Multistage efficient flue gas purification and waste heat recovery system

Abstract

This invention discloses a multi-stage high-efficiency flue gas purification and waste heat recovery system, relating to the field of waste heat recovery technology. It includes multiple heat exchange tubes, each with an external buffer mechanism to extend the contact between the flue gas and the tube, an external removal mechanism to reduce dust adhesion, an external impact mechanism to accelerate dust removal, and a bottom-mounted flipping mechanism to reduce dust re-adhesion. By incorporating the buffer mechanism and a perforated rotating disk driven by a first motor within the outer shell, the flue gas entering the shell cavity is periodically intercepted and released by the rotating disk, creating an intermittent buffering effect. This extends the residence time of the high-temperature flue gas in the heat exchange area, avoiding the bottleneck of insufficient heat exchange time in traditional straight-through flue systems. This allows heat to be more fully transferred to the heating medium within the heat exchange tubes, improving the overall waste heat recovery rate and reducing energy waste.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery technology, specifically a multi-stage high-efficiency flue gas purification and waste heat recovery system. Background Technology

[0002] In a boiler system, fuel is burned in the boiler to form flue gas, which is then discharged from the furnace. After passing through an air preheater, a dust collector, and an induced draft fan, the flue gas is discharged into the atmosphere through a chimney. Flue gas is a mixture of gases and dust, and it is the main cause of air pollution in residential areas. The composition of flue gas is very complex. The gases include water vapor, sulfur dioxide, nitrogen, oxygen, carbon monoxide, carbon dioxide, hydrocarbons, and nitrogen oxides, while the dust includes fuel ash, coal particles, oil droplets, and high-temperature pyrolysis products. Therefore, flue gas needs to be debleached and purified before being emitted.

[0003] To address the waste heat carried in flue gas, various devices for recovering waste heat from flue gas have emerged in the existing technology. The main method is to wrap a heating pipe containing a heating medium around the flue gas duct, transferring the heat from the flue gas to the heating medium in the heating pipe, thus raising the temperature of the heating medium and completing the heat exchange. However, the surface of the existing flue gas duct and the heat dissipation time in contact with it are limited. This results in the heat of the flue gas on the outermost layer of the flue gas duct being transferred relatively quickly, failing to fully convert the heat in the medium, wasting heat and reducing the conversion efficiency.

[0004] Therefore, this invention proposes a multi-stage high-efficiency flue gas purification and waste heat recovery system to compensate for and improve the shortcomings of existing technologies. Summary of the Invention

[0005] In view of the above problems, the invention provides a multi-stage high-efficiency flue gas purification and waste heat recovery system, which can effectively solve the problem of limited heat dissipation time on the surface of flue gas ducts and in contact with them in the prior art. To achieve the above objectives, embodiments of this application provide the following technical solutions: This invention discloses a multi-stage high-efficiency flue gas purification and waste heat recovery system, including multiple heat exchange tubes. The heat exchange tubes are provided with a buffer mechanism to extend the contact between the flue gas and the heat exchange tubes. The heat exchange tubes are also provided with a removal mechanism to reduce the adhesion of dust. The heat exchange tubes are provided with an impact mechanism to accelerate the removal of dust. The bottom of the heat exchange tubes is provided with a flipping mechanism to reduce the re-adhesion of dust on the outside of the heat exchange tubes. The buffer mechanism includes a shell fixedly connected to the outside of the heat exchange tube, and the two ends of the heat exchange tube extend to the two ends of the shell. Conical covers are symmetrically fixedly connected to the two ends of the shell. Smoke inlet and smoke outlet are respectively opened on both sides of the shell. The shell is rotatably connected to a rotating shaft.

[0006] Furthermore, one end of the rotating shaft extends into the housing, and a disc is coaxially fixedly connected to the extended end of the rotating shaft. The surface of the disc has multiple through holes for flue gas to pass through.

[0007] Furthermore, the multiple through holes are arranged in a ring, and the through holes match the smoke outlet. A first motor is also fixedly connected to the side of the outer casing, and the output end of the first motor is fixedly connected to the end of the rotating shaft away from the disk.

[0008] Furthermore, the removal mechanism includes a ring slidably fitted with a scraping ring for removing attached dust, and adjacent rings are fixedly connected to each other by a first connecting rod.

[0009] Furthermore, the removal mechanism also includes a slide rod horizontally fixedly connected inside the housing, and a second connecting rod slidably connected to the outside of the slide rod, with one end of the second connecting rod away from the slide rod fixedly connected to the side of the ring.

[0010] Furthermore, a screw is rotatably connected inside the housing, and the screw is threadedly connected to a protrusion on the side of one of the rings. A second motor is also fixedly connected outside the housing, and the output end of the second motor is fixedly connected to the extension end of the screw.

[0011] Furthermore, the impact mechanism includes mounting rods symmetrically slidably connected to the side of the first connecting rod, and a plurality of impact plates for impacting the heat exchange tube are fixedly connected between the two mounting rods, with the impact plates forming a 90-degree angle with the mounting rods.

[0012] Furthermore, the impact mechanism also includes a roller fixedly connected to one end of the mounting rod, a return spring is sleeved on the outside of the mounting rod, and the return spring is located between the roller and the first connecting rod. Protrusions are also fixedly connected at equal intervals on the inner side of the housing, and the roller is in rolling connection with the protrusions.

[0013] Furthermore, the flipping mechanism includes a collection chamber fixedly connected to the bottom of the outer shell, a cylindrical rotating body horizontally rotatably connected to the top of the collection chamber, symmetrically provided receiving slots for collecting dust inside the outer shell on the outer side of the rotating body, a guide rod vertically slidably connected inside the rotating body, and push plates symmetrically fixedly connected to both ends of the guide rod to push the dust out of the receiving slots, and the push plates are located inside the receiving slots.

[0014] Furthermore, inclined guide plates are symmetrically fixedly connected to the bottom of the outer shell, and the bottom of the guide plates extends to the top of the rotating body. A third motor is also fixedly connected to the outside of the collection chamber, and the output end of the third motor is fixedly connected to the rotating shaft of the rotating body.

[0015] The beneficial effects of this invention are as follows: 1. This device is equipped with a buffer mechanism. A rotating disk with through holes, driven by a first motor, is installed inside the outer shell. After the flue gas enters the outer shell cavity, it is periodically intercepted and released by the rotating disk, forming an intermittent buffering effect. This extends the residence time of high-temperature flue gas in the heat exchange area, avoids the bottleneck of insufficient heat exchange time in traditional straight-through flue, and allows heat to be transferred more fully to the heating medium in the heat exchange tube, thereby improving the overall waste heat recovery rate and reducing energy waste.

[0016] 2. This device is equipped with a removal mechanism. The second motor drives the screw to rotate, which in turn drives the threaded ring to slide smoothly along the axial direction of the heat exchange tube. Adjacent rings move synchronously through the first connecting rod to form a full-coverage scraping surface. This can continuously remove loose or initially accumulated dust during system operation, prevent the formation of a heat insulation layer, ensure the cleanliness of the heat exchange tube surface and thermal conductivity, extend the continuous operation cycle of the equipment, and reduce operation and maintenance costs.

[0017] 3. This device is equipped with an impact mechanism. When the removal mechanism moves, the roller compresses the return spring when it passes the protrusion. After passing the protrusion, the spring quickly rebounds, driving the impact plate to apply an instantaneous vertical impact force to the outer wall of the heat exchange tube. The mechanical knocking can shake off the hardened or firmly adhered dust particles, breaking the binding force between them and the tube wall. This overcomes the limitations of simple scraping and improves the system's adaptability under complex flue gas composition conditions.

[0018] 4. This device is equipped with a flipping mechanism. The dust scraped and impacted by the impact is guided by an inclined guide plate and falls into the receiving tank at the top of the rotating body. The third motor drives the rotating body to rotate at regular intervals. When the receiving tank rotates to the bottom position, the vertical sliding guide rod inside drives the push plate to move downward, pushing the accumulated dust in the tank to the sealed collection chamber below. This not only realizes the collection and automatic unloading of dust, but also breaks the vicious cycle of dust re-attachment. It solves the problem that the dust that is cleared and falls may be re-rolled up by the airflow after accumulating at the bottom of the equipment, causing secondary pollution or re-attaching to the heat exchange surface. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0020] Figure 1 This is a three-dimensional structural diagram from a first perspective in this invention.

[0021] Figure 2 This is a three-dimensional structural diagram from a second perspective in this invention.

[0022] Figure 3 This is a three-dimensional structural diagram of the caching mechanism in this invention.

[0023] Figure 4 This is a three-dimensional structural diagram of the removal mechanism in this invention.

[0024] Figure 5 This is a three-dimensional structural diagram of the impact mechanism in this invention.

[0025] Figure 6 This is a longitudinal cross-sectional view of the outer shell and the collection chamber in this invention.

[0026] Figure 7 This is a three-dimensional structural diagram of the heating mechanism in this invention.

[0027] The markings in the diagram represent: 10, heat exchange tube; 20, buffer mechanism; 201, outer shell; 202, outer cover; 203, flue gas inlet; 204, flue gas outlet; 205, disc; 206, rotating shaft; 207, through hole; 208, first motor; 30, removal mechanism; 301, ring; 302, slide bar; 303, first connecting rod; 304, screw; 305, second connecting rod; 306, second motor; 40, impact mechanism; 401, mounting rod; 402, impact plate; 403, roller; 404, return spring; 405, protrusion; 50, flipping mechanism; 501, collection chamber; 502, guide plate; 503, rotating body; 504, receiving groove; 505, push plate; 506, guide rod; 507, third motor. Detailed Implementation

[0028] 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. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] The present invention will be further described below with reference to embodiments.

[0030] See Figures 1 to 7 The multi-stage high-efficiency flue gas purification and waste heat recovery system of this embodiment includes multiple heat exchange tubes 10. A buffer mechanism 20 for extending the contact between the flue gas and the heat exchange tube 10 is provided on the outside of the heat exchange tube 10. A removal mechanism 30 for reducing the adhesion of dust is also provided on the outside of the heat exchange tube 10. An impact mechanism 40 for accelerating the removal of dust is provided on the outside of the heat exchange tube 10. A flipping mechanism 50 for reducing the re-adhesion of dust on the outside of the heat exchange tube 10 is provided at the bottom of the heat exchange tube 10.

[0031] See Figure 1 , Figure 2 and Figure 3 The buffer mechanism 20 includes a housing 201 fixedly connected to the outside of the heat exchange tube 10, and the two ends of the heat exchange tube 10 extend to the two ends of the housing 201. The two ends of the housing 201 are symmetrically fixedly connected with conical covers 202. The housing 201 has a smoke inlet 203 and a smoke outlet 204 on both sides respectively. The housing 201 is rotatably connected to a rotating shaft 206.

[0032] One end of the rotating shaft 206 extends into the housing 201, and a disc 205 is coaxially fixedly connected to the extended end of the rotating shaft 206. The surface of the disc 205 has multiple through holes 207 for flue gas to pass through.

[0033] Multiple through holes 207 are arranged in a ring, and the through holes 207 are matched with the smoke outlet 204. A first motor 208 is also fixedly connected to the side of the outer shell 201. The output end of the first motor 208 is fixedly connected to the end of the rotating shaft 206 away from the disk 205. High-temperature flue gas enters the outer shell 201 from the smoke inlet 203 and then exits from the smoke outlet 204. The heating medium enters the heat exchange tube 10 from one end of the outer cover 202 and exits from the other outer cover 202 after heat exchange.

[0034] In operation, after the high-temperature flue gas is discharged from the boiler, it enters the inlet 203 of this system through a pipe and flows into the heat exchange cavity formed by the outer shell 201, surrounding the heat exchange tube 10. The first motor 208 starts and drives the rotating shaft 206 to rotate, which in turn drives the disc 205, which is coaxially fixed at the end of the rotating shaft 206, to rotate synchronously. The surface of the disc 205 is provided with a plurality of through holes 207 arranged in a ring array. These through holes 207 periodically align with or stagger the outlet 204 as the disc 205 rotates. When the through holes 207 are aligned with the outlet 204, some flue gas passes through and is discharged. When they are staggered, the flue gas is temporarily trapped in the cavity, forming an intermittent buffering effect, which prolongs the contact time between the flue gas and the heat exchange tube 10, and prolongs the residence time of the high-temperature flue gas in the heat exchange area. This avoids the bottleneck of insufficient heat exchange time in traditional straight-through flue, allowing heat to be transferred more fully to the heating medium in the heat exchange tube 10, improving the overall waste heat recovery rate and reducing energy waste.

[0035] See Figure 1 , Figure 2 and Figure 4 The removal mechanism 30 includes a ring 301 slidably sleeved for scraping off attached dust, and adjacent rings 301 are fixedly connected to each other by a first connecting rod 303.

[0036] The removal mechanism 30 also includes a slide rod 302 that is horizontally fixedly connected inside the housing 201. A second connecting rod 305 is slidably connected to the outside of the slide rod 302. One end of the second connecting rod 305 away from the slide rod 302 is fixedly connected to the side of the ring 301.

[0037] Inside the outer casing 201, a screw 304 is rotatably connected. The screw 304 is threadedly connected to a protrusion on the side of one of the rings 301. Outside the outer casing 201, a second motor 306 is fixedly connected. The output end of the second motor 306 is fixedly connected to the extension end of the screw 304.

[0038] During actual operation, as the heat exchange process is buffered, dust gradually adheres to the outer wall of the heat exchange tube 10. To prevent the formation of an insulation layer, the second motor 306 is periodically started to drive the screw 304 to rotate. The screw 304 engages with the protrusion on the side of one of the rings 301, converting the rotational motion into the axial linear motion of the ring 301. All the rings 301 are rigidly connected by the first connecting rod 303 to achieve synchronous movement. At the same time, the second connecting rod 305 slides along the slide bar 302 to provide stable guidance for the rings 301, ensuring that they slide smoothly against the outer wall of the heat exchange tube 10. The inner edge of the ring 301 contacts the outer surface of the heat exchange tube 10. As the ring 301 moves, it scrapes off the loose dust adhering to it. During system operation, online, continuous, and full-coverage automatic dust removal is achieved, avoiding downtime maintenance and ensuring long-term stable heat exchange efficiency.

[0039] See Figure 1 , Figure 2 and Figure 5 The impact mechanism 40 includes mounting rods 401 symmetrically slidably connected to the side of the first connecting rod 303. A plurality of impact plates 402 for impacting the heat exchange tube 10 are fixedly connected between the two mounting rods 401, and the angle between the impact plates 402 and the mounting rods 401 is ninety degrees.

[0040] The impact mechanism 40 also includes a roller 403 fixedly connected to one end of the mounting rod 401. A return spring 404 is also sleeved on the outside of the mounting rod 401, and the return spring 404 is located between the roller 403 and the first connecting rod 303. Protrusions 405 are also fixedly connected at equal intervals on the inner side of the outer shell 201, and the roller 403 and the protrusions 405 are in rolling connection.

[0041] In specific operation, when the removal mechanism 30 is running, the first connecting rod 303 synchronously drives the mounting rods 401 on both sides to move. The rollers 403 at the end of the mounting rods 401 roll along the surface of the equidistant protrusions 405 preset on the inner wall of the outer shell 201. When the rollers 403 climb to the top of the protrusions 405, they compress the return springs 404 sleeved on the mounting rods 401. After passing the protrusions 405, the return springs 404 quickly rebound, pushing the mounting rods 401 to instantly reset. Multiple impact plates 402 perpendicular to the mounting rods 401 are fixed on them. Under the action of the rebound force of the return springs 404, the impact plates 402 violently strike the outer wall of the heat exchange tubes 10. The impact generates high-frequency, fixed-point mechanical impact, which effectively shakes off high-temperature sintered, firmly adhered, or plated dust, making up for the shortcomings of simple ash scraping. It is suitable for complex flue gas conditions such as high ash content, high humidity, or tar content.

[0042] See Figure 1 , Figure 2 , Figure 6 and Figure 7 The flipping mechanism 50 includes a collection chamber 501 fixedly connected to the bottom of the outer shell 201. A cylindrical rotating body 503 is horizontally rotatably connected to the top of the collection chamber 501. A receiving groove 504 for collecting smoke and dust inside the outer shell 201 is symmetrically opened on the outer side of the rotating body 503. A guide rod 506 is vertically slidably connected inside the rotating body 503. Push plates 505 that push out the smoke and dust in the receiving groove 504 are symmetrically fixedly connected to both ends of the guide rod 506. The push plates 505 are located inside the receiving groove 504.

[0043] An inclined guide plate 502 is symmetrically fixedly connected to the bottom of the outer shell 201. The bottom of the guide plate 502 extends to the top of the rotating body 503. A third motor 507 is also fixedly connected to the outside of the collection chamber 501. The output end of the third motor 507 is fixedly connected to the rotating shaft of the rotating body 503.

[0044] In actual operation, the dust scraped off by the removal mechanism 30 and shaken off by the impact mechanism 40 settles downward under the action of gravity. The inclined guide plate 502 guides the dust to the receiving groove 504 at the top of the rotating body 503, preventing the dust from scattering or being swept up by the airflow. The third motor 507 starts according to the set cycle, driving the rotating body 503 to rotate slowly around the horizontal axis. When the receiving groove 504 rotates to the bottom position with the rotating body 503, the internal guide rod 506 is pressed down by the gravity of another push plate 505 at the top and slides down in the vertical direction, driving the push plates 505 at both ends to move downward. The push plate 505 at the bottom completely pushes out the accumulated ash in the receiving groove 504 and it falls into the sealed collection chamber 501 below, realizing dust-free ash discharge, completely blocking the vicious cycle of re-attachment of the removed dust, ensuring the long-term cleanliness of the heat exchange area, and facilitating centralized treatment of waste ash to meet environmental emission requirements.

[0045] Working principle: High-temperature flue gas enters the outer casing 201 through the inlet 203. The first motor 208 drives the rotating shaft 206, which in turn rotates the disc 205. The through-hole 207 periodically aligns with the outlet 204, achieving flue gas interception and release, extending the residence time of the flue gas in the heat exchange zone, and improving heat exchange efficiency. Then, the second motor 306 in the removal mechanism 30 drives the screw 304 to rotate, causing the ring 301 to slide axially along the heat exchange tube 10. Multiple rings 301 move synchronously via the first connecting rod 303, scraping away loose dust adhering to the outer wall of the heat exchange tube 10. When 01 moves, the roller 403 on the mounting rod 401 in the impact mechanism 40 rolls along the protrusion 405 on the inner wall of the outer shell 201, compresses the return spring 404 and rebounds instantly, causing the impact plate 402 to strike the heat exchange tube 10, shaking off the slabs or stubborn dust. The fallen dust is guided by the guide plate 502 into the receiving groove 504 at the top of the rotating body 503. The third motor 507 drives the rotating body 503 to rotate at regular intervals. When the receiving groove 504 rotates to the bottom, the push plate 505 pushes the dust out to the collection chamber 501 under the action of the guide rod 506, realizing sealed automatic ash discharge.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-stage high-efficiency flue gas purification and waste heat recovery system, characterized in that, It includes multiple heat exchange tubes (10), and the heat exchange tubes (10) are provided with a buffer mechanism (20) for extending the contact between the flue gas and the heat exchange tubes (10), a removal mechanism (30) for reducing the adhesion of dust is also provided on the outside of the heat exchange tubes (10), an impact mechanism (40) for accelerating the removal of dust is provided on the outside of the heat exchange tubes (10), and a flipping mechanism (50) for reducing the re-adhesion of dust on the outside of the heat exchange tubes (10) is provided at the bottom of the heat exchange tubes (10). The buffer mechanism (20) includes a housing (201) fixedly connected to the outside of the heat exchange tube (10), and the two ends of the heat exchange tube (10) extend to the two ends of the housing (201). The two ends of the housing (201) are symmetrically fixedly connected with conical covers (202). The housing (201) has a smoke inlet (203) and a smoke outlet (204) on both sides respectively. The housing (201) is rotatably connected with a rotating shaft (206).

2. The multi-stage high-efficiency flue gas purification and waste heat recovery system according to claim 1, characterized in that, One end of the rotating shaft (206) extends into the housing (201), and a disc (205) is coaxially fixedly connected to the extended end of the rotating shaft (206). The surface of the disc (205) is provided with a plurality of through holes (207) for flue gas to pass through.

3. The multi-stage high-efficiency flue gas purification and waste heat recovery system according to claim 2, characterized in that, The multiple through holes (207) are arranged in a ring, and the through holes (207) are matched with the smoke outlet (204). A first motor (208) is also fixedly connected to the side of the outer shell (201). The output end of the first motor (208) is fixedly connected to the end of the rotating shaft (206) away from the disk (205).

4. The multi-stage high-efficiency flue gas purification and waste heat recovery system according to claim 1, characterized in that, The removal mechanism (30) includes a ring (301) slidably sleeved for scraping off attached dust, and adjacent rings (301) are fixedly connected to each other by a first connecting rod (303).

5. The multi-stage high-efficiency flue gas purification and waste heat recovery system according to claim 1, characterized in that, The removal mechanism (30) further includes a slide rod (302) that is horizontally fixed inside the housing (201). A second connecting rod (305) is slidably connected to the outside of the slide rod (302). One end of the second connecting rod (305) away from the slide rod (302) is fixedly connected to the side of the ring (301).

6. The multi-stage high-efficiency flue gas purification and waste heat recovery system according to claim 5, characterized in that, Inside the outer casing (201), a screw (304) is rotatably connected. The screw (304) is threadedly connected to the side protrusion of one of the rings (301). Outside the outer casing (201), a second motor (306) is fixedly connected. The output end of the second motor (306) is fixedly connected to the extension end of the screw (304).

7. The multi-stage high-efficiency flue gas purification and waste heat recovery system according to claim 1, characterized in that, The impact mechanism (40) includes mounting rods (401) symmetrically slidably connected to the side of the first connecting rod (303), and a plurality of impact plates (402) for impacting the heat exchange tube (10) are fixedly connected between the two mounting rods (401), and the angle between the impact plate (402) and the mounting rod (401) is ninety degrees.

8. The multi-stage high-efficiency flue gas purification and waste heat recovery system according to claim 7, characterized in that, The impact mechanism (40) also includes a roller (403) fixedly connected to one end of the mounting rod (401). A return spring (404) is also sleeved on the outside of the mounting rod (401), and the return spring (404) is located between the roller (403) and the first connecting rod (303). Protrusions (405) are also fixedly connected at equal intervals on the inner side of the outer shell (201), and the roller (403) and the protrusions (405) are in rolling connection.

9. The multi-stage high-efficiency flue gas purification and waste heat recovery system according to claim 1, characterized in that, The flipping mechanism (50) includes a collection chamber (501) fixedly connected to the bottom of the outer shell (201). A cylindrical rotating body (503) is horizontally rotatably connected to the top of the collection chamber (501). A receiving groove (504) for collecting smoke and dust inside the outer shell (201) is symmetrically opened on the outside of the rotating body (503). A guide rod (506) is vertically slidably connected inside the rotating body (503). Push plates (505) for pushing out smoke and dust in the receiving groove (504) are symmetrically fixedly connected at both ends of the guide rod (506). The push plates (505) are located inside the receiving groove (504).

10. The multi-stage high-efficiency flue gas purification and waste heat recovery system according to claim 9, characterized in that, The bottom of the outer shell (201) is symmetrically fixedly connected with inclined guide plates (502), the bottom of the guide plates (502) extends to the top of the rotating body (503), and a third motor (507) is also fixedly connected to the outside of the collection chamber (501), the output end of the third motor (507) is fixedly connected to the rotating shaft of the rotating body (503).

Images