Horizontal tube falling film evaporator

Abstract

A first-stage liquid distributor, a first-stage heat exchange tube group, a second-stage liquid distributor and a second-stage heat exchange tube group are sequentially arranged in a shell from top to bottom, and both the first-stage liquid distributor and the second-stage liquid distributor can distribute cooling liquid into a plurality of strip-shaped cooling liquid flows. The strip-shaped cooling liquid flow extends in the length direction of the heat exchange pipe. A strip-shaped cooling liquid flow generated by the first-stage liquid distributor flows through the first-stage heat exchange pipe group to complete heat exchange, then liquid cooling liquid is stacked on the second-stage liquid distributor, the stacked liquid cooling liquid is distributed into a plurality of strip-shaped cooling liquid flows again by the second-stage liquid distributor, and then the strip-shaped cooling liquid flow generated by the second-stage liquid distributor flows through the second-stage heat exchange pipe group to complete heat exchange. In this way, cooling liquid can be evenly distributed in the direction of the heat exchange pipe, stable sheet flow can be formed, the quality of a liquid film on the surface of the heat exchange pipe is improved, and the heat exchange efficiency is greatly improved.

Description

Technical Field

[0001] The invention relates to the field of tube group cooling equipment, and in particular to a horizontal tube falling film evaporator. Background Art

[0002] As a high-efficiency cooling equipment, the horizontal tube falling film evaporator is widely used in the chemical, food, pharmaceutical, seawater desalination and other industries. The traditional horizontal tube falling film evaporator is mainly composed of a shell, a liquid distributor, a horizontal tube bundle and other components. The refrigerant flows out from the distributor just above the shell, forms a uniform liquid film on the surface of the horizontal tube, and flows downward along the tube bundle, and continues to form a liquid film in the lower tube bundle and flows downward. In this process, the liquid film formed by the refrigerant exchanges heat with the hot fluid in the tube and evaporates through phase change. The spraying method of the liquid distributor, the internal tube array layout and the gas disturbance are the main factors affecting the uniform distribution of the liquid film and the heat exchange efficiency.

[0003] In order to further improve the heat transfer efficiency of the horizontal tube falling film evaporator, the following technical issues are mainly involved in improvement and optimization: 1. The liquid film flow on the surface of the horizontal tube is unstable and cannot form a continuous columnar flow; 2. The turbulence caused by gas disturbance and insufficient liquid flow cause the deviation of the liquid flow between the upper and lower tubes in the vertical direction; 3. The splashing and incomplete evaporation of droplets cause the accumulation of refrigerant at the bottom of the shell.

[0004] During the operation of the evaporator, the above problems will cause local drying of the surface of the horizontal tube bundle, especially large-scale drying of the middle and lower tube bundles. At the same time, the refrigerant accumulated at the bottom does not form effective contact with the horizontal tube bundle, making it difficult to quickly undergo heat transfer phase change, reducing the heat exchange efficiency. When accumulated to a certain extent, it will even immerse the lower tube bundle.

[0005] At present, many researchers have improved the heat exchange efficiency of the evaporator by improving the structure of the liquid distributor and the arrangement of the tube bundle. Common tube bundle structures include rotating triangle arrangement, rotating square arrangement, etc., or adjusting the distribution structure of the liquid distributor to make the refrigerant more evenly distributed to the horizontal tube surface. These structures have improved the problem of uneven distribution of liquid film on the surface of the middle and upper tube bundles to a certain extent, but it is still difficult to solve 1. The problem of liquid accumulation at the bottom; 2. The problem of poor quality and large-area drying of the liquid film on the lower horizontal tube. Therefore, in order to improve the liquid film formation effect on the surface of the tube bundle and enhance the heat exchange efficiency of the horizontal tube falling film evaporator, it is necessary to take further measures to solve the problems of excessive refrigerant spray flow on the upper tube group and local dry spots on the lower tube group. Summary of the invention

[0006] In order to solve the problems of local dry spots on the tube group and low heat exchange efficiency in the heat exchange process in the prior art, the purpose of the present invention is to provide a horizontal tube falling film evaporator, which can effectively improve the heat exchange capacity and effectively solve the problem of local dry spots on the tube group.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a horizontal tube falling film evaporator, comprising a shell, a first-level liquid distributor, a first-level heat exchange tube group, a second-level liquid distributor, a second-level heat exchange tube group, an exhaust system and a circulation system; the first-level liquid distributor, the first-level heat exchange tube group, the second-level liquid distributor and the second-level heat exchange tube group are arranged in the shell from top to bottom, and the first-level heat exchange tube group and the second-level heat exchange tube group each include a plurality of stacked heat exchange tubes; the first-level liquid distributor and the second-level liquid distributor can distribute the coolant into a plurality of strip-shaped coolant flows, and the strip-shaped coolant flows extend along the length direction of the heat exchange tube; the first-level liquid distributor The strip cooling liquid flow generated by the liquid distributor flows through the primary heat exchange tube group to complete the heat exchange, and then the liquid cooling liquid accumulates on the secondary liquid distributor, and then the secondary liquid distributor redistributes the accumulated liquid cooling liquid into multiple strip cooling liquid flows, and then the strip cooling liquid flow generated by the secondary liquid distributor flows through the secondary heat exchange tube group to complete the heat exchange, and then the liquid cooling liquid that completes the heat exchange on the secondary heat exchange tube group is collected by the ring system and reconfigured on the secondary liquid distributor to continue to cool the secondary heat exchange tube group; wherein, the gaseous cooling liquid formed by the heat exchange at the primary heat exchange tube group and the secondary heat exchange tube group is discharged from the shell by the exhaust system.

[0008] Preferably, the first-level liquid distributor includes a first-level liquid distribution plate, a first-level nozzle and a first-level guide plate; the first-level guide plate is vertically arranged, the first-level guide plate extends along the length direction of the heat exchange tube, and multiple first-level guide plates are arranged horizontally; multiple first-level nozzles are arranged on the first-level guide plate, and the first-level nozzles can guide the coolant stored on the first-level liquid distribution plate to the first-level guide plate; in this way, the coolant sprayed by the multiple first-level nozzles forms a strip-shaped cooling liquid flow under the drainage of the first-level guide plate.

[0009] Preferably, the first-level nozzle includes a first-level nozzle shell, a first-level drainage pipe and a first-level overflow plate. The first-level drainage pipe is vertically arranged, the bottom of the first-level drainage pipe is inserted into the first-level nozzle shell, the first-level drainage pipe is fixedly connected to the first-level nozzle shell, the first-level overflow plate is fixed in the first-level nozzle shell, the first-level overflow plate is located below the first-level drainage pipe, a first-level overflow groove is arranged on the top of the first-level overflow plate, the first-level overflow groove is located below the first-level drainage pipe, a first-level drainage hole connected to the interior of the first-level nozzle shell is opened at the bottom, the first-level drainage plate is inserted into the first-level drainage hole, the first-level drainage plate is fixedly connected to the shell, and the left and right sides of the first-level drainage plate are gap-matched with the first-level drainage hole.

[0010] Preferably, the first-stage liquid distributor further comprises a first-stage diversion pipe, and the coolant in the high-pressure liquid storage tank above the shell can be delivered to the first-stage liquid distribution plate through the first-stage diversion pipe.

[0011] Preferably, the secondary guide plate is vertically arranged and extends along the length direction of the heat exchange tube, and multiple secondary guide plates are arranged horizontally; the secondary liquid distributor includes a secondary liquid distribution plate and a secondary nozzle; multiple secondary nozzles are arranged on the secondary guide plate, and the secondary nozzles can guide the coolant stored on the secondary liquid distribution plate to the secondary guide plate.

[0012] Preferably, the secondary liquid distribution plate includes a plurality of downwardly protruding drainage portions, the drainage portions are provided with liquid accumulation holes, and the tops of the liquid accumulation holes are trumpet-shaped; the secondary nozzle includes a secondary nozzle shell and a secondary overflow plate, the drainage portions on the secondary liquid distribution plate are inserted into the secondary nozzle shell, the secondary overflow plate is fixed in the secondary nozzle shell, a secondary overflow groove is provided on the top of the secondary overflow plate, the secondary overflow groove is located below the liquid accumulation holes on the drainage portions, a secondary drainage hole connected to the interior of the secondary nozzle shell is provided at the bottom of the secondary nozzle shell, the secondary drainage plate is inserted into the secondary drainage hole, the secondary drainage plate is fixedly connected to the secondary nozzle shell, and the left and right sides of the secondary drainage plate are both gap-matched with the secondary drainage hole.

[0013] Preferably, the exhaust system includes a steam channel formed by the gap between the left and right ends of the secondary liquid distributor and the shell, and two steam outlets are arranged on the top of the shell.

[0014] Preferably, a plurality of vertically arranged air ducts are provided at the steam channel, and the coolant vaporized at the secondary heat exchange tube group can be discharged from the air ducts.

[0015] Preferably, the transverse length on the secondary liquid distribution plate is not less than the transverse length on the primary heat exchange tube group; the transverse length of the steam channel does not exceed the transverse length of the primary heat exchange tube group.

[0016] Preferably, the circulation system includes a spherical liquid storage bag and an ejection mechanism. A liquid outlet is provided at the bottom of the shell. The spherical liquid storage bag is arranged at the bottom of the shell and covers the liquid outlet. The liquid coolant that completes heat exchange at the secondary heat exchange tube group can be gathered in the spherical liquid storage bag; the ejection mechanism can deliver the coolant in the spherical liquid storage bag to the secondary liquid distribution plate.

[0017] The beneficial effects of the technical solution of the present invention are as follows: in this way, the coolant is evenly distributed along the direction of the heat exchange tube, and can form a stable sheet flow, thereby improving the quality of the liquid film on the surface of the heat exchange tube; the secondary liquid distribution recycling method, on the one hand, continues to form a stable sheet flow, and the increased airway structure also greatly avoids the impact on the quality of the upper liquid film; on the other hand, the secondary liquid distribution not only realizes the recycling of the accumulated liquid at the bottom, but the improved secondary liquid distributor structure also greatly improves the quality of the liquid film of the lower heat exchange group tube, and greatly reduces the dry area on the surface of the lower heat exchange tube; the above scheme can optimize the process heat exchange of the first-stage heat exchange tube group and the second-stage heat exchange tube group, thereby greatly improving the heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a falling film evaporator; Figure 2 It is a structural schematic diagram of a first-level liquid distributor; Figure 3 It is a schematic diagram of the connection structure between the first-stage nozzle and the first-stage guide plate; Figure 4 It is a schematic diagram of the connection structure between the secondary liquid distribution plate and the secondary nozzle; Figure 5 It is a structural schematic diagram of the first-level nozzle; Figure 6 It is a structural schematic diagram of the secondary nozzle; Figure 7 It is a schematic diagram of the connection structure between the shell and the spherical liquid storage capsule; Figure 8 It is a structural schematic diagram of the secondary liquid distribution plate.

[0019] Reference numerals: 1, housing; 11, steam outlet; 12, liquid outlet; 2. First-level liquid distributor; 21. First-level flow divider; 22. First-level liquid distributor plate; 23. First-level nozzle; 231. First-level nozzle housing; 232. First-level drainage hole; 233. First-level drainage pipe; 234. First-level overflow plate; 235. First-level overflow trough; 24. First-level drainage plate; 3. Primary heat exchange tube group; 4. Secondary liquid distributor; 41. Secondary liquid distributor plate; 411. drainage portion; 412. liquid accumulation hole; 42. guide plate; 421. liquid storage tank; 43. secondary drainage plate; 44. steam channel; 45. secondary nozzle; 451. secondary nozzle housing; 452. secondary overflow plate; 453. secondary overflow tank; 454. secondary drainage hole; 5. Secondary heat exchange tube group; 6. Circulatory system; 61. Reflux pipe; 62. Ejector; 63. Drainage tube; 64. Spherical liquid storage bag; 7. Exhaust system; 8. High-pressure liquid storage tank. DETAILED DESCRIPTION

[0020] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0022] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise clearly specified.

[0023] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0025] The following embodiments are described in Figure 1 The directions shown in the figure shall prevail, wherein the location of the high-pressure liquid storage tank is "up", the location of the spherical liquid storage capsule is "down", and the locations of the two ejectors are "left" and "right"; Figure 1 The left and right directions are the "horizontal" and "width" directions. Figure 1 The front-to-back direction is "longitudinal". Example

[0026] like Figures 1 to 8 A horizontal tube falling film evaporator is shown, comprising a shell 1, a primary liquid distributor 2, a primary heat exchange tube group 3, a secondary liquid distributor 4, a secondary heat exchange tube group 5, an exhaust system 7 and a circulation system 6; the primary liquid distributor 2, the primary heat exchange tube group 3, the secondary liquid distributor 4 and the secondary heat exchange tube group 5 are sequentially arranged in the shell 1 from top to bottom, and the primary heat exchange tube group 3 and the secondary heat exchange tube group 5 each include a plurality of stacked heat exchange tubes; The first-stage liquid distributor 2 and the second-stage liquid distributor 4 can both distribute the coolant into a plurality of strip-shaped coolant flows, and the strip-shaped coolant flows extend along the length direction of the heat exchange tube; The strip-shaped cooling liquid flow generated by the primary liquid distributor 2 flows through the primary heat exchange tube group 3 to complete the heat exchange, and then the liquid cooling liquid accumulates on the secondary liquid distributor 4, and then the secondary liquid distributor 4 redistributes the accumulated liquid cooling liquid into multiple strip-shaped cooling liquid flows, and then the strip-shaped cooling liquid flow generated by the secondary liquid distributor 4 flows through the secondary heat exchange tube group 5 to complete the heat exchange, and then the liquid cooling liquid that completes the heat exchange on the secondary heat exchange tube group 5 is collected by the ring system and reconfigured on the secondary liquid distributor 4 to continue to complete the cooling for the secondary heat exchange tube group 5; wherein, the gaseous cooling liquid formed by the heat exchange at the primary heat exchange tube group 3 and the secondary heat exchange tube group 5 is discharged from the shell 1 by the exhaust system 7.

[0027] With such arrangement, the improved liquid distributor structure of the present invention allows the coolant to be evenly distributed along the direction of the heat exchange tubes, and can form a stable sheet flow, thereby improving the quality of the liquid film on the surface of the heat exchange tubes; the secondary liquid distribution recycling method, on the one hand, continues to form a stable sheet flow, and the increased airway structure also greatly avoids the impact on the quality of the upper liquid film; on the other hand, the secondary liquid distribution not only realizes the recycling of the accumulated liquid at the bottom, but the improved secondary liquid distributor 4 structure also greatly improves the quality of the liquid film of the lower heat exchange group tubes, and greatly reduces the dry area on the surface of the lower heat exchange tubes; the above scheme can optimize the process heat exchange of the first-stage heat exchange tube group 3 and the second-stage heat exchange tube group, thereby greatly improving the heat exchange efficiency.

[0028] In this embodiment, Figure 2 , Figure 3 and Figure 5 As shown, the first-level liquid distributor 2 includes a first-level liquid distribution plate 22, a first-level nozzle 23 and a first-level guide plate 24; the first-level guide plate 24 is vertically arranged, the first-level guide plate 24 extends along the length direction of the heat exchange tube, and multiple first-level guide plates 24 are arranged horizontally; multiple first-level nozzles 23 are arranged on the first-level guide plate 24, and the first-level nozzles 23 can guide the cooling liquid stored on the first-level liquid distribution plate 22 to the first-level guide plate 24; in this way, the cooling liquid sprayed by the multiple first-level nozzles 23 forms a strip-shaped cooling liquid flow on the first-level guide plate 24.

[0029] Furthermore, the first-level nozzle 23 includes a first-level nozzle shell 231, a first-level drainage pipe 233 and a first-level overflow plate 234. The first-level drainage pipe 233 is vertically arranged, and the bottom of the first-level drainage pipe 233 is inserted into the first-level nozzle shell 231. The first-level drainage pipe 233 is fixedly connected to the first-level nozzle shell 231. The first-level overflow plate 234 is fixed in the first-level nozzle shell 231. The first-level overflow plate 234 is located below the first-level drainage pipe 233. A first-level overflow groove 235 is arranged on the top of the first-level overflow plate 234. The first-level overflow groove 235 is located below the first-level drainage pipe 233. The bottom of the first-level nozzle shell 231 is provided with a first-level drainage hole 232 connected to the interior thereof. The first-level drainage plate 24 is inserted into the first-level drainage hole 232. The first-level drainage plate 24 is fixedly connected to the shell 1, and the left and right sides of the first-level drainage plate 24 are both gap-matched with the first-level drainage hole 232.

[0030] Furthermore, the primary overflow plate 234 is arc-shaped, and the arc-shaped top of the primary overflow plate 234 forms a primary overflow groove 235 ; the primary drainage hole 232 is located directly below the primary overflow plate 234 .

[0031] In this embodiment, Figure 1 and Figure 2 As shown, the primary liquid distributor 2 further includes a primary shunt pipe 21 , and the coolant in the high-pressure liquid storage tank 8 above the shell 1 can be delivered to the primary liquid distribution plate 22 through the primary shunt pipe 21 .

[0032] In this embodiment, the first-level heat exchange tube group 3 includes a plurality of first-level heat exchange tube groups arranged vertically, the first-level heat exchange tube group includes a plurality of first-level heat exchange tubes, the plurality of first-level heat exchange tubes are arranged horizontally, and the plurality of first-level heat exchange tubes are arranged alternately up and down; the plurality of strip-shaped cooling liquid flows generated by the first-level liquid distributor 2 are arranged horizontally, and the plurality of strip-shaped cooling liquid flows are arranged one-to-one with the first-level heat exchange tubes in the first-level heat exchange tube group; the plurality of first-level guide plates 24 on the first-level liquid distributor 2 are arranged one-to-one with the plurality of first-level heat exchange tubes in the first-level heat exchange tube group, and two adjacent first-level guide plates 24 are arranged in staggered heights.

[0033] In this embodiment, Figure 4 and Figure 6 As shown, the secondary guide plate 43 is vertically arranged, the secondary guide plate 43 extends along the length direction of the heat exchange tube, and multiple secondary guide plates 43 are arranged horizontally; the secondary liquid distributor 4 includes a secondary liquid distribution plate 41, a secondary nozzle 45 and a secondary guide plate 43; multiple secondary nozzles 45 are arranged on the secondary guide plate 43, and the secondary nozzles 45 can guide the coolant stored on the secondary liquid distribution plate 41 to the secondary guide plate 43; in this way, the coolant sprayed by the multiple secondary nozzles 45 forms a strip-shaped coolant flow on the drainage of the secondary guide plate 43.

[0034] In this embodiment, Figure 4 and Figure 6As shown, the secondary liquid distribution plate 41 includes a plurality of downwardly protruding drainage portions 411, and the drainage portions 411 are provided with liquid accumulation holes 412, and the top of the liquid accumulation holes 412 is trumpet-shaped; the secondary nozzle 45 includes a secondary nozzle shell 451 and a secondary overflow plate 452, the drainage portion 411 on the secondary liquid distribution plate 41 is inserted into the secondary nozzle shell 451, the secondary overflow plate 452 is fixed in the secondary nozzle shell 451, and a secondary overflow groove 453 is provided on the top of the secondary overflow plate 452, and the secondary overflow groove 453 is located below the liquid accumulation holes 412 on the drainage portion 411, and a secondary drainage hole 454 connected to the interior of the secondary nozzle shell 451 is opened at the bottom of the secondary nozzle shell 451, and the secondary drainage plate 43 is inserted into the secondary drainage hole 454, and the secondary drainage plate 43 is fixedly connected to the secondary nozzle 45 shell 1, and the left and right sides of the secondary drainage plate 43 are both gap-matched with the secondary drainage hole 454.

[0035] Furthermore, the secondary overflow plate 452 is arc-shaped, and the arc-shaped top of the secondary overflow plate 452 forms a secondary overflow groove 453; the secondary drainage hole 454 is located directly below the secondary overflow plate 452; the top of the secondary drainage plate 43 passes through the secondary overflow plate 452 and is inserted into the liquid accumulation hole 412 on the secondary liquid distributor 4.

[0036] In this embodiment, the secondary heat exchange tube group 5 includes a plurality of secondary heat exchange tube groups arranged vertically, the secondary heat exchange tube groups include a plurality of secondary heat exchange tubes, the plurality of secondary heat exchange tubes are arranged horizontally, and the plurality of secondary heat exchange tubes are alternately arranged vertically; the plurality of strip-shaped cooling liquid flows generated by the secondary liquid distributor 4 are arranged horizontally, and the plurality of strip-shaped cooling liquid flows are arranged one-to-one with the secondary heat exchange tubes in the secondary heat exchange tube group; the plurality of secondary guide plates 43 on the secondary liquid distributor 4 are arranged one-to-one with the plurality of secondary heat exchange tubes in the secondary heat exchange tube group, and two adjacent secondary guide plates 43 are arranged in staggered heights.

[0037] In this embodiment, Figure 1 , Figure 4 and Figure 8 As shown, the exhaust system 7 includes a steam channel 44 formed by the gap between the left and right ends of the secondary liquid distributor 4 and the shell 1, and two steam outlets 11 are arranged on the top of the shell 1. The evaporated cooling can also be discharged from the shell 1 through the steam outlet 11.

[0038] Furthermore, a partition is provided at the steam channel 44, and a plurality of vertically arranged air guide pipes are provided on the partition, and the coolant vaporized at the secondary heat exchange tube group 5 can be discharged from the air guide pipes. The drainage effect of the steam channel 44 structure prevents the upper refrigerant from being deviated in the vertical direction due to gas blowing during the flow process, thereby improving the turbulence phenomenon caused by the vaporization and rising of the refrigerant below on the liquid film on the surface of the upper pipe.

[0039] Furthermore, the transverse cross-section of the shell 1 is curved, and the high-temperature steam can rise along the curved inner wall of the shell 1 and be discharged from the steam outlet 12 .

[0040] Furthermore, the transverse length of the secondary liquid distribution plate 41 is not less than the transverse length of the primary heat exchange tube group 3, and the transverse length of the steam channel 44 is not greater than the transverse length of the primary heat exchange tube group 3. In this way, it is possible to fully avoid the steam from affecting the flow of the cooling liquid on the primary heat exchange tube group 3.

[0041] In this embodiment, Figure 1 and Figure 7 As shown, the circulation system 6 includes a spherical liquid storage capsule 64 and an ejection mechanism. The bottom of the shell 1 is provided with a liquid outlet 12. The spherical liquid storage capsule 64 is arranged at the bottom of the shell 1 and covers the liquid outlet 12. The liquid coolant that completes heat exchange at the secondary heat exchange tube group 5 can be gathered in the spherical liquid storage capsule 64; the ejection mechanism can send the coolant in the spherical liquid storage capsule 64 to the secondary liquid distribution plate 41. In this way, the coolant can be circulated.

[0042] Furthermore, the ejection mechanism includes an ejector 62 and a drainage pipe 63. The spherical liquid storage bag 64 is connected to one end of the ejector 62 through the reflux pipe 61, and the other end of the ejector 62 is connected to the drainage pipe 63. The ejector 62 can deliver the coolant in the spherical liquid storage bag 64 to the secondary liquid distribution plate 41 through the drainage pipe 63.

[0043] Furthermore, there are two groups of ejection mechanisms, which are respectively arranged at the left and right ends of the secondary liquid distribution plate 41. In this way, the uniformity of the liquid on the secondary liquid distribution plate 41 can be ensured.

[0044] Furthermore, an overflow channel 641 is provided between the spherical liquid storage capsule 64 and the shell 1, and an elastic air relief valve 642 is provided in the overflow channel 641. In this way, when the liquid in the spherical liquid storage capsule 64 is low, the steam at the secondary heat exchange tube group 5 leaves from the upper steam channel 44; when the liquid in the spherical liquid storage capsule 64 is high, the steam pressure at the secondary heat exchange tube group 5 increases, and at this time the elastic air relief valve 642 is pushed open, and the coolant steam in the secondary heat exchange area can be discharged from the overflow channel 641 at the bottom, thereby alleviating the air flow disturbance inside the shell 1.

[0045] In this embodiment, Figure 4 and Figure 8 As shown, a guide plate 42 is provided in the middle position of the secondary liquid distribution plate 41 in the front-to-back direction, a liquid storage tank 421 is provided on the top of the guide plate 42, and a plurality of drainage holes are provided on the sides of the liquid storage tank 421 in the front-to-back direction. The drainage tube 63 can deliver the cooling liquid in the spherical liquid storage bag 64 to the guide plate 42, and the cooling liquid entering the guide plate 42 can be delivered to the secondary guide plate 42 through the drainage holes.

[0046] Furthermore, the front and rear parts of the secondary liquid distribution plate 41 are tilted downward, so that the secondary liquid distribution plate 41 is in an inverted V shape; Furthermore, the width of the liquid storage tank 421 of the guide plate 42 gradually narrows from the middle position to the left and right ends. In this way, the special structure of the guide plate 42 with narrow sides and wide middle effectively improves the problem of uneven distribution of coolant flow and too small flow at the end. In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0047] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A horizontal tube falling film evaporator, characterized in that: The invention comprises a shell (1), a first-level liquid distributor (2), a first-level heat exchange tube group (3), a second-level liquid distributor (4), a second-level heat exchange tube group (5), an exhaust system (7) and a circulation system (6); the first-level liquid distributor (2), the first-level heat exchange tube group (3), the second-level liquid distributor (4) and the second-level heat exchange tube group (5) are arranged in sequence from top to bottom in the shell (1); the first-level heat exchange tube group (3) and the second-level heat exchange tube group (5) both comprise a plurality of heat exchange tubes arranged in a stacked manner; The first-stage liquid distributor (2) and the second-stage liquid distributor (4) are both capable of distributing the coolant into a plurality of strip-shaped coolant flows, and the strip-shaped coolant flows extend along the length direction of the heat exchange tube; The strip-shaped cooling liquid flow generated by the first-level liquid distributor (2) flows through the first-level heat exchange tube group (3) to complete heat exchange, and then the liquid cooling liquid accumulates on the second-level liquid distributor (4), and then the second-level liquid distributor (4) redistributes the accumulated liquid cooling liquid into a plurality of strip-shaped cooling liquid flows, and then the strip-shaped cooling liquid flow generated by the second-level liquid distributor (4) flows through the second-level heat exchange tube group (5) to complete heat exchange, and then the liquid cooling liquid that completes heat exchange on the second-level heat exchange tube group (5) is collected by the loop system and reconfigured on the second-level liquid distributor (4) to continue to cool the second-level heat exchange tube group (5); wherein, the gaseous cooling liquid formed by the heat exchange at the first-level heat exchange tube group (3) and the second-level heat exchange tube group (5) is discharged from the shell (1) by the exhaust system (7).

2. A horizontal tube falling film evaporator according to claim 1, characterized in that: The first-level liquid distributor (2) comprises a first-level liquid distribution plate (22), a first-level nozzle (23) and a first-level guide plate (24); the first-level guide plate (24) is arranged vertically, the first-level guide plate (24) extends along the length direction of the heat exchange tube, and a plurality of first-level guide plates (24) are arranged horizontally; a plurality of first-level nozzles (23) are arranged on the first-level guide plate (24), and the first-level nozzles (23) can guide the cooling liquid stored on the first-level liquid distribution plate (22) to the first-level guide plate (24); thus, the cooling liquid sprayed by the plurality of first-level nozzles (23) forms a strip-shaped cooling liquid flow under the guide of the first-level guide plate (24).

3. A horizontal tube falling film evaporator according to claim 2, characterized in that: The primary nozzle (23) comprises a primary nozzle housing (231), a primary drainage pipe (233) and a primary overflow plate (234); the primary drainage pipe (233) is arranged vertically, the bottom of the primary drainage pipe (233) is inserted into the primary nozzle housing (231), the primary drainage pipe (233) is fixedly connected to the primary nozzle housing (231), the primary overflow plate (234) is fixed in the primary nozzle housing (231), and the primary overflow plate (234) is located below the primary drainage pipe (233). A first overflow groove (235) is provided on the top of the first overflow plate (234), the first overflow groove (235) is located below the first drainage pipe (233), a first drainage hole (232) communicating with the interior of the first nozzle housing (231) is provided at the bottom of the first nozzle housing (231), the first drainage plate (24) is inserted into the first drainage hole (232), the first drainage plate (24) is fixedly connected to the housing (1), and the left and right sides of the first drainage plate (24) are both gap-matched with the first drainage hole (232).

4. The horizontal tube falling film evaporator according to claim 2, characterized in that: The first-stage liquid distributor (2) further comprises a first-stage flow distribution pipe (21), through which the coolant in the high-pressure liquid storage tank (8) above the housing (1) can be delivered to the first-stage liquid distribution plate (22).

5. The horizontal tube falling film evaporator according to claim 1, characterized in that: The secondary guide plate (43) is arranged vertically, the secondary guide plate (43) extends along the length direction of the heat exchange tube, and a plurality of secondary guide plates (43) are arranged horizontally; the secondary liquid distributor (4) comprises a secondary liquid distribution plate (41) and a secondary nozzle (45); a plurality of secondary nozzles (45) are arranged on the secondary guide plate (43), and the secondary nozzles (45) can guide the coolant stored on the secondary liquid distribution plate (41) to the secondary guide plate (43).

6. The horizontal tube falling film evaporator according to claim 5, characterized in that: The secondary liquid distribution plate (41) comprises a plurality of downwardly protruding drainage portions (411), the drainage portions (411) being provided with liquid accumulation holes (412), the tops of the liquid accumulation holes (412) being horn-shaped; the secondary nozzle (45) comprises a secondary nozzle housing (451) and a secondary overflow plate (452), the drainage portions (411) on the secondary liquid distribution plate (41) being inserted into the secondary nozzle housing (451), the secondary overflow plate (452) being fixed in the secondary nozzle housing (451), and the secondary overflow plate (452) being fixed in the secondary nozzle housing (451). A secondary overflow groove (453) is provided at the top of the secondary nozzle (451), the secondary overflow groove (453) is located below the liquid accumulation hole (412) on the drainage portion (411), a secondary drainage hole (454) communicating with the interior of the secondary nozzle housing (451) is provided at the bottom of the secondary nozzle housing (451), the secondary drainage plate (43) is inserted into the secondary drainage hole (454), the secondary drainage plate (43) is fixedly connected to the secondary nozzle (45) housing (1), and the left and right sides of the secondary drainage plate (43) are both gap-matched with the secondary drainage hole (454).

7. The horizontal tube falling film evaporator according to claim 1, characterized in that: The exhaust system (7) comprises a steam channel (44) formed by the gap between the left and right ends of the secondary liquid distributor (4) and the shell (1), and two steam outlets (11) are arranged on the top of the shell (1).

8. The horizontal tube falling film evaporator according to claim 7, characterized in that: A plurality of vertically arranged air guide pipes are arranged at the steam channel (44), and the coolant vaporized at the secondary heat exchange tube group (5) can be discharged from the air guide pipes.

9. The horizontal tube falling film evaporator according to claim 7, characterized in that: The transverse length on the secondary liquid distribution plate (41) is not less than the transverse length on the primary heat exchange tube group (3); and the transverse length of the steam channel (44) is not more than the transverse length of the primary heat exchange tube group (3).

10. The horizontal tube falling film evaporator according to claim 1, characterized in that: The circulation system (6) comprises a spherical liquid storage capsule (64) and an ejection mechanism. A liquid outlet (12) is provided at the bottom of the shell (1). The spherical liquid storage capsule (64) is arranged at the bottom of the shell (1) and covers the liquid outlet (12). Liquid coolant that has completed heat exchange at the secondary heat exchange tube group (5) can be collected in the spherical liquid storage capsule (64); the ejection mechanism can deliver the coolant in the spherical liquid storage capsule (64) to the secondary liquid distribution plate (41).

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