Novel vacuum heat pipe heat exchanger with anti-abrasion smoke side and pressure-bearing water side

Abstract

The utility model relates to the technical field of flue gas waste heat utilization, and discloses a flue gas side anti-abrasion water side pressure-bearing novel vacuum heat pipe heat exchanger which comprises a top partition plate, a flue gas side heat exchange assembly is arranged at the lower end of the top partition plate, and a water side heat exchange assembly is arranged at the lower end of the top partition plate. The water side heat exchange pipe sleeve heat exchange branch line with the W-shaped plane and the S-shaped vertical face is adopted, the transverse pitch of the vacuum heat exchange pipe can be reduced, the overall size of the heat exchanger is reduced, the arrangement occupied space is reduced, it can be guaranteed that the sleeve directly bears the pressure of a condensation water system, condensation water and a vacuum heat pipe heat exchange medium directly conduct heat exchange, and the heat exchange efficiency is improved. The turbulent flow of cooling water is enhanced, countercurrent heat exchange between smoke and water is formed, and the heat exchange effect of the heat exchanger is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas waste heat utilization, in particular to a novel vacuum heat pipe heat exchanger with abrasion prevention on the flue gas side and pressure bearing on the water side. Background Technique

[0002] With the proposal of the national dual-carbon goal, thermal power units, which are major CO2 emitters, pay particular attention to energy conservation, emission reduction and upgrading. In order to further recover the heat loss caused by flue gas emissions, a large number of low-temperature economizers are installed at the tail of boilers. The traditional economizer uses a water-medium heat exchanger, and the heat exchanger structure type is a finned tube heat exchanger. In order to better cooperate with the electrostatic precipitator to improve the dust removal efficiency, the low-temperature economizer is generally arranged between the air preheater and the electrostatic precipitator. The flue gas at this position has a high dust concentration, and the flue gas with this dust concentration causes serious erosion and wear to the heat exchange tubes of the economizer. At the same time, the acidic gas in the flue gas has a corrosive effect on the heat exchange tubes. The heat exchanger is easily perforated after being in an environment of erosion, wear and corrosion for a long time. After perforation, the cooling water in the tube will leak to the flue gas side, causing the mixture of water and flue gas dust to deposit and harden at the bottom of the flue. At the same time, it will cause the entire serpentine heat exchange tube to lose its heat exchange capacity, and the cooling water in the tube of the entire heat exchange module needs to be stopped and isolated to avoid entering the flue, seriously affecting the operation reliability of the unit.

[0003] At present, the common solution is to use vacuum heat pipes with fins on the flue gas side, and the water side is a vacuum heat pipe with a very low pressure-bearing water tank. The vacuum heat pipe heat exchanger avoids the problem of continuous water entering the flue due to wear of the heat exchange tubes. However, due to the high-dust arrangement of the low-temperature economizer, the flue gas has a high dust concentration, and the flue gas severely erodes the finned vacuum heat pipes. The external fins of the vacuum heat pipes are severely worn under the erosion of high-dust flue gas for a long time, and the wear of the fins greatly reduces the heat exchange effect of the heat exchanger. The vacuum heat pipes with water tank heat exchange on the water side have a low pressure-bearing on the water side and cannot directly use boiler condensate for cooling. A new low-pressure water circulation system needs to be added to achieve indirect heat exchange between the flue gas heat exchanger and the boiler condensate system, increasing the complexity and failure points of the system.

[0004] Therefore, we propose a novel vacuum heat pipe heat exchanger with abrasion prevention on the flue gas side and pressure bearing on the water side to solve the above-mentioned problems. Content of the Utility Model

[0005] The purpose of the present utility model is to provide a new type of vacuum heat pipe heat exchanger with abrasion prevention on the flue gas side and pressure bearing on the water side, so as to solve the problems raised in the above background technology. Since the low-temperature economizer is arranged with high dust, the dust concentration in the flue gas is relatively high, and the flue gas severely erodes the finned vacuum heat pipes. The external fins of the vacuum heat pipes are severely worn under the erosion of high-dust flue gas for a long time, and the wear of the fins greatly reduces the heat exchange effect of the heat exchanger. The vacuum heat pipes with water tank type heat exchange on the water side have relatively low pressure bearing on the water side and cannot directly use boiler condensate for cooling. A new low-pressure water circulation system needs to be added to realize the indirect heat exchange between the flue gas heat exchanger and the boiler condensate system, increasing the complexity of the system and the problem of failure points.

[0006] To achieve the above purpose, the present utility model provides the following technical solutions: A new type of vacuum heat pipe heat exchanger with abrasion prevention on the flue gas side and pressure bearing on the water side, including a top partition. A flue gas side heat exchange component is arranged at the lower end of the top partition, and a water side heat exchange component is arranged at the lower end of the top partition. The flue gas side heat exchange component and the water side heat exchange component are separated by the top partition in the middle.

[0007] Preferably, the flue gas side heat exchange component includes a vacuum heat exchange tube and a false heat exchange tube arranged on one side of the vacuum heat exchange tube.

[0008] Preferably, the water side heat exchange component includes a cooling water inlet header and a cooling water inlet branch pipe arranged at the lower end of the cooling water inlet header.

[0009] Preferably, one end of the cooling water inlet branch pipe is provided with a water side heat exchange tube sleeve, and a water side sleeve connection pipe is arranged at the lower end of the water side heat exchange tube sleeve.

[0010] Preferably, on the other side at the upper end of the water side heat exchange component, there is a cooling water outlet header, and a cooling water outlet branch pipe is arranged at the lower end of the cooling water outlet header.

[0011] Preferably, a water side sleeve drain pipe is arranged at one end of the outer wall of the water side heat exchange component.

[0012] Compared with the prior art, the beneficial effects of the present utility model are:

[0013] 1. Adopting the heat exchange branch line form of the water side heat exchange tube sleeve in the shape of a planar W and a vertical S can not only reduce the transverse pitch of the vacuum heat exchange tube, reduce the overall volume of the heat exchanger, and reduce the occupied space for layout, but also ensure that the sleeve directly bears the pressure of the condensate system, enabling the condensate to directly exchange heat with the heat exchange medium of the vacuum heat pipe, strengthening the turbulent flow of the cooling water, forming a countercurrent heat exchange between the flue gas and the water, and greatly improving the heat exchange effect of the heat exchanger.

[0014] 2. The design of using false heat exchange tubes on the windward side of the heat exchanger can not only avoid the direct scouring of the vacuum heat exchange tubes on the windward side of the flue gas side, improve the wear resistance of the heat exchanger, but also equalize the flow of the flue gas entering the vacuum heat exchange tubes, optimize the inlet flue gas flow field, and improve the heat exchange conditions of the heat exchanger. Brief Description of the Drawings

[0015] Figure 1 is a schematic diagram of the overall structure of the present utility model;

[0016] Figure 2 is a front elevation schematic diagram of the water-side heat exchange assembly of the present utility model;

[0017] Figure 3 is a plan schematic diagram of the water-side heat exchange assembly of the present utility model;

[0018] Figure 4 is an example diagram of the layout of the vacuum heat pipe heat exchanger module of the present utility model.

[0019] In the figure: 1. Top partition; 2. Flue gas side heat exchange assembly; 21. Vacuum heat exchange tube; 22. False heat exchange tube; 3. Water side heat exchange assembly; 31. Cooling water inlet header; 32. Cooling water inlet branch pipe; 33. Water side heat exchange tube sleeve; 34. Water side sleeve connection pipe; 35. Cooling water outlet header; 36. Cooling water outlet branch pipe; 37. Water side sleeve drain pipe. Specific Embodiments

[0020] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0021] Embodiment 1: Please refer to Figures 1 - 2 , a new type of vacuum heat pipe heat exchanger with wear prevention on the flue gas side and pressure bearing on the water side, including a top partition 1. A flue gas side heat exchange assembly 2 is arranged at the lower end of the top partition 1, a water side heat exchange assembly 3 is arranged at the lower end of the top partition 1, and the middle parts of the flue gas side heat exchange assembly 2 and the water side heat exchange assembly 3 are separated by the top partition 1.

[0022] The vacuum heat pipe heat exchanger consists of a top partition 1, a flue gas side heat exchange component 2, and a water side heat exchange component 3. The heat exchange medium of the water side heat exchange component 3 exchanges heat with the heat exchange medium of the flue gas side heat exchange component 2. The heat exchange medium in the heat pipe is evaporated into a gaseous state after being heated by the flue gas on the lower flue gas side, and the gaseous medium rises to the upper water side of the heat pipe. After being cooled by the water on the upper water side, it condenses into a liquid state and flows down along the inner wall of the heat pipe to the lower flue gas side of the heat pipe. Then, it is heated and evaporated into a gaseous state by the flue gas again, forming a cycle, and continuously completing the heat exchange between the flue gas and water.

[0023] The water side heat exchange component 3 includes a cooling water inlet header 31 and a cooling water inlet branch pipe 32 provided at the lower end of the cooling water inlet header 31.

[0024] One end of the cooling water inlet branch pipe 32 is provided with a water side heat exchange tube sleeve 33, and a water side sleeve interconnection pipe 34 is provided at the lower end of the water side heat exchange tube sleeve 33.

[0025] On the other side of the upper end of the water side heat exchange component 3, a cooling water outlet header 35 is provided. A cooling water outlet branch pipe 36 is provided at the lower end of the cooling water outlet header 35, and a water side sleeve drain pipe 37 is provided at one end of the outer wall of the water side heat exchange component 3.

[0026] In this embodiment: The water side cooling water enters from the cooling water inlet header 31 arranged above the flue gas side outlet, and is evenly distributed to each cooling water inlet branch pipe 32 through the cooling water inlet header 31. The cooling water first enters from the upper part of the last row of water side heat exchange tube sleeves 33 in the flue gas flow direction, flows downwards in the heat exchange tube sleeve 33 to exchange heat with the heat exchange medium in the heat pipe, and then enters from the lower inlet of the penultimate row of water side heat exchange tube sleeves 33 in the flue gas flow direction through the lower water side sleeve interconnection pipe 34 at the lower part, flows upwards in the sleeve to exchange heat with the heat exchange medium in the heat pipe, and then enters from the upper water side sleeve interconnection pipe 34 of the third-to-last row of water side heat exchange tube sleeves 33, flows downwards in the sleeve to exchange heat with the heat exchange medium in the heat pipe, and then sequentially passes through each row of water side heat exchange tube sleeves 33 in the flue gas flow direction in order. Finally, it enters the cooling water outlet header 35 from the upper outlet of the first row of water side heat exchange tube sleeves 33 in the flue gas flow direction, completing the heat exchange process between the cooling water and the heat exchange medium in the vacuum heat pipe. The cooling water inlet branch pipe 32, the water side heat exchange tube sleeve 33, and the water side sleeve interconnection pipe 34 form a continuous W-shaped heat exchange branch line on the plane. Each heat exchange branch line is connected in parallel between the cooling water inlet header 31 and the cooling water outlet header 35 to form a heat exchange module. In order to facilitate the maintenance of water side drainage, the low points of the water side heat exchange tube sleeves at the ends of each W-shaped heat exchange branch line are connected to drainage pipes, which are aggregated to the water side sleeve drain pipe 37 for external drainage. This can not only facilitate the overflow of water during maintenance, but also avoid the freezing and expansion of water in the sleeve during the winter shutdown state, which may damage the heat exchange sleeve.

[0027] Embodiment 2: This embodiment is an improvement based on Embodiment 1. Specifically, please refer to Figures 3 - 4 , the flue gas side heat exchange component 2 includes vacuum heat exchange tubes 21 and dummy heat exchange tubes 22 arranged on one side of the vacuum heat exchange tubes 21. Anti-abrasion measures are provided on the windward side of the dummy heat exchange tubes 22. The water side uses vacuum heat exchange tubes 21 to directly bear the condensate water pressure.

[0028] The heat exchange tubes of the vacuum heat exchange tube 21 heat exchanger adopt a staggered arrangement as shown in Figure 3 , which can not only reduce the erosion of flue gas dust on the heat exchange tubes, extend the service life of the heat exchange tubes, and improve the reliability of the heat exchanger; but also strengthen the turbulent flow effect of the flue gas flowing through the heat exchange tubes, improve the mixing effect during the flue gas flow, optimize the velocity field and temperature field of the heat exchanger, and improve the heat exchange effect of the heat exchanger.

[0029] In this embodiment: The vacuum heat exchange tubes 21 in the flue gas side heat exchange component 2 are smooth tubes without fins added outside the tubes. At the same time, multiple rows of dummy heat exchange tubes 22 (there is no heat exchange medium in the tubes, made of high-wall-thickness anti-abrasion material, and anti-abrasion measures such as welded anti-abrasion angle steel or anti-abrasion arc plates are taken on the external windward side. The number of rows is determined according to the space size of the flue, generally 2 - 4 rows) are arranged in front of the windward side of the heat exchange tubes for the flue gas. The multiple rows of dummy heat exchange tubes 22 rectify the flue gas flow field entering the heat exchanger, optimize the heat exchange working conditions of the heat exchange tubes. At the same time, in order to strengthen the flue gas turbulence on the flue gas side and improve the convective heat exchange effect between the flue gas and the vacuum heat exchange tubes 21, the heat exchange tubes of the vacuum heat exchange tube 21 heat exchanger adopt a staggered arrangement (see Figure 3 ), so that the flue gas entering each row of heat exchange tubes can fully contact the heat exchange tubes, and when the flue gas passing through the front row of heat exchange tubes flows around the rear row of heat exchange tubes, it can be fully mixed and evenly distributed again, making the flue gas flow field and temperature field more uniform in each cross-section along the flue gas flow direction, and further improving the heat exchange effect between the flue gas and the medium in the heat exchange tubes.

[0030] In order to improve the operation flexibility, system reliability, and maintenance convenience of the vacuum heat pipe heat exchanger, the vacuum heat pipe heat exchanger adopts a modular design (see the example diagram in Figure 4), the module layout can be adjusted to M (the number of horizontal modules) × N (the number of vertical modules) according to the layout space. The heat exchange modules 1 arranged horizontally, the heat exchange modules 2 arranged, the heat exchange modules 3 arranged, and the heat exchange modules 4 arranged are in parallel. The heat exchange modules 5 arranged horizontally, the heat exchange modules 6 arranged, the heat exchange modules 7 arranged, and the heat exchange modules 8 arranged are in parallel. The heat exchange modules 9 arranged horizontally, the heat exchange modules 10 arranged, the heat exchange modules 11 arranged, and the heat exchange modules 12 arranged are in parallel. The heat exchange modules 1 arranged vertically, the heat exchange modules 5 arranged, and the heat exchange modules 9 arranged are in series. The heat exchange modules 2 arranged vertically, the heat exchange modules 6 arranged, and the heat exchange modules 10 arranged are in series. The heat exchange modules 3 arranged vertically, the heat exchange modules 7 arranged, and the heat exchange modules 11 arranged are in series. The heat exchange modules 4 arranged vertically, the heat exchange modules 8 arranged, and the heat exchange modules 12 arranged are in series. The flue gas flows through each heat exchange module in sequence from left to right. The cooling water is respectively introduced into the cooling water inlet headers 1 of the heat exchange modules 9, 10, 11, and 12 by the water supply main pipe. After heat exchange in the heat exchange modules, it flows through each series-connected module arranged along the flue gas flow direction in sequence, and finally enters the cooling water return main pipe through the cooling water outlet headers 9 of the heat exchange modules 1, 2, 3, and 4.

[0031] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0032] Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A new type of vacuum heat pipe heat exchanger with flue gas side wear protection and water side pressure bearing, comprising a top baffle (1), characterized in that: A flue gas side heat exchange component (2) is arranged at the lower end of the top baffle (1), a water side heat exchange component (3) is arranged at the lower end of the top baffle (1), and the middle parts of the flue gas side heat exchange component (2) and the water side heat exchange component (3) are separated by the top baffle (1).

2. According to claim 1, a new type of vacuum heat pipe heat exchanger with anti-wear on the flue gas side and pressure on the water side is characterized by: The flue gas side heat exchange component (2) comprises a vacuum heat exchange tube (21) and a dummy heat exchange tube (22) arranged on one side of the vacuum heat exchange tube (21).

3. According to claim 2, a new type of vacuum heat pipe heat exchanger with anti-wear on the flue gas side and pressure on the water side is characterized by: The water-side heat exchange component (3) comprises a cooling water inlet header (31) and a cooling water inlet branch pipe (32) arranged at the lower end of the cooling water inlet header (31).

4. According to claim 3, a new type of vacuum heat pipe heat exchanger with anti-wear on the flue gas side and pressure on the water side is characterized by: A water-side heat exchange tube sleeve (33) is provided at one end of the cooling water inlet branch pipe (32), and a water-side sleeve-to-sleeve connecting pipe (34) is provided at the lower end of the water-side heat exchange tube sleeve (33).

5. According to claim 4, a new type of vacuum heat pipe heat exchanger with anti-wear on the flue gas side and pressure on the water side is characterized by: A cooling water outlet header (35) is provided on the other side of the upper end of the water-side heat exchange component (3), and a cooling water outlet branch pipe (36) is provided at the lower end of the cooling water outlet header (35).

6. The novel vacuum heat pipe heat exchanger with flue gas side wear protection and water side pressure bearing according to claim 5 is characterized in that: A water-side casing drain pipe (37) is provided at one end of the outer wall of the water-side heat exchange component (3).

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