Equipment and method for recycling and processing non-equilibrium concentration SF6 mixed gas in electrical equipment

Abstract

The invention discloses non-equilibrium concentration SF6 mixed gas recovery processing equipment and method in electrical equipment, and belongs to the technical field of SF6 gas recovery, the recovery processing equipment comprises an electrical equipment connecting pipe, an external recovery device, an inlet connecting pipe, an outlet connecting pipe, a TSA tower, a tail gas discharge pipe, an air cooler, a PID controller and a circulating fan; the electrical equipment connecting pipe is connected with the electrical equipment air chamber and the first connecting pipe, the inlet connecting pipe is connected with an inlet of the external recovery device and the first connecting pipe, an outlet of the external recovery device is connected with the outlet connecting pipe, and the outlet connecting pipe is connected with the TSA tower; the TSA tower is connected with a tail gas discharge pipe; the inlet connecting pipe is also connected with an air cooler, and the analyzed and uniformly mixed SF6 is conveyed to an external recycling device to be recycled, separated and stored. According to the invention, the recovered mixed gas of nitrogen and SF6 is rapid and uniform, the membrane separation effect of nitrogen and SF6 is ensured, SF6 is prevented from being discharged into the atmosphere, and the recovery rate of SF6 is fully ensured.

Description

Technical Field

[0001] The present application belongs to the technical field of SF6 gas recovery, and in particular, relates to a device and method for recovering and processing non-equilibrium concentration SF6 mixed gas in electrical equipment. Background Art

[0002] At present, with the rapid development of social economy, power transmission and transformation stations are continuously built and put into operation, and the number of power transmission and transformation equipment continues to increase. SF6 (sulfur hexafluoride) is used in large quantities in power transmission and transformation equipment as an excellent insulating arc extinguishing medium. SF6 has a very strong greenhouse effect, which is more than 23,000 times that of carbon dioxide. SF6 must be recycled during the maintenance and decommissioning of power transmission and transformation equipment to avoid the emission of high greenhouse effect gas SF6 into the atmosphere. At present, when the absolute pressure of SF6 in power transmission and transformation equipment is recovered to below a certain pressure (generally 50kPa), the existing recovery device cannot completely recycle SF6 due to technical limitations, and there is more than 3% residue. The residual SF6 will be discharged into the air and pollute 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 power transmission and transformation equipment, dilute SF6 and then recycle it. However, the concentration of the diluted SF6 gas is low, and the nitrogen filled in a short period of time cannot be evenly mixed with SF6 only by diffusion. In particular, it takes a long time to mix evenly in large air chambers such as circuit breakers and busbars. The existing SF6 recovery device is used to directly recover the SF6 nitrogen mixture, but it is impossible to separate SF6 from nitrogen because the mixture cannot be liquefied due to the presence of nitrogen. On-site storage requires large-volume storage tanks or more cylinders. The frequent replacement and transportation of storage tanks and cylinders also adds a large 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 SF6 concentration in the gas chamber of electrical equipment and the dynamic changes in SF6 concentration during the recovery process, the membrane separation device cannot establish a dynamic equilibrium relationship between concentration, pressure, flow and temperature for SF6 gases of different concentrations during operation. As a result, during the recovery and separation process, the SF6 content on the SF6 permeate side is still high, and the exhaust gas cannot meet the exhaust requirements. A certain amount of SF6 will still be discharged into the air, causing environmental pollution.

[0005] Therefore, there is an urgent need for a non-equilibrium concentration SF6 mixed gas recovery and processing equipment and method to achieve the recovery and effective separation of the non-equilibrium concentration SF6 nitrogen mixed gas and solve the problems in the nitrogen injection recovery process. Summary of the invention

[0006] In order to solve the problem of recovering the dynamic concentration SF6 mixed gas during the nitrogen injection recovery process, the present invention provides a non-equilibrium concentration SF6 gas recovery and processing device and method in electrical equipment. The method can convert the non-equilibrium low concentration SF6 gas to an equilibrium state, and can control its concentration to about 30% of the suitable processing range of the SF6 / N2 membrane separation device on the market, meeting the use conditions of the on-site mixed gas processing equipment.

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

[0008] The first aspect of the present invention discloses a non-equilibrium concentration SF6 mixed gas recovery and treatment device in an electrical device, comprising: an electrical device connecting pipe, an external recovery device, an inlet connecting pipe, an outlet connecting pipe, a TSA (Temperature Swing Adsorption) tower, an exhaust pipe, an air cooler, a PID controller (Proportion Integration Differentiation) and a circulating fan; One end of the electrical equipment connecting pipe is connected to the electrical equipment gas chamber, 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 recovery device, and the other end is connected to 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, so as to transport the SF6 mixed gas in the electrical equipment gas chamber to the TSA tower. The TSA tower is connected to a PID controller for recycling the SF6 mixed gas; the TSA tower is connected to a circulating fan for mixing the SF6 mixed gas analyzed in the TSA tower; the TSA tower is connected to an exhaust gas discharge pipe for discharging the remaining nitrogen after SF6 is recovered; The inlet connecting pipe is also connected to an air cooler 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 for recovery, separation and storage.

[0009] Preferably, a first electric proportional regulating valve is provided 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.

[0010] Preferably, a precision filter is provided 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.

[0011] Preferably, the TSA tower is equipped with a temperature transmitter, a TSA tower condenser, a pressure transmitter and a TSA tower heater; The condenser in the TSA tower is connected to the refrigeration unit to form a cooling cycle; one end of the third connecting pipe is connected to the TSA tower outlet, and the other end is connected to the second electric proportional regulating valve, and the exhaust gas exhaust pipe is connected to the second electric proportional regulating valve; one end of the seventh connecting pipe is connected to the circulating fan inlet, and the other end is connected to the third connecting pipe; one end of the eighth connecting pipe is connected to the circulating fan, and the other end is connected to the fourth solenoid valve; one end of the ninth connecting pipe is connected to the bottom interface of the TSA tower, and the other end is connected to the fourth solenoid valve.

[0012] Preferably, 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 the second solenoid valve; one end of the fifth connecting pipe is connected to the second solenoid valve, and the other end is connected to the air cooler; one end of the sixth connecting pipe is connected to the air cooler, and the other end is connected to the third solenoid valve, and the third solenoid valve is connected to the inlet connecting pipe.

[0013] Preferably, the temperature transmitter is connected to the PID controller via a temperature data transmission line; the pressure transmitter is connected to the PID controller via a pressure data transmission line; the PID controller is connected to the first electric proportional control valve via a first control line; and the second electric proportional control valve is connected to the PID controller via a second control line.

[0014] The second aspect of the present invention discloses a method for recovering and treating a non-equilibrium concentration SF6 mixed gas in an electrical device, based on the device for recovering and treating a non-equilibrium concentration SF6 mixed gas in an electrical device, comprising the following steps: Step 1, connecting the electrical equipment air chamber to the electrical equipment air chamber interface connecting pipe, and connecting the external recovery device to the air inlet connecting pipe and the air outlet connecting pipe; Step 2, start the refrigeration unit to reduce 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 control valve to control the recovery gas flow rate, so that the internal working temperature of the TSA tower is stable within the set range; Step 3: The gas in the electrical equipment enters the TSA tower through the first electric proportional control valve, and the non-equilibrium concentration SF6 gas is adsorbed and retained in the TSA tower. When the pressure transmitter detects that the pressure inside the TSA tower reaches the set value, the pressure value is transmitted to the PID controller. The PID controller adjusts the opening of the second electric proportional control valve to discharge the residual nitrogen after adsorption in the TSA tower through the second electric proportional control valve. Step 4: 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 direct recovery process of the external recovery device, turn on the fourth solenoid valve, turn on the circulating fan, and the circulating fan continuously circulates the SF6 analyzed in the TSA tower and the residual nitrogen in the tower to evenly mix the SF6 and the residual nitrogen; Step 5, when the temperature transmitter detection value reaches the set desorption temperature, the temperature value is maintained, the cycle continues, and then the air cooler and the external recovery device recovery and separation function are turned on to recover, separate and store the SF6 gas retained and desorbed in the TSA tower through the external recovery device; Step 6: When the internal pressure value of the TSA tower is lower than the set value, all electrical equipment is turned off to end the recovery and separation work of the non-equilibrium concentration SF6 mixed gas in the electrical equipment.

[0015] Preferably, step 2 specifically includes: starting the refrigeration unit to lower 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, opening the first solenoid valve, and when the temperature transmitter reaches the preset temperature value, transmitting the temperature value to the PID controller through the temperature data transmission line. The PID controller adjusts the opening of the first electric proportional control 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 stable within the set range.

[0016] Preferably, step 3 specifically includes: the gas in the electrical equipment enters the TSA tower through the electrical equipment connecting pipe, the first electric proportional control 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; 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 monitors that the internal pressure of the TSA tower reaches the set value, the pressure value is transmitted to the PID controller through the pressure data transmission line; the PID controller adjusts the opening of the second electric proportional control valve according to the preset range of the pressure value and through the second control line, and discharges the residual nitrogen after adsorption in the TSA tower through the second electric proportional control valve.

[0017] Preferably, step 4 specifically includes: after the gas in the electrical equipment is recovered, the refrigeration unit is turned off, the heater in the TSA tower is turned on, the first solenoid valve is turned off, the second electric proportional control valve is turned off and locked, gas discharge is prohibited, the external recovery device is turned off for direct recovery, the fourth solenoid valve is turned on, and the circulating fan is turned on. The circulating fan continuously circulates the SF6 analyzed in the TSA tower and the residual nitrogen in the tower to evenly mix the SF6 and the residual nitrogen.

[0018] The present invention solves the problem of recycling non-equilibrium concentration SF6 mixed gas, designs non-equilibrium concentration SF6 mixed gas recycling and processing equipment, connects it to SF6 electrical equipment, and during recycling, the diluted non-equilibrium concentration SF6 mixed gas is recycled to the TSA tower for low-temperature adsorption enrichment through the non-equilibrium concentration SF6 mixed gas recycling and processing equipment. After the gas recovery in the electrical equipment is completed, SF6 is analyzed by heating and mixed with residual nitrogen to form a SF6 mixed medium with an equilibrium concentration, and the recycled raw gas with dynamic concentration changes is converted into a fixed high-concentration SF6 mixed medium, which is convenient for establishing stable material balance parameters when the external recovery device adopts a membrane separation treatment method, avoiding the SF6 content in the separated nitrogen exceeding the standard (500ppm) due to the fluctuation of the raw gas concentration, and also reducing the storage volume required for directly recovering the mixed gas. In the process of nitrogen injection dilution SF6 recovery, the SF6 emission and gas storage volume are reduced, and the requirement for high recovery rate in SF6 recovery work can be smoothly implemented.

[0019] Compared with the prior art, the beneficial effects of the present invention include at least: (1) The present invention allows the recovered nitrogen and SF6 mixed gas to be quickly and uniformly mixed, thereby ensuring the membrane separation effect of nitrogen and SF6, and separating SF6 as completely as possible to avoid discharge into the atmosphere.

[0020] (2) The present invention improves the SF6 separation effect, fully guarantees the SF6 recovery rate, and reduces the impact of high greenhouse gas SF6 on the ecological environment.

[0021] (3) The present invention enables SF6 nitrogen to be effectively separated at the substation site, eliminating the need to store, transport and reprocess the mixed gas, thus saving manpower, material and financial resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a non-equilibrium concentration SF6 mixed gas recovery and processing equipment in electrical equipment; In the figure: 1. Electrical equipment connecting pipe; 2. First electric proportional control 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. Condenser in TSA tower; 12. Pressure transmitter; 13. Heater in TSA tower; 14. Third connecting pipe; 15. Second electric proportional control valve; 16. Exhaust 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 DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0024] Embodiment 1 of the present invention provides a non-equilibrium concentration SF6 mixed gas recovery and processing device in electrical equipment, including: an electrical equipment connecting pipe 1, a first electric proportional control valve 2, a first connecting pipe 3, an inlet connecting pipe 4, an outlet connecting pipe 5, a first solenoid valve 6, a second connecting pipe 7, a precision filter 8, a TSA tower 9, a temperature transmitter 10, a condenser in the TSA tower 11, a pressure transmitter 12, a heater in the TSA tower 13, a third connecting pipe 14, a second electric proportional control valve 15, an exhaust gas exhaust pipe 16, a fourth connecting pipe 17, a second solenoid valve 18, a fifth connecting pipe 19, an air cooler 20, a sixth connecting pipe 21, a third solenoid valve 22, a refrigeration unit 23, a temperature data transmission line 24, a first control line 25, a pressure data transmission line 26, a second control line 27, a PID controller 28, a seventh connecting pipe 29, a circulating fan 30, an eighth connecting pipe 31, a fourth solenoid valve 32, a ninth connecting pipe 33, and an external recovery device 34.

[0025] 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.

[0026] One end of the electrical equipment connecting pipe 1 is connected to the electrical equipment air chamber interface, and the other end is connected to the first electric proportional control valve 2; one end of the first connecting pipe 3 is connected to the first electric proportional control valve 2, and the other end is connected to the inlet connecting pipe 4, and is 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 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 end inlet of the TSA tower 9.

[0027] The precision filter 8 can filter solid particles to prevent the gas analyzed from the TSA tower 9 from containing solid particles such as dust, which may damage components after flowing out.

[0028] The TSA tower 9 is installed with a temperature transmitter 10, a TSA tower condenser 11, a pressure transmitter 12 and a TSA tower heater 13; the TSA tower 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 electric proportional regulating valve 15, and the exhaust gas exhaust 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 circulating 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 circulating 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.

[0029] 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.

[0030] Embodiment 2 of the present invention provides a method for processing and recovering non-equilibrium concentration SF6 mixed gas in electrical equipment, comprising the following steps: Step 1, connect the electrical equipment air chamber to the electrical equipment connecting pipe 1, and connect 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 9, 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 recovery gas flow, and ensures that the internal working temperature of the TSA tower 9 is stable within the set range; Step 2 specifically includes starting the refrigeration unit 23 to reduce the internal temperature of the TSA tower 9 through 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 the preset temperature value T0, transmitting the temperature value T 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 (T1~T2) of the temperature value T and through the first control line 25, controls the recovery gas flow, and ensures that the internal working temperature of the TSA tower 9 is stable within the set range (T1~T2); 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; The preset temperature value T0 is -10℃; The adsorption working temperature condition of TSA tower 9 is set, and the temperature value monitored in real time by temperature transmitter 10 is transmitted to PID controller 28. PID controller 28 transmits the control feedback signal to the opening of the first electric proportional control valve 2 according to the set temperature value to control the recovery flow rate. The high temperature limit setting value T2 can avoid the excessive recovery flow rate and increased heat exchange, which makes the internal temperature of TSA tower 9 too high and the adsorption efficiency low; the low temperature limit setting value T1 can avoid the system from continuously reducing the flow rate to meet the low temperature condition, reducing the recovery rate and affecting the on-site work efficiency.

[0031] Step 3: The gas in the electrical equipment enters 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 the set value, the pressure value P is transmitted to the PID controller 28. 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 3 specifically includes: the gas in the electrical equipment enters the TSA tower 9 through the electrical equipment connecting pipe 1, the first electric proportional control 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; 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 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 control valve 15 according to the preset range (P1~P2) of the pressure value P and through the second control line 27, and discharges a large amount of nitrogen remaining after adsorption in the TSA tower through the second electric proportional control valve 15; In a preferred but non-limiting embodiment of the present invention, the preset range (P1-P2) of the pressure value P is 1MPa-1.5MPa; The set value P0 is 1.25MPa; The adsorption working pressure control condition of TSA tower 9 is set to avoid pressure changes caused by temperature fluctuations inside low-temperature TSA tower 9. Because high pressure can increase the adsorption amount when TSA tower 9 is working, and pressure reduction will reduce the adsorption amount. The process of changing from high pressure to low pressure will produce a desorption phenomenon, causing the SF6 content of the gas discharged into the air to exceed the standard. Therefore, in the present invention, the internal working pressure of 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 transmitted to the second electric proportional control valve 15 by the PLD controller. The exhaust gas flow rate is controlled by controlling the second electric proportional control valve 15, so that the pressure inside the TSA tower can be controlled to be stable.

[0032] 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 4 specifically includes, after the gas in the electrical equipment is recovered, closing the refrigeration unit 23, opening the heater 13 in the TSA tower, closing the first solenoid valve 6, closing the second electric proportional control valve 15 and locking it, prohibiting gas discharge, closing the external recovery device 34 to directly recover the process, opening the fourth solenoid valve 32, and opening the circulating fan 30. The circulating fan 30 continuously circulates the SF6 analyzed in the TSA tower and the residual nitrogen in the tower to evenly mix the SF6 and the residual nitrogen.

[0033] Step 5, when the temperature transmitter detection value reaches the set analysis temperature T3, maintain the temperature value and continue to circulate for 20 minutes; then open the air cooler 20, open the second solenoid valve 18, open the third solenoid valve 22, and open the external recovery device 34 recovery and separation function. At this time, the SF6 gas retained and analyzed and mixed evenly in the TSA tower 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; The set value T3 is 80°C; A circulating fan 30 is added to the TSA tower body. During the decomposition and heating process of the TSA tower, SF6 is gradually decomposed, and the SF6 concentration in the TSA tower gradually increases. Although its diffusion rate increases under high temperature conditions, the diffusion takes time, which is relatively time-consuming and reduces work efficiency. In the present invention, the TSA tower 9 is installed with an external circulation pipeline, including a fourth solenoid valve 32, a circulating 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 the gas from being directly connected to the exhaust pipe through the circulation bypass to discharge the SF6 mixed gas that has not been effectively adsorbed during the adsorption work, thereby polluting the environment; the fourth solenoid valve 32 can be opened only after the decomposition work is started to form a circulation passage, and the circulating fan 30 continuously mixes the decomposed SF6 gas with the residual nitrogen in the TSA tower 9, thereby reducing the time required for mixing only under diffusion after decomposition, improving on-site operation efficiency, and also providing a guarantee for the stable raw material gas required for the subsequent external recovery device 34.

[0034] Step 6: When the internal pressure value P of the TSA tower 9 is lower than the set value P3, all electrical equipment is turned off to end the recovery and separation work of the non-equilibrium concentration SF6 mixed gas in the electrical equipment.

[0035] The set value P3 is 0.05 MPa.

[0036] According to the method and equipment provided by the present invention, an electrical device with an initial pressure value of 550 kPa is used as an example to illustrate: (1) When the pressure in the gas chamber of electrical equipment is recovered from 550 kPa to 50 kPa using a traditional recovery device, the recovery rate can be estimated to be 90.9% based on the pressure, which is significantly different from the required recovery rate of more than 96.5%.

[0037] (2) When the recovery device of the present invention is used, nitrogen is injected into the electrical equipment when the initial recovery reaches 50 kPa. The minimum pressure value of the nitrogen injection is 107 kPa. The minimum pressure value after the nitrogen is injected into the electrical equipment must reach 157 kPa. Only then can the diluted SF6 gas be recovered. When the pressure of the gas chamber reaches 50 kPa again, the recovery rate is about 97.1%. Therefore, the final pressure after the nitrogen is injected into the electrical equipment using this method should be at least 157 kPa, and the maximum is the rated pressure value of the electrical equipment. If the nitrogen is filled 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 that can be achieved by one nitrogen filling recovery ranges from 97.1% to 99.17%. In addition, the nitrogen filling recovery can be repeated to further improve the recovery rate. The mixed gas after nitrogen filling is recovered and separated using the present invention.

[0038] (3) The recovery rate estimation method used in the present invention adopts the ideal gas law for estimation. After the ideal gas law formula is transformed, it can be obtained: m=PVM / (RT). In the practical application of the present invention, the volume V, molar mass M, ideal gas constant R, and ideal gas thermodynamic temperature T can be used as quantitative factors, and the ratio of gas recovery rate can be simplified to pressure ratio, that is: Recovery rate The final relationship can be transformed into: 氮 =2500 / {P 额 (1-W)}. The pressure value inside the electrical equipment after nitrogen filling is P 氮 The minimum value is determined by the recovery rate W minimum value of 97.1%, P 氮 The maximum value shall not exceed the rated gas pressure P of the electrical equipment. 额 .

[0039] (4) The complete set of equipment of the present invention can achieve a fixed concentration of SF6 mixed gas by using the direct recovery function after nitrogen injection, dilution and recovery, and performing TSA adsorption enrichment, analysis and circulation mixing on the diluted dynamic concentration SF6 mixed gas. Nitrogen filling and dilution treatment can be performed within the pressure range provided by the present invention, and the SF6 recovery rate can be ensured to be above 97.1%. Moreover, the concentration of SF6 after dilution does not restrict the SF6 recovery and separation equipment.

[0040] The present invention solves the problem of recycling non-equilibrium concentration SF6 mixed gas, designs non-equilibrium concentration SF6 mixed gas recycling and processing equipment, connects it to SF6 electrical equipment, and during recycling, the diluted non-equilibrium concentration SF6 mixed gas is recycled to the TSA tower for low-temperature adsorption enrichment through the non-equilibrium concentration SF6 mixed gas recycling and processing equipment. After the gas recovery in the electrical equipment is completed, SF6 is analyzed by heating and mixed with residual nitrogen to form a SF6 mixed medium with an equilibrium concentration, and the recycled raw gas with dynamic concentration changes is converted into a fixed high-concentration SF6 mixed medium, which is convenient for establishing stable material balance parameters when the external recovery device adopts a membrane separation treatment method, avoiding the SF6 content in the separated nitrogen exceeding the standard (500ppm) due to the fluctuation of the raw gas concentration, and also reducing the storage volume required for directly recovering the mixed gas. In the process of nitrogen injection dilution SF6 recovery, the SF6 emission and gas storage volume are reduced, and the requirement for high recovery rate in SF6 recovery work can be smoothly implemented.

[0041] Compared with the prior art, the beneficial effects of the present invention include at least: (1) The present invention allows the recovered nitrogen and SF6 mixed gas to be quickly and uniformly mixed, thereby ensuring the membrane separation effect of nitrogen and SF6, and separating SF6 as completely as possible to avoid discharge into the atmosphere.

[0042] (2) The present invention improves the SF6 separation effect, fully guarantees the SF6 recovery rate, and reduces the impact of high greenhouse gas SF6 on the ecological environment.

[0043] (3) The present invention enables SF6 nitrogen to be effectively separated at the substation site, eliminating the need to store, transport and reprocess the mixed gas, thus saving manpower, material and financial resources.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A non-equilibrium concentration SF6 mixed gas recovery and treatment device in electrical equipment, characterized by: include: 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.

2. The non-equilibrium concentration SF6 mixed gas recovery and processing equipment 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 non-equilibrium concentration SF6 mixed gas recovery and processing equipment 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 non-equilibrium concentration SF6 mixed gas recovery and processing equipment 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 non-equilibrium concentration SF6 mixed gas recovery and processing equipment 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 non-equilibrium concentration SF6 mixed gas recovery and treatment equipment 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. A method for recovering and treating a non-equilibrium concentration SF6 mixed gas in an electrical device, based on a non-equilibrium concentration SF6 mixed gas recovery and treatment device in an electrical device according to any one of claims 1 to 6, characterized in that: The following steps are involved: 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.

8. The method for recovering and treating non-equilibrium concentration SF6 mixed gas in electrical equipment according to claim 7, 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.

9. The method for recovering and treating non-equilibrium concentration SF6 mixed gas in electrical equipment according to claim 7, 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).

10. The method for recovering and treating non-equilibrium concentration SF6 mixed gas in electrical equipment according to claim 7, 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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