Flue gas waste heat recovery device and flue gas waste heat recovery method based on double-U-shaped shell-and-tube heat exchanger

Abstract

The invention relates to the technical field of flue gas waste heat recovery, and discloses a flue gas waste heat recovery device based on a double-U-shaped shell-and-tube heat exchanger and a flue gas waste heat recovery method. The lower surface of the supporting plate is fixedly connected with a fixed base; the cooling mechanism is mounted on the upper surface of the supporting plate and used for cooling the flue gas; the drainage mechanism is mounted at one end of the cooling mechanism and used for draining condensate water; the dust removal mechanism is mounted on one side of the drainage mechanism and is used for filtering the flue gas; and the dust removal mechanism comprises a filter box. High-temperature flue gas is conveyed into the filtering box through the flue gas conveying pipe, then the flue gas is filtered through the frame, so that dust falls into the bottom of the filtering box, falls into the dust discharging device and then falls into the dust storage box, and therefore the dust is collected, and the filtered flue gas enters the smoke discharging box; and the flue gas enters the second flue gas inlet pipe, so that the effect of filtering dust in the flue gas is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas waste heat recovery, and specifically to a flue gas waste heat recovery device and a flue gas waste heat recovery method based on a double U-tube shell-and-tube heat exchanger. Background Art

[0002] At present, the flue gas discharged during industrial production processes generally has a high temperature. Direct discharge not only causes waste of thermal energy but may also lead to environmental problems. Most traditional flue gas waste heat recovery methods rely on simple heat exchange pipes or straight-through heat exchangers, with low efficiency. The structural design often remains unchanged, resulting in a limited heat exchange area and poor heat exchange effect.

[0003] Most flue gas waste heat recovery devices have a simple structure, using conventional single-tube heat exchangers or traditional straight-tube heat exchange components. Although such structures have a low manufacturing cost, the heat exchange area is limited, and the residence time of flue gas in them is short, resulting in limited heat exchange efficiency. Especially under working conditions where the flue gas temperature fluctuates greatly or the flow rate is high, the problem of insufficient cooling is very obvious.

[0004] The cooling system generally performs poorly in dealing with condensate discharge. Many devices still use simple drain valves or open-hole liquid drainage methods, lacking a systematic condensate collection and drainage structure. The remaining condensate in the system not only easily causes water vapor backflow but may also trigger a series of safety hazards such as rust and blockage.

[0005] Flue gas dust removal generally uses a single-layer filter screen or a simple cyclone structure. This treatment method has low efficiency, and fine particles are easily discharged with the flue gas, polluting the secondary environment. The ash cleaning operation is inconvenient, the filter screen needs to be replaced frequently, and the manual burden is heavy. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present invention provides a flue gas waste heat recovery device and a flue gas waste heat recovery method based on a double U-tube shell-and-tube heat exchanger, which solve the problems of low heat exchange efficiency, untimely condensate treatment, and incomplete dust removal in the existing flue gas waste heat recovery system.

[0007] To achieve the above objectives, the present invention is realized through the following technical solutions: A flue gas waste heat recovery device and a flue gas waste heat recovery method based on a double U-tube shell-and-tube heat exchanger, including; A support plate, the lower surface of which is fixedly connected with a fixed base; A cooling mechanism, which is installed on the upper surface of the support plate and is used to cool the flue gas; A drainage mechanism, which is installed at one end of the cooling mechanism and is used to discharge condensate; A dust removal mechanism, which is installed on one side of the drainage mechanism and is used to filter the flue gas; The dust removal mechanism includes a filter box, the upper surface of the filter box is fixedly connected with a smoke exhaust box, a sealing plate is rotatably connected inside the smoke exhaust box, a second baffle is fixedly connected to the inner wall of the filter box, a frame is arranged inside the second baffle, a filter cloth bag is slidably connected inside the frame, and a smoke delivery pipe is fixedly connected inside the filter box; A condensation mechanism, which is installed on one side of the drainage mechanism and is used for condensing the flue gas.

[0008] Preferably, the cooling mechanism includes a cooling tank, a first partition is fixed inside the cooling tank, a first baffle is fixedly connected to the outer wall of the first partition, the outer wall of the first baffle is fixedly connected to the inner wall of the cooling tank, the outer walls of the first baffle are respectively fixedly connected to the outer walls of a first U-shaped pipe and a second U-shaped pipe, one end of the first U-shaped pipe is fixedly connected to the inner wall of the cooling tank, a second partition is fixedly connected to the inner wall of the cooling tank, the outer wall of the second partition is fixedly connected to the outer wall of the first baffle, a water inlet pipe and a first drain pipe are respectively fixedly connected to the outer wall of the cooling tank, and one end of the first drain pipe is fixedly connected to a hot water pipe.

[0009] Preferably, the drainage mechanism includes a sealing cover, the outer wall of the sealing cover is fixedly connected to the outer wall of the cooling tank, a third baffle is fixedly connected to the inner wall of the sealing cover, a fourth baffle is fixedly connected to the inner wall of the sealing cover, and a drain valve is fixedly connected inside the sealing cover.

[0010] Preferably, a second smoke inlet pipe is fixedly connected to the outer wall of the sealing cover, one end of the second smoke inlet pipe is fixedly connected to the outer wall of the smoke exhaust box, and a smoke outlet pipe is fixedly connected to the outer wall of the sealing cover.

[0011] Preferably, the condensation mechanism includes a condensation tank, a first smoke inlet pipe is fixedly connected to the outer wall of the condensation tank, one end of the first smoke inlet pipe is fixedly connected to one end of the smoke outlet pipe, a first delivery pipe is fixedly connected to the outer wall of the condensation tank, a smoke exhaust pipe is fixedly connected to the upper surface of the condensation tank, a third drain pipe is fixedly connected to the lower surface of the smoke exhaust pipe, a second drain pipe is fixedly connected to the inside of the condensation tank, one end of the second drain pipe is fixedly connected to the inside of the water inlet pipe, a fixing plate is fixedly connected to the inner wall of the condensation tank, a condensation pipe is fixedly connected to the inner wall of the fixing plate, a third partition is fixedly connected to the inner wall of the condensation tank, and the inner wall of the third partition is fixedly connected to the condensation pipe.

[0012] Preferably, a second support frame is fixedly connected to the outer wall of the condensation tank, and the lower surface of the second support frame is fixedly connected to the upper surface of the fixed base.

[0013] Preferably, one end of the third drain pipe is fixedly connected to a condensation box, the upper surface of the condensation box is fixedly connected to one end of a drain valve, and the lower surface of the condensation box is fixedly connected to the upper surface of a fixed base.

[0014] Preferably, a second connecting pipe is fixedly connected inside the condensation box. One end of the second connecting pipe is fixedly connected to a second water pump, the lower surface of the second water pump is fixedly connected to the upper surface of the fixed base, the output end of the second water pump is fixedly connected to a second delivery pipe, one end of the second delivery pipe is fixedly connected to a water tank, the outer wall of the water tank is fixedly connected to a first support frame, the lower surface of the first support frame is fixedly connected to the upper surface of the fixed base, the lower surface of the water tank is fixedly connected to a first connecting pipe, one end of the first connecting pipe is fixedly connected to a first water pump, the output end of the first water pump is fixedly connected to a cold water pipe, one end of the cold water pipe is fixedly connected to one end of a water inlet pipe, and the outer wall of the cold water pipe is fixedly connected to one end of the third drain pipe.

[0015] Preferably, the lower surface of the filter box is fixedly connected to a third support frame, the lower surface of the third support frame is fixedly connected to the upper surface of the fixed base, the lower surface of the filter box is fixedly connected to an ash discharger, the lower surface of the ash discharger is fixedly connected to an ash storage box, and the lower surface of the ash storage box is fixedly connected to the upper surface of the fixed base.

[0016] A method for recovering waste heat from flue gas of a waste heat recovery device based on a double U-tube shell-and-tube heat exchanger includes the following steps; The flue gas is conveyed into the filter box through a smoke delivery pipe, and the dust in the flue gas is filtered by a frame, so that the flue gas enters the inside of the sealing plate, and the dust falls into the ash discharger and is conveyed into the ash storage box; The filtered flue gas is conveyed into the inside of the sealing cover through a second smoke inlet pipe, and the flue gas is blocked by a third baffle, so that the flue gas enters the inside of the first U-tube and is conveyed from the other end between the third baffle and the fourth baffle and then conveyed into the inside of the second U-tube; The water in the water tank is pumped out by a first water pump and conveyed into the cold water pipe, and then conveyed into the water inlet pipe and enters the cooling tank. It is blocked by a first baffle and a first partition plate, so that the water flows on the outer walls of the first U-tube and the second U-tube. Then the water cools the flue gas inside, and then the flue gas is deeply cooled by the first U-tube and the second U-tube. Then the hot water is discharged into the hot water pipe through a first drain pipe and the hot water is discharged; After cooling, the flue gas is discharged into the interior of the first smoke inlet pipe through the smoke outlet pipe, and then transported into the interior of the condensation tank, causing the flue gas to enter the condensation pipe. Then, water flows into the first delivery pipe through the cold water pipe and is transported into the interior of the condensation tank. The third partition plate blocks the water flow, causing the water to flow on the outer wall of the condensation pipe, thereby cooling the condensation pipe and condensing the flue gas inside. The flue gas is discharged through the third drain pipe; The condensed water is discharged into the condensation box through the third drain pipe. The condensed water inside the sealing cover is discharged into the interior of the condensation box through the drain valve. The second water pump is started to pump the water out of the condensation box and transport it into the interior of the second delivery pipe, and then into the interior of the water tank, thereby storing the water.

[0017] The present invention provides a flue gas waste heat recovery device and a flue gas waste heat recovery method based on a double U-tube shell and tube heat exchanger. It has the following beneficial effects: 1. In the present invention, the high-temperature flue gas is transported into the interior of the filtration box through the smoke delivery pipe, and the flue gas is filtered through the frame, causing the dust to fall to the bottom of the filtration box and into the interior of the ash discharger, and then into the interior of the ash storage box, thereby collecting the dust. The filtered flue gas enters the interior of the smoke exhaust box and then into the interior of the second smoke inlet pipe, thereby achieving the effect of filtering the dust in the flue gas.

[0018] 2. In the present invention, cold water is transported into the interior of the cooling tank through the water inlet pipe. Through the second partition plate, the first partition plate and the first baffle, the water flows on the outer walls of the first U-tube and the second U-tube, thereby cooling and cooling the flue gas in the first U-tube and the second U-tube, and then increasing the contact time of the water to achieve the effect of enhancing the heat exchange efficiency and achieving the effect of deep cooling.

[0019] 3. In the present invention, the cooled flue gas is transported into the interior of the first smoke inlet pipe through the smoke outlet pipe, and then into the interior of the condensation tank and into the interior of the condensation pipe. Then, cold water enters the interior of the condensation tank through the first delivery pipe. The third partition plate causes the water flow to flow on the outer wall of the condensation pipe, thereby condensing the flue gas inside. The condensed water is discharged through the third drain pipe, thereby achieving the effect of removing the moisture in the flue gas. Brief Description of the Drawings

[0020] Figure 1 is a perspective view of the present invention; Figure 2 is a cross-sectional view of the filtration box of the present invention; Figure 3 is a schematic diagram of the support plate of the present invention; Figure 4 is a cross-sectional view of the cooling tank of the present invention; Figure 5 is a cross-sectional view of the sealing cover of the present invention; Figure 6 Schematic diagram of the condensation box of the present invention; Figure 7 Schematic diagram of the smoke exhaust pipe of the present invention; Figure 8 Cross-sectional view of the condensation tank of the present invention.

[0021] Wherein, 1, fixed base; 2, cooling mechanism; 201, cooling tank; 202, water inlet pipe; 203, first baffle; 204, first U-shaped pipe; 205, first partition; 206, second U-shaped pipe; 207, second partition; 208, first drain pipe; 3, dust removal mechanism; 301, smoke exhaust box; 302, second baffle; 303, filter box; 304, sealing plate; 305, frame; 306, filter cloth bag; 4, condensation mechanism; 401, condensation tank; 402, smoke exhaust pipe; 403, second drain pipe; 404, first smoke inlet pipe; 405, third drain pipe; 406, first conveying pipe; 407, third partition; 408, fixing plate; 409, condensation pipe; 5, water tank; 6, first support frame; 7, second support frame; 8, smoke delivery pipe; 9, third support frame; 10, ash discharger; 11, ash storage tank; 12, cold water pipe; 13, second smoke inlet pipe; 14, drainage mechanism; 1401, sealing cover; 1402, third baffle; 1403, fourth baffle; 1404, drain valve; 15, smoke outlet pipe; 16, condensation box; 17, hot water pipe; 18, support plate; 19, first connecting pipe; 20, first water pump; 21, second connecting pipe; 22, second water pump; 23, second conveying pipe. Detailed implementation manners

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] Please refer to the attached Figure 1 - attached Figure 8 , the embodiments of the present invention provide a flue gas waste heat recovery device and a flue gas waste heat recovery method based on a double U-tube shell and tube heat exchanger, including; Support plate 18, the lower surface of the support plate 18 is fixedly connected to the fixed base 1; Cooling mechanism 2, which is installed on the upper surface of the support plate 18 and is used to cool the flue gas; the cooling mechanism 2 includes a cooling tank 201, a first partition 205 is fixed inside the cooling tank 201, a first baffle 203 is fixedly connected to the outer wall of the first partition 205, the outer wall of the first baffle 203 is fixedly connected to the inner wall of the cooling tank 201, the outer walls of the first baffle 203 are respectively fixedly connected to the outer walls of a first U-shaped tube 204 and a second U-shaped tube 206, one end of the first U-shaped tube 204 is fixedly connected to the inner wall of the cooling tank 201, a second partition 207 is fixedly connected to the inner wall of the cooling tank 201, the outer wall of the second partition 207 is fixedly connected to the outer wall of the first baffle 203, a water inlet pipe 202 and a first drain pipe 208 are respectively fixedly connected to the outer wall of the cooling tank 201, and one end of the first drain pipe 208 is fixedly connected to a hot water pipe 17; Drainage mechanism 14, which is installed at one end of the cooling mechanism 2 and is used to drain condensed water; the drainage mechanism 14 includes a sealing cover 1401, the outer wall of the sealing cover 1401 is fixedly connected to the outer wall of the cooling tank 201, a third baffle 1402 is fixedly connected to the inner wall of the sealing cover 1401, a fourth baffle 1403 is fixedly connected to the inner wall of the sealing cover 1401, and a drain valve 1404 is fixedly connected to the inside of the sealing cover 1401; the outer wall of the sealing cover 1401 is fixedly connected to a second smoke inlet pipe 13, one end of the second smoke inlet pipe 13 is fixedly connected to the outer wall of the smoke exhaust box 301, and a smoke outlet pipe 15 is fixedly connected to the outer wall of the sealing cover 1401; Specifically, the flue gas enters the sealing cover 1401 through the second smoke inlet pipe 13, and then the flue gas is blocked by the third baffle 1402 so that it enters the first U-shaped tube 204, and then is discharged into the sealing cover 1401 from the other end. The third baffle 1402 and the fourth baffle 1403 block the flue gas so that the flue gas enters the second U-shaped tube 206, and then is discharged into the sealing cover 1401 from the other end, and the flue gas is blocked by the fourth baffle 1403 and discharged into the inside of the smoke outlet pipe 15, thereby discharging the flue gas. Cold water is transported into the cooling tank 201 through the water inlet pipe 202, and then the flow of water is rotated by the first baffle 203 and the first partition 205 so that the water flows on the outer wall of the first U-shaped tube 204, thereby cooling the flue gas in the first U-shaped tube 204 and the second U-shaped tube 206. After heat exchange, the hot water is discharged through the first drain pipe 208 and transported into the hot water pipe 17, thereby discharging the water. Furthermore, the flue gas is deeply cooled through the first U-shaped tube 204 and the second U-shaped tube 206. The second partition 207, the first partition 205 and the first baffle 203 enable the water to flow on the outer walls of the first U-shaped tube 204 and the second U-shaped tube 206, thereby improving the efficiency of heat exchange.

[0024] The dust removal mechanism 3 is installed on one side of the drainage mechanism 14 and is used for filtering the flue gas. The dust removal mechanism 3 includes a filter box 303. The upper surface of the filter box 303 is fixedly connected with a smoke exhaust box 301. A sealing plate 304 is rotatably connected inside the smoke exhaust box 301. A second baffle 302 is fixedly connected to the inner wall of the filter box 303. A frame 305 is arranged inside the second baffle 302. A filter cloth bag 306 is slidably connected inside the frame 305. A smoke delivery pipe 8 is fixedly connected inside the filter box 303. The lower surface of the filter box 303 is fixedly connected with a third support frame 9. The lower surface of the third support frame 9 is fixedly connected to the upper surface of the fixed base 1. A dust discharger 10 is fixedly connected to the lower surface of the filter box 303. The lower surface of the dust discharger 10 is fixedly connected with an ash storage box 11. The lower surface of the ash storage box 11 is fixedly connected to the upper surface of the fixed base 1 Specifically, the high-temperature flue gas is transported into the interior of the filter box 303 through the smoke delivery pipe 8, and the flue gas is filtered through the frame 305, so that the dust falls to the bottom of the filter box 303 and then into the interior of the dust discharger 10, and then the dust falls into the interior of the ash storage box 11, thereby collecting the dust. The filtered flue gas enters the interior of the smoke exhaust box 301, and then the flue gas enters the interior of the second smoke inlet pipe 13. By opening the sealing plate 304 and pulling out the filter cloth bag 306 from the frame 305, the frame 305 can be removed from the second baffle 302 for replacement.

[0025] The condensation mechanism 4 is installed on one side of the drainage mechanism 14 and is used for condensing the flue gas. The condensation mechanism 4 includes a condensation tank 401. The outer wall of the condensation tank 401 is fixedly connected with a first smoke inlet pipe 404. One end of the first smoke inlet pipe 404 is fixedly connected to one end of the smoke outlet pipe 15. The outer wall of the condensation tank 401 is fixedly connected with a first delivery pipe 406. The upper surface of the condensation tank 401 is fixedly connected with a smoke exhaust pipe 402. The lower surface of the smoke exhaust pipe 402 is fixedly connected with a third drain pipe 405. A second drain pipe 403 is fixedly connected inside the condensation tank 401. One end of the second drain pipe 403 is fixedly connected to the interior of the water inlet pipe 202. A fixing plate 408 is fixedly connected to the inner wall of the condensation tank 401. A condensation pipe 409 is fixedly connected to the inner wall of the fixing plate 408. A third partition 407 is fixedly connected to the inner wall of the condensation tank 401. The inner wall of the third partition 407 is fixedly connected to the condensation pipe 409. The outer wall of the condensation tank 401 is fixedly connected with a second support frame 7. The lower surface of the second support frame 7 is fixedly connected to the upper surface of the fixed base 1; Specifically, the cooled flue gas is transported through the smoke outlet pipe 15 into the interior of the first smoke inlet pipe 404, then into the interior of the condensation tank 401, and then into the interior of the condensation pipe 409. Then, cold water is introduced into the interior of the condensation tank 401 through the first delivery pipe 406. The water flow is made to flow on the outer wall of the condensation pipe 409 through the third partition 407, thereby condensing the flue gas inside. Then, the water is transported into the interior of the water inlet pipe 202 through the second drain pipe 403. The condensed water is discharged through the third drain pipe 405, and the condensed flue gas is discharged through the exhaust pipe 402. The condensation tank 401 can be supported by the second support frame 7.

[0026] One end of the third drain pipe 405 is fixedly connected to a condensation box 16. The upper surface of the condensation box 16 is fixedly connected to one end of a drain valve 1404, and the lower surface of the condensation box 16 is fixedly connected to the upper surface of a fixed base 1. A second connecting pipe 21 is fixedly connected inside the condensation box 16. One end of the second connecting pipe 21 is fixedly connected to a second water pump 22. The lower surface of the second water pump 22 is fixedly connected to the upper surface of the fixed base 1. The output end of the second water pump 22 is fixedly connected to a second delivery pipe 23. One end of the second delivery pipe 23 is fixedly connected to a water tank 5. The outer wall of the water tank 5 is fixedly connected to a first support frame 6. The lower surface of the first support frame 6 is fixedly connected to the upper surface of the fixed base 1. The lower surface of the water tank 5 is fixedly connected to a first connecting pipe 19. One end of the first connecting pipe 19 is fixedly connected to a first water pump 20. The output end of the first water pump 20 is fixedly connected to a cold water pipe 12. One end of the cold water pipe 12 is fixedly connected to one end of the water inlet pipe 202. The outer wall of the cold water pipe 12 is fixedly connected to one end of the third drain pipe 405. Specifically, the condensed water inside the sealing cover 1401 is discharged into the interior of the condensation box 16 through the drain valve 1404. Then, by starting the second water pump 22, the water in the condensation box 16 is pumped out through the second connecting pipe 21 and transported into the interior of the second delivery pipe 23, and thus transported into the interior of the water tank 5. Then, by starting the first water pump 20, the water in the water tank 5 is pumped out through the first connecting pipe 19, and then transported into the cold water pipe 12 and into the interior of the water inlet pipe 202. The water tank 5 is supported by the first support frame 6.

[0027] Working principle: First, high-temperature flue gas is transported to the inside of the filter box 303 through the flue gas delivery pipe 8. The flue gas is filtered by the frame 305, causing dust to fall to the bottom of the filter box 303 and then into the inside of the ash discharger 10, and further into the inside of the ash storage box 11, thereby collecting the dust. The filtered flue gas enters the inside of the smoke exhaust box 301 and then into the inside of the second flue gas inlet pipe 13. By opening the sealing plate 304 and pulling out the filter cloth bag 306 from the frame 305, the frame 305 is then removed from the second baffle 302 for replacement. The flue gas enters the sealing cover 1401 through the second flue gas inlet pipe 13 and is blocked by the third baffle 1402 to enter the first U-shaped pipe 204, and then discharged into the sealing cover 1401 from the other end. The third baffle 1402 and the fourth baffle 1403 block the flue gas to enter the second U-shaped pipe 206, and then discharged into the sealing cover 1401 from the other end. The fourth baffle 1403 blocks the flue gas and discharges it into the inside of the smoke outlet pipe 15, thereby discharging the flue gas. By starting the first water pump 20, the water in the water tank 5 is pumped out through the first connecting pipe 19, and then transported to the cold water pipe 12 and into the inside of the water inlet pipe 202. The cold water is transported to the inside of the cooling tank 201 through the water inlet pipe 202, and then the flow of water is rotated by the first baffle 203 and the first partition 205, causing the water to flow on the outer wall of the first U-shaped pipe 204, thereby cooling the flue gas in the first U-shaped pipe 204 and the second U-shaped pipe 206. After heat exchange, the hot water is discharged through the first drain pipe 208 and transported to the inside of the hot water pipe 17, thereby discharging the water. Furthermore, the first U-shaped pipe 204 and the second U-shaped pipe 206 achieve the effect of deeply cooling the flue gas. The second partition 207, the first partition 205, and the first baffle 203 cause the water to flow on the outer walls of the first U-shaped pipe 204 and the second U-shaped pipe 206, thereby improving the efficiency of heat exchange. The cooled flue gas is transported to the inside of the first flue gas inlet pipe 404 through the smoke outlet pipe 15 and then into the inside of the condensation tank 401 and into the inside of the condensation pipe 409. Then, cold water enters the inside of the condensation tank 401 through the first delivery pipe 406. The third partition 407 causes the water flow to flow on the outer wall of the condensation pipe 409, thereby condensing the internal flue gas. Then, the water is transported to the inside of the water inlet pipe 202 through the second drain pipe 403. The condensed water is discharged through the third drain pipe 405 and transported to the inside of the condensation box 16. The condensed flue gas is discharged through the third drain pipe 405. The condensed water inside the sealing cover 1401 is discharged into the condensation box 16 through the drain valve 1404. Then, by starting the second water pump 22, the water in the condensation box 16 is pumped out through the second connecting pipe 21 and transported to the inside of the second delivery pipe 23, and then transported to the inside of the water tank 5.

[0028] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A flue gas waste heat recovery device based on a double U-shaped shell and tube heat exchanger, characterized in that: include; A support plate (18), wherein the lower surface of the support plate (18) is fixedly connected to a fixed base (1); A cooling mechanism (2) mounted on the upper surface of the support plate (18) and used to cool the flue gas; A drainage mechanism (14), which is installed at one end of the cooling mechanism (2) and is used to drain condensed water; A dust removal mechanism (3) installed on one side of the drainage mechanism (14) and used for filtering the smoke; The dust removal mechanism (3) comprises a filter box (303), the upper surface of the filter box (303) is fixedly connected to a smoke exhaust box (301), the interior of the smoke exhaust box (301) is rotatably connected to a sealing plate (304), the inner wall of the filter box (303) is fixedly connected to a second baffle (302), a frame (305) is provided inside the second baffle (302), a filter bag (306) is slidably connected inside the frame (305), and the interior of the filter box (303) is fixedly connected to a smoke delivery pipe (8); The condensation mechanism (4) is installed on one side of the drainage mechanism (14) and is used to condense the flue gas.

2. The flue gas waste heat recovery device based on double U-shaped shell and tube heat exchanger according to claim 1 is characterized in that: The cooling mechanism (2) comprises a cooling tank (201), a first partition (205) being fixed inside the cooling tank (201), an outer wall of the first partition (205) being fixedly connected to a first baffle (203), an outer wall of the first baffle (203) being fixedly connected to an inner wall of the cooling tank (201), an outer wall of the first baffle (203) being fixedly connected to an outer wall of a first U-shaped tube (204) and an outer wall of a second U-shaped tube (206), one end of the first U-shaped tube (204) being fixedly connected to an inner wall of the cooling tank (201), a second partition (207) being fixedly connected to an outer wall of the second partition (207) being fixedly connected to an outer wall of the first baffle (203), an outer wall of the cooling tank (201) being fixedly connected to an inlet pipe (202) and a first drain pipe (208), and one end of the first drain pipe (208) being fixedly connected to a hot water pipe (17).

3. The flue gas waste heat recovery device based on double U-shaped shell and tube heat exchanger according to claim 1 is characterized in that: The drainage mechanism (14) comprises a sealing cover (1401), the outer wall of the sealing cover (1401) being fixedly connected to the outer wall of the cooling tank (201), the inner wall of the sealing cover (1401) being fixedly connected to a third baffle (1402), the inner wall of the sealing cover (1401) being fixedly connected to a fourth baffle (1403), and the interior of the sealing cover (1401) being fixedly connected to a drainage valve (1404).

4. The flue gas waste heat recovery device based on double U-shaped shell and tube heat exchanger according to claim 3 is characterized in that: The outer wall of the sealing cover (1401) is fixedly connected to a second smoke inlet pipe (13), one end of the second smoke inlet pipe (13) is fixedly connected to the outer wall of the smoke exhaust box (301), and the outer wall of the sealing cover (1401) is fixedly connected to a smoke outlet pipe (15).

5. The flue gas waste heat recovery device based on double U-shaped shell and tube heat exchanger according to claim 1 is characterized in that: The condensation mechanism (4) comprises a condensation tank (401), the outer wall of the condensation tank (401) being fixedly connected to a first smoke inlet pipe (404), one end of the first smoke inlet pipe (404) being fixedly connected to one end of a smoke outlet pipe (15), the outer wall of the condensation tank (401) being fixedly connected to a first delivery pipe (406), the upper surface of the condensation tank (401) being fixedly connected to a smoke exhaust pipe (402), the lower surface of the smoke exhaust pipe (402) being fixedly connected to a third drainage pipe (405), and the A second drain pipe (403) is fixedly connected to the interior of the condensation tank (401), one end of the second drain pipe (403) is fixedly connected to the interior of the water inlet pipe (202), a fixing plate (408) is fixedly connected to the inner wall of the condensation tank (401), a condensation pipe (409) is fixedly connected to the inner wall of the fixing plate (408), a third partition plate (407) is fixedly connected to the inner wall of the condensation tank (401), and the inner wall of the third partition plate (407) is fixedly connected to the condensation pipe (409).

6. The flue gas waste heat recovery device based on double U-shaped shell and tube heat exchanger according to claim 5 is characterized in that: The outer wall of the condensation tank (401) is fixedly connected to a second support frame (7), and the lower surface of the second support frame (7) is fixedly connected to the upper surface of the fixed base (1).

7. The flue gas waste heat recovery device based on double U-shaped shell and tube heat exchanger according to claim 5 is characterized in that: One end of the third drain pipe (405) is fixedly connected to a condensation box (16), the upper surface of the condensation box (16) is fixedly connected to one end of the drain valve (1404), and the lower surface of the condensation box (16) is fixedly connected to the upper surface of the fixed base (1).

8. The flue gas waste heat recovery device based on double U-shaped shell and tube heat exchanger according to claim 7 is characterized in that: A second connecting pipe (21) is fixedly connected inside the condensing tank (16), one end of the second connecting pipe (21) is fixedly connected to a second water pump (22), the lower surface of the second water pump (22) is fixedly connected to the upper surface of the fixed base (1), the output end of the second water pump (22) is fixedly connected to a second delivery pipe (23), one end of the second delivery pipe (23) is fixedly connected to a water tank (5), the outer wall of the water tank (5) is fixedly connected to a first support frame (6), the lower surface of the first support frame (6) is fixedly connected to the upper surface of the fixed base (1), the lower surface of the water tank (5) is fixedly connected to a first connecting pipe (19), one end of the first connecting pipe (19) is fixedly connected to a first water pump (20), the output end of the first water pump (20) is fixedly connected to a cold water pipe (12), one end of the cold water pipe (12) is fixedly connected to one end of a water inlet pipe (202), and the outer wall of the cold water pipe (12) is fixedly connected to one end of a third drain pipe (405).

9. The flue gas waste heat recovery device based on double U-shaped shell and tube heat exchanger according to claim 1 is characterized in that: The lower surface of the filter box (303) is fixedly connected to a third support frame (9), the lower surface of the third support frame (9) is fixedly connected to the upper surface of the fixed base (1), the lower surface of the filter box (303) is fixedly connected to an ash discharger (10), the lower surface of the ash discharger (10) is fixedly connected to an ash storage box (11), and the lower surface of the ash storage box (11) is fixedly connected to the upper surface of the fixed base (1).

10. A flue gas waste heat recovery method based on a flue gas waste heat recovery device with double U-shaped shell and tube heat exchangers, according to any one of claims 1 to 9, characterized in that: The steps include: The smoke is conveyed to the interior of the filter box (303) through the smoke conveying pipe (8), and dust in the smoke is filtered through the frame (305), so that the smoke enters the interior of the sealing plate (304), and the dust falls into the ash discharger (10) and is conveyed to the ash storage box (11); The filtered smoke is transported to the interior of the sealing cover (1401) through the second smoke inlet pipe (13), and the smoke is blocked by the third baffle (1402), so that the smoke enters the interior of the first U-shaped tube (204), and is transported from the other end to between the third baffle (1402) and the fourth baffle (1403), and then transported to the interior of the second U-shaped tube (206); The water in the water tank (5) is pumped out by the first water pump (20) and transported to the inside of the cold water pipe (12), and then transported to the water inlet pipe (202) to enter the inside of the cooling tank (201), and is blocked by the first baffle (203) and the first partition (205), so that the water flows on the outer walls of the first U-shaped tube (204) and the second U-shaped tube (206), thereby causing the water to cool the internal flue gas, and then deeply cool the flue gas through the first U-shaped tube (204) and the second U-shaped tube (206), and then the hot water is discharged into the hot water pipe (17) through the first drainage pipe (208), and the hot water is discharged; After being cooled, the smoke is discharged into the first smoke inlet pipe (404) through the smoke outlet pipe (15), and then transported to the inside of the condensation tank (401), so that the smoke enters the condensation pipe (409), and then water flows into the first transport pipe (406) through the cold water pipe (12) and is transported to the inside of the condensation tank (401), and the water flow is blocked by the third partition plate (407), so that the water flows on the outer wall of the condensation pipe (409), thereby cooling the condensation pipe (409), thereby condensing the smoke inside, and the smoke is discharged through the third drainage pipe (405); The condensed water is discharged into the condensation tank (16) through the third drain pipe (405), and the condensed water inside the sealing cover (1401) is discharged into the condensation tank (16) through the drain valve (1404). The water is pumped out of the condensation tank (16) by starting the second water pump (22) and transported to the inside of the second transport pipe (23), and then transported to the inside of the water tank (5), thereby storing the water.

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