Biomass boiler with air preheating function

Abstract

The invention discloses an air preheating biomass boiler, belongs to the technical field of boilers, and aims to solve the problems of low combustion efficiency, insufficient flue gas waste heat utilization and particulate matter emission of a traditional biomass boiler. Function optimization is achieved through a main body structure composed of a furnace body, a charging barrel and a rotating pipe, a double-spiral-disc heat exchange assembly is arranged in the charging barrel, biomass fuel is preheated through boiler exhaust smoke waste heat, meanwhile, smoke is discharged through exhaust holes after being distributed through spiral disc gas storage cavities, and unburned particles are filtered by a biomass layer and carried to a hearth to be subjected to secondary combustion; an air inlet cavity is formed in the rotating pipe, and air is preheated through the fixed pipe and the first connecting pipe and then input into the hearth. The exhaust assembly adopts a sliding rod and sealing block matched structure, and a convex block mechanism driven by a rotating pipe drives the sealing block to periodically move, so that gas in the charging barrel is intermittently exhausted through a double-layer filter screen. According to the boiler, the heat efficiency is improved through a smoke-air two-way preheating and particulate matter secondary combustion mechanism, and the biomass preheating, air heating and emission treatment process is optimized.

Description

Technical Field

[0001] This invention belongs to the field of boiler technology and relates to an air-preheated biomass boiler. Background Technology

[0002] In the field of biomass energy utilization, biomass boilers, as highly efficient and environmentally friendly heat conversion equipment, are receiving increasing attention for their technological development. Traditional biomass boilers suffer from low energy utilization efficiency, particularly in the preheating of biomass fuel and combustion air: if the fuel is not sufficiently preheated before entering the furnace, it directly reduces combustion efficiency and heat release; while the combustion air temperature directly affects the stability of the combustion process. Furthermore, traditional boilers also face challenges in emission control, such as the need for effective purification of water vapor and harmful gases produced during combustion.

[0003] To address these issues, air-preheated biomass boiler technology has emerged in recent years. This technology utilizes the waste heat from the flue gas generated during boiler combustion to preheat the intake air, thereby improving fuel combustion efficiency and thermal energy utilization. However, the exhaust gas still carries a large amount of incompletely burned particulate matter, leading to a decrease in combustion efficiency and limiting the preheating effect of biomass fuel.

[0004] Therefore, we propose an air-preheated biomass boiler to solve the problems mentioned above. Summary of the Invention

[0005] In view of this, in order to solve the problem that the discharged flue gas also carries a large amount of unburned impurities, which reduces the combustion efficiency and makes it inconvenient to preheat the transported biomass, the present invention provides an air preheating biomass boiler.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an air-preheated biomass boiler, comprising a furnace body, a material cylinder provided on one side of the furnace body, the bottom end of the material cylinder being connected to a screw conveyor on the furnace body, and further comprising:

[0007] A rotating tube is rotatably disposed inside the material cylinder. A first spiral disk and a second spiral disk are coaxially spirally welded to the outer wall of the rotating tube. An air storage cavity is formed between the two spiral disks. Multiple exhaust holes are opened on the top of the first spiral disk.

[0008] The exhaust pipe has one end connected to the flue gas outlet of the furnace body and the other end extended into the rotating pipe and connected to the gas storage chamber, so that the flue gas is discharged through the gas storage chamber and the exhaust hole, so as to use the waste heat of the flue gas to preheat the biomass in the barrel, and at the same time filter the unburned particulate matter in the flue gas through the biomass.

[0009] An air intake pipe is installed inside the rotating pipe. One end of the pipe is connected to a blower, and the other end extends to the combustion chamber of the furnace body. An air intake chamber is formed between the outer wall of the air intake pipe and the exhaust pipe to preheat the air entering the furnace body using the waste heat of the flue gas.

[0010] The drive assembly includes a motor fixed to the barrel, a gear connected to the motor output shaft, and a gear ring welded to the outer wall of the rotating tube, wherein the gear meshes with the gear ring to drive the rotating tube to rotate.

[0011] As a further improvement to the above technical solution:

[0012] The exhaust assembly includes a guide cylinder located outside the material cylinder, a sliding rod slidably disposed within the guide cylinder, and multiple sealing blocks fixed to the sliding rod. The side wall of the material cylinder has rectangular holes corresponding to the sealing blocks. The sealing blocks are driven by the rotational power of the rotating pipe to intermittently open the rectangular holes, allowing preheated gas to be discharged through a first filter screen and a second filter screen. A fixed pipe is located at the bottom of the exhaust pipe, and the fixed pipe communicates with a gas storage chamber through multiple first connecting pipes. An annular air intake chamber is formed between the fixed pipe and the rotating pipe. A second connecting pipe is connected to the top of the air intake pipe, and the second connecting pipe is rotatably connected to the bottom end of the rotating pipe via a bearing and communicates with the air intake chamber. The drive assembly also includes a rotating disk, which is sleeved on the outer wall of the rotating pipe via a bearing. The feed pipe is welded through the rotating disc. The exhaust assembly also includes a rotating ring and a connecting rod. The rotating ring is installed inside the feed cylinder via a bearing. One end of the connecting rod is fixed to the rotating pipe, and the other end is provided with a protrusion. The protrusion rotates with the rotating pipe to push the sliding rod downward. The sliding rod is reset by a spring. One side of the guide cylinder is provided with an exhaust pipe. The bottom of the exhaust pipe is connected to a drain pipe for discharging condensate. A second filter screen is embedded in the rectangular hole. A through hole is opened on the side wall of the guide cylinder. A first filter screen is embedded in the through hole. The contact surface between the sealing block and the guide cylinder is provided with an arc-shaped sealing groove for sealing the rectangular hole when closed. The conveying path of the screw conveyor is aligned with the bottom of the second screw disc, so that the preheated biomass is conveyed to the screw conveyor via the screw disc.

[0013] The beneficial effects of this invention are as follows:

[0014] 1. The air-preheated biomass boiler disclosed in this invention is connected to the exhaust pipe via a heat exchange component. It utilizes the waste heat of flue gas to preheat the biomass in the feed cylinder, and simultaneously uses the heat exchange component to preheat the air entering the boiler body. This effectively improves energy utilization efficiency, reduces energy waste, and makes the boiler operation more energy-efficient and environmentally friendly. The heat exchange component consists of two spiral discs spirally welded to the outer wall of the rotating tube to form a gas storage chamber. The biomass is located at the top of the upper spiral disc, and the exhaust pipe is connected to the gas storage chamber, so that the flue gas is evenly distributed in the gas storage chamber, which can more evenly preheat the biomass. At the same time, it facilitates the emission and treatment of flue gas, which is conducive to the complete combustion of biomass and the stable operation of the boiler. In addition, the accumulated biomass can filter the unburned impurities in the flue gas and carry the biomass for re-combustion, which can improve the combustion efficiency.

[0015] 2. The biomass boiler with air preheating disclosed in this invention has a fixed pipe rotatably installed at the bottom of the exhaust pipe. The outer wall of the fixed pipe is connected to the air storage chamber by multiple first connecting pipes and forms an air intake chamber with the rotating pipe. The second connecting pipe welded to the top of the air intake pipe is rotatably connected to the bottom of the rotating pipe through a bearing and communicates with the air intake chamber. This ensures that air can smoothly enter the boiler body and fully contact the heat exchange components during the entry process, further improving the air preheating effect and optimizing the boiler's air intake and heat exchange process.

[0016] 3. The air preheating biomass boiler disclosed in this invention has a drive assembly that meshes with a gear fixedly sleeved at the output end of the motor and a gear ring welded to the outer wall of the rotating tube, thereby driving the rotating tube. At the same time, the feed pipe is welded through the rotating disc, and the rotating disc is rotatably sleeved on the outer wall of the rotating tube and located on the feed cylinder through a bearing. This makes the drive assembly run stably and can effectively drive the rotating tube to rotate, ensuring the normal operation of the heat exchange assembly and the exhaust assembly, and improving the overall operational stability of the boiler.

[0017] 4. The air preheating biomass boiler disclosed in this invention has an exhaust assembly that uses a guide cylinder, sliding rod, sealing blocks, and other structures to drive multiple sealing blocks to move up and down simultaneously using the rotational power of the rotating tube, thereby achieving intermittent exhaust. A second filter screen is embedded in the rectangular hole, and a first filter screen is embedded in the through hole. An exhaust chamber is formed between two adjacent sealing blocks, which can effectively exhaust the gas and water vapor in the barrel and filter the gas, reducing the emission of impurities and benefiting environmental protection. Through a rotating ring, connecting rod, protrusion, and other structures, the rotating power of the rotating tube drives the sliding rod to move downward. The spring sleeved on the outer wall of the sliding rod drives the sliding rod to move upward to reset after the protrusion rotates, realizing the reciprocating motion of the sliding rod, thereby driving the sealing blocks to perform intermittent exhaust. This makes the exhaust process closely coordinated with the rotation of the rotating tube, improving exhaust efficiency and working stability.

[0018] 5. The air preheating biomass boiler disclosed in this invention has a rectangular groove adapted to the guide cylinder on one side of the bottom end of the gas outlet pipe. It is fixed to one side of the guide cylinder by welding, and the bottom end of the gas outlet pipe is connected to a drain pipe, so that the gas discharged from the material cylinder can smoothly enter the gas outlet pipe, and at the same time, it is convenient to discharge the liquid carried in the gas, ensuring smooth gas discharge and normal operation of the equipment, and reducing the impact of liquid on the equipment.

[0019] This invention utilizes waste heat from flue gas to preheat biomass and air entering the furnace through a heat exchange component, improving energy efficiency. It also uses accumulated biomass to filter flue gas. The drive component stably drives the rotating tube to rotate, ensuring uniform heat exchange. The exhaust component, in conjunction with the drive component, enables intermittent exhaust, effectively discharging gas and water vapor. Furthermore, the exhaust process filters the gas, and the design of the exhaust pipe and liquid drain pipe optimizes gas and liquid discharge.

[0020] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0022] Figure 1 This is a three-dimensional structural schematic diagram of an air-preheated biomass boiler according to the present invention.

[0023] Figure 2 This is a schematic diagram of the exhaust pipe and feed cylinder installation structure of an air-preheated biomass boiler according to the present invention.

[0024] Figure 3 This is a schematic diagram showing the exploded structure of the exhaust pipe and feed cylinder of an air-preheated biomass boiler according to the present invention.

[0025] Figure 4 This is a schematic cross-sectional view of the spiral disk structure of a biomass boiler with air preheating according to the present invention.

[0026] Figure 5 This is a schematic diagram of the installation structure of the sealing block and guide cylinder of an air preheating biomass boiler according to the present invention;

[0027] Figure 6 This is a schematic diagram of the air outlet pipe structure of a biomass boiler with air preheating according to the present invention.

[0028] Reference numerals: 1. Furnace body; 2. Support frame; 3. Screw conveyor; 4. Material cylinder; 5. Feed pipe; 6. Blower; 7. Air inlet pipe; 8. Exhaust pipe; 9. Air outlet pipe; 10. Rotating pipe; 11. Air inlet chamber; 12. Motor; 13. Rotating disc; 14. Rotating ring; 15. Guide cylinder; 16. Sliding rod; 17. Spring; 18. Support base; 19. Toothed ring; 20. Rectangular hole; 21. Limiting block; 22. Sealing block; 23. Through hole; 24. First filter screen; 25. Screw disc; 26. Air storage chamber; 27. Exhaust hole; 28. Second filter screen; 29. ​​First connecting pipe; 30. Second connecting pipe; 31. Connecting rod; 32. Protrusion; 33. Fixing pipe; 34. Arc groove; 35. Exhaust chamber; 36. Rectangular groove; 37. Drain pipe. Detailed Implementation

[0029] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0030] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0031] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0032] Example 1

[0033] like Figures 1-6As shown, a boiler includes a furnace body 1. A support frame 2 is installed on one side of the furnace body 1, and a feed cylinder 4 is mounted on the support frame 2. The top of the feed cylinder 4 has a feed pipe 5 for use with a conveyor, and the bottom end is connected to a screw conveyor 3 on the furnace body 1. A rotating tube 10 is rotatably installed inside the feed cylinder 4. A heat exchange component is installed inside the rotating tube 10 and connected to an exhaust pipe 8 on the furnace body 1. This component is used to preheat the biomass inside the feed cylinder 4 using waste heat from the flue gas. A drive component is also provided on the feed cylinder 4 to drive the rotating tube 10 to rotate. An air inlet pipe 7 is also provided inside the rotating tube 10. The other end of the air inlet pipe 7 is connected to a blower 6 on the furnace body 1 to preheat the air entering the furnace body 1 using the heat exchange component. An exhaust component is provided on one side of the feed cylinder 4 to discharge the gas and water vapor inside the feed cylinder 4.

[0034] The heat exchange assembly consists of two spiral discs 25 spirally welded to the outer wall of the rotating tube 10, forming a gas storage chamber 26 between the two spiral discs 25. Multiple exhaust holes 27 are opened on the top of the upper spiral disc 25. Biomass is placed on the top of the upper spiral disc 25, and the bottom end of the exhaust pipe 8 is connected to the gas storage chamber 26. A fixed pipe 33 is rotatably mounted inside the rotating tube 10 at the bottom of the exhaust pipe 8. Multiple first connecting pipes 29 penetrate the outer wall of the fixed pipe 33, and the other end of each first connecting pipe 29 penetrates the outer wall of the rotating tube 10 and is connected to the gas storage chamber 26. The bottom end of the fixed pipe 33 is sealed, and an air inlet chamber 11 is formed between it and the rotating tube 10. A second connecting pipe 30 is welded to the top of the air inlet pipe 7. The top end of the second connecting pipe 30 is rotatably connected to the bottom end of the rotating tube 10 via a bearing and is connected to the air inlet chamber 11.

[0035] The flue gas enters the fixed pipe 33 from the exhaust pipe 8, enters the gas storage chamber 26 through the first connecting pipe 29, and exits from the exhaust port 27. During the exit process, the biomass on the upper spiral disc 25 is preheated, and the biomass also filters out unburned impurities in the flue gas, causing the impurities to adhere to the biomass. This allows the biomass to carry unburned impurities into the furnace body 1 during transportation, improving the combustion efficiency of the biomass during re-combustion. Simultaneously, air enters the air intake chamber 11 from the second connecting pipe 30 and flows downwards. During this flow, it exchanges heat with the fixed pipe 33 and the first connecting pipe 29, achieving preheating, before entering the air intake pipe 7 through the second connecting pipe 30 and then entering the furnace body 1 through the blower 6, improving combustion efficiency.

[0036] The drive assembly includes a rotating disk 13 that is rotatably mounted on the outer wall of the rotating tube 10 and located on the material cylinder 4 via a bearing. The feed pipe 5 is welded through the rotating disk 13. A support base 18 is welded to the top of the rotating disk 13. A motor 12 is fixedly mounted on the support base 18 by bolts. A gear ring 19 is welded to the outer wall of the rotating tube 10. A gear that meshes with the gear ring 19 is fixedly mounted on the output end of the motor 12.

[0037] The motor 12 is started, and the rotating tube 10 is driven to rotate through the meshing of the gear and the gear ring 19, thereby realizing the rotation of the heat exchange component in the barrel 4, so that the biomass is heated more evenly. At the same time, the biomass can be conveyed downward through the spiral disc 25 without affecting the external conveyor conveying biomass into the barrel 4.

[0038] The exhaust assembly includes a guide cylinder 15, on which a sliding rod 16 is slidably mounted. Multiple sealing blocks 22 are fixedly sleeved on the outer wall of the sliding rod 16. Both the sealing blocks 22 and the guide cylinder 15 have arc-shaped grooves 34 on one side that are adapted to the outer side of the material cylinder 4 so as to fit against the outer wall of the material cylinder 4. The guide cylinder 15 is welded to the outer wall of the material cylinder 4. Multiple rectangular holes 20 are opened on the outer side of the material cylinder 4. A second filter screen 28 is embedded in the rectangular holes 20. The sealing blocks 22 are located on one side of the rectangular holes 20 for sealing. A through hole 23 corresponding to the rectangular holes 20 is also opened on the outer side of the guide cylinder 15. A first filter screen 24 is embedded in the through hole 23. An exhaust chamber 35 is formed between two adjacent sealing blocks 22. When it is necessary to exhaust the flue gas in the material cylinder 4, it is only necessary to push the sliding rod 16 downward with external force to drive the sealing blocks 22 to be misaligned with the rectangular holes 20, so that the exhaust chamber 35 corresponds to the rectangular holes 20 and the through holes 23. The material cylinder 4 is provided with a driving component connected to the rotating tube 10.

[0039] This application can be used in the field of boilers, or in other fields applicable to this application.

[0040] Example 2

[0041] refer to Figures 1-6An improvement based on Embodiment 1: An air-preheated biomass boiler, applied in the boiler field, includes a driving component comprising a rotating ring 14 rotatably mounted between a rotating disk 13 and a feed cylinder 4 via a bearing. A connecting rod 31 is welded through the outer side of the rotating ring 14. One end of the connecting rod 31 is welded to a rotating tube 10, and the other end is welded to a protrusion 32 that cooperates with a sliding rod 16. When the rotating tube 10 rotates, the connecting rod 31 drives the rotating ring 14 to rotate, which in turn drives the protrusion 32 to rotate around the axis of the rotating tube 10. When the protrusion 32 abuts against the sliding rod 16, it drives the sliding rod 16 to move downward. A spring 17 is sleeved on the outer wall of the sliding rod 16 above a guide cylinder 15. The two ends of the spring 17 are fixedly connected to the top of the guide cylinder 15 and the top outer wall of the sliding rod 16, respectively. When the protrusion 32 rotates away from the sliding rod 16, the spring 17 drives the sliding rod 16 to move upward to reset, and the sealing block 22 re-seals the rectangular hole 20, achieving intermittent exhaust. Limiting blocks 21 for limiting are welded to both ends of the sliding rod 16. An exhaust pipe 9 is provided on one side of the guide cylinder 15. A rectangular groove 36 adapted to the guide cylinder 15 is opened on one side of the bottom end of the exhaust pipe 9. The exhaust pipe 9 is fixedly installed on one side of the guide cylinder 15 by welding. The bottom end of the exhaust pipe 9 is connected to a drain pipe 37, so that the water vapor in the exhaust gas condenses into liquid in the exhaust pipe 9 and is discharged through the drain pipe 37. The contact surface of the protrusion 32 can be designed as an involute curved surface to make the lifting and lowering action of the sliding rod 16 smoother and reduce impact.

[0042] The cross-section of the rotating tube 10 can be designed in the following shapes to improve the stirring and heat exchange effect: 1. Polygonal cross-section: The rotating tube 10 adopts a hexagonal or octagonal cross-section. Its edges can generate a directional pushing force on the biomass when rotating, avoiding the biomass from adhering to the inner wall of the barrel 4, and at the same time enhancing the turbulent heat exchange between the tube wall and the air; 2. Outer wall protrusion structure: The outer surface of the rotating tube 10 is welded with hemispherical protrusions arranged in a spiral. The protrusions can break up the biomass layer, increase the contact frequency between the flue gas and the material, and at the same time improve the heat exchange efficiency between the rotating tube 10 and the air in the air inlet chamber 11.

[0043] In operation, the biomass is transported by a conveyor, falling through the feed pipe 5 into the feed cylinder 4 and onto the upper spiral disc 25. Simultaneously, the motor 12 is started. During startup, the meshing gears and gear ring 19 drive the rotating pipe 10 to rotate. The rotation of the rotating pipe 10 drives the two spiral discs 25 to rotate, causing the biomass on the spiral discs 25 to move downwards until it reaches the screw conveyor 3. The screw conveyor 3 is then started to transport the biomass into the furnace body 1, and the igniter inside the furnace body 1 is activated. When biomass is ignited, the heat from the combustion can be used to heat the water inside the furnace body 1. The resulting flue gas enters the exhaust pipe 8, then the fixed pipe 33, and then the gas storage chamber 26 through the first connecting pipe 29. It floats upward through the exhaust hole 27 on the upper spiral disc 25, which can heat the biomass on the spiral disc 25. At the same time, the unburned impurities in the gas are filtered by the biomass. During the process of transporting the biomass into the furnace body 1, it can carry the unburned impurities back into the furnace body 1 for re-combustion.

[0044] At the same time, the blower 6 is started to deliver air into the furnace body 1, while the external air can first enter the air intake chamber 11. During the process of entering the air intake chamber 11, the residual heat of the fixed pipe 33 and the first connecting pipe 29 can be used to heat the external air, so that the heated air can enter the furnace body 1 and improve the combustion efficiency.

[0045] During the rotation of the rotating tube 10, the connecting rod 31 and the rotating ring 14 can drive the protrusion 32 to rotate around the material cylinder 4. When the protrusion 32 contacts the upper limiting block 21, it can drive it to move downward. The downward movement of the limiting block 21 can cause the sealing block 22 to move downward, so that the exhaust chamber 35 corresponds to the rectangular hole 20 and the through hole 23. At this time, the gas between the two adjacent spiral discs 25 can be discharged into the exhaust pipe 9 through the rectangular hole 20, the exhaust chamber 35 and the through hole 23, and finally discharged through the exhaust pipe 9. The water vapor in the hot gas can flow downward through the inner wall of the exhaust pipe 9 and the outer wall of the guide cylinder 15, and finally be discharged through the drain pipe 37. When the protrusion 32 moves away from the limiting block 21, the sliding rod 16 can move upward under the action of the spring 17, and drive the sealing block 22 to move upward, so that it seals the second filter screen 28.

[0046] However, as is well known to those skilled in the art, the working principles and wiring methods of the furnace body 1, screw conveyor 3, blower 6 and motor 12 are commonplace and are all conventional methods or common knowledge. They will not be described in detail here. Those skilled in the art can make any selections according to their needs or convenience.

[0047] Finally, it should be noted that 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An air-preheated biomass boiler, comprising a boiler body (1), wherein a feed cylinder (4) is provided on one side of the boiler body (1), and the bottom end of the feed cylinder (4) is connected to a screw conveyor (3) on the boiler body (1), characterized in that, Also includes: A rotating tube (10) is rotatably disposed inside the material cylinder (4). The outer wall of the rotating tube (10) is coaxially spirally welded with a first spiral disk (25) and a second spiral disk (25). An air storage cavity (26) is formed between the two spiral disks (25). Multiple exhaust holes (27) are opened on the top of the first spiral disk (25). The exhaust pipe (8) has one end connected to the flue gas outlet of the furnace body (1) and the other end extended into the rotating pipe (10) and connected to the gas storage chamber (26), so that the flue gas is discharged through the gas storage chamber (26) and the exhaust hole (27) to utilize the residual heat of the flue gas to preheat the biomass in the feed cylinder (4), and at the same time filter the incompletely burned particulate matter in the flue gas through the biomass. An air inlet pipe (7) is installed inside the rotating pipe (10). One end of the pipe is connected to a blower (6), and the other end extends to the combustion chamber of the furnace body (1). An air inlet chamber (11) is formed between the outer wall of the air inlet pipe (7) and the exhaust pipe (8) to preheat the air entering the furnace body (1) using the waste heat of the flue gas. The drive assembly includes a motor (12) fixed to the barrel (4), a gear connected to the output shaft of the motor, and a gear ring (19) welded to the outer wall of the rotating tube (10), wherein the gear meshes with the gear ring (19) to drive the rotating tube (10) to rotate.

2. The biomass boiler according to claim 1, characterized in that, The exhaust assembly includes a guide cylinder (15) located outside the material cylinder (4), a sliding rod (16) slidably disposed inside the guide cylinder (15), and a plurality of sealing blocks (22) fixed on the sliding rod (16). The side wall of the material cylinder (4) is provided with a rectangular hole (20) corresponding to the sealing block (22). The sealing block (22) is driven by the rotational power of the rotating tube (10) to intermittently open the rectangular hole (20), so that the gas generated by preheating is discharged through the first filter screen (24) and the second filter screen (28).

3. The biomass boiler according to claim 2, characterized in that, The bottom of the exhaust pipe (8) is provided with a fixed pipe (33), which is connected to the air storage chamber (26) through multiple first connecting pipes (29), and an annular air intake chamber (11) is formed between the fixed pipe (33) and the rotating pipe (10).

4. The biomass boiler according to claim 3, characterized in that, The top end of the air intake pipe (7) is connected to a second connecting pipe (30), which is rotatably connected to the bottom end of the rotating pipe (10) via a bearing and communicates with the air intake chamber (11).

5. The biomass boiler according to claim 1, characterized in that, The drive assembly also includes a rotating disk (13), which is sleeved on the outer wall of the rotating tube (10) via a bearing, and the feed pipe (5) of the material cylinder (4) is welded through to the rotating disk (13).

6. The biomass boiler according to claim 2, characterized in that, The exhaust assembly also includes a rotating ring (14) and a connecting rod (31). The rotating ring (14) is installed in the material cylinder (4) by a bearing. One end of the connecting rod (31) is fixed to the rotating tube (10), and the other end is provided with a protrusion (32). The protrusion (32) rotates with the rotating tube (10) to push the sliding rod (16) to move downward. The sliding rod (16) is reset by a spring (17).

7. The biomass boiler according to claim 6, characterized in that, The guide tube (15) is provided with an air outlet pipe (9) on one side, and the bottom of the air outlet pipe (9) is connected to the drain pipe (37) for discharging condensed liquid.

8. The biomass boiler according to claim 7, characterized in that, The rectangular hole (20) is fitted with a second filter screen (28), and the side wall of the guide cylinder (15) is provided with a through hole (23), in which a first filter screen (24) is fitted.

9. The biomass boiler according to claim 8, characterized in that, The contact surface between the sealing block (22) and the guide cylinder (15) is provided with an arc-shaped sealing groove (34) for sealing the rectangular hole (20) when closed.

10. The biomass boiler according to any one of claims 1-8, characterized in that, The conveying path of the screw conveyor (3) is aligned with the bottom of the second screw disc (25), so that the preheated biomass is conveyed to the screw conveyor (3) via the screw disc (25).

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