A natural ester insulating oil and a method and application for preparing the natural ester insulating oil by using cottonseed oil

Abstract

The application discloses natural ester insulating oil and a method and application for preparing the natural ester insulating oil by using cottonseed oil, wherein the cottonseed oil is heated to 60-70 DEG C, an adsorbent I is added, and stirring adsorption is carried out at 60-70 DEG C, and then filtration is carried out; the filtrate after filtration is heated to 90-100 DEG C, an adsorbent II is added, and secondary deep vacuum constant-temperature adsorption is carried out at 90-100 DEG C, and then filtration is carried out; the filtrate after filtration is subjected to water removal treatment, and the natural ester insulating oil is obtained. The adsorbent I is composed of kaolin, calcium oxide and magnesium carbonate, and the adsorbent II is composed of branched amylopectin, graphene oxide and porous Al2O3; by controlling the adsorbent components, adsorption temperature and adding time, the application of the cottonseed oil in the natural ester insulating oil is realized, the adsorption performance is stable, and unnecessary pollution to the oil is avoided. The natural ester insulating oil is applied to a transformer, the food safety problem caused by excessive consumption of the cottonseed oil is solved, the added value of the cottonseed oil is improved, and the development direction of green low-carbon transformation is met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of natural ester insulating oil, and particularly relates to a natural ester insulating oil and a method and application for preparing the natural ester insulating oil from cottonseed oil. BACKGROUND

[0002] The natural ester insulating oil is obtained by converting plant oil through a series of purification processes, has the characteristics of high ignition point, low flammability, good water resistance, can be quickly degraded in nature, is environment-friendly, and can replace traditional mineral insulating oil.

[0003] At present, the natural ester insulating oil is mainly prepared from soybean-based natural ester insulating oil by modifying refined soybean oil. Cottonseed oil is a traditional edible oil with a long history, and is more inexpensive than soybean oil. However, the cottonseed oil directly pressed from cotton seeds contains a large amount of gossypol, which is toxic to the human body when consumed in excess, and needs to be deeply processed, which increases the cost and inhibits its application in the food field.

[0004] At present, there is no technology for deeply processing cottonseed oil into natural ester insulating oil. There are three technical difficulties in the process of preparing natural ester insulating oil from cottonseed oil. (1) The proportion of monoesters and phenolic substances in cottonseed oil is relatively high, which makes the pour point of cottonseed oil relatively high, usually above-10 DEG C. A lower pour point directly leads to a great reduction in the starting performance of a transformer at low temperatures when the cottonseed oil is used as insulating oil. (2) The fatty acid chain of the triglyceride in cottonseed oil is too long, and the long fatty acid chain increases the viscosity of cottonseed oil. The kinematic viscosity of cottonseed oil is above 60 m2 / s at 40 DEG C. Both indicators are higher than the requirements of natural ester transformer insulating oil. A higher kinematic viscosity is not conducive to the heat dissipation of the insulating layer of a transformer, and thus affects the operation of the transformer and even causes accidents. (3) Cottonseed oil contains a large amount of polar substances. When the polar substances in insulating oil are too much, the voltage resistance grade of the insulating oil is reduced. The voltage resistance limit of cottonseed oil is about 55 kV, which meets the corresponding requirements of insulating oil, but the proportion of polar substances needs to be further reduced to improve the voltage resistance grade of the insulating oil.

[0005] Therefore, it is of great significance to utilize cottonseed oil and process it into natural ester insulating oil. SUMMARY

[0006] In view of the technical problems in the prior art that cottonseed oil is applied to natural ester insulating oil, the application provides a natural ester insulating oil and a method and application for preparing the natural ester insulating oil from cottonseed oil, and the natural ester insulating oil meeting the standard requirements is obtained through twice adsorption filtration.

[0007] The application is achieved by the following technical scheme.

[0008] A method for preparing natural ester insulating oil by using cottonseed oil, comprising the following steps:

[0009] (1) the cottonseed oil is heated to 60~70℃, and an adsorbent I is added, and the adsorption is stirred at 60~70℃, and then filtered;

[0010] (2) the filtrate after filtering in step (1) is heated to 90~100℃, an adsorbent II is added, and the second deep vacuum constant temperature adsorption is carried out at 90~100℃, and then filtered;

[0011] (3) the filtrate after filtering in step (2) is subjected to water removal treatment, and natural ester insulating oil is obtained.

[0012] Further, in step (1), the adsorbent I is a compound of kaolin, calcium oxide and magnesium carbonate with a mass ratio of 2~5:3~7:1~3; in step (2), the adsorbent II is a compound of branched starch, graphene oxide and porous Al2O3 with a mass ratio of 1:0.5~1:2.

[0013] Further, in step (1), the particle size of the adsorbent I is 200~400 meshes; in step (2), the particle size of the adsorbent II is 600~800 meshes.

[0014] Further, in step (1), the adding amount of the adsorbent I is 5~8% of the mass of the cottonseed oil; in step (2), the adding amount of the adsorbent II is 2~4% of the mass of the cottonseed oil.

[0015] Further, in step (1), the adsorption time is 120~180 min; in step (2), the vacuum constant temperature adsorption time is 90~150 min.

[0016] Further, in step (2), the vacuum degree of the vacuum constant temperature adsorption is 0.05~0.1 MPa.

[0017] Further, in step (3), the water removal treatment method is vacuum drying, and the vacuum degree is 0.01~0.05 MPa.

[0018] Further, in step (1), the cottonseed oil is cottonseed oil directly pressed out from cottonseed.

[0019] In the present application, the natural ester insulating oil prepared by the above preparation method.

[0020] In the present application, the natural ester insulating oil prepared by the above preparation method is applied in a transformer.

[0021] The present application has the following beneficial effects:

[0022] The adsorbent I in the application is composed of kaolin, calcium oxide and magnesium carbonate, the calcium oxide can adsorb polar substances and reduce the acid value, and the kaolin and the magnesium carbonate can realize the preliminary adsorption of impurities, large particle substances, polar molecules and sol in the cottonseed oil through synergistic effect; the adsorbent II is composed of branched amylose, graphene oxide and porous Al2O3, the pour point, the viscosity and the acid value of the cottonseed oil are further reduced through secondary deep vacuum constant temperature adsorption, the deep removal of various impurities in the cottonseed oil is realized, and the natural ester insulating oil meeting the standard requirements and having stable properties is obtained, and the natural ester insulating oil is not prone to produce precipitates and suspensions.

[0023] The application of the cottonseed oil in the preparation of the natural ester insulating oil is realized through controlling the components of the adsorbent, the adsorption temperature and the adding time, the components of the adsorbent are used in cooperation, the adsorption performance is stable, unnecessary pollution to the oil is avoided, and new impurities are not introduced into the oil while the impurities are removed.

[0024] The natural ester insulating oil prepared from the cottonseed oil is biodegradable, which is not only beneficial to solving the food safety problem caused by excessive consumption of the cottonseed oil, provides a new rationalized industrial application route for the cottonseed oil, greatly improves the added value of the cottonseed oil, and effectively prevents environmental pollution, sewage discharge and cost reduction through replacing the traditional acid-base preparation method with the physical adsorption method, so that the development direction of green low-carbon transformation is met. DETAILED DESCRIPTION

[0025] The above content of the application is further described in detail through the following examples, but this should not be understood as the range of the above subject matter of the application being limited to the following examples only, and all the technologies realized based on the above content of the application belong to the range of the application.

[0026] The cottonseed oil in the embodiment of the application is the cottonseed oil directly pressed out of cottonseed, the breakdown voltage of the cottonseed oil is 20KV, the moisture content is 500mg / kg, the dielectric loss factor test (tan delta) (90℃) is 0.8, the pour point is-5℃, the acid value is 0.5mgKOH / g, the density is 0.93kg / m2, and the 40℃ kinematic viscosity is 70.

[0027] Example 1

[0028] (1) 500g of cottonseed oil is heated to 65℃, 30g of adsorbent I (a compound of kaolin, calcium oxide and magnesium carbonate with a mass ratio of 3:5:2, and the particle size is 200-400 mesh) is added, stirring and adsorbing at 65℃ for 150min, and then filtering;

[0029] (2) The filtrate after filtering in step (1) is heated to 100℃, 20g of adsorbent II (a compound of amylopectin, graphene oxide and porous Al2O3 with a mass ratio of 1:1:2 and a particle size of 600-800 mesh) is added, and secondary deep vacuum constant temperature adsorption (vacuum degree of 0.08 MPa) is carried out at 100℃ for 120 min, and then filtered;

[0030] (3) The filtrate after filtering in step (2) is vacuum dried at a vacuum degree of 0.05 MPa to obtain natural ester insulating oil.

[0031] Example 2

[0032] (1) 500g of cottonseed oil is heated to 60℃, 40g of adsorbent I (a compound of kaolin, calcium oxide and magnesium carbonate with a mass ratio of 2:3:1 and a particle size of 200-400 mesh) is added, and stirring adsorption is carried out at 60℃ for 180 min, and then filtered;

[0033] (2) The filtrate after filtering in step (1) is heated to 100℃, 15g of adsorbent II (a compound of amylopectin, graphene oxide and porous Al2O3 with a mass ratio of 1:1:2 and a particle size of 600-800 mesh) is added, and secondary deep vacuum constant temperature adsorption (vacuum degree of 0.05 MPa) is carried out at 100℃ for 150 min, and then filtered;

[0034] (3) The filtrate after filtering in step (2) is vacuum dried at a vacuum degree of 0.05 MPa to obtain natural ester insulating oil.

[0035] Example 3

[0036] (1) 500g of cottonseed oil is heated to 70℃, 28g of adsorbent I (a compound of kaolin, calcium oxide and magnesium carbonate with a mass ratio of 5:7:3 and a particle size of 200-400 mesh) is added, and stirring adsorption is carried out at 70℃ for 140 min, and then filtered;

[0037] (2) The filtrate after filtering in step (1) is heated to 90℃, 20g of adsorbent II (a compound of amylopectin, graphene oxide and porous Al2O3 with a mass ratio of 1:0.8:2 and a particle size of 600-800 mesh) is added, and secondary deep vacuum constant temperature adsorption (vacuum degree of 0.1 MPa) is carried out at 90℃ for 90 min, and then filtered;

[0038] (3) The filtrate after filtering in step (2) is vacuum dried at a vacuum degree of 0.05 MPa to obtain natural ester insulating oil.

[0039] Comparative Example 1

[0040] (1) 500 g of cottonseed oil was warmed to 100°C, 30 g of adsorbent I (a composite of kaolin, calcium oxide and magnesium carbonate with a mass ratio of 3:5:2, and a particle size of 200-400 mesh) and 20 g of adsorbent II (a composite of amylopectin, graphene oxide and porous Al2O3 with a mass ratio of 1:1:2, and a particle size of 600-800 mesh) were added, and vacuum constant temperature adsorption was carried out at 100°C for 150 min, and then filtered;

[0041] (2) The filtrate obtained in step (1) was vacuum dried at a vacuum degree of 0.05 MPa to obtain natural ester insulating oil.

[0042] Comparative Example 2

[0043] (1) 500 g of cottonseed oil was warmed to 65°C, 30 g of adsorbent I (a composite of kaolin, calcium oxide and magnesium carbonate with a mass ratio of 3:5:2, and a particle size of 200-400 mesh) was added, and vacuum constant temperature adsorption was carried out at 65°C for 150 min, and then filtered;

[0044] (2) The filtrate obtained in step (1) was warmed to 100°C, 20 g of adsorbent I (a composite of kaolin, calcium oxide and magnesium carbonate with a mass ratio of 3:5:2, and a particle size of 200-400 mesh) was added, and vacuum constant temperature adsorption was carried out at 100°C for 120 min, and then filtered;

[0045] (3) The filtrate obtained in step (2) was vacuum dried at a vacuum degree of 0.05 MPa to obtain natural ester insulating oil.

[0046] Comparative Example 3

[0047] (1) 500 g of cottonseed oil was warmed to 65°C, 30 g of adsorbent I (a composite of kaolin, calcium oxide and magnesium carbonate with a mass ratio of 3:5:2, and a particle size of 200-400 mesh) was added, and vacuum constant temperature adsorption was carried out at 65°C for 150 min, and then filtered;

[0048] (2) The filtrate obtained in step (1) was added with 20 g of adsorbent II (a composite of amylopectin, graphene oxide and porous Al2O3 with a mass ratio of 1:1:2, and a particle size of 600-800 mesh), and vacuum constant temperature adsorption was carried out at 65°C for 120 min, and then filtered;

[0049] (3) The filtrate obtained in step (2) was vacuum dried at a vacuum degree of 0.05 MPa to obtain natural ester insulating oil.

[0050] Performance Test

[0051] 1. The natural ester insulating oils prepared in Examples 1-3 and Comparative Examples 1-3 were used as samples, and the following tests were carried out, and the test results are shown in Table 1 below:

[0052] (1) Appearance: visual inspection;

[0053] (2) Breakdown voltage test (2.5mm) kV: GB / T 507;

[0054] (3) Moisture test mg / kg: GB / T 7600;

[0055] (4) Dielectric loss factor test (tan delta) (90℃): GB / T 5654;

[0056] (5) Pour point test ℃: GB / T 3535;

[0057] (6) Acid value test (in terms of KOH) mg / g: IEC 62021-3;

[0058] (7) Density (20℃) kg / m 3 : GB / T 1884;

[0059] (8) Corrosive sulfur test: GB / T 25961;

[0060] (9) 40℃ kinematic viscosity test: GB / T 265.

[0061] Table 1 Natural ester insulating oil performance test table

[0062]

[0063] 2. The natural ester insulating oil prepared in Example 1 is applied to a transformer, and its insulation performance, applied voltage withstand test, induced voltage withstand test, no-load loss and no-load current test, temperature rise performance test are tested;

[0064] The basic parameters of the transformer are as follows: product model: S22-M-1000 / 10; rated voltage ratio: 10±2×2.5 / 0.4KV; connection group: Dyn11; cooling method: ONAN; rated frequency: 50Hz; phase number: 3 phases; insulation level: high voltage, power frequency: 35KV, impulse: 75 / 85 (KV); low voltage: power frequency: 5KV; performance parameters: P0=665W Pĸ=7415W, Uĸ=4.5%, I0=1%.

[0065] The test results are shown in Tables 2-6, respectively, indicating that the natural ester insulating oil prepared by the application can be applied to a transformer.

[0066] Table 2 Insulation performance test results (insulation resistance requirement ≥1000MΩ, qualified)

[0067]

[0068] Table 3 Overvoltage test results

[0069]

[0070] Table 4 Induction overvoltage test results

[0071]

[0072] Table 5 No-load loss and no-load current test results

[0073]

[0074] Table 6 Temperature rise test results

[0075] .

Claims

1. A method for producing natural ester insulating oil using cottonseed oil, characterized by, The method comprises the following steps: (1) heating cottonseed oil to 60-70 DEG C, adding adsorbent I, stirring adsorption at 60-70 DEG C, and filtering; the adsorbent I is a compound of kaolin, calcium oxide and magnesium carbonate with a mass ratio of 2-5:3-7:1-3; (2) heating the filtrate after step (1) to 90-100 DEG C, adding adsorbent II, and performing secondary deep vacuum constant temperature adsorption at 90-100 DEG C, and filtering; the adsorbent II is a compound of branched amylose, graphene oxide and porous Al2O3 with a mass ratio of 1:0.5-1:2; (3) performing water removal treatment on the filtrate after step (2) to obtain natural ester insulating oil.

2. The method for preparing natural ester insulating oil using cottonseed oil according to claim 1, characterized in that, The particle size of the adsorbent I in step (1) is 200-400 mesh; the particle size of the adsorbent II in step (2) is 600-800 mesh.

3. The method for preparing natural ester insulating oil using cottonseed oil according to claim 1, characterized in that, The adding amount of the adsorbent I in step (1) is 5-8% of the mass of the cottonseed oil; the adding amount of the adsorbent II in step (2) is 2-4% of the mass of the cottonseed oil.

4. The method for preparing natural ester insulating oil using cottonseed oil according to claim 1, characterized in that, The adsorption time in step (1) is 120-180 min; the vacuum constant temperature adsorption time in step (2) is 90-150 min.

5. The method for preparing natural ester insulating oil using cottonseed oil according to claim 1, characterized in that, The vacuum degree of the vacuum constant temperature adsorption in step (2) is 0.05-0.1 MPa.

6. The method for preparing natural ester insulating oil using cottonseed oil according to claim 1, characterized in that, The water removal treatment method in step (3) is vacuum drying, and the vacuum degree is 0.01-0.05 MPa.

7. The method for preparing natural ester insulating oil using cottonseed oil according to claim 1, characterized in that, The cottonseed oil in step (1) is cottonseed oil directly pressed from cottonseeds.

8. Natural ester insulating oil prepared by the method of any one of claims 1-7.

9. Application of the natural ester insulating oil of claim 8 in a transformer.

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