Low-temperature rectification system and low-temperature rectification method

Abstract

The embodiment of the invention relates to the technical field of low-temperature rectification, in particular to a low-temperature rectification system and a low-temperature rectification method.The system comprises a condensation part used for conducting gas-liquid separation on tower top process materials and conveying liquid materials to a reboiling part, and steam is conveyed to a first heat regeneration part; the first heat regeneration part and the second heat regeneration part are used for heating the steam to a preset temperature; the compression assembly is used for compressing steam and conveying the steam to the reboiling part and the first heat exchange part; the reboiling part is used for heating the liquid material to gasify the liquid material and conveying the gas material to the condensing part; the first heat exchange piece is used for heat exchange of steam; the first heat exchange piece and the reboiling piece are used for conveying liquid materials into the first heat return piece to be cooled, and the circulation driving piece is used for circulating the materials to the condensation piece. According to the low-temperature rectification system, heat can be provided for the reboiling part, the energy consumption of the reboiling part is reduced, cold energy can be provided for the condensation part, the energy consumption of the condensation part is reduced, and then the energy consumption of the whole low-temperature rectification system is reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of cryogenic distillation technology, and in particular to a cryogenic distillation system and a cryogenic distillation method. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] Cryogenic distillation is a process that exploits the differences in boiling points and saturated vapor pressures of components in a mixture at specific temperatures, allowing the components to be separated at different temperatures. By controlling the temperature and pressure during the distillation process, different components in the mixture can be caused to evaporate and condense at different rates, thereby achieving separation of the components.

[0004] Currently, cryogenic distillation is widely used in a variety of fields, including isotope separation, industrial gas separation and purification, hydrogen recovery, and oxygen extraction in the gas separation field; separation and purification in the petroleum, chemical, and pharmaceutical industries in the liquid separation field; and purification and concentration of fruit juices and alcoholic beverages in the food industry. However, current cryogenic distillation processes still have many shortcomings. Summary of the Invention

[0005] A brief overview of the present application is provided below to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify key or important portions of the present application, nor is it intended to limit the scope of the present application. Its purpose is simply to present certain concepts in a simplified form as a prelude to the more detailed description that will be discussed later.

[0006] In the first aspect, an embodiment of the present application provides a cryogenic distillation system, which is suitable for cryogenic distillation of process materials, and includes a condensing element, a first heat recovery element, a second heat recovery element, a compression component, a reboiler element, a circulation drive element and a first heat exchange element. The condensing element is configured to perform gas-liquid separation on the process material at the top of the tower to obtain liquid material, and is configured to transport the liquid material to the reboiler element, and to transport the vapor at the top of the tower to the first heat recovery element; the first heat recovery element is configured to initially heat the vapor; the second heat recovery element is configured to heat the vapor again until the vapor reaches a predetermined temperature; the compression element The component is configured to compress the vapor of a predetermined temperature and then transport it to the reboiling element and the first heat exchange element; the reboiling element is configured to heat the liquid material to vaporize the liquid material to form a gas material, and to liquefy the vapor to form a liquid material, and transport the gas material to the condensing element; the first heat exchange element is configured to at least exchange heat with the vapor of a predetermined temperature; the first heat exchange element and the reboiling element are also configured to transport the liquid material to the first heat recovery element for cooling, so that the first heat recovery element transports the cooled part of the liquid material to the circulation drive element; the circulation drive element is configured to circulate the liquid material to the condensing element.

[0007] The cryogenic distillation system provided in the embodiment of the present application heats the vapor at the top of the tower in sequence through the first heat recovery element, the second heat recovery element and the compression assembly, and then transports the heated vapor to the reboiling element, which can provide heat for the reboiling element, thereby reducing the energy consumption of the reboiling element. Part of the liquid material flowing out of the reboiling element and the first heat exchange element is circulated back to the condensing element through the first heat recovery element and the circulation drive element, so that the liquid material can absorb the heat of the vapor in the condensing element, thereby achieving the purpose of providing cooling capacity for the condensing element, which is beneficial to reducing the energy consumption of the condensing element, and further reducing the energy consumption of the entire cryogenic distillation system.

[0008] In a second aspect, an embodiment of the present application further provides a cryogenic distillation method, which is applicable to the cryogenic distillation system of the embodiment of the present application, and the method comprises the following steps: S1, pre-cooling the condensing element of the cryogenic distillation system, and using the first heat exchange element of the cryogenic distillation system for heat exchange; S2, during the cryogenic distillation process, using the condensing element to separate the process material at the top of the tower into gas and liquid, and conveying the separated liquid material to the reboiling element of the cryogenic distillation system, and conveying the vapor at the top of the tower to the first heat recovery element of the cryogenic distillation system; S3, using the first heat recovery element to initially heat the vapor flowing out of the condensing element, and then using the second heat recovery element of the cryogenic distillation system to heat the vapor again until the vapor reaches a predetermined temperature; S4, conveying the vapor at the predetermined temperature to the compression component of the cryogenic distillation system, and compressing the vapor using the compression component; S5, conveying the compressed vapor to the reboiling element and the first heat exchange element; S6, heating the liquid material in the reboiling element to vaporize the liquid material to form a gas material, and conveying the gas material to the condensing element;

[0009] S7. The liquefied material in the reboiling part and the liquefied material after heat exchange in the first heat exchange part are transported to the first heat recovery part for cooling, so that the first heat recovery part can transport the cooled partially liquid material to the circulation drive part of the low-temperature distillation system; S8. The liquid material is circulated and driven to the condensing part by the circulation drive part.

[0010] These and other advantages of the present application will become more apparent through the following detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] To further illustrate the above and other advantages and features of the present application, the following detailed description of specific embodiments of the present application is provided in conjunction with the accompanying drawings. The accompanying drawings, together with the detailed description below, are incorporated into and form a part of this specification. Elements with the same function and structure are denoted by the same reference numerals. It should be understood that these drawings depict only typical examples of the present application and should not be construed as limiting the scope of the present application.

[0012] Figure 1 is a structural schematic diagram of a cryogenic distillation system according to the first embodiment of the present application;

[0013] Figure 2 is a schematic structural diagram of a cryogenic distillation system according to a second embodiment of the present application;

[0014] Figure 3 is a schematic structural diagram of a cryogenic distillation system according to a third embodiment of the present application;

[0015] Figure 4 is a schematic structural diagram of a cryogenic distillation system according to a fourth embodiment of the present application;

[0016] Figure 5 It is a schematic flow chart of a cryogenic distillation method according to an embodiment of the present application.

[0017] It should be noted that the drawings are not necessarily drawn to scale, but are merely shown in a schematic manner that does not affect the reader's understanding.

[0018] Description of reference numerals:

[0019] 10. Condensation element; 21. First heat recovery element; 22. Second heat recovery element; 23. Compression assembly; 231. Compression element; 232. First flow control element; 30. Reboiler element; 40. Circulation drive element; 41. Expansion element; 42. Drive element; 50. First heat exchange element; 61. Working fluid storage element; 62. Second heat exchange element; 631. First control unit; 632. Second control unit; 64. Third flow control element; 711. First tower body; 712. Second tower body; 72. Isolation element. DETAILED DESCRIPTION

[0020] Hereinafter, exemplary embodiments of the present application will be described with reference to the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual implementation are described in the specification. However, it should be understood that in the process of developing any such actual implementation, many implementation-specific decisions must be made in order to achieve the developer's specific goals, such as meeting those constraints related to the system and business, and these constraints may vary from implementation to implementation. In addition, it should be understood that although the development work may be very complex and time-consuming, it is a routine task for those skilled in the art who benefit from the content of this application.

[0021] It is also necessary to point out here that, in order to avoid obscuring the present application due to unnecessary details, the accompanying drawings only show the device structure and / or processing steps that are closely related to the solution according to the present application, while other details that are not closely related to the present application are omitted.

[0022] It should be noted that, unless otherwise defined, the technical or scientific terms used in this application should have the common meanings understood by persons having ordinary skills in the field to which this application belongs.

[0023] In the description of the embodiments of the present application, “multiple” means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0024] The cryogenic distillation process in related art is primarily implemented using a cryogenic distillation system, which includes a condenser, a distillation column, and a reboiler. Typically, the cooling capacity of the condenser is provided by a refrigeration system, while the heating capacity of the reboiler is provided by an electric heater. However, when the distillation temperature falls below a certain level, the condenser consumes a large amount of energy to generate cooling capacity, and the lower the distillation temperature, the greater the energy consumption of the condenser.

[0025] In response to the above technical problems, an embodiment of the present application provides a cryogenic distillation system, which is suitable for cryogenic distillation of process materials. Figure 1 The structural diagram of the cryogenic distillation system according to the first embodiment of the present application is as follows: Figure 1As shown, the cryogenic distillation system at least includes a condensing element 10, a first heat recovery element 21, a second heat recovery element 22, a compression assembly 23, a reboiling element 30, a circulation drive element 40 and a first heat exchange element 50. The condensing element 10 is configured to perform gas-liquid separation on the process material at the top of the tower to obtain liquid material, and is configured to transport the liquid material to the reboiling element 30, and to transport the vapor at the top of the tower to the first heat recovery element 21; the first heat recovery element 21 is configured to initially heat the vapor; the second heat recovery element 22 is configured to heat the vapor again until the vapor reaches a predetermined temperature; the compression assembly 23 is configured to compress the vapor at a predetermined temperature and then transport it to the reboiling element 30 and the first heat exchange element 50; the reboiling element 30 is configured to heat the liquid material Heating is performed to vaporize the liquid material to form a gas material, and to liquefy the vapor to form a liquid material, and the gas material is transported to the condensing part 10; the first heat exchange part 50 is configured to exchange heat with at least the vapor of a predetermined temperature; the first heat exchange part 50 and the reboiler part 30 are also configured to transport the liquid material to the first heat recovery part 21 for cooling, so that the first heat recovery part 21 transports the cooled part of the liquid material to the circulation drive part 40; the circulation drive part 40 is configured to circulate and drive the liquid material to the condensing part 10.

[0026] The cryogenic distillation system provided in the embodiment of the present application heats the vapor at the top of the tower in sequence through the first heat recovery component 21, the second heat recovery component 22 and the compression assembly 23, and then transports the heated vapor to the reboiler component 30, which can provide heat for the reboiler component 30, thereby reducing the energy consumption of the reboiler component 30. Part of the liquid material flowing out of the reboiler component 30 and the first heat exchange component 50 is circulated back to the condenser component 10 through the first heat recovery component 21 and the circulation drive component 40, so that the liquid material can absorb the heat of the vapor in the condenser component 10, thereby achieving the purpose of providing cooling capacity for the condenser component 10, which is beneficial to reducing the energy consumption of the condenser component 10, and further reducing the energy consumption of the entire cryogenic distillation system.

[0027] In some embodiments, the cryogenic distillation system may further include a distillation tower, wherein the condensing element 10 is disposed at the top of the distillation tower, and the reboiling element 30 is disposed at the bottom of the distillation tower, and the condensing element 10 and the reboiling element 30 are connected through the tower body of the distillation tower.

[0028] In some embodiments, the cryogenic distillation system of the embodiments of the present application can be used to perform isotopic cryogenic distillation on process materials containing carbon monoxide, methane, nitric oxide, nitrogen, boron trifluoride, oxygen, hydrogen, helium, neon, xenon, krypton, argon and other substances. The present application does not limit the specific use of the cryogenic distillation system.

[0029] In some embodiments, when the cryogenic distillation system is initially started, the refrigeration system can be used to pre-cool the condensing element 10. At this time, in the process of the liquefied material entering the reboiling element 30 through the tower body, the liquid material is absorbed by the adsorption material in the tower body, and there is no liquid level in the reboiling element 30. All heat is taken away by the first heat exchange element 50.

[0030] In some embodiments, since the temperature of the air inhaled by the compression component 23 is limited, if the temperature is low, the compression component 23 will be difficult to operate normally. Therefore, the first heat recovery component 21 and the second heat recovery component 22 are used to heat the steam at the top of the tower to a predetermined temperature, and then the steam at the predetermined temperature is transported to the compression component 23 to ensure that the compression component 23 can operate normally.

[0031] In some embodiments, after the heated and compressed steam is transported to the reboiler 30, it can provide heat to the reboiler 30, causing the liquid material in the reboiler 30 to evaporate into gaseous material. During the evaporation process, the steam releases heat and liquefies into liquid material.

[0032] In some embodiments, when the height difference between the condensation element 10 and the compression assembly 23 is greater than or equal to a preset height difference, the circulation drive element 40 includes an expansion element 41 and a drive element 42. The expansion element 41 is connected to the first heat recovery element 21 and is configured to expand the cooled liquid material to reduce the pressure of the liquid material; the drive element 42 is connected to the expansion element 41 and the condensation element 10 respectively, and is configured to drive the liquid material in the expansion element 41 into the condensation element 10.

[0033] The cryogenic distillation system provided by the embodiment of the present application, when the height difference between the condensing element 10 and the compression assembly 23 is greater than or equal to the preset height difference, expands the cooled liquid material by setting an expansion element 41 to reduce the pressure of the liquid material, and then drives the liquid material back to the condensing element 10 by using the driving element 42. This ensures that the liquid material can circulate in the cryogenic distillation system to provide cooling for the condensing element 10 during the circulation process, and provides heat for the reboiling element 30 when evaporated into gas, thereby achieving the purpose of reducing the energy consumption of the entire cryogenic distillation system.

[0034] In some embodiments, the expansion member 41 may be any component with an expansion function, such as a throttle valve, a turbine expander, etc., and this application does not impose any limitation on this.

[0035] In some embodiments, the driving member 42 may be a circulation pump.

[0036] In some embodiments, when the height difference between the condensation element 10 and the compression assembly 23 is less than a preset height difference, the circulation drive element 40 is an expansion element 41, and the expansion element 41 is connected to the first heat recovery element 21 and the condensation element 10 respectively, and is configured to expand the cooled liquid material to reduce the pressure of the liquid material, and is configured to transport the expanded liquid material to the condensation element 10.

[0037] The cryogenic distillation system provided by the embodiment of the present application, when the height difference between the condensing element 10 and the compression assembly 23 is less than the preset height difference, expands the cooled liquid material by setting an expansion element 41, which is beneficial to reducing the pressure of the liquid material. Then, the purpose of circulating the liquid material to the condensing element 10 can be achieved without the need for additional driving components. In this way, the liquid material can be ensured to circulate in the cryogenic distillation system to provide cooling for the condensing element 10 and heat for the reboiling element 30 during the circulation process, thereby achieving the purpose of reducing the energy consumption of the entire cryogenic distillation system and simplifying the structure of the cryogenic distillation system.

[0038] In some embodiments, the condensation element 10, the first heat recovery element 21, the second heat recovery element 22 and the compression assembly 23 are connected in sequence so that the steam in the condensation element 10 can directly and promptly enter the first heat recovery element 21, the second heat recovery element 22 and the compression assembly 23 in sequence.

[0039] In some embodiments, the compression assembly 23 includes a compression element 231 and a first flow control element 232 . The compression element 231 is connected to the reboiler 30 and the first heat exchange element 50 via the first flow control element 232 . The compression element 231 is also connected to the second heat recovery element 22 .

[0040] The cryogenic distillation system provided in the embodiment of the present application utilizes the first flow control element 232 to control the connection between the compression element 231 and the reboiler element 30 and the first heat exchange element 50, respectively, for easy control.

[0041] In some embodiments, the first flow control element 232 is configured to control the compression element 231 to be in communication with the reboiler 30 and to be disconnected from the first heat exchange element 50 when the power of the reboiler 30 matches the condenser 10 .

[0042] In the cryogenic distillation system provided by the embodiment of the present application, when the power of the reboiler 30 matches the condenser 10, the compressor 231 delivers the heated and compressed steam to the reboiler 30, thereby providing heat to the reboiler 30 without the need for additional heat dissipation.

[0043] In some embodiments, after pre-cooling to a liquid level in the reboiler element 30, the power of the reboiler element 30 begins to gradually increase. When the power of the reboiler element 30 increases to match the power of the condenser element 10, the entire cryogenic distillation system can reach a stable equilibrium, thereby entering a stable distillation process. During the distillation process, the liquid material in the condenser element 10 absorbs heat from the overhead vapor, evaporating into gas, which then enters the first reheat element 21.

[0044] In some embodiments, when the power of the reboiler 30 increases to match the power of the condenser 10 , the sum of the powers of the condenser 10 and the compressor 231 is equal to the power of the reboiler 30 , and the first heat exchange element 50 does not work.

[0045] In some embodiments, the first flow control element 232 is further configured to control the compression element 231 to be in communication with the reboiler element 30 and the first heat exchange element 50 respectively when the power of the reboiler element 30 does not match the condenser element 10 .

[0046] In the cryogenic distillation system provided by the embodiment of the present application, when the power of the reboiler 30 does not match the condenser 10, the compressor 231 transports the heated and compressed steam to the reboiler 30 and the first heat exchanger 50, and uses the first heat exchanger 50 to take away excess heat, which is beneficial to ensure the stable operation of the cryogenic distillation system.

[0047] In some embodiments, when the power of the reboiler 30 does not match the power of the condenser 10 , the sum of the powers of the condenser 10 and the compressor 231 is equal to the sum of the powers of the reboiler 30 and the first heat exchanger 50 .

[0048] In some embodiments, the first heat recovery element 21 is further connected to the expansion element 41 for conveying the liquid material to the expansion element 41 so as to utilize the first heat recovery element 21 to cool the liquid material.

[0049] In some embodiments, the liquefied material in the reboiler 30 and the material after heat exchange in the first heat exchange element 50 may be transported to the first heat recovery element 21 for cooling, and then the cooled material may be transported to the expansion element 41 .

[0050] In some embodiments, the liquefied material in the reboiler 30 and the material that has undergone heat exchange in the first heat exchange element 50 can be transported to the first heat recovery element 21 for cooling. At the same time, the first heat recovery element 21 can also heat the steam coming out of the condensation element 10 to a temperature that allows it to enter the compression element 231. The first heat recovery element 21 can also recover part of the cooling capacity of the steam coming out of the condensation element 10.

[0051] In some embodiments, the cryogenic distillation system further includes an emergency component configured to provide emergency refrigerant to the condensing unit 10 in the event of a failure.

[0052] The cryogenic distillation system provided in the embodiment of the present application can provide emergency cooling capacity for the condensation unit 10 under fault conditions by setting up emergency components, thereby ensuring that the entire cryogenic distillation system can maintain stable operation under fault conditions, continuously providing liquid refrigerant to the condensation unit 10, thereby keeping the steam in the condensation unit 10 in a condensed state, avoiding the distillation system from being over-pressurized due to the reheating of the liquid material to form gas, and the phenomenon of steam extraction destroying the distillation balance, thereby improving the reliability of the operation of the cryogenic distillation system.

[0053] In some embodiments, the refrigerant may include, but is not limited to, carbon tetrafluoride, ethylene, or liquefied natural gas (LNG). In such embodiments, the type of refrigerant may be determined based on the operating temperature range of the cryogenic distillation system.

[0054] In some embodiments, Figure 2 is a structural diagram of a cryogenic distillation system according to a second embodiment of the present application, as shown in FIG. Figure 2 As shown, the emergency component includes: a working fluid storage component 61, a second heat exchange component 62 and a second flow control component. The second flow control component is configured to control the steam in the condensing component 10 to enter the first heat recovery component 21 under normal operating conditions, and the steam does not enter the second heat exchange component 62; the second flow control component is also configured to control the steam in the condensing component 10 to enter the second heat exchange component 62 under fault conditions, and the steam does not enter the first heat recovery component 21; the working fluid storage component 61 is configured to provide refrigerant to the second heat exchange component 62 under fault conditions to condense the steam in the second heat exchange component 62.

[0055] The low-temperature distillation system provided in the embodiment of the present application uses a second flow control element to control whether the condensing element 10 is connected to the first heat recovery element 21 and the second heat exchange element 62 or not, and can timely control the flow direction of the steam in the condensing element 10, thereby timely controlling the steam to enter the second heat exchange element 62 for heat exchange under a fault condition, and then circulate to the condensing element 10, thereby achieving the purpose of providing emergency cooling capacity for the condensing element 10.

[0056] In some embodiments, the second flow control element is configured to connect the condensing element 10 to the second heat exchange element 62 and the first heat recovery element 21 respectively, so that the control response is relatively timely.

[0057] In some embodiments, the second flow control element may include a first control part 631 and a second control part 632 , the condensing element 10 is connected to the first heat recovery element 21 via the first control part 631 , and the condensing element 10 is connected to the second heat exchange element 62 via the second control part 632 .

[0058] In other embodiments, the second flow control component may be a three-way valve, and the condensing component 10 is connected to the second heat exchange component 62 and the first heat recovery component 21 respectively via the second flow control component.

[0059] In some embodiments, the second flow control element is configured to control the condensation element 10 to be connected to the first heat recovery element 21 under normal operating conditions, and the condensation element 10 to be disconnected from the second heat exchange element 62, so that the steam in the condensation element 10 can enter the first heat recovery element 21, thereby realizing circulation in the entire cryogenic distillation system, ensuring that the cryogenic distillation system can operate stably under normal operating conditions.

[0060] In some embodiments, under normal operating conditions, the first control unit 631 is set to open and the second control unit 632 is set to closed, so that the condensation element 10 is connected to the first heat recovery element 21 and the condensation element 10 is not connected to the second heat exchange element 62.

[0061] In some embodiments, the second flow control element is configured to control the condensing element 10 to be connected to the second heat exchange element 62 under a fault condition, and the condensing element 10 to be disconnected from the first heat recovery element 21, further ensuring that the cryogenic distillation system can remain stable under a fault condition.

[0062] In some embodiments, under a fault condition, the first control unit 631 is set to closed and the second control unit 632 is set to open, so that the condensing element 10 is connected to the second heat exchange element 62 and the condensing element 10 is not connected to the first heat recovery element 21.

[0063] In some embodiments, the emergency component also includes a third flow control component 64, which is respectively connected to the working fluid storage component 61 and the second heat exchange component 62, so as to facilitate the use of the third flow control component 64 to control the connection or disconnection between the working fluid storage component 61 and the second heat exchange component 62, and timely control the flow direction of the emergency refrigerant stored in the working fluid storage component 61.

[0064] In some embodiments, the third flow control element 64 is configured to control the emergency refrigerant in the refrigerant storage element 61 from entering the second heat exchange element 62 under normal working conditions.

[0065] In some embodiments, the third flow control element 64 is configured to control the emergency refrigerant in the refrigerant storage element 61 to enter the second heat exchange element 62 under a fault condition, so as to ensure that the emergency refrigerant is provided to the second heat exchange element 62 in a timely manner, so that the emergency refrigerant can exchange heat with the steam flowing out of the condensing element 10.

[0066] In some embodiments, the first flow control element 232 , the second flow control element, and the third flow control element 64 in the embodiment of the present application can be implemented by valves, for example, automatic valves or manual valves.

[0067] In some embodiments, the cryogenic distillation system can be configured to include a single-stage distillation tower or a multi-stage distillation tower. Figure 3is a schematic structural diagram of a cryogenic distillation system according to a third embodiment of the present application. Figure 4 FIG. 1 is a schematic structural diagram of a cryogenic distillation system according to a fourth embodiment of the present application. Figure 3 and Figure 4 As shown, the number of condensing elements 10, first heat recovery elements 21, second heat recovery elements 22, compression elements 231, reboiler elements 30, expansion elements 41 and first heat exchange elements 50 in the cryogenic distillation system is respectively multiple, and the cryogenic distillation system also includes a first tower body 711 and a second tower body 712, each tower body being connected to a reboiler element 30 and a condensing element 10, respectively.

[0068] In some embodiments, because the media abundance at the top and bottom of each distillation tower differs, each stage of the cryogenic distillation system is configured to have an independent circulation system. The product of the reboiler 30 of the primary distillation tower enters the tower body of the secondary distillation tower as an intermediate product. In such an embodiment, the cryogenic distillation system further includes a separator 72, connecting the reboiler 30 of the primary distillation tower to the second tower body 712 of the secondary distillation tower via the separator 72, to ensure that the operating pressures of each distillation tower are relatively independent and do not affect each other.

[0069] The embodiment of the present application further provides a cryogenic distillation method, which is applicable to the cryogenic distillation system of the embodiment of the present application. Figure 5 FIG. 1 is a flow chart of a cryogenic distillation method according to an embodiment of the present application, as shown in FIG. Figure 5 As shown, the cryogenic distillation method may at least include the following steps S1 to S8.

[0070] S1. Precool the condensing element 10 of the cryogenic distillation system and utilize the first heat exchange element 50 of the cryogenic distillation system for heat exchange.

[0071] S2. During the cryogenic distillation process, the condensing element 10 is used to separate the process material at the top of the tower into gas and liquid, and the separated liquid material is transported to the reboiling element 30 of the cryogenic distillation system, and the vapor at the top of the tower is transported to the first heat recovery element 21 of the cryogenic distillation system.

[0072] S3. The steam flowing out of the condensing unit is initially heated by the first heat recovery unit 21, and then the steam is heated again by the second heat recovery unit 22 of the cryogenic rectification system until the steam reaches a predetermined temperature.

[0073] S4. The vapor at a predetermined temperature is transported to the compression assembly 23 of the cryogenic distillation system, and the compression assembly 23 is used to compress the vapor.

[0074] S5 . The compressed steam is transported to the reboiler 30 and the first heat exchange element 50 .

[0075] S6 , heating the liquid material in the reboiler 30 to vaporize the liquid material to form a gas material, and then transporting the gas material to the condenser 10 .

[0076] S7. The liquefied material in the reboiler 30 and the liquefied material after heat exchange in the first heat exchanger 50 are transported to the first heat recovery member 21 for cooling, so that the first heat recovery member 21 transports the cooled partially liquid material to the circulation drive member 40 of the cryogenic distillation system.

[0077] S8. Utilize the circulation drive member 40 to circulate the liquid material to the condensation member 10.

[0078] The low-temperature distillation method provided by the embodiment of the present application heats the vapor at the top of the tower in sequence through the first heat recovery component 21, the second heat recovery component 22 and the compression assembly 23, and then transports the heated vapor to the reboiler component 30, which can provide heat for the reboiler component 30, thereby reducing the energy consumption of the reboiler component 30. The liquid material flowing out of the reboiler component 30 and the first heat exchange component 50 is circulated back to the condenser component 10 through the first heat recovery component 21 and the circulation drive component 40, so that the liquid material can absorb the heat of the gas in the condenser component 10, thereby achieving the purpose of providing cooling capacity for the condenser component 10, which is beneficial to reducing the energy consumption of the condenser component 10, and further reducing the energy consumption of the entire low-temperature distillation system.

[0079] The working process of the cryogenic distillation system of the present application will be described in detail below with reference to specific embodiments.

[0080] The cryogenic distillation system of the embodiment of the present application is a three-stage distillation system with an operating temperature of -178°C, and is used for cryogenic distillation of process material carbon monoxide.

[0081] like Figure 3 and Figure 4 As shown, the cryogenic distillation system includes two condensing elements 10, two reboiler elements 30, two first heat recovery elements 21, two second heat recovery elements 22, two compression elements 231, two first flow control elements 232, two first heat exchange elements 50, two expansion elements 41, a first tower body 711, a second tower body 712, and a separator 72. This cryogenic distillation system is a two-stage distillation system.

[0082] In some embodiments, during initial startup of the cryogenic distillation system, the refrigeration system first provides pre-cooling for each of the two condensing elements 10. At this point, there is no liquid in the two reboiler elements 30, and therefore all heat is removed by the first heat exchange element 50. Once pre-cooling reaches a point where liquid appears in the two reboiler elements 30, the power of each reboiler element 30 gradually increases. When the power of each reboiler element 30 increases to match the power of the corresponding condensing element 10, the entire cryogenic distillation system reaches a stable equilibrium and enters a stable distillation process. At this point, the carbon monoxide absorbs heat from the overhead vapor in each condenser element 10, evaporating into a gas. The gaseous carbon monoxide then enters the first and second regenerator elements 21, 22 of each distillation column in sequence to increase in temperature. Once the gaseous carbon monoxide reaches a predetermined temperature, it enters the corresponding compression element 231 for further heating and pressure increase. It is then diverted and regulated by the first flow control element 232. When the power of each condenser element 10 and the power of the reboiler element 30 are fully matched, the gaseous carbon monoxide all enters the reboiler element 30. If the power of each condenser element 10 and the power of the reboiler element 30 are not matched, some of the gaseous carbon monoxide enters the reboiler element 30, while the remaining gaseous carbon monoxide enters the corresponding first heat exchange element 50, where the excess heat is dissipated. After entering the reboiler element 30, the gaseous carbon monoxide releases heat, cools down, condenses into a liquid phase, mixes with the liquid carbon monoxide exiting the first heat exchange element 50, and enters the corresponding first heat exchange element 21. The liquid carbon monoxide flowing out of the first heat recovery element 21 expands in the expansion element 41 and its pressure continues to drop, and then returns to the condensation elements 10 of each stage.

[0083] Under fault conditions, the first control part 631 of the second flow control element is closed and the second control part 632 is opened, and then the third flow control element 64 is opened. At this time, the gaseous carbon monoxide in each stage of the condensation element 10 enters the second heat exchange element 62 through their respective second control parts 632, and is condensed into liquid by the emergency refrigerant delivered by the working fluid storage element 61, and then returns to the condensation element 10. At the same time, the reboiler element 30 stops heating.

[0084] In some embodiments, as Figure 3 and Figure 4 As shown, the output of the reboiling section 30 of the primary distillation column can be fed into the second column body 712 as an intermediate product, and the product of the second column body 712 is output from the reboiling section 30 of the secondary distillation column. The top discharge of the condensing section 10 of the primary distillation column can be output as a by-product. The top discharge of the condensing section 10 of the secondary distillation column can be output as a product.

[0085] Understandably, Figure 4In the illustrated embodiment, the cryogenic distillation system includes a working fluid storage element 61 , each of which is connected to a second heat exchange element 62 . In other embodiments, the cryogenic distillation system may include multiple working fluid storage elements 61 , each of which is connected to a second heat exchange element 62 .

[0086] Regarding the embodiments of the present application, it should also be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other to obtain new embodiments.

[0087] The above description is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A cryogenic distillation system, suitable for cryogenic distillation of process materials, characterized in that: It includes a condensing element, a first heat recovery element, a second heat recovery element, a compression component, a reboiler element, a circulation drive element and a first heat exchange element. The condensing element is configured to perform gas-liquid separation on the process material at the top of the tower to obtain liquid material, and is configured to transport the liquid material to the reboiler, and transport the vapor at the top of the tower to the first heat recovery element; The first heat recovery element is configured to initially heat the steam; The second heat recovery element is configured to heat the steam again until the steam reaches a predetermined temperature; The compression assembly is configured to compress the vapor at the predetermined temperature and then deliver the vapor to the reboiler and the first heat exchange element; The reboiler is configured to heat the liquid material to vaporize the liquid material to form a gaseous material, and to liquefy the vapor to form a liquid material, and to transport the gaseous material to the condenser; The first heat exchange element is configured to at least exchange heat with the steam at the predetermined temperature; The first heat exchange element and the reboiler element are further configured to transport the liquid material to the first heat recovery element for cooling, so that the first heat recovery element transports the cooled liquid material to the circulation drive element; The circulation driving member is configured to circulate and drive the liquid material to the condensing member.

2. The cryogenic distillation system according to claim 1, characterized in that: When the height difference between the condensing element and the compression assembly is greater than or equal to a preset height difference, the circulation driving element includes an expansion element and a driving element. The expansion member is connected to the first heat recovery member and is configured to expand the cooled liquid material to reduce the pressure of the material; The driving member is connected to the expansion member and the condensation member respectively, and is configured to drive the material in the expansion member to enter the condensation member.

3. The cryogenic distillation system according to claim 1, characterized in that: When the height difference between the condensing element and the compression assembly is less than the preset height difference, the circulation driving element is an expansion element. The expansion member is connected to the first heat recovery member and the condensation member respectively, and is configured to expand the cooled liquid material to reduce the pressure of the liquid material, and is configured to transport the expanded liquid material to the condensation member.

4. The cryogenic distillation system according to claim 2 or 3, characterized in that: The condensing component, the first heat recovery component, the second heat recovery component and the compression assembly are connected in sequence.

5. The cryogenic distillation system according to claim 4, characterized in that: The compression assembly includes a compression element and a first flow control element, The compression component is connected to the reboiler component and the first heat exchange component respectively via the first flow control component, and the compression component is also connected to the second heat recovery component.

6. The cryogenic distillation system according to claim 5, characterized in that: The first flow control element is configured to control the compression element to be in communication with the reboiler element and to be disconnected from the first heat exchange element when the power of the reboiler element matches that of the condenser element.

7. The cryogenic distillation system according to claim 6, characterized in that: The first flow control component is further configured to control the compression component to be in communication with the reboiler component and the first heat exchange component respectively when the power of the reboiler component does not match that of the condenser component.

8. The cryogenic distillation system according to any one of claims 1 to 7, characterized in that: The cryogenic distillation system further includes an emergency component, The emergency component is configured to provide emergency refrigerant to the condensing element under a fault condition.

9. The cryogenic distillation system according to claim 8, characterized in that: The emergency component includes: a working medium storage component, a second heat exchange component and a second flow control component. The second flow control element is configured to control the steam in the condensing element to enter the first heat recovery element under normal working conditions, and the steam does not enter the second heat exchange element; The second flow control element is further configured to control the steam in the condensing element to enter the second heat exchange element under the fault condition, and the steam does not enter the first heat recovery element; The working medium storage element is configured to provide the refrigerant to the second heat exchange element under the fault condition, so as to condense the steam in the second heat exchange element.

10. A cryogenic distillation method, applicable to the cryogenic distillation system according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: S1. Precooling the condensing element of the cryogenic distillation system and exchanging heat with the first heat exchange element of the cryogenic distillation system; S2. During the cryogenic distillation process, the condensing element is used to separate the process material at the top of the tower into gas and liquid, and the separated liquid material is transported to the reboiling element of the cryogenic distillation system, and the vapor at the top of the tower is transported to the first reheat element of the cryogenic distillation system; S3, initially heating the vapor flowing out of the condensing element using the first heat recovery element, and then heating the vapor again using the second heat recovery element of the cryogenic rectification system until the vapor reaches a predetermined temperature; S4, transporting the vapor at the predetermined temperature to a compression component of the cryogenic rectification system, and compressing the vapor by using the compression component; S5, transporting the compressed steam to the reboiler and the first heat exchange element; S6. Heating the liquid material in the reboiler to vaporize the liquid material to form a gaseous material, and transporting the gaseous material to the condenser; S7, transporting the liquefied material in the reboiler and the liquefied material after heat exchange in the first heat exchange element to the first heat regeneration element for cooling, so that the first heat regeneration element transports the cooled partially liquid material to the circulation drive element of the cryogenic rectification system; S8. Utilize the circulation drive member to circulate the liquid material to the condensation member.

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