Special-shaped tube pass structure of U-shaped tube heat exchanger

Abstract

The utility model discloses a special-shaped tube pass structure of a U-shaped tube heat exchanger, and belongs to the technical field of heat exchangers. The U-shaped tube heat exchanger overcomes the defects that in the prior art, when the flow speed of a tube pass medium is too high, the bent tube section of a U-shaped tube is seriously eroded, so that the service life of a tube bundle is influenced, and when the flow speed of the tube pass medium is too low, the bent tube section of the U-shaped tube is easy to block and difficult to clean. A main body structure of the heat exchanger comprises a tube box and a shell, an inner tube bundle is arranged in the tube box, an outer tube bundle is arranged in the shell, the inner tube bundle comprises an inner tube bundle tube plate and inner tube bundle heat exchange tubes installed on the inner tube bundle tube plate, and the outer tube bundle comprises an outer tube bundle tube plate arranged between the tube box and the shell and outer tube bundle heat exchange tubes installed on the outer tube bundle tube plate. And the inner tube bundle heat exchange tubes are inserted into the outer tube bundle heat exchange tubes. The heat exchanger is mainly used for heat exchange in high-temperature and high-pressure working conditions.

Description

Technical Field

[0001] The utility model belongs to the technical field of heat exchangers, and in particular relates to a special-shaped tube pass structure of a U-tube heat exchanger. Background Art

[0002] As a commonly used type of heat exchange equipment, the U-tube heat exchanger has the following structural features: 1. The tail end of the U-shaped heat exchange tube can float freely to release temperature difference stress, and can be used in high-temperature working conditions; 2. Its structure has only one tube sheet and a small number of equipment flanges, so the structure is simple, the leakage points are few, and materials are saved; 3. The tube bundle can be cored and cleaned, and the tube bundle can be replaced individually; 4. Among all the structural types of heat exchange equipment, the U-tube heat exchanger is the only type of equipment suitable for high-temperature and high-pressure working conditions, and is widely used.

[0003] However, compared with the above structural characteristics, the existing U-tube heat exchanger has the following disadvantages:

[0004] 1) The efficiency of the working operation is limited by the flow rate of the medium in the pipe. When the flow rate of the medium in the pipe is too high, it will cause serious erosion to the U-shaped pipe bend section, affecting the service life of the tube bundle; when the flow rate of the medium in the pipe is too low, if there are impurities, the U-shaped pipe bend section is easy to be blocked and difficult to clean;

[0005] 2) The partition plates in the pipe box will produce large bending stress under the pressure difference on both sides of the pipe. Under the impact of the high-velocity medium in the pipe, the partition plates will fail. In severe cases, the partition plates will be severely deformed, fall off, and tear the inner wall of the pipe box;

[0006] 3) The calculation of the equipment flange must take into account the support reaction force generated by the partition plate, which directly affects the sealing performance of the equipment flange.

[0007] For example, a Chinese utility model patent with authorization announcement number CN 206177089 U discloses a vertical U-tube heat exchanger, in which the shell-side medium before heat exchange enters the central tube, and then exchanges heat with the tube-side medium in the U-tube in the inner heat exchange channel and the outer heat exchange channel. The middle part of the tube sheet where the tube-side medium gathering chamber is located is the U-tube outlet part with a higher temperature, and the rest of the tube sheet surrounding the U-tube outlet part is the U-tube inlet part with a lower temperature. However, the disadvantage is that when the medium flow rate is too low, such as when there are some impurities, the U-tube bend section is easily blocked and difficult to clean, affecting the heat exchange efficiency. Utility Model Content

[0008] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a special-shaped tube pass structure of a U-tube heat exchanger.

[0009] In order to achieve the above purpose, the utility model is implemented by adopting the following technical solutions:

[0010] A special tube pass structure of a U-tube heat exchanger, comprising a tube box and a shell. An inner tube bundle is arranged in the tube box, and an outer tube bundle is arranged in the shell. The inner tube bundle includes an inner tube bundle tube sheet and inner tube bundle heat exchange tubes installed on the inner tube bundle tube sheet. The outer tube bundle includes an outer tube bundle tube sheet arranged between the tube box and the shell and outer tube bundle heat exchange tubes installed on the outer tube bundle tube sheet. The inner tube bundle heat exchange tubes are inserted into the outer tube bundle heat exchange tubes.

[0011] Preferably, the inner tube bundle tube sheet is arranged in the tube box, and the inner tube bundle tube sheet divides the tube box into a tube pass medium inlet cavity and a tube pass medium outlet cavity.

[0012] Preferably, a tube pass medium inlet is arranged at the tube pass medium inlet cavity, and a tube pass medium outlet is arranged at the tube pass medium outlet cavity.

[0013] Preferably, a shell pass medium inlet and a shell pass medium outlet are arranged on the shell.

[0014] Preferably, the inner tube bundle heat exchange tubes are straight tubes.

[0015] Preferably, the outer tube bundle heat exchange tubes are U-shaped tubes, and the inner tube bundle heat exchange tubes are inserted into the straight tube sections of the outer tube bundle heat exchange tubes for use.

[0016] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0017] 1. By arranging the inner tube bundle tube sheet in the tube box, and the inner tube bundle tube sheet divides the tube box into a tube pass medium inlet cavity and a tube pass medium outlet cavity, the present utility model effectively avoids the problems that the existing U-tube heat exchanger has deformation, detachment or even tearing of the inner wall of the tube box under the action of pressure difference and high-flow-rate medium due to the setting of the partition plate for dividing the passes. Since the present utility model does not need to consider the reaction force of the partition plate for dividing the passes, the sealing performance of the equipment flange is greatly improved;

[0018] 2. The present utility model effectively increases the flow rate of the tube pass medium, prolongs the service life of the tube bundle of the U-tube heat exchanger, lengthens the heat exchange time of the tube and shell pass media, and greatly improves the heat exchange efficiency of the heat exchanger;

[0019] 3. By inserting the inner tube bundle heat exchange tubes into the straight tube sections of the outer tube bundle heat exchange tubes for use, the flow and heat exchange time of the tube pass medium in the heat exchange tubes (inner tube bundle heat exchange tubes, outer tube bundle heat exchange tubes) is effectively lengthened, so that the tube and shell pass media can fully perform two heat exchanges in an effective space. Compared with the existing U-tube heat exchanger, the overall heat exchange efficiency of the heat exchanger can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of the present utility model.

[0021] In the figure: 1. Tube sheet; 2. Inner tube bundle; 3. Outer tube bundle; 4. Shell; 5. Tube-side medium inlet; 6. Tube-side medium outlet; 7. Shell-side medium inlet; 8. Shell-side medium outlet; 11. Tube-side medium inlet cavity; 12. Tube-side medium outlet cavity; 21. Inner tube bundle tube sheet; 22. Inner tube bundle heat exchange tubes; 31. Outer tube bundle tube sheet; 32. Outer tube bundle heat exchange tubes. Specific embodiments

[0022] The present utility model will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0023] Embodiment 1:

[0024] As Figure 1 shown, a special tube-side structure of a U-tube heat exchanger includes a tube sheet 1 and a shell 4. An inner tube bundle 2 is arranged in the tube sheet 1, and an outer tube bundle 3 is arranged in the shell 4. The inner tube bundle 2 includes an inner tube bundle tube sheet 21 and inner tube bundle heat exchange tubes 22 installed on the inner tube bundle tube sheet 21. The outer tube bundle 3 includes an outer tube bundle tube sheet 31 arranged between the tube sheet 1 and the shell 4 and outer tube bundle heat exchange tubes 32 installed on the outer tube bundle tube sheet 31. The inner tube bundle heat exchange tubes 22 are inserted into the outer tube bundle heat exchange tubes 32.

[0025] Embodiment 2:

[0026] A special tube-side structure of a U-tube heat exchanger is different from that of Embodiment 1 in that the inner tube bundle tube sheet 21 is arranged in the tube sheet 1, and the inner tube bundle tube sheet 21 divides the tube sheet 1 into a tube-side medium inlet cavity 11 and a tube-side medium outlet cavity 12.

[0027] Further, a tube-side medium inlet 5 is arranged at the tube-side medium inlet cavity 11, and a tube-side medium outlet 6 is arranged at the tube-side medium outlet cavity 12; a shell-side medium inlet 7 and a shell-side medium outlet 8 are arranged on the shell 4.

[0028] Further, the inner tube bundle heat exchange tubes 22 are straight tubes, and the outer tube bundle heat exchange tubes 32 are U-shaped tubes. The inner tube bundle heat exchange tubes 22 are inserted into the straight tube sections of the outer tube bundle heat exchange tubes 32 for use. By this method, the flow rate of the tube-side medium is effectively increased, and the heat exchange efficiency of the heat exchanger is greatly improved.

[0029] The working principle of the present utility model is:

[0030] The inner tube bundle tube sheet 21 is arranged in the tube box 1 to divide the tube box 1 into a tube-side medium inlet cavity 11 and a tube-side medium outlet cavity 12. A tube-side medium inlet 5 is arranged in the tube-side medium inlet cavity 11, and a tube-side medium outlet 6 is arranged in the tube-side medium outlet cavity 12. The medium flows into the tube-side medium inlet cavity 11 from the tube-side medium inlet 5, then flows into the inner tube bundle heat exchange tubes 22 and flows at a high speed inside the tubes. Since the inner tube bundle heat exchange tubes 22 are straight tubes and the outer tube bundle heat exchange tubes 32 are U-shaped tubes, and the inner tube bundle heat exchange tubes 22 are inserted into the outer tube bundle heat exchange tubes 32, therefore, after the medium flows out from the end of the inner tube bundle heat exchange tubes 22, it directly enters the U-shaped section part of the outer tube bundle heat exchange tubes 32. Subsequently, the two streams of medium flowing in the symmetrical direction in the U-shaped section part undergo convection, and the convection can effectively reduce the erosion of the high-flow-rate medium on the elbow section of the U-shaped tube and extend the service life of the tube bundle; after the convection, the flow direction of the medium changes, and it flows into the tube-side medium outlet cavity 12 in a reverse flow in the gap space between the outer tube bundle heat exchange tubes 32 and the inner tube bundle heat exchange tubes 22, and finally flows out of the heat exchanger from the tube-side medium outlet 6.

[0031] The shell-side medium flows into from the shell-side medium inlet 7 of the shell 4, and fully conducts two heat exchanges with the tube-side medium in the shell-side space between the inner and outer tube bundles. First, the heat exchange between the shell-side and the outer tube bundle 3; second, the heat exchange between the outer tube bundle 3 and the inner tube bundle 2. Finally, the shell-side medium flows out of the heat exchanger from the shell-side medium outlet 8 of the shell 4. The utility model effectively avoids both the problems that the partition plate is prone to failure and the support reaction force of the partition plate affects the sealing performance of the equipment flange after the tube box 1 is provided with a partition plate for dividing the process, and effectively improves the flow rate of the tube-side medium, thereby greatly improving the heat exchange efficiency of the heat exchanger.

Claims

1. A special-shaped tube structure of a U-tube heat exchanger, comprising a tube box (1) and a shell (4), characterized in that: An inner tube bundle (2) is arranged in the tube box (1), and an outer tube bundle (3) is arranged in the shell (4); the inner tube bundle (2) comprises an inner tube bundle tube sheet (21) and inner tube bundle heat exchange tubes (22) mounted on the inner tube bundle tube sheet (21); the outer tube bundle (3) comprises an outer tube bundle tube sheet (31) arranged between the tube box (1) and the shell (4) and outer tube bundle heat exchange tubes (32) mounted on the outer tube bundle tube sheet (31); the inner tube bundle heat exchange tubes (22) are inserted into the outer tube bundle heat exchange tubes (32).

2. The special-shaped tube structure of the U-tube heat exchanger according to claim 1 is characterized in that: The inner tube bundle tube sheet (21) is arranged in the tube box (1), and the inner tube bundle tube sheet (21) divides the tube box (1) into a tube side medium inlet cavity (11) and a tube side medium outlet cavity (12).

3. The special-shaped tube structure of the U-tube heat exchanger according to claim 2 is characterized in that: The tube-side medium inlet cavity (11) is provided with a tube-side medium inlet (5), and the tube-side medium outlet cavity (12) is provided with a tube-side medium outlet (6).

4. The special-shaped tube structure of the U-tube heat exchanger according to claim 1 is characterized in that: The shell (4) is provided with a shell-side medium inlet (7) and a shell-side medium outlet (8).

5. The special-shaped tube structure of the U-tube heat exchanger according to any one of claims 1 to 4, characterized in that: The inner tube bundle heat exchange tube (22) is a straight tube.

6. The special-shaped tube structure of the U-tube heat exchanger according to claim 5, characterized in that: The outer tube bundle heat exchange tube (32) is a U-shaped tube.

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