Air preheater with fluorine plastic films wrapped outside oval pipes

Abstract

The utility model relates to the technical field of air pre-heaters, and discloses an air pre-heater with elliptical tubes wrapped by fluoroplastic films, which comprises an air inlet piece, an elliptical tube bundle, a flow guide plate and a modularized support frame consisting of support side plates and a top plate, the air inlet piece is arranged at the opening end of the side wall of the modularized support frame, and the flow guide plate is arranged at the opening end of the side wall of the modularized support frame. The air inlet part is connected with the side wall of the modular supporting frame in a matched mode through adaptive bolts, a set of oval tube bundles distributed in an equidistant array mode are arranged in the modular supporting frame, a set of flow guide plates distributed in an equidistant mode are arranged between the oval tube bundles, and the flow guide plates are in a horizontal state. According to the air preheater, the elliptical tube bundle design and the wave-shaped flow guide plates are arranged in the air preheater, so that the service life of the whole structure can be greatly prolonged, and the working quality of the whole structure can be greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of air preheater technology, specifically to an air preheater with an elliptical tube wrapped with a fluoroplastic film. Background Technology

[0002] In the fields of energy utilization and industrial production, boiler equipment, as an important energy conversion device, is widely used in many industries such as power, chemical, and heating. As a key component of the boiler system, the performance of the air preheater directly affects the boiler's thermal efficiency and overall operating effect.

[0003] However, traditional air preheaters mostly adopt a circular tube structure, with carbon steel or stainless steel as the main materials. This has the following problems: tube corrosion, where sulfur and acidic components in the flue gas easily lead to tube wall corrosion and shorten service life; internal ash accumulation and blockage, where ash easily adheres to the surface of the circular tubes, reducing heat transfer efficiency and increasing maintenance costs; high flue gas flow resistance, where the circular tube arrangement results in low airflow turbulence and a thick heat transfer boundary layer, limiting efficiency; and although existing technologies use anti-corrosion coatings, these coatings are prone to peeling and have insufficient temperature resistance. Therefore, we propose an air preheater with an elliptical tube wrapped with a fluoroplastic film. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides an air preheater with an elliptical tube wrapped with a fluoroplastic film, thus solving the aforementioned problems.

[0006] (II) Technical Solution

[0007] To achieve the above-mentioned objectives, this utility model provides the following technical solution: an air preheater with an elliptical tube wrapped with a fluoroplastic film, comprising an air inlet, an elliptical tube bundle, and a guide plate, as well as a modular support frame composed of a supporting side plate and a top plate. The air inlet is provided at the open end of the side wall of the modular support frame, and the air inlet is connected to the side wall of the modular support frame by a matching bolt. Inside the modular support frame, there is a set of elliptical tube bundles distributed in an equidistant array, and a set of guide plates distributed in an equidistant array are provided between the elliptical tube bundles. The guide plates are in a horizontal state and are slidably connected to the inner wall of the modular support frame.

[0008] Preferably, the modular support frame is in the shape of a horizontally placed hollow column, consisting of two sets of support side plates and a top plate that are symmetrically distributed along an axis, and adjacent support side plates and top plates are perpendicularly distributed. The corresponding connecting end sidewalls of the support side plates and top plates are connected by matching bolts.

[0009] Preferably, the sidewall of the modular support frame is a support side plate, and the sidewall of the support side plate has a set of mating openings distributed in an equidistant array, and a ring of connecting holes is provided around the mating openings. A sliding groove is provided between the corresponding rows of the mating openings on the sidewall of the support side plate.

[0010] Preferably, the elliptical tube bundle body is a tube bundle body, the outer side of the tube bundle body is provided with a pretreatment layer, and the outer side of the pretreatment layer is provided with a fluoroplastic film layer. The tube bundle body corresponds to the mating port, and the two shaft ends of the tube bundle body are provided with flanges. A ring of connecting holes one is opened on the flange end face. Connecting hole one is connected to connecting hole two through an adapter bolt.

[0011] Preferably, the fluoroplastic film layer is any one of polytetrafluoroethylene or fluorinated ethylene propylene copolymer material.

[0012] Preferably, the guide plate has two opposite sidewalls with axially symmetrically distributed sliding blocks, which are connected to the sliding groove. A curved plate is provided between the two sliding blocks. The curved plate is wavy and has a set of vent holes on the protruding part. There is a concave area between adjacent vent holes.

[0013] (III) Beneficial Effects

[0014] Compared with the prior art, this utility model provides an air preheater with an elliptical tube wrapped with a fluoroplastic film, which has the following advantages:

[0015] 1. This air preheater with an elliptical tube covered by a fluoroplastic film significantly improves boiler thermal efficiency. The unique structure of the elliptical tube increases the heat transfer area and reduces airflow resistance. Furthermore, the guide plate guides the flue gas to flow evenly and enhances turbulence, promoting heat transfer. For example, in boiler applications in chemical production, compared to traditional air preheaters, it can transfer more heat to the air, raising the temperature of the air entering the boiler combustion system, allowing for more complete fuel combustion, thereby improving the overall thermal efficiency of the boiler, reducing energy consumption, and saving enterprises a significant amount of energy costs.

[0016] 2. The air preheater with an outer fluoroplastic film covering the elliptical tube significantly extends the service life of the equipment. The fluoroplastic film layer has chemical inertness and extremely low surface energy, which can effectively resist the corrosion of sulfur-containing flue gas and reduce ash accumulation. This extends the service life of the elliptical tube bundle in harsh environments to more than twice that of traditional air preheaters. In the long-term operation of boilers in the power industry, it reduces the frequency of equipment replacement, lowers equipment maintenance costs, reduces downtime caused by equipment replacement, ensures production continuity, and improves the economic benefits and production stability of enterprises. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the air preheater structure of the elliptical tube wrapped with a fluoroplastic film according to this utility model.

[0018] Figure 2 This is a cross-sectional schematic diagram of the air preheater with an elliptical tube wrapped with a fluoroplastic film according to this utility model;

[0019] Figure 3 This is a schematic diagram of the supporting side plate of this utility model;

[0020] Figure 4 This is a schematic cross-sectional view of the elliptical tube bundle of this utility model;

[0021] Figure 5 This is a schematic diagram of the guide plate of this utility model.

[0022] In the diagram: 1. Support side plate; 2. Air inlet; 3. Top plate; 4. Elliptical tube bundle; 5. Guide plate; 6. Mating port; 7. Slide groove; 8. Flange; 9. Tube bundle body; 10. Pretreatment layer; 11. Fluoroplastic film layer; 12. Connection hole one; 13. Mating slider; 14. Bending plate; 15. Vent hole; 16. Recessed area; 17. Connection hole two. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] Please see Figures 1-5 An air preheater with an elliptical tube wrapped with a fluoroplastic film includes an air inlet 2, an elliptical tube bundle 4, and a guide plate 5, as well as a modular support frame composed of a support side plate 1 and a top plate 3. The air inlet 2 is provided at the open end of the side wall of the modular support frame. The air inlet 2 is connected to the side wall of the modular support frame by a matching bolt. Inside the modular support frame, there is a set of elliptical tube bundles 4 distributed in an equidistant array. A set of guide plates 5 are distributed in an equidistant array between the elliptical tube bundles 4. The guide plates 5 are in a horizontal state and are slidably connected to the inner wall of the modular support frame.

[0025] Furthermore, the modular support frame is in the shape of a horizontal hollow column, consisting of two sets of support side plates 1 and top plate 3 that are symmetrically distributed along the axis. Adjacent support side plates 1 and top plate 3 are vertically distributed. The corresponding connecting end sidewalls of support side plates 1 and top plate 3 are connected by matching bolts. The modular support frame facilitates the transportation of materials, subsequent assembly, disassembly and maintenance, and improves the overall structural practicality.

[0026] Furthermore, the modular support frame sidewall is a support side plate 1. The support side plate 1 has a set of mating ports 6 arranged in an equidistant array on its sidewall, and a ring of connecting holes 17 are arranged around the mating ports 6. The support side plate 1 has a sliding groove 7 between the corresponding rows of mating ports 6 on its sidewall. The sliding groove 7 facilitates the installation and disassembly of the guide plate 5, and also facilitates the cleaning of dust and impurities deposited on the guide plate 5.

[0027] Furthermore, the main body of the elliptical tube bundle 4 is the tube bundle body 9. A pretreatment layer 10 is provided on the outside of the tube bundle body 9, and a fluoroplastic film layer 11 is provided on the outside of the pretreatment layer 10. The tube bundle body 9 corresponds to the mating port 6, and flanges 8 are provided at both ends of the tube bundle body 9. A ring of connecting holes 12 is opened on the end face of the flange 8. The connecting holes 12 are connected to the connecting holes 17 by matching bolts. The tube bundle body 9 adopts an elliptical tube with a major axis to minor axis ratio of 2:1 to 3:1. Its tube material is aluminum alloy or 316L stainless steel with a smooth inner wall. Compared with traditional round tubes, the heat transfer area of ​​the elliptical tube increases by 15% to 20% under the same cross-sectional perimeter. When the airflow flows along the major axis, the boundary layer is thinner, and the resistance is reduced by 10% to 15%. The pretreatment layer 10 is to improve the roughness of the tube wall through pretreatment (sandblasting + chemical etching) so that the bonding strength of the fluoroplastic film layer 11 reaches 8 to 12 MPa, avoiding peeling failure and improving service life.

[0028] Furthermore, the fluoroplastic film layer 11 is any one of polytetrafluoroethylene or fluorinated ethylene propylene copolymer material, and the thickness of the fluoroplastic film layer 11 is 0.2 to 0.5 mm. It is bonded to the outer wall of the tube bundle body 9 by hot pressing or plasma spraying process. The temperature resistance range of the fluoroplastic film layer 11 is -200℃ to 260℃, chemically inert, and has extremely low surface energy (contact angle > 110°), which significantly reduces the adhesion of ash. The fluoroplastic film layer 11 extends the service life of the elliptical tube bundle 4 in sulfur-containing flue gas environment to more than 3 times that of traditional air preheaters.

[0029] Furthermore, the guide plate 5 has two opposite sidewalls with symmetrically distributed sliding blocks 13. The sliding blocks 13 correspond to the sliding connection inside the groove 7. A curved plate 14 is provided between the two sliding blocks 13. The curved plate 14 is wavy and has a set of ventilation holes 15 on its protruding part. There is a recessed area 16 between adjacent ventilation holes 15. The guide plate 5 can guide the cross flow of flue gas and air to enhance turbulence. The ventilation holes 15 can make the flue gas evenly distributed inside the modular support frame to improve the heat transfer quality. The recessed area 16 can bear dust and particulate matter, reduce the dust accumulation on the outside of the elliptical tube bundle 4, and extend the cleaning cycle from 7 days to more than 30 days.

[0030] Structural Description:

[0031] Support side plate 1: The support side plate 1 is the side wall of the modular support frame, with mating openings 6 and sliding grooves 7. It is connected to the top plate 3 by adapter bolts, providing support for the elliptical tube bundle 4 and facilitating the installation of the guide plate 5.

[0032] Inlet component 2: Inlet component 2 is installed at the opening end of the side wall of the modular support frame and is connected by adapter bolts. It is the channel for flue gas to enter the preheater and ensures that the flue gas enters the interior smoothly.

[0033] Top plate 3: Top plate 3 and supporting side plate 1 form a modular support frame, which are distributed vertically adjacent to each other and connected by adapter bolts. Together with supporting side plate 1, they support and protect the internal components.

[0034] Elliptical tube bundle 4: The elliptical tube bundle 4 is located within the modular support frame. Its main body is the tube bundle body 9, and it is covered by a pretreatment layer 10 and a fluoroplastic film layer 11. It is a key component for heat exchange and improves heat transfer efficiency.

[0035] Baffle 5: The baffle 5 is located between the elliptical tube bundles 4 and is slidably connected to the slide groove 7 by the sliding block 13, which guides the cross flow of flue gas and air, enhances turbulence, and improves heat transfer quality.

[0036] Fitting port 6: The fitting ports 6 are distributed in an equidistant array on the side wall of the support side plate 1, and are surrounded by connecting holes 17. They fit with the flange 8 of the elliptical tube bundle 4 to realize the installation and fixation of the tube bundle.

[0037] Slide groove 7: Slide groove 7 is formed on the side wall of the support side plate 1 to facilitate the installation, disassembly and cleaning of the guide plate 5, and to provide a track for the sliding of the guide plate 5;

[0038] Flange 8: Flange 8 is located at both ends of the tube bundle body 9 and has a first connection hole 12. It is connected to the second connection hole 17 by an adapter bolt to fix the elliptical tube bundle 4 and ensure a stable connection.

[0039] Tube bundle body 9: Tube bundle body 9 is the main body of elliptical tube bundle 4. It adopts elliptical tubes of a specific ratio and is made of aluminum alloy or 316L stainless steel. It is the carrier of heat transfer.

[0040] Pretreatment layer 10: The pretreatment layer 10 is located on the outside of the tube bundle body 9. It is treated by sandblasting and chemical etching to improve the roughness of the tube wall and enhance the bonding strength of the fluoroplastic film layer 11.

[0041] Fluoroplastic membrane layer 11: Fluoroplastic membrane layer 11 covers the outside of pretreatment layer 10, is made of a specific material, is temperature resistant and chemically inert, reduces dust accumulation and protects the tube bundle body 9;

[0042] Connection hole 12: Connection hole 12 is distributed in a ring on the end face of flange 8. It is connected to the elliptical tube bundle 4 and the support side plate 1 by matching the adapter bolt with connection hole 2 17.

[0043] Matching slider 13: Matching slider 13 is symmetrically distributed on the side wall of the guide plate 5 and slides in conjunction with the slide groove 7, so that the guide plate 5 can slide within the frame, which is convenient for adjustment and cleaning;

[0044] Bending plate 14: The bending plate 14 is located between the two mating sliders 13 of the guide plate 5 and is wavy. The vent holes 15 and the recesses 16 on it help to distribute the flue gas and carry dust.

[0045] Vent hole 15: Vent hole 15 is provided on the protrusion of the curved plate 14, which can make the flue gas evenly distributed in the modular support frame and improve the heat transfer uniformity.

[0046] Recess 16: Recess 16 is located between adjacent vents 15 and is used to hold dust and particulate matter, reducing dust accumulation on the outside of the elliptical tube bundle 4.

[0047] Connection Hole 2 17: Connection Hole 2 17 is distributed in a ring around the fitting port 6 on the support side plate 1, and mates with Connection Hole 1 12, for installing and fixing the elliptical tube bundle 4.

[0048] Working Principle: After correctly installing the air preheater with the elliptical tube covered in fluoroplastic film according to the diagram, during operation, the modular support frame first provides stable structural support for the entire preheater. The modular support frame, composed of support side plates 1 and a top plate 3, facilitates transportation, assembly, and maintenance. The flue gas generated by the boiler enters the modular support frame through the inlet 2. The inlet 2 is tightly connected to the frame sidewall by matching bolts to ensure no flue gas leakage. The flue gas entering the frame flows under the guidance of the guide plate 5. The guide plate 5 slides along the groove 7 on the support side plate 1 via a matching slider 13. The connection, installation, and disassembly are convenient, facilitating dust cleaning. The curved plate 14 on the guide plate 5 is wavy, and its protruding vent holes 15 allow the flue gas to be evenly distributed within the frame, enhancing the turbulence of the flue gas and improving heat transfer efficiency. Simultaneously, the recessed area 16 can hold dust and particulate matter, reducing dust accumulation on the outside of the elliptical tube bundle 4 and extending the cleaning cycle. The elliptical tube bundle 4 is the core component of the preheater. Its main tube bundle body 9 uses elliptical tubes with a specific ratio of major to minor axis. Compared to traditional round tubes, with the same cross-sectional perimeter, the heat transfer area is increased, and the airflow resistance is reduced. The outer pretreatment layer 10 improves the roughness of the tube wall through sandblasting and chemical etching, ensuring that the bonding strength of the fluoroplastic film layer 11 reaches 8-12 MPa. This prevents the fluoroplastic film layer 11 from easily peeling off and failing. The fluoroplastic film layer 11 is made of polytetrafluoroethylene or fluorinated ethylene propylene copolymer, with a thickness of 0.2-0.5 mm. It is bonded to the tube bundle body 9 through hot pressing or plasma spraying. It is chemically inert, has extremely low surface energy, and a contact angle greater than 110°, which can significantly reduce ash adhesion. It also has a temperature resistance range of -200℃ to 260℃, effectively protecting the tube bundle in sulfur-containing flue gas environments. The main body 9 extends the lifespan of the elliptical tube bundle 4 to more than three times that of a traditional air preheater. During flue gas flow, the elliptical tube bundle 4 is in full contact with the flue gas. Due to the special structure of the elliptical tube and the characteristics of the fluoroplastic film layer 11, the heat in the flue gas is efficiently transferred to the elliptical tube bundle 4, thereby heating the air inside the tube. The flanges 8 at both ends of the tube bundle body 9 are connected to the support side plate 1 through the first connection hole 12 and the second connection hole 17 with matching bolts, ensuring the stable installation of the elliptical tube bundle 4. Finally, the preheated air is delivered to the boiler combustion system, improving the boiler's thermal efficiency and achieving efficient energy conversion.

[0049] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An air preheater of the type having an outer covering of fluoroplastic film on an elliptical tube, characterized in that, The utility model relates to a modular support frame of air preheater, including air inlet part (2), elliptical tube bundle (4) and deflector (5) and the modular support frame of support side plate (1) and top plate (3) composition, modular support frame side wall opening end is equipped with air inlet part (2), air inlet part (2) is connected with modular support frame side wall through adaptive bolt, and modular support frame inside is equipped with a set of equidistance array distribution's elliptical tube bundle (4), be equipped with a set of equidistance distribution's deflector (5) between elliptical tube bundle (4), deflector (5) is horizontal state, and deflector (5) corresponding with modular support frame inner wall slidingly connected.

2. An air preheater according to claim 1, wherein: The utility model relates to a modular support frame of air preheater, including air inlet part (2), elliptical tube bundle (4) and deflector (5) and the modular support frame of support side plate (1) and top plate (3) composition, modular support frame side wall opening end is equipped with air inlet part (2), air inlet part (2) is connected with modular support frame side wall through adaptive bolt, and modular support frame inside is equipped with a set of equidistance array distribution's elliptical tube bundle (4), be equipped with a set of equidistance distribution's deflector (5) between elliptical tube bundle (4), deflector (5) is horizontal state, and deflector (5) corresponding with modular support frame inner wall slidingly connected.

3. An air preheater according to claim 2, wherein: The utility model relates to a modular support frame of air preheater, including air inlet part (2), elliptical tube bundle (4) and deflector (5) and the modular support frame of support side plate (1) and top plate (3) composition, modular support frame side wall opening end is equipped with air inlet part (2), air inlet part (2) is connected with modular support frame side wall through adaptive bolt, and modular support frame inside is equipped with a set of equidistance array distribution's elliptical tube bundle (4), be equipped with a set of equidistance distribution's deflector (5) between elliptical tube bundle (4), deflector (5) is horizontal state, and deflector (5) corresponding with modular support frame inner wall slidingly connected.

4. An air preheater according to claim 1, wherein: The utility model relates to a modular support frame of air preheater, including air inlet part (2), elliptical tube bundle (4) and deflector (5) and the modular support frame of support side plate (1) and top plate (3) composition, modular support frame side wall opening end is equipped with air inlet part (2), air inlet part (2) is connected with modular support frame side wall through adaptive bolt, and modular support frame inside is equipped with a set of equidistance array distribution's elliptical tube bundle (4), be equipped with a set of equidistance distribution's deflector (5) between elliptical tube bundle (4), deflector (5) is horizontal state, and deflector (5) corresponding with modular support frame inner wall slidingly connected.

5. An air preheater according to claim 4, wherein: The utility model relates to a modular support frame of air preheater, including air inlet part (2), elliptical tube bundle (4) and deflector (5) and the modular support frame of support side plate (1) and top plate (3) composition, modular support frame side wall opening end is equipped with air inlet part (2), air inlet part (2) is connected with modular support frame side wall through adaptive bolt, and modular support frame inside is equipped with a set of equidistance array distribution's elliptical tube bundle (4), be equipped with a set of equidistance distribution's deflector (5) between elliptical tube bundle (4), deflector (5) is horizontal state, and deflector (5) corresponding with modular support frame inner wall slidingly connected.

6. An air preheater according to claim 1, wherein: The utility model relates to a modular support frame of air preheater, including air inlet part (2), elliptical tube bundle (4) and deflector (5) and the modular support frame of support side plate (1) and top plate (3) composition, modular support frame side wall opening end is equipped with air inlet part (2), air inlet part (2) is connected with modular support frame side wall through adaptive bolt, and modular support frame inside is equipped with a set of equidistance array distribution's elliptical tube bundle (4), be equipped with a set of equidistance distribution's deflector (5) between elliptical tube bundle (4), deflector (5) is horizontal state, and deflector (5) corresponding with modular support frame inner wall slidingly connected.

Images