CN113817525A - Preparation method of natural ester insulating oil - Google Patents
Preparation method of natural ester insulating oil Download PDFInfo
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- CN113817525A CN113817525A CN202111105878.8A CN202111105878A CN113817525A CN 113817525 A CN113817525 A CN 113817525A CN 202111105878 A CN202111105878 A CN 202111105878A CN 113817525 A CN113817525 A CN 113817525A
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M105/00—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound
- C10M105/08—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound containing oxygen
- C10M105/32—Esters
- C10M105/38—Esters of polyhydroxy compounds
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- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
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- C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
- C10M2207/40—Fatty vegetable or animal oils
- C10M2207/401—Fatty vegetable or animal oils used as base material
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- C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
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- C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
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- C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
- C10N2030/14—Metal deactivation
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- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/14—Electric or magnetic purposes
- C10N2040/16—Dielectric; Insulating oil or insulators
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Abstract
The invention provides a preparation method of natural ester insulating oil, belonging to the field of insulating materials. The invention carries out degumming treatment on raw oil including recovered oil to remove phospholipid so as to reduce the influence of the phospholipid on pour point, is beneficial to promoting the subsequent separation of fatty acid of each component, then carries out ester exchange reaction, obtains mixed fatty acid monoester by removing impurities, then carries out solvent crystallization separation to obtain various high-purity single-component fatty acid monoesters, and then carries out ester exchange reaction with glycerol under the action of a catalystThe corresponding single-component triglyceride with high purity is obtained, and the natural ester insulating oil with low pour point and condensation point, low kinematic viscosity, high fluidity and high heat dissipation capacity can be obtained after mixing. The kinematic viscosity of the natural ester insulating oil prepared by the method is as low as 6mm at 100 DEG C2S, kinematic viscosity at 40 ℃ as low as 30mm2The pour point is as low as-28 ℃, the oxidation resistance is better, and the insulating property is better than that of the traditional natural ester.
Description
Technical Field
The invention relates to the field of insulating materials, in particular to a preparation method of natural ester insulating oil.
Background
The insulating material of the transformer is one of the most important materials in the transformer, and the performance and quality of the insulating material directly affect the reliability of the operation of the transformer and the service life of the transformer. In oil-filled transformers, transformer oil, insulation paper, oil-paper insulation and oil barrier insulation are the main insulation materials in oil-filled transformers. Among all these insulating materials, insulating oil plays a critical role. The insulating oils commonly used today are mainly mineral and vegetable oils.
At present, plant insulating oil (also called natural ester insulating oil) mainly comes from edible oil, such as soybean, rapeseed, almond oil, pricklyash seed oil and the like, and has the technical problem of competing for grains with people. The recovered oil is various inferior oils existing in life, so that the recovered oil contains plant oil, animal oil and other oil types with complex components, and a large amount of saturated fatty acids with high pour points exist in the animal oil, so that the recovered oil is difficult to process into insulating oil.
Disclosure of Invention
The invention aims to provide a preparation method of natural ester insulating oil, which is characterized in that raw oil comprising recovered oil is used as a raw material to prepare the natural ester insulating oil, the requirement on the purity of the raw oil is low, the problem of grain struggle with people is avoided, the prepared natural ester insulating oil has low pour point and condensation point, can be used in low-temperature areas, and has low kinematic viscosity.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of natural ester insulating oil, which comprises the following steps:
(1) degumming raw oil to obtain dephosphorized grease oil, wherein the raw oil comprises recovered oil;
(2) carrying out ester exchange reaction on the dephosphorized fatty oil obtained in the step (1) and alcohol, and then carrying out impurity removal treatment to obtain mixed fatty acid monoester;
(3) carrying out solvent crystallization separation on the mixed fatty acid monoester obtained in the step (2) to obtain various single-component fatty acid monoesters;
(4) performing ester exchange reaction on the single-component fatty acid monoesters obtained in the step (3) and glycerol under the action of a catalyst to obtain single-component triglycerides;
(5) and (4) mixing the single-component triglycerides obtained in the step (4) to obtain the natural ester insulating oil.
Preferably, the degumming treatment in step (1) further comprises a filtration treatment.
Preferably, the degumming treatment in the step (1) comprises acid degumming and hydration degumming which are sequentially carried out.
Preferably, the mass concentration of phospholipids in the dephosphorized fatty oil in the step (1) is less than 60 mg/kg.
Preferably, the alcohol in the step (2) is methanol or ethanol, and the volume of the alcohol is 10-20% of the volume of the phospholipid-removed oil.
Preferably, the temperature of the ester exchange reaction in the step (2) is 50-70 ℃, and the time of the ester exchange reaction is 2-6 h.
Preferably, the impurity removal treatment in the step (2) comprises washing, adsorbing and filtering the product of the transesterification reaction in sequence.
Preferably, the solvent crystallization separation in the step (3) comprises mixing the mixed fatty acid monoester and alcohol, cooling at a speed of 2-5 ℃/min, and filtering to separate various single-component fatty acid monoester solids precipitated in a temperature gradient.
Preferably, the catalyst in step (4) is sodium methoxide or lipase.
Preferably, the mixing of step (5) further comprises adding one or more of an antioxidant, a pour point depressant and a passivating agent.
The invention provides a preparation method of natural ester insulating oil, which comprises the steps of using raw oil comprising recovered oil as a raw material, firstly carrying out degumming treatment to remove phospholipid to obtain dephosphorized fatty oil so as to reduce the influence of the phospholipid on the pour point of the raw oil and simultaneously facilitate the separation of subsequent fatty acids of each component, then carrying out transesterification reaction with alcohol, carrying out impurity removal treatment to obtain mixed fatty acid monoesters, carrying out solvent crystallization separation to obtain various high-purity single-component fatty acid monoesters, then carrying out transesterification reaction with glycerol under the action of a catalyst to obtain various high-purity single-component triglycerides (three fatty acid groups on the glycerol structure of the triglycerides are the same), and mixing the obtained various high-purity single-component triglycerides to obtain the natural ester insulating oil. According to the preparation method provided by the invention, triglyceride contained in the raw oil and alcohol are subjected to ester exchange reaction to obtain the fatty acid monoester which is low in kinematic viscosity and easy to separate (the separation difficulty is far less than that of the triglyceride and the fatty acid), so that the requirement on the purity of the raw oil is greatly reduced, the source of the raw material is expanded, then the raw oil and the glycerol are subjected to ester exchange reaction to obtain the single-component triglyceride with the same high-purity three fatty acid groups, and the natural ester insulating oil prepared by combining the single-component triglyceride with the same high-purity three fatty acid groups has low pour point and condensation point, can be used in low-temperature regions and has low kinematic viscosity. The results of the examples show that the kinematic viscosity at 100 ℃ of the natural ester insulating oil prepared by the process provided herein is as low as 6mm2S, kinematic viscosity at 40 ℃ as low as 30mm2The pour point is as low as minus 28 ℃, the oxidation resistance is better, and the insulating property is better than that of the traditional natural ester.
Detailed Description
The invention provides a preparation method of natural ester insulating oil, which comprises the following steps:
(1) degumming raw oil to obtain dephosphorized grease oil, wherein the raw oil comprises recovered oil;
(2) carrying out ester exchange reaction on the dephosphorized fatty oil obtained in the step (1) and alcohol, and then carrying out impurity removal treatment to obtain mixed fatty acid monoester;
(3) carrying out solvent crystallization separation on the mixed fatty acid monoester obtained in the step (2) to obtain various single-component fatty acid monoesters;
(4) performing ester exchange reaction on the single-component fatty acid monoesters obtained in the step (3) and glycerol under the action of a catalyst to obtain single-component triglycerides;
(5) and (4) mixing the single-component triglycerides obtained in the step (4) to obtain the natural ester insulating oil.
According to the invention, the raw oil is subjected to degumming treatment to obtain the dephosphorized grease oil.
In the present invention, the raw materials used are all commercial products which are conventional in the art, unless otherwise specified.
In the present invention, the raw oil includes a reclaimed oil, and preferably includes a mixed oil composed of a reclaimed oil and a natural crude oil.
Before degumming, the raw oil is preferably filtered to obtain the pretreated oil.
The filtering mode is not particularly limited by the invention, and the technical scheme well known in the field can be adopted. In the application, the filtration treatment can remove suspended impurities, floccules, silt and other solid impurities in the raw oil, and is favorable for the subsequent degumming treatment.
After the pretreated oil material is obtained, the invention carries out degumming treatment on the pretreated oil material.
In the invention, the degumming treatment is preferably acid degumming and hydration degumming which are sequentially carried out. In the invention, the acid degumming is preferably performed by mixing the pretreated oil material and acid, and heating to obtain the acid degummed oil material.
In the present invention, the mixing of the pretreated oil and the acid is preferably performed by adding the acid to the pretreated oil under stirring. The stirring speed is not specially limited, and the components are uniformly mixed. In the present invention, the acid is preferably citric acid, phosphoric acid or acetic acid. In the present invention, the volume of the acid is preferably 1 to 5%, more preferably 1.5 to 3%, and further preferably 2% of the volume of the pretreated oil. In the present invention, the heating temperature is more preferably 40 to 48 ℃, and still more preferably 45 ℃. In the present invention, the non-hydratable phospholipids in the pretreated oil are converted to hydrophilic phospholipids by acid in the acid degumming process.
Obtaining the oil material after acid degumming, preferably carrying out hydration degumming on the oil material after acid degumming to obtain the dephosphorized fat oil.
In the invention, the hydration degumming is preferably to mix the oil material subjected to acid degumming and deionized water, and sequentially stir, stand and separate the mixture to obtain the dephosphorized fat oil. In the invention, the volume of the deionized water is preferably 10-25% of the volume of the pretreated oil material, and more preferably 15-20%. In the present invention, the mixing temperature is preferably 40 to 48 ℃, and more preferably 45 ℃. The stirring speed is not specially limited, and the components are uniformly mixed. In the invention, the standing temperature is preferably 70-90 ℃, and more preferably 80-85 ℃. In the invention, the standing time is preferably 0.5-3 hours, and more preferably 1-2.5 hours. The temperature and the time of standing are controlled within the range, so that the oil phase and the water phase in the system can be effectively layered, and the hydrophilic phospholipid transferred to the water phase can be completely removed in the subsequent liquid separation process. The invention has no special limitation on the liquid separation mode, and the oil phase and the water phase in the system can be effectively separated.
In the invention, the mass concentration of the phospholipid in the dephosphorized fatty oil is less than 60mg/kg, otherwise, the degumming treatment needs to be repeated until the mass concentration of the phospholipid in the dephosphorized fatty oil is less than 60 mg/kg. The invention controls the mass concentration of the phospholipid in the dephosphorized fatty oil within the range, which is beneficial to reducing the influence of the phospholipid on the pour point of the raw oil and simultaneously is beneficial to promoting the separation of the fatty acid of each component subsequently.
After the dephosphorized fatty oil is obtained, the invention preferably carries out ester exchange reaction on the dephosphorized fatty oil and alcohol, and then carries out impurity removal treatment to obtain the mixed fatty acid monoester.
In the present invention, the alcohol is preferably methanol or ethanol. In the present invention, the volume of the alcohol is preferably 10 to 20%, more preferably 13 to 18% of the volume of the dephosphorized fat oil. The present invention controls the kind and volume of the alcohol within the above range, which is advantageous for converting as much as possible of the triglyceride in the dephosphorized fatty oil into fatty acid monoester which is easy to separate.
In the present invention, the acid used in the transesterification reaction is preferably concentrated sulfuric acid with a mass fraction of 98%; the mass of the acid used for the ester exchange reaction is preferably 3-7% of that of the dephosphorized grease oil, and more preferably 4-6%.
In the invention, the temperature of the ester exchange reaction is preferably 50-70 ℃, more preferably 55-65 ℃, and the time of the ester exchange reaction is preferably 2-6 h, more preferably 3-5 h. The present invention controls the temperature and time of the transesterification reaction within the above-mentioned ranges to facilitate the conversion of as much as possible of the triglycerides in the dephosphorized fatty oil into fatty acid monoesters which can be easily separated.
In the present invention, the impurity removal treatment preferably comprises washing, drying, adsorbing and filtering the product of the transesterification reaction in sequence.
In the present invention, the number of washing with water is preferably 2 to 4. In the invention, the temperature of the water washing is preferably 70-90 ℃, and more preferably 75-85 ℃. The present invention controls the temperature and the number of times of washing with water within the above range, and is advantageous in removing water-soluble impurities including metal ions as much as possible.
The drying method is not particularly limited in the present invention, and the moisture removal can be achieved by a technical scheme well known in the art.
In the present invention, the adsorption is preferably performed under stirring conditions. The stirring speed is not specially limited, and the components are uniformly mixed. In the invention, the adsorption temperature is preferably 70-80 ℃, and more preferably 75-85 ℃. In the present invention, the adsorbent used for the adsorption is preferably a mixture of activated carbon and clay. In the present invention, the mass of the activated carbon is preferably 1 to 4%, more preferably 1.5 to 3% of the mass of the product of the transesterification reaction. In the present invention, the clay is preferably 1 to 4% by mass, more preferably 1.5 to 3% by mass, of the product of the transesterification reaction. In the present invention, the adsorption enables decolorization of the product of the transesterification reaction and removal of impurities.
The filtration method is not particularly limited in the present invention, and a method well known in the art may be used. In the present invention, the filter screen used for the filtration is preferably an 800 mesh filter screen.
In the invention, in the impurity removal treatment process, water-soluble impurities including metal ions and other solid impurities in the product of the ester exchange reaction are removed, so that the subsequent solvent crystallization separation is facilitated to obtain various fatty acid monoesters with higher purity.
After obtaining the mixed fatty acid monoester, the invention preferably carries out solvent crystallization separation on the mixed fatty acid monoester to obtain various single-component fatty acid monoesters.
In the invention, the solvent crystallization separation preferably comprises mixing the mixed fatty acid monoester and alcohol, then cooling at the speed of 2-5 ℃/min, and filtering to separate various single-component fatty acid monoester solids precipitated in a temperature gradient. In the present invention, the alcohol is preferably methanol or ethanol. In the present invention, the volume of the alcohol is preferably 10 to 30%, more preferably 15 to 25%, and still more preferably 20% of the volume of the mixed fatty acid monoester. In the invention, the cooling speed is more preferably 2.5-4 ℃/min, and further preferably 3 ℃/min. In the invention, the various single-component fatty acid monoester solids precipitated in the temperature gradient are preferably cooled to 10 ℃ to precipitate methyl stearate and methyl palmitate, cooled to 0 ℃ to precipitate methyl oleate, and cooled to-20 ℃ to precipitate methyl linoleate.
After obtaining various single-component fatty acid monoester solids, the invention preferably distills the various single-component fatty acid monoester solids respectively, removes alcohol solvent, and obtains various single-component fatty acid monoesters. In the invention, the purity of each single-component fatty acid monoester is more than or equal to 90 percent, otherwise, solvent crystallization separation needs to be repeatedly carried out until the purity of each single-component fatty acid monoester is more than or equal to 90 percent. The invention controls the purity of each single-component fatty acid monoester in the range, and is beneficial to the subsequent preparation of the natural ester insulating oil with good insulating property.
After obtaining various single-component fatty acid monoesters, the invention respectively carries out ester exchange reaction on the various single-component fatty acid monoesters and glycerol under the action of a catalyst to obtain various single-component triglycerides.
In the present invention, the ratio of the volume of glycerin to the volume of the corresponding mono-component fatty acid monoester in each transesterification reaction is preferably (1.5-5): 1, more preferably (2.5-4): 1, and still more preferably 3.5: 1.
In the present invention, the catalyst is preferably sodium methoxide or lipase. In the present invention, the mass of the catalyst is preferably 0.3 to 8%, more preferably 0.5 to 5% of the mass of the single-component fatty acid monoester in the corresponding transesterification reaction. In the invention, the catalyst can induce the transesterification reaction to proceed towards the generation of the single-component triglyceride, thereby improving the yield of the single-component triglyceride.
In the invention, the temperature of the ester exchange reaction is preferably 200-300 ℃, and more preferably 230-280 ℃. In the present invention, the time for the transesterification is preferably 30 to 90min, and more preferably 40 to 60 min. The present invention controls the temperature and time of the transesterification reaction within the above-mentioned ranges to facilitate the conversion of as much of the mono-component fatty acid monoester as possible into the mono-component triglyceride.
After the transesterification reaction is completed, the present invention preferably performs adsorption, filtration, alkali refining, water washing and drying on the products of the respective transesterification reactions in sequence to obtain the single-component triglyceride.
In the present invention, the adsorption is preferably performed under stirring conditions. The stirring speed is not specially limited, and the components are uniformly mixed. In the invention, the adsorption temperature is preferably 70-80 ℃, and more preferably 75-85 ℃. In the present invention, the adsorbent used for the adsorption is preferably a mixture of activated carbon and clay. In the present invention, the mass of the activated carbon is preferably 1 to 4%, more preferably 1.5 to 3% of the mass of the product of the transesterification reaction. In the present invention, the clay is preferably 1 to 4% by mass, more preferably 1.5 to 3% by mass, of the product of the transesterification reaction. In the present invention, the adsorption enables decolorization of the product of the transesterification reaction and removal of impurities.
The filtration method is not particularly limited in the present invention, and a method well known in the art may be used. In the present invention, the filter screen used for the filtration is preferably a filter screen with a pore size of 0.1 μm.
In the invention, the alkali refining mode is preferably to heat the filtered products of each transesterification reaction in a water bath at 50 ℃, then to control the speed of 5 mL/min to add alkali liquor, to continue stirring for 2 hours after the alkali liquor is added, then to raise the temperature to 80 ℃, to stand for 2 hours, and to take out the upper layer of each single component triglyceride after the standing is completed. In the present invention, the alkali used for alkali refining is preferably sodium hydroxide or potassium hydroxide. In the present invention, the base is preferably added in the form of an aqueous solution; the mass concentration of the aqueous solution is preferably 1 g/L. In the present invention, the acid value of the alkali-refined product is preferably 0.08KOHmg/g or less, and more preferably 0.06KOHmg/g or less. In the present invention, the alkali refining can reduce the acid value of each product of the transesterification reaction after filtration to remove water-soluble impurities.
In the present invention, the number of washing with water is preferably 2 to 4. In the invention, the temperature of the water washing is preferably 70-80 ℃, and more preferably 75-85 ℃. The invention controls the temperature and the times of water washing within the range, and is beneficial to removing water-soluble impurities produced in the alkali refining process as much as possible.
The drying method is not particularly limited in the present invention, and the moisture removal can be achieved by a technical scheme well known in the art.
After obtaining various single-component triglycerides, the invention mixes the single-component triglycerides to obtain the natural ester insulating oil.
In the present invention, the manner of mixing the individual mono-component triglycerides is preferably selected to be different depending on the suitable region. In the embodiment of the present invention, the mixing method particularly suitable for the general area is preferably glycerol trioleate, or the mixing method suitable for the low-temperature area is preferably a mixing method in which the mass ratio of 1: 1 with glycerol trioleate.
In the present invention, the mixing preferably further comprises adding one or more of an antioxidant, a pour point depressant and a passivating agent.
In the present invention, the antioxidant is preferably one or more of tert-butylhydroquinone (TBHQ), Butylhydroxyanisole (BHA) and 2, 6-di-tert-butyl-p-cresol (BHT). In the present invention, the antioxidant is preferably 0.15 to 0.5% by mass, more preferably 0.25 to 4% by mass, based on the natural ester insulating oil. In the present invention, the antioxidant can further enhance the antioxidant ability of the natural ester insulating oil.
In the present invention, the pour point depressant is preferably one or more of polymethyl methacrylate (PMMA), ethylene-vinyl acetate copolymer, and poly-a-olefin. In the present invention, the mass of the pour point depressant is preferably 0.1 to 1.0)% of the mass of the natural ester insulating oil, and more preferably 0.3 to 0.8%. In the invention, the pour point depressant can reduce the pour point of the natural ester insulating oil and improve the application range of the natural ester insulating oil in low-temperature regions.
In the invention, the passivating agent is preferably one or more of N, N' -disalicylidene propylene diamine, dibenzyl disulfide, tolyltriazole TTA and Irgamet 39. In the invention, the mass of the passivating agent is preferably 0.05-0.8% of the mass of the natural ester insulating oil, and more preferably 0.1-0.3%. In the invention, the passivator can inhibit the catalytic action of active metal ions (copper, iron, nickel, manganese and the like) on the oxidation of the natural ester insulating oil and improve the stability of the natural ester insulating oil.
According to the preparation method provided by the invention, triglyceride contained in the raw oil and alcohol are subjected to ester exchange reaction to obtain the fatty acid monoester which is low in kinematic viscosity and easy to separate (the separation difficulty is far less than that of the triglyceride and the fatty acid), so that the requirement on the purity of the raw oil is greatly reduced, the source of the raw material is expanded, then the raw oil and the glycerol are subjected to ester exchange reaction to obtain the single-component triglyceride with the same high-purity three fatty acid groups, and the natural ester insulating oil prepared by combining the single-component triglyceride with the same high-purity three fatty acid groups has low pour point and condensation point, can be used in low-temperature regions and has low kinematic viscosity.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without any inventive step, are within the scope of the present invention.
Example 1
(1) Taking 1800g of recovered oil as raw oil, filtering the raw oil for two cycles at the temperature of 60 ℃ by using a filtering device with the size of a filter element of 50 mu m, obtaining pretreated oil, and then stirring the raw oil at the temperature of 45 ℃ according to the mass ratio of citric acid to the pretreated oil of 3 g: 1kg, mixing the pretreated oil material and citric acid, carrying out acid degumming to obtain acid degumming oil material, and then stirring at 45 ℃ according to the mass ratio of deionized water to the acid degumming oil material of 40 g: 1kg, mixing the oil material subjected to acid degumming with deionized water, stirring at 80 ℃ for 30 minutes, standing at 80 ℃ for 2 hours, and separating liquid to obtain dephosphorized grease; the volume of citric acid is (5)% of the volume of the pretreated oil; the volume of the deionized water is 5% of the volume of the oil material after acid degumming; the mass concentration of phospholipid in the dephosphorized fatty oil is less than 50 mg/kg;
(2) mixing the dephosphorized fatty oil obtained in the step (1) with methanol and concentrated sulfuric acid with the mass fraction of 98%, carrying out ester exchange reaction for 8 hours at 70 ℃, then washing a product of the obtained ester exchange reaction for 2 times at 80 ℃ with deionized water, drying, then adding activated carbon and argil, stirring and adsorbing for 2 hours at 60 ℃, and filtering to obtain pure mixed fatty acid monoester; the volume of the methanol is 5% of that of the dephosphorized grease, and the mass of the concentrated sulfuric acid with the mass fraction of 98% is preferably 5% of that of the dephosphorized grease; the mass of the activated carbon is preferably 2% of the mass of the product of the transesterification reaction; the mass of said clay is preferably 5% of the mass of the product of said transesterification reaction;
(3) mixing the mixed fatty acid monoester obtained in the step (2) with methanol, cooling at the speed of 2 ℃/min for solvent crystallization, cooling to 10 ℃, filtering to obtain methyl stearate and methyl palmitate, cooling to 0 ℃, filtering to obtain methyl oleate, cooling to-20 ℃, filtering to obtain methyl linoleate, and repeating the process until the purity of the methyl oleate and the methyl linoleate (the purity is detected by gas chromatography) is more than 90%; the volume of the methanol is preferably 5% of the volume of the mixed fatty acid monoester;
(4) respectively carrying out transesterification on various single-component fatty acid monoesters obtained in the step (3), namely stearic acid/methyl palmitate, methyl oleate and methyl linoleate, and glycerol under the action of a catalyst sodium methoxide, firstly carrying out transesterification for 2 hours under the conditions of 50 ℃ and 0.08MPa of vacuum degree and stirring, then carrying out transesterification for 5 hours under the conditions of 65 ℃ and 0.05MPa of vacuum degree and stirring, then adding activated carbon and argil into the obtained product of the transesterification, stirring and adsorbing for 2 hours at 60 ℃, filtering, then adding 0.32L of sodium hydroxide solution with the mass concentration of 0.9g/L for alkali refining, washing for 2 times with deionized water at 80 ℃, and drying to obtain various single-component triglycerides, namely glycerol tristearate/palmitate, glycerol trioleate and glycerol trioleate;
in each transesterification reaction: the mass of the catalyst sodium methoxide is 0.8 percent of the mass of the corresponding single-component fatty acid monoester; the volume ratio of glycerol to the corresponding mono-component fatty acid monoester was 3.5: 1; the mass of the activated carbon is preferably 2% of the mass of the product of the transesterification reaction; the mass of said clay is preferably 5% of the mass of the product of said transesterification reaction; the acid value of the alkali refining product is less than or equal to 0.02 KOHmg/g;
(5) mixing the glycerol trioleate obtained in the step (4) with an antioxidant, namely butyl hydroxy anisole and a passivating agent to obtain natural ester insulation; the mass of the antioxidant is 0.3% of that of the natural ester insulating oil; the mass of the passivating agent is 0.01% of that of the natural ester insulating oil.
Example 2
A natural ester insulating oil was prepared according to the procedure of example 1;
wherein the step (4) is carried out with glycerol for 13h under the action of catalyst lipase and the conditions of 90 ℃ and stirring, and the mass of the catalyst lipase is 4% of that of each single-component fatty acid monoester.
Example 3
A natural ester insulating oil was prepared according to the procedure of example 1;
wherein, the mass ratio of 1: 1, mixing glycerol trioleate and glycerol trioleate, and then mixing with an antioxidant butyl hydroxy anisole and a passivating agent to obtain natural ester insulation; the mass of the antioxidant is 0.3% of that of the natural ester insulating oil; the mass of the passivating agent is 0.01% of that of the natural ester insulating oil.
The parameters of the natural ester insulating oil prepared in the embodiments 1-3 and the parameters of the traditional natural ester insulating oil (FR 3 produced by Jiaji company, USA) are respectively detected by different detection methods, and the specific detection method and the detection result are shown in Table 1;
wherein, the antioxidant capacity is detected according to the IEC62770 standard.
TABLE 1 comparison of Natural ester insulating oil parameters prepared in examples 1-3 with conventional Natural ester insulating oils
As can be seen from examples 1-3 and Table 1, the kinematic viscosity of the natural ester insulating oil prepared by the method provided by the application is as low as 6mm at 100 DEG C2S, kinematic viscosity at 40 ℃ as low as 30mm2The pour point is as low as minus 28 ℃, the oxidation resistance is better, and the insulating property is better than that of a traditional cableTraditional natural esters of systems. According to the preparation method provided by the invention, the raw oil containing the recovered oil is used as the raw material to prepare the natural ester insulating oil, the requirement on the purity of the raw oil is low, the problem of grain competition with people is avoided, the prepared natural ester insulating oil has a low pour point and a low condensation point, can be used in low-temperature areas, and has low kinematic viscosity.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A preparation method of natural ester insulating oil comprises the following steps:
(1) degumming raw oil to obtain dephosphorized grease oil, wherein the raw oil comprises recovered oil;
(2) carrying out ester exchange reaction on the dephosphorized fatty oil obtained in the step (1) and alcohol, and then carrying out impurity removal treatment to obtain mixed fatty acid monoester;
(3) carrying out solvent crystallization separation on the mixed fatty acid monoester obtained in the step (2) to obtain various single-component fatty acid monoesters;
(4) performing ester exchange reaction on the single-component fatty acid monoesters obtained in the step (3) and glycerol respectively under the action of a catalyst to obtain single-component triglycerides;
(5) and (4) mixing the single-component triglycerides obtained in the step (4) to obtain the natural ester insulating oil.
2. The method according to claim 1, wherein the degumming treatment in step (1) further comprises a filtration treatment.
3. The preparation method according to claim 1, wherein the degumming treatment in the step (1) comprises acid degumming and hydration degumming performed in sequence.
4. The process according to claim 1, wherein the concentration of phospholipids in the dephosphorized fat oil obtained in step (1) is less than 60 mg/kg.
5. The method according to claim 1, wherein the alcohol in step (2) is methanol or ethanol, and the volume of the alcohol is 10 to 20% of the volume of the dephosphorized fat oil.
6. The preparation method according to claim 1, wherein the temperature of the transesterification reaction in the step (2) is 50 to 70 ℃ and the time of the transesterification reaction is 2 to 6 hours.
7. The method according to claim 1, wherein the impurity removal treatment in the step (2) comprises washing, adsorbing and filtering the product of the transesterification reaction sequentially.
8. The method according to claim 1, wherein the solvent crystallization separation in step (3) comprises mixing the mixed fatty acid monoester and alcohol, cooling at a speed of 2-5 ℃/min, and filtering to separate various single-component fatty acid monoester solids precipitated within a temperature gradient.
9. The method according to claim 1, wherein the catalyst in step (4) is sodium methoxide or lipase.
10. The method of claim 1, wherein the mixing of step (5) further comprises adding one or more of an antioxidant, a pour point depressant, and a passivating agent.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102682869A (en) * | 2012-04-11 | 2012-09-19 | 中国电力科学研究院 | Vegetable insulating oil, and preparation method of vegetable insulating oil |
| CN104711126A (en) * | 2015-02-13 | 2015-06-17 | 新疆福克油品股份有限公司 | High-quality utilization method for waste oil |
| CN106635432A (en) * | 2016-11-25 | 2017-05-10 | 四川金谷能源科技有限公司 | Method for preparing vegetable insulating oil by utilizing swill oil |
| CN112708507A (en) * | 2020-11-11 | 2021-04-27 | 广东电网有限责任公司 | Acid reduction process for preparing kitchen waste grease-based natural ester insulating oil |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102682869A (en) * | 2012-04-11 | 2012-09-19 | 中国电力科学研究院 | Vegetable insulating oil, and preparation method of vegetable insulating oil |
| CN104711126A (en) * | 2015-02-13 | 2015-06-17 | 新疆福克油品股份有限公司 | High-quality utilization method for waste oil |
| CN106635432A (en) * | 2016-11-25 | 2017-05-10 | 四川金谷能源科技有限公司 | Method for preparing vegetable insulating oil by utilizing swill oil |
| CN112708507A (en) * | 2020-11-11 | 2021-04-27 | 广东电网有限责任公司 | Acid reduction process for preparing kitchen waste grease-based natural ester insulating oil |
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Application publication date: 20211221 |