Method for producing anti-gassing component of transformer oil

Abstract

The invention relates to the technical field of petrochemical engineering, in particular to a method for producing an anti-gassing component of transformer oil. The method comprises the following steps: step 1, taking extract oil of transformer oil fraction hydrodeacidification oil as a raw material, carrying out extraction in a counter-current extraction tower by adopting a double-solvent extraction process to obtain solvent refined oil of the anti-gassing component of the transformer oil; and step 2, solvent refined oil of the anti-gassing component, wherein the base oil obtained by liquid phase denitrification and carclazyte refining is the anti-gassing component of the transformer oil. The anti-gassing component of the transformer oil prepared by the invention is low in basic nitrogen content, high in total content of monocyclic and bicyclic aromatic hydrocarbons, good in gassing property and excellent in oxidation stability.

Description

Technical Field:

[0001] The present invention relates to the technical field of petrochemical engineering, and particularly to a method for producing an anti-gassing component of transformer oil. Background Art:

[0002] Transformer oil, as an important insulating medium in power electrical equipment, plays roles such as heat dissipation, insulation, and arc extinction of transformers. With the development of the power industry and the improvement of the voltage levels of power transmission and transformation equipment, the demand for transformer oil is continuously increasing, and at the same time, the quality requirements are also continuously improving. Its performance is of great significance for the safe operation of transformers.

[0003] Special transformer oil for extra-high voltage transformers has higher requirements for anti-gassing performance. Research shows that under the action of a high-voltage electric field in transformer oil, straight-chain alkanes in the oil will release more hydrogen, naphthenes will release less hydrogen, and aromatics will absorb the hydrogen released by straight-chain alkanes and naphthenes. This property of aromatics is called anti-gassing property, and substances with this property are called anti-gassing additives. Gassing property is an important index in high-voltage transformer oil. Aromatics have good anti-gassing performance, but excessive aromatics, especially polycyclic aromatics, affect the oxidation stability of the product.

[0004] To improve the gassing property of transformer oil, Chinese Patent CN102676215A uses the solvent-refined extract oil of transformer oil or a mixed oil of it and the fraction of naphthenic-base transformer oil as raw materials, and through the processes of solvent refining - liquid-phase denitrification and clay refining, produces an anti-gassing additive, which has the problems of low aromatic content and poor anti-gassing property of the target product.

[0005] Chinese Patent CN 105087059B discloses an anti-gassing component of transformer oil and its preparation method. This method uses the solvent extract oil with a distillation range of 230 - 260°C as raw material, and through complex denitrification with a denitrifying agent and adsorption with an adsorbent, obtains a refined oil, which is the anti-gassing component of transformer oil. The anti-gassing component produced by this method has a limited addition amount due to its low flash point. Summary of the Invention:

[0006] The technical problem to be solved by the present invention is to provide a method for producing an anti-gassing component of transformer oil. The anti-gassing component of transformer oil prepared by this method has a low basic nitrogen content, a high total content of single-ring and double-ring aromatics, good gassing property, and excellent oxidation stability.

[0007] The technical solution adopted by the present invention is: A method for producing an anti-gassing component of transformer oil, which includes the following steps:

[0008] Step 1: Using the extract oil of the hydrogenated deacidified oil of transformer oil fraction as the raw material oil, it is carried out in a countercurrent extraction tower, adopting a double-solvent extraction process, namely the main solvent and the auxiliary solvent. After the main solvent is mixed with the raw material oil, it enters Extraction Tower I from the upper part. The auxiliary solvent is mixed with a part of the extract liquid at the bottom of Extraction Tower II and then enters Extraction Tower I from the lower part of Extraction Tower I. The remaining extract liquid of Extraction Tower II is mixed with the extract liquid of Extraction Tower I, and after recovering the main solvent, a secondary extract oil is obtained; the raffinate liquid at the top of Extraction Tower I is the raw material of Extraction Tower II and enters Extraction Tower II from the lower part. The main solvent enters Extraction Tower II from the upper part. The raffinate liquid obtained at the top of Extraction Tower II is used as the raw material of Extraction Tower III and enters Extraction Tower III from the lower part. The main solvent enters Extraction Tower III from the upper part. The raffinate liquid obtained at the top of Extraction Tower III can be recycled as the auxiliary solvent, and the extract liquid obtained at the bottom of Extraction Tower III is refined to obtain the solvent-refined oil of the anti-gassing component of transformer oil after recovering the main solvent;

[0009] Step 2: The solvent-refined oil of the anti-gassing component, after liquid-phase denitrification and clay refining, the obtained base oil is the anti-gassing component of transformer oil.

[0010] Furthermore, the main solvent is furfural; the auxiliary solvent is a base oil with a closed-cup flash point of not less than 135°C, a kinematic viscosity at 40°C of not more than 12.0 mm 2 / s, a pour point of not higher than -40°C, and a C A value of not more than 5%.

[0011] Furthermore, the extract oil of the hydrogenated deacidified oil of transformer oil fraction is the furfural-refined extract oil of naphthenic base 280°C - 330°C hydrogenated deacidified oil.

[0012] Furthermore, in Step 1, the top temperature of Extraction Tower I is 50°C - 60°C, the bottom temperature is 40°C, and the mass ratio of the main solvent entering Extraction Tower I to the raw material oil is 0.4 - 1.0:1, and the mass ratio of the auxiliary solvent entering Extraction Tower I to the raw material oil is 0.2 - 1.0:1.

[0013] Furthermore, in Step 1, the top temperature of Extraction Tower II is 60°C - 80°C, the bottom temperature is 40°C - 50°C, and the mass ratio of the main solvent entering Extraction Tower II to the raw material oil is 2.5 - 5.0:1.

[0014] Furthermore, in Step 1, the top temperature of Extraction Tower III is 80°C - 85°C, the bottom temperature is 50°C - 55°C, and the mass ratio of the main solvent entering Extraction Tower III to the raw material oil is 2.0 - 5.0:1.

[0015] Further, the denitrifying agent used in the liquid-phase denitrification in Step 2 is WQ-2 or WQ-3. The addition amount of the denitrifying agent is 0.3m%-0.8m% of the solvent-refined oil of the anti-gassing component. The operating conditions are a reaction temperature of 50-85°C and a reaction time of 30-40 minutes.

[0016] Further, the denitrifying agent is WQ-2.

[0017] Further, in the clay refining in Step 2, the addition amount of clay is 1m%-8m% of the solvent-refined oil of the anti-gassing component, the refining temperature is 100-130°C, and the refining time is 30-50 minutes.

[0018] The beneficial effects of the present invention are as follows: The anti-gassing component of the transformer oil prepared by the present invention has a low basic nitrogen content, a high total content of single-ring and double-ring aromatic hydrocarbons, good gassing properties, and excellent oxidation stability. Description of the Drawings:

[0019] The following further describes the present invention in detail with reference to the drawings and specific embodiments.

[0020] Figure 1 It is the process flow diagram of the present invention.

[0021] The labels therein are respectively represented as: 1, Extraction Tower I; 2, Extraction Tower II; 3, Extraction Tower III; 4, Main solvent of Extraction Tower I; 5, Feedstock oil; 6, Sub-solvent; 7, Raffinate at the top of Extraction Tower I; 8, Draw-off liquid at the bottom of Extraction Tower I; 9, Raffinate at the top of Extraction Tower II; 10, Draw-off liquid at the bottom of Extraction Tower II; 11, Part of the draw-off liquid of Extraction Tower II returned to Extraction Tower I; 12, Main solvent of Extraction Tower II; 13, Main solvent of Extraction Tower III; 14, Raffinate at the top of Extraction Tower III; 15, Draw-off liquid at the bottom of Extraction Tower III. Specific Embodiments:

[0022] Example 1

[0023] Using the furfural extraction oil of naphthenic (280 - 330) normal secondary deacidified oil as the feedstock, the properties are shown in Table 1. The refining conditions are as follows: the top temperature of Extraction Tower I is 60°C, the bottom temperature is 40°C, the mass ratio of the main solvent furfural entering Extraction Tower I to the feedstock is 0.4:1, the mass ratio of the auxiliary solvent entering Extraction Tower I to the feedstock is 0.2:1. After the main solvent and the feedstock are mixed, they enter Extraction Tower I from the upper part of the tower. The auxiliary solvent is mixed with a part of the extract from the bottom of Extraction Tower II and then enters Extraction Tower I from the lower part of the tower. The mass ratio of this part of the extract to the feedstock is 0.1:1. The remaining extracts from Extraction Tower II and the extracts from Extraction Tower I are mixed to recover the main solvent, and then the secondary extract oil is obtained; the raffinate at the top of Extraction Tower I is used as the feedstock for Extraction Tower II and enters Extraction Tower II from the lower part of the tower. The main solvent enters Extraction Tower II from the upper part of the tower. The raffinate obtained at the top of Extraction Tower II is used as the feedstock for Extraction Tower III and enters Extraction Tower III from the lower part of the tower. The main solvent enters Extraction Tower III from the upper part of the tower. The raffinate obtained at the top of Extraction Tower III can be recycled as the auxiliary solvent. The extract obtained at the bottom of Extraction Tower III is refined by recovering the main solvent to obtain the furfural-refined oil of the anti-gassing component of transformer oil; the operating conditions of Extraction Tower II are that the top temperature is 60°C, the bottom temperature is 40°C, and the mass ratio of the main solvent furfural entering Extraction Tower II to the feedstock is 2.0:1. The operating conditions of Extraction Tower III are that the top temperature is 85°C, the bottom temperature is 55°C, and the mass ratio of the main solvent furfural entering Extraction Tower III to the feedstock is 2.5:1.

[0024] The obtained furfural-refined oil is subjected to denitrification - clay refining. The denitrification refining conditions are as follows: the denitrifying agent is a commercially available product WQ-2, the addition amount is 0.3 mass%, the reaction temperature is 85°C, and the residence time is 30 minutes to obtain the denitrification-refined oil. Then, it is subjected to clay refining. The clay refining conditions are as follows: the clay addition amount is 5 mass%, the reaction temperature is 120°C, and the residence time is 50 minutes to obtain the clay-refined oil. The detailed operating conditions and product properties are shown in Table 3.

[0025] It can be seen from Table 3 that for the anti-gassing component of transformer oil produced in Example 1, the basic nitrogen content of the anti-gassing component of transformer oil is less than 1 μg / g, the total content of mono-ring and double-ring aromatics is 60.4%, the gas evolution property is less than -40 μL / min, the pour point is below -50°C, the polycyclic aromatic hydrocarbon content is less than 1.0%, and the oxidation stability measured by the SH / T0811 method shows that the total acid value is 0.1 mgKOH / g and the sludge is 0.08%, indicating that the oxidation stability of the prepared anti-gassing component of transformer oil is good.

[0026] Example 2

[0027] Using the furfural extraction oil of naphthenic (280 - 330) normal secondary deacidified oil as the feedstock, which is the same as that in Example 1, and adopting the same process as in Example 1. The specific test conditions and product properties are shown in Table 3.

[0028] As can be seen from Table 3: For the anti-gassing component of transformer oil produced in Example 2, the basic nitrogen content of the anti-gassing component of transformer oil is less than 1 μg / g, the total content of single-ring and double-ring aromatic hydrocarbons is 66.8%, the gassing property is less than -40 μL / min, the pour point is below -50 °C, the polycyclic aromatic hydrocarbon content is less than 1.0%, and for the oxidation stability measured by the SH / T0811 method, the total acid value is 0.3 mgKOH / g and the sludge is 0.12%, indicating that the oxidation stability of the prepared anti-gassing component of transformer oil is good.

[0029] Example 3

[0030] Using the furfural extraction oil of the naphthenic (280 - 330) normal secondary deacidified oil as the raw material oil, which is the same as that in Example 1, and adopting the same process as in Example 1, the specific test conditions and product properties are shown in Table 3.

[0031] As can be seen from Table 3: For the anti-gassing component of transformer oil produced in Example 3, the basic nitrogen content of the anti-gassing component of transformer oil is less than 1 μg / g, the total content of single-ring and double-ring aromatic hydrocarbons is 64.0%, the gassing property is less than -40 μL / min, the pour point is below -50 °C, the polycyclic aromatic hydrocarbon content is less than 1.0%, and for the oxidation stability measured by the SH / T0811 method, the total acid value is 0.2 mgKOH / g and the sludge is 0.11%, indicating that the oxidation stability of the prepared anti-gassing component of transformer oil is good.

[0032] Comparative Example 1

[0033] Using the furfural extraction oil of the naphthenic (280 - 330) normal secondary deacidified oil as the raw material oil, which is the same as that in Example 1, and adopting the conventional furfural extraction process, the specific test conditions and product properties are shown in Table 3.

[0034] Solvent furfural enters the extraction tower from the upper part of the extraction tower, the raw material oil enters the extraction tower from the lower part of the extraction tower, the raffinate obtained at the top is recovered of the solvent to obtain furfural refined oil, and the extract obtained at the bottom is recovered of the solvent to obtain secondary extract oil; the obtained furfural refined oil is subjected to denitrification - clay refining, and the detailed operating conditions and product properties are shown in Table 3.

[0035] As can be seen from Table 3: For the anti-gassing component of transformer oil produced, the basic nitrogen content of the anti-gassing component of transformer oil is less than 1 μg / g, the total content of single-ring and double-ring aromatic hydrocarbons is 58.0%, the gassing property is less than -22 μL / min, the pour point is below -50 °C, the polycyclic aromatic hydrocarbon content is less than 1.0%, and for the oxidation stability measured by the SH / T0811 method, the total acid value is 5.2 mgKOH / g and the sludge is 3.5%, indicating that the oxidation stability of the prepared anti-gassing component of transformer oil is not good.

[0036] Comparative Example 2

[0037] Using the furfural extract oil of the naphthenic (280 - 330) normal secondary deacidified oil as the feedstock, which is the same as that in Example 1, and adopting the conventional two-stage furfural extraction process. The specific test conditions and product properties are shown in Table 3.

[0038] Furfural enters the extraction tower 1 from the upper part, and the feedstock oil enters the extraction tower 1 from the lower part. The raffinate obtained at the top is used as the feedstock of extraction tower 2 and enters extraction tower 2 from the lower part. The solvent furfural enters extraction tower 2 from the lower part. After recovering the solvent from the raffinate at the top of extraction tower 2, furfural-refined oil is obtained, and after recovering the solvent from the extract obtained at the bottom of extraction tower 2, secondary extract oil is obtained; the obtained furfural-refined oil is subjected to denitrification - clay refining. The detailed operating conditions and product properties are shown in Table 3.

[0039] It can be seen from Table 3 that the anti-gassing component of the transformer oil produced has an alkaline nitrogen content of less than 1 μg / g, the total content of single-ring and double-ring aromatic hydrocarbons is 35.5%, the gas evolution property is less than -15 μL / min, the pour point is lower than -47 °C, the polycyclic aromatic hydrocarbon content is less than 1.0%, and the oxidation stability measured by the SH / T0811 method has a total acid value of 0.1 mgKOH / g and a sludge content of 0.07%, indicating that the prepared anti-gassing component of the transformer oil has good oxidation stability.

[0040] It can be seen from Examples 1 - 3 and Comparative Examples 1 - 2 that using the naphthenic normal secondary deacidified oil as the feedstock and adopting the method of the present invention to obtain furfural-refined oil, after liquid-phase denitrification - clay refining, the total content of single-ring and double-ring aromatic hydrocarbons in the product is greater than 60%, the gas evolution property is less than -40 μL / min, the pour point is lower than -50 °C, the polycyclic aromatic hydrocarbon content is less than 1.0%, and the oxidation stability is excellent, which can be used as a blending component to improve the gas evolution property of transformer oil; it can be seen from Comparative Example 1 that using the conventional furfural refining to obtain furfural-refined oil, after liquid-phase denitrification - clay refining, the total content of single-ring and double-ring aromatic hydrocarbons in the product is 42.9%, the gas evolution property is -22 μL / min, the gas evolution property and aromatic hydrocarbon content of the product are greatly reduced, and the alkaline nitrogen content of the anti-gassing component of the produced transformer oil is high, and the oxidation stability of the product is poor and cannot meet the requirements. It can be seen from Comparative Example 2 that using the furfural extract oil of the naphthenic normal secondary deacidified oil as the feedstock, after obtaining furfural-refined oil by two-stage furfural refining and then liquid-phase denitrification - clay refining, the total content of single-ring and double-ring aromatic hydrocarbons of the anti-gassing component of the obtained transformer oil is 35.5%, the gas evolution property is less than -11 μL / min, the pour point is -48 °C, the polycyclic aromatic hydrocarbon content is less than 1.0%, and the oxidation stability is excellent, but the gas evolution property and aromatic hydrocarbon content of the product are greatly reduced.

[0041] After adopting conventional single-stage and two-stage furfural refining and then liquid-phase denitrification-clay refining, it is impossible to obtain the anti-gassing component of transformer oil with the total content of monocyclic and bicyclic aromatic hydrocarbons greater than 60%, the gassing property less than -40 uL / min, the pour point lower than -50 °C, the polycyclic aromatic hydrocarbon content less than 1.0%, and excellent oxidation stability of the present invention.

[0042] Table 1 Properties of the feedstock oil (hydrofined and acid-removed oil of naphthenic 280-330 fraction furfural extract)

[0043]

[0044] Table 2 Properties of the co-solvent

[0045]

[0046]

[0047] Table 3 Process conditions of the examples and comparative examples

[0048]

[0049] It can be understood that the above specific description of the present invention is only for explaining the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those of ordinary skill in the art should understand that the present invention can still be modified or equivalently replaced to achieve the same technical effects; as long as the use requirements are met, they are all within the protection scope of the present invention.

Claims

1. A method for producing an anti-gassing component of transformer oil, characterized in that: The method includes the following steps: Step 1: Using the extract oil of the hydrodeacidified oil of transformer oil fraction as the feedstock, it is carried out in a countercurrent extraction tower, adopting a double-solvent extraction process, namely the main solvent and the secondary solvent. After the main solvent is mixed with the feedstock, it enters Extraction Tower I from the upper part. The secondary solvent is mixed with a part of the extract liquid at the bottom of Extraction Tower II and then enters Extraction Tower I from the lower part of Extraction Tower I. The remaining extract liquid of Extraction Tower II is mixed with the extract liquid of Extraction Tower I, and after recovering the main solvent, a secondary extract oil is obtained; the raffinate liquid at the top of Extraction Tower I is the feedstock of Extraction Tower II and enters Extraction Tower II from the lower part. The main solvent enters Extraction Tower II from the upper part. The raffinate liquid obtained at the top of Extraction Tower II is used as the feedstock of Extraction Tower III and enters Extraction Tower III from the lower part. The main solvent enters Extraction Tower III from the upper part. The raffinate liquid obtained at the top of Extraction Tower III can be recycled as the secondary solvent. The extract liquid obtained at the bottom of Extraction Tower III is refined by recovering the main solvent to obtain the solvent-refined oil of the anti-gassing component of transformer oil; Step 2: The solvent-refined oil of the anti-gassing component, after liquid-phase denitrification and clay refining, the obtained base oil is the anti-gassing component of transformer oil.

2. The method for producing the anti-gassing components of transformer oil according to claim 1, characterized in that: The main solvent is furfural; the co-solvent is a base oil with a closed-cup flash point of not less than 135 °C, a kinematic viscosity at 40 °C of not more than 12.0 mm 2 / s, a pour point of not higher than -40 °C, and a C A value of not more than 5%.

3. The method for producing the anti-gassing component of transformer oil according to claim 1, characterized in that: The extract oil of the hydrodeacidified oil of transformer oil fraction is the furfural refining extract oil of the naphthenic base hydrodeacidified oil at 280°C - 330°C.

4. The method for producing the anti-gassing component of transformer oil according to claim 1, characterized in that: In Step 1, the top temperature of Extraction Tower I is 50°C - 60°C, the bottom temperature is 40°C, and the mass ratio of the main solvent entering Extraction Tower I to the feedstock is 0.4 - 1.0:

1. The mass ratio of the secondary solvent entering Extraction Tower I to the feedstock is 0.2 - 1.0:

1.

5. The method for producing the anti-gassing component of transformer oil according to claim 1, characterized in that: In Step 1, the top temperature of Extraction Tower II is 60°C - 80°C, the bottom temperature is 40°C - 50°C, and the mass ratio of the main solvent entering Extraction Tower II to the feedstock is 2.5 - 5.0:

1.

6. The method for producing the anti-gassing component of transformer oil according to claim 1, characterized in that: In Step 1, the top temperature of Extraction Tower III is 80°C - 85°C, the bottom temperature is 50°C - 55°C, and the mass ratio of the main solvent entering Extraction Tower III to the feedstock is 2.0 - 5.0:

1.

7. The method for producing the anti-gassing components of transformer oil according to claim 1, characterized in that: In Step 2, the denitrification agent used in the liquid-phase denitrification is WQ-2 or WQ-3. The addition amount of the denitrification agent is 0.3m% - 0.8m% of the solvent-refined oil of the anti-gassing component. The operating conditions are a reaction temperature of 50 - 85°C and a reaction time of 30 - 40 minutes.

8. The method for producing the anti-gassing component of transformer oil according to claim 7, characterized in that: The denitrification agent is WQ-2.

9. The method for producing the anti-gassing components of transformer oil according to claim 1, wherein: In Step 2, the addition amount of clay in the clay refining is 1m% - 8m% of the solvent-refined oil of the anti-gassing component. The refining temperature is 100 - 130°C, and the refining time is 30 - 50 minutes.

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