A desorption column for a co2 capture system and a capture system

Abstract

The application relates to a desorption tower and a capture system for a CO2 capture system, the desorption tower comprising a tower body, at least two desorption units and a temperature control unit arranged in the tower body, a gas outlet arranged at the top of the tower body, and a circulation unit arranged outside the tower body; the at least two desorption units are arranged in sequence from top to bottom; the desorption unit comprises a plurality of micro-channel assemblies, a first feed inlet and a first discharge outlet; the micro-channel assemblies are used for cavitation treatment of liquid-phase materials and liquid-phase products, so that the desorption efficiency is improved; by arranging the temperature control unit and the circulation unit, when the temperature in the micro-channel assemblies is lower than a first preset temperature, the circulation unit is used to heat the liquid-phase products to a second preset temperature, and the liquid-phase products are sent to the next desorption unit to continue desorption, so that continuous desorption of the liquid-phase materials is realized, the desorption rate is improved, and the circulation unit does not need to heat all the liquid-phase materials, so that the desorption energy consumption is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to a desorption tower for a CO2 capture system and the capture system. BACKGROUND

[0002] The global warming and climate change caused by the greenhouse effect are increasingly serious, which threatens the sustainable development of mankind. Among various greenhouse gases leading to climate change, carbon dioxide has the highest contribution rate to the greenhouse effect and the greatest impact on the environment. Therefore, reducing the emission of carbon dioxide is an important measure to solve the greenhouse effect. Fossil energy is one of the main energy sources in China, and its combustion will produce a large amount of carbon dioxide. In order to cope with the adverse effects of a large amount of carbon dioxide, carbon dioxide capture technology is usually used to separate and capture carbon dioxide from flue gas after combustion of fossil fuels. The existing large-scale industrialized carbon dioxide capture technology is a chemical absorption capture technology using organic amine liquid as an absorbent. The chemical absorption capture technology refers to a method in which an absorbent is used to chemically react with carbon dioxide in flue gas in an absorption tower to form a liquid phase material with weak linkage, and then the liquid phase material is heated in a desorption tower to desorb carbon dioxide, so that the absorbent can be regenerated. In the prior art, a desorption tower with packing or tray as the main tower internal component is usually used to realize desorption and regeneration of the absorbent. SUMMARY

[0003] The present application relates to a desorption tower for a CO2 capture system and the capture system.

[0004] The technical solutions provided by the present application are as follows:

[0005] As a first aspect of the present application, the present application provides a desorption tower for a CO2 capture system, comprising a tower body, at least two desorption units and a temperature control unit arranged in the tower body, a gas outlet arranged at the top of the tower body, and a circulation unit arranged outside the tower body;

[0006] The at least two desorption units are arranged in sequence from top to bottom;

[0007] The desorption unit comprises a plurality of microchannel assemblies, a first feed inlet and a first discharge outlet, and the microchannel assemblies are connected with the first feed inlet and the first discharge outlet, respectively;

[0008] The microchannel assembly is used for cavitation treatment of liquid phase material exceeding a first preset temperature to obtain CO2 and liquid phase products;

[0009] The temperature control unit is configured to control the liquid-phase product in the micro-channel assembly to enter the circulating unit when the temperature in the micro-channel assembly is detected to be lower than a first preset temperature.

[0010] The circulating unit is connected with two adjacent desorption units, and a feed inlet of the circulating unit is connected with a first discharge outlet of the upper desorption unit, and a discharge outlet of the circulating unit is connected with a first feed inlet of the lower desorption unit, so as to heat the entered liquid-phase product to a second preset temperature; the second preset temperature is greater than the first preset temperature.

[0011] The micro-channel assembly is connected with the gas outlet.

[0012] In one or some embodiments, the micro-channel assembly comprises a distributor, a collector and a plurality of micro-channel elements.

[0013] One end of the micro-channel element is connected with the distributor, and the other end of the micro-channel element is connected with the collector.

[0014] In one or some embodiments, the micro-channel element is tubular, and the tube wall of the micro-channel element has a plurality of mesh holes.

[0015] The tube wall thickness of the micro-channel element is 3-10 mm, and the mesh hole diameter is 0.2-2 um.

[0016] In one or some embodiments, the desorption unit further comprises a liquid collecting tray, and the liquid collecting tray is arranged below the micro-channel assembly.

[0017] In one or some embodiments, the desorption unit further comprises a central gas collecting pipe, and the central gas collecting pipe is connected with the gas outlet.

[0018] In one or some embodiments, the tower body is provided with a liquid outlet.

[0019] A tower kettle is arranged below the desorption unit, and a tower kettle below the upper desorption unit is connected with the circulating unit, and a tower kettle below the lower desorption unit is connected with the liquid outlet.

[0020] In one or some embodiments, the opening size of the tower kettle is greater than the opening size of the liquid collecting tray.

[0021] In one or some embodiments, the circulating unit comprises a heat exchanger, a circulating pump and a circulating storage tank.

[0022] The circulating storage tank is connected with the circulating pump, and the circulating pump is connected with the heat exchanger.

[0023] In one or some embodiments, the desorption tower for the CO2 capture system further comprises a feed pipe connected to the first feed port and a discharge pipe connected to the first discharge port.

[0024] In one or some embodiments, the desorption tower for the CO2 capture system comprises a first desorption unit and a second desorption unit arranged in sequence from top to bottom.

[0025] The feed port of the circulation unit is connected to the first discharge port of the first desorption unit, and the discharge port of the circulation unit is connected to the first feed port of the second desorption unit, for heating the liquid-phase product to the second preset temperature.

[0026] As a second aspect of the embodiments of the present application, the embodiments of the present application provide a CO2 capture system comprising an absorption tower and the above-mentioned desorption tower for the CO2 capture system.

[0027] The absorption tower is connected to the desorption tower.

[0028] Based on the above technical solutions, the present application has the following beneficial effects compared with the prior art:

[0029] The desorption tower for the CO2 capture system provided by the embodiments of the present application performs cavitation treatment on the liquid-phase material or the liquid-phase product in the micro-channel assembly, uses the cavitation effect of the micro-channel assembly to create a high-flow-rate and low-pressure environment, and when the liquid-phase material passes through the micro-channel assembly, the pressure of the liquid-phase material is reduced, and when the pressure is lower than the saturated vapor pressure, the bubbles in the liquid-phase material will continuously expand and increase in volume. With the fluid flow, the bubbles reach the high-pressure and low-flow-rate area, and the bubbles collapse and break. The breaking process of a large number of small bubbles greatly promotes the decomposition of unstable amine salts in the liquid-phase material, promotes desorption of the liquid-phase material, and improves the desorption efficiency.

[0030] The desorption tower for the CO2 capture system provided by the embodiments of the present application is provided with a temperature control unit and a circulation unit, when it is detected that the temperature in the micro-channel assembly is lower than the first preset temperature, the liquid-phase product in the micro-channel assembly is controlled to pass into the circulation unit, the circulation unit is used to heat the liquid-phase product to the second preset temperature, and the liquid-phase product is sent to the next desorption unit for continuous desorption, so as to improve the desorption rate. Moreover, the circulation unit does not need to heat all the liquid-phase material, but only needs to heat the liquid-phase product lower than the first preset temperature, thereby reducing the energy consumption of desorption.

[0031] Other features and advantages of the present application will be set forth in the description that follows, and in part will be apparent from the description, or can be learned by practice of the application. The purposes and other advantages of the present application will be realized and attained by the structure particularly pointed out in the description, claims and drawings.

[0032] In order to make the above objectives, features and advantages of the present application more apparent, the following will describe a preferred embodiment in detail, and the accompanying drawings will be referred to, as follows. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0034] Figure 1 is a schematic diagram of the overall structure of the desorption tower provided by the embodiment of the present application;

[0035] Figure 2 is another schematic diagram of the overall structure of the desorption tower provided by the embodiment of the present application;

[0036] Figure 3 is Figure 1 is a sectional view of the desorption tower in the A-A direction shown in the figure;

[0037] Wherein: 1, tower body; 2, distributor; 3, micro-channel element; 4, collector; 5, micro-channel assembly; 6, annular pipe; 7, central gas collecting pipe; 8, liquid collecting tray; 9, heat exchanger; 10, circulating pump; 11, circulating tank; 12, tower kettle; 13, gas outlet; 14, liquid outlet; 15, low-pressure steam inlet; 16, condensate outlet; 17, first feed inlet; 18, first discharge outlet; 19, desorption unit; 20, temperature control unit; 21, circulating unit. DETAILED DESCRIPTION

[0038] The exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be accurately conveyed to those skilled in the art.

[0039] The exemplary embodiments will be described in detail herein with reference to the attached drawings. In the following description, like reference numerals refer to like elements, unless the context clearly dictates otherwise. The following description is not meant to limit the application to all of the embodiments described herein. Rather, the following description is meant to provide examples of apparatus and methods consistent with the application as detailed in the appended claims.

[0040] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0042] Embodiment one

[0043] The embodiment of the present application provides a desorption tower for a CO2 capture system, referring to Figure 1 As shown in the figure, it comprises a tower body 1, at least two desorption units 19 and temperature control units 20 arranged in the tower body 1, a gas outlet 13 arranged at the top of the tower body 1, and a circulating unit 21 arranged outside the tower body 1;

[0044] The at least two desorption units 19 are arranged in sequence from top to bottom;

[0045] The desorption unit 19 comprises a plurality of micro-channel assemblies 5, a first feed port 17 and a first discharge port 18, and the micro-channel assemblies 5 are connected with the first feed port 17 and the first discharge port 18 respectively;

[0046] The micro-channel assembly 5 is used for cavitation treatment of liquid phase materials exceeding a first preset temperature to obtain CO2 and liquid phase products;

[0047] The temperature control unit 20 is used to control the liquid phase product in the microchannel component 5 to be introduced into the circulation unit 21 when the temperature inside the microchannel component 5 is detected to be lower than the first preset temperature.

[0048] The circulation unit 21 is connected to two adjacent desorption units 19, and the inlet of the circulation unit 21 is connected to the first outlet 18 of the upper desorption unit 19, and the outlet of the circulation unit 21 is connected to the first inlet 17 of the lower desorption unit 19, for heating the introduced liquid phase product to a second preset temperature; the second preset temperature is greater than the first preset temperature.

[0049] The microchannel component 5 is connected to the gas outlet 13.

[0050] The desorption principle of this invention is as follows: the liquid material generated in the absorption tower is preheated and then introduced into the desorption tower. The cavitation effect of the microchannel component 5 promotes the decomposition of the liquid material, i.e., the reverse reaction of absorption, generating liquid products and releasing CO2. The liquid products are continuously desorbed within the desorption unit 19, thus regenerating the absorbent. Taking organic amine liquid as an example, the organic amine liquid absorbs CO2 in the absorption tower and reacts to generate amine salts, also called rich amine liquid. The absorption temperature in the absorption tower is approximately 45 degrees Celsius. This reaction is reversible. The rich amine liquid is preheated before being sent into the desorption tower at a preheating temperature of approximately 85–95 degrees Celsius. At this temperature, this invention uses the microchannel component 5 as the main internal component of the tower to perform cavitation treatment on the ammonium salt. The strong cavitation effect generated within the microchannels promotes the decomposition of unstable amine salts. Even at 75–85 degrees Celsius, the decomposition rate of amine salts can be above 40%, reducing the desorption temperature and energy consumption.

[0051] In this embodiment of the invention, the microchannel component 5 cavitation treats the liquid material from the absorption tower to obtain CO2 and a first liquid product. The generated CO2 is discharged through the gas outlet 13 at the top of the tower. When the temperature of the liquid material in the microchannel component 5 is lower than a first preset temperature, the first liquid product is introduced into the circulation unit 21. The circulation unit 21 heats the first liquid product to a second preset temperature and sends the heated first liquid product to the next desorption unit for further desorption, obtaining CO2 and a second liquid product. The generated CO2 is discharged through the gas outlet 13 at the top of the tower. When the temperature of the liquid material in the next desorption unit is lower than the first preset temperature, the second liquid product is introduced into the circulation unit 21. The circulation unit 21 heats the second liquid product to the second preset temperature and sends the heated second liquid product to the next desorption unit for further desorption. This process is repeated until the desorption rate of the liquid material reaches the preset requirement. The first liquid product and the second liquid product refer to the desorbed amine-rich liquid and the undesorbed amine-rich liquid, respectively. Taking an organic amine liquid (i.e., rich amine liquid) as an example, since the liquid material needs to absorb heat during desorption, the rich amine liquid in the microchannel component 5 cools down. When the temperature is lower than the first preset temperature, the desorption rate of the rich amine liquid does not meet the preset requirements. Therefore, when the rich amine liquid in the microchannel component 5 of this invention is lower than the first preset temperature, the desorbed rich amine liquid and the undesorbed rich amine liquid are sent to the circulation unit 21. The circulation unit 21 heats the desorbed rich amine liquid and the undesorbed rich amine liquid to raise their temperature to the second preset temperature, and then sends them to the next desorption unit to continue desorption. This achieves the cyclic heating and continuous desorption of the rich amine liquid, and finally obtains a lean amine liquid, i.e., the absorbent, so that the absorbent is regenerated, which can effectively improve the desorption rate.

[0052] In this embodiment of the invention, the number of desorption units 19 can be set according to the desorption reaction efficiency of the amine-rich solution, and the number of desorption units 19 is at least two.

[0053] In a specific embodiment, such as Figure 2 As shown, there are two desorption units 19, including a first desorption unit 100 and a second desorption unit 200, which are arranged sequentially from top to bottom;

[0054] The circulation unit 21 is connected to the first desorption unit 100 and the second desorption unit 200, and the inlet of the circulation unit 21 is connected to the first outlet 18 of the first desorption unit 100, and the outlet of the circulation unit 21 is connected to the first inlet 17 of the second desorption unit 200, for heating the introduced liquid phase product to a second preset temperature.

[0055] The temperature control unit described in this embodiment of the invention may include a temperature sensor and a control valve. When the temperature sensor detects that the temperature of the liquid phase material in the microchannel component 5 is lower than a first preset temperature, the control valve opens, allowing the undesorbed amine-rich liquid to flow into the circulation unit 21. Specific implementation details can be found in the prior art. The specific structural form of the temperature control unit is not specifically limited in this embodiment of the invention.

[0056] The circulation unit 21 described in this embodiment of the invention can be one or more. When using one circulation unit 21, the inlet of the circulation unit 21 is connected to the first outlet 18 of the upper desorption unit 19, and the outlet of the circulation unit 21 is connected to the first inlet 17 of the lower desorption unit 19. When using multiple circulation units 21, the circulation unit 21 is connected between two adjacent desorption units 19, the inlet of the circulation unit 21 is connected to the first outlet 18 of the previous desorption unit, and the outlet of the circulation unit 21 is connected to the first inlet 17 of the next desorption unit. To save costs, this embodiment of the invention uses one circulation unit 21 to heat the liquid phase product below a first preset temperature.

[0057] In this embodiment of the invention, the number of microchannel components 5 can be set according to the desorption amount, and multiple microchannel components 5 can be arranged in the tower body 1 according to actual needs. For example, the microchannel components 5 can be arranged in layers in the tower body 1, and the number of microchannel components 5 in each layer can be set according to actual needs, as shown in the reference. Figure 3 As shown, the number of microchannel components 5 in each layer can be 8, and the 8 microchannel components 5 are evenly spaced along the central axis of the tower body 1.

[0058] In this embodiment of the invention, the microchannel assembly 5 includes a dispenser 2, a collector 4, and a plurality of microchannel elements 3;

[0059] One end of the microchannel element is connected to the dispenser 2, and the other end of the microchannel element 3 is connected to the collector 4.

[0060] In this embodiment of the invention, the liquid phase material is distributed to each microchannel element 3 by the distributor 2, and the undesorbed amine-rich liquid in each microchannel element 3 is collected by the collector 4. The internal flow channels of the distributor 2 and the collector 4 are uniformly distributed, which can ensure that the flow rate and resistance drop to each microchannel element 3 are the same.

[0061] In one specific embodiment, the microchannel elements 3 are uniformly arranged around the distributor 2. The arrangement diameter range of the microchannel elements 3 can be set according to the desorption amount of the liquid phase material, such as setting the arrangement diameter range of the microchannel elements 3 to 10 to 15 times the diameter of the microchannel elements 3. The number of microchannel elements 3 can also be set according to the desorption amount of the liquid phase material, such as 3 to 5 microchannel elements.

[0062] In one specific embodiment, in the microchannel assembly 5, the upper end of the microchannel element 3 is connected to the distributor 2 via a flange, and the lower end of the microchannel element 3 is connected to the collector 4 via a flange, facilitating disassembly and replacement. Of course, in this embodiment of the invention, the fixed connection method between the microchannel element 3, the distributor 2, and the collector 4 can refer to the detailed description in the prior art, and is not specifically limited here.

[0063] In this embodiment of the invention, the microchannel element 3 is tubular, and its tube wall has multiple mesh holes;

[0064] The wall thickness of the microchannel element 3 is 3-10 mm, and the pore size of the mesh is 0.2-2 μm.

[0065] In one specific embodiment, the wall of the microchannel element 3 is a multi-micron-level channel structure with a certain thickness. The microchannel element 3 can be made by sintering different kinds of metal wires, ceramics and additives into felt and rolling them up. The microchannel element 3 is tubular with an inner diameter of 25 to 80 mm.

[0066] In this embodiment, a high-flow-rate, low-pressure environment is established using the microchannel component 5. When the amine-rich liquid flows from the distributor 2 through the microchannel component 5, the pressure of the amine-rich liquid decreases due to the sharp reduction in pipe diameter. When the pressure is lower than the saturated vapor pressure, the bubbles in the liquid continuously expand, increasing in volume. As the fluid flows, the bubbles reach the high-pressure, low-flow-rate region (i.e., inside the microchannel), where they collapse and rupture. The rupture of numerous small bubbles greatly promotes the decomposition of unstable amine salts in the amine-rich liquid, generating new gas and forming new bubbles. The unstable amine salts in the amine-rich liquid continue to decompose, improving the mass transfer efficiency from the liquid phase to the gas phase during the desorption process and promoting the desorption of the amine-rich liquid.

[0067] In one specific embodiment, the microchannel assembly 5 consists of 5 microchannel elements 3. The microchannel elements 3 are made of metal wires sintered into felt and rolled into a tube shape with an inner diameter of 60 mm, a wall thickness of 5 mm, and a mesh size of 1 μm. The arrangement diameter of the microchannel elements 3 ranges from 10 times the diameter of the microchannel elements 3.

[0068] In this embodiment of the invention, the desorption unit 19 further includes a liquid collection tray 8, which is disposed below the microchannel assembly 5. (See reference...) Figure 1As shown, the liquid receiving tray 8 is an umbrella-shaped liquid receiving tray. The liquid receiving tray 8 is used to guide the desorbed amine-rich liquid flowing out of the microchannel assembly 5, preventing the desorbed amine-rich liquid from flowing into the microchannel assembly 5 below. As a specific embodiment, a liquid receiving tray 8 can be set below each layer of microchannel assembly 5 to guide the desorbed amine-rich liquid of that layer.

[0069] In this embodiment of the invention, the desorption unit 19 further includes a central gas collecting pipe 7, which is connected to the gas outlet 13. (Refer to...) Figure 1 As shown, the central gas collection pipe 7 is used to collect the CO2 generated by desorption and transport it to the gas outlet 13 at the top of the tower. The top of the desorption tower is connected to an extraction device. When the extraction device is started, a vacuum state is formed inside the desorption tower, with a vacuum degree of 4-10 kPa at the top of the tower. When the liquid material is circulated and desorbed in at least two desorption units 19, the desorbed CO2 is extracted by the extraction device, thus regenerating the absorbent. When the extraction device extracts CO2 gas, the vacuum state inside the tower further promotes desorption and improves desorption efficiency. The extraction device can be a fan or a vacuum pump.

[0070] In this embodiment of the invention, each layer of microchannel component 5 is provided with a corresponding liquid collection tray 8 and a central gas collection pipe 7. Gas-liquid separation of each layer of microchannel component 5 is achieved through the central gas collection pipe 7 and the liquid collection tray 8, thereby reducing the mutual influence between each layer of microchannel component 5.

[0071] In one specific embodiment, the maximum width of the receiving tray 8 is greater than the arrangement diameter of the plurality of microchannel components 5. By setting the maximum width of the receiving tray 8 to be greater than the arrangement diameter of the plurality of microchannel components 5, the amine-rich liquid desorbed from each layer of microchannel components 5 can be isolated, preventing the amine-rich liquid desorbed from the upper layer of microchannel components 5 from affecting the amine-rich liquid desorbed from the lower layer of microchannel components 5.

[0072] In this embodiment of the invention, the tower body 1 is provided with a liquid outlet 14;

[0073] A column bottom 12 is provided below the desorption unit 19, with the column bottom 12 below the upper desorption unit 19 connected to the circulation unit 21, and the column bottom 12 below the lower desorption unit 19 connected to the liquid outlet 14. The desorbed amine-rich liquid flowing from the microchannel assembly 5 is guided to the column bottom 12 via the oil collection tray 8, where it is collected. The desorbed amine-rich liquid in the column bottom of the upper desorption unit 19 enters the circulation unit 21 for heating, and the desorbed amine-rich liquid in the column bottom 12 of the last desorption unit is discharged through the liquid outlet 14 and returned to the absorption tower for continued use.

[0074] In this embodiment of the invention, the opening size of the column bottom 12 is larger than the maximum width of the collection tray 8. The larger opening size of the column bottom 12 allows all the desorbed amine-rich liquid flowing down from the collection tray 8 to be collected in the column bottom 12, preventing the desorbed amine-rich liquid from flowing into the next desorption unit and affecting the desorption process of that unit.

[0075] In this embodiment of the invention, a liquid outlet 14 is provided at the bottom of the tower body 1, and the liquid outlet is connected to the tower bottom 12. The liquid outlet 14 is the outlet for the absorbent lean amine solution. The absorbent lean amine solution from the last desorption unit can be collected by the tower bottom 12 and then fed into the absorption tower through the liquid outlet 14 to continue capturing CO2.

[0076] In this embodiment of the invention, reference is made to Figure 1 As shown, the circulation unit 21 includes a heat exchanger 9, a circulation pump 10, and a circulation storage tank 11;

[0077] The circulating storage tank 11 is connected to the circulating pump 10, and the circulating pump 10 is connected to the heat exchanger 9.

[0078] The inlet of the circulating storage tank 11 is connected to the first outlet 18 of the upper desorption unit, the outlet of the circulating storage tank 11 is connected to the inlet of the circulating pump 10, the outlet of the circulating pump 10 is connected to the inlet of the heat exchanger 9, and the outlet of the heat exchanger 9 is connected to the first inlet 17 of the lower desorption unit.

[0079] In this embodiment of the invention, the undesorbed and desorbed rich amine solution from the desorption unit 19 is stored in a circulating storage tank 11. The undesorbed and desorbed rich amine solution is then pumped to a heat exchanger 9 by a circulating pump 10. The heat exchanger 9 heats the undesorbed and desorbed rich amine solution to a second preset temperature, and then sends the heated solution to the next desorption unit for further desorption. The second preset temperature is 85–95°C, and the first preset temperature can be set according to the desorption efficiency of the rich amine solution, for example, it could be 75°C.

[0080] In this embodiment of the invention, the heat exchanger 9 can be a shell-and-tube heat exchanger, with low-pressure steam flowing through the shell side and the desorbed and undesorbed rich amine liquid flowing through the tube side. Low-pressure steam is used to heat both the desorbed and undesorbed rich amine liquids. The outlet temperature of the heat exchanger 9 is interlocked with the steam flow rate, and the low-pressure steam flow rate is controlled according to the outlet temperature of the heat exchanger 9. If the outlet temperature of the heat exchanger 9 is higher than a second preset temperature, the low-pressure steam flow rate is reduced; if the outlet temperature of the circulating absorbent is lower than the second preset temperature, the low-pressure steam flow rate is increased to bring the outlet temperature of the heat exchanger 9 up to the second preset temperature.

[0081] In this embodiment of the invention, the specific structure of the heat exchanger 9, the circulating pump 10 and the circulating storage tank 11 can be referred to the detailed description in the prior art. Those skilled in the art can make selections according to actual needs. In this embodiment of the invention, no specific limitation is made.

[0082] In this embodiment of the invention, the desorption tower for the CO2 capture system further includes a feed pipe and a discharge pipe, wherein the feed pipe is connected to the first feed inlet 17 and the discharge pipe is connected to the first discharge outlet 18. (Refer to...) Figure 1 As shown, one end of the feed pipe is connected to the first feed inlet 17, and the other end is connected to the distributor 2; one end of the discharge pipe is connected to the collector 4, and the other end is connected to the first discharge outlet 18. (Refer to...) Figure 1 As shown, the annular pipe 6 includes an annular feed pipe and an annular discharge pipe. The annular feed pipe has multiple openings, each of which is connected to the distributor 2 of the corresponding microchannel assembly 5 to deliver the amine-rich liquid to each microchannel assembly 5 through the annular feed pipe. Correspondingly, the annular feed pipe has multiple openings, each of which is connected to the collector 4 of the corresponding microchannel assembly 5 to allow the amine-rich liquid in the microchannel assembly 5 to be passed to the circulation unit 21 through the annular discharge pipe.

[0083] Example 2

[0084] Based on the same inventive concept, embodiments of the present invention provide a CO2 capture system, including an absorption tower and the above-mentioned desorption tower for a CO2 capture system;

[0085] The absorption tower is connected to the desorption tower.

[0086] In this embodiment of the invention, the absorbent in the absorption tower reacts chemically with CO2 to generate an amine salt, i.e., an amine-rich liquid. The ammonium salt, after preheating, is fed into the desorption tower. The amine salt undergoes continuous desorption in at least two desorption units 19 within the desorption tower, generating an organic amine liquid and releasing CO2. This achieves CO2 capture. By connecting the desorption tower and the absorption tower, the desorbed and regenerated absorbent can be recycled back into the absorption tower. The specific implementation of the CO2 capture system provided in this embodiment of the invention can be found in the detailed description of the desorption tower used in the CO2 capture system in Embodiment 1; repeated details will not be elaborated upon.

[0087] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. The terms "upper," "lower," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0088] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. This invention is not limited to any single aspect, nor to any single embodiment, nor to any combination and / or substitution of these aspects and / or embodiments. Each aspect and / or embodiment of this invention can be used alone, or in combination with one or more other aspects and / or other embodiments.

[0089] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A desorption tower for a CO2 capture system, characterized in that: It includes a tower body, at least two desorption units (19) and a temperature control unit (20) disposed within the tower body (1), a gas outlet (13) disposed at the top of the tower body (1), and a circulation unit (21) disposed outside the tower body (1); The at least two desorption units (19) are arranged sequentially from top to bottom; The desorption unit (19) includes multiple microchannel components (5), a first inlet (17) and a first outlet (18), wherein the microchannel components (5) are respectively connected to the first inlet (17) and the first outlet (18); The microchannel component (5) is used to cavitation process liquid materials exceeding a first preset temperature to obtain CO2 and liquid products; The temperature control unit (20) is used to control the liquid phase product in the microchannel component (5) to be introduced into the circulation unit (21) when the temperature in the microchannel component (5) is detected to be lower than the first preset temperature. The circulation unit (21) is connected to two adjacent desorption units (19), and the inlet of the circulation unit (21) is connected to the first outlet of the upper desorption unit, and the outlet of the circulation unit (21) is connected to the first inlet (17) of the lower desorption unit, for heating the introduced liquid phase product to a second preset temperature; the second preset temperature is greater than the first preset temperature; The microchannel component (5) is connected to the gas outlet (13).

2. The desorption tower for a CO2 capture system according to claim 1, characterized in that: The microchannel assembly (5) includes a dispenser (2), a collector (4), and multiple microchannel elements (3); The microchannel element (3) is connected to the distributor (2) and the collector (4) respectively.

3. The desorption tower for a CO2 capture system according to claim 2, characterized in that: The microchannel element (3) is tubular, and its tube wall has multiple mesh holes; The wall thickness of the microchannel element (3) is 3 to 10 mm, and the pore size of the mesh is 0.2 to 2 μm.

4. The desorption tower for a CO2 capture system according to claim 1, characterized in that: The desorption unit (19) further includes a liquid collection tray (8), which is disposed below the microchannel assembly (5).

5. The desorption tower for a CO2 capture system according to claim 1, characterized in that: The desorption unit (19) further includes a central gas collection pipe (7), which is connected to the gas outlet (13).

6. The desorption tower for a CO2 capture system according to claim 4, characterized in that: The tower body (1) is provided with a liquid outlet; A column bottom (12) is provided below the desorption unit (19), and the column bottom (12) below the upper desorption unit (19) is connected to the circulation unit, while the column bottom (12) below the lower desorption unit (19) is connected to the liquid outlet (14).

7. The desorption tower for a CO2 capture system according to claim 6, characterized in that: The opening size of the tower (12) is larger than the opening size of the liquid receiving tray (8).

8. The desorption tower for a CO2 capture system according to claim 1, characterized in that: The circulation unit (21) includes a heat exchanger (9), a circulation pump (10), and a circulation tank (11); The circulating storage tank (11) is connected to the circulating pump (10), and the circulating pump (10) is connected to the heat exchanger (9).

9. The desorption tower for a CO2 capture system according to claim 1, characterized in that: It includes a first desorption unit (100) and a second desorption unit (200), which are arranged sequentially from top to bottom; The inlet of the circulation unit (21) is connected to the first outlet (18) of the first desorption unit (100), and the outlet of the circulation unit (21) is connected to the first inlet (17) of the second desorption unit (200), which is used to heat the introduced liquid phase product to a second preset temperature.

10. The desorption tower for a CO2 capture system according to claim 1, characterized in that: It includes a feed pipe and a discharge pipe, wherein the feed pipe is connected to the first feed port (17) and the discharge pipe is connected to the first discharge port (18).

11. A CO2 capture system, characterized in that, Includes an absorption tower and a desorption tower for a CO2 capture system as described in any one of claims 1-10; The absorption tower is connected to the desorption tower.

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