Method and system for degrading SF 6 based on placement of copper rings on inner electrodes of dbd

Abstract

Provided are a method and system for degrading SF6 based on the placement of copper rings (201) on inner electrodes of DBD. The method comprises: delivering precisely proportioned and diluted SF6 into a DBD reactor (200), electrode rods in the DBD reactor (200) discharging to form an electric field, and a plurality of copper rings (201) on the electrode rods being used to alter local discharge gaps and the electric field to achieve degradation of SF6; introducing the diluted SF6 into a plasma environment, SF6 molecules being bombarded by high-energy electrons and ionized and excited molecules to undergo a cleavage reaction to generate low-toxicity or non-toxic decomposition products. The resulting decomposition products are easier to adsorb and treat compared to SF6, reducing the amount of diluent gas required, lowering cost waste, and effectively improving the degradation efficiency of SF6.

Description

A method and system for degrading SF6 based on copper rings placed in the internal electrode of a DBD (Diverterless Degradation Device). Technical Field

[0001] This invention relates to the technical field of SF6 treatment, and in particular to a method and system for degrading SF6 based on placing a copper ring on the internal electrode of a DBD (Diverterless Degradation Device). Background Technology

[0002] SF6 is a synthetic gas in which the central sulfur atom is stably connected to the six surrounding fluorine atoms by covalent bonds, forming an octahedral configuration. SF6 gas itself is colorless, odorless, non-toxic, non-flammable, and slightly soluble in water. It is chemically very stable, has strong electron affinity, and can undergo a self-restoration process after bond breakage, thus possessing excellent insulation and arc-quenching properties.

[0003] SF6 is widely used in the power industry as an excellent gaseous insulating material, and is also used as a protective gas in semiconductor processing and ore smelting. Although SF6 has many excellent properties, its high efficiency absorption of infrared radiation in the 915-960 cm-1 band leads to a serious greenhouse effect. It is listed as one of the six limiting gases in the Kyoto Protocol. Its greenhouse potential is 23,500 times that of CO2, far exceeding other greenhouse gases. SF6 can exist stably in the atmosphere for up to 3,200 years and only decomposes slowly under ultraviolet light.

[0004] Therefore, the large-scale emission of SF6 waste gas poses a serious threat to the atmospheric environment. For the discharge treatment process of SF6, the mainstream method is to use dielectric barrier discharge, thermal plasma discharge, microwave discharge, etc., to form a plasma region in a designated reactor to decompose SF6 gas. In the "Experimental and Simulation Study on Dielectric Barrier Discharge Plasma Degradation of SF6" published in the Proceedings of the Chinese Society for Electrical Engineering in 2017, Zhang Xiaoxing et al. of Wuhan University used a quartz glass reactor to achieve DBD discharge treatment of SF6 waste gas. During the treatment process, SF6 needs to be diluted. Nitrogen and air are commonly used as dilution gases. Finally, a degradation effect of more than 90% can be achieved.

[0005] However, in this method, SF6 gas is degraded under static conditions, and the products are mainly acidic and toxic gases, which limits the emission. Other scholars who have studied the electrolysis process of SF6 waste gas also need to dilute the SF6 gas. Excessively high concentrations of SF6 gas will inhibit the discharge process and weaken the treatment effect. As a result, a large amount of gas needs to be consumed in the dilution process, leading to gas waste. This problem needs to be solved. Summary of the Invention

[0006] In view of the problems existing in the above-mentioned methods and systems for degrading SF6 based on placing copper rings in the internal electrode of DBD, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to provide a method and system for degrading SF6 based on placing a copper ring on the internal electrode of a DBD.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for degrading SF6 based on copper rings placed on the internal electrodes of a DBD reactor, comprising: transporting precisely diluted SF6 to a DBD reactor; generating an electric field by discharging electrode rods in the DBD reactor; and using several copper rings on the electrode rods to change the partial discharge gap and electric field to complete the degradation of SF6.

[0009] As a preferred embodiment of the method for degrading SF6 based on the DBD inner electrode with copper rings according to the present invention, the inner diameter of the copper ring is consistent with the outer diameter of the electrode rod, the thickness of the copper ring is 1.6 mm, and the gap between two adjacent copper rings is 25 mm.

[0010] As a preferred embodiment of the method for degrading SF6 based on placing a copper ring in the internal electrode of the DBD according to the present invention, the gas used to dilute SF6 is Ar, and the amount used is: 98% Ar diluting 2% SF6.

[0011] As a preferred embodiment of the method for degrading SF6 based on copper rings placed in the DBD internal electrode according to the present invention, the electrode rod in the DBD reactor is powered by a plasma power supply, which is an AC power supply with an AC voltage of 2-4kW at 10kHz.

[0012] In a preferred embodiment of the method for degrading SF6 based on placing a copper ring with an internal electrode in DBD according to the present invention, both ends of the electrode rod are equipped with grounding wires.

[0013] A system for degrading SF6 based on placing a copper ring with an internal electrode in a DBD (Diverterless Degradation Device), applied to the aforementioned method for degrading SF6 based on placing a copper ring with an internal electrode in a DBD, comprising:

[0014] The gas supply section is used to prepare a mixture of Ar and SF6 gas at the required concentration.

[0015] The DBD reactor has several copper rings evenly spaced on the electrode rods inside, and is equipped with an air inlet and an air outlet.

[0016] The absorption unit has its air inlet connected to the air outlet.

[0017] As a preferred embodiment of the system for degrading SF6 based on a copper ring placed in a DBD internal electrode according to the present invention, the gas supply section includes:

[0018] The gas storage unit consists of two gas tanks, which are used to store Ar and SF6 gas respectively.

[0019] The gas mixer has an inlet end connected to a gas tank and an outlet end connected to a DBD reactor. It is used to deliver the proportioned Ar and SF6 mixed gas to the DBD reactor.

[0020] As a preferred embodiment of the system for degrading SF6 based on a copper ring placed in a DBD internal electrode according to the present invention, the absorption unit includes:

[0021] A gas detector is used to detect the SF6 concentration in the gas discharged from the DBD reactor;

[0022] Adsorption components are used to degrade and absorb gases emitted from the DBD reactor.

[0023] As a preferred embodiment of the system for degrading SF6 based on copper rings placed in the DBD internal electrode according to the present invention, the adsorption component includes:

[0024] tower body;

[0025] A liquid storage tank is located at the bottom inner part of the tower body;

[0026] The packing layer, located in the middle section of the tower, is used to adsorb and remove harmful gases in the rising gas.

[0027] The spray head is used to spray the treatment liquid in the storage tank from top to bottom, so that it can come into contact with the rising gas and settle.

[0028] As a preferred embodiment of the system for degrading SF6 based on placing a copper ring with an internal electrode in DBD according to the present invention, the treatment solution is any one of water, alkaline solution or acid solution.

[0029] The beneficial effects of the present invention are as follows: The present invention introduces diluted SF6 into a plasma environment, where SF6 molecules are bombarded by high-energy electrons, ionization and excited-state molecules, resulting in a cracking reaction and generating low-toxicity or non-toxic decomposition products. The generated decomposition products are easier to adsorb and treat than SF6, reducing the amount of dilution gas used, reducing cost waste, and effectively improving the degradation efficiency of SF6.

[0030] By placing several copper rings on the inner electrode rod of the DBD reactor, the partial discharge gap and electric field were changed, the local electric field was increased, and the non-uniform discharge gap made the discharge more stable and the intensity more uniform. At the same time, the charge collision probability rate was increased, thus improving the SF6 degradation rate. Attached Figure Description

[0031] 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:

[0032] Figure 1 is an experimental diagram of the copper ring-free system of the method for degrading SF6 based on the internal electrode of DBD according to the present invention.

[0033] Figure 2 is an experimental diagram of the copper ring system in the method of degrading SF6 based on the internal electrode of DBD according to the present invention.

[0034] Figure 3 shows the Lissajous figures of two systems in the method for degrading SF6 based on the internal electrode placement of a copper ring in the DBD according to the present invention.

[0035] Figure 4 is a schematic diagram of the system framework for the degradation of SF6 based on the placement of a copper ring in the DBD internal electrode according to the present invention.

[0036] Figure 5 is a schematic diagram of the gas supply section of the system based on the DBD internal electrode with copper ring for SF6 degradation according to the present invention.

[0037] Figure 6 is a schematic diagram of the system absorption section of the present invention based on the placement of a copper ring in the DBD internal electrode to degrade SF6.

[0038] Figure 7 is a schematic diagram of the adsorption component of the system for degrading SF6 based on the internal electrode of the DBD according to the present invention. Detailed Implementation

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] Example 1

[0044] A method for degrading SF6 based on copper rings placed on the internal electrodes of a DBD reactor includes: delivering precisely diluted SF6 to a DBD reactor 200; generating an electric field by discharging electrode rods in the DBD reactor 200; and using several copper rings 201 on the electrode rods to change the partial discharge gap and electric field to complete the degradation of SF6.

[0045] Furthermore, the inner diameter of the copper ring 201 is consistent with the outer diameter of the electrode rod, and the thickness of the copper ring 201 is 1.6 mm. The gap between two adjacent copper rings 201 is 25 mm. The small discharge gap in the copper ring 201 increases the local electric field. The non-uniform discharge gap makes the discharge more stable and the intensity more uniform. At the same time, it increases the charge collision probability rate and improves the SF6 degradation rate.

[0046] Specific ， The addition of copper ring 201 increases the local electric field, displacement charge, and discharge fraction, making the discharge more stable and the intensity more uniform. It reduces the local discharge gap and changes the electric field, promoting discharge while having little impact on the discharge volume. This can induce discharge on copper ring 201, thereby changing the discharge distribution and making the plasma more uniform, thus improving the plasma discharge performance of DBD reactor 200.

[0047] Furthermore, the gas used to dilute SF6 is Ar, and the dosage is: 98% Ar to dilute 2% SF6. This ratio can ensure the dilution effect of SF6, and the diluted mixed gas will have a better treatment effect in the DBD reactor 200.

[0048] Furthermore, the electrode rods in the DBD reactor 200 are powered by a plasma power supply, which uses an AC power supply with an AC voltage of 2-4kW at 10kHz. The plasma power supply applies a sufficiently high AC voltage between the electrode rods to generate a discharge phenomenon. During the discharge process, a high-frequency, high-voltage AC electric field is formed between the inner and outer electrodes, which excites the dielectric barrier discharge in the DBD reactor 200 to generate plasma. In the plasma environment, SF6 molecules are bombarded by high-energy electrons, ionized and excited-state molecules, resulting in a cracking reaction and generating low-toxicity or non-toxic decomposition products (such as sulfur, fluorides, etc.). The generated decomposition products are easier to adsorb and treat than SF6, reducing the amount of dilution gas used, reducing cost waste, and effectively improving the degradation efficiency of SF6.

[0049] Furthermore, grounding wires are installed at both ends of the electrode rod to comply with electrical regulations and reduce safety hazards.

[0050] Experimental results:

[0051] To investigate the changes in electrical parameters of a system with copper rings placed on the internal electrode rod of the DBD reactor 200, the discharge voltage and current of the system were measured, and the Lissajous figures of the discharge were analyzed, as shown in Figures 1, 2 and 3.

[0052] As can be seen from Figures 1 and 2, both the discharge voltage and current waveforms are sinusoidal, indicating that the discharge system is capacitive.

[0053] In the copper ring-free system, there are more filament discharges caused by uneven discharge. After placing the copper ring, the discharge current waveform is closer to a sine wave due to the change in reactor capacitance. The discharge dielectric capacitance increases from 57.63pF in the empty tube system to 75.54pF, and the discharge current phase is more advanced. However, the discharge current does not increase significantly. The discharge is more uniform after placing the copper ring.

[0054] Figure 3 shows the Lissajous figures of the DBD reactor 200 before and after the copper ring was placed. The area of ​​the Lissajous figures increased significantly after the glass beads were filled, indicating that more energy was used to excite the decomposition reaction of SF6 molecules. In addition, the magnitude of charge transfer also increased, indicating that more energy participated in the reaction in each discharge cycle. This suggests that the addition of the copper ring 201 greatly improves the degradation of SF6.

[0055] Example 2

[0056] Referring to Figures 4-5, this embodiment differs from the first embodiment in that: this embodiment discloses a system for degrading SF6 based on placing a copper ring with an internal electrode in a DBD, applied to the aforementioned method for degrading SF6 based on placing a copper ring with an internal electrode in a DBD, comprising:

[0057] The gas supply section 100 is used to prepare a mixture of Ar and SF6 gas at the required concentration.

[0058] The DBD reactor 200 has several copper rings 201 evenly arranged on the electrode rod inside, and has an air inlet 202 and an air outlet 203.

[0059] The absorption unit 300 has its air inlet end connected to the air outlet 203.

[0060] Furthermore, the gas supply section 100 includes:

[0061] The gas storage unit 101 consists of two gas tanks, which are used to store Ar and SF6 gas respectively.

[0062] The gas mixer 102 has an inlet end connected to a gas tank and an outlet end connected to the DBD reactor 200. It is used to deliver the proportioned Ar and SF6 mixed gas to the DBD reactor 200.

[0063] Specifically, the two gas cylinders are connected to the gas mixing device 102 through two gas lines. Each gas line is equipped with a rotary valve and an electromagnetic flow meter. After the gas cylinder pressure reducing valve reduces the pressure, it enters the two gas lines at a specified pressure. The electromagnetic flow meter monitors the flow rate of Ar gas or SF6 gas. The two gases are introduced into the gas mixing device 102 and mixed in a suitable ratio to achieve precise dilution of SF6. The rotary valve controls the opening and closing process of the Ar gas line or SF6 gas line.

[0064] Diluted SF6 enters the DBD reactor 200. A sufficiently high AC voltage is applied between the electrode rods by a plasma power supply to generate a discharge phenomenon. During the discharge process, a high-frequency, high-voltage AC electric field is formed between the inner and outer electrodes, which excites the dielectric barrier discharge in the DBD reactor 200 and generates plasma. In the plasma environment, SF6 molecules are bombarded by high-energy electrons, ionization and excited-state molecules, and undergo a cracking reaction to generate low-toxicity or non-toxic decomposition products (such as sulfur, fluorides, etc.). The generated decomposition products are easier to adsorb and treat than SF6, which reduces the amount of dilution gas used, reduces cost waste, and effectively improves the degradation efficiency of SF6.

[0065] Furthermore, the absorption unit 300 includes:

[0066] Gas detector 301 is used to detect the SF6 concentration in the gas discharged from DBD reactor 200, and to detect the SF6 concentration before and after degradation in order to calculate its degradation rate.

[0067] The adsorption component 302 is used to degrade and absorb the gas discharged from the DBD reactor 200. The adsorption component is used to adsorb the decomposed products after generation, thereby achieving pollution-free SF6 treatment.

[0068] The rest of the structure is the same as in Example 1.

[0069] Example 3

[0070] Referring to Figure 6, this embodiment differs from the above embodiments in that the adsorption component 302 includes:

[0071] Tower body 302a;

[0072] Liquid storage tank 302b is located at the bottom inside the tower body 302a;

[0073] The packing layer 302c is located in the middle section of the tower body 302a and is used to adsorb and clean harmful gases in the rising gas.

[0074] Spray head 302d is used to spray the treatment liquid in the liquid storage tank 302b from top to bottom, so that it can come into contact with the rising gas and settle.

[0075] Specifically, the gaseous decomposition products generated enter the tower body 302a and rise. The rising gas rises again after being adsorbed by the packing layer 302c. The packing layer 302c uses Raschig rings, which can provide sufficient contact surface between the gas and liquid phases to promote mass transfer and reaction between the gas and liquid. At the same time, due to its high specific surface area, the Raschig ring has a strong adsorption capacity.

[0076] Spray head 302d is connected to liquid storage tank 302b via a pipe. A water pump is installed on the pipe, which draws out the treatment liquid from liquid storage tank 302b. The drawn-out treatment liquid is sprayed out through spray head 302d. The sprayed treatment liquid forms droplets or liquid films downwards. The droplets or liquid films come into countercurrent contact with the upward-moving gas. The gas is in full contact with the treatment liquid inside tower body 302a. Through the mass transfer process at the gas-liquid interface, the pollutants in the gas are absorbed or neutralized by the treatment liquid. The gas treated by the treatment liquid passes through a demister or other gas-liquid separation device at the top of tower body 302a to separate the entrained droplets. The clean gas is discharged from the top of tower body 302a, while the treatment liquid absorbed by the pollutants falls into liquid storage tank 302b. After treatment, it can be recycled or further treated to reduce waste liquid discharge and treatment costs.

[0077] Furthermore, the treatment solution can be any one of water, alkaline solution, or acid solution, and the specific solution used can be determined based on the decomposition products generated after degradation.

[0078] The rest of the structure is the same as in Example 2.

[0079] 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.

[0080] 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 currently considered best mode for carrying out the invention, or those features that are not relevant to implementing the invention) may be omitted.

[0081] 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.

[0082] 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 method for degrading SF6 based on placing a copper ring in the internal electrode of a DBD (Digital Degradation Device), characterized in that: The process involves transporting precisely diluted SF6 to a DBD reactor (200), where an electric field is generated by the discharge of electrode rods in the DBD reactor (200). Several copper rings (201) on the electrode rods are used to change the partial discharge gap and the electric field, thereby completing the degradation of SF6.

2. The method for degrading SF6 based on placing a copper ring with an internal electrode in DBD as described in claim 1, characterized in that: The inner diameter of the copper ring (201) is the same as the outer diameter of the electrode rod, and the thickness of the copper ring (201) is 1.6 mm, with a gap of 25 mm between two adjacent copper rings (201).

3. The method for degrading SF6 based on placing a copper ring with an internal electrode in DBD as described in claim 2, characterized in that: The gas used to dilute SF6 is Ar, and the dosage is: 98% Ar diluted with 2% SF6.

4. The method for degrading SF6 based on placing a copper ring in the internal electrode of a DBD as described in claim 3, characterized in that: The electrode rods in the DBD reactor (200) are powered by a plasma power supply, which is an AC power supply with an AC voltage of 2-4 kW at 10 kHz.

5. The method for degrading SF6 based on placing a copper ring with an internal electrode in DBD as described in claim 4, characterized in that: Both ends of the electrode rod are equipped with grounding wires.

6. A system for degrading SF6 based on placing a copper ring with an internal electrode in a DBD (Diverterless Degradation Device), characterized in that: The method for degrading SF6 based on placing a copper ring with an internal electrode in DBD, as described in claim 1, comprises: The gas supply section (100) is used to prepare a mixture of Ar and SF6 gas of the required concentration. The DBD reactor (200) has several copper rings (201) evenly arranged on the electrode rod inside, and is equipped with an air inlet (202) and an air outlet (203). The absorption unit (300) has its air inlet end connected to the air outlet (203).

7. The system for degrading SF6 based on placing a copper ring with an internal electrode in DBD as described in claim 6, characterized in that: The gas supply section (100) includes: The gas storage unit (101) consists of two gas tanks, which are used to store Ar and SF6 gas respectively. The gas mixer (102) has an inlet end connected to a gas tank and an outlet end connected to a DBD reactor (200), and is used to deliver the proportioned Ar and SF6 mixed gas to the DBD reactor (200).

8. The system for degrading SF6 based on placing a copper ring with an internal electrode in DBD as described in claim 7, characterized in that: The absorption unit (300) includes: A gas detector (301) is used to detect the SF6 concentration in the gas discharged from the DBD reactor (200); Adsorption component (302) is used to degrade and absorb gases discharged from DBD reactor (200).

9. The system for degrading SF6 based on placing a copper ring with an internal electrode in DBD as described in claim 8, characterized in that: The adsorption component (302) includes: Tower body (302a); A liquid storage tank (302b) is located at the bottom inside the tower body (302a); The packing layer (302c) is located in the middle section of the tower body (302a) and is used to adsorb and clean harmful gases in the rising gas. The spray head (302d) is used to spray the treatment liquid in the storage tank (302b) from top to bottom, so that it can come into contact with the rising gas and settle.

10. The system for degrading SF6 based on placing a copper ring with an internal electrode in DBD as described in claim 9, characterized in that: The treatment solution is any one of water, alkaline solution or acid solution.

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