Screening method of composite anti-degradation agent for insulating oil and insulating oil

Abstract

The invention relates to the technical field of alkylbenzene insulating oil, in particular to a screening method of a composite anti-degradation agent for insulating oil and the insulating oil. The screening method comprises the following steps: preparing a series of solutions for test products according to a preset type of phenolic antioxidant, a preset type of amine antioxidant and a preset type of metal deactivator; the test sample series solution comprises different composite anti-degradation agents; storing the test sample series solution in a preset degradation environment to obtain a detection result; wherein the factor of the detection result comprises an acid value; carrying out range analysis of stability multiples on the acid value by adopting a chemometrics method, and screening out a preset type of a phenolic antioxidant, a preset type of an amine antioxidant and a preset type of a metal deactivator which have the highest influence degree on the acid value; and screening the type of the composite anti-degradation agent according to the analysis result. The method provided by the invention has the advantages of small sample size, high efficiency and reliable and accurate screening result.

Description

Technical Field

[0001] The present application relates to the technical field of alkylbenzene insulating oil, and in particular to a method for screening a composite anti-deterioration agent for insulating oil and insulating oil. Background Art

[0002] Alkylbenzene insulating oil has become the main insulating medium for submarine oil-filled cables and 500kV ultra-high voltage cables due to its good gas evolution, low viscosity and good biodegradability. However, actual operating experience has found that aging and decomposition will occur during the long-term operation of cables and long-term storage of alkylbenzene insulating oil. This process will cause its physical, chemical and electrical properties to deteriorate, which will have an adverse effect on the safe and stable operation of oil-filled cables.

[0003] The addition of antioxidants will reduce the aging degree of alkylbenzene insulating oil. At present, the composite antioxidants for insulating oil mainly include phenolic antioxidants, amine antioxidants and metal passivators; however, there are many types of phenolic antioxidants, amine antioxidants and metal passivators, and there are many combinations when they are used in combination. Therefore, a method is needed to screen composite antioxidants to obtain composite antioxidants with excellent anti-degradation properties. Summary of the invention

[0004] Based on this, the present application provides a screening method for a composite anti-degradation agent for insulating oil and insulating oil. The method provided in the present application can screen out the types of composite anti-degradation agents based on the range analysis of stability multiples, and the method has the advantages of small sample size, high efficiency, and reliable and accurate screening results.

[0005] In a first aspect of the present application, a method for screening a composite anti-degradation agent for insulating oil is provided, wherein the composite anti-degradation agent comprises a phenolic antioxidant, an amine antioxidant and a metal passivator; the screening method comprises the following steps:

[0006] According to preset types of phenolic antioxidants, preset types of amine antioxidants, and preset types of metal passivators, a series of test sample solutions are prepared; the series of test sample solutions include composite anti-degradation agents obtained by combining preset types of phenolic antioxidants, preset types of amine antioxidants, and preset types of metal passivators in different types;

[0007] The test sample series solutions are stored in a preset deterioration environment to obtain test results; wherein the test results include acid value;

[0008] Performing a range analysis of the stability multiples on the acid value using a chemometric method, and respectively screening out the preset types of the phenolic antioxidant, the preset types of the amine antioxidant, or the preset types of the metal passivator that have the greatest impact on the acid value;

[0009] The type of the composite anti-degradation agent is determined according to the results of the analysis.

[0010] In one embodiment, the step of performing a range analysis of stability multiples on the acid value using a chemometric method comprises:

[0011] The acid value stability multiples of phenolic antioxidants under different preset types, the acid value stability multiples of amine antioxidants under different preset types, and the acid value stability multiples of metal passivators under different preset types are calculated respectively; wherein the value of the acid value stability multiple is positively correlated with the degree of acid value influence;

[0012] Determine the acid value extreme difference of the phenolic antioxidant, the acid value extreme difference of the amine antioxidant, and the acid value extreme difference of the metal passivator according to the acid value stability multiple;

[0013] The acid value extreme difference of the phenolic antioxidant = the difference between the highest value and the lowest value of the acid value stability multiples of the phenolic antioxidant under different preset types;

[0014] The acid value extreme difference of the amine antioxidant = the difference between the highest value and the lowest value of the acid value stability multiple of the amine antioxidant under different preset types;

[0015] The acid value extreme difference of the metal passivator=the difference between the highest value and the lowest value of the acid value stability multiples of the metal passivator under different preset types.

[0016] In one embodiment, the acid value stability multiple = (acid value of a blank sample without adding the composite anti-degradation agent after being stored under a preset degradation environment) / (acid value of a series of test sample solutions after being stored under a preset degradation environment).

[0017] In one embodiment, the steps of preparing a series of test sample solutions according to a preset type of phenolic antioxidant, a preset type of amine antioxidant, and a preset type of metal passivator include:

[0018] The phenolic antioxidant, the amine antioxidant and the metal passivator are used as preset factors, wherein the number of preset factors is 3;

[0019] The preset number of types of the phenolic antioxidant, the amine antioxidant and the metal passivator is the same;

[0020] An orthogonal experiment is performed according to the preset number of factors and the preset number of species to obtain the series of test sample solutions; wherein the number of the series of test sample solutions = the preset number of factors × the preset number of species.

[0021] In one embodiment, the preset type of phenolic antioxidant includes one or more of 2,6-di-tert-butyl-p-methylphenol, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 4,4'-methylenebis(2,6-di-tert-butylphenol).

[0022] In one embodiment, the preset type of amine antioxidant includes one or more of N-phenyl-α-naphthylamine, amine antioxidant L57 and amine antioxidant L06.

[0023] In one embodiment, the predetermined type of metal passivator includes one or more of the benzotriazole derivative Irgamet39, the benzotriazole derivative T551 and the thiadiazole derivative T571.

[0024] In one embodiment, the mass concentration of the phenolic antioxidant included in the test sample series solutions is the same; in the test sample series solutions, the mass concentration of the phenolic antioxidant is 0.005%~0.25%.

[0025] In one embodiment, the mass concentration of the amine antioxidant included in the test sample series solutions is the same; in the test sample series solutions, the mass concentration of the amine antioxidant is 0.0025%~0.25%.

[0026] In one embodiment, the mass concentration of the metal passivator included in the test sample series solution is the same; in the test sample series solution, the mass concentration of the metal passivator is 0.005%~0.015%.

[0027] In one embodiment, the screening method further comprises: performing quantitative analysis on the types of the screened composite anti-degradation agents.

[0028] In one embodiment, the step of quantitative analysis comprises:

[0029] The mass concentration of the metal passivator is fixed, and the phenolic antioxidant and the amine antioxidant are prepared into a first test product series solution according to different concentrations; the first test product series solution is stored under the preset degradation environment, and the mass concentration of the phenolic antioxidant is determined;

[0030] The mass concentration of the metal passivator and the mass concentration of the phenolic antioxidant are fixed, and the amine antioxidant is prepared into a second test product series solution according to different concentrations; the second test product series solution is stored under the preset degradation environment to determine the mass concentration of the amine antioxidant.

[0031] In a second aspect of the present application, an insulating oil is provided, comprising an insulating oil base oil and a composite anti-degradation agent, wherein the composite anti-degradation agent is obtained by screening by the screening method described in any embodiment of the first aspect of the present application,

[0032] The insulating oil base oil comprises alkylbenzene insulating oil;

[0033] The composite anti-degradation agent includes 2,6-di-tert-butyl-p-methylphenol, an amine antioxidant L06 and a benzotriazole derivative Irgamet39;

[0034] Optionally, in the insulating oil, the mass concentration of 2,6-di-tert-butyl-p-methylphenol is 0.1%;

[0035] Optionally, in the insulating oil, the mass concentration of the amine antioxidant L06 is 0.2%;

[0036] Optionally, in the insulating oil, the mass concentration of the benzotriazole derivative Irgamet39 is 0.01%.

[0037] In one embodiment, after the insulating oil is degraded at 120° C. for 32 days, the insulating oil has one or more of the following characteristics:

[0038] (1) The acid value of the insulating oil is 0.02 mg KOH / g to 0.35 mg KOH / g;

[0039] (2) The dielectric loss factor of the insulating oil is 0.3%~0.5%;

[0040] (3) The surface tension of the insulating oil is 35 mN / m~50 mN / m.

[0041] The screening method of the composite anti-deterioration agent for insulating oil provided in the present application has at least the following beneficial effects:

[0042] The screening method provided in the present application first prepares a series of test sample solutions, wherein the number of the test sample series solutions is lower than the number of combinations of compound anti-deterioration agents, and therefore has the advantage of a low sample size. In addition, by using a chemometric method to perform a range analysis of the stability multiples of the acid value, the types of phenolic antioxidants, amine antioxidants, and metal passivators that have the greatest impact on the acid value can be screened out, and the above-screened phenolic antioxidants, amine antioxidants, and metal passivators are compounded to obtain the optimal combination of composite anti-deterioration agents. In summary, the screening method of the present application has the advantages of low sample size, high efficiency, and reliable and accurate screening results. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is the principle diagram of the synergistic effect of phenolic antioxidant T501 and amine antioxidant L06 in insulating oil;

[0044] Figure 2 This is the action mechanism diagram of metal passivator Irgamet39 in insulating oil;

[0045] Figure 3 A bar graph showing the analysis of the stability factor of the acid value using the chemometric method;

[0046] Figure 4 A bar chart for analyzing the stability factor of dielectric loss factor using the chemometric method;

[0047] Figure 5 A bar chart for analyzing the stability factor of water using the chemometric method;

[0048] Figure 6 A bar graph showing the analysis of stability multiples using the chemometric method for interfacial tension;

[0049] Figure 7 These are the experimental results of the acid value and dielectric loss factor of the oils after aging for 50 days at 120°C with T501 and L06 in the ratio of 1:1, 1:2, 2:1, 1:3, and 3:1. DETAILED DESCRIPTION

[0050] The following is a further complete and clear description of the screening method of the composite anti-deterioration agent for insulating oil and the insulating oil of the present application in combination with specific examples. The present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0052] As used herein, "one or more" refers to any one, any two, or any two or more of the listed items.

[0053] In this application, "first aspect", "second aspect", "third aspect", "fourth aspect", "fifth aspect", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", "fifth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0054] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0055] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0056] The percentage contents involved in this application, unless otherwise specified, refer to mass percentage for solid-liquid mixing and solid-solid mixing, and refer to volume percentage for liquid-liquid mixing.

[0057] The percentage concentrations mentioned in this application, unless otherwise specified, refer to the final concentration, which refers to the percentage of the added component in the system after the addition of the component.

[0058] The temperature parameters in this application, unless otherwise specified, allow for both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows the temperature to fluctuate within the accuracy range of instrument control.

[0059] The acid value test of this application is carried out in accordance with GB / T 28552-2012 "Determination of acid value of transformer oil and turbine oil (BTB)". The dielectric loss factor test is carried out in accordance with GB / T 5654-2007 "Measurement of relative permittivity, dielectric loss factor and DC resistivity of liquid insulating materials". The moisture content test in oil is carried out in accordance with AL / T 449-2015 "Determination of moisture content of oil-immersed fibrous insulating materials". The interfacial tension test is carried out in accordance with GB / T 6541 "Determination of interfacial tension of petroleum products oil to water (ring method)".

[0060] In a first aspect of the present application, a method for screening a composite anti-degradation agent for insulating oil is provided, wherein the composite anti-degradation agent comprises a phenolic antioxidant, an amine antioxidant and a metal passivator.

[0061] The screening method comprises the following steps:

[0062] S10: preparing a series of test solutions according to preset types of phenolic antioxidants, preset types of amine antioxidants, and preset types of metal passivators; the series of test solutions include composite anti-degradation agents obtained by combining preset types of phenolic antioxidants, preset types of amine antioxidants, and preset types of metal passivators in different types.

[0063] S20: Storing the test sample series solutions under a preset degradation environment to obtain test results; wherein the test results include acid value.

[0064] S30: performing a range analysis of the stability multiples on the acid value using a chemometric method, and selecting the preset types of the phenolic antioxidant, the preset types of the amine antioxidant, or the preset types of the metal passivator that have the greatest impact on the acid value.

[0065] S40: Determine the type of the composite anti-degradation agent according to the analysis result.

[0066] In one example, step S10: the step of preparing a series of test sample solutions according to a preset type of phenolic antioxidant, a preset type of amine antioxidant, and a preset type of metal passivator includes:

[0067] S101: using the phenolic antioxidant, the amine antioxidant and the metal passivator as preset factors, wherein the number of preset factors is 3.

[0068] S102: The preset number of types of the phenolic antioxidant, the amine antioxidant, and the metal passivator is used as the preset level number.

[0069] S103: performing an orthogonal experiment according to the preset number of factors and the preset number of species to obtain the series of test sample solutions; wherein the number of the series of test sample solutions = the preset number of factors × the preset number of species.

[0070] For example, the preset number of types of the phenolic antioxidant, the amine antioxidant and the metal passivator are all the same. For example, when the preset number of types of the phenolic antioxidant, the amine antioxidant and the metal passivator are all 3, the number of combinations of the compound anti-deterioration agent is 3×3×3, which is 27. However, in the screening method of the present application, when the preset number of types of the phenolic antioxidant, the amine antioxidant and the metal passivator are all 3, the number of the test series solutions = 3×3, which is 9. Therefore, the screening method of the present application has the advantage of low sample size.

[0071] In one example, the preset type of phenolic antioxidant includes one or more of 2,6-di-tert-butyl-p-methylphenol, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 4,4'-methylenebis(2,6-di-tert-butylphenol). For example, the model of 2,6-di-tert-butyl-p-methylphenol includes but is not limited to T501. β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate includes but is not limited to L135. The model of 4,4'-methylenebis(2,6-di-tert-butylphenol) includes but is not limited to T511.

[0072] In one example, the preset type of amine antioxidant includes one or more of N-phenyl-α-naphthylamine, amine antioxidant L57 and amine antioxidant L06.

[0073] In one example, the preset type of metal passivator includes one or more of the benzotriazole derivative Irgamet39, the benzotriazole derivative T551 and the thiadiazole derivative T571.

[0074] According to the above-mentioned preset types of phenolic antioxidants, amine antioxidants and metal passivators, an orthogonal experiment was carried out, and the obtained 9 test sample series solutions are shown in Table 1.

[0075] Table 1 Types of composite anti-degradation agents in 9 test sample series solutions

[0076]

[0077] In one example, the mass concentration of the phenolic antioxidant included in the test sample series solution is the same. In the test sample series solution, the mass concentration of the phenolic antioxidant is 0.005% to 0.25%. It is understandable that the mass concentration of the phenolic antioxidant includes but is not limited to 0.005%, 0.008%, 0.01%, 0.012%, 0.015%, 0.018%, 0.05%, 0.08%, 0.1%, 0.13%, 0.15%, 0.18%, 0.2%, 0.22% or 0.25%, or any two of the above point values ​​as the range of endpoint values.

[0078] In one example, the mass concentration of the amine antioxidant included in the test solution series is the same. In the test solution series, the mass concentration of the amine antioxidant is 0.0025% to 0.25%. It is understandable that the mass concentration of the amine antioxidant includes but is not limited to 0.0025%, 0.01%, 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, 0.22% or 0.25%, or any two of the above points as the range of endpoint values.

[0079] In one example, the mass concentration of the metal passivator included in the test sample series solution is the same. In the test sample series solution, the mass concentration of the metal passivator is 0.005% to 0.015%. It is understandable that the mass concentration of the metal passivator includes but is not limited to 0.005%, 0.008%, 0.01%, 0.012% or 0.015%, or any two of the above point values ​​as the range of endpoint values.

[0080] In one specific example, in Table 1, the mass concentration of phenolic antioxidants is 0.2%, the mass concentration of amine antioxidants is 0.1%, and the mass concentration of metal passivators is 0.01%.

[0081] In one example, in step S20, the preset environment includes:

[0082] Take 200g of the test solution series and put it into a 250mL ground-mouth reagent bottle. The ground-mouth reagent bottle contains insulating paper and copper wire. The size of the insulating paper is 12.46 cm×6 cm×1mm, and the copper wire is 1mm in diameter and 4.76m long (the oil in the ground-mouth reagent bottle: the added material is 5mL:3.2cm 2 The ground-mouth reagent bottle was placed in a vacuum oven at 60°C and -0.1MPa for 24 hours to remove water, and then placed in an oven at 120°C for 32 days. It is understood that the copper wire of the above length can be coiled and added to the reagent bottle. It is understood that the area of ​​the above added material can be exemplified by the area of ​​the insulating paper.

[0083] The test results of the 9 test sample series solutions in Table 1 stored for 32 days under the above-mentioned preset degradation environment are shown in Table 2. It can be understood that the factors of the test results also include one or more of moisture, dielectric loss factor and interfacial tension. In addition, the test results of the blank samples stored for 32 days under the above-mentioned preset degradation environment are also shown in Table 2.

[0084] Table 2 Test results of the test sample series solutions stored under the preset degradation environment

[0085]

[0086] In one example, step S30: the step of performing a range analysis of the stability multiple of the acid value using a chemometric method comprises:

[0087] S301: Calculate the acid value stability multiples of phenolic antioxidants under different preset types, the acid value stability multiples of amine antioxidants under different preset types, and the acid value stability multiples of metal passivators under different preset types, wherein the value of the acid value stability multiple is positively correlated with the degree of acid value influence.

[0088] S302: Determine the acid value extremes of the phenolic antioxidant, the amine antioxidant, and the metal passivator according to the acid value stability multiple.

[0089] The acid value range of the phenolic antioxidant = the difference between the highest and lowest acid value stability multiples of the phenolic antioxidant under different preset types. The acid value range of the amine antioxidant = the difference between the highest and lowest acid value stability multiples of the amine antioxidant under different preset types;

[0090] The acid value extreme difference of the metal passivator=the difference between the highest value and the lowest value of the acid value stability multiples of the metal passivator under different preset types.

[0091] In one example, the acid value stability multiple = (acid value of a blank sample without adding a composite anti-degradation agent after being stored under a preset degradation environment) / (acid value of a series of test sample solutions after being stored under a preset degradation environment).

[0092] In step S30, the results of the range analysis of the stability multiple of the acid value using the chemometric method are shown in Table 3.

[0093] Table 3 Acid value stability multiples under different preset types

[0094]

[0095] It can be understood that the value of the acid value stability multiple of the phenolic antioxidant under different preset types is an average value. For example, the value of the acid value stability multiple of the phenolic antioxidant under the preset type T501 = [(acid value of the blank sample / acid value of the test solution series numbered 1) + (acid value of the blank sample / acid value of the test solution series numbered 2) + (acid value of the blank sample / acid value of the test solution series numbered 3)] / 3 = [2.462 / 0.044 + 2.462 / 0.061 + 2.462 / 0.055] / 3 = 47.027.

[0096] According to the test results in Table 3, among the preset types of phenolic antioxidants, the type with the highest degree of influence on acid value is T501. Among the preset types of amine antioxidants, the type with the highest degree of influence on acid value is L06. Among the preset types of metal passivators, the type with the highest degree of influence on acid value is Irgamet39. Therefore, it is determined that the types of composite anti-degradation agents include T501, L06 and Irgamet39.

[0097] In one example, the screening method further comprises:

[0098] S40: Quantitatively analyzing the types of the screened composite anti-degradation agents.

[0099] In one example, in step S40, the quantitative analysis step includes:

[0100] S401: fixing the mass concentration of the metal passivator, preparing the phenolic antioxidant and the amine antioxidant into a first test product series solution at different concentrations; storing the first test product series solution under the preset degradation environment, and determining the mass concentration of the phenolic antioxidant.

[0101] S402: fixing the mass concentration of the metal passivator and the mass concentration of the phenolic antioxidant, preparing the amine antioxidant into a second test product series solution according to different concentrations; storing the second test product series solution under the preset degradation environment, and determining the mass concentration of the amine antioxidant.

[0102] In one example, step S401 includes: fixing the mass concentration of Irgamet39 to 0.01%, adjusting the concentration ratio of T501 and L06, and preparing the first test product series solution at a ratio of 1:1, 1:2, 2:1, 1:3, and 3:1 at 120°C; storing the first test product series solution under a preset degradation environment, and detecting the changes in the acid value and dielectric loss factor of the oil product to determine the mass concentration of the phenolic antioxidant. It can be understood that the mass concentration of the phenolic antioxidant contained in the first test product series solution with the lowest acid value is the most preferred mass concentration of the phenolic antioxidant.

[0103] In one example, step S402 includes: fixing the concentration of T501 at 0.2% and the concentration of Irgamet39 at 0.01%, and changing the mass concentration of T551 to 0%, 0.025%, 0.05%, 0.075%, 0.1%, 0.125%, 0.15%, 0.2% and 0.25% to prepare a second series of test product solutions; storing the second series of test product solutions under the preset degradation environment, and determining the mass concentration of the amine antioxidant. It can be understood that the mass concentration of the amine antioxidant contained in the second series of test product solutions with the lowest acid value is the most preferred mass concentration of the amine antioxidant.

[0104] In a second aspect of the present application, an insulating oil is provided, comprising an insulating oil base oil and a composite anti-degradation agent, wherein the composite anti-degradation agent is obtained by screening by the screening method described in any example of the first aspect of the present application,

[0105] The insulating oil base oil includes alkylbenzene insulating oil.

[0106] The composite anti-degradation agent includes 2,6-di-tert-butyl-p-methylphenol, an amine antioxidant L06 and a benzotriazole derivative Irgamet39.

[0107] The synergistic effect of T501 and L06 in insulating oil is as follows Figure 1 See Figure 1T501 is a phenolic additive. It is both a free radical terminator and a peroxide decomposer. It can provide an H group to the oxidative free radical or the peroxidative free radical to generate a stable compound to prevent the chain initiation reaction. The carbon atom on the benzene ring of T501 belongs to sp 2 Hybridization has strong electron-pulling ability, so the electron cloud density of the oxygen atom on the phenolic hydroxyl group is reduced and it is not easy to leave the benzene ring, while the H on the phenolic hydroxyl group is more easily oxidized to form H·, and the phenoloxyl free radical can exist stably. The phenolic hydroxyl group reacts with the oxide to form a stable compound, thereby inhibiting the oxidation process. L06 is an amine additive that reduces the oxidation rate of oil products through the reaction of active hydrogen with free radicals. The nitrogen atom on L06 forms a conjugated system with the π electrons of the aromatic ring. The hydrogen atom connected to the nitrogen atom has a low degree of bonding and is easier to leave in the form of a proton. The proton hydrogen can combine with the free radicals in the oil to form a stable compound, thereby effectively eliminating the free radicals and increasing the initial oxidation temperature of the insulating oil.

[0108] The phenolic hydroxyl group of T501, the octyl group of L06 and the benzene ring of their own chemical structure are not in the same plane, indicating that hydrogen bonds cannot be formed between T501 and L06, and there is no chemical reaction between the two. Their synergistic effect is just a simple superposition and enhancement effect. Under the same conditions, L06 breaks the bond first to produce proton hydrogen (H·), blocking the formation of alkyl peroxyl radicals (ROO·). In addition, L06 can also react with acidic substances in oil, thereby reducing acidic products in oil and reducing the catalytic effect of acidic products.

[0109] When the L06 content gradually decreases, T501 begins to supplement proton hydrogen, maintain the proton hydrogen content, and eliminate free radicals in the oil. After that, T501 forms stable phenol oxygen free radicals. Phenolic oxygen free radicals can react with nucleophiles to form dihydroxy derivatives, which are further oxidized to form stable quinone structures. The generation of intermediates will still supply proton hydrogen to promote the regeneration of L06, and low concentrations of L06 also have a synergistic effect. When T501 is consumed, L06 continues to generate proton hydrogen to protect the insulating oil from oxidation until L06 is consumed and the antioxidant capacity fails. The mechanism of action of Irgamet39 in insulating oil is as follows Figure 2 As shown. Irgamet39 can inhibit metal activity and shield the catalytic effect of metal copper. The addition of metal passivator Irgamet39 enables it to form complexes with more metal ions and inhibit the oxidation of metal ions on alkylbenzene insulating oil.

[0110] In one example, the mass concentration of 2,6-di-tert-butyl-p-methylphenol in the insulating oil is 0.1%.

[0111] In one example, the mass concentration of the amine antioxidant L06 in the insulating oil is 0.2%.

[0112] In one example, the mass concentration of the benzotriazole derivative Irgamet39 in the insulating oil is 0.01%.

[0113] In one example, after the insulating oil is degraded at 120° C. for 32 days, the insulating oil has one or more of the following characteristics:

[0114] (1) The acid value of the insulating oil is 0.02 mg KOH / g to 0.35 mg KOH / g;

[0115] (2) The dielectric loss factor of the insulating oil is 0.3%~0.5%;

[0116] (3) The surface tension of the insulating oil is 35 mN / m~50 mN / m.

[0117] In this application, the acid value test is carried out with reference to GB / T 28552-2012 "Determination of the acid value of transformer oil and turbine oil (BTB)"; the dielectric loss factor test is carried out with reference to GB / T 5654-2007 "Measurement of relative permittivity, dielectric loss factor and DC resistivity of liquid insulating materials"; the moisture content test in oil is carried out with reference to AL / T 449-2015 "Determination of moisture content of oil-immersed fibrous insulating materials"; the interfacial tension test is carried out with reference to GB / T 6541 "Determination of interfacial tension of petroleum products oil against water (ring method)".

[0118] It has been verified that the composite anti-degradation agent obtained by the screening method provided in the present application has an excellent anti-degradation effect, so the above method has the advantage of high accuracy.

[0119] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively with reference to the relevant drawings below, and the following more specific and detailed embodiments and comparative examples which are easier to implement are also provided below as reference. Preferred embodiments of the present invention are given in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0120] Example

[0121] At present, there are literature reports that the mass concentration of the composite antioxidant is ≤0.4%; therefore, this embodiment uses the mass concentration of the phenolic antioxidant as 0.2%, the mass concentration of the amine antioxidant as 0.1%, and the mass concentration of the metal passivator as 0.01% as the preset concentrations.

[0122] (I) Prepare a series of test sample solutions according to a preset type of phenolic antioxidant, a preset type of amine antioxidant, and a preset type of metal passivator:

[0123] (I-1) Phenolic antioxidant, amine antioxidant and metal passivator are used as preset factors, wherein the number of preset factors is 3;

[0124] (I-2) The preset types of phenolic antioxidants are T501, L135 and T511; the preset types of amine antioxidants are T531, L57 and L06; the preset types of metal passivators are Irgamet39, T551 and T571; and the preset level number is 3.

[0125] (I-3) An orthogonal experiment is performed according to the preset number of factors and the preset number of species to obtain 9 test sample series solutions.

[0126] (II) Storing the test sample series solutions under a preset degradation environment and obtaining the test results:

[0127] Take 200g of the test solution series and put it into a 250mL ground-mouth reagent bottle. The ground-mouth reagent bottle contains insulating paper and copper wire. The size of the insulating paper is 12.46 cm×6 cm×1mm, and the copper wire is 1mm in diameter and 4.76m long (the oil in the ground-mouth reagent bottle: the added material is 5mL:3.2cm 2 The ground-mouth reagent bottle was placed in a vacuum drying oven at 60°C and -0.1MPa for 24 hours to remove water, and then placed in a 120°C oven for 32 days of storage. The test results of the above 9 test sample series solutions and blank samples after 32 days of storage under the above preset degradation environment are shown in Table 4.

[0128] Table 4

[0129]

[0130] (III) The acid value is subjected to a range analysis of stability multiples using a chemometric method:

[0131] (III-1) The acid value stability multiples of phenolic antioxidants under different preset types, the acid value stability multiples of amine antioxidants under different preset types, and the acid value stability multiples of metal passivators under different preset types are calculated respectively. The value of the acid value stability multiple is positively correlated with the degree of acid value influence.

[0132] (III-2) Determine the acid value extremes of the phenolic antioxidant, the amine antioxidant, and the metal passivator according to the acid value stability multiple.

[0133] The acid value, dielectric loss factor, moisture content and oxidation stability of interfacial tension of the above 9 test sample series solutions and blank samples after storage for 32 days under the above preset degradation environment are shown in Table 5 and Figure 3~Figure 6 shown. Figure 3This is a bar graph showing the analysis of the stability factor of the acid value using the chemometric method. Figure 4 A bar graph showing the analysis of the stability factor using the chemometric method for the dielectric loss factor. Figure 5 A bar graph showing the stability factor analysis of water using the chemometric method. Figure 6 The bar graph is a chemometric analysis of the stability factor of the interfacial tension.

[0134] Table 5

[0135]

[0136] From Table 5, we can conclude that: Taking acid value as the evaluation index, R 酚类添加剂 >R 金属钝化剂 >R 胺类添加剂 >R 误差列 Therefore, the influence of the anti-degradation agent on the acid value is phenolic additives > metal passivators > amine additives. Similarly, the influence of the anti-degradation agent on the dielectric loss factor is phenolic additives > amine additives > metal passivators. The influence of the anti-degradation agent on the interfacial tension is metal passivators > phenolic additives > amine additives. Taking moisture as the evaluation index, R 金属钝化剂 >R 酚类添加剂 >R 误差列 >R 胺类添加剂 The influence of additives on moisture is in the order of metal passivator > phenolic additives. The range of amine additives is smaller than the error column, so it is not a factor affecting moisture.

[0137] From Table 5 and Figure 3 It can be seen that among the phenolic additives T501, L135, and T511, the mean value K of T501 additive is the largest, which means that among the preset types of phenolic additives, T501 has the greatest impact on the acid value of oil products. Among the amine additives T531, L57, and L06, the mean value K of L06 additive is the largest; among the metal passivators Irgamet39, T551, and T571, the mean value K of Irgamet39 additive is the largest. Therefore, T501, L06, and Irgamet39 have the greatest impact on the acid value of oil products. Similarly, from Tables 4 and Figure 5 It can be concluded that T501, T531, and Irgamet39 have the greatest impact on the dielectric loss factor of oil products; Figure 5 and Figure 6 It can be concluded that T501, L57 and Irgamet39 have the greatest impact on the moisture content and interfacial tension of oil products.

[0138] (III-3) A variance analysis was performed based on the oxidation stability multiples in Table 5. The corresponding variance analysis results are shown in Table 6.

[0139] Table 6 ANOVA Results of Oxidation Stability Multiples of Phenolic Antioxidants, Amine Antioxidants, and Metal Deactivators

[0140]

[0141] In Table 6, the sum of squares between groups SSB = 3× .Y i corresponds to the oxidation stability multiples under different preset types in Table 5, which is the within-group average value.

[0142] For example, the sum of squares between groups of phenolic antioxidants SSB = 3×[(47.027 - 36.96) 2 +(27.070 - 36.96) 2 +(36.770 - 36.96) 2 =597.58.

[0143] Calculate the mean square between groups MSB = sum of squares between groups SSW / degrees of freedom = 597.58 / (3 - 1) = 298.78.

[0144] Calculate the mean square within groups MSW = 15.296 (here the mean square within groups data is the "mean square within groups" value in the corresponding "error" row in Table 6)

[0145] Calculate the F-test statistic: According to the formula F = MSB / MSW, substituting the above data gives: F = 298.779 / 15.296 ≈ 19.533.

[0146] Determine the P-value range: By referring to the F-distribution table (which can be obtained from the appendix of a statistics textbook or using statistical software), find the critical values of the F-distribution at different significance levels with degrees of freedom (2,2). Common significance levels are 0.05 and 0.01, and the corresponding critical values are assumed to be F 0.05 (2,2) and F 0.01 (2,2). Generally, F 0.05 (2,2)≈19.00, F 0.01 (2,2)≈99.00 (the actual values may vary slightly due to the precision difference of the F-distribution table).

[0147] Since the calculated F = 19.533, F 0.05 (2,2)=19.00 < 19.533 < F 0.01 (2,2)=99.00, so it can be determined that 0.01 < P < 0.05. (In professional statistical software (such as SPSS, R language), using the relevant functions of analysis of variance, inputting the original data of phenolic antioxidants under the acid value index, the software will automatically calculate the exact P-value according to the built-in algorithm).

[0148] As can be seen from Table 6, when the significance P value of a factor>0.05, it indicates that there is no significant difference in the influence of the factor on the test results, and when P<0.05, it indicates that the factor has a significant influence on the test results. It can also be concluded from Table 6 that with acid value and dielectric loss factor as evaluation indicators, only phenolic additives are significant influencing factors. Moisture, temperature, oxidation products and polar impurities all affect the dielectric loss factor, and the dielectric loss factor is greatly affected by external factors, while acid value is an acidic substance dissolved in oil produced after oil aging, and external influences have little effect on it. Phenolic additive T501, amine additive L06 and metal passivator Irgamet39 are screened out with acid value as evaluation index, so the best additive combination used in alkylbenzene insulating oil in this application is T501 + L06 + Irgamet39.

[0149] (IV) Quantitative analysis of the types of composite anti-degradation agents screened out:

[0150] (IV-1) The mass concentration of the metal passivator is fixed, and the phenolic antioxidant and the amine antioxidant are prepared into a first test product series solution at different concentrations; the first test product series solution is stored under the preset degradation environment to determine the mass concentration of the phenolic antioxidant. Specifically, the mass concentration of Irgamet39 is fixed at 0.01%, and the concentration ratio of T501 and L06 is adjusted. At 120°C, T501 and L06 are aged for 50 days in a ratio of 1:1, 1:2, 2:1, 1:3, and 3:1, and the acid value and dielectric loss factor of the oil are detected. The experimental results are shown in Figure 7 As shown. Figure 7 It can be seen that the addition ratio of 0.1% T501 and 0.2% L06 shows the lowest acid value and dielectric loss factor, indicating that the aging degree of this oil sample is the lightest under the same conditions. Therefore, the mass concentration of T501 is determined to be 0.1%.

[0151] (IV-2) The mass concentration of the metal passivator and the mass concentration of the phenolic antioxidant are fixed, and the amine antioxidant is prepared into a second series of test product solutions at different concentrations; the second series of test product solutions are stored in the preset degradation environment to determine the mass concentration of the amine antioxidant. The concentration of T501 is fixed at 0.1% and the concentration of Irgamet39 is fixed at 0.01%, and the mass concentration of T551 is changed. The changes in the acid value and dielectric loss factor of the oil at 120°C.

[0152] The above test results show that the higher the concentration of L06, the better. There is an optimal concentration point. At this concentration, L06 can effectively inhibit the generation of free radicals in oil products, and work synergistically with T501 and Irgamet 39 to improve the performance of oil products. However, once the concentration of L06 exceeds this critical value, it may disrupt the balance of chemical reactions in the oil products, destroy the synergistic effect or cause adverse interactions, and ultimately lead to reduced oil performance. When L06 has the best performance, the corresponding addition amount is 0.2%. Therefore, the mass concentration of L06 is determined to be 0.2%. The mass concentration of Irgamet39 is 0.01%.

[0153] (V) Verify the screened composite anti-degradation agent.

[0154] Under the same conditions, aging experiments were carried out on alkylbenzene insulating oil without any anti-degradation agent and with the addition of the above-mentioned 0.1% T501+0.2% L06+0.01% Irgamet39 composite anti-degradation agent. The acid value, dielectric loss factor and surface tension of the tested oil after aging are shown in Table 7.

[0155] Table 7

[0156]

[0157] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0158] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solution of the present application in detail, but it cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the content of the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A method for screening a composite anti-degradation agent for insulating oil, characterized in that: The composite anti-deterioration agent comprises a phenolic antioxidant, an amine antioxidant and a metal passivator; and the screening method comprises the following steps: According to preset types of phenolic antioxidants, preset types of amine antioxidants, and preset types of metal passivators, a series of test sample solutions are prepared; the series of test sample solutions include composite anti-degradation agents obtained by combining preset types of phenolic antioxidants, preset types of amine antioxidants, and preset types of metal passivators in different types; The test sample series solutions are stored in a preset deterioration environment to obtain test results; wherein the test results include acid value; Performing a range analysis of the stability multiples on the acid value using a chemometric method, and respectively screening out the preset types of the phenolic antioxidant, the preset types of the amine antioxidant, or the preset types of the metal passivator that have the greatest impact on the acid value; The type of the composite anti-degradation agent is determined according to the results of the analysis.

2. The method for screening a composite anti-degradation agent for insulating oil according to claim 1, characterized in that: The steps of performing a range analysis of stability multiples on the acid value using a chemometric method include: The acid value stability multiples of phenolic antioxidants under different preset types, the acid value stability multiples of amine antioxidants under different preset types, and the acid value stability multiples of metal passivators under different preset types are calculated respectively; wherein the value of the acid value stability multiple is positively correlated with the degree of acid value influence; Determine the acid value extreme difference of the phenolic antioxidant, the acid value extreme difference of the amine antioxidant, and the acid value extreme difference of the metal passivator according to the acid value stability multiple; The acid value extreme difference of the phenolic antioxidant = the difference between the highest value and the lowest value of the acid value stability multiples of the phenolic antioxidant under different preset types; The acid value extreme difference of the amine antioxidant = the difference between the highest value and the lowest value of the acid value stability multiple of the amine antioxidant under different preset types; The acid value extreme difference of the metal passivator=the difference between the highest value and the lowest value of the acid value stability multiples of the metal passivator under different preset types.

3. The method for screening a composite anti-degradation agent for insulating oil according to claim 1, characterized in that: The acid value stability multiple = (acid value of a blank sample without adding the composite anti-degradation agent after being stored under a preset degradation environment) / (acid value of a series of test sample solutions after being stored under a preset degradation environment).

4. The method for screening a composite anti-degradation agent for insulating oil according to any one of claims 1 to 3, characterized in that: The steps of preparing a series of test sample solutions according to a preset type of phenolic antioxidant, a preset type of amine antioxidant, and a preset type of metal passivator include: The phenolic antioxidant, the amine antioxidant and the metal passivator are used as preset factors, wherein the number of preset factors is 3; The preset number of types of the phenolic antioxidant, the amine antioxidant and the metal passivator is the same; An orthogonal experiment is performed according to the preset number of factors and the preset number of species to obtain the series of test sample solutions; wherein the number of the series of test sample solutions = the preset number of factors × the preset number of species.

5. The method for screening a composite anti-degradation agent for insulating oil according to any one of claims 1 to 3, characterized in that: The preset types of phenolic antioxidants include one or more of 2,6-di-tert-butyl-p-methylphenol, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 4,4'-methylenebis(2,6-di-tert-butylphenol); and / or, the preset type of amine antioxidant includes one or more of N-phenyl-α-naphthylamine, amine antioxidant L57 and amine antioxidant L06; And / or, the preset type of metal passivator includes one or more of the benzotriazole derivative Irgamet39, the benzotriazole derivative T551 and the thiadiazole derivative T571.

6. The method for screening a composite anti-degradation agent for insulating oil according to any one of claims 1 to 3, characterized in that: The test sample series solutions have one or more of the following characteristics: (1) The mass concentration of the phenolic antioxidant included in the test solution series is the same; in the test solution series, the mass concentration of the phenolic antioxidant is 0.005% to 0.25%; (2) The mass concentration of the amine antioxidant included in the test solution series is the same; in the test solution series, the mass concentration of the amine antioxidant is 0.0025% to 0.25%; (3) The mass concentration of the metal passivator included in the test sample series solutions is the same; in the test sample series solutions, the mass concentration of the metal passivator is 0.005%~0.015%.

7. The method for screening a composite anti-degradation agent for insulating oil according to claim 6, characterized in that: The screening method further comprises: performing quantitative analysis on the types of the screened composite anti-degradation agents.

8. The method for screening a composite anti-degradation agent for insulating oil according to claim 7, characterized in that: The steps of the quantitative analysis include: The mass concentration of the metal passivator is fixed, and the phenolic antioxidant and the amine antioxidant are prepared into a first test product series solution according to different concentrations; the first test product series solution is stored under the preset degradation environment, and the mass concentration of the phenolic antioxidant is determined; The mass concentration of the metal passivator and the mass concentration of the phenolic antioxidant are fixed, and the amine antioxidant is prepared into a second test product series solution according to different concentrations; the second test product series solution is stored under the preset degradation environment to determine the mass concentration of the amine antioxidant.

9. An insulating oil, characterized in that: It comprises an insulating oil base oil and a composite anti-degradation agent, wherein the composite anti-degradation agent is obtained by screening by the screening method according to any one of claims 1 to 8; The insulating oil base oil comprises alkylbenzene insulating oil; The composite anti-degradation agent includes 2,6-di-tert-butyl-p-methylphenol, an amine antioxidant L06 and a benzotriazole derivative Irgamet39; Optionally, in the insulating oil, the mass concentration of 2,6-di-tert-butyl-p-methylphenol is 0.1%; Optionally, in the insulating oil, the mass concentration of the amine antioxidant L06 is 0.2%; Optionally, in the insulating oil, the mass concentration of the benzotriazole derivative Irgamet39 is 0.01%.

10. The insulating oil according to claim 9, characterized in that After the insulating oil is degraded at 120° C. for 32 days, the insulating oil has one or more of the following characteristics: (1) The acid value of the insulating oil is 0.02 mg KOH / g to 0.35 mg KOH / g; (2) The dielectric loss factor of the insulating oil is 0.3%~0.5%; (3) The surface tension of the insulating oil is 35 mN / m~50 mN / m.

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