A multi-stage waste heat deep recovery and utilization device for biomass boiler flue gas

Abstract

This invention relates to the field of boiler flue gas recovery technology and discloses a multi-stage waste heat recovery and utilization device for biomass boiler flue gas. The device includes a furnace body with an outer shell on the front side. A waste heat recovery mechanism is located inside the outer shell, comprising multiple heat exchange tubes equidistantly and fixedly connected to the inner side of the outer shell. A water pipe is connected to the top of the right-side heat exchange tube, a conveying pipe (first) is connected to the top of the middle heat exchange tube, and a conveying pipe (second) is connected to the top of the left-side heat exchange tube. By setting multiple heat exchange tubes, the flue gas generated during combustion passes sequentially through the right, middle, and left heat exchange tubes. The right-side heat exchange tube provides high-grade heat energy feedback to reduce fuel consumption in the boiler body. The middle heat exchange tube increases the overall reference temperature and combustion efficiency of the furnace. The left-side heat exchange tube performs preliminary drying on the biomass fuel on the conveyor belt before it enters the furnace.

Description

Technical Field

[0001] This invention relates to the field of boiler flue gas recovery technology, specifically to a multi-stage waste heat recovery and utilization device for biomass boiler flue gas. Background Technology

[0002] Biomass boilers are special thermal energy equipment that uses biomass energy as fuel for combustion and heat exchange. With the increasing global emphasis on environmental protection and renewable energy, biomass boilers have been widely used in industrial production, district heating and power generation due to their carbon neutrality, environmental protection attributes and wide availability of fuel.

[0003] However, during the operation of biomass boilers, the intense combustion of biomass fuel in the furnace produces a large amount of high-temperature flue gas. When this high-temperature flue gas is discharged into the tail flue after completing the heat exchange of the boiler body, it usually still carries extremely high temperature and a large amount of sensible heat. If this high-temperature flue gas is directly discharged into the atmosphere, it will cause serious waste of heat energy and reduce the overall thermal efficiency of the boiler. Therefore, it is necessary to extract and utilize the heat in the flue gas in a secondary manner.

[0004] Existing waste heat recovery devices for biomass boilers typically consist of a single heat exchanger tube bundle installed within the flue, through which boiler feedwater flows. High-temperature flue gas transfers heat to the water as it passes through the heat exchanger tubes, and the heated water is then sent to the steam drum. However, a single heat exchanger can only absorb relatively high-grade heat energy; the flue gas temperature remains high after a single heat exchange, and direct discharge results in heat waste, failing to achieve cascaded utilization of heat energy. To address this issue, existing technology adds an air preheater in series after the water heat exchanger, using the cooled, medium-temperature flue gas to heat the surrounding cold air. Hot air is then blown into the furnace as combustion air. However, biomass fuel itself is loose in texture and usually contains a high amount of moisture. Directly sending untreated water-containing fuel into the furnace will cause the moisture to evaporate and absorb a large amount of heat, thereby lowering the overall reference temperature of the furnace and affecting the combustion effect and combustion rate of the biomass fuel. Furthermore, the existing two-stage waste heat recovery device only focuses on heating water and combustion air, resulting in the waste of heat energy at the end of the flue gas. It also cannot fundamentally solve the problem of high boiler fuel consumption and low combustion efficiency caused by water-containing biomass fuel entering the furnace. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a multi-stage waste heat recovery and utilization device for biomass boiler flue gas. This solves the problem that existing waste heat recovery devices cannot pre-dry water-containing biomass fuel before it enters the furnace, resulting in the direct entry of wet fuel into the furnace, where water evaporates and absorbs a large amount of heat, lowering the furnace temperature and causing high fuel consumption and low combustion efficiency in the boiler body.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a multi-stage waste heat recovery and utilization device for biomass boiler flue gas, comprising a furnace body, an outer shell provided on the front side of the furnace body, a feed box fixedly connected to the left side of the furnace body, a waste heat recovery mechanism provided on the inner side of the outer shell, a cleaning mechanism provided on the top of the outer shell, and an adjustment mechanism provided in the middle of the inner side of the outer shell.

[0007] The waste heat recovery mechanism includes multiple heat exchange tubes, which are fixedly connected at equal intervals to the inner side of the outer shell. The top of the heat exchange tube on the right side is connected to a water supply pipe, the top of the heat exchange tube in the middle is connected to a conveying pipe one, and the top of the heat exchange tube on the left side is connected to a conveying pipe two. The outer sides of the water supply pipe, conveying pipe one, and conveying pipe two all penetrate the outer shell. The left end of conveying pipe two is connected to the bottom of the feed box. A steam drum is provided on the top of the furnace body, and the top of the water supply pipe is connected to the steam drum. The front side of the left wall of the furnace body is connected to the furnace air inlet, and the left end of conveying pipe one is connected to the furnace air inlet.

[0008] Preferably, the cleaning mechanism includes multiple brackets, which are equidistantly fixedly connected to the top of the outer shell. A rotating rod is rotatably connected to the top inner side of each bracket, and a support plate is fixedly connected to the bottom of the rotating rod. A plug-in post is fixedly connected to the bottom rear side of the support plate. Multiple support blocks are equidistantly fixedly connected to the front and rear sides of the top of the outer shell. L-shaped rods are slidably connected to the inner sides of the front and rear support blocks. The same frame is fixedly connected to adjacent ends of the front and rear L-shaped rods. The outer side of the plug-in post is slidably connected to the inside of the frame. The same support rod is fixedly connected to the bottom of the front and rear L-shaped rods. The outer side of the support rod penetrates the outer shell. Two outer frames are fixedly connected to the left side of the support rod, and multiple scrapers are fixedly connected to the inner side of the outer frames.

[0009] Preferably, the adjustment mechanism includes a U-shaped plate, which is fixedly connected to the top center of the furnace body. A bidirectional threaded rod is rotatably connected to the inner side of the U-shaped plate. Movable plates are threadedly connected to the front and rear sides of the outer wall of the bidirectional threaded rod. Connecting rods are fixedly connected to the bottom of adjacent sides of the two movable plates. Back plates are fixedly connected to the front and rear ends of the inner center of the outer shell 5. Baffles are rotatably connected to adjacent sides of the two back plates. Sliding grooves are provided on the opposite sides of the two baffles. Sliding sliders are slidably connected to the inner side of the sliding grooves. Adjacent ends of the two connecting rods penetrate the outer shell and are rotatably connected to the corresponding sliding sliders.

[0010] Preferably, the waste heat recovery mechanism further includes a delivery pump, which is fixedly connected to the bottom right side of the outer casing, and the bottom of the heat exchange tube on the right side penetrates the outer casing and is connected to the output end of the delivery pump.

[0011] Preferably, the waste heat recovery mechanism further includes an air inlet pipe 1, which is connected to the lower side of the heat exchange tube in the middle, and an air inlet pipe 2 is connected to the bottom of the heat exchange tube on the left side. The bottom ends of both the air inlet pipe 1 and the air inlet pipe 2 penetrate the outer shell.

[0012] Preferably, the waste heat recovery mechanism further includes a conveyor belt, which is disposed at the bottom inner side of the feed box, and the feed box has a feed inlet connected to the top left side.

[0013] Preferably, a connecting pipe is connected to the right side of the furnace body, the front end of the connecting pipe is connected to the outer shell, and a smoke outlet is connected to the left side of the outer shell.

[0014] Preferably, the cleaning mechanism further includes a motor, which is fixedly connected to the top left side of the housing. The output end of the motor is fixedly connected to a drive shaft, and multiple worm gears are fixedly connected at equal intervals to the outer side of the drive shaft. A worm wheel is fixedly connected to the middle of the outer side of each of the multiple rotating rods, and the worm gears and worm wheels are meshed together.

[0015] Preferably, the front end of the bidirectional threaded rod passes through the U-shaped plate, and the outer side of the movable plate is slidably connected to the inner wall of the U-shaped plate.

[0016] Preferably, the adjusting mechanism further includes a sealing gasket, which is sleeved on the outside of the connecting rod, and one side of the sealing gasket is fixedly connected to the outer shell.

[0017] This invention provides a multi-stage waste heat recovery and utilization device for biomass boiler flue gas. It has the following beneficial effects:

[0018] 1. This invention uses multiple heat exchange tubes inside the outer shell, allowing the flue gas generated during combustion to pass sequentially through the right, middle, and left heat exchange tubes. The right heat exchange tube uses the high-temperature flue gas to heat the room-temperature water pumped in by the delivery pump, and then delivers it to the steam drum via the water pipe, achieving high-grade heat energy feedback to reduce the fuel consumption of the boiler body. The middle heat exchange tube uses the cooled flue gas to heat the air pumped in by the first air inlet pipe, and then delivers it to the air inlet of the furnace via the first delivery pipe, improving the overall reference temperature of the furnace and the combustion efficiency. The left heat exchange tube uses the further cooled flue gas to heat the gas pumped in by the second air inlet pipe into hot air, and then delivers it to the feed box via the second delivery pipe, preliminarily drying the biomass fuel that is about to enter the furnace body on the conveyor belt, thereby improving the combustion efficiency of the biomass fuel.

[0019] 2. This invention uses a motor to drive the transmission shaft and worm gear to rotate. The worm gear meshes with the worm wheel, which in turn drives the rotating rod and support plate to rotate, causing the plug-in column to move in a circular motion. This drives the frame to move linearly back and forth, and the frame then drives the L-shaped rod to move, which in turn drives the outer frame to move the scraper synchronously. This removes the ash or coke adhering to the surface of the heat exchange tube, effectively removing the dirt layer that hinders heat conduction. This achieves automated cleaning of the outer wall of the heat exchange tube, keeping the heat exchange tube always exposed and preventing the heat exchange efficiency from decreasing due to coking on the tube wall.

[0020] 3. This invention drives the movable plates on both sides of the bidirectional threaded rod to move towards each other or away from each other by rotating the bidirectional threaded rod. When the movable plates move, they drive the slider to move synchronously through the connecting rod. The movement of the slider will push the baffle to rotate, so that the baffles on both sides can close or open. This allows for dynamic adjustment of the size of the flue gas interception surface inside the shell, thereby regulating the flue gas flow rate inside the shell. By changing the flow rate, the heat exchange efficiency of multiple heat exchange tubes can be controlled, enabling the waste heat recovery device to adapt to the usage requirements of biomass boilers at different combustion stages and under different operating conditions. Attached Figure Description

[0021] Figure 1 This is a perspective view of the present invention;

[0022] Figure 2 This is a side view of the present invention;

[0023] Figure 3 This is a partial structural cross-sectional view of the present invention;

[0024] Figure 4 This is a partial structural cross-sectional view of the waste heat recovery mechanism of the present invention;

[0025] Figure 5 This is a partial structural diagram of the present invention;

[0026] Figure 6 This is a partial structural diagram of the cleaning mechanism of the present invention;

[0027] Figure 7 This is a partial structural cross-sectional view of the adjustment mechanism of the present invention;

[0028] Figure 8 for Figure 7 Enlarged view of point A in the image.

[0029] The components include: 1. Furnace body; 2. Waste heat recovery mechanism; 21. Heat exchanger tube; 22. Water supply pipe; 23. Conveying pipe one; 24. Conveying pipe two; 25. Feed inlet; 26. Conveying pump; 27. Air inlet one; 28. Air inlet two; 29. ​​Steam drum; 210. Furnace air inlet; 211. Conveyor belt; 3. Cleaning mechanism; 31. Support; 32. Rotating rod; 33. Support plate; 34. Insertion column; 35. Support block; 36. L-shaped... 37. Rod; 38. Frame; 39. Support rod; 30. Outer frame; 310. Scraper; 311. Motor; 312. Drive shaft; 313. Worm; 314. Worm wheel; 4. Adjustment mechanism; 41. U-shaped plate; 42. Bidirectional threaded rod; 43. Movable plate; 44. Connecting rod; 45. Back plate; 46. Baffle; 47. Slide groove; 48. Slider; 49. Sealing gasket; 5. Outer shell; 6. Connecting pipe; 7. Feed box; 8. Smoke outlet. Detailed Implementation

[0030] The technical solutions in 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Reference Figure 2 , Figure 3 and Figure 4 This invention provides a multi-stage waste heat recovery and utilization device for biomass boiler flue gas, including a furnace body 1, an outer shell 5 on the front side of the furnace body 1, a feed box 7 fixedly connected to the left side of the furnace body 1, a waste heat recovery mechanism 2 on the inner side of the outer shell 5, a cleaning mechanism 3 on the top of the outer shell 5, and an adjustment mechanism 4 in the middle of the inner side of the outer shell 5.

[0032] The waste heat recovery mechanism 2 includes multiple heat exchange tubes 21, which are equidistantly fixedly connected to the inner side of the outer shell 5. The top of the right-side heat exchange tube 21 is connected to a water supply pipe 22, the top of the middle heat exchange tube 21 is connected to a first conveying pipe 23, and the top of the left-side heat exchange tube 21 is connected to a second conveying pipe 24. The outer sides of the water supply pipe 22, the first conveying pipe 23, and the second conveying pipe 24 all penetrate the outer shell 5. The left end of the second conveying pipe 24 is connected to the bottom of the feed box 7. The furnace body 1... A steam drum 29 is installed at the top of the furnace body 1. The top of the water pipe 22 is connected to the steam drum 29. Water flows into the heat exchange pipe 21 on the right side. The heated high-temperature water can be input into the steam drum 29 through the water pipe 22. The furnace body 1 has a furnace air inlet 210 connected to the front left wall. The left end of the conveying pipe 23 is connected to the furnace air inlet 210. The waste heat recovery mechanism 2 also includes a conveying pump 26, which is fixedly connected to the bottom right side of the outer shell 5. The right heat exchange pipe 21... The bottom of the outer shell 5 is connected to the output end of the conveying pump 26. The waste heat recovery mechanism 2 also includes an air inlet pipe 27, which is connected to the lower side of the middle heat exchange pipe 21. The bottom of the left heat exchange pipe 21 is connected to an air inlet pipe 28. The bottom ends of the air inlet pipe 27 and the air inlet pipe 28 both penetrate the outer shell 5. The air inlet pipe 27 and the air inlet pipe 28 are both connected to the external gas supply pipe to introduce external gas. The waste heat recovery mechanism 2 also includes a conveyor belt 211, which is set at the bottom of the inner side of the feed box 7. The top left side of the feed box 7 is connected to the feed port 25, through which biomass fuel can be put in and conveyed into the furnace body 1 by the conveyor belt 211. The right side of the furnace body 1 is connected to the connecting pipe 6, the front end of the connecting pipe 6 is connected to the outer shell 5, and the left side of the outer shell 5 is connected to the flue gas outlet 8. The connecting pipe 6 can send high-temperature flue gas into the outer shell 5, and the flue gas in the outer shell 5 can be sent out through the flue gas outlet 8.

[0033] Specifically, when using a biomass boiler, biomass fuel is fed into the feed box 7 through the feed inlet 25. The conveyor belt 211 transports the biomass fuel from the bottom of the feed box 7 into the combustion chamber inside the furnace body 1 for oxidation and combustion. The high-temperature flue gas generated by the combustion reaction carries a large amount of heat energy and enters the outer shell 5 through the connecting pipe 6 under the action of the furnace pressure difference. Inside the outer shell 5, multiple sets of heat exchange tubes 21 are arranged sequentially along the flue gas flow direction. In the right heat exchange tube 21, which is the first to come into contact with the inlet high-temperature flue gas, room temperature water is pumped in by the delivery pump 26. As the room temperature water flows in the tube, it absorbs the heat carried by the high-temperature flue gas and changes from room temperature to high-temperature hot water. The delivery pump 26 then delivers this heated water to the boiler drum 29 through the water pipe 22 to supplement the heat of the boiler working fluid and reduce the fuel consumption of the furnace body 1 itself. The temperature of the flue gas decreases after passing through the right heat exchange tube 21 and continues to flow to the middle heat exchange tube 21. At this time, the inlet pipe Ambient air drawn in from the outside is pumped into the internal channel of the central heat exchange tube 21. As the cold air flows through the tube, it exchanges heat with the medium-temperature flue gas outside the tube, raising the air temperature to high-temperature combustion air. Then, it is directly pumped to the furnace air inlet 210 through the conveying pipe 23 to enter the furnace and participate in combustion. After preheating, the combustion air carries a higher enthalpy value into the furnace, raising the initial temperature of the combustion zone and creating favorable conditions for the complete combustion of fuel. After the flue gas passes through the central heat exchange tube 21, its temperature is further reduced. Finally, it flows through the left heat exchange tube 21. The gas pumped in from the outside through the air inlet pipe 28 flows through the left heat exchange tube 21 and is heated to form hot air. This hot air is transported back to the inside of the feed box 7 through the conveying pipe 24 and blows onto the biomass fuel being conveyed on the conveyor belt 211. This pre-drying process evaporates the moisture contained in the fuel, reducing the moisture content of the fuel and making the fuel entering the furnace body 1 easier to ignite and burn more completely.

[0034] Reference Figure 1 , Figure 5 and Figure 6The cleaning mechanism 3 includes multiple brackets 31, which are equidistantly fixedly connected to the top of the outer casing 5. A rotating rod 32 is rotatably connected to the top inner side of each bracket 31. A support plate 33 is fixedly connected to the bottom of the rotating rod 32. A plug-in post 34 is fixedly connected to the bottom rear side of the support plate 33. The support plate 33 can drive the plug-in post 34 to perform circular motion. Multiple support blocks 35 are equidistantly fixedly connected to the front and rear sides of the top of the outer casing 5. L-shaped rods 36 are slidably connected to the inner sides of the front and rear support blocks 35. The same frame 37 is fixedly connected to adjacent ends of the front and rear L-shaped rods 36. The outer side of the plug-in post 34 is slidably connected to the inner side of the frame 37. When the plug-in post 34 moves in a circular motion, it pushes the frame 37 to reciprocate. The same support rod 34 is fixedly connected to the bottom of the front and rear L-shaped rods 36. 8. The outer side of the support rod 38 penetrates the outer shell 5. Two outer frames 39 are fixedly connected to the left side of the support rod 38. The L-shaped rod 36 can support the movement, thereby driving the outer frames 39 to move. Multiple scrapers 310 are fixedly connected to the inner side of the outer frames 39. The outer frames 39 can drive the scrapers 310 to move. The cleaning mechanism 3 also includes a motor 311. The motor 311 is fixedly connected to the top left side of the outer shell 5. The output end of the motor 311 is fixedly connected to a transmission shaft 312. Multiple worm gears 313 are fixedly connected at equal intervals to the outer side of the transmission shaft 312. Worm wheels 314 are fixedly connected to the middle of the outer side of multiple rotating rods 32. The worm gears 313 and worm wheels 314 are meshed and connected. The motor 311 drives the transmission shaft 312 to rotate, and through the transmission action of the worm gears 313 and worm wheels 314, drives the rotating rods 32 to rotate.

[0035] Specifically, during the continuous flushing of the heat exchange tube 21 by the flue gas, ash particles in the flue gas adhere to the outer wall of the heat exchange tube 21 and form a coking layer. At this time, the motor 311 is started, and the motor 311 drives the worm gear 313 to rotate through the transmission shaft 312, which in turn drives the worm wheel 314 meshing with the worm gear 313 to rotate. The worm wheel 314 will then drive the rotating rod 32 to rotate. The rotation of the rotating rod 32 will drive the support plate 33 to rotate synchronously. The rotation of the support plate 33 will drive the eccentrically set insertion post 34 to rotate circumferentially. The insertion post 34 will then drive the frame 37 to reciprocate. In linear motion, as the frame 37 moves, the L-shaped rod 36 fixed on it pushes the connected support rod 38 to move synchronously. The support rod 38 pushes the outer frame 39 to move, causing the scraper 310 fixed on the outer frame 39 to reciprocate along the axis of the heat exchange tube 21. The cutting edge of the scraper 310 is in close contact with the outer wall of the heat exchange tube 21. During the reciprocating movement, it removes and falls off the ash or coke adhering to the tube wall, exposing the metal surface of the heat exchange tube 21 again, thereby maintaining efficient heat transfer performance and avoiding the continuous decline in heat exchange efficiency caused by coking.

[0036] Reference Figure 3 , Figure 7 and Figure 8The adjusting mechanism 4 includes a U-shaped plate 41, which is fixedly connected to the top center of the furnace body 1. A bidirectional threaded rod 42 is rotatably connected to the inner side of the U-shaped plate 41. Movable plates 43 are threadedly connected to the front and rear sides of the outer wall of the bidirectional threaded rod 42. When the bidirectional threaded rod 42 rotates, it drives the movable plates 43 to move. A connecting rod 44 is fixedly connected to the bottom of the adjacent side of the two movable plates 43. A back plate 45 is fixedly connected to the front and rear ends of the inner center of the outer shell 5. A connecting rod 44 is rotatably connected to the adjacent side of the two back plates 45. The baffle 46 has a groove 47 on the opposite side of each baffle 46. A slider 48 is slidably connected to the inner side of the groove 47. The adjacent ends of the two connecting rods 44 pass through the outer shell 5 and are rotatably connected to the corresponding slider 48. The movable plate 43 will drive the connecting rod 44 to move. The connecting rod 44 will push the baffle 46 to rotate through the slider 48. The front end of the bidirectional threaded rod 42 passes through the U-shaped plate 41, which makes it convenient for the operator to rotate the bidirectional threaded rod 42. The outer side of the movable plate 43 is slidably connected to the inner wall of the U-shaped plate 41.

[0037] Specifically, during equipment operation, the flue gas velocity is adjusted by rotating the bidirectional threaded rod 42. When the bidirectional threaded rod 42 is rotated, the movable plates 43 on both sides move towards each other or away from each other. The movement of each movable plate 43 is pushed by the connecting rod 44 to move the slider 48. The slider 48 is slidably connected to the groove 47 opened in the side wall of the baffle 46. When the slider 48 moves, it pushes the baffle 46 to rotate, so that the baffles 46 on both sides of the flue gas duct close or open simultaneously, changing the effective cross-sectional area of ​​the flue gas flow channel inside the shell 5, and changing the overall flow velocity of the flue gas when it passes through the shell 5. By actively adjusting the flue gas velocity, the contact time and heat exchange intensity between the flue gas and each group of heat exchange tubes 21 can be precisely controlled to adapt to the requirements of different biomass fuel types or different boiler combustion load stages for waste heat recovery efficiency.

[0038] Reference Figure 7 and Figure 8 The adjusting mechanism 4 also includes a sealing gasket 49, which is sleeved on the outside of the connecting rod 44, and one side of the sealing gasket 49 is fixedly connected to the outer shell 5.

[0039] Specifically, the sealing gasket 49 prevents smoke from leaking from the gap between the connecting rod 44 and the housing 5, thus improving the practicality of the device.

[0040] Working principle:

[0041] When using a biomass boiler, biomass fuel is fed into the feed box 7 through the feed inlet 25. The conveyor belt 211 then transports the fuel into the furnace body 1 for combustion. The resulting flue gas enters the outer shell 5 through the connecting pipe 6. Multiple heat exchange tubes 21 are installed inside the outer shell 5. The right-side heat exchange tube 21 is the first to contact the high-temperature flue gas. Room-temperature water is pumped into the right-side heat exchange tube 21 by the delivery pump 26. After contacting the high-temperature flue gas, the room-temperature water's temperature increases significantly. The heated water is then pumped through the delivery pump 26 to the steam drum 29 via the water pipe 22. The significant increase in water temperature entering the steam drum 29 reduces fuel consumption in the boiler body, achieving efficient feedback of high-grade heat energy. The temperature of the flue gas decreases after passing through the right-side heat exchange tube 21. The air passes through the central heat exchange tube 21, through which air is pumped in via the inlet pipe 27. The cold air passes through the central heat exchange tube 21, where its temperature increases significantly. It is then pumped into the furnace air inlet 210 via the conveying pipe 23 and enters the furnace. This process heats the airflow into the furnace, raising the overall reference temperature of the furnace and improving combustion efficiency. The flue gas temperature decreases further after passing through the central heat exchange tube 21 and comes into contact with the left heat exchange tube 21. The left heat exchange tube 21 pumps in external gas through the inlet pipe 28, which is then heated by the heat exchange tube 21 and becomes hot air. This hot air is then conveyed into the feed box 7 via the conveying pipe 24, where the biomass fuel conveyed on the conveyor belt 211 is preliminarily dried, evaporating the moisture in the biomass fuel and improving its combustion efficiency.

[0042] Furthermore, when the flue gas passes through the heat exchange tube 21, coking will gradually occur on the outer side of the heat exchange tube 21. At this time, the motor 311 is started. The motor 311 drives the worm 313 to rotate through the transmission shaft 312. Since the worm 313 meshes with the worm wheel 314, the worm 313 can drive the rotating rod 32 to rotate through the worm wheel 314. The rotating rod 32 will drive the support plate 33 to rotate, which in turn drives the plug-in column 34 to perform circumferential motion. When the plug-in column 34 moves, it will push the frame 37 to move back and forth. The frame 37 can push the support rod 38 to move through the L-shaped rod 36. The support rod 38 will drive the outer frame 39 to move, which in turn drives the scraper 310 to move. When the scraper 310 moves, it can scrape off the ash or coke attached to the heat exchange tube 21, keeping the heat exchange tube 21 in an exposed state and ensuring that the heat exchange efficiency does not decrease.

[0043] Finally, by rotating the bidirectional threaded rod 42, the movable plates 43 on both sides will move towards each other or away from each other. When the movable plates 43 move, they can push the slider 48 to move through the connecting rod 44. Since the slider 48 slides in the groove 47 opened on one side of the baffle 46, the slider 48 will push the baffle 46 to rotate when it moves. By rotating the bidirectional threaded rod 42, the baffles 46 on both sides can be closed or opened, thereby adjusting the cross-sectional area in the outer shell 5. This allows the flue gas velocity in the outer shell 5 to be adjusted. By adjusting the flue gas velocity, the heat exchange efficiency of multiple heat exchange tubes 21 can be adjusted to adapt to different combustion stages.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-stage waste heat recovery and utilization device for biomass boiler flue gas, comprising a furnace body (1), characterized in that, The furnace body (1) is provided with an outer shell (5) on the front side, a feed box (7) is fixedly connected to the left side of the furnace body (1), a waste heat recovery mechanism (2) is provided on the inner side of the outer shell (5), a cleaning mechanism (3) is provided on the top of the outer shell (5), and an adjustment mechanism (4) is provided in the middle of the inner side of the outer shell (5). The waste heat recovery mechanism (2) includes multiple heat exchange tubes (21), which are fixedly connected at equal intervals to the inner side of the outer shell (5). The top of the heat exchange tube (21) on the right side is connected to a water supply pipe (22), the top of the heat exchange tube (21) in the middle is connected to a first conveying pipe (23), and the top of the heat exchange tube (21) on the left side is connected to a second conveying pipe (24). The outer sides of the water supply pipe (22), the first conveying pipe (23), and the second conveying pipe (24) all penetrate the outer shell (5). The left end of the second conveying pipe (24) is connected to the bottom of the feed box (7). A steam drum (29) is provided on the top of the furnace body (1). The top of the water supply pipe (22) is connected to the steam drum (29). The front side of the left wall of the furnace body (1) is connected to the furnace air inlet (210). The left end of the first conveying pipe (23) is connected to the furnace air inlet (210).

2. The multi-stage waste heat recovery and utilization device for biomass boiler flue gas according to claim 1, characterized in that, The cleaning mechanism (3) includes multiple brackets (31), which are equidistantly fixedly connected to the top of the outer shell (5). A rotating rod (32) is rotatably connected to the top inner side of each bracket (31), and a support plate (33) is fixedly connected to the bottom of the rotating rod (32). A plug-in post (34) is fixedly connected to the rear bottom of the support plate (33). Multiple support blocks (35) are equidistantly fixedly connected to the front and rear sides of the top of the outer shell (5). The inner sides of the support blocks (35) on the front and rear sides are slidable. An L-shaped rod (36) is dynamically connected. The adjacent ends of the L-shaped rod (36) on the front and rear sides are fixedly connected to the same frame (37). The outer side of the plug-in post (34) is slidably connected to the inside of the frame (37). The bottom of the L-shaped rod (36) on the front and rear sides is fixedly connected to the same support rod (38). The outer side of the support rod (38) penetrates the outer shell (5). Two outer frames (39) are fixedly connected to the left side of the support rod (38). Multiple scrapers (310) are fixedly connected to the inner side of the outer frames (39).

3. The multi-stage waste heat recovery and utilization device for biomass boiler flue gas according to claim 1, characterized in that, The adjustment mechanism (4) includes a U-shaped plate (41), which is fixedly connected to the top center of the furnace body (1). A bidirectional threaded rod (42) is rotatably connected to the inner side of the U-shaped plate (41). Movable plates (43) are threadedly connected to the front and rear sides of the outer wall of the bidirectional threaded rod (42). A connecting rod (44) is fixedly connected to the bottom of the adjacent side of the two movable plates (43). A back plate (45) is fixedly connected to the front and rear ends of the inner center of the outer shell (5). A baffle (46) is rotatably connected to the adjacent side of the two back plates (45). A sliding groove (47) is opened on the opposite side of the two baffles (46). A slider (48) is slidably connected to the inner side of the sliding groove (47). An adjacent end of the two connecting rods (44) passes through the outer shell (5) and is rotatably connected to the corresponding slider (48).

4. The multi-stage waste heat recovery and utilization device for biomass boiler flue gas according to claim 1, characterized in that, The waste heat recovery mechanism (2) also includes a delivery pump (26), which is fixedly connected to the bottom right side of the outer shell (5). The bottom of the heat exchange tube (21) on the right side penetrates the outer shell (5) and is connected to the output end of the delivery pump (26).

5. The multi-stage waste heat recovery and utilization device for biomass boiler flue gas according to claim 1, characterized in that, The waste heat recovery mechanism (2) also includes an air inlet pipe (27), which is connected to the lower side of the heat exchange tube (21) in the middle, and an air inlet pipe (28) is connected to the bottom of the heat exchange tube (21) on the left side. The bottom ends of the air inlet pipe (27) and the air inlet pipe (28) both penetrate the outer shell (5).

6. The multi-stage waste heat recovery and utilization device for biomass boiler flue gas according to claim 1, characterized in that, The waste heat recovery mechanism (2) also includes a conveyor belt (211), which is located at the bottom of the inner side of the feed box (7), and the feed box (7) has a feed inlet (25) connected to the top left side.

7. The multi-stage waste heat recovery and utilization device for biomass boiler flue gas according to claim 1, characterized in that, The furnace body (1) has a connecting pipe (6) on its right side, the front end of which is connected to the outer shell (5), and the outer shell (5) has a smoke outlet (8) on its left side.

8. A multi-stage waste heat recovery and utilization device for biomass boiler flue gas according to claim 2, characterized in that, The cleaning mechanism (3) also includes a motor (311), which is fixedly connected to the top left side of the housing (5). The output end of the motor (311) is fixedly connected to a transmission shaft (312). Multiple worm gears (313) are fixedly connected at equal intervals on the outer side of the transmission shaft (312). A worm wheel (314) is fixedly connected to the middle of the outer side of each of the multiple rotating rods (32). The worm gears (313) and worm wheels (314) are meshed together.

9. A multi-stage waste heat recovery and utilization device for biomass boiler flue gas according to claim 3, characterized in that, The front end of the bidirectional threaded rod (42) passes through the U-shaped plate (41), and the outer side of the movable plate (43) is slidably connected to the inner wall of the U-shaped plate (41).

10. A multi-stage waste heat recovery and utilization device for biomass boiler flue gas according to claim 3, characterized in that, The adjustment mechanism (4) also includes a sealing gasket (49), which is sleeved on the outside of the connecting rod (44), and one side of the sealing gasket (49) is fixedly connected to the outer shell (5).

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