Extrusion shunting sleeve type vacuum heat pipe heat exchanger

Abstract

The utility model discloses an extrusion shunting sleeve type vacuum heat pipe heat exchanger which is composed of a plurality of water sleeve type gravity heat pipes, and each water sleeve type gravity heat pipe comprises a base pipe, a sleeve, a sleeve inlet water pipe, a sleeve outlet water pipe, a sleeve lower sealing head and a sleeve upper sealing head. Two circulation cavities are formed between a base pipe and a sleeve of a cooling water heat exchange part of the water sleeve type gravity heat pipe, the two circulation cavities are communicated through a communication cavity, and cooling water firstly descends to a sleeve lower end socket area of the water sleeve type gravity heat pipe through a sleeve inlet water pipe, then is folded upwards to a sleeve upper end socket area and flows out through a sleeve outlet water pipe. The water jacket type gravity assisted heat pipe without the lower connecting pipe for countercurrent flow heat exchange is adopted, all welding seams of the heat pipe are positive welding seams, the leakage situation caused by welding seam damage can be found and treated in time, overall isolation of the pipe row is not needed, and the cost is reduced. The problem that due to the fact that defects of water side welding points of an existing flue gas heat exchanger cannot be treated, tube bundles need to stop running is solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of heat pipe heat exchange equipment, in particular to an extruded split-flow sleeve type vacuum heat pipe heat exchanger. Background Art

[0002] At present, flue gas heat exchangers are widely used in low-temperature electrostatic precipitator technology. By configuring a flue gas heat exchanger in front of the electrostatic precipitator, the flue gas temperature at the inlet of the electrostatic precipitator is reduced to below the acid dew point, so that most of the SO3 in the flue gas is condensed in the flue gas heat exchanger to form sulfuric acid mist, which adheres to the surface of dust particles and is neutralized by alkaline substances, greatly reducing the resistivity of the dust, avoiding the back corona phenomenon, improving the dust removal efficiency, removing most of the SO3 in the flue gas, and achieving better environmental benefits.

[0003] Conventional serpentine tube wall-type flue gas heat exchangers are prone to tube bundle leakage during use, and the main factors causing leakage include wear leakage, corrosion leakage, and stress damage leakage, among which wear leakage is the most common. In a high-dust environment, the long-term erosion of the heat exchange tube bundle by dust will cause wear of the heat exchange tube, but conventional uniform wear can guarantee a service life of at least 10-20 years for the heat exchange tube under normal wall thickness and designed flue gas conditions. Therefore, wear leakage is mainly caused by the unevenness of the dust gas-solid two-phase flow. In other words, the actual cause of the conventional shell and tube heat exchanger to stop operating is often several tube bundles that are severely worn. Once the leakage is not discovered, the cooling water will continue to leak into the flue gas, causing dust accumulation, blockage, and even serious blockage problems, resulting in low availability of the overall equipment.

[0004] Compared to conventional pre-dust collector serpentine tube interlayer flue gas heat exchangers, gravity heat pipe flue gas heat exchangers transfer heat through the evaporation and condensation of the working fluid within a fully enclosed vacuum tube. This system offers a range of advantages, including extremely high thermal conductivity, excellent isothermal properties, the ability to arbitrarily adjust the heat transfer area between the hot and cold sides, long-distance heat transfer capability, and temperature control. Vacuum heat pipe heat exchangers also feature near-zero leakage, and minor wear and leakage from heat pipes within a heat pipe group will not affect the normal heat transfer of other heat pipes. Consequently, vacuum heat pipe heat exchange technology has been widely used in flue gas waste heat utilization projects in recent years.

[0005] Chinese patent application number CN201621471918.5 discloses a low-temperature economizer with a glass-lined heat pipe structure. The heat pipe comprises a smoke box and a heat collecting box separated by a tube sheet channel. The heat collecting box includes heat pipes, a water jacket, a lower connecting pipe, an upper connecting pipe, a soft water inlet, a soft water outlet, and a connecting pipe end cap. Multiple heat pipes extend from bottom to top through the tube sheet channel and the lower connecting pipe, with their cold ends extending into the water jacket. The water jackets are connected in parallel between the upper and lower connecting pipes and communicate with them. This utility model provides a low-temperature economizer with low steel usage, high pressure bearing capacity, high heat exchange efficiency, and a long service life. However, this utility model suffers from cross-flow heat exchange with the flue gas, isothermal heat exchange between the tubes, and reduced heat exchange temperature differences, resulting in poor heat exchange performance. Furthermore, there are numerous welds, and any weld defects are difficult to repair. Chinese patent application number CN200520069206.6 discloses a leak-proof, corrosion-resistant, and easy-to-clean separate-tube flue gas cooler for cooling raw flue gas in boiler flue gas desulfurization systems. This device addresses the problems of raw flue gas leakage, dew point corrosion, and dust accumulation in heat exchangers. The heat pipe flue gas cooler comprises a housing, a heat pipe disposed within the housing, a sleeve disposed externally, a weld block fixedly attached to the heat pipe, and a central orifice plate serving as a separator within the housing. The central orifice plate and the weld block utilize a welded sealing structure. This solution maintains essentially the same water flow temperature within each water jacket, resulting in cross-convection heat exchange with the flue gas. This solution presents the problem of cross-heat exchange due to a small temperature difference. Furthermore, the system suffers from numerous welds, making weld point problems difficult to address.

[0006] In summary, current heat pipe heat exchangers generally have the problem of having many welding points on the water side and high welding quality control requirements. Utility Model Content

[0007] To solve the above technical problems, the utility model provides an extruded split-flow sleeve-type vacuum heat pipe heat exchanger. While adopting a water-jacketed tube and heat pipe for efficient heat exchange, the heat exchanger eliminates the lower connecting tube, thereby avoiding the problem of tube bundle failure caused by weld tearing under harsh working conditions or welding stress. At the same time, the increased flow of cold water also makes the heat exchange more sufficient.

[0008] The technical solution of the utility model is as follows:

[0009] An extruded split-flow jacketed vacuum heat pipe heat exchanger comprises a shell, a cooling water inlet header, a cooling water outlet header, and a heat pipe heat exchanger connecting the cooling water inlet header and the cooling water outlet header. The heat pipe heat exchanger disposed within the shell comprises a plurality of water-jacketed gravity heat pipes. A partition is provided within the shell cavity to divide the shell into a cooling water heat exchange chamber and a flue gas heat exchange chamber.

[0010] The water-jacket-type gravity heat pipe includes: a base tube, a jacket, a jacket inlet water pipe, a jacket outlet water pipe, a jacket lower head and a jacket upper head; the base tube of the heat pipe is filled with a working medium, the cooling water heat exchange part of the water-jacket-type gravity heat pipe is arranged in a cooling water heat exchange cavity, and the flue gas heat exchange part is arranged in the flue gas heat exchange cavity. Two flow cavities are formed between the base tube and the jacket of the cooling water heat exchange part, and a connecting cavity is provided at the bottom of the two flow cavities for communication. The cooling water first flows downward to the jacket lower head area of ​​the water-jacket-type gravity heat pipe through the jacket inlet water pipe, then turns upward to the jacket upper head area, and flows out through the jacket outlet water pipe.

[0011] Furthermore, the cross section of the base tube is circular, the cross section of the sleeve is elliptical, the base tube passes through the sleeve, and the outer wall of the base tube is tangent to the inner wall of the sleeve to form two flow cavities.

[0012] Furthermore, the cross-sections of the inlet water pipe and the outlet water pipe are elliptical.

[0013] Furthermore, a gap is left between the top of the casing and the base pipe.

[0014] Furthermore, the gap is 0.5-1 mm.

[0015] Furthermore, fins are provided outside the base tube of the flue gas heat exchange part.

[0016] Furthermore, the fin is a full-blade spiral fin structure, a U-shaped toothed spiral fin structure or a V-shaped toothed spiral fin structure.

[0017] Furthermore, when the extruded split-flow sleeve-type vacuum heat pipe heat exchanger is arranged in a vertical flue, it is arranged in an inclined manner with a bevel angle of 10-15°.

[0018] Furthermore, the heat pipe heat exchanger is composed of several heat pipe heat exchange modules, the heat pipe heat exchange module is composed of several heat pipe groups, and a single row of heat pipe groups is composed of several water-jacketed gravity heat pipes connected in series; the water-jacketed gravity heat pipes are connected in series through jacket inlet water pipes and jacket outlet water pipes to obtain a heat pipe group, and the heat pipe groups are connected in parallel through cooling water inlet headers and cooling water outlet headers to obtain a heat pipe heat exchange module.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] 1. The present invention provides an extruded split-flow sleeve-type vacuum heat pipe heat exchanger, which adopts a water-jacketed gravity heat pipe for countercurrent heat exchange without a lower connecting pipe. By eliminating the lower connecting pipe, all welds of the heat pipe are positive welds, which can promptly detect and handle leaks caused by weld damage, eliminating the need to isolate the entire tube bank. This solves the problem of existing flue gas heat exchangers having defects in the water-side welding points that cannot be handled, resulting in the need to stop the operation of the tube bank. The present invention can avoid the problem of tube bundle failure caused by weld tearing under harsh working conditions or welding stress. At the same time, the present invention designs the cross-section of the sleeve to be elliptical, with the base pipe passing through the sleeve, and making the outer wall of the base pipe tangent to the inner wall of the sleeve to form two flow cavities, thereby forming a double flow channel for countercurrent heat exchange, which increases the flow of cooling water, improves heat exchange efficiency, and makes heat exchange more sufficient.

[0021] 2. In the present invention, by providing a gap between the top of the sleeve with an elliptical cross-section and the base pipe, the air retained in the sleeve before startup, the small amount of gas carried by the cooling water, and the steam generated by the overheating of the feed water can be smoothly discharged from the heat exchanger, thereby reducing the resistance of the water channel and ensuring the efficiency of heat exchange.

[0022] 3. In the present invention, the heat pipe flue gas heat exchanger used has the characteristic of near-zero leakage, which increases the service life of the heat exchanger and significantly enhances the stability of the heat exchanger. In addition, the water-jacketed gravity heat pipe used has high heat exchange efficiency and excellent pressure resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A cross-sectional view of a water-jacketed gravity heat pipe in an extruded split-flow jacketed vacuum heat pipe heat exchanger provided by the present invention;

[0024] Figure 2 A schematic diagram of the cooling water flow path of the cooling water heat exchange portion of a water-jacketed gravity heat pipe in an extruded split-flow jacketed vacuum heat pipe heat exchanger provided by the present invention;

[0025] Figure 3 This is a schematic structural diagram of a single water-jacketed gravity heat pipe in an extruded split-flow jacketed vacuum heat pipe heat exchanger provided by the present invention;

[0026] Figure 4 A cross-sectional view of the cooling water heat exchange portion of a water-jacketed gravity heat pipe in an extruded split-flow jacketed vacuum heat pipe heat exchanger provided by the present invention;

[0027] Figure 5 A schematic diagram of an extruded split-flow sleeve-type vacuum heat pipe heat exchanger provided by the present invention arranged in a horizontal flue;

[0028] Figure 6A schematic diagram of an extruded split-flow sleeve-type vacuum heat pipe heat exchanger provided by the utility model arranged in a vertical flue;

[0029] Figure 7 This is a schematic diagram of a full-blade spiral fin structure in the present invention;

[0030] Figure 8 This is a schematic diagram of a U-shaped toothed spiral fin structure in the present invention;

[0031] Figure 9 This is a schematic diagram of the V-shaped toothed spiral fin structure in the present invention.

[0032] In the figure, 1. shell; 2. heat pipe heat exchanger; 3. cooling water inlet header; 4. cooling water outlet header; 5. partition; 6. cooling water heat exchange chamber; 7. flue gas heat exchange chamber; 8. base pipe; 9. casing; 11. casing inlet water pipe; 12. casing outlet water pipe; 13. fin; 14. casing lower head; 15. casing upper head; 16. circulation chamber; 17. connecting chamber. DETAILED DESCRIPTION

[0033] Below in conjunction with preferred embodiment, and referring to attached Figure 1-9 , to further illustrate the present invention, the endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values; for numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be deemed to be specifically disclosed herein.

[0034] Example 1

[0035] This embodiment provides an extruded split-flow shell-and-tube vacuum heat pipe heat exchanger, such as Figure 5 As shown, the extruded split-flow jacketed vacuum heat pipe heat exchanger of this embodiment is arranged in a horizontal flue. The extruded split-flow jacketed vacuum heat pipe heat exchanger includes a shell 1, a cooling water inlet header 3, a cooling water outlet header 4, and a heat pipe heat exchanger 2 connecting the cooling water inlet header 3 and the cooling water outlet header 4. The heat pipe heat exchanger 2 arranged in the shell 1 is composed of a plurality of water-jacketed gravity heat pipes. The inner cavity of the shell 1 is provided with a partition 5 to divide the shell 1 into a cooling water heat exchange chamber 6 and a flue gas heat exchange chamber 7.

[0036] like Figure 3As shown, the water-jacketed gravity heat pipe includes: a base pipe 8, a jacket 9, a jacket inlet water pipe 11, a jacket outlet water pipe 12, a jacket lower head 14 and a jacket upper head 15; the heat pipe base pipe 8 is filled with a working medium, the cooling water heat exchange part of the water-jacketed gravity heat pipe is arranged in the cooling water heat exchange cavity 6, and the flue gas heat exchange part is arranged in the flue gas heat exchange cavity 7. Two flow cavities 16 are formed between the base pipe 8 and the jacket 9 of the cooling water heat exchange part, and a connecting cavity 17 is provided at the bottom of the two flow cavities 16 for communication, as shown in FIG. Figure 2 As shown, the cooling water first flows downward through the jacket inlet water pipe 11 to the jacket lower head 14 area of ​​the water-jacket type gravity heat pipe, then turns upward to the jacket upper head 15 area, and flows out through the jacket outlet water pipe 12.

[0037] like Figure 1 As shown, the cross section of the base tube 8 of this embodiment is circular, and the cross section of the sleeve 9 is elliptical. The base tube 8 passes through the sleeve 9, and the outer wall of the base tube 8 is tangent to the inner wall of the sleeve 9 to form two flow cavities 16.

[0038] like Figure 1 As shown, the cross-sections of the casing inlet water pipe 11 and the casing outlet water pipe 12 of this embodiment are elliptical.

[0039] In this embodiment, Figure 4 As shown, a gap is left between the top of the sleeve 9 and the base pipe 8, and the gap is 0.5 mm. The air retained in the sleeve before startup, the small amount of gas carried by the cooling water, and the steam generated by the superheated feed water can be smoothly discharged from the heat exchanger to reduce the resistance of the water channel and ensure the efficiency of heat exchange.

[0040] In this embodiment, the base tube 8 of the flue gas heat exchange portion is provided with fins 13. The heat exchange area can be increased by providing the fins 13. Figure 7 As shown, the fin 13 of this embodiment is a full-blade spiral fin structure.

[0041] In this embodiment, the heat pipe heat exchanger is composed of several heat pipe heat exchange modules, which are composed of several heat pipe groups. A single row of heat pipe groups is composed of several water-jacketed gravity heat pipes connected in series. The water-jacketed gravity heat pipes are connected in series through the jacket inlet water pipe 11 and the jacket outlet water pipe 12 to obtain a heat pipe group. The heat pipe groups are connected in parallel through the cooling water inlet header 3 and the cooling water outlet header 4 to obtain a heat pipe heat exchange module.

[0042] Example 2

[0043] This embodiment provides an extruded split-flow shell-and-tube vacuum heat pipe heat exchanger, such as Figure 6As shown, the extruded split-flow sleeve-type vacuum heat pipe heat exchanger of this embodiment is arranged in a vertical flue and is arranged in an inclined manner, wherein the inclination angle is 15°. The flue gas flows into the heat pipe heat exchanger 2 from the lower flue inlet and then flows out from the upper part. The heat pipe heat exchanger 2 is arranged in an inclined manner. The extruded split-flow sleeve-type vacuum heat pipe heat exchanger includes a shell 1, a cooling water inlet header 3, a cooling water outlet header 4, and a heat pipe heat exchanger 2 connecting the cooling water inlet header 3 and the cooling water outlet header 4. The heat pipe heat exchanger 2 arranged in the shell 1 is composed of a plurality of water-jacket-type gravity heat pipes. The inner cavity of the shell 1 is provided with a partition 5 to divide the shell 1 into a cooling water heat exchange chamber 6 and a flue gas heat exchange chamber 7 in the upper and lower parts.

[0044] like Figure 3 As shown, the water-jacketed gravity heat pipe includes: a base pipe 8, a jacket 9, a jacket inlet water pipe 11, a jacket outlet water pipe 12, a jacket lower head 14 and a jacket upper head 15; the heat pipe base pipe 8 is filled with a working medium, the cooling water heat exchange part of the water-jacketed gravity heat pipe is arranged in the cooling water heat exchange cavity 6, and the flue gas heat exchange part is arranged in the flue gas heat exchange cavity 7. Two flow cavities 16 are formed between the base pipe 8 and the jacket 9 of the cooling water heat exchange part, and a connecting cavity 17 is provided at the bottom of the two flow cavities 16 for communication, as shown in FIG. Figure 2 As shown, the cooling water first flows downward through the jacket inlet water pipe 11 to the jacket lower head 14 area of ​​the water-jacket type gravity heat pipe, then turns upward to the jacket upper head 15 area, and flows out through the jacket outlet water pipe 12;

[0045] like Figure 1 As shown, the cross section of the base tube 8 of this embodiment is circular, and the cross section of the sleeve 9 is elliptical. The base tube 8 passes through the sleeve 9, and the outer wall of the base tube 8 is tangent to the inner wall of the sleeve 9 to form two flow cavities 16.

[0046] like Figure 1 As shown, the cross-sections of the casing inlet water pipe 11 and the casing outlet water pipe 12 of this embodiment are elliptical.

[0047] like Figure 4 As shown, in this embodiment, a gap of 1 mm is left between the top of the sleeve 9 and the base pipe 8, which can allow the air retained in the sleeve before startup, a small amount of gas carried by the cooling water, and the steam generated by the superheated feed water to be smoothly discharged from the heat exchanger, thereby reducing the resistance of the water channel and ensuring the efficiency of heat exchange.

[0048] In this embodiment, the base tube 8 of the flue gas heat exchange portion is provided with fins 13. The heat exchange area can be increased by providing the fins 13. Figure 8 As shown, the fin 13 of this embodiment is a U-shaped toothed spiral fin structure.

[0049] In this embodiment, the heat pipe heat exchanger is composed of several heat pipe heat exchange modules, which are composed of several heat pipe groups. A single row of heat pipe groups is composed of several water-jacketed gravity heat pipes connected in series. The water-jacketed gravity heat pipes are connected in series through the jacket inlet water pipe 11 and the jacket outlet water pipe 12 to obtain a heat pipe group. The heat pipe groups are connected in parallel through the cooling water inlet header 3 and the cooling water outlet header 4 to obtain a heat pipe heat exchange module.

[0050] Example 3

[0051] This embodiment provides an extruded split-flow shell-and-tube vacuum heat pipe heat exchanger, such as Figure 6 As shown, the extruded split-flow sleeve-type vacuum heat pipe heat exchanger of this embodiment is arranged in a vertical flue and is arranged in an inclined manner, wherein the inclination angle is 10°. The extruded split-flow sleeve-type vacuum heat pipe heat exchanger includes a shell 1, a cooling water inlet header 3, a cooling water outlet header 4, and a heat pipe heat exchanger 2 connecting the cooling water inlet header 3 and the cooling water outlet header 4. The heat pipe heat exchanger 2 arranged in the shell 1 is composed of a plurality of water-jacket-type gravity heat pipes. The inner cavity of the shell 1 is provided with a partition 5 to divide the shell 1 into a cooling water heat exchange chamber 6 and a flue gas heat exchange chamber 7.

[0052] like Figure 3 As shown, the water-jacketed gravity heat pipe includes: a base pipe 8, a jacket 9, a jacket inlet water pipe 11, a jacket outlet water pipe 12, a jacket lower head 14 and a jacket upper head 15; the heat pipe base pipe 8 is filled with a working medium, the cooling water heat exchange part of the water-jacketed gravity heat pipe is arranged in the cooling water heat exchange cavity 6, and the flue gas heat exchange part is arranged in the flue gas heat exchange cavity 7. Two flow cavities 16 are formed between the base pipe 8 and the jacket 9 of the cooling water heat exchange part, and a connecting cavity 17 is provided at the bottom of the two flow cavities 16 for communication, as shown in FIG. Figure 2 As shown, the cooling water first flows downward through the jacket inlet water pipe 11 to the jacket lower head 14 area of ​​the water-jacket type gravity heat pipe, then turns upward to the jacket upper head 15 area, and flows out through the jacket outlet water pipe 12;

[0053] like Figure 1 As shown, the cross section of the base tube 8 of this embodiment is circular, and the cross section of the sleeve 9 is elliptical. The base tube 8 passes through the sleeve 9, and the outer wall of the base tube 8 is tangent to the inner wall of the sleeve 9 to form two flow cavities 16.

[0054] In this embodiment, the manufacturing process of the heat pipe can be: extruding the round sleeve 9 except the lower end portion into an elliptical shape, passing the sleeve 9 through the base tube 8 and connecting it to the sleeve lower head 14, rolling the sleeve 9 other than the end portion and sealing it with the base tube 8, and then further squeezing and compressing the elliptical sleeve 9 at the end portion to make it fit with the base tube 8.

[0055] In this embodiment, the cross-sections of the casing inlet water pipe 11 and the casing outlet water pipe 12 are elliptical.

[0056] In this embodiment, a gap of 0.7 mm is left between the top of the sleeve 9 and the base pipe 8, which enables the air retained in the sleeve before startup, the small amount of gas carried by the cooling water, and the steam generated by the overheating of the feed water to be smoothly discharged from the heat exchanger, thereby reducing the resistance of the water channel and ensuring the efficiency of heat exchange.

[0057] In this embodiment, the base tube 8 of the flue gas heat exchange part is provided with fins 13. By providing the fins 13, the heat exchange area can be increased. Figure 9 As shown, the fin 13 of this embodiment is a V-shaped toothed spiral fin structure.

[0058] In this embodiment, the heat pipe heat exchanger is composed of several heat pipe heat exchange modules, which are composed of several heat pipe groups. A single row of heat pipe groups is composed of several water-jacketed gravity heat pipes connected in series. The water-jacketed gravity heat pipes are connected in series through the jacket inlet water pipe 11 and the jacket outlet water pipe 12 to obtain a heat pipe group. The heat pipe groups are connected in parallel through the cooling water inlet header 3 and the cooling water outlet header 4 to obtain a heat pipe heat exchange module.

[0059] The working principle of the present invention is as follows: cooling water stored in the cooling water inlet header 3 enters the flow chamber 16 formed between the jacket 9 and the base tube 8 through the jacket inlet water pipe 11. The cooling water first flows downward through one flow chamber 16 to the connecting chamber 17 in the jacket lower head 14 area, then flows upward through the other flow chamber, and flows out through the jacket outlet water pipe 12 into the cooling water outlet header 4. During operation, the flue gas passes through the flue gas heat exchange chamber 7 of the shell 1. The base tube 8 of the flue gas heat exchange section of the water-jacket-type gravity heat pipe absorbs heat from the flue gas under the guidance of the fins 13, and transfers the heat to the working medium inside through the tube wall of the base tube 8. After absorbing heat, the working medium increases in temperature and evaporates into steam. The steam rises to the cooling water heat exchange section of the base tube 8, where it condenses and releases heat through the cooling water in the dual flow channels. The rising cooling water temperature removes the heat, and the working medium condenses and sinks back to the flue gas heat exchange section. This cycle repeats, effectively utilizing the waste heat of the flue gas.

[0060] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. An extruded split-flow shell-and-tube vacuum heat pipe heat exchanger, comprising a shell (1), a cooling water inlet header (3), a cooling water outlet header (4), and a heat pipe heat exchanger (2) communicating with the cooling water inlet header (3) and the cooling water outlet header (4), characterized in that: The heat pipe heat exchanger (2) disposed in the shell (1) is composed of a plurality of water-jacketed gravity heat pipes, and a partition (5) is provided in the inner cavity of the shell (1) to divide the shell (1) into a cooling water heat exchange chamber (6) and a flue gas heat exchange chamber (7) in the upper and lower parts; The water-jacket type gravity heat pipe comprises: a base pipe (8), a jacket (9), a jacket inlet water pipe (11), a jacket outlet water pipe (12), a jacket lower head (14) and a jacket upper head (15); the heat pipe base pipe (8) is filled with a working medium; the cooling water heat exchange portion of the water-jacket type gravity heat pipe is arranged in a cooling water heat exchange cavity (6); the flue gas heat exchange portion is arranged in a flue gas heat exchange cavity (7); two flow cavities (16) are formed between the base pipe (8) and the jacket (9) of the cooling water heat exchange portion; a connecting cavity (17) is provided at the bottom of the two flow cavities (16) for communication; the cooling water first flows downward through the jacket inlet water pipe (11) to the jacket lower head (14) area of ​​the water-jacket type gravity heat pipe, then turns upward to the jacket upper head (15) area, and flows out through the jacket outlet water pipe (12).

2. The extruded split-flow shell-and-tube vacuum heat pipe heat exchanger according to claim 1, characterized in that: The cross section of the base tube (8) is circular, the cross section of the sleeve (9) is elliptical, the base tube (8) passes through the sleeve (9), and the outer wall of the base tube (8) is tangent to the inner wall of the sleeve (9) to form two flow cavities (16).

3. The extruded split-flow shell-and-tube vacuum heat pipe heat exchanger according to claim 2, characterized in that: The cross sections of the casing inlet water pipe (11) and the casing outlet water pipe (12) are elliptical.

4. The extruded split-flow shell-and-tube vacuum heat pipe heat exchanger according to claim 1, characterized in that: A gap is left between the top of the sleeve (9) and the base pipe (8).

5. The extruded split-flow shell-and-tube vacuum heat pipe heat exchanger according to claim 4, characterized in that: The gap is 0.5-1 mm.

6. The extruded split-flow shell-and-tube vacuum heat pipe heat exchanger according to claim 1, characterized in that: Fins (13) are provided outside the base tube (8) of the flue gas heat exchange part.

7. The extruded split-flow shell-and-tube vacuum heat pipe exchanger according to claim 6, characterized in that: The fin (13) is a full-blade spiral fin structure, a U-shaped toothed spiral fin structure, or a V-shaped toothed spiral fin structure.

8. The extruded split-flow shell-and-tube vacuum heat pipe heat exchanger according to claim 1, characterized in that: When the extruded split-flow sleeve-type vacuum heat pipe heat exchanger is arranged in a vertical flue, it is arranged in an inclined manner with a bevel angle of 10-15°.

9. An extruded split-flow shell-and-tube vacuum heat pipe exchanger according to any one of claims 1 to 8, characterized in that: The heat pipe heat exchanger is composed of a plurality of heat pipe heat exchange modules, the heat pipe heat exchange module is composed of a plurality of heat exhaust pipe groups, and a single row of heat pipe groups is composed of a plurality of water-jacketed gravity heat pipes connected in series; the water-jacketed gravity heat pipes are connected in series via a jacket inlet water pipe (11) and a jacket outlet water pipe (12) to obtain a heat pipe group, and the heat pipe groups are connected in parallel via a cooling water inlet header (3) and a cooling water outlet header (4) to obtain a heat pipe heat exchange module.

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