Electrical drive membrane treatment system and method for highly concentrated radioactive liquid waste

Abstract

The present invention discloses an electro-driven membrane treatment system and method for highly concentrated saline radioactive waste liquid. The system includes a concentrated water tank, a fresh water tank, and an electro-driven membrane device. The concentrated water tank is connected to the electro-driven membrane device through a concentrated water pipeline to form a concentrated water circulation. The fresh water tank is connected to the electro-driven membrane device through a fresh water pipeline to form a fresh water circulation. The concentrated water tank is connected to the electro-driven membrane device through a polar water pipeline to form a polar water circulation. The method includes the following steps: pumping the waste liquid into the concentrated water tank and the fresh water tank respectively, enabling the waste liquid in the fresh water tank to form a fresh water circulation between the fresh water tank and the fresh water chamber, enabling the waste liquid in the concentrated water tank to form a concentrated water circulation and a polar water circulation between the concentrated water tank and the concentrated water chamber and the polar water chamber respectively, and starting the operation of the electro-driven membrane device until the waste liquid is treated to the target level. The purpose is to provide an electro-driven membrane treatment system and method for highly concentrated saline radioactive waste liquid, which can effectively avoid the pollution of polar water, thereby avoiding the generation of secondary radioactive waste liquid.

Description

Technical Field

[0001] The invention relates to the field of waste liquid treatment, and in particular to a system and method for treating high-concentration salt radioactive waste liquid. Background Art

[0002] Electrodialysis is a common electrodialysis membrane technology that uses the selective permeability of ion exchange membranes to allow charged ions to migrate in a directional manner under the action of a direct current electric field. It has the remarkable characteristics of low energy consumption and high efficiency. Electrodialysis is a very common electrodialysis membrane technology. In the treatment of radioactive waste liquid, electrodialysis has been partially applied in laboratories. For example, the Chinese Institute of Radiation Protection once used a two-stage two-stage circulating electrodialysis device to treat simulated waste liquid with a NaCl content of 4.68% in the radioactive waste incineration process. The salt concentration of the resulting fresh water was only 186 mg·L -1 The salt content in the concentrate is as high as 86g·L -1 .

[0003] The electric-driven membrane equipment based on electrodialysis can be divided into concentrated water chamber, fresh water chamber and polar water chamber in terms of structure. Its working principle is as follows: Figure 1 As shown in the figure, under the action of the applied DC electric field, ions migrate to the electrode with the opposite charge. During the migration to the electrode, cations (+) will be blocked by anion exchange membrane A; while anions (-) will be blocked by cation exchange membrane C. As a result, a concentrated solution of ions is produced on one side of the membrane, and a desalinated solution of ions is produced on the other side. The feed liquid becomes a concentrated solution after passing through the concentrated water chamber, the feed liquid becomes a desalinated solution after passing through the desalinated water chamber, and the electrode liquid (also called electrode water) flows through the electrode water chamber.

[0004] Usually, the electrode liquid used in the electric drive membrane equipment is sodium sulfate solution. In the process of treating conventional waste liquid, this solution circulates in the polar water chamber, removes the heat generated by the plate, and provides sufficient ion strength for the current transfer process. However, since the polar water chamber is isolated from the fresh water chamber and the concentrated water chamber only by the ion exchange membrane, it is inevitable that the target ions to be treated in the feed liquid will migrate into the polar water during operation. If the migrated ions are nuclide ions, it will cause radioactive contamination of the polar water and become secondary radioactive waste liquid. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a system and method for treating high-concentration salt radioactive waste liquid by using an electric-driven membrane, which can effectively avoid the contamination of polar water, thereby avoiding the generation of secondary radioactive waste liquid.

[0006] The electro-driven membrane treatment system for high-concentration saline radioactive waste liquid in the present invention includes a concentrated water tank, a fresh water tank, and an electro-driven membrane device. The concentrated water tank is connected to the electro-driven membrane device through a concentrated water pipeline to form a concentrated water circulation. The fresh water tank is connected to the electro-driven membrane device through a fresh water pipeline to form a fresh water circulation. The concentrated water tank is connected to the electro-driven membrane device through a polar water pipeline to form a polar water circulation.

[0007] In the electro-driven membrane treatment system for high-concentration saline radioactive waste liquid in the present invention, the concentrated water pipeline, the fresh water pipeline, and the polar water pipeline are all connected to an emptying pipeline.

[0008] In the electro-driven membrane treatment system for high-concentration saline radioactive waste liquid in the present invention, the concentrated water pipeline includes a first concentrated water pipeline and a second concentrated water pipeline. Both the first concentrated water pipeline and the second concentrated water pipeline are connected between the concentrated water tank and the concentrated water chamber of the electro-driven membrane device. The direction of the concentrated water circulation is from the concentrated water tank, passing through the first concentrated water pipeline, the concentrated water chamber of the electro-driven membrane device, and the second concentrated water pipeline in sequence, and then returning to the concentrated water tank. A concentrated water circulation pump and a concentrated water valve are provided on the first concentrated water pipeline, and a concentrated water valve is also provided on the second concentrated water pipeline.

[0009] In the electro-driven membrane treatment system for high-concentration saline radioactive waste liquid in the present invention, a pH sensor, a conductivity sensor, and a pressure gauge are provided on both the first concentrated water pipeline and the second concentrated water pipeline. A first flowmeter is also provided on the first concentrated water pipeline, and a liquid level sensor is provided on the concentrated water tank.

[0010] In the electro-driven membrane treatment system for high-concentration saline radioactive waste liquid in the present invention, the fresh water pipeline includes a first fresh water pipeline and a second fresh water pipeline. Both the first fresh water pipeline and the second fresh water pipeline are connected between the fresh water tank and the fresh water chamber of the electro-driven membrane device. The direction of the fresh water circulation is from the fresh water tank, passing through the first fresh water pipeline, the fresh water chamber of the electro-driven membrane device, and the second fresh water pipeline in sequence, and then returning to the fresh water tank. A fresh water circulation pump and a fresh water valve are provided on the first fresh water pipeline, and a fresh water valve is also provided on the second fresh water pipeline.

[0011] In the electro-driven membrane treatment system for high-concentration saline radioactive waste liquid in the present invention, a pH sensor, a conductivity sensor, and a pressure gauge are provided on both the first fresh water pipeline and the second fresh water pipeline. A second flowmeter is provided on the first fresh water pipeline, and a liquid level sensor is provided on the fresh water tank.

[0012] In the electric drive membrane treatment system for highly concentrated saline radioactive waste liquid of the present invention, the electrode water pipeline includes a first electrode water pipeline and a second electrode water pipeline. One end of the first electrode water pipeline is connected to the first concentrated water pipeline, and the other end of the first electrode water pipeline is connected to the electrode water chamber of the electric drive membrane device. One end of the first electrode water pipeline is located between the concentrated water circulation pump and the first flowmeter. The concentrated water circulation pump is located on the first concentrated water pipeline between one end of the first electrode water pipeline and the concentrated water tank. The first flowmeter, pH sensor, conductivity sensor, and pressure gauge on the first concentrated water pipeline are located between one end of the first electrode water pipeline and the electric drive membrane device. The second electrode water pipeline is connected between the electrode water chamber of the electric drive membrane device and the concentrated water tank. The direction of the electrode water circulation is from the concentrated water tank, passing through a part of the first concentrated water pipeline, the first electrode water pipeline, the electrode water chamber of the electric drive membrane device, and the second electrode water pipeline in sequence, and then returning to the concentrated water tank.

[0013] In the electric drive membrane treatment system for highly concentrated saline radioactive waste liquid of the present invention, a polar water valve, a third flowmeter, a pressure gauge, and a temperature sensor are provided on the first electrode water pipeline, and a temperature sensor is provided on the second electrode water pipeline.

[0014] In the electric drive membrane treatment system for highly concentrated saline radioactive waste liquid of the present invention, both the first electrode water pipeline and the second electrode water pipeline are provided with two in parallel arrangement. The electrode water chambers of the electric drive membrane device are provided with two. One end of each electrode water chamber is respectively connected to a first electrode water pipeline and a second electrode water pipeline. The first concentrated water pipeline, the first fresh water pipeline, and the first electrode water pipeline are all connected to the drain pipeline, and a drain valve is provided on the drain pipeline.

[0015] The method for treating highly concentrated saline radioactive waste liquid by electric drive membrane in the present invention includes the following steps:

[0016] Pump the waste liquid to be treated into the concentrated water tank and the fresh water tank respectively.

[0017] Open the fresh water circulation pump to form a fresh water circulation between the fresh water tank and the fresh water chamber of the electric drive membrane device for the waste liquid in the fresh water tank.

[0018] Open the concentrated water circulation pump, adjust the concentrated water valve and the electrode water valve for water volume distribution, so that the waste liquid in the concentrated water tank forms a concentrated water circulation and an electrode water circulation respectively between the concentrated water tank and the concentrated water chamber and the electrode water chamber of the electric drive membrane device.

[0019] Turn on the power supply of the electric drive membrane device to make the electric drive membrane device start to work until the waste liquid in the concentrated water tank and the fresh water tank is treated to the target level.

[0020] The difference between the system and method for treating highly concentrated radioactive wastewater by electro-driven membrane of the present invention and the prior art is that the present invention uses the concentrated liquid (i.e., the wastewater in the concentrated water tank) as the electrode water, and this method can effectively avoid the pollution of the electrode water, thereby avoiding the generation of secondary radioactive wastewater.

[0021] The present invention will be further described below with reference to the accompanying drawings. Description of the Drawings

[0022] Figure 1 It is the working principle diagram of the electro-driven membrane equipment in the prior art;

[0023] Figure 2 It is the structural schematic diagram of the system for treating highly concentrated radioactive wastewater by electro-driven membrane in the present invention;

[0024] Figure 3 It is the flow chart of the method for treating highly concentrated radioactive wastewater by electro-driven membrane in the present invention. Detailed Embodiments

[0025] As Figure 2 shown, the system for treating highly concentrated radioactive wastewater by electro-driven membrane in the present invention includes a concentrated water tank 2, a fresh water tank 14 and an electro-driven membrane equipment 9. The concentrated water tank 2 is connected to the electro-driven membrane equipment 9 through a concentrated water pipeline to form a concentrated water circulation. The fresh water tank 14 is connected to the electro-driven membrane equipment 9 through a fresh water pipeline to form a fresh water circulation. The concentrated water tank 2 is connected to the electro-driven membrane equipment 9 through an electrode water pipeline to form an electrode water circulation.

[0026] In the system for treating highly concentrated radioactive wastewater by electro-driven membrane in the present invention, the concentrated water pipeline, the fresh water pipeline and the electrode water pipeline are all connected to an emptying pipeline 20.

[0027] In the system for treating highly concentrated radioactive wastewater by electro-driven membrane in the present invention, the concentrated water pipeline includes a first concentrated water pipeline 4 and a second concentrated water pipeline 10. The first concentrated water pipeline 4 and the second concentrated water pipeline 10 are both connected between the concentrated water tank 2 and the concentrated water chamber of the electro-driven membrane equipment 9. The direction of the concentrated water circulation is from the concentrated water tank 2, passing through the first concentrated water pipeline 4, the concentrated water chamber of the electro-driven membrane equipment 9 and the second concentrated water pipeline 10 in sequence, and then returning to the concentrated water tank 2. A concentrated water circulation pump 3 and a concentrated water valve are provided on the first concentrated water pipeline 4, and a concentrated water valve is also provided on the second concentrated water pipeline 10.

[0028] In the system for treating highly concentrated radioactive wastewater by electro-driven membrane in the present invention, a pH sensor 6, a conductivity sensor 7 and a pressure gauge 8 are provided on both the first concentrated water pipeline 4 and the second concentrated water pipeline 10. A first flow meter 5 is also provided on the first concentrated water pipeline 4, and a liquid level sensor 1 is provided on the concentrated water tank 2.

[0029] In the system for treating highly concentrated saline radioactive waste liquid by electro-driven membrane in the present invention, the fresh water pipeline includes a first fresh water pipeline 12 and a second fresh water pipeline 15. Both the first fresh water pipeline 12 and the second fresh water pipeline 15 are connected between the fresh water tank 14 and the fresh water chamber of the electro-driven membrane device 9. The direction of fresh water circulation is from the fresh water tank 14, passing through the first fresh water pipeline 12, the fresh water chamber of the electro-driven membrane device 9, and the second fresh water pipeline 15 in sequence, and then returning to the fresh water tank 14. A fresh water circulation pump 13 and a fresh water valve are provided on the first fresh water pipeline 12, and a fresh water valve is also provided on the second fresh water pipeline 15.

[0030] In the system for treating highly concentrated saline radioactive waste liquid by electro-driven membrane in the present invention, pH sensors 6, conductivity sensors 7, and pressure gauges 8 are provided on both the first fresh water pipeline 12 and the second fresh water pipeline 15. A second flowmeter 11 is provided on the first fresh water pipeline 12, and a liquid level sensor 1 is provided on the fresh water tank 14.

[0031] In the system for treating highly concentrated saline radioactive waste liquid by electro-driven membrane in the present invention, the electrode water pipeline includes a first electrode water pipeline 16 and a second electrode water pipeline 19. One end of the first electrode water pipeline 16 is connected to the first concentrated water pipeline 4 (that is, one end of the first electrode water pipeline 16 is connected to the concentrated water tank 2 through the first concentrated water pipeline 4), and the other end of the first electrode water pipeline 16 is connected to the electrode water chamber of the electro-driven membrane device 9. One end of the first electrode water pipeline 16 is located between the concentrated water circulation pump 3 and the first flowmeter 5. The concentrated water circulation pump 3 is located on the first concentrated water pipeline 4 between one end of the first electrode water pipeline 16 and the concentrated water tank 2. The first flowmeter 5, pH sensor 6, conductivity sensor 7, and pressure gauge 8 on the first concentrated water pipeline 4 are located between one end of the first electrode water pipeline 16 and the electro-driven membrane device 9. The second electrode water pipeline 19 is connected between the electrode water chamber of the electro-driven membrane device 9 and the concentrated water tank 2. The direction of electrode water circulation is from the concentrated water tank 2, passing through a part of the first concentrated water pipeline 4, the first electrode water pipeline 16, the electrode water chamber of the electro-driven membrane device 9, and the second electrode water pipeline 19 in sequence, and then returning to the concentrated water tank 2.

[0032] In the system for treating highly concentrated saline radioactive waste liquid by electro-driven membrane in the present invention, an electrode water valve, a third flowmeter 17, a pressure gauge 8, and a temperature sensor 18 are provided on the first electrode water pipeline 16, and a temperature sensor 18 is provided on the second electrode water pipeline 19.

[0033] In the system for treating highly concentrated saline radioactive waste liquid by electro-driven membrane in the present invention, the first electrode water pipeline 16 and the second electrode water pipeline 19 are both arranged in parallel in two lines. The electrode water chambers of the electro-driven membrane device 9 are provided with two. One first electrode water pipeline 16 and one second electrode water pipeline 19 are respectively connected to both ends of each electrode water chamber. The first concentrated water pipeline 4, the first fresh water pipeline 12 and the first electrode water pipeline 16 are all connected to the evacuation pipeline 20, and an evacuation valve is provided on the evacuation pipeline 20.

[0034] The concentrated water valve, the fresh water valve and the electrode water valve in the present invention are used to adjust the size of the circulating flow rate and distribute the circulating water volumes.

[0035] The flowmeter in the present invention is used to monitor the circulating flow rate data and cooperate with the concentrated water valve, the fresh water valve and the electrode water valve for flow rate adjustment.

[0036] The pH sensor 6, the conductivity sensor 7 and the pressure gauge 8 in the present invention are conventional monitoring means and are used to judge the operating condition of the electro-driven membrane device 9.

[0037] The temperature sensor 18 in the present invention is used to monitor the change of the electrode water temperature. Once the electrode water temperature shows abnormal fluctuations, an alarm is given and the device is even shut down to avoid potential dangers.

[0038] As Figure 3 shown, the method for treating highly concentrated saline radioactive waste liquid by electro-driven membrane in the present invention includes the following steps:

[0039] Pump the waste liquid to be treated into the concentrated water tank 2 and the fresh water tank 14 respectively.

[0040] Open the fresh water circulation pump 13 to form a fresh water circulation between the fresh water tank 14 and the fresh water chamber of the electro-driven membrane device 9 for the waste liquid in the fresh water tank 14.

[0041] Open the concentrated water circulation pump 3, adjust the concentrated water valve and the electrode water valve for water volume distribution, so that the waste liquid in the concentrated water tank 2 forms a concentrated water circulation and an electrode water circulation respectively between the concentrated water tank 2 and the concentrated water chamber and the electrode water chamber of the electro-driven membrane device 9.

[0042] Turn on the power supply of the electro-driven membrane device 9 to make the electro-driven membrane device 9 start to work until the waste liquid in the concentrated water tank 2 and the waste liquid in the fresh water tank 14 are treated to the target level.

[0043] The present invention uses the concentrated liquid (i.e., the waste liquid in the concentrated water tank 2) as the electrode water (i.e., the electrode liquid). This method can effectively avoid the pollution of the electrode water, thereby avoiding the generation of secondary radioactive waste liquid.

[0044] In the present invention, the concentrated liquid in the concentrated water tank 2 (i.e., the waste liquid in the concentrated water tank 2) is used as the electrode plate electrode water to replace the original electrode water, avoiding the contamination of the original electrode water by radioactive substances during the circulation process, thereby avoiding the generation of secondary radioactive waste liquid. In the present invention, in order to use the concentrated liquid to replace the electrode water, first, the concentration of the concentrated liquid needs to reach a relatively high level to provide sufficient current density. Second, the concentrated liquid should not contain ionic components that are likely to deposit on the electrode plate and cause electrode poisoning.

[0045] Since radioactive waste liquid is usually processed in batches, the circulation mode in the present invention can effectively avoid the increase in the temperature of the electrode water, and the heat exchange device for cooling the electrode water can be further eliminated, making the system more concise.

[0046] In the present invention, the volumes of the radioactive waste liquid in the fresh water tank 14 and the concentrated water tank 2 are set according to the target concentration multiple. For example, when the target concentration multiple of the concentrated liquid is 10, the volume ratio of the concentrated water tank 2 to the fresh water tank 14 is 1:10. Generally, it is necessary to ensure that the concentrated water circulation flow rate and the fresh water circulation flow rate are consistent. It should be noted that the present invention is only applicable to the treatment of radioactive waste liquid that does not contain high levels of easily precipitable substances or substances that are likely to cause electrode poisoning.

[0047] The beneficial effect of the present invention is that it can effectively avoid the generation of secondary radioactive waste liquid caused by using electrode water represented by sodium sulfate.

[0048] The following is an example of treating radioactive waste liquid containing 0.1 mol / L nitric acid for illustration:

[0049] As Figure 2 shown, first, the waste liquid is respectively injected into the concentrated water tank 2 and the fresh water tank 14, and the volumes of the waste liquid in the concentrated water tank 2 and the fresh water tank 14 are 1 m 3 and 10 m 3 . Then, the fresh water circulation pump 13 is turned on, and the fresh water flow rate is adjusted to 10 m 3 / h. Then, the concentrated water circulation pump 3 is turned on, and the concentrated water circulation flow rate is adjusted to 10 m 3 / h. The circulation flow rates of the two electrode water chambers are both 1.5 m 3 / h. Then, the power supply of the electro-driven membrane device 9 is turned on to carry out waste liquid treatment.

[0050] As the operation time increases, it can be jointly judged by the conductivity sensors 7 and the pH sensors 6 at the inlets of the concentrated water chamber and the fresh water chamber whether the waste liquid treatment end point is reached. After 5 h of normal operation, the nitric acid concentration in the fresh water of the qualified waste liquid is 0.01 mol / L, and the nitric acid concentration in the concentrated water is 1 mol / L.

[0051] During operation, the thermometers at the inlet and outlet of the electrode water chamber can detect a weak temperature difference, which is less than 1°C. After the electrode water returns to the concentrated water tank 2, the heat is further consumed. When batch-treating this batch of radioactive waste liquid in the normal sequence, the waste liquid can be treated to the up-to-standard level in 5 hours, and the temperature of the 1m 3 concentrate does not rise by more than 5°C, which is within the acceptable range.

[0052] The embodiments described above are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. An electric drive membrane treatment system for high-concentration radioactive liquid waste, characterized in that: It includes a concentrated water tank, a fresh water tank and an electrodialysis reversal (EDR) device. The concentrated water tank is connected to the EDR device through a concentrated water pipeline to form a concentrated water circulation. The fresh water tank is connected to the EDR device through a fresh water pipeline to form a fresh water circulation. The concentrated water tank is connected to the EDR device through an electrode water pipeline to form an electrode water circulation. The concentrated water pipeline includes a first concentrated water pipeline and a second concentrated water pipeline. The electrode water pipeline includes a first electrode water pipeline and a second electrode water pipeline. One end of the first electrode water pipeline is connected to the first concentrated water pipeline, and the other end of the first electrode water pipeline is connected to the electrode water chamber of the EDR device. The second electrode water pipeline is connected between the electrode water chamber of the EDR device and the concentrated water tank.

2. The electro-driven membrane treatment system for high-concentration saline radioactive waste liquid according to claim 1, wherein: The concentrated water pipeline, the fresh water pipeline and the electrode water pipeline are all connected to an exhaust pipeline.

3. The electro-driven membrane treatment system for highly concentrated radioactive liquid waste according to claim 2, wherein: Both the first concentrated water pipeline and the second concentrated water pipeline are connected between the concentrated water tank and the concentrated water chamber of the EDR device. The direction of the concentrated water circulation is from the concentrated water tank, passing through the first concentrated water pipeline, the concentrated water chamber of the EDR device and the second concentrated water pipeline in sequence, and then returning to the concentrated water tank. A concentrated water circulation pump and a concentrated water valve are provided on the first concentrated water pipeline, and a concentrated water valve is also provided on the second concentrated water pipeline.

4. The high-concentration salt radioactive waste liquid system for electro-driven membrane treatment according to claim 3, characterized in that: A pH sensor, a conductivity sensor and a pressure gauge are provided on both the first concentrated water pipeline and the second concentrated water pipeline. A first flowmeter is also provided on the first concentrated water pipeline, and a level sensor is provided on the concentrated water tank.

5. The electric drive membrane treatment high-concentration radioactive waste liquid system according to claim 4, characterized in that: The fresh water pipeline includes a first fresh water pipeline and a second fresh water pipeline. Both the first fresh water pipeline and the second fresh water pipeline are connected between the fresh water tank and the fresh water chamber of the EDR device. The direction of the fresh water circulation is from the fresh water tank, passing through the first fresh water pipeline, the fresh water chamber of the EDR device and the second fresh water pipeline in sequence, and then returning to the fresh water tank. A fresh water circulation pump and a fresh water valve are provided on the first fresh water pipeline, and a fresh water valve is also provided on the second fresh water pipeline.

6. The electro-driven membrane treatment system for high-concentration saline radioactive waste liquid according to claim 5, wherein: A pH sensor, a conductivity sensor and a pressure gauge are provided on both the first fresh water pipeline and the second fresh water pipeline. A second flowmeter is provided on the first fresh water pipeline, and a level sensor is provided on the fresh water tank.

7. The electric drive membrane treatment system for highly concentrated saline radioactive waste liquid according to claim 6, wherein: One end of the first electrode water pipeline is located between the concentrated water circulation pump and the first flowmeter. The concentrated water circulation pump is located on the first concentrated water pipeline between one end of the first electrode water pipeline and the concentrated water tank. The first flowmeter, pH sensor, conductivity sensor and pressure gauge on the first concentrated water pipeline are located between one end of the first electrode water pipeline and the EDR device. The direction of the electrode water circulation is from the concentrated water tank, passing through a part of the first concentrated water pipeline, the first electrode water pipeline, the electrode water chamber of the EDR device and the second electrode water pipeline in sequence, and then returning to the concentrated water tank.

8. The electric drive membrane treatment system for high-concentration radioactive liquid waste according to claim 7, characterized in that: An electrode water valve, a third flowmeter, a pressure gauge and a temperature sensor are provided on the first electrode water pipeline, and a temperature sensor is provided on the second electrode water pipeline.

9. The electro-driven membrane treatment system for highly concentrated saline radioactive waste liquid according to claim 8, wherein: Both the first electrode water pipeline and the second electrode water pipeline are arranged in two parallel lines. The electrode water chamber of the EDR device is provided with two. One end of each electrode water chamber is respectively connected with a first electrode water pipeline and a second electrode water pipeline. The first concentrated water pipeline, the first fresh water pipeline and the first electrode water pipeline are all connected to the exhaust pipeline, and an exhaust valve is provided on the exhaust pipeline.

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