A flue gas waste heat recovery device for a thermal power plant

Abstract

The present invention relates to the technical field of waste heat recovery equipment, and specifically discloses a waste heat recovery device for flue gas in a thermal power plant. It includes a box body with an upper smoke chamber, a heat exchange chamber and a lower smoke chamber inside. A number of smoke pipes connecting the upper smoke chamber and the lower smoke chamber are fixed in the heat exchange chamber; above the smoke pipes, there is a piston cylinder fixed by the box body; the upper end of the piston cylinder is connected to a high-pressure gas supply pipe, and a piston is arranged inside. The piston is connected with a scraping head through a push rod; side holes are provided on the push rod; when the high-pressure gas drives the piston to move downward, the scraping head moves along the inner wall of the smoke pipe to scrape off the ash slag. The waste heat recovery device for flue gas in this thermal power plant has a cleaning function and a better cleaning effect, high heat exchange efficiency and good waste heat recovery effect. The waste heat recovery device for flue gas in this thermal power plant can be automatically cleaned without disassembling components, is fast and efficient, and can be operated online. The ash slag scraped off during the cleaning process can be centrally recovered, avoiding re-mixing into the flue gas again, reducing the workload in the flue gas dust treatment link, and saving the subsequent environmental protection treatment cost.

Description

Technical Field

[0001] The present invention relates to the technical field of waste heat recovery equipment, and particularly to a waste heat recovery device for flue gas in a thermal power plant. Background Art

[0002] The flue gas generated during power generation in a thermal power plant contains a large amount of waste heat, and the waste heat in the flue gas needs to be recovered to improve the overall energy utilization rate and economic benefits. The tubular heat exchange device is the most commonly used waste heat recovery equipment for flue gas. During its operation, particulate matter (such as fly ash and unburned carbon) in the flue gas is likely to deposit on the tube wall when flowing through the heat exchange tubes due to reduced flow velocity, turbulent flow field or tube wall surface characteristics (such as roughness). If not cleaned in time, an adiabatic ash layer will form on the tube wall, significantly reducing the heat exchange efficiency between the flue gas and the medium and affecting the waste heat recovery effect. Currently, there are many technical improvements made for the above technical problems, such as:

[0003] An automatic ash cleaning device for a tubular heat exchanger and a tubular heat exchanger disclosed in the patent with the publication number CN222143905U integrates a purging component in the heat exchange cavity, which can purge the particulate matter attached to the surface of the heat exchange element to improve the heat exchange efficiency. This cleaning method can only remove loose ash deposits and is difficult to remove adhesive ash slag, resulting in poor cleaning effect. When the heat exchange efficiency significantly decays, the heat exchange elements still need to be removed for mechanical cleaning, which is troublesome to operate, has a high maintenance cost, and cannot be operated online, affecting the continuous production. In addition, during the operation of the purging component, the already settled particulate matter will be mixed into the flue gas again, increasing the workload of the subsequent flue gas dust treatment link and raising the environmental protection treatment cost.

[0004] A tube-cleanable tubular heat exchanger disclosed in the patent with the publication number CN222086803U sets mechanical cleaning components such as threaded rods, nuts, ash cleaning tube plates, and ash cleaning tubes in the shell, and at the same time sets cleaning components such as spray pipes and multiple groups of nozzles in the shell, which can achieve a better cleaning effect. However, this technical solution requires installing multiple groups of components in the shell, with a cumbersome and complex internal structure, and it is difficult to ensure the operation stability of the cleaning functional components in the long-term flue gas environment. In addition, although spraying can improve the cleaning effect, it also makes the tube wall more likely to adhere to the particulate matter in the flue gas and form dirt that is difficult to eradicate, thus requiring an increased cleaning frequency and increasing the operating energy consumption of the equipment. Summary of the Invention

[0005] To solve the deficiencies in the prior art, the present invention provides a waste heat recovery device for flue gas in a thermal power plant. This waste heat recovery device for flue gas in a thermal power plant can effectively remove the ash slag attached to the tube wall to ensure the heat exchange efficiency and improve the waste heat recovery effect. At the same time, the cleaning operation can be automatically completed online without stopping the machine and disassembling components, which is fast, efficient, and easy to maintain.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] A flue gas waste heat recovery device for a thermal power plant, comprising a box body. Inside the box body, there are an upper smoke chamber, a heat exchange chamber and a lower smoke chamber which are isolated from each other and distributed from top to bottom. The heat exchange chamber is connected with an input port and an output port, the upper smoke chamber is connected with a smoke outlet, and the lower smoke chamber is connected with a smoke inlet; A number of vertically arranged smoke pipes are fixed in the heat exchange chamber, and the upper smoke chamber and the lower smoke chamber are communicated through the smoke pipes; Above the positive side of each smoke pipe, there is a piston cylinder fixedly connected to the box body; The upper end of the piston cylinder is connected with a high-pressure gas supply pipe, the lower end is communicated with the upper smoke chamber, and a piston and an elastic member for driving the piston to reset to the initial position are arranged inside; The piston is fixedly connected with a push rod extending downward, and a scraping head is fixed at the lower end of the push rod; Side holes are opened on the side wall of the push rod, and axial holes are opened inside the piston and the push rod. The side holes are communicated with the internal space of the piston cylinder above the piston through the axial holes; When the piston is in the initial position, the scraping head is located above the smoke pipe; When the piston moves downward, the scraping head enters the corresponding smoke pipe and moves downward along the inner wall of the smoke pipe; A slag discharge outlet is arranged at the lower end of the lower smoke chamber, and a blocking mechanism is arranged on the slag discharge outlet.

[0008] In a preferred embodiment, the box body is composed of a top cover, a main shell and a bottom cover which are distributed up and down; The inside of the main shell is a heat exchange chamber, and partitions are fixed at its upper end and lower end. The two ends of the smoke pipe are respectively fixed and supported by the two partitions, and the input port and the output port are fixed on opposite sides of the main shell; The inside of the top cover is an upper smoke chamber, the smoke outlet is fixed on one side of the top cover, and the piston cylinder is fixed above the top cover; The inside of the bottom cover is a lower smoke chamber, and the smoke inlet is fixed on one side of the bottom cover; The upper smoke chamber and the lower smoke chamber are respectively isolated from the heat exchange chamber by the two partitions.

[0009] In a preferred embodiment, the piston cylinders are divided into several groups, and each group of piston cylinders is connected to the high-pressure gas supply pipe through a branch gas path, and a solenoid valve is installed on the branch gas path.

[0010] In a preferred embodiment, the elastic member is a tension spring, the upper end of which is fixedly connected to the piston cylinder, and the lower end extends downward in the central hole and is fixedly connected to the lower end of the push rod.

[0011] In a preferred embodiment, the lower smoke chamber is conical and tapers from top to bottom.

[0012] In a preferred embodiment, a sleeve is fixedly connected to the lower end of the push rod. When the piston is in the initial position, the scraping head is received in the corresponding sleeve and seals the lower end of the piston cylinder.

[0013] In a preferred embodiment, a discharge pipe extending downward is connected to the lower end of the lower flue chamber, and the ash discharge outlet is located at the lower end of the discharge pipe; a discharge wheel is rotatably connected inside the discharge pipe, and one or more material-carrying grooves are formed on the wheel surface of the discharge wheel. A driving mechanism for driving its rotation is connected to the discharge wheel; during the rolling process of the discharge wheel, the discharge pipe is always blocked, and the material-carrying groove can transfer the ash above the discharge wheel to the ash discharge outlet.

[0014] Further, the driving mechanism is an electric mechanism or a manual mechanism.

[0015] Still further, two wear-resistant liners are fixedly installed inside the discharge pipe, and the two wear-resistant liners are respectively located on opposite sides of the discharge wheel; the end faces of the wear-resistant liners opposite to the discharge wheel are arc-shaped, and the end faces are in sliding contact with the wheel surface of the discharge wheel.

[0016] In a preferred embodiment, the scraping head is cylindrical or disc-shaped, and metal bristles are evenly distributed on the upper middle part of the outer peripheral surface of the scraping head.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects:

[0018] [[ID=:15]]1. The flue gas waste heat recovery device of this thermal power plant can clean the inner wall of the flue pipe, and the cleaning effect is good, which can ensure that the flue pipe maintains stable heat conduction performance; its structural layout is scientific and reasonable, and the flue gas and the heat absorption medium have a large heat exchange area. Fins can be set outside the flue pipe without increasing the cleaning difficulty; thus, the heat exchange efficiency of the flue gas waste heat recovery device of this thermal power plant is high, and the waste heat recovery effect is good.

[0019] 2. The flue gas waste heat recovery device of this thermal power plant can automatically clean the flue pipe, without disassembling components, without manual operation, saving labor costs, fast and efficient; during the cleaning process, it will not have a substantial impact on the working conditions at the boiler end, enabling the cleaning work to be carried out online and ensuring the continuous and stable operation of the power generation system.

[0020] 3. When the flue gas waste heat recovery device of this thermal power plant cleans the flue pipe, the ash will settle to the bottom of the lower flue chamber for centralized recovery, maximizing the avoidance of the scraped ash from mixing into the flue gas again, significantly reducing the workload of the subsequent flue gas dust treatment link, and saving the subsequent environmental protection treatment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present invention and do not limit the present invention.

[0022] Figure 1 It is one of the overall structural schematic diagrams of the flue gas waste heat recovery device of the thermal power plant in the embodiment.

[0023] Figure 2 It is the second overall structural schematic diagram of the flue gas waste heat recovery device in the thermal power plant in the embodiment.

[0024] Figure 3 It is the structural decomposition schematic diagram of the flue gas waste heat recovery device in the thermal power plant in the embodiment.

[0025] Figure 4 It is the schematic diagram of the flow path of the heat absorption medium when the flue gas waste heat recovery device in the thermal power plant is working.

[0026] Figure 5 It is the schematic diagram of the flow path of the flue gas when the flue gas waste heat recovery device in the thermal power plant is working.

[0027] Figure 6 It is the structural schematic diagram of the upper smoke chamber and the components above it in the embodiment.

[0028] Figure 7 It is the schematic diagram of the matching structure of the piston cylinder, piston, push rod and tension spring in the embodiment.

[0029] Figure 8 It is the partial matching structural schematic diagram of the piston cylinder, piston, push rod and tension spring in the embodiment.

[0030] Figure 9 It is the schematic diagram of the clean state of the flue gas waste heat recovery device in the thermal power plant in the embodiment.

[0031] Figure 10 It is the schematic diagram of the matching structure of the lower smoke chamber, discharge pipe and discharge wheel in the embodiment.

[0032] Figure 11 It is the schematic diagram of the working state when the discharge wheel discharges ash slag by rotation in the embodiment.

[0033] Figure 12 It is the schematic diagram of the structure when metal bristles are arranged on the scraping wall head in the embodiment.

[0034] In the figure, 1. support, 2. bottom cover, 3. main housing, 4. top cover, 5. piston cylinder, 6. solenoid valve, 7. branch gas path, 8. high-pressure gas supply pipe, 9. output port, 10. ash slag discharge port, 11. smoke inlet, 12. smoke outlet, 13. input port, 14. smoke pipe, 15. partition plate, 16. lower smoke chamber, 17. heat exchange chamber, 18. upper smoke chamber, 19. scraping wall head, 20. sleeve, 21. tension spring, 22. axial hole, 23. piston, 24. push rod, 25. side hole, 26. horizontal rotating shaft, 27. hand wheel, 28. discharge wheel, 29. material carrying groove, 30. discharge pipe, 31. wear-resistant lining, 32. metal bristles. Specific implementation manners

[0035] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0036] Refer to Figures 1 - 5 As shown, the embodiment discloses a flue gas waste heat recovery device for a thermal power plant, which includes a box body supported and fixed by a bracket 1. Inside the box body, there are an upper smoke chamber 18, a heat exchange chamber 17 and a lower smoke chamber 16 distributed in sequence from top to bottom. The upper smoke chamber 18, the heat exchange chamber 17 and the lower smoke chamber 16 are isolated from each other. The heat exchange chamber 17 is connected with an input port 13 and an output port 9. The upper smoke chamber 18 is connected with a smoke outlet 12. The lower smoke chamber 16 is connected with a smoke inlet 11. A number of vertically arranged smoke pipes 14 are fixed in the heat exchange chamber 17. The upper smoke chamber 18 and the lower smoke chamber 16 are communicated through the smoke pipes 14. During the working process of this flue gas waste heat recovery device, high-temperature flue gas enters the lower smoke chamber 16 through the smoke inlet 11 and is dispersed into each smoke pipe 14. The flue gas flows upward in the smoke pipes 14 and finally converges in the upper smoke chamber 18 and is discharged through the smoke outlet 12. The heat absorption medium is selected from common substances such as water, air or heat-conducting oil. The heat absorption medium enters the heat exchange chamber 17 through the input port 13, absorbs the heat of the flue gas and is discharged through the output port 9, circulating, so as to recover the waste heat of the high-temperature flue gas.

[0037] Refer to Figure 1 、 Figures 6 - 9As shown in the figure, a piston cylinder 5 is provided directly above each smoke pipe 14; the piston cylinder 5 is cylindrical, extends vertically, and is fixedly connected to the box body at the lower end; the upper end of the piston cylinder 5 is connected to a high-pressure gas supply pipe 8, and the high-pressure gas supply pipe 8 is connected to a high-pressure gas source to input high-pressure gas into the interior of the piston cylinder 5. The lower end of the piston cylinder 5 communicates with the upper smoke chamber 18; a piston 23 and an elastic member are provided inside the piston cylinder 5; the piston 23 is in sealed sliding fit with the inner cavity of the piston cylinder 5 and can move up and down; the elastic member is connected between the piston 23 and the piston cylinder 5 and is used to drive the piston 23 to move upward to reset to the initial position; the piston 23 is fixedly connected with a push rod 24 extending downward, and a scraping head 19 capable of cooperating with the inner cavity of the smoke pipe 14 is fixed at the lower end of the push rod 24. Side holes 25 are provided on the side wall of the push rod 24; axial holes 22 are provided inside the piston 23 and the push rod 24, and the side holes 25 communicate with the internal space of the piston cylinder 5 above the piston 23 through the axial holes 22; when the piston 23 is in the initial position, the scraping head 19 is located above the smoke pipe 14. When the piston 23 moves downward, the scraping head 19 enters the corresponding smoke pipe 14 and moves downward along the inner wall of the smoke pipe 14 to scrape off the ash and slag adhering to the inner wall of the smoke pipe 14. During the normal operation of this flue gas waste heat recovery device, the piston 23 maintains the initial position. At this time, the scraping head 19 is located above the smoke pipe 14 and does not obstruct the flow path of the flue gas, so that the flue gas waste heat recovery device can work normally; when cleaning the inner wall of the smoke pipe 14, high-pressure gas is supplied into the piston cylinder 5 through the high-pressure gas supply pipe 8, and it is ensured that the supply speed of the high-pressure gas is greater than the discharge speed of the side holes 25. The high-pressure gas will push the piston 23 and the push rod 24 downward, and the scraping head 19 will enter the smoke pipe 14 below it and move downward along the inner wall of the smoke pipe 14, thereby scraping off the ash and slag adhering to the inner wall of the smoke pipe 14; at the same time, the high-pressure gas is sprayed at high speed through the side holes 25 of the push rod 24 onto the side wall of the smoke pipe 14 to further clean the residual ash and slag debris on the inner wall of the smoke pipe 14. The blown-off ash and slag debris enter the upper smoke chamber 18 with the airflow and are finally discharged through the smoke outlet 12; after the cleaning work is completed, the supply of high-pressure gas to the piston cylinder 5 is stopped, and the piston 23 is driven by the elastic member to move upward. The gas inside the piston cylinder 5 gradually leaks through the side holes 25, and finally the piston 23 resets to the initial position, and this flue gas waste heat recovery device resumes the normal working state.

[0038] See Figure 2 、 Figure 9 As shown in the figure, a slag discharge outlet 10 is provided at the lower end of the lower smoke chamber 16, and a blocking mechanism is provided on the slag discharge outlet 10; since the smoke pipe 14 extends vertically and the lower end communicates with the lower smoke chamber 16, after the ash and slag adhering to the inner wall of the smoke pipe 14 are scraped off, they will fall to the bottom of the lower smoke chamber 16, and the slag discharge outlet 10 can be used to regularly clean the accumulated ash and slag at the bottom of the lower smoke chamber 16.

[0039] The flue gas waste heat recovery device of this thermal power plant has a cleaning function. During the cleaning process, the scraping head 19 is used to mechanically scrape off the ash and slag, and high-pressure air flow is used to blow away the ash and slag debris, so as to obtain a good cleaning effect, ensure that the smoke pipe 14 maintains stable heat conduction performance, and improve the waste heat recovery efficiency. At the same time, the structural layout of the flue gas waste heat recovery device of this thermal power plant is relatively reasonable. The heat exchange chamber 17 is located between the upper smoke chamber 18 and the lower smoke chamber 16, and the smoke pipes 14 are arranged inside the heat exchange chamber 17, so that the flue gas and the heat absorption medium have a large heat exchange area, which can further improve the waste heat recovery performance. In addition, since the flue gas flows through the inside of the smoke pipe 14, the heat exchange efficiency can be improved by setting fins on the outside of the smoke pipe 14 without increasing the cleaning difficulty.

[0040] The cleaning operation of the flue gas waste heat recovery device of this thermal power plant can be automatically completed without disassembling parts, saving labor costs and being fast and efficient. During the cleaning process, the scraping head 19 can block the lumen of the smoke pipe 14, so that the high-pressure air flow ejected from the side holes 25 cannot flow downward in the smoke pipe 14, thereby avoiding the high pressure in the lower smoke chamber 16 from causing the flue gas to flow back; thanks to the automatic and efficient cleaning method, the cleaning process takes a short time, and the time for blocking the smoke pipe 14 during the cleaning process is very short; the lower smoke chamber 16 can play a certain buffering role and reduce the pressure fluctuation at the flue gas input end during the cleaning process; based on the above characteristics, the cleaning process will not have a substantial impact on the working conditions of the boiler end, enabling the cleaning work to be carried out online and ensuring the continuous and stable operation of the power generation system.

[0041] As Figure 9 shown, during the cleaning process, since the high-pressure air flow ejected from the side holes 25 cannot flow downward in the smoke pipe 14, the ash and slag scraped by the scraping head 19 will settle to the bottom of the lower smoke chamber 16 for centralized recovery, so as to avoid the scraped ash and slag from mixing into the flue gas again to the greatest extent, significantly reducing the workload of the subsequent flue gas dust treatment link and saving the subsequent environmental protection treatment cost.

[0042] For the convenience of assembly, the box body is preferably designed with a combined structure. Specifically, as Figures 1 - 5 shown, the box body is composed of a top cover 4, a main housing 3 and a bottom cover 2 which are sequentially distributed from top to bottom and are connected by bolts in combination; the inside of the main housing 3 is a heat exchange chamber 17, and partition plates 15 are fixed at its upper and lower ends. The two ends of the smoke pipe 14 are respectively fixed and supported by the two partition plates 15, and the input port 13 and the output port 9 are fixed on opposite sides of the main housing 3; the inside of the top cover 4 is an upper smoke chamber 18, and the smoke outlet 12 is fixed on one side of the top cover 4, and the piston cylinder 5 is fixed above the top cover 4; the inside of the bottom cover 2 is a lower smoke chamber 16, and the smoke inlet 11 is fixed on one side of the bottom cover 2; the upper smoke chamber 18 and the lower smoke chamber 16 are respectively isolated from the heat exchange chamber 17 by the two partition plates 15.

[0043] Preferably, as Figure 1 、Figure 2 , Figure 9 As shown in Figure 9 , the piston cylinder 5 is divided into several groups. Each group of piston cylinders 5 is connected to the high-pressure supply pipe 8 through a branch air circuit 7, and a solenoid valve 6 is installed on the branch air circuit 7. Thus, the working state of each group of piston cylinders 5 can be independently regulated. When cleaning the smoke pipe 14, high-pressure gas can be supplied to each group of piston cylinders 5 successively, so that the cleaning operation of the smoke pipe 14 is carried out batch by batch successively, and the flue gas can maintain a normal flow tendency in the flue gas waste heat recovery device of this thermal power plant, so as to reduce the impact on other equipment on the flue gas input side and output side during the cleaning process.

[0044] Preferably, as Figure 7 , Figure 8 shown, the elastic member is a tension spring 21, the upper end of which is fixedly connected to the piston cylinder 5, and the lower end extends downward in the central hole and is fixedly connected to the lower end of the push rod 24. Thus, the internal space of the piston cylinder 5 is fully utilized, the structural compactness is improved, and it is ensured that the elastic member has sufficient length to meet the working stroke requirements of the piston 23.

[0045] Preferably, as Figure 7 , Figure 8 shown, a sleeve 20 is fixedly connected to the lower end of the push rod 24. When the piston 23 is in the initial position, the wall scraping head 19 is accommodated in the corresponding sleeve 20 and seals the lower end of the piston cylinder 5. Based on this design feature, on the one hand, it can prevent the wall scraping head 19 from being exposed to the flue gas for a long time and adhering to ash, maintaining stable wall scraping performance. On the other hand, it can prevent the flue gas from entering the inside of the piston cylinder 5 and having an adverse impact on the matching effect between the piston 23 and the piston cylinder 5.

[0046] Preferably, as Figure 3 , Figure 9 shown, the lower smoke chamber 16 is conical, tapering from top to bottom, so as to facilitate the ash in the lower smoke chamber 16 to be discharged outwards through the ash discharge port 10.

[0047] In the flue gas waste heat recovery device of this thermal power plant, the blocking mechanism is arranged on the ash discharge port 10 to adjust the opening and closing state of the ash discharge port 10. During normal operation, the blocking mechanism closes the ash discharge port 10 to prevent flue gas leakage. When there is a large amount of ash accumulated in the lower smoke chamber 16, the blocking mechanism is adjusted to keep the ash discharge port 10 in an open state to discharge the ash in the lower smoke chamber 16. Based on the above setting intention of the blocking mechanism, the blocking mechanism has various implementation structures. For example, the blocking mechanism is a door device that can adjust the opening and closing state of the ash discharge port 10. A more preferred way is:

[0048] Refer to Figure 1 , Figure 2 , Figure 10 , Figure 11As shown, a discharge pipe 30 extending downward is connected to the lower end of the lower smoke chamber 16, and the ash discharge outlet 10 is located at the lower end of the discharge pipe 30; inside the discharge pipe 30, a discharge wheel 28 is rotatably connected via a horizontal rotating shaft 26, and one or more material-carrying grooves 29 are formed on the wheel surface of the discharge wheel 28. A driving mechanism for driving the discharge wheel 28 to rotate is connected to the discharge wheel 28; during the rolling process of the discharge wheel 28, the discharge pipe 30 is always blocked, that is, the discharge pipe 30 maintains a cut-off state to prevent the flue gas in the lower smoke chamber 16 from flowing to the outside through the discharge pipe 30; during the rolling process of the discharge wheel 28, the material-carrying groove 29 can transfer the ash on the upper side of the discharge wheel 28 to the ash discharge outlet 10; thus, by using the driving mechanism to drive the discharge wheel 28 to rotate, the ash cleaning operation can be performed. During this process, the flue gas will not be discharged to the outside through the discharge pipe 30, and the ash cleaning operation can be performed online, which is efficient and fast.

[0049] During implementation, the driving mechanism can be an electric mechanism such as a motor, so that the ash cleaning operation can be automatically completed; at the same time, the driving mechanism can also adopt a manual mechanism such as a handwheel 27 or a handle to perform the ash cleaning operation manually.

[0050] Furthermore, in order to improve the tightness of the cooperation between the discharge wheel 28 and the discharge pipe 30, two wear-resistant liners 31 are fixedly installed in the discharge pipe 30, and the two wear-resistant liners 31 are respectively located on opposite sides of the discharge wheel 28; the end surfaces of the wear-resistant liners 31 opposite to the discharge wheel 28 are arc surfaces, and the end surfaces are in sliding contact with the wheel surface of the discharge wheel 28.

[0051] Preferably, the scraping head 19 is cylindrical or disc-shaped to fit the lumen of the flue pipe 14 and reduce the cleaning dead angle. See Figure 12 As shown, to further improve the cleaning performance of the scraping head 19, metal bristles 32 are evenly distributed on the middle and upper parts of the outer peripheral surface of the scraping head 19; during the process of the scraping head 19 moving downward along the flue pipe, after scraping off the ash, the metal bristles 32 can clean the ash residue on the inner wall of the flue pipe.

[0052] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

[0053] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

Claims

1. A flue gas waste heat recovery device for a thermal power plant, comprising a housing, characterized in that: The interior of the box body is provided with an upper smoke chamber, a heat exchange chamber and a lower smoke chamber which are isolated from each other and distributed from top to bottom. The heat exchange chamber is connected to an input port and an output port, the upper smoke chamber is connected to a smoke outlet, and the lower smoke chamber is connected to a smoke inlet; a plurality of vertically arranged smoke pipes are fixed in the heat exchange chamber, and the upper smoke chamber and the lower smoke chamber are connected through the smoke pipes; a piston cylinder fixedly connected to the box body is provided just above each smoke pipe; the upper end of the piston cylinder is connected to a high-pressure air supply pipe, and the lower end is communicated with the upper smoke chamber, and a piston and an elastic member for driving the piston to return to the initial position are provided inside; the piston is fixedly connected to a push rod extending downward, and a wall scraping head is fixed to the lower end of the push rod; the side wall of the push rod is provided with a A side hole and an axial hole are provided inside the piston and the push rod, and the side hole is connected to the internal space of the piston cylinder on the upper side of the piston through the axial hole; when the piston is in the initial position, the scraper head is located above the smoke pipe; when the piston moves downward, the scraper head enters the corresponding smoke pipe and moves downward along the inner wall of the smoke pipe; an ash discharge outlet is provided at the lower end of the lower smoke chamber, and a sealing mechanism is provided on the ash discharge outlet; the scraper head is cylindrical or disc-shaped, and the upper and middle parts of the outer circumference of the scraper head are evenly covered with metal bristles; the lower end of the push rod is fixedly connected to a sleeve, and when the piston is in the initial position, the scraper head is received in the corresponding sleeve and seals the lower end of the piston cylinder.

2. The thermal power plant flue gas waste heat recovery device according to claim 1, characterized in that: The box body is composed of a top cover, a main shell and a bottom cover distributed above and below; the interior of the main shell is a heat exchange chamber, and partitions are fixed at the upper and lower ends of the main shell. The two ends of the smoke pipe are respectively fixedly supported by two partitions, and the input port and the output port are fixed on opposite sides of the main shell; the interior of the top cover is an upper smoke chamber, the smoke outlet is fixed on one side of the top cover, and the piston cylinder is fixed above the top cover; the interior of the bottom cover is a lower smoke chamber, and the smoke inlet is fixed on one side of the bottom cover; the upper smoke chamber and the lower smoke chamber are respectively isolated from the heat exchange chamber by two partitions.

3. The flue gas waste heat recovery device for a thermal power plant according to claim 1, characterized in that: The piston cylinders are divided into several groups, and each group of piston cylinders is connected to a high-pressure air supply pipe via a branch air path, and a solenoid valve is installed on the branch air path.

4. The thermal power plant flue gas waste heat recovery device according to claim 1, characterized in that: The elastic member is a tension spring, the upper end of which is fixedly connected to the piston cylinder, and the lower end of which extends downward in the center hole and is fixedly connected to the lower end of the push rod.

5. The thermal power plant flue gas waste heat recovery device according to claim 1, characterized in that: The lower smoke chamber is conical and gradually shrinks from top to bottom.

6. The flue gas waste heat recovery device for a thermal power plant according to claim 1, characterized in that: The lower end of the lower smoke chamber is connected to a discharge pipe extending downward, and the ash discharge outlet is located at the lower end of the discharge pipe; a discharge wheel is rotatably connected inside the discharge pipe, and one or more material carrying troughs are provided on the wheel surface of the discharge wheel, and the discharge wheel is connected to a driving mechanism for driving it to rotate; during the rolling process of the discharge wheel, the discharge pipe is always blocked, and the material carrying trough can transfer the ash on the upper side of the discharge wheel to the ash discharge outlet.

7. The thermal power plant flue gas waste heat recovery device according to claim 6, characterized in that: The driving mechanism is an electric mechanism or a manual mechanism.

8. The flue gas waste heat recovery device for a thermal power plant according to claim 6, characterized in that: Two wear-resistant linings are fixedly installed in the discharge pipe, and the two wear-resistant linings are respectively located on opposite sides of the discharge wheel; the end faces of the wear-resistant linings opposite to the discharge wheel are arc surfaces, and the end faces are in sliding contact with the wheel surface of the discharge wheel.

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