Low pour point high overload transformer oil, its preparation method and application

Abstract

The application provides low-tilt-point high-overload transformer oil and a preparation method and application thereof, and the preparation components include base oil and additives; the base oil includes base oil A and base oil B, and the mass ratio of the base oil A to the base oil B is (85-95):(5-15); the low-tilt-point high-overload transformer oil of the application adds 60N base oil after urea dewaxing, can effectively reduce the tilt point of the product, and improves the product performance through optimization of the base oil. The low-tilt-point high-overload transformer oil can provide insulation protection for low-temperature cold-state operation of a rural power grid; through mixing of base oils with different components, the product performance is improved and the production cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil technology, specifically relating to a low pour point, high overload transformer oil, its preparation method, and its application. Background Technology

[0002] Rural power grids have a low average annual load rate, but electricity demand is concentrated during peak periods, with a sharp increase in load during high-temperature seasons and the Spring Festival. This can easily cause short-term severe overload of conventional transformers, even leading to burnout. To address the problem of severe short-term overload operation of distribution transformers in rural areas during high-temperature seasons and the Spring Festival, and to alleviate the pressure on rural power supply during the Spring Festival, the State Grid Corporation of China has actively carried out research and development and application of high-overload capacity distribution transformers for rural power grids in recent years. This aims to improve the short-term overload capacity of distribution transformers and reduce the pressure on power supply companies to ensure power supply during peak periods.

[0003] In May 2013, research was conducted on improving the overload capacity of distribution transformers by investigating and analyzing the characteristics of rural electricity load in typical areas and the load changes during the Spring Festival. High overload distribution transformer technology is primarily developed to ensure the economic efficiency and safety of rural power grid operation. While guaranteeing basic power capacity, high overload distribution transformers can meet both the long-term power needs of small loads and the short-term power needs of overloads.

[0004] High overload distribution transformer technology places high demands on insulating fluids, stipulating that "transformer insulating fluids should comply with GB2536, and their flash point and ignition point should be higher than the transformer's insulation withstand voltage rating." Traditional mineral insulating oils have relatively low closed-cup flash points, generally around 140℃, which cannot meet the requirements of high overload distribution transformers. Therefore, new requirements have been placed on transformer oil technology, necessitating high overload transformer oils with higher closed-cup flash points to meet the needs of high overload distribution transformers.

[0005] Currently, some commercially available high overload transformer oils have flash points above 170℃, but their pour points are all above -40℃, which cannot meet the requirements for low-temperature cold-state commissioning. Therefore, a low-pour-point high overload transformer oil has been developed to meet the requirements for low-temperature cold-state commissioning. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention proposes a low pour point, high overload transformer oil, its preparation method, and its application.

[0007] In a first aspect, the present invention provides a low pour point, high overload transformer oil, the preparation components of which include base oil and additives; wherein, the base oil includes base oil A and base oil B;

[0008] Base oil A is a non-cycloalkyl base oil refined by high-pressure hydrotreating in the range of 280±10℃-425±10℃; base oil B is a base oil obtained by dewaxing a non-cycloalkyl oil fraction refined by high-pressure hydrotreating in the range of 265±10℃-425±10℃ using urea.

[0009] As a specific embodiment of the present invention, the mass ratio of base oil A to base oil B is (85-95):(5-15).

[0010] As a specific embodiment of the present invention, the additives include antioxidants, high-temperature phenolic antioxidants, and anti-gas evolution agents.

[0011] In a specific embodiment of the present invention, the antioxidant T501 is added at 0.20%-0.35 wt% of the low pour point high overload transformer oil; the high-temperature phenolic antioxidant is methyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate, which is added at 0.005%-0.01 wt% of the low pour point high overload transformer oil; and the anti-gas evolution agent is benzyltoluene, which is added at 0.01%-0.05 wt% of the low pour point high overload transformer oil.

[0012] As a specific embodiment of the present invention, the base oil A is selected from Sinopec Gaoqiao Hydrogenated HVI II2 Base Oil, Maoming Petrochemical Hydrogenated HVI II2 Base Oil and Yanshan Petrochemical Hydrogenated HVI II2 Base Oil, and its fraction is in the range of 280±10℃-425±10℃.

[0013] As a specific embodiment of the present invention, the base oil B is selected from Sinopec Gaoqiao Hydrogenated 60N base oil, Maoming Petrochemical Hydrogenated 60N base oil and Yanshan Petrochemical Hydrogenated 60N base oil after urea dewaxing treatment, and its fraction is between 265±10℃ and 425±10℃.

[0014] In a second aspect, the present invention provides a method for preparing the low pour point, high overload transformer oil described in the first aspect, comprising the following steps:

[0015] S1: Mix base oil A and base oil B evenly to obtain the first mixture;

[0016] S2: Add additives to the first mixture obtained in step S1 and mix evenly to obtain the low pour point high overload transformer oil.

[0017] As a specific embodiment of the present invention, in step S1, the mixing conditions include: a temperature of 25℃-50℃; mixing includes stirring, with a stirring rate of 300-800 rpm, and a stirring time preferably of 1-2 hours.

[0018] As a specific embodiment of the present invention, in step S2, the mixing conditions include: a temperature of 25℃-50℃; mixing includes stirring, with a stirring rate of 300-800 rpm, and a stirring time preferably of 1-2 hours.

[0019] Thirdly, the present invention provides the application of the low pour point high overload transformer oil described in the first aspect or the low pour point high overload transformer oil prepared by the preparation method described in the second aspect in the field of low temperature operating conditions.

[0020] All of the above-mentioned raw materials used in this invention can be prepared in-house or purchased commercially; this invention does not impose any particular limitations on them.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. The low pour point, high overload transformer oil of the present invention incorporates 60N base oil after urea dewaxing, which can effectively reduce the pour point of the product and improve product performance through the optimization of the base oil.

[0023] 2. The low pour point, high overload transformer oil of the present invention can provide insulation protection for rural power grids that are put into operation in a cold state at low temperatures.

[0024] 3. The low pour point, high overload transformer oil of the present invention improves product performance and reduces production costs by mixing base oils of different components. Detailed Implementation

[0025] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0026] Example 1

[0027] This embodiment provides a low pour point, high overload transformer oil and its preparation method, with specific details as follows:

[0028] S1: 899g of Sinopec Gaoqiao Hydrogenated HVI II2 Base Oil A and 90g of Sinopec Gaoqiao Hydrogenated 60N Base Oil B after urea dewaxing were stirred evenly at 30°C and a stirring rate of 800rpm to obtain the first mixture.

[0029] S2: Add 2.5g T501, 0.05g high-temperature phenolic antioxidant methyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate and 0.1g anti-gas evolution agent benzyltoluene to the first mixture obtained in step S1, and stir evenly at 800 rpm at 40°C to obtain low pour point high overload transformer oil 1.

[0030] Example 2

[0031] This embodiment provides a low pour point, high overload transformer oil and its preparation method, with specific details as follows:

[0032] S1: 850g of Maoming Petrochemical hydrotreated HVI II2 base oil A and 150g of Maoming Petrochemical hydrotreated 60N base oil B after urea dewaxing were stirred evenly at 25°C and a stirring rate of 500rpm to obtain the first mixture.

[0033] S2: Add 3.0g T501, 0.1g high-temperature phenolic antioxidant methyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate and 0.5g anti-gas evolution agent benzyltoluene to the first mixture obtained in step S1, and stir evenly at 800 rpm at 50°C to obtain low pour point high overload transformer oil 2.

[0034] Example 3

[0035] This embodiment provides a low pour point, high overload transformer oil and its preparation method, with specific details as follows:

[0036] S1: 940g of Yanshan Petrochemical hydrotreated HVI II2 base oil A and 60g of Yanshan Petrochemical hydrotreated 60N base oil B after urea dewaxing were stirred evenly at 35°C and a stirring rate of 300rpm to obtain the first mixture.

[0037] S2: Add 2.8g T501, 0.1g high-temperature phenolic antioxidant methyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate and 0.4g anti-gas evolution agent benzyltoluene to the first mixture obtained in step S1, and stir evenly at 800 rpm at 40°C to obtain low pour point high overload transformer oil 3.

[0038] Example 4

[0039] This embodiment provides a low pour point, high overload transformer oil and its preparation method, with specific details as follows:

[0040] S1: 880g of Maoming Petrochemical hydrotreated HVI II2 base oil A and 119g of Sinopec Gaoqiao hydrotreated 60N base oil B after urea dewaxing were stirred evenly at 30°C and a stirring rate of 500rpm to obtain the first mixture.

[0041] S2: Add 2.8g T501, 0.1g high-temperature phenolic antioxidant methyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate and 0.4g anti-gas evolution agent benzyltoluene to the first mixture obtained in step S1, and stir evenly at 800 rpm at 40°C to obtain low pour point high overload transformer oil 4.

[0042] Comparative Example 1

[0043] Transformer oil base oil produced according to the base oil in invention application number 201810891342.5 "A non-cycloalkyl high overload transformer oil base oil and its preparation method" was mixed with 2.8g T501, 0.1g high-temperature phenolic antioxidant methyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate and 0.4g anti-gas evolution agent benzyltoluene, and stirred evenly to obtain the transformer oil of Comparative Example 1.

[0044] Comparative Example 2

[0045] The transformer oil with the best performance in the invention patent application No. 201611139060.7, "A High Overload Transformer Oil and Its Preparation Process", is used as the transformer oil of Comparative Example 2.

[0046] Test case

[0047] The low pour point and high overload transformer oils obtained in Examples 1-4 of this invention and the transformer oils in Comparative Examples 1-2 were tested according to GB2536 "Unused Mineral Insulating Oils for Electrical Fluid Transformers and Switches". The results are shown in Table 1.

[0048] Table 1. Experimental results of Examples 1-4 and Comparative Examples 1-2

[0049]

[0050]

[0051] Through testing, the low pour point and high overload transformer oils of Examples 1-4 of this invention have excellent low-temperature performance and are suitable for the Northwest and Northeast regions. Due to the extremely low winter temperatures, they meet the requirements for low-temperature cold-state commissioning.

[0052] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values ​​that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 50-90, in this specification it means specifically listing values ​​such as 51-89, 52-88… and 69-71 and 70-71, etc. For non-integer values, it may be appropriately considered that a unit is 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0053] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A low pour point high overload transformer oil, characterized by, Its preparation components include base oil and additives; The base oil is composed of base oil A and base oil B, and the mass ratio of base oil A to base oil B is 85-88:11.

9. The base oil A is Maoming Petrochemical hydrotreated HVI II2 base oil; the base oil B is Sinopec Gaoqiao hydrotreated 60N base oil after urea dewaxing treatment; The additives include antioxidant T501, high-temperature phenolic antioxidant, and anti-gas evolution agent. The amount of antioxidant T501 added is 0.20%-0.35 wt% of the low pour point high overload transformer oil. The high-temperature phenolic antioxidant is methyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate, and its added amount is 0.005%-0.01 wt% of the low pour point high overload transformer oil. The anti-gas evolution agent is benzyltoluene, and its added amount is 0.01%-0.05 wt% of the low pour point high overload transformer oil.

2. A process for the preparation of a low pour point high overload transformer oil as claimed in claim 1, characterized in that, Includes the following steps: S1: Mix base oil A and base oil B evenly to obtain the first mixture; S2: Add additives to the first mixture obtained in step S1 and mix evenly to obtain the low pour point high overload transformer oil.

3. The preparation method according to claim 2, characterized in that, In step S1, the mixing conditions include: a temperature of 25℃-50℃; and mixing including stirring at a speed of 300-800 rpm.

4. The preparation method according to claim 3, characterized in that, In step S1, the stirring time is 1 to 2 hours.

5. The preparation method according to any one of claims 2-4, characterized in that, In step S2, the mixing conditions include: a temperature of 25-50°C; and mixing including stirring at a speed of 300-800 rpm.

6. The preparation method according to claim 5, characterized in that, In step S2, the stirring time is 1 to 2 hours.

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