Shell and tube heat exchanger with rotating baffles

Abstract

The present invention provides a shell-and-tube heat exchanger with rotating baffles, comprising a shell and tube, 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 two ends of the heat exchanger; the heat exchange tubes are disposed in the shell and tube, and are fixedly connected to the tube sheet; the heat exchange tubes are characterized in that the upper and lower baffles and the left and right baffles are rotated at a certain angle around their respective baffle centerlines, i.e., the baffles are inclined at a certain angle to the vertical plane; the baffle centerline is the line connecting the vertex (center) of the sector and the midpoint of the arc of the sector. By rotating the baffle at a certain angle, the present invention can form a spiral-like baffle effect on the fluid, thereby improving the heat transfer coefficient.

Description

Technical Field

[0001] The invention relates to a shell and tube heat exchanger, in particular to a shell and tube heat exchanger with a fan-shaped baffle group. 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, the demand for heat exchangers in industrial production has increased in order to reduce energy consumption, and the quality requirements for heat exchangers have also become increasingly higher. In recent decades, although compact heat exchangers (plate, plate-fin, and press-welded plate heat exchangers, etc.), heat pipe heat exchangers, and direct contact heat exchangers 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 equipment still accounts for about 70% of all heat exchangers.

[0003] Shell-and-tube heat exchangers remain the mainstream type of heat exchange equipment due to their simple structure and ability to withstand high pressures. While the commonly used bow-shaped baffles are simple to manufacture, they suffer from flow dead zones, high flow resistance, and a large tube bundle support span at the notch, which can easily induce vibration damage. This has led to the emergence of many new tube bundle support solutions, including spiral baffles. Theoretically, spiral baffles are curved surfaces, making them difficult to manufacture. Currently, there are improved solutions for 1 / 4 elliptical / sector-shaped spiral baffles, where each layer of baffles consists of four 1 / 4 elliptical / sector-shaped baffles, connected end-to-end to form a shell-side spiral channel. Since shell-and-tube heat exchangers largely use the most compact tube bundles arranged in equilateral triangles, this creates significant difficulties in marking and positioning the inclined tube holes on the 1 / 4 elliptical / sector-shaped baffles, hindering the widespread application of this type of baffle.

[0004] The traditional shell channel is composed of fan-shaped baffles. Each fan-shaped baffle is at a certain angle to the axis of the shell. They are arranged in sequence from the front to the back of the shell. A "Z"-shaped space is formed between the fan-shaped baffles in two adjacent quadrants, and there is a certain gap (2 to 3 mm) between the baffles and the shell. Baffles with this structure often cause the flow medium to form a short-circuit diversion phenomenon at the inner wall of the shell and the boundary of the baffle. The short-circuit diversion reduces the flow rate of the spiral channel medium and weakens the heat exchange. It also causes the shell-side fluid to locally scour the baffles, causing the metal baffles to rust for a long time and affecting the water quality. In addition, baffles with this structure will cause the shell-side fluid to generate vortices at local locations, seriously affecting the heat exchange effect of the heat exchanger.

[0005] However, traditional baffle heat exchangers also have some shortcomings, such as high flow resistance, large dead zones, and low heat transfer efficiency. Therefore, their development is significantly restricted in the new energy conservation and emission reduction environment. Therefore, to address these shortcomings, a simple structure and mature process of baffle and shell-and-tube heat exchanger has been developed. This can effectively increase both the heat transfer area and heat transfer efficiency, which is of great significance to industrial production and energy conservation and emission reduction. Summary of the Invention

[0006] In order to overcome the defects and shortcomings in the prior art, the present invention provides a shell and tube heat exchanger with a novel 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.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows:

[0008] A shell and tube heat exchanger with a rotating baffle, the shell and tube heat exchanger comprising a shell and tube, 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 both ends of the heat exchanger; the heat exchange tubes are arranged in the shell and tube, and the heat exchange tubes are fixedly connected to the tube sheet; it is characterized in that the upper and lower baffles and the left and right baffles rotate around their respective baffle center lines at a certain angle, that is, the baffles are inclined at a certain angle to the vertical plane; the baffle center line is the line connecting the vertex (center of the circle) of the sector and the midpoint of the arc of the sector.

[0009] Preferably, the rotation angles of the symmetrically arranged upper baffle and lower baffle are opposite, and the rotation angles of the symmetrically arranged left baffle and right baffle are opposite.

[0010] Preferably, along the flow direction of the fluid, the angles at which the upper and lower baffles rotate around their respective baffle center lines first become smaller and then become larger, and the angles at which the left and right baffles rotate around their respective baffle center lines first become larger and then become smaller.

[0011] Preferably, in the middle position of the tube shell in the length direction, the rotation angle of the upper and lower baffles is the smallest, and the rotation angle of the left and right baffles is the largest; at the two ends of the tube shell in the length direction, the rotation angle of the upper and lower baffles is the largest, and the rotation angle of the left and right baffles is the smallest.

[0012] Preferably, at the middle position in the length direction of the tube shell, the rotation angle of the upper and lower baffles is 0, that is, they do not rotate and remain vertically arranged.

[0013] Preferably, the rotation angle of the left and right baffles is 20-35°. At both ends of the length direction of the tube shell, the rotation angle of the upper and lower baffles is 20-35°, and the rotation angle of the left and right baffles is 0, that is, they do not rotate and remain vertically arranged.

[0014] Preferably, a plurality of fan-shaped baffle groups are arranged in the tube shell, and the baffle groups include upper and lower baffles arranged in the vertical direction and left and right baffles arranged in the left and right directions, and the upper and lower baffles and the left and right baffles are spaced a certain distance apart; the upper and lower baffles include two fan-shaped baffles symmetrically arranged along the center line of the tube shell, and the left and right baffles include fan-shaped baffles symmetrically arranged along the center line of the tube shell.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] 1) The present invention can make the fluid form a spiral-like deflection effect by rotating a certain angle, thereby improving the heat transfer coefficient.

[0017] 2) The present invention changes the area of the upper and lower baffles and the inclination angle of the left and right baffles in the baffle group along the direction of fluid flow. This arrangement enhances heat exchange in the heat exchange tubes on the left and right sides of the shell, where the center of the fluid is located. Furthermore, heat exchange in the upper and lower positions of the shell inlet and outlet at the front and rear ends is enhanced. This enhances heat exchange at different locations, changing the traditional single heat exchange method and improving heat exchange efficiency at different locations. This results in uniform heat exchange overall, further achieving the goal of enhanced heat transfer.

[0018] 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 area change, thereby further improving the heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the heat exchange tube structure of the shell and tube heat exchanger with the baffle group provided in the present invention.

[0020] Figure 2 is a schematic top view of the baffle assembly of the present invention;

[0021] Figure 3 Schematic diagram of the upper and lower baffles of the present invention;

[0022] Figure 4 It is a schematic diagram of the left and right baffles of the present invention;

[0023] Figure 5 It is a schematic diagram of the control structure of the present invention. DETAILED DESCRIPTION

[0024] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0025] In this article, unless otherwise specified, “ / ” represents division, and “×” and “*” represent multiplication.

[0026] A shell and tube heat exchanger, such as Figure 1As shown, the shell and tube heat exchanger is arranged horizontally, including a tube shell 1, heat exchange tubes 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 on the left side of the upper end and the right side of the lower end of the tube shell 1; the heat exchange tubes 8 are arranged in the tube shell 1, and the heat exchange tubes are fixedly connected to the left tube sheet and the right tube sheet; the front end of the left tube sheet is connected to the left header 4, and the rear end of the right tube sheet is connected to the right header 5; the tube-side outlet pipe 10 is arranged on the left header 4; the tube-side inlet pipe 9 is arranged on the right header 5; the shell-side inlet pipe 2 and the shell-side outlet pipe 3 are both arranged on the tube shell 1; the gas enters from the shell-side inlet pipe 2, exchanges heat through the heat exchange tubes, and exits from the shell-side outlet pipe 3.

[0027] like Figure 2 As shown, a plurality of fan-shaped baffle groups 6 are arranged in the tube shell, and the fan-shaped baffle groups include upper and lower baffles 61 arranged in the vertical direction and left and right baffles 62 arranged in the left and right direction. The upper and lower baffles 61 and the left and right baffles 62 are spaced a certain distance apart; the upper and lower baffles include two fan-shaped baffles 61 symmetrically arranged along the center line of the tube shell, and the left and right baffles include fan-shaped baffles 62 symmetrically arranged along the center line of the tube shell.

[0028] As an improvement, the vertices (centers of circles) of the upper and lower baffles and the left and right baffles are located on the center line of the tube shell, that is, the line formed by the center points of the cross section.

[0029] Normally, the baffles are arranged vertically. As an improvement, the upper and lower baffles and the left and right baffles are rotated a certain angle around their respective baffle centerlines, that is, the baffles are tilted at a certain angle relative to the vertical plane. The baffle centerline is the line connecting the vertex (center) of the sector and the midpoint of the arc of the sector. By rotating the baffle at a certain angle, the fluid can form a spiral baffle effect, improving the heat transfer coefficient.

[0030] As an improvement, the symmetrically arranged upper and lower baffles rotate at opposite angles, and the symmetrically arranged left and right baffles rotate at opposite angles. For example, when viewed from above, if the upper baffle rotates clockwise, the lower baffle rotates counterclockwise. Alternatively, when viewed from a horizontal direction, if the left baffle rotates clockwise, the right baffle rotates counterclockwise.

[0031] As an improvement, along the flow direction of the fluid, the angles at which the upper and lower baffles rotate around their respective baffle centerlines first decrease, then increase, while the angles at which the left and right baffles rotate around their respective baffle centerlines first increase, then decrease. Through the above arrangement, heat exchange is enhanced in the heat exchange tubes on the left and right sides of the shell at the center of the fluid, and then in the upper and lower positions of the shell inlet and outlet at the front and rear ends. This enhances heat exchange at different locations, changing the previous single heat exchange method and enhancing the heat exchange efficiency at different locations. This results in uniform heat exchange overall, further achieving the goal of enhanced heat transfer.

[0032] As an improvement, the rotation angles of the upper and lower baffles are smallest and the left and right baffles are largest in the middle of the shell length. At the two ends of the shell length, the rotation angles of the upper and lower baffles are largest and the left and right baffles are smallest.

[0033] As an improvement, in the middle of the tube shell's length, the upper and lower baffles rotate at an angle of 0°, meaning they do not rotate and remain vertically positioned. The left and right baffles rotate at an angle of 20-35°. At both ends of the tube shell's length, the upper and lower baffles rotate at an angle of 20-35°, while the left and right baffles rotate at an angle of 0°, meaning they do not rotate and remain vertically positioned.

[0034] Through the above-mentioned setting, the heat transfer amount can be optimized and the heat transfer coefficient can be further improved.

[0035] As an improvement, along the flow direction of the fluid in the shell side, the ratio of the area of the upper and lower baffles to the area of the left and right baffles in the baffle group gradually increases first, and then gradually decreases after reaching a certain position.

[0036] During the research process, it was found that the heat exchange of the baffles of the traditional heat exchanger was uneven in the cross section in the flow direction, with good heat exchange effect on the left and right sides of the inlet and outlet, and good heat exchange effect in the middle upper and lower positions. In the present invention, along the flow direction of the fluid, the area ratio of the upper and lower baffles in the baffle group to the area ratio of the left and right baffles first gradually increases, and then gradually decreases, so that the fluid in the shell gradually moves closer to the left and right sides in the middle, so that the heat exchange tubes on the left and right sides of the shell at the center of the fluid strengthen the heat exchange, and then the heat exchange tubes at the upper and lower positions of the shell inlet and outlet at the front and rear ends strengthen the heat exchange. According to different positions, the heat exchange at different positions is strengthened, which changes the previous single heat exchange mode, 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.

[0037] The above-mentioned area is the area projected onto the cross section of the shell, or the area projected onto the vertical plane.

[0038] Preferably, at the center position of the fluid flow direction in the shell, the ratio of the area of the upper and lower baffles to the area of the left and right baffles reaches the maximum.

[0039] As an improvement, the distance between the upper and lower baffles 61 and the left and right baffles 62 is 0.6-0.9 times the diameter of the tube shell, preferably 0.8 times.

[0040] As an improvement, the certain position is a middle position of the tube shell.

[0041] As an improvement, along the flow direction of the fluid in the shell side, the area ratio of the upper and lower baffles to the area ratio of the left and right baffles is gradually increased. By changing the above range, the overall heat exchange can be further uniformed, further achieving the purpose of enhancing heat transfer.

[0042] As an improvement, along the flow direction of the shell-side fluid, the ratio of the area of the upper and lower baffles to the area of the left and right baffles gradually decreases. By changing the above range, the overall heat exchange can be further uniformed, further achieving the purpose of enhancing heat transfer.

[0043] As an improvement, the sum of the fan-shaped angles of the baffle group is 170-190°. Figure 2 The sum of the included angles of the four fan-shaped baffles is 170-190°.

[0044] As an improvement, the sum of the fan-shaped angles of the baffle group is 180°.

[0045] As an improvement, the area ratio of the upper and lower baffles to the left and right baffles is 0.9-1.2.

[0046] By optimizing the above parameters, the heat exchange efficiency can be optimized.

[0047] As an improvement, the shell side and the tube side are in countercurrent flow. Along the flow direction of the fluid in the tube side, the spacing of the baffle groups increases continuously from the tube side inlet to the middle of the tube side. Then, from the middle of the tube side to the tube side outlet, the spacing of the baffle groups decreases continuously. Because in the countercurrent process, the heat exchange rate of the shell side and the tube side per unit length along the flow process of the fluid is relatively uniform, which makes the overall heat exchange effect the best. However, in experiments and simulations, it was found that the heat exchange rate in the middle is significantly greater than the heat exchange rate at the tube side inlet and outlet. Therefore, 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 rate is compensated by the change in area, thereby further improving the heat exchange efficiency.

[0048] As an improvement, along the flow direction of the fluid within the tube, the spacing between the baffles increases in magnitude from the tube inlet to the middle. Then, from the middle to the tube outlet, the spacing between the baffles decreases in magnitude. This variation in magnitude makes the heat transfer per unit length of the entire fluid flow more uniform, further improving heat transfer efficiency.

[0049] As an improvement, the heat exchanger is an injection water cooling device, with injection water in the tube side and cold water in the shell side, and the injection water is cooled by the cold water.

[0050] As an improvement, the shell side is the heat source and the tube side is the cold source.

[0051] As an improvement, the heat exchanger further comprises a control system, which controls the flow rate of the heat source entering the shell side of the heat exchanger according to the outlet temperature of the tube side.

[0052] As an improvement, the control system includes: a temperature sensor 13, a flow controller 14 and a central controller 12, the flow controller controls the flow rate of the heat source entering the heat exchanger; the temperature sensor is used to measure the outlet temperature of the tube-side cold source, when the cold source temperature is lower than the first temperature, the flow controller is fully opened, when the cold source outlet temperature reaches the first temperature, the central controller controls the flow controller to reach a first flow rate, the first flow rate is lower than the flow rate of all openings, when the cold source outlet temperature reaches a second temperature higher than the first temperature, the central controller controls the flow rate to reach a second flow rate lower than the first flow rate controller, when the cold source outlet temperature reaches a third temperature higher than the second temperature, the central controller controls the flow controller to reach a third flow rate lower than the second flow rate, when the cold source outlet temperature reaches a fourth temperature higher than the third temperature, the central controller controls the flow controller to reach a fourth flow rate lower than the third flow rate; when the cold source outlet temperature reaches a fifth temperature higher than the fourth temperature, the central controller closes the flow controller to prevent water from entering the heat exchanger.

[0053] The fifth temperature is the temperature exceeding the upper limit of the predetermined data, and the first temperature is the temperature below the lower limit of the predetermined data. Through the above settings, the heat exchange capacity of the heat exchanger can be controlled according to the temperature, thereby achieving the effect of saving heat source.

[0054] As an improvement, the control system may be a single chip microcomputer, and a control panel may be provided. The control panel may be provided on the upper part or the lower part of the heat exchanger, or on the pipe entering the heat exchanger.

[0055] Although the present invention has been disclosed above with reference to preferred embodiments, the present invention is not limited thereto. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope defined by the claims.

Claims

1. A shell and tube heat exchanger with a rotating baffle, wherein the shell and tube heat exchanger is arranged horizontally, and comprises a tube 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 both ends of the heat exchanger; the heat exchange tube is arranged in the tube shell, and the heat exchange tube is fixedly connected to the tube sheet; a plurality of fan-shaped baffle groups are arranged in the tube shell, and the fan-shaped baffle groups include upper and lower baffles arranged in the vertical direction and left and right baffles arranged in the left and right directions, and the upper and lower baffles and the left and right baffles are spaced a certain distance apart; the upper and lower baffles include two fan-shaped baffles symmetrically arranged along the center line of the tube shell, and the left and right baffles include fan-shaped baffles symmetrically arranged along the center line of the tube shell, characterized in that The upper and lower baffles and the left and right baffles rotate around their respective baffle center lines at a certain angle, that is, the baffles are inclined at a certain angle to the vertical plane; the baffle center line is the line connecting the vertex of the fan and the midpoint of the arc of the fan; along the flow direction of the fluid, the angles at which the upper and lower baffles rotate around their respective baffle center lines first become smaller and then become larger, and the angles at which the left and right baffles rotate around their respective baffle center lines first become larger and then become smaller; the shell side and the tube side flow in countercurrent, and along the flow direction of the fluid in the tube side, the spacing of the baffle groups increases continuously from the tube side inlet to the middle position of the tube side; then from the middle position of the tube side to the tube side outlet, the spacing of the baffle groups decreases continuously.

2. The shell and tube heat exchanger with rotating baffles according to claim 1, characterized in that: The rotation angles of the symmetrically arranged upper baffle and the lower baffle are opposite, and the rotation angles of the symmetrically arranged left baffle and the right baffle are opposite.

3. The shell and tube heat exchanger with rotating baffles according to claim 1, characterized in that: In the middle position of the tube shell in the longitudinal direction, the rotation angle of the upper and lower baffles is the smallest, and the rotation angle of the left and right baffles is the largest; at the two ends of the tube shell in the longitudinal direction, the rotation angle of the upper and lower baffles is the largest, and the rotation angle of the left and right baffles is the smallest.

4. The shell and tube heat exchanger with rotating baffles according to claim 1, characterized in that: The rotation angle of the left and right baffles is 20-35°.

Images