A system for preparing high-abundance carbon-13 isotope

Abstract

The present application discloses a system for preparing high-abundance carbon-13 isotope, including: a carbon capture device, a CO2 purification device, and a microchannel rectification device. The carbon capture device is configured to capture CO2 from the raw gas to obtain a first CO2 mixture; the CO2 purification device is configured to purify and refine the first CO2 mixture to obtain ultra-high purity CO2; the microchannel rectification device includes one or more stages of cryogenic rectification equipment. Each stage of cryogenic rectification equipment includes a reboiler, a rectification unit, and a condenser. The rectification unit includes a heavy fraction end and a light fraction end. The one or more stages of cryogenic rectification equipment use ultra-high purity CO2 as the working medium, and enrich and output carbon-13 isotope carbon dioxide products at the heavy fraction end of the last stage of rectification unit. This system is an efficient separation device from carbon dioxide extraction to carbon purification and then to carbon-13 extraction, which improves the enrichment efficiency of carbon-13 and realizes the rational utilization of carbon dioxide and carbon isotopes.

Description

Technical Field

[0001] The present application relates to the technical field of isotope separation, and in particular to a system for preparing high-abundance carbon-13 isotopes. Background Art

[0002] Under the development trend of global carbon cycle and energy utilization, carbon dioxide (CO 2 ) is a major carbon source, and its recovery and utilization have important environmental and industrial value. Among them, carbon-13 (13C) is a stable carbon isotope, which is widely used in medicine, nuclear magnetic resonance (NMR) analysis, isotope tracing, biological metabolism research and climate change research. For example, in the field of Helicobacter pylori diagnosis, the urea breath test based on carbon-13 has completely replaced the carbon-14 detection method, fully verifying the significant safety advantages of carbon-13 labeled compounds in clinical applications. However, since the abundance of 13C in nature is only about 1.1%, its effective extraction and separation technology has become a research hotspot.

[0003] Carbon dioxide extraction typically involves capturing CO from industrial emissions, the atmosphere, natural gas fields, or biomass fermentation processes. 2 In the existing technology, physical absorption, chemical absorption, membrane separation and low-temperature condensation are mainly used. Among them, chemical absorption (such as amine absorbent) and membrane separation technology have become widely used technical solutions due to their high efficiency and adaptability. In this technical solution, multi-stage separation technology is used to improve the extraction efficiency of carbon dioxide and reduce the accompanying gases (such as N 2 , O 2 , H 2 O and CH 4 ) interference.

[0004] The extracted carbon dioxide often contains a variety of impurities, such as water vapor, sulfur oxides (SOx), nitrogen oxides (NOx), carbon monoxide (CO) and trace organic compounds, which will affect the subsequent separation of carbon isotopes. Therefore, purification technologies are needed, such as condensation drying, adsorbents (such as activated carbon, molecular sieves) to remove impurities, and catalytic oxidation to remove organic matter. In addition, chemical reaction methods (such as using alkaline solutions to remove acidic impurities) can also further improve CO 2 The purity of the material ensures its suitability for the extraction of carbon-13.

[0005] As isotope tracing technology develops towards precision, the demand for high-abundance carbon-13 isotopes (13C abundance > 99%) continues to grow. The current industrial production method for carbon-13 isotopes is cryogenic distillation, but the use of traditional distillation towers requires hundreds or even thousands of meters in height, and the distillation equipment is too large, making it very difficult to apply in actual engineering.

[0006] Therefore, there is an urgent need in this field to develop a system for preparing high-abundance carbon-13 isotopes. The system is an efficient separation equipment from carbon dioxide extraction to carbon purification and then to carbon-13 extraction, which improves the enrichment efficiency of carbon-13 and realizes the rational utilization of carbon dioxide and carbon isotopes. Summary of the invention

[0007] The purpose of this application is to provide a system for preparing high-abundance carbon-13 isotopes. The system is an efficient separation device from carbon dioxide extraction to carbon purification and then to carbon-13 extraction, so as to improve the enrichment efficiency of carbon-13 and realize the rational utilization of carbon dioxide and carbon isotopes.

[0008] The present application provides a system for preparing high-abundance carbon-13 isotopes, comprising:

[0009] A carbon capture device configured to capture CO from the feed gas 2 , thereby obtaining 2 The first CO 2 mixture;

[0010] CO 2 Purification device, the CO 2 The purification device is configured to 2 The mixture is purified and refined to obtain ultra-high purity CO 2 ;

[0011] A microchannel distillation device, the microchannel distillation device comprises one or more stages of cryogenic distillation equipment, each stage of cryogenic distillation equipment comprises a reboiler, a distillation unit and a condenser, the distillation unit comprises a heavy fraction end and a light fraction end, the one or more stages of cryogenic distillation equipment uses the ultra-high purity CO 2 as the working medium, and enriching and outputting the carbon-13 isotope carbon dioxide product at the heavy fraction end of the last-stage distillation unit of the one-stage or multi-stage cryogenic distillation equipment;

[0012] The distillation unit is formed by stacking a number of microchannel distillation tubes, the diameter of the microchannel distillation tubes is in the range of 0.3 mm to 1 mm, and a gas-liquid phase exchange hole is provided on the tube wall of each microchannel distillation tube so that the ultra-high purity CO to be distilled 2 During the distillation process, the microchannel distillation tube provides a liquid phase channel for liquid flow under the action of the capillary force of the microchannel distillation tube and the surface tension of the gas-liquid phase exchange hole, and the external space outside the microchannel distillation tube is configured for gas flow.

[0013] In another preferred embodiment, the raw gas is flue gas generated by the combustion of fossil fuels.

[0014] In another preferred embodiment, the first CO2 The mixture mainly includes impurities such as water, sulfide, nitrogen oxides, and particulate matter.

[0015] In another preferred embodiment, the CO 2 The purification device is configured to convert the first CO 2 CO in the mixture 2 Purity increased to 99.99%.

[0016] In another preferred embodiment, the CO 2 The purification device includes a cooler, a gas-liquid separator, a desulfurization treatment device, a denitrification treatment device, and a filter.

[0017] In another preferred embodiment, the cooler and the gas-liquid separator are used to separate the first CO 2 water in the mixture.

[0018] In another preferred embodiment, the total number of the microchannel distillation tubes is 100-200, so that a carbon dioxide product with a carbon-13 isotope abundance higher than 99% is enriched and outputted at the heavy fraction end of the last-stage distillation unit.

[0019] In another preferred example, the carbon capture device is a CCU carbon capture and utilization device.

[0020] In another preferred example, the CCU carbon capture and utilization device includes an absorption tower, a desorption tower, a lean liquid pump, a heat exchanger, and a throttle valve.

[0021] In another preferred embodiment, the distillation unit is placed horizontally, inclined, or vertically.

[0022] In another preferred embodiment, it further comprises a shell, and the distillation unit is arranged in the shell.

[0023] In another preferred embodiment, the distillation unit has a first end and a second end opposite to the first end. During the distillation process, the ultra-high purity CO to be distilled is condensed into liquid at the second end. 2 The ultra-high purity CO to be distilled, which is heated to gas at the first end, flows in the liquid phase channel along the first axial direction of the distillation unit under the capillary force of the microchannel distillation tube and the surface tension of the gas-liquid phase exchange hole. 2 Under the action of pressure difference, the external space outside the microchannel distillation tube moves along the second axial direction of the distillation unit, and the second axial direction is opposite to the first axial direction.

[0024] 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.

[0025] In another preferred example, the gas moves along the second axial direction, and the liquid moves along the first axial direction.

[0026] In another preferred example, the microchannel distillation tube 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 microchannel distillation tube 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.

[0027] In another preferred embodiment, the plurality of microchannel distillation tubes are placed horizontally or obliquely, 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.

[0028] In another preferred embodiment, the plurality of microchannel distillation tubes are stacked together to form a cylinder, and the distance between the centers of two adjacent microchannel distillation tubes is in the range of 1 mm to 2 mm.

[0029] In another preferred embodiment, the plurality of microchannel distillation tubes are stacked together to form a column, and the cross section of the column is circular.

[0030] In another preferred embodiment, the structures and sizes of the plurality of microchannel distillation tubes are the same.

[0031] In another preferred embodiment, the length of the microchannel distillation tube is in the range of 500 mm-1000 mm.

[0032] In another preferred embodiment, the pore size of the gas-liquid exchange hole is in the range of 0.02 mm-0.05 mm.

[0033] In another preferred embodiment, the gas-liquid phase exchange holes are evenly arranged in the circumferential direction and the axial direction of the microchannel distillation tube.

[0034] In another preferred embodiment, the center distance between two adjacent gas-liquid phase exchange holes in the circumferential direction of the microchannel distillation tube is 0.05 mm-0.1 mm.

[0035] 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 microchannel distillation tube.

[0036] In another preferred embodiment, the spacing between two adjacent gas-liquid phase exchange holes on the wall of the microchannel distillation tube with the same cross section of the microchannel distillation tube is 0.05 mm-0.1 mm.

[0037] In another preferred embodiment, the center distance between two adjacent gas-liquid phase exchange holes in the axial direction of the microchannel distillation tube is 0.05 mm-0.1 mm.

[0038] In another preferred example, when the microchannel distillation device includes a multi-stage cryogenic distillation device, a cascade pump is arranged between two adjacent stages of cryogenic distillation equipment, and 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, 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 multi-stage cryogenic distillation equipment is working, the carbon dioxide product with carbon-13 isotope is enriched and output as a heavy component at the heavy fraction end of the last stage distillation unit.

[0039] In another preferred embodiment, the one or more stages of cryogenic distillation equipment are connected in series.

[0040] In another preferred embodiment, 12 CO 2 The product is obtained as a light component at the light fraction end of the distillation unit and output as a product.

[0041] 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

[0042] 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.

[0043] Figure 1 is a schematic diagram of a system for preparing high-abundance carbon-13 isotopes according to the present application;

[0044] Figure 2 is a schematic structural diagram of a microchannel distillation device according to an embodiment of the present application;

[0045] Figure 3 is a schematic structural diagram of a distillation unit (housing not shown) of a microchannel distillation device according to the present application;

[0046] Figure 4 is a partial structural schematic diagram of a distillation unit of a microchannel distillation device according to the present application;

[0047] Figure 5 It is a schematic diagram of the structure of a microchannel distillation tube of a distillation unit of a microchannel distillation device according to the present application.

[0048] In the accompanying drawings, the following are marked:

[0049] 1-Distillation unit

[0050] 11-First End

[0051] 12-Second end

[0052] 2-Microchannel distillation tube

[0053] 21-Gas-liquid phase exchange hole

[0054] 200-Liquid Phase Channel

[0055] 3-Reboiler

[0056] 4-Condenser

[0057] 5-Cascade Pump DETAILED DESCRIPTION

[0058] Through extensive and in-depth research, the inventors have disclosed for the first time a system for preparing high-abundance carbon-13 isotopes. The system uses an efficient separation method from carbon dioxide extraction to carbon purification and then to carbon-13 extraction to improve the enrichment efficiency of carbon-13, realize the rational utilization of carbon dioxide and carbon isotopes, and increase CO 2 Added value: Compared with the traditional distillation tower, the capillary force-driven microchannel distillation device of the present application greatly reduces the space requirement in height when separating carbon dioxide from carbon-13, and has more practical engineering applications.

[0059] 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.

[0060] the term

[0061] 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.

[0062] As used herein, a "distillation process" is a process that achieves separation based on the differences in boiling points of different isotopes of carbon dioxide.

[0063] 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.

[0064] 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.

[0065] This application has at least one of the following advantages

[0066] (a) The present application provides a system for preparing high-abundance carbon-13 isotopes. The system is a combined device that combines a CCU device and a microchannel distillation device to produce high-purity CO 2 Used as a medium to separate and purify carbon-13 isotopes;

[0067] (b) The present application provides a system for preparing high-abundance carbon-13 isotopes, wherein CO 2 The carbon-13 isotope in the carbon is separated and purified for use, while the carbon-12 carbon dioxide product continues to be used for storage, which increases the CO 2 Added value;

[0068] (c) The size of the microchannel distillation device in the system for preparing high-abundance carbon-13 isotopes of the present application is much smaller than that of the traditional distillation tower, and has more practical engineering applications;

[0069] (d) The system for preparing high-abundance carbon-13 isotopes of the present application provides a distillation unit with an ingenious structure, which utilizes the combined effects of the capillary force and surface tension of the microchannel distillation tube and / or the gravity of the liquid to achieve a distillation process and improve separation efficiency;

[0070] (e) The distillation unit of the present application can achieve ultra-high purity CO by being placed horizontally or slightly tilted. 2 Compared with traditional distillation towers, separation and purification does not require space in the height direction and has more practical engineering applications.

[0071] 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.

[0072] A system for preparing high-abundance carbon-13 isotope

[0073] See also Figure 1 The present application provides a system for preparing high-abundance carbon-13 isotopes. The system is a system for preparing high-abundance carbon-13 isotopes in combination with CCU. The system includes a carbon capture device, a CO 2 Purification device and microchannel distillation device, the raw gas is passed into the carbon capture device for CO 2 Capture to obtain CO 2 The first CO 2 Mixture, first CO 2 The mixture includes impurities such as water, sulfide, nitrogen oxide, particulate matter, etc. 2 The purification device converts CO 2 The purity is increased to 99.99%, removing impurities such as water; ultra-high purity CO 2 It is sent to the microchannel distillation device for isotope purification, and finally an abundance of 99% is obtained. 13 CO 2 .

[0074] In one embodiment, the carbon capture device includes an absorption tower, a desorption tower, a lean liquid pump, a heat exchanger, a throttle valve and other devices. The process includes: flue gas pretreatment: the flue gas generated by the combustion of fossil fuels first enters the pretreatment unit to remove impurities such as particulate matter, sulfur dioxide, nitrogen oxides, etc., so as to prevent these impurities from interfering with the subsequent carbon dioxide capture process and reducing the efficiency and service life of the absorbent. For example, particulate matter is removed by an electrostatic precipitator, and sulfur dioxide is removed by a wet desulfurization process. Absorption process: the pretreated flue gas enters the absorption tower and is in countercurrent contact with the absorbent (commonly used absorbents include ethanolamine solutions, etc.). Carbon dioxide reacts chemically or physically adsorbs with the absorbent, and is thereby absorbed by the absorbent. Desorption process: the rich liquid (the absorbent that has absorbed carbon dioxide) flows out from the bottom of the absorption tower and enters the desorption tower. In the desorption tower, the carbon dioxide in the rich liquid is desorbed by heating, and the absorbent is regenerated. The desorbed carbon dioxide is cooled, compressed, and other processes before entering the CO 2 Purification device, the regenerated absorbent is returned to the absorption tower for recycling.

[0075] Among them, CO 2 The purification device includes a cooler, a gas-liquid separator mainly used to separate liquid water, a desulfurization treatment device, a denitrification treatment device, a filter and other devices, CO 2 The purification device is used to convert the first CO obtained by the carbon capture device 2 The mixture is purified and refined to obtain ultra-high purity CO with a purity of 99.99% 2 Among them, the first CO 2 The mixture includes impurities such as moisture, sulfide, nitrogen oxides, particulate matter, CO 2 The purification device may be any device used in conventional technology that can 2 The mixture is purified to CO 2 The purity of the device is 99.99%.

[0076] The microchannel distillation device (MCD) includes a reboiler 3, a distillation unit 1 and a condenser 4. 2 As the working medium, it is introduced into the microchannel distillation tube 2, and the CO is distilled by the capillary force of the microchannel distillation tube 2. 2 Multi-channel single-stage separation is performed to obtain concentrated / depleted carbon isotopes. The microchannel distillation device will be described in detail below;

[0077] Among them, the ultra-high purity CO to be distilled 2 As the working medium, it is introduced into the microchannel distillation device MCD, and the carbon dioxide is separated into multiple channels and single stages by capillary force using cryogenic distillation method to obtain concentrated / depleted carbon isotopes, including: 2 Enter the microchannel distillation device, CO2 Binary components with different relative molecular masses will form different distributions in the temperature field. The light component 12 CO 2 is heated and evaporated first in the reboiler 3, and the heavy component 13 CO 2 is first condensed when it meets cold in the condenser 4. The gas-liquid two-phase conducts heat and mass transfer through multiple channels, and the heavy components gradually gather, thus realizing the separation of heavy components and light components.

[0078] Microchannel distillation device (MCD device)

[0079] The present application provides a microchannel distillation device, which includes one or more stages of cryogenic distillation equipment. The cryogenic distillation equipment includes: a distillation unit 1 and a housing (not shown), a reboiler 3 and a condenser 4.

[0080] See Figure 3-5 , the distillation unit 1 is arranged inside the housing. The distillation unit 1 is formed by stacking a plurality of microchannel distillation tubes 2 together; the diameter of the microchannel distillation tube 2 is in the range of 0.3 mm - 1 mm, and gas-liquid exchange holes 21 are provided on the tube wall of each microchannel distillation tube 2, so that in the distillation process of ultra-high purity CO to be distilled 2 , under the action of the capillary force of the microchannel distillation tube 2 and the surface tension of the gas-liquid exchange holes 21, the microchannel distillation tube 2 provides a liquid phase channel 200 for liquid flow, and the external space outside the microchannel distillation tube 2 is configured for gas flow; preferably, a plurality of microchannel distillation tubes 2 are stacked together to form a cylinder, and the center distance between adjacent two microchannel distillation tubes 2 is in the range of 1 mm - 2 mm.

[0081] The distillation unit 1 has a first end 11 (i.e., the heavy fraction end) and a second end 12 (i.e., the light fraction end) opposite to the first end 11. The first end 11 and the second end 12 of the microchannel distillation tube are fixed with 2 sieve trays respectively. During the distillation process, the ultra-high purity CO to be distilled that is condensed into liquid at the second end 12 2 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 microchannel distillation tube 2 and the surface tension of the gas-liquid exchange holes 21, and the CO to be distilled that is heated into gas at the first end 11 2 moves in the external space outside the microchannel distillation tube 2 along the second axial direction of the distillation unit 1 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. The first axial direction is the direction from the second end 12 to the first end 11, and the second axial direction is the direction from the first end 11 to the second end 12.

[0082] Specifically, the condenser 4 is located at the second end 12 of the distillation unit 1 and is configured to convert the heavy components of the ultra-high purity carbon dioxide to be distilled into a gaseous state. 13 CO 2 The reboiler 3 is located at the first end 11 of the distillation unit 1 and is configured to condense the light components in the ultra-high purity carbon dioxide to be distilled into liquid. 12 CO 2 When the distillation starts, the gas is cooled and liquefied into liquid by the condenser 4 located at the second end 12. The liquid flows downward in the microchannel distillation tube 2 to the first end 11 of the distillation unit 1 by gravity (when the distillation unit 1 is tilted) and capillary force. The light components in the liquid at the first end 11 12 CO 2 The gas is heated by the reboiler 3 and flows toward the second end 12 (along the second axial direction) outside the microchannel distillation tube 2 by pressure difference to reach the second end 12. During the gas-liquid flow process, the heavy components are brought to the liquid phase and the light components are brought to the gas phase through the gas-liquid phase exchange hole 21 for heat and mass transfer, and separation and purification are achieved by repeated reciprocation. The liquid at the first end 11 can be used for continuous condensation or collected to become the carbon dioxide product of the device for storage.

[0083] The microchannel distillation tube 2 includes a gas-liquid phase exchange section, and the gas-liquid phase exchange section of the microchannel distillation tube 2 is a part of the microchannel distillation tube 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 phase exchange section of the microchannel distillation tube 2 through the gas-liquid phase 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 openings (gas-liquid phase exchange holes 21) on the tube wall are gas-liquid phase exchange interfaces, which facilitate heat and mass transfer between gas and liquid phases. 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 openings.

[0084] In one embodiment, for example, when the microchannel distillation device includes a multi-stage cryogenic distillation device, see Figure 2 , Figure 2 A method for implementing a microchannel distillation device is shown. Figure 2 FIG. 1 shows a plurality of cryogenic distillation devices arranged in series, with a cascade pump 5 provided between two adjacent cryogenic distillation devices. The heavy fraction product obtained at the heavy fraction end of the previous distillation unit 13 CO 2 The cascade pump is then fed to the feed inlet of the next distillation unit, and the light fraction product obtained at the light fraction end of the next distillation unit is 12 CO 2After being condensed into liquid by the condenser 4, it is returned to the previous distillation unit for distillation. When the multi-stage cryogenic distillation equipment is working, the carbon dioxide product with carbon-13 isotope ( 13 CO 2 ) is enriched and outputted as a heavy component at the heavy fraction end of the last stage of the distillation unit. Preferably, the total number of microchannel distillation tubes 2 of all cryogenic distillation equipment is between 100 and 200, which can achieve a carbon dioxide product with a carbon-13 isotope abundance higher than 99%.

[0085] In other embodiments, the microchannel distillation device includes a cryogenic distillation equipment, wherein the cryogenic distillation equipment may include a distillation unit 1, and the number of microchannel distillation tubes 2 of the distillation unit 1 is between 100-200, or the cryogenic distillation equipment may include multiple distillation units 1, and the cryogenic distillation equipment is composed of multiple distillation units 1 in series and parallel, that is, multiple distillation units 1 are connected in parallel to form a separation unit, and multiple separation units are connected in series to form the cryogenic distillation equipment, wherein the number of microchannel distillation tubes 2 is between 100-200.

[0086] In one embodiment, a plurality of microchannel distillation tubes 2 are placed horizontally or tilted on a horizontal plane, that is, the distillation unit 1 is placed horizontally or slightly tilted on a horizontal plane. Distillation is achieved by placing the distillation unit horizontally or tilted. Compared with a traditional vertically placed distillation tower, the space requirement for height is low and it has more practical application value. The first end 11 of the distillation unit 1 and the second end 12 of the distillation unit are at the same height level or different height levels (in the case of tilted placement). In one embodiment, the tilt angle of the tilted placement can be 0-45 degrees. In one embodiment, when a plurality of microchannel distillation tubes 2 are placed horizontally on a horizontal plane, the first axial direction and the second axial direction are parallel to the horizontal plane.

[0087] In one embodiment, as required, the length of the microchannel distillation tube 2 is in the range of 500 mm-1000 mm.

[0088] In the present application, in order to achieve the desired gas-liquid mass transfer efficiency, a microchannel distillation tube 2 composed of uniform openings is constructed. By adjusting the spacing and pore size between the openings, the permeability between the microchannel distillation tubes 2 can be freely set. Based on the effective medium approximation theory (EMA), on a scale much larger than the opening spacing, such a microchannel distillation tube 2 can be considered to be uniform, isotropic, and have a constant effective permeability.

[0089] In the microchannel distillation tube 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.

[0090] 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 microchannel distillation tube 2). This requires that the size and structure of the liquid phase channel 200 of the microchannel distillation tube be properly designed so that the liquid can flow stably in the microchannel.

[0091] 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 microchannel distillation tubes 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.

[0092] 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.

[0093] The gas-liquid phase pressure difference ΔP is the difference between the liquid static pressure head and the vapor static pressure head:

[0094]

[0095] in, and are the liquid and vapor densities, respectively, in kg / m³, g is the acceleration due to gravity, in m / s², and h is the height of the liquid column, i.e., the height of the liquid in the diameter direction of the microchannel distillation tube, in m.

[0096] The pressure difference due to capillary force is calculated as follows:

[0097]

[0098] in, is the tension coefficient of the liquid in the microchannel distillation tube, in N / m, and R is the size of the gas-liquid phase exchange hole 21 on the tube wall, in radius, in m.

[0099] Therefore, in the design of the microchannel distillation tube 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 microchannel distillation tube 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 microchannel distillation tube, 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 microchannel distillation tube 2 is 0.05mm-0.1mm. The center distance between two adjacent gas-liquid phase exchange holes 21 in the circumferential direction of the microchannel distillation tube 2 is 0.05mm-0.1mm.

[0100] The specification of this application records a large number of technical features, which are distributed in various technical solutions. If all possible combinations of technical features (i.e., technical solutions) of this application are listed, the specification will be too long. In order to avoid this problem, the various technical features disclosed in the above 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 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 such a combination of 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. Features C and D are equivalent technical means that play the same role. Technically, only one of them 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, while the solution of A+B+C+E should be deemed to have been recorded.

[0101] 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 system for preparing high-abundance carbon-13 isotopes, characterized in that: include: a carbon capture device configured to capture CO2 from the raw gas to obtain a first CO2 mixture containing CO2; A CO2 purification device, wherein the CO2 purification device is configured to purify and refine the first CO2 mixture to obtain ultra-high purity CO2; A microchannel distillation device, the microchannel distillation device comprising one or more 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 distillation unit comprising a heavy fraction end and a light fraction end, the one or more stages of cryogenic distillation equipment using the ultra-high purity CO2 as a working medium, and enriching and outputting a carbon-13 isotope carbon dioxide product at the heavy fraction end of the last stage of the distillation unit of the one or more stages of cryogenic distillation equipment; The distillation unit (1) is formed by stacking a plurality of microchannel distillation tubes (2), the diameter of the microchannel distillation tubes (2) being in the range of 0.3 mm to 1 mm, and a gas-liquid phase exchange hole (21) is provided on the tube wall of each microchannel distillation tube (2), so that during the distillation process of the ultra-high purity CO2 to be distilled, under the action of the capillary force of the microchannel distillation tube (2) and the surface tension of the gas-liquid phase exchange hole (21), the microchannel distillation tube (2) provides a liquid phase channel (200) for liquid flow, and the external space outside the microchannel distillation tube (2) is configured to allow gas flow.

2. The system according to claim 1, characterized in that The CO 2 purification device is configured to increase the purity of CO 2 in the first CO 2 mixture to 99.99%.

3. The system according to claim 1, characterized in that The total number of the microchannel distillation tubes (2) is between 100 and 200, thereby enriching and outputting a carbon dioxide product with a carbon-13 isotope abundance higher than 99% at the heavy fraction end of the last stage distillation unit.

4. The system according to claim 1, characterized in that The carbon capture device is a CCU carbon capture and utilization device.

5. The system according to claim 1, wherein: The microchannel distillation tube (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 microchannel distillation tube (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.

6. The system according to claim 5, characterized in that The plurality of microchannel distillation tubes (2) are placed horizontally or obliquely, and the heavy fraction end of the distillation unit (1) and the light fraction end of the distillation unit are at substantially the same height level or at different height levels.

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

8. The system 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 microchannel rectification tube (2).

9. The system according to claim 8, characterized in that 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 (200) and the static pressure head of the gas flowing in the external space outside the microchannel distillation tube (2).

10. The system according to claim 1, wherein: When the microchannel distillation device includes a multi-stage cryogenic distillation device, a cascade pump is arranged between two adjacent stages of cryogenic distillation equipment, and 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, 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 multi-stage cryogenic distillation equipment is working, the carbon dioxide product with carbon-13 isotope is enriched and output as a heavy component at the heavy fraction end of the last stage distillation unit.

Images