SF6 dynamic degradation device

Abstract

The invention relates to the technical field of sulfur hexafluoride (SF6) gas thermocatalytic degradation, and discloses an SF6 dynamic degradation device which comprises a gas feeding unit, a reaction unit and a product post-treatment unit, and the reaction unit is a vertical reaction tube arranged vertically. A catalyst supporting component is arranged in the reactor, the catalyst supporting component is annular, and holes for gas to penetrate through are formed in the catalyst supporting component. According to the invention, the gas feeding unit, the reaction unit and the product post-treatment unit are integrated, and the reaction tube is arranged to be vertical, so that gas can uniformly move downwards under the assistance of gravity, the catalytic efficiency is further improved, the integrality of the device is improved due to high integration, and the overall movement and convenient use of the device are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of thermal catalytic degradation of sulfur hexafluoride (SF6) gas, and in particular to a SF6 dynamic degradation device. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] SF6 is a synthetic gas. The central sulfur atom is stably connected to the six surrounding fluorine atoms by covalent bonds, forming an octahedral configuration. It is colorless, odorless, non-toxic, non-flammable, and slightly soluble in water. It has very stable chemical properties and strong electron affinity. It can undergo a self-recovery process after bond breaking, so it has excellent insulation and arc extinguishing properties. However, due to its high temperature at 915-960cm -1 The efficient absorption of infrared radiation in this band will lead to a serious greenhouse effect. Its global warming potential (GWP) is 23,500 times that of CO2, far exceeding other greenhouse gases. SF6 can exist stably in the atmosphere for up to 3,200 years and only slowly decomposes under ultraviolet light. As the non-CO2 gas with the strongest greenhouse effect and a very long atmospheric life, how to efficiently, environmentally friendly and scale-up the large amount of waste SF6 is a key problem that needs to be solved urgently.

[0005] Degrading waste SF6 into releasable gas is the main way to reduce its damage to the environment. At present, the main methods for degrading SF6 are pyrolysis, photodegradation, and low-temperature plasma. Although the photolysis method has low energy consumption and is effective in degrading SF6, the photodegradation reaction rate is too slow, and the amount that can be degraded is very limited; the low-temperature plasma method can achieve satisfactory degradation efficiency, but at present it can only achieve low-concentration waste gas treatment, and the equipment is expensive and difficult to promote and apply on a large scale at the industrial level. In addition, almost all SF6 low-temperature plasma degradation schemes will produce toxic, harmful, and even corrosive products such as SO2F2 and HF. Improving product selectivity is a key issue facing this technology.

[0006] The pyrolysis method has the earliest industrial application and the most mature process. The traditional pyrolysis method is to react SF6 gas with CaCO3 in a furnace at 1100°C. This method can convert SF6 gas into harmless solid products CaSO4 and CaF2. However, this method consumes a lot of energy, has high economic costs, and generates toxic gases such as H2S and HF. On this basis, thermal catalytic degradation may become one of the important trends in future development. The introduction of suitable catalysts can not only reduce the temperature required for the reaction, but also regulate the product selectivity to a large extent. In 2009, Kashiwagi et al. studied the catalytic effect of metal phosphates such as Ce, Zr, and Al in the thermal degradation of SF6, and found that CePO4 and AlPO4 have significant advantages in improving degradation efficiency and selectivity. In 2012, Park et al. found that γ-Al2O3 can promote the degradation of SF6, and obtained AlPO4 / γ-Al2O3 with stronger stability, durability and catalytic activity through phosphoric acid titration. In recent years, domestic scholars have achieved thermal degradation of SF6 through SiC-Fe2O3 heterostructure catalysts and explored the mechanism of electronic coupling within the heterostructure. Studies have shown that traditional metal oxide materials and some metal phosphides have a certain promoting effect on the degradation of SF6 waste gas, and can obtain a higher degradation rate under specific laboratory conditions.

[0007] The existing experimental device for thermal catalytic degradation of SF6 is mainly a static air intake heating device. Before the experiment begins, the operator passes a fixed volume and concentration of reaction gas into the equipment, and samples and analyzes the catalytic effect after 8-10 hours. The degradation system mainly has the following problems: First, the contact area between the gas and the catalyst is small, and the reaction gas may flow away from the gap between the quartz tube and the tubular furnace and cannot react completely with the catalyst; second, after static air intake, the gas in the device does not circulate, and only relies on the free diffusion movement of gas molecules to react with the solid catalyst, which also leads to low degradation rate and conversion rate. Third, the flow rate and ratio of the catalyst and reaction gas are only roughly estimated through the pressure changes of the experimental device, which makes it difficult to refine the optimal reaction conditions and analyze the reaction mechanism. In addition, most devices use a one-stage heating device, which only reaches the set temperature in the middle of the heating section. The temperature of the rest of the device is inconsistent, which increases the difficulty of controlling the reaction conditions; most experimental devices can withstand a pressure of only 0.6 to 0.8 MPa, which limits the catalytic reaction conditions. When the pressure increases, the catalytic device may deform and the mechanical interface may be worn. In the long run, this will threaten the life of the experimental device and increase the maintenance cost of the catalytic device.

[0008] Furthermore, the reactor of the existing thermal catalytic degradation experimental device is placed horizontally, and the gas is unevenly distributed due to the influence of gravity, which in turn affects the contact between the gas and the catalyst and affects its degradation performance. Summary of the invention

[0009] The purpose of the present invention is to provide a flow rate controllable SF6 dynamic thermal catalytic degradation pressure-resistant treatment device in view of the shortcomings of the existing SF6 thermal catalytic degradation device, and to provide an SF6 dynamic degradation device, which can effectively regulate the flow rate and mixing ratio of SF6 and the reaction gas, so that SF6 is fully in contact with the catalyst during the catalytic process, greatly improving the catalytic treatment effect, and the experimental platform is equipped with three-stage heating to make the temperature of the reaction section more stable. Through reasonable mechanical design, this device can withstand up to 3MPa gas pressure, reducing the subsequent maintenance pressure. The end of the experimental device is connected to the washing tank and the drying box, which can fully absorb the toxic and harmful gases in the product and further reduce the pollution to the environment.

[0010] The technical solution of the present invention is as follows:

[0011] A SF6 thermal catalytic degradation device comprises a gas feeding unit, a reaction unit and a product post-processing unit. The reaction unit is configured as a vertical reaction tube placed vertically. The SF6 gas is introduced from the top of the reaction unit, moves to the bottom of the reaction unit based on gravity, and then is discharged from the bottom of the reaction unit after pyrolysis. The gas is evenly distributed in the reaction unit and can contact with a catalyst to decompose toxic gases after pyrolysis.

[0012] The setting method of the reaction unit of the present application is different from that of the traditional horizontally placed reaction unit. The flow pattern of the gas in the reaction unit is consistent with the direction of gravity, thereby avoiding the situation where the gas is affected by gravity and unevenly distributed inside the device, affecting the catalytic efficiency of the catalyst, thereby improving the gas pyrolysis efficiency.

[0013] Preferably, the reaction unit includes a reactor, which includes an upper air inlet and a lower air outlet, the air inlet is connected to the air outlet of the gas feeding unit, and the gas is fed into the reaction unit through the air inlet above the reaction unit after being taken in and mixed by the gas feeding unit; the air outlet below the reaction unit is connected to the product post-processing unit, and the product post-processing unit further removes harmful gases in the pyrolysis gas.

[0014] According to a preferred embodiment, the reaction unit further comprises a heating device disposed outside the reactor for heating the reactor and the gas inside the reactor. The heating device is, for example, a three-stage isothermal electric heating device to implement a preheating-heating-insulation process for the gas, so that all the gas in the reactor can reach and maintain a suitable reaction temperature.

[0015] Preferably, the heating device is equipped with TTS over-temperature protection, which realizes high-temperature interlocking independently of the control system to ensure timely response and prevent potential safety accidents under high temperature conditions. The reactor is placed vertically, and the gas enters from the top, so that SF6 can experience a reaction section as long as 10-15cm in a single reaction process, and the reaction temperature is more stable and the reaction is more complete;

[0016] Preferably, the reactor is a fixed bed reactor. Preferably, a pressure transmitter, a discharge valve, a filter, etc. are also provided upstream of the reactor.

[0017] Preferably, a catalyst support member is designed inside the reactor to place the catalyst. The catalyst support member arranged in the reaction tube is, for example, an annular support member, which is used to support the catalyst so that the catalyst can be placed more evenly inside the reaction tube, thereby increasing the contact space between the catalyst and the reaction gas. Preferably, the annular support member is arranged to be arranged around the inner wall of the reaction tube as a whole to ensure that the gas passing through the reaction tube can contact the catalyst. Preferably, a hole for gas to pass through is provided on the annular support member. The annular support member can be arranged in the reaction tube through a leg.

[0018] Preferably, the reactor is configured as a reaction tube, and the center of the reactor is designed to contain a thermocouple sleeve, and the thermocouple can be placed in the thermocouple sleeve to detect the temperature of the center of the reactor.

[0019] Preferably, the reactor material is Inconel600, the operating temperature is RT-1000°C, and the operating pressure is 0-3MPa.

[0020] The reaction unit is equipped with a temperature controller and a pressure monitor. Three temperature controllers are set corresponding to the three-stage isothermal electric heating device, corresponding to the upper, middle and lower sections of the three-stage isothermal electric heating device respectively. The segmented temperature rise and constant temperature can be set before the experiment starts to achieve programmed temperature rise. Preferably, a thermocouple of one of the temperature controllers is connected to a thermocouple sleeve for real-time monitoring of the temperature change of the catalyst reaction section. The pressure monitor is used to detect the pressure change in the reactor so that the operator can adjust the inlet and outlet flow rates in time to control the reaction conditions.

[0021] According to a preferred embodiment, the gas feeding unit includes a first gas circuit, a second gas circuit and a third gas circuit, and the first gas circuit, the second gas circuit and the third gas circuit are all provided with a stop valve, a filter, a one-way valve and a gas mass flow controller. The first gas circuit, the second gas circuit and the third gas circuit are respectively connected to high-pressure gas cylinders containing different reaction gases. After the gas flow rate is set according to the required ratio of different reaction gases, multiple reaction gas components are controlled to be introduced at the same time, and after being mixed in a mixer (not shown in the figure), they enter the reaction unit. The gas flow rate in each gas circuit is controlled separately by a gas mass flow controller, and then the mixing ratio of each component gas is controlled to achieve a uniform ratio of the gas introduced into the reactor and facilitate the control of the gas pressure at all times.

[0022] The different reaction gases are raw gas and catalytic gas, for example, SF6, N2, O2, H2, He or a pre-configured reaction gas mixture. The first gas path, the second gas path and the third gas path are respectively connected to containers of different gases, and can control the gas flow separately, and keep them unobstructed as needed during use, so that the gas in the device continues to flow. The unused gas path remains closed.

[0023] The gas mass flow controller has a control accuracy of ≤±1% FS and a pressure tolerance of 10 MPa.

[0024] The mixer adopts a Venturi mixer structure, is made of 316L material, has an operating temperature of ≤60°C, and an operating pressure of 0-3Mpa.

[0025] The reaction gas enters from the top of the reactor and reacts under a certain temperature, pressure and catalyst. The product is discharged from the bottom of the reactor and enters the product post-processing unit.

[0026] The product post-processing unit includes a washing tank and a dryer.

[0027] The product coming out of the reactor first enters the washing tank to absorb the acid gas (HF, H2S) therein, and then passes through the dryer for drying before entering the back pressure valve for controlled release.

[0028] Preferably, a bypass gas outlet is provided on the pipeline after the gas comes out of the reactor and before it enters the washing tank, so as to obtain the gas composition after coming out of the reactor for detection.

[0029] Preferably, the washing tank is a tank body with an effective volume of 500mL, made of 316L, with an operating temperature of RT-100°C and an operating pressure of 0-3MPa. A PTFE liner is provided inside the washing tank, and the liner is detachably connected to the washing tank. Adding an absorbent into the PTFE tank can effectively prevent corrosion of the washing tank. The internal PTFE liner can be removed for cleaning and replacement, which is more conducive to extending the service life of the washing tank.

[0030] Preferably, the effective volume of the dryer is 300 mL, the material is 316L, and the operating temperature and pressure are normal temperature and pressure. Desiccant can be filled in the drying tank as needed to ensure that the moisture in the gas is effectively absorbed and removed.

[0031] The system pressure is controlled by a back pressure valve. The back pressure valve is designed with a bypass, and a mechanical pressure gauge and filter are designed at the front end. The gas release can be manually controlled through the main exhaust channel through a mechanical valve to release all the gas; the gas discharge volume can also be adjusted through the back pressure valve to keep the internal gas pressure stable.

[0032] Back pressure valve range: 0~500psi. Pressure transmitter range: 0~6MPa, accuracy ≤0.5%FS.

[0033] Preferably, the control unit can adopt AI intelligent instrument and / or manual control scheme. The temperature, gas flow rate, etc. can be controlled by panel instrument. The main valves and joints of the device are made of 316L, with a pressure tolerance of 207bar@-54-38℃. The pipeline material is 316L, and the main specification is 1 / 8in.

[0034] Preferably, the reaction unit further comprises a heat-insulating layer, and the reactor and the heating device are both arranged in the heat-insulating layer to maintain the reaction temperature. Preferably, the heat-insulating layer is arranged to be openable and closable. Preferably, the opening and closing can be by arranging a zipper.

[0035] Preferably, the device is provided with a multi-level alarm system, and a safety pressure relief valve is provided at a key position. When the pressure reaches the upper limit (Hi), the pressure relief valve will actively release the system pressure. Preferably, an audible and visual alarm device is also connected. When the temperature reaches the upper limit (Hi), the system generates an audible and visual alarm to remind the operator to handle it, which can effectively ensure the safety of personnel.

[0036] Preferably, it also includes a housing, on which are provided positions for installing components of the gas feed unit, the reactor and the components of the gas post-processing unit, so as to integrate the devices and facilitate overall movement. The housing can be designed according to the shape and size of the devices.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. A SF6 dynamic degradation device, in which a mass controller is installed in the initial gas path of the raw gas, which can accurately adjust the intake flow rate and ratio of SF6 and catalytic gas, so as to study the influence of catalytic gas with different concentration ratios on the degradation of SF6, find a better intake flow rate, and facilitate the subsequent combination with simulation calculation to analyze the specific reaction and catalytic mechanism of the catalytic process; it can provide a dynamic test platform for the high-temperature reaction of SF6 and the catalyst, so that SF6 is always driven by the airflow during the contact process with the catalyst, and at the same time, it can keep the air pressure in the test gas path stable and ensure the smooth flow of gas in the entire gas path, so that the gas and solid are fully contacted and reacted, greatly improving the catalytic efficiency;

[0039] 2. A SF6 dynamic degradation device, in which the reactor is placed vertically so that gravity assists the gas flow to avoid uneven gas distribution and improve the catalytic efficiency of the gas; a catalyst placement platform is set in the reaction tube to increase the contact area between the catalyst and the gas; and the gas feeding unit, reaction unit and product post-processing unit are integrated as a whole, which is more standardized and integrated; it is conducive to the overall movement of the device, which can save space and improve experimental efficiency.

[0040] 3. A SF6 dynamic degradation device with high safety, good resistance to high temperature and high pressure, stable and controllable reaction conditions, able to withstand pressures up to 3MPa, and able to be used for a long time at high temperatures of 1000℃.

[0041] 4. A SF6 dynamic degradation device, the system terminal uses a liquid crystal display, which can monitor the temperature and pressure inside the equipment in real time. The device control system uses AI intelligent instruments combined with manual control solutions, which is friendly to human-computer interaction and convenient for personnel training and learning.

[0042] 5. A SF6 dynamic degradation device. The device of the present invention makes up for the shortcomings of the existing SF6 thermal catalytic degradation device, such as low gas utilization rate and difficult treatment of SF6 gas degradation products. During the experiment, the device is easy to disassemble and simple to operate, providing a simple and easy-to-use method and experimental platform for the industrial application and teaching application of SF6 degradation catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A side cross-sectional view of a SF6 dynamic degradation device of the present invention;

[0044] Figure 2 A cross-sectional view of a reactor of a SF6 dynamic degradation device of the present invention;

[0045] Figure 3 This is a front cross-sectional view of a SF6 dynamic degradation device of the present invention;

[0046] Figure 4 It is an external structural diagram of a reaction unit of a SF6 dynamic degradation device of the present invention.

[0047] List of reference numerals: 100 - reaction unit, 110 - reactor, 111 - air inlet, 112 - air outlet, 113 - catalyst support member, 114 - thermocouple sleeve, 120 - heating device, 130 - insulation layer, 210 - first gas path, 220 - second gas path, 230 - third gas path, 211 - gas mass flow controller, 310 - alkali washing tank, 311 - bypass gas outlet, 320 - drying tank, 400 - back pressure valve. DETAILED DESCRIPTION

[0048] The specific embodiments listed in the present invention are only examples of the present invention, and the present invention is not limited to the specific embodiments described below. For those skilled in the art, any equivalent modifications and substitutions to the embodiments described below are also within the scope of the present invention. Therefore, the equal transformations and modifications made without departing from the spirit and scope of the present invention should be included in the scope of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturers are not specified for all reagents or instruments, they are all conventional products that can be purchased commercially. In order to better illustrate the present invention, numerous specific details are given in the specific embodiments below. It should be understood by those skilled in the art that the present invention can also be implemented without certain specific details. In other embodiments, the methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the purport of the present invention.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art. Unless otherwise specified, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0050] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0051] Example 1

[0052] A SF6 thermal catalytic degradation device, such as Figure 1-4 As shown, it includes a gas feeding unit, a reaction unit 100 and a product post-processing unit. The reaction unit 100 is arranged to be placed vertically. The SF6 gas is fed from the top of the reaction unit 100, moves to the bottom of the reaction unit 100 based on gravity, and then exhausts from the bottom of the reaction unit 100 after pyrolysis. The gas is evenly distributed in the reaction unit 100, which can ensure full contact with the catalyst and then decompose the toxic gas after pyrolysis. The SF6 thermal catalytic degradation device also includes a shell, and the shell is provided with positions for installing the elements of the gas feeding unit 200, the reactor 110 and the elements of the gas post-processing unit, so as to integrate the various devices and facilitate overall movement. The shell can be designed according to the shape and size of each device.

[0053] The setting method of the reaction unit 100 of the present application is different from the traditional horizontal placement of the reaction unit 100. The flow mode of the gas in the reaction unit 100 is consistent with the direction of gravity, thereby avoiding the situation where the gas is affected by gravity and unevenly distributed inside the device, affecting the catalytic efficiency of the catalyst, thereby improving the gas pyrolysis efficiency.

[0054] Preferably, the reaction unit 100 includes a reactor 110, and the reactor 110 includes an upper air inlet 111 and a lower air outlet 112, the air inlet 111 is connected to the gas outlet of the gas feeding unit 200, and the gas is fed into the reaction unit 100 through the air inlet 111 above the reaction unit 100 after being taken in and mixed by the gas feeding unit 200; the air outlet 112 below the reaction unit 100 is connected to the product post-processing unit, and the gas pyrolyzed in the reaction unit 100 is further removed from harmful gases in the pyrolysis gas by the product post-processing unit.

[0055] According to a preferred embodiment, the reaction unit 100 further includes a heating device 120 disposed outside the reactor 110 for heating the reactor 110 and the gas inside the reactor 110. The heating device 120 is, for example, a three-stage isothermal electric heating device to implement a preheating-heating-insulation process for the gas, so that all the gas in the reactor 110 can reach and maintain a suitable reaction temperature. Preferably, the heating device 120 can be composed of a plurality of heating rods with separate temperature control capabilities, and the temperature of the heating rods should be able to reach above 700°C.

[0056] Preferably, the heating device 120 is equipped with TTS over-temperature protection, and high-temperature interlock is realized independently of the control system to ensure timely response and prevent potential safety accidents under high temperature conditions. Preferably, the length of the reactor 110 is 20-30 cm, and the length of the heated reaction section is about 10-15 cm, for example, 12 cm. SF6 gas can experience a reaction section as long as 10-15 cm in a single reaction process, and the reaction temperature is more stable and the reaction is more complete.

[0057] Preferably, the reactor 110 is a fixed bed reactor 110. Preferably, the reactor 110 is also equipped with gas supporting facilities such as a pressure transmitter, an unloading valve, and a filter upstream to control the quality and pressure of the intake gas.

[0058] Preferably, if Figure 2 As shown, a catalyst support member 113 is designed inside the reactor 110, and the catalyst support member 113 is arranged in the reactor 110 through a support leg so as to place the catalyst. The catalyst support member 113 arranged in the reaction tube is, for example, an annular support member, which surrounds the inner wall of the reactor 110, so that the catalyst can be placed more evenly inside the reaction tube, thereby increasing the contact space between the catalyst and the reaction gas. The annular support member is provided with holes for gas to pass through, and the gas can expand the contact area with the catalyst after passing through the support member.

[0059] Preferably, the reactor 110 is configured as a reaction tube, and a thermowell 114 is designed at the center of the reactor 110 to accommodate a thermocouple. After the thermocouple is placed in the thermowell 114 , it can be used to detect the temperature at the center of the reactor 110 .

[0060] Preferably, the reactor 110 may be configured without the thermocouple sleeve 114, and other temperature detectors that do not require thermocouples may be used to detect the reaction temperature.

[0061] SF6 gas flows in from the top of the reaction tube and flows out from the bottom, generating a pyrolysis reaction. Preferably, the reactor 110 is made of Inconel600, with an operating temperature of RT-1000°C and an operating pressure of 0-3MPa.

[0062] According to a preferred embodiment, the reaction unit 100 is equipped with a temperature controller and a pressure monitor. For example, three temperature controllers are provided corresponding to the three-stage isothermal electric heating device, corresponding to the upper, middle and lower sections of the three-stage isothermal electric heating device 120, respectively. Before the experiment begins, the segmented temperature rise and constant temperature can be set to achieve programmed temperature rise. Preferably, the thermocouple of one of the temperature controllers is connected to the thermocouple sleeve 114 for real-time monitoring of the temperature change of the catalyst reaction section. The pressure monitor is used to detect the pressure change in the reactor 110 so that the operator can adjust the inlet and outlet flow rates in time to control the reaction conditions.

[0063] According to a preferred embodiment, the gas feeding unit includes a first gas circuit 210, a second gas circuit 220 and a third gas circuit 230, and the first gas circuit 210, the second gas circuit 220 and the third gas circuit 230 are all provided with supporting facilities such as a stop valve, a filter, a one-way valve and a gas mass flow controller 211. The first gas circuit 210, the second gas circuit 220 and the third gas circuit 230 are respectively connected to high-pressure gas cylinders containing different reaction gases. After setting the gas flow rate according to the required ratio of different reaction gases, multiple reaction gas components are controlled to be introduced at the same time, and after being mixed by a venturi mixer (not shown in the figure), they enter the reaction unit 100. The gas mass flow controller 211 controls the gas flow in each gas circuit respectively, and then controls the mixing ratio of each component gas, so as to achieve a uniform ratio of the gas introduced into the reactor 110 and facilitate the control of the gas pressure at all times. The gas introduction method is set to be continuously introduced to promote gas flow and improve pyrolysis efficiency.

[0064] The different reaction gases are raw material gas and catalytic gas, for example, SF6, N2, O2, H2, He or a pre-configured reaction gas mixture.

[0065] The gas mass flow controller 211 is, for example, a mass flow controller of the Qixing Huachuang CS series, with a control accuracy of ≤±1% FS and a pressure tolerance of 10 MPa.

[0066] The mixer adopts a Venturi mixer structure, is made of 316L material, has an operating temperature of ≤60°C, and an operating pressure of 0-3Mpa.

[0067] The reaction gas enters from the top of the reactor 110 and reacts under a certain temperature, pressure and catalyst. The product is discharged from the bottom of the reactor 110 and enters the product post-processing unit.

[0068] The product post-processing unit includes a washing tank and a dryer.

[0069] The product coming out of the reactor 110 first enters the scrubbing tank to absorb the acid gas (HF, H2S) therein, and then passes through the dryer for drying before entering the back pressure valve 400 to control the release.

[0070] Preferably, if Figure 3 As shown, a bypass gas outlet 311 is also provided on the pipeline before the gas comes out of the reactor 110 and enters the washing tank, so as to obtain the gas composition after coming out of the reactor 110 for detection.

[0071] Preferably, the washing tank is a tank body with an effective volume of 500mL, made of 316L, with an operating temperature of RT-100°C and an operating pressure of 0-3MPa. A PTFE liner is provided inside the washing tank, and the liner is detachably connected to the washing tank. Adding an absorbent into the PTFE tank can effectively prevent corrosion of the washing tank. The internal PTFE liner can be removed for cleaning and replacement, which is more conducive to extending the service life of the washing tank. Preferably, the PTFE tank can be loaded with solutions such as sodium hydroxide.

[0072] Preferably, the effective volume of the dryer is 300 mL, the material is 316L, and the operating temperature and pressure are normal temperature and pressure. The drying tank 320 can be filled with desiccant as needed to ensure that the moisture in the gas is effectively absorbed and removed.

[0073] Preferably, the system pressure is controlled by a back pressure valve 400. The back pressure valve 400 is designed with a bypass, and a mechanical pressure gauge and a filter are designed at the front end. The gas release can be manually controlled through the main exhaust channel through a mechanical valve to release all the gas; the gas discharge volume can also be controlled and adjusted through the back pressure valve 400 to keep the internal gas pressure stable. The back pressure valve is, for example, a GENTEC R78 series high-precision back pressure valve.

[0074] Back pressure valve 400 range: 0~500psi. Pressure transmitter range: 0~6MPa, accuracy ≤0.5%FS.

[0075] Preferably, the control unit can adopt AI intelligent instrument and / or manual control scheme. The temperature, gas flow rate, etc. can be controlled by panel instrument. The main valves and joints of the device are made of 316L, with a pressure tolerance of 207bar@-54-38℃. The pipeline material is 316L, and the main specification is 1 / 8in.

[0076] Preferably, if Figure 4 As shown, the reaction unit 100 also includes a heat-insulating layer 130, and the reactor 110 and the heating device 120 are both arranged in the heat-insulating layer 130 to maintain the reaction temperature. Preferably, the heat-insulating layer 130 is configured to be openable and closable. Preferably, the opening and closing can be by setting a zipper. The heat-insulating layer 130 can be foam, rubber and plastic heat-insulating material, polyurethane foam, polystyrene foam, aerogel, fiber material, etc.

[0077] Preferably, the device is provided with a multi-level alarm system, and a safety pressure relief valve is provided at a key position. When the pressure reaches the upper limit (Hi), the pressure relief valve will actively release the system pressure. It is also connected with an audible and visual alarm device. When the temperature reaches the upper limit (Hi), the system generates an audible and visual alarm to remind the operator to handle it, which can effectively ensure the safety of personnel.

[0078] Here’s how this application works:

[0079] SF6 gas and other catalytic gases enter the mixer through the first gas path 210, the second gas path 220 and the third gas path 230 respectively under the action of the gas mass flow controller 211, enter the reactor 110 from the upper part of the reaction tube after being mixed in the mixer, flow through the catalyst from top to bottom and are pyrolyzed before being discharged from the gas outlet 112 of the reactor 110, and the discharged gas can be sampled through the bypass gas outlet 311; the remaining gas enters the alkali washing tank 310, removes the acid gas, and then enters the drying tank 320 to remove the moisture before being discharged through the gas outlet or through the back pressure valve 400.

[0080] Example 2

[0081] Taking an actual formal experiment as an example, the experimental parameters are: 4% SF6 + 96% Air, inlet flow rate 5 ml / min, temperature 700°C, initial pressure 0.4 MPa, 1g FeCe@ZIF-8 + 0.2g quartz wool (the two are mixed to disperse the catalyst in space).

[0082] a. Loading the catalyst. Disassemble the reaction tube, gently fix a layer of quartz wool on the catalyst support member 113 in the tube, feed the catalyst support member 113 from the lower end of the vertical reaction tube, weigh 1g of FeCe@ZIF-8 and 0.2g of quartz wool, mix them evenly, and then slowly feed them from the upper end of the reaction tube to the catalyst support member 113 in the reaction tube (make sure that the quartz wool is dispersed into fluffy balls before entering the tube); tighten the screws, install the reaction tube, and then fix it in the insulation layer 130, then insert the K-type thermocouple probe into the thermocouple sleeve 114 of the reaction tube (reflecting the real-time temperature in the furnace), and tighten the screws.

[0083] b. Washing and filling. Evacuate the air chamber, then inject N2, and connect the 5 / 8-1 / 8 pressure reducing valve to evacuate again, repeat this process 3 times to eliminate the residual gas and moisture in the air chamber. After washing, connect the first air path 210 and the second air path 220 to fill the air chamber with SF6 (4%) and air (96%) in proportion, and mix them in the venturi mixer to form a mixed gas. Adjust the flow rate of the mixed gas to 5ml / min, and control the air pressure at 0.4Mpa. Allow it to circulate for 20 minutes before heating to stabilize the airflow.

[0084] c. Set the parameters of reactor 110, heat up, and conduct experiments. The reactor is set up with three sections for heating: upper, middle, and lower. The middle section is the main reaction area, and the temperature of the middle section is accurately monitored by a K-type thermocouple. Set the experimental temperature to 700°C, set the heating time to 35 minutes, and record the reading of the K-type thermocouple thermometer after the heating is completed to ensure that the temperature is 700±5°C, otherwise repeat the experiment.

[0085] d. Sampling and testing. During the experiment, starting from 700°C (including 700°C), a special polyvinyl fluoride sampling bag was used to collect gas at the bypass gas outlet 311 every hour, and the sampled gas was passed into the GC-MS device for qualitative and quantitative analysis. After the experiment, the catalyst in the reaction tube was collected after the reaction, and its morphology and appearance changes were observed using characterization techniques such as XRD and TEM.

[0086] e. Waste gas treatment. During the experiment, the waste gas is discharged after passing through the alkali washing tank 310, and the alkali washing tank 310 is replaced regularly. After the reaction is completed, the waste gas in the device may contain a lot of toxic and harmful acidic gases. Therefore, after the device is cooled, N2 is used again to evenly send the residual gas inside the reaction device into the alkali washing tank 310 and the drying tank 320. This process lasts for 20 minutes before the device can be disassembled.

[0087] f. Disassembly and cleaning of the device. Use anhydrous ethanol to repeatedly scrub the inner wall of the vertical reaction tube until the cloth strip is no longer stained by the inner wall. After the internal parts of the vertical reaction tube are scrubbed clean, put them together in the drying oven to prepare for the next experiment.

[0088] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A SF6 dynamic degradation device, characterized in that: The invention comprises a gas feeding unit (200), a reaction unit (100) and a product post-processing unit, wherein the reaction unit (100) is configured as a vertical reaction tube placed vertically.

2. A SF6 dynamic degradation device according to claim 1, characterized in that: The reaction unit (100) comprises a reactor (110), wherein the reactor (110) comprises an upper gas inlet (111) and a lower gas outlet (112), wherein the gas inlet (111) is connected to the gas outlet of the gas feeding unit (200); and the gas outlet (112) is connected to a product post-processing unit.

3. A SF6 dynamic degradation device according to claim 2, characterized in that: The reactor (110) further includes a heating device (120) disposed outside the reactor (110).

4. The SF6 dynamic degradation device according to claim 3 is characterized in that: The heating device (120) is a multi-stage isothermal heating device, and the heating device (120) is fixed to the outer wall of the reactor (110) via a fixing member.

5. The SF6 dynamic degradation device according to claim 3 is characterized in that: The length of the reactor (110) is 20 cm to 30 cm, and the length of the heating device (120) is 10 cm to 15 cm.

6. The SF6 dynamic degradation device according to claim 1 is characterized in that: A catalyst support member (113) is arranged inside the reactor (110). The catalyst support member (113) is annular and has holes for gas to pass through.

7. The SF6 dynamic degradation device according to claim 1 is characterized in that: The gas feeding unit (200) comprises a first gas path (210), a second gas path (220) and a third gas path (230) capable of individually controlling gas flow rates; the first gas path (210), the second gas path (220) and the third gas path (230) are respectively connected to containers of different gases so as to simultaneously introduce different gases into the reactor (110).

8. The SF6 dynamic degradation device according to claim 3 is characterized in that: A thermowell (114) for accommodating a thermocouple is disposed at the center of the reactor (110).

9. The SF6 dynamic degradation device according to claim 1, characterized in that: The reaction unit (100) further comprises a heat-insulating layer (130), and the reactor (110) and the heating device (120) are both arranged in the heat-insulating layer (130).

10. The SF6 dynamic degradation device according to claim 1, characterized in that: The product post-processing unit comprises a washing tank and a dryer, wherein the gas inlet of the washing tank is connected to the gas outlet (112) of the reactor (110), and the gas outlet of the washing tank is connected to the gas inlet of the dryer.

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