Fully automated SF6 purification and refining device and method for detecting impurity gases

Abstract

This invention discloses a fully automated SF6 purification and refining device for detecting impurity gases, comprising a control module and an air intake assembly. The air intake assembly is divided into two paths: a first purification path sequentially connects to a gas storage tank, a first gas detection module, a first buffer tank, a first purification unit, a second gas detection module, a second buffer tank, and a back-end processing unit via pipelines; the second buffer tank is also connected to the first buffer tank via pipelines; the second purification path sequentially connects to a third gas detection module, a third buffer tank, and the second purification unit via pipelines; both the air intake and exhaust ends of the second purification unit are connected to the front end of the first purification unit; the first purification unit includes an alkaline solution treatment module, an adsorption module, and a first refrigeration module that can be connected in parallel and in series. This invention also discloses a method. The beneficial effects of this invention are: different purification paths are selected for different impurity gases, the purification methods are comprehensive, effective purification is achieved, and purification and refining efficiency and work efficiency are improved.

Description

Technical Field

[0001] This invention relates to an SF6 purification technology, and more particularly to an SF6 purification and refining apparatus and method. Background Technology

[0002] GB / T 12022-2014, "Industrial Sulfur Hexafluoride," clearly defines gaseous impurities. Currently, in on-site SF6 purification and refining operations, the equipment is relatively limited in function, selectively filtering only a few types of gaseous impurities. For SF6 recovery gases from different sources, it is often necessary to first use a gaseous impurity detection device to determine the types and amounts of impurities, and then select the appropriate purification method and equipment based on the detection results. This involves significant manual intervention and low work efficiency. If the purified SF6 recovery gas contains many types of gaseous impurities, multiple detections and purifications are required, further increasing the complexity, time-consuming, and labor-intensive process, and resulting in lower quality SF6 gas after purification. Therefore, it is necessary to design a fully automated SF6 purification and refining method and device based on fully automated impurity gas detection, incorporating multiple purification modules that can automatically select different purification processes based on gaseous impurity detection results, efficiently and quickly refining high-quality SF6 gas.

[0003] Publication No. CN111186819A discloses a sulfur hexafluoride gas purification system, which mainly includes an alkaline washing unit and a drying unit, and can effectively remove acidic components and moisture from sulfur hexafluoride gas. Specific implementation method: The sulfur hexafluoride gas to be purified enters the device from the inlet 01, and first passes through the pretreatment unit 10 (including the dust filter 11 and the inlet pressure sensor 12) to filter out solid particles and monitor the gas pressure in real time; then the gas is depressurized through the inlet pressure reducing valve 04, and after depressurization, the comprehensive detector 03 detects whether the trace moisture and decomposition products meet the standards. According to the detection results, there are four situations, and different purification paths are selected by controlling the control valves at each key position: (1) Only the acidity is too high; open the control valve 41, pass through the first four alkaline absorption towers (black tanks) from left to right, then through the two desiccant adsorption towers, and finally discharge the purified sulfur hexafluoride gas through the outlet 02. (2) Only the moisture content is too high; control valve 41 is closed, and the gas is directly transmitted to the two desiccant adsorption towers through the path of pipeline 60. Control valve 42 is closed at this time, and finally the purified sulfur hexafluoride gas is discharged through outlet 02. (3) Both acidity and moisture are too high; control valve 41 is opened, and the gas is transmitted through the first four alkaline absorption towers (black tanks) from left to right, then through the two desiccant adsorption towers, and finally through outlet 02. (4) Both acidity and moisture are normal; the purified sulfur hexafluoride gas is discharged directly from outlet 02 through the gas branch of pipeline 70. (5) Regeneration of the desiccant adsorption medium in the desiccant adsorption tower; when the desiccant adsorption tower adsorbs for a long time, the water absorption capacity of the desiccant medium decreases, and the desiccant medium needs to be regenerated. The absorbed water is turned into gas by the heating device installed in the desiccant adsorption tower; control valves 43 and 91 are opened, nitrogen is injected into the desiccant adsorption tower, and the water is discharged from outlet 90 by the vacuum pump. (6) Alkali replacement in alkaline adsorption tower: A pH meter is installed on the alkaline adsorption tower. The pH value is observed to determine whether the alkaline solution needs to be replaced.

[0004] This patent can only adsorb trace amounts of water and acidic gases, but it cannot effectively remove a large number of neutral gases, such as N2, CF4, C2F6, and C3F8, which are present in the gaseous impurities.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The technical problem to be solved by this invention is: how to solve the problem that the purification and refining process of SF6 in the prior art often requires multiple purification devices, multiple tests, and multiple removals of various impurity gases, which is cumbersome and inefficient.

[0007] The present invention solves the above-mentioned technical problems through the following technical means:

[0008] The fully automatic SF6 purification and refining device with impurity gas detection includes a control module, and an intake assembly, a gas storage tank, a first gas detection module, a first buffer tank, a first purification unit, a second gas detection module, a second buffer tank, a back-end processing unit, a third gas detection module, a third buffer tank, and a second purification unit electrically connected to the control module.

[0009] The air intake assembly is divided into two paths: a first purification path and a second purification path. The first purification path is connected in sequence via pipes to a gas storage tank, a first gas detection module, a first buffer tank, a first purification unit, a second gas detection module, a second buffer tank, and a back-end processing unit. The second buffer tank is also connected to the first buffer tank via pipes. The second purification path is connected in sequence via pipes to a third gas detection module, a third buffer tank, and a second purification unit. The air intake and exhaust ends of the second purification unit are also connected to the pipes between the first buffer tank and the first purification unit.

[0010] The first purification unit includes an alkaline solution treatment module, an adsorption module, and a first refrigeration module that can be connected in parallel and in series.

[0011] This invention sets up two purification routes based on the material states of sulfur hexafluoride (SF6), treating impurities in predominantly liquid and predominantly gaseous SF6 respectively. Furthermore, by setting up a first purification unit and a second purification unit to process different impurity gases, this invention can automatically select different purification paths based on gas detection results. The comprehensive purification methods effectively purify the main gaseous impurities in SF6, improving purification efficiency and ensuring that the purified SF6 meets virgin gas standards. This invention also features a control module with preset detection concentration and weight values, with the entire process controlled by the control module for path selection, minimizing manual intervention and improving work efficiency.

[0012] Preferably, the air intake assembly includes a gas cylinder, a first weighing device, and a first pressure reducing valve. The gas cylinder is connected upside down to the first weighing device, and the first pressure reducing valve is connected to the gas cylinder. The outlet of the first pressure reducing valve is divided into two paths.

[0013] Preferably, the system further includes a first vaporizer, a second pressure reducing valve, and a first compressor. The first vaporizer is connected to the inlet of the gas storage tank, and the outlet of the gas storage tank is connected to the second pressure reducing valve. The first gas detection device is connected in parallel to the gas pipeline at the outlet of the second pressure reducing valve. The first compressor is connected to the outlet of the first buffer tank, and the outlet of the first compressor is connected to the alkali treatment module and the adsorption module.

[0014] Preferably, the adsorption module includes at least three adsorption towers connected in series, at least one of which is a desiccant adsorption tower, at least one of which is a molecular sieve adsorption tower, and at least one of which is an activated carbon adsorption tower.

[0015] Multiple adsorption towers can be used to remove gaseous impurities such as water, SO2, and C3F8, enabling comprehensive removal of impurity gases.

[0016] Preferably, it further includes a third pressure reducing valve and a second compressor. The third pressure reducing valve is connected to the outlet of the first purification unit, the second gas detection module is connected in parallel to the outlet pipe of the third pressure reducing valve, the second buffer tank is connected to the outlet of the second gas detection module, and the second compressor is connected to the outlet of the second buffer tank.

[0017] Preferably, the back-end processing unit includes a second refrigeration module and a filling unit. The second refrigeration module is connected to the outlet of the second compressor, the filling unit is connected to the second refrigeration module, and the second refrigeration module is also connected to a gas storage tank via a pipeline.

[0018] Preferably, it further includes a second vaporizer, which is connected to the outlet end of the first refrigeration module and located at the inlet end of the third gas detection module.

[0019] Preferably, the second purification unit is a polymer membrane, and the outlet end of the second purification unit is also connected to a vacuum component.

[0020] This invention selects different purification paths based on the weight of the gas cylinder, and separates the high-concentration nitrogen gas enriched in the residual gas through a polymer membrane, thereby improving the nitrogen purification capacity.

[0021] The device can be evacuated before the first operation to avoid interference from impurity gases.

[0022] This invention also discloses a method for a fully automated SF6 purification and refining device for detecting impurity gases, comprising the following steps:

[0023] Step 1: When the weight of the gas cylinder to be purified is greater than the preset weight M of the control module, the first purification route is entered, and the liquid sulfur hexafluoride enters the storage tank after depressurization and vaporization.

[0024] Step 2: After the gas in the storage tank is depressurized again, it enters the first buffer tank. Some of the gas in the storage tank also enters the first gas detection module to detect the content of impurity gases.

[0025] Step 3: Based on the impurity gas detection results detected by the first gas detection module, selectively enter one or more of the alkaline solution treatment module, adsorption module, and first refrigeration module;

[0026] Step 4: When the weight of the gas cylinder to be purified is less than the preset weight M of the control module, it enters the second purification route. After depressurization, the gas enters the third buffer tank. After depressurization, part of the gas also enters the third gas detection module to detect the content of impurity gas. According to the impurity gas detection results of the third gas detection module, it selectively enters the second purification unit or directly enters the outlet of the first buffer tank and then selectively enters one or more of the alkaline treatment module, adsorption module, and first refrigeration module.

[0027] Step 5: The purified gas is tested again by the second gas detection module. If the gas passes the test, it is liquefied and bottled by the back-end processing unit. If the gas fails the test, it is returned to the storage tank for continued purification.

[0028] Preferably, in step three, if only the SO2 concentration exceeds the preset value, the gas passes through the alkaline solution treatment module and the adsorption module sequentially; if only the CF4 concentration exceeds the preset value, the gas directly enters the adsorption module and then the first refrigeration module; if both the SO2 and CF4 or C2F6 concentrations exceed the preset values, the gas passes through the alkaline solution treatment module, the adsorption module, and the first refrigeration module sequentially; if the SO2, CF4, and C2F6 concentrations all meet the requirements, the gas only passes through the adsorption module.

[0029] In step four, if the nitrogen concentration exceeds a preset value, the gas enters the second purification unit and then the outlet of the first buffer tank. Based on the detection results of SO2, CF4, and C2F6 concentrations detected by the third gas detection module, it selectively enters one or more of the alkali treatment module, adsorption module, and first refrigeration module. If the nitrogen concentration is qualified, the gas directly enters the outlet of the first buffer tank. Based on the detection results of SO2, CF4, and C2F6 concentrations detected by the third gas detection module, it selectively enters one or more of the alkali treatment module, adsorption module, and first refrigeration module.

[0030] The advantages of this invention are:

[0031] (1) Based on the material state of sulfur hexafluoride, this invention sets up two purification routes to treat the impurities of sulfur hexafluoride that is mainly in liquid and gaseous states, respectively. Furthermore, by setting up a first purification unit and a second purification unit, this invention can treat different impurity gases and can automatically select different purification paths based on the gas detection results. The purification methods are comprehensive and can effectively purify the main gaseous impurities in sulfur hexafluoride gas, improve the purification efficiency, and make the purified SF6 meet the new gas standards. This invention presets multiple detection concentration values, weight values, etc. in the control module, and the path selection is controlled by the control module throughout the process, with less manual intervention, which improves work efficiency.

[0032] (2) Multiple adsorption towers can be used to remove gaseous impurities such as water, SO2, and C3F8, and can comprehensively remove impurity gases.

[0033] (3) Sulfur hexafluoride is separated from CF4 and C2F6 by the refrigeration module. If a small amount of sulfur hexafluoride is mixed in the gas phase of the refrigeration module, the gas is introduced into the first buffer tank for continued circulation and purification to avoid waste.

[0034] (4) The present invention selects different purification paths according to the weight of the cylinder and separates the high concentration of nitrogen in the residual gas through a polymer membrane, thereby improving the nitrogen purification capacity.

[0035] (5) The device can be evacuated before the first operation to avoid interference from impurity gases;

[0036] (6) It can complete all the work tasks of sulfur hexafluoride gas purification without the need for other testing instruments or purification equipment, thus improving the workload. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the SF6 purification and refining device for fully automated impurity gas detection according to an embodiment of the present invention;

[0038] Figure 2 yes Figure 1 Schematic diagram of the structure of the first purification unit;

[0039] Numbering on the map:

[0040] 1. Intake assembly; 11. Sulfur hexafluoride cylinder; 12. First weighing device; 13. First pressure reducing valve;

[0041] 2. First detection unit; 21. First vaporizer; 22. Gas storage tank; 23. Second pressure reducing valve; 24. First gas detection module; 25. First buffer tank; 26. First compressor;

[0042] 3. First purification unit; 31. Alkali treatment module; 311. pH meter; 32. Adsorption module; 321. Desiccant adsorption tower; 322. Molecular sieve adsorption tower; 323. Activated carbon adsorption tower; 33. First refrigeration module; 331. First refrigerator; 332. First level gauge; 333. First refrigeration tank; 34. Second vaporizer;

[0043] 4. Second detection unit; 41. Third pressure reducing valve; 42. Second gas detection module; 43. Second buffer tank; 44. Second compressor;

[0044] 5. Back-end processing unit; 51. Second refrigeration module; 52. Canning unit; 521. Liquid pump; 522. Cylinder to be filled; 523. Second weighing device;

[0045] 6. Third detection unit; 61. Third compressor; 62. Fourth pressure reducing valve; 63. Third gas detection module; 64. Third buffer tank;

[0046] 7. Second purification unit; 71. Polymer membrane; 72. Fourth compressor;

[0047] 8. Vacuum components; 81. Vacuum pump; 82. Vacuum gauge; Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Example 1:

[0050] like Figure 1 As shown, the fully automatic SF6 purification and refining device for detecting impurity gases includes an intake assembly 1 comprising a sulfur hexafluoride cylinder 11, a first weighing device 12, and a first pressure reducing valve 13; and a first detection unit 2 comprising a first vaporizer 21, a gas storage tank 22, a second pressure reducing valve 23, a first gas detection module 24, a first buffer tank 25, and a first compressor 26.

[0051] The first purification unit 3 includes an alkaline solution treatment module 31, an adsorption module 32, and a first refrigeration module 33; the second detection unit 4 includes a third pressure reducing valve 41, a second gas detection module 42, a second buffer tank 43, and a second compressor 44; the back-end processing unit 5 includes a second refrigeration module 51 and a canning unit 52; the third detection unit 6 includes a third compressor 61, a fourth pressure reducing valve 62, a third gas detection module 63, and a third buffer tank 64; the second purification unit 7 includes a polymer membrane 71 and a fourth compressor 72; in this embodiment, the control module (not shown in the figure) is electrically connected to the above-mentioned parts. The control module is mainly responsible for setting preset values ​​and controlling the opening and closing of the solenoid valve according to the detection results, which can be achieved by using a controller in the prior art.

[0052] It is known that GB / T 12022-2014 "Industrial Sulfur Hexafluoride" has made clear provisions for gaseous impurities, and the data is shown in the table below.

[0053] <![CDATA[Purity (mass fraction) of sulfur hexafluoride (SF6) / 10 -2 > ≥99.9％ <![CDATA[Air (mass fraction) / 10 -6 > ≤300 <![CDATA[Carbon tetrafluoride (CF4) (mass fraction) / 10 -6 > ≤100 <![CDATA[Hexafluoroethane (C2F6) (mass fraction) / 10 -6 > ≤200 <![CDATA[Octafluoropropane (C3F8) (mass fraction) / 10 -6 > ≤50 <![CDATA[Water (mass fraction) / 10 -6 > ≤5 <![CDATA[Acidity (calculated as hydrofluoric acid (HF)) (mass fraction) / 10 -6 > ≤0.2 <![CDATA[Hydrolyzable fluoride (calculated as hydrofluoric acid (HF)) (mass fraction) / 10 -6 > ≤1

[0054] Therefore, this embodiment aims to comprehensively purify sulfur hexafluoride gas so that all its parameters meet the specified standards.

[0055] In this embodiment, the gas is divided into two paths after the intake component 1 is depressurized. The two paths are the first purification path and the second purification path, which will be described separately below.

[0056] The first purification route connects the first detection unit 2, the first purification unit 3, the second detection unit 4, and the back-end processing unit 5 sequentially via pipelines; the second purification route connects the third detection unit 6 and the second purification unit 7 sequentially via pipelines. The polymer membrane 71 can also be connected to the outlet of the first compressor 26 via the fourth compressor 72. The alkaline solution treatment module 31, the adsorption module 32, and the first refrigeration module 33 in the first purification unit 3 can be connected in parallel and in series.

[0057] Explanation of the first purification route:

[0058] The first pressure reducing valve 13 is connected to the sulfur hexafluoride (SF6) cylinder 11, and a pressure gauge is connected to the rear end of the SF6 cylinder 11 to detect the outlet pressure. Since the SF6 in the cylinder to be purified is in a gas-liquid coexistence state, and the gaseous impurities are mainly present in the gas phase, in this embodiment, the SF6 cylinder 11 is placed upside down on the first weighing device 12 using a support. The weight of the SF6 cylinder 11 on the first weighing device 12 is set to a kg (generally 45-55 kg, or preset based on experience). The valve of the SF6 cylinder 11 is opened. When the cylinder weight is greater than a, the solenoid valve V1 is opened and the solenoid valve V11 is closed, allowing liquid SF6 to enter the first purification route.

[0059] It should be noted that different sulfur hexafluoride (SF6) cylinders have varying weights, with an empty cylinder weighing approximately 45 kg. SF6 is bottled in liquid form; generally, non-empty cylinders contain a mixture of liquid and gaseous SF6, with the liquid at the bottom and the gaseous at the top. Therefore, the cylinder weight is preset to 1 kg. Below 1 kg, the cylinder contains less liquid SF6 and primarily gaseous SF6; similarly, above 1 kg, there is more liquid SF6 and less gaseous SF6. Nitrogen has poor solubility in liquid SF6, so it mainly exists in the gas phase and is only treated when the weight is below 1 kg. Other gaseous impurities have good solubility in liquid SF6 and mainly exist in the liquid SF6, thus requiring two separate purification paths.

[0060] The first vaporizer 21 is connected to the inlet of the gas storage tank 22, and the outlet of the gas storage tank 22 is connected to the second pressure reducing valve 23. The first gas detection module 24 is connected in parallel to the gas pipeline at the outlet of the second pressure reducing valve 23. The first compressor 26 is connected to the outlet of the first buffer tank 25, and the outlet of the first compressor 26 is connected to the first purification unit 3. Pressure gauges are installed on both the gas storage tank 22 and the first buffer tank 25. The first gas detection module 24 is used to measure SO2, CF4, and C2F6.

[0061] refer to Figure 2 As shown, in this embodiment, the first purification unit 3 includes three modules: an alkaline solution treatment module 31, an adsorption module 32, and a first refrigeration module 33.

[0062] The alkaline solution treatment module 31 is an alkaline solution tank containing 1% NaOH solution or 2% KOH solution (or other commonly used alkaline solutions). The alkaline solution tank also includes a pH meter 311 for detecting the pH value. When the pH value reaches 11.0, the alkaline solution needs to be replaced. The inlet and outlet of the alkaline solution tank are connected to solenoid valves V3 and V7, respectively, to control whether the air enters the alkaline solution tank and whether the treated air enters the adsorption module 32.

[0063] In this embodiment, the adsorption module 32 includes three adsorption towers connected in series. The desiccant adsorption tower 321 contains a desiccant, the molecular sieve adsorption tower 322 contains 4A molecular sieve, and the activated carbon adsorption tower 323 contains activated carbon. These towers can be used to remove gaseous impurities such as water, SO2, and C3F8. A solenoid valve V4 is connected to the inlet of the adsorption module 32, and a solenoid valve V9 is connected to the outlet of the adsorption module 32.

[0064] The first refrigeration module 33 includes a first refrigerator 331, a first liquid level gauge 332, and a first refrigeration tank 333. Gas enters the first refrigeration tank 333 and exchanges heat with the coolant pipe of the first refrigerator 331 to achieve cooling and liquefaction. The first liquid level gauge 332 displays the liquid level in the refrigeration tank. The inlet end of the first refrigeration module 33 is connected to a solenoid valve V8, which is connected to the outlet end of the adsorption module 32 and located in front of the solenoid valve V9. The liquid outlet end of the first refrigeration module 33 is also connected to a second vaporizer 34 and a solenoid valve V10, and is connected to the rear end of the solenoid valve V9. The gas phase of the first refrigeration module 33 also contains a small amount of sulfur hexafluoride. The preset liquid level in the first refrigeration tank 333 is hhm. When the liquid level in the tank is lower than h, the solenoid valve V10 is closed and the solenoid valve V6 is opened, allowing the gas to be introduced into the first buffer tank 25 for continued circulation and purification.

[0065] The second detection unit 4 is mainly used to re-detect the purified gas. It can detect the content of water, SO2, CF4 and C2F6. After purification, the gas is depressurized by the third pressure reducing valve 41 and then enters the second buffer tank 43. After vaporization, a small portion of the gas enters the third gas detection module 63. The outlet of the second buffer tank 43 is connected to the second compressor 44. The content of impurity gas can be detected by the third gas detection module 63. If the content exceeds the preset value, it will return to the gas storage tank 22 for circulation purification through the solenoid valve V19.

[0066] The outlet end of the second compressor 44 is connected to a solenoid valve V20. The other end of the solenoid valve V20 is connected to the second refrigeration module 51 for liquefaction. The outlet end of the second refrigeration module 51 is connected to a solenoid valve V21. The solenoid valve V21 is connected to a filling unit 52. The filling unit 52 includes a liquid pump 521, a cylinder to be filled 522, and a second weighing device 523. After liquefaction, the liquid is pumped into the cylinder to be filled 522 by the liquid pump 521, and the filling weight is measured by the second weighing device 523. A pressure gauge is installed on the input pipeline.

[0067] The second refrigeration module 51 has the same structure as the first refrigeration module 33. When a small amount of liquid and a large amount of gas remain in the second refrigeration module 51, the solenoid valve V2 is opened, and the system returns to the first buffer tank 25 to continue circulating, in the same way as the first refrigeration module 33.

[0068] Explanation of the second purification route:

[0069] Solenoid valves V11, V12, and the fourth pressure reducing valve 62 are connected in sequence. Solenoid valve V12 is also connected in parallel to solenoid valve V13 and the third compressor 61. After the fourth pressure reducing valve 62 reduces the pressure, the gas enters the third buffer tank 64. A small amount of gas enters through the branch third gas detection module 63 after the fourth pressure reducing valve 62 for measurement. The outlet of the third buffer tank 64 is connected to the polymer membrane 71 through solenoid valve V15, and is also connected to the outlet of the first compressor 26 through solenoid valves V14, the fourth compressor 72, and solenoid valve V5. The outlet of the polymer membrane 71 is also connected to the inlet of the fourth compressor 72 through solenoid valve V16.

[0070] The third gas detection module 63 can measure nitrogen, SO2, CF4, and C2F6. It judges whether the nitrogen content exceeds a preset value. If the nitrogen content is higher than the preset value, it enters the polymer membrane 71 for purification. After purification, the gas is returned to the rear end of the first compressor 26 by the fourth compressor 72. Based on the SO2, CF4, and C2F6 content obtained by the third gas detection module 63, the first purification unit 3 performs selective processing. If the nitrogen concentration is qualified, it bypasses the polymer membrane 71 and is directly returned to the rear end of the first compressor 26 by the fourth compressor 72. Based on the SO2, CF4, and C2F6 content obtained by the third gas detection module 63, the first purification unit 3 performs selective processing.

[0071] In this embodiment, the first gas detection module 24, the second gas detection module 42, and the third gas detection module 63 can be any existing equipment capable of detecting major impurity gases such as nitrogen, water, SO2, CF4, C2F6, and C3F8.

[0072] In this embodiment, all solenoid valves are controlled by the control module. Under the control of the control module, automatic on / off switching can be achieved, which is conducive to achieving full automation.

[0073] In this embodiment, two purification routes are set up according to the state of impurity gases in sulfur hexafluoride, to treat the liquid-dominated and gas-dominated sulfur hexafluoride respectively; the alkaline tank is used to treat SO2, and multiple adsorption towers can be used to remove gaseous impurities such as water, SO2 and C3F8, which can comprehensively remove impurity gases; the refrigeration module separates sulfur hexafluoride from CF4 and C2F6, and if a small amount of sulfur hexafluoride is mixed in the gas phase of the refrigeration module, the gas is introduced to the back end of the first compressor 26 for continued circulation and purification to avoid waste; different purification paths are selected according to the weight of the cylinder, and the high-concentration nitrogen enriched in the residual gas is separated by the polymer membrane 71, which improves the nitrogen purification capacity. Therefore, this embodiment can process different impurity gases through the first purification unit 3 and the second purification unit 7. It can automatically select different purification paths based on the gas detection results, providing comprehensive purification methods. It can effectively purify the main gaseous impurities in sulfur hexafluoride gas, improve purification efficiency, and make the purified SF6 meet the new gas standards. The entire process is controlled by the control module to select the path, requiring less manual intervention and improving work efficiency. It can complete all the work tasks of sulfur hexafluoride gas purification without the need for other detection instruments or purification equipment, thus reducing workload.

[0074] Example 2:

[0075] like Figure 1 As shown, this embodiment, based on embodiment one, also includes a vacuum component 8; the vacuum component 8 is mainly used for vacuuming before the first operation to avoid interference from impurity gases.

[0076] Vacuum assembly 8 includes a vacuum pump 81 and a vacuum gauge 82. The vacuum pump 81 is connected to the rear end of the polymer membrane 71 through a solenoid valve V17, and the vacuum gauge 82 is connected to the rear end of the polymer membrane 71 through a solenoid valve V18. During operation, the solenoid valves V17 and V18 are opened to keep the gas path inside the device open, and the vacuum pump 81 is turned on. The extracted gas is discharged from the vacuum exhaust port. The vacuum gauge 82 detects the vacuum level inside the device to determine the progress of the vacuuming operation.

[0077] Example 3:

[0078] This embodiment discloses a method for a fully automated SF6 purification and refining device for detecting impurity gases, including the following steps:

[0079] Step 1: When the sulfur hexafluoride cylinder 11 to be purified is placed upside down on the support of the weighing device 12, set the weight M of the sulfur hexafluoride cylinder 11 on the weighing device 12 to akg (generally 45-55kg, or preset based on experience). Open the valve of the sulfur hexafluoride cylinder 11. When the cylinder weight is greater than a, open the solenoid valve V1 and close the solenoid valve V11. The liquid sulfur hexafluoride is depressurized by the first pressure reducing valve 13 and then vaporized by the first vaporizer 21 before entering the gas storage tank 22.

[0080] Step 2: Some of the gas in the gas storage tank 22 also enters the first gas detection module 24 to detect the content of impurity gases; according to the concentration of SO2, CF4 and C2F6 detected by the first gas detection module 24, the gas after depressurization and detection enters the first buffer tank 25, and selectively enters one or more of the alkaline solution treatment module 31, adsorption module 32 and first refrigeration module 33.

[0081] Step 3: Purification and Refinement Path Selection:

[0082] Based on the test results, there are three scenarios: ① Only SO2 concentration is too high; ② Only CF4 or C2F6 concentration is too high; ③ Both SO2 and CF4 or C2F6 concentrations are too high; ④ SO2, CF4 and C2F6 concentrations all meet the requirements.

[0083] ① If SO2 concentration is too high only: Solenoid valve V3 opens and solenoid valve V4 closes. The gas passes through an alkaline solution tank to remove acidic substances. The liquid in the alkaline solution tank can be 1% NaOH solution or 2% KOH solution (or other commonly used alkaline solutions). Then, solenoid valve V7 is opened, and the gas flows sequentially through desiccant adsorption tower 321, molecular sieve adsorption tower 322, and activated carbon adsorption tower 323 to remove gaseous impurities such as water, SO2, and C3F8. The purified gas enters the third pressure reducing valve 41 through solenoid valve V9. The concentrations of water, SO2, and CF4 in the gas are detected by the second gas detection module 42. The gas after pressure reduction by the third pressure reducing valve 41 and the gas detected by the second gas detection module 42 enter the second buffer tank 43.

[0084] ② Only when the CF4 concentration is too high: Solenoid valve V3 opens and solenoid valve V4 closes, allowing the gas to bypass the alkali pool and directly enter the desiccant adsorption tower 321, molecular sieve adsorption tower 322, and activated carbon adsorption tower 323; at this time, solenoid valve V9 closes and solenoid valves V8 and V10 open, allowing the gas to enter the first refrigeration tank 333, where it is cooled to -40℃ by the first refrigerator 331. At this point, sulfur hexafluoride is in a liquid state, while CF4 and C2F6 are in a gaseous state; the liquid sulfur hexafluoride is vaporized by the second vaporizer 34, and the vaporized gas is depressurized by the third pressure reducing valve 41 before being detected by the second gas detection module. Block 42 detects the concentrations of water, SO2, CF4, and C2F6 in the gas. The gas after pressure reduction by the third pressure reducing valve 41 and the gas after detection by the second gas detection module 42 enter the second buffer tank 43. The gas phase of the first refrigeration tank 333 contains a small amount of sulfur hexafluoride. The preset liquid level value is hm. When a portion of the liquid sulfur hexafluoride in the first refrigeration tank 333 is released, that is, when the first liquid level gauge 332 detects that the liquid level in the first refrigeration tank 333 is lower than h, the solenoid valve V10 is closed and the solenoid valve V6 is opened to introduce the gas into the first buffer tank 25 for continued circulation and purification.

[0085] The reason for controlling the flow of a portion of liquid sulfur hexafluoride before opening solenoid valve V6 to guide the gas into the first buffer tank 25 for continued purification is as follows: When refrigeration in the first refrigeration tank 333 ends, gas and liquid coexist within it. A portion of the liquid sulfur hexafluoride flows out through the bottom pipe of the first refrigeration tank 333. If all the liquid were to flow out, the gaseous sulfur hexafluoride would also flow out along the liquid pipe. Since the gaseous sulfur hexafluoride contains many impurities, the purification result would not meet the standards. Therefore, after most of the liquid in the first refrigeration tank 333 has flowed out, the remaining small portion of liquid and a large amount of gaseous sulfur hexafluoride are guided back for further purification.

[0086] ③ If the concentrations of SO2 and CF4 or C2F6 are both too high: close solenoid valves V4 and V9. The gas passes sequentially through the alkaline solution tank, desiccant adsorption tower 321, molecular sieve adsorption tower 322, activated carbon adsorption tower 323, and the first refrigeration tank 333. Similarly, after the gas is depressurized by the third pressure reducing valve 41, it enters the second buffer tank 43. Part of it is also detected by the second gas detection module 42 and then enters the second buffer tank 43. The gas in the first refrigeration tank 333 continues to circulate and be purified in accordance with the second situation.

[0087] ④ The concentrations of SO2, CF4 and C2F6 all meet the requirements: Solenoid valves V3 and V8 are closed, solenoid valve V4 is open, and the gas only passes through the desiccant adsorption tower 321, molecular sieve adsorption tower 322 and activated carbon adsorption tower 323. Similarly, after the gas is depressurized by the third pressure reducing valve 41, it enters the second buffer tank 43. Part of it is also entered into the second buffer tank 43 after being detected by the second gas detection module 42.

[0088] Step 4: Sulfur hexafluoride residual gas treatment:

[0089] When the mass of sulfur hexafluoride cylinder 11 is detected to drop below a kg, solenoid valve V1 is closed and solenoid valve V11 is opened to enter the second purification path.

[0090] When the second purification path is activated, initially there is a large amount of residual gas in the sulfur hexafluoride cylinder 11, and the pressure is also high. At this time, solenoid valve V12 is opened and solenoid valve V13 is closed, and the third compressor 61 is also shut down. Due to the pressure difference, the gas automatically enters the subsequent detection unit (the detection unit requires that the pressure is not too high, so a fourth pressure reducing valve 62 is designed). When the gas in the sulfur hexafluoride cylinder 11 is almost exhausted, the internal pressure of the sulfur hexafluoride cylinder 11 is insufficient to guide the gas into the subsequent detection module. At this time, electronic valve V12 is closed, electronic valve V13 is opened, and the third compressor 61 is turned on to extract the last bit of gas remaining in the sulfur hexafluoride cylinder 11, and the sulfur hexafluoride cylinder 11 is evacuated to ensure that all the gas in the sulfur hexafluoride cylinder 11 is completely purified.

[0091] After the gas enters the third gas detection module 63, the concentrations of nitrogen, SO2, CF4 and C2F6 are detected by the third gas detection module 63.

[0092] If the nitrogen concentration is too high, solenoid valve V14 is closed, and solenoid valves V5, V15, and V16 are opened. After the polymer membrane 71 separates the nitrogen, the fourth compressor 72 pressurizes and delivers the separated sulfur hexafluoride gas to the back end of the first compressor 26. According to the detection results of SO2, CF4, and C2F6 concentrations of the third gas detection module 63, the gas is purified according to the purification path in step three.

[0093] If the nitrogen concentration is within acceptable limits, skip the membrane separation step, open solenoid valves V5 and V14, and close solenoid valves V15 and V16. Purify and refine the gas according to the purification path in step three based on the detection results of SO2, CF4, and C2F6 concentrations from the third gas detection module 63.

[0094] Step 5: Liquefaction Filling:

[0095] If the second detection module 42 detects the gas and it passes the test, the solenoid valve V20 is opened, and the second compressor 44 pressurizes the sulfur hexafluoride gas in the second buffer tank 43 and transfers it to the second refrigeration module 51 to cool it to -40°C. Then, valve V21 is opened, and the gas is pumped into the cylinder 522 to be filled via the liquid pump 521. After the liquid filling is completed, a small amount of sulfur hexafluoride gas still remains in the second refrigeration module 51. The solenoid valve V2 is opened, and the gas enters the first buffer tank 25 for further circulation and purification. Additionally, the second weighing device 523 can be used to determine whether the cylinder is full.

[0096] If the gas fails the test by the second gas detection module 42, the solenoid valve V19 is opened and the solenoid valve V20 is closed. The second compressor 44 pressurizes the gas and transmits it to the gas storage tank 22 for continued circulation and purification until the second gas detection module 42 detects the gas and then liquefies and fills it.

[0097] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fully automated SF6 purification and refining device for detecting impurity gases, characterized in that, It includes a control module, and an air intake assembly, an air storage tank, a first gas detection module, a first buffer tank, a first purification unit, a second gas detection module, a second buffer tank, a back-end processing unit, a third gas detection module, a third buffer tank, and a second purification unit that are electrically connected to the control module; The air intake assembly includes a gas cylinder, a first weighing device, and a first pressure reducing valve. The gas cylinder is connected upside down to the first weighing device, and the first pressure reducing valve is connected to the gas cylinder. The outlet of the first pressure reducing valve is divided into two paths. The air intake assembly is divided into two paths: a first purification path and a second purification path. The first purification path is connected sequentially through a pipeline to a gas storage tank, a first gas detection module, a first buffer tank, a first purification unit, a second gas detection module, a second buffer tank, and a back-end processing unit. The second buffer tank is also connected to the first buffer tank through a pipeline. The second purification path is connected sequentially through a pipeline to a third gas detection module, a third buffer tank, and a second purification unit. The air intake and outlet of the second purification unit are also connected to the pipeline between the first buffer tank and the first purification unit. It also includes a first vaporizer, a second pressure reducing valve, and a first compressor. The first vaporizer is connected to the inlet end of the gas storage tank, and the outlet end of the gas storage tank is connected to the second pressure reducing valve. The first gas detection device is connected in parallel to the gas pipeline at the outlet end of the second pressure reducing valve. The first compressor is connected to the outlet end of the first buffer tank, and the outlet end of the first compressor is connected to the alkaline solution treatment module and the adsorption module. The first purification unit includes an alkaline solution treatment module, an adsorption module, and a first refrigeration module that can be connected in parallel and in series; the second purification unit is a polymer membrane, and the outlet of the second purification unit is also connected to a vacuum component.

2. The SF6 purification and refining device for fully automatic impurity gas detection according to claim 1, characterized in that, The adsorption module includes at least three adsorption towers connected in series, at least one of which is a desiccant adsorption tower, at least one of which is a molecular sieve adsorption tower, and at least one of which is an activated carbon adsorption tower.

3. The SF6 purification and refining device for fully automatic impurity gas detection according to claim 1, characterized in that, It also includes a third pressure reducing valve and a second compressor. The third pressure reducing valve is connected to the outlet of the first purification unit. The second gas detection module is connected in parallel to the outlet pipe of the third pressure reducing valve. The second buffer tank is connected to the outlet of the second gas detection module. The second compressor is connected to the outlet of the second buffer tank.

4. The SF6 purification and refining device for fully automatic impurity gas detection according to claim 3, characterized in that, The back-end processing unit includes a second refrigeration module and a filling unit. The second refrigeration module is connected to the outlet of the second compressor, and the filling unit is connected to the second refrigeration module. The second refrigeration module is also connected to a gas storage tank through a pipeline.

5. The fully automated SF6 purification and refining device for detecting impurity gases according to claim 1, characterized in that, It also includes a second vaporizer, which is connected to the outlet of the first refrigeration module and located at the inlet of the third gas detection module.

6. The method of SF6 purification and refining apparatus using any one of claims 1-5 for fully automatic impurity gas detection, characterized in that, Includes the following steps: Step 1: When the weight of the gas cylinder to be purified is greater than the preset weight M of the control module, the first purification route is entered, and the liquid sulfur hexafluoride enters the storage tank after depressurization and vaporization. Step 2: After the gas in the storage tank is depressurized again, it enters the first buffer tank. Some of the gas in the storage tank also enters the first gas detection module to detect the content of impurity gases. Step 3: Based on the impurity gas detection results detected by the first gas detection module, selectively enter one or more of the alkaline solution treatment module, adsorption module, and first refrigeration module; Step 4: When the weight of the gas cylinder to be purified is less than the preset weight M of the control module, it enters the second purification route. After depressurization, the gas enters the third buffer tank. After depressurization, part of the gas also enters the third gas detection module to detect the content of impurity gas. According to the impurity gas detection results of the third gas detection module, it selectively enters the second purification unit or directly enters the outlet of the first buffer tank and then selectively enters one or more of the alkaline treatment module, adsorption module, and first refrigeration module. Step 5: The purified gas is tested again by the second gas detection module. If the gas passes the test, it is liquefied and bottled by the back-end processing unit. If the gas fails the test, it is returned to the storage tank for continued purification.

7. The SF6 purification and refining method for fully automated impurity gas detection according to claim 6, characterized in that, In step three, if only the SO2 concentration exceeds the preset value, the gas passes through the alkali treatment module and the adsorption module in sequence; if only the CF4 concentration exceeds the preset value, the gas directly enters the adsorption module and then the first refrigeration module; if both the SO2 and CF4 or C2F6 concentrations exceed the preset values, the gas passes through the alkali treatment module, the adsorption module, and the first refrigeration module in sequence; if the SO2, CF4, and C2F6 concentrations all meet the requirements, the gas only passes through the adsorption module. In step five, if the nitrogen concentration exceeds a preset value, the gas enters the second purification unit and then the outlet of the first buffer tank. Based on the detection results of SO2, CF4, and C2F6 concentrations detected by the third gas detection module, it selectively enters one or more of the alkali treatment module, adsorption module, and first refrigeration module. If the nitrogen concentration is qualified, the gas directly enters the outlet of the first buffer tank. Based on the detection results of SO2, CF4, and C2F6 concentrations detected by the third gas detection module, it selectively enters one or more of the alkali treatment module, adsorption module, and first refrigeration module.

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