A bundled plate air preheater

Abstract

This invention discloses a clustered plate air preheater to solve the problems of low heat exchange efficiency and large temperature difference at the hot end in existing air preheaters with direct flue gas-air heat exchange. The clustered plate air preheater mainly consists of a shell, clustered plates, a flow guide tube, and inner baffles. The shell contains N sets of parallel-arranged clustered plates, each set of which is covered by a flow guide tube in the middle section. There are three inner baffles, all arranged perpendicular to the clustered plates, dividing the clustered plates into two sections and thus dividing the shell into two shell-side sections. The clustered plates mainly consist of a fixed-end tube sheet, a free-end tube sheet, binding straps, multiple tube-plate type 1 tubes, one tube-plate type 2 tube, and an expansion joint. Tube-plate type 1 and tube-plate type 2 tubes are arranged parallel to each other and have the same length. They are stacked and combined into one unit by multiple binding straps. One end of tube-plate type 1 and tube-plate type 2 tubes is connected to the fixed-end tube sheet, and the other end is connected to the free-end tube sheet. Using this invention, the tube side and shell side can be flexibly selected; air can flow through the tube side and flue gas through the shell side, or flue gas can flow through the tube side and air through the shell side.

Description

Technical Field

[0001] This invention relates to the field of air preheater technology, and particularly to a plate-type air preheater. Background Technology

[0002] Air preheaters, as energy-saving devices, are widely used in waste heat recovery systems of flame-heated furnaces in the petrochemical industry, playing an important role in improving the thermal efficiency of flame-heated furnaces and saving energy.

[0003] A plate air preheater is a compact, high-efficiency air-to-air heat exchanger made of stacked identical thin metal plates with cold and hot fluid channels spaced apart, exchanging heat through the plates.

[0004] Plate air preheaters are structurally divided into welded and non-welded types. Plates serve as heat transfer elements, with two plates assembled into a plate tube. A certain number of plate tubes are stacked into a plate bundle, and flue gas and air exchange heat through the plates. The heat exchange elements are made of carbon steel, stainless steel, or higher-grade materials.

[0005] With the deepening of energy conservation and emission reduction, the flue gas temperature of flame-heated furnaces is constantly decreasing, and the flue gas temperature is trending down to below 90℃. Therefore, the metal at the tail end of the cryogenic air preheater faces a serious dew point corrosion problem.

[0006] Reference 1, "Heat Transfer Analysis of PTFE Plastic Air Preheater" (Jia Li, Chen Tiebing, et al., Journal of Beijing Institute of Civil Engineering and Architecture, 1999(Z1):1-7), introduces a novel corrosion-resistant plastic air preheater that can operate in high flue gas temperatures and acidic environments. This novel PTFE plastic air preheater is an axial-flow spiral plate heat exchanger, where air and flue gas flow separately within the jacket for heat exchange through the interlayer walls. However, unlike traditional spiral plate heat exchangers, the two heat exchange media do not flow in the same way; instead, they enter from opposite ends of the heat exchanger, performing co-current or counter-current heat exchange. This flow pattern requires a specially designed end cap to separate the flue gas and air. This design achieves modularity and low resistance in the heat exchanger, allowing the heat exchanger shell to be used as a single unit, and can be connected in series axially or in parallel with multiple channels as needed.

[0007] Reference 1 proposes using the heat exchanger shell as a unit, which can be used in axial series or in parallel with multiple channels as needed. However, the axial flow spiral plate heat exchanger it proposes requires a specially designed end cap to separate flue gas and air. The sealing between flue gas and air is not easy to solve. Therefore, this type of PTFE plastic plate air preheater has not been widely adopted.

[0008] Reference 2, "Research and Application of Large Fluoroplastic-Graphite Plate Heat Exchanger" (Liu Gang, Petrochemical Equipment, 2006(06):63-66), describes a large fluoroplastic-graphite plate heat exchanger that uses herringbone corrugated plates made of non-metallic materials such as fluoroplastics and graphite as heat transfer elements. It employs a line-surface combined sealing structure, using fixed end plates and bolts as fasteners, and compression springs and movable end plates as adjusting components to alleviate stress damage caused by contraction and expansion between the plates. This fluoroplastic-graphite plate heat exchanger has been used in various corrosive media without corrosion, demonstrating extremely strong corrosion resistance.

[0009] The heat exchanger proposed in Reference 2 combines the excellent properties of fluoroplastics and graphite, exhibiting high thermal conductivity and mechanical strength, as well as excellent corrosion resistance. However, the herringbone corrugated plates made of non-metallic materials such as fluoroplastics and graphite proposed in Reference 2 have a structure similar to the metal plates of an Alfa Laval plate heat exchanger. The plates have holes, making them suitable for heat exchange between liquids but unsuitable for gas-to-gas heat exchange between flue gas and air.

[0010] Patent CN 1276515A discloses a manufacturing process for a polytetrafluoroethylene (PTFE) plate-fin heat exchanger. The plate-fin heat exchanger is made of graphite-modified carbon fiber reinforced PTFE or PTFE, and has a series of advantages such as good corrosion resistance, high heat transfer efficiency, compact structure, and low cost.

[0011] However, in Patent 1, the core, composed of parts such as seals, fins, partitions, and cover plates, is sintered as a whole in a furnace and then bonded together after cooling. Therefore, it's impossible to check whether the internal fins deform after sintering. Furthermore, no case studies have been reported regarding the performance of this PTFE plate-fin heat exchanger.

[0012] Patent CN 100507426C discloses a compact plate-and-shell heat exchanger made of thermally conductive composite material, comprising a shell, a core, and a sealing plate. The core includes partitions, fins, and a sealing strip. Fins are provided between adjacent partitions, and the fins include metal fins and corrosion-resistant thermally conductive composite material fins. The metal fins and corrosion-resistant thermally conductive composite material fins are alternately arranged. A sealing strip is also provided between the corrosion-resistant thermally conductive composite material fins and the shell. In this invention, the metal fins and corrosion-resistant fins are alternately arranged. The channels of the corrosion-resistant fins carry corrosive and easily fouling media, while the channels of the metal fins carry a cleaner media. The two media form a complete countercurrent heat exchange, ensuring high heat exchange efficiency.

[0013] However, in Patent 2, the sealing plate and the partition, the partition and the fins, and the partition and the sealing strip are bonded with a fluorinated adhesive. When the heat exchanger operates in a high-temperature environment for a long time, the fluorinated adhesive is at risk of aging and losing its stickiness, which will lead to a decrease in the sealing performance of the heat exchanger or even cause leakage.

[0014] Patent CN 102032587B discloses a plate-type air preheater with glass heat exchange plates. The heat exchange plates are rectangular glass plates, made of borosilicate glass, boron-free low-alkali glass, or quartz glass. It has an air preheater frame consisting of an upper cover plate, a lower base plate, and columns. Several heat exchange plates are arranged vertically within the air preheater frame, with a sealing strip between each pair of adjacent plates. Specifically, a sealing strip is placed between the two ends of the lower heat exchange plate and the contact surface of the upper heat exchange plate. The sealing strips of adjacent layers are staggered by 90°, forming several adjacent, staggered, sealed fluid channels. These channels represent hot fluid channels and cold fluid channels, respectively. This glass plate heat exchanger is resistant to dew point corrosion and can achieve long-term stable operation in low-temperature flue gas environments, reducing exhaust gas temperature to below 100°C. Engineering applications of this glass plate air preheater demonstrate its strong corrosion resistance and excellent heat exchange performance.

[0015] However, in Patent 3, the glass plate air preheater is still the same as the traditional metal plate air preheater, with cross-flow heat exchange between flue gas and air, and does not achieve counter-flow heat exchange, so there is still room for improvement.

[0016] In summary, non-metallic plate air preheaters completely avoid the low-temperature dew point corrosion problem inherent in metal heat exchangers, and can reduce flue gas temperature to 80-90℃ or even lower, achieving deep recovery of flue gas waste heat. However, there are few reported cases of fluoroplastic plate air preheaters that directly exchange heat between flue gas and air. Although glass plate air preheaters provide relevant examples, their structure is similar to existing metal plate air preheaters, and problems such as low cross-flow heat exchange efficiency and large temperature difference at the hot end still exist. Summary of the Invention

[0017] Based on the aforementioned technical background, this invention proposes a clustered plate air preheater. This preheater employs clustered plates for counter-current air-flue gas heat exchange, addressing the problems of low cross-flow heat exchange efficiency, large hot-end temperature difference, and low-temperature dew point corrosion of metallic materials in existing plate air preheaters that rely on direct flue gas-air heat exchange. The heat transfer elements of this clustered plate air preheater are plates; two plates are assembled into a plate tube, and a certain number of plate tubes are stacked to form a clustered plate. Flue gas and air exchange heat through the plates. The plate material is flexible, allowing selection from metal and non-metal plates based on different flue gas temperatures. Stainless steel and carbon steel plates can be used for high- and medium-temperature air preheaters, while fluoroplastic plates, fluoroplastic-graphite plates, and glass plates can solve the dew point corrosion problem in low-temperature air preheaters. Furthermore, multiple sets of clustered plates are installed within the shell to achieve the required heat exchange area, enabling large-scale production. The clustered plates are modular, offering good independence, interchangeability, and versatility.

[0018] To achieve the above objectives, the technical solution of the present invention is as follows:

[0019] A cluster plate air preheater, characterized in that: the cluster plate air preheater mainly consists of a shell, cluster plates, a guide tube, and inner baffles. The shell contains N sets of parallel-arranged cluster plates, where 50 ≥ N ≥ 1. Each set of cluster plates has a guide tube covering its middle section. There are three inner baffles, all arranged perpendicular to the cluster plates, dividing the cluster plates into two sections and the shell into two shell sides. The cluster plate mainly consists of a fixed-end tube sheet, a free-end tube sheet, binding straps, multiple tube-1 plates, one tube-2 plate, and an expansion joint. Tube-1 and tube-2 plates are arranged parallel to each other and have the same length. Tube-1 and tube-2 plates are stacked and combined into one unit by multiple binding straps. One end of tube-1 and tube-2 plate is connected to the fixed-end tube sheet, and the other end is connected to... The tube sheet has a free end, with an expansion joint connected to the other end. Tube sheet one is formed by an inner finned plate and an outer finned plate, sealed together. Tube sheet two is formed by an inner finned plate and an outer folded plate, sealed together. The three inner partitions are: a fixed-end inner partition, a middle inner partition, and a free-end inner partition. The fixed-end inner partition is sealed to the fixed-end tube sheet, the middle inner partition is sealed to the guide tube, and the free-end inner partition is sealed to the expansion joint. Each inner partition has N openings corresponding to N sets of bundled plates. The shell has four interfaces: material flow ① inlet, material flow ① outlet, material flow ② inlet, and material flow ② outlet. When material flow ② flows through the tube side, material flow ① flows through the shell side; when material flow ② flows through the shell side, material flow ① flows through the tube side.

[0020] The further technical feature of the bundled tube air preheater of the present invention is that: the plate tube is M in number, where 200≥M≥10.

[0021] The further technical feature of the bundled tube air preheater of the present invention is that the thickness of the inner fin plate and the outer fin plate ranges from 0.8mm to 2mm.

[0022] The present invention discloses a bundled tube air preheater, further characterized in that: the inner finned plate is composed of an inner folded edge plate, an inner support column, and inner fins. The upper and lower sides of the inner folded edge plate have inner folded edges folded towards the same side as the inner support column. The inner support column and the inner fins are arranged on the same side of the inner folded edge plate, with the inner fins arranged in the middle of the inner folded edge plate and the inner support column arranged at both ends of the inner folded edge plate. The outer finned plate is composed of an outer folded edge plate, an outer support column, and outer fins. The upper and lower sides of the outer folded edge plate have outer folded edges folded towards the opposite side of the outer support column. The outer support column and the outer fins are arranged on the same side of the outer folded edge plate, with the outer fins arranged in the middle of the outer folded edge plate and the outer support column arranged at both ends of the outer folded edge plate. The inner and outer finned plates are made of metal or non-metal.

[0023] The further technical feature of the bundled tube air preheater of the present invention is that the bundled plate is installed vertically, horizontally, or inclined, and the angle of the inclined installation is between 0 and 90°.

[0024] The bundled tube air preheater of the present invention is further characterized in that: the expansion joint includes a U-shaped corrugated section, an upper flange, and a lower flange; the expansion joint is sealed to the free end tube sheet via the upper flange, and the expansion joint is sealed to the free end inner partition via the lower flange. The expansion joint can be a metal expansion joint or a non-metal expansion joint.

[0025] The advantages of this invention compared to the prior art are as follows:

[0026] 1) The air preheater of the present invention has a cluster plate composed of multiple stacked tubes, which has a compact structure. Even if fluoroplastic-graphite or glass plates with poor thermal conductivity are used, the heat transferred can be comparable to that of metal heat exchangers.

[0027] 2) The air preheater of the present invention uses a guide tube to constrain the flue gas and air to exchange heat in a countercurrent manner within the cluster plate. The temperature difference at the hot end can reach the heat exchange limit, which is 10-20% higher than the heat exchange efficiency of the cross-flow plate air preheater of the prior art.

[0028] 3) The air preheater of the bundled plate of the present invention is tightly sealed and leak-free. The inner baffle at the fixed end is connected to the fixed end tube sheet of the bundled plate by bolts, the inner baffle at the middle end is welded to the guide tube, and the inner baffle at the free end is connected to the expansion joint by bolts, so that the incoming and outgoing air and flue gas cannot be cross-connected.

[0029] 4) In the air preheater of the present invention, the gap between the upper and lower sections of the bundled plate tubes that are not covered by the guide tube serves as the inlet and outlet channel for the airflow outside the plate tubes to enter and exit the guide tube. The structure is compact and achieves two goals at once.

[0030] 5) The bundled plate air preheater of the present invention can be installed vertically, horizontally, or at an angle between 0 and 90°, making installation and arrangement convenient.

[0031] 6) The bundled plate air preheater of the present invention has air flowing inside the plate tube and flue gas flowing outside the plate tube, and can be used as a conventional plate air preheater; it can also have flue gas flowing inside the plate tube and air flowing outside the plate tube, and can be used as a flue tube air preheater, which can be flexibly selected.

[0032] 7) The bundled plate air preheater of the present invention has N groups (50≥N≥1) of bundled plates arranged in parallel in the same shell, which can be easily scaled up.

[0033] 8) In the air preheater of the present invention, one end of the tube sheet of the bundled plate is a fixed end and the other end of the tube sheet is a free end. The free end is equipped with an expansion joint, and the bundled plate can freely expand and contract with thermal expansion and contraction.

[0034] 9) The air preheater of the cluster plate of the present invention has free plate material, which can be selected from metal plates and non-metal plates according to different flue gas temperatures.

[0035] 10) The air preheater of the present invention is a modular bundled plate composed of M (200≥M≥10) groups of equal-length plates and tubes stacked together. It has good independence, interchangeability and versatility, and is convenient to manufacture and maintain.

[0036] 11) The air preheater of the bundled plate of the present invention can have its shell side inlet and outlet arranged on the same side, opposite side or adjacent side, and the interface arrangement is flexible.

[0037] 12) The bundled plate air preheater of the present invention has a wide range of applications. It can be used as a medium-temperature air preheater by selecting stainless steel plate or carbon steel plate, and as a low-temperature air preheater by selecting non-metallic plate.

[0038] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but the accompanying drawings and specific embodiments do not limit the scope of the present invention. Attached Figure Description

[0039] Figure 1 A 3D view of the bundled plate air preheater 100 of the present invention;

[0040] Figure 2 This is a 3D cross-sectional view of the bundled plate air preheater 100 of the present invention;

[0041] Figure 3 This is a 3D view of the cluster plate 20 of the present invention;

[0042] Figure 4 This is a 3D view of the plate tube 24 of the present invention;

[0043] Figure 5 This is a 3D view of the second tube 25 of the present invention;

[0044] Figure 6 This is a front view of the inner finned plate 50 of the present invention;

[0045] Figure 7 This is a front view of the outer fin plate 55 of the present invention;

[0046] Figure 8 This is a 3D view of the inner fin plate 50 of the present invention;

[0047] Figure 9 This is a 3D view of the outer fin plate 55 of the present invention;

[0048] Figure 10 for Figure 2 A magnified view of partial view I;

[0049] Figure 11 A 3D schematic diagram showing the countercurrent flow of logistics ① and logistics ② within the bundle tube of the guide tube;

[0050] Figure 12 for Figure 11 3D schematic diagram after removing the inner and outer fins of the plate tube;

[0051] Figure 13 This is a 3D view of the expansion joint 40 of the present invention.

[0052] The attached figures are labeled as follows:

[0053] 100. Bundled plate air preheater;

[0054] ① Logistics; ② Logistics;

[0055] 10. Shell; 11. Shell side; 12. Shell side;

[0056] 13. Logistics ① Import; 14. Logistics ① Export;

[0057] 15. Logistics ② Inbound; 16. Logistics ② Outbound;

[0058] 20. Cluster plate;

[0059] 21. Fixed-end tube sheet; 22. Free-end tube sheet; 23. Cable ties;

[0060] 24. Plate and tube one; 25. Plate and tube two; 26. Bolts and nuts; 27. Strip opening;

[0061] 30. Fixed end inner baffle; 31. Intermediate inner baffle; 32. Free end inner baffle; 33. Flow guide tube;

[0062] 40. Expansion joint;

[0063] 41. U-shaped corrugation; 42. Upper flange; 43. Lower flange;

[0064] 50. Inner fin plate; 51. Inner folded edge plate; 52. Inner support column;

[0065] 53. Inner fins; 54. Inner folded edge;

[0066] 55. Outer fin plate; 56. Outer folded edge plate; 57. Outer support column;

[0067] 58. Outer fins; 59. Outer folded edge. Detailed Implementation

[0068] The invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0069] like Figure 1 As shown, the present invention will be described in detail using a cluster plate air preheater 100 with the cluster plate vertically installed as an example.

[0070] In this embodiment, ① and ② are logistics codes.

[0071] Figure 1 This is a 3D view of the cluster plate air preheater 100 of the present invention. Figure 2 This is a 3D cross-sectional view of a cluster plate air preheater 100 according to the present invention.

[0072] like Figure 1 , Figure 2 As shown, the bundled plate air preheater 100 of the present invention comprises a shell 10, bundled plates 20, a fixed-end inner partition 30, an intermediate inner partition 31, a free-end inner partition 32, and a guide tube 33. Four bundled plates 20 are horizontally arranged within the shell, while the fixed-end inner partition 30, intermediate inner partition 31, and free-end inner partition 32 are vertically arranged. The interior of the shell 10 is divided into two shell sides by the fixed-end inner partition 30, intermediate inner partition 31, and free-end inner partition 32: shell side 11 and shell side 12. The bundled plate 20 is divided into two sections by the intermediate inner partition 31, one section within shell side 11 and the other within shell side 12. The guide tube 33 covers the middle section of the bundled plate 20 and is welded and sealed to the intermediate inner partition 31. The shell 10 has four interfaces: material flow ① inlet 13, material flow ① outlet 14, material flow ② inlet 15, and material flow ② outlet 16.

[0073] Figure 3This is a 3D view of the bundled plate 20 of the present invention. The bundled plate 20 mainly consists of a fixed end tube plate 21, a free end tube plate 22, strapping straps 23, multiple tube plates 24, one tube plate 25, and an expansion joint 40. The tube plates 24 and 25 are arranged in parallel and have the same length. The tube plates 24 and 25 are stacked and combined into one piece by multiple strapping straps 23. One end of the tube plates 24 and 25 is connected to the fixed end tube plate 30, and the other end is connected to the free end tube plate 32. The other end of the free end tube plate 32 is connected to the expansion joint 40. The free end tube plate 22 and the expansion joint 40 are fastened together by bolts and nuts 26. The fixed end tube plate 21 has bolts and nuts 26 that are connected to the inner partition plate 30 of the fixed end, and the expansion joint 40 also has bolts and nuts 26 that are connected to the inner partition plate of the free end. In this embodiment, there are nine tube plates 24 and one tube plate 25. The nine tube plates 24 and one tube plate 25 are stacked and combined into one unit by multiple straps 23. The fixed-end tube plate 21 and the free-end tube plate 22 have strip-shaped openings 27. Through these openings 27, the tube plates 24 and 25 are fixedly and sealed to the fixed-end tube plate 21 and the free-end tube plate 22. The connection method uses existing mature technology and will not be detailed here. The fixed-end tube plate 21 is the fixed end, and the expansion joint 40 connected to the free-end tube plate 22 is the free end. The expansion joint 40 and the free-end tube plate 22 are sealed together by bolts and nuts 26.

[0074] Figure 4 This is a 3D view of the plate tube 24 of the present invention. The plate tube 24 is formed by the interlocking and sealing connection of the inner fin plate 50 and the outer fin plate 55. The specific interlocking and sealing connection method between the inner folded edge 54 of the inner fin plate 50 and the outer folded edge 59 of the outer fin plate 55 can be selected according to the material, such as welding, fusion, or bonding. Welding, fusion, and bonding are existing technologies and will not be described in detail here.

[0075] Figure 5 This is a 3D view of the plate-tube 25 of the present invention. The plate-tube 25 is formed by the interlocking and sealing connection of the inner fin plate 50 and the outer folded edge plate 56. The specific interlocking and sealing connection method between the inner folded edge 54 of the inner fin plate 50 and the outer folded edge 59 of the outer folded edge plate 56 can be selected by welding, fusion, or bonding depending on the material.

[0076] Figure 6 This is a front view of the inner finned plate 50 of the present invention.

[0077] Figure 8 This is a 3D view of the inner fin plate 50 of the present invention.

[0078] like Figure 6 , Figure 8As shown, the inner fin plate 50 consists of an inner folded edge plate 51, an inner support column 52, and inner fins 53. The inner folded edge plate 51 has inner folded edges 54 on its upper and lower sides, folding towards the same plane as the inner support column 52. The inner support column 52 and inner fins 53 are arranged on the same side of the inner folded edge plate 51. The inner fins 53 are located in the middle of the inner folded edge plate 51, and the inner support column 52 is located at both ends of the inner folded edge plate 51. The inner folded edge plate 51, inner support column 52, and inner fins 53 can be made of metallic or non-metallic materials.

[0079] If the inner folded edge plate 51, the inner support column 52, and the inner fin 53 are made of metal, then the inner support column 52 and the inner fin 53 can be welded onto the inner folded edge plate 51.

[0080] If the inner folded edge plate 51, the inner support column 52, and the inner fin 53 are made of fluoroplastic material, then the inner support column 52 and the inner fin 53 can be fused to the inner folded edge plate 51.

[0081] If the inner folded edge plate 51 is made of glass and the inner support column 52 and inner fin 53 are made of non-metallic materials, then the inner support column 52 and inner fin 53 can be bonded to the inner folded edge plate 51.

[0082] Figure 7 This is a front view of the outer fin plate 55 of the present invention.

[0083] Figure 9 This is a 3D view of the outer fin plate 55 of the present invention.

[0084] like Figure 7 , Figure 9 As shown, the outer fin plate 55 consists of an outer folded edge plate 56, an outer support column 57, and outer fins 58. The outer folded edge plate 56 has outer folded edges 59 on its upper and lower sides that fold towards the opposite side of the outer support column 57. The outer support column 57 and outer fins 58 are arranged on the same side of the outer folded edge plate 56. The outer fins 58 are located in the middle of the outer folded edge plate 56, and the outer support column 57 is located at both ends of the outer folded edge plate 56. The outer folded edge plate 56, outer support column 57, and outer fins 58 can be made of metallic or non-metallic materials.

[0085] If the outer folded edge plate 56, the outer support column 57, and the outer fin 58 are made of metal, then the outer support column 57 and the outer fin 58 can be welded onto the outer folded edge plate 56.

[0086] If the outer folded edge plate 56, the outer support column 57, and the outer fin 58 are made of fluoroplastic material, then the outer support column 57 and the outer fin 58 can be fused onto the outer folded edge plate 56.

[0087] If the outer folded edge plate 56 is made of glass and the outer support column 57 and outer fin 58 are made of non-metallic materials, then the outer support column 57 and outer fin 58 can be bonded to the outer folded edge plate 56.

[0088] like Figure 2 and Figure 3 As shown, the fixed-end tube sheet 22 of the bundled plate 20 of the present invention is mounted on the fixed-end inner partition 30. The fixed-end inner partition 30, the intermediate inner partition 31, and the free-end inner partition 32 share the entire weight of the bundled plate 20. The free-end tube sheet 22 and the fixed-end inner partition 30 are positioned and sealed together by bolts and nuts 26. The expansion joint 40 is sealed together with the free-end tube sheet 22 by bolts and nuts 26. The lower flange 43 of the expansion joint 40 is mounted on the free-end inner partition 32 and sealed together by bolts and nuts 26. The middle section of the bundled plate 20 can freely expand and contract due to thermal changes within the guide tube 33. The guide tube 33 is welded and sealed together with the intermediate inner partition 31. The connection between the fixed end inner partition 30, the intermediate inner partition 31, the free end inner partition 32 and the bundle plate 20 ensures the complete sealing of the interior of the bundle plate air preheater 100 of the present invention, preventing the flow of materials ① and ② from being connected. At the same time, it solves the problems of support and thermal expansion and contraction of the bundle plate 20.

[0089] Figure 10 for Figure 2 The enlarged view of partial view I in the middle provides a 3D view of the specific situation of logistics ① and logistics ② entering and exiting the bundle plate 20.

[0090] like Figure 10 As shown, the material flow ① enters the tube 1 24 and tube 2 25 through the strip opening 27 of the fixed end tube plate 21 of the bundle plate 20, flows horizontally, exits the tube 1 24 and tube 2 25 through the strip opening 27 of the free end tube plate 22, and then flows out through the expansion joint 40.

[0091] like Figure 10 As shown, within the shell-side 12 space enclosed by the shell 10, the intermediate inner partition 31, and the free-end inner partition 32, the material flow ② enters the gap between the tubes of the lower section of the bundled plate 20 that is not covered by the guide tube 33, and then enters the guide tube 33. Under the constraint of the guide tube 33, it flows horizontally along the gap between the tubes of tube 1 24 and tube 2 25, and exchanges heat with the material flow ① in the countercurrent flow in tube 1 24 and tube 2 25. Then it exits the guide tube 33 and flows out from the gap between the tubes of the upper section of the bundled plate 20 that is not covered by the guide tube 33, and enters the shell-side 11 space enclosed by the shell 10 and the intermediate inner partition 31 of the fixed-end inner partition 30.

[0092] Figure 11 This is a 3D schematic diagram showing the countercurrent flow of logistics ① and logistics ② within the bundle tube of the guide tube.

[0093] Figure 12 for Figure 11 A 3D diagram showing the plate and tube after removing the inner and outer fins; the plate and tube appear clearer.

[0094] like Figure 11, Figure 12 As shown, material flow ① (white arrow) flows horizontally inside the tubes of tube 1 24 and tube 2 25, and material flow ② (black arrow) flows horizontally along the gap between tubes of tube 1 24 and tube 2 25. Material flow ① and material flow ② flow in opposite directions.

[0095] like Figure 2 As shown, in this embodiment, material ① enters the bundled plate air preheater 100 through material ① inlet 13. Under the obstruction of the fixed end inner partition 30, it flows through the fixed end tube plate 22 of the bundled plate 20 into the tubes of tube 1 24 and tube 2 25. After exchanging heat with material ② in the countercurrent flow, it exits from the expansion joint 40 end of the bundled plate 20 and leaves the bundled plate air preheater 100 through material ① outlet 14.

[0096] like Figure 2 As shown, in this embodiment, material ② enters the shell side 12 of the bundled plate air preheater 100 through material ② inlet 15. In the space of shell side 12, material ② enters the guide tube 33 through the gap between the plate tubes of the lower section of the bundled plate 20 that is not covered by the guide tube 33. Under the constraint of the guide tube 33, material ② flows along the gap between the plate tubes of plate tube 1 24 and plate tube 2 25. After exchanging heat with material ① in the opposite direction, it exits the guide tube 33 through the gap between the plate tubes of the upper section of the bundled plate 20 that is not covered by the guide tube 33 and enters the space of shell side 11. Then it leaves the bundled plate air preheater 100 through material ② outlet 16 that is connected to the space of shell side 11.

[0097] Figure 13 This is a 3D view of the expansion joint 40 of the present invention.

[0098] The expansion joint 40 consists of a U-shaped corrugated section 41, an upper flange 42, and a lower flange 43. In this embodiment, the U-shaped corrugated section 41 is a single corrugation. The U-shaped corrugated section 41 can be made of metal or non-metallic fluoroplastic, depending on the flue gas temperature of the application scenario. Example

[0099] The present invention will be further described in detail below with reference to examples.

[0100] Example 1

[0101] Example 1 uses a cluster plate air preheater 100 provided by the present invention in a low temperature flue gas environment of 150℃.

[0102] In this embodiment, logistics ① is flue gas, and logistics ② is air.

[0103] In this embodiment, the temperature of the flue gas stream ① entering the bundled plate air preheater 100 is 20°C.

[0104] In this embodiment, the temperature of the air flow ② entering the bundled plate air preheater 100 is 150°C.

[0105] In this embodiment, since the temperature of flue gas stream ① entering the bundled plate air preheater 100 is 150°C and the temperature of air stream ② entering the bundled plate air preheater 100 is 20°C, water condenses on the flue gas side during the heat exchange process, resulting in flue gas dew point corrosion. Therefore, plate tube 1 24 and plate tube 2 25 are made of polytetrafluoroethylene (PTFE), expansion joint 40 is a PTFE expansion joint, and the bolts and nuts 26 at the lower end of expansion joint 40 are PTFE bolts and nuts. The inner partition 32 and the surface of stream ① outlet 14 that contacts flue gas stream ① are lined with PTFE.

[0106] like Figure 2 As shown, in this embodiment, flue gas stream ① at 150°C enters the bundled plate air preheater 100 through stream ① inlet 13 and exits through stream ① outlet 14. The temperature of flue gas stream ① at the time of exit is approximately 85°C.

[0107] like Figure 2 As shown, in this embodiment, 20°C air stream ② enters the bundled plate air preheater 100 through stream ② inlet 15 and exits through stream ② outlet 16. The temperature of air stream ② at the time of exit is approximately 100°C.

[0108] In this embodiment, since the first plate tube 24 and the second plate tube 25, the expansion joint 40, and the bolts and nuts 26 at the lower end of the expansion joint 40 are all made of polytetrafluoroethylene, and the inner partition 32 at the free end and the surface of the outlet 14 of the flow ① that contacts the flue gas flow ① are lined with polytetrafluoroethylene, they all have the property of resisting flue gas dew point corrosion. Therefore, the bundled plate air preheater 100 of Embodiment 1 can operate safely under the flue gas dew point.

[0109] Example 2

[0110] Example 2 uses a cluster plate air preheater 100 provided by the present invention in a medium-temperature flue gas environment at 300℃.

[0111] In this embodiment, logistics ① is air, and logistics ② is flue gas.

[0112] In this embodiment, the temperature of the flue gas stream ② entering the bundled plate air preheater 100 is 300°C.

[0113] In this embodiment, the temperature of the air flow ① entering the bundled plate air preheater 100 is 100°C.

[0114] In this embodiment, since the temperature of flue gas stream ② entering the bundled plate air preheater 100 is 300°C and the temperature of air stream ① entering the bundled plate air preheater 100 is 100°C, there is no flue gas dew point corrosion problem. Therefore, plate tube 1 24 and plate tube 2 25 are selected as carbon steel pipes (or stainless steel pipes), expansion joint 40 is selected as a stainless steel expansion joint, and the bolt and nut 26 at the lower end of expansion joint 40 is selected as carbon steel.

[0115] like Figure 2 As shown, in this embodiment, flue gas stream ② at 300°C enters the bundled plate air preheater 100 through stream ② inlet 15 and exits through stream ② outlet 16. The temperature of flue gas stream ② at the time of exit is approximately 150°C.

[0116] like Figure 2 Figure 2 As shown, in this embodiment, 100°C air stream ① enters the bundled plate air preheater 100 through stream ① inlet 13 and exits through stream ① outlet 14. The temperature of air stream ① at the time of exit is approximately 280°C.

[0117] In this embodiment, since there is no flue gas dew point corrosion problem, carbon steel pipes (or stainless steel pipes) are selected for plate tube 24 and plate tube 25, and stainless steel expansion joint 40 is selected for expansion joint 40. Therefore, the cluster plate air preheater 100 of Embodiment 2 can operate safely in a medium-temperature flue gas environment of 300°C.

Claims

1. A bundled plate air preheater characterized by: The bundle plate air preheater mainly comprises a shell, bundle plates, a flow guide cylinder and inner baffles, the shell has N groups of parallel arranged bundle plates, wherein 50>=N>=1, each group of bundle plates is coated with a flow guide cylinder at the middle section, the inner baffles are three and arranged perpendicularly to the bundle plates, the three inner baffles divide the bundle plates into two sections and divide the shell into two shell sections; the bundle plate mainly comprises a fixed end tube plate, a free end tube plate, a binding belt, a plurality of plate tubes one, one plate tube two and an expansion joint, the plate tube one and the plate tube two are arranged in parallel and have the same length, the plate tube one and the plate tube two are combined into one by a plurality of binding belts, one end of the plate tube one and the plate tube two is connected with the fixed end tube plate, the other end is connected with the free end tube plate, the other end of the free end tube plate is connected with the expansion joint, the plate tube one is connected by the inner fin plate and the outer fin plate, the plate tube two is connected by the inner fin plate and the outer folded edge plate, the three inner baffles are a fixed end inner baffle, an intermediate inner baffle and a free end inner baffle, wherein the fixed end inner baffle is connected with the fixed end tube plate, the intermediate inner baffle is connected with the flow guide cylinder, the free end inner baffle is connected with the expansion joint, each inner baffle is provided with N openings corresponding to the N groups of bundle plates, the shell has four interfaces, which are a material flow 1 inlet, a material flow 1 outlet, a material flow 2 inlet and a material flow 2 outlet, when the material flow 2 flows through the tube section, the material flow 1 flows through the shell section, when the material flow 2 flows through the shell section, the material flow 1 flows through the tube section, in the space surrounded by the shell, the intermediate inner baffle and the free end inner baffle, the material flow 2 enters the gap between the plate tubes of the lower section of the bundle plate which is not coated with the flow guide cylinder, then enters the flow guide cylinder, under the constraint of the flow guide cylinder, the material flow 2 flows horizontally along the gap between the plate tubes one and the plate tubes two, and then exchanges heat with the material flow 1 in the plate tube one and the plate tube two, and then flows out of the flow guide cylinder, and then flows out of the gap between the plate tubes of the upper section of the bundle plate which is not coated with the flow guide cylinder, and then enters the space surrounded by the shell, the fixed end inner baffle and the intermediate inner baffle; The inner fin plate comprises an inner folded edge plate, an inner support column and an inner fin, the inner folded edge plate has inner folded edges on the upper and lower sides which are folded towards the same surface of the inner support column, the inner support column and the inner fin are arranged on the same side of the inner folded edge plate, the inner fin is arranged in the middle of the inner folded edge plate, and the inner support column is arranged at both ends of the inner folded edge plate; The thickness of the inner fin plate and the outer fin plate ranges from 0.8mm to 2mm; The outer fin plate comprises an outer folded edge plate, an outer support column and an outer fin, the outer folded edge plate has outer folded edges on the upper and lower sides which are folded towards the opposite surface of the outer support column, the outer support column and the outer fin are arranged on the same side of the outer folded edge plate, the outer fin is arranged in the middle of the outer folded edge plate, and the outer support column is arranged at both ends of the outer folded edge plate; The plate tube one and the plate tube two are made of polytetrafluoroethylene material.

2. A bundled plate air preheater according to claim 1, characterized in that: The plate tube one is M, 200>=M>=10.

3. A bundled plate air preheater according to claim 1, characterized in that: The length of the flow guide cylinder is 1 / 10 to 2 / 3 of the length of the bundle plate.

4. A bundled plate air preheater according to claim 1, characterized in that: The bundle plate is installed vertically, horizontally or obliquely, and the angle of the oblique installation is between 0 and 90 degrees.

5. A bundled plate air preheater according to claim 1, characterized in that: The expansion joint comprises a U-shaped wave node, an upper end flange and a lower end flange, the expansion joint is connected with the free end tube plate through the upper end flange, and the expansion joint is connected with the free end inner baffle through the lower end flange.

6. A bundled plate air preheater according to claim 5, characterized in that: The expansion joint is a metal expansion joint or a non-metal expansion joint. The expansion joint is a metal expansion joint or a non-metal expansion joint.

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