Sulfur hexafluoride collection and purification in waste gas, zero emission equipment and working method thereof

Abstract

The equipment for collecting and purifying sulfur hexafluoride in waste gas and achieving zero emission includes an air intake recovery pipeline, a gas-liquid separation device, a liquid delivery pipeline, a gas adsorption emission pipeline and a regeneration pipeline; the air outlet of the gas intake recovery pipeline is connected to the air intake at the top of the gas-liquid separation device, the liquid outlet at the bottom of the gas-liquid separation device is connected to the liquid inlet of the liquid delivery pipeline, the air intake of the gas adsorption emission pipeline is connected to the exhaust port at the top of the gas-liquid separation device, the air intake of the regeneration pipeline is connected to the gas adsorption emission pipeline, and the air outlet of the regeneration pipeline is connected to the air intake of the intake recovery pipeline. The present invention realizes the collection, purification and zero emission treatment of sulfur hexafluoride in waste gas through a four-stage treatment process of precision filtration, gas-liquid separation, pressure swing adsorption and atmospheric pressure adsorption. The purity of the collected sulfur hexafluoride can reach more than 99.9%. After further treatment, the sulfur hexafluoride gas can be reused and the saturated adsorption tower can be regenerated.

Description

Technical Field

[0001] The invention belongs to the technical field of sulfur hexafluoride gas recovery, and specifically relates to a zero-emission device for collecting and purifying sulfur hexafluoride in waste gas and a working method thereof. Background Art

[0002] Sulfur hexafluoride is an excellent insulating and arc-extinguishing medium and has been widely used in the power industry. Sulfur hexafluoride gas is a strong greenhouse gas with a global warming potential of about 23,900 times that of carbon dioxide, and has a cumulative effect on global warming.

[0003] In order to reduce the emission of sulfur hexafluoride greenhouse gas from the power industry, the two major domestic power grid companies and related enterprises have carried out sulfur hexafluoride gas recovery and recycling work, and realized the recovery, refilling and purification of sulfur hexafluoride gas; however, sulfur hexafluoride gas leaked in a closed environment, exhaust gas after sulfur hexafluoride detection, and exhaust gas emitted after sulfur hexafluoride purification are blind spots in sulfur hexafluoride management.

[0004] Therefore, the market is in urgent need of sulfur hexafluoride collection and purification in waste gas, zero-emission equipment and its working method, so that it can collect and purify sulfur hexafluoride in waste gas under different concentration conditions, avoid emissions, and reduce environmental pollution. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a device for collecting and purifying sulfur hexafluoride in waste gas and achieving zero emission and a working method thereof, which comprehensively adopts technical processes such as distillation and adsorption to achieve the collection and purification of sulfur hexafluoride in waste gas and zero emission, thereby reducing the generation of environmental pollution.

[0006] In order to solve the above technical problems, the present invention adopts the following technical scheme: a zero-emission equipment for collecting and purifying sulfur hexafluoride in waste gas, including an air intake recovery pipeline, a gas-liquid separation device, a liquid delivery pipeline, a gas adsorption emission pipeline and a regeneration pipeline; the air outlet of the gas intake recovery pipeline is connected to the air inlet at the top of the gas-liquid separation device, the liquid outlet at the bottom of the gas-liquid separation device is connected to the liquid inlet of the liquid delivery pipeline, the air inlet of the gas adsorption emission pipeline is connected to the exhaust port at the top of the gas-liquid separation device, the air inlet of the regeneration pipeline is connected to the gas adsorption emission pipeline, and the air outlet of the regeneration pipeline is connected to the air inlet of the air intake recovery pipeline.

[0007] An intake joint, an intake pressure gauge, a precision filter, a first recovery solenoid valve, a compressor, a first one-way valve, a first pressure-controlled switch, and a second recovery solenoid valve are sequentially arranged along the air flow direction of the intake recovery pipeline.

[0008] The air inlet and the air outlet of the first recovery solenoid valve are connected with a negative pressure recovery pipe, and the negative pressure recovery solenoid valve, the vacuum compressor and the second one-way valve are arranged in sequence on the negative pressure recovery pipe along the air flow direction.

[0009] The gas-liquid separation device comprises a refrigerator, a first gas-liquid separation tower and a second gas-liquid separation tower located below the first gas-liquid separation tower, a gas-liquid separation solenoid valve is arranged between the bottom of the first gas-liquid separation tower and the top of the second gas-liquid separation tower; the gas outlet of the intake air recovery pipeline and the gas inlet of the gas adsorption discharge pipeline are both connected to the top of the first gas-liquid separation tower; the liquid inlet of the liquid delivery pipeline is connected to the bottom of the second gas-liquid separation tower;

[0010] The lower part of the first gas-liquid separation tower is connected to a first instrument pipe, on which a first instrument valve and a separation tower pressure gauge are arranged; a liquid level pipe is arranged between the top and the bottom of the second gas-liquid separation tower, on which a liquid level gauge is arranged;

[0011] The refrigerator is connected to the cooling port of the first gas-liquid separation tower through a first refrigeration connecting pipe and a first refrigeration reflux pipe, and a first refrigeration solenoid valve is provided on the first refrigeration connecting pipe; the refrigerator is connected to the cooling port of the second gas-liquid separation tower through a second refrigeration connecting pipe and a second refrigeration reflux pipe, and a second refrigeration solenoid valve is provided on the second refrigeration connecting pipe.

[0012] An infusion solenoid valve, a booster, a third one-way valve, a second pressure-controlled switch and a liquid sulfur hexafluoride filling interface are arranged in sequence along the liquid flow direction of the liquid delivery pipeline.

[0013] A pressure regulating valve, a first exhaust solenoid valve, a first adsorption tower, a flow regulating needle valve, a second exhaust solenoid valve, a second adsorption tower, a sulfur hexafluoride leakage monitoring sensor, a third adsorption tower and an environmental gas discharge port are sequentially arranged along the gas flow direction of the gas adsorption emission pipeline. A heating rod is arranged in the first adsorption tower, and an adsorption tower pressure gauge is connected to the outside of the first adsorption tower.

[0014] The air inlet of the regeneration pipeline is connected to the gas adsorption exhaust pipeline between the flow regulating needle valve and the second exhaust solenoid valve, and the air outlet of the regeneration pipeline is connected to the air inlet of the precision filter of the gas intake recovery pipeline; the regeneration circuit solenoid valve and the air cooler are arranged in sequence along the air flow direction on the regeneration pipeline.

[0015] A working method of a zero-emission device for collecting and purifying sulfur hexafluoride in waste gas comprises the following steps:

[0016] (1) First, the gas-liquid separation solenoid valve is opened, and the first gas-liquid separation tower and the second gas-liquid separation tower are connected; the refrigerator is started, and the first refrigeration solenoid valve and the second refrigeration solenoid valve are opened to refrigerate the first gas-liquid separation tower and the second gas-liquid separation tower, thereby reducing the temperature in the first gas-liquid separation tower and the second gas-liquid separation tower;

[0017] (2) The air intake connector is connected to the electrical equipment. The raw waste gas in the electrical equipment enters the air intake recovery pipeline, firstly passes through the precision filter to filter out moisture, decomposition products, dust and other impurities, passes through the first recovery solenoid valve, is pressurized by the compressor, and then enters the top of the first gas-liquid separation tower through the first check valve and the second recovery solenoid valve. Gas-liquid separation is performed in the first gas-liquid separation tower. When the pressure of the air intake pressure gauge is lower than 0MPaG, the first recovery solenoid valve is closed, and the first negative pressure recovery solenoid valve and the vacuum compressor are opened. The vacuum compressor is started to perform negative pressure recovery on the waste gas in the electrical equipment to reduce the residual raw waste gas.

[0018] (3) The pressure gauge of the separation tower shall not be set higher than 3.5MPaG. When the gas pressure after the compressor is increased is higher than 3.5MPaG, the first pressure-controlled switch sends a signal to cut off the raw material waste gas recovery process, that is, shut down the compressor and the second recovery solenoid valve;

[0019] (4) The liquid level gauge is a flap-type liquid level gauge, which can be set to high, medium and low limit alarms. When the sulfur hexafluoride liquid level in the second gas-liquid separation tower is at the medium limit alarm, the waste gas recovery process is shut down, that is, the compressor and the second recovery solenoid valve are shut down; when the sulfur hexafluoride liquid level is at the high limit alarm, the refrigerator and the gas-liquid separation solenoid valve are shut down; then the liquid sulfur hexafluoride filling process is started: the liquid sulfur hexafluoride filling port is connected to the cylinder or container, the infusion solenoid valve is opened, the booster is started, and the liquid sulfur hexafluoride in the second gas-liquid separation tower is directly filled into the external cylinder or container through the liquid delivery pipeline; when the second pressure-controlled switch reaches the 3.5MPaG alarm signal, the infusion solenoid valve and the booster are automatically managed to stop the liquid sulfur hexafluoride filling process, and the cylinder or container is replaced and the pressure is released before continuing the filling process;

[0020] (5) After gas-liquid separation, the waste gas is isolated by the gas-liquid separation solenoid valve to the first gas-liquid separation tower. The pressure regulating valve is adjusted to make the gas output pressure in the first gas-liquid separation tower 0.3-0.4MPaG; the first exhaust solenoid valve is opened, and the waste gas is adsorbed by the first adsorption tower. The adsorption pressure is 0.3-0.4MPaG. The opening of the flow regulating needle valve is adjusted to control the waste gas flow rate to 60L / min. After the waste gas is adsorbed by the first adsorption tower, the sulfur hexafluoride content in the waste gas is less than 200ppm (g / g); then the waste gas enters the second adsorption tower through the second exhaust solenoid valve. The adsorption pressure in the second adsorption tower is normal pressure. After the waste gas is treated by the second adsorption tower, the sulfur hexafluoride content in the waste gas is 0;

[0021] (6) The sulfur hexafluoride leakage alarm sensor monitors whether the exhaust gas contains sulfur hexafluoride. If so, it will alarm and prompt the replacement or offline treatment of the second adsorption tower; the third adsorption tower is the last measure to ensure zero emission of sulfur hexafluoride in the exhaust gas and a backup adsorption tower. When the second adsorption tower is replaced or offline after adsorption saturation, the third adsorption tower is temporarily used to ensure that the sulfur hexafluoride content in the exhaust gas discharged from the environmental protection gas discharge port is 0.

[0022] In step (5), after the first adsorption tower is saturated with adsorption, regeneration is performed through the regeneration pipeline; the regeneration process is as follows: the first exhaust solenoid valve and the second exhaust solenoid valve are closed, and the heating rod is started to heat the adsorbent in the first adsorption tower, and the heating temperature is 150°C-200°C; then the air cooler, the regeneration circuit solenoid valve, the first recovery solenoid valve and the second recovery solenoid valve are turned on, and the compressor is started at the same time, and the regenerated gas in the first adsorption tower enters the first gas-liquid separation tower through the regeneration pipeline and the air intake recovery pipeline, and the refrigerator is turned on for auxiliary refrigeration during the recovery of the regenerated gas; when the pressure gauge pressure of the adsorption tower is lower than 0MPaG, the first recovery solenoid valve is closed, and the negative pressure recovery solenoid valve and the vacuum compressor are turned on to regenerate the first adsorption tower by vacuum heating.

[0023] By adopting the above technical scheme, the present invention realizes the collection, purification and zero-emission treatment of sulfur hexafluoride in waste gas through a four-stage treatment process of precision filtration, gas-liquid separation, pressure swing adsorption and atmospheric pressure adsorption. The purity of the collected sulfur hexafluoride can reach more than 99.9%. After further treatment, the sulfur hexafluoride gas can be reused, and the saturated adsorption tower can also be recycled. The present invention solves the problem of treating sulfur hexafluoride waste gas with a wide range of different concentrations, improves the reuse rate of sulfur hexafluoride gas, reduces sulfur hexafluoride gas emissions, and has great economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0026] In the present invention, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a mechanical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection of an electrical line or a signal. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In addition, the terms "first", "second", etc. are used only for descriptive purposes and should not be understood as indicating or implying relative importance.

[0028] The term "first" or "second" may explicitly or implicitly indicate the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise explicitly and specifically defined.

[0029] like Figure 1 As shown, a zero-emission device for collecting and purifying sulfur hexafluoride in waste gas of the present invention comprises an air intake recovery pipeline 1, a gas-liquid separation device, a liquid delivery pipeline 2, a gas adsorption emission pipeline 3 and a regeneration pipeline 4; the air outlet of the gas intake recovery pipeline 1 is connected to the air intake at the top of the gas-liquid separation device, the liquid outlet at the bottom of the gas-liquid separation device is connected to the liquid inlet of the liquid delivery pipeline 2, the air intake of the gas adsorption emission pipeline 3 is connected to the exhaust port at the top of the gas-liquid separation device, the air intake of the regeneration pipeline 4 is connected to the gas adsorption emission pipeline 3, and the air outlet of the regeneration pipeline 4 is connected to the air intake of the intake recovery pipeline 1.

[0030] An air intake connector 5, an air intake pressure gauge 6, a precision filter 7, a first recovery solenoid valve 8, a compressor 9, a first one-way valve 10, a first pressure-controlled switch 11, and a second recovery solenoid valve 12 are sequentially arranged on the air intake recovery pipeline 1 along the air flow direction.

[0031] The air inlet and the air outlet of the first recovery solenoid valve 8 are connected to a negative pressure recovery pipe 13 , on which a negative pressure recovery solenoid valve 14 , a vacuum compressor 15 and a second one-way valve 16 are arranged in sequence along the air flow direction.

[0032] The gas-liquid separation device includes a refrigerator 17, a first gas-liquid separation tower 18, and a second gas-liquid separation tower 19 located below the first gas-liquid separation tower 18. A gas-liquid separation solenoid valve 20 is provided between the bottom of the first gas-liquid separation tower 18 and the top of the second gas-liquid separation tower 19; the gas outlet of the intake air recovery pipeline 1 and the gas inlet of the gas adsorption discharge pipeline 3 are both connected to the top of the first gas-liquid separation tower 18; the liquid inlet of the liquid delivery pipeline 2 is connected to the bottom of the second gas-liquid separation tower 19;

[0033] A first instrument pipe 21 is connected to the lower part of the first gas-liquid separation tower 18, and a first instrument valve 22 and a separation tower pressure gauge 23 are provided on the first instrument pipe 21; a liquid level pipe 24 is provided between the top and the bottom of the second gas-liquid separation tower 19, and a liquid level meter 25 is provided on the liquid level pipe 24;

[0034] The refrigerator 17 is connected to the cooling port of the first gas-liquid separation tower 18 through a first refrigeration connecting pipe 26 and a first refrigeration reflux pipe 27, and a first refrigeration solenoid valve 28 is provided on the first refrigeration connecting pipe 26; the refrigerator 17 is connected to the cooling port of the second gas-liquid separation tower 19 through a second refrigeration connecting pipe 29 and a second refrigeration reflux pipe 30, and a second refrigeration solenoid valve 31 is provided on the second refrigeration connecting pipe 29.

[0035] The liquid delivery pipeline 2 is provided with an infusion solenoid valve 32 , a booster 33 , a third one-way valve 34 , a second pressure-controlled switch 35 and a liquid sulfur hexafluoride filling interface 36 in sequence along the liquid flow direction.

[0036] The gas adsorption discharge pipeline 3 is provided with a pressure regulating valve 37, a first exhaust solenoid valve 38, a first adsorption tower 39, a flow regulating needle valve 40, a second exhaust solenoid valve 41, a second adsorption tower 42, a sulfur hexafluoride leakage monitoring sensor 43, a third adsorption tower 44 and an environmental gas discharge port 45 in sequence along the airflow direction. A heating rod 46 is provided in the first adsorption tower 39, and an adsorption tower pressure gauge 47 is connected to the outside of the first adsorption tower 39.

[0037] The air inlet of the regeneration pipeline 4 is connected to the gas adsorption exhaust pipeline 3 between the flow regulating needle valve 40 and the second exhaust solenoid valve 41, and the air outlet of the regeneration pipeline 4 is connected to the air inlet of the precision filter 7 of the gas intake recovery pipeline 1; the regeneration circuit solenoid valve 48 and the air cooler 49 are arranged in sequence on the regeneration pipeline 4 along the air flow direction.

[0038] A method for collecting and purifying sulfur hexafluoride in waste gas and a zero-emission device, comprising the following steps:

[0039] (1) First, the gas-liquid separation solenoid valve 20 is opened, and the first gas-liquid separation tower 18 and the second gas-liquid separation tower 19 are connected; the refrigerator 17 is started, and the first refrigeration solenoid valve 28 and the second refrigeration solenoid valve 31 are opened to refrigerate the first gas-liquid separation tower 18 and the second gas-liquid separation tower 19, thereby reducing the temperature in the first gas-liquid separation tower 18 and the second gas-liquid separation tower 19;

[0040] (2) The air intake connector 5 is connected to the electrical equipment, and the raw material waste gas in the electrical equipment enters the air intake recovery pipeline 1, first passes through the precision filter 7 to filter out moisture, decomposition products, dust and other impurities, passes through the first recovery solenoid valve 8, is pressurized by the compressor 9, and then enters the top of the first gas-liquid separation tower 18 through the first check valve 10 and the second recovery solenoid valve 12, and performs gas-liquid separation in the first gas-liquid separation tower 18; when the pressure of the air intake pressure gauge 6 is lower than 0MPaG, the first recovery solenoid valve 8 is closed, and the first negative pressure recovery solenoid valve 14 and the vacuum compressor 15 are opened. The vacuum compressor 15 is started to perform negative pressure recovery on the waste gas in the electrical equipment to reduce the residual raw material waste gas;

[0041] (3) The pressure of the separation tower pressure gauge 23 is set not to be higher than 3.5 MPaG. When the pressure of the gas after the compressor 9 is increased is higher than 3.5 MPaG, the first pressure-controlled switch 11 sends a signal to cut off the raw material waste gas recovery process, that is, to close the compressor 9 and the second recovery solenoid valve 12;

[0042] (4) The liquid level meter 25 is a flap-type liquid level meter, which can be set to high, medium and low limit alarms. When the sulfur hexafluoride liquid level in the second gas-liquid separation tower 19 is at the medium limit alarm, the exhaust gas recovery process is shut down, that is, the compressor 9 and the second recovery solenoid valve 12 are shut down; when the sulfur hexafluoride liquid level is at the high limit alarm, the refrigerator 17 and the gas-liquid separation solenoid valve 20 are shut down; then the liquid sulfur hexafluoride filling process is started: the liquid sulfur hexafluoride filling port is connected to the cylinder or container, the infusion solenoid valve 32 is opened, and the booster 33 is started, and the liquid sulfur hexafluoride in the second gas-liquid separation tower 19 is directly filled into the external cylinder or container through the liquid delivery pipeline 2; when the second pressure-controlled switch 35 reaches the 3.5MPaG alarm signal, the infusion solenoid valve 32 and the booster 33 are automatically managed to stop the liquid sulfur hexafluoride filling process, and the cylinder or container is replaced and the pressure is released before continuing the filling process;

[0043] (5) After gas-liquid separation, the waste gas is isolated by the gas-liquid separation solenoid valve 20 to the first gas-liquid separation tower 18, and the pressure regulating valve 37 is adjusted to make the gas output pressure in the first gas-liquid separation tower 18 0.3-0.4MPaG; the first exhaust solenoid valve 38 is opened, and the waste gas is adsorbed by the first adsorption tower 39, and the adsorption pressure is 0.3-0.4MPaG. The opening of the flow regulating needle valve 40 is adjusted to control the waste gas flow rate to 60L / min. After the waste gas is adsorbed by the first adsorption tower 39, the sulfur hexafluoride content in the waste gas is less than 200ppm (g / g); then the waste gas enters the second adsorption tower 42 through the second exhaust solenoid valve 41. The adsorption pressure in the second adsorption tower 42 is normal pressure. After the waste gas is treated by the second adsorption tower 42, the sulfur hexafluoride content in the waste gas is 0;

[0044] (6) The sulfur hexafluoride leakage alarm sensor monitors whether the exhaust gas contains sulfur hexafluoride. If so, an alarm is triggered to prompt the replacement or offline treatment of the second adsorption tower 42. The third adsorption tower 44 is the last measure to ensure zero emission of sulfur hexafluoride in the exhaust gas and a spare adsorption tower. When the second adsorption tower 42 is replaced or offline after being saturated with adsorption, the third adsorption tower 44 is temporarily used to ensure that the sulfur hexafluoride content in the exhaust gas discharged from the environmental protection gas discharge port 45 is 0.

[0045] In step (5), after the first adsorption tower 39 is saturated with adsorption, it is regenerated through the regeneration pipeline 4; the regeneration process is as follows: close the first exhaust solenoid valve 38 and the second exhaust solenoid valve 41, start the heating rod 46 to heat the adsorbent in the first adsorption tower 39, and the heating temperature is 150°C-200°C; then open the air cooler 49, the regeneration circuit solenoid valve 48, the first recovery solenoid valve 8 and the second recovery solenoid valve 12, and start the compressor 9 at the same time, the regenerated gas in the first adsorption tower 39 enters the first gas-liquid separation tower 18 through the regeneration pipeline 4 and the air intake recovery pipeline 1, and the refrigerator 17 is turned on during the recovery of the regenerated gas for auxiliary refrigeration; when the pressure of the adsorption tower pressure gauge 47 is lower than 0MPaG, close the first recovery solenoid valve 8, turn on the negative pressure recovery solenoid valve 14 and the vacuum compressor 15, and regenerate the first adsorption tower 39 by vacuum heating.

[0046] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. The working method of the zero-emission equipment for collecting and purifying sulfur hexafluoride in waste gas is characterized by: The sulfur hexafluoride collection and purification and zero-emission equipment in the waste gas comprises an air intake recovery pipeline, a gas-liquid separation device, a liquid delivery pipeline, a gas adsorption discharge pipeline and a regeneration pipeline; the air outlet of the gas intake recovery pipeline is connected to the air intake at the top of the gas-liquid separation device, the liquid outlet at the bottom of the gas-liquid separation device is connected to the liquid inlet of the liquid delivery pipeline, the air intake of the gas adsorption discharge pipeline is connected to the exhaust port at the top of the gas-liquid separation device, the air intake of the regeneration pipeline is connected to the gas adsorption discharge pipeline, and the air outlet of the regeneration pipeline is connected to the air intake of the air intake recovery pipeline; An intake joint, an intake pressure gauge, a precision filter, a first recovery solenoid valve, a compressor, a first one-way valve, a first pressure-controlled switch, and a second recovery solenoid valve are sequentially arranged along the air flow direction of the intake recovery pipeline; The air inlet and the air outlet of the first recovery solenoid valve are connected to a negative pressure recovery pipe, and the negative pressure recovery solenoid valve, the vacuum compressor and the second one-way valve are arranged in sequence on the negative pressure recovery pipe along the air flow direction; The gas-liquid separation device comprises a refrigerator, a first gas-liquid separation tower and a second gas-liquid separation tower located below the first gas-liquid separation tower, a gas-liquid separation solenoid valve is arranged between the bottom of the first gas-liquid separation tower and the top of the second gas-liquid separation tower; the gas outlet of the intake air recovery pipeline and the gas inlet of the gas adsorption discharge pipeline are both connected to the top of the first gas-liquid separation tower; the liquid inlet of the liquid delivery pipeline is connected to the bottom of the second gas-liquid separation tower; The lower part of the first gas-liquid separation tower is connected to a first instrument pipe, on which a first instrument valve and a separation tower pressure gauge are arranged; a liquid level pipe is arranged between the top and the bottom of the second gas-liquid separation tower, on which a liquid level gauge is arranged; The refrigerator is connected to the cooling port of the first gas-liquid separation tower through a first refrigeration connecting pipe and a first refrigeration reflux pipe, and a first refrigeration solenoid valve is provided on the first refrigeration connecting pipe; the refrigerator is connected to the cooling port of the second gas-liquid separation tower through a second refrigeration connecting pipe and a second refrigeration reflux pipe, and a second refrigeration solenoid valve is provided on the second refrigeration connecting pipe; The liquid delivery pipeline is provided with an infusion solenoid valve, a booster, a third one-way valve, a second pressure-controlled switch and a liquid sulfur hexafluoride filling interface in sequence along the liquid flow direction; The gas adsorption discharge pipeline is provided with a pressure regulating valve, a first exhaust solenoid valve, a first adsorption tower, a flow regulating needle valve, a second exhaust solenoid valve, a second adsorption tower, a sulfur hexafluoride leakage monitoring sensor, a third adsorption tower and an environmental gas discharge port in sequence along the airflow direction. A heating rod is provided in the first adsorption tower, and an adsorption tower pressure gauge is connected to the outside of the first adsorption tower. The air inlet of the regeneration pipeline is connected to the gas adsorption exhaust pipeline between the flow regulating needle valve and the second exhaust solenoid valve, and the air outlet of the regeneration pipeline is connected to the air inlet of the precision filter of the gas intake recovery pipeline; the regeneration circuit solenoid valve and the air cooler are arranged in sequence along the air flow direction on the regeneration pipeline; The working method comprises the following steps: (1) First, the gas-liquid separation solenoid valve is opened, and the first gas-liquid separation tower and the second gas-liquid separation tower are connected; the refrigerator is started, and the first refrigeration solenoid valve and the second refrigeration solenoid valve are opened to refrigerate the first gas-liquid separation tower and the second gas-liquid separation tower, thereby reducing the temperature in the first gas-liquid separation tower and the second gas-liquid separation tower; (2) The air intake connector is connected to the electrical equipment. The raw waste gas in the electrical equipment enters the air intake recovery pipeline, is first filtered by a precision filter for water, decomposition products, and dust impurities, passes through the first recovery solenoid valve, is pressurized by the compressor, and then enters the top of the first gas-liquid separation tower through the first check valve and the second recovery solenoid valve. Gas-liquid separation is performed in the first gas-liquid separation tower. When the pressure on the air intake pressure gauge is lower than 0 MPaG, the first recovery solenoid valve is closed, and the first negative pressure recovery solenoid valve and the vacuum compressor are opened. The vacuum compressor is started to perform negative pressure recovery on the waste gas in the electrical equipment to reduce the residual raw waste gas. (3) The pressure gauge of the separation tower shall not be set higher than 3.5MPaG. When the gas pressure after the compressor is increased is higher than 3.5MPaG, the first pressure-controlled switch sends a signal to cut off the raw material waste gas recovery process, that is, shut down the compressor and the second recovery solenoid valve; (4) The liquid level meter is a flap-type liquid level meter with high, medium and low limit alarms. When the sulfur hexafluoride liquid level in the second gas-liquid separation tower is at the medium limit alarm, the waste gas recovery process is shut down, that is, the compressor and the second recovery solenoid valve are shut down; when the sulfur hexafluoride liquid level is at the high limit alarm, the refrigerator and the gas-liquid separation solenoid valve are shut down; then the liquid sulfur hexafluoride filling process is started: the liquid sulfur hexafluoride filling port is connected to the cylinder or container, the infusion solenoid valve is opened, the booster is started, and the liquid sulfur hexafluoride in the second gas-liquid separation tower is directly filled into the external cylinder or container through the liquid delivery pipeline; when the second pressure-controlled switch reaches the 3.5MPaG alarm signal, the infusion solenoid valve and the booster are automatically managed to stop the liquid sulfur hexafluoride filling process, and the cylinder or container is replaced and the pressure is released before continuing the filling process; (5) After gas-liquid separation, the waste gas is isolated by the gas-liquid separation solenoid valve to the first gas-liquid separation tower. The pressure regulating valve is adjusted to make the gas output pressure in the first gas-liquid separation tower 0.3-0.4MPaG; the first exhaust solenoid valve is opened, and the waste gas is adsorbed by the first adsorption tower. The adsorption pressure is 0.3-0.4MPaG. The opening of the flow regulating needle valve is adjusted to control the waste gas flow rate to 60L / min. After the waste gas is adsorbed by the first adsorption tower, the sulfur hexafluoride content in the waste gas is less than 200ppm (g / g); then the waste gas enters the second adsorption tower through the second exhaust solenoid valve. The adsorption pressure in the second adsorption tower is normal pressure. After the waste gas is treated by the second adsorption tower, the sulfur hexafluoride content in the waste gas is 0; (6) The sulfur hexafluoride leakage alarm sensor monitors whether the exhaust gas contains sulfur hexafluoride. If so, it will alarm and prompt the replacement or offline treatment of the second adsorption tower; the third adsorption tower is the last measure to ensure zero emission of sulfur hexafluoride in the exhaust gas and a backup adsorption tower. When the second adsorption tower is replaced or offline after adsorption saturation, the third adsorption tower is temporarily used to ensure that the sulfur hexafluoride content in the exhaust gas discharged from the environmental protection gas discharge port is 0.

2. The working method of the zero-emission equipment for collecting and purifying sulfur hexafluoride in waste gas according to claim 1, characterized in that: In step (5), after the first adsorption tower is saturated with adsorption, regeneration is performed through the regeneration pipeline; the regeneration process is as follows: the first exhaust solenoid valve and the second exhaust solenoid valve are closed, and the heating rod is started to heat the adsorbent in the first adsorption tower, and the heating temperature is 150°C-200°C; then the air cooler, the regeneration circuit solenoid valve, the first recovery solenoid valve and the second recovery solenoid valve are turned on, and the compressor is started at the same time, and the regenerated gas in the first adsorption tower enters the first gas-liquid separation tower through the regeneration pipeline and the air intake recovery pipeline, and the refrigerator is turned on for auxiliary refrigeration during the recovery of the regenerated gas; when the pressure gauge pressure of the adsorption tower is lower than 0MPaG, the first recovery solenoid valve is closed, and the negative pressure recovery solenoid valve and the vacuum compressor are turned on to regenerate the first adsorption tower by vacuum heating.

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