Compound additive for vegetable insulating oil and preparation method thereof

Abstract

The invention discloses a composite additive for vegetable insulating oil and a preparation method, and belongs to the technical field of insulating oil. The composite additive provided by the invention comprises insulating oil base oil and an additive, the base oil is rapeseed oil, and the additive is composed of an antioxidant, a pour point reducing agent and a metal corrosion inhibitor. The mass of the antioxidant, the mass of the pour point reducing agent and the mass of the metal corrosion inhibitor account for 6%-10%, 4%-8% and 2%-5% of the mass of the base oil respectively. The composite additive provided by the invention can significantly improve the oxidation resistance and low temperature performance of the vegetable insulating oil, and has good compatibility with the vegetable insulating oil. According to the preparation method of the composite additive provided by the invention, the insulating oil and the additive are prevented from being subjected to oxidation reaction under the conditions of high temperature and oxygen contact to a certain extent, and a quality guarantee is provided for subsequent use of the vegetable insulating oil.

Description

Technical Field

[0001] The invention belongs to the technical field of insulating oils and relates to a composite additive for vegetable insulating oil and a preparation method thereof. Background Art

[0002] At present, oil-immersed transformers mainly use mineral insulating oil, but mineral insulating oil has the disadvantages of being non-renewable, having low biodegradability, and being flammable and explosive. Vegetable insulating oil is a highly environmentally friendly and safe liquid insulating material with a high ignition point, good safety, high biodegradability, non-toxicity, and the ability to reduce carbon emissions and be environmentally friendly. Vegetable insulating oil is an ideal successor to mineral insulating oil. With energy and environmental issues receiving increasing attention and under the strong promotion of national policies, the application of vegetable insulating oil has been growing year by year.

[0003] The main component of vegetable insulating oil is triglyceride, which contains a large number of carbon-carbon unsaturated bonds and ester bonds, making it less resistant to oxidation than mineral insulating oil. In addition, its molecular weight is larger than that of mineral insulating oil, and its low-temperature performance is far inferior to that of mineral insulating oil. In the preparation process of vegetable insulating oil, various additives need to be added, including solids and liquids. In the process of adding, there are problems such as uneven dispersion or complicated adding process. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems of low oxidation resistance and low temperature performance of existing vegetable insulating oil, uneven dispersion of various additives in the preparation process of vegetable insulating oil and complex process. In order to solve the above technical problems, the present invention provides a composite additive for vegetable insulating oil and a preparation method thereof.

[0005] In one aspect, the present invention provides a composite additive for vegetable insulating oil, comprising the following components: base oil, antioxidant, pour point depressant, metal corrosion inhibitor;

[0006] The antioxidant is added in an amount of 6% to 10% of the base oil mass;

[0007] The pour point depressant is added in an amount of 4% to 8% of the base oil mass;

[0008] The added amount of the metal corrosion inhibitor is 2% to 5% of the base oil mass.

[0009] Preferably, in the composite additive for vegetable insulating oil of the present invention, the base oil is rapeseed oil;

[0010] The antioxidants are butylated hydroxyanisole and propyl gallate;

[0011] The pour point depressant is a styrene-maleate copolymer;

[0012] The metal corrosion inhibitor is IRGAMET 39.

[0013] Preferably, in the composite additive for vegetable insulating oil of the present invention, the mass ratio of butylated hydroxyanisole to propyl gallate in the antioxidant is 3:1.

[0014] On the other hand, the present invention provides a method for preparing a composite additive for vegetable insulating oil, comprising the following steps:

[0015] (1) Under vacuum conditions, the base oil was heated, an antioxidant was added, and the mixture was stirred for 1.5 hours to obtain oil sample 1;

[0016] (2) maintaining vacuum conditions, cooling oil sample 1, adding a pour point depressant, and stirring for 0.5 h to obtain oil sample 2;

[0017] (3) Maintaining vacuum conditions, adding a metal corrosion inhibitor to oil sample 3, stirring for 1.5 hours, and then cooling to room temperature to obtain a composite additive for vegetable insulating oil.

[0018] Preferably, in the method for preparing the composite additive for vegetable insulating oil of the present invention, the vacuum degree of the vacuum conditions in step (1), step (2) and step (3) is 20 to 50 mmHg.

[0019] Preferably, in the method for preparing the composite additive for vegetable insulating oil of the present invention, the base oil in step (1) is heated to 75±5°C.

[0020] Preferably, in the method for preparing the composite additive for vegetable insulating oil of the present invention, the base oil in step (1) is rapeseed oil;

[0021] The antioxidant is added in an amount of 6% to 10% of the base oil mass;

[0022] The antioxidants are butylated hydroxyanisole and propyl gallate;

[0023] The mass ratio of butylated hydroxyanisole to propyl gallate is 3:1.

[0024] Preferably, in the method for preparing the composite additive for vegetable insulating oil of the present invention, in the step (2), the oil sample 1 is cooled to 55±5°C.

[0025] Preferably, in the method for preparing the composite additive for vegetable insulating oil of the present invention, the amount of the pour point depressant added in step (2) is 4% to 8% of the mass of the base oil;

[0026] The pour point depressant is a styrene-maleate copolymer.

[0027] Preferably, in the method for preparing the composite additive for vegetable insulating oil of the present invention, the amount of the metal corrosion inhibitor added in step (3) is 2% to 5% of the mass of the base oil;

[0028] The metal corrosion inhibitor is IRGAMET 39.

[0029] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages:

[0030] The composite additive provided by the present invention comprises an insulating oil base oil and an additive, wherein the base oil is rapeseed oil, and the additive consists of an antioxidant, a pour point depressant and a metal corrosion inhibitor. The masses of the antioxidant, the pour point depressant and the metal corrosion inhibitor account for 6% to 10%, 4% to 8% and 2% to 5% of the mass of the base oil, respectively. The composite additive of the present invention can significantly improve the antioxidant performance and low temperature performance of the vegetable insulating oil, and has good compatibility with the vegetable insulating oil. The preparation method of the composite additive provided by the present invention avoids the oxidation reaction of the insulating oil and the additive under the conditions of high temperature and contact with oxygen to a certain extent, and provides quality assurance for the subsequent use of the vegetable insulating oil. DETAILED DESCRIPTION

[0031] The technical scheme of the present invention is described below in conjunction with the embodiments, but the present invention is not limited to the following embodiments. The experimental methods and detection methods described in each embodiment are conventional methods unless otherwise specified; the reagents and materials described are all commercially available unless otherwise specified.

[0032] Example 1

[0033] This embodiment provides a formula composition of a composite additive for vegetable insulating oil.

[0034] The formula of the composite additive for vegetable insulating oil in this embodiment is rapeseed oil (base oil), 10% by mass of rapeseed oil of antioxidant (butylated hydroxyanisole: propyl gallate = 1:3), 8% by mass of rapeseed oil of pour point depressant (styrene-maleate copolymer) and 5% by mass of rapeseed oil of metal corrosion inhibitor (IRGAMET 39).

[0035] Example 2

[0036] This embodiment provides a formula composition of a composite additive for vegetable insulating oil.

[0037] The formula of the composite additive for vegetable insulating oil in this embodiment is rapeseed oil (base oil), 6% by mass of rapeseed oil of antioxidant (butylated hydroxyanisole: propyl gallate = 1:3), 4% by mass of rapeseed oil of pour point depressant (styrene-maleate copolymer) and 2% by mass of rapeseed oil of metal corrosion inhibitor (IRGAMET 39).

[0038] Example 3

[0039] This embodiment provides a formula composition of a composite additive for vegetable insulating oil.

[0040] The formula of the composite additive for vegetable insulating oil in this embodiment is rapeseed oil (base oil), 8% by mass of rapeseed oil of antioxidant (butylated hydroxyanisole: propyl gallate = 1:3), 6% by mass of rapeseed oil of pour point depressant (styrene-maleate copolymer) and 3% by mass of rapeseed oil of metal corrosion inhibitor (IRGAMET 39).

[0041] Example 4

[0042] The invention provides a method for preparing a composite additive for vegetable insulating oil.

[0043] The specific preparation method of the composite additive for vegetable insulating oil described in Examples 1 to 3 is as follows:

[0044] (1) Rapeseed oil was injected into a reactor, and the temperature was raised to 75±5°C under a vacuum degree of 20 to 50 mmHg, and an antioxidant was added, wherein the antioxidant was butylated hydroxyanisole and propyl gallate (butylated hydroxyanisole: propyl gallate = 3:1), and the vacuum degree was maintained at 20 to 50 mmHg and stirred for 1.5 hours to obtain oil sample 1;

[0045] (2) The temperature of oil sample 1 is lowered to 55±5°C while maintaining a vacuum degree of 20 to 50 mmHg, and then a pour point depressant is added to the reaction vessel. The pour point depressant is a styrene-maleate copolymer, and the mixture is stirred for 0.5 h under a vacuum degree of 20 to 50 mmHg to obtain oil sample 2;

[0046] (3) Adding a metal corrosion inhibitor, IRGAMET 39, to oil sample 2, stirring for 1.5 h under a vacuum degree of 20 to 50 mmHg, and cooling to room temperature to obtain a composite additive for vegetable insulating oil.

[0047] Comparative Example 1

[0048] This comparative example provides the performance of the vegetable insulating oil after adding the composite additive for vegetable insulating oil.

[0049] Sample 1: 100% rapeseed oil (base oil);

[0050] Sample 2: 99% rapeseed oil (base oil) + 1% composite additive for plant insulation (same as Example 1);

[0051] Sample 3: 99% rapeseed oil (base oil) + 1% composite additive for plant insulation (same as Example 2);

[0052] Sample 4: 99% rapeseed oil (base oil) + 1% composite additive for plant insulation (same as Example 3);

[0053] Sample 5: 99% rapeseed oil (base oil) + 1% composite additive for plant insulation (no pour point depressant styrene-maleate copolymer is added, and the rest is the same as Example 1);

[0054] Sample 6: 99% rapeseed oil (base oil) + 1% composite additive for plant insulation (without adding antioxidant butyl hydroxyanisole and propyl gallate, and the rest is the same as Example 1);

[0055] Sample 7: 99% rapeseed oil (base oil) + 1% composite additive for plant insulation (without adding metal corrosion inhibitor IRGAMET 39, and the rest is the same as Example 1).

[0056] Table 1 Main performance parameters of vegetable insulating oil prepared in comparative example

[0057]

[0058]

[0059] Since the preparation process of the composite additive for plant insulation provided in Example 1 is carried out under vacuum throughout the process, the natural ester (rapeseed oil) and the composite additive for plant insulation are prevented from undergoing oxidation reaction under high temperature and oxygen contact conditions, providing quality assurance for the subsequent use of plant insulating oil. The base oil in the formula of the composite additive for plant insulation provided by the present invention is rapeseed oil, so the composite additive for plant insulation of the present invention has good compatibility with plant insulating oil, and there is no uneven dispersion of the additive. As can be seen from Table 1, after the composite additive for plant insulating oil is added with natural ester, the antioxidant and low temperature properties of the plant insulating oil can be significantly improved without affecting the various properties of the plant insulating oil. Specifically, compared with sample 1 without adding the composite additive, the performance of sample 2 with the composite additive added is more superior. In terms of dielectric loss factor, the value of sample 2 is lower, which means that it has less energy loss in the electric field and higher insulation efficiency. At the same time, the flash point and ignition point of sample 2 are both higher than those of sample 1, which shows its better thermal stability and safety. The pour point of sample 2 is lower than that of sample 1, and the reduction in the pour point means that the insulating oil can still maintain good fluidity at a lower temperature. In addition, in the oxidation stability test, the increase in total acid value and kinematic viscosity of Sample 2 were much lower than those of Sample 1, and the increase in dielectric loss factor was also smaller, which fully demonstrated the excellent effect of the composite additive in improving the antioxidant properties of vegetable insulating oil.

[0060] In addition, samples 5 to 7 omitted the addition of pour point depressants, antioxidants and metal corrosion inhibitors during the preparation process. This change resulted in a significant increase in the key performance indicators of the prepared vegetable insulating oil. First, the total acid value of the vegetable insulating oil obtained from these samples (samples 5 to 7) without the addition of specific additives increased, indicating that the aging degree of the vegetable insulating oil increased and the stability decreased. Secondly, the kinematic viscosity also showed an increasing trend, resulting in a decrease in the circulation efficiency of the insulating oil in the equipment, thereby affecting the overall performance and life of the equipment. Furthermore, the dielectric loss factor also increased, which means that the insulating performance of the insulating oil decreased. The above results further show that the composite additive for vegetable insulating oil provided by the present invention significantly improves the antioxidant and low-temperature properties of the vegetable insulating oil, and the absence of any component may lead to a decrease in the overall performance.

[0061] The embodiments described above are part of the embodiments of the present invention, but not all of them. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but only represents selected embodiments of the present invention. All other embodiments obtained without creative work and related deductions and substitutions made by ordinary technicians in the field under the conditions of the concept of the present invention belong to the scope of protection of the present invention.

Claims

1. A composite additive for vegetable insulating oil, characterized in that: The composite additive for vegetable insulating oil comprises: base oil, antioxidant, pour point depressant, and metal corrosion inhibitor; The antioxidant is added in an amount of 6% to 10% of the base oil mass; The pour point depressant is added in an amount of 4% to 8% of the base oil mass; The added amount of the metal corrosion inhibitor is 2% to 5% of the base oil mass.

2. The composite additive for vegetable insulating oil according to claim 1, characterized in that: The base oil is rapeseed oil; The antioxidants are butylated hydroxyanisole and propyl gallate; The pour point depressant is a styrene-maleate copolymer; The metal corrosion inhibitor is IRGAMET 39.

3. The composite additive for vegetable insulating oil according to claim 2, characterized in that: The mass ratio of butylated hydroxyanisole to propyl gallate in the antioxidant is 3:

1.

4. A method for preparing a composite additive for vegetable insulating oil, characterized in that: The following steps are involved: (1) Under vacuum conditions, the base oil was heated, an antioxidant was added, and the mixture was stirred for 1.5 hours to obtain oil sample 1; (2) maintaining vacuum conditions, cooling oil sample 1, adding a pour point depressant, and stirring for 0.5 h to obtain oil sample 2; (3) Maintaining vacuum conditions, adding a metal corrosion inhibitor to oil sample 3, stirring for 1.5 hours, and then cooling to room temperature to obtain a composite additive for vegetable insulating oil.

5. The preparation method according to claim 4, characterized in that: The vacuum degree of the vacuum conditions in step (1), step (2) and step (3) is 20 to 50 mmHg.

6. The preparation method according to claim 4, characterized in that: The base oil in step (1) is heated to 75±5°C.

7. The preparation method according to claim 4, characterized in that: The base oil in step (1) is rapeseed oil; The antioxidant is added in an amount of 6% to 10% of the base oil mass; The antioxidants are butylated hydroxyanisole and propyl gallate; The mass ratio of butylated hydroxyanisole to propyl gallate is 3:

1.

8. The preparation method according to claim 4, characterized in that: In the step (2), the oil sample 1 is cooled to 55±5°C.

9. The preparation method according to claim 4, characterized in that: The amount of the pour point depressant added in step (2) is 4% to 8% of the mass of the base oil; The pour point depressant is a styrene-maleate copolymer.

10. The preparation method according to claim 4, characterized in that: The amount of the metal corrosion inhibitor added in step (3) is 2% to 5% of the mass of the base oil; The metal corrosion inhibitor is IRGAMET 39.

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