A high-temperature gas-liquid flat fin tube heat exchanger

Abstract

The present invention relates to a high-temperature gas-liquid flat fin tube heat exchanger, which primarily comprises a gas-phase heat exchange channel and a liquid-phase heat exchange pipeline. The gas-phase heat exchange channel comprises an air inlet interface, a heat exchange housing, a diverting flow channel, and an air outlet interface. The liquid-phase heat exchange pipeline comprises an inlet manifold, a diverter pipe, flat-fin heat exchange tubes, a converging pipe, an outlet manifold, and a flow divider. The heat exchange housings are arranged in parallel and connected end to end to form a multi-pass airflow channel. Flat heat exchange fin tubes are arranged in rows along the flow direction within the heat exchange housing. The liquid phase is evenly distributed into the flat-fin tubes via the liquid-phase inlet manifold and the transverse diverter pipes. Gas flows in the gaps between adjacent heat exchange surfaces, achieving multi-pass countercurrent gas-liquid heat exchange. Because more fins can be arranged outside the flat tubes, the gas side has a higher heat transfer coefficient. Simultaneously, multi-pass pure countercurrent heat exchange is achieved, achieving higher heat exchange efficiency and significant economic benefits. The heat exchanger will be widely used in high-temperature gas-liquid medium heat exchange processes.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, in particular to a high-temperature gas-liquid flat fin tube heat exchanger. Background Art

[0002] A heat exchanger is a device that transfers and exchanges heat between two or more media at different temperatures, also known as a heat exchanger. Common types of heat exchangers include shell and tube heat exchangers, plate heat exchangers, double-tube heat exchangers, spiral tube heat exchangers, and heat pipe heat exchangers. The evaporator and condenser in the air conditioners commonly seen in daily life are also a type of heat exchanger. These heat exchangers have different characteristics and are suitable for specific occasions. In addition, they can also be classified according to the phase state of the fluid, mainly including: liquid-liquid, liquid-gas, liquid-vapor, gas-gas, gas-vapor, gas-liquid and other types; among them, gas-liquid heat exchange has the characteristic that the thermal resistance on the gas side is much greater than the thermal resistance on the liquid side. Therefore, fins can be added to increase the heat exchange area to reduce the thermal resistance on the gas side and enhance heat exchange.

[0003] Currently, the main heat exchanger used for gas-liquid heat exchange is the serpentine finned tube heat exchanger. In a serpentine tube heat exchanger, the heat transfer tubes are arranged in a serpentine shape, with the working fluid inside the tubes being liquid and the working fluid outside the tubes being gas. Because the heat transfer coefficient on the gas side is significantly lower than that on the liquid side, fins of various types are usually arranged on the outside of the tube wall to increase the heat transfer area and reduce thermal resistance. This type of heat exchanger is mainly used in various air coolers and economizers and energy savers on industrial furnaces and boilers. However, this heat exchanger also has some problems during use. The main ones are: ① The liquid has a longer flow path, which can achieve a larger inlet and outlet temperature difference, but the gas flow path is shorter, which limits the temperature rise of the gas. ② Because this type of heat exchange tube is a circular tube structure, the finning ratio is usually less than 10. The heat transfer coefficients on the gas and liquid sides generally differ by 50-100 times. Therefore, even if fins are added to the gas side, the resistance of the heat transfer process is still on the gas side. ③ The gas and liquid flow cross, further reducing the heat transfer coefficient. ④ When the gas-liquid temperature is very high, the free expansion problem of the structure cannot be solved. Therefore, the main technical problems that need to be solved at present are: ① changing the structure of the heat exchange tube to further increase the finning rate on the gas side to reduce the thermal resistance on the gas side and obtain the maximum heat transfer coefficient; ② changing the overall structural layout to enable multi-pass pure countercurrent heat exchange between gas and liquid; ③ allowing the high-temperature heat exchange tube and box to expand freely to eliminate thermal stress.

[0004] The current power grid system has a large peak-to-valley difference between daytime and nighttime due to the different production and living cycles. Since the price of valley electricity is very low, using valley electricity to heat molten salt to a high temperature for heat storage at night, and then releasing the stored heat from the high-temperature molten salt during the peak hours of electricity and steam consumption during the day to meet various process requirements can achieve better economic benefits, and is currently gaining more and more attention. Heating air with high-temperature molten salt can produce very high-temperature air, which can be used for spray drying, high-temperature pyrolysis of organic matter, combustion of low-calorific value fuels, and treatment of toxic and harmful gases. The heat exchanger of the present invention is particularly suitable for high-temperature molten salt-air heat exchange. It not only has high heat transfer efficiency and can solve the expansion problem, but also obtains high-temperature wind above 400°C, which can be applied to a variety of high-temperature process steps. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: In response to the above problems and the deficiencies of the existing technology, the present invention provides a high-temperature gas-liquid flat fin tube heat exchanger, which further increases the gas-side heat exchange area to improve the overall heat transfer coefficient and solves the thermal expansion problem during the heat exchange process.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a high-temperature gas-liquid flat fin tube heat exchanger, including a gas-phase heat exchange channel and a liquid-phase heat exchange pipeline, the gas-phase heat exchange channel including an air inlet interface, a heat exchange box, a turning flow channel and an air outlet interface, the boxes are multiple and arranged in parallel along the air flow direction, adjacent heat exchange boxes are connected to each other through the turning flow channel, the inlet of the heat exchange box is connected to the air inlet interface, and the outlet of the heat exchange box is connected to the air outlet interface;

[0007] The liquid-phase heat exchange pipeline includes an inlet main pipe, a diverter pipe, a flat heat exchange tube, a heat exchange fin, a collector pipe, an outlet main pipe and a flow divider. The inlet main pipe is placed at the inlet end of the heat exchange box. There are multiple diverter pipes that are arranged in parallel, and both ends are sealed to pass through the heat exchange box and are fixedly connected to the inlet main pipe. There are multiple flat heat exchange tubes that are arranged in an array along the flow direction in the heat exchange box. The inlet end of the flat heat exchange tube is fixedly connected to the diverter pipe, and the outlet end of the flat heat exchange tube is fixedly connected to the collector pipe. There are multiple collector pipes that are arranged in parallel, and both ends are sealed to pass through the heat exchange box and are fixedly connected to the outlet main pipe. The outlet main pipe is placed at the outlet end of the heat exchange box.

[0008] In some preferred embodiments, there are a plurality of heat exchange fins which are fixedly placed on both sides of the flat heat exchange tube along the flow direction, and the heat exchange fins are located in the heat exchange box.

[0009] In some preferred embodiments, the heat exchange fins are at least one of straight-slit fins and corrugated fins, and the straight-slit fins are spaced apart with a plurality of raised slits and arranged in a staggered manner. The straight-slit fins are used to generate turbulence to the gas and destroy the thermal boundary layer. The corrugated fins are symmetrically fixed on both sides of the flat heat exchange tube, and a gradually contracting and expanding scale-shaped flow channel is formed between two adjacent corrugated fins. The scale-shaped flow channel is used to accelerate and decelerate the airflow to obtain strong disturbance.

[0010] In some preferred embodiments, the diverter tube is provided with a plurality of semicircular slits with a width equal to the inner height of the flat heat exchange tube spaced axially thereon, the flat heat exchange tube inlet end is provided with a through hole, the diverter tube intersects vertically with the through hole at the inlet end of the flat heat exchange tube, the semicircular slit is connected to the flat heat exchange tube, and the semicircular slit is used to divert the liquid into the flat heat exchange tube.

[0011] In some preferred embodiments, the manifold is axially spaced apart with a plurality of semicircular slits having a width equal to the height of the inner side of the flat heat exchange tube, the outlet end of the flat heat exchange tube is provided with a through hole, the manifold intersects vertically with the through hole at the outlet end of the flat heat exchange tube, the semicircular slits are connected to the flat heat exchange tube, and the semicircular slits are used to converge the liquid into the manifold.

[0012] In some preferred embodiments, flow dividers are provided in both the inlet manifold and the outlet manifold, and the flow dividers are used to reverse the direction of the medium in the flat heat exchange tubes in two adjacent heat exchange boxes.

[0013] In some preferred embodiments, expansion joints are arranged at both ends of the heat exchange box, and the expansion joints are arranged perpendicular to the axial direction of the heat exchange box and fixedly and sealedly connected thereto.

[0014] In some preferred embodiments, the outer surface of the heat exchange box is covered with an insulation layer.

[0015] In some preferred embodiments, a closable inspection door is provided on the rear plate of the diverting flow channel.

[0016] The beneficial effects of the present invention are:

[0017] 1. The liquid medium and the gas medium can flow in parallel and opposite directions, realizing pure counter-flow between the two media, and obtaining a larger average heat transfer temperature difference.

[0018] 2. The flow directions of liquid and gaseous media are changed respectively by the flow partitions on the distribution main pipe and the turning channels on the heat exchange box, so as to realize multi-pass heat exchange between the media and make the media have a larger inlet and outlet temperature difference.

[0019] 3. Flat finned tubes are used, and fins of different positions and shapes are arranged on the side of the flat heat exchange tubes, which increases the heat exchange area on the gas medium side and strengthens the disturbance of the gas boundary layer, reducing the thermal resistance on the gas side, thereby obtaining the maximum heat transfer coefficient.

[0020] 4. An expansion joint is arranged on the heat exchange box, which allows both the gas and liquid sides to expand freely, eliminating the thermal stress generated during the heat exchange process. It is suitable for heat exchange between high-temperature media. For example, high-temperature molten salt can be used to obtain high-temperature air.

[0021] 5. The arrangement of the flat finned tubes is fixed by using the medium distribution and collection cross pipes, and the inlet and outlet distribution main pipes are used as the supporting structure of the entire heat exchanger, saving materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below with reference to the accompanying drawings and examples.

[0023] Figure 1 Schematic diagram of the overall structure of the heat exchanger of the present invention;

[0024] Figure 2 To follow Figure 1 A cross-sectional view of the embodiment shown along line AA;

[0025] Figure 3 To follow Figure 1 A cross-sectional view of the embodiment shown along line BB;

[0026] Figure 4 To follow Figure 1 A cross-sectional view of the embodiment shown along line CC;

[0027] Figure 5 To follow Figure 1 A cross-sectional view of the embodiment shown along line DD;

[0028] Figure 6 Schematic diagram of the structure and connection structure of the manifold, flat heat exchange tube and corrugated fin. Figure 1 ;

[0029] Figure 7 Schematic diagram of the structure and connection structure of the manifold, flat heat exchange tube and corrugated fin. Figure 2 ;

[0030] Figure 8 Schematic diagram of the structure and connection structure of the diverter tube, flat heat exchange tube and straight slot fin Figure 1 ;

[0031] Figure 9 Schematic diagram of the structure and connection structure of the diverter tube, flat heat exchange tube and straight slot fin Figure 2 .

[0032] In the figure: 1, gas-phase heat exchange channel, 11, air inlet interface, 12, heat exchange box, 13, turning channel, 14, air outlet interface, 15, expansion joint;

[0033] 21. Outlet main pipe, 22. Converging pipe, 23. Flat heat exchange tube, 24. Heat exchange fin, 241. Straight slot fin, 242. Corrugated fin, 25. Diverter pipe, 26. Inlet main pipe, 27. Flow divider. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with the embodiments:

[0035] The present invention is not limited to the following specific embodiments. Based on the disclosure of the present invention, a person skilled in the art may adopt a variety of other specific embodiments to implement the present invention. Any simple changes or modifications made to the design structure and concept of the present invention fall within the scope of protection of the present invention. It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other unless they conflict.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0037] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0038] like Figures 1 to 9As shown, a high-temperature gas-liquid flat fin tube heat exchanger includes a gas-phase heat exchange channel 1, a liquid-phase heat exchange pipeline and an insulation layer. The gas-phase heat exchange channel 1 includes an air inlet interface 11, a heat exchange box 12, a turning channel 13, an air outlet interface 14 and an expansion joint 15;

[0039] The liquid phase heat exchange pipeline includes an inlet manifold 26, a diverter pipe 25, a flat heat exchange tube 23, a heat exchange fin 24, a manifold 22, an outlet manifold 21 and a flow divider 27;

[0040] There are multiple heat exchange boxes 12 and they are arranged parallel to each other along the air flow direction. The inlet of the heat exchange box 12 at the head end is connected to the air inlet interface 11, the two adjacent heat exchange boxes 12 are connected through the turning channel 13, and the outlet of the heat exchange box 12 at the tail end is connected to the air outlet interface 14.

[0041] The inlet main pipe 26 is placed on both sides of the inlet end of the heat exchange box 12. There are multiple branch pipes 25 that are arranged in parallel, and both ends are sealed to pass through the heat exchange box 12 and are fixedly connected to the inlet main pipe 26. There are multiple flat heat exchange tubes 23 that are arranged in an array along the flow direction in the heat exchange box 12. There are n flat heat exchange tubes 23 arranged horizontally and m flat heat exchange tubes 23 arranged vertically on the cross section of the heat exchange box 12. The inlet end of the flat heat exchange tube 23 is fixedly connected to the branch pipe 25, and the outlet end of the flat heat exchange tube 23 is fixedly connected to the manifold 22. There are multiple manifolds 22 that are arranged in parallel, and both ends are sealed to pass through the heat exchange box 12 and are fixedly connected to the outlet main pipe 21. The outlet main pipe 21 is placed at the outlet end of the heat exchange box 12, and the insulation layer covers the outer surface of the heat exchange box 12 and the outside of all other pipes.

[0042] There are multiple heat exchange fins 24 and they are fixedly placed on both sides of the flat heat exchange tube 23 along the flow direction. The heat exchange fins 24 are located in the heat exchange box 12. The heat exchange fins 24 are at least one of straight slit fins 241 and corrugated fins 242.

[0043] There are multiple corrugated fins 242 and they are symmetrically arranged on both sides of the flat heat exchange tube 23 along the flow direction, forming a gradually shrinking and expanding scale-shaped flow channel, which causes the gas to generate strong turbulence to destroy the thermal boundary layer and enhance the heat exchange effect.

[0044] There are multiple straight slot fins 241 and they are placed on both sides of the flat heat exchange tube 23 along the flow direction. There are multiple raised slots spaced apart on the straight slot fins 241 and they are staggered, so that the gas generates turbulence to destroy the thermal boundary layer, thereby enhancing heat exchange and improving the heat transfer coefficient.

[0045] The confluence pipe 22 is axially spaced apart with a plurality of semicircular grooves having a width equal to the inner height of the flat heat exchange tube 23. At the same time, a through hole is opened at the outlet end of the flat heat exchange tube 23. The confluence pipe 22 intersects vertically with the inlet through hole of the flat heat exchange tube 23. The semicircular grooves are connected to the flat heat exchange tube 23, and the liquid is converged into the flat heat exchange tube 23, thereby achieving a good confluence effect.

[0046] The diverter tube 25 is axially spaced apart with a plurality of semicircular grooves of a width equal to the height of the inner side of the flat heat exchange tube 23. At the same time, a through hole is opened at the inlet end of the flat heat exchange tube 23. The diverter tube 25 intersects vertically with the inlet through hole of the flat fin tube. The semicircular grooves are connected to the flat fin tube and divert the liquid into the flat heat exchange tube 23, thereby achieving good diversion.

[0047] Expansion joints 15 are arranged at both ends of the heat exchange box 12. The expansion joints 15 are arranged perpendicular to the axial direction of the heat exchange box 12 and are fixedly and sealedly connected to the heat exchange box 12 to meet the free expansion of the box and eliminate thermal stress.

[0048] An inspection door that can be opened and closed is provided on the rear plate of the diverting flow channel 13 .

[0049] Flow dividers 27 are provided in both the inlet manifold 26 and the outlet manifold 21 . The flow dividers 27 are used to reverse the direction of the medium in the flat heat exchange tubes 23 in the two adjacent heat exchange boxes 12 .

[0050] The working process of the high-temperature gas-liquid flat fin tube heat exchanger of the present invention is as follows:

[0051] First, assume that the liquid medium is a hot fluid that needs to release heat and cool down, and the gas medium is a fluid that needs to be heated up. The high-temperature liquid medium flows from the distribution main pipe into the liquid diversion cross pipes of each row, then flows into the flat fin tubes, and then into the liquid converging cross pipes, and finally flows out through the converging pipe into the main pipe;

[0052] The gaseous medium enters from the lower side of the heat exchanger shell. The gap between the two heat exchange planes serves as a channel for the gaseous medium. After absorbing heat throughout the entire process, the high-temperature gas flows out from the upper side of the shell. The two fluid media flow in parallel and opposite directions, forming a pure counter-current heat exchange method. The flow direction of the liquid and gas media is changed by the baffles on the distribution main pipe and the diverting flow channels on both ends of the heat exchange box, respectively, to achieve multi-pass heat exchange between the media.

[0053] The above description of the preferred embodiments of the present invention is intended to serve as a guide. Based on the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A high-temperature gas-liquid flat fin tube heat exchanger, comprising a gas phase heat exchange channel (1) and a liquid phase heat exchange pipeline, characterized in that The gas-phase heat exchange channel (1) comprises an air inlet interface (11), a heat exchange box (12), a steering channel (13) and an air outlet interface (14); the box (12) has multiple components and is arranged in parallel along the airflow direction; two adjacent heat exchange boxes (12) are connected to each other through the steering channel (13); the inlet of the heat exchange box (12) is connected to the air inlet interface (11), and the outlet of the heat exchange box (12) is connected to the air outlet interface (14); the liquid-phase heat exchange pipeline comprises an inlet manifold (26), a diverter pipe (25), a flat heat exchange tube (23), a heat exchange fin (24), a confluence pipe (22), an outlet manifold (21) and a flow divider (27); the inlet manifold ( 26) is placed at the inlet end of the heat exchange box (12), the diverter pipes (25) are multiple and arranged in parallel, and both ends are sealed and pass through the heat exchange box (12) and are fixedly connected to the inlet main pipe (26), the flat heat exchange tubes (23) are multiple and arranged in an array along the flow direction in the heat exchange box (12), the inlet end of the flat heat exchange tube (23) is fixedly connected to the diverter pipe (25), the outlet end of the flat heat exchange tube (23) is fixedly connected to the manifold (22), the manifold (22) is multiple and arranged in parallel, and both ends are sealed and pass through the heat exchange box (12) and are fixedly connected to the outlet main pipe (21), and the outlet main pipe (21) is placed at the outlet end of the heat exchange box (12); The heat exchange fins (24) are provided in plurality and are fixedly disposed on both sides of the flat heat exchange tube (23) along the flow direction, and the heat exchange fins (24) are located in the heat exchange box (12); A flow divider (27) is provided in each of the inlet manifold (26) and the outlet manifold (21), and the flow divider (27) is used to reverse the medium in the flat heat exchange tubes (23) in the two adjacent heat exchange boxes (12); Expansion joints (15) are arranged at both ends of the heat exchange box (12), and the expansion joints (15) are arranged perpendicular to the axial direction of the heat exchange box (12) and are fixedly and sealedly connected thereto; The liquid medium and the gaseous medium in the heat exchanger can flow in parallel and opposite directions, realizing pure reverse flow between the two media. The flow directions of the liquid medium and the gaseous medium are respectively changed through the flow partition plate (27) on the distribution main pipe and the turning channel on the heat exchange box (12), realizing multi-pass heat exchange between the media.

2. A high-temperature gas-liquid flat fin tube heat exchanger according to claim 1, characterized in that The heat exchange fins (24) are at least one of straight slit fins (241) and corrugated fins (242). The straight slit fins (241) are spaced apart with a plurality of raised slits and arranged in a staggered manner. The straight slit fins (241) are used to generate turbulence to the gas and destroy the thermal boundary layer. The corrugated fins (242) are symmetrically fixed on both sides of the flat heat exchange tube (23). A gradually contracting and expanding scale-shaped flow channel is formed between two adjacent corrugated fins (242). The scale-shaped flow channel is used to accelerate and decelerate the airflow to obtain strong disturbance.

3. A high-temperature gas-liquid flat fin tube heat exchanger according to claim 1, characterized in that The diverter tube (25) is provided with a plurality of semicircular slits having a width equal to the height of the inner side of the flat heat exchange tube (23) spaced apart in the axial direction. A through hole is provided at the inlet end of the flat heat exchange tube. The diverter tube (25) intersects vertically with the through hole at the inlet end of the flat heat exchange tube (23). The semicircular slit is connected to the flat heat exchange tube (23). The semicircular slit is used to divert liquid to the flat heat exchange tube (23).

4. A high-temperature gas-liquid flat fin tube heat exchanger according to claim 3, characterized in that The confluence pipe (22) is provided with a plurality of semicircular slits having a width equal to the height of the inner side of the flat heat exchange tube (23) spaced apart in the axial direction. The outlet end of the flat heat exchange tube (23) is provided with a through hole. The confluence pipe (22) intersects vertically with the through hole at the outlet end of the flat heat exchange tube (23). The semicircular slit is connected to the flat heat exchange tube (23). The semicircular slit is used to converge the liquid into the confluence pipe (22).

5. The high-temperature gas-liquid flat fin tube heat exchanger according to claim 1, characterized in that The outer surface of the heat exchange box (12) is covered with a thermal insulation layer.

6. A high-temperature gas-liquid flat fin tube heat exchanger according to any one of claims 1 to 5, characterized in that An inspection door that can be opened and closed is provided on the rear plate of the diverting flow channel (13).

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