Helium purification system and operation method

Abstract

The present invention discloses a helium purification system and an operation method. In the helium purification system of the present invention, the first unit converts hydrogen and carbon monoxide in the helium to be purified into water vapor and carbon dioxide respectively; the second unit and the third unit remove water and carbon dioxide respectively by means of condensation separation; the fourth unit is used to remove the remaining impurities in the helium and output pure helium; the first pipeline can send the pure helium back and is used to cool the helium that has not been completely purified. The above-mentioned method of condensation separation avoids the use of a molecular sieve bed, which is relatively convenient; the first loop is set to recover the cold energy of the pure helium, which is relatively energy-saving. A regulating valve is provided in the system, and during operation, the opening degree of the first regulating valve can be adjusted according to the impurity content in the first loop to reduce the liquid nitrogen consumption; the temperature of the helium in the first unit can be controlled by adjusting the second regulating valve, which is relatively convenient to use.

Description

Technical Field

[0001] The present invention relates to the field of helium purification in nuclear reactors, and particularly to a helium purification system and an operation method thereof. Background Art

[0002] In a nuclear reactor, helium can be used as a coolant in the primary loop to transfer the heat of the reactor core. During the operation of the nuclear reactor, impurities from various pollution sources will gradually mix into the helium, such as hydrogen, carbon monoxide, nitrogen, methane, and isotopes of radioactive nuclides Kr and Xe. The above impurities will have an adverse impact on the operation of the nuclear reactor. Therefore, a nuclear reactor usually needs to be equipped with a helium purification system.

[0003] The helium purification system of the High Temperature Gas-cooled Reactor Demonstration Project HTR-PM mainly includes three purification processes, and the three purification processes respectively achieve the purification of helium through a copper oxide bed and an electric heater, a cooler and a molecular sieve bed, and a low-temperature adsorber (cryogenic activated carbon bed). Among them: the copper peroxide bed and the electric heater are used to convert the impurity hydrogen and carbon monoxide in the helium into water and carbon dioxide respectively; the cooler and the molecular sieve bed are used to remove the impurity water and carbon dioxide in the helium containing impurity water and carbon dioxide after primary cooling, secondary cooling, gas-water separation, and adsorption by the molecular sieve bed; the low-temperature adsorber (cryogenic activated carbon bed) is used to remove the remaining impurities in the helium.

[0004] After the above helium purification system operates for a period of time, the molecular sieve bed will reach saturation. Therefore, the molecular sieve bed needs to be periodically isolated from the system, and a regeneration system is used to regenerate the adsorption capacity of the molecular sieve bed. However, the regeneration process of the molecular sieve bed has the following problems: the regeneration process is complex and requires a large number of equipment; the regeneration process generally takes dozens of hours and is time-consuming; the regeneration of the molecular sieve bed cannot completely remove the water and carbon dioxide in it, and the residual water or carbon dioxide may freeze in the downstream pipeline of the system, resulting in blockage of the downstream pipeline. Summary of the Invention

[0005] The present invention is based on the inventor's discovery and recognition of the following facts and problems: in the existing helium purification system, a cooler and a molecular sieve bed are generally used to remove the impurity water and carbon dioxide in the helium. The molecular sieve bed needs to be regenerated regularly, and the regeneration process of the molecular sieve bed is complex, time-consuming, and has a poor regeneration effect.

[0006] The present invention aims to solve at least one of the technical problems in the related art to a certain extent.

[0007] To this end, an embodiment of the present invention provides a helium purification system. The helium purification system removes water and carbon dioxide in the helium by means of condensation separation, does not need to use a molecular sieve bed, and is more convenient to use.

[0008] The embodiments of the present invention also propose two operation methods for a helium purification system.

[0009] The helium purification system according to the embodiments of the present invention includes a first unit, a second unit, a third unit, a fourth unit, and a first pipeline. The first unit is adapted to input helium to be purified, and convert hydrogen and carbon monoxide in the helium to be purified into water vapor and carbon dioxide respectively, and then output first helium.

[0010] The second unit is connected to the first unit. The second unit includes a first heat exchanger and a first container. The first heat exchanger is adapted to cool the first helium to a first temperature range. The first container is connected to the first heat exchanger and is adapted to receive the liquid water or ice condensed from the first helium. The second unit outputs second helium.

[0011] The third unit is connected to the second unit. The third unit includes a second heat exchanger and a second container. The second heat exchanger is adapted to cool the second helium to a second temperature range. The second container is connected to the second heat exchanger and is adapted to receive the liquid carbon dioxide condensed from the second helium. The third unit outputs third helium.

[0012] The fourth unit is connected to the third unit, and at least part of the third helium enters the fourth unit. The fourth unit is adapted to remove the remaining impurities in the third helium and output pure helium.

[0013] The first pipeline is connected to the fourth unit and is adapted to receive the pure helium. The first pipeline is sequentially connected to the second heat exchanger and the first heat exchanger, and the pure helium in the first pipeline is adapted to cool the second helium and the first helium.

[0014] In the helium purification system according to the embodiments of the present invention, the second unit includes a first heat exchanger and a first container. Helium containing water vapor and carbon dioxide can be cooled to a first temperature range in the first heat exchanger. In the first temperature range, the water vapor in the helium is converted into liquid water or ice. The first container is connected to the first heat exchanger to collect the liquid water or ice condensed from the helium, and finally the removal of water vapor in the helium is realized.

[0015] The third unit includes a second heat exchanger and a second container. Helium containing carbon dioxide can be cooled to a second temperature range in the second heat exchanger. In the second temperature range, the carbon dioxide in the helium is converted into liquid. The second container is connected to the second heat exchanger to collect the liquid carbon dioxide condensed from the helium, and finally the removal of water vapor and carbon dioxide in the helium is realized.

[0016] By installing the second and third units to remove water vapor and carbon dioxide from the helium, the molecular sieve bed is no longer required, eliminating the need for periodic regeneration, a complex and time-consuming process. The first loop allows the use of pure helium to cool unpurified helium, saving energy.

[0017] In some embodiments, the helium purification system includes a second pipeline connected to the third helium outlet and the pure helium outlet of the first heat exchanger, and a first regulating valve is provided on the second pipeline.

[0018] In some embodiments, the fourth unit includes a liquid nitrogen tank and an activated carbon bed, wherein the activated carbon bed is disposed in the liquid nitrogen tank, the liquid nitrogen tank is suitable for cooling the third helium entering the activated carbon bed, and the activated carbon bed is suitable for adsorbing the remaining impurities.

[0019] In some embodiments, the helium purification system includes a third pipeline, which is connected to the liquid nitrogen tank and is suitable for receiving the low-temperature nitrogen generated in the liquid nitrogen tank. The third pipeline is sequentially connected to the second heat exchanger and the first heat exchanger, and the low-temperature nitrogen is suitable for cooling the second helium and the first helium.

[0020] In some embodiments, the helium purification system includes a fourth pipeline connected to the cryogenic nitrogen outlet side of the liquid nitrogen tank and the cryogenic nitrogen inlet side of the first heat exchanger, and a second regulating valve is provided on the fourth pipeline.

[0021] In some embodiments, the first temperature range is -10 to -2 degrees Celsius.

[0022] In some embodiments, the second temperature range is -80 to -70 degrees Celsius.

[0023] In some embodiments, the first heat exchanger and the second heat exchanger are both shell and tube heat exchangers, and heat exchange coils are provided on the periphery of the first heat exchanger and the second heat exchanger, and the heat exchange coils are suitable for circulating the low-temperature nitrogen.

[0024] One of the operating methods of the helium purification system according to an embodiment of the present invention is:

[0025] When the impurity concentration of the helium in the primary circuit is lower than a set value, the first regulating valve is adjusted to a set opening, and a portion of the third helium gas is merged into the pure helium gas through the second pipeline. By adjusting the opening of the first regulating valve to allow a portion of the third helium gas to be directly merged into the pure helium gas, the fourth unit's processing capacity can be reduced, resulting in greater energy savings.

[0026] The second operating method of the helium purification system according to the embodiment of the present invention is:

[0027] When the temperature of the first helium gas in the first heat exchanger is higher than the set temperature, increase the opening degree of the second regulating valve to increase the flow rate of the low-temperature nitrogen gas flowing through the first heat exchanger. Increasing the second regulating valve allows more low-temperature nitrogen gas to directly flow into the first heat exchanger, facilitating the regulation of the temperature of the first helium gas in the first heat exchanger. Description of the Drawings

[0028] Figure 1 It is a schematic diagram of the helium purification system according to an embodiment of the present invention.

[0029] In the figure:

[0030] 100, the first unit; 11, the filter; 12, the electric heater; 13, the copper oxide bed;

[0031] 200, the second unit; 21, the nitrogen heat exchanger; 22, the helium-nitrogen heat exchanger; 23, the first heat exchanger; 24, the first outlet;

[0032] 300, the third unit; 31, the second heat exchanger; 32, the second outlet;

[0033] 400, the fourth unit; 41, the liquid nitrogen tank; 42, the activated carbon bed;

[0034] 5, the first pipeline; 6, the second pipeline; 61, the first regulating valve; 7, the third pipeline; 8, the fourth pipeline; 81, the second regulating valve. Detailed Embodiments

[0035] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0036] As Figure 1 shown, the helium purification system according to an embodiment of the present invention includes a first unit 100, a second unit 200, a third unit 300, a fourth unit 400, and a first pipeline 5. The first unit 100 is adapted to input the helium gas to be purified and output the first helium gas after converting hydrogen and carbon monoxide in the helium gas to be purified into water vapor and carbon dioxide respectively.

[0037] As Figure 1 shown, the first unit 100 may include a filter 11, an electric heater 12, and a copper oxide bed 13 connected in sequence. The filter 11 can filter out particulate impurities in the helium gas to be purified, playing a role in protecting downstream equipment. The filtering method adopted by the filter 11 can be activated carbon filtration, sintered stainless steel filter element filtration, etc.

[0038] The helium gas filtered by the filter 11 enters the electric heater 12 for heating. The electric heater 12 is used to heat the helium gas to the temperature required for subsequent reactions. The heated helium gas enters the copper oxide bed 13, which contains a copper-based catalyst. Under the action of the copper-based catalyst, hydrogen and carbon monoxide in the helium gas are converted into water vapor and carbon dioxide.

[0039] As Figure 1 shown, the second unit 200 is connected to the first unit 100. The second unit 200 includes a first heat exchanger 23 and a first container. The first heat exchanger 23 is adapted to cool the first helium gas to a first temperature range. The first container is connected to the first heat exchanger 23 and is adapted to receive liquid water or ice condensed from the first helium gas. The second unit 200 outputs a second helium gas.

[0040] The first heat exchanger 23 can be a shell-and-tube heat exchanger. The first helium gas can flow through the shell side of the first heat exchanger 23, and a low-temperature fluid can flow through the tube side. The low-temperature fluid exchanges heat with the first helium gas and cools the first helium gas to the first temperature range. In the first temperature range, the water vapor in the first helium gas is converted into water or ice. The first container can be connected to the shell side of the first heat exchanger 23, and the water or ice condensed from the first helium gas flows into the first container. A first outlet 24 can be provided on the first container, and the first outlet 24 is used to periodically discharge the water or ice in the first container.

[0041] As Figure 1 shown, the third unit 300 is connected to the second unit 200. The third unit 300 includes a second heat exchanger 31 and a second container. The second heat exchanger 31 is adapted to cool the second helium gas to a second temperature range. The second container is connected to the second heat exchanger 31 and is adapted to receive liquid carbon dioxide condensed from the second helium gas. The third unit 300 outputs a third helium gas.

[0042] The second heat exchanger 31 can also be a shell-and-tube heat exchanger. The second helium gas can flow through the shell side of the second heat exchanger 31, and a low-temperature fluid can flow through the tube side. The low-temperature fluid exchanges heat with the second helium gas and cools the second helium gas to the second temperature range. In the second temperature range, the carbon dioxide in the second helium gas becomes liquid. The second container can be connected to the shell side of the second heat exchanger 31, and the liquid carbon dioxide condensed from the second helium gas flows into the second container. A second outlet 32 can be provided on the second container, and the second outlet 32 is used to periodically discharge the water or ice in the second container.

[0043] As Figure 1As shown, the fourth unit 400 is connected to the third unit 300, and at least part of the third helium enters the fourth unit 400. The fourth unit 400 is adapted to remove the remaining impurities in the third helium and output pure helium. The fourth unit 400 is used to remove the remaining impurities in the third helium so that the helium impurity content in the primary loop is within the permitted content range.

[0044] As Figure 1 shown, the first pipeline 5 is connected to the fourth unit 400 and is adapted to receive pure helium. The first pipeline 5 is successively connected to the second heat exchanger 31 and the first heat exchanger 23, and the pure helium in the first pipeline 5 is adapted to cool the second helium and the first helium.

[0045] The purpose of setting the first pipeline 5 to transport the pure helium back to the second heat exchanger 31 and the first heat exchanger 23 is to recover the cold energy in the pure helium and save energy. At the same time, the temperature of the pure helium after releasing the cold energy is closer to the temperature of the helium in the primary loop, making the operation of the primary loop more stable.

[0046] In the helium purification system according to the embodiment of the present invention, the second unit 200 includes the first heat exchanger 23 and the first container. The helium containing water vapor and carbon dioxide can be cooled to the first temperature range in the first heat exchanger 23. In the first temperature range, the water vapor in the helium is converted into liquid water or ice. The first container is connected to the first heat exchanger 23 to collect the liquid water or ice condensed from the helium, and finally the removal of the water vapor in the helium is realized.

[0047] The third unit 300 includes the second heat exchanger 31 and the second container. The helium containing carbon dioxide can be cooled to the second temperature range in the second heat exchanger 31. In the second temperature range, the carbon dioxide in the helium is converted into liquid. The second container is connected to the second heat exchanger 31 to collect the liquid carbon dioxide condensed from the helium, and finally the removal of the water vapor and carbon dioxide in the helium is realized.

[0048] By setting the second unit 200 and the third unit 300 to remove the water vapor and carbon dioxide in the helium, there is no need to use a molecular sieve bed, which solves the problems that the molecular sieve bed needs to be regenerated regularly, and the regeneration process is complex and time-consuming. Setting the first loop can cool the unpurified helium with pure helium, saving energy.

[0049] In some embodiments, as Figure 1 shown, the helium purification system includes a second pipeline 6. The second pipeline 6 is connected to the third helium outlet side and the pure helium outlet side of the first heat exchanger 23, and a first regulating valve 61 is provided on the second pipeline 6.

[0050] Since the helium purification system operates in series in the primary loop, when the detection device detects that the total helium impurity content in the primary loop is much lower than the set content, the opening degree of the first regulating valve 61 can be controlled to allow part of the third helium to enter the fourth unit 400 for purification, and the remaining helium directly bypasses the fourth unit 400 and continues to circulate in the primary loop. The purpose of this setting is to reduce the processing amount of helium by the fourth unit 400. For example, when the fourth unit 400 cools the third helium with liquid nitrogen to remove the remaining impurities therein, the above setting can effectively reduce the evaporation amount of liquid nitrogen, thereby reducing the operating cost of the system.

[0051] In some embodiments, as Figure 1 shown, the fourth unit 400 includes a liquid nitrogen tank 41 and an activated carbon bed 42. The activated carbon bed 42 is arranged in the liquid nitrogen tank 41. The liquid nitrogen tank 41 is adapted to cool the third helium entering the activated carbon bed 42, and the activated carbon bed 42 is adapted to adsorb the remaining impurities. Arranging the liquid nitrogen tank 41 can further cool the third helium, and the activated carbon bed 42 has a better adsorption effect on the impurities in the third helium in a low-temperature environment.

[0052] In some embodiments, as Figure 1 shown, the helium purification system includes a third pipeline 7. The third pipeline 7 is connected to the liquid nitrogen tank 41 and is adapted to receive the low-temperature nitrogen generated in the liquid nitrogen tank 41. The third pipeline 7 is sequentially connected to the second heat exchanger 31 and the first heat exchanger 23, and the low-temperature nitrogen is adapted to cool the second helium and the first helium. Arranging the third pipeline 7 can cool the second helium and the first helium with the low-temperature nitrogen, thereby achieving the purpose of recovering the cold energy in the low-temperature nitrogen and saving energy. The helium flowing out of the third pipeline 7 can be collected for standby or discharged through the exhaust pipeline.

[0053] In some embodiments, as Figure 1 shown, the helium purification system includes a fourth pipeline 8. The fourth pipeline 8 is connected to the low-temperature nitrogen outlet side of the liquid nitrogen tank 41 and the low-temperature nitrogen inlet side of the first heat exchanger 23, and a second regulating valve 81 is provided on the fourth pipeline 8.

[0054] The purpose of arranging the fourth pipeline 8 is to adjust the flow rate of the low-temperature nitrogen flowing through the first heat exchanger 23 and the second heat exchanger 31. For example, when the temperature of the first helium in the first heat exchanger 23 is higher than the first temperature range, the opening degree of the second regulating valve 81 is increased, so that more low-temperature nitrogen bypasses the second heat exchanger 31 and directly flows to the first heat exchanger 23, and the cooling effect of the low-temperature nitrogen on the first helium is enhanced, so that the temperature of the first helium is stabilized within the first temperature range.

[0055] In some embodiments, the first temperature range is -10 to -2 degrees Celsius. Within this temperature range, the water vapor in the first helium can be effectively converted into water or ice, and it is more energy-efficient at the same time.

[0056] In some embodiments, the second temperature range is from -80 to -70 degrees Celsius. Within this temperature range, carbon dioxide in the second helium can be effectively converted into liquid state while being relatively energy-efficient.

[0057] In some embodiments, as Figure 1 shown, both the first heat exchanger 23 and the second heat exchanger 31 are shell-and-tube heat exchangers, and heat exchange coils are provided on the outer peripheries of the first heat exchanger 23 and the second heat exchanger 31. The heat exchange coils are adapted for low-temperature nitrogen to flow through. The first helium and the second helium respectively flow through the shell sides of the first heat exchanger 23 and the second heat exchanger 31, the pure helium flows through the tube side, and the low-temperature nitrogen flows through the heat exchange coils and exchanges heat with the helium to be purified. Under the dual cooling effects of the low-temperature nitrogen and the pure helium, the first helium and the second helium can respectively reach the first temperature range and the second temperature range, and the layout structure of the above shell-and-tube heat exchangers is relatively compact, saving space.

[0058] In some embodiments, as Figure 1 shown, the first unit 100 further includes a nitrogen heat exchanger 21 and a helium-nitrogen heat exchanger 22. The nitrogen heat exchanger 21 is arranged behind the copper oxide bed 13 and is used for exchanging heat between the pure helium discharged from the first heat exchanger 23 and the first helium discharged from the copper oxide bed 13, playing a role in precooling the first helium. Specifically, the temperature of the first helium is cooled to 50 - 80 degrees Celsius. At the same time, in the nitrogen heat exchanger 21, the pure helium is heated to a temperature close to that of the helium in the first circuit.

[0059] The helium-nitrogen heat exchanger 22 is arranged between the nitrogen heat exchanger 21 and the first heat exchanger 23 and is used for exchanging heat between the first helium discharged from the nitrogen heat exchanger 21 and the low-temperature nitrogen discharged from the first heat exchanger 23. The helium-nitrogen heat exchanger 22 is provided to further precool the first helium, and at the same time, further recover the cold energy in the low-temperature nitrogen, reducing energy consumption. The low-temperature nitrogen discharged from the helium-nitrogen heat exchanger 22 can be collected for standby or discharged through a pipeline.

[0060] The operation methods of two helium purification systems according to embodiments of the present invention are described below.

[0061] One of the operation methods of the helium purification system according to embodiments of the present invention is:

[0062] When the impurity concentration of the helium in the first circuit is lower than the set value, adjust the first regulating valve 61 to the set opening degree, and part of the third helium flows into the pure helium through the second pipeline 6. By adjusting the opening degree of the first regulating valve 61 to directly make part of the third helium flow into the pure helium, the processing amount of the helium by the fourth unit 400 can be reduced, which is relatively energy-efficient. For example, when the fourth unit 400 includes a liquid nitrogen tank 41, the above setting can effectively reduce the evaporation of liquid nitrogen and reduce the consumption of liquid nitrogen.

[0063] Another operation method of the helium purification system according to the embodiment of the present invention is as follows:

[0064] When the temperature of the first helium gas in the first heat exchanger 23 is higher than the set temperature, increase the opening degree of the second regulating valve 81 to increase the flow rate of the low-temperature nitrogen gas flowing through the first heat exchanger 23. Increasing the second regulating valve 81 enables more low-temperature nitrogen gas to directly flow into the first heat exchanger 23, realizing the adjustment of the temperature of the first helium gas in the first heat exchanger 23, which is relatively convenient.

[0065] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0066] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0067] In the present invention, unless otherwise clearly specified and defined, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is less than that of the second feature.

[0069] In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0070] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A helium purification system, characterized in that, Comprising: A first unit adapted to input helium to be purified, and convert hydrogen and carbon monoxide in the helium to be purified into water vapor and carbon dioxide respectively, and then output first helium; A second unit connected to the first unit. The second unit includes a first heat exchanger and a first container. The first heat exchanger is adapted to cool the first helium to a first temperature range. The first container is connected to the first heat exchanger and is adapted to receive liquid water or ice condensed from the first helium. The second unit outputs second helium; A third unit connected to the second unit. The third unit includes a second heat exchanger and a second container. The second heat exchanger is adapted to cool the second helium to a second temperature range. The second container is connected to the second heat exchanger and is adapted to receive liquid carbon dioxide condensed from the second helium. The third unit outputs third helium; A fourth unit connected to the third unit, and at least part of the third helium enters the fourth unit. The fourth unit is adapted to remove remaining impurities in the third helium and output purified helium; A first pipeline connected to the fourth unit and adapted to receive the purified helium. The first pipeline is sequentially connected to the second heat exchanger and the first heat exchanger, and the purified helium in the first pipeline is adapted to cool the second helium and the first helium; The first unit includes a copper oxide bed, a nitrogen heat exchanger, and a helium-nitrogen heat exchanger. The nitrogen heat exchanger is arranged behind the copper oxide bed and is used for heat exchange between the purified helium discharged from the first heat exchanger and the first helium discharged from the copper oxide bed. The helium-nitrogen heat exchanger is arranged between the nitrogen heat exchanger and the first heat exchanger and is used for heat exchange between the first helium discharged from the nitrogen heat exchanger and the low-temperature nitrogen discharged from the first heat exchanger; The fourth unit includes a liquid nitrogen tank and an activated carbon bed, and includes a third pipeline connected to the liquid nitrogen tank and adapted to receive the low-temperature nitrogen generated in the liquid nitrogen tank. The third pipeline is sequentially connected to the second heat exchanger and the first heat exchanger, and the low-temperature nitrogen is adapted to cool the second helium and the first helium; Including a second pipeline connected to the outlet side of the third helium and the outlet side of the purified helium of the first heat exchanger, and a first regulating valve is provided on the second pipeline.

2. The helium purification system according to claim 1, characterized in that, The activated carbon bed is arranged in the liquid nitrogen tank. The liquid nitrogen tank is adapted to cool the third helium entering the activated carbon bed, and the activated carbon bed is adapted to adsorb the remaining impurities.

3. The helium purification system according to claim 2, wherein, Including a fourth pipeline connected to the outlet side of the low-temperature nitrogen of the liquid nitrogen tank and the inlet side of the low-temperature nitrogen of the first heat exchanger, and a second regulating valve is provided on the fourth pipeline.

4. The helium purification system according to claim 1, characterized in that, The first temperature range is -10 to -2 degrees Celsius.

5. The helium purification system according to claim 1, wherein, The second temperature range is -80 to -70 degrees Celsius.

6. The helium purification system according to claim 2, wherein Both the first heat exchanger and the second heat exchanger are shell-and-tube heat exchangers, and heat exchange coils are provided on the outer peripheries of both the first heat exchanger and the second heat exchanger, and the heat exchange coils are adapted to allow the low-temperature nitrogen gas to flow therethrough.

7. A method for operating a helium purification system, characterized in that, Including the helium purification system according to any one of claims 2-6, when the impurity concentration of the helium gas in the primary circuit is lower than the set value, the first regulating valve is adjusted to the set opening degree, and part of the third helium gas is introduced into the pure helium gas through the second pipeline.

8. A method for operating a helium purification system, characterized in that, Including the helium purification system according to claim 3, when the temperature of the first helium gas in the first heat exchanger is higher than the set temperature, the opening degree of the second regulating valve is increased to increase the flow rate of the low-temperature nitrogen gas flowing through the first heat exchanger.

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