High-flow high-temperature high-pressure purification device and purification method for liquid xenon detector

Abstract

The invention provides a high-flow high-temperature high-pressure purification device and method for a liquid xenon detector. The purification device comprises a first gear pump, a first heat exchanger, a second heat exchanger, a high-temperature purifier, a liquefaction module, a third heat exchanger and a second gear pump, and the first gear pump extracts a first liquid xenon medium from the liquid xenon detector and pressurizes the first liquid xenon medium; the pressurized first liquid xenon medium enters a first heat exchanger and a second heat exchanger for heat exchange, and the output first gas xenon medium enters a high-temperature purifier for purification treatment and then becomes a second gas xenon medium to enter the hot side of the second heat exchanger; the second gas xenon medium enters the liquefaction module to be cooled and liquefied, then enters the hot side of the first heat exchanger to be subjected to heat exchange to form a second liquid xenon medium, then enters the hot side of the third heat exchanger to be cooled, and finally returns to the liquid xenon detector after being subjected to pressure regulation through a tenth pipeline, a second gear pump and an eleventh pipeline. The device disclosed by the invention is small in space requirement and large in circulating flow, and can obtain a better purification effect on a high-purity target substance of a rare event particle detector.

Description

Technical Field

[0001] The present invention relates to the technical field of purification of high-purity target materials for rare event detectors, and in particular to a high-flow, high-temperature, and high-pressure purification device and a purification method for a liquid xenon detector. Background Art

[0002] The signals expected by rare high-energy physics experiments such as dark matter detection and neutrinoless double-beta decay detection are very rare and weak. The target material of the detector needs to be of extremely high purity. Noble gases such as xenon and argon are often used as target materials for such detectors. When the target particle collides with the target material, photons and free electrons are emitted. The free electrons drift under the action of the electric field and emit secondary light. Electronegative elements such as C, N, O, and H in the target material will absorb the free electrons, thereby deteriorating the performance of the detector. Therefore, the content of electronegative elements in the target material needs to be strictly controlled, and the O element needs to be controlled within 10 -9 mol / mol or lower levels.

[0003] Currently, high-purity xenon and argon used in conventional particle detectors utilize purifiers to remove electronegative elements. Filler materials used for purification are primarily zirconium-aluminum alloys, zirconium-vanadium-iron alloys, and zirconium-titanium alloys. Operating at approximately 400°C, the electronegative elements in rare gases like xenon and argon react with the filler to form solid compounds, thereby purifying the gases. Other purification devices, such as the one proposed in invention patent ZL202210948816.1, require higher operating temperatures, exceeding 600°C. However, current mainstream rare event detectors require low temperatures to maintain the target density by maintaining the argon and xenon noble gases in a liquid state. This purification process involves heating the liquid argon or xenon to vaporize it, purifying it at high temperatures, and then cooling it to liquefy it. This involves two phase transitions at relatively low temperatures, resulting in low cooling efficiency and high energy consumption. Furthermore, the gas diaphragm pumps used to circulate the gaseous target can only pressurize ambient-temperature gas, limiting circulation flow, pressurization capacity, and operating life. This restricts the speed of target purification and has become a bottleneck in the scale-up of rare event detectors.

[0004] As rare event detectors scale up, the purity requirements for target substances are becoming increasingly stringent, placing higher demands on purification efficiency, requiring faster purification speeds and better results. Furthermore, as experimental scale expands, experimental space becomes increasingly limited, leading to the need for purifiers that improve purification performance without increasing size. Summary of the Invention

[0005] In response to the above technical problems, the present invention provides a high-flow, high-temperature, and high-pressure purification device and purification method for a liquid xenon detector. A gear pump without a dynamic seal is used to pressurize and output a liquid target material. The target material is vaporized in a high-pressure state and enters a high-temperature purifier. After contacting the functional materials of the high-temperature purifier, it is purified. It is liquefied in a high-pressure state, cooled, and then decompressed and returned to the liquid xenon detector. This device not only achieves better purification effects in purifying the liquid target material, but also requires less space and can achieve high-flow circulation purification.

[0006] To achieve the above-mentioned object, the present invention provides a liquid xenon detector high-flow, high-temperature, and high-pressure purification device, the liquid xenon detector high-flow, high-temperature, and high-pressure purification device comprising: a first gear pump connected to the liquid xenon detector via a first pipeline, configured to extract a first liquid xenon medium from the liquid xenon detector and output the medium after pressurization, wherein the absolute output pressure of the first gear pump is greater than or equal to three times the absolute operating pressure of the liquid xenon detector; a first heat exchanger, wherein the first liquid xenon medium outputted from the output end of the first gear pump enters the cold side of the first heat exchanger through the second pipe for heat exchange, and the cold side of the first heat exchanger outputs the first liquid xenon medium through the third pipe; The second heat exchanger inputs the first liquid xenon medium or the first gas xenon medium formed by vaporizing the first liquid xenon medium to the cold side of the second heat exchanger through a fourth pipeline, and outputs the first gas xenon medium from the cold side of the second heat exchanger after heat exchange; A high-temperature purifier, wherein the first xenon gas medium output from the cold side of the second heat exchanger enters the high-temperature purifier through a fifth pipeline for purification, enters the hot side of the second heat exchanger through a sixth pipeline for heat exchange, and is then output; The second xenon gas medium output from the hot side of the second heat exchanger enters the liquefaction module through the seventh pipeline for cooling and liquefaction, then enters the hot side of the first heat exchanger through the eighth pipeline for heat exchange before being output, and the absolute pressure of the second xenon gas medium leaving the hot side of the second heat exchanger and the second xenon gas medium in the liquefaction module when liquefied is 0.5 MPa or higher than the absolute operating pressure of the liquid xenon detector; a third heat exchanger, wherein the second liquid xenon medium output from the hot side of the first heat exchanger enters the hot side of the third heat exchanger through a ninth pipe for heat exchange and is cooled to a temperature below the rated operating temperature of the liquid xenon detector; The second gear pump, the second liquid xenon medium output from the hot side of the third heat exchanger enters the second gear pump through the tenth pipeline, and returns to the liquid xenon detector through the eleventh pipeline, and the second gear pump can operate in a boost state or a depressurization state.

[0007] As an optional technical solution, the liquefaction module includes a primary liquefier and a liquefaction heat exchanger and a first pressure sensor arranged in the primary liquefier. The liquefaction heat exchanger is used to exchange heat with a second gas xenon medium entering the primary liquefier to liquefy the second gas xenon medium. The first pressure sensor is used to measure the actual working pressure in the primary liquefier.

[0008] As an optional technical solution, it also includes the thermal management system, which includes a refrigerant storage tank, a low-temperature xenon coil, a first refrigerator and a second refrigerator. The low-temperature xenon coil is arranged in the refrigerant storage tank, and the input end of the low-temperature xenon coil is connected to the cold side of the first heat exchanger through the third pipe, and the output end of the low-temperature xenon coil is connected to the cold side of the second heat exchanger through the fourth pipe. The first refrigerator conveys the first refrigerant to the refrigerant storage tank through the first refrigerant pipe, and the first refrigerant that completes the heat exchange returns to the first refrigerator through the second refrigerant pipe; the second refrigerator is connected between the refrigerant storage tank and the primary liquefier, and the second refrigerator outputs the first refrigerant to the liquefied heat exchanger through the fourth refrigerant pipe, and the first refrigerant that completes the heat exchange returns to the second refrigerator through the fifth refrigerant pipe.

[0009] As an optional technical solution, the second refrigerator includes a compressor, a water-cooled heat exchanger, a regenerative heat exchanger, a condensing heat exchanger, a refrigerant circulation pump and a first throttle valve. The first refrigerant in the refrigerant storage tank enters the cold side of the condensing heat exchanger through a third refrigerant pipe and the refrigerant circulation pump, and after completing the heat exchange, flows back to the refrigerant storage tank through a fourth refrigerant pipe; after being compressed to a high temperature and high pressure state by the compressor, the first refrigerant enters the water-cooled heat exchanger through the first refrigerant pipe for cooling, and then enters the regenerative heat exchanger through the second refrigerant pipe for further cooling, and then enters the hot side of the condensing heat exchanger through the third refrigerant pipe; the first refrigerant entering the hot side of the condensing heat exchanger is condensed and liquefied and throttled by the first throttle valve for cooling, enters the liquefied heat exchanger and exchanges heat with the second gas xenon medium in the primary liquefier, and then returns to the cold side of the regenerative heat exchanger through the fifth refrigerant pipe. The first refrigerant entering the cold side of the regenerative heat exchanger returns to the compressor for recycling after heat exchange through the sixth refrigerant pipe.

[0010] As an optional technical solution, the pressure drop caused by the flow resistance of the liquid xenon medium in the first pipeline, the second pipeline, the third pipeline, and the eighth pipeline at the rated mass flow rate should be less than 10 kPa; the pressure drop caused by the flow resistance of the gaseous xenon medium in the fourth pipeline, the fifth pipeline, the sixth pipeline, and the seventh pipeline at the rated mass flow rate should be less than 10 kPa; the sum of the pressure drops caused by the flow resistance of the liquid xenon medium in the ninth pipeline and the tenth pipeline at the rated mass flow rate should be within the range of 50% to 100% of the difference between the rated working pressures of the primary liquefier and the liquid xenon detector; the pressure drop caused by the flow resistance of the liquid xenon medium in the eleventh pipeline at the rated mass flow rate should be within the range of 25% to 100% of the difference between the rated working pressures of the primary liquefier and the liquid xenon detector.

[0011] As an optional technical solution, a third refrigerator is also included. The rated output temperature of the refrigerant of the third refrigerator is lower than the rated operating temperature of the liquid xenon detector. The second refrigerant output by the third refrigerator enters the cold side of the third heat exchanger through the fifth refrigerant pipe, and returns to the third refrigerator through the sixth refrigerant pipe after completing the heat exchange.

[0012] As an optional technical solution, a first valve is provided on the first pipeline, and a second valve is provided on the eleventh pipeline; all heat exchangers and pipelines in contact with the liquid xenon medium and the gas xenon medium are evacuated to a pressure of 10 - 4 When the pressure in all heat exchangers and pipelines in contact with the liquid xenon medium and the gaseous xenon medium reaches the pressure at the input end of the first gear pump, the first refrigerator is started; then the third refrigerator is started, and when the temperature in the brine tank reaches the rated operating temperature of the first brine, the second refrigerator is started; subsequently, when the first refrigerator, the second refrigerator, and the third refrigerator have all cooled to their respective rated operating temperatures, the first gear pump is started at a low speed, and after stabilization, the speed of the drive motor of the first gear pump is gradually increased; until the gaseous xenon pressure in the primary liquefier reaches the rated operating pressure of the primary liquefier, the drive motor of the second gear pump is started and adjusted to an appropriate speed according to the actual pressure of the primary liquefier, and then the speed of the drive motor of the first gear pump is slowly increased to reach the rated speed, and the speed of the drive motor of the second gear pump is increased accordingly.

[0013] As an optional technical solution, it also includes a fourth refrigerator, which transports a third refrigerant to the liquefied heat exchanger through a seventh refrigerant pipe. The third refrigerant that completes the heat exchange returns to the fourth refrigerator through an eighth refrigerant pipe. The rated output temperature of the third refrigerant of the fourth refrigerator is a first temperature, which is 5~10°C lower than the liquefaction temperature or boiling temperature of the xenon gas medium at the first pressure, wherein the first pressure is the rated working pressure of the primary liquefier.

[0014] As an optional technical solution, the target substance xenon entering the eighth pipe is in liquid, gaseous or gas-liquid mixture.

[0015] The present invention further provides a high-flow, high-temperature, and high-pressure liquid xenon detector purification method using the high-flow, high-temperature, and high-pressure liquid xenon detector purification device described above, the high-flow, high-temperature, and high-pressure liquid xenon detector purification method comprising: Step S1, the first gear pump extracts the first liquid xenon medium from the liquid xenon detector through the first pipeline and outputs the liquid xenon medium after pressurization; Step S2: the first liquid xenon medium outputted from the output end of the first gear pump enters the cold side of the first heat exchanger through the second pipe for heat exchange and is outputted through the third pipe; Step S3: Inputting the first liquid xenon medium or the first gas xenon medium vaporized from the first liquid xenon medium into the cold side of the second heat exchanger through the fourth pipe, and outputting the first gas xenon medium from the cold side of the second heat exchanger after heat exchange; Step S4: the first xenon gas medium output from the cold side of the second heat exchanger enters the high-temperature purifier through the fifth pipeline for purification, and then enters the hot side of the second heat exchanger through the sixth pipeline for heat exchange; Step S5: the second xenon gas medium output from the hot side of the second heat exchanger enters the liquefaction module through the seventh pipeline for cooling and liquefaction, and then enters the hot side of the first heat exchanger through the eighth pipeline for heat exchange; Step S6: the second liquid xenon medium output from the hot side of the first heat exchanger enters the hot side of the third heat exchanger through a ninth pipe for heat exchange and is cooled to a temperature below the rated operating temperature of the liquid xenon detector; In step S7, the second liquid xenon medium outputted from the hot side of the third heat exchanger enters the second gear pump through the tenth pipeline and returns to the liquid xenon detector through the eleventh pipeline.

[0016] Compared with the prior art, the liquid xenon detector high-flow, high-temperature, and high-pressure purification device and purification method of the present invention have the following beneficial effects: (1) The density of liquid target material (liquid xenon) is tens to hundreds of times that of gaseous target material (gas xenon). Gear pumps have a good pressurizing effect on liquid target material. Compared with gas diaphragm pumps, they can obtain very high mass flow and output pressure, have small space requirements, and have a long service life.

[0017] (2) The present invention utilizes a gear pump to increase the pressure of the liquid target material (liquid xenon), thereby increasing the partial pressure of electronegative impurity elements such as H, O, N, and C in the gaseous target material entering the high-temperature purifier, which is beneficial for chemical reactions with the functional materials in the high-temperature purifier or for the functional materials to adsorb impurity elements, thereby achieving better purification effects.

[0018] (3) The mass flow rate of target material circulation increases, the target material has more contacts with the high-temperature purifier per unit time, and the average residence time of electronegative impurity elements such as H, O, N, and C in the liquid xenon detector is shortened, which is beneficial to reducing the total content of electronegative impurities in the target material in the liquid xenon detector. The purity of the liquid target material also tends to be close, and better detector performance can be obtained.

[0019] (4) During the purification process, the working pressure of the target substance is significantly higher than the working pressure of the detector, and the boiling point or condensation point is significantly reduced. It can be liquefied using a refrigeration system with a higher rated output temperature, which improves the cooling efficiency, reduces the requirements of the circulating purification system for the output temperature and output power of the refrigeration equipment, and improves the feasibility of large-flow circulating purification.

[0020] (5) Combine the heating required for vaporization of high-pressure liquid target material with the low-temperature condensation required by the refrigerator, select appropriate refrigerants and heat exchangers, make full use of high-quality cooling capacity, improve system efficiency, and improve the feasibility of large-flow circulation purification.

[0021] (6) The gear pump has a high output pressure and is insensitive to the flow resistance of the purifier and its associated pipelines and heat exchangers. A purifier with more adsorption materials and a large adsorption surface area can be used to further improve the purification effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 FIG2 is a schematic diagram of a high-flow, high-temperature, and high-pressure purification device for a liquid xenon detector according to an embodiment of the present invention; Figure 2FIG2 is a schematic diagram of a high-flow, high-temperature, and high-pressure purification device for a liquid xenon detector according to another embodiment of the present invention; Figure 3 Schematic diagram of a high-flow, high-temperature, and high-pressure purification method for a liquid xenon detector according to an embodiment of the present invention.

[0024] The following are marked in the figure: 1. Liquid xenon detector; 2. High-temperature purifier; 3A. First gear pump; 3B. Second gear pump; 4. Coolant storage tank; 4A. Low-temperature xenon coil; 5. Primary liquefier; 5A. Liquefaction heat exchanger; 6. First refrigerator; 7. Second refrigerator; 8. Third refrigerator; 9. First pressure sensor; 11. First heat exchanger; 12. Second heat exchanger; 13. Third heat exchanger; 14. Fourth refrigerator; 21. First pipeline; 22. Second pipeline; 23. Third pipeline; 24. Fourth pipeline; 25. Fifth pipeline; 26. Sixth pipeline; 27. Seventh pipeline; 28. Eighth pipeline; 29. Ninth pipeline; 30. Tenth pipeline; 31. Eleventh pipeline; 32. First valve; 33. Second valve; 51. First coolant pipeline; 52. Second coolant pipeline; 53. Third coolant pipeline; 54. Fourth coolant pipeline; 55. Fifth coolant pipeline agent pipeline; 56, sixth refrigerant pipeline; 81, first refrigerant pipeline; 82, second refrigerant pipeline; 83, third refrigerant pipeline; 84, fourth refrigerant pipeline; 85, fifth refrigerant pipeline; 86, sixth refrigerant pipeline; 71, compressor; 72, water-cooled heat exchanger; 73, regenerative heat exchanger; 74, condensing heat exchanger; 75, refrigerant circulation pump; 76, first throttle valve; 111, cold side input end of the first heat exchanger; 112, cold side output end of the first heat exchanger; 113, hot side input end of the first heat exchanger; 114, hot side output end of the first heat exchanger; 121, cold side input end of the second heat exchanger; 122, cold side output end of the second heat exchanger; 123, hot side input end of the second heat exchanger; 124, hot side output end of the second heat exchanger; 131, hot side input end of the third heat exchanger; 132, hot side output end of the third heat exchanger. DETAILED DESCRIPTION

[0025] In order to provide a further understanding of the purpose, structure, features, and functions of the present invention, the present invention is described in detail below with reference to the embodiments.

[0026] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0027] See Figure 1 , Figure 1 A schematic diagram of a high-flow, high-temperature, and high-pressure liquid xenon detector purification device according to one embodiment of the present invention is shown. The present invention provides a high-flow, high-temperature, and high-pressure liquid xenon detector purification device comprising a first gear pump 3A, a first heat exchanger 11, a second heat exchanger 12, a high-temperature purifier 2, a liquefaction module, a third heat exchanger 13, and a second gear pump 3B. The first gear pump 3A is connected to the liquid xenon detector 1 via a first pipeline 21, i.e., the input end of the first gear pump 3A is connected to the liquid xenon detector 1. The first gear pump 3A is configured to pump a first liquid xenon medium from the liquid xenon detector 1, pressurize it, and then output it. The absolute output pressure of the first gear pump 3A is greater than or equal to three times the absolute operating pressure of the liquid xenon detector 1. The liquid xenon detector 1 is configured to detect rare event signals. The first heat exchanger 11 is connected to the output end of the first gear pump 3A via a second pipe 22. The first liquid xenon medium outputted from the output end of the first gear pump 3A enters the cold side of the first heat exchanger 11 through the second pipe 22 for heat exchange. The cold side of the first heat exchanger 11 then outputs the first liquid xenon medium via a third pipe 23.

[0028] The cold side of the second heat exchanger 12 receives a first liquid xenon medium or a first gaseous xenon medium formed by vaporizing the first liquid xenon medium via the fourth pipe 24. After heat exchange occurs on the cold side of the second heat exchanger 12, the first gaseous xenon medium is output from the cold side of the second heat exchanger 12. In other words, in one embodiment, the cold side of the first heat exchanger 11 can be directly connected to the cold side of the second heat exchanger 12 via a pipe. In this case, the third pipe 23 and the fourth pipe 24 are the same pipe or directly connected. For example, the first liquid xenon medium enters the cold side of the second heat exchanger 12. In another embodiment, other heat exchange components or systems are connected between the cold sides of the first heat exchanger 11 and the second heat exchanger 12. In this case, for example, the first gaseous xenon medium formed by vaporizing the first liquid xenon medium enters the cold side of the second heat exchanger 12. The first xenon gaseous medium output from the cold side of the second heat exchanger 12 enters the high-temperature purifier 2 through the fifth pipeline 25 for purification, becoming the second xenon gaseous medium. It then enters the hot side of the second heat exchanger 12 through the sixth pipeline 26 for heat exchange before being output. The liquefaction module is connected to the hot side of the second heat exchanger 12 via the seventh pipeline 27. The second xenon gaseous medium output from the hot side of the second heat exchanger 12 enters the liquefaction module for cooling and liquefaction through the seventh pipeline 27. It then enters the hot side of the first heat exchanger 11 through the eighth pipeline 28 for heat exchange before being output. The core function of the first heat exchanger 11 is to recover high-grade cold energy from the first liquid xenon medium. The absolute pressure of the second xenon gaseous medium leaving the hot side of the second heat exchanger 12 and within the liquefaction module during liquefaction is at least 0.5 MPa higher than the absolute operating pressure of the liquid xenon detector. Furthermore, under different operating conditions, the target xenon entering the eighth pipeline 28 may be in liquid, gaseous, or a gas-liquid mixture. The third heat exchanger 13 is connected to the hot side of the first heat exchanger 11 via a ninth pipe 29. The second liquid xenon medium output from the hot side of the first heat exchanger 11 enters the hot side of the third heat exchanger 13 for heat exchange and cooling to below the rated operating temperature of the liquid xenon detector 1. The second gear pump 3B is connected to the hot side of the third heat exchanger 13 via a tenth pipe 30. The second liquid xenon medium output from the hot side of the third heat exchanger 13 enters the second gear pump 3B via the tenth pipe 30. The second gear pump 3B can operate in either a boost or depressurization mode. The second liquid xenon medium then returns to the liquid xenon detector 1 via an eleventh pipe 31. The sum of the pressure drops caused by the flow resistance of the liquid xenon medium in the ninth pipeline 29 and the tenth pipeline 30 at the rated mass flow rate should be within the range of 50% to 100% of the difference between the rated working pressures of the primary liquefier 5 and the liquid xenon detector 1, and the difference in the resistance pressure drops of the two pipelines should not be too large. The pressure drop caused by the flow resistance of the liquid xenon medium in the eleventh pipeline 31 at the rated mass flow rate should be within the range of 25% to 100% of the difference between the rated working pressures of the primary liquefier 5 and the liquid xenon detector 1.In summary, by adjusting the direction and speed of the driving motor of the second gear pump 3B, it is possible to ensure that the second xenon gas medium in the liquefaction module operates at the rated pressure under various operating conditions, and that the second liquid xenon medium entering the liquid xenon detector 1 through the eleventh pipeline 31 has an appropriate flow rate, without momentum impact caused by excessive flow rate, while ensuring sufficient mass flow.

[0029] Specifically, because the liquid target material flow rate of the device of the present invention varies widely, the actual flow resistance of the pipelines varies. If the liquid target material flow rate is large and the sum of the resistances within the eighth pipeline 28, the ninth pipeline 29, and the tenth pipeline 30 is excessive, the speed of the drive motor of the second gear pump 3B is increased, operating in a boost mode to ensure the target material flow rate and maintain the operating pressure of the primary liquefier from the first gear pump 3A to the operating pressure within the primary liquefier within the rated range. If the liquid target material flow rate is small, the speed of the drive motor of the second gear pump 3B is reduced, or even stopped or reversed, operating in a decompression mode to ensure that the sum of the flow resistances of the eighth pipeline 28, the ninth pipeline 29, the tenth pipeline 30, and the second gear pump 3B is equal to the difference between the rated operating pressure of the liquefaction module and the rated operating pressure of the liquid xenon detector 1. Therefore, the second gear pump 3B drive motor has adjustable speed and direction, ensuring the adaptability of the device of the present invention to variable target material mass flow rates in practical applications.

[0030] For details on the connection relationship between the above components, please refer to Figure 1 The input end of the first gear cooling pump 3A is connected to the liquid xenon detector 1 via the first pipe 21. The output end of the first gear pump 3A is connected to the cold side input end 111 of the first heat exchanger 11 via the second pipe 22. The cold side output end 112 of the first heat exchanger 11 outputs the first liquid xenon medium via the third pipe 23. The cold side input end 121 of the second heat exchanger 12 inputs the first liquid xenon medium or the first gas xenon medium vaporized from the first liquid xenon medium via the fourth pipe 24. The cold side output end 122 of the second heat exchanger 12 is connected to the input end of the high temperature purifier 2 via the fifth pipe 25. The output end of the high temperature purifier 2 is connected to the cold side purifier 2 via the sixth pipe 26. The hot side pipe 26 is connected to the hot side input end 123 of the second heat exchanger 12, the hot side output end 124 of the second heat exchanger 12 is connected to the input end of the liquefaction module via the seventh pipe 27, the output end of the liquefaction module is connected to the hot side input end 113 of the first heat exchanger 11 via the eighth pipe 28, the hot side output end 114 of the first heat exchanger 11 is connected to the hot side input end 131 of the third heat exchanger 13 via the ninth pipe 29, the hot side output end 132 of the third heat exchanger 13 is connected to the input end of the second gear pump 3B via the tenth pipe 30, and the output end of the second gear pump 3B is connected to the liquid xenon detector 1 via the eleventh pipe 31.

[0031] Furthermore, the liquefaction module, for example, includes a primary liquefier 5, a liquefaction heat exchanger 5A, and a first pressure sensor 9. The liquefaction heat exchanger 5A is disposed within the primary liquefier 5. The first pressure sensor 9 measures the actual operating pressure of the second xenon gas medium within the primary liquefier 5. The liquefaction heat exchanger 5A is configured to exchange heat with the second xenon gas medium entering the primary liquefier 5 to liquefy the second xenon gas medium. The flow rate of the second gear pump 3B is adjusted based on the difference between the actual operating pressure measured by the first pressure sensor 9 and the rated operating pressure of the primary liquefier 5. Specifically, a PID control algorithm is employed to control the direction and speed of the drive motor of the second gear pump 3B. Furthermore, the liquefaction heat exchanger 5A is, for example, a coil heat exchanger or a plate heat exchanger.

[0032] The first and second gear pumps 3A and 3B, for example, both have welded pump bodies, lack dynamic seals, and enable bidirectional transmission, meeting the sealing reliability requirements for high-purity media. They are driven by precisely adjustable, bidirectional motors, such as servo motors or stepper motors, through magnetic couplings. The control system integrates temperature and pressure information at key points to determine the precise speed requirements, start and stop commands, and other parameters. In the present invention, the first gear pump 3A functions to pressurize the liquid xenon medium. The input pressure of the first gear pump 3A is lower than the output pressure of the first gear pump 3A. The second gear pump 3B can operate in either a pressurized or depressurized mode, depending on the actual liquid xenon flow rate.

[0033] When the first gear pump 3A and the second gear pump 3B are stationary, the clearances between the pump bodies and the gears, as well as between the gears themselves, are very small. This means that their flow resistance is much greater than the flow resistance of the associated pipelines. Considering that the speed of the gear pump's drive motor is precisely adjustable and that the gear pump is, in principle, a positive displacement pump, regardless of the precise proportional relationship between flow and speed due to internal leakage, the rated mass flow rate of the liquid xenon medium in the present invention is much greater than any gaseous or liquid leakage caused by the maximum pressure differential when the gear pump is stationary. Therefore, the gear pump can precisely control the flow rate while maintaining the pressure differential between the gear pump's input and output ends, thereby ensuring that the actual operating pressure of the primary liquefier 5 in the present invention is higher than the actual operating pressure of the liquid xenon detector 1.

[0034] Please continue to see Figure 1In one embodiment, the high-flow, high-temperature, and high-pressure liquid xenon detector purification device further includes a thermal management system comprising a brine tank 4, a cryogenic xenon coil 4A, a first refrigerator 6, and a second refrigerator 7. The cryogenic xenon coil 4A is disposed within the brine tank 4 and submerged below the brine liquid level. The input end of the cryogenic xenon coil 4A is connected to the cold-side output end 112 of the first heat exchanger 11 via the third pipe 23, and the output end of the cryogenic xenon coil 4A is connected to the cold-side input end 121 of the second heat exchanger 12 via the fourth pipe 24. The first refrigerator 6 delivers a relatively low-temperature first brine to the brine tank 4 via a first brine pipe 51. The first brine mixes with the existing brine in the brine tank 4 to form a relatively high-temperature brine, which is then returned to the first refrigerator 6 for recycling via the second brine pipe 52. The second refrigerator 7 is connected between the coolant storage tank 4 and the primary liquefier 5. The second refrigerator 7 outputs the throttled low-temperature first refrigerant to the liquefied heat exchanger 5A through the fourth refrigerant pipe 84. After completing the heat exchange, the first refrigerant returns to the second refrigerator 7 through the fifth refrigerant pipe 85 for recycling.

[0035] Among them, the second refrigeration machine 7 includes a compressor 71, a water-cooled heat exchanger 72, a heat recovery heat exchanger 73, a condensing heat exchanger 74, a refrigerant circulation pump 75 and a first throttle valve 76. The first refrigerant in the refrigerant storage tank 4 enters the cold side of the condensing heat exchanger 74 through the third refrigerant pipe 53 and the refrigerant circulation pump 75, and after completing the heat exchange, it flows back to the refrigerant storage tank 4 through the fourth refrigerant pipe 54 for recycling. After being compressed to a high-temperature and high-pressure state by the compressor 71, the first refrigerant enters the water-cooled heat exchanger 72 through the first refrigerant pipe 81 for cooling, then enters the regenerative heat exchanger 73 through the second refrigerant pipe 82 for further cooling, and then enters the hot side of the condensing heat exchanger 74 through the third refrigerant pipe 83; the first refrigerant entering the hot side of the condensing heat exchanger 74 is condensed and liquefied and cooled after being throttled by the first throttle valve 76, enters the liquefied heat exchanger 5A through the fourth refrigerant pipe 84 and exchanges heat with the high-pressure xenon gas in the primary liquefier 5, and then returns to the cold side of the regenerative heat exchanger 73 through the fifth refrigerant pipe 85. The first refrigerant entering the cold side of the regenerative heat exchanger 73 returns to the compressor 71 through the sixth refrigerant pipe 86 for recycling after heat exchange.

[0036] Moreover, considering the relationship between pipeline size and flow resistance, the liquid target material flow rate expected in the embodiment of the present invention is 0.25 kg / s, which is preferably low. The first pipeline 21, the second pipeline 22, the third pipeline 23 and the eighth pipeline 28 mainly transport liquid target materials, and the volume flow rate is relatively small. Pipes with smaller diameters can be used, such as 1 / 2-inch stainless steel pipes with an inner diameter of 10 mm. The pressure drop caused by the flow resistance of the liquid xenon medium in the first pipeline 21, the second pipeline 22, the third pipeline 23 and the eighth pipeline 28 at the rated mass flow rate should be less than 10 kPa. The fourth pipeline 24, the fifth pipeline 25, the sixth pipeline 26 and the seventh pipeline 27 mainly transport gaseous target materials, and the volume flow rate is relatively large. A relatively large pipeline diameter is required, such as a 1-inch hose with an inner diameter of 20 mm. The pressure drop caused by the flow resistance of the gaseous xenon medium in pipe 7 at the rated mass flow rate should be less than 10 kPa. The ninth, tenth, and eleventh pipes 29, 30, and 31 are connected to the primary liquefier 5 and the liquid xenon detector 1, both of which have higher operating pressures, and therefore require suitable fluid resistance. Calculations and experimental testing have confirmed that 1 / 4-inch stainless steel pipes, with an actual inner diameter of 4.6 mm, are suitable. Furthermore, the sum of the pressure drops caused by the flow resistance of the liquid xenon medium in pipes 9, 29, and 100% at the rated mass flow rate should be within a range of 50% to 100% of the difference between the rated operating pressures of the primary liquefier 5 and the liquid xenon detector 1, and the difference in pressure drop due to the resistance between the two pipes should not be too large. The pressure drop caused by the flow resistance of the liquid xenon medium in pipe 11 at the rated mass flow rate should be within a range of 25% to 100% of the difference between the rated operating pressures of the primary liquefier 5 and the liquid xenon detector 1. The lengths of the first, second, third, fourth, fifth, sixth, seventh, and eleventh pipes 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, and 31 also affect their fluid resistance. In the present invention, a length of 1.1 to 1.2 meters is suitable. The above figures are merely design data based on the desired medium and mass flow rates of the present invention. The core of the present invention is the control of flow resistance and its utilization to achieve the core functions of the present invention. Other pipe sizes designed based on this concept should be considered specific applications and reasonable extensions of the present invention.

[0037] The present invention also includes a third refrigerator 8, whose rated coolant output temperature is lower than the operating temperature of the liquid xenon detector 1. The second coolant output by the third refrigerator 8 enters the cold side of the third heat exchanger 13 via a fifth coolant pipe 55. After completing the heat exchange, it returns to the third refrigerator 8 via a sixth coolant pipe 56 for recycling. The second coolant can be anhydrous ethanol. The third refrigerator 8 cools the liquid target material (liquid xenon medium) to below 178K, ensuring a certain degree of subcooling, corresponding to a vapor pressure below 0.2 MPa. This means that upon entering the liquid xenon detector 1, which has the lowest operating pressure in the system or device of the present invention, the subcooled liquid (liquid xenon) does not vaporize, thus not introducing a heat load to the liquid xenon detector 1. Instead, it provides a certain amount of cooling capacity, reducing the burden on the liquid xenon detector's refrigeration system.

[0038] In this embodiment, a first valve 32 is provided on the first pipe 21, and a second valve 32 is provided on the eleventh pipe 31. All heat exchangers and pipes in contact with the liquid xenon medium and the gas xenon medium are evacuated to a pressure of 10 -4 When the pressure in all heat exchangers and pipelines in contact with the liquid xenon medium and the gaseous xenon medium reaches the input pressure of the first gear pump 3A, the first refrigerator 6 is started; then the third refrigerator 8 is started; and when the temperature in the brine tank 4 reaches the rated operating temperature of the first brine, the second refrigerator 7 is started. Subsequently, when the first refrigerator 6, the second refrigerator 7, and the third refrigerator 8 have all cooled to their respective rated operating temperatures, the first gear pump 3A is started at a low speed. After a period of stabilization, the speed of the drive motor of the first gear pump 3A is gradually increased. When the gaseous xenon pressure in the primary liquefier 5 reaches the rated operating pressure of the primary liquefier 5, the drive motor of the second gear pump 3B is started and adjusted to an appropriate speed based on the actual pressure of the primary liquefier 5. The speed of the drive motor of the first gear pump 3A is then slowly increased to reach the rated speed. During this process, the speed of the drive motor of the second gear pump 3B is also increased accordingly.

[0039] All the heat exchangers in contact with the liquid xenon medium and the gaseous xenon medium include the first heat exchanger 11, the second heat exchanger 12, and the third heat exchanger 13, and all the pipes include the first pipe 21, the second pipe 22, the third pipe 23, the fourth pipe 24, the fifth pipe 25, the sixth pipe 26, the seventh pipe 27, the eighth pipe 28, the ninth pipe 29, the tenth pipe 30, and the eleventh pipe 31.

[0040] See Figure 2 , Figure 2 The figure shows a schematic diagram of a high-flow, high-temperature, and high-pressure purification device for a liquid xenon detector according to another embodiment of the present invention. Figure 1The illustrated embodiment primarily differs in that the liquid target material is pressurized to a higher pressure, significantly increasing the liquefaction temperature and significantly simplifying the refrigeration equipment, moving from cascade refrigeration to single-stage compression refrigeration using a single refrigerant. This embodiment includes a fourth refrigerator 14, which delivers a third refrigerant to the liquefied heat exchanger 5B within the primary liquefier 5 via a seventh refrigerant pipe 57. After heat exchange, the third refrigerant returns to the fourth refrigerator 14 via an eighth refrigerant pipe 58. The third refrigerant can be ethanol or another low-melting-point, non-toxic, and non-corrosive liquid. The rated output temperature of the third refrigerant from the fourth refrigerator 14 is a first temperature, which is 5-10°C below the liquefaction or boiling temperature of the xenon gaseous medium at the first pressure. The first pressure is the rated operating pressure of the primary liquefier 5. Specifically, for example, the rated working pressure of the primary liquefier 5 is 2 MPa, and 2 MPa high-pressure xenon gas can be liquefied at 242.5K. The liquefaction process is the process with the greatest demand for refrigeration power. Considering the subcooling degree of 5K, the evaporator design temperature of the fourth refrigerator 14 is matched, for example, 233K, and the rated output temperature of the third refrigerant is 237K.

[0041] In addition, the fourth refrigerator 14 may also adopt a direct cooling mode to reduce heat exchange losses and improve the energy efficiency of the refrigeration system.

[0042] Moreover, in this embodiment, the ninth pipeline 29, the tenth pipeline 30 and the eleventh pipeline 31 are, for example, stainless steel pipes with a length of 2 m and a diameter of 4 mm to obtain appropriate flow resistance, which is conducive to the working pressure of the primary liquefier 5 being within the rated range.

[0043] See Figure 3 , Figure 3 The figure is a flow chart of a high-flow, high-temperature, and high-pressure purification method for a liquid xenon detector according to one embodiment of the present invention. The present invention further provides a high-flow, high-temperature, and high-pressure purification method for a liquid xenon detector, which is performed using the high-flow, high-temperature, and high-pressure purification apparatus for a liquid xenon detector as described above. The high-flow, high-temperature, and high-pressure purification method for a liquid xenon detector comprises: Step S1: the first gear pump extracts a first liquid xenon medium from the liquid xenon detector through the first pipeline, and outputs the liquid xenon medium after pressurization; Step S2: the first liquid xenon medium outputted from the output end of the first gear pump enters the cold side of the first heat exchanger 11 through the second pipe 22 for heat exchange and is outputted through the third pipe; In step S3, the first liquid xenon medium or the first gas xenon medium formed by vaporizing the first liquid xenon medium is inputted into the cold side of the second heat exchanger 12 through the fourth pipe 24. After heat exchange, the first gas xenon medium is outputted from the cold side of the second heat exchanger 12. Step S4: the first xenon gas medium output from the cold side of the second heat exchanger 12 enters the high-temperature purifier 2 through the fifth pipe 25 for purification, and then enters the hot side of the second heat exchanger 12 through the sixth pipe 26 for heat exchange; Step S5: The second xenon gas medium output from the hot side of the second heat exchanger 12 enters the liquefaction module through the seventh pipeline 27, is cooled and liquefied at a high pressure, and then enters the hot side of the first heat exchanger 11 through the eighth pipeline 28 for heat exchange to recover high-grade cold energy. Step S6: The second liquid xenon medium outputted from the hot side of the first heat exchanger 11 enters the hot side of the third heat exchanger 13 through the ninth pipe 29 for heat exchange and is cooled to below the rated operating temperature of the liquid xenon detector 1; In step S7, the second liquid xenon medium output from the hot side of the third heat exchanger 13 enters the second gear pump 3B through the tenth pipe 30 and returns to the liquid xenon detector 1 through the eleventh pipe 31. The second gear pump 3B determines its rotation speed based on the difference between the actual pressure of the primary liquefier 5 and the rated working pressure. In essence, it also adjusts its operation mode between the boosting state and the depressurization state based on the flow rate of the liquid target material.

[0044] The present invention is further described below with reference to specific embodiments. First embodiment

[0045] Taking the current PandaX dark matter detection experiment as an example, several high-temperature purifiers with a rated operating pressure of 1 MPa are already in place. Therefore, in this embodiment, the pressure drop of the xenon gas passing through the high-temperature purifier 2 is assumed to be 0.1 MPa, assuming that the liquid xenon medium vaporizes at 1 MPa. Therefore, when the xenon gas liquefies at 0.9 MPa, the corresponding boiling point and liquefaction temperature are 218.6K and 215.4K, respectively, and the phase change heat is 79.7 kJ / kg and 81.0 kJ / kg, respectively. The key point of the first embodiment is to achieve a 215.4K cooling output using a high-grade cold source at 218.6K. Of course, actual systems must consider temperature differential losses and heat leakage during the heat exchange process.

[0046] The first gear pump 3A draws liquid xenon from the liquid xenon detector 1 via the first pipe 21 and increases its pressure to 1 MPa. The liquid then enters the cold-side input port 111 of the first heat exchanger 11 via the second pipe 22 and enters the low-temperature xenon coil 4A of the brine tank 4 via the third pipe 23. After heat exchange, it is heated by the first brine within and boils to form gaseous xenon. The gaseous xenon then enters the cold-side input port 121 of the second heat exchanger 12 via the fourth pipe 24, where it is further heated. It then enters the high-temperature purifier 2 via the fifth pipe 25. The high-temperature purifier 2 has a rated operating pressure of 1 MPa and an operating temperature of no less than 400°C. After purification by the high-temperature purifier 2, the gaseous xenon (target substance) is reduced in pressure to 0.9 MPa. The gaseous xenon enters the hot side of the second heat exchanger 12 via the sixth pipe 26 and enters the hot side of the second heat exchanger 12 from its hot-side input port 123, where it is cooled. The gaseous xenon then enters the primary liquefier 5 via the seventh pipe 27. The actual operating pressure within the primary liquefier 5 can be measured by the first pressure sensor 9. The corresponding liquefaction temperature of xenon gas at 0.9 MPa is 215.4 K. Designed for a 5 K subcooling, the rated evaporation temperature of the second refrigerator 7, i.e., the rated evaporation temperature of the liquefaction heat exchanger 5A within the primary liquefier 5, is set at 210 K. Due to the high efficiency of condensation heat transfer, the xenon gas can effectively condense on the surface of the liquefaction heat exchanger 5A and drip to the bottom of the primary liquefier 5, fully utilizing the cooling capacity of the second refrigerator 7. The liquid target material accumulated at the bottom of the primary liquefier 5 enters the eighth pipeline 28 under the combined effects of gravity and pressure, and then enters the hot-side input port 113 of the first heat exchanger 11 through the eighth pipeline 28.

[0047] During steady-state operation, the liquid xenon at a pressure of 0.9 MPa inside the hot side of the first heat exchanger 11 is further cooled by the liquid xenon at a pressure of 1 MPa on the cold side of the first heat exchanger 11, fully utilizing the high-quality cooling capacity of the first liquid xenon medium. The liquid xenon then enters the hot-side input port 131 of the third heat exchanger 13 via the ninth pipeline 29. The third refrigerator 8 outputs a low-temperature secondary refrigerant via the fifth secondary refrigerant pipeline 55 to the cold side of the third heat exchanger 13. The secondary refrigerant then returns to the third refrigerator 8 via the sixth secondary refrigerant pipeline 56 for recycling. The minimum output temperature of the third refrigerator 8 is below 170 K, allowing the liquid target material to be cooled to below 178 K, ensuring a certain degree of subcooling, corresponding to a vapor pressure below 0.2 MPa. This means that upon entering the liquid xenon detector 1, which has the lowest operating pressure in the system or device of the present invention, the subcooled liquid (liquid xenon) does not vaporize and does not introduce a heat load to the liquid xenon detector 1. Instead, it provides a certain amount of cooling capacity, reducing the burden on the refrigeration system of the liquid xenon detector 1.

[0048] After being finally cooled on the hot side of the third heat exchanger 13 , the liquid xenon (liquid target material) sequentially enters the tenth pipeline 30 , the second gear pump 3B, the eleventh pipeline 31 , and finally enters the liquid xenon detector 1 , thus completing the purification process.

[0049] In this embodiment, the rated evaporation temperature of the first refrigerator 6 is 238K, and the rated output temperature of the first refrigerant is not higher than 243K. The first refrigerator 6 outputs the low-temperature refrigerant (first refrigerant) to the refrigerant storage tank 4 through the first refrigerant pipe 51, and returns to the first refrigerator 6 for recycling through the second refrigerant pipe 52. The rated operating temperature of the refrigerant in the refrigerant storage tank 4 is 248K, wherein the first refrigerant can be anhydrous ethanol. The first refrigerator 6 can also use R404A refrigerant. When the water-cooled condensation temperature is 308K and the evaporation temperature is 238K, the refrigeration efficiency of the first refrigerator 6 can reach 1.7. During the system startup process of the present invention, all pipes and heat exchangers in contact with the xenon medium (target material) are first evacuated to 10 -4 Pa, then open the first valve 32 and the second valve 33. During normal operation, the pipes and heat exchangers that are in contact with the target material will inhale gas xenon from the liquid xenon detector 1 to 0.2 MPa, and then start the first refrigerator 6.

[0050] The first brine with a temperature of 248 K in the brine storage tank 4 enters the cold side of the condensing heat exchanger 74 through the third brine pipe 53 and the brine circulation pump 75 .

[0051] The first refrigerant is compressed to a high temperature and high pressure by compressor 71. It then flows through first refrigerant pipe 81 into water-cooled heat exchanger 72, where it is cooled to room temperature. It then flows through second refrigerant pipe 82 into the hot side of regenerative heat exchanger 73 for further cooling, and then through third refrigerant pipe 83 into the hot side of condensing heat exchanger 74. The first refrigerant on the hot side of condensing heat exchanger 74 is condensed and liquefied, achieving a certain degree of subcooling. After throttling through throttle valve 76 and cooling, it flows through fourth refrigerant pipe 84 into liquefier heat exchanger 5A, exchanges heat with the high-pressure xenon gas in primary liquefier 5, and then returns to the cold side of regenerative heat exchanger 73 through fifth refrigerant pipe 85. The higher-quality cooling energy is absorbed by the refrigerant on the hot side of regenerative heat exchanger 73. The cold side refrigerant is heated and then returns to compressor 71 through sixth refrigerant pipe 86. Regenerative heat exchanger 73 increases the refrigerant's superheat, prevents liquid hammer, improves the reliability of compressor 71, and enhances refrigeration efficiency. Second refrigerator 7 starts after first refrigerator 6 starts and the brine tank 4 reaches its rated temperature of 248K. The rated output temperature of second refrigerator 7 is 210K, which is the rated operating temperature of liquefied heat exchanger 5A. Alternatively, second refrigerator 7 can use brine for indirect cooling, lowering the evaporation temperature to 205K to compensate for heat exchange losses. In this design, the fluid input to liquefied heat exchanger 5A is a 210K low-temperature brine. Using brine improves the operating stability of second refrigerator 7, but at the expense of reduced cooling efficiency.

[0052] The rated output temperature of the third refrigerator 8 is not higher than 170K, its target temperature is lower, and the refrigeration time required to reach the rated temperature is longer. It can be started after the first refrigerator 6 is started and before the second refrigerator 7 is started to reduce the current impact of the compressor startup.

[0053] After the first, second, and third refrigerators 6, 7, and 8 are started and cooled to their rated temperatures, the first gear pump 3A is started at a low speed. Liquid xenon gradually cools the second pipeline 22 and the first heat exchanger 11. During the initial startup, some of the liquid xenon vaporizes, and all of the liquid xenon is completely vaporized within the low-temperature xenon coil 4A. The low-temperature xenon gas then gradually cools the fourth pipeline 24 and the second heat exchanger 12. During the initial system startup, the gaseous target material (xenon gas) entering the primary liquefier 5 is at a high temperature and low pressure. The target material on the surface of the liquefied heat exchanger 5A cannot condense and liquefy, resulting in low heat exchange efficiency and ineffective cooling of the xenon gas. The xenon enters the eighth pipeline 28 and subsequently the hot side of the first heat exchanger 11 in vapor form. At this time, because the temperature of the hot side of the third heat exchanger 13 is lower than 178K, it functions like a cryogenic adsorption pump, absorbing and liquefying the xenon gas through the ninth pipe 29, which accumulates inside the hot side of the third heat exchanger 13 until the liquid xenon completely fills the hot side of the third heat exchanger 13. Due to the poor thermal conductivity of the ninth pipe 29 and the xenon gas inside, the third refrigerator 8 is unable to cool the ninth pipe 29 and the xenon gas inside. As the first gear pump 3A continuously delivers liquid xenon, which vaporizes and enters the primary liquefier 5, the pressure of the xenon gas within the primary liquefier 5 gradually increases. At this point, a pressure differential develops between the input and output ends of the second gear pump 3B, gradually increasing. A small amount of liquid xenon or gaseous xenon passes through, but this is negligible compared to the mass flow of xenon delivered by the first gear pump 3A. After a period of time, the pressure of the second xenon gas within the primary liquefier 5 gradually rises to the rated pressure of 0.9 MPa. The corresponding liquefaction point of the xenon gas also gradually rises until it reaches or slightly exceeds the temperature of the liquefied heat exchanger 5A. The xenon gas begins to condense and drip on the surface of the liquefied heat exchanger 5A. The target xenon enters the eighth pipeline 28 and the hot side of the first heat exchanger 11 in a liquid phase or a gas-liquid mixed state, simultaneously cooling the eighth pipeline 28 and the first heat exchanger 11. Some of the liquid xenon vaporizes. Simultaneously, the liquid xenon output from the first gear pump 3A enters the cold side of the first heat exchanger 11, also having a cooling effect on the first heat exchanger 11. When the first heat exchanger 11 , the eighth pipe 28 , and the ninth pipe 29 are cooled to 215.5 K or lower, the purified second liquid xenon medium exists or flows in a pure liquid state.

[0054] After the xenon gas pressure in primary liquefier 5 reaches the rated pressure of 0.9 MPa, the starting motor of second gear pump 3B is slowly started and gradually increased in speed, simultaneously increasing the delivery rate of first gear pump 3A. When the speed of the drive motor of first gear pump 3A reaches the rated speed, the startup phase is completed and steady-state operation begins.

[0055] The shutdown process is much simpler. The first refrigerator 6, the second refrigerator 7, the third refrigerator 8, the first gear pump 3A, and the second gear pump 3B are turned off. High-pressure liquid xenon and high-pressure gas xenon slowly return to the liquid xenon detector 1 through the gaps inside the first gear pump 3A and the second gear pump 3B until the pressure is balanced.

[0056] The following is the thermodynamic calculation of the first embodiment: Because the present invention targets the cyclic purification of xenon as the target material, and the target xenon mass flow rate is constant at all locations on a timescale exceeding hours, calculations are based on the standard specific enthalpy of the target xenon. Approximate errors, system heat leakage, flow resistance, and other high-order variables that affect the specific enthalpy are accounted for in system efficiency. The pressure drop across the high-temperature purifier 2 and other related components is calculated as 0.1 MPa, meaning the output pressure of the first gear pump 3A is 1 MPa, and the rated operating pressure within the primary liquefier 5 is 0.9 MPa. During the engineering design and implementation phases, the actual cooling and heat exchange power requirements can be conveniently calculated based on the mass flow rate. Pipeline sizes and gear pump delivery rates are then selected based on the maximum mass and volume flow rates.

[0057] Since the heating effect of the first gear pump 3A on the liquid xenon can be ignored, at a temperature of 178K, the specific enthalpy of liquid xenon increases from 4.4kJ / kg to 4.6kJ / kg when the pressure is increased from 0.2MPa to 1MPa, and the isobaric specific heat capacity of liquid xenon changes very little in the range of 0.9MPa~1MPa, the mass flow rate of liquid xenon entering the cold side and the hot side of the first heat exchanger 11 is consistent and there is no phase change process, so a suitable heat exchanger model is selected to control the inlet and outlet logarithmic temperature difference at 5K and the heat exchange efficiency at 90% is feasible and reasonable. Calculations confirm that the liquid xenon leaving the cold side of the first heat exchanger 11 and entering the low-temperature xenon coil 4A has a pressure of 1 MPa, a temperature of 212 K, and a specific enthalpy of 16.7 kJ / kg. The saturated liquid xenon entering the hot side of the first heat exchanger 11 has a temperature of 215.4 K. The liquid xenon leaving the hot side of the first heat exchanger 11 through the ninth pipe 29 and entering the hot side of the third heat exchanger 13 has a temperature of 187 K, a pressure of 0.9 MPa, and a specific enthalpy of 7.0 kJ / kg. The primary function of the first heat exchanger 11 is to efficiently utilize high-quality cold sources, reducing the cooling power required by the third refrigerator 8.

[0058] The rated operating temperature of the first brine in brine tank 4 is 243K. At 212K, liquid xenon at a pressure of 1 MPa readily vaporizes within low-temperature xenon coil 4A. This vaporization process is a boiling heat exchange, resulting in a high heat exchange efficiency. However, the heat exchange between gaseous xenon and low-temperature xenon coil 4A is much lower than boiling heat exchange. Therefore, based on the specific enthalpy of dry saturated gaseous xenon at 1 MPa of 98.9 kJ / kg, and a temperature of 219K, the cooling capacity input to the first brine in brine tank 4 is 82.2 kJ / kg. First refrigerator 6 is primarily used for pre-cooling during the startup phase of the present invention and supplementary cooling of brine tank 4 during operation. Its rated power can be relatively low.

[0059] Both the cold and hot sides of the second heat exchanger 12 are filled with xenon gas. Considering the size of the heat exchanger, the design and calculation are based on a 5K temperature difference. The temperature of the xenon gas leaving the hot side of the second heat exchanger 12 and entering the primary liquefier 5 is approximately 224K. The corresponding specific enthalpy at 0.9 MPa is 101 kJ / kg. The specific enthalpy of saturated liquid xenon at 0.9 MPa is 17.8 kJ / kg. The cooling capacity required by the second refrigerator 7 for liquefaction is 83 kJ / kg.

[0060] Therefore, the cooling power requirement of the second refrigerator 7 is much greater than that of the first refrigerator 6 and the third refrigerator 8, and requires careful design. The water-cooled condenser 72 is preferentially used to cool the high-temperature and high-pressure refrigerant output by the compressor 71, and the heat exchanger 73 is used to further recover the cold energy. Then, the high-quality cold energy of the vaporized 1MPa liquid xenon is fully utilized through the first refrigerant in the condensing heat exchanger 74, thereby improving the cooling efficiency and reducing the equipment size.

[0061] The following is the calculation of pipeline flow resistance in the first embodiment: The next-generation PandaX dark matter detector is planned to use 20 tons of xenon. If it is purified once a day, the circulating mass flow rate is 231g / s. Taking into account the design margin and ease of calculation, it is designed based on a peak mass flow rate of 0.25kg / s. At around 178K, the liquid xenon density is about 2800kg / m³, corresponding to a peak volume flow rate of about 90ml / s.

[0062] First, second, and third pipes 21, 22, and 23 primarily carry liquid xenon, and require minimal flow resistance. At peak flow, the pressure drop needs to be controlled within 0.01 MPa. Liquid xenon at 178K has a viscosity of approximately 0.0004 Pa·s. A mass flow rate of 0.25 kg / s corresponds to a volume flow rate of approximately 90 ml / s. If a 1 / 2-inch stainless steel pipe with an inner diameter of 10 mm is used, the flow velocity is 1.1 m / s, the Reynolds number is approximately 79590, and the calculated resistance coefficient is 0.0188. The resistance drop per meter of pipe is 3.6 kPa, placing the pipe diameter and flow resistance within acceptable ranges.

[0063] The fourth, fifth, sixth, and seventh pipes 24, 25, 26, and 27 all flow xenon gas with a viscosity of approximately 20 uPa·s. They utilize a 1-inch hose with an inner diameter of 20 mm. The flow rate is approximately 3 L / s, the velocity is approximately 10 m / s, the Reynolds number is approximately 796,000, the resistance coefficient is approximately 0.014, and the pressure drop caused by each meter of pipe is approximately 2.7 kPa. Both the pipe diameter and the flow resistance are within acceptable ranges.

[0064] The primary liquefier 5 must operate at a high pressure to achieve a high liquefaction point. Therefore, the subsequent pipelines must have appropriate flow resistance to increase the pressure of the xenon gas within the primary liquefier 5. If the second gear pump 3B, which serves as the resistance-adjusting element, is an NP240 model, its leakage rate is 20 ml / s at a pressure differential of 1 MPa for a medium with a viscosity of 1 mPa·s, and exhibits good linearity, according to test data under 20°C pure water conditions. Therefore, the second gear pump 3B alone cannot provide flow resistance for the purified liquid xenon; other pipelines must also provide appropriate flow resistance.

[0065] The liquid xenon in the eighth pipe 28 has a low degree of subcooling. To prevent the liquid xenon from vaporizing during the flow process, the flow resistance should not be too large. It is appropriate to use 1 / 2-inch pipes together with the first pipe 21, the second pipe 22, and the third pipe 23, and the length should not be too long. The pressure drop of the ninth pipe 29, the tenth pipe 30, and the eleventh pipe 31 at the peak flow rate of the liquid xenon should be 0.2 MPa. A 1 / 4-inch stainless steel pipe with an inner diameter of 4.6 mm passes through a mass flow rate of 0.25 kg / s of liquid xenon at a flow rate of 5.4 m / s, and the pressure drop per meter of pipe is 0.17 MPa. The length of these pipes can be 1.1 to 1.2 m. In this way, the resistance required of the second gear pump 3B at the peak flow rate is only 0.2 MPa, and the corresponding leakage at static state is 4 ml / s, which is much less than the peak flow rate of 90 ml / s. Approximation errors, calculation errors, the effects of temperature changes on the viscosity and density of liquid xenon, and pressure drop changes caused by flow fluctuations can be compensated by adjusting the speed of the second gear pump 3B. At different drive speeds, the second gear pump 3B can act as a resistance element or a pressure-boosting element.

[0066] During the startup phase of the system of the present invention, the medium entering the eighth pipeline 28, the ninth pipeline 29, the tenth pipeline 30, and the eleventh pipeline 31 is gaseous xenon. Since the density of gaseous xenon is much lower, the mass flow rate through the same pipeline is much lower than that of liquid xenon for the same pressure difference. Therefore, these pipelines have a large flow resistance to gaseous xenon during the system startup phase, which is conducive to quickly increasing the gaseous xenon pressure in the primary liquefier 5.

[0067] As can be seen from the first embodiment, the vaporization temperature of 0.9 MPa gaseous xenon is low, and the liquefaction temperature is also relatively low, so a two-stage refrigerator (a second refrigerator and a first refrigerator) is required. In addition, the heat of vaporization of the first liquid xenon medium has a recoverable cooling value. Second embodiment

[0068] Compared to the first embodiment, the major change is that the design pressure of the high-temperature purifier 2 is increased from 1 MPa to 2.5 MPa, and the actual operating pressure can be increased from 0.9 MPa to 2 MPa. The rated output pressure of the first gear pump 3A is 2.1 MPa to 2.3 MPa. The rated pressure of the xenon gas in the primary liquefier 5 is 2 MPa. 2 MPa high-pressure xenon gas can be liquefied at 242.5K. The liquefaction process is the process that requires the most refrigeration power. Considering a subcooling of 5K, the minimum output temperature requirement of the liquefaction refrigerator is increased from 210K to 237K. This significantly simplifies the refrigeration system from cascade refrigeration to single-stage compression refrigeration with a single refrigerant, significantly improving refrigeration efficiency.

[0069] For example, in this embodiment, the refrigeration equipment only uses the fourth refrigerator. The evaporator design temperature of the fourth refrigerator 14 is 233K, and the rated output temperature of the refrigerant is 237K. The fourth refrigerator 14 outputs low-temperature refrigerant to the liquefied heat exchanger 5B through the seventh refrigerant pipe 57. The refrigerant is, for example, ethanol or other low-melting-point, non-toxic, and non-corrosive liquid, and then returns to the fourth refrigerator 14 through the eighth refrigerant pipe 58.

[0070] For xenon gas with a mass flow rate of 0.25 kg / s, the required refrigeration power for liquefaction is approximately 20 kW. If cooling water at 20°C and R404A refrigerant are used, the required compressor power is approximately 11 kW, the refrigeration power is approximately 21 kW, and the refrigeration efficiency is approximately 1.95, which is reasonable for the system requirements.

[0071] Because the rated working pressure of the primary liquefier 5 is increased from 0.9 MPa to 2 MPa, the pressure drop of the ninth pipeline 29, the tenth pipeline 30, and the eleventh pipeline 31 at peak flow needs to be increased from 0.2 MPa to about 0.6 MPa to reduce the pressure difference and leakage flow at both ends of the second gear pump 3B.

[0072] According to the principles of fluid mechanics, fluid resistance at the same mass flow rate is highly sensitive to pipe diameter. Calculations show that for smooth stainless steel pipes with internal diameters of 3mm, 3.5mm, 4mm, and 4.6mm, the pressure drops per meter of pipe for a liquid xenon flow rate of 0.25kg / s are 1.3MPa, 0.63MPa, 0.3MPa, and 0.17MPa, respectively. The ninth, tenth, and eleventh pipes 29, 30, and 31 all utilize 2m long, 4mm-diameter stainless steel pipes. The total pressure drop at peak flow is 1.8MPa. The pressure required of the second gear pump 3B itself is relatively low, and the additional flow resistance caused by pipe joints and elbows can be adjusted to accommodate these uncertainties.

[0073] In the second embodiment, at a working pressure of 2 MPa, xenon has a relatively high vaporization temperature and a relatively high liquefaction temperature, thereby significantly simplifying the refrigerator structure from cascade refrigeration to single-refrigerant single-stage compression refrigeration. Refrigeration efficiency is also significantly improved. However, the recovery value of the cooling energy from the heat of vaporization is not high, and the first liquid xenon medium can directly enter the cold side of the second heat exchanger 12.

[0074] In summary, the present invention utilizes a gear pump to effectively pressurize liquid xenon (liquid target material). The density of the liquid target material (liquid xenon) is tens to hundreds of times greater than that of the gaseous target material (gas xenon). Compared to gas diaphragm pumps, this pump can achieve high mass flow and output pressure, requires less space, and has a longer lifespan. Furthermore, using a gear pump to pressurize the liquid target material increases the partial pressure of electronegative impurities such as H, O, N, and C in the gaseous target material entering the high-temperature purifier, facilitating chemical reactions with the functional materials in the high-temperature purifier or adsorbing impurity elements by the functional materials, resulting in improved purification. Furthermore, the target material's circulating mass flow rate is increased, resulting in more contact times per unit time between the target material and the high-temperature purifier. This shortens the average residence time of electronegative impurities such as H, O, N, and C within the liquid xenon detector, helping to reduce the total content of electronegative impurities in the target material within the liquid xenon detector. This also allows for a similar purity of the liquid target material, resulting in better detector performance. During the purification process, the target material's operating pressure is significantly higher than the detector's operating pressure, significantly lowering its boiling point or condensation point. This allows it to be liquefied using a refrigeration system with a higher rated output temperature, improving cooling efficiency and reducing the circulating purification system's requirements for the refrigeration equipment's output temperature and power, thereby increasing the feasibility of high-flow circulation purification. By combining the heating required for vaporizing the high-pressure liquid target material with the low-temperature condensation required by the refrigerator, and selecting the appropriate refrigerant and heat exchanger to fully utilize high-quality cooling capacity, system efficiency is improved, enhancing the feasibility of high-flow circulation purification. Furthermore, the high output pressure of the gear pump is insensitive to the flow resistance of the purifier, its associated piping, and the heat exchanger, allowing the use of a purifier with a high adsorption material content and a large adsorption surface area, further enhancing purification effectiveness.

[0075] The present invention has been described using the above-described embodiments. However, these embodiments are merely exemplary embodiments of the present invention. Furthermore, the technical features described above in the various embodiments of the present invention may be combined as long as they do not conflict with each other. It should be noted that the disclosed embodiments do not limit the scope of the present invention. On the contrary, modifications and improvements made without departing from the spirit and scope of the present invention are within the scope of patent protection.

Claims

1. A high-flow, high-temperature, and high-pressure purification device for liquid xenon detectors, characterized in that: The liquid xenon detector high-flow, high-temperature and high-pressure purification device comprises: a first gear pump connected to the liquid xenon detector via a first pipeline, configured to extract a first liquid xenon medium from the liquid xenon detector and output the medium after pressurization, wherein the absolute output pressure of the first gear pump is greater than or equal to three times the absolute operating pressure of the liquid xenon detector; a first heat exchanger, wherein the first liquid xenon medium outputted from the output end of the first gear pump enters the cold side of the first heat exchanger through the second pipe for heat exchange, and the cold side of the first heat exchanger outputs the first liquid xenon medium through the third pipe; The second heat exchanger inputs the first liquid xenon medium or the first gas xenon medium formed by vaporizing the first liquid xenon medium to the cold side of the second heat exchanger through a fourth pipeline, and outputs the first gas xenon medium from the cold side of the second heat exchanger after heat exchange; A high-temperature purifier, wherein the first xenon gas medium output from the cold side of the second heat exchanger enters the high-temperature purifier through a fifth pipeline for purification, enters the hot side of the second heat exchanger through a sixth pipeline for heat exchange, and is then output; The second xenon gas medium output from the hot side of the second heat exchanger enters the liquefaction module through the seventh pipeline for cooling and liquefaction, then enters the hot side of the first heat exchanger through the eighth pipeline for heat exchange before being output, and the absolute pressure of the second xenon gas medium leaving the hot side of the second heat exchanger and the second xenon gas medium in the liquefaction module when liquefied is 0.5 MPa or higher than the absolute operating pressure of the liquid xenon detector; a third heat exchanger, wherein the second liquid xenon medium output from the hot side of the first heat exchanger enters the hot side of the third heat exchanger through a ninth pipe for heat exchange and is cooled to a temperature below the rated operating temperature of the liquid xenon detector; The second gear pump, the second liquid xenon medium output from the hot side of the third heat exchanger enters the second gear pump through the tenth pipeline, and returns to the liquid xenon detector through the eleventh pipeline, and the second gear pump can operate in a boost state or a depressurization state.

2. The high-flow, high-temperature, and high-pressure liquid xenon detector purification device according to claim 1, characterized in that: The liquefaction module includes a primary liquefier and a liquefaction heat exchanger and a first pressure sensor disposed within the primary liquefier. The liquefaction heat exchanger is configured to perform heat exchange with a second xenon gas medium entering the primary liquefier to liquefy the second xenon gas medium. The first pressure sensor is configured to measure an actual operating pressure within the primary liquefier.

3. The high-flow, high-temperature, and high-pressure liquid xenon detector purification device according to claim 2, characterized in that: It also includes the thermal management system, which includes a refrigerant storage tank, a low-temperature xenon coil, a first refrigerator and a second refrigerator. The low-temperature xenon coil is arranged in the refrigerant storage tank, and the input end of the low-temperature xenon coil is connected to the cold side of the first heat exchanger through the third pipe, and the output end of the low-temperature xenon coil is connected to the cold side of the second heat exchanger through the fourth pipe. The first refrigerator delivers the first refrigerant to the refrigerant storage tank through the first refrigerant pipe, and the first refrigerant that completes the heat exchange returns to the first refrigerator through the second refrigerant pipe; the second refrigerator is connected between the refrigerant storage tank and the primary liquefier, and the second refrigerator outputs the first refrigerant to the liquefied heat exchanger through the fourth refrigerant pipe, and the first refrigerant that completes the heat exchange returns to the second refrigerator through the fifth refrigerant pipe.

4. The high-flow, high-temperature, and high-pressure liquid xenon detector purification device according to claim 3, characterized in that: The second refrigerator includes a compressor, a water-cooled heat exchanger, a regenerative heat exchanger, a condensing heat exchanger, a refrigerant circulation pump, and a first throttle valve. The first refrigerant in the refrigerant storage tank enters the cold side of the condensing heat exchanger through a third refrigerant pipe and the refrigerant circulation pump, and after completing the heat exchange, flows back to the refrigerant storage tank through a fourth refrigerant pipe. After being compressed to a high-temperature and high-pressure state by the compressor, the first refrigerant enters the water-cooled heat exchanger through the first refrigerant pipe for cooling, and then enters the regenerative heat exchanger through the second refrigerant pipe for further cooling, and then enters the hot side of the condensing heat exchanger through the third refrigerant pipe. The first refrigerant entering the hot side of the condensing heat exchanger is condensed and liquefied and throttled by the first throttle valve for cooling. It enters the liquefied heat exchanger and exchanges heat with the second xenon gas medium in the primary liquefier, and then returns to the cold side of the regenerative heat exchanger through the fifth refrigerant pipe. The first refrigerant entering the cold side of the regenerative heat exchanger returns to the compressor through the sixth refrigerant pipe for recycling after undergoing heat exchange.

5. The high-flow, high-temperature, and high-pressure liquid xenon detector purification device according to claim 2, characterized in that: The pressure drop caused by the flow resistance of the liquid xenon medium in the first, second, third, and eighth pipelines at the rated mass flow rate should be less than 10 kPa; the pressure drop caused by the flow resistance of the gaseous xenon medium in the fourth, fifth, sixth, and seventh pipelines at the rated mass flow rate should be less than 10 kPa; the sum of the pressure drops caused by the flow resistance of the liquid xenon medium in the ninth and tenth pipelines at the rated mass flow rate should be within the range of 50% to 100% of the difference between the rated working pressures of the primary liquefier and the liquid xenon detector; the pressure drop caused by the flow resistance of the liquid xenon medium in the eleventh pipeline at the rated mass flow rate should be within the range of 25% to 100% of the difference between the rated working pressures of the primary liquefier and the liquid xenon detector.

6. The high-flow, high-temperature, and high-pressure liquid xenon detector purification device according to claim 2, characterized in that: It also includes a third refrigerator, the rated output temperature of the refrigerant of the third refrigerator is lower than the rated operating temperature of the liquid xenon detector, and the second refrigerant output by the third refrigerator enters the cold side of the third heat exchanger through the fifth refrigerant pipeline, and returns to the third refrigerator through the sixth refrigerant pipeline after completing the heat exchange.

7. The high-flow, high-temperature, and high-pressure liquid xenon detector purification device according to claim 6, characterized in that: The first pipeline is provided with a first valve, and the eleventh pipeline is provided with a second valve; all heat exchangers and pipelines in contact with the liquid xenon medium and the gas xenon medium are evacuated to a pressure of 10 -4 When the pressure in all heat exchangers and pipelines in contact with the liquid xenon medium and the gaseous xenon medium reaches the pressure at the input end of the first gear pump, the first refrigerator is started; then the third refrigerator is started, and when the temperature in the brine tank reaches the rated operating temperature of the first brine, the second refrigerator is started; subsequently, when the first refrigerator, the second refrigerator, and the third refrigerator have all cooled to their respective rated operating temperatures, the first gear pump is started at a low speed, and after stabilization, the speed of the drive motor of the first gear pump is gradually increased; until the gaseous xenon pressure in the primary liquefier reaches the rated operating pressure of the primary liquefier, the drive motor of the second gear pump is started and adjusted to an appropriate speed according to the actual pressure of the primary liquefier, and then the speed of the drive motor of the first gear pump is slowly increased to reach the rated speed, and the speed of the drive motor of the second gear pump is increased accordingly.

8. The high-flow, high-temperature, and high-pressure liquid xenon detector purification device according to claim 2, characterized in that: The system further includes a fourth refrigerator, which delivers a third refrigerant to the liquefied heat exchanger through a seventh refrigerant pipe. The third refrigerant that completes the heat exchange returns to the fourth refrigerator through an eighth refrigerant pipe. The rated output temperature of the third refrigerant of the fourth refrigerator is a first temperature, which is 5 to 10°C lower than the liquefaction temperature or boiling temperature of the xenon gas medium at the first pressure. The first pressure is the rated working pressure of the primary liquefier.

9. The high-flow, high-temperature, and high-pressure liquid xenon detector purification device according to claim 1, characterized in that: The target substance xenon entering the eighth pipe is in liquid, gaseous or gas-liquid mixture.

10. A method for purifying a liquid xenon detector at a high flow rate, high temperature and high pressure using the liquid xenon detector high flow rate, high temperature and high pressure purification device according to any one of claims 1 to 9, characterized in that: The high-flow, high-temperature, and high-pressure purification method for a liquid xenon detector comprises: Step S1, the first gear pump extracts the first liquid xenon medium from the liquid xenon detector through the first pipeline and outputs the liquid xenon medium after pressurization; Step S2: the first liquid xenon medium outputted from the output end of the first gear pump enters the cold side of the first heat exchanger through the second pipe for heat exchange and is outputted through the third pipe; Step S3: Inputting the first liquid xenon medium or the first gas xenon medium vaporized from the first liquid xenon medium into the cold side of the second heat exchanger through the fourth pipe, and outputting the first gas xenon medium from the cold side of the second heat exchanger after heat exchange; Step S4: the first xenon gas medium output from the cold side of the second heat exchanger enters the high-temperature purifier through the fifth pipeline for purification, and then enters the hot side of the second heat exchanger through the sixth pipeline for heat exchange; Step S5: the second xenon gas medium output from the hot side of the second heat exchanger enters the liquefaction module through the seventh pipeline for cooling and liquefaction, and then enters the hot side of the first heat exchanger through the eighth pipeline for heat exchange; Step S6: the second liquid xenon medium output from the hot side of the first heat exchanger enters the hot side of the third heat exchanger through a ninth pipe for heat exchange and is cooled to a temperature below the rated operating temperature of the liquid xenon detector; In step S7, the second liquid xenon medium outputted from the hot side of the third heat exchanger enters the second gear pump through the tenth pipeline and returns to the liquid xenon detector through the eleventh pipeline.

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