Apparatus and method for producing supercooled liquid argon

Abstract

The application discloses a device and method for preparing supercooled liquid argon, and the device is a device for preparing supercooled liquid argon, which can prepare supercooled low-temperature liquid argon and keep supercooling degree, and specifically comprises a hydrogen medium sandwich container and a gas pressure control chamber. The hydrogen medium sandwich container is connected with the gas pressure control chamber through a capillary. The gas pressure control chamber contains hydrogen temperature swing adsorption material (MOFs) and a semiconductor temperature control element, the temperature of the MOFs can be adjusted through the semiconductor temperature control element, the adsorption amount of hydrogen of the MOFs is changed, the gas pressure of the sandwich layer is changed, and the cooling rate is controlled.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of supercooled cryogenic fluid preparation, and particularly relates to a device and method for preparing supercooled liquid argon. BACKGROUND

[0002] In the field of low-temperature heat transfer, such as low-temperature biological preservation and low-temperature superconducting, high-speed cooling is required. When a saturated cryogenic fluid is used to cool an object with a large temperature difference, a vapor layer is generated due to the violent gasification, which causes the heat transfer condition to deteriorate sharply, and the cooling speed is difficult to meet the use requirement. Therefore, the supercooled cryogenic fluid is used for cooling to suppress the generation of the vapor layer and achieve rapid cooling, which is of great significance to high-speed low-temperature heat transfer.

[0003] At present, most of the supercooled cryogenic fluid preparation methods change the pressure to guide the supercooling of saturated liquid or use a low-temperature gas to cool the saturated liquid, and the methods are complex, difficult to operate, and unstable in product quality, which are not suitable for commercial application. Therefore, in order to meet the need of simply preparing the supercooled cryogenic fluid and reduce the cost of preparing the supercooled cryogenic fluid, a simple and easy supercooled cryogenic fluid preparation method is urgently needed. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a device and method to solve the technical problems of complex method, difficult operation, unstable product quality, and unsuitable for commercial application in the related art.

[0005] According to a first aspect of the embodiments of the present application, a device for preparing supercooled liquid argon is provided, which comprises a liquid-liquid heat exchange unit and a pressure control unit, and specifically comprises a liquid nitrogen tank, a hydrogen interlayer container, thermal insulation material, a capillary tube, a gas pressure control chamber, a hydrogen temperature swing adsorbent, and a semiconductor temperature control element.

[0006] The liquid-liquid heat exchange unit comprises the liquid nitrogen tank and the hydrogen interlayer container; the hydrogen interlayer container is used to contain liquid argon solution, and the upper port thereof is covered with thermal insulation material for heat preservation of the liquid argon and preventing heat leakage; the liquid nitrogen tank is used to contain saturated liquid nitrogen, and the hydrogen interlayer container is placed in the liquid nitrogen, with the upper port of the container being higher than the liquid level of the liquid nitrogen.

[0007] The pressure control unit comprises the gas pressure control chamber, the hydrogen temperature swing adsorbent, and the semiconductor temperature control element; the semiconductor temperature control element is arranged at the hydrogen temperature swing adsorbent, and is used to control the temperature and the amount of adsorbed hydrogen of the hydrogen temperature swing adsorbent, thereby controlling the cooling rate and the temperature of the liquid argon.

[0008] The gas pressure control chamber of the pressure control unit is connected to the hydrogen interlayer container of the liquid-liquid heat exchange unit through the capillary tube, so that the hydrogen pressure in the hydrogen interlayer container to be controlled is consistent with the hydrogen pressure in the gas pressure control chamber.

[0009] By setting the temperature setting value of the semiconductor temperature control element, the hydrogen adsorption amount of the hydrogen temperature swing adsorbent can be adjusted, the hydrogen pressure in the pressure control chamber and the hydrogen interlayer container interlayer can be controlled, the heat transfer amount of the liquid argon to the liquid nitrogen can be controlled, and the liquid argon cooling rate and the liquid argon temperature can be controlled.

[0010] Further, the contact surface of the semiconductor temperature control element and the pressure control chamber is coated with a heat-conducting paste for temperature control of the hydrogen temperature swing adsorbent.

[0011] Further, the device has a supercooling degree maintaining function to avoid the generation of solid argon due to excessive supercooling degree.

[0012] According to a second aspect of the embodiments of the present application, a method for preparing supercooled liquid argon is provided, which comprises the following steps:

[0013] (1) Liquid argon cooling: set the temperature value of the semiconductor temperature control element, heat the hydrogen temperature swing adsorbent to 35-40 DEG C, and then desorb hydrogen from the hydrogen temperature swing adsorbent, so that the hydrogen pressure in the pressure control chamber and the hydrogen interlayer container interlayer is as high as 9-10 Pa, and the difference between the heat release amount of the liquid argon in the hydrogen interlayer container to the liquid nitrogen in the liquid nitrogen tank and the heat leakage amount of the environment to the liquid argon in the hydrogen interlayer container is as high as 0.9 W / m 2 , and the initial cooling rate of the liquid argon is 0.69 K / h, which continues until 3 DEG C supercooling is generated;

[0014] (2) Supercooled liquid argon heat preservation: re-set the temperature value of the semiconductor temperature control element, and the temperature of the hydrogen temperature swing adsorbent is as low as 5-10 DEG C, the hydrogen temperature swing adsorbent adsorbs hydrogen from the pressure control chamber and the hydrogen interlayer container interlayer, the hydrogen pressure is as low as 5-6 Pa, and the heat release amount of the liquid argon in the hydrogen interlayer container to the liquid nitrogen in the liquid nitrogen tank is as low as 0.9 W / m 2 , so that the heat release amount of the liquid argon in the hydrogen interlayer container to the liquid nitrogen in the liquid nitrogen tank is equal to the heat leakage amount of the environment to the liquid argon in the hydrogen interlayer container.

[0015] In view of the problems of the existing preparation method using gas cooling or pressure change, which leads to complex equipment and unstable product quality, the present application provides a liquid-liquid heat exchanger for preparing supercooled low-temperature liquid argon. The device only needs to adjust the semiconductor temperature control element knob to change the heat transfer rate, meet the supercooling preparation and supercooling degree maintenance requirements of low-temperature fluid. The technical problem solved by the present application is to simplify the complexity of the supercooled low-temperature fluid preparation device.

[0016] The present application is realized by the following technical scheme:

[0017] Compared with the prior art, the present application has the following beneficial technical effects:

[0018] This invention provides a liquid-liquid heat exchanger and auxiliary device, which can utilize liquid nitrogen to cool liquid argon to achieve liquid-liquid heat exchange for the preparation of subcooled cryogenic fluids. It includes a liquid nitrogen tank, a hydrogen jacketed container, and a pressure control chamber. The liquid nitrogen tank contains saturated liquid nitrogen, providing a constant-temperature cooling source for the preparation process; the hydrogen jacketed container acts as a heat exchanger, and the cooling rate can be changed by adjusting the hydrogen pressure in the jacket; the pressure control chamber contains a hydrogen temperature-changing adsorbent and a semiconductor temperature control element, and is connected to the jacket of the hydrogen jacketed container via a capillary tube; by setting the temperature of the semiconductor temperature control element to regulate the temperature of the hydrogen temperature-changing adsorbent, the hydrogen pressure in the jacket of the hydrogen jacketed container is changed, controlling the cooling rate of the liquid argon, thereby achieving the preparation of subcooled liquid argon and maintaining the subcooling.

[0019] The beneficial effects of this invention are as follows:

[0020] This invention provides a liquid-liquid heat exchanger and auxiliary device, which can utilize liquid nitrogen to cool liquid argon to achieve liquid-liquid heat exchange for the preparation of subcooled cryogenic fluids. It includes a liquid nitrogen tank, a hydrogen jacketed container, and a pressure control chamber. The liquid nitrogen tank contains saturated liquid nitrogen, providing a constant-temperature cooling source for the preparation process; the hydrogen jacketed container acts as a heat exchanger, and the cooling rate can be changed by adjusting the hydrogen pressure in the jacket; the pressure control chamber contains a hydrogen temperature-changing adsorbent and a semiconductor temperature control element, and is connected to the jacket of the hydrogen jacketed container via a capillary tube; by setting the temperature of the semiconductor temperature control element to regulate the temperature of the hydrogen temperature-changing adsorbent, the hydrogen pressure in the jacket of the hydrogen jacketed container is changed, controlling the cooling rate of the liquid argon, thereby achieving the preparation of subcooled liquid argon and maintaining the subcooling. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0022] Figure 1 This is a schematic diagram of an apparatus for preparing supercooled liquid argon according to the present invention;

[0023] Figure 2 This is a graph showing the relationship between heat transfer per unit area of ​​the interlayer, pressure, and adsorbent temperature (when the temperature difference between liquid argon and saturated liquid nitrogen is 10K).

[0024] Figure 3 This is a graph showing the relationship between the heat transfer per unit area of ​​the interlayer, pressure, and adsorbent temperature (when the temperature difference between liquid argon and saturated liquid nitrogen is 7K).

[0025] Figure labels: 1-Liquid nitrogen tank, 2-Hydrogen jacketed container, 3-Insulation material, 4-Capillary tube, 5-Pressure control chamber, 6-Hydrogen temperature-changing adsorbent, 7-Semiconductor temperature control element. Detailed Implementation

[0026] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] The present invention will now be described in further detail with reference to the accompanying drawings:

[0029] like Figure 1 As shown, this embodiment includes a liquid nitrogen tank 1, a hydrogen jacketed container 2, and a pressure control chamber 5. The hydrogen jacketed container 2 is used to contain liquid argon solution, and its upper port is covered with insulation material 3 to keep the liquid argon warm and prevent heat leakage. The liquid nitrogen tank 1 is used to hold saturated liquid nitrogen, and the hydrogen jacketed container 2 is placed in the liquid nitrogen, with its upper opening higher than the liquid nitrogen level. The pressure control chamber 5 includes a hydrogen temperature-changing adsorbent 6 and a semiconductor temperature control element 7, which is connected to the jacketed pipe of the hydrogen jacketed container 2 through a capillary tube 4. The semiconductor temperature control element 7 is arranged at the hydrogen temperature-changing adsorbent, and thermal conductive paste is applied to the contact surface between the semiconductor temperature control element 7 and the pressure control chamber 5 to control the temperature of the hydrogen temperature-changing adsorbent 6.

[0030] In practical use, it can be divided into a liquid argon cooling stage and a subcooled liquid argon insulation stage.

[0031] During the liquid argon cooling stage, the temperature value of the semiconductor temperature control element 7 is set, causing the hydrogen temperature-changing adsorbent 6 to heat up. Hydrogen desorbs from the hydrogen temperature-changing adsorbent 6, increasing the hydrogen pressure in the pressure control chamber 5 and the jacket of the hydrogen jacketed container 2. The liquid argon in the hydrogen jacketed container 2 releases a large amount of heat to the liquid nitrogen in the liquid nitrogen tank 1. The heat released is greater than the heat leakage from the environment to the liquid argon in the hydrogen jacketed container 2, causing the liquid argon to continuously cool down and generate supercooling. The supercooling refers to the temperature difference from the saturation temperature.

[0032] In the super-cooled liquid argon holding stage, the temperature value of the semiconductor temperature control element 7 is reset, the temperature of the hydrogen temperature swing adsorbent 6 is reduced, the hydrogen temperature swing adsorbent 6 adsorbs the hydrogen in the interlayer of the gas pressure control chamber 5 and the hydrogen interlayer container 2, the hydrogen pressure is reduced, the heat release of the liquid argon in the hydrogen interlayer container 2 to the liquid nitrogen in the liquid nitrogen tank 1 is reduced, so that the heat release of the liquid argon in the hydrogen interlayer container 2 to the liquid nitrogen in the liquid nitrogen tank 1 is equal to the heat leakage of the environment to the liquid argon in the hydrogen interlayer container 2.

[0033] As shown in Figure 2 , specifically, in the liquid argon cooling stage, for the hydrogen interlayer container 2 with a side vacuum layer thickness of 10 mm, a bottom vacuum layer thickness of 100 mm, a wall thickness of 0.6 mm of stainless steel material, and containing 300 ml of saturated liquid argon, covered with a 50 mm thick heat preservation material 3, placed in a liquid nitrogen tank 1 containing saturated liquid nitrogen, in the gas pressure control chamber 5, Mg-X is used as the hydrogen temperature swing adsorbent 6, when the temperature of the hydrogen temperature swing adsorbent 6 is 40℃, the hydrogen pressure in the hydrogen interlayer container 2 is 10 Pa, in the initial cooling stage, the temperature of the saturated liquid argon is 87.3 K, the temperature of the saturated liquid nitrogen is 77.4 K, the initial heat transfer temperature difference between the liquid argon and the liquid nitrogen is about 10 K, and the heat transfer rate through the hydrogen interlayer reaches 1.7 W / m 2 As shown in Figure 2 , the initial cooling rate of the liquid argon reaches 0.69 K / h. After 5 hours, 300 ml of liquid argon in the hydrogen interlayer container 2 can be cooled from 87.3 K to 84.1 K; in the super-cooled liquid argon holding stage, the temperature setting value of the semiconductor temperature control element 7 is changed, because the adsorption equilibrium constant of the hydrogen temperature swing adsorbent 6 changes dramatically with temperature in an exponential relationship, the hydrogen in the interlayer of the gas pressure control chamber 5 and the hydrogen interlayer container 2 is adsorbed by the hydrogen temperature swing adsorbent 6, and the heat conduction in the intermediate pressure zone is closely related to the pressure, so the heat transfer rate will decrease with the decrease of the pressure. When the temperature of the hydrogen temperature swing adsorbent 6 is reduced to 40℃, the hydrogen pressure in the interlayer of the hydrogen interlayer container 2 can be reduced to 5 Pa, at this time the super-cooled liquid argon temperature is 84.1 K, the saturated liquid nitrogen is still 77.4 K, the heat transfer temperature difference between the liquid argon and the liquid nitrogen is about 7 K, and the heat transfer rate through the hydrogen interlayer is reduced to 0.8 W / m 2 As shown in Figure 3 , at this time the heat release of the liquid argon in the hydrogen interlayer container 2 to the liquid nitrogen in the liquid nitrogen tank 1 is equal to the heat leakage of the environment to the liquid argon in the hydrogen interlayer container 2, so that the super-cooled liquid argon is kept at a constant temperature, avoiding the formation of solid argon.

[0034] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that the specific embodiments of the present application can still be modified or replaced by equivalents without departing from the spirit and scope of the present application, any modification or equivalent replacement should be covered within the protection scope of the claims of the present application.

[0035] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the application embrace any and all variations of the present application that fall within the scope of the general inventive concept as defined in the claims and that the application may be practiced otherwise than is specifically described herein. Any reference to claim limitations in the specification shall not be construed as applying only to the specific claim section. The specification and drawings should be considered in a descriptive sense only and not limiting on the scope of the present application.

[0036] It is to be understood that the application is not limited to the precise structures herein described and illustrated in the drawings and that various modifications and changes can be made without departing from the scope thereof.

Claims

1. An apparatus for preparing supercooled liquid argon, characterized in that, The device includes a liquid-liquid heat exchange unit and a pressure control unit; specifically, it includes a liquid nitrogen tank (1), a hydrogen jacketed container (2), insulation material (3), a capillary tube (4), a pressure control chamber (5), a hydrogen temperature-changing adsorbent (6), and a semiconductor temperature control element (7). The liquid-liquid heat exchange unit includes a liquid nitrogen tank (1) and a hydrogen jacketed container (2); the hydrogen jacketed container (2) is used to hold liquid argon solution, and its upper port is covered with heat-insulating material (3) to keep the liquid argon warm and prevent heat leakage; the liquid nitrogen tank (1) is used to hold saturated liquid nitrogen, and the hydrogen jacketed container (2) is placed in liquid nitrogen, with its upper opening higher than the liquid nitrogen surface; The pressure control unit includes a pressure control chamber (5), a hydrogen temperature-changing adsorbent (6), and a semiconductor temperature control element (7); the semiconductor temperature control element (7) is arranged at the hydrogen temperature-changing adsorbent (6) to control the temperature of the hydrogen temperature-changing adsorbent (6) and the amount of hydrogen adsorbed, thereby controlling the liquid argon cooling rate and the liquid argon temperature. The pressure control chamber (5) of the pressure control unit is connected to the jacketed pipe of the hydrogen jacketed container (2) through a capillary tube (4), so that the hydrogen pressure in the hydrogen jacketed container (2) is consistent with the hydrogen pressure in the pressure control chamber (5). By setting the temperature setpoint of the semiconductor temperature control element (7), the amount of hydrogen adsorbed by the hydrogen temperature-changing adsorbent (6) is adjusted, thereby controlling the hydrogen pressure in the pressure control chamber (5) and the hydrogen jacket container (2), and thus controlling the heat transfer from liquid argon to liquid nitrogen, as well as the cooling rate of liquid argon, and controlling the temperature of liquid argon.

2. The apparatus for preparing supercooled liquid argon according to claim 1, characterized in that, The contact surface between the semiconductor temperature control element (7) and the pressure control chamber (5) is coated with thermally conductive paste for temperature control of the hydrogen temperature-changing adsorbent (6).

3. The apparatus for preparing supercooled liquid argon according to claim 1, characterized in that, The device has a supercooling maintenance function to prevent the formation of solid argon from excessive supercooling.

4. A method for preparing supercooled liquid argon, which is used in the apparatus described in any one of claims 1-3, characterized in that, The method includes the following steps: (1) Liquid argon cooling: Set the temperature value of the semiconductor temperature control element (7) to heat the hydrogen temperature-changing adsorbent (6) to 35℃-40℃, and then the hydrogen desorbs from the hydrogen temperature-changing adsorbent (6). The hydrogen pressure in the pressure control chamber (5) and the jacket of the hydrogen jacket container (2) is as high as 9Pa-10Pa. The difference between the heat released by the liquid argon in the hydrogen jacket container (2) to the liquid nitrogen in the liquid nitrogen tank (1) and the heat leakage from the environment to the liquid argon in the hydrogen jacket container (2) is 0.9W / m 2 Liquid argon was cooled at an initial rate of 0.69 K / h until a supercooling of 3 °C was achieved. (2) Supercooled liquid argon insulation: The temperature value of the semiconductor temperature control element (7) is reset, the temperature of the hydrogen temperature-changing adsorbent (6) is reduced to 5-10℃, the hydrogen temperature-changing adsorbent (6) adsorbs hydrogen from the pressure control chamber (5) and the jacket of the hydrogen jacket container (2), the hydrogen pressure is reduced to 5Pa-6Pa, and the heat release from the liquid argon in the hydrogen jacket container (2) to the liquid nitrogen in the liquid nitrogen tank (1) is reduced to 0.9W / m 2 This ensures that the heat released from liquid argon in the hydrogen jacketed container (2) to liquid nitrogen in the liquid nitrogen tank (1) is equal to the heat leaked from the environment to liquid argon in the hydrogen jacketed container (2).

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