Device for preparing high-abundance argon isotope by taking high-purity argon as medium

Abstract

The invention discloses a device for preparing high-abundance argon isotope by taking high-purity argon as a medium, which comprises n stages of low-temperature rectification equipment arranged in series and a cascade pump arranged between two adjacent stages of low-temperature rectification equipment, each stage of low-temperature rectification equipment comprises a reboiler, a rectification unit and a condenser, the raw material of the n-stage low-temperature rectification equipment is high-purity argon with natural abundance; each rectification unit is formed by stacking a plurality of micro-tubes, in the rectification process of high-purity argon, the micro-tubes are used for providing liquid phase channels for liquid to flow, and external spaces outside the micro-tubes are configured to allow gas to flow; when n is greater than or equal to 2, inputting a heavy fraction product obtained at the heavy fraction end of the previous-stage rectification unit into a feeding inlet of the next-stage rectification unit through a cascade pump, condensing a light fraction product obtained at the light fraction end of the next-stage rectification unit into liquid through a condenser, and returning the liquid to the previous-stage rectification unit for rectification, according to the device, separation and purification of high-purity and high-abundance argon isotopes can be realized in a temperature control and modular cascade manner.

Description

Technical Field

[0001] The present application relates to the technical field of isotope separation, and in particular to a device for preparing high-abundance argon isotopes using high-purity argon as a medium. Background Art

[0002] Argon is a rare gas that exists naturally in three stable isotopes: 36Ar, 38Ar and 40Ar, with natural contents of 0.34%, 0.06% and 99.6%, respectively. The earliest discovered argon isotope is 40Ar, which is usually found in lava and rocks. In nature, the distribution and evolution of argon isotopes are affected by many factors, including the material cycle in the earth's interior, the evolution of the atmosphere, the circulation of water bodies and the action of the lithosphere. By studying the distribution and proportion of argon isotopes in different environments, we can explore the material cycle and evolution history of the earth's interior and the changes and evolution of the earth's surface environment. Argon isotopes are widely used as sensitive tracers in mineral deposit research to identify the source, evolution process and crust-mantle interaction of ore-forming fluids. Argon isotopes also play a certain role in the establishment of low-temperature temperature scales, providing support for research in the fields of physics and cryogenic engineering.

[0003] The main methods for separating argon isotopes are: thermal diffusion method and cryogenic distillation method. Thermal diffusion method is a method of separation based on the difference in thermal diffusion rate between isotopes. By heating a mixture containing argon isotopes, different isotopes are gradually separated due to different thermal diffusion rates. Cryogenic distillation method is a method of separation using the difference in boiling points of different isotopes at low temperatures. By lowering the temperature, different isotopes in the mixture are gradually separated at the boiling point, thereby achieving isotope purification.

[0004] The disadvantages of thermal diffusion separation of argon isotopes may include the following aspects: 1) Efficiency issues: Although thermal diffusion can separate isotopes based on the difference in thermal diffusion rates, the separation efficiency may be relatively low due to the relatively small mass difference between argon isotopes, which means that a longer time or more energy input is required to achieve the desired separation effect; 2) High energy consumption: Thermal diffusion requires maintaining a certain temperature gradient and achieving isotope separation through heating and cooling processes; 3) Complex equipment: Thermal diffusion usually requires the use of specialized equipment, such as thermal diffusion columns, which may have relatively high manufacturing and maintenance costs. At the same time, in order to ensure the stability and accuracy of the equipment, regular calibration and maintenance work is also required; 4) Separation purity limitations: Although thermal diffusion can separate argon isotopes, it may not be able to achieve very high purity. In some applications, such as scientific research or high-precision measurements, higher purity isotopes may be required. At this time, other more advanced separation technologies may need to be adopted.

[0005] Therefore, there is an urgent need in the art to develop a device for preparing high-abundance argon isotopes using high-purity argon as a medium, which can achieve separation and purification of high-purity, high-abundance argon isotopes through temperature control and modular cascade. Summary of the invention

[0006] The purpose of the present application is to provide a device for preparing high-abundance argon isotopes using high-purity argon as a medium, which can achieve separation and purification of high-purity, high-abundance argon isotopes through temperature control and modular cascade.

[0007] The present application provides a device for preparing high-abundance argon isotopes using high-purity argon as a medium, comprising:

[0008] n-stage cryogenic distillation equipment arranged in series, and a cascade pump arranged between two adjacent stages of cryogenic distillation equipment, each stage of cryogenic distillation equipment comprising a reboiler, a distillation unit and a condenser, wherein the raw material of the n-stage cryogenic distillation equipment is high-purity argon gas of natural abundance;

[0009] Each distillation unit includes a heavy fraction end and a light fraction end, and each distillation unit is formed by stacking a plurality of microtubes together. During the distillation process of the high-purity argon gas, the microtubes are used to provide a liquid phase channel for liquid flow, and the external space outside the microtubes is configured to allow gas flow;

[0010] When n≥2, the heavy fraction product obtained at the heavy fraction end of the previous distillation unit is input to the feed inlet of the next distillation unit through a cascade pump, and the light fraction product obtained at the light fraction end of the next distillation unit is condensed into liquid through the condenser and returned to the previous distillation unit for distillation. When the n-stage cryogenic distillation equipment is working, 40 Argon isotopes are enriched as heavy components at the heavy fraction end of the n-stage distillation unit and output.

[0011] In another preferred example, the diameter of the microtube is in the range of 0.3mm-1mm, and a gas-liquid exchange hole is provided on the tube wall of each microtube so that during the distillation process of the high-purity argon gas, the liquid flows in the liquid phase channel under the action of the capillary force of the microtube, the surface tension of the gas-liquid exchange hole and / or the gravity of the liquid, and the gas flows in the external space outside the microtube.

[0012] In another preferred embodiment, the distillation unit is placed horizontally, inclined, or vertically.

[0013] In another preferred example, during the distillation process, the high-purity argon gas condensed into liquid at the light fraction end flows in the liquid phase channel along the first axial direction of the distillation unit under the action of the capillary force of the microtube and the surface tension of the gas-liquid phase exchange holes, and the high-purity argon gas heated into gas at the heavy fraction end moves in the external space outside the microtube along the second axial direction of the distillation unit under the action of the pressure difference, and the second axial direction is opposite to the first axial direction.

[0014] In another preferred example, the first axial direction is a direction flowing from the light fraction end to the heavy fraction end, and the second axial direction is a direction flowing from the heavy fraction end to the light fraction end.

[0015] In another preferred example, the gas moves along the second axial direction, and the liquid moves along the first axial direction.

[0016] In another preferred embodiment, when the distillation units are placed vertically, the bottom of each distillation unit is in the same plane.

[0017] In another preferred example, the distillation unit further includes an outer shell, and the plurality of microtubes are arranged in the outer shell.

[0018] In another preferred embodiment, the heavy fraction end of the n-stage distillation unit of the n-stage cryogenic distillation equipment is enriched 40 The abundance of argon isotopes is greater than 99.99%.

[0019] In another preferred embodiment, n of the n-stage cryogenic distillation equipment is equal to 6, and the heavy fraction end of the sixth-stage distillation unit is enriched 40 The abundance of argon isotopes is greater than 99.99%.

[0020] In another preferred embodiment, the heavy fraction end of the second stage distillation unit is provided with an abundance higher than 99.92%. 40 The argon isotope product is fed as a feed to the third stage distillation unit, and an argon isotope with an abundance higher than 99.94% is obtained at the heavy fraction end of the third stage distillation unit. 40 Argon isotope products with abundances above 99.94% 40 The argon isotope product is fed as a feed to the fourth stage distillation unit, and an argon isotope product with an abundance higher than 99.96% is obtained at the heavy fraction end of the fourth stage distillation unit. 40 Argon isotope products with abundances above 99.96% 40 The argon isotope product is fed as a feed to the fifth stage distillation unit, and an argon isotope with an abundance higher than 99.97% is obtained at the bottom heavy fraction end of the fifth stage distillation unit. 40 Argon isotope products; abundance greater than 99.97% 40The argon isotope product is fed as a feed to the sixth stage distillation unit, and an argon isotope product with an abundance higher than 99.99% is obtained at the heavy fraction end of the bottom of the sixth stage distillation unit. 40 Argon isotope products.

[0021] In another preferred example, the microtube includes a gas-liquid exchange section. When the gas in the external space and the liquid in the liquid phase channel flow, heat and mass transfer are carried out in the gas-liquid exchange section of the microtube through the gas-liquid exchange holes, so that the heavy component gas located in the external space is converted into liquid and enters the liquid phase channel, and the light component liquid located in the liquid phase channel is converted into gas and enters the external space, and separation and purification are achieved by repeated reciprocation.

[0022] In another preferred example, during the distillation process, the plurality of microtubes are placed horizontally or tilted, and the heavy fraction end of the distillation unit and the light fraction end of the distillation unit are at substantially the same height level or at different height levels.

[0023] In another preferred embodiment, during the distillation process, the housing and the distillation unit are placed flat on a horizontal plane.

[0024] In another preferred embodiment, the plurality of microtubes are stacked together to form a cylinder, and the distance between the centers of two adjacent microtubes is in the range of 1 mm to 2 mm.

[0025] In another preferred embodiment, the plurality of microtubes are stacked together to form a column, and the cross section of the column is circular.

[0026] In another preferred embodiment, the plurality of microtubes have the same structure and size.

[0027] In another preferred embodiment, the length of the microtube is in the range of 500 mm-1000 mm.

[0028] In another preferred embodiment, the pore size of the gas-liquid exchange hole is in the range of 0.02 mm-0.05 mm.

[0029] In another preferred embodiment, the gas-liquid phase exchange holes are evenly arranged in the circumferential direction and the axial direction of the microtube.

[0030] In another preferred embodiment, the center distance between two adjacent gas-liquid exchange holes in the circumferential direction of the microtube is 0.05 mm-0.1 mm.

[0031] In another preferred embodiment, the capillary force should be greater than or equal to the gas-liquid phase pressure difference, and the gas-liquid phase pressure difference refers to the difference between the static pressure head of the liquid in the liquid phase channel and the static pressure head of the gas flowing in the external space outside the microtube.

[0032] In another preferred embodiment, the distance between two adjacent gas-liquid exchange holes on the microtube wall of the same cross section of the microtube is 0.05 mm-0.1 mm.

[0033] In another preferred embodiment, the center distance between two adjacent gas-liquid exchange holes in the axial direction of the microtube is 0.05 mm-0.1 mm.

[0034] In another preferred embodiment, 36 Argon, 38 The argon isotope product is obtained as a light component at the first light fraction end of the first-stage distillation unit and output as a product.

[0035] It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described below (such as embodiments) can be combined with each other to form a new or preferred technical solution. Due to space limitations, they will not be described one by one here. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. It should be understood that the drawings described below are only some implementation examples of the present invention, and ordinary technicians in this field can also obtain other implementation examples based on these drawings without paying creative work.

[0037] Figure 1 It is a schematic structural diagram of a device for preparing high-abundance argon isotopes using high-purity argon as a medium according to the present application;

[0038] Figure 2 It is a structural schematic diagram of a distillation unit (housing not shown) of a device for preparing high-abundance argon isotopes using high-purity argon as a medium according to the present application;

[0039] Figure 3 It is a partial structural schematic diagram of a distillation unit of a device for preparing high-abundance argon isotopes using high-purity argon as a medium according to the present application;

[0040] Figure 4 It is a schematic structural diagram of a micro-tube of a distillation unit of a device for preparing high-abundance argon isotopes using high-purity argon as a medium according to the present application.

[0041] In the accompanying drawings, the following are marked:

[0042] 1-Distillation unit

[0043] 11-Heavy fraction end

[0044] 12-Light fraction end

[0045] 2-Microtubules

[0046] 21-Gas-liquid phase exchange hole

[0047] 200-Liquid Phase Channel

[0048] 3-Reboiler

[0049] 4-Condenser

[0050] 5-Cascade Pump DETAILED DESCRIPTION

[0051] Through extensive and in-depth research, the inventors have developed for the first time a device for preparing high-abundance argon isotopes using high-purity argon as a medium. The device includes a distillation unit with an ingenious structure, and the distillation unit can be placed horizontally, tilted, or vertically. When the distillation unit is placed horizontally or slightly tilted, the ingenious structural setting of the distillation unit utilizes capillary force and surface tension to make the liquid flow in the microtube and the gas flow outside the microtube, and through the multiple holes set on the microtube, the heat and mass transfer of the gas-liquid phase is realized, which can be used for the separation of isotopes of high-purity argon. Furthermore, compared with traditional distillation towers, the equipment and system for ultra-high purity gas or isotope separation driven by capillary force in this application greatly reduces the space requirement in height, and has more practical engineering applications.

[0052] In the following description, many technical details are provided to help readers better understand the present application. However, those skilled in the art can understand that the technical solution claimed in the present application can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0053] the term

[0054] As used herein, the term “axial direction” refers to a direction along its length, and the term “circumferential direction” refers to a direction of its circumference, which is a direction perpendicular to the axial direction.

[0055] As used herein, a "distillation process" is a process that achieves separation based on the differences in boiling points of different isotopes of argon.

[0056] It should be noted that in the application documents of this patent, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including one" do not exclude the existence of other identical elements in the process, method, article or device including the elements. In the application documents of this patent, if it is mentioned that an action is performed according to an element, it means that the action is performed at least according to the element, which includes two situations: performing the action only according to the element, and performing the action according to the element and other elements. Expressions such as multiple, multiple, and multiple include 2, 2 times, 2 kinds, and more than 2, more than 2 times, and more than 2 kinds.

[0057] In the present invention, all directional indications (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0058] This application has at least one of the following advantages

[0059] (a) The device for preparing high-abundance argon isotopes using high-purity argon as a medium of the present application can enrich 40 The abundance of argon isotopes is greater than 99.99%;

[0060] (b) The size of the device for preparing high-abundance argon isotopes using high-purity argon as a medium of the present application is much smaller than that of a traditional distillation tower, and has more practical engineering applications;

[0061] (c) The device for preparing high-abundance argon isotopes using high-purity argon as a medium of the present application provides a distillation unit with an ingenious structure, which utilizes the combined effect of the capillary force and surface tension of the microtube and / or the gravity of the liquid to achieve the distillation process and improve the separation efficiency;

[0062] (d) The distillation unit in the device for preparing high-abundance argon isotopes using high-purity argon as a medium of the present application can achieve the purification of ultra-high purity gas and isotope separation by placing it horizontally or slightly tilted. Compared with the traditional distillation tower, it does not need to occupy space in the height direction and has more practical engineering applications.

[0063] See also Figure 1 , n-stage cryogenic distillation equipment arranged in series, and a cascade pump 5 arranged between two adjacent stages of cryogenic distillation equipment, each stage of cryogenic distillation equipment includes a reboiler 3, a distillation unit 1 and a condenser 4, and the raw material of the n-stage cryogenic distillation equipment is high-purity argon gas with natural abundance;

[0064] Each distillation unit 1 includes a heavy fraction end 11 and a light fraction end 12. Each distillation unit 1 is formed by stacking a plurality of microtubes 2. During the distillation process of high-purity argon, the microtubes 2 are used to provide a liquid phase channel 200 for liquid flow, and the external space outside the microtubes 2 is configured for gas flow.

[0065] When n≥2, the heavy fraction product obtained at the heavy fraction end of the previous distillation unit is input to the feed inlet of the next distillation unit through the cascade pump 5, and the light fraction product obtained at the light fraction end of the next distillation unit is condensed into liquid by the condenser and returned to the previous distillation unit for distillation. When the n-stage cryogenic distillation equipment is working, 40 Argon isotopes are enriched as heavy components at the heavy fraction end of the n-stage distillation unit and output.

[0066] Preferably, the diameter of the microtube 2 is in the range of 0.3 mm-1 mm, and a gas-liquid exchange hole 21 is provided on the tube wall of each microtube 2 so that during the distillation process of the high-purity argon gas, the liquid flows in the liquid phase channel 200 under the action of the capillary force of the microtube 2 and the surface tension of the gas-liquid exchange hole 21 and / or the gravity of the liquid, and the gas flows in the external space outside the microtube 2.

[0067] Preferably, the heavy fraction end of the n-stage distillation unit of the n-stage cryogenic distillation equipment is enriched 40 The abundance of argon isotopes is greater than 99.99%.

[0068] Preferably, when necessary, 36 Argon, 38 The argon isotope product is obtained as a light component at the first light fraction end of the first-stage distillation unit and output as a product.

[0069] In one embodiment, n of the n-stage cryogenic distillation device is equal to 6, and the heavy fraction end of the sixth stage distillation unit is enriched 40 The abundance of argon isotopes is greater than 99.99%.

[0070] In another preferred embodiment, the heavy fraction end of the second stage distillation unit is provided with an abundance higher than 99.92%. 40 The argon isotope product is fed as a feed to the third stage distillation unit, and an argon isotope with an abundance higher than 99.94% is obtained at the heavy fraction end of the third stage distillation unit. 40 Argon isotope products with abundances above 99.94% 40The argon isotope product is fed as a feed to the fourth stage distillation unit, and an argon isotope product with an abundance higher than 99.96% is obtained at the heavy fraction end of the fourth stage distillation unit. 40 Argon isotope products with abundances above 99.96% 40 The argon isotope product is fed as a feed to the fifth stage distillation unit, and an argon isotope with an abundance higher than 99.97% is obtained at the bottom heavy fraction end of the fifth stage distillation unit. 40 Argon isotope products; abundance greater than 99.97% 40 The argon isotope product is fed as a feed to the sixth stage distillation unit, and an argon isotope product with an abundance higher than 99.99% is obtained at the heavy fraction end of the bottom of the sixth stage distillation unit. 40 Argon isotope products.

[0071] Distillation unit

[0072] See also Figure 2-4 Each distillation unit 1 includes a heavy fraction end 11 and a light fraction end 12. During the distillation process, the high-purity argon gas condensed into liquid at the light fraction end 12 flows in the liquid phase channel 200 along the first axial direction of the distillation unit 1 under the action of the capillary force of the microtube 2 and the surface tension or gravity of the gas-liquid phase exchange hole 21, and the high-purity argon gas heated into gas at the heavy fraction end 11 moves in the second axial direction of the distillation unit 1 in the external space outside the microtube 2 under the action of the pressure difference. The second axial direction is opposite to the first axial direction. That is, the gas moves along the second axial direction, and the liquid moves along the first axial direction.

[0073] The first axial direction is a direction from the light fraction end 12 to the heavy fraction end 11 , and the second axial direction is a direction from the heavy fraction end 11 to the light fraction end 12 .

[0074] Preferably, the distillation unit 1 is placed horizontally, inclined, or vertically.

[0075] More preferably, the distillation unit 1 is placed horizontally or inclined.

[0076] To make the purpose, technical solution and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. It should be understood that these are only some examples that the present invention may take for the reader, but are not intended to limit the scope of the present invention.

[0077] See also Figure 1The present application provides a device for preparing high-abundance argon isotopes using high-purity argon as a medium, the device comprising n-stage cryogenic distillation equipment arranged in series, and a cascade pump 5 arranged between two adjacent stages of cryogenic distillation equipment, each stage of cryogenic distillation equipment comprising a reboiler 3, a distillation unit 1 and a condenser 4, the raw material of the n-stage cryogenic distillation equipment is high-purity argon gas of natural abundance;

[0078] Each distillation unit 1 includes a heavy fraction end 11 and a light fraction end 12. Each distillation unit 1 is formed by stacking a plurality of microtubes 2. During the distillation process of high-purity argon, the microtubes 2 are used to provide a liquid phase channel 200 for liquid flow, and the external space outside the microtubes 2 is configured for gas flow.

[0079] When n≥2, the heavy fraction product obtained at the heavy fraction end of the previous distillation unit is input to the feed inlet of the next distillation unit through the cascade pump 5, and the light fraction product obtained at the light fraction end of the next distillation unit is condensed into liquid by the condenser and returned to the previous distillation unit for distillation. When the n-stage cryogenic distillation equipment is working, 40 Argon isotopes are enriched and output as heavy components at the heavy fraction end of the n-stage distillation unit. 36 Argon, 38 The argon isotope product is obtained as a light component at the first light fraction end of the first-stage distillation unit and output as a product.

[0080] In one embodiment, the condenser 4 is located at the light fraction end 12 of the distillation unit and is configured to condense the heavy isotopes in the high-purity argon gas in a gaseous state into liquid, and the reboiler 3 is located at the heavy fraction end of the distillation unit and is configured to heat the light isotopes in the high-purity argon gas in a liquid state into gas. When the distillation starts, the gas is cooled and liquefied into liquid through the condenser 4 located at the light fraction end 22, and the liquid flows downward in the microtube to the heavy fraction end 11 of the distillation unit 1 by gravity (when the distillation unit is tilted) and capillary force, and the light components in the liquid at the heavy fraction end 11 are heated by the reboiler 3 to generate gas, and the gas flows toward the light fraction end 22 (along the second axial direction) outside the microtube by pressure difference to reach the light fraction end 22, and the gas-liquid flow process is carried out through the gas-liquid phase exchange hole 21 to transfer heat and mass to bring the heavy components to the liquid phase and the light components to the gas phase, and the separation and purification are achieved by repeated reciprocation.

[0081] In one embodiment, a device for preparing high-abundance argon isotopes using 99.99% high-purity argon as a medium is provided by the present application. 40 When argon isotope enrichment is performed, the following steps are included: using high-purity argon gas with natural abundance as raw material, supplying it to the first-stage distillation unit, and obtaining an argon isotope with an abundance higher than 99.7% at the heavy fraction end of the first-stage distillation unit. 40Argon isotope, and is fed into the second distillation unit as the feed of the second distillation unit; at the heavy fraction end of the second distillation unit, an argon isotope with an abundance higher than 99.92% is obtained. 40 Argon isotope products, the light fractions at the light fraction end of the second-stage distillation unit are returned to the inlet of the first-stage distillation unit and enter the distillation unit together with the raw materials for distillation; the abundance is higher than 99.92% 40 The argon isotope product is fed as a feed to the third-stage distillation unit, and an argon isotope with an abundance higher than 99.94% is obtained at the heavy fraction end of the third-stage distillation unit. 40 Argon isotope products, the light fractions at the light fraction end of the third stage distillation unit are returned to the inlet of the second stage distillation unit and enter the distillation unit together with the products obtained at the heavy fraction end of the first stage for distillation; the abundance is higher than 99.94% 40 The argon isotope product is fed as a feed to the fourth stage distillation unit, and an argon isotope with an abundance higher than 99.96% is obtained at the heavy fraction end of the fourth stage distillation unit. 40 Argon isotope products, the light fractions at the light fraction end of the fourth stage distillation unit are returned to the inlet of the third stage distillation unit and enter the distillation unit together with the products obtained at the second stage heavy fraction end for distillation; the abundance is higher than 99.96% 40 The argon isotope product is fed as a feed to the fifth-stage distillation unit, and an argon isotope with an abundance higher than 99.97% is obtained at the heavy fraction end of the fifth-stage distillation unit. 40 Argon isotope products, the light fractions at the light fraction end of the fifth stage distillation unit are returned to the inlet of the fourth stage distillation unit and enter the distillation unit together with the products obtained at the third stage heavy fraction end for distillation; the abundance is higher than 99.97% 40 The argon isotope product is fed as a feed to the sixth stage distillation unit, and an argon isotope with an abundance higher than 99.99% is obtained at the heavy fraction end of the sixth stage distillation unit. 40 The argon isotope product, the light fraction at the light fraction end of the fifth-stage distillation unit is returned to the inlet of the fifth-stage distillation unit and enters the distillation unit together with the product obtained at the fourth-stage heavy fraction end for distillation.

[0082] In one embodiment, the product at the light fraction end of the first-stage distillation unit is not recovered, and the light fractions at the second, third, fourth, fifth, and sixth-stage light fraction ends are all returned to the previous-stage distillation unit.

[0083] In one embodiment, the first stage distillation unit light fraction end enriched 36 Argon and 38 Argon can be purified by distillation in the same cascade process.

[0084] In one embodiment, the number of stages of the distillation unit corresponds to different argon isotope abundances, and the more stages there are, the higher the isotope abundance of the purified argon.

[0085] In one embodiment, before the natural abundance high-purity argon is supplied as raw material to the first-stage distillation unit, the method further includes: purifying the natural abundance argon raw material, specifically including the following steps: utilizing the difference in boiling point and saturated vapor pressure between argon and impurities to perform multiple distillation and purification on the argon raw material to increase the purity of the argon to above 99.99%.

[0086] In one embodiment, the energy consumption mainly comes from the reboiler, condenser and inter-stage pump work of each distillation unit.

[0087] In one embodiment, see Figure 2-4 The present invention discloses a device for preparing high-abundance argon isotopes using high-purity argon as a medium, comprising a distillation unit 1 and a housing (not shown), wherein the microtube distillation unit 1 is arranged in the housing, and the distillation unit 1 is formed by stacking a plurality of microtubes 2; the diameter of the microtube 2 is in the range of 0.3 mm to 1 mm, and a gas-liquid phase exchange hole 21 is arranged on the wall of each microtube 2, so that in the distillation process of high-purity argon, the microtube 2 provides a liquid phase channel 200 for liquid flow under the action of the capillary force of the microtube 2 and the surface tension of the gas-liquid phase exchange hole 21 and / or the gravity of the liquid, and the external space outside the microtube 2 is configured for gas flow; in one embodiment, the high-purity argon is 99.99% high-purity argon. The device can also be used to prepare high-abundance argon isotopes. Preferably, a plurality of microtubes 2 are stacked together to form a cylinder, and the center distance between two adjacent microtubes 2 is in the range of 1 mm to 2 mm. In one embodiment, when the distillation unit (ie, a plurality of microtubes) is placed horizontally, the microtubes 2 provide liquid phase channels 200 for liquid flow under the action of the capillary force of the microtubes 2 and the surface tension of the gas-liquid phase exchange holes 21 .

[0088] The distillation unit 1 has a heavy fraction end 11 and a light fraction end 12 opposite to the heavy fraction end 11, and the micro-tube heavy fraction end 11 and the light fraction end 12 are fixed by two sieve plates respectively. During the distillation process, the high-purity argon gas condensed into liquid at the light fraction end 12 flows in the liquid phase channel 200 along the first axial direction of the distillation unit 1 under the action of the capillary force of the micro-tube 2 and the surface tension of the gas-liquid phase exchange hole 21 and / or the gravity of the liquid, and the high-purity argon gas heated into gas at the heavy fraction end 11 moves in the second axial direction of the distillation unit 1 in the external space outside the micro-tube 2 under the action of the pressure difference, and the second axial direction is opposite to the first axial direction. That is, the gas moves along the second axial direction, and the liquid moves along the first axial direction. The first axial direction is the direction from the light fraction end 12 to the heavy fraction end 11, and the second axial direction is the direction from the heavy fraction end 11 to the light fraction end 12.

[0089] The microtube 2 includes a gas-liquid exchange section, and the gas-liquid exchange section of the microtube 2 is a part of the microtube 2. When the gas in the external space and the liquid in the liquid phase channel 200 flow, heat and mass transfer are carried out in the gas-liquid exchange section of the microtube 2 through the gas-liquid exchange hole 21, so that the heavy component gas in the external space is converted into liquid and enters the liquid phase channel 200, and the light component liquid in the liquid phase channel 200 is converted into gas and enters the external space. Specifically, the opening (gas-liquid exchange hole 21) on the tube wall is a gas-liquid exchange interface, which facilitates heat and mass transfer between gas and liquid. The liquid phase flows horizontally in the tube, and the gas phase flows horizontally outside the tube, and gas-liquid exchange is carried out at the opening.

[0090] In one embodiment, a plurality of microtubes 2 are placed horizontally or obliquely on a horizontal plane, that is, the distillation unit 1 is placed horizontally or slightly obliquely on a horizontal plane. By placing the distillation unit horizontally or obliquely to achieve distillation, compared with a traditional vertically placed distillation tower, the space requirement for height is low and it has more practical application value. The heavy fraction end 11 of the distillation unit 1 and the light fraction end 12 of the distillation unit are at the same height level or different height levels (in the case of oblique placement). In one embodiment, the inclination angle of the oblique placement can be 0-45 degrees. In one embodiment, when a plurality of microtubes 2 are placed horizontally on a horizontal plane, the first axial direction and the second axial direction are both parallel to the horizontal plane.

[0091] In one embodiment, the length of the micro tube 2 is in the range of 500 mm to 1000 mm as required.

[0092] In one embodiment, in order to achieve the desired gas-liquid mass transfer efficiency, a microtube 2 composed of uniform openings is constructed. By adjusting the spacing and pore size between the openings, the permeability between the microtubes 2 can be freely set. Based on the effective medium approximation theory (EMA), on a scale much larger than the opening spacing, such a microtube 2 can be considered to be uniform and isotropic with a constant effective permeability.

[0093] In the microtube structure, the key to preventing flooding is to control the pressure difference between the liquid phase and the gas phase, and to use capillary force to maintain the flow of liquid in the microchannel. Capillary force can absorb liquid into the microchannel (liquid phase channel 200). In order to prevent the liquid phase from entering the gas phase, the capillary force must be large enough to overcome the pressure difference between the gas phase and the liquid phase. This pressure difference is generated by the flow of liquid in the liquid phase channel 200.

[0094] The capillary force must be able to maintain the flow of the liquid in the liquid phase channel 200 without causing the liquid to overflow into the gas phase channel (the external space outside the microtube 2). This requires that the size and structure of the liquid phase channel 200 of the microtube be properly designed so that the liquid can flow stably in the microchannel.

[0095] The pressure difference generated by the flow of liquid in the liquid phase channel 200 is the same as the pressure difference between the gas and liquid phases. In the distillation unit composed of a plurality of microtubes 2 of the present application, the flow of liquid and gas is interrelated. The pressure difference generated by the flow of liquid in the liquid phase channel 200 must be balanced with the pressure difference between the gas and liquid phases to maintain a stable flow and separation process. If these two pressure differences are inconsistent, the flow of liquid or gas will be unstable, affecting the separation efficiency.

[0096] In the liquid phase channel 200, there is a phase interface between the liquid and the gas. Capillary force plays a key role at this phase interface, maintaining the flow of the liquid in the liquid phase channel 200 while preventing the liquid from entering the gas phase channel. The force balance at this phase interface requires that the pressure difference (capillary force) generated by the liquid flow matches the pressure difference between the gas and liquid phases.

[0097] The gas-liquid phase pressure difference ΔP is the difference between the liquid static pressure head and the vapor static pressure head:

[0098] ΔP=P liquid -P vapor =(ρ liquid -ρ vapor )·g·h

[0099] Among them, ρ liquid and ρ vapor are the liquid and vapor densities respectively, g is the gravitational acceleration, and h is the height of the liquid column, the height of the liquid in the direction of the microtube diameter.

[0100] The pressure difference due to capillary force is calculated as follows:

[0101] P cap =2γ / R

[0102] Wherein, γ is the tension coefficient of the liquid in the microtube, and R is the size and radius of the gas-liquid phase exchange hole 21 on the tube wall.

[0103] Therefore, in the design of the microtube 2, it is necessary to ensure that the capillary force is greater than or equal to the gas-liquid phase pressure difference. Based on the above, preferably, the microtube 2 is set to the following size, the gas-liquid phase exchange holes 21 are evenly arranged in the circumferential direction and axial direction of the microtube, the pore size of the gas-liquid phase exchange holes 21 is in the range of 0.02mm-0.05mm, and the center distance between two adjacent gas-liquid phase exchange holes 21 in the axial direction of the microtube 2 is 0.05mm-0.1mm. The center distance between two adjacent gas-liquid phase exchange holes 21 in the circumferential direction of the microtube 2 is 0.05mm-0.1mm.

[0104] A large number of technical features are recorded in the specification of this application, which are distributed in various technical solutions. If all possible combinations of technical features of this application (i.e., technical solutions) are to be listed, the specification will be too long. In order to avoid this problem, the various technical features disclosed in the above-mentioned invention content of this application, the various technical features disclosed in the various embodiments and examples below, and the various technical features disclosed in the accompanying drawings can be freely combined with each other to form various new technical solutions (these technical solutions are all deemed to have been recorded in this specification), unless the combination of such technical features is technically infeasible. For example, in one example, feature A+B+C is disclosed, and in another example, feature A+B+D+E is disclosed, and features C and D are equivalent technical means that play the same role. Technically, only one can be used, and it is impossible to use them at the same time. Feature E can be combined with feature C technically. Then, the solution of A+B+C+D should not be deemed to have been recorded because it is technically infeasible, and the solution of A+B+C+E should be deemed to have been recorded.

[0105] All documents mentioned in this application are considered to be included in the disclosure of this application as a whole, so that they can be used as the basis for modification when necessary. In addition, it should be understood that after reading the above disclosure of this application, those skilled in the art can make various changes or modifications to this application, and these equivalent forms also fall within the scope of protection claimed in this application.

Claims

1. A device for preparing high-abundance argon isotopes using high-purity argon as a medium, characterized in that: include: n-stage cryogenic distillation equipment arranged in series, and a cascade pump (5) arranged between two adjacent stages of cryogenic distillation equipment, each stage of the cryogenic distillation equipment comprising a reboiler (3), a distillation unit (1) and a condenser (4), the raw material of the n-stage cryogenic distillation equipment being high-purity argon gas of natural abundance; Each distillation unit (1) comprises a heavy fraction end (11) and a light fraction end (12), and each distillation unit (1) is formed by stacking a plurality of microtubes (2). During the distillation process of the high-purity argon gas, the microtubes (2) are used to provide a liquid phase channel (200) for liquid flow, and the external space outside the microtubes (2) is configured to allow gas flow; When n≥2, the heavy fraction product obtained at the heavy fraction end of the previous stage distillation unit is input to the feed inlet of the next stage distillation unit through the cascade pump (5), and the light fraction product obtained at the light fraction end of the next stage distillation unit is condensed into liquid through the condenser and returned to the previous stage distillation unit for distillation. When the n-stage cryogenic distillation equipment is working, 40 Argon isotopes are enriched as heavy components at the heavy fraction end of the n-stage distillation unit and output.

2. The device according to claim 1, characterized in that The diameter of the microtube (2) is in the range of 0.3 mm to 1 mm, and a gas-liquid exchange hole (21) is provided on the wall of each microtube (2), so that during the distillation process of the high-purity argon gas, the liquid flows in the liquid phase channel (200) under the action of the capillary force of the microtube (2) and the surface tension of the gas-liquid exchange hole (21) and / or the gravity of the liquid, and the gas flows in the external space outside the microtube (2).

3. The device according to claim 2, characterized in that The heavy fraction enriched at the n-stage distillation unit of the n-stage cryogenic distillation equipment 40 The abundance of argon isotopes is greater than 99.99%.

4. The device according to claim 3, characterized in that The microtube (2) comprises a gas-liquid phase exchange section. When the gas in the external space and the liquid in the liquid phase channel (200) flow, heat and mass transfer are performed in the gas-liquid phase exchange section of the microtube (2) through the gas-liquid phase exchange holes, so that the heavy component gas in the external space is converted into liquid and enters the liquid phase channel (200), and the light component liquid in the liquid phase channel (200) is converted into gas and enters the external space, and separation and purification are achieved by repeated reciprocation.

5. The device according to claim 4, characterized in that During the distillation process, the plurality of microtubes (2) are placed horizontally or tilted, and the heavy fraction end (11) of the distillation unit (1) and the light fraction end (12) of the distillation unit are at substantially the same height level or at different height levels.

6. The device according to claim 5, characterized in that The plurality of microtubes (2) are stacked together to form a cylinder, and the distance between the centers of two adjacent microtubes (2) is within the range of 1 mm to 2 mm.

7. The device according to claim 6, characterized in that The pore diameter of the gas-liquid phase exchange hole (21) is in the range of 0.02 mm to 0.05 mm.

8. The device according to claim 7, characterized in that The gas-liquid phase exchange holes are evenly arranged in the circumferential direction and the axial direction of the microtube.

9. The device according to claim 8, characterized in that The capillary force should be greater than or equal to the gas-liquid phase pressure difference, which refers to the difference between the static pressure head of the liquid in the liquid phase channel (200) and the static pressure head of the gas flowing in the external space outside the microtube (2).

10. The device according to any one of claims 1 to 9, characterized in that: 36 Argon, 38 The argon isotope product is obtained as a light component at the first light fraction end of the first-stage distillation unit and output as a product.

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