Production process of extra-high voltage transformer oil

Abstract

The application discloses a production process of extra-high voltage transformer oil, through three hydrogenation devices with different pressures, the composition of refined oil products meets the characteristic requirements of naphthenic base oil, and indexes are superior to the GB2536-2011 'Electrical Fluids - Mineral Insulating Oils for Transformers and Switchgear (Special) - Unused' standard, and the production process can also be customized according to special requirements of users on some indexes, so that the extra-high voltage transformer with a voltage of 750KV or above can be operated and used. According to the development trend of clean and environment-friendly products, the high-pressure hydrogenation refining is adopted, and the treatment process of matched precision cutting and online dehydration and degassing is adopted, so that the production process has the advantages of flexible product adjustment, excellent stability, clean and friendly production environment and the like.

Description

Technical Field

[0001] This invention relates to the field of transformer oil application technology, and in particular to a production process for ultra-high voltage transformer oil. Background Technology

[0002] Transformer oil is a fractionation product of petroleum, its main components being alkanes, cycloalkanes, saturated hydrocarbons, and aromatic unsaturated hydrocarbons. It is primarily used in transformers, capacitors, and rheostats as an insulating medium, for arc suppression, and for heat dissipation. Based on the operating characteristics of transformer oil, it is required to possess excellent electrical properties, strong oxidation stability, excellent low-temperature fluidity, high-temperature safety performance, and low levels of impurities such as acids, alkalis, sulfur, and ash. Therefore, transformer oil must be a product of deep refining of petroleum fractions.

[0003] Ultra-high voltage transformer oil has stricter technical requirements than ordinary transformer oil, which are reflected in higher flash point, breakdown voltage, oxidation stability, etc. Traditional processing technology mostly adopts medium-pressure hydrogenation refining process, and the products generally adopt ordinary distillation technology. Its disadvantages include: (1) the product has a wide distillation range, and there is a lack of adjustment means to meet the flash point requirements and maintain good low-temperature fluidity; (2) the impurity content, especially the aromatic content, is relatively high. In the refining process, it is often necessary to use white clay refining process, which is not environmentally friendly, and the waste white clay needs to be treated as hazardous waste.

[0004] Based on the trend of clean and environmentally friendly product development, this invention adopts high-pressure hydrogenation refining and is equipped with precision cutting and online dehydration and degassing processes, which have the advantages of flexible product adjustment, excellent stability, and a clean and friendly production environment. Summary of the Invention

[0005] The purpose of this invention is to provide a production process for ultra-high voltage transformer oil that addresses traditional production methods. The process involves refining the oil through a three-stage hydrogenation unit at different pressures, and optimizing the carbon chain structure of the refined oil according to cycloalkyl characteristics requirements. This achieves a cycloalkane content of over 60% in the base oil, thus realizing the cycloalkyl characteristics of the ultra-high voltage transformer oil.

[0006] A production process for ultra-high voltage transformer oil includes the following steps:

[0007] S1. The Chunfeng crude oil feedstock is subjected to hydrodeacidification treatment. The reactor is subjected to hydrodeacidification reaction at a hydrogen pressure of 6.0~6.5Mpa and a reaction temperature of 320~360℃ to obtain No.1 refined oil.

[0008] S2. The No. 1 refined oil obtained from S1 is subjected to high-pressure hydrotreating. The reactor is subjected to deep hydrotreating reaction at a hydrogen pressure of 17.5-20.0 MPa and a reaction temperature of 300-350℃ to obtain No. 2 refined oil.

[0009] S3. The No. 2 refined oil obtained from S2 is put into medium-pressure hydroisomerization treatment. The reactor is subjected to hydroisomerization reaction at a hydrogen pressure of 10~12Mpa and a reaction temperature of 300~350℃. Then it is put into the post-refining reactor, where the isomerization reaction product is hydrorefined at 250~290℃ to obtain No. 3 refined oil.

[0010] S4. Add the No. 3 refined oil obtained in S3 to the fractionation and cutting device, and obtain No. 4 refined oil by removing the light components at the head and the heavy components at the tail.

[0011] The No. 4 refined oil obtained from S5 and S4 is added to a vacuum packed degassing tower. After removing moisture and dissolved gases by nitrogen stripping, transformer oil base oil is obtained.

[0012] The transformer oil base oils obtained from S6 and S5 are mixed with antioxidants in the tank area to obtain ultra-high voltage transformer oil products.

[0013] Preferably, S1 uses RS-2000 catalyst with a hydrogen partial pressure of 6.0~6.5MPa; S2 uses RL-2+RLF-2 catalyst with a hydrogen partial pressure of 17.5~20MPa; and S3 uses RLF-20 catalyst with a hydrogen partial pressure of 10~12MPa.

[0014] Preferably, the ultra-high voltage transformer oil product has a naphthenic acid (CN) content of not less than 60%, a pour point of less than -50°C, and a minimum cold-state commissioning temperature of -40°C.

[0015] Preferably, S4 employs a two-tower distillation technology to precisely remove light and heavy components, enabling flexible control over the distillation range of transformer oil base oil, with a base oil flash point greater than 140℃.

[0016] Preferably, structured packing is used in S5, the drying tower operating temperature is 50~55℃, the vacuum degree is 70kPa, and it is designed to withstand 10Nm 3 / t oil ratio control for stripping nitrogen.

[0017] Preferably, S5 uses online vacuum degassing technology to control the base oil water content to be less than 20 mg / kg and the total hydrocarbon content in dissolved gases to be less than 5 μL / L.

[0018] Preferably, in S6, a cyclic addition method is used to control the antioxidant content within the range of 0.08% to 0.4% by mass.

[0019] The advantages of this invention: The overall quality of the ultra-high voltage transformer oil exceeds the requirements of GB2536-2011 "Unused Mineral Insulating Oil for Electrical Fluid Transformers and Switches" standard. Its flash point is higher than 140℃, pour point is lower than -50℃, breakdown voltage (2.5mm) is higher than 60KV, dielectric loss factor (90℃) is lower than 0.0003, moisture content is lower than 20mg / kg, and total hydrocarbon content in dissolved gases is less than 5μL / L. The product has a CN value greater than 60%, exhibits good naphthenic characteristics, and has low aromatic hydrocarbon content. The production process and product performance are clean and user-friendly. Detailed Implementation

[0020] S1. The feedstock oil of Chunfeng crude oil (taken from Chunfeng Oilfield in Xinjiang) undergoes hydrodeacidification treatment. The reactor carries out the hydrodeacidification reaction at a hydrogen pressure of 6.3 MPa and a reaction temperature of 335℃ to obtain No. 1 refined oil;

[0021] S2. The No. 1 refined oil obtained from S1 is subjected to high-pressure hydrogenation treatment. The reactor is subjected to deep hydrogenation reaction at a hydrogen pressure of 18.0 MPa and a reaction temperature of 340°C to obtain No. 2 refined oil.

[0022] S3. The No. 2 refined oil obtained in S2 is added to a medium-pressure hydroisomerization treatment reactor. The hydroisomerization reaction is carried out in the reactor at a hydrogen pressure of 10.5 MPa and a reaction temperature of 342°C. Then, it enters the post-refining reactor at a reaction temperature of 294°C to hydrorefine the isomerization product and obtain No. 3 refined oil.

[0023] S4. Add the No. 3 refined oil obtained in S3 to the fractionation and cutting device, where the top temperature of the head removal column is 240℃ and the top temperature of the tail removal column is 265℃. By removing the light components at the head and the heavy components at the tail, No. 4 refined oil is obtained, with a distillation range of 266~329℃.

[0024] The No. 4 refined oil obtained from S5 and S4 is added to a vacuum packed degassing tower. The feed temperature is controlled at 50~55℃. After removing moisture and dissolved gases by nitrogen stripping, transformer oil base oil is obtained.

[0025] The transformer oil base oils obtained from S6 and S5 are blended and diluted with trace amounts of antioxidants in the tank area to obtain ultra-high voltage transformer oil products.

[0026] Implementation Case 2

[0027] S1. The Chunfeng crude oil feedstock undergoes hydrodeacidification treatment. The hydrodeacidification reaction is carried out in the reactor at a hydrogen pressure of 6.3 MPa and a reaction temperature of 336℃ to obtain No. 1 refined oil;

[0028] S2. The No. 1 refined oil obtained from S1 is subjected to high-pressure hydrogenation treatment. The reactor is subjected to deep hydrogenation reaction at a hydrogen pressure of 18.5 MPa and a reaction temperature of 335°C to obtain No. 2 refined oil.

[0029] S3. The No. 2 refined oil obtained in S2 is added to the medium-pressure hydroisomerization treatment. The reactor is subjected to hydroisomerization reaction at a hydrogen pressure of 10.5 MPa and a reaction temperature of 334°C. Then it enters the post-refining reactor and is hydrorefined at 290°C to obtain No. 3 refined oil.

[0030] S4. Add the No. 3 refined oil obtained in S3 to the fractionation and cutting device, where the top temperature of the head removal column is 255℃ and the top temperature of the tail removal column is 260℃. By removing the light components at the head and the heavy components at the tail, a No. 4 refined oil with a narrower distillation range (distillation range 292~309℃) is obtained.

[0031] The No. 4 refined oil obtained from S5 and S4 is added to a vacuum packed degassing tower. After removing moisture and dissolved gases by nitrogen stripping, transformer oil base oil is obtained.

[0032] The transformer oil base oils obtained from S6 and S5 are blended and diluted with trace amounts of antioxidants in the tank area to obtain ultra-high voltage transformer oil products.

[0033] <Experimental Test Data>

[0034] The product from Case 1 was commissioned to Xi'an Thermal Power Research Institute for testing. Its overall quality exceeded the requirements of GB2536-2011 "Unused Mineral Insulating Oil for Electrical Fluid Transformers and Switches (Special)" standard, meeting the requirements for use in ultra-high voltage transformer oil. The test results are shown in Appendix 1.

[0035] The product from Case 2 was commissioned to the East China branch of Lubricating Oil for testing. The overall quality was better than the requirements of GB2536-2011 "Unused Mineral Insulating Oil for Electrical Fluid Transformers and Switches (Special)" standard. The viscosity was further reduced at low temperature (-30℃), meeting the requirements for use in ultra-high voltage transformer oil. The test results are shown in Tables 1 and 2.

[0036] Table 1. Routine Performance Testing of UHV Transformer Oil

[0037]

[0038] Table 2 Oxidation Stability Analysis of Transformer Oil

[0039]

[0040] The product meets the requirements of GB2536-2011 "Unused Mineral Insulating Oil for Electrical Fluid Transformers and Switches (Special)" standard, and can be further customized with reference to relevant electrical industry safety standards. Through flexible and precise control of the distillation range, the product's intrinsic indicators such as flash point, viscosity, low-temperature viscosity, and pour point can meet customized requirements. The product's production process is stable, resulting in consistent quality. It has low aromatic content, is free of harmful polycyclic aromatic hydrocarbons, and possesses excellent oxidation resistance. The product quality reaches or exceeds the level of similar imported products.

[0041] The above embodiments are only for illustrating the technical solutions and features of the present invention, and are intended to enable those skilled in the art to implement them better. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention are within the scope of protection of the present invention. The parts not described in detail are prior art.

Claims

1. A process for the production of extra high voltage transformer oil, characterized in that It comprises the following steps: S1, the spring wind crude oil raw oil is subjected to hydrodeacidification treatment, a hydrodeacidification reactor is subjected to hydrodeacidification reaction under hydrogen pressure of 6.0-6.5 Mpa and reaction temperature of 320-360 DEG C, and 1# refined oil is obtained; S2, the 1# refined oil obtained in S1 is subjected to high-pressure hydroprocessing, a high-pressure hydroprocessing reactor is subjected to deep hydroprocessing reaction under hydrogen pressure of 17.5-20.0 Mpa and reaction temperature of 300-350 DEG C, and 2# refined oil is obtained; S3, the 2# refined oil obtained in S2 is subjected to medium-pressure hydroisomerization treatment, a medium-pressure hydroisomerization reactor is subjected to hydroisomerization reaction under hydrogen pressure of 10-12 Mpa and reaction temperature of 300-350 DEG C, then enters a post-refining reactor, and the isomerization reaction product is subjected to hydrofining under 250-290 DEG C, and 3# refined oil is obtained; S4, the 3# refined oil obtained in S3 is added to a fractionation cutting device, and light components and heavy components at the head and tail are cut off, and 4# refined oil is obtained; S5, the 4# refined oil obtained in S4 is added to a vacuum packed degassing tower, and after nitrogen stripping to remove water and soluble gas, transformer oil base oil is obtained; S6, the transformer oil base oil obtained in S5 is added with an antioxidant in a tank area and uniformly blended, and a UHV transformer oil product is obtained; S1 adopts RS-2000 catalyst; S2 adopts RL-2+RLF-2 catalyst; and S3 adopts RLF-20 catalyst. The UHV transformer oil product has a naphthene content CN value of not less than 60%, a pour point of less than -50 DEG C, and a minimum cold operation temperature of -40 DEG C. S4 adopts two-tower distillation technology, and light components and heavy components are accurately removed, so that the distillation range of the transformer oil base oil is flexibly controlled, and the flash point of the transformer oil base oil is greater than 140 DEG C.

2. The process for producing extra high voltage transformer oil as claimed in claim 1, wherein In S5, the structured packing is used, the operating temperature is 50-55℃, the vacuum degree is 70kpa, and the stripping nitrogen is controlled according to the ratio of 10Nm 3 / t oil.

3. The process for producing extra high voltage transformer oil as claimed in claim 1, wherein S5 controls the water content of the transformer oil base oil to be less than 20 mg / kg and the total hydrocarbon content in the soluble gas to be less than 5 mu L / L through online vacuum degassing technology.

4. The process for producing extra high voltage transformer oil as claimed in claim 1, wherein S6 controls the antioxidant addition content in the range of 0.08%-0.4% mass fraction.

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