A preparation process and device for preparing transformer insulating oil using plant cottonseed oil

Abstract

The present invention relates to the technical field of transformer insulating oil preparation, and discloses a preparation process and device for preparing transformer insulating oil using plant cottonseed oil. The steps include: raw material preparation, first adsorption treatment, second adsorption treatment, vacuum degassing treatment, ultrasonic oscillation treatment, and high-voltage electrostatic treatment; it is prepared by physical methods, avoiding the possible pollution and adverse effects on the performance of insulating oil caused by chemical methods; through the coordination of multiple steps such as two adsorption treatments, vacuum degassing, ultrasonic oscillation, and high-voltage electrostatic treatment, impurities, moisture, free fatty acids, etc. in cottonseed oil are effectively removed, improving the purity and stability of the insulating oil, ensuring excellent insulating oil performance, meeting the use requirements of transformer insulating oil, and having the advantages of environmental protection and sustainable development.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer insulating oil preparation, and specifically to a preparation process and device for preparing transformer insulating oil using plant cottonseed oil. Background Art

[0002] Insulating oil is usually made by adding antioxidants to deeply refined lubricating oil base oil and is widely used in high-voltage electrical equipment such as transformers, circuit breakers, oil-filled cables, power capacitors, and bushings. Insulating oil impregnates and protects transformers, cables, capacitors, etc., preventing air or moisture from entering and ensuring reliable insulation. Insulating oil also cools power equipment such as transformers. The hot oil is cooled by a radiator and then returns to the transformer body, causing the insulating oil in the box to circulate and cool to keep the transformer temperature within a certain range. In addition to being an insulating medium, insulating oil also serves as an arc-extinguishing medium, preventing the spread of the arc and promoting the rapid extinction of the arc.

[0003] Transformer insulating oil can be mainly divided into several categories such as mineral insulating oil, plant insulating oil, silicone insulating oil, synthetic ester insulating oil, and modified insulating oil. However, mineral insulating oil is prone to leakage and pollution and has poor fire resistance, while silicone insulating oil, synthetic ester insulating oil, and modified insulating oil have high manufacturing costs. Plant insulating oil has increasingly become a research hotspot in the industry. Currently, the preparation of plant insulating oil mainly uses raw materials such as rapeseed oil and camellia seed oil, and there is little research on using cottonseed oil as a raw material. Moreover, the acid value and other indicators of cottonseed oil are relatively high, and using a single alkali catalyst cannot avoid problems such as poisoning of active sites in the transesterification reaction.

[0004] Chinese Patent CN106635432A discloses a method for producing plant insulating oil using swill oil. The main raw material is refined swill oil, the reaction raw materials are ethanol, the catalyst is KOH or NaOH, the neutralizing reagent is phosphoric acid. By transesterifying swill oil and ethanol, the viscosity of swill oil is reduced and impurities in swill oil are removed to obtain high-purity fatty acid ethyl ester. Then, using fatty acid ethyl ester as the main raw material, the reaction raw material is pentaerythritol, the catalyst is monobutyltin oxide, the filter is diatomaceous earth, clay, activated carbon, and nitrogen is used as the protective gas. By reacting fatty acid ethyl ester and pentaerythritol, high-quality plant insulating oil is obtained through a refining process.

[0005] Chinese Patent CN113817525A discloses a preparation method of natural ester insulating oil. The raw material oil including recycled oil is degummed to remove phospholipids, reducing the influence of phospholipids on the pour point and facilitating the separation of subsequent fatty acids in each component. Then, transesterification reaction is carried out, and after impurity removal, mixed fatty acid monoesters are obtained. Through solvent crystallization separation, various high-purity single-component fatty acid monoesters are obtained. Then, transesterification reaction is carried out with glycerol under the action of a catalyst to obtain corresponding various high-purity single-component triglycerides. After mixing, a natural ester insulating oil with a low pour point and freezing point, capable of being used in low-temperature regions, small kinematic viscosity, and high fluidity and heat dissipation capacity is obtained.

[0006] In the above patents, chemical process treatment methods are all adopted.

[0007] With the development of China's power industry, higher requirements are put forward for the performance and environmental protection of transformer insulating oil. Traditional mineral insulating oil has potential harm problems such as limited resources and non-degradable environmental pollution.

[0008] With the emphasis on environmental protection and sustainable development, using natural oils and fats to prepare insulating oil has become a research hotspot. However, natural oil cottonseed oil contains impurities, moisture, etc., which will affect its insulating performance. Therefore, an effective physical preparation method is needed. Summary of the Invention

[0009] Aiming at the deficiencies of the prior art, the present invention provides a preparation process and device for preparing transformer insulating oil using plant cottonseed oil, which has the advantages of being prepared by physical methods, avoiding pollution and adverse effects on the performance of insulating oil that may be brought by chemical methods.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] A preparation process for preparing transformer insulating oil using plant cottonseed oil, the steps of which include:

[0012] Raw material preparation: Select cottonseed oil as the basic raw material;

[0013] The first adsorption treatment: Place the cottonseed oil in a heatable device, slowly heat it to 60-70 °C, add the first adsorbent, and use a stirring device to stir, so that the first adsorbent is fully integrated with the cottonseed oil to adsorb impurities, moisture and part of free fat, etc. in it;

[0014] After the stirring ends, filter through a filter screen with a filtration accuracy of 5-10 μm to obtain the filtrate after the first treatment.

[0015] Second adsorption treatment: Transfer the filtrate after the first treatment to another reactor with vacuum and heating functions, heat it up to 90 - 100 °C, add the second adsorbent, place the filtrate after adding the second adsorbent in a device with a vacuum degree of 0.08 - 0.09 Mpa, and conduct the second deep vacuum constant temperature adsorption treatment with a constant temperature adsorption time of 60 - 90 minutes;

[0016] Vacuum degassing treatment: Filter the liquid after the second adsorption treatment through a vacuum suction filtration device with a filtration accuracy of 1 - 5 μm, place the filtered cottonseed oil in a vacuum degassing device with a vacuum degree of 50 - 150 Pa, maintain the temperature at 60 - 70 °C, and the treatment time is 2 - 4 hours to allow the dissolved gases in the cottonseed oil to escape fully and reduce the potential harm of gas content to the insulation performance;

[0017] Ultrasonic oscillation treatment: Place the degassed cottonseed oil in an ultrasonic treatment device, set the ultrasonic frequency to 20 - 50 KHz, the power to 300 - 600 W, and the treatment time to 15 - 30 minutes. Utilize the cavitation effect of ultrasonic waves to break up the small aggregates in the oil and improve the uniformity and stability of the oil;

[0018] High - voltage electrostatic treatment: Pass the cottonseed oil treated by ultrasonic waves through a high - voltage electrostatic field with an electrostatic field intensity of 3 - 8 kV / cm, so that the charged particles in the oil move and aggregate directionally under the action of the electric field, further remove impurities and optimize the microstructure in the oil, and enhance the insulation performance.

[0019] Preferably: The first adsorbent is composed of kaolin, alumina and magnesium sulfate mixed in a ratio of 2:1:1, and the dosage is 1 - 3% of the mass of cottonseed oil.

[0020] Preferably: The second adsorbent is composed of amylose, graphene oxide and porous Al 2 O 3 mixed in a ratio of 2:1:3, and the dosage is 0.5 - 1.5% of the mass of the filtrate.

[0021] Preferably: In the high - voltage electrostatic treatment step, the breakdown voltage is not less than 35 kV, the dielectric loss factor does not exceed 0.2% at 20 - 40 °C, and the moisture content is lower than 50 ppm.

[0022] A preparation device for preparing transformer insulating oil from plant cottonseed oil, including a first adsorption treatment tank, a second adsorption treatment tank, a vacuum degassing tower, an ultrasonic oscillation box and a high - voltage electrostatic processor tank, and each component is connected in sequence through pipelines;

[0023] It further includes a mixing mechanism, and the mixing mechanism is arranged inside the first adsorption treatment tank and the second adsorption treatment tank. The mixing mechanism is used for stirring the adsorbent and cottonseed oil inside the first adsorption treatment tank and the second adsorption treatment tank;

[0024] The mixing mechanism includes an outer shaft rod and an output shaft. The output shaft is fixedly connected inside the outer shaft rod. The first adsorption treatment tank and the second adsorption treatment tank include a tank bottom plate. The outer shaft rod is rotatably connected to the top of the tank bottom plate. The top of the output shaft is hinged with a first stirring rod. The bottom of the first stirring rod is fixedly connected with an auxiliary scraper. The top of the rod body of the first stirring rod is fixedly connected with a deflector plate. A variable frequency motor is arranged outside the output shaft.

[0025] Preferably: A regulator is fixedly connected below the tank bottom plate. An inner cavity and an outer cavity are formed inside the regulator. A connecting cavity is formed between the inner cavity and the outer cavity. A feeding pipe is fixedly connected to the outside of the inner cavity. The feeding pipe is externally connected to an adsorbent supply device. A shunt pipe is fixedly connected to the outside of the inner cavity. The end of the shunt pipe is fixedly connected with a discharge pipe. The discharge port of the discharge pipe is arranged above the tank body.

[0026] Preferably: A control valve ring is movably connected inside the connecting cavity. The end of the control valve ring extending outside the regulator is fixedly connected with a connecting ring. A regulating rod is rotatably connected to the outside of the connecting ring.

[0027] Preferably: The regulating rod is slidably connected through the inside of the outer shaft rod. A return spring is arranged between the regulating rod and the outer shaft rod. The regulating rod is in a "7" shape. The end of the regulating rod located inside the tank body is slidably connected with the first stirring rod. A positioning ring is arranged at one end of the regulating rod located at the bottom of the tank bottom plate. The regulating rod is rotatably connected through the positioning ring and the connecting ring.

[0028] Preferably: A counterweight ball is fixedly connected to the outside of the first stirring rod. The auxiliary scraper is attached to the top of the tank bottom plate.

[0029] Preferably: The auxiliary scraper is horizontally deflected. An extension plate is slidably connected inside the auxiliary scraper. A pressure spring is arranged between the extension plate and the auxiliary scraper.

[0030] Advantages of the present invention:

[0031] 1. The preparation process of using plant cottonseed oil to prepare transformer insulating oil is prepared by physical methods, avoiding the possible pollution and adverse effects on the performance of insulating oil caused by chemical methods; through the coordination of multiple steps such as two adsorption treatments, vacuum degassing, ultrasonic oscillation, and high-voltage electrostatic treatment, impurities, moisture, free fatty acids, etc. in cottonseed oil are effectively removed, improving the purity and stability of the insulating oil, ensuring excellent performance of the insulating oil, meeting the use requirements of transformer insulating oil, and having the advantages of environmental protection and sustainable development.

[0032] 2. The preparation device for transformer insulating oil using plant cottonseed oil, through the combined use of the first stirring rod and the auxiliary scraper, has different forms under the conditions of high-speed rotation and low-speed rotation. Under high-speed rotation, the first stirring rod and the auxiliary scraper expand outwards, effectively improving the stirring effect and quickly dispersing the adsorbent. Under low-speed rotation, the scraper fits the bottom plate of the tank, and the low rotation speed reduces energy consumption and avoids affecting the oil quality due to over-stirring. At the same time, the scraper can effectively prevent the adsorbent from sinking to the bottom.

[0033] 3. The preparation device for transformer insulating oil using plant cottonseed oil, through the inclined setting of the guide plate and the auxiliary scraper, makes the cottonseed oil form a spiral upward or downward flow path, increasing the contact frequency and contact effect between the cottonseed oil and the adsorbent. When the auxiliary scraper fits the bottom plate of the tank, the auxiliary scraper pushes the cottonseed oil to diffuse and flow outwards, further improving the treatment effect on the precipitated adsorbent, and at the same time facilitating the discharge of the cottonseed oil through the discharge pipe.

[0034] 4. The preparation process and device for transformer insulating oil using plant cottonseed oil, through the cooperation of the auxiliary scraper and the extension plate, when the auxiliary scraper expands outwards, the extension plate increases the cross-section of the auxiliary scraper in the horizontal direction, thereby improving the stirring and guiding effects of the auxiliary scraper, enabling the cottonseed oil to form a stable upward spiral flow path. When the auxiliary scraper fits the bottom plate of the tank, the extension plate retracts into the auxiliary scraper, reducing the cross-section of the auxiliary scraper in the horizontal direction, reducing the mixing and stirring damping, and at the same time avoiding damaging the oil quality due to over-stirring, ensuring the mixing and adsorption effect of the adsorbent and the cottonseed oil. Description of the Drawings

[0035] Figure 1 It is a schematic diagram of the overall equipment of the preparation device of the present invention;

[0036] Figure 2 It is a schematic diagram of the mixing mechanism of the present invention;

[0037] Figure 3 It is a schematic diagram of the connection of the outer shaft rod, output shaft, first stirring rod, regulating rod and regulator of the present invention;

[0038] Figure 4 It is a schematic diagram of the connection of the first stirring rod and the auxiliary scraper of the present invention;

[0039] Figure 5 It is a schematic diagram of the connection of the regulating rod, connecting ring and control valve ring of the present invention;

[0040] Figure 6 It is a schematic diagram of the sectional state of the regulator of the present invention;

[0041] Figure 7 For the present invention Figure 4 Enlarged schematic diagram of part A.

[0042] In the figure: 1, the first adsorption treatment tank; 2, the second adsorption treatment tank; 3, the vacuum degassing tower; 4, the ultrasonic oscillation box; 5, the high-voltage electrostatic processor tank; 6, the mixing mechanism; 61, the outer shaft rod; 62, the output shaft; 63, the first stirring rod; 64, the auxiliary scraper; 641, the extension plate; 642, the pressure spring; 65, the deflector plate; 66, the counterweight ball; 67, the regulator; 68, the inner cavity body; 69, the outer cavity body; 610, the connection cavity; 611, the feed pipe; 612, the shunt pipe; 613, the control valve ring; 614, the connection ring; 615, the control rod; 616, the discharge pipe; 617, the tank bottom plate; 618, the discharge pipe; 619, the return spring. Detailed implementation manners

[0043] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0044] A preparation process for preparing transformer insulating oil by using plant cottonseed oil, the steps of which include:

[0045] Raw material preparation: Select cottonseed oil as the basic raw material;

[0046] The first adsorption treatment: Place the cottonseed oil in a heatable device, slowly heat it up to 60-70 °C, add the first adsorbent, and use a stirring device to stir and treat it to make the first adsorbent fully blend with the cottonseed oil and adsorb impurities, moisture and some free fat, etc. therein;

[0047] After the stirring ends, filter through a filter screen with a filtration accuracy of 5-10 μm to obtain the filtrate after the first treatment

[0048] The second adsorption treatment: Transfer the filtrate after the first treatment to another reaction kettle with a vacuum heating function, heat it up to 90-100 °C, add the second adsorbent, place the filtrate after adding the second adsorbent in a device with a vacuum degree of 0.08-0.09 Mpa, and perform a second deep vacuum constant temperature adsorption treatment, and the constant temperature adsorption time is 60-90 minutes;

[0049] Vacuum degassing treatment: Filter the liquid after the second adsorption treatment through a vacuum filtration device with a filtration accuracy of 1-5 μm, place the filtered cottonseed oil in a vacuum degassing device with a vacuum degree of 50-150 Pa, maintain the temperature at 60-70 °C, and the treatment time is 2-4 hours to make the dissolved gas in the cottonseed oil fully escape and reduce the potential harm of gas content to the insulation performance;

[0050] Ultrasonic oscillation treatment: Place the degassed cottonseed oil in an ultrasonic treatment device, set the ultrasonic frequency to 20 - 50 KHz, the power to 300 - 600 W, and the treatment time to 15 - 30 minutes. Utilize the cavitation effect of ultrasonic waves to break up the tiny aggregates in the oil and improve the uniformity and stability of the oil;

[0051] High - voltage electrostatic treatment: Pass the cottonseed oil treated by ultrasonic waves through a high - voltage electrostatic field with an electrostatic field strength of 3 - 8 kV / cm, so that the charged particles in the oil move and aggregate directionally under the action of the electric field, further removing impurities and optimizing the microstructure in the oil, and enhancing the insulation performance.

[0052] Among them, the first adsorbent is composed of kaolin, alumina, and magnesium sulfate mixed in a ratio of 2:1:1, and the dosage is 1 - 3% of the mass of the cottonseed oil.

[0053] Among them, the second adsorbent is composed of starch, graphene oxide, and porous Al 2 O 3 mixed in a ratio of 2:1:3, and the dosage is 0.5 - 1.5% of the mass of the filtrate.

[0054] Among them, in the high - voltage electrostatic treatment step, the breakdown voltage is not less than 35 kV, the dielectric loss factor at 20 - 40 °C does not exceed 0.2%, and the moisture content is lower than 50 ppm.

[0055] In the adsorption treatment step, the first adsorption uses a mixed adsorbent of kaolin, alumina, and magnesium sulfate, and the second adsorption uses a mixed adsorbent of starch, graphene oxide, and porous Al 2 O 3 mixed adsorbent. Utilize the porous structure or active characteristics of these adsorbents. Under certain conditions such as temperature and vacuum, they can adsorb impurities, moisture, acidic substances, etc. in the cottonseed oil, and filter out the adsorbent after adsorbing impurities through a filter screen, so as to achieve the purpose of purification.

[0056] During vacuum degassing treatment, utilize the vacuum environment and appropriate temperature to make the dissolved gases in the cottonseed oil overflow under low pressure, while ultrasonic oscillation treatment uses the cavitation effect to break up tiny aggregates and further optimize the microstructure. Through the synergistic effect of the above steps, the performance of the cottonseed oil is improved.

[0057] Prepared by physical methods, it avoids the pollution and adverse effects on the performance of insulating oil that may be brought about by chemical methods.

[0058] Through multiple steps of cooperation such as two adsorption treatments, vacuum degassing, ultrasonic oscillation, and high-voltage electrostatic treatment, impurities, moisture, free fatty acids, etc. in cottonseed oil are effectively removed, improving the purity and stability of the insulating oil, ensuring excellent performance of the insulating oil, meeting the usage requirements of transformer insulating oil, and having the advantages of environmental protection and sustainable development.

[0059] Example 1: 1. Raw material preparation: Select 1000 g of high-quality cottonseed oil

[0060] 2. First adsorption treatment: Place the cottonseed oil in a heatable device, heat it to 60 °C, add 10 g of adsorbent (accounting for 1% of the mass of cottonseed oil) composed of kaolin, calcium oxide, and magnesium sulfate in a ratio of 2:1:1. During the addition of the adsorbent, use a relatively high rotation speed (300 - 400 r / min) to quickly disperse the adsorbent; after the adsorption reaction proceeds for 10 minutes, reduce the rotation speed (150 - 200 r / min) to reduce energy consumption and avoid affecting the oil quality due to excessive stirring, continuously stir for 30 minutes, and then filter with a filter screen with a filtration accuracy of 5 μm.

[0061] 3. Second adsorption treatment: Transfer the filtrate to a vacuum heating reaction kettle, heat it to 90 °C, add 5 g of adsorbent (accounting for 0.5% of the mass of cottonseed oil) composed of starch, graphene oxide, and porous Al 2 O 3 in a ratio of 2:1:3, and adsorb at a constant temperature for 60 minutes under a vacuum of 0.08 Mpa, and then filter with a vacuum filtration device with a filter screen accuracy of 1 μm.

[0062] 4. Vacuum degassing treatment: Place the filtered cottonseed oil in a vacuum degassing device with a vacuum of 50 Pa and a temperature of 60 °C for 2 hours.

[0063] 5. Ultrasonic oscillation treatment: Place the cottonseed oil in an ultrasonic treatment device, set the frequency to 20 KHz and the power to 300 W, and treat for 15 minutes.

[0064] High-voltage electrostatic field treatment: Pass the cottonseed oil through a high-voltage electrostatic field with an intensity of 3 kV / cm.

[0065] Example 2; 1. Raw material preparation: 2000 g of high-quality cottonseed oil

[0066] 2. First adsorption treatment: Heat it to 65 °C in a heatable device, add 40 g of the above adsorbent (accounting for 2% of the mass of cottonseed oil). During the addition of the adsorbent, use a relatively high rotation speed (350 - 420 r / min) to quickly disperse the adsorbent; after the adsorption reaction proceeds for 15 minutes, reduce the rotation speed (200 - 250 r / min) to reduce energy consumption and avoid affecting the oil quality due to excessive stirring, continuously stir for 45 minutes, and filter with a filter screen with a filtration accuracy of 8 μm.

[0067] 3. Second adsorption treatment: The filtrate is heated to 95 °C in a reaction kettle, 20 g of adsorbent is added (accounting for 1% of the cottonseed oil), and it is adsorbed at a constant temperature for 75 minutes under a vacuum of 0.085 Mpa, and then filtered with a vacuum filtration device with a filtration accuracy of 3 μm.

[0068] 4. Vacuum degassing treatment: The cottonseed oil is treated at a vacuum of 100 Pa and a temperature of 65 °C for 3 hours.

[0069] 5. Ultrasonic oscillation treatment: The ultrasonic frequency is 30 KHz, the power is 450 W, and the treatment time is 20 minutes.

[0070] 6. High-voltage electrostatic field treatment: Through a high-voltage electrostatic field with an intensity of 5 kV / cm.

[0071] Implementation Case 3: 1. Raw material preparation: 1500 g of high-quality cottonseed oil

[0072] 2. First adsorption treatment: Heat to 70 °C, add 30 g of adsorbent (accounting for 2% of the cottonseed oil mass), and during the addition of the adsorbent, use a relatively high rotation speed (380 - 450 r / min) to quickly disperse the adsorbent; after the adsorption reaction proceeds for 15 minutes, reduce the rotation speed (200 - 300 r / min) to reduce energy consumption and avoid affecting the oil quality due to excessive stirring, continue stirring for 60 minutes, and filter with a filter screen with a filtration accuracy of 10 μm.

[0073] 3. Second adsorption treatment: Heat the filtrate to 100 °C, add 18 g of adsorbent (accounting for 1.2% of the cottonseed oil mass), and adsorb at a constant temperature for 90 minutes under a vacuum of 0.09 MPa, and then filter with a vacuum filtration device with a filtration accuracy of 5 μm.

[0074] 4. Vacuum degassing treatment: Treat at a vacuum of 150 Pa and a temperature of 70 °C for 4 hours.

[0075] 5. Ultrasonic oscillation treatment: The ultrasonic frequency is 50 KHz, the power is 600 w, and the treatment time is 30 minutes.

[0076] High-voltage electrostatic field treatment: Through a high-voltage electrostatic field with an intensity of 8 kV / cm.

[0077] Implementation Case 4: 1. Raw material preparation: 3000 g of high-quality cottonseed oil.

[0078] 2. First adsorption treatment: Heat to 68 °C, add 60 g of adsorbent (accounting for 2% of the cottonseed oil mass), and during the addition of the adsorbent, use a relatively high rotation speed (350 - 420 r / min) to quickly disperse the adsorbent; after the adsorption reaction proceeds for 12 minutes, reduce the rotation speed (180 - 280 r / min) to reduce energy consumption and avoid affecting the oil quality due to excessive stirring, continue stirring for 50 minutes, and filter with an 8 μm filter screen.

[0079] 3. Second adsorption treatment: The filtrate is heated to 98 °C, 30 g of adsorbent (1% of the cottonseed oil amount) is added, and it is adsorbed at a constant temperature under a vacuum of 0.088 MPa for 80 minutes, and then filtered with a 4-μm vacuum filtration device.

[0080] 4. Vacuum degassing treatment: It is treated at a vacuum degree of 120 Pa and a temperature of 68 °C for 3.5 hours.

[0081] 5. Ultrasonic oscillation treatment: The frequency is 40 KHz, the power is 500 W, and the treatment is carried out for 25 minutes.

[0082] 6. High-voltage electrostatic field treatment: Through a high-voltage electrostatic field with an intensity of 6 kV / cm.

[0083] Basic numerical situation table of Examples 1, 2, 3, and 4:

[0084]

[0085] Performance parameters of cottonseed insulating oil

[0086]

[0087] As can be seen from the above table, the various indicators of the cottonseed insulating oil physically prepared by the present invention are excellent. Among them, the breakdown voltage (70 kV, 2.5 mm), flash point (302 °C) and fire point (330 °C) indicators are far better than those of mineral oil, and the use safety is good; and the low-temperature performance is excellent (pour point -37 °C).

[0088] Furthermore, in the above embodiments, in the preparation process of using plant cottonseed oil to prepare transformer insulating oil, it is carried out through a preparation device for using plant cottonseed oil to prepare transformer insulating oil. Specifically:

[0089] Reference Figures 1-6 , a preparation device for using plant cottonseed oil to prepare transformer insulating oil, includes a first adsorption treatment tank 1, a second adsorption treatment tank 2, a vacuum degassing tower 3, an ultrasonic oscillation box 4 and a high-voltage electrostatic processor tank 5, and each component is connected in sequence through pipelines;

[0090] Among them, the first adsorption treatment, the second adsorption treatment, the vacuum degassing treatment, the ultrasonic oscillation treatment and the high-voltage electrostatic treatment are carried out in sequence in the first adsorption treatment tank 1, the second adsorption treatment tank 2, the vacuum degassing tower 3, the ultrasonic oscillation box 4 and the high-voltage electrostatic processor tank 5.

[0091] The device further includes a mixing mechanism 6. The mixing mechanism 6 is arranged inside the first adsorption treatment tank 1 and the second adsorption treatment tank 2, and the mixing mechanism 6 is used for stirring the adsorbent and the cottonseed oil inside the first adsorption treatment tank 1 and the second adsorption treatment tank 2;

[0092] The mixing mechanism 6 includes an outer shaft rod 61 and an output shaft 62. The output shaft 62 is fixedly connected inside the outer shaft rod 61. The first adsorption treatment tank 1 and the second adsorption treatment tank 2 include a tank bottom plate 617. The outer shaft rod 61 is rotatably connected to the top of the tank bottom plate 617. The top of the output shaft 62 is hinged with a first stirring rod 63. The bottom of the first stirring rod 63 is fixedly connected with an auxiliary scraper 64. The top of the rod body of the first stirring rod 63 is fixedly connected with a flow guide plate 65. A variable frequency motor is arranged outside the output shaft 62.

[0093] It should be noted that the variable frequency motor can flexibly adjust the stirring speed according to the filtrate volume, adsorbent characteristics and reaction stage. During the addition of the adsorbent, a higher speed (300 - 450 r / min) is adopted to quickly disperse the adsorbent. After the adsorption reaction proceeds for a period of time, the speed is reduced (150 - 300 r / min) to reduce energy consumption and avoid affecting the oil quality due to excessive stirring.

[0094] It should be noted that a flow guide plate 65 is arranged outside the first stirring rod 63. The flow guide plate 65 is inclined. During the rotation of the flow guide plate 65 with the first stirring rod 63, the flow guide plate 65 makes the cottonseed oil form a spiral upward or downward flow path, increasing the contact frequency and contact effect between the cottonseed oil and the adsorbent.

[0095] Wherein, a regulator 67 is fixedly connected below the tank bottom plate 617. An inner cavity 68 and an outer cavity 69 are formed inside the regulator 67. A connecting cavity 610 is formed between the inner cavity 68 and the outer cavity 69. A feeding pipe 611 is fixedly connected to the outside of the inner cavity 68. The feeding pipe 611 is externally connected to an adsorbent supply device. A shunt pipe 612 is fixedly connected to the outside of the inner cavity 68. The end of the shunt pipe 612 is fixedly connected with a discharge pipe 616. The discharge port of the discharge pipe 616 is arranged above the tank body.

[0096] It should be noted that when adding the adsorbent, the adsorbent is first added into the inner cavity 68 through the feeding pipe 611. Under the action of pressure, the adsorbent enters the outer cavity 69 through the connecting cavity 610, and then is dispersed and flows to a number of discharge pipes 616 through the shunt pipe 612.

[0097] By dispersing and spraying the adsorbent, the adsorbent is dispersed and slowly mixed into the vegetable cottonseed oil, thereby avoiding the phenomenon of agglomeration of the adsorbent inside the cottonseed oil, ensuring the preliminary mixing effect of the adsorbent and the cottonseed oil, facilitating the subsequent mixing and adsorption effect, and further improving the adsorption effect on the cottonseed oil.

[0098] Wherein, a control valve ring 613 is movably connected inside the connecting cavity 610. The outer end of the control valve ring 613 extending to the outside of the regulator 67 is fixedly connected with a connecting ring 614. A regulating rod 615 is rotatably connected to the outside of the connecting ring 614.

[0099] Among them, the control rod 615 runs through and is slidably connected inside the outer shaft rod 61. A return spring 619 is arranged between the control rod 615 and the outer shaft rod 61. The control rod 615 is in a "7" shape. The end of the control rod 615 located inside the tank body is slidably connected to the first stirring rod 63. A positioning ring is arranged at one end of the control rod 615 at the bottom of the tank bottom plate 617. The control rod 615 is rotationally connected through the positioning ring and the connecting ring 614.

[0100] Among them, a counterweight ball 66 is fixedly connected to the outside of the first stirring rod 63, and the auxiliary scraper 64 is attached to the top of the tank bottom plate 617.

[0101] It should be noted that during the addition of the adsorbent, the variable-frequency motor controls the output shaft 62 to rotate at a high speed. The output shaft 62 drives the first stirring rod 63 to rotate at a high speed. Thus, under the action of centrifugal force, the first stirring rod 63 deflects upward. The first stirring rod 63 drives the control rod 615 to move upward. The control rod 615 drives the control valve ring 613 to move upward through the bottom connecting ring 614. Thereby, the outer cavity 69 and the connecting cavity 610 are communicated, and then the inner cavity 68 and the outer cavity 69 are communicated. Thereby, the adsorbent can enter the discharge pipe 616 through the outer cavity 69 and the shunt pipe 612 for dispersed addition of the adsorbent.

[0102] And during the high-speed stirring stage, the first stirring rod 63 expands outward, thereby effectively increasing the stirring range of the first stirring rod 63. And at this time, the auxiliary scraper 64 is laterally suspended inside the adsorption tank, achieving the effect of assisting in increasing the stirring effect and further improving the mixing effect of the initial contact between the adsorbent and the cottonseed oil.

[0103] During the mixing stage, the variable-frequency motor controls the output shaft 62 to reduce the rotation speed. The centrifugal force of the first stirring rod 63 and the counterweight ball 66 is reduced. Under the action of the return spring 619, the deflection amplitude of the first stirring rod 63 is reduced, making the auxiliary scraper 64 fit on the top of the tank bottom plate 617. Thereby, during the low-speed mixing and adsorption period, it can be ensured that the over-stirring damage to the oil quality can be avoided, and the auxiliary scraper 64 can effectively prevent the adsorbent from precipitating, further ensuring the mixing and adsorption effect of the adsorbent and the cottonseed oil.

[0104] Furthermore, the auxiliary scraper 64 is horizontally deflected. An extension plate 641 is slidably connected inside the auxiliary scraper 64. A pressure spring 642 is arranged between the extension plate 641 and the auxiliary scraper 64.

[0105] Through the deflection setting of the auxiliary scraper 64, when the first stirring rod 63 expands outwards, the auxiliary scraper 64 deflects outwards synchronously. At this time, the extension plate 641 extends outwards under the action of the pressure spring 642, thereby increasing the cross-section of the auxiliary scraper 64 and enhancing the stirring and mixing effect of the auxiliary scraper 64 on cottonseed oil. Moreover, due to the deflection setting of the auxiliary scraper 64, during the rotation of the auxiliary scraper 64, a spiral upward flow path of cottonseed oil is generated, further improving the mixing effect of the auxiliary scraper 64 on cottonseed oil.

[0106] Furthermore, when the first stirring rod 63 rotates at a low speed, the regulating rod 615 moves downward under the action of the return spring 619, and then the control valve ring 613 moves downward to cut off the connection cavity 610 and the outer cavity 69. At low-speed rotation, the adsorbent is no longer put in, and at the same time, at low-speed rotation, the mixing and adsorption effect of the adsorbent and cottonseed oil is ensured. When the regulating rod 615 moves downward, the first stirring rod 63 deflects downward, and at the same time, the auxiliary scraper 64 fits against the tank bottom plate 617. At this time, the extension plate 641 compresses the pressure spring 642 and retracts into the interior of the auxiliary scraper 64. Also, due to the inclined setting of the auxiliary scraper 64, the auxiliary scraper 64 pushes the cottonseed oil to flow outwards and diffuse, further improving the treatment effect on the precipitated adsorbent and facilitating the discharge of cottonseed oil through the discharge pipe 618.

[0107] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation device for preparing transformer insulating oil using plant cottonseed oil, characterized in that: It includes a first adsorption treatment tank, a second adsorption treatment tank, a vacuum degassing tower, an ultrasonic oscillation box and a high-voltage electrostatic treatment tank, and each component is connected in sequence through pipelines; It also includes a mixing mechanism, which is arranged inside the first adsorption treatment tank and the second adsorption treatment tank, and is used to stir the adsorbent and cottonseed oil inside the first adsorption treatment tank and the second adsorption treatment tank; The mixing mechanism includes an outer shaft and an output shaft, the output shaft is fixedly connected to the inside of the outer shaft, the first adsorption treatment tank and the second adsorption treatment tank include a tank bottom plate, the outer shaft is rotatably connected to the top of the tank bottom plate, the top of the output shaft is hinged with a first stirring rod, the bottom of the first stirring rod is fixedly connected to an auxiliary scraper, the top of the rod body of the first stirring rod is fixedly connected to a guide plate, and a variable frequency motor is arranged outside the output shaft; A regulator is fixedly connected to the bottom of the tank bottom plate, an inner cavity and an outer cavity are provided inside the regulator, a connecting cavity is provided between the inner cavity and the outer cavity, a feed pipe is fixedly connected to the outside of the inner cavity, the feed pipe is externally connected to an adsorbent supply device, a shunt pipe is fixedly connected to the outside of the inner cavity, a discharge pipe is fixedly connected to the end of the shunt pipe, and a discharge port of the discharge pipe is arranged above the tank body; The interior of the connecting cavity is movably connected with a control valve ring, the control valve ring extends to the outer end of the regulator and is fixedly connected with a connecting ring, and the outer end of the connecting ring is rotatably connected with a regulating rod; The regulating rod passes through and is slidably connected to the inside of the outer shaft rod, a reset spring is arranged between the regulating rod and the outer shaft rod, the regulating rod is in the shape of a "7", the end of the regulating rod located inside the tank body is slidably connected to the first stirring rod, a positioning ring is arranged at one end of the regulating rod located at the bottom of the tank bottom plate, and the regulating rod is rotatably connected through the positioning ring and the connecting ring.

2. The device for preparing transformer insulating oil by using plant cottonseed oil according to claim 1, characterized in that: A counterweight ball is fixedly connected to the outside of the first stirring rod, and the auxiliary scraper is attached to the top of the tank bottom plate.

3. The device for preparing transformer insulating oil by using plant cottonseed oil according to claim 1, characterized in that: The auxiliary scraper is arranged to be horizontally deflected, and an extension plate is slidably connected inside the auxiliary scraper, and a pressure spring is arranged between the extension plate and the auxiliary scraper.

4. A preparation process for the preparation device for preparing transformer insulating oil using plant cottonseed oil according to claim 1, characterized in that: The steps include: Raw material preparation: cottonseed oil is used as the basic raw material; Using the first adsorption treatment tank to perform adsorption treatment: placing the cottonseed oil in a heating device, slowly heating it to 60-70° C., adding the first adsorbent, and using a stirring device to perform stirring treatment to fully blend the first adsorbent with the cottonseed oil; The second adsorption treatment tank is used for the second adsorption treatment: the filtrate after the first adsorption treatment is transferred to another reactor with a vacuum heating function, heated to 90-100°C, and the second adsorbent is added. The filtrate after the second adsorbent is added is placed in a device with a vacuum degree of 0.08-0.09Mpa, and the second deep vacuum constant temperature adsorption treatment is carried out, and the constant temperature adsorption time is 60-90 minutes; Vacuum degassing treatment: The liquid subjected to the second adsorption treatment is filtered through a vacuum filtration device with a filtration accuracy of 1-5 μm, and the filtered cottonseed oil is placed in a vacuum degassing tower with a vacuum degree of 50-150 Pa, the temperature is maintained at 60-70°C, and the treatment time is 2-4 hours; Ultrasonic vibration treatment: Place the degassed cottonseed oil in an ultrasonic vibration box, set the ultrasonic frequency to 20-50KHz, the power to 300-600W, and the treatment time to 15-30 minutes; High-voltage electrostatic treatment: The cottonseed oil treated with ultrasound is passed through a high-voltage electrostatic processor tank with an electrostatic field strength of 3-8kV / cm, so that the charged particles in the oil move and aggregate in a directional manner under the action of the electric field.

5. A process for preparing transformer insulating oil using plant cottonseed oil according to claim 4, characterized in that: The first adsorbent is a mixture of kaolin, alumina and magnesium sulfate in a ratio of 2:1:1, and the amount used is 1-3% of the mass of cottonseed oil.

6. A process for preparing transformer insulating oil using plant cottonseed oil according to claim 4, characterized in that: The second adsorbent is a mixture of chain starch, graphene oxide and porous Al2O3 in a ratio of 2:1:3, and the amount used is 0.5-1.5% of the mass of the filtrate.

7. A process for preparing transformer insulating oil using plant cottonseed oil according to claim 4, characterized in that: In the high-voltage electrostatic treatment step, the breakdown voltage is not less than 35kV, the dielectric loss factor does not exceed 0.2% at 20-40°C, and the moisture content is less than 50ppm.

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