Efficient heat exchanger for realizing shell-side medium falling film evaporation

Abstract

The invention relates to the technical field of heat exchangers, in particular to a shell side medium falling film evaporation efficient heat exchanger which comprises a shell, a front end pipe box body structure and a rear end pipe box body structure are arranged at the two ends of the shell respectively, and a pipe bundle composed of heat exchange pipes is arranged in the shell. The tube bundle located in the shell is provided with a film forming distribution assembly capable of conducting film forming distribution on all the heat exchange tubes at the same time. The film-forming distribution assembly comprises a film-forming distribution sliding table, film-forming hole channels used for being arranged on all the heat exchange pipes in a sliding and sleeving mode are formed in the film-forming distribution sliding table in a penetrating mode, and a liquid distribution cavity of the film-forming distribution sliding table achieves uniform distribution of media in all the film-forming hole channels and is matched with gaps between the film-forming hole channels and the heat exchange pipes to ensure that the media form a liquid film with the uniform thickness. The reciprocating displacement driving structure drives the sliding table to reciprocate along the trend of the heat exchange tube, so that no-missing film distribution of the whole tube body is realized, the problems of no local film and non-uniform liquid film are solved, and the utilization rate of the heat exchange tube and the overall heat exchange efficiency are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger technology, and more specifically to a high-efficiency heat exchanger that realizes shell-side medium falling film evaporation. Background Technology

[0002] A falling film evaporator heat exchanger is a highly efficient shell-and-tube heat exchange device. Its core feature is that the material forms a uniform liquid film on the surface of the heat exchange tubes and flows there, while simultaneously exchanging heat with the heating medium on the other side to achieve evaporation and concentration. It is widely used in industrial fields such as food, pharmaceuticals, chemicals, and seawater desalination.

[0003] A novel liquid distributor structure and a falling film evaporator high-efficiency heat exchanger are disclosed in publication number CN217988377U. The novel liquid distributor structure includes a liquid distributor body arranged in a cage shape with multiple circular holes on its surface; multiple heat exchange tubes are disposed within the liquid distributor body.

[0004] A heat exchanger for acetic acid production based on horizontal tube falling film evaporation technology, disclosed in CN119334167A, includes a tank body. A connecting ring a is fixedly sleeved on the tank body. A connecting ring b is fixedly connected to the connecting ring a by bolts and nuts. A tank tail is fixedly connected inside the connecting ring b. Two support frames are fixedly installed on the tank tail. A fixing block is set inside the tank tail. Several arc-shaped grooves are opened on the fixing block.

[0005] Traditional shell-side medium falling film evaporative heat exchangers have many technical pain points in practical applications, which restrict heat exchange efficiency and equipment stability. Traditional liquid distribution structures make it difficult to achieve uniform distribution of the medium on the surface of each heat exchange tube, which easily leads to inconsistent liquid film thickness and local heat exchange tubes without liquid film coverage, resulting in low heat exchange tube utilization and poor overall heat exchange efficiency. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] The purpose of this invention is to provide a high-efficiency heat exchanger for shell-side medium falling film evaporation in order to solve the above-mentioned problems.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] The present invention provides a high-efficiency heat exchanger for shell-side medium falling film evaporation, comprising a shell, a front tube box structure and a rear tube box structure respectively provided at both ends of the shell, a tube bundle composed of various heat exchange tubes provided inside the shell, and a film distribution component capable of simultaneously distributing film on each heat exchange tube on the tube bundle located inside the shell.

[0011] The film-forming distribution assembly includes a film-forming distribution slide, on which film-forming channels are slidably opened for sliding on each heat exchange tube. Each film-forming channel is provided with a liquid distribution chamber that can communicate with each other. The housing is provided with a liquid delivery pipe structure that can deliver liquid to the liquid distribution chamber. The housing is provided with a reciprocating displacement drive structure that can drive the film-forming distribution slide to move along the direction of the heat exchange tube.

[0012] Furthermore, the reciprocating drive structure includes several lead screws, which are rotatably disposed inside the housing. The film-forming distribution slide has threaded holes that cooperate with the lead screws, and one end of the lead screws extends out of the housing and is driven to rotate by a servo motor.

[0013] Furthermore, the lead screw has two parallel distributions, which are symmetrically distributed on both sides of the tube bundle. Two guide rods are symmetrically distributed on both sides of the lead screw with the guide rods as the center. A guide hole for sliding through the guide rods is provided on the film distribution slide.

[0014] Furthermore, the gap between the inner wall of the film-forming channel and the outer wall of the heat exchange tube is 0.1-5 mm.

[0015] Furthermore, tube bundle support plates are provided at both ends of the tube bundle, and a telescopic sleeve is provided on the outside of the lead screw located between the film distribution slide and the two tube bundle support plates.

[0016] Furthermore, the liquid delivery pipe structure includes a bendable liquid guide pipe, and an accordion cover is fitted on the outside of the liquid guide pipe to support its bending. One end of the liquid guide pipe is connected to the film distribution slide and communicates with the liquid distribution chamber, and the other end of the liquid guide pipe extends out of the shell and is connected to an inlet pipe.

[0017] Furthermore, the front-end tube box structure includes a front tube box cover plate connected to the shell, the front tube box cover plate is provided with a cylindrical front tube box inlet, and an elongated elliptical inlet transition section is provided between the front tube box inlet and the front tube box cover plate.

[0018] Furthermore, the rear pipe box structure includes a rear pipe box cover plate connected to the shell, and the rear pipe box cover plate is provided with a cylindrical rear pipe box outlet pipe.

[0019] Furthermore, the housing is provided with an expansion joint that can balance the difference in expansion between the housing and the tube bundle and reduce axial stress.

[0020] Furthermore, the lower side of the shell is provided with a shell-side liquid reservoir, the bottom of the shell-side liquid reservoir is provided with a liquid outlet and an anti-vortex device is provided at the liquid outlet, and the shell-side liquid reservoir is provided with a plurality of liquid level gauge ports along the vertical direction.

[0021] (III) Beneficial Effects

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. The liquid distribution chamber of the film-forming distribution slide achieves uniform distribution of the medium in each film-forming channel. Combined with the gap between the film-forming channel and the heat exchange tube, it ensures that the medium forms a liquid film of uniform thickness. The reciprocating drive structure drives the slide to move back and forth along the heat exchange tube, achieving film distribution without any omissions in the entire tube, solving the problems of no film in some areas and uneven liquid film, and significantly improving the utilization rate of the heat exchange tube and the overall heat exchange efficiency.

[0024] 2. The elongated elliptical inlet transition section of the front tube box structure smoothly guides the tube-side medium from the cylindrical inlet to the heat exchange area, covering all heat exchange tubes and avoiding sudden changes in flow velocity and uneven distribution. The circular outlet pipe at the rear end slows down the medium flow velocity, prolongs the heat exchange time, and further optimizes the heat exchange effect.

[0025] 3. The telescopic sleeve on the outside of the lead screw extends and retracts synchronously with the slide table, effectively isolating the medium on the shell side, preventing the transmission components from being corroded, and extending their service life. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the main structure of the present invention;

[0028] Figure 2 This is the present invention. Figure 1 A schematic diagram of the left-side view structure;

[0029] Figure 3 This is the present invention. Figure 1 A schematic diagram of the three-dimensional structure in the first direction;

[0030] Figure 4 This is the present invention. Figure 1 A schematic diagram of the AA cross-sectional structure;

[0031] Figure 5 This is the present invention. Figure 2 A schematic diagram of the BB cross-sectional structure;

[0032] Figure 6 This is the present invention. Figure 5 A magnified schematic diagram of the structure at point C;

[0033] Figure 7 This is a schematic diagram of the film distribution component and the tube bundle of the present invention.

[0034] Figure 8 This is the present invention. Figure 7 A magnified schematic diagram of the structure at point D;

[0035] Figure 9 This is a schematic cross-sectional view of the heat exchange tube and film distribution slide of the present invention.

[0036] Figure 10 This is the present invention. Figure 1 A schematic diagram of the second-direction three-dimensional structure.

[0037] The reference numerals in the attached drawings are explained as follows: 1. Shell; 101. Liquid outlet pipe; 102. Gas outlet pipe; 2. Front-end pipe box structure; 201. Front-end pipe box inlet; 202. Inlet transition section; 203. Front-end pipe box exhaust pipe; 204. Front-end pipe box drain pipe; 205. Front pipe box cover plate; 206. Inner nest; 207. Sealing gasket; 3. Rear-end pipe box structure; 301. Rear pipe box cover plate; 302. Rear-end pipe box outlet pipe; 4. Film distribution group Components; 401, Film-forming distribution slide; 402, Lead screw; 403, Liquid distribution chamber; 404, Telescopic sleeve; 405, Guide rod; 406, Film-forming channel; 407, Servo motor; 5, Liquid delivery pipe structure; 501, Inlet pipe; 502, Liquid guide pipe; 6, Shell-side liquid reservoir; 601, Liquid level gauge port; 602, Anti-vortex device; 7, Top pressure gauge port; 8, Top vent; 9, Expansion joint; 10, Tube bundle; 11, Tube bundle support plate; 1101, Outer nest. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0039] See Figures 1-10As shown, this invention provides a high-efficiency heat exchanger for shell-side medium falling film evaporation. Its overall structural design revolves around the technical concept of high-efficiency heat exchange and simultaneous film distribution across the entire tube body. Specifically, it includes a shell 1, whose cross-sectional shape can be rectangular or circular. The shell 1 has a front tube box structure 2 and a rear tube box structure 3 at its two ends, respectively, for guiding the inlet and outlet of the tube-side medium. Inside the shell 1 is a tube bundle 10 composed of several heat exchange tubes. To provide stable support for the tube bundle 10, tube bundle support plates 11 are provided at both ends. Simultaneously, the tube bundle 10 inside the shell 1 is equipped with a film distribution component 4 capable of simultaneously and uniformly distributing the film across each heat exchange tube, ensuring the heat exchange effect of the shell-side medium. In addition, the upper side of the shell 1 is provided with a gas outlet pipe 102, a top pressure gauge port 7, and a top exhaust port 8, respectively for discharging evaporated gas, monitoring the internal pressure, and discharging redundant gas. In practical applications, according to temperature monitoring requirements, a thermocouple port for inserting a thermocouple can also be additionally provided on the shell 1.

[0040] To achieve precise film formation on each heat exchanger tube, such as Figure 1 , Figure 4 and Figure 7 As shown, the film distribution assembly 4 specifically includes a film distribution slide 401. The film distribution slide 401 has film distribution channels 406 that correspond one-to-one with each heat exchange tube, which are used to pass through each heat exchange tube. In order to ensure that the medium can be evenly distributed to each film distribution channel 406, liquid distribution chambers 403 that are interconnected are also provided between each film distribution channel 406. At the same time, the housing 1 is equipped with a liquid delivery pipe structure 5 that can stably deliver liquid to the liquid distribution chamber 403. In order to realize the dynamic film formation of the film distribution slide 401, the housing 1 is also equipped with a reciprocating displacement drive structure that can drive it to move along the direction of the heat exchange tube.

[0041] To drive the film distribution slide 401 to move smoothly back and forth, the reciprocating drive structure adopts a screw drive design, specifically including several screws 402. The screws 402 are rotatably mounted inside the housing 1. Correspondingly, the film distribution slide 401 has threaded holes that are adapted to the screws 402. After one end of the screw 402 passes through the housing 1, it is driven to rotate by the servo motor 407, and the film distribution slide 401 moves through the threaded engagement.

[0042] In the specific configuration, there are two lead screws 402 arranged in parallel, and the two lead screws 402 are symmetrically distributed on both sides of the tube bundle 10 to ensure balanced driving force. At the same time, in order to prevent the film distribution slide 401 from deviating when it moves, there are two guide rods 405 symmetrically distributed on both sides of the lead screw 402 with the lead screw 402 as the center. The film distribution slide 401 is provided with corresponding guide holes for sliding through the guide rods 405. Precise guidance is achieved through the cooperation of the guide rods and the guide holes.

[0043] To ensure that the medium on the shell side can form a liquid film of uniform thickness that meets the heat exchange requirements on the surface of the heat exchange tube, a gap of 0.1-5mm is reserved between the inner wall of the film-forming channel 406 and the outer wall of the heat exchange tube. This gap size can be flexibly adjusted according to the medium characteristics and heat exchange requirements.

[0044] To protect the lead screw 402 from corrosion by the shell-side medium and extend its service life, a telescopic sleeve 404 is also provided on the outside of the lead screw 402 located between the film distribution slide 401 and the two tube bundle support plates 11, which can extend and retract synchronously with the movement of the film distribution slide 401.

[0045] like Figure 1 , Figure 3 and Figure 7 As shown, the liquid delivery pipe structure 5 includes a bendable liquid guide pipe 502 that can adapt to the movement of the film distribution slide 401; considering the bending stability of the liquid guide pipe 502, a bellows cover is fitted on its outer side to support and protect the bending action; one end of the liquid guide pipe 502 is fixedly connected to the film distribution slide 401 and communicates with the liquid distribution chamber 403, and the other end extends out of the shell 1 and is connected to an inlet pipe 501 for connecting the shell-side medium to be heat exchanged.

[0046] The inlet of the tubular medium is smoothly guided through the front-end tubular housing structure 2, such as... Figure 1 , Figure 2 , Figure 3 and Figure 6 As shown, the front-end tube box structure 2 includes a front tube box cover plate 205 that is sealed to the shell 1. The front tube box cover plate 205 is provided with a cylindrical front tube box inlet 201. In order to avoid sudden changes in flow rate and uneven distribution when the medium enters, an elongated elliptical inlet transition section 202 is provided between the front tube box inlet 201 and the front tube box cover plate 205. At the same time, in order to facilitate the discharge of gas and liquid in the tube medium, a front tube box exhaust pipe 203 is provided on the upper side of the inlet transition section 202, and a front tube box liquid drain pipe 204 is provided on the lower side.

[0047] After heat exchange, the tube-side medium is discharged through the rear tube housing structure 3, such as... Figure 1 , Figure 5 , Figure 6 and Figure 10As shown, the rear pipe box structure 3 includes a rear pipe box cover plate 301 connected to the housing 1. The rear pipe box cover plate 301 is provided with a cylindrical rear pipe box outlet pipe 302. In practical applications, to adapt to the exhaust and drainage requirements under different working conditions, the upper and lower sides of the rear pipe box outlet pipe 302 can also be provided with a rear pipe box exhaust pipe and a rear pipe box drainage pipe respectively. In addition, to ensure the sealing performance between the front pipe box structure 2 and the pipe bundle 10, the front pipe box cover plate 205 is provided with an inner nest 206 facing the housing 1. Correspondingly, the pipe bundle support plate 11 is provided with an outer nest 1101 that is inserted and matched with the inner nest 206. The end of the inner nest 206 is provided with a sealing gasket 207 that seals against the pipe bundle support plate 11, effectively preventing media leakage.

[0048] Considering that the housing 1 and the tube bundle 10 may have different thermal expansion due to temperature changes during equipment operation, an expansion joint 9 is also provided on the housing 1 to balance the difference in expansion between the two, reduce axial stress, and avoid equipment deformation and damage.

[0049] After the shell-side medium evaporates through the falling film, the unevaporated liquid is collected in the shell-side liquid reservoir 6 through the liquid outlet pipe 101 on the lower side of the shell 1. Figure 2 , Figure 5 As shown, the bottom of the shell-side liquid tank 6 is provided with a liquid outlet, and in order to avoid eddies when the liquid is discharged and affect the discharge stability, an anti-eddy device 602 is provided at the liquid outlet; at the same time, in order to facilitate real-time monitoring of the liquid level in the shell-side liquid tank 6, it is provided with several liquid level gauge ports 601 along the vertical direction, which can be adapted to the installation and use of liquid level gauges with different ranges.

[0050] Working principle of the invention:

[0051] The shell-side medium to be heat-exchanged enters the flexible liquid guide pipe 502 through the inlet pipe 501 of the liquid delivery pipe structure 5. Under the support and protection of the outer bellows cover, the liquid guide pipe 502 delivers the medium to the liquid distribution chamber 403 of the film distribution assembly 4. After the liquid distribution chamber 403 achieves uniform distribution of the medium in each film-forming channel 406, the medium is guided to flow to the outer wall of each heat exchange tube of the tube bundle 10 through the film-forming channels 406 on the film distribution slide 401. The gap between the film-forming channels 406 and the outer wall of the heat exchange tube ensures that the medium can form a liquid film of uniform thickness on the surface of the heat exchange tube. At the same time, the servo motor 407 drives the two symmetrically distributed lead screws 402 in the shell 1 to rotate. Under the guidance of the guide rods 405 on both sides of the lead screw 402, the film distribution slide 401 moves back and forth along the direction of the heat exchange tube, further ensuring the uniformity of the liquid film distribution on the entire tube of each heat exchange tube. The telescopic sleeve 404 on the outside of the lead screw 402 plays a protective role.

[0052] The tube-side medium enters through the front tube box inlet 201 of the front tube box structure 2, and is smoothly guided to the inside of the front tube box cover plate 205 through the elongated elliptical inlet transition section 202. Then it enters the heat exchange tubes of the tube bundle 10 and exchanges heat with the shell-side medium. After heat exchange, the tube-side medium is discharged through the rear tube box outlet pipe 302 on the rear tube box cover plate 301 of the rear tube box structure 3. The front tube box inlet 201 is cylindrical, and the inlet transition section 202 is elongated elliptical and enters the shell 1, basically covering the heat exchange tube area, so that the fluid distribution in each heat exchange tube is uniform. The rear tube box outlet pipe 302 transitions to a circle again, which slows down the flow rate of the intermediate medium and improves the heat exchange efficiency.

[0053] During the heat exchange process, the shell-side medium undergoes falling film evaporation. The generated gas is discharged through the gas outlet pipe 102 on the upper side of the shell 1, while the unevaporated liquid flows to the shell-side liquid reservoir 6 on the lower side of the shell 1. After the liquid level is monitored by the level gauge port 601, it is smoothly discharged from the bottom outlet under the action of the anti-vortex device 602. The expansion joint 9 on the shell 1 can balance the difference in expansion between the shell 1 and the tube bundle 10 and reduce axial stress. The front tube box exhaust pipe 203, the front tube box drain pipe 204, the top pressure gauge port 7, the top exhaust port 8 and other components respectively realize auxiliary functions such as exhaust, drain, and pressure monitoring. The inner nest 206 on the front tube box cover plate 205 cooperates with the outer nest 1101 and the sealing gasket 207 on the tube bundle support plate 11 to ensure the sealing performance of the equipment.

[0054] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high efficiency heat exchanger for shell side medium falling film evaporation characterized by: The application relates to a heat exchanger, which comprises a shell (1), a front-end tube box body structure (2) and a rear-end tube box body structure (3) arranged at two ends of the shell (1) respectively, a tube bundle (10) composed of heat exchange tubes arranged in the shell (1), and a film-forming distribution assembly (4) arranged on the tube bundle (10) in the shell (1) and capable of simultaneously realizing film-forming distribution of the heat exchange tubes. The film-forming distribution assembly (4) comprises a film-forming distribution sliding table (401), film-forming holes (406) are formed through the film-forming distribution sliding table (401) and arranged on the heat exchange tubes, liquid distribution chambers (403) capable of being communicated with each other are arranged between the film-forming holes (406), a liquid conveying pipe structure (5) capable of conveying liquid to the liquid distribution chambers (403) is arranged on the shell (1), and a reciprocating displacement driving structure capable of driving the film-forming distribution sliding table (401) to move along the heat exchange tube direction is arranged on the shell (1).

2. The high efficiency heat exchanger of falling film evaporation of shell side medium according to claim 1, characterized in that: The reciprocating displacement driving structure comprises a plurality of lead screws (402), the lead screws (402) are rotationally arranged in the shell (1), screw thread through holes matched with the lead screws (402) are formed through the film-forming distribution sliding table (401), and one end of the lead screw (402) penetrates through the shell (1) and is driven to rotate by a servo motor (407).

3. The high efficiency heat exchanger of falling film evaporation of shell side medium according to claim 2, characterized in that: The lead screws (402) are arranged in parallel in two numbers and symmetrically arranged on two sides of the tube bundle (10), two guide rods (405) symmetrically arranged around the lead screws (402) are arranged on the two sides of the lead screw (402), and guide sliding holes for sliding through the guide rods (405) are formed through the film-forming distribution sliding table (401).

4. The high efficiency heat exchanger of falling film evaporation of shell side medium according to claim 2, characterized in that: The gap between the inner wall of the film-forming hole (406) and the outer wall of the heat exchange tube is 0.1-5 mm.

5. The high efficiency heat exchanger of falling film evaporation of shell side medium according to claim 1, characterized in that: The tube bundle (10) is provided with tube bundle support plates (11) at two ends, and telescopic sheaths (404) are arranged on the outer sides of the lead screws (402) between the film-forming distribution sliding table (401) and the two tube bundle support plates (11).

6. The high efficiency heat exchanger of falling film evaporation of shell side medium according to claim 1, characterized in that: The liquid conveying pipe structure (5) comprises a bendable liquid guide pipe (502), an organ case capable of supporting the bending of the liquid guide pipe (502) is arranged on the outer side of the liquid guide pipe (502), one end of the liquid guide pipe (502) is connected with the film-forming distribution sliding table (401) and communicated with the liquid distribution chamber (403), and the other end of the liquid guide pipe (502) extends out of the shell (1) and connected with an inlet connecting pipe (501).

7. The high efficiency heat exchanger of falling film evaporation of shell side medium according to claim 1, characterized in that: The front-end tube box body structure (2) comprises a front tube box cover plate (205) connected with the shell (1), a front-end tube box inlet (201) in a cylindrical shape is arranged on the front tube box cover plate (205), and an inlet transition section (202) in an oblong shape is arranged between the front-end tube box inlet (201) and the front tube box cover plate (205).

8. The high efficiency heat exchanger of falling film evaporation of shell side medium according to claim 1, characterized in that: The rear-end tube box body structure (3) comprises a rear tube box cover plate (301) connected with the shell (1), and a rear-end tube box outlet connecting pipe (302) in a cylindrical shape is arranged on the rear tube box cover plate (301).

9. The high efficiency heat exchanger of falling film evaporation of shell side medium according to claim 1, characterized in that: The shell (1) is provided with an expansion joint (9) capable of balancing the expansion difference between the shell (1) and the tube bundle (10) and reducing axial stress.

10. The high efficiency heat exchanger of falling film evaporation of shell side medium according to claim 1, characterized in that: The lower side of the shell (1) is provided with a shell side liquid pocket (6), the bottom of the shell side liquid pocket (6) is provided with a liquid outlet, the liquid outlet is provided with a vortex preventer (602), and the shell side liquid pocket (6) is provided with a plurality of liquid level gauges (601) in the up-down direction.

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