Intercolumn heat exchange system and method for a ccus absorber

Abstract

The application discloses a CCUS absorption tower interstage heat exchange system and method, and belongs to the technical field of carbon dioxide capture, which comprises an absorption section collecting tank, a riser is arranged on the absorption section collecting tank, a gap space is formed between a plurality of risers, a heat exchange tube bundle is arranged in the gap space of the riser, the heat exchange tube bundle is in communication with a cooling medium delivery main pipe, and a tube plate is arranged on the outer side wall of the absorption section collecting tank, and the two ends of the heat exchange tube bundle are respectively in sealed connection with corresponding tube plates. The heat exchange tube bundle is arranged by using the gap space of the riser, an external heat exchanger and a complex amine liquid delivery and circulation pipeline are not needed to be separately arranged, the number and specifications of equipment are reduced, and the procurement, installation and maintenance costs of the equipment are reduced.

Description

Technical Field

[0001] This application belongs to the field of carbon dioxide capture technology, and specifically relates to the heat exchange system and method between stages of CCUS absorber towers. Background Technology

[0002] In CCUS technology, the absorption tower is the core equipment for carbon dioxide capture, and amine liquid is usually used as the absorbent to absorb carbon dioxide from flue gas. However, the absorption reaction between carbon dioxide and amine liquid is an exothermic process, and as the reaction proceeds, a large amount of heat is released, causing the temperature of the amine liquid to rise.

[0003] Increased temperature has several adverse effects. On the one hand, it significantly inhibits the absorption rate of carbon dioxide because higher temperatures reduce the solubility of carbon dioxide in amine solution, making the reaction proceed more slowly. On the other hand, it reduces absorption efficiency, making it impossible to fully absorb carbon dioxide from the flue gas, resulting in higher carbon dioxide content in the emitted flue gas and affecting the overall capture effect of the CCUS system.

[0004] To address this issue, existing technologies often employ heat exchangers installed outside the absorption tower to cool the amine solution. However, this method has significant drawbacks. It requires drawing the amine solution outside the absorption tower for heat exchange before returning it to the tower. This not only increases investment and energy consumption in the conveying equipment but also introduces a delay in the heat exchange process, hindering the timely and effective removal of reaction heat. Furthermore, external heat exchangers require additional installation space, which increases the difficulty of layout and space costs for projects with limited space.

[0005] In addition, some absorption towers have separate heat exchange devices inside, but these devices are often complex in structure, occupy a lot of space inside the tower, and affect the flow and contact of the gas and liquid phases inside the tower, thus adversely affecting the absorption efficiency. Moreover, traditional internal heat exchange devices are difficult to integrate effectively with the interstage structure of the absorption tower (such as liquid collection tanks, gas risers, etc.), making it difficult to achieve efficient heat exchange while collecting the liquid phase and ensuring the flow of the gas phase.

[0006] Therefore, there is an urgent need for an interstage heat exchange system that can be integrated inside the absorption tower to remove the heat released by the carbon dioxide absorption reaction in a timely and efficient manner without affecting the gas-liquid flow and contact, so as to improve the absorption rate and efficiency of amine liquid for carbon dioxide, while reducing equipment investment and saving equipment space. Summary of the Invention

[0007] To address the above problems, this invention proposes a CCUS absorber interstage heat exchange system, comprising: An absorption section liquid collection tank is provided with an air lifting cylinder; gap spaces are formed between multiple air lifting cylinders. The heat exchange tube bundle is installed in the gap space of the air riser and is connected to the cooling medium delivery main pipe. The tube sheet is installed on the outer wall of the liquid collection tank of the absorption section, and the two ends of the heat exchange tube bundle are respectively sealed and connected to the corresponding tube sheet.

[0008] Furthermore, the heat exchange tube bundles are arranged in a straight line or staggered arrangement within the gap space.

[0009] Furthermore, a support member is provided inside the liquid collection tank of the absorption section, which is used to support and fix the heat exchange tube bundle.

[0010] Furthermore, the cooling medium conveying main pipe includes an inlet main pipe and an outlet main pipe; the inlet main pipe is located outside the main body of the absorption tower and is connected to the inlet end of the heat exchange tube bundle through branch pipes; The main outlet pipe is located outside the main body of the absorption tower and is connected to the outlet end of the heat exchange tube bundle through branch pipes.

[0011] Furthermore, the heat exchange tube bundle is made of stainless steel or titanium alloy.

[0012] Furthermore, the heat exchange tube bundle is sealed to the tube sheet by welding.

[0013] This invention proposes a method for interstage heat exchange in CCUS absorbers, based on the aforementioned interstage heat exchange system for CCUS absorbers, comprising the following steps: Inside the absorption tower, carbon dioxide-containing flue gas and amine liquid are brought into countercurrent contact in the absorption section. The amine liquid absorbs carbon dioxide and releases heat of reaction. The heated amine liquid flows down to the collection tank in the absorption section and is collected. The cooling medium is introduced into the heat exchange tube bundle through the cooling medium delivery main pipe; The cooling medium flows within the heat exchange tube bundle and exchanges heat with the amine liquid with increased temperature collected in the liquid collection tank of the absorption section through the tube wall. The cooled amine solution flows out from the liquid phase outlet of the collection tank in the absorption section for further processing or recycling.

[0014] Furthermore, the cooling medium is cooling water or chilled brine.

[0015] Further, the cooling medium is introduced into the heat exchange tube bundle via the cooling medium delivery main pipe, including: The cooling medium is introduced into the heat exchange tube bundle arranged in the gap space of the air riser through the inlet main pipe and the No. 1 branch pipe. The cooling medium after heat exchange is discharged from the absorption tower through the second branch pipeline and the outlet main pipe.

[0016] This invention proposes a CCUS absorber, including the aforementioned CCUS absorber interstage heat exchange system.

[0017] Compared with the prior art, this application has the following advantages: 1. This application integrates the heat exchange system into the liquid collection tank of the absorption section and arranges the heat exchange tube bundle in the gap space of the gas riser. It eliminates the need for separate external heat exchangers and complex amine liquid delivery and circulation pipelines, thereby reducing the number and specifications of equipment and lowering the procurement, installation and maintenance costs of the equipment. Compared with traditional external heat exchange methods, it can save on heat exchanger investment.

[0018] 2. By arranging the heat exchange tube bundles in a straight or cross pattern in the gap space of the riser, the interstage heat exchange system can remove the heat released by the reaction of carbon dioxide and amine liquid in a timely manner, thereby reducing the temperature of the amine liquid. This effectively alleviates the inhibitory effect of temperature rise on the absorption reaction, increases the carbon dioxide absorption rate, and significantly enhances the carbon dioxide capture capacity of the main body of the absorption tower.

[0019] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the overall structure in an embodiment of the present invention is shown.

[0022] Figure 2 A front view of an embodiment of the present invention is shown.

[0023] In the diagram, 1 is the air riser; 2 is the heat exchange tube bundle. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] This application provides a CCUS absorber interstage heat exchange system, including: refer to Figure 1 An absorption section liquid collection tank is provided with an air lifting cylinder 1; gap spaces are formed between multiple air lifting cylinders 1; refer to Figure 2 Heat exchange tube bundle 2 is installed in the gap space of air riser 1 and is connected to the cooling medium delivery main pipe. The tube sheet is installed on the outer wall of the liquid collection tank of the absorption section, and the two ends of the heat exchange tube bundle 2 are respectively sealed and connected to the corresponding tube sheet.

[0026] The absorption section collection tank is located in the absorption section of the absorption tower body to collect the amine liquid (liquid phase) sprayed down from above. The shape of the absorption section collection tank is adapted to the tower body of the absorption tower. The absorption section collection tank has an overall annular or circular structure. The bottom of the absorption section collection tank is provided with a liquid phase outlet, which can transport the collected amine liquid to the next absorption section or the circulation system. Above the absorption section collection tank, there is a riser 1. The riser 1 is evenly distributed on the cross-section of the collection tank. The riser 1 is used to allow the unabsorbed flue gas (gas phase) to rise to the next absorption section. The gap space between the riser 1 provides an installation position for the heat exchange tube bundle 2. The heat exchange tube bundle 2 is in direct contact with the amine liquid and adopts a reasonable arrangement to increase the heat exchange area and heat transfer coefficient, which can quickly and efficiently remove the heat of reaction and meet the heat removal requirements of the absorption tower.

[0027] The inlet main pipe and the outlet main pipe are located outside the main body of the absorption tower. The inlet main pipe is connected to the inlet end of the heat exchange tube bundle 2 through the first branch pipe, and the outlet main pipe is connected to the outlet end of the heat exchange tube bundle 2 through the second branch pipe.

[0028] The intermediate heat exchange system in this application can remove the heat released by the reaction of carbon dioxide and amine liquid in a timely manner, thereby reducing the temperature of the amine liquid; it effectively alleviates the inhibitory effect of temperature rise on the absorption reaction, increases the carbon dioxide absorption rate, and significantly enhances the carbon dioxide capture capacity of the main body of the absorption tower.

[0029] This application integrates the heat exchange system into the liquid collection tank of the absorption section, and arranges the heat exchange tube bundle 2 in the gap space of the gas riser 1. There is no need to set up a separate external heat exchanger and complex amine liquid transportation and circulation pipelines, which reduces the number and specifications of equipment and lowers the procurement, installation and maintenance costs of equipment. Compared with the traditional external heat exchange method, it can save on heat exchanger investment.

[0030] Meanwhile, this application organically combines the heat exchange system with the liquid collection tank and the gas riser 1 of the absorption section, making full use of the idle space inside the absorption tower body. It does not require additional space outside the absorption tower body, greatly saving space, and is especially suitable for CCUS projects with limited space.

[0031] In this application, the heat exchange tube bundle 2 is arranged in the gap space of the riser 1, which will not hinder the upward flow of the gas phase in the riser 1, nor will it affect the collection and transportation of the liquid phase in the liquid collection tank, thus ensuring the normal flow and full contact of the gas and liquid phases in the absorption tower and ensuring the stable operation of the absorption process.

[0032] The heat exchange tube bundle 2 is arranged in a straight line or staggered arrangement within the gap space.

[0033] The heat exchange tube bundle 2 is immersed in the heat medium, and there are both co-current and cross-current flows with the heat medium, which improves the heat exchange efficiency.

[0034] The heat exchange tube bundle 2 can be arranged in a straight line or staggered to improve heat exchange efficiency.

[0035] The liquid collection tank of the absorption section is equipped with a support member, which is used to support and fix the heat exchange tube bundle 2. The support member is a support plate or a spacer tube.

[0036] The cooling medium conveying main pipe includes an inlet main pipe and an outlet main pipe; the inlet main pipe is located outside the main body of the absorption tower and is connected to the inlet end of the heat exchange tube bundle 2 through branch pipes; The main outlet pipe is located outside the main body of the absorption tower and is connected to the outlet end of the heat exchange tube bundle 2 through branch pipes.

[0037] The position of the heat exchange tube bundle 2 is fixed by a support plate or a spacer tube to prevent the heat exchange tube bundle 2 from vibrating or displacing due to fluid impact during operation, thus ensuring the stability and safety of the system.

[0038] The heat exchange tube bundle 2 is made of stainless steel or titanium alloy.

[0039] The heat exchange tube bundle 2 is made of high-efficiency heat exchange tubes such as stainless steel tubes or titanium alloy tubes, which can be selected according to the corrosiveness and other characteristics of the amine liquid. The shape and size of the heat exchange tube bundle 2 are set according to the size and distribution of the gap space between the gas lifters 1. The heat exchange tubes are arranged in an orderly manner in the gap space between the gas lifters 1 so that these idle spaces can be fully utilized without affecting the gas phase flow function of the gas lifters 1 and the liquid phase collection function of the liquid collection tank of the absorption section.

[0040] In one embodiment of the present invention, the heat exchange tube bundle 2 is sealed to the tube sheet by welding.

[0041] The two ends of the heat exchange tube bundle 2 are connected to the tube sheets at both ends by welding or flange sealing to form a closed heat exchange pipeline.

[0042] During operation, the amine liquid is sprayed down from above the absorption tower body, comes into contact with the rising flue gas and absorbs carbon dioxide, while releasing heat. The amine liquid that has absorbed heat falls into the liquid collection tank of the absorption section. While the liquid collection tank collects the liquid phase, the heat exchange tube bundle 2 arranged in the gap space of the gas riser 1 is in full contact with the amine liquid. The cooling medium flows continuously in the heat exchange tube bundle 2 and exchanges heat with the amine liquid through the wall of the heat exchange tube bundle 2, so as to carry away the reaction heat in the amine liquid in time and transfer it to the outside of the absorption tower body, thereby reducing the temperature of the amine liquid and maintaining a high absorption rate and absorption efficiency.

[0043] This application provides a method for interstage heat exchange in a CCUS absorber, based on the aforementioned interstage heat exchange system in a CCUS absorber, comprising the following steps: Inside the absorption tower, carbon dioxide-containing flue gas and amine liquid are brought into countercurrent contact in the absorption section. The amine liquid absorbs carbon dioxide and releases heat of reaction. The heated amine liquid flows down to the collection tank in the absorption section and is collected. The cooling medium is introduced into the heat exchange tube bundle 2 through the cooling medium delivery main pipe; The cooling medium flows within the heat exchange tube bundle 2 and exchanges heat with the amine liquid with increased temperature collected in the liquid collection tank of the absorption section through the tube wall. The cooled amine solution flows out from the liquid phase outlet of the collection tank in the absorption section for further processing or recycling.

[0044] The cooling medium is cooling water or chilled brine.

[0045] The cooling medium is introduced into the heat exchange tube bundle 2 via the cooling medium delivery main pipe, including: The cooling medium is introduced into the heat exchange tube bundle 2 arranged in the gap space of the air riser 1 through the inlet main pipe and the No. 1 branch pipe; The cooling medium after heat exchange is discharged from the absorption tower through the second branch pipeline and the outlet main pipe.

[0046] This application provides a CCUS absorber, including the aforementioned CCUS absorber interstage heat exchange system.

[0047] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications 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.

Claims

1. A CCUS absorber interstage heat exchange system, characterized in that, include: An absorption section liquid collection tank is provided with an air lifting cylinder (1); a gap space is formed between the multiple air lifting cylinders (1); The heat exchange tube bundle (2) is set in the gap space of the air riser (1) and is connected to the cooling medium delivery main pipe; The tube sheet is installed on the outer wall of the liquid collection tank of the absorption section, and the two ends of the heat exchange tube bundle (2) are respectively sealed and connected to the corresponding tube sheet.

2. The CCUS absorber interstage heat exchange system according to claim 1, characterized in that, The heat exchange tube bundle (2) is arranged in a straight line or staggered arrangement in the gap space.

3. The CCUS absorber interstage heat exchange system according to claim 1, characterized in that, The liquid collection tank of the absorption section is provided with a support member, which is used to support and fix the heat exchange tube bundle (2).

4. The CCUS absorber interstage heat exchange system according to claim 1, characterized in that, The cooling medium conveying main pipe includes an inlet main pipe and an outlet main pipe; the inlet main pipe is located outside the main body of the absorption tower and is connected to the inlet end of the heat exchange tube bundle (2) through branch pipes; The main outlet pipe is located outside the main body of the absorption tower and is connected to the outlet end of the heat exchange tube bundle (2) through branch pipes.

5. The CCUS absorber interstage heat exchange system according to claim 1, characterized in that, The heat exchange tube bundle (2) is made of stainless steel or titanium alloy.

6. The CCUS absorber interstage heat exchange system according to claim 1, characterized in that, The heat exchange tube bundle (2) is sealed to the tube sheet by welding.

7. A CCUS absorber interstage heat exchange method, based on the CCUS absorber interstage heat exchange system according to any one of claims 1-5, characterized in that, Includes the following steps: Inside the absorption tower, carbon dioxide-containing flue gas and amine liquid are brought into countercurrent contact in the absorption section. The amine liquid absorbs carbon dioxide and releases heat of reaction. The heated amine liquid flows down to the collection tank in the absorption section and is collected. The cooling medium is introduced into the heat exchange tube bundle (2) through the cooling medium delivery main pipe; The cooling medium flows within the heat exchange tube bundle (2) and exchanges heat with the amine liquid collected in the absorption section collection tank through the tube wall, which has been heated. The cooled amine solution flows out from the liquid phase outlet of the collection tank in the absorption section for further processing or recycling.

8. The CCUS absorber stage heat exchange method according to claim 7, characterized in that, The cooling medium is cooling water or chilled brine.

9. The CCUS absorber stage heat exchange method according to claim 8, characterized in that, The cooling medium is introduced into the heat exchange tube bundle (2) via the cooling medium delivery main pipe, including: The cooling medium is introduced into the heat exchange tube bundle (2) arranged in the gap space of the air riser (1) through the inlet main pipe and the No. 1 branch pipe; The cooling medium after heat exchange is discharged from the absorption tower through the No. 2 branch pipeline and the outlet main pipe.

10. A CCUS absorption tower, characterized in that, The CCUS absorber interstage heat exchange system includes any one of claims 1-6.

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