High finned tube heat exchanger for heat exchange of low-pressure section of compressed air energy storage power station

Abstract

The utility model relates to a high finned tube heat exchanger for heat exchange of a low-pressure section of a compressed air energy storage power station, which comprises a tube box, one side of the tube box is connected with a tube plate, one side, far away from the tube box, of the tube plate is connected with a shell, a plurality of groups of tube cores are arranged in the shell, the tube cores are connected with pipeline connectors on one side, far away from the tube box, of the tube plate, and the tube cores are provided with aluminum fins. The high-fin finned tube is adopted to replace a light tube or a single-metal low-fin tube, the specific heat exchange area of the heat exchanger can be 3-5 times that of a current mainstream scheme, the heat exchange area of a single heat exchanger can reach ten thousand square meters, the size and the number of devices are reduced, the size reasonability of the heat exchanger is guaranteed, and the manufacturing and mounting requirements are met; and one section of the tube bundle structure is fixed on the tube plate, and the other end of the tube bundle structure can move freely, so that the condition of core-pulling cleaning is met while thermal deformation is adapted.

Description

Technical Field

[0001] This utility model relates to the field of energy storage and power generation technology, and in particular to a high-finned tube heat exchanger for heat exchange in the low-pressure section of a compressed air energy storage power station. Background Technology

[0002] In recent years, the rapid development of renewable energy in my country has created a demand for long-term energy storage technologies for the power system. One of the mainstream technologies in China is non-combustion compressed air energy storage, which boasts higher energy conversion efficiency and economic benefits, and is currently the most promising large-scale physical energy storage technology. Compressed air has also become the most prominent technological route in the latest batch of national new energy storage pilot demonstration projects.

[0003] In current non-combustion compressed air energy storage systems, heat exchangers play a crucial role in system energy efficiency and economy. They are responsible not only for efficiently transferring heat during compression and expansion but also for influencing the overall stable operation and lifespan of the system. However, current heat exchanger designs for compressed air energy storage power plants are similar to those in general thermal power plants, failing to design more suitable heat exchangers based on the characteristics of the compressed air energy storage medium and parameters. Currently, 100-megawatt-level compressed air energy storage power plant units generally adopt a four-stage compression and three-stage expansion configuration, with pressurized water typically used as the heat storage medium. In the low-pressure section, i.e., when the air pressure does not exceed 2.5 MPa, specifically referring to the first two stages on the compression side and the last stage on the expansion side, the main heat exchanger designs are bare tube U-shaped hairpin type and straight tube low-finned tube type.

[0004] When designing and selecting heat exchangers based on traditional thermal power plant experience, the following issues mainly arise:

[0005] 1. The issue of the number of heat exchangers caused by low heat transfer coefficients:

[0006] Due to limitations in air properties, the heat exchanger coefficient in the low-pressure section of a compressed air energy storage power station is typically between 200 and 300 W / m²·℃. When stringent air-side pressure drop requirements are imposed, air velocity constraints can further reduce the heat exchange coefficient to less than 100 W / m²·℃. In contrast, in conventional thermal power plants, the heat exchange medium is water (steam), with a heat exchange coefficient generally exceeding 1000 W / m²·℃. This low heat exchange coefficient means that the area required for heat exchange in the low-pressure section is several times larger than that in the high-pressure section. Furthermore, manufacturing limitations on heat exchanger tube length and shell diameter result in a limited area for a single heat exchanger. Using bare tube heat exchangers in the low-pressure section further increases the required area for heat exchanger arrangement.

[0007] Even when using low-finned tube heat exchangers, the reduction in the number of heat exchangers is limited because the fin ratio of low-finned tubes is generally around 2.5.

[0008] 2. Structural design difficulties caused by countercurrent heat transfer and tube bundle cleaning:

[0009] In compressed air energy storage power stations, heat exchangers are responsible for storing and converting the heat of compression during the compression process. To improve the unit's energy conversion efficiency, the temperatures of the air and the heat exchange medium need to be as close as possible in the thermal design, typically 10–15°C in engineering practice. To meet the requirements of small temperature difference heat exchange, a counter-current heat exchange method is required. Air is not a clean heat exchange medium, and the cleaning methods for air-side fouling must be fully considered in the design of heat exchangers in compressed air energy storage power stations. Currently, the mainstream low-finned tube schemes in the low-pressure section of heat exchangers in compressed air energy storage power stations, whether the new U-tube hairpin type or the straight tube low-fin type, cannot achieve core removal and cleaning of the tube bundles. While traditional U-tube or floating head heat exchangers can achieve core removal and cleaning in terms of structure, they are difficult to use for pure counter-current heat exchange, and their heat exchange efficiency is much lower than the former, so they are rarely used in large-scale compressed air energy storage power stations. Utility Model Content

[0010] To address the limitations of manufacturing capabilities in heat exchanger tube length and heat exchanger shell diameter, which result in a limited area of ​​a single heat exchanger, and the inability to simultaneously achieve core-pulling cleaning and pure counter-current heat exchange, a high-finned tube heat exchanger for low-pressure section heat exchange in compressed air energy storage power stations is proposed.

[0011] The technical solution of this utility model is: a high-finned tube heat exchanger for heat exchange in the low-pressure section of a compressed air energy storage power station, including a tube box, which is a box with one end open, the open side being connected to the tube sheet, and the side of the tube sheet away from the tube box being connected to the shell.

[0012] The shell is a hollow cylindrical shape, and multiple sets of tube cores are arranged inside the shell. The tube cores are connected to the pipe interface on the side of the tube sheet away from the tube box, and the tube cores are provided with aluminum fins.

[0013] Preferably, the core is continuously wound back and forth along the central axis of the housing.

[0014] Preferably, the pipe box is provided with an outlet pipe at the top and an inlet pipe at the bottom.

[0015] Preferably, the core tube is a U-shaped heat exchange tube, and the aluminum fins are disposed on the outer surface of the U-shaped heat exchange tube except at the U-shaped bend.

[0016] Preferably, the U-shaped heat exchange tube is a continuous whole without splicing.

[0017] Preferably, a sealing plate is provided at the U-shaped bend of the inner core of the housing.

[0018] Preferably, the top of the housing is provided with an air inlet pipe, and the bottom of the housing is provided with an air outlet pipe.

[0019] Preferably, the air inlet pipe and the air outlet pipe are arranged symmetrically in pairs about the central axis of the housing.

[0020] Preferably, the core includes multiple core processes, with two core processes forming a rectangular module in a back-and-forth motion. The core processes are arranged from bottom to top, and the arrangement direction is opposite to the airflow direction.

[0021] Preferably, the number of the die process (311) is not less than 8 and not more than 24.

[0022] The beneficial effects of this utility model are as follows: This utility model provides a high-finned tube heat exchanger for low-pressure section heat exchange in compressed air energy storage power stations; by using high-finned tubes instead of bare tubes or single-metal low-finned tubes, the heat exchanger's heat exchange area can be 3 to 5 times that of the current mainstream schemes, allowing the heat exchange area of ​​a single heat exchanger to reach tens of thousands of square meters, reducing equipment size and quantity, ensuring the rationality of heat exchanger size, and meeting manufacturing and installation requirements; furthermore, the tube bundle structure is fixed at one end to the tube sheet, while the other end can move freely, adapting to thermal deformation while also providing conditions for core removal and cleaning; the multi-pass tube bundle arrangement scheme and the corresponding shell-side medium flow scheme can achieve a pure counter-current heat exchange effect; a sealing plate 5 is set at the tail of the high-finned tube core 3 to prevent fluid short-circuiting and affecting heat exchange. Attached Figure Description

[0023] Figure 1 This is a front view schematic diagram of the structure of the high-finned tube heat exchanger of this utility model;

[0024] Figure 2 This is a schematic diagram of the rectangular module structure of the high-finned tube heat exchanger of this utility model.

[0025] The component names corresponding to the various reference numerals in the diagram are as follows:

[0026] 1. Tube box; 11. Outlet pipe; 12. Inlet pipe; 2. Tube sheet; 3. Tube core; 31. Rectangular module; 311. Tube core flow; 312. Tube core flow; 4. Housing; 41. Air inlet pipe; 42. Air outlet pipe; 5. Sealing plate; Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. This embodiment is based on the technical solution of the present invention and provides detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.

[0028] refer to Figure 1As shown, this utility model provides a high-finned tube heat exchanger for heat exchange in the low-pressure section of a compressed air energy storage power station, including a tube box 1. The tube box 1 is a box with one end open. The open side is connected to the tube sheet 2. The side of the tube sheet 2 away from the tube box 1 is connected to the shell 4. The tube box 1 and the tube sheet 2, and the tube sheet 2 and the shell 4 can be connected by peripheral welding or flange connection. After the connection is completed, two independent chambers are formed.

[0029] The shell 4 is a hollow cylindrical shape. Inside the shell 4, a core 3 is provided, which is composed of multiple sets of U-shaped heat exchange tubes that are continuously wound back and forth along the central axis of the shell. The outer surface of the heat exchange tubes (except for the U-shaped bends) is covered or welded with aluminum fins. The heat exchange tubes are continuous and splicing is not allowed.

[0030] The core tube 3 is connected to the pipe interface on the side of the tube sheet 2 away from the tube box 1, and the core tube 3 and the tube sheet 2 are connected by a strength weld;

[0031] Specifically, the top of the tube box 1 is provided with an outlet pipe 11 and the bottom is provided with an inlet pipe 12. The heat storage medium enters the tube box through the outlet pipe 11 and then flows through the tube core 3.

[0032] Specifically, the top of the housing 4 is provided with multiple air inlet pipes 41, and the bottom of the housing 4 is provided with multiple air outlet pipes 42. The air inlet pipes 41 and air outlet pipes 42 are symmetrically arranged in pairs about the central axis of the housing 4. The air inlet pipes 41 and air outlet pipes 42 enable air to pass evenly across the tube core 3, thereby performing heat exchange.

[0033] A sealing plate 5 is installed at the U-shaped bend of the tube core 3 at the end of the shell 4 away from the tube sheet 2. The sealing plate 5 prevents air short circuit and affects the heat transfer coefficient.

[0034] refer to Figure 2 As shown, the core 3 has a multi-pass arrangement inside. There is a core pass 311 from one end of the shell 4 to the other. The core passes are arranged in multiple passes, with no less than 8 passes and no more than 24 passes. Every two core passes 311 and 312 form a rectangular module 31 in the shell 4. The heat storage medium passes from bottom to top through the bottom first core pass. The air flow direction is from top to bottom. The arrangement direction of each core pass 311 is opposite to the air flow direction. The heat exchange efficiency can achieve the effect of pure counter-current heat exchange.

[0035] The beneficial effects of this heat exchanger are as follows: A high-finned tube heat exchanger for low-pressure section heat exchange in compressed air energy storage power stations uses highly finned tubes instead of bare tubes or single-metal low-finned tubes, which can make the heat exchanger's heat exchange area 3 to 5 times that of the current mainstream schemes, allowing the heat exchange area of ​​a single heat exchanger to reach tens of thousands of square meters, reducing equipment size and quantity, ensuring the rationality of heat exchanger size, and meeting manufacturing and installation requirements; moreover, the tube bundle structure is fixed at one end to the tube sheet, while the other end can move freely, which not only adapts to thermal deformation but also provides the conditions for core removal and cleaning. The multi-pass tube bundle arrangement scheme and the corresponding shell-side medium flow scheme can achieve the effect of pure countercurrent heat exchange. A sealing plate 5 is set at the tail of the high-finned tube core 3 to prevent fluid short circuit and affect heat exchange.

[0036] It should be noted that the terms "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. "A plurality of" means two or more. "Installed," "connected," and "joined" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection.

[0037] The above description is merely a preferred embodiment of this utility model and is not intended to limit this utility model in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from this utility model, and these improvements and additions should also be considered within the protection scope of this utility model. Any modifications, alterations, and equivalent changes made by those skilled in the art without departing from the spirit and scope of this utility model using the disclosed technical content are equivalent embodiments of this utility model. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of this utility model are still within the scope of the technical solution of this utility model.

Claims

1. A high-finned-tube heat exchanger for low-pressure section heat exchange in a compressed air energy storage power station, characterized in that, Includes a tube box (1), which is a box with one end open. The open side is connected to the tube plate (2), and the side of the tube plate (2) away from the tube box (1) is connected to the shell (4). The shell (4) is a hollow cylindrical shape. Multiple sets of tube cores (3) are provided inside the shell (4). The tube cores (3) are connected to the pipe interface on the side of the tube sheet (2) away from the tube box (1). The tube cores (3) are provided with aluminum fins. The core (3) is a U-shaped heat exchange tube that is continuously wound back and forth along the central axis of the shell (4); The core (3) is a U-shaped heat exchange tube, and the aluminum fins are arranged on the outer surface of the U-shaped heat exchange tube except at the U-shaped bend; The housing (4) has a sealing plate (5) installed at the U-shaped bend of the inner core (3); The core (3) includes multiple core flows (311, 312), and each pair of core flows constitutes a rectangular module (31). The tube side medium flows from bottom to top, and the shell side air flows from top to bottom, realizing pure countercurrent heat exchange.

2. The high-finned-tube heat exchanger for low-pressure section heat exchange in a compressed air energy storage power station according to claim 1, characterized in that, The top of the pipe box (1) is provided with an outlet pipe (11) and the bottom is provided with an inlet pipe (12).

3. The high-finned-tube heat exchanger for low-pressure section heat exchange in a compressed air energy storage power station according to claim 1, characterized in that, The U-shaped heat exchange tube is a continuous, seamless unit.

4. The high-finned-tube heat exchanger for low-pressure section heat exchange in a compressed air energy storage power station according to claim 1, characterized in that, The housing (4) is provided with an air inlet pipe (41) at the top and an air outlet pipe (42) at the bottom.

5. The high-finned-tube heat exchanger for low-pressure section heat exchange in a compressed air energy storage power station according to claim 4, characterized in that, The air inlet pipe (41) and air outlet pipe (42) are symmetrically arranged in pairs with the central axis of the housing (4) as the axis of symmetry.

6. The high-finned-tube heat exchanger for low-pressure section heat exchange in a compressed air energy storage power station according to claim 1, characterized in that, The core (3) includes multiple core processes (311, 312). Every two core processes (311, 312) form a rectangular module (31) in a back-and-forth manner. The core processes (311, 312) are arranged from bottom to top, and the arrangement direction is opposite to the airflow direction.

7. The high-finned-tube heat exchanger for low-pressure section heat exchange in a compressed air energy storage power station according to claim 6, characterized in that, The number of the die process (311) shall be no less than 8 and no more than 24.

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