Electrochemical device for degrading sulfur hexafluoride waste gas

Abstract

The utility model discloses an electrochemical device for degrading sulfur hexafluoride waste gas, which comprises an electrolytic tank, two washing components, a cathode region, an anode region and a cation exchange membrane for separating the cathode region and the anode region, a cathode is arranged in the cathode region, an anode is arranged in the anode region, and a cathode is arranged in the anode region. The cathode and the anode are electrically connected with a negative electrode and a positive electrode of a direct-current power supply respectively; the washing assembly comprises washing columns and a spraying assembly, the two washing columns are communicated with the cathode area and the anode area respectively, the washing column of the cathode area is communicated with the anode area through a gas pipeline, and the spraying assembly is connected with the washing columns and the cathode area or the anode area. And the spraying assembly is used for extracting electrolyte and spraying the electrolyte into the washing column. The device can be used for carrying out countercurrent washing on dissipated or incompletely degraded SF6 and other intermediate gas products, so that deep degradation of SF6 is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of sulfur hexafluoride waste gas degradation, in particular to an electrochemical device for degrading sulfur hexafluoride waste gas. Background Art

[0002] Sulfur hexafluoride (SF6) gas is widely used in electricity, metallurgy, transportation and other industries due to its excellent insulation and arc extinguishing properties. However, SF6 is also the strongest greenhouse gas known to mankind, with a global warming potential (GWP) of up to 23,900 times that of carbon dioxide. SF6 is a difficult-to-degrade greenhouse gas, and the lifespan of SF6 emitted into the atmosphere is about 3,400 years, making its accumulation in the atmosphere irreversible. Therefore, reducing SF6 gas emissions is of great significance to supporting my country in achieving its greenhouse gas emission reduction goals and realizing "carbon peak and carbon neutrality" as soon as possible. Realizing efficient degradation of SF6 waste gas is one of the main ways to reduce its emissions.

[0003] Patent CN114657582A discloses an electrochemical degradation method for SF6 waste gas, the method comprising: assembling an electrolytic cell, the electrolytic cell comprising an anode region, a cathode region, and a diaphragm for separating the anode region and the cathode region; wherein the anode region adopts a Pt mesh electrode as an anode, and the electrolyte in the anode chamber comprises AgNO3 and H2SO4 solutions; the cathode region adopts a Cu electrode as a cathode, a saturated calomel electrode as a reference electrode, and the electrolyte in the cathode chamber comprises a nickel cyanide complex and a KOH solution; the cathode region is filled with SF6 waste gas; the anode, the cathode and the reference electrode are pressurized to perform an electrolytic reaction, and gas phase products and liquid phase products are collected for analysis.

[0004] However, the solubility of SF6 in the electrolyte in the above-mentioned prior art is relatively low. After SF6 is diluted with a large amount of inert gas such as argon (Ar) and passed into the electrolytic cell, it is directly degraded by simply being energized. As a result, SF6 that has not been completely degraded and other intermediate products are prone to escape during the reaction, posing a certain risk of pollution. Utility Model Content

[0005] The purpose of the utility model is to overcome the above technical deficiencies and propose an electrochemical device for degrading sulfur hexafluoride waste gas, so as to solve the technical problem that in the prior art, the solubility of SF6 in the electrolyte is relatively low, SF6 is diluted with a large amount of inert gas such as argon (Ar) and then directly degraded by simply energizing the electrolytic cell, so that SF6 that has not been completely degraded and other intermediate products are easy to escape during the reaction process, resulting in certain pollution.

[0006] In order to achieve the above technical purpose, the utility model adopts the following technical solutions:

[0007] The utility model provides an electrochemical device for degrading sulfur hexafluoride waste gas, comprising:

[0008] An electrolytic cell comprising a cathode region, an anode region and a cation exchange membrane separating the cathode region and the anode region, wherein a cathode is disposed in the cathode region, an anode is disposed in the anode region, and the cathode and the anode are electrically connected to a negative electrode and a positive electrode of a DC power supply, respectively; and

[0009] Two washing components, the washing components include washing columns and spray components, the two washing columns are connected to the cathode area and the anode area respectively, the washing column in the cathode area is connected to the anode area through a gas pipeline, the spray component connects the washing column and the cathode area or the anode area, and the spray component is used to extract electrolyte and spray it into the washing column.

[0010] In some embodiments, the gas pipeline includes a first pipeline and a second pipeline;

[0011] The electrochemical device for degrading sulfur hexafluoride waste gas also includes a first three-way valve and a third pipeline, wherein the first pipeline is respectively connected to the washing column corresponding to the cathode area and the inlet of the first three-way valve, the second pipeline is respectively connected to one of the outlets of the first three-way valve and the anode area, and the third pipeline is respectively connected to the other outlet of the first three-way valve and the cathode area.

[0012] In some embodiments, the electrochemical device for degrading sulfur hexafluoride waste gas also includes a second three-way valve, a fourth pipe, a fifth pipe and a sixth pipe, wherein the fourth pipe is respectively connected to the washing column corresponding to the anode area and the inlet of the second three-way valve, the fifth pipe is connected to one of the outlets of the second three-way valve and the anode area, and the sixth pipe is respectively connected to the other outlet of the second three-way valve and the outside world.

[0013] In some embodiments, the electrochemical device for degrading sulfur hexafluoride waste gas also includes a third three-way valve, which is arranged in the spray assembly corresponding to the anode area, so that the spray assembly can selectively transport electrolyte to one of the washing column and the outside world.

[0014] In some embodiments, the washing column is filled with polytetrafluoroethylene filler; and / or,

[0015] The second pipeline, the third pipeline and the fifth pipeline are all provided with a check valve.

[0016] In some embodiments, the electrochemical device for degrading sulfur hexafluoride waste gas also includes a gas supply unit, which includes a first gas cylinder, a second gas cylinder and a gas mixing component, the first gas cylinder is connected to the gas mixing component through a pipeline, the first gas cylinder is used to store sulfur hexafluoride, the second gas cylinder is connected to the gas mixing component through a pipeline, the second gas cylinder is used to store carrier gas, the gas mixing component is connected to the cathode area through a pipeline, and the gas mixing component is used to evenly mix sulfur hexafluoride and carrier gas.

[0017] In some embodiments, the gas mixing component includes a warm water bath and a gas mixing buffer box, the warm water bath is filled with warm water, the gas mixing buffer box is immersed in the warm water, the first gas cylinder and the second gas cylinder are connected to the inlet of the gas mixing buffer box, and the outlet of the gas mixing buffer box is connected to the cathode area.

[0018] In some embodiments, a flow channel for gas to pass through is provided in the gas mixing buffer box, and the flow channel is arranged in a winding manner.

[0019] In some embodiments, the pipelines connecting the first gas cylinder and the second gas cylinder to the gas mixing buffer box are both provided with a pressure reducing valve, a flow meter and a solenoid valve, and the pipeline connecting the gas mixing buffer box to the cathode area is provided with a flow meter and a check valve.

[0020] In some embodiments, the spray assembly includes a spray head and an electromagnetic pump, the spray head is located at the top of the washing column, and the electromagnetic pump is connected to the spray head and the cathode region respectively.

[0021] Compared with the prior art, the utility model provides an electrochemical device for degrading sulfur hexafluoride waste gas, wherein the electrolytic cell comprises a cathode region and an anode region, wherein a cathode is arranged in the cathode region, and an anode is arranged in the anode region, wherein the cathode and the anode are respectively electrically connected to the negative electrode and the positive electrode of a direct current power supply; wherein both the cathode region and the anode region are connected to the washing column, and the washing column in the cathode region is connected to the anode region through a gas pipeline, and the spray assembly sprays electrolyte into the washing column, and the gas flows in the direction of entering the cathode region, reacting with the electrolyte in the cathode region, and then entering the cathode region to connect to the washing column, and then entering the anode region through the gas pipeline, and reacting with the electrolyte in the anode region, and then entering the washing column connected to the anode region. The spray assembly can draw electrolyte into the washing column as spray liquid, and can perform countercurrent washing on the escaped or incompletely degraded SF6 and other intermediate gas products (SOF2, SF4, OF2, etc.), so as to achieve deep degradation of SF6. The coordinated use of the electrolytic cell and the washing column solves the problem of SF6 and other intermediate gas products (SOF2, SF4, OF2, etc.) escaping directly without being completely degraded due to their low solubility in the electrolyte. On the one hand, the degradation effect of the exhaust gas is further guaranteed, and on the other hand, the restrictions on the intake volume and intake SF6 concentration are reduced to a certain extent, so that SF6 with a higher intake concentration can also be effectively degraded in the device, and the processing capacity of the device is greatly improved.

[0022] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model and implement it according to the contents of the specification, the preferred embodiment of the utility model is described in detail as follows with the accompanying drawings. The specific implementation method of the utility model is given in detail by the following embodiments and their drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of an embodiment of an electrochemical device for degrading sulfur hexafluoride waste gas provided by the utility model.

[0024] Description of reference numerals:

[0025] 1-cathode area, 2-anode area, 3-cation exchange membrane, 4-cathode, 5-anode, 6-DC power supply, 7-washing column, 8-spray assembly, 9-gas pipeline; 10-first three-way valve, 11-second three-way valve, 12-third three-way valve, 13-first gas cylinder, 14-second gas cylinder, 15-warm water bath, 16-gas mixing buffer box, 17-pressure reducing valve, 18-flow meter, 19-solenoid valve, 20-check valve. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0027] In order to solve the problem that the solubility of SF6 in the electrolyte is relatively low in the prior art, SF6 is diluted with a large amount of inert gas such as argon (Ar) and then introduced into the electrolytic cell for simple energization and degradation, which makes it easy for SF6 and other intermediate products that have not been completely degraded to escape during the reaction, resulting in certain pollution. The utility model provides an electrochemical device for degrading sulfur hexafluoride waste gas, which can perform countercurrent washing on the escaped or incompletely degraded SF6 and other intermediate gas products (SOF2, SF4, OF2, etc.), thereby achieving deep degradation of SF6. The coordinated use of the electrolytic cell and the washing column solves the problem that SF6 and other intermediate gas products (SOF2, SF4, OF2, etc.) directly escape without being completely degraded due to their low solubility in the electrolyte. On the one hand, the degradation effect of the waste gas is further guaranteed, and on the other hand, the restrictions on the intake volume and the intake SF6 concentration are reduced to a certain extent, so that SF6 with a higher intake concentration can also be effectively degraded in the device, and the processing capacity of the device is greatly improved.

[0028] See also Figure 1 , Figure 1 This is a schematic structural diagram of an electrochemical device for degrading sulfur hexafluoride waste gas in one embodiment of the utility model.

[0029] In order to achieve the above technical purpose, the utility model adopts the following technical solutions:

[0030] The utility model provides an electrochemical device for degrading sulfur hexafluoride waste gas, comprising an electrolytic cell and two washing components, comprising a cathode area 1, an anode area 2 and a cation exchange membrane 3 separating the cathode area 1 and the anode area 2, wherein a cathode 4 is arranged in the cathode area 1, an anode 5 is arranged in the anode area 2, and the cathode 4 and the anode 5 are respectively electrically connected to the negative electrode and the positive electrode of a direct current power supply 6; the washing component comprises a washing column 7 and a spray component 8, the two washing columns 7 are respectively connected to the cathode area 1 and the anode area 2, the washing column 7 of the cathode area 1 is connected to the anode area 2 through a gas pipeline 9, the spray component 8 connects the washing column 7 and the cathode area 1 or the anode area 2, and the spray component 8 is used to extract electrolyte and spray it into the washing column 7.

[0031] In this embodiment, the electrolytic cell includes a cathode area 1 and an anode area 2, wherein a cathode 4 is provided in the cathode area 1, and an anode 5 is provided in the anode area 2, wherein the cathode 4 and the anode 5 are electrically connected to the negative electrode and the positive electrode of a DC power supply 6, respectively; the cathode area 1 and the anode area 2 are both connected to the washing column 7, and the washing column 7 of the cathode area 1 is connected to the anode area 2 through a gas pipeline 9, and the spray assembly 8 sprays electrolyte into the washing column 7, and the gas flows in the direction of entering the cathode area 1, reacting with the electrolyte in the cathode area 1, and then entering the cathode area 1 to connect to the washing column 7, and then entering the anode area 2 through the gas pipeline 9, and reacting with the electrolyte in the anode area 2, and then entering the washing column 7 connected to the anode area 2. The spray assembly 8 can draw electrolyte into the washing column 7 as spray liquid, and can perform countercurrent washing on the escaped or incompletely degraded SF6 and other intermediate gas products (SOF2, SF4, OF2, etc.), so as to achieve deep degradation of SF6. The coordinated use of the electrolytic cell and the washing column 7 solves the problem of SF6 and other intermediate gas products (SOF2, SF4, OF2, etc.) escaping directly without being completely degraded due to their low solubility in the electrolyte. On the one hand, the degradation effect of the exhaust gas is further guaranteed. On the other hand, the restrictions on the intake volume and the intake SF6 concentration are reduced to a certain extent, so that SF6 with a higher intake concentration can also be effectively degraded in the device, and the processing capacity of the device is greatly improved.

[0032] It can be understood that the cathode area 1 and the anode area 2 are both relatively sealed spaces, in which electrolyte is provided, and the electrolyte between the two is separated by the cation exchange membrane 3. The washing column 7 is a cylindrical structure as a whole, and its lower end is connected to the cathode area 1 or the anode area 2, and the gas in the cathode area 1 and the anode area 2 can enter the washing column 7.

[0033] For ease of explanation, in this embodiment, the two washing columns 7 are respectively the first washing column and the second washing column, the two spray assemblies 8 are respectively the first spray assembly and the second spray assembly, the lower end of the first washing column is connected to the cathode area 1, the upper end of the first washing column is connected to the anode area 2 through the gas pipeline 9, the lower end of the second washing column is connected to the anode area 2, the upper end of the second washing column is connected to the outside, the first spray assembly is respectively connected to the cathode area 1 and the first washing column, the first spray assembly can extract the electrolyte of the cathode area 1 and spray it into the first washing column, the second spray assembly is respectively connected to the anode area 2 and the second washing column, the second spray assembly can extract the electrolyte of the anode area 2 and spray it into the second washing column, and the gas flow direction is that the SF6 gas first enters the In the cathode area 1, it reacts with the electrolyte in the cathode area 1 to generate intermediate gas products (SOF2, SF4, OF2, etc.), and these intermediate gases and incompletely degraded SF6 enter the first washing tower. The first spray component draws the electrolyte in the cathode area 1 and sprays it into the first washing tower, so that the incompletely degraded SF6 continues to react with the electrolyte, thereby completely degrading to generate intermediate gas products. Finally, the intermediate gas products enter the anode area 2 through the gas pipeline 9, and react again with the electrolyte in the anode area 2 to generate harmless tail gas. The harmless tail gas and incompletely degraded intermediate gas enter the second washing column. The second spray component draws the electrolyte in the anode area 2 and sprays it into the second washing tower, completely degrading the incompletely degraded intermediate gas and discharging it from the second washing tower.

[0034] In this embodiment, the electrolytic cell is a typical H-type electrolytic cell. The main bodies of the electrolytic cell and the washing column 7 are made of corrosion-resistant quartz glass, and corrosion-resistant materials such as polytetrafluoroethylene can also be selected. The height of the electrolytic cell is about 400 mm, and the diameters of the cathode area 1 and the anode area 2 are equal, about 350 mm; the height of the washing column 7 is about 1200 mm and the diameter is about 80 mm. The cathode 4 is a copper electrode (which can be replaced by other stable conductive materials), the anode 5 is a platinum electrode (which can be replaced by other inert electrodes), and the cation exchange membrane 3 is a Nafion117 type cation exchange membrane 3 (which can be replaced by Nafion32 / Nafion212 / Nafion115 and other diaphragms). The copper electrode and the platinum electrode are respectively connected to the negative electrode and the positive electrode of the DC regulated power supply, and the working voltage of the DC regulated power supply is 3.7-5.0 V. The electrolyte in the cathode area 1 is a potassium hydroxide solution containing a nickel cyanide complex, wherein [Ni(CN)4] 2- ≈40mM, pH≈13; the electrolyte of the anode region 2 is a sulfuric acid solution containing silver ions, wherein Ag +≈25mM, pH≈1; the electrolyte with the above concentration ratio can efficiently capture the waste gas to be degraded, maintain the active components of SF6 degradation - homogeneous low-valent Ni(Ⅰ) and high-valent Ag(Ⅱ) for consistent and efficient electrogeneration during the power-on process, and ensure the continuous and efficient electrochemical degradation of the system.

[0035] In one embodiment, the gas pipeline 9 includes a first pipeline and a second pipeline; the electrochemical device for degrading sulfur hexafluoride waste gas also includes a first three-way valve 10 and a third pipeline, the first pipeline is respectively connected to the washing column 7 corresponding to the cathode area 1 and the inlet of the first three-way valve 10, the second pipeline is respectively connected to one of the outlets of the first three-way valve 10 and the anode area 2, and the third pipeline is respectively connected to the other outlet of the first three-way valve 10 and the cathode area 1.

[0036] In this embodiment, the first three-way valve 10 is an L-shaped three-way ball valve, that is, the first three-way valve 10 is provided with an inlet and two outlets, and the inlet can be connected to one of the two outlets. The inlet of the first three-way valve 10 is connected to the first washing column through the first pipe, and one outlet of the first three-way valve 10 is connected to the anode area 2 through the second pipe. The other outlet of the first three-way valve 10 is connected to the cathode area 1 through the third pipe. In specific use, when the content of incompletely degraded SF6 entering the first washing column is high and the first spray assembly cannot degrade it at one time, the first three-way valve 10 can be controlled to connect the first pipe and the third pipe, so that the gas in the first washing column is passed into the cathode area 1 again, and continues to react with the electrolyte in the cathode area 1. After multiple cycles, until the SF6 gas is completely degraded, the first three-way valve 10 is controlled to connect the first pipe and the second pipe, and the gas in the first washing column is passed into the anode area 2. Such a setting can completely degrade the SF6 gas and prevent the SF6 gas from escaping and polluting the environment.

[0037] In one embodiment, the electrochemical device for degrading sulfur hexafluoride waste gas also includes a second three-way valve 11, a fourth pipeline, a fifth pipeline and a sixth pipeline, the fourth pipeline respectively connects the washing column 7 corresponding to the anode area 2 and the inlet of the second three-way valve 11, the fifth pipeline connects one of the outlets of the second three-way valve 11 and the anode area 2, and the sixth pipeline respectively connects the other outlet of the second three-way valve 11 and the outside.

[0038] In the present embodiment, the second three-way valve 11 is also an L-shaped three-way ball valve, the inlet of the second three-way valve 11 is connected to the second washing column through the fourth pipe, one outlet of the second three-way valve 11 is connected to the cathode area 1 through the fifth pipe, and the other outlet of the second three-way valve 11 is connected to the outside through the sixth pipe. The second three-way valve 11 can control the fourth pipe to be connected to the fifth pipe or the sixth pipe. In specific use, when the content of the intermediate gas entering the second washing tower is high and cannot be degraded at one time, the second three-way valve 11 can be controlled to connect the fourth pipe with the fifth pipe, so that the gas in the second washing column enters the anode area 2 again for reaction. After multiple cycles until the intermediate gas is completely degraded, the second three-way valve 11 is controlled again to connect the fourth pipe with the sixth pipe to discharge the harmless tail gas. Such a setting can completely degrade the intermediate gas and avoid polluting the environment.

[0039] In one of the embodiments, the electrochemical device for degrading sulfur hexafluoride waste gas also includes a third three-way valve 12, and the third three-way valve 12 is arranged in the spray assembly 8 corresponding to the anode area 2, so that the spray assembly 8 can selectively transport electrolyte to one of the washing column 7 and the outside world.

[0040] In this embodiment, the third three-way valve 12 is an L-type three-way ball valve, the electromagnetic pump in the second spray assembly is connected to the inlet of the third three-way valve 12, one outlet of the third three-way valve 12 is connected to the spray head of the second spray assembly, and the other outlet of the third three-way valve 12 is connected to the outside world. When the intermediate gas reacts with the electrolyte in the anode area 2, the fluoride ion concentration in the electrolyte will increase, and the fluorine resources can be recycled. Therefore, the fluoride ion-rich electrolyte can be regularly discharged through the electromagnetic pump according to the operating conditions to achieve the recycling of fluorine resources. In addition, an electrolyte replenishing port is provided on the electrolytic cell of the anode area 2 to facilitate regular replenishment of electrolyte and ensure efficient and sustainable operation of the system.

[0041] In one embodiment, the washing column 7 is filled with polytetrafluoroethylene filler.

[0042] In one embodiment, the second pipeline, the third pipeline and the fifth pipeline are all provided with a check valve 20 .

[0043] In this embodiment, by providing the check valves 20 on the second pipeline, the third pipeline and the fifth pipeline, it is possible to prevent the electrolyte from being sucked back due to pressure fluctuations, thereby avoiding the risk of corrosion of the pipelines and related parts.

[0044] In one of the embodiments, the electrochemical device for degrading sulfur hexafluoride waste gas also includes a gas supply unit, which includes a first gas cylinder 13, a second gas cylinder 14 and a gas mixing component. The first gas cylinder 13 is connected to the gas mixing component through a pipeline, and the first gas cylinder 13 is used to store sulfur hexafluoride. The second gas cylinder 14 is connected to the gas mixing component through a pipeline, and the second gas cylinder 14 is used to store a carrier gas. The gas mixing component is connected to the cathode area 1 through a pipeline, and the gas mixing component is used to evenly mix sulfur hexafluoride and the carrier gas.

[0045] In this embodiment, since high-concentration SF6 gas cannot be completely degraded when directly introduced into the cathode area 1, it is necessary to mix the SF6 gas with a carrier gas (argon, nitrogen and other inert gases) to reduce its concentration. The first gas cylinder 13 and the second gas cylinder 14 are both connected to the gas mixing component. The first gas cylinder 13 introduces SF6 gas into the gas mixing component, and the second gas cylinder 14 introduces carrier gas into the gas mixing component. The air inlet pipelines of SF6 gas and carrier gas are connected in parallel. The carrier gas can be an inert gas such as argon and nitrogen. The concentration of SF6 gas should not be too high. Generally, the volume fraction of the intake SF6 is controlled within 20%. In actual operation, it is necessary to adjust the intake flow rate according to the load of the subsequent reactor. The SF6 gas and the carrier gas are evenly mixed in the gas mixing component and then introduced into the cathode area 1. Such a setting can reduce the concentration of SF6 gas entering the cathode area 1.

[0046] In one embodiment, the gas mixing component includes a warm water bath box 15 and a gas mixing buffer box 16, the warm water bath box 15 is filled with warm water, the gas mixing buffer box 16 is immersed in the warm water, the first gas cylinder 13 and the second gas cylinder 14 are connected to the inlet of the gas mixing buffer box 16, and the outlet of the gas mixing buffer box 16 is connected to the cathode area 1.

[0047] In this embodiment, the gas mixing buffer box 16 is arranged in the warm water bath box 15. The warm water bath box 15 can heat the gas in the gas mixing buffer box 16, which can promote the thermal motion of the gas molecules, thereby further promoting the uniform mixing of SF6 and the carrier gas. A large-capacity gas mixing buffer box 16 is provided before the electrolysis reaction to have a buffering effect. The gas load in the subsequent electrochemical reaction zone fluctuates within a certain range. The provision of the gas mixing buffer box 16 helps to improve the adaptability of the entire device and ensure the flexibility and stability of the system operation.

[0048] In one embodiment, a flow channel for gas to pass through is provided in the gas mixing buffer box 16, and the flow channel is arranged in a zigzag manner.

[0049] In this embodiment, a plurality of guide plates are arranged in the gas mixing buffer box 16, and the plurality of guide plates are arranged at intervals along the gas flow direction. Among each two adjacent guide plates, one is connected to the top of the gas mixing buffer box 16, and the other is connected to the bottom of the gas mixing buffer box 16. By arranging a plurality of guide plates, a winding flow channel is formed in the gas mixing buffer box 16, and the mixed gas is guided to pass through the gas mixing buffer box 16 in an "S-shape", which can promote uniform mixing of the intake air.

[0050] In one embodiment, the pipelines connecting the first gas cylinder 13 and the second gas cylinder 14 to the gas mixing buffer box 16 are both provided with a pressure reducing valve 17, a flow meter 18 and a solenoid valve 19, and the pipeline connecting the gas mixing buffer box 16 to the cathode area 1 is provided with a flow meter 18 and a check valve 20.

[0051] In this embodiment, the air intake lines of sulfur hexafluoride and the carrier gas (argon, nitrogen and other inert gases) are independent of each other, and enter the mixed gas buffer box 16 after passing through the pressure reducing valve 17, the flow meter 18 and the solenoid valve 19 respectively. By setting the pressure reducing valve 17, the flow meter 18 and the solenoid valve 19, they can be flexibly adjusted to control the intake volume and the ratio of the mixed gas in real time.

[0052] In one embodiment, the spray assembly 8 includes a spray head and an electromagnetic pump. The spray head is located at the top of the washing column 7, and the electromagnetic pump is connected to the spray head and the cathode area 1 respectively.

[0053] In order to better understand the present invention, the following Figure 1 The technical solution of the utility model is described in detail:

[0054] In one embodiment, the initial electrolyte of the cathode region 1 is a potassium hydroxide solution containing a nickel cyanide complex, wherein [Ni(CN)4] 2- =45mM, pH=13.2; the initial electrolyte of the anode region 2 is a sulfuric acid solution containing silver ions, wherein Ag +=24mM, pH=1.0. Before the gas is introduced, the power supply is first turned on, the working voltage is 3.7V, and the gas is introduced after waiting for 10 minutes. Argon is selected as the carrier gas, and the initial intake flow rate of sulfur hexafluoride is controlled to be 9ml / min, and the initial intake flow rate of argon is 900ml / min. Sulfur hexafluoride and argon are simultaneously introduced into the mixed gas buffer box 16 for sufficient mixing. After 5 minutes, the mixed gas flow rate introduced into the electrolytic cell is stabilized at 885ml / min. The internal circulation of the electrolytic reaction zone is not turned on. After the exhaust gas passes through the cathode zone 1, the first washing column, the anode zone 2, and the second washing column, the final SF6 degradation rate of the exhaust gas reaches 97.6%, and the stable degradation effect can be maintained within 12 hours of continuous reaction. After testing, the tail gas does not contain toxic and harmful gases such as SO2F2, SOF2, and SOF4.

[0055] In another embodiment, the initial electrolyte in the cathode region 1 is a potassium hydroxide solution containing a nickel cyanide complex, wherein [Ni(CN)4] 2- =45mM, pH=13.2; the initial electrolyte of the anode region 2 is a sulfuric acid solution containing silver ions, wherein Ag + =24mM, pH=1.0. Before introducing the gas, first turn on the power supply with the working voltage of 3.7V, and start introducing the gas after waiting for 10 minutes. Select argon as the carrier gas, control the initial intake flow rate of sulfur hexafluoride to 9ml / min, and the initial intake flow rate of argon to 900ml / min. Sulfur hexafluoride and argon are simultaneously introduced into the mixed gas buffer box 16 for sufficient mixing. After 5 minutes, the mixed gas flow rate introduced into the electrolytic cell is stabilized at 885ml / min. Start the internal circulation unit of the electrolytic reaction zone, close the gas channels of the cathode zone 1 and the anode zone 2, and the exhaust gas is first circulated in the cathode zone 1. Stop introducing SF6 after 2 minutes, adjust the argon intake flow rate to 100ml / min, and after circulating in the cathode zone 1 for 5 minutes, adjust the first three-way valve 10 to open the The gas passage between the cathode area 1 and the anode area 2 is opened to allow the waste gas to enter the anode area 2 for further degradation, and the tail gas outlet of the second washing column is kept closed. After 5 minutes, the second three-way valve 11 is adjusted to open the tail gas outlet of the second washing column. After the tail gas is discharged, the tail gas outlet of the second washing column is closed, and the gas passage between the cathode area 1 and the anode area 2 is closed. SF6 is continued to be introduced, and the SF6 inlet flow rate is controlled to be 9ml / min. At the same time, the argon flow rate is adjusted to 900ml / min. After 3 minutes, the mixed gas flow rate introduced into the electrolytic cell is stabilized to 885ml / min, and the internal circulation operation of the above electrolytic reaction zone is repeated. Under this working condition, the final outgas SF6 degradation rate is higher than 99.5%, and a stable degradation effect can be maintained within 10 hours of continuous reaction. After testing, the tail gas does not contain toxic and harmful gases such as SO2F2, SOF2, and SOF4.

[0056] The main reaction zone of SF6 electrochemical degradation in this application consists of a classic H-type electrolytic cell and a washing column 7. The electrolyte of the electrolytic cell is extracted by an electromagnetic pump and then enters the washing column 7 as a spray liquid to countercurrently wash the SF6 and other intermediate gas products (SOF2, SF4, OF2, etc.) that escape or are not completely degraded, so as to achieve deep degradation of SF6. The organic combination of the electrolytic cell and the washing column 7 solves the problem of SF6 and other intermediate gas products (SOF2, SF4, OF2, etc.) escaping directly without being completely degraded due to their low solubility in the electrolyte. On the one hand, it further guarantees the degradation effect of the exhaust gas, and on the other hand, it reduces the restrictions on the intake volume and intake SF6 concentration to a certain extent, so that SF6 with a higher intake concentration can also be effectively degraded in the device, and the processing capacity of the device is greatly improved.

[0057] In the present application, a warm water bath gas mixing buffer zone is specially set after the gas distribution. The warm water bath accelerates the thermal motion of gas molecules, and the guide plate guides the gas molecules to collide and mix strongly, thereby ensuring the uniformity of the mixed gas. The gas mixing unit also serves as a buffer zone to improve the adaptability of the subsequent circulation device to gas flow fluctuations.

[0058] In the present application, L-type three-way ball valves are installed on the gas outlets of the cathode zone 1 and the anode zone 2. The gas after countercurrent washing can be adjusted to be selectively introduced into the electrolytic cell to enter a new degradation cycle. After a certain number of cycles, the L-type three-way ball valve is changed to enter the next reaction zone (cathode 4) or discharge the tail gas (anode 5). The adjustable multi-stage circulation degradation system constructed by the circulating gas path improves the tolerance of the electrochemical reaction zone to the SF6 load, overcomes the problem that various existing SF6 degradation devices have poor degradation effects on higher concentrations of SF6, and reduces the amount of carrier gas used. In actual operation, the number of cycles can be adjusted according to different intake concentrations of SF6, which can well ensure the continuous and efficient degradation of SF6 with different intake concentrations under continuous flow operation conditions, with a short degradation time and a high degradation rate.

[0059] In the present application, an L-shaped three-way ball valve is installed in the electrolyte circulation pipeline of the anode area 2, and the electrolyte rich in fluoride ions can be discharged regularly according to the operating conditions to achieve the recycling of fluorine resources.

[0060] In the present application, an electrolyte replenishing port is provided on the electrolytic cell of the anode region 2 to facilitate regular replenishment of electrolyte and ensure efficient and sustainable operation of the system.

[0061] In the present application, the circulating gas circuit and the air intake pipeline are not connected to each other, and the adjustment process is more flexible and independent.

[0062] In the present application, after the toxic gaseous electrolysis products in the cathode region 1 undergo an electrochemical oxidation reaction mediated by the anode region 2, the released tail gas does not contain any toxic gas products. The tail gas is mainly a high-purity carrier gas passed into the degradation device and can be recycled after being collected.

[0063] The specific implementation methods of the utility model described above do not constitute a limitation on the protection scope of the utility model. Any other corresponding changes and modifications made according to the technical concept of the utility model should be included in the protection scope of the claims of the utility model.

Claims

1. An electrochemical device for degrading sulfur hexafluoride waste gas, characterized in that: It includes: An electrolytic cell comprising a cathode region, an anode region and a cation exchange membrane separating the cathode region and the anode region, wherein a cathode is disposed in the cathode region, an anode is disposed in the anode region, and the cathode and the anode are electrically connected to a negative electrode and a positive electrode of a DC power supply, respectively; and Two washing components, the washing components include washing columns and spray components, the two washing columns are connected to the cathode area and the anode area respectively, the washing column in the cathode area is connected to the anode area through a gas pipeline, the spray component connects the washing column and the cathode area or the anode area, and the spray component is used to extract electrolyte and spray it into the washing column.

2. The electrochemical device for degrading sulfur hexafluoride waste gas according to claim 1, characterized in that: The gas pipeline includes a first pipeline and a second pipeline; The electrochemical device for degrading sulfur hexafluoride waste gas also includes a first three-way valve and a third pipeline, wherein the first pipeline is respectively connected to the washing column corresponding to the cathode area and the inlet of the first three-way valve, the second pipeline is respectively connected to one of the outlets of the first three-way valve and the anode area, and the third pipeline is respectively connected to the other outlet of the first three-way valve and the cathode area.

3. The electrochemical device for degrading sulfur hexafluoride waste gas according to claim 2, characterized in that: The electrochemical device for degrading sulfur hexafluoride waste gas also includes a second three-way valve, a fourth pipeline, a fifth pipeline and a sixth pipeline. The fourth pipeline is respectively connected to the washing column corresponding to the anode area and the inlet of the second three-way valve, the fifth pipeline is connected to one of the outlets of the second three-way valve and the anode area, and the sixth pipeline is respectively connected to the other outlet of the second three-way valve and the outside.

4. The electrochemical device for degrading sulfur hexafluoride waste gas according to claim 3, characterized in that: The electrochemical device for degrading sulfur hexafluoride waste gas also includes a third three-way valve, which is arranged in the spray assembly corresponding to the anode area, so that the spray assembly can selectively transport electrolyte to one of the washing column and the outside world.

5. The electrochemical device for degrading sulfur hexafluoride waste gas according to claim 3, characterized in that: The washing column is filled with polytetrafluoroethylene filler; and / or, The second pipeline, the third pipeline and the fifth pipeline are all provided with a check valve.

6. The electrochemical device for degrading sulfur hexafluoride waste gas according to claim 1, characterized in that: The electrochemical device for degrading sulfur hexafluoride waste gas also includes a gas supply unit, which includes a first gas cylinder, a second gas cylinder and a gas mixing component. The first gas cylinder is connected to the gas mixing component through a pipeline, and the first gas cylinder is used to store sulfur hexafluoride. The second gas cylinder is connected to the gas mixing component through a pipeline, and the second gas cylinder is used to store a carrier gas. The gas mixing component is connected to the cathode area through a pipeline, and the gas mixing component is used to evenly mix sulfur hexafluoride and the carrier gas.

7. The electrochemical device for degrading sulfur hexafluoride waste gas according to claim 6, characterized in that: The gas mixing component includes a warm water bath and a gas mixing buffer box, the warm water bath is filled with warm water, the gas mixing buffer box is immersed in the warm water, the first gas cylinder and the second gas cylinder are connected to the inlet of the gas mixing buffer box, and the outlet of the gas mixing buffer box is connected to the cathode area.

8. The electrochemical device for degrading sulfur hexafluoride waste gas according to claim 7, characterized in that: A flow channel for gas to pass through is arranged in the gas mixing buffer box, and the flow channel is arranged in a winding manner.

9. The electrochemical device for degrading sulfur hexafluoride waste gas according to claim 7, characterized in that: The pipelines connecting the first gas cylinder and the second gas cylinder to the gas mixing buffer box are both provided with a pressure reducing valve, a flow meter and a solenoid valve, and the pipeline connecting the gas mixing buffer box to the cathode area is provided with a flow meter and a check valve.

10. The electrochemical device for degrading sulfur hexafluoride waste gas according to claim 1, characterized in that: The spray assembly comprises a spray head and an electromagnetic pump. The spray head is located at the top of the washing column, and the electromagnetic pump is connected to the spray head and the cathode area respectively.

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