Device for using a liquid electrode dielectric barrier discharge reactor for SF 6 decomposition

Abstract

Disclosed in the present invention is a device for using a liquid electrode dielectric barrier discharge reactor for SF6 decomposition, comprising: a gas source, which is communicated with a mixing chamber; and a reactor mechanism, which in communication with a gas outlet end of the mixing chamber. The gas source delivers SF6 and a dilution gas to the mixing chamber in proportion, and the reactor mechanism can decompose gases. By means of accurate gas dilution, the present invention controls the dilution ratio of SF6 in real time. The decomposition efficiency of SF6 can be optimized by means of the mixing chamber. The reactor mechanism can improve the discharge effect of a reaction system, and reduce heat losses caused by heating of ordinary metal electrodes during reactions so as to achieve efficient decomposition of SF6, improving the decomposition efficiency of SF6 exhaust gases and more deeply treating products produced by SF6 decomposition.

Description

A device for degrading SF6 using a liquid electrode dielectric barrier discharge reactor. Technical Field

[0001] This invention relates to the technical field of SF6 treatment, and more particularly to an apparatus for degrading SF6 using a liquid electrode dielectric barrier discharge reactor. Background Technology

[0002] Sulfur hexafluoride (SF6) is a colorless, odorless, non-toxic, non-flammable, and non-explosive inert gas. With a very stable molecular structure, SF6 is widely used in industries such as power equipment, metal smelting, semiconductor manufacturing, and aerospace due to its excellent physicochemical properties. The electrical sector accounts for 80% of SF6 usage annually. However, SF6 has a strong ability to absorb infrared radiation and is a potent greenhouse gas, with a global warming potential (GWP) 23,900 times that of CO2. In the past five years, the atmospheric concentration of SF6 has increased by 20%, and scientists estimate that it will increase by 75% by 2030. To address the increasingly severe problem of climate change, the Paris Agreement has set stricter emission reduction targets. Therefore, SF6 emission reduction is imperative. However, with rapid economic development, the demand for SF6 will only increase further, and humanity faces an increasingly severe problem of SF6 management. In recent years, although the country has proposed carbon neutrality and carbon peaking goals, and replacing SF6 with environmentally friendly gases is an inevitable trend, its effectiveness in the power sector is not as good as SF6, and the amount of SF6 used in the current power system remains enormous. Currently, the world uses more than 10,000 tons of SF6 gas annually, with over 80% used in gas-insulated equipment in the power industry. Damage, leakage, and maintenance of gas-insulated equipment all involve the handling of SF6 gas. Therefore, how to recover and discharge SF6 waste gas has become a hot issue in the field of power environmental protection.

[0003] In recent years, methods for degrading SF6 gas have mainly included thermocatalytic degradation, photolysis, electrolysis, and low-temperature plasma methods. Among these, low-temperature plasma treatment technology has less stringent requirements for reaction conditions compared to other methods, and has advantages such as convenience, simplicity, low energy consumption, and more thorough treatment, making it a promising technology for application. Furthermore, related technologies have already been reported to be used in the treatment of SF6 waste gas.

[0004] Current methods for treating sulfur hexafluoride (SF6) gas mainly focus on its collection, purification, and storage, with external treatments including thermal decomposition and water washing. For SF6 discharge treatment, the mainstream method involves using dielectric barrier discharge (DBD) or microwave discharge to create a plasma region in a designated reactor for SF6 decomposition. In their 2017 study, "Experimental and Simulation Research on Dielectric Barrier Discharge Plasma Degradation of SF6," published in the *Proceedings of the Chinese Society for Electrical Engineering*, Zhang Xiaoxing et al. from Wuhan University used a quartz glass reactor to achieve DBD discharge treatment of SF6 waste gas. During this process, SF6 needs to be diluted, commonly using nitrogen or air as dilution gases, ultimately achieving a degradation rate exceeding 90%. However, in actual degradation, excessively high SF6 concentrations can inhibit the discharge process and weaken the treatment effect; therefore, dilution gases such as nitrogen, argon, or air are needed to dilute the SF6 into a low-concentration mixture. Furthermore, the degradation of SF6 produces toxic gases such as SF4 and SO2. Summary of the Invention

[0005] In view of the problems existing in the above-mentioned liquid electrode dielectric barrier discharge reactor for degrading SF6, the present invention is proposed.

[0006] Therefore, the object of the present invention is to provide an apparatus for degrading SF6 using a liquid electrode dielectric barrier discharge reactor.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including,

[0008] A gas source, which is connected to a mixing chamber;

[0009] The reactor mechanism is connected to the gas outlet of the mixing chamber;

[0010] The gas source delivers SF6 and dilution gas to the mixing chamber in a specific ratio, and the reactor mechanism is capable of degrading the gas.

[0011] As a preferred embodiment of the apparatus for degrading SF6 using the liquid electrode dielectric barrier discharge reactor described in this invention, the gas source includes a first gas cylinder and a second gas cylinder, both of which are connected to the gas inlet of the mixing chamber.

[0012] As a preferred embodiment of the apparatus for degrading SF6 using the liquid electrode dielectric barrier discharge reactor of the present invention, the reactor structure includes a shell, a high-voltage electrode disposed inside the shell, and a low-voltage electrode sleeved on the outside of the high-voltage electrode.

[0013] A plasma discharge region is formed between the high-voltage electrode and the low-voltage electrode, and the gas passing through the mixing chamber enters the plasma discharge region.

[0014] As a preferred embodiment of the apparatus for degrading SF6 using the liquid electrode dielectric barrier discharge reactor of the present invention, wherein: the shell is provided with an inner shell and an outer shell sleeved on the outside of the inner shell, and the plasma discharge zone is located between the inner shell and the outer shell.

[0015] As a preferred embodiment of the apparatus for degrading SF6 in the liquid electrode dielectric barrier discharge reactor of the present invention, the inner shell is disposed outside the high voltage electrode.

[0016] As a preferred embodiment of the apparatus for degrading SF6 using the liquid electrode dielectric barrier discharge reactor of the present invention, wherein: the outer shell has a cavity structure inside, and the low-pressure electrode is disposed in the cavity structure.

[0017] As a preferred embodiment of the apparatus for degrading SF6 using the liquid electrode dielectric barrier discharge reactor of the present invention, the reactor structure is connected to a gas scrubbing tank.

[0018] As a preferred embodiment of the apparatus for degrading SF6 using the liquid electrode dielectric barrier discharge reactor described in this invention, the gas washing tank is provided with a calcium hydroxide solution.

[0019] In a preferred embodiment of the apparatus for degrading SF6 using the liquid electrode dielectric barrier discharge reactor described in this invention, the gas source, mixing chamber, and reactor mechanism are all connected by Teflon gas pipes.

[0020] As a preferred embodiment of the apparatus for degrading SF6 in the liquid electrode dielectric barrier discharge reactor of the present invention, wherein: the inner wall of the mixing chamber is provided with a Teflon coating.

[0021] The beneficial effects of this invention are as follows: by achieving precise gas dilution, the dilution ratio of SF6 can be controlled in real time; the degradation efficiency of SF6 can be optimized through the mixing chamber; the reactor structure can improve the discharge effect of the reaction system and reduce the heat loss caused by the heating of ordinary metal electrodes during the reaction, thereby achieving efficient degradation of SF6; thus improving the degradation efficiency of SF6 waste gas and enabling deeper treatment of the products after SF6 degradation. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0023] Figure 1 is a schematic diagram of the overall structure of the device of the present invention.

[0024] Figure 2 is a schematic diagram of the reaction chamber mechanism in this invention. Detailed Implementation

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0026] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0027] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0028] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0029] Example 1

[0030] Referring to Figures 1-2, an apparatus for degrading SF6 using a liquid electrode dielectric barrier discharge reactor is provided, comprising:

[0031] Gas source 100, which is connected to mixing chamber 200;

[0032] The reactor mechanism 300 is connected to the gas outlet of the mixing chamber 200;

[0033] Among them, the gas source 100 delivers SF6 and dilution gas to the mixing chamber 200 in proportion, and the reactor mechanism 300 can degrade SF6 gas.

[0034] The gas source 100 is connected to the mixing chamber 200 via a gas path. The other end of the mixing chamber 200 is connected to the reactor mechanism 300 via a gas path. The mixing chamber 200 is a cylinder consisting of an upper gas chamber and a lower fan. The fan is installed at the bottom. SF6 and dilution gas from the gas source 100 enter the mixing chamber 200. The fan at the bottom mixes the diluted SF6 gas mixture, which can thoroughly agitate the gas entering the mixing chamber 200. Through the action of the mixing chamber 200, the gases are evenly distributed in the space before entering the reactor mechanism 300 for reaction. After the mixed gas enters the reactor mechanism 300, it can react inside and then be degraded.

[0035] A pressure reducing valve and an electromagnetic flow meter are connected sequentially from the mixing chamber 200 side to the reactor mechanism 300 side. Since the experiment is carried out under closed conditions, the fan in the mixing chamber 200 will change the air pressure and gas flow rate. Therefore, a pressure reducing valve and an electromagnetic flow meter are added to the gas path for control and detection. The electromagnetic flow meter can directly prevent the mixed gas from entering the reaction chamber in an emergency, reducing experimental safety hazards.

[0036] Furthermore, the gas source 100 includes a first gas cylinder 101 and a second gas cylinder 102, both of which are connected to the air inlet of the mixing chamber 200.

[0037] The first gas cylinder 101 contains SF6 gas, and the second gas cylinder 102 contains dilution gas. The first gas cylinder 101 and the second gas cylinder 102 are each provided with two gas paths. The ends of the two gas paths merge into one and are connected to the air inlet of the mixing chamber 200. A pressure reducing valve, an electromagnetic flow meter, and a solenoid valve are connected sequentially from the side of the gas cylinder to the end of the two gas paths. The electromagnetic flow meter can be used to monitor the gas flow rate in real time, and the solenoid valve can control the shut-off of the gas path. The two gases are mixed according to the calculated ratio, so that the ratio of SF6 to dilution gas can be precisely controlled by the pressure reducing valves of the two paths and the electromagnetic flow meter, thereby controlling the dilution ratio of SF6 and achieving precise dilution of SF6.

[0038] In this embodiment, the diluent gas is preferably argon, nitrogen, or air, and any one of the three can be selected.

[0039] Furthermore, the reactor mechanism 300 includes a housing 301, a high-voltage electrode 302 disposed inside the housing 301, and a low-voltage electrode 303 sleeved on the outside of the high-voltage electrode 302.

[0040] Among them, a plasma discharge region 304 is formed between the high-voltage electrode 302 and the low-voltage electrode 303, and the gas passing through the mixing chamber 200 enters the plasma discharge region 304.

[0041] In this embodiment, the low-pressure electrode 303 is preferably a liquid electrode; the liquid electrode medium can improve the discharge effect of the reaction system, while reducing the heat loss caused by the heating of ordinary metal electrodes during the reaction, thereby achieving efficient degradation of SF6.

[0042] The diluted and mixed gas enters the housing 301, and the airflow causes the mixed gas to enter the plasma discharge zone 304, where it is degraded, thereby achieving the degradation of SF6.

[0043] Furthermore, the gas source 100, mixing chamber 200, and reactor mechanism 300 are all connected by Teflon gas pipes; this reduces corrosion of the pipe materials and extends the service life of the equipment.

[0044] Furthermore, the inner wall of the mixing chamber 200 is coated with Teflon; by using the Teflon coating, corrosion of the mixing chamber 200 by the gas is prevented.

[0045] Operating procedure: When in use, first open the main valve of the gas cylinder. The gas in the first gas cylinder 101 and the second gas cylinder 102 is first discharged after being depressurized by the pressure reducing valve, and then passes through the electromagnetic flow meter and electromagnetic valve. Then, adjust all the pressure reducing valves to about 0.2 MPa. Next, open the electromagnetic valve between the gas cylinder and the gas mixing chamber 200, and set the flow rate of all electromagnetic flow meters so that the mixing flow rate of the gas path is the set value. Finally, open the electromagnetic valve between the mixing chamber 200 and the reactor mechanism 300. After the gas merges in the gas pipe, it enters the gas mixing chamber 200. After being mixed in the mixing chamber 200, it enters the reactor mechanism 300. In the reactor mechanism, the SF6 waste gas is treated.

[0046] By achieving precise gas dilution, the dilution ratio of SF6 can be controlled in real time; the SF6 degradation efficiency can be optimized through the mixing chamber 200; the reactor structure 300 can improve the discharge effect of the reaction system and reduce the heat loss caused by the heating of ordinary metal electrodes during the reaction process, thereby achieving efficient degradation of SF6; thus improving the degradation efficiency of SF6 waste gas and enabling deeper treatment of the products after SF6 degradation.

[0047] Example 2

[0048] Referring to Figures 1-2, this embodiment differs from the first embodiment in that: the housing 301 is provided with an inner shell 301a inside, and an outer shell 301b sleeved on the outside of the inner shell 301a, and the plasma discharge region 304 is disposed between the inner shell 301a and the outer shell 301b.

[0049] The inner shell 301a is located outside the high voltage electrode 302; the outer shell 301b has a cavity structure inside, and the low voltage electrode 303 is located in the cavity structure.

[0050] The high-voltage electrode 302 penetrates both ends of the housing 301. The inner shell 301a and the outer shell 301b are both located inside the housing 301. The high-voltage electrode 302 is a hollow cylinder made of stainless steel, and the low-voltage electrode 303 is a liquid solution. The inner shell 301a and the outer shell 301b are each composed of two coaxial cylindrical glass, while the outer shell 301b has a cavity structure. The low-voltage electrode 303 is located in the outer shell 301b. The high-voltage electrode 302 is placed in the middle, and the inner shell 301a is close to the outside of the high-voltage electrode 302. The gap between the inner wall of the outer shell 301b and the outer wall of the inner shell 301a is 4mm.

[0051] The inner shell is provided with a liquid inlet and a liquid outlet to facilitate the adjustment of the liquid electrode inside.

[0052] Using liquid electrode medium as the reactor structure 300 can improve the discharge effect of the reaction system and reduce the heat loss caused by the heating of ordinary metal electrodes during the reaction process, thereby achieving efficient degradation of SF6.

[0053] In this embodiment, the liquid electrode is a conductive solution, such as water or NaCl solution, and the conductive solution is grounded through a conductive medium.

[0054] The rest of the structure is the same as in Example 1.

[0055] Example 3

[0056] Referring to Figures 1-2, this embodiment differs from the above embodiments in that: the reactor mechanism 300 is connected to a gas scrubbing tank 400; the gas scrubbing tank 400 contains a calcium hydroxide solution;

[0057] The reactor and the gas scrubbing tank 400 are directly connected by gas pipes, all of which are made of Teflon for corrosion protection. The inner wall of the gas scrubbing tank 400 should be coated with Teflon to prevent corrosion and adsorption.

[0058] After degradation treatment in reactor 300, the mixed gas enters scrubbing tank 400, which is filled with saturated calcium hydroxide solution. Each scrubbing tank 400 contains a fine mesh screen, which breaks the bubbles entering the scrubbing tank 400 into several smaller bubbles, increasing the contact area with the alkaline solution and more effectively treating the toxic gases after degradation. This facilitates the absorption of toxic gases from the degraded gas by the calcium hydroxide solution. Finally, the discharged gas is centrally treated, thus optimizing the efficiency of SF6 degradation and tail gas treatment. Through scrubbing tank 400, most of the toxic gases produced by decomposition can be absorbed, further reducing the toxic gases in the tail gas.

[0059] The rest of the structure is the same as in Example 2.

[0060] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., changes in the size, dimensions, structure, shape, and proportions of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application). For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of elements may be inverted or otherwise altered, and the nature or number or position of discrete elements may be changed or altered. Therefore, all such modifications are intended to be included within the scope of the invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the present invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0061] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments (i.e., those features that are not relevant to the best mode of carrying out the invention as currently considered, or those features that are not relevant to implementing the invention) may be omitted.

[0062] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0063] It should be noted that 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A device for degrading SF6 using a liquid electrode dielectric barrier discharge reactor, characterized in that: include, A gas source (100) is connected to a mixing chamber (200); The reactor mechanism (300) is connected to the gas outlet of the mixing chamber (200); The gas source (100) delivers SF6 and dilution gas to the mixing chamber (200) in a proportional manner, and the reactor mechanism (300) is capable of degrading SF6 gas.

2. The apparatus for degrading SF6 using a liquid electrode dielectric barrier discharge reactor as described in claim 1, characterized in that: The gas source (100) includes a first gas cylinder (101) and a second gas cylinder (102), both of which are connected to the air inlet of the mixing chamber (200).

3. The apparatus for degrading SF6 using a liquid electrode dielectric barrier discharge reactor as described in claim 2, characterized in that: The reactor mechanism (300) includes a housing (301), a high-voltage electrode (302) disposed inside the housing (301), and a low-voltage electrode (303) sleeved on the outside of the high-voltage electrode (302); A plasma discharge region (304) is formed between the high-voltage electrode (302) and the low-voltage electrode (303), and the gas passing through the mixing chamber (200) enters the plasma discharge region (304).

4. The apparatus for degrading SF6 using a liquid electrode dielectric barrier discharge reactor as described in claim 3, characterized in that: The housing (301) has an inner shell (301a) inside and an outer shell (301b) sleeved on the outside of the inner shell (301a). The plasma discharge region (304) is located between the inner shell (301a) and the outer shell (301b).

5. The apparatus for degrading SF6 using a liquid electrode dielectric barrier discharge reactor as described in claim 4, characterized in that: The inner shell (301a) is located outside the high voltage electrode (302).

6. The apparatus for degrading SF6 using a liquid electrode dielectric barrier discharge reactor as described in claim 5, characterized in that: The outer shell (301b) has a cavity structure inside, and the low-pressure electrode (303) is disposed in the cavity structure.

7. The apparatus for degrading SF6 using a liquid electrode dielectric barrier discharge reactor as described in claim 5 or 6, characterized in that: The reactor structure (300) is connected to a gas scrubbing tank (400).

8. The apparatus for degrading SF6 using a liquid electrode dielectric barrier discharge reactor as described in claim 7, characterized in that: The air scrubbing tank (400) contains a calcium hydroxide solution.

9. The apparatus for degrading SF6 using a liquid electrode dielectric barrier discharge reactor as described in claim 8, characterized in that: The gas source (100), mixing chamber (200), and reactor mechanism (300) are all connected by Teflon gas pipes.

10. The apparatus for degrading SF6 using a liquid electrode dielectric barrier discharge reactor as described in claim 8 or 9, characterized in that: The inner wall of the mixing chamber (200) is coated with Teflon.

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