Automatic recovery system for waste heat of boiler flue gas

Abstract

The invention discloses a boiler flue gas waste heat automatic recovery system, and belongs to the technical field of boiler flue gas waste heat recovery, the boiler flue gas waste heat automatic recovery system comprises a box body with a hollow structure inside, the side, facing a gas inlet pipe, of the inner wall of the box body is arranged to be an arc-shaped surface, and a flue gas flow speed control assembly is installed inside the gas inlet pipe; the starting point and the flow field distribution are used for changing flue gas flow velocity; an adjustable swing heat exchange assembly is installed in the box body and used for generating strong relative movement and convection between high-temperature flue gas and the pipe wall, and the convection heat exchange coefficient is increased. By the adoption of the adjustable swing heat exchange assembly and the flue gas flow speed control assembly, the flow speed can be increased and heat convection can be enhanced at the initial section where boiler flue gas enters the box body, a stable thermal boundary layer of the flue gas and water flow is destroyed through axial reciprocating swing of the heat exchange pipes, meanwhile, the water flow in the pipes is changed into pulsating flow and turbulent flow, and the heat exchange efficiency is improved. And the overall heat exchange coefficient is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of boiler flue gas waste heat recovery technology, specifically relating to an automatic boiler flue gas waste heat recovery system. Background Technology

[0002] When a boiler is running, fuel (such as coal, natural gas, oil, etc.) reacts with oxygen to generate heat, which promotes the formation of steam. During combustion, unburned fuel and other products are discharged in the form of flue gas, carrying a large amount of heat. Boiler flue gas mainly consists of steam, carbon dioxide, carbon monoxide, nitrogen, oxygen, and some unburned hydrocarbons and other pollutants. Among them, steam and carbon dioxide are the main components of flue gas, carrying a large amount of latent heat and sensible heat. If they are not recovered, this heat will be wasted. The utilization of waste heat from flue gas can convert this waste heat into usable energy, significantly reducing resource waste. Traditionally, when recovering and utilizing boiler flue gas, heat exchangers are often used to heat water with flue gas, and then the heated water is transported to an energy storage tank for recovery and reuse through insulated pipes.

[0003] When flue gas enters the heat exchanger, it passes through the fixed heat exchange tube structure inside the heat exchanger. The heat exchange tube absorbs the residual heat in the flue gas. Whether on the flue gas side or the water side, the fluid forms a stable thermal boundary layer on the surface of the stationary tube wall. This is the main resistance to heat transfer, thereby reducing the overall heat exchange efficiency. This boundary layer usually thickens as the flow velocity decreases, further increasing the resistance to heat transfer. As the operating time increases, the accumulation of deposits on the surface of the heat exchange tube will cause the heat exchange efficiency to gradually decrease. Regular cleaning or maintenance is required to restore system performance. This periodic decline not only affects the operating efficiency of the boiler, but may also lead to an increase in energy consumption. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an automatic waste heat recovery system for boiler flue gas.

[0005] The technical solution adopted to solve the above technical problems is: an automatic waste heat recovery system for boiler flue gas, including a box with a hollow internal structure, with an air inlet pipe and an exhaust pipe installed on both sides of the box, a control panel installed on one side of the outer wall of the box, an installation frame installed at the bottom of the box, the inner wall of the box facing the air inlet pipe being arc-shaped, and the inner wall of the box facing the exhaust pipe being conical, and a water inlet pipe and a drain pipe being fixedly connected through the top and bottom of the box, respectively; The air inlet pipe is equipped with a flue gas velocity control component, which is used to change the starting point and flow field distribution of the flue gas velocity. The chamber is equipped with an adjustable swing heat exchange component, which is used to generate strong relative motion and convection between the high-temperature flue gas and the pipe wall, thereby improving the convective heat transfer coefficient.

[0006] Through the above technical solution, the flue gas velocity is increased when it passes through the flue gas velocity control component, thereby "pre-treating" the flue gas. The fluid shear force is used to remove some loose ash particles and prevent large particles from settling. Subsequently, the adjustable swing heat exchange component performs "deep cleaning" on the heat exchange tubes. The mechanical swing removes the tightly attached ash, achieving a comprehensive and three-dimensional enhancement of the heat exchange process. This ensures that the heat exchange gain brought by the high-speed flue gas is not offset by the ash accumulation on the tube wall and the stable boundary layer, but is further amplified by the swing component, thereby maximizing the overall heat transfer efficiency of the system.

[0007] Furthermore, the flue gas flow rate control component includes a slot that extends through the top of the air inlet pipe, and a deflector plate is provided in the slot. The deflector plate is rotatably connected to the air inlet pipe, and the air inlet pipe limits the deflector plate. At the same time, the deflector plate's actuating part is located outside the air inlet pipe. The inner wall of the deflector plate has several teeth that are symmetrically distributed in a circle, and gears that are rotatably connected to the air inlet pipe are provided at the teeth of the deflector plate. The gears mesh with the deflector plate.

[0008] With the above technical solution, the flow rate can be quickly adjusted by manually moving the lever, and can be flexibly adjusted according to the fluctuations in boiler flue gas flow and temperature (such as start-up, shutdown, and fuel switching), adapting to different operating scenarios without the need for complex control logic.

[0009] Furthermore, a wedge plate is provided between several gears, and a sliding groove is provided through the wedge plate. At the same time, two limiting rods fixedly connected to the air inlet pipe are provided inside the sliding groove. The limiting rods are slidably connected to the sliding groove and limit the sliding groove, so that the sliding groove slides along the axial direction of the limiting rods. Several transmission teeth that mesh with the gears are provided on the side of the wedge plate facing the gears, and the wedge plate achieves synchronous linkage with the gears through the transmission teeth. At the same time, several wedge plates are slidably connected to each other.

[0010] Through the above technical solution, the synchronous movement of the wedge plate can adjust the flow field at the flue gas inlet, allowing the high-temperature flue gas to cover the surface of the heat exchange tube more evenly, avoiding heat exchange dead zones caused by local flue gas short circuits or uneven flow rates, and improving the utilization rate of the heat exchange surface.

[0011] Furthermore, the adjustable swing heat exchange assembly includes a heat exchange tube located at the center of the air inlet pipe and the exhaust pipe, and a second metal tube and a first metal tube are fixedly connected to the top and bottom of the heat exchange tube, respectively. The second metal tube and the first metal tube are corrugated pipe structures made of flexible metal material. The other ends of the first metal tube and the second metal tube are respectively installed and fixed to the drain pipe and the water inlet pipe at the bottom and top of the box. A connecting plate is installed and fixed on the inner wall of the heat exchange tube, and a slot is opened through the middle of the connecting plate. At the same time, a fixing frame fixedly connected to the box is set inside the slot.

[0012] Through the above technical solution, the heat exchange tube actively swings to disrupt the stable insulating gas boundary layer on the surface of the stationary tube wall, causing strong relative motion between the high-temperature flue gas and the tube wall, reducing heat transfer resistance. The swinging motion causes the water flow inside the tube to change from laminar flow to pulsating flow and turbulent flow, disrupting the water's thermal boundary layer and improving the heat transfer efficiency from the tube wall to the water. This solves the problem of weak heat transfer at the rear end caused by the thickening of the boundary layer in traditional "fixed heat exchange tubes".

[0013] Furthermore, the top of the fixed frame is rotatably connected to several cams, and the cams are arranged in pairs. At the same time, the two cams in a pair are arranged in a mirror symmetrical manner. The middle of the cam is rotatably connected to the box body, and a connecting rod is rotatably connected between the bottom ends of the two cams in a pair. At the same time, two connecting parts are rotatably connected between the other ends of the connecting rods located on both sides of the box body. A fixed rod is rotatably connected between the two connecting parts, and a sliding rod is slidably connected through the middle of the connecting parts. The sliding rod is fixedly connected to the box body. The connecting plate is rotatably connected through the connecting rod and the connecting parts.

[0014] Furthermore, two worm gears are rotatably connected to one side of the top of the fixed frame, and the worm gear connecting shaft is rotatably connected to the fixed frame through it. At the same time, the through end of the worm gear connecting shaft is fixedly connected to the cam. The top of the two worm gears are respectively connected to a first worm and a second worm, and the first worm and the second worm are slidably connected through it. At the same time, the first worm axially limits the second worm. One end of the first worm is rotatably connected to the fixed frame, and the other end of the first worm is rotatably connected to the fixed frame through it.

[0015] Through the above technical solution, the oscillation of the heat exchange tube can promote heat exchange between the flue gas and the tube wall, making the wall temperature of each part of the tube bundle more uniform and avoiding local cold spots. At the same time, the oscillation can prevent or slow down the deposition of scale.

[0016] Furthermore, a movable component is fixedly connected to one end of the second worm gear, and the first worm gear is slidably connected to the movable component. At the same time, a sleeve plate is rotatably connected inside the movable component, and a threaded rod is threadedly connected to the other end of the sleeve plate. One end of the threaded rod is rotatably connected to the fixed frame, and the other end of the threaded rod is rotatably connected to the fixed frame.

[0017] Furthermore, a No. 1 motor and a No. 2 motor are respectively installed on both sides of the housing, with the No. 1 motor and the control panel located on the same side. The output ends of the No. 1 motor and the No. 2 motor are equipped with drive shafts, and the drive shafts at the output ends of the No. 1 motor and the No. 2 motor are rotatably connected through the housing. The through end of the drive shaft at the output end of the No. 1 motor is fixedly connected to a threaded rod, and the through end of the drive shaft at the output end of the No. 2 motor is fixedly connected to a No. 1 worm gear.

[0018] Through the above technical solutions, the inertial force of the swing will "throw" the accumulated dust that has adhered but is not firmly bonded away from the tube wall, keeping the heat exchange surface clean for a long time, maintaining the designed heat exchange efficiency, and reducing maintenance costs.

[0019] The beneficial effects of this invention are as follows: This invention employs an adjustable oscillating heat exchange component. The second motor directly drives the first worm gear to rotate, and the first worm gear limits the second worm gear, causing them to rotate synchronously. This, in turn, causes both worm wheels to rotate simultaneously, prompting the two sets of cams to rotate synchronously. This, in turn, drives the two connecting rods to reciprocate up and down. Simultaneously, the ends of the connecting rods rotate relative to the cams and connecting parts, respectively. This, in turn, causes the connecting plate, which is fixed to the heat exchange tube, to slide back and forth along the slide rod axis via the connecting parts. This oscillation violently disturbs the flow of water on the flue gas side and inside the tube, transforming laminar flow into turbulent flow. It also disrupts the thermal boundary layer between the flue gas and water, thereby significantly increasing the convective heat transfer coefficient on both sides of the tube wall and improving heat transfer efficiency. This invention directly drives the threaded rod to rotate via a primary motor, causing the slider on the threaded rod to move along the linear direction of the threaded rod. This, in turn, causes the moving part on one side of the slider to move along the linear direction of the primary worm, with the secondary worm following suit. This changes the meshing position of the secondary worm and the worm wheel, thereby causing the cam connected to the worm wheel to rotate by a certain angle. This changes the reciprocating stroke of the two connecting rods, thus adjusting the heat exchange tube to move up and down while simultaneously oscillating axially. This allows for changes in the oscillation stroke (amplitude) of the heat exchange tube. It can increase the oscillation amplitude to enhance heat exchange when the flue gas temperature is high and the load is heavy, and can also be adjusted appropriately at low loads to avoid energy waste, making it highly adaptable. This invention employs a flue gas velocity control component. By manually moving a lever, the gears and wedges move, altering the cross-sectional area of ​​the inlet pipe. With a constant flue gas flow rate, reducing the cross-sectional area increases the flue gas velocity. The higher velocity enhances convective heat transfer and carries more and larger ash particles into the chamber, preventing blockage at the inlet. Simultaneously, it specifically improves the heat transfer intensity of the flue gas inlet section (the area with the largest temperature difference and strongest heat transfer potential) and initially reduces the settling of large ash particles. The structure is simple, easy to operate, and less prone to failure. It requires no additional power, reducing manufacturing costs and complexity. Attached Figure Description

[0020] Figure 1 This is a first-view structural schematic diagram of the present invention; Figure 2 This is a schematic diagram of the second perspective structure of the present invention; Figure 3 This is a schematic diagram of the third-view structure of the present invention; Figure 4 This is a schematic diagram of the fourth perspective structure of the present invention; Figure 5 This is a first-view structural diagram of the internal components of the air inlet pipe of the present invention; Figure 6 This is a second-view structural diagram of the internal components of the air inlet pipe of the present invention; Figure 7 This is a schematic diagram of the internal component structure of the housing of the present invention; Figure 8 This is a schematic diagram of the internal heat exchange tube structure of the housing of the present invention; Figure 9 This is a first-view structural diagram of the connection between the fixing frame and the box body of the present invention; Figure 10 This is a second-view structural diagram of the connection between the fixing frame and the box body of the present invention; Figure 11 yes Figure 9 A magnified structural diagram at point A; Figure 12 yes Figure 9 A magnified structural diagram at point B; Figure 13 yes Figure 10 A magnified structural diagram at point C.

[0021] Reference numerals: 11. Housing; 12. Control panel; 13. Mounting bracket; 14. Air inlet pipe; 15. Exhaust pipe; 16. Water inlet pipe; 17. Motor No. 1; 18. Motor No. 2; 19. Drain pipe; 2. Flue gas velocity control assembly; 21. Paddle plate; 22. Gear; 23. Wedge plate; 24. Slide groove; 25. Limiting rod; 26. Notch; 3. Adjustable swing heat exchange assembly; 31. Heat exchange tube; 32. Metal tube No. 1; 33. Metal tube No. 2; 34. Connecting plate; 35. Slot; 36. Fixing bracket; 37. Cam; 38. Connecting rod; 39. Worm gear; 310. Worm No. 1; 311. Worm No. 2; 312. Moving part; 313. Sleeve plate; 314. Threaded rod; 315. Slide rod; 316. Connecting part; 317. Fixing rod. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] like Figures 1-8 As shown in this embodiment, an automatic waste heat recovery system for boiler flue gas includes a hollow housing 11. An inlet pipe 14 and an exhaust pipe 15 are installed on both sides of the housing 11. A control panel 12 is installed on one side of the outer wall of the housing 11, and a mounting bracket 13 is installed at the bottom of the housing 11. The inner wall of the housing 11 facing the inlet pipe 14 is arc-shaped. When the flue gas passes through the flue gas velocity control component 2, its velocity is increased, thus "pre-treating" the flue gas by using fluid shear force to remove some loose ash particles and prevent large particles from settling. Subsequently, the adjustable oscillating heat exchange component 3 performs "deep cleaning" on the heat exchange tubes 31, removing the more attached particles through mechanical oscillation. The tight ash accumulation achieves comprehensive and three-dimensional enhancement of the heat exchange process, ensuring that the heat exchange gain brought by the high-speed flue gas is not offset by the ash accumulation on the pipe wall and the stable boundary layer, but is further amplified by the swing component, thereby maximizing the overall heat transfer efficiency of the system. The inner wall of the box 11 is set in a conical shape on the side facing the exhaust pipe 15. At the same time, the top and bottom of the box 11 are respectively fixedly connected to the water inlet pipe 16 and the drain pipe 19. The flue gas velocity control component 2 is installed inside the air inlet pipe 14 to change the starting point and flow field distribution of the flue gas velocity. The flue gas velocity control component 2 includes a notch 26 that is opened through the top of the air inlet pipe 14, and a lever 21 is set in the notch 26.

[0024] like Figures 2-8 As shown, the paddle plate 21 is rotatably connected to the air inlet pipe 14, and the air inlet pipe 14 limits the movement of the paddle plate 21. The actuating part of the air inlet pipe 14 is located outside the air inlet pipe 14. The inner wall of the paddle plate 21 has several symmetrically distributed teeth, and gears 22 rotatably connected to the air inlet pipe 14 are provided at the teeth of the paddle plate 21. Wedge-shaped plates 23 are provided between the gears 22, and a sliding groove 24 is formed through the wedge-shaped plates 23. Two limiting rods 25, fixedly connected to the air inlet pipe 14, are provided inside the sliding groove 24. The limiting rods 25 are slidably connected to the sliding groove 24, and limit the sliding groove 24, causing the sliding groove 24 to slide axially along the limiting rods 25. The manual adjustment of the dial 21 allows for quick adjustment of the flow rate based on fluctuations in boiler flue gas flow and temperature (such as start-up, shutdown, and fuel switching). It adapts to different operating scenarios without complex control logic. The wedge plate 23 has several transmission teeth that mesh with the gear 22 on the side facing the gear 22. The wedge plate 23 is synchronously linked with the gear 22 through the transmission teeth. At the same time, several wedge plates 23 are slidably connected to each other. The gear 22 meshes with the dial 21, and the synchronous movement of the wedge plates 23 can adjust the flow field at the flue gas inlet, allowing the high-temperature flue gas to cover the surface of the heat exchange tube 31 more evenly. This avoids heat exchange dead zones caused by local flue gas short circuits or uneven flow rates, and improves the utilization rate of the heat exchange surface.

[0025] like Figures 1-13As shown, an adjustable swing heat exchange component 3 is installed inside the housing 11 to generate strong relative motion and convection between the high-temperature flue gas and the pipe wall, thereby improving the convective heat transfer coefficient. The adjustable swing heat exchange component 3 includes a heat exchange tube 31 located at the center of the inlet pipe 14 and the exhaust pipe 15. A second metal pipe 33 and a first metal pipe 32 are fixedly connected to the top and bottom of the heat exchange tube 31, respectively. The second metal pipe 33 and the first metal pipe 32 are corrugated pipe structures made of flexible metal material. The other ends of the first metal pipe 32 and the second metal pipe 33 are respectively fixedly installed to the drain pipe 19 and the water inlet pipe 16 at the bottom and top of the housing 11, respectively. A connecting plate 34 is fixedly installed on the inner wall of the heat exchange tube 31, and a slot 35 is opened through the middle of the connecting plate 34. A fixing frame 36 fixedly connected to the housing 11 is set inside the slot 35. Two worm gears 39 are rotatably connected to the top side of the fixing frame 36. The heat exchange tube 31 actively swings to break the surface of the stationary pipe wall. The stable insulating gas boundary layer causes strong relative motion between the high-temperature flue gas and the tube wall, reducing heat transfer resistance. The oscillation causes the water flow inside the tube to change from laminar flow to pulsating flow and turbulent flow, disrupting the water's thermal boundary layer and improving the heat transfer efficiency from the tube wall to the water. This solves the problem of weak heat transfer at the rear end caused by the thickened boundary layer of the traditional fixed heat exchange tube 31. The worm gear 39 is rotatably connected to the connecting shaft of the fixed frame 36, and the worm gear 39 is fixedly connected to the cam 37 at the end of the connecting shaft. The top of the two worm gears 39 is respectively connected to the first worm 310 and the second worm 311. One end of the second worm 311 is fixedly connected to the moving part 312. The inertial force of the oscillation of the heat exchange tube 31 will "throw" the accumulated dust that has been attached but not firmly bonded away from the tube wall, keeping the heat exchange surface clean for a long time, maintaining the designed heat exchange efficiency, and reducing maintenance costs. The first worm 310 is slidably connected to the moving part 312, and the moving part 312 is rotatably connected to the sleeve 313.

[0026] like Figures 2-13As shown, the other end of the sleeve 313 is threadedly connected to a threaded rod 314. A first motor 17 and a second motor 18 are respectively installed on both sides of the housing 11. The first motor 17 is located on the same side as the control panel 12. Drive shafts are installed at the output ends of the first motor 17 and the second motor 18, and these drive shafts are rotatably connected to the housing 11. The drive shaft at the output end of the first motor 17 is fixedly connected to the threaded rod 314, and the drive shaft at the output end of the second motor 18 is fixedly connected to the first worm gear 310. One end of the threaded rod 314 is rotatably connected to the fixing frame 36, and the other end of the threaded rod 314 is also rotatably connected to the fixing frame 36. The first worm gear 310 and the second worm gear 311 are slidably connected, and the first worm gear 310 axially limits the second worm gear 311. One end of the first worm gear 310 is rotatably connected to the fixing frame 36, and the first worm gear 310... The other end of the worm gear 310 is rotatably connected to the fixed frame 36. The oscillation of the heat exchange tube 31 can promote the heat exchange between the flue gas and the tube wall, making the wall temperature of each part of the tube bundle more uniform and avoiding local cold spots. At the same time, the oscillation can prevent or slow down the deposition of scale. Several cams 37 are rotatably connected to the top of the fixed frame 36, and the cams 37 are in pairs. The two cams 37 in a pair are mirror symmetrically arranged. The middle of the cam 37 is rotatably connected to the box body 11, and the bottom ends of the two cams 37 in a pair are rotatably connected to the connecting rod 38. At the same time, the other ends of the connecting rods 38 on both sides of the box body 11 are rotatably connected to two connecting pieces 316. The two connecting pieces 316 are rotatably connected to a fixed rod 317, and the middle of the connecting piece 316 is slidably connected to a sliding rod 315. The sliding rod 315 is fixedly connected to the box body 11. The connecting plate 34 is rotatably connected to the connecting rod 38 and the connecting piece 316.

[0027] The working principle of this embodiment is as follows: First, the air inlet pipe 14 on one side of the housing 11 is connected to the flue gas outlet of the boiler. Then, the exhaust pipe 15 on the other side of the housing 11 is connected to the external flue gas pipe. Then, the water inlet pipe 16 at the top of the housing 11 and the drain pipe 19 at the bottom are connected to the energy storage device to form a closed loop. Then, the high-temperature flue gas generated by the boiler during daily operation enters the housing 11 through the air inlet pipe 14. When it flows through the heat exchange tube 31, it exchanges heat with the heat exchange medium outside the tube. After absorbing the waste heat of the flue gas, the heat exchange tube 31 heats the water inside the heat exchange tube 31. The water then flows into the energy storage device through the drain pipe 19 at the bottom of the housing 11 via the No. 1 metal pipe 32, thus completing the heat energy recovery and utilization. The cooling water in the energy storage device flows back to the heat exchange tube 31 inside the housing 11 through the water inlet pipe 16, realizing the automatic recovery of waste heat of the boiler flue gas. After the flue gas temperature decreases, it is discharged through the exhaust pipe 15.

[0028] During routine waste heat recovery from flue gas, operators can manually rotate the dial plate 21, causing the internal gears of the dial plate 21 to drive several gears 22 to rotate synchronously. This causes the wedge plate 23 on the other side of the gear 22 to slide along the limiting rod 25 under the action of the limiting rod 25, thereby causing several wedge plates 23 to move synchronously. This adjusts the cross-sectional area of ​​the flue gas flow in the inlet pipe 14, increasing the flue gas velocity while keeping the flue gas volume flow rate constant. This enhances the convective heat transfer intensity between the flue gas and the heat exchange tube 31, improving the heat transfer efficiency of the initial section. At the same time, the higher flow velocity can carry more and larger ash particles through the heat exchange tube 31, reducing the settling on the heated surface. Furthermore, the high-speed flue gas has a stronger shearing force on the tube wall of the heat exchange tube 31, which can "blow away" loose ash, playing a certain role in online ash removal.

[0029] Meanwhile, staff can start motor 17 and motor 18 via control panel 12. When motor 18 is running, it can directly drive worm gear 310 to rotate. Since worm gear 310 limits worm gear 311, worm gear 310 drives worm gear 311 to rotate synchronously, which in turn causes the two worm wheels 39 to rotate simultaneously. This causes the two sets of cams 37 to rotate synchronously, driving the two connecting rods 38 to move up and down. At the same time, the two ends of the connecting rods 38 rotate relative to the cams 37 and the connecting piece 316, respectively. This causes the connecting plate 34, which is fixed to the heat exchange tube 31, to slide back and forth along the slide rod 315 through the connecting piece 316. This, in turn, causes the metal tube 32 and the metal tube 33 to extend and retract synchronously, making the heat exchange tube 31 move back and forth along the axial direction as a whole.

[0030] The operation of motor 17 directly drives the threaded rod 314 to rotate, thereby causing the sleeve 313 on the threaded rod 314 to move along the linear direction of the threaded rod 314. This, in turn, causes the moving part 312 on one side of the sleeve 313 to move along the linear direction of the first worm 310. The second worm 311 follows suit, changing the meshing position between the second worm 311 and the worm wheel 39. This causes the cam 37 connected to one side of the worm wheel 39 to rotate by a certain angle, thereby changing the reciprocating stroke of the two connecting rods 38. Furthermore, while adjusting the heat exchange tube 31 to move up and down reciprocally, the heat exchange tube 31 also oscillates axially, which disrupts the stable, heat-insulating gas boundary layer that would form on the surface of the stationary heat exchange tube 31. This causes strong relative motion and convection between the high-temperature flue gas and the tube wall of the heat exchange tube 31, which can significantly improve the convective heat transfer coefficient and reduce the required heat transfer area. Meanwhile, the water flow inside the heat exchange tube 31 changes from a stable laminar flow to a forced disturbance pulsating flow or turbulent flow, which also disrupts the thermal boundary layer of the water and improves the heat transfer efficiency from the tube wall to the water.

[0031] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. An automatic waste heat recovery system for boiler flue gas, comprising a hollow-structured box (11), with an inlet pipe (14) and an exhaust pipe (15) installed on both sides of the box (11), and a control panel (12) installed on one side of the outer wall of the box (11), characterized in that: The bottom of the box (11) is equipped with a mounting bracket (13). The inner wall of the box (11) is set in an arc shape on the side facing the air inlet pipe (14), and the inner wall of the box (11) is set in a conical shape on the side facing the exhaust pipe (15). Meanwhile, the top and bottom of the box (11) are respectively connected to a water inlet pipe (16) and a drain pipe (19). The inlet pipe (14) is equipped with a flue gas velocity control component (2) to change the starting point and flow field distribution of the flue gas velocity. The box (11) is equipped with an adjustable swing heat exchange component (3) to generate strong relative motion and convection between high temperature flue gas and pipe wall, thereby improving the convective heat transfer coefficient.

2. The automatic waste heat recovery system for boiler flue gas according to claim 1, characterized in that, The flue gas flow rate control component (2) includes a notch (26) that runs through the top of the air inlet pipe (14), and a lever (21) is provided in the notch (26). The lever (21) is rotatably connected to the air inlet pipe (14), and the air inlet pipe (14) limits the lever (21). At the same time, the lever part of the air inlet pipe (14) is located outside the air inlet pipe (14). The inner wall of the lever (21) is provided with a number of teeth that are symmetrically distributed in a circle, and a gear (22) that is rotatably connected to the air inlet pipe (14) is provided at the teeth of the lever (21). At the same time, the gear (22) meshes with the lever (21).

3. The automatic waste heat recovery system for boiler flue gas according to claim 2, characterized in that, A wedge plate (23) is provided between several gears (22), and a groove (24) is provided through the wedge plate (23). At the same time, two limiting rods (25) are provided inside the groove (24) and are fixedly connected to the air inlet pipe (14). The limiting rods (25) are slidably connected to the groove (24), and the limiting rods (25) limit the groove (24) so ​​that the groove (24) slides along the axial direction of the limiting rods (25). A number of transmission teeth that mesh with the gears (22) are provided on the side of the wedge plate (23) facing the gears (22), and the wedge plate (23) is synchronously linked with the gears (22) through the transmission teeth. At the same time, the wedge plates (23) are slidably connected to each other.

4. The automatic waste heat recovery system for boiler flue gas according to claim 1, characterized in that, The adjustable swing heat exchange assembly (3) includes a heat exchange tube (31) located at the center of the air inlet pipe (14) and the exhaust pipe (15). The top and bottom of the heat exchange tube (31) are respectively fixedly connected to a second metal tube (33) and a first metal tube (32). The second metal tube (33) and the first metal tube (32) are corrugated pipe structures made of flexible metal material. The other ends of the first metal tube (32) and the second metal tube (33) are respectively installed and fixed to the drain pipe (19) and the water inlet pipe (16) at the bottom and top of the box body (11). A connecting plate (34) is installed and fixed on the inner wall of the heat exchange tube (31). A slot (35) is opened through the middle of the connecting plate (34). A fixing frame (36) fixedly connected to the box body (11) is provided inside the slot (35).

5. The automatic waste heat recovery system for boiler flue gas according to claim 4, characterized in that, The top of the fixed frame (36) is rotatably connected to several cams (37), and the several cams (37) are in pairs. At the same time, the two cams (37) in a group are mirror-symmetrically arranged. The middle part of the cam (37) is rotatably connected to the box body (11), and the bottom ends of the two cams (37) in a group are rotatably connected to a connecting rod (38). At the same time, the other ends of the connecting rods (38) on both sides of the box body (11) are rotatably connected to two connecting pieces (316). The two connecting pieces (316) are rotatably connected to a fixed rod (317), and a sliding rod (315) is slidably connected through the middle of the connecting piece (316). At the same time, the sliding rod (315) is connected and fixed to the box body (11). The connecting plate (34) is rotatably connected through the connecting rod (38) and the connecting piece (316).

6. The automatic waste heat recovery system for boiler flue gas according to claim 5, characterized in that, Two worm gears (39) are rotatably connected to one side of the top of the fixed frame (36), and the connecting shaft of the worm gears (39) is rotatably connected to the fixed frame (36) through it. At the same time, the connecting end of the worm gears (39) is connected and fixed to the cam (37). The top of the two worm gears (39) are respectively connected to a first worm (310) and a second worm (311), and the first worm (310) and the second worm (311) are slidably connected through it. At the same time, the first worm (310) axially limits the second worm (311). One end of the first worm (310) is rotatably connected to the fixed frame (36), and the other end of the first worm (310) is rotatably connected to the fixed frame (36).

7. The automatic waste heat recovery system for boiler flue gas according to claim 6, characterized in that, One end of the second worm (311) is fixedly connected to a movable part (312), and the first worm (310) is slidably connected to the movable part (312). At the same time, a sleeve plate (313) is rotatably connected inside the movable part (312). The other end of the sleeve plate (313) is threadedly connected to a threaded rod (314), and one end of the threaded rod (314) is rotatably connected to the fixed frame (36). At the same time, the other end of the threaded rod (314) is rotatably connected to the fixed frame (36).

8. The automatic waste heat recovery system for boiler flue gas according to claim 7, characterized in that, The housing (11) is equipped with a No. 1 motor (17) and a No. 2 motor (18) on both sides. The No. 1 motor (17) and the control panel (12) are located on the same side. The output ends of the No. 1 motor (17) and the No. 2 motor (18) are equipped with drive shafts. The drive shafts at the output ends of the No. 1 motor (17) and the No. 2 motor (18) are rotatably connected through the housing (11). The through end of the drive shaft at the output end of the No. 1 motor (17) is connected and fixed to the threaded rod (314). The through end of the drive shaft at the output end of the No. 2 motor (18) is connected and fixed to the No. 1 worm gear (310).

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