A gas-liquid shell and tube heat exchanger for heating liquid medicine

Abstract

The present invention provides a gas-liquid shell and tube heat exchanger, wherein the shell-side inlet pipe is arranged at the upper part of the shell, and a plurality of horizontal baffle groups are arranged in the shell, and the baffle groups include a circular baffle located at the center of the shell and an annular baffle located around the shell; the shell-side inlet pipe is arranged at the upper part of the shell, and a plurality of horizontal baffle groups are arranged in the shell, and the baffle groups include a circular baffle located at the center of the shell and an annular baffle located around the shell; along the upward flow direction of the gas, the area ratio of the circular baffles in the baffle group to the annular baffles first gradually decreases, and then gradually increases. The present invention can improve the local heat exchange coefficient and further enhance heat transfer by changing the change in the area of ​​the circular baffles and the annular baffles.

Description

Technical Field

[0001] The invention relates to a shell and tube heat exchanger, in particular to a shell and tube heat exchanger for gas-liquid heat exchange. Background Art

[0002] Shell and tube heat exchangers are widely used in industries such as chemical, petroleum, refrigeration, nuclear energy and power. Due to the global energy crisis, in order to reduce energy consumption, the demand for heat exchangers in industrial production is increasing, and the quality requirements for heat exchangers are also getting higher and higher. In recent decades, although compact heat exchangers (plate, plate-fin, press-welded plate heat exchangers, etc.), heat pipe heat exchangers, direct contact heat exchangers, etc. have developed rapidly, shell and tube heat exchangers still dominate production and usage due to their high reliability and wide adaptability. According to relevant statistics, the use of shell and tube heat exchangers in industrial devices still accounts for about 70% of all heat exchangers.

[0003] Traditional bow-shaped baffles have many problems: (1) Bow-shaped baffles cause the fluid to vertically impact the shell wall, resulting in a large pressure drop along the path and increasing the load on the power equipment; (2) High-velocity fluid sweeps across the heat exchange tube bundle, inducing vibration of the heat exchange tube and shortening the life of the heat exchanger; (3) Flow stagnation dead zones are generated at the junction of the baffle and the shell wall, reducing the heat transfer efficiency and easily causing scaling. In response to these problems, some new shell and tube heat exchangers have been developed in recent years, such as shell and tube heat exchangers with a combination of annular and circular baffles.

[0004] However, the traditional baffle heat exchanger also has some shortcomings, such as large flow resistance, a large number of flow dead zones, low heat transfer efficiency, etc. Therefore, under the new energy conservation and emission reduction situation, its development is greatly restricted. Therefore, in view of these shortcomings, a baffle and shell and tube heat exchanger with simple structure and mature technology is developed to effectively improve its heat exchange area and heat exchange efficiency, which is of great significance to industrial production and energy conservation and emission reduction. Summary of the invention

[0005] In order to overcome the defects and shortcomings in the prior art, the present invention provides a shell and tube heat exchanger with a new layout of baffles, which can improve the convective heat transfer coefficient of the shell side of the heat exchanger, thereby effectively improving the heat transfer efficiency.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] A gas-liquid shell and tube heat exchanger, which comprises a shell, heat exchange tubes, a shell-side inlet pipe and a shell-side outlet pipe; the shell-side inlet pipe and the shell-side outlet pipe are respectively located at the upper end and the lower end of the heat exchanger; the heat exchange tubes are arranged in the shell, and the heat exchange tubes are fixedly connected to the upper tube plate and the lower tube plate; the liquid enters from the shell-side inlet pipe, exchanges heat through the heat exchange tubes, and goes out from the shell-side outlet pipe; the gas enters the heat exchange tubes from the lower head of the heat exchange tubes and flows out from the upper head of the heat exchange tubes; it is characterized in that the shell-side inlet pipe is arranged at the upper part of the shell, and a plurality of horizontal baffle groups are arranged in the shell, the baffle group comprises a circular baffle located at the center of the shell and an annular baffle located around the shell; along the upward flow direction of the gas, the ratio of the area of ​​the circular baffles in the baffle group to the area of ​​the annular baffles first gradually decreases, and then gradually increases.

[0008] As an improvement, at the center position in the vertical direction of the shell, the ratio of the area of ​​the circular baffle to the area of ​​the annular baffle reaches the maximum.

[0009] As an improvement, along the upward flow direction of the gas, the ratio of the area of ​​the circular baffles in the baffle group to the area of ​​the annular baffles gradually decreases to a larger and larger extent; the ratio of the area of ​​the circular baffles in the baffle group to the area of ​​the annular baffles gradually increases to a smaller and smaller extent.

[0010] As an improvement, the sum of the projected areas of the circular baffles and the annular baffles of the baffle group on the shell cross section is 110-120% of the shell cross section area.

[0011] As an improvement, the ratio of the area of ​​the circular baffles of the baffle group to the area of ​​the annular baffles is 0.8-1.2.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] 1) In the present invention, the area ratio of the circular baffles to the annular baffles in the baffle group changes along the upward flow direction of the gas, so that the fluid in the shell gradually moves closer to the center in the middle, so that the heat exchange tubes around the shell at the center of the fluid are strengthened, and then the heat exchange tubes at the center of the shell at the upper and lower ends are strengthened, and the heat exchange at the bottom inlet center and the heat exchange at the top outlet are strengthened, which changes the previous single heat exchange mode from top to bottom, strengthens the heat exchange efficiency at different positions, makes the heat exchange uniform on the whole, and further achieves the purpose of strengthening heat transfer.

[0014] 2) By changing the spacing between the baffles, the heat exchange area between the tube-side fluid and the shell-side fluid in the baffles also changes. Therefore, the uneven heat exchange amount is compensated by the change in area, thereby further improving the heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a shell and tube heat exchanger of the prior art;

[0016] Figure 2 It is a schematic diagram of the heat exchange tube structure of the shell and tube heat exchanger of the horizontal baffle group provided in the present invention;

[0017] Figure 3 1. is a top view schematic diagram of the annular baffle plate provided in the present invention;

[0018] Figure 4 It is a top view schematic diagram of the circular baffle plate provided in the present invention. DETAILED DESCRIPTION

[0019] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0020] In this article, unless otherwise specified, “ / ” represents division, and “×” and “*” represent multiplication.

[0021] It should be noted that, unless otherwise specified, the gas here is an insoluble or poorly soluble gas, that is, the gas will not dissolve in the liquid during the heat exchange process.

[0022] A shell and tube heat exchanger for gas-liquid heat exchange, such as Figure 1 As shown, the shell and tube heat exchanger is arranged in a vertical direction, and includes a shell 1, a heat exchange tube 8, a shell-side inlet pipe 2 and a shell-side outlet pipe 3; the shell-side inlet pipe 2 and the shell-side outlet pipe 3 are respectively located at the sides of the upper end and the lower end of the shell 1; the heat exchange tube 8 is arranged in the shell 1, and the heat exchange tube is fixedly connected to the upper tube sheet 6 and the lower tube sheet 7; the front end of the upper tube sheet 6 is connected to the upper head 4, and the rear end of the lower tube sheet 7 is connected to the lower head 5; the tube-side outlet pipe 10 is arranged on the lower head 5; the tube-side inlet pipe 9 is arranged on the upper head 4; the shell-side inlet pipe 2 and the shell-side outlet pipe 3 are both arranged on the shell 1; the liquid enters from the shell-side inlet pipe 2, exchanges heat through the heat exchange tube, and exits from the shell-side outlet pipe 3.

[0023] As an improvement, Figure 2 As shown, a plurality of horizontal baffle groups 11 are arranged in the housing 1, and the baffle group 11 includes a circular baffle 111 located in the center of the housing (see Figure 4 ) and an annular baffle 112 located around the shell (see Figure 3 ); along the upward flow direction of the gas, the ratio of the area of ​​the circular baffles in the baffle group to the area of ​​the annular baffles first gradually decreases and then gradually increases.

[0024] During the research process, it was found that the heat exchange of the baffles of the traditional heat exchanger is uneven in the cross section in the upward flow direction of the gas. The heat exchange effect is good in the parts around the bottom inlet and outlet, and the heat exchange effect is better in the middle center than in the surrounding edges. In the present invention, the area ratio of the circular baffles and the annular baffles in the baffle group changes along the upward flow direction of the gas. The fluid in the shell side gradually moves closer to the center in the middle, so that the heat exchange tubes around the shell at the center of the fluid strengthen the heat exchange, and then the heat exchange tubes at the center of the shell at the upper and lower ends strengthen the heat exchange, strengthening the heat exchange at the bottom inlet center and the top outlet. It changes the previous single heat exchange method from top to bottom, strengthens the heat exchange efficiency at different positions, makes the heat exchange uniform on the whole, and further achieves the purpose of strengthening heat transfer.

[0025] The above-mentioned area is the area projected onto the cross section of the shell, or the area projected onto a horizontal plane.

[0026] Preferably, at the center position in the vertical direction of the shell, the ratio of the area of ​​the circular baffle to the area of ​​the annular baffle reaches a maximum.

[0027] As an improvement, along the upward flow direction of the gas, the ratio of the area of ​​the circular baffles in the baffle group to the area of ​​the annular baffles gradually decreases with an increasing amplitude. The ratio of the area of ​​the circular baffles in the baffle group to the area of ​​the annular baffles gradually increases with an increasing amplitude. Through the above-mentioned amplitude changes, the overall heat exchange can be further made uniform, and the purpose of enhancing heat transfer can be further achieved.

[0028] As an improvement, the sum of the projected areas of the circular baffles and the annular baffles of the baffle group on the shell cross section is 110-120% of the shell cross section area.

[0029] As an improvement, the ratio of the area of ​​the circular baffles of the baffle group to the area of ​​the annular baffles is 0.8-1.2.

[0030] As an improvement, along the flow direction of the fluid in the tube, the spacing of the baffle group increases continuously from the tube entrance to the middle of the tube. Then from the middle of the tube to the tube exit, the spacing of the baffle group decreases continuously. Because in the countercurrent process, the heat exchange of the shell and tube per unit length along the flow process of the fluid is relatively uniform, so that the overall heat exchange effect is the best. However, it was found in experiments and simulations that the heat exchange in the middle is significantly greater than the heat exchange at the tube entrance and exit. Therefore, by changing the spacing of the baffles, the heat exchange area between the tube fluid and the shell fluid in the baffle also changes. Therefore, the uneven heat exchange is compensated by the change in area, thereby further improving the heat exchange efficiency.

[0031] As an improvement, along the flow direction of the fluid in the tube, from the tube entrance to the middle of the tube, the distance between the baffles increases. Then, from the middle of the tube to the tube exit, the distance between the baffles decreases. The above changes in the range can make the heat transfer per unit length of the entire fluid movement more uniform, further improving the heat transfer efficiency.

[0032] Preferably, the gas is flue gas or waste heat exhaust gas. Preferably, the liquid is liquid medicine, preferably used for fumigating wounds.

[0033] An expansion joint is provided in the middle of the shell to absorb the expansion difference between the tube side and the shell side.

[0034] The present invention is described below. Gas enters from the lower head 10 and enters the heat exchange tube 8, where it exchanges heat with the shell-side fluid. The heat carrier (i.e., liquid) is introduced into the shell-side inlet 2 to cool the heat exchange tube 8. After the heat carrier enters the shell side, the baffle 11 increases the turbulence of its flow between the tubes, thereby improving the heat transfer efficiency. After sufficient heat exchange, the heat carrier flows out from the outlet 3. After the heat release in the heat exchange tube 8 is completed, the gas is discharged from the upper head at the upper end of the heat exchange tube 8.

[0035] Although the present invention has been disclosed as above with preferred embodiments, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A gas-liquid shell and tube heat exchanger for heating liquid medicine, the shell and tube heat exchanger comprising a shell, a heat exchange tube, a shell-side inlet pipe and a shell-side outlet pipe; the shell-side inlet pipe and the shell-side outlet pipe are respectively located at the upper end and the lower end of the heat exchanger; the heat exchange tube is arranged in the shell, and the heat exchange tube is fixedly connected to the upper tube sheet and the lower tube sheet; the liquid enters from the shell-side inlet pipe, exchanges heat through the heat exchange tube, and exits from the shell-side outlet pipe; the gas enters the heat exchange tube from the lower head of the heat exchange tube, flows out from the upper head of the heat exchange tube, and the gas and liquid exchange heat, the gas is flue gas, the liquid is liquid medicine, and the flue gas heats the liquid medicine; it is characterized in that The shell side inlet pipe is arranged at the upper part of the shell, and a plurality of horizontal baffle groups are arranged in the shell, and the baffle group includes a circular baffle located at the center of the shell and an annular baffle located around the shell; along the upward flow direction of the gas, the ratio of the area of ​​the circular baffles in the baffle group to the area of ​​the annular baffles first gradually decreases and then gradually increases; along the upward flow direction of the gas, the ratio of the area of ​​the circular baffles in the baffle group to the area of ​​the annular baffles gradually decreases to a greater and greater extent; the ratio of the area of ​​the circular baffles in the baffle group to the area of ​​the annular baffles gradually increases to a smaller and smaller extent.

2. The shell and tube heat exchanger according to claim 1, characterized in that: At the center position in the vertical direction of the shell, the ratio of the area of ​​the circular baffle to the area of ​​the annular baffle reaches the maximum.

3. The shell and tube heat exchanger according to claim 1, characterized in that: The sum of the projected areas of the circular baffles and the annular baffles of the baffle group on the shell cross section is 110-120% of the shell cross section area.

4. The shell and tube heat exchanger according to claim 1, characterized in that: The ratio of the area of ​​the circular baffles of the baffle group to the area of ​​the annular baffles is 0.8-1.2.

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