A high pressure and high temperature difference pure countercurrent multi-fluid heat exchanger

Abstract

A high-pressure, high-temperature difference pure countercurrent multi-fluid heat exchanger comprises a horizontally placed U-shaped tube bundle, which is installed in an outer shell, wherein the heat exchange tube in the center of the upper section of the U-shaped tube bundle is sealed and connected to the upper inner tube box through the tube hole in the middle of the upper tube plate, and the remaining heat exchange tubes are sealed and connected to the upper outer tube box through the tube holes on the outer periphery of the upper tube plate, one end of the cold flow II outlet is connected to the upper inner tube box, and the other end is sealed and extended out of the upper outer tube box; the heat exchange tube in the center of the lower section of the U-shaped tube bundle is sealed and connected to the lower inner tube box through the tube hole in the middle of the lower tube plate, and the remaining heat exchange tubes are sealed and connected to the lower outer tube box through the tube holes on the outer periphery of the lower tube plate, one end of the cold flow II inlet is connected to the lower inner tube box, and the other end is sealed and extended out of the lower outer tube box; a shell-side inlet is provided at the upper part of the outer shell near the upper tube plate; and a shell-side outlet is provided at the lower part of the outer shell near the lower tube plate. The invention has a simple and compact structure and occupies a small area, and can realize multi-fluid pure countercurrent heat transfer with high pressure for both cold and hot flows and a high temperature difference.

Description

Technical Field

[0001] The invention belongs to the technical field of heat exchangers and relates to a high-pressure, high-temperature-difference, pure countercurrent multi-fluid heat exchanger. Background Art

[0002] At present, the heat exchangers used in multi-fluid heat exchangers include: plate-fin heat exchangers, wound-tube heat exchangers and shell-and-tube heat exchangers. Plate-fin heat exchangers have high heat transfer efficiency, followed by wound-tube heat exchangers, and ordinary shell-and-tube heat exchangers have the lowest. When the heat transfer fluids are all medium and low pressure media, plate-fin heat exchangers are given priority. When one heat transfer fluid is high pressure and the others are medium and low pressure, since plate-fin heat exchangers can only be used for medium and low pressure conditions, they are not suitable for this condition; wound-tube heat exchangers can be used for medium and low pressure conditions in the tube side and high pressure conditions in the shell side, so wound-tube heat exchangers are given priority. When two or more fluids in the heat exchange medium are high pressure media, the wound-tube heat exchanger will no longer be applicable, and only shell-and-tube heat exchangers can be used at this time.

[0003] At present, high-pressure multi-fluid shell and tube heat exchangers include conventional U-tube heat exchangers and fixed tube sheet heat exchangers. When a conventional U-tube heat exchanger is used, the heat exchanger tube box partition adopts a flat structure. Due to the high pressure conditions of the tube side medium, the thickness of the tube box partition is very thick, which makes the welding and sealing of the tube box partition very difficult, and even impossible to design and process. When the temperature difference stress load of the tube and shell is superimposed, the tube sheet itself and the connection between the tube sheet and the tube box and the shell are extremely easy to fail. When a fixed tube sheet heat exchanger structure is used, the equipment shell diameter is large, the efficiency is low, and the investment is high. When the temperature difference stress load of the tube and shell is attached, the fixed tube sheet heat exchanger will not be used because the expansion joint cannot be set under high pressure conditions. Summary of the invention

[0004] The present invention provides a high-pressure, high-temperature difference, pure countercurrent multi-fluid heat exchanger, which provides a feasible solution for the current high-pressure multi-fluid heat exchanger and can achieve high-pressure, high-temperature difference, pure countercurrent heat transfer of the fluid.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A high-pressure, high-temperature-difference pure countercurrent multi-fluid heat exchanger comprises a horizontally placed U-shaped tube bundle, which is installed in an outer shell. The heat exchange tube in the center of the upper section of the U-shaped tube bundle is sealed and connected to the upper inner tube box through the tube hole in the middle of the upper tube plate, while the remaining heat exchange tubes are sealed and connected to the upper outer tube box through the tube holes on the outer periphery of the upper tube plate. One end of the cold flow II outlet is connected to the upper inner tube box, and the other end is sealed and extended out of the upper outer tube box. The upper part of the upper outer tube box is provided with a cold flow I outlet; the heat exchange tube in the center of the lower section of the U-shaped tube bundle is sealed and connected to the lower inner tube box through the tube hole in the middle of the lower tube plate, while the remaining heat exchange tubes are sealed and connected to the lower outer tube box through the tube holes on the outer periphery of the lower tube plate, one end of the cold flow II inlet is connected to the lower inner tube box, and the other end is sealed and extended out of the lower outer tube box; the lower part of the lower outer tube box is provided with a cold flow I inlet; the upper part of the outer shell near the upper tube plate is provided with a shell-side inlet; the lower part of the outer shell near the lower tube plate is provided with a shell-side outlet.

[0007] A feed distribution plate is provided between the lower outer tube box and the lower inner tube box.

[0008] The upper outer tube box, the upper inner tube box, the lower outer tube box and the lower inner tube box are all composed of a pressure-resistant cylinder and a pressure-resistant spherical shell.

[0009] The outer shell is formed by sealingly connecting an upper shell section, a middle shell section and a lower shell section to form a U-shaped shell.

[0010] The invention has a simple and compact structure and occupies a small area, and can realize pure countercurrent heat transfer of multiple fluids in which both the cold and hot flows are at high pressure and have a high temperature difference. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the present invention;

[0012] Figure 2 for Figure 1 Side view of

[0013] Figure 3 is a cross-sectional schematic diagram of the tube sheet of the present invention;

[0014] In the figure: cold flow II inlet 1, lower outer tube box 2, cold flow I inlet 3, lower inner tube box 4, hot flow outlet 5, support bracket 6, U-shaped tube bundle 7, lower shell 8, feed distributor 9, lower special-shaped tube sheet 10, cold flow II outlet 11, upper outer tube box 12, cold flow I outlet 13, upper inner tube box 14, upper special-shaped tube sheet 15, hot flow inlet 16, upper shell 17, middle shell 18. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with the accompanying drawings.

[0016] Reference Figure 1 , 23. A high-pressure, high-temperature difference pure countercurrent multi-fluid heat exchanger, comprising a horizontally placed U-shaped tube bundle, the U-shaped tube bundle being installed in a shell, the heat exchange tube in the center of the upper section of the U-shaped tube bundle 7 being sealed and connected to the upper inner tube box 14 through the tube hole in the middle of the upper tube sheet 15, and the remaining heat exchange tubes being sealed and connected to the upper outer tube box 12 through the tube holes on the outer periphery of the upper tube sheet 15, one end of the cold flow II outlet 11 being connected to the upper inner tube box 14, and the other end being sealed and extending out of the upper outer tube box 12, the upper portion of the upper outer tube box 12 being provided with a cold flow I outlet outlet 13; the heat exchange tube in the center of the lower section of the U-shaped tube bundle 7 is sealed and connected to the lower inner tube box 4 through the tube hole in the middle of the lower tube plate 10, and the remaining heat exchange tubes are sealed and connected to the lower outer tube box 2 through the tube holes on the periphery of the lower tube plate 10; one end of the cold flow II inlet 1 is connected to the lower inner tube box 4, and the other end is sealed and extends out of the lower outer tube box 2; a cold flow I inlet 3 is arranged at the lower part of the lower outer tube box 2; a hot flow inlet 16 is arranged at the upper part of the shell near the upper tube plate 15; a hot flow outlet 5 is arranged at the lower part of the shell near the lower tube plate 10.

[0017] The upper tube sheet annular area between the upper outer tube box 12 and the upper inner tube box 14 and the lower tube sheet annular area between the lower outer tube box 2 and the lower inner tube box 4 are connected by a set of U-shaped heat exchange tubes; the circular area of ​​the upper tube sheet corresponding to the upper inner tube box 14 and the circular area of ​​the lower tube sheet corresponding to the lower inner tube box 4 are connected by another set of U-shaped heat exchange tubes. The cold flow II goes through the inner tube box, the cold flow I goes through the outer tube box, and the hot flow goes through the shell, thus ensuring that the cold and hot fluids realize multi-fluid pure countercurrent heat transfer through the U-shaped tube bundle.

[0018] The upper and lower tube sheets provided in the present invention can avoid the influence of the temperature difference stress between the inlet and outlet of the single-side fluid, and the U-shaped tube bundle also effectively absorbs the temperature difference stress between the tube and shell fluids, so that the present invention can adapt to greater temperature difference stress.

[0019] A feed distribution plate 9 is provided between the lower outer tube box 2 and the lower inner tube box 4; the annular section between the lower outer tube box 2 and the lower inner tube box 4 is the inlet tube box section of the cold flow I. Due to the influence of the inner tube box in this section, the cold flow I cannot be evenly distributed to the inlet section of the tube sheet heat exchange tube. The present invention arranges a feed distribution plate in this section to make the cold flow I evenly distributed in the inlet section of the tube sheet.

[0020] The upper outer tube box 12, the upper inner tube box 14, the lower outer tube box 2 and the lower inner tube box 4 are all composed of a pressure-resistant cylinder and a pressure-resistant spherical shell. The upper shell pressure shell and the lower shell pressure shell are respectively welded to the corresponding upper tube sheet and lower tube sheet; the advantages of the good pressure resistance of the rotary shell are utilized to ensure the high pressure resistance and sealing performance of the present invention.

[0021] The shell is sealed and connected to form a U-shaped shell by the upper shell 17, the middle shell 18, and the lower shell 8. The large shell of a conventional high-pressure container is changed into two small shells, which has high heat transfer efficiency, low equipment weight, and low investment.

[0022] The shell is supported by a support bracket 6, and the upper and lower support brackets 6 in the U-shaped shell groove are connected as a whole.

[0023] Working process of the present invention:

[0024] There are three kinds of fluids, cold flow I and cold flow II, which exchange heat with hot flow. Among them, cold flow I enters the annular closed space formed by the lower outer tube box 2 and the lower inner tube box 4 through the cold flow I inlet 3, and enters a group of U-shaped tube groups connected to the lower tube sheet 10 after being evenly distributed by the feed distributor 9. After the U-shaped tube group and the hot fluid outside the tube are counter-heated, it enters the annular closed space formed by the upper outer tube box 12 and the upper inner tube box 14 connected to the upper tube sheet 15, and flows out from the cold flow I outlet 13; cold flow II enters the lower inner tube box 4 through the cold flow II inlet 1, and then enters another group of U-shaped tube groups connected to the lower tube sheet 10. After the U-shaped tube group and the hot fluid outside the tube are counter-heated, it enters the upper inner tube box 14 connected to the upper tube sheet 15, and flows out from the cold flow II outlet 11. The hot flow flows into the upper shell 17 from the hot flow inlet 16 , conducts countercurrent heat transfer with the cold flow I and the cold flow II outside the U-shaped tube bundle 7 , and flows out through the hot flow outlet 5 on the lower shell 8 .

Claims

1. A high pressure and high temperature difference pure countercurrent multi-fluid heat exchanger, comprising a horizontally placed U-shaped tube bundle, the U-shaped tube bundle being installed in a shell, characterized in that: The heat exchange tube in the center of the upper section of the U-shaped tube bundle (7) is sealed and connected to the upper inner tube box (14) through the tube hole in the middle of the upper tube plate (15), while the remaining heat exchange tubes are sealed and connected to the upper outer tube box (12) through the tube holes on the outer periphery of the upper tube plate (15); one end of the cold flow II outlet (11) is connected to the upper inner tube box (14) and the other end is sealed and extends out of the upper outer tube box (12); a cold flow I outlet (13) is provided on the upper part of the upper outer tube box (12); the heat exchange tube in the center of the lower section of the U-shaped tube bundle (7) is sealed and connected to the upper inner tube box (14) through the lower tube plate The middle tube hole of the heat exchange tube (10) is sealed and connected to the lower inner tube box (4), while the remaining heat exchange tubes are sealed and connected to the lower outer tube box (2) through the outer tube holes of the lower tube plate (10). One end of the cold flow II inlet (1) is connected to the lower inner tube box (4), and the other end is sealed and extends out of the lower outer tube box (2). A cold flow I inlet (3) is arranged at the lower part of the lower outer tube box (2). A shell-side inlet (16) is arranged at the upper part of the shell near the upper tube plate (15); and a shell-side outlet (5) is arranged at the lower part of the shell near the lower tube plate (10).

2. A high pressure and high temperature difference pure countercurrent multi-fluid heat exchanger according to claim 1, characterized in that: A feed distribution plate (9) is provided between the lower outer tube box (2) and the lower inner tube box (4).

3. A high pressure and high temperature difference pure countercurrent multi-fluid heat exchanger according to claim 1, characterized in that: The upper outer tube box (12), the upper inner tube box (14), the lower outer tube box (2) and the lower inner tube box (4) are all composed of a pressure-resistant cylinder and a pressure-resistant spherical shell.

4. A high pressure and high temperature difference pure countercurrent multi-fluid heat exchanger according to any one of claims 1 to 3, characterized in that: The outer shell is formed by sealingly connecting an upper shell (17), a middle shell (18), and a lower shell (8) to form a U-shaped shell.

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