CN221505736U - Vertical evaporator - Google Patents

Abstract

The utility model discloses a vertical evaporator, and belongs to the technical field of heat exchangers. The bolts sequentially penetrate through the shell, the first tube plate and the tube box which are sequentially arranged from top to bottom and are fixed through nuts, locknuts are arranged on the bolts between the first tube plate and the tube box, and the locknuts are configured to be capable of fixing the first tube plate and the shell; the first tube bundle comprises a plurality of outer layer heat exchange tubes; the lower end of each outer layer heat exchange tube is connected to the first tube plate and extends into the inner cavity of the shell, and the upper end of each outer layer heat exchange tube is sealed; the lower end of the outer layer heat exchange tube is communicated with the upper chamber; the upper ends of the inner layer heat exchange tubes are open, and the inner layer heat exchange tubes are correspondingly stretched into the outer layer heat exchange tubes so that tube side medium in the inner layer heat exchange tubes can flow into the area between the inner layer heat exchange tubes and the outer layer heat exchange tubes. The vertical evaporator has small occupied area and wide application range; the tube bundle is provided with a free end, and can be subjected to thermal compensation through free expansion and contraction, so that the service life of the tube bundle is prolonged; the tube bundle is convenient to detach, and the cost is reduced.

Description

Vertical evaporator

Technical Field

The utility model relates to the technical field of heat exchangers, in particular to a vertical evaporator.

Background

The heat exchanger is one of unit equipment which is widely applied in various industries such as chemical industry, petroleum, energy sources and the like, and according to statistics, the investment of the heat exchanger in the modern chemical industry accounts for about 30 percent of the total investment of equipment, and the heat exchanger accounts for about 40 percent of the total process equipment in an oil refinery, and the sea water desalination process device almost entirely consists of the heat exchanger.

The traditional evaporator is mostly of a horizontal structure, has large volume and large occupied area, and is not applicable to sites with narrow operation space; both ends of the tube bundle of the evaporator are fixed, the thermal compensation performance is poor, and the tube bundle is easy to damage due to temperature difference stress; the tube bundle in the traditional evaporator is not detachable, and after the tube bundle is damaged, the whole evaporator needs to be replaced, so that the cost is high.

Therefore, there is a need for a vertical evaporator with small floor space, long service life of the tube bundle, and convenient disassembly, so as to solve the above technical problems in the prior art.

Disclosure of utility model

The utility model aims to provide a vertical evaporator which has small occupied area and wide application range; the tube bundle is provided with a free end, and can be subjected to thermal compensation through free expansion and contraction, so that the service life of the tube bundle is prolonged; the tube bundle is convenient to detach, and the cost is reduced.

To achieve the purpose, the utility model adopts the following technical scheme:

a vertical evaporator, comprising:

The shell is provided with a shell side inlet at the lower part and a shell side outlet at the upper part;

The first tube plate and the tube box are sequentially penetrated through the shell, the first tube plate and the tube box which are sequentially arranged from top to bottom and are fixed through nuts, locknuts are arranged on the bolts between the first tube plate and the tube box, and the locknuts are configured to be capable of fixing the first tube plate and the shell;

A first tube bundle comprising a plurality of outer heat exchange tubes; the lower end of each outer layer heat exchange tube is connected to the first tube plate and extends into the inner cavity of the shell, and the upper end of each outer layer heat exchange tube is sealed;

The second tube plate is connected in the tube box and divides the tube box into an upper chamber and a lower chamber from top to bottom, a tube side outlet is arranged on the side wall of the upper chamber, a tube side inlet is arranged on the side wall of the lower chamber, and the lower end of the outer layer heat exchange tube is communicated with the upper chamber;

The second tube bundle comprises a plurality of inner-layer heat exchange tubes, and the lower end of each inner-layer heat exchange tube is connected to the second tube plate and communicated with the lower cavity; the upper ends of the inner layer heat exchange tubes are open, and a plurality of the inner layer heat exchange tubes extend into a plurality of the outer layer heat exchange tubes in a one-to-one correspondence manner, so that tube side media in the inner layer heat exchange tubes can flow into the area between the inner layer heat exchange tubes and the outer layer heat exchange tubes.

As a preferable technical scheme of the vertical evaporator, the vertical evaporator further comprises a positioning structure, wherein the positioning structure is connected to the outer wall of the upper end of the inner heat exchange tube, and the positioning structure is used for ensuring concentricity of the inner heat exchange tube and the outer heat exchange tube.

As a preferable technical scheme of the vertical evaporator, the positioning structure is a spiral rib plate or spiral round steel; or, the positioning structure is a plurality of rib blocks, and the plurality of rib blocks are circumferentially distributed on the outer wall of the inner layer heat exchange tube at intervals.

As a preferable technical scheme of the vertical evaporator, the outer wall of the inner layer heat exchange tube is provided with a plurality of longitudinal grooves, the longitudinal grooves are arranged at intervals along the circumferential direction of the inner layer heat exchange tube, and each longitudinal groove extends along the length direction of the inner layer heat exchange tube.

As a preferable technical scheme of the vertical evaporator, a porous medium layer is arranged on the outer wall surface of the outer layer heat exchange tube.

As a preferable technical scheme of the vertical evaporator, the upper end of the outer layer heat exchange tube is sealed by adopting a tube cap structure or a flat cover structure.

As a preferable technical scheme of the vertical evaporator, a blowdown passage is formed in the first tube plate, one end of the blowdown passage is communicated with the inner cavity of the shell, and the other end of the blowdown passage is communicated with the outside.

As a preferable technical scheme of the vertical evaporator, baffle plates and/or baffle rods are arranged in the inner cavity of the shell at intervals along the height direction.

As a preferable technical scheme of the vertical evaporator, the shell comprises a first barrel, a cone section, a second barrel and a seal head which are sequentially connected, the diameter of the second barrel is larger than that of the first barrel, and the first barrel is connected with the first tube plate.

As a preferred technical solution of the vertical evaporator, the vertical evaporator further comprises a shell side outlet connection pipe, wherein the shell side outlet connection pipe is positioned inside the shell and is communicated with the shell side outlet.

The utility model provides a vertical evaporator, which has the following advantages:

1) According to the utility model, the vertical evaporator is adopted, the tube side medium enters the lower cavity from the tube side inlet, further flows upwards through the inner layer heat exchange tube, enters the outer layer heat exchange tube after reaching the top of the inner layer heat exchange tube, and is subjected to heat exchange with the shell side medium due to the temperature difference between the tube wall of the outer layer heat exchange tube and the shell side medium, the tube side medium is rapidly condensed, flows downwards to the upper cavity from the outer layer heat exchange tube after condensation, then flows out from the tube side outlet, and flows out from the shell side outlet after being evaporated, so that the heat exchange between the tube side medium and the shell side medium is realized.

2) The upper ends of the outer layer heat exchange tubes and the inner layer heat exchange tubes are free ends, and the heat compensation can be carried out through free expansion and contraction, so that the service life of the tube bundle is prolonged.

3) The shell, the first tube plate and the tube box are sequentially penetrated through from top to bottom through bolts and are fixed through nuts, so that the shell, the first tube plate and the tube box can be respectively disassembled, and further, the first tube bundle connected to the first tube plate and the second tube bundle connected to the second tube plate in the tube box can be disassembled, and the cost is reduced; the locknut is arranged on the bolt between the first tube plate and the tube box, so that the first tube bundle on the first tube plate is conveniently fixed before the second tube bundle is installed, the second tube bundle is conveniently installed and disassembled, the first tube plate and the shell are conveniently disassembled, the tightness of a shell side is ensured not to be influenced by disassembling the tube box, the first tube bundle and the second tube bundle are relatively independent to be disassembled and maintained, and the cost is further reduced; in addition, when the shell side is subjected to a pressure test, the locknut is screwed, a test compression ring is not required, and materials and processing cost are saved.

Drawings

Fig. 1 is a schematic structural view of a vertical evaporator according to an embodiment of the present utility model;

FIG. 2 is a schematic illustration of the connection of a shell, a first tube sheet and a tube cassette provided in an embodiment of the present utility model;

FIG. 3 is a front view of a first positioning structure, an inner heat exchange tube and an outer heat exchange tube according to an embodiment of the present utility model;

FIG. 4 is a top view of a first positioning structure, an inner heat exchange tube and an outer heat exchange tube according to an embodiment of the present utility model;

FIG. 5 is a perspective view of a second positioning structure, an inner heat exchange tube and an outer heat exchange tube according to an embodiment of the present utility model;

FIG. 6 is a schematic view of a drain passage according to an embodiment of the present utility model;

FIG. 7 is a front view of a portion of the structure of the inner heat exchange tubes in the second tube bundle according to the present utility model;

FIG. 8 is a partial structural plan view of the inner heat exchange tubes in the second tube bundle according to the present utility model;

FIG. 9 is a front view of a portion of the structure of the outer heat exchange tubes in the first tube bundle according to an embodiment of the present utility model;

Fig. 10 is a schematic structural diagram of a fixing tool according to an embodiment of the present utility model.

Reference numerals:

1. A housing; 2. a first tube sheet; 21. a sewage discharge passage; 3. a first tube bundle; 4. a tube box; 41. an upper chamber; 411. a tube side outlet; 42. a lower chamber; 421. a tube side inlet; 5. a locknut; 6. a second tube sheet; 7. a second tube bundle; 8. a baffle plate; 9. a shell side outlet connection pipe; 10. a positioning structure;

100. And (5) fixing the tool.

Detailed Description

In order to make the technical problems solved, the technical scheme adopted and the technical effects achieved by the utility model more clear, the technical scheme of the utility model is further described below by a specific embodiment in combination with the attached drawings.

In the description of the present utility model, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are orientation or positional relationships based on those shown in the drawings, merely for convenience of description and simplicity of operation, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the utility model. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for distinguishing between them.

As shown in fig. 1 and 2, the present embodiment provides a vertical evaporator comprising a shell 1, a first tube sheet 2, a tube box 4, a first tube bundle 3, a second tube sheet 6, and a second tube bundle 7, wherein a lower portion of the shell 1 is provided with a shell side inlet, and an upper portion of the shell 1 is provided with a shell side outlet; bolts sequentially penetrate through the shell 1, the first tube plate 2 and the tube box 4 which are sequentially arranged from top to bottom and are fixed through nuts, locknuts 5 are arranged on the bolts between the first tube plate 2 and the tube box 4, and the locknuts 5 are configured to be capable of fixing the first tube plate 2 and the shell 1; the first tube bundle 3 comprises a plurality of outer heat exchange tubes; the lower end of each outer layer heat exchange tube is connected to the first tube plate 2 and extends into the inner cavity of the shell 1, and the upper end of each outer layer heat exchange tube is sealed; the second tube plate 6 is connected in the tube box 4 and divides the tube box 4 into an upper chamber 41 and a lower chamber 42 from top to bottom, a tube side outlet 411 is arranged on the side wall of the upper chamber 41, a tube side inlet 421 is arranged on the side wall of the lower chamber 42, and the lower end of the outer layer heat exchange tube is communicated with the upper chamber 41; the second tube bundle 7 comprises a plurality of inner-layer heat exchange tubes, and the lower end of each inner-layer heat exchange tube is connected to the second tube plate 6 and communicated with the lower chamber 42; the upper ends of the inner layer heat exchange tubes are open, and the inner layer heat exchange tubes are correspondingly stretched into the outer layer heat exchange tubes so that tube side medium in the inner layer heat exchange tubes can flow into the area between the inner layer heat exchange tubes and the outer layer heat exchange tubes.

By adopting the vertical evaporator, a tube side medium enters the lower cavity from the tube side inlet, flows upwards through the inner layer heat exchange tube, enters the inner layer heat exchange tube after reaching the top of the inner layer heat exchange tube, and is subjected to heat exchange between the tube side medium and the shell side medium due to the temperature difference between the tube wall of the outer layer heat exchange tube and the shell side medium, the tube side medium is rapidly condensed, flows downwards to the upper cavity 41 through the outer layer heat exchange tube after condensation, flows out through the tube side outlet, and flows out through the shell side outlet after being evaporated, so that heat exchange between the tube side medium and the shell side medium is realized. The upper ends of the outer layer heat exchange tubes and the inner layer heat exchange tubes are free ends, and the heat compensation can be carried out through free expansion and contraction, so that the service life of the tube bundle is prolonged. The shell 1, the first tube plate 2 and the tube box 4 which are sequentially arranged from top to bottom are sequentially penetrated through the bolts and are fixed through the nuts, so that the shell 1, the first tube plate 2 and the tube box 4 can be respectively disassembled, the first tube bundle 3 connected to the first tube plate 2 and the second tube bundle 7 connected to the second tube plate 6 in the tube box 4 can be disassembled, and the cost is reduced; the locknut 5 is arranged on the bolt between the first tube plate 2 and the tube box 4, the locknut 5 is convenient for fixing the first tube bundle 3 on the first tube plate 2 before the second tube bundle 7 is installed, is convenient for installing and dismantling the second tube bundle 7, and when the second tube bundle 7 is convenient to dismantle, the first tube plate 2 and the shell 1 are fastened through the locknut 5, so that the tightness of a shell side is not influenced by the dismantling of the tube box 4, the first tube bundle 3 and the second tube bundle 7 are relatively independent to dismantle and maintain, and the cost is further reduced; in addition, when the shell side is subjected to a pressure test, the locknut 5 is screwed, a test compression ring is not required, and materials and processing cost are saved.

The tube box 4 is divided into an upper chamber 41 and a lower chamber 42, and steam (or other heating fluid) entering from a tube side inlet of the lower chamber 42 continuously heats condensate flowing out of the upper chamber 41, so that the tube side medium is prevented from being frozen. Specifically, in this embodiment, the tube box 4 is arranged in sections, and is divided into an upper tube box and a lower tube box, the second tube sheet 6 is connected between the upper tube box and the lower tube box, so that the tube box 4 is divided into an upper chamber 41 and a lower chamber 42, after the second tube bundle 7, the second tube sheet 6 and the upper tube box are welded, the first tube bundle 3 is assembled, and after the assembly is completed, the lower tube box is welded with the second tube sheet 6, so that the second tube sheet 6 also plays the role of a separation partition plate while supporting the inner layer heat exchange tube, the tube box 4 is divided into the upper chamber 41 and the lower chamber 42, and a tube side medium enters from the lower chamber 42, flows to the upper chamber 41 after heat exchange is completed, and flows out through a tube side outlet. The bottom of the pipe box 4 is provided with a large flat cover structure, so that the equipment height can be effectively reduced, and the space can be saved; if not limited by the occupied area, the sealing head structure can also be arranged. Further, the large flat cover structure at the bottom of the pipe box 4 is welded with the simple support, and plays a role of supporting equipment.

When inner heat exchange tube and outer heat exchange tube are assembled, in order to improve assembly efficiency, need adopt fixed frock 100 to fix second tube bank 7, through with inner heat exchange tube and fixed frock spot welding, with the rigidity of increase inner heat exchange tube, after the whole installation of second tube bank 7 is accomplished, can tear down fixed frock 100, this fixed frock 100 can increase the concentricity between inner heat exchange tube and the outer heat exchange tube, reduce outer heat exchange tube inner wall wearing and tearing, convenient to detach improves the packaging efficiency of tube bank. As shown in fig. 10, the fixing tool 100 may be a support plate, and a plurality of fixing through holes are formed in the support plate, wherein the diameters of the fixing through holes are the same as the outer diameter of the inner heat exchange tube, or the diameters of the fixing through holes are slightly larger than the outer diameter of the inner heat exchange tube, and the arrangement mode of the fixing through holes needs to be as follows: after the supporting plate is cut into the strip-shaped plates along the circle center connecting line of the fixing through holes of each row or each column, the strip-shaped plates can be sequentially clamped on two sides of the inner layer heat exchange tubes of each row or each column, and the inner layer heat exchange tubes can be located in the fixing through holes and spot-welded with the supporting plate.

Specifically, the first flange that the lower extreme of casing 1 is connected, and the upper end of tube case 4 is connected with the second flange, and the tip of first tube sheet 2 sets up to the convex shoulder structure, has seted up the through-hole structure on the convex shoulder structure, and the flange bolt hole on through-hole structure, the first flange is corresponding along vertical direction with the flange bolt hole on the second flange to the flange bolt hole on the first flange, the flange bolt hole on through-hole structure and the second flange are worn to locate to the bolt, and fix through the nut.

If the upper end of the inner layer heat exchange tube is suspended, vibration of the inner layer heat exchange tube is caused in the tube side medium flowing process. In order to solve the above problems, preferably, the vertical evaporator further comprises a positioning structure 10, wherein the positioning structure 10 is connected to an outer wall of an upper end of the inner heat exchange tube, and the positioning structure 10 is used for ensuring concentricity of the inner heat exchange tube and the outer heat exchange tube, so as to avoid vibration of the inner heat exchange tube during flowing of the tube side medium in the inner heat exchange tube.

Based on the angle that the positioning structure 10 is as simple as possible, is convenient to manufacture, is convenient to assemble and disassemble between the inner layer heat exchange tube and the outer layer heat exchange tube, cannot block the flow of tube side medium and ensures the concentricity of the inner layer heat exchange tube and the outer layer heat exchange tube, specifically, as shown in fig. 5, the positioning structure 10 is a spiral rib plate or spiral round steel; or, as shown in fig. 3 and 4, the positioning structure 10 is a plurality of rib blocks, and the plurality of rib blocks are circumferentially distributed on the outer wall of the inner layer heat exchange tube at intervals. Preferably, in this embodiment, the positioning structure 10 is a plurality of rib blocks, and the plurality of rib blocks are circumferentially distributed on the outer wall of the inner layer heat exchange tube at intervals, compared with the spiral rib plate or spiral round steel, the structure shape of the rib blocks is simpler, the welding difficulty is low, and the rib blocks are not easy to deform after welding. Further preferably, the upper ends and the lower ends of the rib blocks are smoothly transited, so that the outer heat exchange tube can be prevented from being scratched when the inner heat exchange tube is disassembled and assembled. It should be noted that, in other embodiments, factors such as manufacturing difficulty and cost of the apparatus may be comprehensively considered, and other structural forms of the positioning structure 10 may be selected.

The basic working principle of the heat exchanger is that the tube side medium in the inner layer heat exchange tube flows into the outer layer heat exchange tube to release heat, and the heat is condensed and flows to the tube side outlet. Preferably, as shown in fig. 7 and 8, in this embodiment, the outer wall of the inner layer heat exchange tube is provided with a plurality of longitudinal grooves, the plurality of longitudinal grooves are arranged at intervals along the circumferential direction of the inner layer heat exchange tube, and each longitudinal groove extends along the length direction of the inner layer heat exchange tube, compared with a common light pipe, the longitudinal grooves can accelerate the falling of condensate, reduce the thermal resistance of the liquid film, and thus improve the condensation efficiency of the medium on the tube side. In order to be welded with the second tube plate 6 conveniently, a section of light pipe is reserved at the lower end of the inner layer heat exchange tube.

In order to improve the heat exchange efficiency of the shell side, as shown in fig. 9, preferably, in this embodiment, a porous medium layer is disposed on the outer wall surface of the outer heat exchange tube, that is, a layer of metal powder is sintered on the outer surface of the outer heat exchange tube to form a porous medium layer. Compared with a common light pipe, the porous medium layer can form a plurality of nucleate boiling centers, so that the film boiling is changed into the nucleate boiling, the heat transfer coefficient is greatly improved, and the evaporation of the shell side medium is accelerated. Also, to facilitate welding with the first tube sheet 2, a section of light pipe is left at the lower end of the outer layer heat exchange tube.

In order to prevent the tube side medium and the shell side medium from being mixed, the upper end of the outer layer heat exchange tube is required to be provided with a corresponding sealing structure, and the upper end of the outer layer heat exchange tube is illustratively sealed by adopting a tube cap structure or sealed by adopting a flat cover structure. The flat cover structure is welded with the upper end of the heat exchange tube, and the outer layer heat exchange tube has smaller size, the corresponding flat cover structure has smaller size, more quantity and large processing difficulty; and the welding seam is a fillet welding seam, so that the welding difficulty is high, the welding quality is not easy to ensure, and the welding seam is suitable for occasions with larger diameters of the outer heat exchange tubes. The pipe cap structure is an outsourcing piece, secondary processing is not needed, butt welding is conducted on the pipe cap structure and the outer layer heat exchange pipe, the welding difficulty is small, and compared with the flat cover structure, the pipe cap structure is more suitable for the outer layer heat exchange pipe with the small diameter. In order to ensure the tightness of the upper end of the outer layer heat exchange tube, a welding joint between the flat cover structure or the tube cap structure and the outer layer heat exchange tube is subjected to 100% PT detection after welding, and the welding quality is checked.

Preferably, as shown in fig. 6, the first tube plate 2 is provided with a blow-down passage 21, one end of the blow-down passage 21 is communicated with the inner cavity of the shell 1, the other end of the blow-down passage is communicated with the outside, a blow-down pipe is connected to the outside of the first tube plate 2, the blow-down passage 21 is communicated with the outside through the blow-down pipe, the blow-down outlet is located at the lowest point of the shell side, so that the shell side residual medium is conveniently and smoothly discharged, and the retention of the shell side residual medium is small.

As shown in fig. 1, baffles 8 and/or rods are arranged in the inner cavity of the housing 1 at intervals in the height direction. The baffle plate 8 can limit the upper part of the outer heat exchange tube in the horizontal direction, so that the outer heat exchange tube is prevented from shaking along the horizontal direction.

In order to ensure sufficient evaporation space for the shell side medium, the length of the shell 1 of the shell side needs to be much longer than the length of the outer heat exchange tube. Preferably, the shell 1 comprises a first barrel, a cone section, a second barrel and an end socket which are sequentially connected, the diameter of the second barrel is larger than that of the first barrel, the first barrel is connected with the first tube plate 2, and by adopting the shell 1 with the variable diameter, the evaporation space of shell side media can be increased, the height of the vertical evaporator can be effectively shortened, and the height space is saved.

Preferably, the vertical evaporator further comprises a shell side outlet nipple 9, the shell side outlet nipple 9 being located inside the shell 1 and communicating with the shell side outlet. The shell side outlet connecting pipe 9 is arranged in an inward extending mode, an elbow which is opened upwards is arranged at the center of the shell 1, and the elbow is communicated with the shell side outlet through a straight pipe, so that the gas flow at the end socket can be quickened, and long-time accumulation of media is effectively avoided.

The foregoing is merely exemplary of the present utility model, and those skilled in the art should not be considered as limiting the utility model, since modifications may be made in the specific embodiments and application scope of the utility model in light of the teachings of the present utility model.

Claims (10)

1. A vertical evaporator, comprising:

The shell comprises a shell (1), wherein a shell side inlet is formed in the lower part of the shell (1), and a shell side outlet is formed in the upper part of the shell (1);

The device comprises a first tube plate (2) and a tube box (4), wherein bolts sequentially penetrate through the shell (1), the first tube plate (2) and the tube box (4) which are sequentially arranged from top to bottom and are fixed through nuts, locknuts (5) are arranged on the bolts between the first tube plate (2) and the tube box (4), and the locknuts (5) are configured to be capable of fixing the first tube plate (2) and the shell (1);

A first tube bundle (3) comprising a plurality of outer heat exchange tubes; the lower end of each outer layer heat exchange tube is connected to the first tube plate (2) and extends into the inner cavity of the shell (1), and the upper end of each outer layer heat exchange tube is sealed;

The second tube plate (6) is connected in the tube box (4) and divides the tube box (4) into an upper chamber (41) and a lower chamber (42) from top to bottom, a tube side outlet (411) is arranged on the side wall of the upper chamber (41), a tube side inlet (421) is arranged on the side wall of the lower chamber (42), and the lower end of the outer layer heat exchange tube is communicated with the upper chamber (41);

The second tube bundle (7) comprises a plurality of inner-layer heat exchange tubes, the lower end of each inner-layer heat exchange tube is connected to the second tube plate (6) and communicated with the lower chamber (42); the upper ends of the inner layer heat exchange tubes are open, and a plurality of the inner layer heat exchange tubes extend into a plurality of the outer layer heat exchange tubes in a one-to-one correspondence manner, so that tube side media in the inner layer heat exchange tubes can flow into the area between the inner layer heat exchange tubes and the outer layer heat exchange tubes.

2. A vertical evaporator according to claim 1, further comprising a positioning structure (10), wherein the positioning structure (10) is connected to an outer wall of an upper end of the inner heat exchange tube, and wherein the positioning structure (10) is configured to ensure concentricity of the inner heat exchange tube and the outer heat exchange tube.

3. A vertical evaporator according to claim 2, wherein the positioning structure (10) is a spiral rib plate or a spiral round steel; or, the positioning structure (10) is a plurality of rib blocks, and the plurality of rib blocks are circumferentially distributed on the outer wall of the inner-layer heat exchange tube at intervals.

4. A vertical evaporator according to any one of claims 1 to 3, wherein the outer wall of the inner heat exchange tube is provided with a plurality of longitudinal grooves which are arranged at intervals in the circumferential direction of the inner heat exchange tube, and each of the longitudinal grooves extends in the longitudinal direction of the inner heat exchange tube.

5. A vertical evaporator according to any one of claims 1 to 3, wherein a porous medium layer is provided on an outer wall surface of the outer heat exchange tube.

6. A vertical evaporator according to any one of claims 1 to 3 wherein the upper ends of the outer heat exchange tubes are sealed with a tube cap structure or with a flat cover structure.

7. A vertical evaporator according to any one of claims 1-3, characterized in that the first tube sheet (2) is provided with a blow-down passage (21), one end of the blow-down passage (21) is communicated with the inner cavity of the shell (1), and the other end is communicated with the outside.

8. A vertical evaporator according to any one of claims 1-3, characterized in that the inner cavity of the housing (1) is provided with baffles (8) and/or rods at intervals in the height direction.

9. A vertical evaporator according to any one of claims 1-3, wherein the housing (1) comprises a first cylinder, a cone section, a second cylinder and a head, which are connected in sequence, the diameter of the second cylinder being larger than the diameter of the first cylinder, the first cylinder being connected to the first tube sheet (2).

10. A vertical evaporator according to any of claims 1-3, further comprising a shell side outlet nipple (9), said shell side outlet nipple (9) being located inside the housing (1) and communicating with the shell side outlet.