Shell and tube condenser with automatic removal of liquid film

Abstract

The present application relates to heat exchanger technical field, disclose a kind of automatically removes liquid film shell and tube condenser, including shell, one end of shell is equipped with cold water inlet, the other end is equipped with cold water outlet, shell upper end is equipped with air inlet, lower end is connected with liquid outlet pipe, shell is equipped with gas equalizing cover, finned tube one and finned tube two in, gas equalizing cover is equipped with multiple gas equalizing holes, gas equalizing cover separates the inner cavity of shell into first cavity and second cavity, first cavity is equipped with finned tube two, second cavity is equipped with finned tube one, and the outer wall of finned tube one is equipped with liquid guide fin.The continuity of liquid film is actively destroyed by setting finned tube one and using liquid guide fin on finned tube one, so that liquid film does not accumulate and grow outside the tube, but accumulates into liquid guide fin in the form of droplets, effectively solve the problem of thermal resistance caused by liquid film covering, and the heat transfer efficiency of the overall equipment is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger technology, and more specifically to a shell-and-tube condenser with automatic liquid film removal. Background Technology

[0002] Shell-and-tube condensers are widely used in chemical, refrigeration, and other fields. Their heat transfer performance directly affects the energy efficiency and economic operation of the entire system. In the gas-liquid condensation process, the gaseous working fluid undergoes a phase change on the outer surface of the low-temperature tube wall, exchanging heat. Existing shell-and-tube condensers have the following drawbacks: As the condenser's operating time increases, the thickness of the continuous liquid film formed by the gaseous working fluid condensing on the outer wall of the tube continuously increases. This covering effect significantly hinders the direct contact between the gaseous working fluid and the cooling surface, leading to a significant decrease in the heat transfer coefficient and limiting the equipment's heat transfer performance. Experimental studies show that the liquid film thermal resistance accounts for as much as 60%-80% of the total thermal resistance, severely restricting the equipment's heat exchange performance. The compressor exhaust has a certain degree of superheat. The superheated working fluid entering the condenser first cools to saturation, and its heat transfer process does not involve a phase change, resulting in low heat transfer efficiency and leading to an excessively large condenser shell. In the condenser outlet area, the lack of an effective subcooling structure design makes it difficult for the condensed liquid to be further cooled below the saturation temperature. Insufficient subcooling will cause the liquid to flash evaporate in the subsequent process, affecting the stability of the system and causing energy waste. Summary of the Invention

[0003] This invention addresses the existing technical problems by providing a shell-and-tube condenser that automatically removes the liquid film.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A shell-and-tube condenser with automatic liquid film removal includes a shell, one end of which is provided with a cold water inlet and the other end with a cold water outlet. An air inlet is provided at the upper end of the shell, and a liquid outlet pipe is connected to the lower end of the shell. A gas equalization hood, a finned tube one, and a finned tube two are provided inside the shell. The gas equalization hood is provided with a plurality of gas equalization holes. The gas equalization hood divides the inner cavity of the shell into a first cavity and a second cavity. The finned tube two is provided in the first cavity, and the finned tube one is provided in the second cavity. Liquid guiding fins are provided on the outer wall of the finned tube one.

[0005] Based on the above technical solution, the present invention can be further improved as follows:

[0006] Preferably, a liquid storage bag is installed at the lower end of the housing, and a partition plate and an integrated subcooling unit are provided inside the housing. The partition plate is located at one end near the cold water inlet, and the partition plate cooperates with the inner wall of the housing to form a subcooling cavity. The integrated subcooling unit is located inside the subcooling cavity and is connected to the liquid storage bag.

[0007] Preferably, the air distribution hood is coaxially arranged with the housing, and the upper end of the air distribution hood is provided with two parallel air distribution plates, the height of which gradually decreases from the air inlet along the axial direction to both sides.

[0008] Preferably, the plurality of finned tubes are arranged in a square matrix within the second cavity.

[0009] Preferably, each of the finned tubes is provided with two liquid guiding fins, which are disposed in the detachment zone of the finned tube.

[0010] Preferably, the total height of the liquid-guiding fins in the radial direction is H. ;

[0011] H—Total height of the liquid-guiding fins in the radial direction, in meters; —Wall thickness of finned tube 1, in meters.

[0012] Preferably, the thickness of the liquid-guiding fins gradually decreases in the radial direction, and the thickness of the liquid-guiding fins is T. ;

[0013] Where: T—thickness of the liquid guiding fin, m; H—total height of the liquid guiding fin in the radial direction, m;

[0014] — Wall thickness of finned tube 1, m; h — Height of the liquid-conducting fin at a certain radius in the radial direction, m.

[0015] Preferably, the finned tubes are arranged in a ring within the first cavity, and the distance between adjacent finned tubes is S. ;

[0016] In the formula: —Outer diameter of the shell, in meters; —Outer diameter of the equalization hood, in meters;

[0017] — Spacing of the circular array, in meters; —The saturation temperature of the working fluid, in K; —Temperature of the working fluid inlet, K.

[0018] Preferably, the inner diameter of the second finned tube is , ;

[0019] In the formula: —Inner diameter of finned tube II, in meters; —Outer diameter of the shell, in meters;

[0020] —Outer diameter of the equalization hood, in meters; — Convection heat transfer coefficient inside the pipe, W / m2 ·K; — Convective heat transfer coefficient outside the tube, W / m 2 ·K.

[0021] Preferably, the integrated subcooling unit includes two rows of tube bundles that extend radially along the housing and are staggered.

[0022] The beneficial effects of this invention are as follows: This invention actively disrupts the continuity of the liquid film by setting up finned tubes and adding liquid-guiding fins on them. This prevents the liquid film from accumulating and growing outside the tubes, instead causing it to accumulate in the liquid-guiding fins and drip down as droplets. This effectively solves the thermal resistance problem caused by liquid film coverage, significantly improving the overall heat transfer efficiency of the equipment. Furthermore, this invention achieves precise zoning by setting up a gas equalization hood, enabling accurate management of each thermal process. Gas passes through different chambers to achieve superheating, condensation, and subcooling, ensuring sufficient subcooling of the outlet liquid. Finally, this invention uses a built-in gas equalization hood and optimizes the tube bundle arrangement to achieve uniform flow field distribution. This ensures that the gaseous working fluid is evenly distributed around each finned tube after entering the condenser, avoiding excessively high or low local concentrations. This improves the overall heat transfer performance of the condenser, ensuring sufficient contact and efficient heat exchange between the gas and liquid phases within the condenser, further enhancing the operational stability and economy of the equipment. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the shell-and-tube condenser for automatic liquid film removal according to the present invention.

[0024] Figure 2 This is a cross-sectional schematic diagram of the shell-and-tube condenser with automatic liquid film removal according to the present invention;

[0025] Figure 3 This is a schematic cross-sectional view of the finned tube of the present invention;

[0026] Figure 4 This is a cross-sectional view of the finned tube II of the present invention;

[0027] Figure 5 This is a front view of the integrated subcooling unit of the present invention;

[0028] Figure 6 This is a side view of the integrated subcooling unit of the present invention;

[0029] Figure 7 This is a schematic diagram of the gas equalization hood of the present invention.

[0030] Reference numerals: 1. Cold water outlet; 2. Air inlet; 3. Gas distribution hood; 31. Gas distribution plate; 4. Integrated subcooling unit; 41. Tube bundle; 5. Cold water inlet; 6. Liquid outlet pipe; 7. Regulating valve; 8. Liquid storage tank; 9. Finned tube one; 91. Liquid guiding fin; 10. Support; 11. Divider plate; 12. Upper liquid level gauge port; 13. Lower liquid level gauge port; 14. Shell; 15. Finned tube two; 16. First cavity; 17. Second cavity; 18. Subcooling cavity; 19. Impact zone; 20. Thermal development zone; 21. Detachment zone. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0032] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0033] like Figures 1 to 7 As shown, this invention discloses a shell-and-tube condenser with automatic liquid film removal, including a shell 14, which is mounted on a support 10. One end of the shell 14 is provided with a cold water inlet 5, and the other end is provided with a cold water outlet 1. The shell 14 is provided with an air inlet 2. The lower end of the shell 14 is connected to a liquid outlet pipe 6. The shell 14 is provided with a gas equalization hood 3, a finned tube 1 9, and a finned tube 2 15. The gas equalization hood 3 is provided with multiple gas equalization holes. The gas equalization hood 3 divides the inner cavity of the shell 14 into a first cavity 16 and a second cavity 17. The first cavity 16 is formed between the gas equalization hood 3 and the inner wall of the shell 14. The second finned tube 2 15 is provided in the first cavity 16. The inner side of the gas equalization hood 3 is the second cavity 17. The second cavity 17 is provided with a finned tube 1 9. The outer wall of the finned tube 1 9 is provided with liquid guiding fins 91. The liquid guiding fins 91 extend along the axial direction of the finned tube 1 9 to prevent the liquid film thickness from increasing and optimize heat transfer.

[0034] Furthermore, a liquid storage tank 8 is installed at the lower end of the shell 14. A partition plate 11 and an integrated subcooling unit 4 are provided inside the shell 14. The partition plate 11 is located at the end near the cold water inlet 5. The partition plate 11 and the inner wall of the shell 14 cooperate to form a subcooling cavity 18. The subcooling cavity 18 is located at the end near the cold water inlet 5. The integrated subcooling unit 4 is located inside the subcooling cavity 18. The integrated subcooling unit 4 is connected to the liquid storage tank 8 through a pipeline. The saturated liquid working fluid is cooled by the integrated subcooling unit 4. A regulating valve 7 is installed on the pipeline to regulate the subcooling degree of the working fluid.

[0035] In this embodiment, the integrated subcooling unit 4 includes two rows of tube bundles 41. The two rows of tube bundles 41 extend along the radial direction of the housing 14 and are staggered. The angle between the center line of the two staggered tube bundles 41 and the horizontal plane is β, where β is 30°. This staggered arrangement can increase the flow path of the working fluid in the integrated subcooling unit 4, increase the heat exchange area, enhance the subcooling effect, and enable the condensed liquid working fluid to further reduce its temperature and obtain sufficient subcooling, thereby avoiding subsequent flash evaporation and ensuring stable system operation.

[0036] Furthermore, an upper level gauge 12 is provided above the liquid storage tank 8, and a lower level gauge 13 is provided below it. The level gauges monitor the liquid level in the liquid storage tank 8 in real time, so as to adjust the flow rate of the working fluid and the degree of subcooling in a timely manner to ensure the stable operation of the system. When the liquid level is too high, the flow rate of the working fluid entering the integrated subcooling unit 4 can be increased through the regulating valve 7 to ensure that the integrated subcooling unit 4 has enough working fluid for heat exchange; when the liquid level is too low, the flow rate of the working fluid flowing into the integrated subcooling unit 4 is reduced, thereby maintaining the subcooling effect of the system.

[0037] In practical engineering applications, a working fluid with a certain degree of superheat enters the first chamber 16 through the inlet 2 and exchanges heat through the finned tubes 15. Cold water flows inside the finned tubes 15, while the working fluid flows outside the tubes to cool the superheated steam entering through the inlet 2. By increasing the number of finned tubes 15, the heat transfer coefficient on the gas phase side is increased, improving the overall heat transfer efficiency. Compared with existing shell-and-tube condensers, the overall volume is reduced. After the working fluid is cooled to saturation in the first chamber 16, it enters the second chamber through the vapor distribution shroud 3. In the second chamber 17, the working fluid and cold water exchange heat through finned tube 9 to condense the gaseous working fluid. Because the outer wall of finned tube 9 is provided with liquid guiding fins 91, the liquid film of the working fluid cannot accumulate on the outer wall of finned tube 9, so that the liquid working fluid drips rapidly along the liquid guiding fins 91. Then, the condensed gaseous working fluid becomes liquid and gathers in the liquid storage tank 8 below. A part of the liquid in the liquid storage tank 8 enters the integrated subcooling unit 4 through the pipeline for cooling, increasing the subcooling degree of the working fluid. The subcooled working fluid is output through the liquid outlet pipe 6.

[0038] In this embodiment, the gas equalization hood 3 is coaxially arranged with the shell 14. The upper end of the gas equalization hood 3 is provided with two parallel gas equalization plates 31. The height of the gas equalization plates 31 gradually decreases from the air inlet 2 along the axial direction to both sides, so that the gas phase working fluid enters the first cavity 16 evenly along the axial direction, avoiding the situation of excessively high local concentration, ensuring that the gas phase working fluid is evenly distributed in the condenser, thereby improving the overall heat transfer efficiency of the condenser.

[0039] The condensation heat transfer characteristics of the surface vary along the circumference of the finned tube 9 according to the local heat transfer coefficient. Taking one side of the finned tube 9 as an example, it is mainly divided into three regions: the impact zone 19 (0°-40°), the thermal development zone 20 (40°-120°), and the separation zone 21 (120°-180°). Among them, the heat transfer performance of the separation zone 21 (120°-180°) is the worst, which is the main reason for the heat transfer resistance. In this invention, liquid-guiding fins 91 are set in the separation zone 21 of the finned tube 9, so that the condensed working fluid in the separation zone 21 does not adhere to the tube wall, but drips through the liquid-guiding fins 91, thereby improving the heat transfer efficiency. In this embodiment, two liquid-guiding fins 91 are set in the separation zone 21. Specifically, the angle between the liquid-guiding fins 91 and the vertical direction is α, where α is 60°, so that the condensed working fluid can slide smoothly on the surface of the liquid-guiding fins 91 and avoid accumulation on the outer wall of the finned tube 9.

[0040] Furthermore, the total height of the liquid-guiding fins 91 in the radial direction is H, where H=2. Wherein, H—the total height of the liquid-guiding fin 91 in the radial direction, in meters; —The wall thickness of finned tube 9, in meters. This ensures that the liquid-conducting fins 91 can fully disrupt the continuity of the liquid film, thereby improving the overall heat exchange efficiency.

[0041] Furthermore, the thickness of the liquid-guiding fin 91 gradually decreases along the radial direction, and the thickness of the liquid-guiding fin 91 is T. ;

[0042] Where: T—thickness of liquid guiding fin 91, m; H—total height of liquid guiding fin 91 in the radial direction, m;

[0043] — Wall thickness of finned tube 9, m; h — Height of liquid-conducting fin 91 at a certain radius in the radial direction, m.

[0044] The thickness of the liquid guiding fin 91 varies with the height of the liquid guiding fin 91 in the radial direction. This thickness variation design helps the working fluid droplets to flow and drip smoothly on the liquid guiding fin 91, further improving the liquid film removal effect.

[0045] In this embodiment, multiple finned tubes 9 are arranged in a square matrix within the second cavity 17, ensuring sufficient contact between the gaseous working fluid and the finned tubes 9, thereby improving condensation efficiency. The square matrix arrangement ensures uniform spacing between the finned tubes 9, facilitating uniform distribution and flow of the gaseous working fluid and preventing localized flow dead zones or excessively fast or slow flow rates, thus guaranteeing the stability and efficiency of the condensation process. Simultaneously, this arrangement facilitates the installation and maintenance of the finned tubes 9, reducing manufacturing and operating costs. In practical applications, the arrangement and spacing of the finned tubes 9 can be optimized according to specific needs and operating conditions to achieve the best condensation effect.

[0046] To avoid affecting the gas equalization effect of the gas equalization hood 3, the finned tubes 15 are arranged in a ring around the axis of the shell 14 within the first cavity 16. If the finned tubes 15 are arranged too densely, it will affect the gas equalization effect of the gas equalization hood 3; if they are arranged too sparsely, the superheated steam cannot be completely cooled to saturation. Therefore, the spacing of the ring array has a certain impact on the heat exchange effect of this invention. The spacing between adjacent finned tubes 15 is... , ;

[0047] In the formula: —Outer diameter of shell 14, in meters; —Outer diameter of the equalization hood 3, in meters;

[0048] — Spacing of the circular array, in meters; —The saturation temperature of the working fluid, in K; —Temperature of the working fluid inlet, K. A reasonable spacing design ensures sufficient heat exchange of the working fluid within the first cavity 16, while also ensuring a uniform flow field distribution.

[0049] Furthermore, the maximum radial cross-sectional area of ​​the fins on finned tube 2 15 is 5-8 times the cross-sectional area of ​​the tube's outer diameter to enhance heat exchange. The inner diameter of finned tube 2 15 is... , ;

[0050] In the formula: —Inner diameter of finned tube 215, in meters; —Outer diameter of shell 14, in meters; —Outer diameter of the equalization hood 3, in meters; — Convection heat transfer coefficient inside the pipe, W / m 2 ·K; — Convective heat transfer coefficient outside the tube, W / m 2 • K. It can optimize the heat exchange performance of finned tube 215 and improve the overall heat transfer efficiency of the condenser.

[0051] In summary, this invention achieves highly efficient gas-liquid two-phase heat exchange and automatic liquid film removal. Through the synergistic effect of the gas equalization shroud 3, finned tube 1 9, and finned tube 2 15, uniform distribution and sufficient heat exchange of the working fluid within the condenser are ensured. The inclined design of the gas equalization plate 31 on the gas equalization shroud 3 effectively avoids excessively high local concentrations of the gaseous working fluid, improving heat transfer efficiency. The liquid-guiding fins 91 on the finned tube 1 9 disrupt the continuity of the liquid film, enabling rapid droplet dripping and preventing liquid film accumulation and thickening, thus improving heat transfer efficiency. The annular arrangement and reasonable spacing design of the finned tube 2 15 further optimize the heat transfer path and flow field distribution of the working fluid. The introduction of the integrated subcooling unit 4 allows the condensed liquid working fluid to further reduce its temperature, achieving sufficient subcooling and avoiding subsequent flash evaporation, ensuring stable system operation. Therefore, this invention not only improves the overall heat transfer efficiency of the condenser but also reduces the manufacturing and operating costs of the equipment.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A shell-and-tube condenser with automatic liquid film removal, comprising a shell (14), one end of which is provided with a cold water inlet (5) and the other end with a cold water outlet (1), the upper end of which is provided with an air inlet (2), and the lower end of which is connected to a liquid outlet pipe (6), characterized in that, The housing (14) is provided with a gas equalization hood (3), a finned tube one (9), and a finned tube two (15). The gas equalization hood (3) is provided with multiple gas equalization holes. The gas equalization hood (3) divides the inner cavity of the housing (14) into a first cavity (16) and a second cavity (17). The gas equalization hood (3) and the inner wall of the housing (14) form the first cavity (16). The inner side of the gas equalization hood (3) is the second cavity (17). The working fluid enters the first cavity (16) through the air inlet (2). The first cavity (16) is provided with the finned tube two (15). The second cavity (17) is provided with the finned tube one (9). The outer wall of the finned tube one (9) is provided with liquid guiding fins (91). A liquid storage bag (8) is installed at the lower end of the body (14). A partition plate (11) and an integrated subcooling unit (4) are provided inside the housing (14). The partition plate (11) is located at the end near the cold water inlet (5). The partition plate (11) and the inner wall of the housing (14) cooperate to form a subcooling cavity (18). The integrated subcooling unit (4) is located inside the subcooling cavity (18). The integrated subcooling unit (4) is connected to the liquid storage bag (8). The condensed gaseous working fluid becomes liquid and accumulates in the liquid storage bag (8) below. A portion of the liquid in the liquid storage bag (8) enters the integrated subcooling unit (4) through a pipeline for cooling. The subcooled working fluid is output through the liquid outlet pipe (6).

2. The shell-and-tube condenser with automatic liquid film removal according to claim 1, characterized in that, The gas equalization hood (3) is coaxially arranged with the housing (14). The upper end of the gas equalization hood (3) is provided with two parallel gas equalization plates (31). The height of the gas equalization plates (31) gradually decreases from the air inlet (2) along the axial direction to both sides.

3. The shell-and-tube condenser with automatic liquid film removal according to claim 1, characterized in that, Multiple finned tubes (9) are arranged in a square matrix within the second cavity (17).

4. The shell-and-tube condenser with automatic liquid film removal according to claim 1 or 3, characterized in that, Each of the finned tubes (9) is provided with two liquid guiding fins (91), which are located in the detachment zone (21) of the finned tube (9).

5. The shell-and-tube condenser with automatic liquid film removal according to claim 4, characterized in that, The total height of the liquid-guiding fins (91) in the radial direction is H. ; H—Total height of the liquid guiding fin (91) in the radial direction, m; —Wall thickness of finned tube 1 (9), m.

6. The shell-and-tube condenser with automatic liquid film removal according to claim 5, characterized in that, The thickness of the liquid-guiding fin (91) gradually decreases in the radial direction, and the thickness of the liquid-guiding fin (91) is T. ; Where: T—thickness of the liquid guiding fin (91), m; H—total height of the liquid guiding fin (91) in the radial direction, m; — Wall thickness of finned tube (9), m; h — Height of liquid-conducting fin (91) at a certain radius in the radial direction, m.

7. The shell-and-tube condenser with automatic liquid film removal according to claim 1, characterized in that, The finned tubes (15) are arranged in a ring within the first cavity (16), and the distance between adjacent finned tubes (15) is S. ; In the formula: —Outer diameter of the shell (14), m; —Outer diameter of the equalization hood (3), m; — Spacing of the ring array, m; Ts — Saturation temperature of the working fluid, K; —Temperature of the working fluid inlet, K.

8. The shell-and-tube condenser with automatic liquid film removal according to claim 7, characterized in that, The inner diameter of the finned tube 2 (15) is , ; In the formula: —Inner diameter of finned tube 2 (15), m; —Outer diameter of the shell (14), m; —Outer diameter of the equalization hood (3), m; — Convection heat transfer coefficient inside the pipe, W / m 2 ·K; — Convective heat transfer coefficient outside the tube, W / m 2 ·K.

9. The shell-and-tube condenser with automatic liquid film removal according to claim 1, characterized in that, The integrated subcooling unit (4) includes two rows of tube bundles (41) that extend radially along the housing (14) and are staggered.

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