring speed of 800 r / min for 12 hours to obtain insulating oil.

[0063] Example 4

[0064] Preparation of insulating oil: 100 parts of No. 25 mineral oil and 0.5 parts of 3-butyl-2-(1-ethylpentyl)oxazolidine were weighed and blended, and stirred at 45° C. and 800 r / min for 12 h to obtain insulating oil.

[0065] Example 5

[0066] Preparation of insulating oil: 100 parts of dimethyl silicone oil and 1 part of bis(trichloromethyl) carbonate were weighed and blended, and stirred at 45° C. and 800 r / min for 12 h to obtain insulating oil.

[0067] Example 6

[0068] Preparation of insulating oil: 10 parts of No. 25 mineral oil, 90 parts of hexachloropropylene, and 0.01 parts of hexanetrinitrile were weighed and mixed, and stirred at 45° C. and 800 r / min for 12 hours to obtain insulating oil.

[0069] Example 7

[0070] Preparation of insulating oil: 10 parts of No. 25 mineral oil, 90 parts of hexachloropropylene and 2 parts of hexanetrinitrile were weighed and mixed, and stirred at 45°C and 800 r / min for 12 hours to obtain insulating oil.

[0071] Comparative Example 1

[0072] Preparation of insulating oil: Weigh 80 parts of No. 25 mineral oil and 20 parts of hexachloropropylene, and stir and mix them at a temperature of 45° C. and a stirring speed of 800 r / min for 12 hours to obtain insulating oil.

[0073] Comparative Example 2

[0074] Preparation of insulating oil: Weigh 100 parts of No. 25 mineral oil, stir and mix at 45°C and 800 r / min for 12 hours, and then vacuum filter to remove water to obtain insulating oil.

[0075] Testing and analysis

[0076] Under the same conditions, the insulating oils prepared in the above Examples 1-7 and Comparative Examples 1-2 were tested for water content, breakdown voltage, and flash point. The specific testing methods are as follows:

[0077] Water content test: According to the method provided in GB / T 7600-2014 "Determination of water content of transformer oil and turbine oil in operation (coulometric method)", the initial water content in the insulating oil and the water content after 30 days of storage are measured respectively.

[0078] Breakdown voltage test: According to the method provided in GB / T 507-2002 "Determination of Breakdown Voltage of Insulating Oil", the initial breakdown voltage in the insulating oil and the breakdown voltage after 30 days of storage are measured respectively.

[0079] Flash point test: According to the method provided in GB / T 261-2021 "Determination of flash point - Pensky-Martin closed cup method", the initial flash point and the flash point after 30 days of storage in the insulating oil are determined respectively.

[0080] The test results are shown in Table 1.

[0081] Table 1

[0082]

[0083] Results and Discussion

[0084] It can be seen from Table 1 that, compared with the insulating oil of Comparative Examples 1-2, the insulating oil of Examples 1-7 has a low moisture content, a long service life and high insulation performance.

[0085] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0086] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An insulating oil, characterized in that: The insulating oil includes base oil and a dehydrating agent, and the dehydrating agent includes at least one of an isocyanate dehydrating agent, a silane dehydrating agent, an oxazolidine dehydrating agent, an ester dehydrating agent and a nitrile dehydrating agent.

2. The insulating oil according to claim 1, characterized in that The mass of the dehydrating agent accounts for 0.01%-2% of the mass of the base oil.

3. The insulating oil according to claim 1 or 2, characterized in that: The isocyanate dehumidifier includes at least one of trimethylsilyl isocyanate and p-toluenesulfonyl isocyanate; And / or, the silane dehumidifier includes at least one of vinyltrimethoxysilane, heptamethyldisilazane and vinyltriethoxysilane.

4. The insulating oil according to claim 1 or 2, characterized in that: The oxazolidine dewatering agent includes at least one of 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine, 3-butyl-2-(1-ethylpentyl)oxazolidine, 3-butyl-2-(1-ethylpentyl)oxazolidine and 2-isopropyl-3-oxazolidine ethanol; And / or, the ester dehydrating agent includes at least one of bis(trichloromethyl) carbonate, triethyl orthoformate and propylene glycol monomethyl ether acetate; And / or, the nitrile dehydrating agent includes at least one of hexanetrinitrile, adiponitrile and 1,3,5-pentanetrinitrile.

5. The insulating oil according to claim 1 or 2, characterized in that: The base oil includes at least one of mineral oil, silicone oil, synthetic ester, natural ester, fluorinated liquid and flame retardant oil.

6. The insulating oil according to claim 5, characterized in that The mineral oil includes at least one of a paraffin-based oil and a naphthenic oil; And / or, the mineral oil includes at least one of No. 10 mineral oil, No. 25 mineral oil and No. 45 mineral oil; And / or, the silicone oil includes at least one of methyl silicone oil and methyl silicone oil-modified silicone oil; And / or, the silicone oil includes at least one of dimethyl silicone oil, methylphenyl silicone oil, methylethoxy silicone oil, methyltrifluoropropyl silicone oil and methylvinyl silicone oil; and / or, the synthetic ester comprises a phosphate ester, a fatty acid ester, such as at least one of trioctyl phosphate, tributyl phosphate, trimethylolpropane trioleate and pentaerythritol tetraoleate; and / or, the natural ester comprises a vegetable oil; and / or, the natural ester comprises at least one of olive oil, peanut oil, soybean oil, corn oil, sunflower oil and palm oil; and or, the fluorinated liquid comprises at least one of a perfluorinated compound and a hydrofluoroether; and / or, the fluorinated liquid comprises at least one of perfluorotriethylamine, perfluorotripropylamine, perfluorooctane, perfluoroheptane, methyl nonafluorobutyl ether and ethyl nonafluorobutyl ether; And / or, the flame retardant oil comprises a flame retardant.

7. The insulating oil according to claim 6, characterized in that The flame retardant includes halogenated hydrocarbons, and the halogen element in the halogenated hydrocarbons includes at least one of fluorine, chlorine, bromine and iodine.

8. The insulating oil according to claim 7, characterized in that The halogenated hydrocarbon includes at least one of tetrachloroethylene, tetrachloroethane, tetrabromoethane, tetrabromoethylene, hexachloroethane, dibromotetrafluoroethane, dibromotetrachloroethane, tribromotrifluoroethane, 1,2-dibromo-1-chloro-1,2,2-trifluoroethane, dibromohexafluoropropane, trichloropentafluoropropane, hexachloroacetone, hexachloropropylene, hexachlorobutadiene, dibromooctafluorobutane, dibromohexafluorocyclobutane, dichlorooctafluorobutane, dichlorohexafluorocyclobutane, diiodoperfluorobutane and dibromoperfluorohexane.

9. A method for preparing the insulating oil according to any one of claims 1 to 8, characterized in that: include: The base oil and the dehydrating agent are mixed to obtain insulating oil, wherein the dehydrating agent includes at least one of an isocyanate dehydrating agent, a silane dehydrating agent, an oxazolidine dehydrating agent, an ester dehydrating agent and a nitrile dehydrating agent.

10. The method according to claim 9, characterized in that The mixing temperature is 25°C-60°C; And / or, the mixing speed is 600r / min-1000r / min; And / or, the mixing time is 10h-20h.

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