Horizontal integrated hairpin type feed water heater for power plant

Abstract

The invention relates to a horizontal integrated hairpin type feed water heater for a power plant. The horizontal integrated hairpin type feed water heater comprises a left pipe box, a right pipe box, two pipe plates, a group of feed water inlet and outlet pipes, a U-shaped pipe bundle, two straight-section shells, a hairpin bend connected with the two straight-section shells, a steam inlet, a drain outlet and other parts. The device is particularly suitable for heaters with small pipe side feed water flow and higher temperature rise; the high-temperature feed water and the low-temperature feed water are distributed in the two relatively independent tube boxes, so that the temperature difference stress of a tube plate and a tube box sealing head is avoided; the overheating section, the condensation section and the subcooling section are integrated in one device, so that the occupied area of the device and the number of connecting pipelines can be reduced; deformation stress caused by thermal displacement difference of two sections of barrel bodies of the equipment can be greatly reduced through four-support configuration; the overall height of the equipment can be reduced through horizontal arrangement, and overhaul and maintenance are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchanger design for power plants, and in particular to a horizontal integrated hairpin type feedwater heater for power plants. Background Art

[0002] The feedwater heater for power plants is divided into two chambers, the cold side and the hot side. The two media are distributed in the two chambers respectively, and heat exchange is carried out through the heat exchange tube bundle. The cold side is the feedwater supplied to the steam generator, which flows in the heat exchange tube bundle, and the hot side is the steam, which flows outside the heat exchange tube bundle. The feedwater heater can integrate three heat exchange areas, namely the superheating section, the condensation section and the cooling section. The functions of each section are as follows: the superheating section, the steam with superheat enters the heater in this area for heat transfer, and when it flows out of this area, it is close to the saturation temperature, and at the same time, the sensible heat of the superheated steam is transferred to the feedwater; the condensation section, the saturated steam on the shell side gradually condenses into condensed water, and the shell side temperature is constant in the entire area, and the latent heat of steam condensation is transferred to the feedwater in this area. The condensation section is the main heat transfer section of the feedwater heater. Its heat transfer and heat transfer area occupy most of the equipment and is the main body of the feedwater heater; the cooling section, the condensed water on the shell side enters and exits this area for heat transfer, and the temperature will be lower than the saturation temperature when it flows out of the shell side, and at the same time, the heat is transferred to the feedwater on the tube side.

[0003] At present, the feedwater heaters used in power plants are mainly U-shaped tube heaters, such as Figure 1 As shown, it includes tube side components and shell side components. The tube side components are composed of a tube sheet 10, a hemispherical water chamber head 9, a water chamber head water supply outlet 91, a water chamber head water supply inlet 92 and a set of U-shaped tube bundles 8; the shell side components are composed of a set of cylinders, a steam inlet 61 and a drain outlet 51.

[0004] When the tube-side water supply flow of the heater is small but the temperature rise is high (above 100°C), because the design pressure on the tube side is generally high (over 20MPa), the thickness of the hemispherical water chamber head 9 and the tube sheet 10 are relatively large. Therefore, when high and low temperature water supplies are distributed in the same hemispherical water chamber, the high and low temperature water supplies simultaneously contact the tube sheet and water chamber head with larger thickness specifications, which will inevitably cause temperature difference stress, which is not conducive to the reliable operation of the water supply heater. Summary of the invention

[0005] In order to solve the technical problem that when high and low temperature feed water are distributed in the same hemispherical water chamber, the high and low temperature feed water simultaneously contact the tube sheet and water chamber head with larger thickness specifications, causing temperature difference stress, thus affecting the operating reliability of the feed water heater, a horizontal integrated hairpin feed water heater for power plants is proposed.

[0006] The technical solution of the present invention is: a horizontal integrated hairpin feedwater heater for a power plant, comprising an inlet pipe box, the inlet pipe box is connected to an inlet tube sheet, a side of the inlet tube sheet away from the inlet pipe box is connected to a first shell, an end of the first shell away from the inlet tube sheet is connected to a hairpin, an end of the hairpin away from the first shell is connected to a second shell, an end of the second shell away from the hairpin is connected to an outlet tube sheet, and a side of the outlet tube sheet away from the second shell is connected to an outlet pipe box;

[0007] A U-shaped tube bundle is arranged inside the first shell, the second shell and the hairpin, one end of the U-shaped tube bundle is connected to the inlet tube sheet, and the end of the U-shaped tube bundle away from the inlet tube sheet is connected to the outlet tube sheet.

[0008] Preferably, the inlet pipe box and the outlet pipe box are cylindrical bodies, a water supply inlet is provided at the bottom of the inlet pipe box, and a water supply outlet is provided at the top of the outlet pipe box.

[0009] Preferably, the first shell and the second shell are in the shape of straight hollow cylinders, and the hairpin bend is in the shape of a semicircular hollow cylinder.

[0010] Preferably, the U-shaped tube bundle is symmetrically and evenly distributed in the first shell, the second shell and the hairpin bend.

[0011] Preferably, the first shell is provided with a drain outlet, and the second shell is provided with a steam inlet.

[0012] Preferably, four supports are arranged at the lower part of the feed water heater. To ensure that the two sections of the cylinder body can freely expand thermally in two directions in the horizontal plane, one of the four supports is a fixed support, the diagonal direction of the fixed support is a bidirectional sliding support, and the remaining two supports are unidirectional sliding supports.

[0013] The beneficial effects of the present invention are as follows: the present invention is a horizontal integrated hairpin feed water heater for power plants, in which high-temperature feed water and low-temperature feed water are distributed in two independent left and right pipe box chambers respectively, thereby avoiding the problem of temperature difference stress in the same pipe box cavity in traditional U-shaped tube high-pressure heaters, improving the reliability of equipment operation, allowing the high-pressure heater to achieve a higher feed water temperature rise, thereby reducing the number of high-pressure heaters in the same unit, and playing a role in saving costs; the superheating section, condensation section and cooling section are integrated in one device, which can realize the functional integration of the equipment, reduce the equipment footprint and the number of connecting pipes; the four-support configuration can greatly reduce the deformation stress caused by the thermal displacement difference of the two sections of the equipment barrel, and can further improve the equipment operation reliability; the horizontal arrangement can reduce the overall height of the equipment, which is convenient for inspection and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of a U-tube feedwater heater in the prior art;

[0015] Figure 2It is a top view of the structure of the horizontal integrated hairpin type water heater of the present invention;

[0016] Figure 3 It is a structural front view of the horizontal integrated hairpin type water heater of the present invention.

[0017] In the figure, the component names corresponding to the reference numerals are as follows:

[0018] 1. Inlet pipe box; 11. Water supply inlet; 2. Inlet tube sheet; 3. Outlet pipe box; 31. Water supply outlet; 4. Outlet tube sheet; 5. First shell; 51. Drain outlet; 52. First support; 53. Second support; 6. Second shell; 61. Steam inlet; 62. Third support; 63. Fourth support; 7. Hairpin; 8. U-shaped tube bundle; 9. Hemispherical water chamber head; 91. Water chamber head water supply outlet; 92. Water chamber head water supply inlet; 10. Tube sheet. DETAILED DESCRIPTION

[0019] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0020] refer to Figure 2 , 3 As shown, the present invention provides a horizontal integrated hairpin feedwater heater for a power plant, comprising an inlet pipe box 1, one end face of the inlet pipe box 1 is connected to an inlet tube sheet 2, a side of the inlet tube sheet 2 away from the inlet pipe box 1 is connected to a first shell 5, an end of the first shell 5 away from the inlet tube sheet 2 is connected to a hairpin bend 7, an end of the hairpin bend 7 away from the first shell 5 is connected to a second shell 6, an end of the second shell 6 away from the hairpin bend 7 is connected to an outlet tube sheet 4, and a side of the outlet tube sheet 4 away from the second shell 6 is connected to an end face of the outlet pipe box 3;

[0021] A U-shaped tube bundle 8 is provided inside the first shell 5, the second shell 6 and the hairpin bend 7, one end of the U-shaped tube bundle 8 is connected to the inlet tube sheet 2, and the end of the U-shaped tube bundle 8 away from the inlet tube sheet 2 is connected to the outlet tube sheet 4; a superheating section, a condensing section and a cooling section are provided inside the heater to realize the heat release process of the shell side steam from superheated steam, saturated steam, saturated water and subcooled water, so as to heat the feed water flowing through the U-shaped tube bundle 8.

[0022] Specifically, the inlet pipe box 1 and the outlet pipe box 3 are cylindrical bodies, the bottom of the inlet pipe box 1 is provided with a water supply inlet 11, and the top of the outlet pipe box 3 is provided with a water supply outlet 31;

[0023] Specifically, the first shell 5 and the second shell 6 are straight hollow cylinders, and the hairpin 7 is a U-shaped hollow cylinder;

[0024] Specifically, the U-shaped tube bundle 8 is symmetrically and evenly distributed in the first shell 5, the second shell 6 and the hairpin 7;

[0025] The central axis of the water supply inlet 11 and the central axis of the first shell 5 are located in the same vertical plane; the central axis of the water supply outlet 31 and the central axis of the second shell 6 are located in the same vertical plane;

[0026] Specifically, a drain outlet 51 is provided at the top of the first shell 5, and the drain outlet 51 is located near the inlet tube sheet 2 of the first shell 5, and the central axis of the drain outlet 51 and the central axis of the first shell 5 are located in the same vertical plane; a steam inlet 61 is provided at the top of the second shell 6, and the steam inlet 61 is located near the outlet tube sheet 4 of the second shell 6, and the central axis of the steam inlet 61 and the central axis of the second shell 6 are located in the same vertical plane; in this example, the drain outlet 51 and the steam inlet 61 are both cylindrical pipes;

[0027] Specifically, a first support 52 and a second support 53 are provided at the bottom of the first shell 5. The first support 52 is located near the inlet tube sheet 2, and the second support 53 is located near the hairpin bend 7.

[0028] The bottom of the second shell 6 is provided with a third support 62 and a fourth support 63, the third support 62 is located near the outlet tube sheet 4, and the fourth support 63 is located near the hairpin bend 7;

[0029] Specifically, the first support 52 and the fourth support 63 are one-way sliding supports, the sliding direction of the first support 52 is the same as the vertical direction of the axis of the first shell 5, and the sliding direction of the fourth support 63 is the same as the axis direction of the second shell 6;

[0030] The third support 62 is a fixed support, and the second support 53 is a bidirectional sliding support. The second support 53 can slide along the axis of the first shell 5 and in a direction perpendicular to the axis;

[0031] In other embodiments, the support position is not uniquely fixed, and it is necessary to ensure that the fixed support and the bidirectional sliding support are in the diagonal direction, and the unidirectional sliding support is set at the remaining positions.

[0032] The horizontal integrated hairpin feedwater heater used in power plants has the following characteristics: high-temperature feedwater and low-temperature feedwater are distributed in two independent pipe box chambers on the left and right, respectively, avoiding the problem of temperature difference stress in the same pipe box cavity in traditional U-shaped tube high-pressure heaters, improving the reliability of equipment operation, and allowing the high-pressure heater to achieve a higher feedwater temperature rise, thereby reducing the number of high-pressure heaters in the same unit, playing a role in saving costs; the superheating section, condensation section and cooling section are integrated in one device, which can realize the functional integration of the equipment, reduce the equipment footprint and the number of connecting pipes; the four-support configuration can greatly reduce the deformation stress caused by the thermal displacement difference of the two sections of the equipment barrel, which can further improve the reliability of equipment operation; the horizontal layout can reduce the overall height of the equipment, which is convenient for inspection and maintenance.

[0033] It should be noted that the orientations or positional relationships indicated by the above-mentioned terms "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are 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. The terms "first", "second", etc. are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. "Multiple" means two or more. "Installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection.

[0034] The above is only a preferred embodiment of the present invention, and is not any formal or substantial limitation of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the present invention, and these improvements and supplements should also be regarded as the protection scope of the present invention. Any technician familiar with this profession, without departing from the spirit and scope of the present invention, can make some changes, modifications and equivalent changes made by using the technical content disclosed above, which are equivalent embodiments of the present invention; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A horizontal integrated hairpin feedwater heater for a power plant, characterized in that: The invention comprises an inlet pipe box (1), the inlet pipe box (1) is connected to an inlet tube sheet (2), a side of the inlet tube sheet (2) away from the inlet pipe box (1) is connected to a first shell (5), an end of the first shell (5) away from the inlet tube sheet (2) is connected to a hairpin bend (7), an end of the hairpin bend (7) away from the first shell (5) is connected to a second shell (6), an end of the second shell (6) away from the hairpin bend (7) is connected to an outlet tube sheet (4), and a side of the outlet tube sheet (4) away from the second shell (6) is connected to an outlet pipe box (3); A U-shaped tube bundle (8) is provided inside the first shell (5), the second shell (6) and the hairpin bend (7); one end of the U-shaped tube bundle (8) is connected to the inlet tube sheet (2), and the end of the U-shaped tube bundle (8) away from the inlet tube sheet (2) is connected to the outlet tube sheet (4).

2. The horizontal integrated hairpin feedwater heater for power plants according to claim 1, characterized in that: The inlet pipe box (1) and the outlet pipe box (3) are cylindrical bodies. The bottom of the inlet pipe box (1) is provided with a water supply inlet (11), and the top of the outlet pipe box (3) is provided with a water supply outlet (31).

3. The horizontal integrated hairpin feedwater heater for power plants according to claim 1, characterized in that: The first shell (5) and the second shell (6) are in the shape of straight hollow cylinders, and the hairpin bend (7) is in the shape of a semicircular hollow cylinder.

4. The horizontal integrated hairpin feedwater heater for power plants according to claim 3, characterized in that: The U-shaped tube bundle (8) is symmetrically and evenly distributed in the first shell (5), the second shell (6) and the hairpin bend (7).

5. The horizontal integrated hairpin feedwater heater for power plants according to claim 3, characterized in that: The first shell (5) is provided with a drain outlet (51), and the second shell (6) is provided with a steam inlet (61).

6. The horizontal integrated hairpin feedwater heater for power plants according to claim 3, characterized in that: Four supports are arranged at the lower part of the feedwater heater. To ensure that the two sections of the barrel can freely expand thermally in two directions in the horizontal plane, one of the four supports is a fixed support, the diagonal direction of the fixed support is a bidirectional sliding support, and the remaining two supports are unidirectional sliding supports.

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