Structured packing and absorption tower

Abstract

The invention relates to the technical field of mass transfer equipment, and discloses a structured packing and an absorption tower, the structured packing is used for carbon capture by an absorption method, the structured packing comprises: a heat exchange tube assembly comprising a plurality of heat exchange tubes for circulating a cooling medium; the fin assembly is used for making contact with process fluid and comprises a plurality of fin units, and the fin units are installed on the outer walls of the heat exchange pipes; wherein the plurality of fin units can jointly define a plurality of vertical mass transfer flow channels and a plurality of horizontal mass transfer flow channels, and the vertical mass transfer flow channels and the horizontal mass transfer flow channels are communicated with each other. The structured packing not only can realize full mixing of process fluid, but also can realize efficient removal of heat.

Description

Technical Field

[0001] This application belongs to the field of mass transfer equipment technology, and specifically relates to a structured packing and an absorption tower using the structured packing. Background Technology

[0002] Among numerous CO2 capture technologies, chemical solvent-based absorption (such as using amine solution, potassium carbonate solution, ammonia water, etc.) is one of the most mature and widely used post-combustion capture technologies. The core equipment of this technology is the absorption tower. In a typical counter-current operation absorption tower, CO2-containing flue gas (such as power plant flue gas, industrial kiln tail gas) enters from the bottom of the tower and flows upward; while the chemical absorbent (lean solution) is sprayed downward from the top of the tower. The gas and liquid phases are in full contact inside the tower, CO2 reacts chemically with the absorbent and is captured, the purified gas is discharged from the top of the tower, and the CO2-rich absorbent (rich solution) flows out from the bottom of the tower and is then sent to the regeneration tower for desorption, releasing a high-concentration CO2 gas stream. At the same time, the regenerated lean solution can be recycled.

[0003] To enhance the contact between the gas and liquid phases and improve the mass transfer rate and tower efficiency, various internal components are usually installed inside the absorption tower, among which packing is one of the most critical mass transfer elements.

[0004] However, when CO2 reacts with chemical absorbents (such as amine solutions like MEA and PZ), it releases a large amount of heat, causing the absorbent temperature to rise. The physical solubility of CO2 in the absorbent and the chemical reaction rate constant are usually negatively correlated with temperature, or have optimal values ​​only within a certain temperature range. Excessively high temperatures can lead to a decrease in absorption rate, an increase in solvent circulation volume, a dramatic increase in regeneration energy consumption, and a series of problems, including increased equipment size and investment costs.

[0005] The design and optimization goals of traditional packing materials are almost entirely focused on improving mass transfer performance, namely, how to provide the largest possible and continuously renewed effective contact area for the gas and liquid phases and promote their uniform distribution and flow. Therefore, traditional packing materials mainly play the role of "passive" mass transfer elements, lacking active and efficient heat exchange capabilities. The heat released during the reaction can only be indirectly and relatively delayed cooled by external coolers, which not only has limited heat exchange efficiency but also makes precise temperature control within the packing material difficult. Simultaneously, mass transfer (completed within the packing material) and heat exchange (completed in external heat exchangers) become two spatially separated independent unit operations. This separation not only leads to low energy utilization efficiency but also introduces equipment redundancy and system complexity. Summary of the Invention

[0006] The purpose of this application is to provide a structured packing that can achieve both thorough mixing of process fluids and efficient heat removal.

[0007] To achieve the above objectives, this application provides a structured packing for an absorption tower, the structured packing comprising:

[0008] A heat exchange tube assembly, comprising multiple heat exchange tubes for the flow of a cooling medium; A finned assembly for contacting process fluids and comprising multiple finned units mounted on the outer wall of the heat exchange tube; The multiple fin units can collectively define multiple vertical mass transfer channels and multiple horizontal mass transfer channels, and the vertical mass transfer channels and the horizontal mass transfer channels are interconnected.

[0009] In some embodiments, the structured packing is a layered structure and includes multiple packing unit layers arranged in parallel and spaced apart along a first direction, the multiple packing unit layers being connected into a whole by a support member; The packing unit layer includes a plurality of heat exchange tubes arranged in parallel intervals along a second direction, and the heat exchange tubes extend along a third direction.

[0010] In some implementations, the first direction, the second direction, and the third direction are mutually perpendicular to each other.

[0011] In some embodiments, the finned unit is a first fin and is connected between two adjacent heat exchange tubes of the packing unit layer, and the first fin has a plurality of through holes; The through holes on the plurality of first fins arranged sequentially along the first direction are interconnected to form the vertical mass transfer channel; The interlayer gap between any two adjacent packing unit layers forms the horizontal mass transfer channel.

[0012] In some embodiments, the through holes of two adjacent first fins along the first direction are staggered.

[0013] In some embodiments, the first fin extends in a wavy shape along the second direction.

[0014] In some embodiments, the finned unit includes a plurality of second fins symmetrically arranged on the outer wall of the heat exchange tube, and the second fins have a plurality of through holes; The through holes on the plurality of second fins arranged sequentially along the first direction are interconnected to form the vertical mass transfer channel; The two adjacent packing unit layers are interconnected through the through holes on the second fin to form the horizontal mass transfer channel.

[0015] In some embodiments, multiple finned units are staggered along the extension direction of the heat exchange tube; And / or, two adjacent fin units along the first direction are arranged at an angular offset.

[0016] In some embodiments, the structured packing is an annular layered structure comprising multiple concentrically arranged annular packing layers, each annular packing layer comprising multiple circumferentially arranged heat exchange tubes, and the multiple annular packing layers are connected as a whole by a support member.

[0017] In some embodiments, the heat exchange tube assembly further includes: A distributor for connecting to the inlet ends of the plurality of said heat exchange tubes; A collector for connecting to the outlet ends of the plurality of said heat exchange tubes.

[0018] A second aspect of this application provides an absorption tower, wherein the absorption tower has an internal packing layer, the packing layer comprising at least one structured packing as described above.

[0019] The structured packing according to the present invention includes a heat exchange tube assembly and a fin assembly. The fin assembly includes multiple fin units mounted on the outer wall of the heat exchange tube. These multiple fin units collectively define multiple vertical mass transfer channels and multiple horizontal mass transfer channels, which are interconnected. The inner cavity of the heat exchange tube is used to circulate a cooling medium to continuously and controllably remove the heat of reaction released during the mass transfer process. This maintains the reaction temperature within the absorption tower within a suitable range, effectively solving the technical problems of low removal efficiency, low temperature control accuracy, high cost, and equipment redundancy inherent in the prior art where the packing only serves as a mass transfer unit and requires an external cooler to remove the heat of reaction.

[0020] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without any inventive effort. In the drawings: Figure 1 This is a schematic diagram of the structure of an embodiment of the structured packing of the present invention; Figure 2 for Figure 1 A magnified view of a section at point A in the middle; Figure 3 for Figure 1 Front view diagram; Figure 4 for Figure 1 A left-view diagram; Figure 5 This is a schematic diagram of another embodiment of the structured packing of the present invention; Figure 6 for Figure 5 A magnified view of a section at point B in the middle; Figure 7 for Figure 5 Front view diagram; Figure 8 for Figure 5 A left-view diagram; Figure 9 This is a schematic diagram of another embodiment of the structured packing of the present invention; Figure 10 for Figure 9 A magnified view of a section at point C; Figure 11 for Figure 9 Front view diagram; Figure 12 for Figure 9 A left-view diagram; Figure 13 This is a schematic diagram of the first fin of the present invention having a wavy shape; Figure 14 These are schematic diagrams illustrating different arrangements of the heat exchange tubes of the present invention; Figure 15 This is a schematic diagram of the heat exchange tube assembly of the present invention.

[0022] Explanation of reference numerals in the attached figures Structured packing 100; Heat exchanger tube assembly 10; heat exchanger tube 11; inlet manifold 12; manifold inlet pipe 13; outlet manifold 14; manifold outlet pipe 15; First fin 21; Second fin 22; Through hole 20a; Support component 30. Detailed Implementation

[0023] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0024] In the existing technology, packing materials are mainly divided into two categories: random packing materials and structured packing materials.

[0025] Random packing: such as Raschig rings, Pall rings, stepped rings, etc., are filled in the tower in a random stacking manner. Its advantages are low cost and convenient loading and unloading, but it has disadvantages such as significant wall flow effect, large pressure drop and relatively low mass transfer efficiency.

[0026] Structured packing: such as common perforated metal plate corrugated packing and wire mesh corrugated packing, is composed of parallel metal plates or meshes with specific geometric shapes (such as corrugations) stacked and assembled in a certain pattern. It forms a series of regular and continuous channels inside. Compared with random packing, structured packing has significant advantages such as large throughput, low pressure drop, high mass transfer efficiency and small scale-up effect. Therefore, it has been widely used in modern large-scale and high-efficiency separation processes.

[0027] When CO2 reacts with a chemical absorbent, the release of heat causes the absorbent's temperature to rise. The physical solubility of CO2 in the absorbent and the chemical reaction rate typically have an optimal temperature range. When the temperature is too high, a series of problems will arise: 1. Decreased absorption rate: Increased temperature reduces the equilibrium solubility of CO2 in the solvent and shifts the reaction equilibrium in a direction unfavorable to absorption, resulting in a significant decrease in the absorption capacity of a unit volume of solvent for CO2.

[0028] 2. Increased solvent circulation volume: In order to compensate for the decrease in absorption rate caused by the increase in temperature, it is necessary to increase the solvent circulation flow rate to ensure that the specified CO2 removal rate is achieved. This will directly increase the energy consumption of the lean solution pump and the rich solution pump.

[0029] 3. Dramatically Increased Regeneration Energy Consumption: The rich liquid temperature at the absorber outlet is relatively high, requiring more steam (usually low-pressure steam) to provide the heat needed for desorption after entering the regeneration tower. The higher the operating temperature of the absorber, the greater the heat load on the regeneration tower, leading to a significant increase in the energy consumption (especially steam consumption) of the entire CO2 capture system, thus severely impacting the economics of the process.

[0030] 4. Increased equipment size and investment costs: To maintain the designed removal rate at higher operating temperatures, it is often necessary to increase the height of the absorption tower or the number of packing layers. This not only makes the tower taller and heavier, but also correspondingly increases the costs of infrastructure construction and equipment investment.

[0031] Furthermore, traditional structured packing acts only as a "passive" mass transfer element, lacking active and efficient heat exchange capabilities. Heat accumulation within the tower can only be achieved through the sensible heat of the gas and liquid phases themselves, or through indirect and passive cooling using a large intercooler installed outside the tower. This method is inefficient and cannot achieve precise control over the local temperature of the packing.

[0032] Because structured packing has a regular and ordered geometric structure, it provides a good structural basis for embedding another set of regular and ordered heat exchange channel systems within it. On the other hand, the heat of reaction released during the absorption reaction leads to a series of problems such as a decrease in the absorption rate, which urgently need to be solved through efficient thermal management methods. Furthermore, the most ideal way to remove the heat of reaction is to achieve immediate and efficient transfer and release at the location where the heat is generated. Based on the above understanding, in order to form a heat exchange structure on structured packing for timely and efficient removal of the heat of reaction, the inventors of this application have continuously considered and provided a structured packing with heat exchange channels. This structured packing can remove heat in situ, actively and efficiently while the mass transfer process is occurring, thereby effectively suppressing the decline in absorption performance caused by temperature rise. It should be noted that this invention does not simply combine the heat exchange components and the packing components together, but achieves synergy between the two through an integrated design. The heat exchange tube, the fins that extend the heat transfer surface, and the packing sheets that promote mass transfer are integrated to form a structure that is used for both efficient mass transfer and efficient heat exchange, realizing the simultaneous occurrence of mass transfer and heat exchange, and significantly improving the overall performance and economy of the CO2 absorption process.

[0033] This invention proposes a structured packing for absorption towers, which forms a single, compact tower internal with both high-efficiency mass transfer and high-efficiency heat exchange capabilities by installing finned units on the outer wall of the heat exchange tubes.

[0034] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0035] like Figures 1 to 13 As shown, in an embodiment of the present invention, the structured packing 100 includes a heat exchange tube assembly 10 and a fin assembly. The heat exchange tube assembly 10 includes multiple heat exchange tubes 11 for flowing cooling medium. The fin assembly is used to contact the process fluid and includes multiple fin units. The fin units are installed on the outer wall of the heat exchange tubes 11. The multiple fin units can jointly define multiple vertical mass transfer channels and multiple horizontal mass transfer channels, and the vertical mass transfer channels and the horizontal mass transfer channels are interconnected.

[0036] Understandably, this application fundamentally improves the structure of existing structured packings by designing a structured packing 100 with heat exchange channels, integrating heat exchange and mass transfer functions into one. Specifically, the heat exchange channel consists of the inner cavity of the heat exchange tube 11 and finned units installed on its outer wall. By constructing a continuous and controllable heat exchange channel inside the structured packing 100, the structured packing 100 provides a large gas-liquid contact area to promote CO2 mass transfer and absorption, while the cooling medium flowing through the heat exchange tube 11 (such as cooling water, low-temperature amine liquid, or other heat-conducting fluids) can remove the heat of reaction released during absorption in a timely manner, thereby achieving active and precise control of the internal temperature of the packing.

[0037] Both vertical and horizontal mass transfer channels are used for the flow of process fluids. Vertical channels facilitate the flow of process fluids from top to bottom or bottom to top within the absorber, aligning with the flow direction after the process fluid enters the absorber. Horizontal channels guide the process fluid to flow laterally within the structured packing 100, increasing reaction time and, through contact with the finned units, increasing the reaction area. The interconnected vertical and horizontal channels together form a three-dimensional mass transfer channel, allowing the process fluid to fully contact and react by increasing the flow path and contact area. Understandably, mass transfer channels can be formed by staggered fin arrangement, by openings in the fins, or by a combination of staggered fin arrangement and fin openings.

[0038] The structured packing according to the present invention has at least the following technical effects: 1. Structured packing integrates the mass transfer unit inside the tower and the heat exchange unit outside the tower in traditional processes through an integrated design. In other words, mass transfer and heat exchange can be completed simultaneously through the structure of the structured packing itself, achieving compact structure and process intensification, which is in line with the technological development trend of chemical process intensification. 2. By embedding heat exchange channels inside the structured packing, in-situ management of reaction heat is achieved, which can directly and efficiently remove heat from the reaction source, thereby maintaining the temperature of the packing surface and the liquid phase in the optimal range, thus ensuring the absorption efficiency of the absorbent and improving the overall energy efficiency. 3. This structured packing integrates the heat exchange tube, the fins that expand the heat transfer surface, and the packing sheets that promote mass transfer. This allows the fin units to simultaneously expand the heat transfer area and enhance heat transfer outside the tube. In addition, the fin units also serve as elements that provide gas-liquid contact surfaces for the structured packing channel walls, maximizing functionality within a limited space.

[0039] The heat exchange tube 11 is a closed channel for the flow of the cooling medium and is the core carrier for heat transfer. Its material selection requires comprehensive consideration of thermal conductivity, corrosion resistance, and mechanical strength. Commonly used materials include stainless steel (such as 304 and 316L), copper alloys, titanium, or duplex stainless steel, etc., and the specific choice should be determined based on the chemical properties of the cooling medium and process fluid, as well as the corrosive environment. The outer diameter of the heat exchange tube 11 is typically designed to be 5mm to 25mm, preferably 8mm to 15mm. Too small a diameter can easily lead to increased flow resistance and a risk of blockage, while too large a diameter will occupy too much mass transfer space within the tower, affecting overall efficiency. The wall thickness of the heat exchange tube 11 is between 0.5mm and 2.0mm. While meeting pressure requirements and corrosion allowances, it should be reduced as much as possible to lower thermal resistance and improve heat exchange performance.

[0040] The heat exchange tube assembly 10 can be arranged horizontally or vertically. Horizontal arrangement means that the extension direction of the heat exchange tube 11 is perpendicular to the flow direction of the gas and liquid phases in the absorption tower; vertical arrangement means that the extension direction of the heat exchange tube 11 is parallel to the flow direction of the gas and liquid phases in the absorption tower.

[0041] Furthermore, such as Figure 14 As shown, multiple heat exchange tubes 11 within the same heat exchange tube assembly 10 can also be arranged in different ways, specifically in a regular geometric distribution such as triangles, rectangles, rhombuses, or circles, for example... Figure 14 (a) shows a triangular arrangement. Figure 14 (b) shows a rectangular arrangement. Figure 14 (c) shows a diamond arrangement. The heat exchange tubes 11 in the same heat exchange tube assembly 10 can also be rotated by a specific angle, so that the fins are angularly misaligned. This can cause different fins in the same heat exchange tube 11 to be angularly misaligned, or cause fins corresponding to different positions of heat exchange tubes 11 to be angularly misaligned. The rotational arrangement can utilize the structural asymmetry to improve fluid distribution and enhance the mass transfer and heat exchange effect.

[0042] The finned assembly is a key structure for integrating mass transfer and heat exchange functions. The finned assembly is in direct contact with the process fluid (gas and liquid), directly exposed to the process fluid (gas and liquid two phases). Its main function is to expand the heat transfer area and to disturb the fluid flow. The finned unit is installed on the outer wall of the heat exchange tube 11. Each finned unit includes at least one fin. When multiple fins are installed on the outer wall of the heat exchange tube 11, the fins can be arranged in a straight line, staggered, or angularly offset manner to form a stable mass transfer and heat exchange interface. The fins and the heat exchange tube 11 are tightly connected through processes such as expansion, brazing, or high-frequency welding, achieving a reliable mechanical connection and good thermal contact, thereby minimizing the thermal resistance of the heat conduction path.

[0043] The finned assembly directly enhances heat transfer from the process fluid to the wall of the heat exchange tube 11 by increasing the contact area. The fin surface itself is the site of mass transfer reactions between the gas and liquid phases. The complex geometry of the fin surface, with its numerous through-holes 20a, facilitates the formation and renewal of the liquid film, increasing the effective mass transfer area. The simple yet effective design of machining regular through-holes 20a on the fins achieves three objectives simultaneously: enhanced heat transfer, enhanced mass transfer, and promoted uniform fluid distribution—a key detail for realizing a synergistic effect. Specifically, the shape of the fins and the through-holes 20a disrupt the flow boundary layer, increasing the turbulence of the fluid and simultaneously enhancing both heat and mass transfer.

[0044] Fin types can be divided into rectangular fins and wavy fins, such as... Figure 4 and Figure 13 As shown, the wave shape includes corrugated fins and wavy fins. Specifically, rectangular fins are rectangular flat plates. The outline of corrugated fins is a broken line with clear inflection points. Corrugated fins are pressed into continuous, regular wavy or sawtooth shapes. This structure can mechanically guide the fluid to change direction, generating strong turbulence. It is a classic structure for enhancing heat and mass transfer. The wave height and wave pitch can be adjusted to optimize performance. The cross-sectional shape of corrugated fins is similar to a sine wave, cosine wave, or a waveform with unequal peak and trough heights. Its outline is composed of smooth and continuous curves. Wavy fins can provide a large surface area while having relatively low airflow resistance. Understandably, the fins are not only an extended heat transfer surface but also a core mass transfer surface. The various fin shapes and combinations, such as corrugated and wavy, provided in this application can adapt to different process fluid dynamics and mass transfer requirements.

[0045] The function of fins is to allow some gas and liquid to pass directly through, realizing the exchange of mass and momentum between adjacent flow channels, making the flow rate, temperature and concentration distribution more uniform across the entire tower cross section; the edges of the holes will continuously break the flow boundary layer, enhance fluid disturbance, and thus improve heat transfer efficiency; the structure of perforated fins increases the frequency of gas-liquid contact, directly enhancing the mass transfer effect.

[0046] like Figures 1 to 13 As shown, different types of fins are all processed with through holes 20a. There are multiple through holes 20a arranged in a regular pattern. The diameter of the through holes 20a is designed to range from 1 mm to 8 mm, and the specific size can be selected according to the fouling deposition tendency of the processed system and the system pressure drop requirements. In the embodiments of the present invention, the spacing of the through holes 20a is designed to range from 3 mm to 15 mm. The arrangement of the through holes 20a is not limited to a regular straight or staggered arrangement, but can also adopt an optimized distribution pattern with variable spacing and variable diameter to match the local enhancement requirements of flow and mass and heat transfer.

[0047] The embodiments of the present invention, through functional integration and structural optimization, have at least the following technical effects: 1. This invention introduces the heat exchange function from outside the tower to inside the tower, realizing the simultaneous occurrence of mass transfer and heat exchange processes, that is, changing from "post-cooling" to "in-process cooling," fundamentally solving the "spatiotemporal mismatch" problem of reaction heat generation and removal. Through the dual-function design of the fins, the increase in heat transfer area not only improves heat exchange efficiency, but also expands the mass transfer interface area and improves fluid dynamic characteristics, thereby producing a synergistic enhancement effect of "1+1>2".

[0048] 2. By promptly removing the heat of reaction during the mass transfer process, the structured packing always operates within its optimal temperature range, avoiding the attenuation of the absorption rate due to temperature rise. Under the same operating conditions, the absorption tower using the structured packing of this invention can increase its overall volumetric mass transfer coefficient by approximately 15% to 30%, thereby achieving the same CO2 removal rate at a lower liquid-to-gas ratio or a smaller tower height.

[0049] 3. Reduced regeneration energy consumption: Since the present invention can effectively reduce the temperature of the rich liquid at the outlet of the absorption tower, the heat load of the solution entering the regeneration tower is reduced, and the amount of steam required for regeneration can be reduced by about 10% to 20%, which becomes the main source of cost savings for the entire capture system.

[0050] Reduced pumping energy consumption: The increased absorption rate allows for lower solvent circulation volumes, thereby reducing the power consumption of both lean and rich solution pumps.

[0051] Reduced fan energy consumption: Although the packing structure is slightly complex, the optimized flow design can control the pressure drop within a reasonable range. Even due to the reduction in gas volume flow rate caused by the decrease in temperature, the energy consumption of the induced draft fan will remain the same or decrease slightly.

[0052] 4. Due to the improved mass transfer efficiency, the diameter of the absorption tower and / or the height of the packing layer required to achieve the same processing capacity and removal rate can be reduced accordingly. This characteristic reduces the amount of tower body, foundation, and insulation materials used, making the equipment more compact and requiring less floor space, thereby reducing overall equipment investment and construction costs.

[0053] 5. By adjusting the flow and temperature of the refrigerant, the system can flexibly cope with fluctuations in CO2 concentration in flue gas and changes in inlet temperature, ensuring that the entire system always operates in the high-efficiency range, significantly improving the operational flexibility and environmental adaptability of the CO2 capture device.

[0054] 6. Effective temperature control can significantly slow down the thermal degradation rate of solvents, extend their service life, and reduce expensive solvent replenishment and waste liquid treatment costs, thereby further improving the system's economy and sustainable operation capabilities.

[0055] In some specific embodiments of the present invention, the structured packing 100 has a layered structure, including flat stacked type and concentric ring type.

[0056] like Figures 1 to 13 As shown, specifically, the flat-plate stack includes multiple packing unit layers arranged in parallel and spaced intervals along a first direction, and the multiple packing unit layers are connected into one unit by a support member 30; wherein, the packing unit layer includes multiple heat exchange tubes 11 arranged in parallel and spaced intervals along a second direction, and the heat exchange tubes 11 extend along a third direction. The spatial relationship between the first direction, the second direction, and the third direction can be mutually perpendicular or not. When these three directions are orthogonal to each other, that is, when the multiple heat exchange tubes 11 are arranged in a rectangular arrangement, the external shape of the regular packing 100 is cuboid, which is regular and convenient for stacking along the axial direction in the absorption tower.

[0057] The concentric annular type includes multiple concentrically arranged annular packing layers (not shown in the figure). Each annular packing layer includes multiple heat exchange tubes 11 arranged circumferentially. The multiple annular packing layers are connected into one unit by a support member 30. The concentric annular type focuses on improving the uniformity of fluid distribution and heat management across the tower cross-section. This structure arranges multiple vertical heat exchange tubes 11 into several concentric rings with the center of the absorption tower as the axis.

[0058] In the aforementioned layered structure, each packing layer is connected to form a whole by support members 30. Support members 30 improve the mechanical strength and structural stability of the structured packing 100, thereby fixing the relative positions of the heat exchange tube assembly 10 and the fin assembly, and withstanding gravity, fluid pressure drop, and potential vibration loads during operation. Support members 30 have various structural forms, such as a grid frame or grid plate structure composed of support bars or profiles. Support bars are made of metal to improve structural strength and connect between two aligned heat exchange tubes 11. Multiple support bars connect multiple heat exchange tubes 11 into a single unit. The grid frame or grid plate structure is a single unit with holes or slots that match the outer diameter of the heat exchange tubes 11, allowing the tubes 11 to pass through and be fixed. It should be noted that the support member 30 itself also provides a certain gas-liquid distribution and mixing function. Its material is compatible with the heat exchange tubes 11 and fins, and is usually the same type or a metal with better mechanical properties.

[0059] In an embodiment of the present invention, the heat exchange tube assembly 10 further includes a distributor and a collector. The distributor is connected to the inlet end of the heat exchange tube 11, and the collector is connected to the outlet end of the heat exchange tube 11. The distributor ensures that the cooling medium enters the inlet end of each heat exchange tube 11 evenly, while the collector ensures that the cooled medium after heat exchange flows smoothly from the outlet ends of all heat exchange tubes 11, thereby avoiding problems such as uneven flow, local overflow, or blockage.

[0060] like Figure 15As shown, the distributor includes an inlet manifold 12 and a manifold inlet pipe 13. The inlet manifold 12 is connected to the inlet ends of multiple heat exchange tubes 11 through the manifold inlet pipe 13. Specifically, the liquid inlet end of the inlet manifold 12 is connected to an external refrigerant pipeline and is located at the top or bottom of the absorption tower. The manifold inlet pipe 13 has one liquid inlet end and multiple liquid outlet ends, the same number as the heat exchange tubes 11. The liquid inlet end of the manifold inlet pipe 13 is connected to the liquid outlet end of the inlet manifold 12. After the cooling medium enters the manifold inlet pipe 13, it enters the interior of multiple heat exchange tubes 11 through the multiple liquid outlet ends, thereby achieving uniform distribution of the refrigerant.

[0061] like Figure 15 As shown, the collector includes an outlet manifold 14 and a manifold outlet pipe 15. The outlet manifold 14 is connected to the outlet ends of multiple heat exchange tubes 11 via the manifold outlet pipe 15. Specifically, the manifold outlet pipe 15 has multiple liquid inlets and one liquid outlet, the same number as the heat exchange tubes 11. The liquid inlets of the outlet manifold 14 are connected to the liquid outlet of the manifold outlet pipe 15. The manifold outlet pipe 15 collects the refrigerant that has absorbed heat flowing out of each heat exchange tube 11, and the outlet manifold 14 collects the refrigerant and sends it out of the absorption tower.

[0062] The main pipe and the manifold, as well as the manifold and the heat exchanger pipe 11, are usually connected by welding or flanges to ensure airtightness.

[0063] The following section provides a detailed explanation of different arrangements of structured packing 100 within the absorption tower.

[0064] First embodiment: like Figures 1 to 4 , Figure 13 As shown, multiple heat exchange tubes 11 are arranged horizontally to form the skeleton structure of the structured packing 100. Specifically, multiple heat exchange tubes 11 are arranged in parallel and spaced along the second direction to form a packing unit layer, and multiple packing unit layers are arranged in parallel and spaced along the first direction to form the structured packing 100. A fin unit is a first fin 21 connected between two adjacent heat exchange tubes 11 in the same packing unit layer. The extension direction of the first fin 21 is the same as the extension direction of the heat exchange tube 11, and the length of the first fin 21 is the same as the length of the heat exchange tube 11, to fully cover the flow area of ​​the gas and liquid phases and increase the contact area with the gas and liquid phases. The first fin 21 has multiple through holes 20a to promote the mixing of the gas and liquid phases. The two ends of the first fin 21 are welded to two adjacent heat exchange tubes 11 respectively. The first fin 21 is rectangular or wavy. The wavy shape means that the first fin 21 extends in a wavy pattern along the second direction. The wavy shape can be further divided into corrugated and wave-shaped. In practical applications, these fins of different shapes can be used independently or in combination according to performance requirements.

[0065] In this embodiment, the interlayer gap between any two adjacent packing unit layers forms a horizontal mass transfer channel. This horizontal mass transfer channel is defined by multiple first fins 21 on each packing unit layer and exhibits a continuous corrugated or wavy shape. The through-holes 20a on the multiple first fins 21 arranged sequentially along the first direction are interconnected to form a vertical mass transfer channel. Since the first fins 21 cover the flow area of ​​the gas and liquid phases, the gas and liquid phases flow upwards or downwards through the through-holes 20a on the first fins 21. The horizontal and vertical mass transfer channels together constitute the mass transfer channel through which the gas and liquid phases flow.

[0066] Second embodiment: The arrangement of the heat exchange tubes 11 in this embodiment is the same as in the first embodiment, except that the first fin 21 in the first embodiment is an integral structure, while the first fin 21 in this embodiment is a split structure including fin A and fin B. Both fin A and fin B have through holes 20a for the gas and liquid phases to pass through, improving the gas-liquid mixing effect. Specifically, the first fin 21 is located between two adjacent heat exchange tubes 11, with one end of fin A welded to the outer wall of one heat exchange tube 11, and one end of fin B welded to the outer wall of the other heat exchange tube 11. Fins A and fin B are connected to each other or have a small gap between adjacent heat exchange tubes 11, thereby forming a continuous horizontal flow channel with a corrugated or wavy shape. The horizontal mass transfer channel and the vertical mass transfer channel in this embodiment are the same as in the first embodiment, and will not be described in detail here.

[0067] Third embodiment: like Figures 5 to 8As shown, the heat exchange tube 11 arrangement in this embodiment is the same as in the first embodiment, except for the number and arrangement of the fin units. Specifically, the fin unit includes multiple second fins 22 symmetrically arranged on the outer wall of the heat exchange tube 11, and the second fins 22 have multiple through holes 20a. The second fins 22 are also fixed to the outer wall of the heat exchange tube 11 by welding. Multiple second fins 22 located on the same plane constitute an independent fin unit. In this embodiment, the fin units are all of the same type, that is, the arrangement direction of the second fins 22 in multiple fin units is the same. The multiple fin units are arranged along the axial direction of the heat exchange tube 11, and their arrangement can be either sequential or staggered to adapt to different flow and heat transfer optimization requirements. Specifically, taking a finned unit comprising two second fins 22 and multiple finned units arranged in a staggered manner along the axial direction of the heat exchange tube 11 as an example, the two second fins 22 located in the same finned unit are symmetrically arranged, and adjacent finned units are rotated and offset by 90° around the axis of the heat exchange tube. If the azimuth angles of the two second fins 22 in a certain finned unit are defined as 0° and 180° respectively, then the azimuth angles of the two second fins 22 in the adjacent finned unit are 90° and 270° respectively. From the axial projection direction, the circumferentially rotated and offset arrangement can promote the mixing of the gas and liquid phases.

[0068] In this embodiment, a horizontal mass transfer channel is formed between two adjacent packing unit layers. Since the second fins 22 are arranged at an angle between adjacent heat exchange tubes 11 and cover the horizontal flow area, this horizontal mass transfer channel is formed by the interconnection of adjacent packing unit layers through through-holes 20a on the second fins 22. In the same packing unit layer, two second fins 22 are mated together or have a small gap between two adjacent heat exchange tubes 11, and the inclined arrangement of the second fins 22 makes the horizontal mass transfer channel appear as a continuous corrugated shape. Multiple second fins 22 arranged sequentially along the first direction have interconnected through-holes 20a to form a vertical mass transfer channel. Since the second fins 22 are arranged at an angle between adjacent heat exchange tubes 11 and cover the vertical flow area, the gas and liquid phases flow upwards or downwards through the through-holes 20a on the second fins 22. The horizontal and vertical mass transfer channels together constitute the mass transfer channel for the gas and liquid phases to flow through.

[0069] Fourth embodiment: like Figures 9 to 12As shown, the difference between this embodiment and the third embodiment is that the fin units in the third embodiment are all of the same type, while this embodiment has two types of fin units, namely the first unit and the second unit. The second fins 22 in both fin units are arranged symmetrically, but the arrangement angle of the second fins 22 is different. Specifically, taking the example of both fin units having four second fins 22, the four second fins 22 in the first unit are evenly distributed along the circumference, while the four second fins 22 in the second unit are arranged in a bilateral symmetrical manner, that is, two second fins 22 are concentrated on each side. From the axial projection direction, the two second fins 22 of the second unit are exactly located between the two adjacent second fins 22 of the first unit in the circumferential direction. The two fin units are arranged alternately along the axial direction, thereby continuously disrupting the axial flow structure of the fluid and significantly enhancing the turbulence and gas-liquid mixing effect. The second fins 22 are arranged at an angle between two adjacent heat exchange tubes 11, defining a vertical mass transfer channel and a horizontal mass transfer channel. The horizontal mass transfer channel presents a continuous corrugated shape due to the inclined arrangement of the second fins 22. Because this embodiment has two finned units, the resulting gas-liquid flow is more tortuous, which increases the frequency of gas-liquid contact, enhances turbulence, and improves mass transfer and heat exchange compared to the third embodiment.

[0070] In the first to fourth embodiments described above, the through holes 20a provided in the finned unit can be arranged in a straight line or in a regular staggered arrangement. The staggered arrangement can change the flow direction of the process fluid, thereby achieving thorough mixing and improving the efficiency of mass transfer and heat exchange. When the structured packing 100 is installed in the absorption tower, the multiple heat exchange tubes 11 are horizontal, with one end of the multiple heat exchange tubes 11 serving as the inlet end of the cooling medium and the other end serving as the outlet end of the cooling medium. The cooling medium enters from the inlet end, flows along the inner cavity of the heat exchange tube 11, and exits from the outlet end. During operation, the flue gas flows upward through the corrugated channel formed by the fins, and the absorbent forms a liquid film on the fin surface from top to bottom and flows downward. The cooling medium enters the inlet end of all heat exchange tubes 11 and flows towards the outlet end. During the flow, heat is transferred from the gas-liquid mixture to the cooling medium through the fins and tube walls.

[0071] The structured packing 100 described in the above embodiments is relatively easy to manufacture and assemble. For the structured packing 100 with fins arranged in a straight line, its flow channels are relatively straight, which makes it easy to clean and maintain. Of course, although the staggered arrangement of fins is not easy to clean, it also improves the efficiency of mass transfer and heat transfer by increasing the tortuosity and complexity of the flow channels.

[0072] Besides the arrangement provided in the above embodiments, in the layered structure, multiple heat exchange tubes 11 within the same packing unit layer, i.e., multiple heat exchange tubes 11 arranged sequentially at intervals along the second direction, can be arranged at the same angle or at an offset angle. Similarly, two heat exchange tubes 11 in adjacent packing unit layers, i.e., two adjacent heat exchange tubes 11 along the first direction, can be arranged at the same angle or at an offset angle. The offset angle arrangement of the heat exchange tubes 11 also results in the finned units mounted on them being arranged at an offset angle. By rotating the heat exchange tubes 11 by a specific angle, the finned units fixed to the outer wall of the heat exchange tubes 11 are offset at a certain angle, thereby forming a rotating fin array or a spiral fin array. This offset angle arrangement can increase the tortuosity and complexity of the flow channel.

[0073] Fifth embodiment (not shown in the figure): Multiple heat exchange tubes 11 are arranged vertically to form the skeleton structure of the structured packing 100. Specifically, the multiple vertical heat exchange tubes 11 are arranged in several concentric rings around the center of the absorption tower. Each concentric ring is a ring-shaped packing layer, and multiple ring-shaped packing layers are connected into one unit by the support member 30. The heat exchange tubes 11 are welded perpendicularly to the fins, that is, the fins are parallel to the cross-section of the absorption tower, so that gas and liquid can pass through the fins. The through holes 20a on the fins can be arranged in a straight line or staggered.

[0074] To increase the coverage area of ​​the fins on the tower cross section and thus improve the mass transfer and heat exchange effect, the fins along the length of the heat exchange tube 11 and located in adjacent layers can be arranged at the same angle or at an angled offset. By offsetting the arrangement to break the symmetry, the fluid is forced to mix in the radial and circumferential directions, which greatly improves the problem of uneven distribution. The structural asymmetry is used to improve the fluid distribution, thereby improving the performance of large equipment.

[0075] In this embodiment, when the structured packing 100 is installed inside the absorption tower, multiple heat exchange tubes 11 are arranged vertically. The gas and liquid phases flow within the tortuous channel formed by the fins and the outer wall of the heat exchange tubes 11, and are continuously mixed and agitated due to the rotating arrangement of the fins. Simultaneously, the refrigerant flows within the circumferentially distributed heat exchange tubes 11, uniformly covering the entire tower cross-section, achieving a highly efficient and uniform heat exchange process. This arrangement is suitable for large-diameter absorption towers, offering advantages such as good radial mixing, uniform temperature and concentration fields, and high mass transfer and heat exchange efficiency.

[0076] In this embodiment, multiple annular horizontal mass transfer channels are formed between two adjacent annular packing layers, arranged along the length of the heat exchange tube 11. These horizontal mass transfer channels are defined by multiple fins on each annular packing layer. Through-holes 20a on the multiple fins arranged sequentially along the length of the heat exchange tube 11 are interconnected to form vertical mass transfer channels. Since the fins cover the flow area of ​​both gas and liquid phases, the gas and liquid phases flow upwards or downwards through the through-holes 20a on the fins. The horizontal and vertical mass transfer channels together constitute the mass transfer channels through which the gas and liquid phases flow.

[0077] The present invention also proposes an absorption tower (not shown in the figure), the absorption tower having a packing layer inside, the packing layer including at least one structured packing 100, the specific structure of the structured packing 100 being as described in the above embodiments. Since the absorption tower adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0078] The structured packing 100 provided in this invention is designed for use in chemical unit operations requiring both efficient mass transfer and timely heat removal. This packing is particularly suitable for highly exothermic processes such as CO2 chemical absorption, chemical distillation, and reactive distillation. The fundamental objective of this invention is to solve a series of problems caused by the accumulation of reaction heat in existing technologies, including decreased absorption rate, increased solvent circulation volume, increased regeneration energy consumption, and bulky equipment. By integrating a heat exchange structure into the structured packing 100, in-situ and efficient removal of reaction heat is achieved, ultimately realizing the comprehensive goal of improving the economy, compactness, and operational stability of the entire process.

[0079] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0080] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0081] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0082] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A structured packing for use in an absorption tower, characterized in that, The structured packing includes: A heat exchange tube assembly (10) includes multiple heat exchange tubes (11) for circulating a cooling medium. A finned assembly for contacting process fluids and comprising multiple finned units mounted on the outer wall of the heat exchange tube (11); The multiple fin units can collectively define multiple vertical mass transfer channels and multiple horizontal mass transfer channels, and the vertical mass transfer channels and the horizontal mass transfer channels are interconnected.

2. The structured packing according to claim 1, characterized in that, The structured packing has a layered structure and includes multiple packing unit layers arranged in parallel and spaced apart along the first direction. The multiple packing unit layers are connected into one unit by a support member (30). The packing unit layer includes a plurality of heat exchange tubes (11) arranged in parallel and spaced apart along the second direction, and the heat exchange tubes (11) extend along the third direction.

3. The structured packing according to claim 2, characterized in that, The first direction, the second direction, and the third direction are all perpendicular to each other.

4. The structured packing according to claim 3, characterized in that, The finned unit is a first fin (21) and is connected between two adjacent heat exchange tubes (11) of the packing unit layer. The first fin (21) has multiple through holes (20a). The through holes (20a) on the plurality of first fins (21) arranged sequentially along the first direction are interconnected to form the vertical mass transfer channel; The interlayer gap between any two adjacent packing unit layers forms the horizontal mass transfer channel.

5. The structured packing according to claim 4, characterized in that, The through holes (20a) of two adjacent first fins (21) along the first direction are staggered.

6. The structured packing according to claim 4, characterized in that, The first fin (21) extends in a wavy shape along the second direction.

7. The structured packing according to claim 3, characterized in that, The finned unit includes a plurality of second fins (22) symmetrically arranged on the outer wall of the heat exchange tube (11), and the second fins (22) are provided with a plurality of through holes (20a); The through holes (20a) on the plurality of second fins (22) arranged sequentially along the first direction are interconnected to form the vertical mass transfer channel; The two adjacent packing unit layers are interconnected through the through holes (20a) on the second fin (22) to form the horizontal mass transfer channel.

8. The structured packing according to claim 7, characterized in that, Multiple finned units are staggered along the extension direction of the heat exchange tube (11); And / or, two adjacent fin units along the first direction are arranged at an angular offset.

9. The structured packing according to claim 1, characterized in that, The structured packing is a ring-shaped layered structure and includes multiple ring-shaped packing layers arranged concentrically. Each ring-shaped packing layer includes multiple heat exchange tubes (11) arranged circumferentially. The multiple ring-shaped packing layers are connected into one unit by a support member (30).

10. The structured packing according to any one of claims 1 to 9, characterized in that, The heat exchanger tube assembly (10) also includes: A distributor for connecting to the inlet ends of the plurality of heat exchange tubes (11); A collector for connecting to the outlet ends of the plurality of heat exchange tubes (11).

11. An absorption tower, wherein the interior of the absorption tower is provided with a packing layer, characterized in that, The packing layer comprises at least one structured packing according to any one of claims 1 to 10.

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