Falling film tube and falling film tube absorber

Abstract

The invention relates to the technical field of heat exchange equipment, in particular to a falling film tube and a falling film tube absorber, the falling film tube comprises a tube body, a plurality of upper protrusions and a plurality of lower protrusions, the upper protrusions and the lower protrusions are arranged on the outer wall face of the tube body, the upper protrusions and the lower protrusions are alternately arranged at intervals in the axis direction of the tube body, and the upper protrusions and the lower protrusions are arranged on the outer wall face of the tube body. The upper protrusion and the lower protrusion are oppositely arranged in the radial direction of the pipe body, the upper protrusion and the lower protrusion are bent towards one end of the axis of the pipe body, and the size of the upper protrusion and the size of the lower protrusion in the radial direction of the pipe body range from 0.5 mm to 1 mm. According to the falling film tube, heat exchange liquid is drained, so that the heat exchange area is increased, the heat exchange time is prolonged, and the heat exchange efficiency is improved.

Description

Technical Field

[0001] This application is positioned in the technical field of heat exchange equipment, specifically relating to a falling film tube and a falling film tube absorber. Background Technology

[0002] Falling film absorbers, as highly efficient heat and mass transfer devices, play a vital role in seawater desalination, air conditioning and refrigeration, petrochemicals, and industrial waste heat utilization. These devices typically employ vertical or horizontal tube arrangements. Horizontal tube falling film absorbers, in particular, exhibit significant advantages such as high absorption efficiency, low pressure drop, and flexible operation and adjustment because their absorption process occurs not only in the liquid film region on the surface of the falling film tubes but also involves the absorption of solutions with various flow patterns between the tubes.

[0003] From a structural perspective, falling film absorbers belong to the wet-wall surface absorption device category, generally consisting of three parts: a liquid film distribution section, an absorption cooling section, and a gas-liquid separation section. Its core working mechanism involves the absorbent forming a thin film along the tube wall through the film distributor, undergoing mass transfer and reaction with the gas under co-current or counter-current conditions. The heat released during this process is carried away by the external cooling medium, allowing the absorption process to proceed under near-isothermal conditions, making it particularly suitable for gas absorption accompanied by high thermal effects. However, related technologies still face some key challenges in their development. The heat transfer coefficient of current falling film absorbers needs further improvement. More significantly, the solution wetting ability of the falling film tube is generally weak in both the circumferential and axial directions. This is mainly because in traditional designs, the liquid film relies primarily on gravity to flow rapidly down the tube wall, resulting in uneven liquid film distribution and high flow velocity, reducing the effective contact time between the gas and liquid phases, thus affecting the final absorption efficiency.

[0004] Fluoroplastic falling film tubes, as a novel falling film tube material, have received increasing attention in the field of falling film absorbers in recent years. Their emergence provides a new technical approach to address the shortcomings of traditional metal falling film tubes in terms of corrosion resistance and economic efficiency, especially demonstrating unique application potential in the absorption of highly corrosive media (such as chlorine-, sulfur-, or fluorine-containing gases) and in high-temperature and high-humidity environments. However, the hydrophobic nature of fluoroplastics presents unique wettability challenges for their application. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] Therefore, embodiments of the present invention propose a falling film tube, which increases the heat exchange area and heat exchange time by guiding the flow of heat exchange liquid, thereby improving heat exchange efficiency.

[0007] The falling film tube of this invention includes: a tube body, an upper protrusion and a lower protrusion. The upper protrusion and the lower protrusion are disposed on the outer wall surface of the tube body. There are multiple upper protrusions and lower protrusions. The upper protrusions and lower protrusions are arranged alternately and at intervals in the axial direction of the tube body, and the upper protrusions and lower protrusions are arranged opposite each other in the radial direction of the tube body. Both the upper protrusion and the lower protrusion are bent toward one end of the tube axis, and the dimensions of the upper protrusion and the lower protrusion in the radial direction of the tube are 0.5mm-1mm.

[0008] The falling film tube in the embodiments of the present invention increases the heat exchange area and heat exchange time by guiding the flow of heat exchange liquid, thereby improving heat exchange efficiency.

[0009] In some embodiments, the upper protrusion includes a first segment, an upper central segment, and a second segment. The first segment is connected to one end of the upper central segment, and the other end of the upper central segment is connected to the second segment. The end face of the upper central segment away from the tube body is a plane. The first segment and the second segment are spirally arranged on the tube body, and the spiral directions of the first segment and the second segment are opposite. The first segment and the second segment and the axis of the tube body both have a first preset spiral angle A, and 30°≤A≤60°.

[0010] In some embodiments, the plurality of upper protrusions have a first preset spacing in the direction of the tube axis, the first preset spacing being less than or equal to one-half of the radial dimension of the tube and greater than or equal to one-third of the radial dimension of the tube.

[0011] In some embodiments, the lower protrusion includes a third segment, a lower central segment, and a fourth segment. One end of the third segment is connected to one end of the lower central segment, and the other end of the lower central segment is connected to the fourth segment. The end face of the lower central segment away from the tube body is a plane. The third and fourth segments are spirally arranged on the tube body, and the spiral directions of the third and fourth segments are opposite. The third and fourth segments and the axis of the tube body each have a first preset helix angle B, and 30°≤B≤60°.

[0012] In some embodiments, the plurality of lower protrusions have a second preset spacing in the axial direction of the tube body, the second preset spacing being less than or equal to one-half and greater than or equal to one-third of the radial dimension of the tube body.

[0013] In some embodiments, the falling film tube includes a connecting ring, a spiral blade, and a limiting ring. The connecting ring and the limiting ring are rotatably disposed in the tube body. One end of the spiral blade is connected to the connecting ring, and the limiting ring is connected to the other end of the spiral blade. The spiral blade is spirally disposed in the axial direction of the tube body, and the connecting ring is disposed at one end of the tube body adjacent to the inlet.

[0014] In some embodiments, the falling film tube further includes a limiting protrusion disposed within the tube body. There are multiple limiting protrusions, which are spaced apart circumferentially on the inner wall of the tube body, and one end of the limiting protrusion away from the tube body outlet contacts the limiting ring.

[0015] In some embodiments, a third preset distance is provided between the limiting protrusion and the tube outlet, the third preset distance being greater than or equal to one-third of the tube length and less than or equal to three-quarters of the tube length.

[0016] The falling film absorber of this invention includes: a housing, the housing having an absorption chamber, the bottom of the housing having a flue gas inlet communicating with the absorption chamber and the top having a flue gas outlet communicating with the absorption chamber; The apparatus includes a connecting pipe, a spray pipe, and a falling film pipe, wherein the falling film pipe is any of the falling film pipes described above, a spray pipe is provided at the top of the absorption chamber, a plurality of falling film pipes are provided above the spray pipe, the falling film pipes are spaced apart in the vertical direction, a connecting pipe is provided between adjacent falling film pipes, one end of the connecting pipe is connected to one of the falling film pipes, and the other end of the connecting pipe is connected to another falling film pipe.

[0017] The falling film absorber of the present invention improves heat exchange efficiency by diverting the heat exchange liquid to increase the heat exchange area and heat exchange time.

[0018] In some embodiments, falling film tubes at the same height in the vertical direction constitute one layer, and at least three layers of falling film tubes are arranged alternately in the vertical direction. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a falling film tube according to an embodiment of the present invention.

[0020] Figure 2 This is a top view of the falling film tube according to an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the limiting protrusion in an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the falling film tubes arranged alternately inside the absorber according to an embodiment of the present invention.

[0023] Figure 5This is a schematic diagram of a falling film absorber according to an embodiment of the present invention.

[0024] Figure label: Tube body 1, Upper protrusion 2, first segment 21, upper central segment 22, second segment 23, Lower protrusion 3, third segment 31, fourth segment 33 4. Connecting ring; 5. Spiral blade; 6. Limiting ring; 7. Limiting protrusion. The shell is 10, the absorption chamber is 101, the spray pipe is 20, the falling film pipe is 30, and the connecting pipe is 40. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] The falling film tube 30 of this embodiment includes: The tube body 1, the upper protrusion 2 and the lower protrusion 3 are provided on the outer wall surface of the tube body 1. There are multiple upper protrusions 2 and lower protrusions 3. The upper protrusions 2 and lower protrusions 3 are arranged alternately in the axial direction of the tube body 1, and the upper protrusions 2 and lower protrusions 3 are arranged opposite each other in the radial direction of the tube body 1. Both the upper protrusion 2 and the lower protrusion 3 are bent towards one end of the axis of the tube body 1, and the radial dimensions of the upper protrusion 2 and the lower protrusion 3 in the tube body 1 are 0.5mm-1mm.

[0027] The falling film tube 30 in this embodiment of the invention increases the heat exchange area and heat exchange time by guiding the flow of heat exchange liquid, thereby improving heat exchange efficiency.

[0028] Specifically, such as Figures 1 to 5 As shown, the tube 1 is arranged in a horizontal direction, for example, in a front-to-back direction or in a left-to-right direction. For ease of description, this application takes a left-to-right arrangement as an example. The outer circumferential surface of the tube 1 is provided with an upper protrusion 2 and a lower protrusion 3. The upper protrusion 2 is located at the upper end of the outer circumferential surface of the tube 1, and the lower protrusion 3 is located at the bottom of the tube 1. When the solution drips into the falling film tube 30, it first contacts the uppermost upper protrusion 2. After contact with the upper protrusion 2, it slows down and initially disperses the solution, increases the flow path of the solution on the outer wall of the tube 1, reduces the velocity, and increases the heat exchange time. The solution on the outer wall and the cooling water in the tube 1 exchange heat through the tube wall.

[0029] Then, guided by the lower protrusion 3, similar liquids converge and drip, increasing the number of solution drop points, allowing the solution to spread out in the circumferential and axial directions of the falling film tube 30 to cover a larger area, increasing the gas-liquid contact time of the lower falling film tube 30, and improving heat exchange efficiency.

[0030] The upper protrusion 2 and the lower protrusion 3 are alternately spaced in the axial direction of the tube body 1, for example, alternately spaced in the left-right direction and spaced in the radial direction of the tube body 1. The upper protrusion 2 and the lower protrusion 3 bend in the same direction, for example, to facilitate the flow of liquid guided by the upper protrusion 2 to the lower protrusion 3 for further guidance and collection. Increasing the number of solution drop points allows the solution to spread out in the circumferential and axial directions of the falling film tube 30 to cover a larger area and increase the gas-liquid contact time.

[0031] In other words, the design of the upper protrusion 2 and the lower protrusion 3 allows the solution to spread out circumferentially and axially in the falling film tube 30, covering a larger area. This helps to increase the gas-liquid contact time and improve the heat exchange efficiency. The dimensions of the upper protrusion 2 and the lower protrusion 3 in the radial direction of the tube body 1 are 0.5mm-1mm, so as to avoid the tube body 1 and the protrusion arrangement being too thick and affecting heat exchange, and to meet a certain flow guiding effect.

[0032] It should be noted that the tube body 1, as well as the upper protrusion 2 and lower protrusion 3, are all made of polymer materials, such as fluoroplastics, and the tube body 1 is integrally molded with the upper protrusion 2 and lower protrusion 3 to reduce manufacturing costs and increase structural strength. In the falling film tube 30 of this embodiment, the upper protrusion 2 acts as a decelerator when the solution comes into contact with it, slowing down the falling speed of the solution. This helps to prolong the contact time between the solution and the tube wall, increasing the heat exchange time. Alternatively, the upper protrusion 2 helps to disperse the solution, allowing it to be more evenly distributed on the tube wall instead of flowing directly down. This helps to improve the uniformity of heat exchange. By guiding and decelerating the heat exchange liquid, the heat exchange area and heat exchange time are increased, thereby improving the heat exchange efficiency. The lower protrusion 3 collects the liquid flowing down from the upper protrusion 2, increasing the liquid coverage area on the tube wall and increasing the number of liquid drop points, allowing the liquid to be more evenly distributed on the tube wall. The protrusion can guide the liquid to flow along a specific path, optimizing the liquid flow on the tube wall. The lower protrusion 3 helps to prolong the residence time of the liquid on the tube wall, increasing the gas-liquid contact time, thereby improving the heat exchange efficiency.

[0033] In some embodiments, the upper protrusion 2 includes a first segment 21, an upper central segment 22, and a second segment 23. The first segment 21 is connected to one end of the upper central segment 22, and the other end of the upper central segment 22 is connected to the second segment 23. The end face of the upper central segment 22 away from the tube body 1 is a plane. The first segment 21 and the second segment 23 are spirally arranged on the tube body 1, and the spiral directions of the first segment 21 and the second segment 23 are opposite. The first segment 21 and the second segment 23 both have a first preset spiral angle A with the axis of the tube body 1, and 30°≤A≤60°.

[0034] Specifically, such as Figures 1 to 5As shown, the upper protrusion 2 includes a central upper section 22 and a first section 21 and a second section 23 on the front and rear sides. The central upper section 22 is located at the top, and its lower end is connected to the tube body 1. The upper surface of the central upper section 22 is flat, increasing the contact area between the upper protrusion 2 and the solution, thus enhancing the drainage and deceleration effects. The first section 21 and the second section 23 have the same spiral direction, thereby achieving the bending of the upper protrusion 2. This allows the liquid to flow from both the front and rear sides when it drips onto the upper protrusion 2, dispersing and decelerating the liquid. The first section 21 and the second section 23 further disperse and guide the liquid, increasing the liquid flow range. This increases the heat exchange area and heat exchange time, thereby improving the heat exchange efficiency. By setting the helix angle, it is helpful to control the flow path of the liquid, so that it covers the surface of the tube 1 more evenly. An appropriate helix angle can increase the turbulence effect when the liquid flows, which helps to increase the contact frequency between the liquid and the surface of the tube 1. The helix angle also helps to prolong the contact time of the liquid on the surface of the tube 1, because the liquid needs to flow a longer distance along the helix path to reach the lower protrusion 3 or the bottom of the tube 1. By increasing the contact time and turbulence effect, the overall heat exchange efficiency is improved.

[0035] In some embodiments, the plurality of upper protrusions 2 have a first preset spacing in the axial direction of the tube body 1. The first preset spacing is less than or equal to half of the radial dimension of the tube body 1 and greater than or equal to one-third of the radial dimension of the tube body 1.

[0036] By setting the first preset spacing range, the liquid is ensured to have sufficient and uniform coverage on the surface of the tube 1, and the liquid forms a good flow pattern on the surface of the tube 1, thereby enhancing the fluid dynamics effect, promoting the dispersion and deceleration of the liquid, increasing the contact time with the surface of the tube 1, and improving the heat exchange time.

[0037] By setting the size of the first preset spacing, excessively large spacing between the upper protrusions 2 can be avoided, which would cause liquid to accumulate in certain areas and affect the heat exchange effect. Conversely, excessively small spacing can also reduce the possibility of liquid accumulation and increase resistance to liquid flow. By setting an appropriate first preset spacing, heat exchange efficiency can be maintained while reducing flow resistance and improving heat exchange stability. At the same time, excessively small spacing between the upper protrusions 2 can be avoided, which would increase the overall thickness of the falling film tube 30 and affect heat exchange. By setting the size of the first preset spacing, the thickness of the overall falling film tube 30 is kept within a preset range, improving the stability of the heat exchange efficiency during operation of the falling film tube 30.

[0038] In some embodiments, the lower protrusion 3 includes a third segment 31, a lower central segment, and a fourth segment 33. One end of the third segment 31 is connected to one end of the lower central segment, and the other end of the lower central segment is connected to the fourth segment 33. The end face of the lower central segment away from the tube body 1 is a plane. The third segment 31 and the fourth segment 33 are spirally arranged on the tube body 1, and the spiral directions of the third segment 31 and the fourth segment 33 are opposite. The third segment 31 and the fourth segment 33 both have a first preset helix angle B with the axis of the tube body 1, and 30°≤B≤60°.

[0039] Specifically, such as Figures 1 to 5 As shown, the lower central section is located at the bottom, and its upper end is connected to the tube body 1. The lower end face of the lower central section is flat to weaken the droplet aggregation effect and increase the number of solution droplet points, so that the other falling film tubes 30 below can receive the uniformly falling liquid and improve the heat exchange efficiency. The spiral directions of the third section 31 and the fourth section 33 are the same, thus realizing the bending of the lower protrusion 3. The upper protrusion 2 and the lower protrusion 3 bend in the same direction, so that when the liquid flows to the lower protrusion 3, after the liquid flows from the upper protrusion 2 to the lower protrusion 3, the liquid bends from top to bottom, increasing the flow path and reducing the liquid velocity, thereby increasing the liquid flow range.

[0040] It should be noted that the extension angles of the upper protrusion 2 and the lower protrusion 3 remain the same, that is, the helix angles on the same side are the same. For example, the third segment 31 is on the same side of the first segment 21 in the front-back direction, the second segment 23 is on the same side of the fourth segment 33 in the front-back direction, the first segment 21 and the third segment 31 have the same helix angle, and the fourth segment 33 and the second segment 23 have the same helix angle. The lower protrusion 3 extends from bottom to top, with its starting point aligned with the ending point of the upper protrusion 2. For example, the uppermost point of the fourth segment 33 is opposite to the lowermost point of the first segment 21, and the uppermost point of the third segment 31 is opposite to the lowermost point of the second segment 23. This causes the liquid to flow in a bent manner from the upper protrusion 2 to the lower protrusion 3, extending the liquid flow path, or in other words, increasing the displacement of the heat exchange path.

[0041] In some embodiments, the plurality of lower protrusions 3 have a second preset spacing in the axial direction of the tube body 1, the size of the second preset spacing being less than or equal to one-half and greater than or equal to one-third of the radial dimension of the tube body 1.

[0042] Specifically, such as Figures 1 to 5 As shown, by setting the second preset spacing of the lower protrusion 3 in the axial direction of the tube body 1, the solution is uniformly distributed and flows on the tube body 1, which promotes the flow of the solution on the surface of the tube body 1, improves the heat exchange efficiency, avoids the formation of stagnant areas of liquid on the surface of the tube body 1, and reduces the risk of dirt and scale.

[0043] In some embodiments, the falling film tube 30 includes a connecting ring 4, a spiral blade 5, and a limiting ring 6. The connecting ring 4 and the limiting ring 6 are rotatably disposed inside the tube body 1. One end of the spiral blade 5 is connected to the connecting ring 4, and the limiting ring 6 is connected to the other end of the spiral blade 5. The spiral blade 5 is spirally disposed in the axial direction of the tube body 1, and the connecting ring 4 is disposed at one end of the tube body 1 adjacent to the inlet.

[0044] Specifically, such as Figures 1 to 5 As shown, the left end of pipe body 1 is the outlet of pipe body 1, and the right end of pipe body 1 is the inlet of pipe body 1. The upper protrusion 2 and the lower protrusion 3 bend to the right. The connecting ring 4 is located inside the pipe body 1, and the connecting ring 4 is located at one end adjacent to the inlet of the pipe body 1, that is, at the right end.

[0045] The spiral blade 5 is spirally arranged in the left and right directions. The left end of the spiral blade 5 is connected to the limiting ring 6, and the right end of the spiral blade 5 is connected to the connecting ring 4. The spiral blade 5 can rotate inside the pipe body 1. For example, when the spiral blade 5 is impacted by the liquid flowing inside the pipe body 1, the spiral blade 5 rotates. The turbulence assembly composed of the annular connecting ring 4, the limiting ring 6, and the spiral turbulence plate generates rotation and micro-vibration under the action of the liquid flow inside the pipe body 1, so as to mix and exchange the fluid in the upper half and the lower half of the pipe body 1.

[0046] This implementation, by setting up spiral blades 5, avoids the liquid flow in the tube 1 concentrating in the lower part of the falling film tube 30 and the upper part not having heat exchange contact. Through the rotation of spiral blades 5, the thermal boundary layer inside the tube is effectively broken and the bottom steady flow area is disturbed, increasing the actual contact area between the liquid and the inner wall of the tube, thereby significantly improving the heat exchange efficiency, ensuring the heat released during the absorption process is discharged, and enhancing the overall heat and mass transfer performance and operational stability of the equipment.

[0047] In some embodiments, the falling film tube 30 further includes a limiting protrusion 7, which is disposed inside the tube body 1. There are multiple limiting protrusions 7, which are arranged circumferentially on the inner wall surface of the tube body 1. The end of the limiting protrusion 7 away from the outlet of the tube body 1 is in contact with the limiting ring 6.

[0048] Specifically, such as Figures 1 to 5 As shown, the limiting protrusion 7 is located at the left end of the limiting ring 6. For example, the limiting protrusion 7 is located in the middle of the left-right direction of the pipe body 1, and the limiting protrusion 7 is closer to the outlet of the pipe body 1 than the limiting ring 6. When the liquid in the pipe body 1 impacts the spiral blade 5, the spiral blade 5 drives the limiting ring 6 to move to the left. At this time, the limiting protrusion 7 is suitable for limiting the movement range of the limiting ring 6 and the spiral blade 5. When the liquid in the pipe body 1 impacts the spiral blade 5, the spiral blade 5 drives the limiting ring 6 to move to the left. The limiting protrusion 7 limits the movement range of the limiting ring 6 and the spiral blade 5, preventing excessive movement from causing equipment damage and improving the stability of equipment operation.

[0049] In some embodiments, a third preset distance is provided between the limiting protrusion 7 and the outlet of the tube body 1. The third preset distance is greater than or equal to one-third of the length of the tube body 1 and less than or equal to three-quarters of the length of the tube body 1.

[0050] Specifically, such as Figures 1 to 5As shown, the third preset distance between the limiting protrusion 7 and the outlet of the pipe body 1 is greater than or equal to one-third and less than or equal to three-quarters of the length of the pipe body 1, so as to provide sufficient space inside the pipe body 1 to control the fluid flow. For example, the fluid, after being disturbed by the spiral blades 5, flows stably through the area where the spiral blades 5 are not set when approaching the outlet, reducing flow resistance and improving heat exchange efficiency. This allows for the use of spiral blades 5 of different lengths according to specific heat exchange requirements or different types of solutions sprayed by the spray pipe 20 to achieve the best heat exchange effect, thereby improving the energy efficiency of the entire system.

[0051] The falling film absorber of this invention includes: The housing 10 has an absorption chamber 101, a flue gas inlet at the bottom communicating with the absorption chamber 101, and a flue gas outlet at the top communicating with the absorption chamber 101. The absorption chamber 101 is provided with a top spray pipe 20 and a multiple falling film pipes 30 above the spray pipe 20. The falling film pipes 30 are spaced apart in the vertical direction. A connecting pipe 40 is provided between adjacent falling film pipes 30. One end of the connecting pipe 40 is connected to one of the falling film pipes 30 and the other end of the connecting pipe 40 is connected to another falling film pipe 30.

[0052] The falling film tube 30 in this embodiment of the invention increases the heat exchange area and heat exchange time by guiding the flow of heat exchange liquid, thereby improving heat exchange efficiency.

[0053] Specifically, such as Figures 1 to 5 As shown, the falling film tubes 30 inside the housing 10 are arranged at intervals in the vertical direction and at the same height. There can be multiple falling film tubes 30, which are connected sequentially in the vertical direction. For example, they can be connected by existing connecting hoses, or the housing 10 can be integrated with a connecting pipe 40. The spray pipe 20 is set at the top to spray the solution. The solution flows out from the bottom of the falling film absorber. The flue gas enters from the bottom of the absorption chamber 101 and flows out from the top. The liquid sprayed by the spray pipe 20 exchanges heat with the flue gas. Then, the liquid after heat exchange exchanges heat with the fluid in the falling film tube 30 to realize the waste heat recovery of the flue gas.

[0054] The falling film tube 30 in this embodiment of the invention, by setting up the falling film tube 30, and the upper protrusion 2 and lower protrusion 3 on the falling film tube 30 to guide the flow of heat exchange liquid, increases the heat exchange area and heat exchange time, thereby improving heat exchange efficiency. Compared with the packed absorbers or absorption towers in the prior art, the falling film tube 30 is arranged at intervals in both the horizontal and vertical directions to reduce the pressure loss of flue gas. Furthermore, it avoids the flow dead zones caused by the packing, improving heat exchange efficiency and heat exchange stability.

[0055] In some embodiments, falling film tubes 30 at the same height in the vertical direction constitute one layer, and at least three layers of falling film tubes 30 are arranged alternately in the vertical direction. The horizontal direction can be understood as the left-right direction or the front-back direction, or the plane enclosed by the left-right direction and the front-back direction, and the falling film tubes 30 in the same layer are arranged in parallel.

[0056] Specifically, such as Figures 1 to 5 As shown, the falling film tubes 30 are multi-layered in the vertical direction, with at least one falling film tube 30 in each layer. The layer closest to the spray pipe 20 is the first layer, the next closest layer is the second layer, and the falling film tubes 30 further away are the third layer, and so on.

[0057] The first layer of falling film tubes 30 are arranged at intervals in the horizontal direction. A second layer of falling film tubes 30 is positioned directly below the area between two falling film tubes 30 in the first layer. The second layer of falling film tubes 30 is positioned directly above the area between two falling film tubes 30 in the third layer. This staggered arrangement of the falling film tubes 30 across the first three layers, with the vertical intervals remaining constant, ensures that the second layer effectively contacts the splashing liquid along the tangential direction of the first layer, increasing the liquid coverage of the second layer. From the third layer onwards, the flow velocity decreases significantly after passing through the first two rows of buffers, reducing splashing. A conventional parallel arrangement can be used; for example, the fourth layer of falling film tubes 30 can be arranged vertically and parallel to the third layer of falling film tubes 30.

[0058] This embodiment optimizes liquid distribution, reduces splashing and droplet carryover, and lowers flow velocity and pressure drop through the staggered arrangement of the top three layers of falling film tubes 30. Simultaneously, it avoids excessive flue gas pressure loss caused by the staggered arrangement of multiple layers of falling film tubes 30, thereby improving heat exchange efficiency and operational stability. In the description of this invention, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0059] Furthermore, 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0060] In this invention, unless otherwise explicitly 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 them; 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 explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0062] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. 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.

[0063] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A falling film tube, characterized in that include: The tube body, upper protrusion and lower protrusion are provided on the outer wall surface of the tube body. There are multiple upper protrusions and lower protrusions. The upper protrusions and lower protrusions are arranged alternately and at intervals in the axial direction of the tube body, and the upper protrusions and lower protrusions are arranged opposite each other in the radial direction of the tube body. Both the upper protrusion and the lower protrusion are bent toward one end of the tube axis, and the dimensions of the upper protrusion and the lower protrusion in the radial direction of the tube are 0.5mm-1mm.

2. The falling film tube according to claim 1, characterized in that The upper protrusion includes a first segment, an upper central segment, and a second segment. The first segment is connected to one end of the upper central segment, and the other end of the upper central segment is connected to the second segment. The end face of the upper central segment away from the tube body is a plane. The first segment and the second segment are spirally arranged on the tube body, and the spiral directions of the first segment and the second segment are opposite. The first segment and the second segment and the axis of the tube body both have a first preset spiral angle A, and 30°≤A≤60°.

3. The falling film tube according to claim 2, characterized in that, The plurality of upper protrusions have a first preset spacing in the direction of the tube axis, the first preset spacing being less than or equal to one-half of the radial dimension of the tube and greater than or equal to one-third of the radial dimension of the tube.

4. The falling film tube according to claim 1, characterized in that, The lower protrusion includes a third segment, a lower central segment, and a fourth segment. One end of the third segment is connected to one end of the lower central segment, and the other end of the lower central segment is connected to the fourth segment. The end face of the lower central segment away from the tube body is a plane. The third and fourth segments are spirally arranged on the tube body, and the spiral directions of the third and fourth segments are opposite. The third and fourth segments and the axis of the tube body each have a first preset helix angle B, and 30°≤B≤60°.

5. The falling film tube according to claim 4, characterized in that, The plurality of lower protrusions have a second preset spacing in the direction of the tube axis, the second preset spacing being less than or equal to one-half and greater than or equal to one-third of the radial dimension of the tube.

6. The falling film tube according to claim 1, characterized in that, It also includes a connecting ring, a spiral blade, and a limiting ring. The connecting ring and the limiting ring are rotatably disposed in the tube body. One end of the spiral blade is connected to the connecting ring, and the limiting ring is connected to the other end of the spiral blade. The spiral blade is spirally disposed in the axial direction of the tube body, and the connecting ring is disposed at one end of the tube body near the inlet.

7. The falling film tube according to claim 6, characterized in that, It also includes a limiting protrusion, which is disposed in the tube body. There are multiple limiting protrusions, which are arranged at intervals in the circumferential direction on the inner wall of the tube body, and the end of the limiting protrusion away from the tube body outlet is in contact with the limiting ring.

8. The falling film tube according to claim 7, characterized in that, A third preset distance is provided between the limiting protrusion and the tube outlet, the third preset distance being greater than or equal to one-third of the tube length and less than or equal to three-quarters of the tube length.

9. A falling film absorber, characterized in that, include: The housing has an absorption chamber, and the bottom of the housing is provided with a flue gas inlet communicating with the absorption chamber and the top of the housing is provided with a flue gas outlet communicating with the absorption chamber. The apparatus includes a connecting pipe, a spray pipe, and a falling film pipe, wherein the falling film pipe is any of the falling film pipes described above. A spray pipe is provided at the top of the absorption chamber, and multiple falling film pipes are provided above the spray pipe. The falling film pipes are spaced apart in the vertical direction. A connecting pipe is provided between adjacent falling film pipes, with one end of the connecting pipe connected to one of the falling film pipes and the other end of the connecting pipe connected to another falling film pipe.

10. The falling film absorber according to claim 9, characterized in that, include: Falling film tubes at the same height in the vertical direction constitute one layer, and at least three layers of falling film tubes are arranged alternately in the vertical direction.

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