Fluorine-containing gas degradation device and method based on inductively coupled thermal plasma

Abstract

The invention discloses a fluorine-containing gas degradation device and method based on inductively coupled thermal plasma. In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, an air intake control system controls the flow rates of carrier gas, cooling gas, fluorine-containing gas and active gas respectively; an inductively coupled plasma reactor generates and constrains a thermal plasma region, and a cavity vibration generator is fixed on the outer wall of the reaction chamber to prevent solid powder from adhering; a tail gas treatment system uses a conical powder collector to process solid products, and a spray tower to process acidic gas products, and discharges after being tested to meet standards. The device uses a high-frequency AC power supply and an induction coil to generate inductively coupled thermal plasma in the reaction chamber, and the fluorine-containing gas is completely decomposed and reacts with the active gas under the action of local high temperature, thereby suppressing the self-recovery characteristics of the fluorine-containing gas.

Description

Technical Field

[0001] The invention belongs to the technical field of gas degradation, and in particular to a fluorine-containing gas degradation device and method based on inductively coupled thermal plasma. Background Art

[0002] SF 6 and CF 4 Fluorine-containing gases such as SF6 and SF7 are currently widely used in the power switch industry due to their stable physical and chemical properties and excellent electrical insulation performance. However, due to their strong greenhouse effect, fluorine-containing gases have a great impact on the environment. However, no suitable high-performance alternative gases have been found so far, and they are still widely used in power systems. 6 Fluorine-containing gases such as fluorine have strong self-recovery properties and are difficult to be completely degraded. Therefore, it is of great significance to find a method that can efficiently degrade fluorine-containing gases.

[0003] In recent years, plasma waste gas treatment technology has received widespread attention and research. Compared with traditional methods such as pyrolysis and chemical catalysis, plasma technology has the characteristics of high degradation rate, high energy efficiency and simple operation.

[0004] Cold plasma technology has been used to degrade SF 6 For example, Kabouzi et al. studied the effect of SF on the performance of fluorine-containing gases under different concentration ranges and microwave powers. 6 Shih et al. used a radio frequency plasma method to propose a set of low-concentration SF cascade etching equipment that can be applied to the semiconductor industry. 6 Exhaust gas treatment device, Zhang Xiaoxing et al. studied the effects of different active gases and filling media on SF 6 There are also precedents for using thermal plasma in research related to the degradation of fluorine-containing gases, such as the thermal plasma-based sulfur hexafluoride degradation device studied by Sun Hao and others from Xi'an Jiaotong University.

[0005] However, there are many problems with these cold plasma and hot plasma devices. For example, the cold plasma method can only process low-concentration SF 6 A higher degradation rate is obtained when treating waste gas, and when treating high-concentration SF 6When it comes to waste gas, it needs to be diluted before treatment; and the processing capacity of cold plasma is low, usually the gas flow rate is not higher than 1L / min; and cold plasma cannot completely decompose fluorine-containing gases due to its low discharge power. The thermal plasma degradation device solves the above problems to a certain extent, but the violent arc will cause serious ablation of the electrode, the working life of the electrode is not long, and the cost of replacing the electrode is high, and the equipment maintenance is frequent. The present invention aims to solve the above problems.

[0006] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention proposes a fluorine-containing gas degradation device and method based on inductively coupled thermal plasma. The processing capacity is improved by using thermal plasma, and the cavity wall is vibrated by a vibration system to avoid the adhesion of solid products. At the same time, the cavity material resistant to hydrogen fluoride corrosion is selected, which has good practical value.

[0008] The object of the present invention is achieved through the following technical scheme: a fluorine-containing gas degradation device based on inductively coupled thermal plasma comprises:

[0009] An intake control system comprising:

[0010] The carrier gas and cooling gas input circuit comprises an Ar gas source, a gas valve and two parallel mass flow meters connected in sequence, wherein one mass flow meter, the gas valve and the Ar gas source constitute a working state carrier gas input circuit providing a working state carrier gas Ar flow rate Q1, and the other mass flow meter, the gas valve and the Ar gas source constitute a cooling gas Ar input circuit providing a cooling gas Ar flow rate Q2,

[0011] The reaction gas input circuit includes a reaction gas source, a gas valve and a mass flow meter connected in sequence to provide an active gas flow Q3.

[0012] A fluorine-containing gas input circuit, comprising a fluorine-containing gas source, a gas valve and a mass flow meter connected in sequence to provide a fluorine-containing gas flow rate Q4;

[0013] An inductively coupled thermal plasma generator comprising,

[0014] a closed housing including a reaction chamber,

[0015] A concentric ceramic tube is arranged in the closed shell, a swirl ring is embedded in the concentric ceramic tube, the swirl ring includes a rotating gas path that causes the gas to generate axial and tangential component velocities, the input gas flow field converges to the center of the ring through the rotating gas path, the innermost layer of the concentric ceramic tube is connected to the working state carrier gas input line to controllably provide the working state carrier gas Ar flow rate Q1, the middle layer of the swirl ring is connected to the reaction gas input line and the fluorine-containing gas input line to controllably provide the active gas flow rate Q3 and the fluorine-containing gas flow rate Q4, the outer layer is connected to the cooling gas Ar input line to controllably provide the cooling gas Ar flow rate Q2,

[0016] A coil is disposed in the closed shell and connected to a high-frequency power source outside the closed shell to generate coupled thermal plasma.

[0017] A cavity vibration generator is arranged on the outer wall of the closed shell;

[0018] The harmless treatment system comprises:

[0019] The conical powder collector is located at the lower end of the reaction chamber. Under the action of the chamber vibration generator, the solid product is difficult to collect at the bottom of the conical powder collector.

[0020] An alkali liquid spray tower is connected to the gas product outlet of the reaction chamber, and comprises:

[0021] The tower contains the alkali solution.

[0022] The mortar pump circulates the alkali solution from the lower part of the tower to the upper part.

[0023] At least one packing layer is stacked in the tower body at intervals.

[0024] A nozzle is connected to the mortar pump and is arranged above the packing layer. The acidic gas product is adsorbed by the packing layer and reacts with the alkaline mist at the nozzle.

[0025] The waste gas detection device is connected to the sampling ports arranged before and after the alkali solution spray tower to sample and detect the waste gas discharged from the alkali solution spray tower.

[0026] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the flow rate of the cooling gas Ar is 50 L / min, and the flow rate of the carrier gas Ar is 30 L / min.

[0027] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, when the active gas and the fluorine-containing gas are H 2 and SF 6 When the ratio is 4:1, when the active gas and the fluorine-containing gas are H 2 and CF 4 The ratio is 3:1.

[0028] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the concentric ceramic tube is a three-layer concentric ceramic tube, and the diameter of the outermost ceramic tube is 5 cm.

[0029] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the voltage of the high-frequency power supply is 5 kV, the current is 6 A, and the operating frequency is 3 MHz.

[0030] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the conductor of the coil is a hollow water-cooled conductor.

[0031] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the coil is provided with an electromagnetic shield for electromagnetic shielding.

[0032] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the alkali solution spray tower uses 5% Ca(OH) 2 Alkali is used to absorb acidic gas products.

[0033] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the waste gas detection device includes an X-ray diffraction analyzer, a chromatographic analyzer and a spectroscopic analyzer.

[0034] The degradation method of the fluorine-containing gas degradation device based on inductively coupled thermal plasma comprises the following steps:

[0035] Ar is introduced into the inductively coupled thermal plasma generator as carrier gas and cooling gas, and a high-frequency power source acts on the coil to generate an alternating magnetic field to generate thermal plasma;

[0036] A predetermined ratio of fluorine-containing gas and reaction gas is introduced, and the free radicals generated under the action of thermal plasma are degraded into solid products and gas products, wherein the thermal plasma reaction temperature is 6000K-15000K;

[0037] The gaseous product after the reaction is passed into the alkali liquid spray tower to be discharged after absorbing harmful gases, and the solid product is discharged through the solid product outlet.

[0038] Compared with the prior art, the present invention has the following advantages: the present invention adopts thermal plasma degradation technology, the reaction temperature is higher, the degradation is more thorough, and the processing capacity is greater; the inductively coupled thermal plasma device is used as the plasma generation source, which effectively solves the ablation problem of the solid electrode and greatly enhances the service life of the generation device; the cavity vibration device is added to effectively prevent the solid powder generated during the reaction from adhering to the inner wall of the reaction wall, which is beneficial to the later collection and treatment of the solid product; the Hastelloy alloy lining is added to make the reaction cavity more resistant to hydrogen fluoride corrosion and extend the service life of the cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0040] In the attached picture:

[0041] Figure 1 is a schematic structural diagram of a fluorine-containing gas degradation device based on inductively coupled thermal plasma according to one embodiment of the present invention;

[0042] Figure 2 It is a schematic structural diagram of an inductively coupled thermal plasma generator of a fluorine-containing gas degradation device based on inductively coupled thermal plasma according to an embodiment of the present invention.

[0043] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0044] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0045] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.

[0046] To facilitate understanding of the embodiments of the present invention, further explanation will be given below by taking specific embodiments as examples in conjunction with the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0047] For a better understanding, Figure 1 to Figure 2 As shown, the fluorine-containing gas degradation device based on inductively coupled thermal plasma includes:

[0048] An intake control system comprising:

[0049] The carrier gas and cooling gas input circuit comprises an Ar gas source, a gas valve 1 and two parallel mass flow meters connected in sequence, wherein one mass flow meter, the gas valve 1 and the Ar gas source constitute a working state carrier gas input circuit providing a working state carrier gas Ar flow rate Q1, and the other mass flow meter, the gas valve 1 and the Ar gas source constitute a cooling gas Ar input circuit providing a cooling gas Ar flow rate Q2,

[0050] The reaction gas input circuit includes a reaction gas source, a gas valve 1 and a mass flow meter connected in sequence to provide an active gas flow Q3.

[0051] A fluorine-containing gas input circuit, comprising a fluorine-containing gas source, a gas valve 1 and a mass flow meter connected in sequence to provide a fluorine-containing gas flow rate Q4;

[0052] An inductively coupled thermal plasma generator 3, comprising:

[0053] a closed housing including a reaction chamber,

[0054] The concentric ceramic tube 3.4 is arranged in the closed shell, and the swirl ring 3.1 is embedded in the concentric ceramic tube 3.4. The swirl ring 3.1 includes a rotating gas path that causes the gas to generate axial and tangential component velocities. The input gas flow field converges to the center of the ring through the rotating gas path. The innermost layer of the concentric ceramic tube 3.4 is connected to the working state carrier gas input circuit to controllably provide the working state carrier gas Ar flow rate Q1. The swirl ring 3.1 of the middle layer is connected to the reaction gas input circuit and the fluorine-containing gas input circuit to controllably provide the active gas flow rate Q3 and the fluorine-containing gas flow rate Q4. The outer layer is connected to the cooling gas Ar input circuit to controllably provide the cooling gas Ar flow rate Q2.

[0055] The coil 3.2 is arranged in the closed shell and connected to the high-frequency power source 4 outside the closed shell to generate coupled thermal plasma.

[0056] A cavity vibration generator 5, which is arranged on the outer wall of the closed shell;

[0057] The harmless treatment system comprises:

[0058] The conical powder collector is located at the lower end of the reaction chamber. Under the action of the chamber vibration generator 5, the solid product is difficult to collect at the bottom of the conical powder collector.

[0059] The alkali liquid spray tower 8 is connected to the gas product outlet 7 of the reaction chamber, and comprises:

[0060] The tower contains the alkali solution.

[0061] The mortar pump 8.1 circulates the alkali solution from the lower part of the tower to the upper part.

[0062] At least one packing layer 8.3 is stacked in the tower body at intervals.

[0063] The nozzle 8.2 is connected to the mortar pump 8.1 and is arranged above the packing layer 8.3. The acidic gas product is adsorbed by the packing layer 8.3 and reacts with the alkaline mist at the nozzle.

[0064] The waste gas detection device is connected to the sampling ports arranged before and after the alkali solution spray tower 8 to sample and detect the waste gas discharged from the alkali solution spray tower 8.

[0065] In a preferred embodiment of the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the flow rate of the cooling gas Ar is 50 L / min, and the flow rate of the carrier gas Ar is 30 L / min.

[0066] In a preferred embodiment of the fluorine-containing gas degradation device based on inductively coupled thermal plasma, when the active gas and the fluorine-containing gas are H 2 and SF 6 When the ratio is 4:1, when the active gas and the fluorine-containing gas are H 2 and CF 4 The ratio is 3:1.

[0067] In a preferred embodiment of the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the concentric ceramic tube 3.4 is a three-layer concentric ceramic tube 3.4, and the diameter of the outermost ceramic tube is 5 cm.

[0068] In a preferred embodiment of the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the voltage of the high-frequency power supply 4 is 5 kV, the current is 6 A, and the operating frequency is 3 MHz.

[0069] In a preferred embodiment of the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the conductor of the coil 3.2 is a hollow water-cooled conductor.

[0070] In a preferred embodiment of the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the coil 3.2 is provided with an electromagnetic shield 3.5 for electromagnetic shielding.

[0071] In the preferred embodiment of the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the alkali solution spray tower 8 uses 5% Ca(OH) 2 Alkali is used to absorb acidic gas products.

[0072] In a preferred embodiment of the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the exhaust gas detection device includes an X-ray diffraction analyzer, a chromatographic analyzer and a spectroscopic analyzer.

[0073] The degradation method of the fluorine-containing gas degradation device based on inductively coupled thermal plasma comprises the following steps:

[0074] Ar is introduced into the inductively coupled thermal plasma generator 3 as a carrier gas and cooling gas, and a high frequency power supply 4 acts on the coil 3.2 to generate an alternating magnetic field to generate thermal plasma;

[0075] A predetermined ratio of fluorine-containing gas and reaction gas is introduced, and the free radicals generated under the action of thermal plasma are degraded into solid products and gas products, wherein the thermal plasma reaction temperature is 6000K-15000K;

[0076] The gaseous product after the reaction is passed into the alkali solution spray tower 8 to be discharged after absorbing harmful gases, and the solid product is discharged through the solid product outlet 6.

[0077] A solid product outlet 6 for discharging solid products is provided at the bottom of the conical powder collector.

[0078] In one embodiment, the fluorine-containing gas degradation device based on inductively coupled thermal plasma includes:

[0079] An intake control system comprising:

[0080] The carrier gas and cooling gas input circuit includes an Ar gas source, a gas valve 1, and two parallel Ar mass flow meters connected in sequence;

[0081] Reagent gas input line, where the reactant gas can be H 2 or 2 or other active gases, including a reaction gas source, a gas valve 1 and a corresponding mass flow meter connected in sequence;

[0082] A fluorine-containing gas input circuit, comprising a fluorine-containing gas source, a gas valve 1 and a mass flow meter for the fluorine-containing gas connected in sequence;

[0083] An inductively coupled thermal plasma generator 3, comprising:

[0084] A closed shell, comprising a reaction chamber and a cavity vibration generator 5, wherein the reaction chamber is connected to the air intake control system and receives carrier gas Ar, cooling gas Ar, reaction gas and fluorine-containing gas through three-layer concentric ceramic tubes 3.4 in a predetermined proportion; the cavity vibration generator 5 is fixed on the outer surface of the cavity to generate stable vibration;

[0085] A high-frequency AC power supply provides a high-frequency electromagnetic signal to generate coupled thermal plasma in the ceramic tube;

[0086] Hollow water-cooled induction coil and coil water cooling device, the coil 3.2 is connected to the high-frequency power supply 4, surrounded by the outer wall of the concentric ceramic tube, used to generate a high-frequency magnetic field under a high-frequency electrical signal, and cooling water flows through the hollow inside of the coil 3.2 to cool the coil 3.2;

[0087] The ceramic gas inlet is a three-layer concentric ceramic tube 3.4, one end of which is connected to the closed shell, and the other end is connected to the carrier gas channel, the reaction gas and fluorine-containing gas channel, and the cooling gas channel, which is responsible for providing a place for the generation of high-frequency inductively coupled plasma and restricting the size of the plasma torch 3.3;

[0088] The harmless treatment system comprises:

[0089] Conical powder collector, under the action of the cavity vibration generator 5, the solid product is difficult to adhere to the reaction chamber wall and is collected at the bottom of the conical cavity;

[0090] Alkali liquid spray tower 8, the alkali liquid spray tower 8 includes a mortar pump 8.1 for circulating and extracting alkali liquid, which is connected to the reaction chamber, and the acidic gas product is adsorbed by the packing layer 8.3 and reacts with the alkali mist at the nozzle, wherein the uppermost packing layer is used to absorb excess alkali mist;

[0091] The waste gas detection device is provided with sampling ports before and after the alkali solution spray tower 8 to sample and detect the waste gas discharged from the alkali solution spray tower 8.

[0092] The working process of the fluorine-containing gas degradation device based on inductively coupled thermal plasma is as follows: first, Ar is introduced as a carrier gas and cooling gas, and then the high-frequency power supply 4 and the induction coil are used to generate inductively coupled thermal plasma in the reaction chamber, and then the fluorine-containing gas and the active gas to be reacted are introduced, and the local high temperature of the thermal plasma is used to completely decompose the fluorine-containing gas. Furthermore, the free radicals generated after the decomposition of the fluorine-containing gas and the active gas combine with each other to form degradation products to inhibit the self-recovery reaction of the fluorine-containing gas. Finally, the obtained solid and gas degradation products are collected and processed, and discharged after testing to meet the standards.

[0093] The fluorine-containing gas and the active gas are SF 6 With H 2 The reaction principle is as follows:

[0094] SF 6 +3H 2 →S+6HF.

[0095] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the flow rate of the cooling gas Ar is 50 L / min, and the flow rate of the carrier gas Ar is 30 L / min. 2 and SF 6When the active gas and the fluorine-containing gas are H 2 and CF 4 The ratio is about 3:1.

[0096] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the positive and negative electrodes of the high-frequency AC power supply are connected to the induction coil 3.2, and its output frequency and output power are adjustable.

[0097] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the ceramic tube is a three-layer concentric ceramic tube 3.4, and the diameter of the outermost ceramic tube is 5 cm; the induction coil is wound around the concentric ceramic tube for 4 turns to transmit power to the plasma.

[0098] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the inner wall of the reaction chamber is lined with 6mm C-276, which has a melting point of 1325-1370°C and a high nickel-based content, and is the preferred material for high-temperature and highly corrosive media.

[0099] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the alkali solution spray tower 8 uses 5% Ca(OH) 2 Lye.

[0100] In the fluorine-containing gas degradation device based on inductively coupled thermal plasma, the cavity vibration generator 5 is a pneumatic vibrator fixed to the outer wall of the reaction chamber, and separates the solid products attached to the inner wall by rapid vibration, and its vibration amplitude and frequency are adjustable.

[0101] In one embodiment, the fluorine-containing gas degradation device based on inductively coupled thermal plasma includes an intake control system, an inductively coupled thermal plasma generator and a harmless treatment system. The intake control system includes input lines for four gases: fluorine-containing gas, reaction gas, carrier gas and cooling gas. The input lines of each gas include three parts: a respective gas source, a gas valve 1 and a gas mass flow meter 2. The gas flow controlled by the mass flow meter 2 can be adjusted. In a typical working state, the carrier gas Ar flow Q1 is 30 L / min, the cooling gas Ar flow Q2 is 50 L / min, the reactive gas flow Q3 and the fluorine-containing gas flow Q4 are in H 2 and SF 6 For example, they are 40L / min and 10L / min respectively.

[0102] In one embodiment, the inductively coupled thermal plasma generator 3 includes a high-frequency AC power supply 4. The positive and negative electrodes of the high-frequency AC source 4 are respectively connected to the two ends of the coil 3.2 to provide a high-frequency AC signal to the coil. The typical working state is a voltage of 5kV, a current of 6A, and an operating frequency of 3MHz. In the inductively coupled thermal plasma generator 3, the swirl ring 3.1 contains a rotating gas path inside, which can make the gas produce axial and tangential component velocities, so that the gas flow field of the input gas converges to the center of the ring. The function of the induction coil 3.2 is to provide a high-frequency magnetic field and provide energy for the plasma. The electromagnetic shield 3.5 electromagnetically shields the coil to prevent the high-frequency magnetic field from affecting the outside world. The main function of the three-layer concentric ceramic tube 3.4 is to disperse the intake air and converge the plasma torch 3.3. The inner wall of the reaction chamber is lined with 6mm C-276, which is the preferred material for high-temperature and highly corrosive media.

[0103] In one embodiment, the harmless treatment system includes a cavity vibration generator 5, a solid product outlet 6, a gas product outlet 7, an alkali liquid spray tower 8, and a waste gas and waste residue detection device. The solid product is collected using a conical powder collector. The cavity vibration generator 5 causes the cavity to vibrate rapidly to prevent the solid product from adhering to the inner wall of the cavity. Under the action of vibration and gravity, the solid product is gathered at the solid product outlet 6 for easy collection. The collected solid product can be further recycled and processed; the gas product outlet 7 can directly sample the post-reaction gas. At the same time, the gas product outlet 7 is connected to the alkali liquid spray tower 8. The waste gas generated by the reaction is collected or discharged from the tail gas outlet 8.5 after being treated by the alkali liquid spray tower. The alkali liquid spray tower 8 uses 5% Ca(OH) 2 Alkaline solution 8.4 is pumped by mortar pump 8.1 to the alkali mist nozzle 8.2 for spraying. The main material of the packing layer 8.3 is PE block packing, so that the sprayed alkali mist and alkali solution are fully absorbed by the gas product. The CaF 2 The precipitate can also be recycled; the waste gas detection device can use a chromatograph and a spectrometer for detection, and the waste gas can be directly discharged into the atmosphere after being tested and found to meet the standards; the waste residue detection device can use an X-ray diffraction analyzer for detection.

[0104] In one embodiment, the wire of the coil is a hollow water-cooled wire. The wire will generate a lot of heat under the action of high-frequency AC power. Due to the skin effect, the wire current mainly passes through the outer wall of the wire. The hollow interior does not affect the use of the wire. At the same time, the hollow water cooling makes it easier to dissipate heat from the wire and increases its service life.

[0105] In one embodiment, the diameter of the three-layer concentric ceramic tube should be selected within a suitable range, neither too large nor too small. A too large diameter will lead to unfocused magnetic field and energy dissipation, affecting the energy efficiency of the inductively coupled thermal plasma as well as the arc power and temperature. A too small diameter will lead to a significant reduction in gas flow and a slowdown in product processing rate.

[0106] In one embodiment, the pneumatic vibrator is fixed on the outer wall of the reaction chamber. Before collecting the solid product, the pneumatic vibrator is started to collect the solid product attached to the inner wall of the reaction chamber to the solid product outlet 6 through vibration and gravity, and then the solid product is collected using a cloth bag.

[0107] In one embodiment, Ar is used as a carrier gas and a cooling gas. Ar as a carrier gas makes arcing more stable and requires less power to maintain arc discharge. Ar as an inert gas does not react with the fluorine-containing gas to generate other byproducts. 2 As a reaction gas, it reacts with fluorine-containing gases to generate only HF and the corresponding solid element, which is more convenient for harmless treatment.

[0108] Optionally, N2 can be used as cooling gas and carrier gas. 2 Nitrogen is cheaper and more readily available, but N and F will combine to form NF during the cooling process. 3 , which is also a greenhouse gas.

[0109] Optionally, the reaction gas can be an oxygen-containing gas. The principle of its degradation of fluorine-containing gas is slightly different from that of hydrogen. During the cooling process, O radicals combine with S or C to generate SO x F y , SO x or CO x F y , CO x etc., in order to inhibit SF 6 The self-recovery characteristics of the catalyst and the advantage of using oxygen is that no solid products are generated.

[0110] In one embodiment, the degradation method of the fluorine-containing gas degradation device based on inductively coupled thermal plasma includes:

[0111] Ar is used as carrier gas and cooling gas to pass into the inductively coupled thermal plasma generator, and the high-frequency power source acts on the coupled inductor to generate an alternating magnetic field to generate plasma and provide energy;

[0112] A predetermined ratio of fluorine-containing gas and reaction gas is introduced, and the free radicals generated under the action of thermal plasma combine with each other to inhibit the self-recovery characteristics of sulfur hexafluoride. The final product can be in the form of solid or gas according to the different reaction gases introduced, wherein the reaction temperature in the arc plasma region is about 6000K-15000K;

[0113] The gaseous product after the reaction is passed into the alkali liquid spray tower, where it is discharged after absorbing harmful gases. After passing the inspection, it can be directly discharged into the atmosphere. The solid product is discharged and inspected through the solid product outlet, which is convenient for recycling.

[0114] The carrier gas and cooling gas can be Ar or N 2 , the active gas may be H 2 or 2 , the fluorine-containing gas includes SF 6 and CF 4 .

[0115] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific embodiments and application fields, and the above specific embodiments are only illustrative and instructive, rather than restrictive. A person of ordinary skill in the art can also make many forms under the guidance of this specification and without departing from the scope of protection of the claims of the present invention, all of which belong to the protection of the present invention.

Claims

1. A fluorine-containing gas degradation device based on inductively coupled thermal plasma, comprising: An intake control system comprising: A carrier gas and cooling gas input circuit, comprising an Ar gas source, a gas valve and two parallel mass flow meters connected in sequence, wherein one mass flow meter, the gas valve and the Ar gas source constitute a working state carrier gas input circuit providing a working state carrier gas Ar flow rate Q1, and another mass flow meter, the gas valve and the Ar gas source constitute a cooling gas Ar input circuit providing a cooling gas Ar flow rate Q2; A reaction gas input circuit, which includes a reaction gas source, a gas valve and a mass flow meter connected in sequence to provide an active gas flow Q3; A fluorine-containing gas input circuit, comprising a fluorine-containing gas source, a gas valve and a mass flow meter connected in sequence to provide a fluorine-containing gas flow rate Q4; An inductively coupled thermal plasma generator, comprising: a closed housing including a reaction chamber; A concentric ceramic tube, which is arranged in the closed shell, and a swirl ring is embedded in the concentric ceramic tube, the swirl ring includes a rotating gas path that causes the gas to generate axial and tangential component velocities, and the input gas flow field converges to the center of the ring through the rotating gas path, the innermost layer of the concentric ceramic tube is connected to the working state carrier gas input circuit to controllably provide the working state carrier gas Ar flow rate Q1, the middle layer of the swirl ring is connected to the reaction gas input circuit and the fluorine-containing gas input circuit to controllably provide the active gas flow rate Q3 and the fluorine-containing gas flow rate Q4, and the outer layer is connected to the cooling gas Ar input circuit to controllably provide the cooling gas Ar flow rate Q2; A coil, which is arranged in the closed shell and connected to a high-frequency power source outside the closed shell to generate coupled thermal plasma; A cavity vibration generator is arranged on the outer wall of the closed shell; The harmless treatment system includes: The conical powder collector is located at the lower end of the reaction chamber. Under the action of the chamber vibration generator, the solid product is difficult to collect at the bottom of the conical powder collector; An alkali liquid spray tower, which is connected to the gas product outlet of the reaction chamber, comprises: a tower body, which contains the alkali solution; A mortar pump, which circulates the alkali solution from the lower part of the tower to the upper part; At least one packing layer is stacked in the tower body at intervals; A nozzle, which is connected to the mortar pump and is arranged above the packing layer, and the acidic gas product is adsorbed by the packing layer and reacts with the alkaline mist at the nozzle; The waste gas detection device is connected to the sampling ports arranged before and after the alkali solution spray tower to sample and detect the waste gas discharged from the alkali solution spray tower.

2. The fluorine-containing gas degradation device based on inductively coupled thermal plasma according to claim 1, wherein: The flow rate of the cooling gas Ar was 50 L / min, and the flow rate of the carrier gas Ar was 30 L / min.

3. The fluorine-containing gas degradation device based on inductively coupled thermal plasma according to claim 1, wherein: When the active gas and the fluorine-containing gas are H2 and SF6, the ratio thereof is 4:1, and when the active gas and the fluorine-containing gas are H2 and CF4, the ratio thereof is 3:

1.

4. The fluorine-containing gas degradation device based on inductively coupled thermal plasma according to claim 1, wherein: The concentric ceramic tube is a three-layer concentric ceramic tube, and the diameter of the outermost ceramic tube is 5 cm.

5. The fluorine-containing gas degradation device based on inductively coupled thermal plasma according to claim 1, wherein: The voltage of the high-frequency power supply is 5 kV, the current is 6 A, and the operating frequency is 3 MHz.

6. The fluorine-containing gas degradation device based on inductively coupled thermal plasma according to claim 1, wherein: The conductor of the coil is a hollow water-cooled conductor.

7. The fluorine-containing gas degradation device based on inductively coupled thermal plasma according to claim 1, wherein: The coil is provided with an electromagnetic protection cover for electromagnetic shielding.

8. The fluorine-containing gas degradation device based on inductively coupled thermal plasma according to claim 1, wherein: The alkali solution spray tower uses 5% Ca(OH)2 alkali solution to absorb acidic gas products.

9. The fluorine-containing gas degradation device based on inductively coupled thermal plasma according to claim 1, wherein: The exhaust gas detection device includes an X-ray diffraction analyzer, a chromatographic analyzer and a spectroscopic analyzer.

10. The degradation method of the fluorine-containing gas degradation device based on inductively coupled thermal plasma according to any one of claims 1 to 9, comprising the following steps: Ar is introduced into the inductively coupled thermal plasma generator as carrier gas and cooling gas, and a high-frequency power source acts on the coil to generate an alternating magnetic field to generate thermal plasma; A predetermined ratio of fluorine-containing gas and reaction gas is introduced, and the free radicals generated under the action of thermal plasma are degraded into solid products and gas products, wherein the thermal plasma reaction temperature is 6000K-15000K; The gaseous product after the reaction is passed into the alkali liquid spray tower to be discharged after absorbing harmful gases, and the solid product is discharged through the solid product outlet.

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