Device for degrading SF6 (sulfur hexafluoride) by liquid electrode dielectric barrier discharge reactor

Abstract

The invention discloses a device for degrading SF6 (sulfur hexafluoride) by a liquid electrode dielectric barrier discharge reactor, which comprises a gas source communicated with a uniform mixing chamber; the reactor mechanism is communicated with the gas outlet end of the uniform mixing chamber; wherein the gas source is used for conveying SF6 and diluent gas into the uniform mixing chamber in proportion, and the reactor mechanism can be used for degrading the gas; according to the invention, accurate gas dilution is realized, and the dilution ratio of SF6 is controlled in real time; the degradation efficiency of SF6 can be optimized through the uniform mixing chamber; the reactor mechanism can improve the discharge effect of a reaction system, meanwhile, heat loss caused by heating of a common metal electrode in the reaction process is reduced, and efficient degradation of SF6 is achieved; the degradation efficiency of the SF6 waste gas is improved, and deeper-degree treatment on products obtained after SF6 degradation is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of SF6 treatment, and in particular to a device for degrading SF6 using a liquid electrode dielectric barrier discharge reactor. Background Art

[0002] Sulfur hexafluoride (SF6) is a colorless, odorless, non-toxic, non-flammable and non-explosive inert gas. With a very stable molecular structure and excellent physical and chemical properties, SF6 is widely used in power equipment, metal smelting, semiconductor manufacturing and aerospace industries, among which the use of SF6 in the electrical field accounts for 80% of the total annual use of SF6. However, SF6 has a strong ability to absorb infrared radiation and is a strong greenhouse gas with a greenhouse effect potential (GWP) as high as 23,900 times that of CO2. In the past five years, the content of SF6 in the atmosphere has risen by 20%, and scientists estimate that its atmospheric content will increase by 75% by 2030. In order to cope with the increasingly severe problem of climate change, the Paris Agreement has proposed stricter emission reduction targets. Therefore, SF6 emission reduction is imperative. However, with the rapid development of the economy, human society's demand for SF6 will only be greater than before, and humans are facing increasingly severe SF6 governance issues. In recent years, it is a general trend to replace SF6 with environmentally friendly gas, but in the field of power, its effect is not as good as SF6, and in today's power system, the use of SF6 is still huge. At present, more than 10,000 tons of SF6 gas are used in the world every year, of which more than 80% are used in gas-insulated equipment in the power industry. The damage, leakage and maintenance of gas-insulated equipment will face the problem of SF6 gas treatment. Therefore, how to recycle and discharge SF6 waste gas has become a hot issue in the field of power environmental protection.

[0003] In recent years, the means of degrading SF6 gas mainly include thermal catalytic degradation, photolysis, electrolysis, low-temperature plasma method, etc. Among them, low-temperature plasma treatment technology is not as demanding on reaction conditions as other methods, and has the advantages of convenience, simplicity, low energy consumption, and more thorough treatment. It has a very broad application prospect, and related technologies have also been reported to be applied in the treatment of SF6 waste gas.

[0004] At present, the methods for treating sulfur hexafluoride gas mainly focus on collecting, purifying and storing sulfur hexafluoride gas, and thermal cracking and water washing are used to treat SF6 waste gas. For the discharge treatment process of SF6, the mainstream method is to use dielectric barrier discharge, microwave discharge and other forms to form a plasma area in a designated reactor to decompose and treat SF6 gas. In the "Experimental and Simulation Study on Dielectric Barrier Discharge Plasma Degradation of SF6" published in the "Proceedings of the CSEE" by Zhang Xiaoxing and others from Wuhan University in 2017, a quartz glass reactor was used to achieve DBD discharge treatment of SF6 waste gas. During the treatment process, SF6 needs to be diluted, and the dilution gas is usually nitrogen, air, etc., which can eventually achieve a degradation effect of more than 90%. However, in the actual degradation process, since the excessive SF6 concentration will inhibit the discharge process and weaken the treatment effect, some dilution gases such as nitrogen, argon or air are needed to dilute SF6 into a low-concentration mixed gas. And after the degradation of SF6, toxic gases such as SF4 and SO2 will be produced. Summary of the invention

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

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

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

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

[0009] A reactor mechanism, which is connected to the gas outlet end of the mixing chamber;

[0010] The gas source delivers SF6 and dilution gas to the mixing chamber in proportion, and the reactor mechanism can perform gas degradation treatment.

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

[0012] As a preferred solution of the device for degrading SF6 in the liquid electrode dielectric barrier discharge reactor of the present invention, the reactor mechanism includes a shell, a high-voltage electrode arranged inside the shell, and a low-voltage electrode sleeved on the outside of the high-voltage electrode;

[0013] Wherein, a plasma discharge zone is formed between the high voltage electrode and the low voltage electrode, and the gas passing through the mixing chamber enters the plasma discharge zone.

[0014] As a preferred solution of the device for degrading SF6 in the liquid electrode dielectric barrier discharge reactor of the present invention, an inner shell and an outer shell sleeved on the outer side of the inner shell are provided inside the shell, and the plasma discharge zone is provided between the inner shell and the outer shell.

[0015] As a preferred solution of the device for degrading SF6 in the liquid electrode dielectric barrier discharge reactor of the present invention, the inner shell is arranged on the outside of the high-voltage electrode.

[0016] As a preferred solution of the device for degrading SF6 in the liquid electrode dielectric barrier discharge reactor of the present invention, the interior of the outer shell has a cavity structure, and the low-voltage electrode is arranged in the cavity structure.

[0017] As a preferred solution of the device for degrading SF6 in the liquid electrode dielectric barrier discharge reactor of the present invention, the reactor mechanism is connected to a gas washing tank.

[0018] As a preferred solution of the device for degrading SF6 in the liquid electrode dielectric barrier discharge reactor of the present invention, a calcium hydroxide solution is provided in the gas washing tank.

[0019] As a preferred solution of the device for degrading SF6 in the liquid electrode dielectric barrier discharge reactor of the present invention, the gas source, the mixing chamber and the reactor mechanism are all connected by a Teflon gas pipe.

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

[0021] The beneficial effects of the present 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 mechanism 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 process, thereby achieving efficient degradation of SF6; thereby improving the degradation efficiency of SF6 waste gas and achieving a deeper degree of treatment of the products after SF6 degradation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

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

[0024] Figure 2 It is a structural schematic diagram of the reaction chamber mechanism in the present invention. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0026] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present 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 term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0028] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0029] Example 1

[0030] Reference Figure 1-Figure 2 , provides a device for degrading SF6 using a liquid electrode dielectric barrier discharge reactor, comprising:

[0031] A gas source 100, which is connected to a mixing chamber 200;

[0032] A reactor mechanism 300, which is connected to the gas outlet end of the mixing chamber 200;

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

[0034] The gas source 100 is connected to the mixing chamber 200 through an air path, and the other end of the mixing chamber 200 is connected to the reactor mechanism 300 through an air path. The mixing chamber 200 is a cylinder, which is composed of an upper air chamber and a lower fan. A fan is installed at the bottom. The SF6 in the gas source 100 and the dilution gas enter the mixing chamber 200. The fan at the bottom mixes the diluted SF6 mixed gas, which can fully stir the gas entering the mixing chamber 200. Through the action of the mixing chamber 200, each gas is evenly distributed in the space, and then enters the reactor mechanism 300 for reaction; after the mixed gas enters the reactor mechanism 300, it can react inside it and then be degraded;

[0035] A pressure reducing valve and an electromagnetic flowmeter are connected in sequence 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 flowmeter are added to the gas circuit for control and detection. The electromagnetic flowmeter can directly prevent the mixed gas from entering the reaction chamber in an emergency, thereby reducing safety hazards in the experiment.

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

[0037] The first gas cylinder 101 is loaded with SF6 gas, and the second gas cylinder 102 is loaded with dilution gas. The first gas cylinder 101 and the second gas cylinder 102 are respectively provided with two gas paths, and the ends of the two gas paths merge into one path connected to the gas inlet of the mixing chamber 200, and the two gas paths are sequentially connected with a pressure reducing valve, an electromagnetic flowmeter and an electromagnetic valve from the lateral ends of the gas cylinders. The electromagnetic flowmeter can be used to monitor the flow rate of the gas in real time, and the electromagnetic valve can control the shutoff of the gas path. The two gases are mixed according to the calculated ratio, so that the ratio of SF6 and the dilution gas can be accurately controlled by the pressure reducing valves and the electromagnetic flowmeters of the two paths, and then the dilution ratio of SF6 can be controlled, thereby realizing accurate dilution of SF6;

[0038] In this embodiment, the dilution gas is preferably argon, nitrogen and air, 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] 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 voltage 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 process, 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 the mixed gas is degraded, thereby achieving the degradation of SF6.

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

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

[0045] Operation process: 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 through the pressure reduction of the pressure reducing valve, then passes through the electromagnetic flowmeter and the electromagnetic valve, and then all the pressure reducing valves are adjusted to about 0.2Mpa, and then the electromagnetic valve between the gas cylinder and the gas mixing chamber 200 is opened, and the flow of all electromagnetic flowmeters is set so that the mixed flow of the gas path is the set value, and finally the electromagnetic valve between the mixing chamber 200 and the reactor mechanism 300 is opened, and the gas enters the gas mixing chamber 200 after merging in the air pipe, and enters the reactor mechanism 300 after being mixed in the mixing chamber 200, and the SF6 waste gas is treated in the reactor mechanism;

[0046] 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 200; the reactor mechanism 300 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 process, thereby achieving efficient degradation of SF6; thereby improving the degradation efficiency of SF6 waste gas and achieving a deeper level of treatment of the products after SF6 degradation.

[0047] Example 2

[0048] Reference Figure 1-Figure 2 , this embodiment is different from the first embodiment in that: an inner shell 301a is provided inside the housing 301, and an outer shell 301b is sleeved on the outer side of the inner shell 301a, and a plasma discharge zone 304 is provided between the inner shell 301a and the outer shell 301b;

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

[0050] Both ends of the high-voltage electrode 302 pass through both ends of the shell 301, and the inner shell 301a and the outer shell 301b are both located inside the shell 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 respectively composed of two coaxial cylindrical glasses, and the outer shell 301b has a cavity structure, and the low-voltage electrode 303 is located in the outer shell 301b; the high-voltage electrode 302 is placed in the middle, the inner shell 301a is close to the outside of the high-voltage electrode 302, and 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 it;

[0052] Using liquid electrode medium as the reactor mechanism 300 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 process, thereby achieving efficient degradation of SF6.

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

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

[0055] Example 3

[0056] Reference Figure 1-Figure 2 , this embodiment is different from the above embodiments in that: the reactor mechanism 300 is connected to a gas washing pool 400; the gas washing pool 400 is provided with a calcium hydroxide solution;

[0057] The reactor is directly connected to the gas washing pool 400 through an air pipe, and the air pipe is made of Teflon material to prevent corrosion; the inner wall of the gas washing pool 400 should be coated with Teflon to prevent corrosion and adsorption;

[0058] The mixed gas after degradation treatment in the reactor mechanism 300 enters the scrubbing pool 400, which contains a saturated calcium hydroxide solution, and each scrubbing pool 400 has a fine mesh, which can divide the bubbles entering the scrubbing pool 400 into a number of small bubbles, thereby increasing the contact area with the alkaline solution, and more effectively treating the degraded toxic gas, which is beneficial for the calcium hydroxide solution to absorb the toxic gas in the degraded gas, and finally the exhausted gas is treated in a unified and centralized manner, thereby optimizing the efficiency of SF6 degradation and exhaust gas treatment; through the scrubbing pool 400, most of the toxic gases produced by decomposition can be absorbed, so that the toxic gases in the exhaust gas are further reduced.

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

[0060] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered 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 is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to numerous modifications still falling within the scope of the appended claims.

[0061] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0062] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0063] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in 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) connected to a mixing chamber (200); A reactor mechanism (300) is communicated with the gas outlet end of the mixing chamber (200); The gas source (100) delivers SF6 and dilution gas to the mixing chamber (200) in proportion, and the reactor mechanism (300) is capable of degrading the SF6 gas.

2. The device for degrading SF6 by a liquid electrode dielectric barrier discharge reactor according to claim 1, characterized in that: The gas source (100) comprises a first gas cylinder (101) and a second gas cylinder (102), and the first gas cylinder (101) and the second gas cylinder (102) are both connected to the gas inlet end of the mixing chamber (200).

3. The device for degrading SF6 by a liquid electrode dielectric barrier discharge reactor as claimed in claim 2, characterized in that: The reactor mechanism (300) comprises a shell (301), a high-voltage electrode (302) disposed inside the shell (301), and a low-voltage electrode (303) sleeved on the outside of the high-voltage electrode (302); A plasma discharge zone (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 zone (304).

4. The device for degrading SF6 by a liquid electrode dielectric barrier discharge reactor as claimed in claim 3, characterized in that: The shell (301) is provided with an inner shell (301a) and an outer shell (301b) sleeved on the outer side of the inner shell (301a), and the plasma discharge zone (304) is provided between the inner shell (301a) and the outer shell (301b).

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

6. The device for degrading SF6 by a liquid electrode dielectric barrier discharge reactor as claimed in claim 5, characterized in that: The outer shell (301b) has a cavity structure inside, and the low-voltage electrode (303) is arranged in the cavity structure.

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

8. The device for degrading SF6 by a liquid electrode dielectric barrier discharge reactor as claimed in claim 7, characterized in that: A calcium hydroxide solution is provided in the gas washing pool (400).

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

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

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