A plate fin and a heat exchanger having the same

Abstract

A kind of plate fin and the heat exchanger with the plate fin, heat exchanger includes several plate fins, several heat exchange tubes (4) connected with plate fin, same group plate fin is worn on same row heat exchange tube;Plate fin includes heat conduction sheet (1), several heat exchange tube mounting holes (2) arranged on heat conduction sheet, protective sheet (3) wrapped outside heat conduction sheet, the outer surface of heat conduction sheet (1) and protective sheet (3) group is pressed into corrugated shape;It also has first tube plate (5) and second tube plate (6) respectively located in both sides of same group plate fin, with the inlet header (7) connected with first tube plate, with the outlet header (8) connected with second tube plate, sealing layer (9) wrapped outside heat exchange tube, and first tube plate and second tube plate are connected with heat exchange tube.The technical scheme provided by the utility model can avoid that external heat exchange fluid medium causes corrosion and abrasion to heat exchanger.

Description

Technical Field

[0001] This utility model relates to the field of heat exchange equipment technology, and in particular to plate fins. This utility model also relates to a heat exchanger. Background Technology

[0002] The use of flue gas economizers in existing coal-fired power plant boilers can reduce the exhaust gas temperature and improve the boiler thermal efficiency. Currently, there are two main types of flue gas economizers used in power plants: fluoroplastic tubular heat exchangers and tubular heat exchangers (including H-type and finned tubes) represented by ND steel. They have the following shortcomings.

[0003] Technical problems with flue gas economizers represented by ND steel: ND steel has strong resistance to sulfuric acid corrosion, but corrosion in flue gas is very complex. To ensure the safe operation of power plants, heat exchangers are generally protected by increasing the exhaust temperature. Therefore, when using ND steel for deep flue gas cooling, the flue gas temperature cannot be reduced to its extreme. In tubular heat exchangers, at low flue gas velocities, the flue gas does not flow between the fins, resulting in low heat exchange efficiency. When the flue gas velocity is increased, the flue gas escapes from the area of ​​least resistance between the two finned tubes, without effective heat exchange. Simultaneously, at excessively high flue gas velocities, the resistance loss is large. Therefore, the temperature difference in tubular heat exchangers is typically 40-50℃. Taking condensate from the condenser at 40℃ as an example, after passing through the heat exchanger, the exhaust gas temperature is still 80-90℃, failing to fully utilize the waste heat of the flue gas, especially the latent heat of water vapor, resulting in low heat recovery efficiency. Tubular heat exchangers are large in size and weight, complex to hoist, and have a significant impact on the overall system. Tubular heat exchangers suffer from high resistance losses, necessitating modifications to the existing induced draft fan configuration in power plants. Their large size and axial length also make thorough cleaning impossible. Furthermore, the lifespan of tubular heat exchangers is limited by the corrosion resistance of the materials used.

[0004] Technical problems with flue gas economizers made of fluoroplastic tubes: While fluoroplastic tubes have strong corrosion resistance, they are prone to decomposition at temperatures above 300℃. The heat transfer coefficient of fluoroplastic tubes is lower than that of ND steel, resulting in lower heat transfer efficiency. Similar to ND steel tube heat exchangers, they also experience significant resistance losses, affecting the balance of the existing system. Cleaning and maintenance are the most critical shortcomings of fluoroplastic heat exchangers. Although fluoroplastics themselves have non-stick properties, scale deposited between the tubes can form a sludge mass over time, sealing the entire heat exchanger. Due to the small tube spacing and long axial length, maintenance becomes impossible, forcing the entire unit to be scrapped. The service life of fluoroplastic heat exchangers is limited by plastic aging and localized accelerated aging.

[0005] Therefore, developing heat exchanger technologies that can reduce flue gas temperature and are corrosion-resistant has significant economic and social benefits. Utility Model Content

[0006] To overcome the shortcomings of existing technologies, this invention provides a plate-finned heat exchanger that improves heat exchange efficiency and corrosion resistance.

[0007] To solve the above-mentioned technical problems, on the one hand, the plate fin provided by this utility model includes a heat-conducting plate, a plurality of heat exchange tube mounting holes provided on the heat-conducting plate, and a protective plate wrapped around the outside of the heat-conducting plate. After the heat-conducting plate and the protective plate are assembled, their outer surfaces are pressed into a corrugated shape.

[0008] As a further improved technical solution, the plate fins provided by this utility model have flanged mounting holes for the heat exchange tubes.

[0009] To address the aforementioned technical problems, the present invention provides a heat exchanger comprising several plate fins, several heat exchange tubes connected to the plate fins, with the same group of plate fins mounted on the same row of heat exchange tubes; each plate fin includes a heat-conducting plate, several heat exchange tube mounting holes disposed on the heat-conducting plate, and a protective plate covering the outside of the heat-conducting plate; the outer surfaces of the heat-conducting plate and the protective plate are corrugated after assembly; it also includes a first tube sheet and a second tube sheet located on both sides of the same group of plate fins, an inlet header connected to the first tube sheet, an outlet header connected to the second tube sheet, and a sealing layer covering the outside of the heat exchange tubes; both the first tube sheet and the second tube sheet are connected to the heat exchange tubes.

[0010] As a further improved technical solution, the heat exchanger provided by this utility model has a flanged mounting hole for the heat exchange tube.

[0011] The technical solution provided by this utility model is that the protective plate wraps the heat-conducting plate, and the sealing layer also wraps the heat exchange tube and the heat-conducting plate near the heat exchange tube, thereby isolating the heat exchanger from the external heat exchange fluid medium and preventing the external heat exchange fluid medium from corroding and wearing the heat exchanger. It can solve the heat exchange needs in environments such as coal-fired boiler flues. Attached Figure Description

[0012] The accompanying drawings are provided to further illustrate the present invention and form part of this application, but do not constitute an undue limitation of the present invention. In the drawings:

[0013] Figure 1 This is a schematic diagram of the main structure of the plate fin in the embodiment;

[0014] Figure 2 This is a schematic diagram of the left-side structure of the plate fin in the embodiment;

[0015] Figure 3 This is a schematic diagram of the main structure of the heat exchanger in the embodiment. Implementation

[0016] The embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0017] like Figure 1 and Figure 2 The plate fin shown includes a heat-conducting plate 1, several heat exchange tube mounting holes 2 disposed on the heat-conducting plate 1, and a protective plate 3 covering the outside of the heat-conducting plate 1. After assembly, the outer surfaces of the heat-conducting plate 1 and the protective plate 3 are corrugated, and the heat exchange tube mounting holes 2 have flanges. The plate fin adopts a sandwich structure, with the fin consisting of three layers of plates. The outer layer uses two corrosion-resistant and wear-resistant protective plates 3, such as titanium, stainless steel, or other metal or non-metal plates. The inner layer uses a heat-conducting plate 1 with good thermal conductivity, such as steel, silicon carbide, or copper. After assembly, the protective plates 3 on both sides of the heat-conducting plate 1 are fixed by welding, bonding, or other methods, sealing the heat-conducting plate 1 inside the protective plates 3. The protective plates 3 enclose and seal the heat-conducting plate 1, thereby isolating the heat-conducting plate 1 from the external heat exchange fluid medium.

[0018] like Figure 3 The heat exchanger shown includes several plate fins and several heat exchange tubes 4 connected to the plate fins. Plate fins in the same group are threaded onto the same row of heat exchange tubes 4. Each plate fin includes a heat-conducting plate 1, several heat exchange tube mounting holes 2 on the heat-conducting plate 1, and a protective plate 3 covering the outside of the heat-conducting plate 1. The outer surfaces of the heat-conducting plate 1 and the protective plate 3 are corrugated after assembly. It also has a first tube sheet 5 and a second tube sheet 6 located on either side of the same group of plate fins, an inlet header 7 connected to the first tube sheet 5, an outlet header 8 connected to the second tube sheet 6, and a sealing layer 9 covering the outside of the heat exchange tubes 4. Both the first tube sheet 5 and the second tube sheet 6 are connected to the heat exchange tubes 4. The heat exchange tube mounting holes 2 have flanges. Plate fins in the same group threaded onto the same heat exchange tube 4 are connected or fixed by the tube sheet 8.

[0019] The heat exchanger consists of sandwich-structured plate fins, heat exchange tubes 4, and a sealing layer 9 filling the outside of the heat exchange tubes 4. Protective plates 3 enclose the heat-conducting plates 1, and the sealing layer 9 also encloses the heat exchange tubes 4 and the heat-conducting plate portions near the heat exchange tubes, thereby isolating the heat exchanger from the external heat exchange fluid medium. One preferred method is to press the composite plate fins using a press to form a plate structure on the surface of the plate fins that enhances heat exchange and facilitates ash and condensate removal.

[0020] The heat exchanger consists of a first heat exchange medium (external fluid) flowing through the outer side of the plate fins and a second heat exchange medium (internal fluid) flowing through the inside of the heat exchange tube 4. The protective plate 3 contacts the first heat exchange medium (external fluid), generating heat exchange. The collected heat or cold is transferred to the inner heat-conducting plate 1, which in turn transfers the heat or cold to the heat exchange tube 4, which then transfers the heat or cold to the second heat exchange medium (internal fluid). The sealing layer 9 is made of a corrosion-resistant and wear-resistant sealing material, sealing the heat exchange tube 4 and isolating it from the first heat exchange medium (external fluid) during operation, thus preventing corrosion and wear. This heat exchanger can solve environmental heat exchange needs such as those in coal-fired boiler flues.

[0021] Obviously, this utility model is not limited to the preferred embodiments described above. Various modifications and improvements can be made within the spirit of the claims and specification of this utility model to solve the same technical problem and achieve the expected technical effect; therefore, these will not be repeated. All solutions that can be directly or indirectly conceived by those skilled in the art from the disclosure of this utility model, as long as they are within the spirit of the claims, also fall within the protection scope of this utility model.

Claims

1. A plate fin comprising a heat-conducting plate (1), a plurality of heat exchange tube mounting holes (2) provided on the heat-conducting plate (1), characterized in that, It also has a protective plate (3) wrapped around the outside of the heat-conducting plate (1), and the outer surface of the heat-conducting plate (1) and the protective plate (3) are pressed into a corrugated shape after being assembled.

2. The plate fin according to claim 1, characterized in that, The heat exchange tube mounting hole (2) has a flange.

3. A heat exchanger comprising a plurality of plate fins and a plurality of heat exchange tubes (4) connected to the plate fins, wherein the plate fins of the same group are threaded onto the same row of heat exchange tubes (4), characterized in that, The plate fins include a heat-conducting plate (1), a plurality of heat exchange tube mounting holes (2) provided on the heat-conducting plate (1), and a protective plate (3) wrapped around the outside of the heat-conducting plate (1). The outer surface of the heat-conducting plate (1) and the protective plate (3) are pressed into a corrugated shape after being assembled. It also has a first tube sheet (5) and a second tube sheet (6) located on both sides of the same plate fins, an inlet header (7) connected to the first tube sheet (5), an outlet header (8) connected to the second tube sheet (6), and a sealing layer (9) wrapped around the outside of the heat exchange tube (4). The first tube sheet (5) and the second tube sheet (6) are both connected to the heat exchange tube (4).

4. The heat exchanger according to claim 3, characterized in that, The heat exchange tube mounting hole (2) has a flange.

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