Non-equilibrium Concentration SF6 Mixed Gas Recovery and Treatment Equipment and Method in Electrical Equipment

Abstract

The present invention discloses a non-equilibrium concentration SF6 mixed gas recovery and treatment device and method in an electrical equipment, belonging to the technical field of SF6 gas recovery. The recovery and treatment device includes: an electrical equipment connecting pipe, an external recovery device, an inlet connecting pipe, an outlet connecting pipe, a TSA tower, an exhaust gas discharge pipe, an air cooler, a PID controller and a circulation fan; the electrical equipment connecting pipe is connected to the electrical equipment gas chamber and the first connecting pipe, the inlet connecting pipe is connected to the inlet of the external recovery device and the first connecting pipe, the outlet of the external recovery device is connected to the outlet connecting pipe, and the outlet connecting pipe is connected to the TSA tower; the TSA tower is connected to the exhaust gas discharge pipe; the inlet connecting pipe is also connected to the air cooler, and the SF6 after being analyzed and mixed evenly is transported to the external recovery device for recovery, separation and storage. The present invention enables the recovered nitrogen and SF6 mixed gas to be quickly and evenly mixed, ensures the effect of nitrogen and SF6 membrane separation, avoids the emission of SF6 into the atmosphere, and fully ensures the SF6 recovery rate.

Description

Technical Field

[0001] This application belongs to the technical field of SF6 gas recovery, and particularly relates to a recovery and treatment device and method for SF6 mixed gas with non-uniform concentration in electrical equipment. Background Art

[0002] At present, with the rapid development of social economy, transmission and transformation substations are continuously built and put into operation, and the inventory of transmission and transformation equipment continues to increase. SF6 (sulfur hexafluoride), as an excellent insulating and arc-extinguishing medium, is widely used in transmission and transformation equipment. SF6 has an extremely strong greenhouse effect, more than 23,000 times that of carbon dioxide. When overhauling and decommissioning transmission and transformation equipment, SF6 must be recovered to avoid discharging the high greenhouse effect gas SF6 into the atmosphere. At present, when the absolute pressure of SF6 in transmission and transformation equipment is recovered to below a certain pressure (generally 50 kPa), due to technical limitations, the existing recovery device cannot completely recover SF6, with a residue of more than 3%. The residual SF6 will be discharged into the air, polluting the environment. Therefore, the SF6 recovery rate must reach more than 96.5%.

[0003] In order to achieve this recovery rate, technicians inject nitrogen into the transmission and transformation equipment, dilute SF6 and then recover it. However, the concentration of the diluted SF6 gas is low, and the nitrogen filled in a short time cannot be mixed evenly with SF6 only by diffusion. Especially in large air chambers such as circuit breakers and busbars, it takes a long time to mix evenly. Using the existing SF6 recovery device to directly recover the SF6-nitrogen mixture gas, SF6 cannot be separated from nitrogen. Because of the presence of nitrogen, the mixture gas cannot be liquefied, and on-site storage requires large-volume storage tanks or more cylinders. The frequent replacement and handling of storage tanks and cylinders also add a large amount of workload and safety hazards to on-site emergency repair operations.

[0004] To separate SF6 from nitrogen, a recovery and treatment device with an SF6 membrane separation device is required. Due to the uneven concentration of SF6 in the gas chamber of electrical equipment and the dynamic change of SF6 concentration during the recovery process, the membrane separation device cannot establish a dynamic balance relationship of concentration, pressure, flow rate, and temperature for SF6 gas with different concentrations during operation. As a result, during the recovery and separation process, the SF6 content on the permeate side of SF6 is still relatively high, and the discharged gas cannot meet the discharge requirements, and a certain amount of SF6 will still be discharged into the air, causing environmental pollution.

[0005] Therefore, there is an urgent need for a recovery and treatment device and method for SF6 mixed gas with non-uniform concentration to achieve the recovery and effective separation of SF6-nitrogen mixture gas with non-uniform concentration and solve the problems in the nitrogen injection recovery process. Summary of the Invention

[0006] The present invention aims to solve the problem of recycling dynamic concentration SF6 mixed gas during the nitrogen injection recycling process, and provides a non-equilibrium concentration SF6 gas recycling and treatment device and method for electrical equipment. This method can transform non-equilibrium low-concentration SF6 gas into an equilibrium state, and can control its concentration within the appropriate treatment range of about 30% of the current market's SF6 / N2 membrane separation device, meeting the operating conditions of on-site mixed gas treatment equipment.

[0007] The present invention adopts the following technical solutions.

[0008] The first aspect of the present invention discloses a non-equilibrium concentration SF6 mixed gas recycling and treatment device for electrical equipment, including: an electrical equipment connecting pipe, an external recycling device, an inlet connecting pipe, an outlet connecting pipe, a TSA (Temperature Swing Adsorption) tower, an exhaust gas discharge pipe, an air cooler, a PID controller (Proportion Integration Differentiation), and a circulation fan;

[0009] One end of the electrical equipment connecting pipe is connected to the gas chamber of the electrical equipment, and the other end is connected to the first connecting pipe. One end of the inlet connecting pipe is connected to the inlet of the external recycling device, and the other end is connected to the first connecting pipe. The outlet of the external recycling device is connected to the outlet connecting pipe, and the outlet connecting pipe is connected to the TSA tower, for transporting the SF6 mixed gas in the gas chamber of the electrical equipment to the TSA tower;

[0010] The TSA tower is connected to the PID controller, for recycling and treating the SF6 mixed gas; the TSA tower is connected to the circulation fan, for mixing the SF6 mixed gas analyzed in the TSA tower; the TSA tower is connected to the exhaust gas discharge pipe, for discharging the remaining nitrogen after recycling SF6;

[0011] The inlet connecting pipe is also connected to the air cooler, for cooling the high-temperature SF6 analyzed in the TSA tower, and transporting the evenly mixed SF6 after analysis to the external recycling device for recycling, separation, and storage.

[0012] Preferably, a first electric proportional regulating valve is arranged between the electrical equipment connecting pipe and the first connecting pipe, and a first solenoid valve and a second connecting pipe are connected between the outlet connecting pipe and the TSA tower.

[0013] Preferably, a precision filter is arranged between the second connecting pipe and the TSA tower. The precision filter is installed at the lower inlet of the TSA tower. The precision filter can filter solid particles to prevent the gas analyzed from the TSA tower from containing solid particles such as dust, which may damage components after flowing out.

[0014] Preferably, a temperature transmitter, an in-TSA tower condenser, a pressure transmitter, and an in-TSA tower heater are installed on the TSA tower;

[0015] The in-TSA tower condenser is connected to a refrigeration unit to form a cooling cycle; one end of a third connecting pipe is connected to the TSA tower outlet, and the other end is connected to a second electric proportional regulating valve, and an exhaust gas discharge pipe is connected to the second electric proportional regulating valve; one end of a seventh connecting pipe is connected to the inlet of a circulation fan, and one end is connected to the third connecting pipe; one end of an eighth connecting pipe is connected to the circulation fan, and the other end is connected to a fourth solenoid valve, and one end of a ninth connecting pipe is connected to the bottom interface of the TSA tower, and the other end is connected to the fourth solenoid valve.

[0016] Preferably, one end of the second connecting pipe is connected to one end of the fourth connecting pipe, and the other end of the fourth connecting pipe is connected to a second solenoid valve; one end of a fifth connecting pipe is connected to the second solenoid valve, and the other end is connected to an air cooler; one end of a sixth connecting pipe is connected to the air cooler, and the other end is connected to a third solenoid valve, and the third solenoid valve is connected to an inlet connecting pipe.

[0017] Preferably, the temperature transmitter is connected to a PID controller through a temperature data transmission line; the pressure transmitter is connected to the PID controller through a pressure data transmission line; the PID controller is connected to a first electric proportional regulating valve through a first control line; the second electric proportional regulating valve is connected to the PID controller through a second control line.

[0018] The second aspect of the present invention discloses a method for recovering and treating non-uniform concentration SF6 mixed gas in electrical equipment, based on the above-mentioned non-uniform concentration SF6 mixed gas recovery and treatment equipment for electrical equipment, including the following steps:

[0019] Step 1: Connect the electrical equipment gas chamber to the connecting pipe of the electrical equipment gas chamber interface, and connect the external recovery device to the inlet connecting pipe and the outlet connecting pipe;

[0020] Step 2: Start the refrigeration unit to lower the internal temperature of the TSA tower, start the direct recovery function process of the external recovery device, and when the temperature transmitter reaches the preset temperature value, transmit the temperature value to the PID controller, and the PID controller adjusts the opening of the first electric proportional regulating valve to control the recovery gas flow rate, so that the internal working temperature of the TSA tower is stabilized within the set range;

[0021] Step 3: The gas in the electrical equipment enters the inside of the TSA tower through the first electric proportional regulating valve, and the non-uniform concentration SF6 gas is adsorbed and retained in the TSA tower. When the pressure transmitter monitors that the internal pressure of the TSA tower reaches the set value, transmit the pressure value to the PID controller, and the PID controller adjusts the opening of the second electric proportional regulating valve to discharge the residual nitrogen gas adsorbed in the TSA tower through the second electric proportional regulating valve;

[0022] Step 4, after the gas in the electrical equipment is recovered, turn off the refrigeration unit, turn on the heater in the TSA tower, close the direct recovery process of the external recovery device, turn on the fourth solenoid valve, and turn on the circulation fan. The circulation fan continuously circulates the SF6 gas desorbed from the TSA tower and the residual nitrogen gas in the tower, so that the SF6 gas and the residual nitrogen gas are evenly mixed.

[0023] Step 5, when the detection value of the temperature transmitter reaches the set desorption temperature, maintain this temperature value and continue to circulate. Then turn on the air cooler and the recovery and separation function of the external recovery device, and recover, separate and store the evenly mixed SF6 gas retained and desorbed in the TSA tower through the external recovery device.

[0024] Step 6, when the internal pressure value of the TSA tower is lower than the set value, turn off all electrical equipment and end the recovery and separation work of the non-equilibrium concentration SF6 mixed gas in the electrical equipment.

[0025] Preferably, step 2 specifically includes: starting the refrigeration unit to reduce the internal temperature of the TSA tower through the condenser in the TSA tower, starting the direct recovery function process of the external recovery device, turning on the first solenoid valve. When the temperature transmitter reaches the preset temperature value, transmit the temperature value to the PID controller through the temperature data transmission line. The PID controller adjusts the opening of the first electric proportional regulating valve according to the preset range of the temperature value and through the first control line to control the recovery gas flow rate, so that the internal working temperature of the TSA tower is stabilized within the set range.

[0026] Preferably, step 3 specifically includes: the gas in the electrical equipment passes through the electrical equipment connecting pipe, the first electric proportional regulating valve, the first connecting pipe, the inlet connecting pipe, the external recovery device, the outlet connecting pipe, the first solenoid valve, the second connecting pipe, and the precision filter and enters the inside of the TSA tower. The non-equilibrium concentration SF6 gas is adsorbed and retained by the SF6 adsorbent filled in the TSA tower under low temperature conditions. When the pressure transmitter monitors that the internal pressure of the TSA tower reaches the set value, transmit the pressure value to the PID controller through the pressure data transmission line. The PID controller adjusts the opening of the second electric proportional regulating valve according to the preset range of the pressure value and through the second control line, and discharges the residual nitrogen gas adsorbed in the TSA tower through the second electric proportional regulating valve.

[0027] Preferably, step 4 specifically includes: after the gas in the electrical equipment is recovered, turn off the refrigeration unit, turn on the heater in the TSA tower, turn off the first solenoid valve, turn off the second electric proportional regulating valve and lock it to prohibit gas discharge, close the direct recovery process of the external recovery device, turn on the fourth solenoid valve, and turn on the circulation fan. The circulation fan continuously circulates the SF6 gas desorbed from the TSA tower and the residual nitrogen gas in the tower, so that the SF6 gas and the residual nitrogen gas are evenly mixed.

[0028] The present invention solves the problem of recycling non-uniform concentration SF6 mixed gas, designs a recycling and treatment device for non-uniform concentration SF6 mixed gas, connects it to SF6 electrical equipment. During recycling, the diluted non-uniform concentration SF6 mixed gas is recycled into the TSA tower by the recycling and treatment device for non-uniform concentration SF6 mixed gas for low-temperature adsorption and enrichment. After the gas in the electrical equipment is recycled, SF6 is desorbed by heating and mixed with the remaining nitrogen to form a SF6 mixed medium with uniform concentration. The raw gas with dynamic concentration change during recycling is transformed into a SF6 mixed medium with fixed high concentration, which is convenient for the external recycling device to establish stable material balance parameters when using the membrane separation treatment method, avoiding the excessive content of SF6 (500 ppm) in the separated nitrogen due to the fluctuation of the raw gas concentration, and also reducing the storage volume required for directly recycling the mixed gas. During the process of nitrogen injection dilution and SF6 recycling, the SF6 emission and gas storage volume are reduced, and the requirement of high recovery rate in the SF6 recycling work is successfully implemented.

[0029] Compared with the prior art, the beneficial effects of the present invention at least include:

[0030] (1) The present invention makes the recycled nitrogen and SF6 mixed gas quickly and evenly mixed, ensures the effect of nitrogen and SF6 membrane separation, and makes SF6 completely separated as much as possible to avoid discharging into the atmosphere.

[0031] (2) By improving the SF6 separation effect, the present invention fully ensures the SF6 recovery rate and reduces the impact of the high greenhouse gas SF6 on the ecological environment.

[0032] (3) The present invention enables effective separation of SF6 and nitrogen at the substation site, without the need to store, transport and reprocess the mixed gas, saving manpower, material resources and financial resources. Description of the Drawings

[0033] Figure 1 is a recycling and treatment device for non-uniform concentration SF6 mixed gas in an electrical equipment;

[0034] In the figure: 1. Electrical equipment connecting pipe; 2. First electric proportional regulating valve; 3. First connecting pipe; 4. Inlet connecting pipe; 5. Outlet connecting pipe; 6. First solenoid valve; 7. Second connecting pipe; 8. Precision filter; 9. TSA tower; 10. Temperature transmitter; 11. In-tower condenser of TSA tower; 12. Pressure transmitter; 13. In-tower heater of TSA tower; 14. Third connecting pipe; 15. Second electric proportional regulating valve; 16. Tail gas discharge pipe; 17. Fourth connecting pipe; 18. Second solenoid valve; 19. Fifth connecting pipe; 20. Air cooler; 21. Sixth connecting pipe; 22. Third solenoid valve; 23. Refrigeration unit; 24. Temperature data transmission line; 25. First control line; 26. Pressure data transmission line; 27. Second control line; 28. PID controller; 29. Seventh connecting pipe; 30. Circulation fan; 31. Eighth connecting pipe; 32. Fourth solenoid valve; 33. Ninth connecting pipe; 34. External recovery device. Detailed implementation mode

[0035] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. The embodiments described in this application are only a part of the embodiments of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0036] Embodiment 1 of the present invention provides a non-equilibrium concentration SF6 mixed gas recovery and treatment device for electrical equipment, including: electrical equipment connecting pipe 1, first electric proportional regulating valve 2, first connecting pipe 3, inlet connecting pipe 4, outlet connecting pipe 5, first solenoid valve 6, second connecting pipe 7, precision filter 8, TSA tower 9, temperature transmitter 10, in-tower condenser 11 of TSA tower, pressure transmitter 12, in-tower heater 13 of TSA tower, third connecting pipe 14, second electric proportional regulating valve 15, tail gas discharge pipe 16, fourth connecting pipe 17, second solenoid valve 18, fifth connecting pipe 19, air cooler 20, sixth connecting pipe 21, third solenoid valve 22, refrigeration unit 23, temperature data transmission line 24, first control line 25, pressure data transmission line 26, second control line 27, PID controller 28, seventh connecting pipe 29, circulation fan 30, eighth connecting pipe 31, fourth solenoid valve 32, ninth connecting pipe 33, external recovery device 34.

[0037] The external recovery device 34 has the functions of directly recovering the SF6 mixed gas and recovering and separating the SF6 mixed gas with balanced concentration.

[0038] One end of the connecting pipe 1 of the electrical equipment is connected to the gas chamber interface of the electrical equipment, and the other end is connected to the first electro-proportional regulating valve 2; one end of the first connecting pipe 3 is connected to the first electro-proportional regulating valve 2, and the other end is connected to the inlet connecting pipe 4 and is also connected to the third solenoid valve 22; one end of the inlet connecting pipe 4 is connected to the inlet of the external recovery device 34, and the other end is connected to the first connecting pipe 3 and is also connected to the third solenoid valve 22; one end of the outlet connecting pipe 5 is connected to the outlet of the external recovery device 34, and the other end is connected to the first solenoid valve 6; one end of the second connecting pipe 7 is connected to the first solenoid valve 6, and the other end is connected to the precision filter 8; the precision filter 8 is installed at the lower inlet of the TSA tower 9.

[0039] The precision filter 8 can filter solid particles to prevent solid particles such as dust from being contained in the gas analyzed from the TSA tower 9, so as not to damage the components after flowing out.

[0040] A temperature transmitter 10, an in-TSA condenser 11, a pressure transmitter 12 and an in-TSA heater 13 are installed on the TSA tower 9; the in-TSA condenser 11 is connected to the refrigeration unit 23 to form a cooling cycle; one end of the third connecting pipe 14 is connected to the outlet of the TSA tower 9, and the other end is connected to the second electro-proportional regulating valve 15, and the tail gas discharge pipe 16 is connected to the second electro-proportional regulating valve 15; one end of the seventh connecting pipe 29 is connected to the inlet of the circulation fan 30, and one end is connected to the third connecting pipe 14; one end of the eighth connecting pipe 31 is connected to the circulation fan 30, and the other end is connected to the fourth solenoid valve 32; one end of the ninth connecting pipe 33 is connected to the bottom interface of the TSA tower 9, and the other end is connected to the fourth solenoid valve 32.

[0041] One end of the fourth connecting pipe 17 is connected to the second solenoid valve 18, and the other end is connected to the second connecting pipe 7; one end of the fifth connecting pipe 19 is connected to the second solenoid valve 18, and the other end is connected to the air cooler 20; one end of the sixth connecting pipe 21 is connected to the air cooler 20, and the other end is connected to the third solenoid valve 22; the temperature data transmission line 24, the pressure data transmission line 26, the first control line 25 and the second control line 27 are all connected to the PID controller 28.

[0042] Embodiment 2 of the present invention provides a method for processing and recovering non-uniform concentration SF6 mixed gas in electrical equipment, including the following steps:

[0043] Step 1, connect the gas chamber of the electrical equipment to the connecting pipe 1 of the electrical equipment, and connect the external recovery device 34 to the inlet connecting pipe 4 and the outlet connecting pipe 5.

[0044] Step 2: Start the refrigeration unit 23 to lower the internal temperature of the TSA tower 9, and start the direct recovery function process of the external recovery device 34. When the temperature transmitter 10 reaches the preset temperature value, the temperature value is transmitted to the PID controller 28. The PID controller 28 adjusts the opening degree of the first electric proportional regulating valve 2 to control the recovery gas flow rate, ensuring that the internal working temperature of the TSA tower 9 is stable within the set range.

[0045] Specifically, Step 2 includes: starting the refrigeration unit 23 to lower the internal temperature of the TSA tower 9 through the internal condenser 11 of the TSA tower, starting the direct recovery function process of the external recovery device 34, opening the first solenoid valve 6. When the temperature transmitter 10 reaches the preset temperature value T0, the temperature value T is transmitted to the PID controller 28 through the temperature data transmission line 24. The PID controller 28 adjusts the opening degree of the first electric proportional regulating valve 2 according to the preset range (T1~T2) of the temperature value T and through the first control line 25 to control the recovery gas flow rate, ensuring that the internal working temperature of the TSA tower 9 is stable within the set range (T1~T2).

[0046] In a preferred but non-limiting embodiment of the present invention, the preset range (T1~T2) of the temperature value T is -15°C to -5°C.

[0047] The preset temperature value T0 is -10°C.

[0048] Set the adsorption working temperature condition of the TSA tower 9. The temperature value monitored by the temperature transmitter 10 in real time is transmitted to the PID controller 28. The PID controller 28 then transmits the control feedback signal to the opening degree of the first electric proportional regulating valve 2 according to the set temperature value to control the recovery flow rate. The high temperature limit set value T2 can avoid the internal temperature of the TSA tower 9 being too high and the adsorption working efficiency being low due to the increase in heat exchange caused by too large a recovery flow rate. The low temperature limit set value T1 can avoid the system continuously reducing the flow rate to meet the low temperature condition, reducing the recovery rate and affecting the on-site working efficiency.

[0049] Step 3: The gas in the electrical equipment enters the interior of the TSA tower 9 through the first electric proportional regulating valve 2. The non-uniform concentration SF6 gas is adsorbed and retained in the TSA tower 9. When the pressure transmitter 12 monitors that the internal pressure of the TSA tower 9 reaches the set value, the pressure value P is transmitted to the PID controller 28. The PID controller 28 adjusts the opening degree of the second electric proportional regulating valve 15 to discharge the residual nitrogen gas in the TSA tower after adsorption through the second electric proportional regulating valve 15.

[0050] Step 3 specifically includes that the gas in the electrical equipment passes through the electrical equipment connecting pipe 1, the first electric proportional regulating valve 2, the first connecting pipe 3, the external recovery device 34, the inlet connecting pipe 4, the outlet connecting pipe 5, the first solenoid valve 6, the second connecting pipe 7, and the precision filter 8 and enters the TSA tower 9. The non-uniform concentration SF6 gas is adsorbed and retained by the SF6 adsorbent filled in the TSA tower under low-temperature conditions. When the pressure transmitter 12 monitors that the internal pressure of the TSA tower 9 reaches the set value P0, the pressure value P is transmitted to the PID controller 28 through the pressure data transmission line 26. The PID controller 28 adjusts the opening of the second electric proportional regulating valve 15 according to the preset range (P1~P2) of the pressure value P and discharges a large amount of nitrogen remaining after adsorption in the TSA tower through the second electric proportional regulating valve 15;

[0051] In a preferred but non-limiting embodiment of the present invention, the preset range (P1~P2) of the pressure value P is 1 MPa to 1.5 MPa;

[0052] The set value P0 is 1.25 MPa;

[0053] Set the adsorption working pressure control conditions of the TSA tower 9 to avoid the pressure change caused by the temperature fluctuation inside the low-temperature TSA tower 9. Since the high pressure during the operation of the TSA tower 9 can increase the adsorption amount, and the pressure reduction will reduce the adsorption amount, the process of changing from high pressure to low pressure will produce an analytical phenomenon, resulting in the excessive SF6 content in the gas discharged into the air. Therefore, in the present invention, the internal working pressure of the TSA tower 9 is monitored in real time by the pressure transmitter 12, and the pressure monitoring value is transmitted to the PLD controller 28 in real time. The control feedback signal is sent to the second electric proportional regulating valve 15 through the PLD controller, and the discharge gas flow rate is controlled by controlling the second electric proportional regulating valve 15 to control the stability of the pressure inside the TSA tower.

[0054] Step 4, after the gas in the electrical equipment is recovered, turn off the refrigeration unit 23, turn on the heater 13 inside the TSA tower, turn off the direct recovery process of the external recovery device 34, turn on the fourth solenoid valve 32, and turn on the circulation fan 30. The circulation fan 30 continuously circulates the SF6 desorbed from the TSA tower and the remaining nitrogen in the tower to make the SF6 and the remaining nitrogen evenly mixed;

[0055] Step 4 specifically includes that after the gas in the electrical equipment is recovered, turn off the refrigeration unit 23, turn on the heater 13 inside the TSA tower, turn off the first solenoid valve 6, turn off the second electric proportional regulating valve 15 and lock it to prohibit gas discharge, turn off the direct recovery process of the external recovery device 34, turn on the fourth solenoid valve 32, and turn on the circulation fan 30. The circulation fan 30 continuously circulates the SF6 desorbed from the TSA tower and the remaining nitrogen in the tower to make the SF6 and the remaining nitrogen evenly mixed.

[0056] Step 5: When the detected value of the temperature transmitter reaches the set analysis temperature T3, maintain this temperature value and continue to circulate for 20 min; then turn on the air cooler 20, the second solenoid valve 18, the third solenoid valve 22, and turn on the external recovery device 34 to activate the recovery and separation function. At this time, the SF6 gas that remains in the TSA tower, is analyzed, and is evenly mixed is recovered, separated, and stored by the external recovery device 34 through the precision filter 8, the second connecting pipe 7, the fourth connecting pipe 17, the second solenoid valve 18, the fifth connecting pipe 19, the air cooler 20, the sixth connecting pipe 21, the third solenoid valve 22, and the inlet connecting pipe 4;

[0057] The set value T3 is 80°C;

[0058] A circulation fan 30 is added to the TSA tower body. During the analysis and temperature increase process of the TSA tower, SF6 is gradually analyzed, and the SF6 concentration in the TSA tower gradually increases. Although its diffusion rate increases under high-temperature conditions, diffusion takes time and is time-consuming, reducing work efficiency. In the present invention, an external circulation pipeline is installed on the TSA tower 9, including a fourth solenoid valve 32, a circulation fan 30, a seventh connecting pipe 29, an eighth connecting pipe 31, and a ninth connecting pipe 33; the fourth solenoid valve 32 can prevent gas from directly connecting to the discharge pipe through the circulation bypass and discharging the SF6 mixed gas that has not been effectively adsorbed during the adsorption operation, polluting the environment; the fourth solenoid valve 32 can be opened only after the analysis operation is started to form a circulation path. The circulation fan 30 continuously mixes the analyzed SF6 gas with the nitrogen remaining inside the TSA tower 9 evenly, reducing the time required for mixing only under the action of diffusion after analysis, improving the on-site operation efficiency, and also providing guarantee for the stable-state raw material gas required by the subsequent external recovery device 34.

[0059] Step 6: When the internal pressure value P of the TSA tower 9 is lower than the set value P3, turn off all electrical equipment and end the recovery and separation work of the non-equilibrium concentration SF6 mixed gas inside the electrical equipment.

[0060] The set value P3 is 0.05 MPa.

[0061] Taking the electrical equipment with an initial pressure value of 550 kPa as an example according to the method and equipment provided by the present invention:

[0062] (1) When using a traditional recovery device to recover the pressure in the gas chamber of the electrical equipment from 550 kPa to 50 kPa, the recovery rate can be estimated to be 90.9% at this time according to the pressure, which is quite different from the required recovery rate of more than 96.5%.

[0063] (2) When using the recovery device of the present invention, when initially recovering to 50 kPa, nitrogen is injected into the electrical equipment. The minimum pressure value of the injected nitrogen is 107 kPa, and the minimum pressure value in the electrical equipment after injecting nitrogen needs to reach 157 kPa. Only at this time can the continued recovery of the diluted SF6 gas be satisfied. When the chamber pressure reaches 50 kPa again, the recovery rate is approximately 97.1%. Therefore, when using this method, the final pressure in the electrical equipment after injecting nitrogen should be at least 157 kPa and at most the rated pressure value of the electrical equipment. If calculated by filling nitrogen to the rated pressure value of 550 kPa, the final recovery rate can reach 99.17%. That is, after using the present invention, the SF6 recovery rate range that can be achieved by one-time nitrogen filling and recovery is 97.1 - 99.17%. In addition, nitrogen can be repeatedly filled and recovered to continuously improve the recovery rate. The mixed gas after nitrogen filling is recovered and separated using the present invention.

[0064] (3) The recovery rate estimation method adopted in the present invention is estimated using the ideal gas law. After transforming the ideal gas law formula, we can get: m = PVM / (RT). In the actual application of the present invention, the volume V, molar mass M, ideal gas constant R, and ideal gas thermodynamic temperature T can be regarded as constants. Then the ratio of the gas recovery rate can be simplified to the pressure ratio, that is:

[0065] Recovery rate . Then the final relationship can be transformed into: P 氮 = 2500 / {P 额 (1 - W)}. Where the pressure value P 氮 in the electrical equipment after nitrogen filling is determined by the minimum value of the recovery rate W, which is 97.1%. The maximum value of P 氮 cannot exceed the rated gas pressure P 额 of the electrical equipment.

[0066] (4) When using the complete set of equipment of the present invention, because it adopts the direct recovery function after nitrogen injection dilution and recovery to perform TSA adsorption enrichment, desorption, and cyclic mixing uniformity on the diluted dynamic concentration SF6 mixed gas, a fixed concentration of SF6 mixed gas can be achieved. Nitrogen injection dilution treatment can be carried out within the pressure value range provided by the present invention, and it can ensure that the SF6 recovery rate reaches more than 97.1%, and the diluted SF6 concentration does not restrict the SF6 recovery and separation equipment.

[0067] The present invention solves the problem of recovering non-equilibrium concentration SF6 mixed gas, designs a recovery and treatment device for non-equilibrium concentration SF6 mixed gas, connects it to SF6 electrical equipment. During recovery, the diluted non-equilibrium concentration SF6 mixed gas is recovered into the TSA tower by the recovery and treatment device for non-equilibrium concentration SF6 mixed gas for low-temperature adsorption and enrichment. After the gas recovery in the electrical equipment is completed, SF6 is desorbed by heating and mixed with the remaining nitrogen to form a SF6 mixed medium with an equilibrium concentration. The raw gas with dynamic concentration changes during recovery is transformed into a SF6 mixed medium with a fixed and relatively high concentration, which is convenient for the external recovery device to establish stable material balance parameters when using the membrane separation treatment method, avoiding the excessive content of SF6 (500 ppm) in the separated nitrogen due to the concentration fluctuation of the raw gas, and also reducing the storage volume required for directly recovering the mixed gas. During the process of nitrogen injection dilution and SF6 recovery, the SF6 emission amount and gas storage volume are reduced, and the requirement of high recovery rate in SF6 recovery work can be smoothly implemented.

[0068] Compared with the prior art, the beneficial effects of the present invention at least include:

[0069] (1) The present invention makes the recovered nitrogen and SF6 mixed gas quickly and evenly distributed, ensures the effect of nitrogen and SF6 membrane separation, and enables SF6 to be completely separated as much as possible to avoid being discharged into the atmosphere.

[0070] (2) By improving the SF6 separation effect, the present invention fully ensures the SF6 recovery rate and reduces the impact of the high greenhouse gas SF6 on the ecological environment.

[0071] (3) The present invention enables effective separation of SF6 and nitrogen at the substation site, eliminating the need for storing, transporting, and reprocessing the mixed gas, thus saving manpower, material resources, and financial resources.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific implementation manners of the present invention, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for recovering and treating non-equilibrium concentration SF6 mixed gas in electrical equipment, characterized in that: The recovery and processing equipment includes: an electrical equipment connecting pipe (1), an external recovery device (34), an inlet connecting pipe (4), an outlet connecting pipe (5), a TSA tower (9), an exhaust gas discharge pipe (16), an air cooler (20), a PID controller (28) and a circulating fan (30); One end of the electrical equipment connecting pipe (1) is connected to the electrical equipment gas chamber, and the other end is connected to the first connecting pipe (3); one end of the inlet connecting pipe (4) is connected to the inlet of the external recovery device (34), and the other end is connected to the first connecting pipe (3); the outlet of the external recovery device (34) is connected to the outlet connecting pipe (5); the outlet connecting pipe (5) is connected to the TSA tower (9) and is used to transport the SF6 mixed gas in the electrical equipment gas chamber to the TSA tower (9); The TSA tower (9) is connected to a PID controller (28) for recovering the SF6 mixed gas; the TSA tower (9) is connected to a circulating fan (30) for mixing the SF6 mixed gas analyzed in the TSA tower (9); the TSA tower (9) is connected to an exhaust gas discharge pipe (16) for discharging nitrogen remaining after recovering the SF6; The inlet connecting pipe (4) is also connected to the air cooler (20) to cool down the high-temperature SF6 analyzed in the TSA tower, and to transport the analyzed and evenly mixed SF6 to an external recovery device (34) for recovery, separation and storage; The recycling method comprises the following steps: Step 1, connecting the electrical equipment air chamber to the electrical equipment air chamber interface connecting pipe (1), and connecting the external recovery device (34) to the air inlet connecting pipe (4) and the air outlet connecting pipe (5); Step 2, start the refrigeration unit (23) to reduce the internal temperature of the TSA tower, start the external recovery device (34) to directly recover the functional process, when the temperature transmitter (10) reaches the preset temperature value, transmit the temperature value to the PID controller (28), the PID controller (28) adjusts the opening of the first electric proportional control valve (2), controls the flow rate of the recovered gas, and makes the internal working temperature of the TSA tower (9) stable within the set range; Step 3, the gas in the electrical equipment enters the interior of the TSA tower (9) through the first electric proportional control valve (2), and the non-equilibrium concentration SF6 gas is adsorbed and retained in the TSA tower (9). When the pressure transmitter (12) detects that the pressure inside the TSA tower (9) reaches a set value, the pressure value is transmitted to the PID controller (28), and the PID controller (28) adjusts the opening of the second electric proportional control valve (15), and the nitrogen remaining after adsorption in the TSA tower is discharged through the second electric proportional control valve (15); Step 4, after the gas in the electrical equipment is recovered, the refrigeration unit (23) is turned off, the heater (13) in the TSA tower is turned on, the external recovery device (34) is turned off to directly recover the process, the fourth solenoid valve (32) is turned on, and the circulating fan (30) is turned on. The circulating fan (30) continuously circulates the SF6 analyzed in the TSA tower and the residual nitrogen in the tower, so that the SF6 and the residual nitrogen are evenly mixed; Step 5, when the detection value of the temperature transmitter (10) reaches the set desorption temperature, the temperature value is maintained, the cycle is continued, and then the air cooler (20) and the external recovery device (34) are turned on for recovery and separation functions, and the SF6 gas retained and desorbed in the TSA tower and mixed evenly is recovered, separated and stored through the external recovery device; Step 6: When the internal pressure value of the TSA tower (9) is lower than the set value, all electrical equipment is turned off, and the recovery and separation work of the non-equilibrium concentration SF6 mixed gas in the electrical equipment is terminated.

2. The method for recovering and treating non-equilibrium concentration SF6 mixed gas in electrical equipment according to claim 1, characterized in that: A first electric proportional regulating valve (2) is arranged between the electrical equipment connecting pipe (1) and the first connecting pipe (3), and a first solenoid valve (6) and a second connecting pipe (7) are connected between the outlet connecting pipe (5) and the TSA tower (9).

3. The method for recovering and treating non-equilibrium concentration SF6 mixed gas in electrical equipment according to claim 2, characterized in that: A precision filter (8) is provided between the second connecting pipe (7) and the TSA tower (9). The precision filter (8) is installed at the lower inlet of the TSA tower (9). The precision filter (8) can filter solid particles to prevent the gas analyzed from the TSA tower (9) from containing solid particles and damaging components after flowing out.

4. The method for recovering and treating non-equilibrium concentration SF6 mixed gas in electrical equipment according to claim 1, characterized in that: The TSA tower (9) is equipped with a temperature transmitter (10), a TSA tower condenser (11), a pressure transmitter (12) and a TSA tower heater (13); The condenser (11) in the TSA tower is connected to the refrigeration unit (23) to form a cooling cycle; one end of the third connecting pipe (14) is connected to the outlet of the TSA tower (9), and the other end is connected to the second electric proportional regulating valve (15); the exhaust gas discharge pipe (16) is connected to the second electric proportional regulating valve (15); one end of the seventh connecting pipe (29) is connected to the inlet of the circulation fan (30), and the other end is connected to the third connecting pipe (14); one end of the eighth connecting pipe (31) is connected to the circulation fan (30), and the other end is connected to the fourth solenoid valve (32); one end of the ninth connecting pipe (33) is connected to the bottom interface of the TSA tower (9), and the other end is connected to the fourth solenoid valve (32).

5. The method for recovering and treating non-equilibrium concentration SF6 mixed gas in electrical equipment according to claim 2, characterized in that: The second connecting pipe (7) is connected to one end of the fourth connecting pipe (17), and the other end of the fourth connecting pipe (17) is connected to the second solenoid valve (18); one end of the fifth connecting pipe (19) is connected to the second solenoid valve (18), and the other end is connected to the air cooler (20); one end of the sixth connecting pipe (21) is connected to the air cooler (20), and the other end is connected to the third solenoid valve (22), and the third solenoid valve (22) is connected to the inlet connecting pipe (4).

6. The method for recovering and treating non-equilibrium concentration SF6 mixed gas in electrical equipment according to claim 4, characterized in that: The temperature transmitter (10) is connected to the PID controller (28) via a temperature data transmission line (24); the pressure transmitter (12) is connected to the PID controller (28) via a pressure data transmission line (26); the PID controller (28) is connected to the first electric proportional control valve (2) via a first control line (25); and the second electric proportional control valve (15) is connected to the PID controller (28) via a second control line (27).

7. The method for recovering and treating non-equilibrium concentration SF6 mixed gas in electrical equipment according to claim 1, characterized in that: Step 2 specifically includes: starting the refrigeration unit (23) to reduce the internal temperature of the TSA tower via the condenser (11) in the TSA tower, starting the external recovery device (34) to directly recover the functional process, opening the first solenoid valve (6), and when the temperature transmitter (10) reaches a preset temperature value, transmitting the temperature value to the PID controller (28) through the temperature data transmission line (24), and the PID controller (28) adjusts the opening of the first electric proportional control valve (2) according to the preset range of the temperature value and through the first control line (25), controls the flow rate of the recovered gas, and stabilizes the internal working temperature of the TSA tower (9) within the set range.

8. The method for recovering and treating non-equilibrium concentration SF6 mixed gas in electrical equipment according to claim 1, characterized in that: Step 3 specifically includes: the gas in the electrical equipment enters the interior of the TSA tower (9) through the electrical equipment connecting pipe (1), the first electric proportional control valve (2), the first connecting pipe (3), the inlet connecting pipe (4), the external recovery device (34), the outlet connecting pipe (5), the first solenoid valve (6), the second connecting pipe (7), and the precision filter (8); the non-equilibrium concentration SF6 gas is adsorbed and retained by the SF6 adsorbent loaded in the TSA tower under low temperature conditions; when the pressure transmitter (12) detects that the internal pressure of the TSA tower (9) reaches a set value, the pressure value is transmitted to the PID controller (28) through the pressure data transmission line (26); the PID controller (28) adjusts the opening of the second electric proportional control valve (15) according to the preset range of the pressure value and through the second control line (27), and discharges the nitrogen remaining in the TSA tower after adsorption through the second electric proportional control valve (15).

9. The method for recovering and treating non-equilibrium concentration SF6 mixed gas in electrical equipment according to claim 1, characterized in that: Step 4 specifically includes: after the gas in the electrical equipment is recovered, the refrigeration unit (23) is turned off, the heater (13) in the TSA tower is turned on, the first solenoid valve (6) is turned off, the second electric proportional control valve (15) is turned off and locked, the gas is prohibited from being discharged, the external recovery device (34) is turned off to directly recover the process, the fourth solenoid valve (32) is turned on, and the circulating fan (30) is turned on, and the circulating fan (30) continuously circulates the SF6 analyzed in the TSA tower and the residual nitrogen in the tower, so that the SF6 and the residual nitrogen are evenly mixed.

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