Method and device for degrading SF 6 based on jet plasma

Abstract

Disclosed in the present invention are a method and device for degrading SF6 based on jet plasma. The method comprises: activating and exciting an inert gas to generate plasma, and then introducing proportioned SF6 into a reaction tank, so that the inert gas in an excited state is subjected to a collision reaction in the reaction tank, and thus SF6 decomposes by bond breaking to generate free F atoms and a low-fluorine sulfide, O2 is activated and decomposed into free O atoms, and the free O atoms react with the low-fluorine sulfide to generate SO2. In the present invention, Ar is introduced into a current piece and is excited to generate plasma, and then a mixed gas of SF6 and O2 is introduced to mix with the plasma; under the frequent collision of Ar* in an excited state, SF6 and O2 are activated and excited, and SF6 decomposes by bond breaking and combines with free O atoms to generate SO2; and the mixed gas is in full contact with a sprayed basic solution, and then absorbs the generated SO2, thereby achieving efficient degradation and harmless emission of SF.

Description

A method and apparatus for degrading SF6 based on jet plasma Technical Field

[0001] This invention relates to the technical field of SF6 treatment, and in particular to a method and apparatus for degrading SF6 based on jet plasma. Background Technology

[0002] SF6 is a synthetic fluoride with an extremely stable molecular structure, possessing excellent arc-quenching and insulating properties. Since the 1970s, SF6 has been widely used in various electrical equipment, primarily as an insulating and arc-quenching medium, including gas-insulated circuit breakers and gas-insulated current transformers. As the most potent greenhouse gas among non-carbon dioxide greenhouse gases, SF6 also has an extremely long atmospheric lifetime, and its atmospheric concentration is increasing year by year. China's SF6 emissions reached 3.2 (2.6-3.8) Gg / yr in 2018, and emissions continue to increase annually, with over 95% of SF6 emissions originating from the power industry. Since the end of the last century, with the increasing severity of environmental problems, the international community has gradually begun to pay attention to SF6 emission control. In recent years, with the proposal of the "carbon peaking and carbon neutrality" goals, the treatment of SF6 waste gas has become an inevitable trend.

[0003] Currently, to reduce the damage of SF6 to the atmospheric environment, the main technologies employed include SF6 purification and recovery, the use of environmentally friendly insulating alternatives to SF6, and the degradation and conversion of SF6 waste gas. Among these, degradation technology is particularly reliable and can achieve high degradation rates. The dielectric barrier discharge low-temperature plasma method has demonstrated advantages in SF6 waste gas degradation, including strong discharge controllability, high degradation rate, and simple device structure, thus possessing significant industrial application potential. There are already relevant case studies in SF6 waste gas treatment. Filling the dielectric barrier reactor with a catalyst can effectively improve the degradation rate, energy efficiency, and product selectivity, resulting in excellent performance.

[0004] Currently, many scholars have conducted experiments on SF6 waste gas treatment. For example, the patent "Sulfur hexafluoride degradation treatment device based on dielectric barrier discharge" published on June 7, 2019, and the patent "Sulfur hexafluoride discharge degradation device and degradation method" published on April 4, 2023, mainly carry out efficient and harmless degradation of SF6 waste gas. It improves the degradation rate and energy efficiency by adding external gas and improves the product distribution. The degraded gas is then discharged into the atmosphere after being adsorbed by adsorbent and treated with alkaline solution.

[0005] The degradation of SF6 is mainly achieved through dielectric barrier discharge (DBD). Zhang Xiaoxing et al. from Wuhan University conducted experiments using DBD to degrade SF6, exploring the effects of various factors on SF6 degradation by changing input voltage, frequency, dielectric type, background gas, and applied gas. However, this DBD plasma method exhibits low degradation efficiency for SF6; only 98% of 2% SF6 was degraded at a gas flow rate of 150 ml / min. Furthermore, the experimental platform in this field suffers from high dispersion, a problem that needs further investigation. Summary of the Invention

[0006] In view of the problems existing in the above-mentioned methods and apparatuses for degrading SF6 based on jet plasma, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to provide a method and apparatus for degrading SF6 based on jet plasma.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] A method for degrading SF6 based on jet plasma, comprising,

[0010] Inert gas is activated and excited to generate plasma. Then, SF6 in the specified ratio is introduced into the reaction vessel, causing the excited inert gas to undergo a collision reaction in the reaction vessel. SF6 breaks bonds and decomposes to generate free F atoms and low-fluorine sulfides. O2 is activated and decomposed into free O atoms. The free O atoms react with low-fluorine sulfides to generate SO2.

[0011] In a preferred embodiment of the jet plasma-based SF6 degradation method of the present invention, the inert gas is Ar.

[0012] In a preferred embodiment of the method for degrading SF6 based on jet plasma according to the present invention, the inert gas is excited to generate plasma by an electric field.

[0013] As a preferred embodiment of the method for degrading SF6 based on jet plasma according to the present invention, wherein: an alkaline solution is sprayed into the reaction vessel, and the alkaline solution comes into contact with the mixed gas in the reaction vessel to absorb the generated SO2.

[0014] An apparatus for degrading SF6 based on jet plasma, comprising the aforementioned method for degrading SF6 based on jet plasma, and further comprising,

[0015] The reaction vessel has a processing mechanism at its bottom.

[0016] The gas source is connected to the processing unit;

[0017] The gas source can release Ar into the reaction vessel, and the processing mechanism can apply an electric field to Ar. The processing mechanism includes an isolation cylinder located at the bottom of the reaction vessel.

[0018] In a preferred embodiment of the device for degrading SF6 based on jet plasma according to the present invention, an alkaline solution pool is formed between the outer wall of the isolation cylinder and the inner wall of the reaction vessel.

[0019] As a preferred embodiment of the device for degrading SF6 based on jet plasma according to the present invention, it further includes a circulation section located outside the reaction vessel, which includes a peristaltic pump installed outside the reaction vessel and a spray head located at the top inside the reaction vessel.

[0020] The peristaltic pump output is connected to the spray head.

[0021] As a preferred embodiment of the apparatus for degrading SF6 based on jet plasma according to the present invention, it further includes a flow guide section disposed inside the reaction vessel, which includes a baffle disposed on the inner wall of the reaction vessel and a waterproof umbrella skirt disposed below the baffle.

[0022] In a preferred embodiment of the device for degrading SF6 based on jet plasma according to the present invention, a fixing plate is fixedly provided at the bottom of the isolation cylinder, and a current-carrying element is provided on the fixing plate;

[0023] The current-carrying element is capable of applying an electric field to Ar.

[0024] As a preferred embodiment of the device for degrading SF6 based on jet plasma according to the present invention, wherein: an injection port is provided on one side of the reaction vessel, and an exhaust port is opened on one side of the reaction vessel near the top.

[0025] The beneficial effects of this invention are as follows: Ar is introduced into the current device to excite it and generate plasma. Then, a mixed gas of SF6 and O2 is introduced to mix with the plasma. Under the frequent collisions of the excited Ar*, SF6 and O2 are activated and excited. SF6 breaks bonds and decomposes, and combines with free O atoms to generate SO2. The mixed gas comes into full contact with the sprayed alkaline solution, and then absorbs the generated SO2, thereby achieving efficient degradation and harmless emission of SF6. Attached Figure Description

[0026] 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:

[0027] Figure 1 is a schematic diagram of the overall structure of the present invention.

[0028] Figure 2 is an enlarged view of part of the structure of the present invention. Detailed Implementation

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] Example 1

[0034] Referring to Figures 1-2, a method and apparatus for degrading SF6 based on jet plasma are provided, including,

[0035] Inert gas is activated and excited to generate plasma. Then, SF6 in the specified ratio is introduced into reaction vessel 100, so that the excited inert gas undergoes a collision reaction in reaction vessel 100. SF6 breaks bonds and decomposes to generate free F atoms and low-fluorine sulfides. O2 is activated and decomposed into free O atoms. The free O atoms react with low-fluorine sulfides to generate SO2.

[0036] An inert gas (inlet flow rate: 9 L / min) enters the reverse tank through a separate gas path. SF6 and O2 (SF6 flow rate: 0.5 L / min, O2 flow rate: 0.5 L / min) are mixed and enter the reaction tank (100) through a single gas path. The inert gas is activated by a method. Under the frequent collisions of the excited inert gas, SF6 and O2 are activated and excited, causing SF6 to break bonds and decompose, and combine with free O atoms to generate SO2. Compared with SF6, SO2 is easier to remove and degrade, thus solving the problem of SF6 being difficult to degrade.

[0037] Furthermore, the inert gas is Ar.

[0038] Furthermore, the inert gas is excited to generate plasma by the action of an electric field; the reaction vessel 100 is equipped with coaxial positive and negative electrodes, and the inert gas enters the coaxial positive and negative electrode spacer through a separate gas path (inlet flow rate: 9L / min), and the inert gas is activated and excited to generate plasma under the action of the electric field.

[0039] Furthermore, an alkaline solution is sprayed into the reaction vessel 100, and the alkaline solution comes into contact with the mixed gas inside the reaction vessel 100 to absorb the generated SO2.

[0040] The degraded SF6 mixture gradually rises under the action of airflow, and comes into full contact with the sprayed alkaline solution to remove the generated SO2, thus achieving harmless emission of SF6. At the same time, the circulating alkaline solution absorbs the heat generated by the jet plasma reactor, achieving a cooling effect and ensuring long-term stable operation of the equipment.

[0041] Operation process:

[0042] S1: Connect the gas path section inside the equipment to ensure that the positive and negative terminals of the power supply (203c) are in correct and reliable contact; the gas path section includes the Ar gas path and the SF6 and O2 mixed gas path, and connect each part tightly as shown in Figure 1;

[0043] S2: First, introduce the background gas detection device to check for air tightness, to prevent toxic gas leakage during the reaction from harming the staff and to ensure that the reaction proceeds stably and orderly;

[0044] S3: Regularly check the liquid level in the collection tank and replace the collection tank. Regularly replace the alkali solution and clean the solid sediment in the gas washing tank.

[0045] S4: Spray alkaline solution into reaction vessel 100, turn on power supply 203c and set input power; set the electromagnetic flow meter to set the inlet flow rate of each gas path according to requirements, and the SF6 degradation reaction begins;

[0046] S4: Ar (inlet flow rate: 9 L / min) is introduced between the coaxial positive and negative electrodes. Under the action of the electric field, Ar is activated and excited to generate plasma. Another gas path introduces a mixture of SF6 and O2 (SF6 flow rate: 0.5 L / min, O2 flow rate: 0.5 L / min), which excites the plasma to collide and react with SF6 and O2. This causes SF6 to gradually break bonds and decompose to generate free F atoms and low-fluorine sulfides. O2 is activated and decomposed into free O atoms. The free O atoms react with low-fluorine sulfides to generate SO2, which is easy to handle.

[0047] S5: The degraded SF6 mixture gradually rises under the action of airflow, and comes into full contact with the sprayed alkaline solution to remove the generated SO2, thus achieving harmless emission of SF6.

[0048] S6: After the degradation reaction is complete, first close the pressure reducing valve of SF6 gas to keep the reaction device running stably. After five minutes, turn off the power supply 203c and keep introducing Ar to completely exhaust the SF6 tail gas in the reactor. After five minutes, turn off all equipment.

[0049] Frequent collisions with excited Ar* activate and excite SF6 and O2, causing SF6 to break bonds and decompose, combining with free O atoms to generate SO2; then the mixed gas gradually rises under the action of airflow, fully contacting the alkaline solution above to absorb the generated SO2, thus achieving the harmless emission of SF6.

[0050] Example 2

[0051] Referring to Figures 1-2, this embodiment differs from the first embodiment in that: this embodiment proposes an apparatus for degrading SF6 based on jet plasma, including the aforementioned method for degrading SF6 based on jet plasma, and further comprising,

[0052] The reaction vessel 100 has a processing mechanism 200 at its bottom end;

[0053] Gas source 300, which is connected to processing unit 200;

[0054] Among them, the gas source 300 can release Ar into the reaction vessel 100, and the processing mechanism 200 can apply an electric field to Ar.

[0055] The gas source 300 includes a first gas path 301 and a second gas path 302, both of which are connected to the processing mechanism 200. Each gas path is equipped with an electromagnetic flowmeter to control the flow rate of the Ar, SF6 and O2 mixed gas. The first gas path 301 is connected to an Ar gas cylinder, and the second gas path 302 is connected to an SF6 gas cylinder and an O2 gas cylinder. The second gas path 302 introduces the SF6 and O2 mixed gas into the reaction vessel 100, while the processing mechanism 200 can excite Ar to generate plasma. Through the collision reaction between the mixed gas and the excited Ar, SF6 and O2 are activated and excited. SF6 breaks bonds and decomposes, and combines with free O atoms to generate SO2.

[0056] Furthermore, the processing mechanism 200 includes an isolation cylinder 201 located at the bottom of the reaction vessel 100; an alkaline solution pool 204 is formed between the outer wall of the isolation cylinder 201 and the inner wall of the reaction vessel 100.

[0057] By providing an alkali solution tank 204 in the reaction tank 100, the alkali solution in the alkali solution tank 204 can be sprayed into the reaction tank 100. The mixed gas and the sprayed alkali solution fully contact and absorb the generated SO2, thereby achieving efficient degradation and harmless emission of SF6.

[0058] Furthermore, it also includes a flow guide 500 located inside the reaction vessel 100, which includes a baffle 501 located on the inner wall of the reaction vessel 100 and a waterproof umbrella skirt 502 located below the baffle 501.

[0059] After SF6 breaks its bonds and combines with free O atoms to generate SO2, the degraded SF6 mixture gradually rises under the action of the airflow. It moves upward from both sides under the obstruction of the waterproof umbrella skirt 502. The SF6 degradation tail gas flows upward between the waterproof umbrella skirt 502 and the baffle 501, ensuring that the gas is in full contact with the sprayed alkaline solution and improving the degradation effect. At the same time, the waterproof umbrella skirt 502 protects the reaction gas of the jet plasma below, preventing the alkaline solution from affecting the SF6 degradation reaction.

[0060] Furthermore, a fixing plate 202 is fixedly provided at the bottom of the isolation cylinder 201, and a current element 203 is provided on the fixing plate 202; wherein, the current element 203 can exert an electric field on Ar;

[0061] The current element 203 includes a high-voltage electrode 203a and a ground electrode 203b mounted on a fixed plate 202. The high-voltage electrode 203a is located inside the isolation cylinder 201, and the ground electrode 203b is located inside the high-voltage electrode 203a. Both the high-voltage electrode 203a and the ground electrode 203b are connected to a power source 203c.

[0062] The first gas path 301 is introduced between the ground electrode 203b and the high-voltage electrode 203a. The first gas path 301 introduces Ar into the space between the two to excite and generate plasma. The second gas path 302 is introduced between the isolation cylinder 201 and the high-voltage electrode 203a to mix the SF6 and O2 mixture with the plasma, thereby enabling the mixture to collide with the excited Ar*.

[0063] Furthermore, an injection port 101 is provided on one side of the reaction vessel 100, and an exhaust port 102 is provided on one side of the reaction vessel 100 near the top. The injection port 101 allows alkaline solution to be added to the reaction vessel 100, and the exhaust port 102 allows the degraded gas to be discharged from the reaction vessel 100.

[0064] Ar is introduced into the current device 203 to excite it and generate plasma. Then, a mixed gas of SF6 and O2 is introduced to mix with the plasma. Under the frequent collisions of the excited Ar*, SF6 and O2 are activated and excited. SF6 breaks bonds and decomposes and combines with free O atoms to generate SO2. The mixed gas comes into full contact with the sprayed alkaline solution and then absorbs the generated SO2, realizing the efficient degradation and harmless emission of SF6.

[0065] The rest of the structure is the same as in Example 1.

[0066] Example 3

[0067] Referring to Figures 1-2, this embodiment differs from the above embodiments in that it also includes a circulation section 400 located outside the reaction vessel 100, which includes a peristaltic pump 401 installed outside the reaction vessel 100 and a spray head 402 located at the top inside the reaction vessel 100; wherein, the output end of the peristaltic pump 401 is connected to the spray head 402.

[0068] The input end of the peristaltic pump 401 is connected to the alkaline solution tank 204. The peristaltic pump 401 transports the alkaline solution in the alkaline solution tank 204 to the spray head 402. The spray head 402 sprays the alkaline solution into the reverse tank. The waterproof umbrella skirt 502 and the partition 501 work together to make the SF6 degradation exhaust gas flow between the waterproof umbrella skirt 502 and the partition 501, so that it can fully contact the alkaline solution sprayed by the spray head 402.

[0069] The rest of the structure is the same as in Example 2.

[0070] 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.), installation 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.

[0071] 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.

[0072] 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.

[0073] 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 and apparatus for degrading SF6 based on jet plasma, characterized in that: include, Inert gas is activated and excited to generate plasma. Then, SF6 in the specified ratio is introduced into the reaction vessel (100) to cause the excited inert gas to undergo a collision reaction in the reaction vessel (100). SF6 breaks bonds and decomposes to generate free F atoms and low-fluorine sulfides. O2 is activated and decomposed into free O atoms. The free O atoms react with low-fluorine sulfides to generate SO2.

2. The method and apparatus for degrading SF6 based on jet plasma as described in claim 1, characterized in that: The inert gas is Ar.

3. The method and apparatus for degrading SF6 based on jet plasma as described in claim 2, characterized in that: The inert gas is excited by an electric field to generate plasma.

4. The method and apparatus for degrading SF6 based on jet plasma as described in claim 3, characterized in that: Alkali solution is sprayed into the reaction vessel (100), and the alkali solution comes into contact with the mixed gas in the reaction vessel (100) to absorb the generated SO2.

5. A device for degrading SF6 based on jet plasma, characterized in that, The method for degrading SF6 based on jet plasma as described in any one of claims 1-4 further includes, The reaction vessel (100) has a processing mechanism (200) at its bottom end; A gas source (300) is connected to a processing unit (200); The gas source (300) can release Ar into the reaction vessel (100), and the processing mechanism (200) can apply an electric field to Ar.

6. The apparatus for degrading SF6 based on jet plasma as described in claim 5, characterized in that: The processing mechanism (200) includes an isolation cylinder (201) located at the bottom of the reaction vessel (100); An alkaline solution pool (204) is formed between the outer wall of the isolation cylinder (201) and the inner wall of the reaction vessel (100).

7. The apparatus for degrading SF6 based on jet plasma as described in claim 6, characterized in that: It also includes a circulation section (400) located outside the reaction vessel (100), which includes a peristaltic pump (401) installed outside the reaction vessel (100) and a spray head (402) located at the top inside the reaction vessel (100); The peristaltic pump (401) output end is connected to the spray head (402).

8. The apparatus for degrading SF6 based on jet plasma as described in claim 7, characterized in that: It also includes a flow guide (500) disposed inside the reaction vessel (100), which includes a baffle (501) disposed on the inner wall of the reaction vessel (100) and a waterproof umbrella skirt (502) disposed below the baffle (501).

9. The apparatus for degrading SF6 based on jet plasma as described in claim 8, characterized in that: The bottom of the isolation cylinder (201) is fixedly provided with a fixing plate (202), and the fixing plate (202) is provided with a current element (203); The current-carrying element (203) is capable of applying an electric field to Ar.

10. The apparatus for degrading SF6 based on jet plasma as described in claim 8 or 9, characterized in that: The reaction vessel (100) has an injection port (101) on one side and an exhaust port (102) on one side near the top.

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