Heat exchanger with controllable output temperature

Abstract

The invention provides a heat exchanger with controllable output temperature. The heat exchanger comprises a tube shell, a heat exchange tube, a shell pass inlet connecting tube and a shell pass outlet connecting tube, the heat exchange tube is arranged in the tube shell and is fixedly connected to the tube plate; the shell pass inlet is located at one end of the tube shell, the shell pass outlet comprises a first outlet and a second outlet, the first outlet is located at the other opposite end of the tube shell, and the second outlet is located in the middle of the tube shell; the first outlet is communicated with a first outlet pipe, a first outlet valve is arranged on the first outlet pipe, the second outlet is communicated with a second outlet pipe, a second outlet valve is arranged on the second outlet pipe, and the first outlet pipe and the second outlet pipe are communicated with the main outlet pipe. According to the invention, the fluid flow at different positions can be controlled through the valve, so that the outlet temperature is controlled.

Description

Technical Field

[0001] The invention relates to a shell and tube heat exchanger, in particular to a shell and tube cooler with controllable output temperature. 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] The shell and tube heat exchanger used in the heat exchange of hot and cold fluids, if using a conventional structure with only one shell outlet, has the following problems in heat exchange with the heat source or cold source. First, because the heat exchange area of ​​the tube bundle in the conventional shell and tube heat exchanger is basically fixed, it is difficult to control the temperature of the heat exchange medium at the shell outlet when the medium temperature and flow rate at the tube inlet and the heat exchange medium temperature and flow rate at the shell inlet remain unchanged. If the temperature of the heat source or cold source is too high or too low, the heat exchanger is prone to temperature instability, which has a great impact on the service life of the heat exchanger; second, because the different input fluid temperatures lead to different output temperatures, and because the flow rates are fixed, it is impossible to make timely adjustments or additional components need to be set separately.

[0004] However, traditional heat exchangers also have the above problems. Under the new energy-saving and emission-reduction situation, their development is greatly restricted. Therefore, in view of these shortcomings, a simple shell and tube heat exchanger is developed, which can dynamically adjust the output temperature of the heat exchanger shell, so that the heat exchange area and heat exchange efficiency can be effectively improved, which is of great significance to industrial production and energy-saving 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 novel structure, which can effectively control the output temperature of the shell side, 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 heat exchanger with controllable output temperature, comprising a tube shell, a heat exchange tube, a shell-side inlet pipe and a shell-side outlet pipe; the heat exchange tube is arranged in the tube shell, and the heat exchange tube is fixedly connected to the tube sheet; the shell-side inlet is located at one end of the tube shell, and is characterized in that the shell-side outlet comprises a first outlet and a second outlet, wherein the first outlet is located at the other end opposite to the tube shell, and the second outlet is located in the middle of the tube shell; the first outlet is connected to a first outlet pipe, a first outlet valve is arranged on the first outlet pipe, the second outlet is connected to a second outlet pipe, a second outlet valve is arranged on the second outlet pipe, and the first outlet pipe and the second outlet pipe are connected to a total outlet pipe.

[0008] As an improvement, a first temperature sensor is set at the first outlet, a second temperature sensor is set at the second outlet, and a third temperature sensor is set at the main outlet pipe. The controller controls the opening of the first outlet valve and the second outlet valve according to the temperatures monitored by the first temperature sensor, the second temperature sensor and the third temperature sensor, thereby controlling the outlet temperature to reach a predetermined temperature.

[0009] As an improvement, when the temperature detected by the third temperature sensor is lower than a predetermined temperature, the controller controls the opening of the first outlet valve to decrease and the opening of the second outlet valve to increase.

[0010] As an improvement, when the temperature detected by the third temperature sensor is higher than a predetermined temperature, the controller controls the opening of the first outlet valve to increase and the opening of the second outlet valve to decrease.

[0011] As an improvement, the controller is provided with a touch screen, and the touch screen displays the temperatures detected by the first temperature sensor, the second temperature sensor and the third temperature sensor.

[0012] As an improvement, the touch screen is provided in a human-computer interaction module, and the user can set the predetermined temperature through the human-computer interaction module.

[0013] As an improvement, a first tube communicating with the first outlet tube is provided between the first outlet valve and the first outlet, and a second tube communicating with the second outlet tube is provided between the second outlet valve and the second outlet.

[0014] As an improvement, the heat exchanger is a horizontal heat exchanger, the inlet is located at the lower part of the heat exchanger, and the first outlet and the second outlet are located at the upper part of the heat exchanger.

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

[0016] The present invention sets two outlets in the shell side, and the two outlets are at different positions, so that the fluids output from the two outlets participate in different heat exchange areas. The first outlet participates in the entire heat exchange, and the second outlet participates in a part of the heat exchange, thus resulting in different fluid temperatures output from the two outlets. By setting two outlet valves, the output fluid flow of the first outlet and the second outlet is controlled, so that the temperature of the mixed fluids with different temperatures in the total outlet pipe can be controlled, thereby controlling different output temperatures while keeping the output flow unchanged, avoiding the shortcomings of a single output temperature in the past, or controlling the output temperature by changing the output flow, and ensuring the amount of fluid output and the fluid temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the shell and tube heat exchanger of the present invention. DETAILED DESCRIPTION

[0018] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0019] In this article, unless otherwise specified, “ / ” represents division, and “×” and “*” represent multiplication.

[0020] Figure 1 The shell and tube heat exchanger of the present application is disclosed. Figure 1 As shown, a heat exchanger with controllable output temperature comprises a tube shell 1, a heat exchange tube 2, a tube side inlet 3 and a tube side outlet 4; the heat exchange tube is arranged in the tube shell 1, and the heat exchange tube is fixedly connected to the tube sheets at both ends of the tube shell; the shell side inlet 5 is located at one end of the tube shell, for example Figure 1 The shell outlet includes a first outlet 7 and a second outlet 6, wherein the first outlet 7 is located at the other end of the shell 1, for example Figure 1 As shown, it is located on the right side. The second outlet is located between the shell inlet 5 and the first outlet 7, and is preferably located in the middle of the shell; the first outlet is connected to the first outlet pipe 9, and the first outlet pipe 9 is provided with a first outlet valve 11, the second outlet 6 is connected to the second outlet pipe 8, and the second outlet pipe 8 is provided with a second outlet valve 10, and the first outlet pipe 11 and the second outlet pipe 10 are connected to the main outlet pipe 12.

[0021] The present invention sets two outlets in the shell side, and the two outlets are at different positions, so that the fluids output from the two outlets participate in different heat exchange areas. The first outlet participates in the entire heat exchange, and the second outlet participates in a part of the heat exchange, thus resulting in different fluid temperatures output from the two outlets. By setting two outlet valves, the output fluid flow of the first outlet and the second outlet is controlled, so that the temperature of the mixed fluids with different temperatures in the total outlet pipe can be controlled, thereby controlling different output temperatures while keeping the output flow unchanged, avoiding the shortcomings of a single output temperature in the past, or controlling the output temperature by changing the output flow, and ensuring the amount of fluid output and the fluid temperature.

[0022] Preferably, the second outlet fluid exchanges heat with one third to two thirds of the tube side area, and the first outlet fluid exchanges heat with 100% of the tube side area. As an improvement, the second outlet fluid participates in the heat exchange of one half of the tube side area.

[0023] As an improvement, a first temperature sensor is provided at the first outlet pipe 9, a second temperature sensor is provided at the second outlet pipe 8, and a third temperature sensor is provided at the main outlet pipe 12. The controller controls the opening of the first outlet valve 11 and the second outlet valve 10 according to the temperatures monitored by the first temperature sensor, the second temperature sensor and the third temperature sensor, thereby controlling the outlet temperature to reach a predetermined temperature.

[0024] As an improvement, the tube side is the heat source and the shell side is the cold source.

[0025] Both the heat source and the cold source are water.

[0026] As an improvement, when the temperature detected by the third temperature sensor is lower than the predetermined temperature, the controller controls the first outlet valve 11 to decrease the opening degree and the second outlet valve 10 to increase the opening degree. By increasing the flow rate of the high-temperature fluid and reducing the flow rate of the low-temperature fluid, the output temperature is increased to reach the predetermined temperature as soon as possible.

[0027] As an improvement, when the temperature detected by the third temperature sensor is higher than the predetermined temperature, the controller controls the first outlet valve 11 to increase the opening degree and the second outlet valve 10 to decrease the opening degree. By reducing the flow rate of the high-temperature fluid and increasing the flow rate of the low-temperature fluid, the output temperature is reduced to reach the predetermined temperature as soon as possible.

[0028] As an improvement, the controller is provided with a touch screen, and the touch screen displays the temperatures detected by the first temperature sensor, the second temperature sensor and the third temperature sensor. By displaying the temperatures, the user can make adjustments based on the temperatures.

[0029] As an improvement, the touch screen is provided with a human-computer interaction module, and the user can set a predetermined temperature through the human-computer interaction module. The user can input the temperature to be adjusted according to actual needs. By displaying the detected temperature, the user can also determine the achievable temperature, for example, the temperature of the first outlet is the highest temperature, and the temperature of the second outlet is the lowest temperature. Avoid users inputting unrealistic temperatures, such as lower than the lowest temperature or higher than the highest temperature.

[0030] As an improvement, a first pipe 13 connected to the first outlet pipe is provided between the first outlet valve and the first outlet, and a second pipe 15 connected to the second outlet pipe is provided between the second outlet valve and the second outlet. A first valve 14 is provided on the first pipe 13, and a second valve 16 is provided on the second pipe 15. Through the control of the first pipe, the second pipe and the valve, the function of directly outputting low-temperature and high-temperature fluids can be realized.

[0031] As an improvement, the heat exchanger is a horizontal heat exchanger, the inlet is located at the lower part of the heat exchanger, and the first outlet and the second outlet are located at the upper part of the heat exchanger.

[0032] A baffle 17 is disposed in the shell to allow the fluid to flow through the entire pipe path to avoid short circuit problems.

[0033] As an improvement, the shell side and the tube side are countercurrent flows. Along the flow direction of the fluid in the tube side, the spacing of the baffles 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 baffles decreases continuously. Because in the countercurrent process, the heat exchange of the shell side and the tube side 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 side inlet and outlet. Therefore, by changing the spacing of 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 is compensated by the change in area, thereby further improving the heat exchange efficiency.

[0034] 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 continuously. Then, from the middle of the tube to the tube exit, the distance between the baffles decreases continuously. The above changes in the range can make the heat exchange per unit length of the entire fluid movement more uniform, further improving the heat exchange efficiency.

[0035] The baffles are arranged in the vertical direction, including a baffle located at the upper part and a baffle located at the lower part, and the upper baffles and the lower baffles are arranged at intervals; along the flow direction of the cold water in the shell side, the vertical height of the lower baffle extending upward from the bottom shell side inner wall gradually increases, and the vertical length of the upper baffle extending downward from the upper shell side inner wall gradually decreases.

[0036] 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 direction of fluid flow. As the distance from the inlet increases, the density of the heat exchange liquid in the lower part of the shell is large, so the liquid flows downward, which significantly increases the heat exchange liquid in the lower part. Therefore, it is necessary to design a heat exchange structure for improvement. The present invention changes the height of the upper baffle and the lower baffle along the flow direction of the fluid, so that the liquid in the shell gradually moves closer to the center as it flows, so that the heat exchange tubes around the shell and tube center strengthen the heat exchange, which changes the previous heat exchange method, enhances the heat exchange efficiency at different positions, makes the heat exchange uniform as a whole, and further achieves the purpose of enhanced heat transfer.

[0037] As an improvement, along the flow direction of the fluid in the shell side, the vertical height of the lower baffle extending upward from the bottom shell side inner wall gradually increases, and the vertical length of the upper baffle extending downward from the upper shell side inner wall gradually decreases. Through the above-mentioned amplitude changes, the overall heat exchange can be further uniform, and the purpose of enhancing heat transfer can be further achieved.

[0038] 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 heat exchanger with controllable output temperature, comprising a tube shell, a heat exchange tube, a tube side inlet pipe and a tube side outlet pipe; the heat exchange tube is arranged in the tube shell, and the heat exchange tube is fixedly connected to the tube sheets at both ends of the tube shell; the shell side inlet is located at one end of the tube shell, characterized in that: The shell side outlet includes a first outlet and a second outlet, wherein the first outlet is located at the other end opposite to the tube shell, and the second outlet is located in the middle of the tube shell; the first outlet is connected to the first outlet pipe, and the first outlet pipe is provided with a first outlet valve, the second outlet is connected to the second outlet pipe, and the second outlet pipe is provided with a second outlet valve, and the first outlet pipe and the second outlet pipe are connected to the main outlet pipe.

2. The heat exchanger according to claim 1, characterized in that A first temperature sensor is provided at the first outlet pipe, a second temperature sensor is provided at the second outlet pipe, and a third temperature sensor is provided at the main outlet pipe. The controller controls the opening of the first outlet valve and the second outlet valve according to the temperatures monitored by the first temperature sensor, the second temperature sensor and the third temperature sensor, thereby controlling the outlet temperature to reach a predetermined temperature.

3. The heat exchanger according to claim 2, characterized in that When the temperature detected by the third temperature sensor is lower than a predetermined temperature, the controller controls the opening of the first outlet valve to decrease and the opening of the second outlet valve to increase.

4. The heat exchanger according to claim 3, characterized in that When the temperature detected by the third temperature sensor is higher than a predetermined temperature, the controller controls the opening of the first outlet valve to increase and the opening of the second outlet valve to decrease.

5. The heat exchanger according to claim 4, characterized in that The controller is provided with a touch screen, and the touch screen displays the temperatures detected by the first temperature sensor, the second temperature sensor and the third temperature sensor.

6. The heat exchanger according to claim 5, characterized in that The touch screen is set in the human-computer interaction module, and the user can set the predetermined temperature through the human-computer interaction module.

7. The heat exchanger according to claim 1, characterized in that: A first pipe communicating with the first outlet pipe is provided between the first outlet valve and the first outlet, and a second pipe communicating with the second outlet pipe is provided between the second outlet valve and the second outlet.

8. The heat exchanger according to claim 1, characterized in that The heat exchanger is a horizontal heat exchanger, the inlet is located at the lower part of the heat exchanger, and the first outlet and the second outlet are located at the upper part of the heat exchanger.

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