Sulfur hexafluoride and mixed gas purification device

Abstract

The utility model is suitable for the technical field of electrical equipment insulating gas treatment, and provides a sulfur hexafluoride and mixed gas purification device. The device comprises a first rotary valve, mixed gas membrane separation equipment, multi-tower SF6 gas rectification and purification equipment, pressure swing adsorption equipment and liquid filling equipment, one port of the first rotary valve is used for feeding gas, and the other two ports of the first rotary valve are respectively communicated with the multi-tower SF6 gas rectification purification equipment and the mixed gas membrane separation equipment; an outlet of the mixed gas membrane separation equipment is communicated with the pressure swing adsorption equipment, and an outlet of the pressure swing adsorption equipment is connected with the external environment; a regenerated SF6 gas channel is arranged between the pressure swing adsorption equipment and the mixed gas membrane separation equipment; an outlet of the multi-tower SF6 gas rectification and purification equipment is connected with liquid filling equipment, and the liquid filling equipment is connected with an SF6 steel cylinder; and a finished product gas channel and an exhaust gas channel are arranged between the mixed gas membrane separation equipment and the multi-tower SF6 gas rectification and purification equipment. The SF6 gas purification device can improve the purification degree of the SF6 gas.

Description

Technical Field

[0001] The utility model belongs to the technical field of insulating gas treatment of electrical equipment, and in particular relates to a sulfur hexafluoride and mixed gas purification device. Background Art

[0002] Sulfur hexafluoride (SF6) gas is a good insulating arc extinguishing medium and is widely used in high-voltage electrical equipment. In recent years, with the rapid development of power grids, the use of sulfur hexafluoride gas has also increased year by year, but sulfur hexafluoride gas is a strong greenhouse gas, and the exhaust gas discharged after purification by the existing sulfur hexafluoride gas purification device still contains a certain amount of sulfur hexafluoride. Therefore, it is necessary to develop a sulfur hexafluoride gas purification device to reduce the sulfur hexafluoride component in the exhaust gas, avoid resource waste and reduce the greenhouse effect. Utility Model Content

[0003] In view of this, the utility model provides a sulfur hexafluoride and mixed gas purification device, which can.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] The embodiment of the utility model provides a sulfur hexafluoride and mixed gas purification device, including: a first rotary valve, a mixed gas membrane separation device, a multi-tower SF6 gas distillation and purification device, a pressure swing adsorption device and a liquid filling device;

[0006] The first port of the first rotary valve is connected to the gas to be purified, the second port is connected to the inlet of the multi-tower SF6 gas distillation and purification equipment, and the third port is connected to the inlet of the mixed gas membrane separation equipment;

[0007] The outlet of the mixed gas membrane separation device is connected to the pressure swing adsorption device, and the outlet of the pressure swing adsorption device is connected to the external environment; wherein a regeneration SF6 gas channel is provided between the pressure swing adsorption device and the mixed gas membrane separation device, one end of the regeneration SF6 gas channel is connected to the inlet of the mixed gas membrane separation device, and the other end is connected to the middle of the pressure swing adsorption device;

[0008] The outlet of the multi-tower SF6 gas distillation and purification equipment is connected to the liquid filling equipment, and the liquid filling equipment is connected to the SF6 cylinder;

[0009] Among them, a finished gas channel and an exhaust gas channel are arranged between the mixed gas membrane separation equipment and the multi-tower SF6 gas distillation and purification equipment; the inlet of the finished gas channel is connected to the mixed gas membrane separation equipment, and the outlet of the finished gas channel is connected to the multi-tower SF6 gas distillation and purification equipment; the inlet of the exhaust gas channel is connected to the multi-tower SF6 gas distillation and purification equipment, and the outlet of the exhaust gas channel is connected to the mixed gas membrane separation equipment.

[0010] In the embodiment of the utility model, the first port of the first rotary valve is connected with the second port, so that the SF6 gas with higher purity can be introduced into the multi-tower SF6 gas distillation and purification equipment for purification; the first port of the first rotary valve is connected with the third port, so that the SF6 gas with lower purity can be introduced into the mixed gas membrane separation equipment for membrane separation. The liquid SF6 obtained after purification by the multi-tower SF6 gas distillation and purification equipment is pressurized into the SF6 cylinder through the liquid filling equipment, and the mixed gas is discharged to the mixed gas membrane separation equipment for further membrane separation treatment. The SF6 gas separated by the membrane of the mixed gas membrane separation equipment enters the multi-tower SF6 gas distillation and purification equipment through the finished gas channel, and the separated tail gas enters the pressure swing adsorption equipment. Afterwards, the molecular sieve in the pressure swing adsorption equipment can adsorb the SF6 in the separated tail gas, and the regenerated SF6 gas enters the mixed gas membrane separation equipment through the regenerated SF6 gas channel for re-separation, and other gases in the separated tail gas are discharged through the outlet of the pressure swing adsorption equipment.

[0011] It can be seen that the degree of purification of SF6 gas can be improved as much as possible through the treatment process of the SF6 gas entering the sulfur hexafluoride and mixed gas purification device.

[0012] In some embodiments, the mixed gas membrane separation device includes a first filter, a compressor, a second filter, a primary membrane, and a secondary membrane that are connected in sequence;

[0013] The permeate side of the secondary membrane is communicated with the inlet of the compressor, the inlet of the first filter is communicated with the third port of the first rotary valve, and the outlet of the secondary membrane is communicated with the multi-tower SF6 gas distillation and purification equipment through the outlet of the finished gas channel;

[0014] Wherein, the filtering accuracy of the second filter is higher than the filtering accuracy of the first filter.

[0015] Optionally, the mixed gas membrane separation device further includes a molecular sieve and a heater;

[0016] The molecular sieve is located between the compressor and the second filter, and the compressor, the molecular sieve and the second filter are connected in sequence;

[0017] The heater is located between the second filter and the primary membrane, and the second filter, the heater and the primary membrane are connected in sequence.

[0018] Exemplarily, the number of the compressors is at least two, and the at least two compressors jointly provide the pressure required for gas separation, which is less than or equal to 1.2 Mpa;

[0019] The second filter is a filter capable of filtering out dust particles with a diameter greater than 0.005 μm.

[0020] Illustratively, the heater heats the gas to 45°C.

[0021] In some embodiments, the multi-tower SF6 gas distillation and purification equipment includes a refrigerator, a reboiler, a sulfur hexafluoride liquid storage unit and a plurality of distillation and purification towers;

[0022] The multiple distillation and purification towers are connected in sequence, and the distillation and purification towers at both ends are respectively provided with an air inlet and an exhaust port, the air inlet is connected to the second port of the first rotary valve, and the exhaust port is connected to the mixed gas membrane separation device through the exhaust gas channel;

[0023] The refrigerator provides liquid reflux from the tops of the multiple distillation and purification towers, and the reboiler provides gas reflux from the bottoms of the multiple distillation and purification towers;

[0024] The bottoms of the multiple distillation and purification towers are all connected to the sulfur hexafluoride liquid storage unit.

[0025] Exemplarily, the number of the multiple distillation purification towers is three.

[0026] Optionally, each of the multiple distillation and purification towers is provided with a vertically arranged refrigeration coil, and each refrigeration coil is connected to the refrigerator.

[0027] In some embodiments, the pressure swing adsorption device includes a second rotary valve, a first molecular sieve group, a second molecular sieve group, a third rotary valve, and a fourth rotary valve;

[0028] The first port of the second rotary valve is communicated with the outlet of the mixed gas membrane separation device, the second port of the second rotary valve is communicated with the first port of the first molecular sieve group, and the third port of the second rotary valve is communicated with the first port of the second molecular sieve group;

[0029] The second port of the first molecular sieve group is in communication with the second port of the third rotary valve, the second port of the second molecular sieve group is in communication with the third port of the third rotary valve, and the first port of the third rotary valve is connected to the external environment;

[0030] The first port of the fourth rotary valve is connected to the inlet of the mixed gas membrane separation device, the second port of the fourth rotary valve is connected to the first port of the first molecular sieve group, and the third port of the fourth rotary valve is connected to the first port of the second molecular sieve group.

[0031] Exemplarily, the first molecular sieve group and the second molecular sieve group each include at least two molecular sieves connected in sequence. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0033] Figure 1 A schematic diagram of the structure of a sulfur hexafluoride and mixed gas purification device provided in an embodiment of the utility model;

[0034] Figure 2 A schematic diagram of the structure of a mixed gas membrane separation device provided in an embodiment of the utility model;

[0035] Figure 3 A schematic diagram of the structure of a multi-tower SF6 gas distillation and purification device provided in an embodiment of the utility model;

[0036] Figure 4 A schematic structural diagram of a pressure swing adsorption device provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0037] In the following description, specific details such as specific system structures and technologies are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details that hinder the description of the present invention.

[0038] In order to make the purpose, technical solutions and advantages of the utility model clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0039] See also Figure 1 The sulfur hexafluoride and mixed gas purification device provided in the embodiment of the utility model may include a first rotary valve 10, a mixed gas membrane separation device 20, a multi-tower SF6 gas distillation and purification device 30, a pressure swing adsorption device 40 and a liquid filling device 50.

[0040] The first port of the first rotary valve 10 is connected to the gas to be purified, the second port is connected to the inlet of the multi-tower SF6 gas distillation and purification equipment 30 , and the third port is connected to the inlet of the mixed gas membrane separation equipment 20 .

[0041] The outlet of the mixed gas membrane separation device 20 is connected to the pressure swing adsorption device 40, and the outlet of the pressure swing adsorption device 40 is connected to the external environment. A regeneration SF6 gas channel is provided between the pressure swing adsorption device 40 and the mixed gas membrane separation device 20, one end of the regeneration SF6 gas channel is connected to the inlet of the mixed gas membrane separation device 20, and the other end is connected to the middle of the pressure swing adsorption device 40.

[0042] The outlet of the multi-tower SF6 gas distillation and purification equipment 30 is connected to the liquid filling equipment 50, and the liquid filling equipment 50 is connected to the SF6 cylinder.

[0043] Among them, a finished gas channel and an exhaust gas channel are provided between the mixed gas membrane separation device 20 and the multi-tower SF6 gas distillation and purification device 30. The inlet of the finished gas channel is connected to the mixed gas membrane separation device 20, and the outlet of the finished gas channel is connected to the multi-tower SF6 gas distillation and purification device 30. The inlet of the exhaust gas channel is connected to the multi-tower SF6 gas distillation and purification device 30, and the outlet of the exhaust gas channel is connected to the mixed gas membrane separation device 20.

[0044] The working process of sulfur hexafluoride and mixed gas purification device is:

[0045] When the SF6 gas purity of the gas entering the air inlet is greater than a predetermined proportion (for example, 90%), the first port of the first rotary valve 10 is connected to the second port, and the gas entering from the first port enters the multi-tower SF6 gas distillation and purification equipment 30, and is purified by the multi-tower SF6 gas distillation and purification equipment 30. When the purity of the purified gas reaches more than 99.9%, the exhaust gas channel at the top of the multi-tower SF6 gas distillation and purification equipment 30 is opened, and the mixed gas at the top is discharged to the mixed gas membrane separation equipment 20; the liquid SF6 at the bottom of the multi-tower SF6 gas distillation and purification equipment 30 is pressurized into the SF6 cylinder through the liquid filling equipment 50.

[0046] When the SF6 gas concentration of the gas entering the gas inlet is less than a predetermined ratio, the first port of the first rotary valve 10 is connected to the third port, and the gas entering from the first port enters the mixed gas membrane separation device 20. The SF6 gas separated by the membrane of the mixed gas membrane separation device 20 enters the multi-tower SF6 gas distillation and purification device 30 through the finished gas channel, and the separated tail gas enters the pressure swing adsorption device 40. The molecular sieve in the pressure swing adsorption device 40 can adsorb the SF6 in the separated tail gas, and the regenerated SF6 gas enters the mixed gas membrane separation device 20 through the regenerated SF6 gas channel for re-separation, and other gases in the separated tail gas are discharged through the outlet of the pressure swing adsorption device 40.

[0047] In this embodiment, the first port of the first rotary valve 10 is connected to the second port, so that the SF6 gas with higher purity can be introduced into the multi-tower SF6 gas distillation and purification equipment 30 for purification; the first port of the first rotary valve 10 is connected to the third port, so that the SF6 gas with lower purity can be introduced into the mixed gas membrane separation equipment 20 for membrane separation. The liquid SF6 obtained after purification by the multi-tower SF6 gas distillation and purification equipment 30 is pressurized into the SF6 cylinder through the liquid filling equipment 50, and the mixed gas is discharged to the mixed gas membrane separation equipment 20 for further membrane separation treatment. The SF6 gas after membrane separation by the mixed gas membrane separation equipment 20 enters the multi-tower SF6 gas distillation and purification equipment 30 through the finished gas channel, and the separated tail gas enters the pressure swing adsorption equipment 40. Afterwards, the molecular sieve in the pressure swing adsorption equipment 40 can adsorb the SF6 in the separated tail gas, and the regenerated SF6 gas enters the mixed gas membrane separation equipment 20 through the regenerated SF6 gas channel for re-separation, and other gases in the separated tail gas are discharged through the outlet of the pressure swing adsorption equipment 40.

[0048] It can be seen that the degree of purification of SF6 gas can be improved as much as possible through the treatment process of the SF6 gas entering the sulfur hexafluoride and mixed gas purification device.

[0049] Gas membrane separation is mainly achieved based on the different relative transfer rates of each component in the mixed raw gas through the membrane under the pressure. At present, there are two common gas separation mechanisms through the membrane: one is the microporous diffusion mechanism of the gas through the porous membrane; the other is the dissolution-diffusion mechanism of the gas through the non-porous membrane. The separation of SF6 gas and N2 adopts the permeation mechanism of non-porous membrane (also known as homogeneous membrane). Under the action of pressure, the gas components first dissolve on the surface of the membrane on the high-pressure side of the membrane, and then adsorb, dissolve, diffuse, desolventize, and escape along the concentration gradient in the membrane, and transfer to the other side of the membrane to achieve the separation of the two component gases.

[0050] In order to increase the gas permeation of organic non-porous membranes, it is necessary to increase the permeability coefficient, pressure difference and membrane surface area and reduce the membrane thickness. Here, in order to improve the separation efficiency of the mixed gas, a membrane with a larger permeability coefficient difference can be selected, that is, it is hoped that the membrane has a higher selectivity and a larger permeability for a certain component A in the mixed gas, and only a lower selectivity and a smaller permeability for the other component B, so as to obtain a more satisfactory purification effect.

[0051] In order to increase the membrane separation surface area, the structure of the mixed gas membrane separation equipment 20 is improved from the plate-and-frame type to the spiral-wound type, the tube type and even the hollow fiber type. With each structural improvement, the separation surface area increases geometrically, and the hollow fiber separation membrane has the largest surface area.

[0052] In some embodiments, see Figure 2 The mixed gas membrane separation device 20 may include a first filter 21, a compressor 22, a second filter 23, a primary membrane 24 and a secondary membrane 25 which are connected in sequence.

[0053] The permeate side of the secondary membrane 25 is connected to the inlet of the compressor 22, the inlet of the first filter 21 is connected to the third port of the first rotary valve 10, and the outlet of the secondary membrane 25 is connected to the multi-tower SF6 gas distillation and purification equipment 30 through the outlet of the finished gas channel. The filtering accuracy of the second filter 23 is higher than that of the first filter 21.

[0054] Exemplarily, the mixed gas membrane separation device 20 may further include a molecular sieve 26 and a heater 27. The molecular sieve 26 is located between the compressor 22 and the second filter 23, and the compressor 22, the molecular sieve 26 and the second filter 23 are sequentially connected. The heater 27 is located between the second filter 23 and the primary membrane 24, and the second filter 23, the heater 27 and the primary membrane 24 are sequentially connected.

[0055] Exemplarily, the number of compressors 22 may be at least two, and the at least two compressors jointly provide the pressure required for gas separation, which is less than or equal to 1.2 MPa. The second filter 23 is a filter capable of filtering dust particles with a diameter greater than 0.005 μm.

[0056] Illustratively, heater 27 is capable of heating the gas to 45°C.

[0057] The working process of the mixed gas membrane separation device 20 is:

[0058] First, the mixed insulating gas enters from the air inlet and is filtered by the first filter 21 to remove impurities such as decomposition products and moisture in the adsorbed gas.

[0059] Secondly, the gas passes through a large flow compressor 22 (single or multiple compressors can be selected according to the actual flow) to provide the pressure required for mixed gas separation. The pressure cannot exceed 1.2Mpa, because according to the membrane design, the pressure mainly determines the gas separation membrane flow and the mixed gas separation effect. When the pressure is too high, the gas separation membrane flow will increase, while the gas separation quality will decrease. If the pressure is lower than 1.2Mpa, the gas separation membrane flow will decrease, but the corresponding gas separation quality will increase.

[0060] Then, the gas is filtered through the second filter 23. Since the membrane has high requirements on the quality of the intake air, that is, the particle size of the dust particles in the mixed gas is less than 0.01 μm, the second filter is selected as a precision filter to ensure the filtering accuracy.

[0061] Finally, according to the gas temperature conditions when the mixed gas membrane separation device 20 is running, the heating temperature of the heater 27 is adjusted. When the gas passes through the heater 27, the gas inlet temperature can reach 45° C., ensuring the gas treatment quality.

[0062] Entering the mixed gas rapid separation module (i.e., the primary membrane 24 and the secondary membrane 25), the gas automatically dissolves, diffuses, and flows due to the pressure difference. After the gas is filtered by the primary membrane 24, the gas on the permeate side of the primary membrane 24 contains 0.91% SF6, and the rest is N2, which cannot meet the direct emission standard and needs to be cached and processed. The SF6 volume concentration of the gas at the outlet of the primary membrane 24 is 71.76%, and then it continues to enter the secondary membrane 25. The volume content of SF6 in the permeate side of the secondary membrane 25 is 4.84%, which can be directly connected to the inlet of the compressor 22 through a pipeline, and continue to circulate and separate with the gas; the volume ratio of SF6 at the outlet of the secondary membrane 25 is 90.93%, and it enters the multi-tower SF6 gas distillation and purification equipment 30 for gas purification.

[0063] Taking advantage of the difference in volatility of each component in the mixture, the gas and liquid phases are brought into reverse multi-stage contact through the reflux of the liquid and gas phases. Under the constraints of thermal energy drive and phase equilibrium, the volatile component (light component) is continuously transferred from the liquid phase to the gas phase, while the non-volatile component migrates from the gas phase to the liquid phase, so that the mixture is continuously separated. This process is called distillation. In this process, heat transfer and mass transfer processes are carried out simultaneously, which belongs to mass transfer process control.

[0064] The raw materials enter the tower from the appropriate position in the middle of the tower, and the tower is divided into two sections. The upper section is the rectification section, which does not contain feed, and the lower section contains the feed plate as the stripping section. The condenser provides liquid reflux from the top of the tower, and the reboiler provides gas reflux from the bottom of the tower. Gas and liquid reflux is an important feature of distillation. In the process of the gas phase rising in the rectification section, the light components in the gas phase are continuously refined, and the concentration in the gas phase is continuously increased, and the light component products are obtained at the top of the tower. In the stripping section, the light components are continuously stripped out during the process of the liquid phase falling, so that the heavy components are continuously concentrated in the liquid phase, and the heavy component products are obtained at the bottom of the tower. The biggest difference between the rectification process and other distillation processes is that high-purity liquid and gas reflux are provided at both ends of the tower at the same time, which provides the necessary conditions for mass transfer for the rectification process. Providing high-purity reflux can always ensure a certain mass transfer driving force when achieving high-purity separation for distillation under the same theoretical plate conditions. Therefore, as long as there are enough theoretical plates and the reflux is large enough, it is possible to obtain a high-purity light component product at the top of the tower and a high-purity heavy component product at the bottom of the tower.

[0065] Cryogenic distillation usually uses mechanical methods to compress and cool the gas, and then uses the difference in boiling points of different gases to separate different gases. The temperature of cryogenic distillation is generally around -15℃ to -5℃, and the boiling points of SF6 gas and Air gas are different. When SF6 gas is at 1.2Mpa and the temperature is 0℃, it can be liquefied, so SF6 gas can be separated from air and fluorocarbons.

[0066] In some embodiments, see Figure 3 The multi-tower SF6 gas distillation and purification equipment 30 may include a refrigerator 31, a reboiler (not shown), a sulfur hexafluoride liquid storage unit 32 and multiple distillation and purification towers 33.

[0067] The multiple distillation and purification towers 33 are connected in sequence, and the distillation and purification towers at both ends are respectively provided with an air inlet and an exhaust port, the air inlet is connected to the second port of the first rotary valve 10, and the exhaust port is connected to the mixed gas membrane separation device 20 through the exhaust gas channel. The refrigerator 31 provides liquid phase reflux from the top of the multiple distillation and purification towers 33, and the reboiler provides gas phase reflux from the bottom of the multiple distillation and purification towers 33. The bottoms of the multiple distillation and purification towers 33 are all connected to the sulfur hexafluoride liquid storage unit 32.

[0068] Exemplarily, each of the plurality of distillation and purification towers 33 is provided with a vertically arranged refrigeration coil 34 , and each refrigeration coil 34 is connected to a refrigerator 31 .

[0069] For example, the number of the plurality of rectification and purification towers 33 is three.

[0070] Artificial zeolite is used as the material for adsorbing gas in pressure swing adsorption technology. It is a molecular sieve that prevents some gas molecules from passing through, while allowing other gas molecules to pass through.

[0071] The principle of pressure swing adsorption technology is: when the air pressure is relatively high, artificial zeolite adsorbs a certain gas; and when the air pressure is relatively low, the adsorbed gas is released. In other words, when the air pressure changes from high to low, the artificial zeolite can be recycled. At present, the pressure swing adsorption method has been commercially applied to separate oxygen from the air. Finding a suitable artificial zeolite can separate SF6 gas from the SF6 / AIR mixed gas. First, it is necessary to select a suitable artificial zeolite, and Na-X type (effective micropore diameter is 1nm) artificial zeolite is used as the adsorption material. It can adsorb a large number of SF6 molecules, but almost no N2 molecules. The content of SF6 gas in the tail gas after membrane separation is between 0.5% and 1%, which cannot be emptied. It is necessary to use pressure swing adsorption to adsorb the SF6 gas in the tail gas.

[0072] In some embodiments, see Figure 4 The pressure swing adsorption device 40 may include a second rotary valve 41 , a first molecular sieve group 42 , a second molecular sieve group 43 , a third rotary valve 44 and a fourth rotary valve 45 .

[0073] The first port of the second rotary valve 41 is connected to the outlet of the mixed gas membrane separation device 20 , the second port of the second rotary valve 41 is connected to the first port of the first molecular sieve group 42 , and the third port of the second rotary valve 41 is connected to the first port of the second molecular sieve group 42 .

[0074] The second port of the first molecular sieve group 42 is communicated with the second port of the third rotary valve 44 , the second port of the second molecular sieve group 43 is communicated with the third port of the third rotary valve 44 , and the first port of the third rotary valve 44 is connected to the external environment.

[0075] The first port of the fourth rotary valve 45 is connected to the inlet of the mixed gas membrane separation device 20 , the second port of the fourth rotary valve 45 is connected to the first port of the first molecular sieve group 42 , and the third port of the fourth rotary valve 45 is connected to the first port of the second molecular sieve group 43 .

[0076] For example, the first molecular sieve group and the second molecular sieve group may each include at least two molecular sieves connected in sequence.

[0077] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A sulfur hexafluoride and mixed gas purification device, characterized in that: include: The first rotary valve, mixed gas membrane separation equipment, multi-tower SF6 gas distillation and purification equipment, pressure swing adsorption equipment and liquid filling equipment; The first port of the first rotary valve is connected to the gas to be purified, the second port is connected to the inlet of the multi-tower SF6 gas distillation and purification equipment, and the third port is connected to the inlet of the mixed gas membrane separation equipment; The outlet of the mixed gas membrane separation device is connected to the pressure swing adsorption device, and the outlet of the pressure swing adsorption device is connected to the external environment; wherein a regeneration SF6 gas channel is provided between the pressure swing adsorption device and the mixed gas membrane separation device, one end of the regeneration SF6 gas channel is connected to the inlet of the mixed gas membrane separation device, and the other end is connected to the middle of the pressure swing adsorption device; The outlet of the multi-tower SF6 gas distillation and purification equipment is connected to the liquid filling equipment, and the liquid filling equipment is connected to the SF6 cylinder; Among them, a finished gas channel and an exhaust gas channel are arranged between the mixed gas membrane separation equipment and the multi-tower SF6 gas distillation and purification equipment; the inlet of the finished gas channel is connected to the mixed gas membrane separation equipment, and the outlet of the finished gas channel is connected to the multi-tower SF6 gas distillation and purification equipment; the inlet of the exhaust gas channel is connected to the multi-tower SF6 gas distillation and purification equipment, and the outlet of the exhaust gas channel is connected to the mixed gas membrane separation equipment.

2. The sulfur hexafluoride and mixed gas purification device according to claim 1, characterized in that: The mixed gas membrane separation device comprises a first filter, a compressor, a second filter, a primary membrane and a secondary membrane which are connected in sequence; The permeate side of the secondary membrane is communicated with the inlet of the compressor, the inlet of the first filter is communicated with the third port of the first rotary valve, and the outlet of the secondary membrane is communicated with the multi-tower SF6 gas distillation and purification equipment through the outlet of the finished gas channel; Wherein, the filtering accuracy of the second filter is higher than the filtering accuracy of the first filter.

3. The sulfur hexafluoride and mixed gas purification device according to claim 2, characterized in that: The mixed gas membrane separation device also includes a molecular sieve and a heater; The molecular sieve is located between the compressor and the second filter, and the compressor, the molecular sieve and the second filter are connected in sequence; The heater is located between the second filter and the primary membrane, and the second filter, the heater and the primary membrane are connected in sequence.

4. The sulfur hexafluoride and mixed gas purification device according to claim 2, characterized in that: The number of the compressors is at least two, and the at least two compressors jointly provide the pressure required for gas separation, which is less than or equal to 1.2 Mpa; The second filter is a filter capable of filtering out dust particles with a diameter greater than 0.005 μm.

5. The sulfur hexafluoride and mixed gas purification device according to claim 3, characterized in that: The heater heated the gas to 45°C.

6. The sulfur hexafluoride and mixed gas purification device according to claim 1, characterized in that: The multi-tower SF6 gas distillation and purification equipment includes a refrigerator, a reboiler, a sulfur hexafluoride liquid storage unit and a plurality of distillation and purification towers; The multiple distillation and purification towers are connected in sequence, and the distillation and purification towers at both ends are respectively provided with an air inlet and an exhaust port, the air inlet is connected to the second port of the first rotary valve, and the exhaust port is connected to the mixed gas membrane separation device through the exhaust gas channel; The refrigerator provides liquid reflux from the tops of the multiple distillation and purification towers, and the reboiler provides gas reflux from the bottoms of the multiple distillation and purification towers; The bottoms of the multiple distillation and purification towers are all connected to the sulfur hexafluoride liquid storage unit.

7. The sulfur hexafluoride and mixed gas purification device according to claim 6, characterized in that: The number of the multiple distillation and purification towers is three.

8. The sulfur hexafluoride and mixed gas purification device according to claim 6, characterized in that: The multiple distillation and purification towers are each provided with a vertically arranged refrigeration coil, and each refrigeration coil is connected to the refrigeration machine.

9. The sulfur hexafluoride and mixed gas purification device according to claim 1, characterized in that: The pressure swing adsorption device comprises a second rotary valve, a first molecular sieve group, a second molecular sieve group, a third rotary valve and a fourth rotary valve; The first port of the second rotary valve is communicated with the outlet of the mixed gas membrane separation device, the second port of the second rotary valve is communicated with the first port of the first molecular sieve group, and the third port of the second rotary valve is communicated with the first port of the second molecular sieve group; The second port of the first molecular sieve group is in communication with the second port of the third rotary valve, the second port of the second molecular sieve group is in communication with the third port of the third rotary valve, and the first port of the third rotary valve is connected to the external environment; The first port of the fourth rotary valve is connected to the inlet of the mixed gas membrane separation device, the second port of the fourth rotary valve is connected to the first port of the first molecular sieve group, and the third port of the fourth rotary valve is connected to the first port of the second molecular sieve group.

10. The sulfur hexafluoride and mixed gas purification device according to claim 9, characterized in that: The first molecular sieve group and the second molecular sieve group each include at least two molecular sieves connected in sequence.

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