Horizontal pipe falling film evaporation seawater desalination device

Abstract

The invention provides a horizontal tube falling film evaporation seawater desalination device, which relates to the technical field of seawater desalination, and comprises a plurality of single-effect evaporators connected in series, a first steam channel is arranged on a first side of a vaporization cavity of each single-effect evaporator, a second steam channel is arranged on a second side of the vaporization cavity, and a liquid distributor is arranged on the upper part of the inner side of the vaporization cavity. A plurality of layers of liquid discharging heat exchange pipes and special-shaped heat exchange pipes are arranged below the liquid distributor, the first ends and the second ends of the liquid discharging heat exchange pipes communicate with the first steam channel and the second steam channel correspondingly, and the first ends and the second ends of the special-shaped heat exchange pipes communicate with the first steam channel and the second steam channel correspondingly. The liquid discharge heat exchange pipe is arranged on the upper portion of the vaporization cavity, liquefied gas discharge is accelerated, gas flow is increased, meanwhile, the special-shaped heat exchange pipe is arranged on the lower portion of the vaporization cavity, the upper portion of the special-shaped heat exchange pipe is of a slope structure, accumulation of salt dirt on the pipe wall can be reduced through seawater scouring, and therefore the heat exchange effect is improved on the basis of reducing dirt. And the overall heat exchange efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of seawater desalination, and in particular to a horizontal tube falling film evaporation seawater desalination device. Background Art

[0002] Although the earth's surface is covered with a lot of water, most of it is salt water resources such as seawater, and only a small amount of fresh water is available for human drinking. Against the background of increasingly scarce fresh water resources, seawater desalination technology has emerged, aiming to remove salt from seawater and produce fresh water resources that can be directly used by humans. This technology is of great significance to alleviating the global water shortage, especially in coastal and island areas. According to the separation process, seawater desalination has distillation, membrane, crystallization and solvent extraction, and different desalination equipment has been derived. Among them, the horizontal tube falling film evaporator has been widely used due to its high heat transfer efficiency, low energy consumption and flexible operation.

[0003] The horizontal tube falling film evaporator is composed of multiple single-effect evaporators, namely: the steam generated by the first effect evaporator is used as heating steam and introduced into the second effect evaporator; the evaporation temperature of seawater in the second effect evaporator is reduced by reducing the pressure to form hot steam slightly lower than that of the first effect evaporator; and the hot steam of the second effect is further introduced into the third effect, and so on. The horizontal tube falling film evaporator has high requirements for the stability and uniformity of liquid distribution during application, and because the arranged heat exchange tubes are long and the number of spatial arrangements is large, the heat exchange characteristics at different positions vary greatly. During operation, there may be a large amount of liquefied water inside a part of the heat exchange tubes, which affects the heat exchange efficiency; and a small amount of brine outside another part of the heat exchange tubes, which is easy to form salt scale and has low thermal utilization. Therefore, the present invention provides a horizontal tube falling film evaporation seawater desalination device to solve the above problems. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a horizontal tube falling film evaporation seawater desalination device, in which a liquid discharge heat exchange tube is adopted at the upper part of the vaporization chamber, and a combined structure including two baffles and a movable plug is arranged in the liquid discharge heat exchange tube to accelerate the removal of the accumulated liquid of the liquefied gas and increase the subsequent steam wall contact heat exchange area. At the same time, a special-shaped heat exchange tube is adopted in the lower part of the vaporization chamber. The upper part of the special-shaped heat exchange tube is a slope structure, which can reduce the accumulation of salt scale on the tube wall through seawater scouring, thereby reducing the scale and improving the overall heat exchange efficiency.

[0005] The technical solution adopted by the present invention is a horizontal tube falling film evaporation seawater desalination device, which includes a plurality of single-effect evaporators, each of which includes a vaporization chamber, a first steam channel is provided on the first side of the vaporization chamber, and a first air inlet is provided on the top of the first steam channel, a second steam channel is provided on the second side of the vaporization chamber, and a second air inlet is provided on the top of the second steam channel, a first air outlet, an air extraction hole and a second air outlet are provided on the top of the vaporization chamber, and a liquid distributor is provided on the inner upper part of the vaporization chamber, and the distributor A liquid discharge heat exchange tube and a special-shaped heat exchange tube are arranged below the liquid collector; the liquid discharge heat exchange tube includes multiple layers of liquid discharge heat exchange tubes, and each layer of the liquid discharge heat exchange tubes is evenly provided with multiple liquid discharge heat exchange tubes, each of the liquid discharge heat exchange tubes is a hollow heat exchange tube shell, and each of the liquid discharge heat exchange tubes includes a heat exchange tube shell, a first baffle, a second baffle and a movable plug, the first end of the heat exchange tube shell is connected to the first steam channel, and the second end of the heat exchange tube shell is connected to the second steam channel, the first baffle and the second baffle are both truncated discs, and the heat exchange tube The first baffle is provided at the first end of the inner side of the shell, the second baffle is provided at the second end of the inner side of the heat exchange tube shell, the movable plug is provided in the heat exchange tube shell and is located between the first baffle and the second baffle, and the movable plug can move between the first baffle and the second baffle; the special-shaped heat exchange tube includes multiple layers of special-shaped heat exchange tubes, and each layer of the special-shaped heat exchange tube is evenly provided with multiple special-shaped heat exchange tubes, the special-shaped heat exchange tube is a hollow pipe, the upper part of the cross section of the special-shaped heat exchange tube is an isosceles triangle shape, and the lower part of the cross section of the special-shaped heat exchange tube is a semicircular shape The first end of the special-shaped heat exchange tube is connected to the first steam channel, and the second end of the special-shaped heat exchange tube is connected to the second steam channel; the multiple single-effect evaporators are connected in series, and the first air outlet and the second air outlet on the previous single-effect evaporator are respectively connected to the first air inlet and the second air inlet on the next single-effect evaporator, until the first air outlet and the second air outlet on the last single-effect evaporator are connected to the condenser, and the exhaust hole on each single-effect evaporator is connected to the exhaust device, and the multiple single-effect evaporators work together to desalinate seawater.

[0006] Preferably, the liquid distributor is a hollow structure, and includes a water inlet, a water storage chamber and a plurality of water outlet chambers, the water storage chamber is a rectangular cavity, and the water inlet is arranged at the top of the water storage chamber, the plurality of water outlet chambers are arranged at the bottom of the water storage chamber, and the water outlet chamber is a long strip cavity, each of the water outlet chambers is provided with a water outlet at the bottom, and a plurality of drainage heat exchange tubes and special-shaped heat exchange tubes are sequentially arranged below each water outlet chamber.

[0007] Furthermore, the first baffle and the second baffle have the same structure, and an angle between a line between a first end point of the first baffle and a center point of the first baffle and a line between a second end point of the first baffle and a center point of the first baffle is 120° to 150°.

[0008] Preferably, the distance from the first baffle to the first end of the heat exchange tube shell is equal to the distance from the second baffle to the second end of the heat exchange tube shell, and the distance between the first baffle and the second baffle is equal to 1 / 5 to 1 / 3 of the length of the heat exchange tube shell.

[0009] Preferably, the distance between the first baffle and the second baffle in the upper layer of the liquid discharge heat exchange tube is greater than the distance between the first baffle and the second baffle in the lower layer of the liquid discharge heat exchange tube.

[0010] Furthermore, the included angle of the isosceles triangle on the upper part of the special-shaped heat exchange tube is 60° to 90°.

[0011] The characteristics and beneficial effects of the present invention are:

[0012] 1. The horizontal tube falling film evaporation seawater desalination device provided by the present invention adopts a liquid discharge heat exchange tube at the bottom of the vaporization chamber, and a first baffle, a second baffle and a movable plug are arranged in the liquid discharge heat exchange tube. The movable plug moves between the first baffle and the second baffle, which can accelerate the removal of accumulated liquid of liquefied gas, increase gas flow, and improve heat exchange efficiency.

[0013] 2. In the horizontal tube falling film evaporation seawater desalination device provided by the present invention, the drainage effect intensity can be adjusted by the distance between two baffles in the drainage heat exchange tube. That is, for the drainage heat exchange tube of the upper layer, the steam liquefaction speed in the tube is relatively large, the formed liquid level is high, and it is easy to contact the baffle to form a sealing structure. The distance between the baffles can be appropriately increased to increase the drainage range. For the drainage heat exchange tube at the lower layer, the distance between the baffles can be reduced, which is conducive to forming a sealing structure.

[0014] 3. The horizontal tube falling film evaporation seawater desalination device provided by the present invention adopts a special-shaped heat exchange tube at the bottom of the vaporization chamber. The upper part of the special-shaped heat exchange tube is a slope structure. The speed of seawater decreases relatively little when it contacts the top of the slope. The slope surface is continuously washed during the downward movement along the slope, which can avoid the formation of salt scale and avoid the problem that salt scale on the top of the heat exchange tube produced by traditional heat exchange tubes is easily accumulated, and the accumulated salt scale will affect the heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a front view of the single-effect evaporator of the present invention;

[0016] Figure 2 It is a left side view of the single-effect evaporator of the present invention;

[0017] Figure 3 is a top view of a single-effect evaporator of the present invention;

[0018] Figure 4 is a front view of the liquid distributor of the present invention;

[0019] Figure 5 It is a left side view of the liquid distributor of the present invention;

[0020] Figure 6 is a top view of the liquid distributor of the present invention;

[0021] Figure 7 is a cross-sectional view of the liquid discharge heat exchange tube of the present invention;

[0022] Figure 8 is a cross-sectional view of the liquid discharge heat exchange tube of the present invention;

[0023] Fig. 9 is a structural diagram of the first baffle of the present invention;

[0024] Fig.10 is a cross-sectional view of the special-shaped heat exchange tube of the present invention;

[0025] Fig.11 is a schematic diagram of the salt water evaporation process of the present invention;

[0026] Fig.12 It is a schematic diagram of the hot steam liquefaction process of the present invention;

[0027] Fig.13 This is a schematic diagram of the working process of the conventional common heat exchange tube of the present invention;

[0028] Fig.14 This is a schematic diagram of the working process of the liquid discharge heat exchange tube of the present invention;

[0029] Fig.15 It is a schematic diagram of the external flow characteristics of the conventional ordinary heat exchange tube of the present invention;

[0030] Fig.16 It is a schematic diagram of the external smoothness characteristics of the special-shaped heat exchange tube of the present invention.

[0031] Main reference numerals:

[0032] First steam channel 1; first air inlet 11; vaporization chamber 2; first air outlet 22; air extraction hole 21; second air outlet 23; second steam channel 3; second air inlet 31; liquid distributor 4; water inlet 41; water storage chamber 42; water outlet chamber 43; liquid discharge heat exchange tube 5; heat exchange tube shell 51; first baffle 52; second baffle 53; movable plug 54; special-shaped heat exchange tube 6. DETAILED DESCRIPTION

[0033] In order to fully describe the technical content, structural features, objectives and effects of the present invention, the following will be described in detail with reference to the accompanying drawings.

[0034] A horizontal tube falling film evaporation seawater desalination device according to the present invention, such as Figure 1 to Figure 3 As shown, it includes multiple single-effect evaporators, which are connected in series, and the first air outlet 22 and the second air outlet 23 on the previous effect evaporator are respectively connected with the first air inlet 11 and the second air inlet 31 on the next effect evaporator, until the first air outlet 22 and the second air outlet 23 on the last effect evaporator are connected with the condenser, and the exhaust hole 21 on each effect evaporator is connected with the exhaust device, and the multiple single-effect evaporators together form a multi-effect working mechanism to desalinate seawater.

[0035] like Figure 1 to Figure 3 As shown, the main structure of the single-effect evaporator is a vaporization chamber 2, a first steam channel 1 is provided on the first side of the vaporization chamber 2, and a first air inlet 11 is provided on the top of the first steam channel 1, a second steam channel 3 is provided on the second side of the vaporization chamber 2, and a second air inlet 31 is provided on the top of the second steam channel 3, a first air outlet 22, an air suction hole 21 and a second air outlet 23 are provided on the top of the vaporization chamber 2, and a liquid distributor 4 is provided on the inner upper part of the vaporization chamber 2, and a liquid discharge heat exchange pipe 5 and a special-shaped heat exchange pipe 6 are provided below the liquid distributor 4.

[0036] like Figures 4 to 6 As shown, the liquid distributor 4 is a hollow structure, and includes a water inlet 41, a water storage chamber 42 and a plurality of water outlet chambers 43. The water storage chamber 42 is a rectangular cavity, and the water inlet 41 is arranged at the top of the water storage chamber 42. The plurality of water outlet chambers 43 are arranged at the bottom of the water storage chamber 42, and the water outlet chamber 43 is a long strip cavity. A water outlet is arranged at the bottom of each water outlet chamber 43, and a plurality of liquid discharge heat exchange tubes 5 and special-shaped heat exchange tubes 6 are arranged in sequence below each water outlet chamber 43.

[0037] like Figure 7 to Figure 9 As shown, the liquid discharge heat exchange tube 5 includes multiple layers of liquid discharge heat exchange tubes 5, and each layer of liquid discharge heat exchange tubes 5 is evenly distributed with multiple liquid discharge heat exchange tubes 5, each liquid discharge heat exchange tube 5 is a hollow heat exchange tube shell, and each liquid discharge heat exchange tube 5 includes a heat exchange tube shell 51, a first baffle 52, a second baffle 53 and a movable plug 54, the first end of the heat exchange tube shell 51 is connected to the first steam channel 1, and the second end of the heat exchange tube shell 51 is connected to the second steam channel 3, the first baffle 52 and the second baffle 53 are both truncated circular pieces, and the first end of the inner side of the heat exchange tube shell 51 is provided with a first baffle 52, and the second end of the inner side of the heat exchange tube shell 51 is provided with a second baffle 53, the movable plug 54 is provided in the heat exchange tube shell 51 and is located between the first baffle 52 and the second baffle 53, and the movable plug 54 can move between the first baffle 52 and the second baffle 53.

[0038] like Figure 7 As shown, the distance from the first baffle 52 to the first end of the heat exchange tube shell 51 is equal to the distance from the second baffle 53 to the second end of the heat exchange tube shell 51, and the distance between the first baffle 52 and the second baffle 53 is equal to 1 / 5 to 1 / 3 of the length of the heat exchange tube shell 51. The distance between the first baffle 52 and the second baffle 53 in the upper layer of the liquid discharge heat exchange tube 5 is greater than the distance between the first baffle 52 and the second baffle 53 in the lower layer of the liquid discharge heat exchange tube 5.

[0039] like Fig. 9 As shown, the first baffle 52 and the second baffle 53 have the same structure, and the angle between the line between the first end point of the first baffle 52 and the center of the first baffle 52 and the line between the second end point of the first baffle 52 and the center of the first baffle 52 is 120° to 150°.

[0040] like Fig.10 As shown, the special-shaped heat exchange tube 6 includes multiple layers of special-shaped heat exchange tubes 6, and each layer of special-shaped heat exchange tubes 6 is provided with multiple special-shaped heat exchange tubes 6, the special-shaped heat exchange tube 6 is a hollow pipe, the upper part of the cross section of the special-shaped heat exchange tube 6 is an isosceles triangle shape, the angle of the isosceles triangle in the upper part of the special-shaped heat exchange tube 6 is 60° to 90°, and the lower part of the cross section of the special-shaped heat exchange tube 6 is a semicircular shape, the first end of the special-shaped heat exchange tube 6 is connected to the first steam channel 1, and the second end of the special-shaped heat exchange tube 6 is connected to the second steam channel 3.

[0041] The specific working process of the present invention is as follows:

[0042] like Figures 1 to 10 As shown, a horizontal tube falling film evaporation seawater desalination device of the present invention includes a plurality of single-effect evaporators. During operation, a plurality of single-effect evaporators are connected in series to form a multi-effect working mode, that is, external heating steam enters the first steam channel 1 through the first air inlet 11 of the first-effect evaporator, and enters the second steam channel 3 through the second air inlet 31. The first steam channel 1 and the second steam channel 3 are connected through the heat exchange pipe in the vaporization chamber 2. The first air outlet 22 and the second air outlet 23 on the first-effect evaporator are respectively connected with the first air inlet 11 and the second air inlet 31 on the second-effect evaporator, and the other evaporators are connected in sequence until the first air outlet 22 and the second air outlet 23 on the last-effect evaporator of the last evaporator are connected with the condenser. At the same time, the air extraction hole 21 of each effect evaporator is connected to the air extraction device, and the evaporation temperature of the brine is reduced by the low-pressure environment formed by the air extraction. The pressure in the vaporization chamber 2 of each effect evaporator is lower than the pressure in the vaporization chamber 2 of the previous effect evaporator, so that the steam generated in the previous effect can be used to heat the seawater of the next effect and complete the vaporization of the seawater. Seawater is introduced into the water inlet of each effect liquid distributor.

[0043] The desalination device uses heat exchange tubes to complete the heat exchange of materials inside and outside the tubes, thereby realizing two phase change processes: liquefaction of hot steam into fresh water and evaporation of seawater. The heat exchange tubes include a discharge heat exchange tube 5 arranged at the upper part of the vaporization chamber 2 and a special-shaped heat exchange tube 6 arranged at the lower part. Fig.11 S is salt water, S + For concentrated salt water, such as Fig.11 As shown, the brine passes through the liquid distributor 4 and reaches the discharge heat exchange tube 5 downward, forming a liquid film on the outer wall of the tube and exchanging heat with the hot steam in the tube. The temperature gradually rises and vaporization is completed. Therefore, the mass of the brine gradually decreases during the downward movement, and the generated gas enters the next effect device through the first outlet 22 and the second outlet 23, and the remaining concentrated brine falls into the bottom of the vaporization chamber. At the same time, Fig.12 As shown, Fig.12 In the figure, L is liquefied fresh water, and F is fresh water. The hot steam introduced from the previous effect enters the first steam channel 1 and the second steam channel 3 through the first air inlet hole 11 and the second air inlet hole 31, and further fills the discharge heat exchange tube 5 and the special-shaped heat exchange tube 6. The hot steam exchanges heat with the brine outside the tube through the wall surface, and liquefies to form fresh water after the temperature is reduced. The fresh water is collected at the bottom of the first steam channel 1 and the second steam channel 3.

[0044] The heat transfer process in the horizontal tube falling film evaporation desalination device determines the efficiency of the system. Fig.11 As shown in the figure, it can be seen that when seawater moves downward from the replenisher, it completes vaporization by absorbing heat, the quality of the brine gradually decreases, and the salt concentration increases. Therefore, the heat exchange capacity of the upper part of the vaporization chamber is large, and a large amount of hot steam inside the heat exchange tube is liquefied and stored at the bottom of the heat exchange tube to form a liquid surface, which affects the heat exchange; while the brine flow rate in the lower part of the vaporization chamber is small, the salt concentration is high, and it is easy to dry up on the outside of the heat exchange tube, thereby generating salt scale, affecting the heat exchange and accelerating corrosion.

[0045] like Fig.13 As shown in the figure, Y is the liquid level. A certain liquid level distribution will be formed inside the traditional round tube heat exchange tube. When the liquid level is high, it will affect the heat exchange of the tube wall. To solve this problem, the present invention adopts a liquid discharge heat exchanger 5 on the upper part of the gasification chamber 2. Its working principle is as follows Fig.14As shown in the figure, D is the direction of movement. When the amount of water generated during the liquefaction process is greater than the amount of water discharged, the liquid level gradually rises. When the liquid level on the right side approaches the first baffle 52, a closed space will be formed, which will seal a part of the hot steam. As the enclosed hot steam is liquefied, the pressure in the closed space decreases, and the movable plug 54 moves to the right under the action of pressure. The rightward movement of the movable plug 54 will bring the following benefits: 1) increase the height of the liquid level on the right side, which is beneficial to the discharge of liquid; 2) reduce the height of the liquid level on the left side, and improve the heat exchange efficiency on the left side; 3) reduce the air pressure in the space enclosed by the left baffle and the movable plug, which is beneficial to hot steam filling. As the right side space and drainage efficiency increase, the drainage flow is greater than the liquefaction amount, and the liquid level gradually drops below the baffle; as the left side space of the movable plug 54 increases, the steam liquefaction amount is greater than the drainage amount, the liquid level gradually rises and reaches the second baffle 53 to form a closed space, and as the steam in the closed space liquefies, its pressure decreases, causing the movable plug 54 to move to the left; similarly, the movable plug 54 moving to the left can accelerate the drainage on the left side, accelerate the air intake on the right side and reduce the liquid level on the right side. As the drainage speed on the left side increases, the drainage heat exchange pipe 5 returns to the initial state, and the cycle continues.

[0046] The intensity of the liquid discharge effect in the liquid discharge heat exchange tube 5 can be adjusted by the distance between the first baffle 52 and the second baffle 53. For the liquid discharge heat exchange tube 5 at the top, the steam liquefaction speed in the tube is relatively high, and the formed liquid level is at a high position, which is easy to contact the baffle to form a sealing structure. The distance between the baffles can be appropriately increased to increase the liquid discharge range; for the liquid discharge heat exchange tube at a lower position, the distance between the baffles can be reduced, which is conducive to forming a sealing structure.

[0047] The liquid film and flow characteristics formed by seawater on the outside of the heat exchange tube are related to the shape of the heat exchange tube. Fig.15 Y is the liquid level, G is the salt scale, Fig.15 As shown, the shape of the liquid film on the outside of a traditional circular heat exchange tube is shown. The seawater is subjected to an upward force at the top of the circular tube, and its movement speed is reduced. In the process of flowing downward along the tube wall, the speed gradually increases. When it reaches the lower part of the heat exchange tube, it is affected by the viscosity of the tube wall and the flow speed is reduced again. For the heat exchange tube at the bottom of the vaporization chamber 2, the liquid film is thin and dry wall phenomenon is prone to occur. At this time, salt scale is easy to form on the top of the circular heat exchange tube. Since the fluid speed at this position is relatively low, the impact of the fluid on the salt scale is also small, and the salt scale is easy to accumulate. The accumulated salt scale will affect the heat exchange. The present invention uses a special-shaped heat exchange tube at the bottom of the vaporization chamber. The top of the heat exchange tube is a slope structure. The brine has a relatively small speed reduction when it contacts the top of the slope. The slope surface is continuously flushed during the downward movement along the slope, which can avoid the formation of salt scale. Fig.16 As shown, Y is the liquid level.

[0048] The above embodiments are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A horizontal tube falling film evaporation seawater desalination device, characterized in that: It includes a plurality of single-effect evaporators, each of which includes a vaporization chamber, a first steam channel is provided on a first side of the vaporization chamber, and a first air inlet is provided on the top of the first steam channel, a second steam channel is provided on a second side of the vaporization chamber, and a second air inlet is provided on the top of the second steam channel, a first air outlet, an air extraction hole and a second air outlet are provided on the top of the vaporization chamber, a liquid distributor is provided on the inner upper part of the vaporization chamber, and a liquid discharge heat exchange pipe and a special-shaped heat exchange pipe are provided below the liquid distributor; The liquid discharge heat exchange tube comprises multiple layers of liquid discharge heat exchange tubes, and each layer of the liquid discharge heat exchange tubes is evenly provided with multiple liquid discharge heat exchange tubes, each of the liquid discharge heat exchange tubes is a hollow heat exchange tube shell, and each of the liquid discharge heat exchange tubes comprises a heat exchange tube shell, a first baffle, a second baffle and a movable plug, the first end of the heat exchange tube shell is connected to the first steam channel, and the second end of the heat exchange tube shell is connected to the second steam channel, the first baffle and the second baffle are both circular pieces with truncations, and the first end of the inner side of the heat exchange tube shell is provided with the first baffle, and the second end of the inner side of the heat exchange tube shell is provided with the second baffle, the movable plug is provided in the heat exchange tube shell and is located between the first baffle and the second baffle, and the movable plug can move between the first baffle and the second baffle; The special-shaped heat exchange tube includes multiple layers of special-shaped heat exchange tubes, and each layer of the special-shaped heat exchange tubes is provided with multiple special-shaped heat exchange tubes, the special-shaped heat exchange tube is a hollow pipe, the upper part of the cross section of the special-shaped heat exchange tube is an isosceles triangle shape, and the lower part of the cross section of the special-shaped heat exchange tube is a semicircular shape, the first end of the special-shaped heat exchange tube is connected to the first steam channel, and the second end of the special-shaped heat exchange tube is connected to the second steam channel; The multiple single-effect evaporators are connected in series, and the first air outlet and the second air outlet on the previous single-effect evaporator are respectively connected with the first air inlet and the second air inlet on the next single-effect evaporator, until the first air outlet and the second air outlet on the last single-effect evaporator are connected with the condenser, and the exhaust hole on each single-effect evaporator is connected with the exhaust device, and the multiple single-effect evaporators work together to desalinate seawater.

2. The horizontal tube falling film evaporation seawater desalination device according to claim 1, characterized in that: The liquid distributor is a hollow structure, and includes a water inlet, a water storage chamber and a plurality of water outlet chambers. The water storage chamber is a rectangular cavity, and the water inlet is arranged at the top of the water storage chamber. The plurality of water outlet chambers are all arranged at the bottom of the water storage chamber, and the water outlet chamber is a long strip cavity. A water outlet is provided at the bottom of each water outlet chamber, and a plurality of drainage heat exchange tubes and special-shaped heat exchange tubes are sequentially provided below each water outlet chamber.

3. The horizontal tube falling film evaporation seawater desalination device according to claim 1, characterized in that: The first baffle and the second baffle have the same structure, and an angle between a line between a first end point of the first baffle and a center point of the first baffle and a line between a second end point of the first baffle and a center point of the first baffle is 120° to 150°.

4. The horizontal tube falling film evaporation seawater desalination device according to claim 3 is characterized in that: The distance from the first baffle to the first end of the heat exchange tube shell is equal to the distance from the second baffle to the second end of the heat exchange tube shell, and the distance between the first baffle and the second baffle is equal to 1 / 5 to 1 / 3 of the length of the heat exchange tube shell.

5. The horizontal tube falling film evaporation seawater desalination device according to claim 4, characterized in that: The distance between the first baffle and the second baffle in the upper layer of the liquid discharge heat exchange tube is greater than the distance between the first baffle and the second baffle in the lower layer of the liquid discharge heat exchange tube.

6. The horizontal tube falling film evaporation seawater desalination device according to claim 1, characterized in that: The included angle of the isosceles triangle on the upper part of the special-shaped heat exchange tube is 60° to 90°.

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