Gas-liquid distribution device and falling film evaporator comprising same

Abstract

The utility model provides a gas-liquid distribution device and a falling film evaporator comprising the gas-liquid distribution device, a gas-liquid distributor and a plurality of heat exchange tubes are sequentially arranged in a cylinder body of the gas-liquid distribution device, and a plurality of gas rising tubes and a plurality of liquid distribution holes are arranged on a bottom plate of a distribution container of the gas-liquid distributor; the projection of at least one riser covers the plurality of heat exchange tubes; the projection covers the riser of the plurality of heat exchange tubes, and the projection of a plurality of side edges of the riser spans at least two heat exchange tubes. According to the gas-liquid distribution device and the falling film evaporator comprising the gas-liquid distribution device, the plurality of heat exchange tubes are covered with the gas rising tubes, so that the pressure drop of gas in the barrel is small, and stable gas pressure power is supplied to downstream equipment. By adjusting the size and distribution of the riser, the projections of the multiple side edges of the riser in the liquid flowing direction span at least two heat exchange tubes, the steam flowing resistance is further reduced, the air pressure loss is reduced, and manufacturing is convenient.

Description

Technical Field

[0001] This utility model relates to the technical field of chemical equipment, and in particular to a gas-liquid distribution device and a falling film evaporator including the gas-liquid distribution device. Background Technology

[0002] A gas-liquid distribution device (also called a gas-liquid distributor) is used to simultaneously distribute gas (gas phase) and liquid (liquid phase), and is typically installed within equipment such as falling film evaporators or absorption heat exchangers. Taking a falling film evaporator as an example, it includes a cylindrical body, inside which, from top to bottom, are a gas-liquid distribution device and a film distributor. The gas-liquid distribution device has gas pipes for gas flow and drip holes for liquid distribution. The film distributor has multiple heat exchange tubes, and typically, the film distributor and the heat exchange tubes correspond one-to-one in the upper and lower channels. A liquid inlet is located on the cylindrical body. After the liquid material enters the cylindrical body, it passes through the gas-liquid distribution device and the film distributor sequentially from top to bottom. It is evaporated in the heat exchange tubes of the film distributor, and the evaporated vapor rises and exits from the top of the cylindrical body through the gas pipes of the gas-liquid distribution device. In this process, the purpose of the gas-liquid distribution device is not only to ensure uniform gas flow through the distributor, but also to better distribute the liquid downwards and form a film, ultimately achieving good gas-liquid mass transfer or improving heat transfer efficiency.

[0003] In different applications, gas can either enter from the top of the cylinder and flow downwards to react chemically with the liquid inside; or the liquid can enter the cylinder, evaporate in the heat exchange tubes, and the evaporated gas flows upwards and exits from the top of the cylinder. In applications, vapor enters the cylinder as compressed gas from the top of the evaporator or heat exchanger, or the vapor generated inside the cylinder needs to be maintained at a certain pressure to promote the chemical reaction. However, in existing technologies, the vapor pressure often drops as it passes through the gas-liquid distribution device, resulting in significant pressure loss, which is detrimental to the chemical reaction. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the defect of large pressure loss of gas in the gas-liquid distribution device in the prior art, and to provide a gas-liquid distribution device and a falling film evaporator including the gas-liquid distribution device.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution:

[0006] A gas-liquid distribution device includes a cylindrical body, within which a gas-liquid distributor and a plurality of heat exchange tubes are sequentially arranged along the liquid flow direction.

[0007] The gas-liquid distributor includes a distribution container, and the bottom plate of the distribution container is provided with a number of gas riser pipes for gas flow and a number of liquid distribution holes for liquid dispersion and dripping.

[0008] At least one of the riser pipes has its projection along the liquid flow direction covering the plurality of heat exchange tubes; and the projection of the riser pipe covering the plurality of heat exchange tubes spans at least two of the heat exchange tubes.

[0009] In this design, the gas-liquid distribution device features several riser pipes and several liquid distribution holes on its base plate. The distributed liquid distribution holes ensure uniform liquid distribution. Building upon this uniformity, the riser pipes cover multiple heat exchange tubes, increasing the pipe opening area and minimizing resistance to the steam generated during heat exchange as it passes through the riser pipes, thus reducing pressure loss within the cylinder. Furthermore, by adjusting the size and position of the riser pipes projecting onto the multiple heat exchange tubes, at least one side of the riser pipe, along the liquid flow direction, spans at least two heat exchange tubes. This allows steam from the two or more heat exchange tubes spanned to enter the riser pipe from the side of an adjacent riser pipe, shortening the flow path and further reducing steam flow resistance and pressure loss. In short, this gas-liquid distribution device, while ensuring uniform liquid distribution, reduces gas flow resistance and pressure loss by increasing the coverage area of ​​the riser pipes and shortening the steam entry path, thereby increasing the gas pressure driving force entering downstream equipment. Furthermore, this arrangement of the riser pipes also means that the number of riser pipes will not be too large, making them easier to manufacture.

[0010] Preferably, each of the heat exchange tubes is within the projection coverage of the riser pipe along the direction of liquid flow.

[0011] In this scheme, the above settings ensure that the steam generated by each heat exchange tube can flow out from the covered riser pipe, shortening the gas flow path and thus reducing the resistance encountered by the steam.

[0012] Preferably, the gas-liquid distribution device further includes a liquid inlet pipe, the outlet section of which is located at the center of the distribution container.

[0013] Several of the riser pipes are arranged in multiple rings around the outlet pipe section. The multiple rings of riser pipes are arranged at radial intervals along the outlet pipe. Each ring of riser pipes includes multiple riser pipes arranged in a polygonal structure.

[0014] In this design, the outlet section of the inlet pipe is positioned at the center of the distribution container, allowing the liquid to flow outwards from the center, which promotes uniform liquid distribution. Several riser pipes are arranged around the outlet pipe in the aforementioned configuration, forming a multi-ring structure with a polygonal distribution. Compared to other distribution structures, this structure improves the open area ratio (the ratio of the sum of the open areas of the riser pipes to the area of ​​the base plate), preventing droplets from being blown away by the gas phase and ensuring vapor purity. Simultaneously, each riser pipe also spaces multiple liquid distribution holes, which are generally arranged in a rhomboid pattern, further contributing to the uniformity of liquid distribution.

[0015] Preferably, a guide plate is provided below the outlet pipe section along the liquid flow direction, and the outer diameter of the guide plate is larger than the inner diameter of the outlet pipe section.

[0016] In this design, the gas-liquid distribution device uses the aforementioned guide plate to buffer the flow rate of the buffer liquid and ensures uniform flow around the guide plate. The outer diameter of the guide plate is larger than the inner diameter of the outlet pipe section, guaranteeing that the liquid flowing out of the outlet pipe section is effectively buffered and does not directly flow into the distribution container from the outlet.

[0017] Preferably, the projection of the liquid distribution hole along the liquid flow direction is located between three adjacent heat exchange tubes.

[0018] In this scheme, the above settings shorten the liquid flow path, improve the liquid distribution efficiency, and enable the liquid to evaporate faster, thereby maintaining or increasing the pressure of the gas inside the cylinder.

[0019] Preferably, the gas-liquid distributor is further provided with a tube sheet below the liquid flow direction, and the tube sheet is further provided with a membrane tube that is detachably connected to the heat exchange tubes in a one-to-one correspondence; the membrane tube is used to guide the liquid dripping onto the tube sheet into the heat exchange tubes; the projection of the riser along the liquid flow direction covers multiple membrane tubes.

[0020] In this design, after the liquid drips from the distribution holes, it is guided from the tube sheet to the heat exchange tubes by the film distribution tubes. Since there is a one-to-one correspondence between the film distribution tubes and the heat exchange tubes, the projection of the riser tubes along the liquid flow direction covers multiple film distribution tubes, ensuring that the vapor evaporated from the heat exchange tubes flows through the film distribution tubes and from the covered riser tubes.

[0021] Preferably, the circumferential wall of the membrane tube has a plurality of slots, the slot walls extend into the inner cavity of the membrane tube, the angle between the tangential surface of the tube wall at the slot and the slot wall is in the range of 5° to 45°, and the length of the slot wall along the axial direction of the membrane tube is in the range of 20mm to 80mm.

[0022] In this scheme, the liquid is evenly distributed to each film-covering tube and introduced into the heat exchange tube through the multiple slots set above. The angle between the tangential surface of the tube wall at the slot and the slot wall is set in the range of 5° to 45°, which helps to balance the flow rate of the liquid entering the film-covering tube and the evaporation rate in the heat exchange tube. The flow rate is neither too fast to allow for evaporation nor too slow to result in insufficient steam, thus achieving effective distribution and improving the evaporation effect.

[0023] Preferably, the inlet of the riser pipe is inclined to the cross-section of the riser pipe, and the inclination angle of the inlet is 45°.

[0024] In this design, the inlet of the riser pipe is configured as described above to form a cut, and the cut is inclined at a 45° angle, which can increase the flow rate of gas through the riser pipe.

[0025] Preferably, the total area of ​​all the riser pipes accounts for 25% to 50% of the area of ​​the base plate.

[0026] In this scheme, the above-mentioned ratio range is used to balance the flow rates of the gas distribution and the liquid distribution, thereby achieving a balance between the gas distribution and the liquid distribution.

[0027] A falling film evaporator, the falling film evaporator comprising the gas-liquid distribution device as described above.

[0028] In this design, the falling film evaporator, through the aforementioned gas-liquid distribution device, ensures uniform liquid distribution while reducing gas flow resistance by increasing the coverage area of ​​the riser pipes and shortening the path of steam entering the riser pipes. This reduces pressure loss and increases the pressure driving force for gas entering downstream equipment. Furthermore, this arrangement of the riser pipes also minimizes their number, simplifying manufacturing.

[0029] The positive and progressive effects of this utility model are as follows: the gas-liquid distribution device and the falling film evaporator including the gas-liquid distribution device, while ensuring the uniformity of liquid distribution, reduce gas flow resistance by increasing the coverage area of ​​the riser pipe and shortening the path of steam entering the riser pipe, thereby reducing gas pressure loss and improving the gas pressure power entering the downstream equipment. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the external structure of the falling film evaporator according to Embodiment 1 of this utility model.

[0031] Figure 2 This is a top view of the falling film evaporator of Embodiment 1 of this utility model.

[0032] Figure 3 for Figure 2 A cross-sectional view along the CC direction.

[0033] Figure 4 This is a schematic diagram of the internal structure of the falling film evaporator after the cylinder body is removed, according to Embodiment 1 of this utility model.

[0034] Figure 5 for Figure 1 The cross-sectional view along the BB direction shows the bottom plate of the distribution container transparently to reveal the heat exchange tubes distributed below the bottom plate.

[0035] Figure 6 This is a schematic diagram of the gas-liquid distributor and inlet pipe of Embodiment 1 of this utility model.

[0036] Figure 7 This is a schematic diagram of the connection between the heat exchange tube and the membrane tube in Embodiment 1 of this utility model.

[0037] Figure 8 This is a top view of the membrane tube of Embodiment 1 of this utility model.

[0038] Explanation of reference numerals in the attached drawings: Falling film evaporator 10; Gas-liquid distribution device 100; Cylinder 110; Gas outlet pipe 111; Gas-liquid distributor 120; Distribution container 130; Bottom plate 131; Liquid distribution hole 132; Rising gas pipe 140; Rising gas pipe coil 141; Liquid inlet pipe 150; Outlet pipe section 151; Inlet pipe section 152; Guide plate 153; Film distributor 190; Tube sheet 160; Film distribution tube 170; Groove 171; Groove wall 172; Tangential surface 173; Angle α; Length L; Heat exchange tube 180; Liquid flow direction A. Detailed Implementation

[0039] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0040] Example 1

[0041] This embodiment provides a gas-liquid distribution device 100, which is used in a falling film evaporator 10 or an absorption heat exchanger.

[0042] like Figures 1-3 and combined Figure 5 As shown, the gas-liquid distribution device 100 includes a cylinder 110, and a gas-liquid distributor 120 and a plurality of heat exchange tubes 180 are arranged sequentially inside the cylinder 110 along the liquid flow direction A.

[0043] The gas-liquid distributor 120 includes a distribution container 130. The bottom plate 131 of the distribution container 130 is provided with a plurality of gas riser pipes 140 for gas flow and a plurality of liquid distribution holes 132 for liquid dispersion and dripping. At least one gas riser pipe 140, projected along the liquid flow direction A, covers a plurality of heat exchange tubes 180; and within the gas riser pipe 140 whose projection covers the plurality of heat exchange tubes 180, at least one side of the gas riser pipe 140, projected along the liquid flow direction A, spans at least two heat exchange tubes 180.

[0044] Specifically, in this embodiment, the cylinder 110 is also the cylinder 110 of the falling film evaporator 10, and the top of the cylinder 110 is provided with a gas outlet pipe 111. In the gas-liquid distributor 120, the distribution container 130 has a circular structure, and eight larger parallelogram-shaped riser pipes 140 and two smaller triangular riser pipes 140 are distributed on the bottom plate 131. Each heat exchange tube 180 is a circular tube, and multiple liquid distribution holes 132 are distributed between the riser pipes 140. Each liquid distribution hole 132 is staggered from the heat exchange tube 180 in the horizontal direction, that is, it is not directly above the heat exchange tube 180. Whether it is a parallelogram-shaped riser pipe 140 or a triangular riser pipe 140, its projection along the liquid flow direction A (i.e., the vertical direction from top to bottom) covers multiple heat exchange tubes 180. Furthermore, in the parallelogram-shaped riser pipe 140, the projections of the two longer sides span seven heat exchange tubes 180, and the projections of the two shorter sides span two heat exchange tubes 180; in the triangular riser pipe 140, the projection of each side spans three heat exchange tubes 180.

[0045] In other embodiments, the riser pipe 140 can have different shapes and structures, not limited to the parallelogram and triangular structures of this embodiment. Different riser pipes 140 can have different orifice sizes. Not every riser pipe 140's projection covers multiple heat exchange tubes 180, but at least one riser pipe 140's projection covers multiple heat exchange tubes 180 to reduce the resistance when steam passes through the riser pipe 140. In other embodiments, based on the riser pipes 140 arranged in this embodiment, riser pipes 140 with smaller orifices can also be provided at the inner wall edge of the distribution container 130. Their projections can cover those heat exchange tubes 180 that cannot be covered by the parallelogram riser pipes 140, allowing steam generated by the heat exchange tubes 180 located at the inner wall edge to pass through.

[0046] The gas-liquid distribution device 100 has several riser pipes 140 and several liquid distribution holes 132 arranged on the base plate 131. The liquid distribution holes 132 are distributed in a dispersed manner to achieve uniform liquid distribution. Based on ensuring uniform liquid distribution, the riser pipes 140 cover multiple heat exchange tubes 180, increasing the pipe opening area. This reduces the resistance encountered by the steam generated during heat exchange as it passes through the riser pipes 140, thus reducing the pressure loss of the gas inside the cylinder 110. Simultaneously, one or more sides of the riser pipes 140 project along the liquid flow direction A across at least two heat exchange tubes 180. This allows the steam from the two or more heat exchange tubes 180 that are crossed to enter the riser pipes 140 from the side of the adjacent riser pipe, shortening the flow path and further reducing steam flow resistance and pressure loss. Since gases flow better than liquids, this gas-liquid distribution device 100 reduces gas flow resistance while ensuring uniform liquid distribution. This is achieved by increasing the coverage area of ​​the riser pipe 140 and shortening the path of vapor entering the riser pipe 140. This arrangement does not affect the uniformity of liquid distribution and also reduces pressure loss, ensuring a stable gas pressure entering downstream equipment. Furthermore, this arrangement of the riser pipe 140 minimizes the number of pipes required, simplifying manufacturing.

[0047] In this embodiment, as Figure 5 As shown, in the heat exchange tubes 180 covered by the projection of the riser pipe 140 along the liquid flow direction A, each heat exchange tube 180 has only a partial opening covered. However, in other embodiments, by adjusting the positions of the liquid distribution hole 132, the heat exchange tubes 180, and the riser pipe 140, each heat exchange tube 180 can be positioned within the projection coverage area of ​​the riser pipe 140 along the liquid flow direction A. This ensures that the steam generated by each heat exchange tube 180 can flow out from the covered riser pipe 140, shortening the gas flow path and thus reducing the resistance encountered by the steam. In this case, the projection of the side of the riser pipe 140 along the liquid flow direction A can either span multiple heat exchange tubes or not span them, with all multiple heat exchange tubes within the area covered by the respective sides of the riser pipe.

[0048] Among them, such as Figure 3 , Figure 5 and Figure 6 As shown, the gas-liquid distribution device 100 also includes a liquid inlet pipe 150, which includes an inlet pipe section 152 and an outlet pipe section 151. The inlet pipe section 152 is used to introduce the liquid for the chemical reaction from the outside. The inlet pipe section 152 passes horizontally through the cylinder 110 and extends into the inner cavity of the cylinder 110. The outlet pipe section 151 is perpendicular to and communicates with the inlet pipe section 152. The outlet pipe section 151 is located at the center of the distribution container 130, with its outlet facing the bottom plate 131 of the distribution container 130.

[0049] Eight parallelogram-shaped riser pipes 140 are arranged in two rings around the outlet pipe section 151. The inner and outer rings of riser pipes 141 are spaced at a certain distance along the radial direction of the outlet pipe. The four parallelogram-shaped riser pipes 140 in the inner ring form an approximately rhomboid structure, and the four parallelogram-shaped riser pipes 140 in the outer ring form an approximately hexagonal structure.

[0050] In this structure, the gas-liquid distribution device 100 positions the outlet section 151 of the inlet pipe 150 at the center of the distribution container 130, allowing the liquid to flow from the center outwards, which facilitates uniform liquid distribution. Several riser pipes 140 are arranged around the outlet pipe to form a polygonal multi-ring structure of riser pipes 141. Compared to other distribution structures, this structure improves the open area ratio (the ratio of the sum of the open areas of the riser pipes 140 to the area of ​​the base plate 131), preventing droplets from being blown away by the gas phase and ensuring vapor purity. Simultaneously, each riser pipe 140 also spaces multiple liquid distribution holes 132, which are generally arranged in a rhomboid pattern, further contributing to the uniformity of liquid distribution.

[0051] The outlet pipe section 151 is further provided with a guide plate 153 below the liquid flow direction A, which can buffer the flow rate of the liquid and guide the liquid to flow evenly around the guide plate 153. The outer diameter of the guide plate 153 is larger than the inner diameter of the outlet pipe section 151, ensuring that the liquid flowing out of the outlet pipe section 151 can be effectively buffered and will not flow directly into the distribution container 130 from the outlet.

[0052] like Figure 5 As shown, the projection of the liquid distribution hole 132 along the liquid flow direction A is located between three adjacent heat exchange tubes 180. This arrangement can shorten the liquid flow path, because after the liquid dripping from the liquid distribution hole 132 falls onto the tube sheet 160 below, the flow path of the liquid to any of its adjacent heat exchange tubes 180 is the shortest, thereby improving the liquid distribution efficiency, allowing the liquid to evaporate more quickly, and maintaining or increasing the gas pressure inside the cylinder 110.

[0053] like Figure 3 and Figure 4As shown, a tube sheet 160 is also provided below the gas-liquid distributor 120 along the liquid flow direction A. The tube sheet 160 is also provided with a film-covered tube 170 that is detachably connected to the heat exchange tube 180 in a one-to-one correspondence. The film-covered tube 170 is a circular tube coaxial with the heat exchange tube 180, which is fitted into the top inner cavity of the heat exchange tube 180 and welded in place. Liquid dripping from the liquid distribution hole 132 onto the tube sheet 160 is guided into the heat exchange tube 180 by the film-covered tube 170. The projection of the riser tube 140 along the liquid flow direction A covers multiple film-covered tubes 170. Since the film-covered tubes 170 and the heat exchange tubes 180 are in a one-to-one correspondence, the projection of the riser tube 140 along the liquid flow direction A covers multiple film-covered tubes 170, ensuring that the vapor evaporated from the heat exchange tube 180 flows through the film-covered tubes 170 and from the covered riser tubes 140.

[0054] Among them, such as Figure 7 and Figure 8 As shown, the circumferential wall of the membrane tube 170 has several slots 171, which act like small windows on the membrane tube 170. The slot wall 172 extends into the inner cavity of the membrane tube 170 like a window panel. The angle α between the tangential surface 173 of the tube wall at the slot 171 and the slot wall 172 ranges from 5° to 45°. The length L of the slot wall 172 along the axial direction of the membrane tube 170 ranges from 20mm to 80mm. Through these multiple slots 171, the liquid is evenly distributed to each membrane tube 170 and introduced into the heat exchange tube 180. The angle α between the tangential surface 173 of the tube wall at the slot 171 and the slot wall 172 is set within the range of 5° to 45°, which helps to balance the flow rate of the liquid entering the membrane tube 170 and the evaporation rate in the heat exchange tube 180. The flow rate is neither too fast to allow for evaporation nor too slow to result in insufficient steam, thus achieving effective distribution and improving the evaporation effect.

[0055] In other embodiments, preferably, the opening of the riser pipe 140 can be cut at an angle, that is, the opening is inclined to the cross-section of the riser pipe 140 to form a cut, and the angle of the cut is 45°. Using this angled cut can increase the flow rate of gas through the riser pipe 140.

[0056] In different applications, the number, shape and size of the riser pipes 140 can be adjusted as needed. However, preferably, the total area of ​​all riser pipes 140 is 25% to 50% of the area of ​​the base plate 131. This ratio range can balance the flow rate of the gas distribution and the flow rate of the liquid distribution, and achieve a balance between the gas distribution and the liquid distribution.

[0057] Example 2

[0058] This embodiment provides a falling film evaporator 10, which includes a gas-liquid distribution device 100 as described in Embodiment 1. Through the gas-liquid distribution device 100 as described in Embodiment 1, the falling film evaporator 10 minimizes the resistance encountered by the steam generated during heat exchange as it passes through the riser pipe 140, reduces the pressure loss of the gas inside the cylinder 110, and allows the discharged gas to flow into downstream equipment, thereby improving the pneumatic pressure power supplied to the downstream equipment. By adjusting the size and distribution of the riser pipe 140, the projection of multiple sides of the riser pipe 140 along the liquid flow direction A spans at least two heat exchange tubes 180, further reducing steam flow resistance and pressure loss; it also ensures that the number of riser pipes 140 is not excessive, facilitating manufacturing.

[0059] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. A gas-liquid distribution device, the gas-liquid distribution device (100) comprising a cylindrical body (110), wherein a gas-liquid distributor (120) and a plurality of heat exchange tubes (180) are sequentially arranged inside the cylindrical body (110) along the liquid flow direction (A), characterized in that, The gas-liquid distributor (120) includes a distribution container (130), and the bottom plate (131) of the distribution container (130) is provided with a plurality of gas riser pipes (140) for gas flow and a plurality of liquid distribution holes (132) for liquid dispersion and dripping. At least one of the riser pipes (140) has its projection along the liquid flow direction (A) covering the plurality of heat exchange tubes (180); and the riser pipe (140) has its projection covering the plurality of heat exchange tubes (180), with at least one side of the riser pipe (140) having its projection along the liquid flow direction (A) spanning at least two of the heat exchange tubes (180).

2. The gas-liquid distribution device as described in claim 1, characterized in that, Each of the heat exchange tubes (180) is within the projection coverage of the riser tube (140) along the liquid flow direction (A).

3. The gas-liquid distribution device as described in claim 1, characterized in that, The gas-liquid distribution device also includes a liquid inlet pipe (150), and the outlet pipe section (151) of the liquid inlet pipe (150) is located at the center of the distribution container. A plurality of the riser pipes (140) are arranged in multiple rings around the outlet pipe section (151), the multiple rings of the riser pipes (141) are arranged at radial intervals along the outlet pipe section (151), and each ring of the riser pipes (141) includes a plurality of the riser pipes (140) arranged in a polygonal structure.

4. The gas-liquid distribution device as described in claim 3, characterized in that, The outlet pipe section (151) is further provided with a guide plate (153) below the liquid flow direction (A), and the outer diameter of the guide plate (153) is larger than the inner diameter of the outlet pipe section (151).

5. The gas-liquid distribution device as described in claim 1, characterized in that, The projection of the liquid distribution hole (132) along the liquid flow direction (A) is located between the three adjacent heat exchange tubes (180).

6. The gas-liquid distribution device as described in claim 5, characterized in that, The gas-liquid distributor (120) is further provided with a tube sheet (160) below the liquid flow direction (A). The tube sheet (160) is also provided with a membrane tube (170) that is detachably connected to the heat exchange tube (180) in a one-to-one correspondence. The membrane tube (170) is used to guide the liquid dripping onto the tube sheet (160) into the heat exchange tube (180). The projection of the riser (140) along the liquid flow direction (A) covers multiple membrane tubes (170).

7. The gas-liquid distribution device as described in claim 6, characterized in that, The circumferential wall of the membrane tube (170) has several slots (171), the groove wall (172) of the slot (171) extends into the inner cavity of the membrane tube (170), the angle (α) between the tangential surface (173) of the tube wall at the slot (171) and the groove wall (172) is in the range of 5°~45°, and the length (L) of the groove wall (172) along the axial direction of the membrane tube (170) is in the range of 20mm-80mm.

8. The gas-liquid distribution device as described in claim 1, characterized in that, The opening of the riser pipe (140) is inclined to the cross-section of the riser pipe (140), and the inclination angle of the opening is 45°.

9. The gas-liquid distribution device as described in claim 1, characterized in that, The total area of ​​all the riser pipes (140) accounts for 25% to 50% of the area of ​​the base plate (131).

10. A falling film evaporator, characterized in that, The falling film evaporator (10) includes a gas-liquid distribution device (100) as described in any one of claims 1-9.

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