Method and device for degrading SF6 based on jet plasma

Abstract

The invention discloses a method and a device for degrading SF6 based on jet plasma, inert gas is activated and excited to generate plasma, then proportioned SF6 is introduced into a reaction tank, the inert gas in the excited state is subjected to collision reaction in the reaction tank, SF6 broken bonds are decomposed to generate free F atoms and low-fluorine sulfides, O2 is activated and decomposed into free O atoms, and the free F atoms and the low-fluorine sulfides are separated from the low-fluorine sulfides. Reacting free O atoms with the low-fluorine sulfide to generate SO2; according to the method, Ar is introduced into a current piece to excite the current piece to generate plasma, then mixed gas of SF6 and O2 is introduced to be mixed with the plasma, under frequent collision of an excited state Ar *, SF6 and O2 are activated and excited, and broken bonds of SF6 are decomposed and combined with free O atoms to generate SO2; the mixed gas is in full contact with sprayed alkali liquor, and then generated SO2 is absorbed, so that efficient degradation and harmless emission of SF are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of SF6 treatment, and in particular to a method and device for degrading SF6 based on jet plasma. Background Art

[0002] SF6 is a synthetic fluoride with an extremely stable molecular structure and excellent arc extinguishing ability and insulation performance. Since the 1970s, SF6 has been widely used in various electrical equipment, mainly as an insulation and arc extinguishing medium for electrical equipment, including gas-insulated circuit breakers, gas-insulated current transformers, etc. SF6 is the gas with the strongest greenhouse effect among non-CO2 greenhouse gases. It also has a very long atmospheric life and its atmospheric content is increasing year by year. China's SF6 emissions reached 3.2 (2.6-3.8) Gg / yr in 2018, and the emissions are still increasing year by year, and more than 95% of SF6 emissions are generated by the power industry. Since the end of the last century, as environmental protection issues have become more serious year by year, the international community has gradually begun to pay attention to the emission control of SF6. In recent years, with the proposal of the "carbon peak and carbon neutrality" goals, the disposal of SF6 waste gas has become a general trend.

[0003] At present, in order to reduce the damage of SF6 to the atmospheric environment, the main technologies used are SF6 purification and recovery, the use of environmentally friendly insulating alternative gases for SF6, and the degradation and conversion of SF6 waste gas. Among them, the degradation technology is particularly reliable and can achieve a high degradation rate. The dielectric barrier discharge low-temperature plasma method has shown advantages in the degradation of SF6 waste gas, such as strong discharge controllability, high degradation rate, and simple device structure. Therefore, it has great potential for industrial application, and there are related cases in the treatment of SF6 waste gas. Filling a catalyst in a dielectric barrier reactor can effectively improve the degradation rate, energy efficiency, and improve product selectivity. The effect is excellent.

[0004] At present, many scholars have conducted experiments on SF6 waste gas treatment, such as the "Sulfur hexafluoride degradation treatment device based on dielectric barrier discharge" with publication number CN208943805U on June 7, 2019; the "Sulfur hexafluoride discharge degradation device and degradation method" with publication number CN115888343A on April 4, 2023. These patents mainly carry out efficient and harmless degradation of SF6 waste gas. It increases the degradation rate and energy efficiency by adding external gas, and improves the product distribution. The degraded gas is discharged into the atmosphere after adsorption by adsorbent and treatment with alkaline solution.

[0005] The degradation of SF6 is mainly carried out in the form of dielectric barrier discharge. Zhang Xiaoxing and others from Wuhan University used dielectric barrier discharge to conduct degradation experiments on SF6, mainly by changing the input voltage, frequency, dielectric type, background gas, external gas and other conditions to explore the effects of various factors on SF6 degradation. However, the degradation efficiency of SF6 degradation by dielectric barrier discharge plasma is low. When the gas flow rate of 2% SF6 is 150ml / min, the degradation rate reaches 98%, and the dispersion of this type of experimental platform is relatively high, which needs to be solved. Summary of the invention

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

[0007] Therefore, the object of the present invention is to provide a method and device for degrading SF6 based on jet plasma.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions:

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

[0010] The inert gas is activated and excited to generate plasma, and then the proportioned SF6 is introduced into the reaction tank, so that the excited inert gas produces a collision reaction in the reaction tank, SF6 breaks bonds and decomposes to generate free F atoms and low-fluorine sulfides, O2 is activated and decomposed into free O atoms, and the free O atoms react with low-fluorine sulfides to generate SO2.

[0011] As a preferred embodiment of the method for degrading SF6 based on jet plasma according to the present invention, the inert gas is Ar.

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

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

[0014] A device for degrading SF6 based on jet plasma, comprising the above-mentioned method for degrading SF6 based on jet plasma, further comprising:

[0015] A reaction tank, the bottom of which is provided with a processing mechanism;

[0016] a gas source, which is in communication with the processing mechanism;

[0017] Wherein, the gas source can release Ar into the reaction tank, and the processing mechanism can perform an electric field action on Ar. The processing mechanism includes an isolation cylinder arranged at the bottom end of the reaction tank;

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

[0019] As a preferred solution of the device for degrading SF6 based on jet plasma of the present invention, it further comprises a circulation part arranged outside the reaction tank, which comprises a peristaltic pump installed outside the reaction tank, and a spray head arranged at the top of the reaction tank;

[0020] Wherein, the output end of the peristaltic pump is connected to the spray head.

[0021] As a preferred solution of the device for degrading SF6 based on jet plasma according to the present invention, it also includes a guide portion arranged inside the reaction tank, which includes a baffle arranged on the inner wall of the reaction tank and a waterproof umbrella skirt arranged below the baffle.

[0022] As a preferred solution of the device for degrading SF6 based on jet plasma according to the present invention, a fixing plate is fixedly arranged at the bottom of the isolation cylinder, and a current component is arranged on the fixing plate;

[0023] The current element can exert an electric field on Ar.

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

[0025] The beneficial effects of the present invention are as follows: Ar is introduced into the current element to excite it to generate plasma, and then a mixed gas of SF6 and O2 is introduced to mix with the plasma, and under the frequent collision of the excited Ar*, SF6 and O2 are activated and excited, SF6 is decomposed by bond breaking and combines with free O atoms to generate SO2; the mixed gas is fully in contact with the sprayed alkali solution, and then absorbs the generated SO2, thereby realizing the efficient degradation and harmless emission of SF. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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:

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

[0028] Figure 2 It is an enlarged view of part of the structure of the present invention. DETAILED DESCRIPTION

[0029] 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.

[0030] 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.

[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 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.

[0032] 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.

[0033] Example 1

[0034] Reference Figure 1-Figure 2 , provides a method and device for degrading SF6 based on jet plasma, comprising:

[0035] The inert gas is activated and excited to generate plasma, and then the proportioned SF6 is introduced into the reaction tank 100, so that the excited inert gas produces a collision reaction in the reaction tank 100, SF6 is decomposed by bond breaking to generate free F atoms and 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;

[0036] The inert gas (intake flow rate: 9 L / min) enters the reverse tank through a separate gas path, and 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 gas path. The inert gas is excited by the active method. Under the frequent collision of the excited inert gas, SF6 and O2 are activated and excited, so that SF6 breaks bonds and decomposes and combines with free O atoms to generate SO2. Compared with SF6, SO2 is easier to remove and degrade, thereby solving the problem that SF6 is difficult to degrade.

[0037] Furthermore, the inert gas is Ar.

[0038] Furthermore, the inert gas is excited to generate plasma through the action of the electric field; coaxial positive and negative electrodes are provided in the reaction tank 100, and the inert gas enters the coaxial positive and negative motor room through a separate gas path (intake 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 alkali solution is sprayed in the reaction tank 100, and the alkali solution contacts the mixed gas in the reaction tank 100 to absorb the generated SO2;

[0040] The degraded SF6 mixed gas gradually rises under the action of the airflow, fully contacts with the sprayed alkali solution, removes the generated SO2, and realizes the harmless emission of SF6; at the same time, the circulating alkali solution absorbs the heat generated by the jet plasma reactor, achieves the effect of cooling, and ensures the long-term and stable operation of the equipment.

[0041] Operation process:

[0042] S1: Connect the gas circuit inside the equipment to ensure that the positive and negative electrodes of the power supply (203c) are in correct and reliable contact; the gas circuit includes the Ar gas circuit and the SF6 and O2 mixed gas circuit. Connect each part according to the attached Figure 1 Tight connections shown;

[0043] S2: First, pass the background gas to detect the air tightness of the device to prevent the leakage of toxic gas during the reaction from causing harm to the workers and ensure that the reaction proceeds stably and orderly;

[0044] S3: Check the liquid level in the liquid collecting tank regularly, replace the liquid collecting tank, replace the alkali solution regularly, and clean the solid sediment in the gas washing tank;

[0045] S4: spray alkali solution in the reaction tank 100, turn on the power supply 203c to set the input power; set the electromagnetic flowmeter to set the air intake flow of each gas path according to the demand, and the SF6 degradation reaction begins;

[0046] S4: Ar (inlet flow rate: 9L / min) is introduced between the coaxial positive and negative electrodes, and Ar is activated and excited to generate plasma under the action of the electric field; another gas path is introduced with a mixed gas of SF6 and O2 (SF6 flow rate: 0.5L / min, O2 flow rate: 0.5L / min), which is excited to generate plasma and collide with SF6 and O2, so that SF6 gradually breaks bonds and decomposes to generate free F atoms and low-fluorine sulfides, and O2 is activated and decomposed into free O atoms, and the free O atoms react with low-fluorine sulfides to generate SO2 that is easy to handle;

[0047] S5: The degraded SF6 mixed gas gradually rises under the action of the airflow, fully contacts with the sprayed alkali solution, removes the generated SO2, and realizes the harmless emission of SF6;

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

[0049] Under the frequent collisions of excited Ar*, SF6 and O2 are activated and excited, causing SF6 to break bonds and decompose and combine with free O atoms to generate SO2; then the mixed gas gradually rises under the action of the airflow, fully contacts with the alkaline solution above to absorb the generated SO2, and realizes the harmless emission of SF6.

[0050] Example 2

[0051] Reference Figure 1-Figure 2 , this embodiment is different from the first embodiment in that: this embodiment proposes a device for degrading SF6 based on jet plasma, including the above-mentioned method for degrading SF6 based on jet plasma, and also includes,

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

[0053] A gas source 300, which is connected to the processing mechanism 200;

[0054] The gas source 300 can release Ar into the reaction tank 100, and the processing mechanism 200 can perform an electric field action on the Ar;

[0055] The gas source 300 includes a first gas path 301 and a second gas path 302, and the first gas path 301 and the second gas path 302 are both connected to the processing mechanism 200, wherein an electromagnetic flowmeter is arranged on each gas path to control the flow rate of the Ar, SF6 and O2 mixed gas inlet, 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, and the second gas path 302 passes the SF6 and O2 mixed gas into the reaction tank 100, and 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, and SF6 is decomposed by breaking bonds and combined with free O atoms to generate SO2.

[0056] Furthermore, the treatment mechanism 200 includes an isolation cylinder 201 disposed at the bottom of the reaction tank 100; an alkali solution pool 204 is formed between the outer wall of the isolation cylinder 201 and the inner wall of the reaction tank 100;

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

[0058] Furthermore, it also includes a flow guide 500 disposed inside the reaction tank 100, which includes a baffle 501 disposed on the inner wall of the reaction tank 100, and a waterproof shed 502 disposed below the baffle 501;

[0059] After SF6 breaks bonds and decomposes and combines with free O atoms to generate SO2; the degraded SF6 mixed gas gradually rises under the action of the airflow, and flows 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 fully in contact with the sprayed alkali solution, thereby improving the degradation effect; at the same time, the waterproof umbrella skirt 502 protects the jet plasma reaction gas below to prevent the alkali 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 the 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 passed between the ground electrode 203b and the high-voltage electrode 203a, and Ar is passed between the two to excite them to generate plasma. The second gas path 302 is passed between the isolation tube 201 and the high-voltage electrode 203a to mix the mixed gas of SF6 and O2 with the plasma, and then the mixed gas can collide with the excited Ar*.

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

[0064] Ar is introduced into the current element 203 to excite it to generate plasma, and then a mixed gas of SF6 and O2 is introduced to mix with the plasma. Under the frequent collision of the excited Ar*, SF6 and O2 are activated and excited, and SF6 breaks bonds and decomposes and combines with free O atoms to generate SO2; the mixed gas is fully in contact with the sprayed alkali solution, and then absorbs the generated SO2, thereby realizing the efficient degradation and harmless emission of SF6.

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

[0066] Example 3

[0067] Reference Figure 1-Figure 2 , this embodiment is different from the above embodiment in that: it also includes a circulation part 400 arranged outside the reaction tank 100, which includes a peristaltic pump 401 installed outside the reaction tank 100, and a spray head 402 arranged at the top of the reaction tank 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 alkali solution pool 204, and the alkali solution in the alkali solution pool 204 is transported to the spray head 402 through the peristaltic pump 401. The spray head 402 sprays the alkali solution in the reverse tank. The waterproof umbrella skirt 502 and the baffle 501 cooperate to make the SF6 degradation tail gas flow between the waterproof umbrella skirt 502 and the baffle 501, and fully contact with the alkali solution sprayed by the spray head 402.

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

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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 method and device for degrading SF6 based on jet plasma, characterized in that: include, The inert gas is activated and excited to generate plasma, and then the proportioned SF6 is introduced into the reaction tank (100), so that the excited inert gas produces a collision reaction in the reaction tank (100), SF6 breaks bonds and decomposes to generate free F atoms and low-fluorine sulfides, O2 is activated and decomposed into free O atoms, and the free O atoms react with the low-fluorine sulfides to generate SO2.

2. The method and device for degrading SF6 based on jet plasma according to claim 1, characterized in that: The inert gas is Ar.

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

4. The method and device for degrading SF6 based on jet plasma according to claim 3, characterized in that: Alkaline solution is sprayed into the reaction tank (100), and the alkaline solution contacts the mixed gas in the reaction tank (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 according to any one of claims 1 to 4 further comprises: A reaction tank (100) having a processing mechanism (200) disposed at its bottom; A gas source (300) connected to the processing mechanism (200); The gas source (300) can release Ar into the reaction tank (100), and the processing mechanism (200) can perform an electric field action on the Ar.

6. The device for degrading SF6 based on jet plasma according to claim 5, characterized in that: The processing mechanism (200) comprises an isolation cylinder (201) arranged at the bottom end of the reaction tank (100); An alkaline solution pool (204) is formed between the outer wall of the isolation cylinder (201) and the inner wall of the reaction tank (100).

7. The device for degrading SF6 based on jet plasma according to claim 6, characterized in that: It also includes a circulation unit (400) arranged outside the reaction tank (100), which includes a peristaltic pump (401) installed outside the reaction tank (100) and a spray head (402) arranged at the top of the reaction tank (100); Wherein, the output end of the peristaltic pump (401) is connected to the spray head (402).

8. The device for degrading SF6 based on jet plasma according to claim 7, characterized in that: It also includes a flow guide (500) arranged inside the reaction tank (100), which includes a baffle (501) arranged on the inner wall of the reaction tank (100), and a waterproof shed (502) arranged below the baffle (501).

9. The device for degrading SF6 based on jet plasma according to claim 8, characterized in that: A fixing plate (202) is fixedly provided at the bottom of the isolation cylinder (201), and a current component (203) is provided on the fixing plate (202); The current element (203) is capable of exerting an electric field on Ar.

10. The device for degrading SF6 based on jet plasma according to claim 8 or 9, characterized in that: An injection port (101) is provided on one side of the reaction tank (100), and an exhaust port (102) is provided on one side of the reaction tank (100) near the top.

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