Method and device for reducing content of dissolved gas in transformer oil

Abstract

The invention provides a method and a device for reducing the content of dissolved gas in transformer oil. The method comprises the following steps: introducing inert gas into transformer base oil to replace soluble gas in the oil so as to reduce the gas content in the oil; the pulse stirring assembly of the device can ensure that inert gas is in full contact with oil, and meanwhile, various components in the transformer base oil are uniformly distributed; the gas content of the product oil obtained by the method and the device is obviously reduced, the hydrogen can be removed by 100%, and the reduction rate of low-molecular hydrocarbons (CH4, C2H6, C2H4 and C2H2) reaches more than 50%.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical industry, and in particular relates to a method and a device for reducing the dissolved gas content in transformer oil. Background Art

[0002] Analysis of dissolved gas content in transformer oil is an important test item for important electrical equipment and is currently the most important technical means for diagnosing internal faults in transformers. Dissolved gas analysis in oil is not affected by external electric fields, magnetic fields and other factors, and provides important technical support for online prediction and diagnosis of early transformer faults. The ultimate goal of analysis of dissolved gas content in transformer oil is to evaluate the operating status of the equipment, determine whether the equipment has latent faults and the causes of the faults, and formulate reasonable maintenance measures to ensure the safe and stable operation of power transmission and transformation equipment and power grids.

[0003] When transformer oil experiences a discharge fault or overheating fault, some CH bonds and CC bonds break, forming H2 and low molecular hydrocarbon gases, including CH4, C2H6, C2H4, C2H2, etc. It may also generate solid carbon particles and hydrocarbon polymers. The oil itself will also generate a small amount of CO and CO2, etc. when it is oxidized. GB / T 7252-2001 "Guidelines for Analysis and Judgment of Dissolved Gases in Transformer Oil" has requirements for the gas content of equipment before leaving the factory and being put into operation. Therefore, transformer manufacturers also have requirements for the dissolved gas in transformer oil entering the factory when purchasing oil products. Some transformer equipment manufacturers require that the transformer oil arriving at the factory must not contain H2 and C2H2, and there are some special index requirements for CH4, C2H6, and C2H4.

[0004] In order to ensure that the transformer oil meets the customer's special requirements for dissolved gas content before leaving the factory, the original technology is to use a vacuum oil filter to degasify the oil during the production process. The disadvantage is that the energy consumption is high and a single treatment cannot guarantee that the index requirements are met.

[0005] Therefore, in order to improve production efficiency and ensure product quality, a new transformer oil blending process was developed. Summary of the invention

[0006] In order to solve the above problems in the prior art, the present invention provides a method and device for reducing the dissolved gas content in transformer oil.

[0007] In a first aspect, the present invention provides a method for reducing the dissolved gas content in transformer oil. The method comprises introducing an inert gas into the transformer base oil to displace the dissolved gas in the oil, thereby reducing the gas content in the oil.

[0008] As a specific embodiment of the present invention, the method further comprises introducing inert gas into the transformer oil under pulse stirring conditions, wherein the amount of the inert gas introduced is 12%-24% of the volume of the transformer base oil.

[0009] As a specific embodiment of the present invention, the inert gas includes nitrogen and argon, preferably nitrogen.

[0010] As a specific implementation of the present invention, the pulse frequency is 4-10 times / minute, the injection time is 5-9 seconds / time, and the interval time is 1-5 seconds / time; the side line stirring rate is 200-400r / min.

[0011] As a specific embodiment of the present invention, the dissolved gas includes CH4, C2H6, C2H4, C2H2, H2, CO and CO2.

[0012] The above raw materials in the present invention can be prepared in-house or commercially available, and the present invention is not particularly limited thereto.

[0013] In a second aspect, the present invention provides a device for reducing the dissolved gas content of transformer oil, the device is an oil tank, and the oil tank comprises:

[0014] A pulse assembly, including a pulse stirring gas collecting disk and a pulse electronic regulating valve;

[0015] a stirring assembly, including a side line stirrer;

[0016] Inert gas introduction component, to introduce dry inert gas into the oil tank;

[0017] Top breathing valve assembly, including drying device and oil-gas separator.

[0018] As a specific embodiment of the present invention, the pulse stirring gas collecting disk is connected to the inert gas pipeline, wherein each inert gas pipeline is connected to 2-6 gas collecting disks, preferably 4, through an electronic regulating valve; the inert gas flow rate is 0.2-0.5m 3 / min. The air collecting plate blows air down from above, and the air is dispersed under the oil, forming bubbles with holes, and then the bubbles will form a pulse stirring of the oil from the bottom to the top due to the pressure.

[0019] As a specific embodiment of the present invention, the pulse stirring gas collecting plate is 1-2 cm away from the bottom of the tank.

[0020] As a specific embodiment of the present invention, 1-4 groups of pulse stirring gas collecting disks are arranged in the oil tank. The number of pulse stirring gas collecting disks is adaptively adjusted according to the size of the oil tank so that the inert gas is evenly dispersed from the bottom, thereby forming uniform pulse stirring.

[0021] As a specific implementation of the present invention, the pulse regulating valve is located at the top of the tank and is used to regulate the inert gas entering the gas collecting disk.

[0022] As a specific embodiment of the present invention, the side line agitator is located at the upper 1 / 2 to 1 / 3 of the oil tank, with a stirring rate of 200-400r / min and a stirring blade size of 10-20cm. The side line agitator is to allow the low molecular hydrocarbons in the upper part to overflow more easily. In addition, the side line agitator can also provide stirring power for the preparation of transformer base oil. Specifically, various components in the base oil are mixed and added to the oil tank, heated to 50-70°C, and stirred and dissolved using a side line agitator for 0.5h-2h.

[0023] As a specific embodiment of the present invention, the drying device is located at the outlet of the top breathing valve; the drying device includes a desiccant; the desiccant includes silica gel, water-absorbing resin and activated carbon; the oil-gas separator is used to separate the oil that may volatilize. Among them, the desiccant should be replaced regularly according to the humidity to prevent water vapor in the air from entering the oil tank, and the activated carbon is used to adsorb low molecular hydrocarbons. The activated carbon needs to be replaced every 6 months to ensure its adsorption capacity.

[0024] As a specific embodiment of the present invention, the working process of the device for reducing the dissolved gas content in transformer oil includes:

[0025] S1: After the transformer base oil is pumped into the oil tank, dry nitrogen is introduced for pulse stirring for 2-4 hours;

[0026] S2: Nitrogen replaces the gas dissolved in the oil. In the last 10-30 minutes of pulse stirring, open the breathing valve and allow the replaced gas to overflow through the breathing valve through side-line stirring.

[0027] S3: Stop pulse stirring and side-line stirring, and close the breathing valve.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention introduces inert gas into transformer base oil to replace low molecular hydrocarbons in the oil, thereby reducing the gas content in the oil.

[0030] 2. The present invention can ensure that the inert gas is in full contact with the oil through pulse stirring, and at the same time, various components in the transformer base oil are evenly distributed.

[0031] 3. Compared with the prior art, the gas content of the finished oil obtained by the method and device of the present invention is significantly reduced, hydrogen can be removed 100%, and the reduction rate of low molecular hydrocarbons (CH4, C2H6, C2H4, C2H2) is more than 50%. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of a device for reducing the dissolved gas content in transformer oil provided in Example 1 of the present invention;

[0033] Among them, 1-pulse stirring gas collecting disk, 2-finished oil outlet, 3-pulse regulating valve; 4-dry nitrogen pipeline; 5-side line agitator; 6-base oil inlet; 7-oil tank; 8-breathing valve assembly. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with specific embodiments, but they do not constitute any limitation to the present invention.

[0035] Example 1

[0036] This embodiment provides a device for reducing the dissolved gas content in transformer oil, and the specific details are as follows:

[0037] The device is an oil tank 7, the inert gas is nitrogen, and the oil tank includes:

[0038] The pulse assembly is a pulse stirring gas collecting disk 1 and a pulse regulating valve 3; the pulse stirring gas collecting disk 1 is connected to the nitrogen pipeline 4, wherein each nitrogen pipeline line is connected to four gas collecting disks through a regulating valve; the pulse stirring gas collecting disk is 2 cm away from the bottom of the tank; four groups of pulse stirring gas collecting disks are arranged in the oil tank and are evenly distributed; the pulse regulating valve is located at the top of the tank to regulate the nitrogen entering the gas collecting disk.

[0039] The stirring component is a side line stirrer 5; the side line stirrer 5 is located at the upper 1 / 3 of the oil tank 7, and is controlled by a motor. The stirring rate can be adjusted in the range of 200-400r / min, and the diameter of the stirring blade is approximately 20cm;

[0040] Nitrogen inlet assembly, pass dry nitrogen into the oil tank through the pipeline; the inert gas flow rate is 0.2-0.5m 3 / min;

[0041] The breathing valve assembly 8 includes a drying device and an oil-gas separator. The breathing valve assembly is located at the top of the oil tank. There is a desiccant in the drying device at the outlet of the breathing valve. The desiccant can be selected from silica gel or water-absorbing resin and activated carbon according to actual conditions. Silica gel or water-absorbing resin can prevent water vapor in the air from entering the oil tank and should be replaced regularly according to humidity conditions. Activated carbon is used to adsorb low molecular weight hydrocarbons. The activated carbon is replaced every 3-6 months according to actual conditions to ensure its adsorption capacity. The oil-gas separator is used to separate oil that may evaporate.

[0042] A base oil inlet 6 is provided at the top of the oil tank, and a finished oil outlet 2 is provided at the bottom.

[0043] Example 2

[0044] This embodiment provides a method for reducing the dissolved gas content in transformer oil, which is implemented by the device provided in Example 1. The specific details are as follows:

[0045] The dissolved gas content in the transformer base oil used in this embodiment is: CH4 is 1.65μL / L; C2H6 is 3.57μL / L; C2H4 is 0.19μL / L; C2H2 is 0μL / L; H2 is 8.19μL / L; CO is 0μL / L; CO2 is 386.8μL / L.

[0046] After the mineral transformer oil base oil is introduced into the oil tank, the nitrogen pipeline is opened and the nitrogen flow rate is 0.4m 3 / min, nitrogen pulse stirring for 3h, pulse parameters are: pulse frequency 8 times / min, injection time 5 seconds / time, interval time 3 seconds / time; open the breathing valve, open the side line agitator, stirring rate 300r / min, side line stirring 40min. Stop pulse stirring and side line stirring, close the breathing valve, and obtain finished oil. After standing for 1h, sample and analyze the dissolved gas content in the finished oil: CH4 is 0.77μL / L; C2H6 is 0.02μL / L; C2H4 is 0.02μL / L; C2H2 is 0μL / L; H2 is 0μL / L; CO is 0μL / L; CO2 is 301.5μL / L.

[0047] The H2 removal rate in the transformer base oil in Example 2 is 100%, and the reduction rate of low molecular hydrocarbons (CH4, C2H6, C2H4, C2H2) is 85%.

[0048] Example 3

[0049] This embodiment provides a method for reducing the dissolved gas content in transformer oil, which is implemented by the device provided in Example 1. The specific details are as follows:

[0050] The dissolved gas contents in the transformer base oil used in this embodiment are: CH4 is 1.24 μL / L; C2H6 is 3.33 μL / L; C2H4 is 0.20 μL / L; C2H2 is 0 μL / L; H2 is 0 μL / L; CO is 0 μL / L; CO2 is 424.4 μL / L.

[0051] Add mineral transformer oil base oil into the oil tank and open the nitrogen pipeline with a nitrogen flow rate of 0.3m 3 / min, nitrogen pulse stirring for 2h, pulse parameters are: pulse frequency 5 times / min, injection time 6 seconds / time, interval time 2 seconds / time; open the breathing valve, open the side line agitator, the stirring rate is 300r / min, and the side line is stirred for 30min. Stop pulse stirring and side line stirring, close the breathing valve, and obtain the finished oil. After standing for 1h, sample and analyze the dissolved gas content in the oil: CH4 is 0.74μL / L; C2H6 is 0.05μL / L; C2H4 is 0.02μL / L; C2H2 is 0μL / L; H2 is 0μL / L; CO is 0μL / L; CO2 is 298.4μL / L.

[0052] The reduction rate of low molecular weight hydrocarbons (CH4, C2H6, C2H4, C2H2) in the transformer base oil in Example 3 is 83%.

[0053] Example 4

[0054] This embodiment provides a method for reducing the dissolved gas content in transformer oil, which is implemented by the device provided in Example 1. The specific details are as follows:

[0055] The dissolved gas contents in the transformer base oil used in this embodiment are: CH4 is 1.24 μL / L; C2H6 is 0.84 μL / L; C2H4 is 0.22 μL / L; C2H2 is 0 μL / L; H2 is 0.5 μL / L; CO is 0 μL / L; CO2 is 398.7 μL / L.

[0056] After the mineral transformer oil base oil is introduced into the oil tank, the nitrogen pipeline is opened and the nitrogen flow rate is 0.25m 3 / min, nitrogen pulse stirring for 3h, pulse parameters are: pulse frequency 8 times / min, injection time 5 seconds / time, interval time 3 seconds / time; open the breathing valve, turn on the side line agitator, the stirring rate is 400r / min, and the side line stirring is 10min. Stop pulse stirring and side line stirring, close the breathing valve. After standing for 1h, sample and analyze the dissolved gas content in the oil: CH4 is 0.73μL / L; C2H6 is 0μL / L; C2H4 is 0μL / L; C2H2 is 0μL / L; H2 is 0μL / L; CO is 0μL / L; CO2 is 311.2μL / L.

[0057] The H2 removal rate in the transformer base oil in Example 4 is 100%, and the reduction rate of low molecular hydrocarbons (CH4, C2H6, C2H4, C2H2) is 68%.

[0058] Comparative Example 1

[0059] This comparative example provides a method for reducing the dissolved gas content in transformer oil. Compared with Example 2, no pulse is added, and the transformer base oil used is the same as that in Example 2; the dissolved gas content in the transformer finished oil obtained in this comparative example is CH4 of 1.24 μL / L; C2H6 of 1.25 μL / L; C2H4 of 0.84 μL / L; C2H2 of 0 μL / L; H2 of 2 μL / L; CO of 0 μL / L; and CO2 of 402.5 μL / L.

[0060] By comparing Comparative Example 1 with Example 2, it can be seen that if pulses are not added in the method of reducing the dissolved gas content in transformer oil of the present application, the effect will be worse.

[0061] In summary, the present invention reduces the gas content in the transformer base oil by introducing inert gas to displace low molecular hydrocarbons in the oil. By adding pulses, it is further ensured that nitrogen is in full contact with the oil. Compared with the prior art, the gas content of the finished oil obtained by the method and device of the present invention is significantly reduced through the embodiments, hydrogen can be removed by 100%, and the reduction rate of low molecular hydrocarbons (CH4, C2H6, C2H4, C2H2) is more than 50%.

[0062] Any numerical value mentioned in the present invention, if there is only an interval of two units between any minimum value and any maximum value, includes all values ​​from the minimum value to the maximum value each time increasing by one unit. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, time, etc. is declared to be 50-90, in this specification it means that 51-89, 52-88... and 69-71 and 70-71 are specifically listed. For non-integer values, 0.1, 0.01, 0.001 or 0.0001 can be appropriately considered as a unit. These are just some specially specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0063] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A method for reducing the dissolved gas content of transformer oil, characterized in that: The method comprises the steps of introducing inert gas into transformer base oil to displace dissolved gas therein and reduce the gas content therein.

2. The method according to claim 1, characterized in that: The method also includes introducing inert gas into the transformer oil under the condition of pulse stirring, wherein the amount of the inert gas introduced is 12%-24% of the volume of the transformer base oil.

3. The method according to claim 1 or 2, characterized in that: The inert gas includes nitrogen, argon, helium, preferably nitrogen.

4. The method according to any one of claims 1 to 3, characterized in that: The pulse frequency is 4-10 times / minute, the injection time is 5-9 seconds / time, and the interval time is 1-5 seconds / time; the side line stirring rate is 200-400r / min.

5. The method according to any one of claims 1 to 4, characterized in that: The dissolved gases include CH4, C2H6, C2H4, C2H2, H2, CO and CO2.

6. A device for reducing the dissolved gas content in transformer oil for implementing the method according to any one of claims 1 to 5, characterized in that: The device is an oil tank, which includes: A pulse assembly, including a pulse stirring gas collecting disk and a pulse regulating valve; a stirring assembly, including a side line stirrer; Inert gas is introduced into the assembly, and dry inert gas is introduced into the oil tank through the pipeline; Breathing valve assembly, including drying device and oil-gas separator.

7. The device according to claim 6, characterized in that The pulse stirring gas collecting disk is connected to the inert gas pipeline, wherein each inert gas pipeline is connected to 2-6 gas collecting disks, preferably 4, through an electronic regulating valve. The inert gas flow rate is 0.2-0.5m 3 / min. The distance between the pulse stirring gas collecting disk and the tank bottom is 1-2 cm; 1-4 groups of pulse stirring gas collecting disks are arranged in the oil tank; The pulse regulating valve is located at the top of the tank and is used to regulate the inert gas entering the gas collecting disk.

8. The device according to claim 6, characterized in that The side line agitator is located at the upper 1 / 2 to 1 / 3 of the oil tank, with a stirring rate of 200-400r / min and a stirring blade size of 10-20cm.

9. The device according to claim 6, characterized in that The breathing valve assembly is located at the top of the oil tank; wherein the drying device is located at the outlet of the breathing valve assembly; the drying device includes a desiccant; the desiccant includes silica gel, water-absorbing resin and activated carbon; the oil-gas separator is used to separate the volatile oil.

10. The device according to any one of claims 6 to 9, characterized in that: The workflow includes: S1: After the transformer base oil is pumped into the oil tank, dry inert gas is introduced for pulse stirring for 2-4 hours; S2: The inert gas displaces the gas dissolved in the oil. In the last 10-30 minutes of pulse stirring, open the breathing valve and allow the displaced gas to overflow through the breathing valve through side-line stirring. S3: Stop pulse stirring and side-line stirring, and close the breathing valve.

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