Device and method for preparing NF3 by activating SF6 through dielectric barrier discharge

Abstract

The invention relates to the technical field of efficient sulfur degradation and resource conversion and utilization of sulfur hexafluoride, and discloses a device for preparing NF3 by activating SF6 through dielectric barrier discharge, the device comprises a reaction unit, a gas supply unit is arranged on the left side of the reaction unit, a power supply unit is arranged on the top of the reaction unit, and a condensation unit is arranged on the right side of the reaction unit. The treatment unit is arranged at the bottom of the condensation unit, the reaction unit is connected with the gas supply unit through a gas pipe, the reaction unit is electrically connected with the power supply unit, and the reaction unit is connected with the condensation unit through a gas pipe; according to the method, a dielectric barrier discharge technology is adopted, efficient discharge can be achieved under normal pressure or low pressure, a large number of high-energy electrons and active particles are generated, chemical reaction can be promoted, NH3 serves as a nitrogen source, fluorine-rich molecules SF6 serve as a fluorine source, and NH3 reacts with low-fluorine sulfide generated by decomposition of SF6 through broken-bond decomposition under the action of DBD plasma, so that the sulfur-rich sulfur-rich nitrogen-rich sulfur-rich sulfur-rich sulfur-rich sulfur-rich sulfur-rich sulfur-rich sulfur-rich sulfur-rich sulfur-rich sulfur-rich sulfur-rich sulfur-rich sulfur-rich sulfur- and synthesizing a target product NF3.

Description

Technical Field

[0001] The invention relates to the technical field of efficient degradation and resource conversion and utilization of sulfur hexafluoride, and in particular to a device and a method for preparing NF3 by activating SF6 through dielectric barrier discharge. Background Art

[0002] Sulfur hexafluoride (SF6) is an inorganic compound that is colorless, odorless, non-toxic and non-flammable at room temperature and pressure. Its molecular structure is octahedral, with a small bonding distance and high bonding energy, so it has extremely high stability. SF6 has excellent insulation and arc extinguishing properties. It is widely used in insulation and arc extinguishing materials for power equipment such as high-voltage switches, large-capacity transformers, gas-insulated equipment and circuit breakers, ensuring the stable operation of the power system. However, as the power system is in long-term operation, SF6 will be discharged during overhaul and maintenance. As a strong greenhouse gas, its greenhouse effect value (GWP) is 23,500 times, and direct emissions will have a great impact on the environment. In order to limit SF6 emissions, it is currently mainly degraded. The main methods for degrading SF6 gas are pyrolysis, photocatalytic degradation, thermal catalysis and plasma. The plasma method uses the active substances in the plasma to react with SF6 to decompose SF6 in a short time. The reaction conditions are mild, the energy consumption is low, and the degradation rate is high. It is a relatively popular degradation method. At present, there is a lack of research on the resource utilization of SF6.

[0003] In recent years, nitrogen trifluoride (NF3) has been widely used in semiconductor manufacturing and microelectronics industry as an excellent electronic special gas. The traditional method of synthesizing NF3 uses nitrogen and fluorine as raw materials. Fluorine itself is extremely corrosive and toxic. The two gases need to be synthesized under high temperature and high pressure conditions. Since the nitrogen-nitrogen triple bond is very stable, a catalyst is usually required to reduce the activation energy of the reaction to promote the reaction. High temperature conditions will lead to poor selectivity of the reaction and unsatisfactory distribution of the reaction products. The traditional synthesis method has problems such as low yield, poor product selectivity, poor safety and high cost. SF6, as a fluorine-rich molecule, can decompose SF6 to produce fluoride ions and low-fluorine sulfides under the action of dielectric barrier discharge plasma. It can be used as a strong fluorinating agent for the synthesis of fluorine-containing electronic special gases. Under the action of plasma, a large amount of active substances can be generated to collide with it to dissociate SF6. However, due to the extremely stable chemical properties of SF6, SF6 will undergo a self-recovery reaction after bond breaking and decomposition to regenerate SF6. As a reducing gas, NH3 can effectively promote the decomposition of SF6, and can effectively inhibit the compound reaction after SF6 bond breaking, so that the SF6 decomposition reaction proceeds in the forward direction, which can accelerate the dissociation process and significantly improve the SF6 degradation rate. At the same time, NH3 can be used as a nitrogen source, which can react quickly with SF6 to synthesize NF3 high-value electronic special gas. Therefore, a device and preparation method for preparing NF3 by dielectric barrier discharge activation of SF6 are proposed. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a device and method for preparing NF3 by activating SF6 by dielectric barrier discharge, which has the advantages of mild reaction conditions, safety and reliability, good degradation effect, high synthesis rate, etc., and solves the problems mentioned in the above background technology.

[0005] In order to achieve the above-mentioned purpose of good degradation effect and resource-based synthesis of fluorine-containing electronic special gases, the present invention provides the following technical solutions: a device for preparing NF3 by dielectric barrier discharge activation of SF6, comprising a reaction unit, a gas supply unit is arranged on the left side of the reaction unit, a power supply unit is arranged on the top of the reaction unit, a condensation unit is arranged on the right side of the reaction unit, and a processing unit is arranged at the bottom of the condensation unit; The reaction unit is connected to the gas supply unit through an air pipe, the reaction unit is electrically connected to the power supply unit, the reaction unit is connected to the condensation unit through an air pipe, and the condensation unit is connected to the processing unit through an air pipe; The reaction unit comprises a coaxial DBD reactor, which is composed of an inner electrode tube and an outer electrode tube, a flange is fixedly connected to the outer surface of the outer electrode tube, and a tubular furnace is arranged on the outer surface of the coaxial DBD reactor; The inner electrode tube is composed of a quartz glass tube and a copper rod, and the outer electrode tube is made of quartz glass; The condensation unit includes a first condensation tank and a second condensation tank, the first condensation tank and the second condensation tank are connected by an air pipe, the left side of the first condensation tank is connected to the reaction unit by an air pipe, the first condensation tank and the second condensation tank are both provided with an exhaust port and a water outlet, the first condensation tank is filled with an ethylene glycol mixed solution, the second condensation tank is filled with liquid nitrogen, and the first condensation tank and the second condensation tank are both cooled by a condenser.

[0006] Preferably, the gas supply unit includes a gas distributor, the gas inlet of the gas distributor is connected to an SF6 gas supply bottle, an Ar gas supply bottle and an NH3 gas supply bottle through a gas pipe, the outer surfaces of the gas pipes connecting the SF6 gas supply bottle, the Ar gas supply bottle, the NH3 gas supply bottle and the gas distributor are all provided with pressure reducing valves, and the outer surface of the gas pipe connecting the gas distributor and the coaxial DBD reactor is provided with an electromagnetic flowmeter.

[0007] Preferably, the power supply unit is a plasma power supply, and the discharge area on the outer surface of the inner electrode tube is wrapped by a metal mesh and electrically connected to the plasma power supply.

[0008] Preferably, the processing unit consists of an alkali solution treatment tank and an NF3 collection tank, the top of the alkali solution treatment tank is connected to the water outlet of the first condensation tank by an air pipe, and the top of the NF3 collection tank is connected to the water outlet of the second condensation tank by an air pipe.

[0009] Preferably, the temperature of liquid nitrogen inside the second condensing tank is -145°C, and the temperature of the ethylene glycol-water mixed solution inside the first condensing tank is -75°C.

[0010] Preferably, a method for preparing NF3 by activating SF6 by dielectric barrier discharge, the specific steps are: S1: SF6 gas supply bottle, Ar gas supply bottle, NH3 gas supply bottle are connected to the gas distributor through gas pipes, and the plasma power supply is connected to the outer surface of the outer electrode tube; S2: connecting the coaxial DBD reactor, the first condensation tank, the second condensation tank, the alkali solution treatment tank, and the NF3 collection tank; S3: First open the valves of the SF6 gas supply bottle, Ar gas supply bottle, and NH3 gas supply bottle, then open the pressure reducing valve and the gas distributor, introduce the gas according to the set ratio, and fully mix them in the gas distributor; S4: The mixed gas is sent into the discharge area of ​​the coaxial DBD reactor for reaction, thereby achieving the degradation of SF6 gas and the synthesis of NF3 electronic special gas; S5: At the same time, the tubular furnace heats the coaxial DBD reactor. After the temperature is raised to 100°C, the S element generated by the reaction can be sublimated and will not block the gas outlet. At the same time, the increase in reaction temperature can accelerate the chemical reaction and will not affect the subsequent separation of the target gas product; S6: sending the synthesized NF3 gas and other gaseous products such as SO2, SO2F2, SOF2, SOF4, SF4, SiH4, HF and SiF4 to the first condensation tank and the second condensation tank for condensation and liquefaction; S7: After condensation in the first condensation tank, most of the acidic gas can be liquefied and discharged into the alkaline solution treatment pool in the treatment unit for absorption treatment, and the target gas product NF3 is condensed and liquefied in the second condensation tank and discharged into the NF3 collection tank; S8: First close the pressure reducing valves of the SF6 gas supply bottle and the NH3 gas supply bottle to maintain the stable operation of the coaxial DBD reactor; S9: After 10 minutes, the plasma power supply is turned off, and the background gas Ar is continuously introduced, so that the gas in the coaxial DBD reactor is introduced into the alkali solution treatment pool; S10: After 10 minutes, the condenser is turned off, the liquid in the NF3 collection tank is taken out and frozen, and the input of background gas Ar is turned off.

[0011] Compared with the prior art, the present invention provides a device and method for preparing NF3 by activating SF6 by dielectric barrier discharge, which has the following beneficial effects: 1. The device for preparing NF3 by activating SF6 by dielectric barrier discharge adopts dielectric barrier discharge technology, which can achieve efficient discharge at normal pressure or low pressure, generate a large number of high-energy electrons and active particles, and promote the progress of chemical reactions. At the same time, NH3 is used as a nitrogen source and fluorine-rich molecule SF6 is used as a fluorine source. Under the action of DBD plasma, SF6 is decomposed by bond breaking, so that NH3 reacts with low-fluorine sulfides produced by the decomposition of SF6 to synthesize the target product NF3.

[0012] 2. The method of preparing NF3 by activating SF6 with dielectric barrier discharge can effectively block the self-recovery reaction after SF6 decomposition by adding reducing gas NH3. At the same time, the addition of NH3 increases the density of active particles in the discharge area, making the SF6 bond breaking decomposition more thorough, which can significantly improve the SF6 degradation rate.

[0013] 3. The device for preparing NF3 by activating SF6 by dielectric barrier discharge, by placing the DBD reactor in a tubular furnace and performing a heating treatment, not only effectively avoids the solid S element generated by the reaction from clogging the gas pipe, but also the temperature increase can accelerate the chemical reaction and increase the synthesis rate of the target product NF3.

[0014] 4. The device for preparing NF3 by activating SF6 with dielectric barrier discharge uses a condenser to separate products. The condenser is divided into primary and secondary condensation. The primary condensation uses ethylene glycol to separate SF6 from other high-boiling-point gas products. The secondary condensation uses liquid nitrogen to liquefy NF3 and store it in a NF3 collection tank. By converting SF6 into NF3, SF6 can be used as a resource and environmental pollution can be reduced. By reacting SF6 with NH3 to generate NF3 electronic special gas, it can not only solve the greenhouse effect caused by SF6 discharge, but also use its added value as a resource to synthesize high-value NF3 electronic special gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the structure of a device for preparing NF3 by activating SF6 with dielectric barrier discharge proposed by the present invention; Figure 2 This is a schematic diagram of the gas supply unit structure of a device for preparing NF3 by activating SF6 with dielectric barrier discharge proposed by the present invention; Figure 3 This is a schematic diagram of the condensation unit structure of a device for preparing NF3 by activating SF6 with dielectric barrier discharge proposed by the present invention; Figure 4 This is a schematic diagram of the structure of a processing unit of a device for preparing NF3 by activating SF6 with dielectric barrier discharge proposed by the present invention; Figure 5 This is a schematic diagram of the structure of a coaxial DBD reactor of a device for preparing NF3 by activating SF6 with dielectric barrier discharge proposed by the present invention.

[0016] In the figure: 1 reaction unit, 101 coaxial DBD reactor, 1011 inner electrode tube, 1012 outer electrode tube, 1013 flange, 102 tubular furnace, 2 gas supply unit, 201 gas distributor, 202 SF6 gas supply bottle, 203 Ar gas supply bottle, 204 NH3 gas supply bottle, 205 pressure reducing valve, 206 electromagnetic flowmeter, 3 power supply unit, 4 condensing unit, 401, 402, 5 processing unit, 501 alkali solution treatment pool, 502 NF3 collection tank. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] See also Figure 1-5 A device for preparing NF3 by activating SF6 by dielectric barrier discharge includes a reaction unit 1, a gas supply unit 2 is arranged on the left side of the reaction unit 1, a power supply unit 3 is arranged on the top of the reaction unit 1, a condensation unit 4 is arranged on the right side of the reaction unit 1, and a processing unit 5 is arranged at the bottom of the condensation unit 4.

[0019] The reaction unit 1 is connected to the gas supply unit 2 through an air pipe, the reaction unit 1 is connected to the power supply unit 3 through an electrical connection, the reaction unit 1 is connected to the condensation unit 4 through an air pipe, and the condensation unit 4 is connected to the processing unit 5 through an air pipe.

[0020] The reaction unit 1 includes a coaxial DBD reactor 101, which is composed of an inner electrode tube 1011 and an outer electrode tube 1012. A flange 1013 is fixedly connected to the outer surface of the outer electrode tube 1012. A tubular furnace 102 is arranged on the outer surface of the coaxial DBD reactor 101. The inner electrode tube 1011 is composed of a quartz glass tube and a copper rod, and the outer electrode tube 1012 is made of quartz glass; The condensation unit 4 includes a first condensation tank 401 and a second condensation tank 402. The first condensation tank 401 and the second condensation tank 402 are connected by an air pipe. The left side of the first condensation tank 401 is connected to the reaction unit 1 by an air pipe. The first condensation tank 401 and the second condensation tank 402 are both provided with an exhaust port and a water outlet. The first condensation tank 401 is filled with an ethylene glycol mixed solution, and the second condensation tank 402 is filled with liquid nitrogen. The first condensation tank 401 and the second condensation tank 402 are both cooled by a condenser.

[0021] The gas supply unit 2 includes a gas distributor 201, the gas inlet of the gas distributor 201 is connected to the SF6 gas supply bottle 202, the Ar gas supply bottle 203 and the NH3 gas supply bottle 204 through a gas pipe, the outer surface of the gas pipe connecting the SF6 gas supply bottle 202, the Ar gas supply bottle 203, the NH3 gas supply bottle 204 and the gas distributor 201 is provided with a pressure reducing valve 205, and the outer surface of the gas pipe connecting the gas distributor 201 and the coaxial DBD reactor 101 is provided with an electromagnetic flowmeter 206.

[0022] The power supply unit 3 is a plasma power supply, and the discharge area on the outer surface of the inner electrode tube 1011 is wrapped by a metal mesh and is electrically connected to the plasma power supply.

[0023] The processing unit 5 consists of an alkali solution treatment tank 501 and an NF3 collection tank 502 . The top of the alkali solution treatment tank 501 is connected to the water outlet of the first condensation tank 401 by an air pipe, and the top of the NF3 collection tank 502 is connected to the water outlet of the second condensation tank 402 by an air pipe.

[0024] The temperature of liquid nitrogen in the second condensing tank 402 is -145°C, the temperature of the ethylene glycol-water mixed solution in the first condensing tank 401 is -75°C, and the temperature of the tubular furnace 102 is raised to about 100°C.

[0025] A method for preparing NF3 by activating SF6 by dielectric barrier discharge, the specific steps are: S1: SF6 gas supply bottle 202, Ar gas supply bottle 203, NH3 gas supply bottle 204 are connected to the gas distributor 201 through gas pipes, and the plasma power supply 301 is connected to the outer surface of the outer electrode tube 1012; S2: Connect the coaxial DBD reactor 101, the first condensation tank 401, the second condensation tank 402, the alkali solution treatment tank 501, and the NF3 collection tank 502; S3: First open the valves of the SF6 gas supply bottle 202, the Ar gas supply bottle 203, and the NH3 gas supply bottle 204, then open the pressure reducing valve 205 and the gas distributor 201, and introduce the gas according to the set ratio, which is 2% SF6, 1% NH3 and 97% Ar, and fully mix them in the gas distributor 210; S4: The mixed gas is sent to the discharge area of ​​the coaxial DBD reactor 101 for reaction, so as to achieve degradation of SF6 gas and synthesis of NF3 electronic special gas; S5: At the same time, the tubular furnace 102 heats the coaxial DBD reactor 101. After the temperature is raised to 100°C, the generated S element is sublimated and will not block the gas outlet. At the same time, the increase in reaction temperature can accelerate the chemical reaction and will not affect the subsequent separation of the target gas product. S6: sending the synthesized NF3 gas and other gaseous products such as SO2, SO2F2, SOF2, SOF4, SF4, SiH4, HF and SiF4 to the first condensation tank 401 and the second condensation tank 402 for condensation and liquefaction; S7: After condensation in the first condensation tank 401, most of the acidic gas can be liquefied and discharged into the alkaline solution treatment tank 501 in the processing unit 5 for absorption treatment, and the target gas product NF3 is condensed and liquefied in the second condensation tank 402 and discharged into the NF3 collection tank 502; S8: First close the pressure reducing valves 205 of the SF6 gas supply bottle 202 and the NH3 gas supply bottle 204 to keep the coaxial DBD reactor 101 running stably; S9: After 10 minutes, the plasma power supply is turned off, and the background gas Ar is continuously introduced, so that the gas in the coaxial DBD reactor 101 is introduced into the alkali solution treatment tank 501; S10: After 10 minutes, the condenser is closed, the liquid in the NF3 collection tank 502 is taken out and frozen for storage, and the input of the background gas Ar is closed.

[0026] By synthesizing NF3 through resource utilization of SF6, the value-added utilization of SF6 to synthesize NF3 electronic special gas is achieved, which solves the problems existing in the traditional method of synthesizing NF3, realizes the resource utilization of SF6, and reduces production costs and environmental impact.

[0027] By precisely controlling parameters such as discharge conditions and gas flow rate, the reaction process can be finely controlled.

[0028] The reactor adopts a coaxial double-layer dielectric barrier reactor, which can achieve SF6 degradation and synthesize NF3 electronic special gas. DBD plasma technology improves the speed and output of NF3 synthesis and improves production efficiency.

[0029] When NH3 participates in the degradation of SF6, it effectively improves the degradation rate and regulates the degradation products, producing some solid S single substance. When heated to 100°C in a tubular furnace, the S single substance can be sublimated, which will not block the gas outlet of the DBD reactor and will not affect the collection of subsequent gas products.

[0030] The degradation products are effectively separated by condensation. The condensation includes two-stage condensation. The unreacted SF6 and other gas products are liquefied by the first-stage condensation, while the NF3 and other non-condensable gases with lower boiling points are separated by liquid nitrogen in the second-stage condensation. The liquefied NF3 is discharged into the NF3 collection tank 502 through the water outlet.

[0031] Table 1:

[0032] Table 1 shows the degradation rate of SF6 and the yield of NF3 under the conditions of 2% SF6, 1% NH3, 97% Ar and a gas flow rate of 100 ml / min.

[0033] Table 2:

[0034] Table 2 shows the degradation rate of SF6 and the yield of NF3 when the ratio is 2% SF6, 2% NH3 and 96% Ar and the gas flow rate is 100 ml / min.

[0035] Table 3:

[0036] Table 3 shows the degradation rate of SF6 and the yield of NF3 when the ratio is 2% SF6, 3% NH3 and 95% Ar and the gas flow rate is 100 ml / min.

[0037] The above examples show that different NH3 volume fractions will lead to different SF6 degradation rates and NF3 synthesis rates, as analyzed below: When the NH3 volume fraction is low, NH3 produces fewer active particles in the plasma discharge area, and all the active particles produced are not enough to completely degrade SF6. When the NH3 volume fraction is high, there are too many NH3 molecules in the discharge area. When NH3 produces active particles, it absorbs a large amount of energy from the electric field and high-energy electrons, resulting in a reduction in the energy and high-energy particles that break the SF bond of SF6, so the degradation rate of SF6 is reduced. When the NH3 volume fraction is 2%, the most active substances are produced in the discharge area, which can fully collide with SF6, making its dissociation more thorough, and significantly improving the degradation rate of SF6. At the same time, NH3 reacts with the low-fluorine sulfide decomposed from SF6 to synthesize NF3 electronic special gas.

[0038] In summary, the device and method for preparing NF3 by activating SF6 by dielectric barrier discharge adopts dielectric barrier discharge technology, which can achieve efficient discharge at normal pressure or low pressure, generate a large number of high-energy electrons and active particles, and promote chemical reactions. At the same time, NH3 is used as a nitrogen source and fluorine-rich molecule SF6 is used as a fluorine source. Under the action of DBD plasma, SF6 is decomposed by bond breaking, so that NH3 reacts with the low-fluorine sulfide produced by the decomposition of SF6 to synthesize the target product NF3.

[0039] In addition, product separation is achieved by using a condenser. The condenser is divided into primary and secondary condensation. The primary condensation uses ethylene glycol to separate SF6 from other high-boiling-point gas products. The secondary condensation uses liquid nitrogen to liquefy NF3, which is then stored in a NF3 collection tank. By converting SF6 into NF3, SF6 can be utilized as a resource and environmental pollution can be reduced.

[0040] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for preparing NF3 by activating SF6 by dielectric barrier discharge, comprising a reaction unit (1), characterized in that: A gas supply unit (2) is arranged on the left side of the reaction unit (1), a power supply unit (3) is arranged on the top of the reaction unit (1), a condensation unit (4) is arranged on the right side of the reaction unit (1), and a processing unit (5) is arranged at the bottom of the condensation unit (4); The reaction unit (1) is connected to the gas supply unit (2) via an air pipe, the reaction unit (1) is connected to the power supply unit (3) via an electrical connection, the reaction unit (1) is connected to the condensation unit (4) via an air pipe, and the condensation unit (4) is connected to the processing unit (5) via an air pipe; The reaction unit (1) comprises a coaxial DBD reactor (101), the coaxial DBD reactor (101) comprising an inner electrode tube (1011) and an outer electrode tube (1012), a flange (1013) being fixedly connected to the outer surface of the outer electrode tube (1012), and a tubular furnace (102) being arranged on the outer surface of the coaxial DBD reactor (101); The inner electrode tube (1011) is composed of a quartz glass tube and a copper rod, and the outer electrode tube (1012) is made of quartz glass; The condensation unit (4) comprises a first condensation tank (401) and a second condensation tank (402), the first condensation tank (401) and the second condensation tank (402) are connected via an air pipe, the left side of the first condensation tank (401) is connected to the reaction unit (1) via an air pipe, the first condensation tank (401) and the second condensation tank (402) are both provided with an exhaust port and a water outlet, the first condensation tank (401) is filled with an ethylene glycol mixed solution, the second condensation tank (402) is filled with liquid nitrogen, and the first condensation tank (401) and the second condensation tank (402) are both cooled by a condenser.

2. The device for preparing NF3 by dielectric barrier discharge activation of SF6 according to claim 1, characterized in that: The gas supply unit (2) comprises a gas distributor (201); a gas inlet of the gas distributor (201) is connected to an SF6 gas supply bottle (202), an Ar gas supply bottle (203) and an NH3 gas supply bottle (204) via a gas pipe; a pressure reducing valve (205) is arranged on the outer surface of the gas pipe connecting the SF6 gas supply bottle (202), the Ar gas supply bottle (203) and the NH3 gas supply bottle (204) to the gas distributor (201); and an electromagnetic flowmeter (206) is arranged on the outer surface of the gas pipe connecting the gas distributor (201) and the coaxial DBD reactor (101).

3. The device for preparing NF3 by activating SF6 by dielectric barrier discharge according to claim 1, characterized in that: The power supply unit (3) is a plasma power supply, and the discharge area on the outer surface of the inner electrode tube (1011) is wrapped by a metal mesh and is electrically connected to the plasma power supply.

4. The device for preparing NF3 by activating SF6 by dielectric barrier discharge according to claim 1, characterized in that: The processing unit (5) consists of an alkali solution treatment tank (501) and an NF3 collection tank (502); the top of the alkali solution treatment tank (501) is connected to the water outlet of the first condensation tank (401) by an air pipe, and the top of the NF3 collection tank (502) is connected to the water outlet of the second condensation tank (402) by an air pipe.

5. The device for preparing NF3 by activating SF6 by dielectric barrier discharge according to claim 1, characterized in that: The temperature of liquid nitrogen inside the second condensing tank (402) is -145°C, and the temperature of the ethylene glycol-water mixed solution inside the first condensing tank (401) is -75°C.

6. A method for preparing NF3 by activating SF6 with dielectric barrier discharge according to any one of claims 1 to 5, characterized in that: The specific steps are: S1: The SF6 gas supply bottle (202), the Ar gas supply bottle (203), and the NH3 gas supply bottle (204) are connected to the gas distribution device (201) through a gas pipe, and the plasma power supply (301) is connected to the outer surface of the outer electrode tube (1012); S2: connecting the coaxial DBD reactor (101), the first condensation tank (401), the second condensation tank (402), the alkali solution treatment tank (501), and the NF3 collection tank (502); S3: First, open the valves of the SF6 gas supply bottle (202), the Ar gas supply bottle (203), and the NH3 gas supply bottle (204), then open the pressure reducing valve (205) and the gas distributor (201), introduce the gas according to the set ratio, and fully mix them in the gas distributor (210); S4: sending the mixed gas into the discharge region of the coaxial DBD reactor (101) for reaction, thereby achieving degradation of the SF6 gas and synthesis of the NF3 electronic special gas; S5: At the same time, the tubular furnace (102) heats the coaxial DBD reactor (101), and after the temperature is raised to 100° C., the S single substance generated by the reaction can be sublimated; S6: sending the synthesized NF3 gas and other gaseous products such as SO2, SO2F2, SOF2, SOF4, SF4, SiH4, HF and SiF4 to the first condensation tank (401) and the second condensation tank (402) for condensation and liquefaction; S7: After being condensed in the first condensation tank (401), most of the acidic gas can be liquefied and discharged into the alkaline solution treatment tank (501) in the treatment unit (5) for absorption treatment, and the target gas product NF3 is condensed and liquefied in the second condensation tank (402) and discharged into the NF3 collection tank (502); S8: First, close the pressure reducing valves (205) of the SF6 gas supply bottle (202) and the NH3 gas supply bottle (204) to maintain stable operation of the coaxial DBD reactor (101); S9: After 10 minutes, the plasma power supply is turned off, and background gas Ar is continuously introduced, so that the gas in the coaxial DBD reactor (101) is introduced into the alkali solution treatment pool (501); S10: After 10 minutes, the condenser is turned off, the liquid in the NF3 collection tank (502) is taken out and frozen, and the input of background gas Ar is turned off.

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