Radioactive waste gas treatment system and treatment method

Abstract

The invention relates to a radioactive waste gas treatment system and method, and the system comprises a retention device, a humidification device, an electrolysis device, and a carbon dioxide removal device. The retention device is provided with a gas inlet used for introducing waste gas needing to be treated, and a gas outlet of the retention device is communicated with the gas inlet of the humidification device and used for removing inert gas in the waste gas; a gas outlet of the humidifying device is communicated with a gas phase inlet of the electrolysis device, and humidified gas enters the space between the anode plate and the anode electrode; a gas phase outlet of the electrolysis device is communicated with an inlet of the carbon dioxide removal equipment and is used for completely oxidizing hydrogen and methane in the waste gas; and the carbon dioxide removal equipment is used for removing carbon dioxide in the gas output by the electrolysis device. Methane and hydrogen in the waste gas are oxidized and removed through the electrolysis device, so that potential safety hazards existing during high-temperature reaction or oxygen introduction are avoided, methane and hydrogen are removed in an electrolytic oxidation mode, and the method has the advantage of being high in reaction rate.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear industry waste gas treatment, and in particular to a radioactive waste gas treatment system and a treatment method. Background Art

[0002] The atoms of carbon, nitrogen, oxygen and other elements in the media such as the moderator / coolant, nuclear fuel and primary circuit materials of nuclear power plant reactors will produce radioactive nuclides carbon-14 under the bombardment of high-energy neutrons. The gaseous carbon-14 of pressurized water reactors mainly comes from the hydrogen-containing waste gas of the primary circuit during the overhaul of the unit, which mainly includes 14 CO2 (5-25%) and 14 CH4 (75-95%). 14 CO2 is highly reactive and can be eliminated by absorption by alkaline substances; however, 14 CH4 molecules are highly symmetrical and weakly polar, making it difficult to remove them efficiently through adsorption. The International Atomic Energy Agency (IAEA) recommends that CH4 in waste gas be removed by 14 CH4 is first converted into chemically more active 14 CO2, and then proceed to the next step.

[0003] The existing 14 CH4 is converted to 14 The methods for CO2 mainly include direct combustion, plasma oxidation, thermal catalytic oxidation and photocatalytic oxidation. The combustion method is suitable for high concentrations of 14 CH4, while the hydrogen-containing waste gas of pressurized water reactor 14 The concentration of CH4 is less than 1%, so direct combustion is not suitable for this scenario. Plasma oxidation can be used for low concentration 14 Oxidation of CH4, but oxygen needs to be introduced into the reaction system; data show that hydrogen accounts for about 30%-80% of the hydrogen-containing waste gas of pressurized water reactors (covering the explosion limit range of hydrogen), and the remaining components are 14 CO2 (5-25%) and 14 CH4 (75-95%), so the introduction of oxygen may cause hydrogen explosion. In addition, plasma will convert oxygen into harmful ozone; thermal catalytic oxidation can only achieve a higher conversion rate at high temperature (>300℃) and in the presence of oxygen, but high temperature may cause fire. Similarly, the introduction of oxygen will also increase the risk of hydrogen explosion. Photocatalytic method can be used for low concentration 14 The oxidation of CH4, however, the low reaction rate makes the processing rate slow and cannot meet the needs of practical engineering applications. How to safely and efficiently remove low-concentration methane in exhaust gas has become an urgent problem to be solved. Summary of the invention

[0004] The invention discloses a radioactive waste gas treatment system and a treatment method, aiming to solve the technical problems existing in the prior art.

[0005] The present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a radioactive waste gas treatment system, characterized in that it includes a retention device, a humidifying device, an electrolysis device and a carbon dioxide removal device; the retention device has an air inlet for introducing the waste gas to be treated, and the air outlet of the retention device is connected to the air inlet of the humidifying device and is used to remove the inert gas in the waste gas; the air outlet of the humidifying device is connected to the gas phase inlet of the electrolysis device, and the humidified gas enters between the anode plate and the anode electrode; the gas phase outlet of the electrolysis device is connected to the inlet of the carbon dioxide removal device and is used to completely oxidize the hydrogen and methane in the waste gas; the carbon dioxide removal device is used to remove carbon dioxide in the gas output by the electrolysis device.

[0007] In a radioactive waste gas treatment system of the present invention, the retention device is a long tubular structure with an air inlet and an air outlet at both ends, and is filled with adsorption material; the adsorption material is used to adsorb inert gas in the waste gas.

[0008] In a radioactive waste gas treatment system of the present invention, the retention device comprises an arc tube.

[0009] In a radioactive waste gas treatment system of the present invention, the humidification device includes an air intake main pipe, a first branch pipe, a second branch pipe and a water tank; the air intake main pipe is connected to the air outlet of the retention device; one end of the first branch pipe and the second branch pipe are respectively connected to the air intake main pipe, and the other end of the first branch pipe is connected to the gas phase inlet of the electrolysis device; the other end of the second branch pipe is connected to the air inlet of the water tank; the air inlet of the water tank is located below the water surface, and the gas phase outlet of the water tank is connected to the first branch pipe.

[0010] In a radioactive waste gas treatment system of the present invention, the humidification device also includes a first flow meter, a second flow meter and a control valve; the first flow meter is installed on the air intake main pipe, and is used to measure the gas flow in the air intake main pipe; the second flow meter is installed on the first branch pipe or the second branch pipe, and is used to measure the gas flow in the first branch pipe or the second branch pipe; the control valve is installed on the first branch pipe or the second branch pipe, and is used to adjust the gas flow in the first branch pipe or the second branch pipe.

[0011] In a radioactive waste gas treatment system of the present invention, the electrolysis device includes an anode plate, an anode electrode, an ion exchange membrane, a cathode electrode and a cathode plate; the anode plate and the anode electrode are spaced apart to form a space for gas to pass through; the ion exchange membrane is arranged between the anode electrode and the cathode electrode; the cathode electrode and the ion exchange membrane are spaced apart to form a space for electrolyte to pass through; the cathode plate is attached to the surface of the cathode electrode away from the ion exchange membrane.

[0012] In a radioactive waste gas treatment system of the present invention, a plurality of the electrolysis devices are included; the plurality of the electrolysis devices are stacked.

[0013] In a radioactive waste gas treatment system of the present invention, it also includes a monitoring device and a conveying device; the monitoring device is used to monitor the gas composition at the gas outlet of the electrolysis device; the inlet of the conveying device is connected to the gas outlet of the electrolysis device, and the outlet is connected to the inlet of the humidification device.

[0014] In a second aspect, the present invention further provides a method for treating waste gas using any of the above-mentioned treatment systems, the method comprising:

[0015] Passing the waste gas into the treatment system and into the retention device to remove the inert gas from the waste gas;

[0016] Then, the exhaust gas is passed into a humidifying device to humidify the exhaust gas;

[0017] Then, it is passed into an electrolysis device to oxidize the methane and hydrogen in the exhaust gas into carbon dioxide and water;

[0018] Then, it passes through the carbon dioxide removal equipment and is discharged.

[0019] In the treatment method of the present invention, the relative humidity of the waste gas after being humidified by the humidifying device is 60-80%.

[0020] In the treatment method of the present invention, the electrolyte in the electrolysis device is a potassium salt or sodium salt solution.

[0021] In the processing method of the present invention, a gas detection step is also included;

[0022] The exhaust gas at the outlet of the electrolysis device is monitored by a monitoring device.

[0023] If the monitoring result is qualified, the waste gas will be sent to the subsequent carbon dioxide removal equipment for treatment.

[0024] If the monitoring result is unqualified, the conveying equipment will circulate the exhaust gas to the air inlet of the humidifying device for humidification again.

[0025] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0026] The present invention mainly provides a radioactive waste gas treatment system, which is based on the use of an electrolysis device to oxidize and remove methane and hydrogen in the waste gas, thereby avoiding the safety hazards that exist when high-temperature reactions or the introduction of oxygen, and removing methane and hydrogen by electrolytic oxidation, with a high reaction rate; based on the use of a humidifying device to humidify the waste gas entering the electrolysis device, the methane and hydrogen in the waste gas can exist in the electrolysis device in the form of gas phase and undergo oxidation reaction, thereby improving the reaction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings:

[0028] Figure 1 It is a structural schematic diagram of a radioactive waste gas treatment system of the present invention;

[0029] Figure 2 This is one of the structural schematic diagrams of the humidifying device of the present invention;

[0030] Figure 3 It is a schematic structural diagram of the retention device of the present invention;

[0031] Figure 4 It is a structural schematic diagram of the electrolysis device of the present invention;

[0032] Figure 5 This is the second structural schematic diagram of the humidifying device of the present invention.

[0033] Description of reference numerals:

[0034] 1. Retention device; 2. Humidification device; 21. Air intake main pipe; 22. First branch pipe; 23. Second branch pipe; 24. Water tank; 25. Ejector; 26. First flow meter; 27. Second flow meter; 28. Control valve; 3. Electrolysis device; 31. Anode plate; 32. Anode electrode; 33. Ion exchange membrane; 34. Cathode electrode; 35. Cathode plate; 4. Carbon dioxide removal equipment; 5. Monitoring equipment; 6. Transportation equipment. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a magnetic connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three or more, etc., unless otherwise clearly and specifically limited.

[0037] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In order to solve the problems existing in the prior art, the embodiments of the present application provide a radioactive waste gas treatment system and a treatment method.

[0039] Example 1

[0040] This embodiment provides a radioactive waste gas treatment system, such as Figure 1 As shown, it includes a retention device 1, a humidifying device 2, an electrolysis device 3 and a carbon dioxide removal device 4; the retention device 1 has an air inlet for introducing the external exhaust gas to be treated, and the air outlet of the retention device 1 is connected to the air inlet of the humidifying device 2, which is used to remove inert gases in the exhaust gas, such as trace amounts of krypton and xenon; the air outlet of the humidifying device 2 is connected to the gas phase inlet of the electrolysis device 3, and the humidified gas enters between the anode plate 31 and the anode electrode 32; the gas phase outlet of the electrolysis device 3 is connected to the inlet of the carbon dioxide removal device 4, and is used to completely oxidize the hydrogen and methane in the exhaust gas; the carbon dioxide removal device 4 is used to remove carbon dioxide from the gas output by the electrolysis device 3.

[0041] A radioactive waste gas treatment system of the present invention is based on the use of an electrolysis device 3 to oxidize and eliminate methane and hydrogen in the waste gas, thereby avoiding the potential safety hazards of high temperature reaction or introduction of oxygen, and eliminating methane and hydrogen by electrolytic oxidation at a rate greater than 1m 3 / h; Based on the humidification of the exhaust gas entering the electrolysis device 3 by the humidifier 2, the methane and hydrogen in the exhaust gas can exist in the gas phase in the electrolysis device 3 and undergo oxidation reaction, thereby improving the diffusion efficiency and catalytic efficiency, and then improving 14The CH4 elimination efficiency is high, and there is no risk of hydrogen explosion, which greatly improves the safety and reliability of the hydrogen-containing waste gas treatment process.

[0042] In some preferred embodiments, Figure 1 and 3 As shown, the retention device 1 is a long tubular structure with good pressure resistance, with an air inlet and an air outlet at both ends, and is filled with adsorption materials such as activated carbon or molecular sieves; the adsorption material is used to adsorb inert gases in the exhaust gas.

[0043] In some preferred embodiments, the retention device 1 comprises an arc-shaped pipe. By adopting the arc-shaped pipe, the occupied space can be saved and the channeling phenomenon can be reduced.

[0044] Preferably, the retention device 1 is a spiral tubular structure; based on this, the space utilization can be maximized and the channeling phenomenon can be minimized.

[0045] In some preferred embodiments, the humidifying device 2 is a water tank or a spray humidifying device. Preferably, the humidifying device 2 is a humidifying device with a temperature regulating function to adjust the relative humidity of the gas at the outlet; specifically, Figure 5 As shown, the humidifying device 2 includes a water tank 201, a heating element 202, a humidity measuring element 203 and a control element 204; wherein the heating element 202 is used to heat the liquid in the water tank 201, such as a heating belt; the air inlet of the water tank 201 is connected to the outlet of the retention device 1, the humidity measuring element 203 is used to measure the gas humidity at the air outlet of the water tank 201, and the control element 204 is connected to the humidity measuring element 203 and the heating element 202 to control the heating power of the heating element 202 based on the humidity value measured by the humidity measuring element 203, such as increasing the heating power of the heating element 202 when the humidity value is lower than the required value, thereby achieving humidity control; the control element 204 can be a PLC controller or a DCS control system.

[0046] In some preferred embodiments, Figure 2 As shown, the humidifying device 2 includes an air intake main pipe 21, a first branch pipe 22, a second branch pipe 23 and a water tank 24; the air intake main pipe 21 is connected to the air outlet of the retention device 1; one end of the first branch pipe 22 and the second branch pipe 23 are respectively connected to the air intake main pipe 21, and the other end of the first branch pipe 22 is connected to the gas phase inlet of the electrolysis device 3; the other end of the second branch pipe 23 is connected to the air intake of the water tank 24; the air intake of the water tank 24 is located below the water surface, and the gas phase outlet of the water tank 24 is connected to the first branch pipe 22; based on humidifying a part of the exhaust gas, compared with the method of passing all the exhaust gas into the water tank 24 for humidification, the pressure drop is lower, thereby reducing energy loss; preferably, the relative humidity of the gas at the outlet of the water tank 24 is 80%.

[0047] Preferably, the humidifying device 2 also includes an ejector 25, the inlet of the ejector 25 is connected to the other end of the first branch pipe 22, the outlet is connected to the gas phase inlet of the electrolysis device 3, and the ejector fluid inlet of the ejector 25 is connected to the gas phase outlet of the water tank 24; based on adding the ejector 25, the two gases are mixed by the ejector 25, which can improve the uniformity of humidification.

[0048] In some preferred embodiments, the humidifying device 2 also includes a first flow meter 26, a second flow meter 27 and a control valve 28; the first flow meter 26 is installed on the intake manifold 21, and is used to measure the gas flow in the intake manifold 21; the second flow meter 27 is installed on the first branch pipe 22 or the second branch pipe 23, and is used to measure the gas flow in the first branch pipe 22 or the second branch pipe 23; the control valve 28 is installed on the first branch pipe 22 or the second branch pipe 23, and is used to adjust the gas flow in the first branch pipe 22 or the second branch pipe 23; based on the first flow meter 26 and the second flow meter 27, the gas flow in the first branch pipe 22 and the second branch pipe 23 is measured, and the relative humidity of the gas at the outlet of the final ejector 25 can be calculated, and the flow can be adjusted by the control valve 28, so that the relative humidity of the exhaust gas entering the electrolysis device 3 can be controlled to maintain the electrolysis efficiency of the electrolysis device 3.

[0049] In some preferred embodiments, Figure 4 As shown, the electrolysis device 3 includes an anode plate 31, an anode electrode 32, an ion exchange membrane 33, a cathode electrode 34 and a cathode plate 35; the anode plate 31 and the anode electrode 32 are arranged at intervals, and a space for gas to pass through is formed therebetween; the ion exchange membrane 33 is arranged between the anode electrode 32 and the cathode electrode 34 to isolate the two and avoid short circuit, such as being arranged on the surface of the anode electrode 32 away from the anode plate 31; the cathode electrode 34 and the ion exchange membrane 33 are arranged at intervals, and a space for electrolyte to pass through is formed therebetween; the cathode plate 35 is attached to the surface of the cathode electrode 34 away from the ion exchange membrane 33; there is no electrolyte between the anode plate 31 and the anode electrode 32, but water vapor in the exhaust gas condenses on the surface of the anode electrode 32 to produce a water film, thereby realizing the oxidation reaction of methane and hydrogen; specifically, the space for electrolyte to pass through formed between the cathode electrode 34 and the ion exchange membrane 33 has a liquid inlet and a liquid outlet for transporting the electrolyte.

[0050] The reactions at the anode and cathode in the electrolysis device 3 are as follows:

[0051] Cathode reaction formula: 10H2O+10e - →10OH - +5H2;

[0052] Anode reaction equation 1: 14 CH4+8OH - -8e - → 14CO2+6H2O;

[0053] Anode reaction 2: H2+2OH - -2e - →2H2O;

[0054] Overall reaction formula: 4H2O+ 14 CH4→4H2+ 14 CO2.

[0055] Preferably, the gas flow rate of the electrolysis device 3 is 0-100m 3 / h; working voltage is greater than 0 and less than or equal to 100V; working current is greater than 0 and less than or equal to 100A; during operation, 14 The input voltage, current and gas flow of the electrolysis device are adjusted according to the conversion rate of CH4. When the conversion rate is lower than 99.9%, the anode voltage and current are increased, or the inlet flow of the electrolysis device is reduced.

[0056] In some preferred embodiments, a plurality of electrolysis devices 3 are included; the plurality of electrolysis devices 3 are stacked; the waste gas treatment capacity can be increased based on the arrangement of the plurality of stacked electrolysis devices 3; for example, the number of stacked layers is greater than 0 and less than or equal to 100.

[0057] In some preferred embodiments, Figure 1 As shown, it also includes a monitoring device 5 and a conveying device 6; the monitoring device 5 is used to monitor the gas composition at the gas outlet of the electrolysis device 3, and the monitoring 14 The inlet of the conveying device 6 is connected to the gas outlet of the electrolysis device 3, and the outlet is connected to the inlet of the humidification device 2.

[0058] Specifically, the monitoring device 5 is a gas chromatograph or a high-precision gas detector or a gas chromatograph-gas spectrometer.

[0059] Specifically, valves are respectively provided on the inlet pipeline of the carbon dioxide removal device 4 and the inlet pipeline of the transportation device 6 to control opening and closing. Preferably, the valves are program-controlled valves.

[0060] Specifically, the conveying device 6 is an air pump.

[0061] In some preferred embodiments, the carbon dioxide removal device 4 is an absorption removal or adsorption removal device; when adsorption removal is selected, a dehydration device should also be provided to remove water during the removal of carbon dioxide to avoid affecting the adsorption performance of the carbon dioxide adsorbent.

[0062] Example 2

[0063] This embodiment provides a method for treating waste gas using the treatment system of the above embodiment 1, the method comprising:

[0064] The waste gas is passed into the treatment system and into the retention device 1 to remove the inert gas in the waste gas;

[0065] Then, the exhaust gas is passed into the humidifying device 2 to humidify the exhaust gas;

[0066] Then, the waste gas is passed into the electrolysis device 3 to oxidize the methane and hydrogen in the waste gas into carbon dioxide and water; optionally, the electrolyte of the electrolysis device 3 is an inorganic salt solution, such as an aqueous solution of sulfate, chloride, phosphate and nitrate of lithium, sodium, potassium and cesium;

[0067] Then, after passing through the carbon dioxide removal device 4, it is discharged.

[0068] The treatment method of the present invention is based on the use of an electrolysis device 3 to oxidize and remove methane and hydrogen from the waste gas, thereby avoiding the safety hazards that exist when high-temperature reactions or the introduction of oxygen are performed, and removing methane and hydrogen by electrolytic oxidation has a high reaction rate; based on the use of a humidifying device 2 to humidify the waste gas entering the electrolysis device 3, the waste gas can exist in the electrolysis device 3 in the form of a gas phase, and an oxidation reaction can occur, thereby improving the reaction efficiency.

[0069] In some preferred embodiments, the relative humidity of the exhaust gas after humidification by the humidifying device 2 is 60-80%; too low a relative humidity will cause insufficient wetting of the catalyst on the surface of the anode electrode 32, resulting in a decrease in the electrolysis rate; too high a relative humidity will cause excessive water on the catalyst surface, which is not conducive to the diffusion of CH4 and H2 gases, and thus is not conducive to the electrolysis; optionally, the anode electrode 32 is a catalyst coating of a material having electrocatalytic oxidation of methane and hydrogen, and the catalyst includes but is not limited to nickel-based, iron-based, cobalt-based, and precious metals (platinum, gold, palladium, etc.); the cathode electrode 34 is a catalyst coating of a material having electrocatalytic hydrogen evolution activity, and the catalyst includes but is not limited to nickel-based, iron-based, cobalt-based, molybdenum-based, precious metals (platinum, palladium, ruthenium, etc.), and carbon materials.

[0070] In some preferred embodiments, the electrolyte in the electrolysis device 3 is a potassium salt or sodium salt solution; selecting a potassium salt or sodium salt aqueous solution as the electrolyte can achieve high oxidation efficiency and economy.

[0071] In some preferred embodiments, a gas detection step is also included;

[0072] The exhaust gas from the outlet of the electrolysis device 3 is monitored by the monitoring device 5.

[0073] If the monitoring result is qualified (such as methane activity in the gas <1 Bq / g), the waste gas is sent to the subsequent carbon dioxide removal equipment 4 for treatment.

[0074] If the monitoring result is unqualified, the conveying device 6 circulates the exhaust gas to the air inlet of the humidifying device 2 for humidification again.

[0075] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A radioactive waste gas treatment system, characterized in that: It includes a retention device, a humidification device, an electrolysis device and a carbon dioxide removal device; The retention device has an air inlet for introducing the waste gas to be treated, and the air outlet of the retention device is connected to the air inlet of the humidifying device and is used to remove the inert gas in the waste gas; The gas outlet of the humidifying device is connected to the gas phase inlet of the electrolysis device, and the humidified gas enters between the anode plate and the anode electrode; The gas phase outlet of the electrolysis device is connected to the inlet of the carbon dioxide removal device and is used to completely oxidize the hydrogen and methane in the exhaust gas; The carbon dioxide removal equipment is used to remove carbon dioxide from the gas output by the electrolysis device.

2. A radioactive waste gas treatment system according to claim 1, characterized in that: The retention device is a long tubular structure, with an air inlet and an air outlet at both ends, and is filled with adsorption material; The adsorbent material is used for adsorbing the inert gas in the exhaust gas.

3. A radioactive waste gas treatment system according to claim 2, characterized in that: The retention device includes an arc-shaped tube.

4. A radioactive waste gas treatment system according to claim 1, characterized in that: The humidifying device comprises an air intake main pipe, a first branch pipe, a second branch pipe and a water tank; The air intake manifold is connected to the air outlet of the retention device; One end of the first branch pipe and the second branch pipe are respectively connected to the intake manifold, and the other end of the first branch pipe is connected to the gas phase inlet of the electrolysis device; The other end of the second branch pipe is connected to the air inlet of the water tank; The air inlet of the water tank is located below the water surface, and the gas phase outlet of the water tank is connected to the first branch pipe.

5. A radioactive waste gas treatment system according to claim 4, characterized in that: The humidifying device also includes a first flow meter, a second flow meter and a control valve; The first flow meter is installed in the intake manifold and is used to measure the gas flow in the intake manifold; The second flow meter is installed on the first branch pipe or the second branch pipe, and is used to measure the gas flow in the first branch pipe or the second branch pipe; The control valve is installed on the first branch pipe or the second branch pipe, and is used to adjust the gas flow in the first branch pipe or the second branch pipe.

6. A radioactive waste gas treatment system according to claim 1, characterized in that: The electrolysis device comprises an anode plate, an anode electrode, an ion exchange membrane, a cathode electrode and a cathode plate; The anode plate and the anode electrode are spaced apart to form a space for gas to pass through; The ion exchange membrane is disposed between the anode electrode and the cathode electrode; The cathode electrode and the ion exchange membrane are spaced apart to form a space for electrolyte to pass through; The cathode plate is attached to the surface of the cathode electrode away from the ion exchange membrane.

7. A radioactive waste gas treatment system according to claim 1, characterized in that: It comprises a plurality of the electrolysis devices; the plurality of the electrolysis devices are stacked.

8. A radioactive waste gas treatment system according to claim 1, characterized in that: It also includes monitoring equipment and delivery equipment; The monitoring device is used to monitor the gas composition at the gas outlet of the electrolysis device; The inlet of the conveying device is connected to the gas outlet of the electrolysis device, and the outlet is connected to the inlet of the humidification device.

9. A method for treating waste gas using the treatment system described in any one of claims 1 to 8, characterized in that: The method comprises: Passing the waste gas into the treatment system and into the retention device to remove the inert gas from the waste gas; Then, the exhaust gas is passed into a humidifying device to humidify the exhaust gas; Then, it is passed into an electrolysis device to oxidize the methane and hydrogen in the exhaust gas into carbon dioxide and water; Then, it passes through the carbon dioxide removal equipment and is discharged.

10. The processing method according to claim 9, characterized in that: The relative humidity of the exhaust gas after being humidified by the humidifying device is 60-80%.

11. The processing method according to claim 9, characterized in that: The electrolyte in the electrolysis device is a potassium salt or sodium salt solution.

12. The processing method according to claim 9, characterized in that: Also included is a gas detection step; The exhaust gas at the outlet of the electrolysis device is monitored by a monitoring device. If the monitoring result is qualified, the waste gas will be sent to the subsequent carbon dioxide removal equipment for treatment. If the monitoring result is unqualified, the conveying equipment will circulate the exhaust gas to the air inlet of the humidifying device for humidification again.

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