Waste heat recovery system of thermal power plant

Abstract

The waste heat recovery system of the thermal power plant comprises a cylinder, air inlet and outlet pipes are installed at the two ends of the cylinder and communicated with the interior of the cylinder, the side wall of the cylinder is open, a side plate is installed at the position of the side wall, one end of a connecting hose is communicated with the interior of a steam plate, and a preheating box is installed at the lower end of the cylinder. The upper end of the preheating box is open and extends to the inner bottom of the barrel, and a driving assembly for driving the steam plate to slide is mounted in the preheating box. The steam plate sprays steam to preheat the heat exchange tube, so that the surface temperature of the heat exchange tube gradually rises, rapid expansion or contraction caused by overlarge temperature difference is avoided, thermal stress caused by rapid temperature change is reduced, the heat exchange efficiency is improved, and the service life of equipment is prolonged; and the threaded rod is matched to drive the steam plate to slide in the cylinder body, so that uniform spraying of steam is ensured, uniform preheating of the heat exchange pipe is further realized, uneven heating of the heat exchange pipe is effectively avoided, and the stability of the heat exchange process is ensured.

Description

Technical Field

[0001] This utility model relates to the field of waste heat recovery technology, and in particular to a waste heat recovery system for thermal power plants. Background Technology

[0002] Currently, the waste heat from flue gas in thermal power plant boilers is rarely recovered. Flue gas loss accounts for the largest proportion of boiler heat loss. Therefore, if this waste heat can be recovered and used for centralized heating, the heating capacity of thermal power plants can be increased without consuming more coal, thereby achieving the goal of energy conservation and emission reduction.

[0003] Chinese utility model patent CN220582477U discloses a waste heat recovery heat exchanger for flue gas in a thermal power plant. This device, through the installation of a detachable cylindrical assembly and multiple sets of heat exchange components, facilitates disassembly, maintenance, and cleaning of the tubes, surrounding fins, and baffles after prolonged use. However, certain drawbacks exist in actual use. When the surface temperature of the heat exchange tubes is low during non-heat exchange, but the temperature difference changes rapidly during heat exchange, thermal stress may occur, leading to uneven expansion or contraction of the heat exchange tube material, which can cause cracks or damage to the outer wall of the tubes. Therefore, this paper proposes a waste heat recovery system for thermal power plants to address these issues. Utility Model Content

[0004] The purpose of this utility model is to address the shortcomings of existing technologies by proposing a waste heat recovery system for thermal power plants.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A waste heat recovery system for a thermal power plant includes a cylindrical body. Inlet and outlet pipes are installed at both ends of the cylindrical body and are connected to the interior of the body. The sidewalls of the cylindrical body are open and have side plates installed thereon. Multiple sets of heat exchange tubes, all arranged in an S-shape, are installed on the sidewalls of the side plates. Two sets of connecting pipes are installed on the outer walls of the side plates and are connected to both ends of the multiple sets of heat exchange tubes, respectively. A steam plate is slidably connected to the bottom of the cylindrical body. A connecting hose is installed on the sidewalls of the cylindrical body, with one end of the connecting hose connected to the interior of the steam plate. A preheating box is installed at the lower end of the cylindrical body, with its upper end open and extending to the bottom of the cylindrical body. A drive assembly for driving the steam plate to slide is installed inside the preheating box.

[0007] Preferably, the drive assembly includes a threaded rod rotatably connected to the bottom wall of the preheating box, a slider threadedly connected to the threaded section of the threaded rod, and a steam plate mounted on the upper end face of the slider.

[0008] Preferably, folding blades are installed on both outer walls of the slider, and the other end of the folding blades on both sides is in contact with the inner wall of the preheating box, and the side wall of the folding blades is in contact with the inner wall of the preheating box.

[0009] Preferably, a limiting rod is fixedly connected to the inner wall of the preheating box, and the slider is slidably connected to the threaded section of the limiting rod.

[0010] Preferably, the preheating box is connected to the cylinder by multiple sets of screws, the side plate is connected to the cylinder by multiple sets of screws, and sealing gaskets are installed on the side plate and the contact surfaces between the preheating box and the cylinder.

[0011] Preferably, a servo motor is fixedly connected to the side wall of the preheating box, and the end of the output shaft of the servo motor is fixedly connected to the threaded rod coaxially.

[0012] This utility model has the following beneficial effects:

[0013] 1. This utility model uses steam ejected from a steam plate to preheat the heat exchange tubes, ensuring that the surface temperature of the heat exchange tubes rises gradually. This avoids rapid expansion or contraction caused by excessive temperature differences, reduces thermal stress caused by rapid temperature changes, thereby improving heat exchange efficiency and extending the service life of the equipment. In conjunction with the threaded rod, the steam plate is driven to slide inside the cylinder, ensuring that the steam is ejected evenly, further achieving uniform preheating of the heat exchange tubes. This effectively avoids uneven heating of the heat exchange tubes and ensures the stability of the heat exchange process.

[0014] 2. By setting folding blades, this utility model effectively changes the flow path of flue gas, reduces the direct contact between impurities in the flue gas and the outer wall of the threaded rod, thereby preventing impurities from adhering to the threaded rod and ensuring the smooth rotation of the threaded rod. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the waste heat recovery system for thermal power plants proposed in this utility model;

[0016] Figure 2 for Figure 1 Schematic diagram of cross-section structure.

[0017] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure of the preheating box.

[0018] In the diagram: 1. Cylinder; 2. Inlet and outlet pipes; 3. Side plate; 4. Heat exchanger pipe; 5. Connecting pipe; 6. Screw 1; 7. Steam plate; 8. Connecting hose; 9. Screw 2; 10. Servo motor; 11. Folding blade; 12. Preheating box; 13. Threaded rod; 14. Limiting rod; 15. Slider. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0020] Reference Figure 1-3 The waste heat recovery system of a thermal power plant includes a cylinder 1. Both ends of the cylinder 1 are equipped with inlet and outlet pipes 2, which are connected to the interior of the cylinder 1. The side wall of the cylinder 1 is open, and a side plate 3 is installed there. Multiple sets of heat exchange tubes 4 are installed on the side wall of the side plate 3, all arranged in an S-shape. Two sets of connecting pipes 5 are installed on the outer wall of the side plate 3, respectively connected to both ends of the multiple sets of heat exchange tubes 4. A steam plate 7 is slidably connected to the bottom of the cylinder 1. A connecting hose 8 is installed on the side wall of the cylinder 1, with one end of the connecting hose 8 connected to the interior of the steam plate 7. A preheating box 12 is installed at the lower end of the cylinder 1, and its upper end is open and extends into the cylinder. Inside the bottom of the preheating box 12, there is a drive assembly that drives the steam plate 7 to slide. Steam is sprayed out through the steam plate 7 to preheat the heat exchange tube 4 in advance. The steam plate 7 can make the temperature of the heat exchange tube 4 rise gradually, avoiding rapid expansion or contraction caused by excessive temperature difference. When heat exchange begins, the surface temperature of the heat exchange tube 4 is already close to the working temperature, which helps to reduce thermal stress caused by rapid temperature change. The other end of the connecting hose 8 is connected to the external steam pump. At the same time, the connecting hose 8 is made of polyurethane material, which can quickly recover after being stretched by the steam plate 7.

[0021] The drive assembly includes a threaded rod 13 rotatably connected to the bottom wall of the preheating box 12. A slider 15 is threadedly connected to the threaded section of the threaded rod 13. A steam plate 7 is installed on the upper end face of the slider 15. Folding blades 11 are installed on both outer walls of the slider 15. The other ends of the folding blades 11 are in contact with the inner wall of the preheating box 12. The side walls of the folding blades 11 are in close contact with the inner wall of the preheating box 12. When flue gas enters the preheating box 12, it may adhere to the outer wall of the threaded rod 13 due to the impurities contained in the flue gas. The setting of the folding blades 11 can reduce the possibility of flue gas entering the preheating box 12, thereby avoiding the threaded rod 13 from rotating unevenly.

[0022] A limiting rod 14 is fixedly connected to the inner wall of the preheating box 12, and a slider 15 is slidably connected to the threaded section of the limiting rod 14. The preheating box 12 is connected to the cylinder 1 by multiple sets of screws 9, and the side plate 3 is connected to the cylinder 1 by multiple sets of screws 6. Sealing gaskets are installed at the contact surfaces of the side plate 3, the preheating box 12 and the cylinder 1. A servo motor 10 is fixedly connected to the side wall of the preheating box 12, and the output shaft end of the servo motor 10 is coaxially fixedly connected to the threaded rod 13. The preheating box 12 and the side plate 3 are designed to be detachable, so that they can be disassembled periodically to clean the heat exchange tube 4 and the threaded rod 13, reducing the heat transfer loss caused by impurities adhering to the outer wall of the heat exchange tube 4.

[0023] In this invention, the device is used as follows: the servo motor 10 drives the threaded rod 13 to rotate, and the rotation of the threaded rod 13 drives the slider 15 connected to its threaded section to move. The upper end face of the slider 15 is connected to the steam plate 7. During this process, the external steam pump delivers steam to the steam plate 7 through the connecting hose 8 and sprays steam out through the nozzle. After the steam is sprayed out, the steam preheats the heat exchange tube 4 through the steam plate 7, so that the surface temperature of the heat exchange tube 4 gradually rises, avoiding rapid expansion or contraction caused by excessive temperature difference, and reducing the thermal stress caused by rapid temperature change. As the slider 15 moves, the steam plate 7 slides inside the cylinder 1 to ensure that the steam is sprayed out evenly, achieving the preheating effect of the heat exchange tube 4.

[0024] The function of the folded blade 11 is to change the flow path of the flue gas, reduce the direct contact between impurities in the flue gas and the outer wall of the threaded rod 13, thereby preventing impurities from adhering to the threaded rod 13 and ensuring the smooth rotation of the threaded rod 13. By effectively isolating impurities through the folded blade 11, the threaded rod 13 can be rotated smoothly, avoiding friction and jamming caused by the accumulation of impurities.

[0025] Subsequently, the flue gas from the thermal power plant enters the preheating box 12 through the inlet and outlet pipes 2. The flue gas contains certain impurities, which may adhere to the inner surface of the cylinder 1 during the flow process. Since the preheating box 12 and the inner wall of the side plate 3 are equipped with sealing gaskets, it is ensured that the flue gas passes through well and there will be no leakage. After absorbing the heat from the flue gas, the heat exchange tube 4, which is heated by steam, gradually transfers the heat to the heat exchange system. The temperature of the heat exchange tube 4 gradually increases, so that the heat exchange tube 4 can quickly approach the working temperature in the subsequent heat exchange process, ensuring efficient heat exchange.

[0026] To ensure the long-term efficient operation of the system, the preheating box 12 and the side plate 3 are designed to be detachable. Users can periodically disassemble the preheating box 12 and the side plate 3 to clean the heat exchange tube 4 and the threaded rod 13.

[0027] It is worth mentioning that some companies use a small flow rate of flue gas for preheating. This device has a significant advantage in using steam preheating. Steam preheating can heat the heat exchange tube 4 more quickly and evenly. When using a small flow rate of flue gas for preheating, the relatively low temperature and limited flow rate of the flue gas can easily lead to uneven temperature distribution, which in turn affects the heat exchange efficiency. Therefore, the steam preheating solution not only improves the stability and adaptability of the system, but also optimizes energy utilization efficiency and has better long-term operating performance.

[0028] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A waste heat recovery system for a thermal power plant, comprising a cylinder (1), characterized in that, Both ends of the cylinder (1) are equipped with inlet and outlet pipes (2), which are connected to the inside of the cylinder (1). The side wall of the cylinder (1) is open, and a side plate (3) is installed there. Multiple sets of heat exchange tubes (4) are installed on the side wall of the side plate (3), and they are all S-shaped. Two sets of connecting pipes (5) are installed on the outer wall of the side plate (3), and they are connected to both ends of the multiple sets of heat exchange tubes (4). A steam plate (7) is slidably connected to the bottom of the cylinder (1). A connecting hose (8) is installed on the side wall of the cylinder (1). One end of the connecting hose (8) is connected to the inside of the steam plate (7). A preheating box (12) is installed at the lower end of the cylinder (1), and the upper end is open and extends to the bottom of the cylinder (1). A drive assembly for driving the steam plate (7) to slide is installed in the preheating box (12).

2. The waste heat recovery system for thermal power plants according to claim 1, characterized in that, The drive assembly includes a threaded rod (13) rotatably connected to the bottom wall of the preheating box (12), a slider (15) is threadedly connected to the threaded section of the threaded rod (13), and the steam plate (7) is installed on the upper end face of the slider (15).

3. The waste heat recovery system for thermal power plants according to claim 2, characterized in that, Folding blades (11) are installed on both outer walls of the slider (15). The other end of the folding blades (11) on both sides is in contact with the inner wall of the preheating box (12). The side wall of the folding blades (11) is in contact with the inner wall of the preheating box (12).

4. The waste heat recovery system for thermal power plants according to claim 3, characterized in that, The inner wall of the preheating box (12) is fixedly connected to a limiting rod (14), and the slider (15) is slidably connected to the threaded section of the limiting rod (14).

5. The waste heat recovery system for thermal power plants according to claim 4, characterized in that, The preheating box (12) is connected to the cylinder (1) by multiple sets of screws (9), and the side plate (3) is connected to the cylinder (1) by multiple sets of screws (6). Sealing gaskets are installed at the contact surfaces of the side plate (3) and the preheating box (12) with the cylinder (1).

6. The waste heat recovery system for thermal power plants according to claim 5, characterized in that, A servo motor (10) is fixedly connected to the side wall of the preheating box (12), and the end of the output shaft of the servo motor (10) is fixedly connected to the threaded rod (13) on the same axis.

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