Biomass particle hot blast stove

Abstract

The biomass particle hot blast stove comprises a stove body, a feeding assembly, a combustion assembly, a heat exchange assembly and a smoke exhaust assembly. The combustion assembly is arranged in the furnace body, a combustion chamber of the combustion assembly is sequentially divided into a drying pyrolysis area, a main combustion area and a burnout area in the conveying direction of biomass particles, and ordered partitioned combustion of preheating, sufficient combustion and complete burnout of fuel is achieved; the heat exchange assembly comprises a first heat exchange set arranged above the combustion assembly and a second heat exchange set arranged in the circumferential direction of the combustion assembly, and a three-dimensional and multi-layer waste heat recovery structure is formed. The combustion efficiency and the burn-off rate of the biomass particles are obviously improved; through the first heat exchange set and the second heat exchange set, efficient and sufficient recovery of combustion waste heat is achieved, and the overall heat efficiency and the energy utilization rate of the hot blast stove are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of hot blast stoves, and more particularly to a biomass pellet hot blast stove. Background Technology

[0002] Biomass pellet hot air furnaces are thermal energy devices that use shaped biomass pellets as fuel to provide clean hot air for industrial production, and are widely used in agricultural drying, wood processing, and other fields. Existing biomass pellet hot air furnaces typically have a relatively simple combustion chamber structure, resulting in incomplete and disordered combustion of fuel within the chamber. This leads to low combustion efficiency, low burnout rate, and the inefficient and insufficient recovery and utilization of the heat generated during combustion, resulting in significant waste heat loss and affecting the overall thermal efficiency and energy utilization rate of the hot air furnace. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a biomass pellet hot air furnace.

[0004] To achieve the above-mentioned technical objectives, the technical solution adopted by this invention is as follows: A biomass pellet hot air furnace includes a furnace body, a feeding assembly, a combustion assembly, a heat exchange assembly, and a flue gas exhaust assembly. The feeding assembly is located on one side of the furnace body and is used to transport biomass pellets. The combustion assembly is located inside the furnace body and includes a combustion chamber, which is divided into a drying pyrolysis zone, a main combustion zone, and a burnout zone along the conveying direction of the biomass pellets. The combustion chamber is connected to the feeding assembly. The heat exchange assembly includes a first heat exchange group and a second heat exchange group. The first heat exchange group is located above the combustion assembly, and the second heat exchange group is located circumferentially around the combustion assembly. The first and second heat exchange groups are used to recover waste heat from the combustion chamber. The flue gas exhaust assembly is located on the other side of the furnace body and is connected to the combustion assembly. The flue gas exhaust assembly is used to exhaust the flue gas from the combustion chamber.

[0005] In some embodiments, the first heat exchange group includes a first heat-conducting main pipe, a plurality of first heat-conducting branch pipes, and a first heat-conducting ring wall. The first heat-conducting main pipe is disposed above the combustion chamber. The plurality of first heat-conducting branch pipes are distributed in a first preset manner around the first heat-conducting main pipe, and the first heat-conducting branch pipes are connected to the first heat-conducting main pipe. The first heat-conducting ring wall is sleeved on the outside of the combustion chamber, and a first heat-conducting cavity is formed between the inner side of the first heat-conducting ring wall and the outer side of the combustion chamber. The first heat-conducting branch pipes are connected to the first heat-conducting cavity.

[0006] In some embodiments, the upper end of the first heat conduction pipe is provided with a first opening, and the first opening is disposed facing upwards of the combustion chamber, the lower end of the first heat conduction pipe is closed, and the diameter of the first heat conduction pipe is smaller than that of the combustion chamber.

[0007] In some embodiments, the first heat exchange group further includes a plurality of second heat-conducting branch pipes, a second heat-conducting ring wall, and a third heat-conducting ring wall. The plurality of second heat-conducting branch pipes are distributed in a second predetermined manner along the circumference of the first heat-conducting main pipe, and the plurality of second heat-conducting branch pipes are set higher than the first heat-conducting branch pipe. The second heat-conducting ring wall is sleeved on the outside of the first heat-conducting ring wall. The third heat-conducting ring wall is sleeved on the outside of the second heat-conducting ring wall, and a second heat-conducting cavity is formed between the outer side of the second heat-conducting ring wall and the inner side of the third heat-conducting ring wall. The second heat-conducting branch pipes are connected to the second heat-conducting cavity.

[0008] In some embodiments, the second heat exchange group includes a second heat-conducting main pipe and a plurality of third heat-conducting branch pipes. The second heat-conducting main pipe is disposed in the combustion chamber and inside the first heat-conducting main pipe. The second heat-conducting main pipe is in communication with the combustion chamber but is not directly in communication with the first heat-conducting main pipe. The plurality of third heat-conducting branch pipes are distributed in a third predetermined manner around the second heat-conducting main pipe. A third heat-conducting cavity is provided between the furnace body and the outer side of the third heat-conducting ring wall, and the third heat-conducting cavity is in communication with the third heat-conducting branch pipes.

[0009] In some embodiments, the second heat exchange group further includes an annular baffle and a branch pipe. The annular baffle is disposed in the third heat conduction cavity to divide the third heat conduction cavity into a confluence cavity and a branch cavity. The confluence cavity is disposed in the upper part of the furnace body and communicates with the third heat conduction branch pipe. The branch pipe communicates with the confluence cavity and is distributed circumferentially along the third heat conduction ring wall and is placed in the branch cavity.

[0010] In some embodiments, the second heat exchange group further includes spiral fins disposed on the outside of each branch pipe, the spiral fins being used to increase the heat conduction area.

[0011] In some embodiments, the smoke exhaust assembly includes a first smoke exhaust base plate, a second smoke exhaust base plate, a first smoke exhaust side plate, a first ash removal cover plate, a smoke exhaust fan, a flue, a first smoke exhaust top plate, and a second ash removal cover plate; the first smoke exhaust base plate is connected to a first heat conduction cavity, a second heat conduction cavity, and a branch pipe respectively; the second smoke exhaust base plate is disposed below the first smoke exhaust base plate; the first smoke exhaust side plate is disposed between the first smoke exhaust base plate and the second smoke exhaust base plate to form a first smoke exhaust cavity, and a first ash removal port is provided on the first smoke exhaust side plate; a first ash removal cover plate covers the first ash removal port; the smoke exhaust fan is disposed on one side of the furnace body and is connected to the first smoke exhaust cavity; the flue is connected to the output end of the smoke exhaust fan; the first smoke exhaust top plate is disposed above the confluence cavity and forms a second smoke exhaust cavity with an annular partition, and a second ash removal port is provided on the first smoke exhaust top plate; a second ash removal cover plate covers the second ash removal port.

[0012] In some embodiments, the combustion assembly further includes a first combustion tube, a combustion grid, a first feed pipe, and a first discharge pipe. The first combustion tube is disposed below the combustion chamber and has a heating wire inside. The combustion grid is embedded in the combustion chamber and is used to receive biomass pellets. The area where the combustion grid is located is the main combustion zone. The first feed pipe is connected to the combustion chamber and is located in the pyrolysis drying zone. The first discharge pipe is connected to the combustion chamber and is disposed opposite to the first feed pipe. The area where the first discharge pipe is located is the burnout zone.

[0013] In some embodiments, the feeding assembly includes a second feeding pipe, a feeding hopper, a spiral feeding blade, a drive unit, an air guide pipe, and a fan. One end of the second feeding pipe is connected to the first feeding pipe; the feeding hopper is disposed at the other end of the second feeding pipe; the spiral feeding blade is disposed inside the second feeding pipe; the drive unit is drivenly connected to the spiral feeding blade; the air guide pipe is connected to the connection between the second feeding pipe and the first feeding pipe; the fan is connected to the other end of the air guide pipe and is disposed on the outside of the furnace body.

[0014] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art: Unlike existing technologies, the biomass pellet hot air furnace in the above technical solution includes a furnace body, a feeding assembly, a combustion assembly, a heat exchange assembly, and a flue gas assembly. The combustion assembly is located inside the furnace body, and its combustion chamber is sequentially divided into a drying pyrolysis zone, a main combustion zone, and a burnout zone along the conveying direction of the biomass pellets, achieving orderly zoned combustion of fuel preheating, complete combustion, and total burnout. Simultaneously, the heat exchange assembly includes a first heat exchange group positioned above the combustion assembly and a second heat exchange group positioned circumferentially around the combustion assembly, forming a three-dimensional, multi-layered waste heat recovery structure. This technical solution scientifically partitions the fuel combustion process spatially, extending the flue gas flow and residence time, ensuring complete combustion and burnout of the fuel, thereby improving combustion efficiency from the source. Furthermore, through the synergistic effect of the first and second heat exchange groups, heat dissipated above and circumferentially from the combustion chamber can be captured and recovered comprehensively and efficiently, significantly reducing flue gas heat loss. This technical solution significantly improves the combustion efficiency and burnout rate of biomass pellets through a zoned combustion design; and achieves efficient and full recovery of combustion waste heat through a three-dimensional arrangement of the first and second heat exchange groups, greatly improving the overall thermal efficiency and energy utilization rate of the hot blast stove. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a first schematic diagram of the biomass pellet hot air furnace described in the specific implementation method; Figure 2 This is a second schematic diagram of the biomass pellet hot air furnace described in the specific embodiment; Figure 3 This is a third schematic diagram of the biomass pellet hot air furnace described in the specific implementation method; Figure 4 This is the fourth schematic diagram of the biomass pellet hot air furnace described in the specific implementation method; Figure 5 This is the fifth schematic diagram of the biomass pellet hot air furnace described in the specific implementation method; Figure 6 This is the sixth schematic diagram of the biomass pellet hot air furnace described in the specific implementation method; Figure 7 This is the seventh schematic diagram of the biomass pellet hot air furnace described in the specific implementation method; Figure 8 This is the eighth schematic diagram of the biomass pellet hot air furnace described in the specific implementation method; Figure 9 This is the ninth schematic diagram of the biomass pellet hot air furnace described in the specific implementation method.

[0017] Figure label: 1. Furnace body; 2. Feeding assembly; 21. Second feed pipe; 22. Feed hopper; 23. Spiral feed blades; 24. Drive unit; 25. Air duct; 26. Fan; 3. Combustion assembly; 31. Combustion chamber; 32. First combustion tube; 33. Combustion grille; 34. First conveying pipe; 35. First discharge pipe; 4. First heat exchange group; 41. Primary heat conduction pipe; 411. First opening; 42. First heat-conducting branch pipe; 43. First heat-conducting ring wall; 44. Second heat-conducting branch pipe; 45. Second heat-conducting ring wall; 46. ​​Third heat-conducting ring wall; 47. First heat-conducting cavity; 48. Second heat-conducting cavity; 5. Second heat exchange group; 51. Second heat conduction main pipe; 52. Third heat-conducting branch pipe; 53. Third heat-conducting cavity; 531. Manifold; 532. Flow divider; 54. Annular partition; 55. Branch pipe; 56. Spiral fins; 6. Smoke exhaust system; 61. First smoke exhaust base plate; 62. Second smoke exhaust bottom plate; 63. First smoke exhaust side panel; 64. First dust removal cover plate; 65. Smoke exhaust fan; 66. Smoke pipe; 67. First row of smoke exhaust top plate; 68. Second dust removal cover plate; 69. First smoke exhaust chamber. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the invention. Similarly, the following embodiments are only some, not all, embodiments of the present invention, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figures 1 to 9 This embodiment provides a biomass pellet hot air furnace, including a furnace body 1, a feeding assembly 2, a combustion assembly 3, a heat exchange assembly, and a flue gas exhaust assembly 6. The feeding assembly 2 is located on one side of the furnace body 1 and is used to transport biomass pellets. The combustion assembly 3 is located inside the furnace body 1 and includes a combustion chamber 31. The combustion chamber 31 is divided into a drying pyrolysis zone, a main combustion zone, and a burnout zone along the conveying direction of the biomass pellets. The combustion chamber 31 is connected to the feeding assembly 2. The heat exchange assembly includes a first heat exchange group 4 and a second heat exchange group 5. The first heat exchange group 4 is located above the combustion assembly 3, and the second heat exchange group 5 is located circumferentially on the combustion assembly 3. The first heat exchange group 4 and the second heat exchange group 5 are used to recover waste heat from the combustion chamber 31. The flue gas exhaust assembly 6 is located on the other side of the furnace body 1 and is connected to the combustion assembly 3. The flue gas exhaust assembly 6 is used to exhaust the flue gas from the combustion in the combustion chamber 31.

[0020] In this embodiment, the furnace body 1 refers to the shell that constitutes the main external structure of the hot blast stove, used to house and protect the internal functional components. Its material is preferably steel plate, and an external insulation layer can be applied to reduce heat loss. The feeding assembly 2 is located on one side of the furnace body 1 and is used to continuously and stably feed biomass pellets into the furnace. It can be a screw feeder, a pneumatic conveying device, or a combination thereof to ensure uniform fuel supply.

[0021] The combustion assembly 3, located within the furnace body 1, is the core area for fuel energy conversion and includes a combustion chamber 31. The combustion chamber 31 refers to the space where the fuel undergoes a combustion reaction. In this embodiment, it is sequentially divided into a drying pyrolysis zone, a main combustion zone, and a burnout zone along the conveying direction of the biomass pellets. The drying pyrolysis zone receives and preheats the fuel, causing its moisture to evaporate and releasing volatiles. The main combustion zone is the area with the most intense combustion reaction, used to achieve complete combustion of volatiles and some fixed carbon. The burnout zone ensures the complete combustion of remaining fixed carbon, thereby improving fuel utilization. This zoned structure creates a temperature gradient, which is beneficial for the orderly and complete combustion process. The combustion chamber 31 is connected to the feeding assembly 2 to receive fuel.

[0022] The heat exchange assembly includes a first heat exchange group 4 and a second heat exchange group 5, used to efficiently recover the heat generated by combustion to heat clean air. The first heat exchange group 4 is located above the combustion assembly 3, used to directly capture and absorb the heat radiated upwards and transferred by convection from the flame and high-temperature flue gas. The second heat exchange group 5 is located circumferentially around the combustion assembly 3, that is, around the periphery of the combustion chamber 31, used to absorb the heat conducted through the wall of the combustion chamber 31 and the convective heat from the circumferential flue gas. The first heat exchange group 4 and the second heat exchange group 5 together form a three-dimensional, multi-layered waste heat recovery network. The flue gas exhaust assembly 6 is located on the other side of the furnace body 1 and communicates with the combustion assembly 3, used to safely and smoothly exhaust the low-temperature flue gas generated after combustion in the combustion chamber 31 outside the furnace.

[0023] In operation, biomass pellets are continuously fed into the drying and pyrolysis zone of combustion chamber 31 via feed assembly 2, where they are preheated and begin pyrolysis. The fuel then enters the main combustion zone, where it burns vigorously under a sufficient oxygen supply, releasing a large amount of heat. Finally, unburned residue enters the burnout zone for final combustion. During this process, the high-temperature heat generated by combustion is directly absorbed by the first heat exchange group 4 above, and also conducted through the walls of combustion chamber 31 to the circumferential second heat exchange group 5. Clean air to be heated is efficiently heated as it flows through the first and second heat exchange groups 4 and 5, forming high-temperature hot air for downstream use. The temperature of the flue gas after combustion is significantly reduced due to the full recovery of heat, and it is finally discharged via exhaust assembly 6. The entire system, through the synergy of combustion zoning and the three-dimensional heat exchange layout, achieves a complete energy-efficient utilization chain from efficient fuel combustion to full recovery of waste heat.

[0024] This embodiment divides the combustion chamber 31 into a drying pyrolysis zone, a main combustion zone, and a burnout zone along the fuel conveying direction, achieving an orderly zoned combustion process of fuel preheating, complete combustion, and total burnout. This effectively extends the fuel residence time in the furnace and optimizes the temperature field distribution, thereby fundamentally improving combustion efficiency and burnout rate. Furthermore, by placing the first heat exchange group 4 above the combustion assembly 3 to directly capture high-temperature radiation and convective heat, and simultaneously surrounding the combustion assembly 3 with the second heat exchange group 5 to absorb heat conducted from the wall surface and waste heat from the circumferential flue gas, a three-dimensional, all-round waste heat recovery system is constructed. When clean air flows through this waste heat recovery system, it is synergistically and efficiently heated by the first heat exchange group 4 and the second heat exchange group 5. This maximizes the capture and utilization of heat generated by combustion, significantly reducing exhaust gas temperature and heat loss. Therefore, this biomass pellet hot air furnace combines the dual advantages of complete combustion and high heat exchange efficiency, significantly improving overall thermal efficiency. Simultaneously, due to complete combustion, it also helps reduce the generation of incomplete combustion products, resulting in significant energy-saving and environmental benefits. Preferably, by adopting appropriate refractory materials and selecting appropriate heat exchangers, the long-term stable operating life of the equipment under high temperature and corrosive atmosphere is further guaranteed.

[0025] Please see Figures 1 to 6 In some embodiments, the first heat exchange group 4 includes a first heat conduction main pipe 41, a plurality of first heat conduction branch pipes 42, and a first heat conduction ring wall 43. The first heat conduction main pipe 41 is disposed above the combustion chamber 31. The plurality of first heat conduction branch pipes 42 are distributed in a first preset manner around the first heat conduction main pipe 41, and the first heat conduction branch pipes 42 are connected to the first heat conduction main pipe 41. The first heat conduction ring wall 43 is sleeved on the outside of the combustion chamber 31, and a first heat conduction cavity 47 is formed between the inner side of the first heat conduction ring wall 43 and the outer side of the combustion chamber 31. The first heat conduction branch pipes 42 are connected to the first heat conduction cavity 47.

[0026] In this embodiment, the first heat-conducting main pipe 41 is located directly above the combustion chamber 31, serving as the main flow channel of the heat exchange group for collecting or distributing the heat exchange medium (such as air or water). Multiple first heat-conducting branch pipes 42 are distributed circumferentially around the first heat-conducting main pipe 41 in a first predetermined manner (e.g., radial, annular array, etc.) and communicate with the internal flow channel of the first heat-conducting main pipe 41, guiding the heat exchange medium from the main pipe to a wider heat exchange area. A first heat-conducting annular wall 43 is fitted around the outside of the combustion chamber 31, with a certain gap between its inner wall and the outer wall of the combustion chamber 31, thus forming a first heat-conducting cavity 47 surrounding the combustion chamber 31. The ends of the first heat-conducting branch pipes 42 communicate with this first heat-conducting cavity 47, allowing the heat exchange medium to flow from the first heat-conducting main pipe 41 into the first heat-conducting cavity 47 via the first heat-conducting branch pipes 42, or flow in the opposite direction.

[0027] In this embodiment, the first heat exchange group 4 achieves three-dimensional, multi-path heat capture through the aforementioned structure. Specifically, the first heat-conducting main pipe 41 and branch pipes located above the combustion chamber 31 can directly and efficiently absorb the intense heat radiated upwards and transferred by the flame and high-temperature flue gas. Simultaneously, the first heat-conducting ring wall 43, coaxially fitted with the combustion chamber 31, and the first heat-conducting cavity 47 it forms constitute a circumferential heat exchange jacket enclosing the combustion chamber 31. This jacket effectively absorbs the heat conducted through the refractory wall of the combustion chamber 31 and performs secondary recovery of the waste heat from the flue gas flowing around the jacket. When the heat exchange medium (such as cold air) flows through the system, it is rapidly heated in the area of ​​the first heat-conducting main pipe 41 and the first heat-conducting branch pipe 42 at the top, and then enters the circumferential first heat-conducting cavity 47, flowing along the outer wall of the combustion chamber 31 to further absorb heat conducted through the wall. This achieves a stepped, all-around recovery of heat above and around the combustion chamber 31, greatly improving the efficiency and uniformity of waste heat recovery.

[0028] Please see Figures 4 to 6 In some embodiments, the upper end of the first heat conduction pipe 41 is provided with a first opening 411, and the first opening 411 is disposed facing the upper part of the combustion chamber 31. The lower end of the first heat conduction pipe 41 is closed, and the diameter of the first heat conduction pipe 41 is smaller than that of the combustion chamber 31.

[0029] In this embodiment, the structural design of the first heat conduction pipe 41 further optimizes the heat exchange function and airflow organization. Specifically, the upper end of the first heat conduction pipe 41 is provided with a first opening 411, and this first opening 411 is oriented directly towards the space above the combustion chamber 31. Meanwhile, the lower end of the first heat conduction pipe 41 is closed. In addition, the diameter of the first heat conduction pipe 41 is designed to be smaller than the diameter of the combustion chamber 31.

[0030] The upper end of the first heat-conducting main pipe 41 is set to open towards the combustion chamber 31, while the lower end is closed. This essentially defines a cylindrical or tubular structure with a "closed bottom and open top," which facilitates the formation of a specific airflow path: when the heat exchange medium (such as air) rises after combustion in the combustion chamber 31, due to the closed lower end, the heat exchange medium will mainly flow upwards, eventually entering the first heat-conducting branch pipe 42 and the second heat-conducting branch pipe 44 through the first opening 411 at the top. This allows the heat exchange medium to fully absorb the heat captured by the wall of the first heat-conducting main pipe 41 from the high-temperature area above the combustion chamber 31. More importantly, the setting of the first opening 411 at the top directly facing the high-temperature flue gas area above the combustion chamber 31 allows the pre-heated medium flowing out of the first opening 411 to directly and fully mix and undergo secondary heat exchange with the hottest flame and rising flue gas, optimizing the temperature field inside the furnace. Secondly, designing the diameter of the first heat transfer tube 41 to be smaller than that of the combustion chamber 31 can prevent it from occupying too much space above the combustion chamber 31, thereby ensuring that the combustion flame has sufficient expansion space and flue gas flow cross section, preventing the stability and completeness of combustion from being affected by the excessive size of the heat exchanger structure, and achieving a balance between efficient heat exchange and good combustion conditions.

[0031] Please see Figures 1 to 6 In some embodiments, the first heat exchange group 4 further includes a plurality of second heat-conducting branch pipes 44, a second heat-conducting ring wall 45, and a third heat-conducting ring wall 46. The plurality of second heat-conducting branch pipes 44 are distributed in a second preset manner around the first heat-conducting main pipe 41, and the plurality of second heat-conducting branch pipes 44 are set higher than the first heat-conducting branch pipe 42. The second heat-conducting ring wall 45 is sleeved on the outside of the first heat-conducting ring wall 43. The third heat-conducting ring wall 46 is sleeved on the outside of the second heat-conducting ring wall 45, and a second heat-conducting cavity 48 is formed between the outer side of the second heat-conducting ring wall 45 and the inner side of the third heat-conducting ring wall 46. The second heat-conducting branch pipes 44 are connected to the second heat-conducting cavity 48.

[0032] In this embodiment, the structure of the first heat exchange group 4 is further expanded and strengthened to construct a more complex and efficient multi-stage waste heat recovery system. In addition to the aforementioned first heat-conducting main pipe 41, first heat-conducting branch pipe 42, and first heat-conducting ring wall 43, the first heat exchange group 4 also includes multiple second heat-conducting branch pipes 44, second heat-conducting ring walls 45, and third heat-conducting ring walls 46. The multiple second heat-conducting branch pipes 44 are distributed circumferentially around the first heat-conducting main pipe 41 in a second predetermined manner (e.g., radially distributed in another ring offset from the first heat-conducting branch pipe 42 at a certain angle), and their installation position is higher than that of the first heat-conducting branch pipe 42. The second heat-conducting ring wall 45 is fitted outside the first heat-conducting ring wall 43, and the third heat-conducting ring wall 46 is fitted outside the second heat-conducting ring wall 45. Thus, a coaxial second heat-conducting cavity 48 is formed between the outer wall of the second heat-conducting ring wall 45 and the inner wall of the third heat-conducting ring wall 46. The second heat-conducting branch pipes 44 communicate with this second heat-conducting cavity 48.

[0033] This extended structure achieves both vertical and radial stratification of heat recovery. Specifically, the higher-positioned second heat-conducting branch 44 connects to the second heat-conducting cavity 48 (composed of the second heat-conducting ring wall 45 and the third heat-conducting ring wall 46), which is located closer to the high-temperature flue gas outlet of the combustion chamber 31, enabling the recovery of waste heat from the flue gas, which is at a slightly lower temperature but still has considerable heat. The lower-positioned first heat-conducting branch 42 and its connected first heat-conducting cavity 47 (composed of the combustion chamber 31 wall and the first heat-conducting ring wall 43) primarily recover high-grade heat radiated and conducted by the main body of the combustion chamber 31, as well as circumferential convective heat. In this way, the heat exchange medium (such as air) can flow sequentially through heat exchange zones with different temperature gradients: for example, it first enters the high-temperature zone of the first heat-conducting cavity 47 for initial heating, and then enters the slightly lower-temperature second heat-conducting cavity 48 for deeper heating and waste heat recovery, or a parallel flow path can be used for simultaneous heating.

[0034] This embodiment, through a multi-layered nested structure from the inside out (first heat-conducting ring wall 43, second heat-conducting ring wall 45, and third heat-conducting ring wall 46), not only greatly increases the total heat exchange area, but also achieves refined and tiered heat recovery of the circumferential space of the combustion chamber 31 by forming multiple independent heat-conducting cavities. This significantly improves the waste heat recovery efficiency and hot air output temperature of the overall heat exchange component, while making the furnace body 1 more compact.

[0035] In some embodiments, the second heat exchange group 5 includes a second heat-conducting main pipe 51 and a plurality of third heat-conducting branch pipes 52. The second heat-conducting main pipe 51 is disposed in the combustion chamber 31 and is disposed inside the first heat-conducting main pipe 41. The second heat-conducting main pipe 51 is connected to the combustion chamber 31 but is not directly connected to the first heat-conducting main pipe 41. The plurality of third heat-conducting branch pipes 52 are distributed in a third preset manner around the second heat-conducting main pipe 51. A third heat-conducting cavity 53 is provided between the furnace body 1 and the outer side of the third heat-conducting ring wall 46. The third heat-conducting cavity 53 is connected to the third heat-conducting branch pipes 52.

[0036] In this embodiment, the second heat exchange group 5 includes a second heat-conducting main pipe 51 and multiple third heat-conducting branch pipes 52. The second heat-conducting main pipe 51 is disposed inside the combustion chamber 31 and is located inside the first heat-conducting main pipe 41. This means that the second heat-conducting main pipe 51 extends deeper into the high-temperature core region of the combustion chamber 31. The second heat-conducting main pipe 51 communicates with the internal space of the combustion chamber 31, but its flow channel is independent of the flow channel of the first heat-conducting main pipe 41, i.e., it is not directly connected to the first heat-conducting main pipe 41. The multiple third heat-conducting branch pipes 52 are distributed circumferentially around the second heat-conducting main pipe 51 in a third predetermined manner. In addition, there is an annular third heat-conducting cavity 53 between the inner wall of the furnace body 1 and the outer wall of the third heat-conducting ring wall 46. The third heat-conducting branch pipes 52 communicate with this third heat-conducting cavity 53.

[0037] Furthermore, such as Figure 2 and Figure 3 As shown, the second heat conduction pipe 51 is not directly connected to the first heat conduction pipe 41, but it is directly connected to the combustion chamber 31. Specifically, the second heat conduction pipe 51 has an opening at the bottom and is closed at the top. The hottest air in the middle of the combustion chamber 31 can be directly conducted to the outermost third heat conduction cavity 53 through the second heat conduction pipe 51, thus achieving the first diffusion of hot air outward. The surrounding hot air rises and then falls through the first opening 411 to the first heat conduction pipe 41, flowing into the inner first heat conduction cavity 47 and the second heat conduction cavity 48. This achieves a more stable temperature transition. The outermost third heat conduction cavity 53 first insulates or even reverses the second heat conduction cavity 48 and the first heat conduction cavity 47, thus making the temperature around the combustion chamber 31 more balanced, rather than a unidirectional heating output with cold at the top and hot at the bottom. Furthermore, the first heat-conducting cavity 47 is located at the innermost side, while the first heat-conducting branch pipe 42 is placed at the bottom of the first heat-conducting main pipe 41. That is, the air with the lowest temperature will enter the first heat-conducting branch pipe 42, thereby absorbing the heat from the combustion chamber 31. The second heat-conducting branch pipe 44 is placed above the first heat-conducting branch pipe 42 and contains air with a higher temperature. The second heat-conducting cavity 48 is placed between the first heat-conducting cavity 47 and the third heat-conducting cavity 53, which can smoothly transition the temperature within the entire furnace body 1.

[0038] In this embodiment, the design constructs a composite heat exchange path that penetrates deep into the combustion core and utilizes the external space of the furnace body 1. The second heat-conducting main pipe 51, located inside the combustion chamber 31, can be directly immersed in the high-temperature flame and flue gas, absorbing the highest grade of heat to achieve high-intensity, rapid direct heat exchange. The heat exchange medium (such as air) enters from the second heat-conducting main pipe 51, absorbs heat, and is then transported through the third heat-conducting branch pipes 52 distributed around the main pipe to the third heat-conducting cavity 53 between the furnace body 1 and the outermost third heat-conducting ring wall 46. This third heat-conducting cavity 53 is located inside the furnace body 1 but at the outermost edge of all heat exchange ring walls, and its temperature is relatively low. The heat exchange medium flows in this cavity, which can further recover residual heat dissipated from the inner heat-conducting ring walls and the furnace body 1 wall, while also providing a certain degree of cooling and protection for the furnace body 1. This structure cleverly combines the high-intensity direct heat exchange inside the combustion chamber 31 with the low-temperature waste heat recovery of the furnace body 1 interlayer. The second heat exchange group 5 and the first heat exchange group 4 (responsible for upper and circumferential multi-layer heat exchange) work independently yet collaboratively, together forming a three-dimensional heat exchange network that is fully covered and multi-gradient from the combustion core to the outer shell of the furnace body 1. This ensures that the heat generated by combustion is captured and utilized to the maximum extent, thereby greatly improving the thermal efficiency of the entire hot blast stove.

[0039] In some embodiments, the second heat exchange group 5 further includes an annular partition 54 and a branch pipe 55. The annular partition 54 is disposed in the third heat conduction cavity 53 to divide the third heat conduction cavity 53 into a confluence cavity 531 and a branch cavity 532. The confluence cavity 531 is disposed in the upper part of the furnace body 1 and communicates with the third heat conduction branch pipe 52. The branch pipe 55 communicates with the confluence cavity 531 and is distributed circumferentially along the third heat conduction annular wall 46 and is placed in the branch cavity 532.

[0040] In this embodiment, the internal flow channel organization of the second heat exchange group 5 is further optimized to improve heat exchange uniformity and efficiency. The second heat exchange group 5 also includes an annular baffle 54 and branch pipes 55. The annular baffle 54 is disposed inside the third heat conduction cavity 53, and its function is to divide the originally continuous third heat conduction cavity 53 into two independent cavities in the axial direction: a confluence cavity 531 located at the upper part and a branch cavity 532 located at the lower part. The confluence cavity 531 is located in the upper region of the furnace body 1 and is connected to the third heat conduction branch pipe 52 led out from the combustion chamber 31, for collecting the heat exchange medium that has been preliminarily heated flowing out from the high-temperature core area. The branch pipes 55 are connected to this confluence cavity 531, and there are multiple branch pipes 55, which are evenly spaced along the circumference of the third heat conduction ring wall 46. The main body of these branch pipes 55 is arranged in the branch cavity 532.

[0041] This structure enables the heat exchange medium to flow through the third heat-conducting cavity 53 in a process of "first converging, then uniformly distributing". The high-temperature medium flowing out of the second heat-conducting main pipe 51 inside the combustion chamber 31 first enters the converging cavity 531 located at the upper part of the furnace body 1 via the third heat-conducting branch pipe 52. In this cavity, the medium from different branch pipes is mixed to balance the temperature and pressure. Subsequently, the medium is redistributed from the converging cavity 531 and introduced into the lower distributing cavity 532 through multiple circumferentially distributed branch pipes 55. Within the distributing cavity 532, the medium flows downward along the annular space between the outer side of the third heat-conducting ring wall 46 and the inner wall of the furnace body 1 or along a specific path.

[0042] In this embodiment, the mixing effect of the manifold 531 can eliminate the differences in medium parameters at the outlets of each branch pipe caused by uneven combustion, making subsequent heat exchange more stable. The medium is introduced into the branch pipe 532 through the circumferentially evenly distributed branch pipe 55, ensuring that the medium can uniformly fill the entire annular heat exchange space, avoiding medium short circuits or local flow dead zones, thereby maximizing the utilization of the heat exchange area of ​​the entire third heat conduction cavity 53 and improving the uniformity and overall efficiency of waste heat recovery.

[0043] In some embodiments, the second heat exchange group 5 further includes spiral fins 56, which are disposed on the outside of each branch pipe 55, and are used to increase the heat conduction area.

[0044] In this embodiment, to further enhance the heat exchange efficiency of the second heat exchange group 5 within the distribution cavity 532, its structure also includes spiral fins 56. The spiral fins 56 are disposed on the outer wall of each distribution branch pipe 55. Their core function is to increase the heat conduction area.

[0045] Specifically, when the heat exchange medium flows through the branch pipe 55, its heat is transferred through the pipe wall to the surrounding, cooler space of the branch cavity 532 (or the secondary heat exchange medium within the cavity). By adding spiral fins 56 to the outside of the branch pipe 55, the outer surface area of ​​a single branch pipe can be greatly expanded. The spiral structure increases the static heat transfer area and can also disturb the surrounding fluid when the medium flows through, disrupting the laminar boundary layer near the pipe wall and enhancing the degree of turbulence, thereby significantly improving the convective heat transfer coefficient. Therefore, the application of spiral fins 56 makes the branch pipe 55 not only a channel for transporting the medium within the branch cavity 532, but also a core element for efficiently expanding the heat exchange surface.

[0046] This embodiment ensures that the heat distributed from the manifold 531 can be released more quickly and fully into the low-temperature region (or the secondary medium to be heated) in the manifold 532 through the finned branch pipe 55, thereby maximizing the heat exchange efficiency of the third heat conduction chamber 53, the final waste heat recovery stage. This is an important detail optimization to improve the heat recovery capability of the entire hot blast stove system.

[0047] In some embodiments, the smoke exhaust assembly 6 includes a first smoke exhaust base plate 61, a second smoke exhaust base plate 62, a first smoke exhaust side plate 63, a first dust removal cover plate 64, a smoke exhaust fan 6526, a smoke pipe 66, a first smoke exhaust top plate 67, and a second dust removal cover plate 68; the first smoke exhaust base plate 61 is connected to the first heat conduction cavity 47, the second heat conduction cavity 48, and the branch pipe 55 respectively; the second smoke exhaust base plate 62 is disposed below the first smoke exhaust base plate 61; the first smoke exhaust side plate 63 is disposed between the first smoke exhaust base plate 61 and the second smoke exhaust base plate 62, so as to... A first exhaust chamber 69 is formed, and a first ash removal port is provided on the first exhaust side plate 63; a first ash removal cover plate 64 covers the first ash removal port; an exhaust fan 6526 is located on one side of the furnace body 1, and the exhaust fan 6526 is connected to the first exhaust chamber 69; a flue 66 is connected to the output end of the exhaust fan 6526; a first exhaust top plate 67 is located above the confluence chamber 531, and forms a second exhaust chamber with the annular partition 54, and a second ash removal port is provided on the first exhaust top plate 67; a second ash removal cover plate 68 covers the second ash removal port.

[0048] In this embodiment, the smoke exhaust assembly 6 includes a first smoke exhaust base plate 61, a second smoke exhaust base plate 62, a first smoke exhaust side plate 63, a first dust removal cover plate 64, a smoke exhaust fan 6526, a smoke pipe 66, a first smoke exhaust top plate 67, and a second dust removal cover plate 68. The first smoke exhaust base plate 61 is located at the bottom of the assembly and its function is to collect low-temperature flue gas from different heat exchange zones. It is connected to the space where the first heat conduction cavity 47, the second heat conduction cavity 48, and the branch pipe 55 located in the branch cavity 532 (i.e., the branch cavity 532) are located, thereby collecting the flue gas that has completed heat exchange in each circumferential heat exchange layer. The second smoke exhaust base plate 62 is located below the first smoke exhaust base plate 61, and the two are connected by the first smoke exhaust side plate 63, thereby enclosing a flat first smoke exhaust cavity 69.

[0049] A first ash removal port is provided on the first exhaust side plate 63 for maintenance and cleaning of the cavity. A first ash removal cover plate 64 is used to seal the ash removal port when not cleaning. An exhaust fan 6526 is located on one side of the furnace body 1. Its inlet end connects to the first exhaust cavity 69, providing power for the exhaust of flue gas; its outlet end connects to the flue pipe 66, ultimately guiding the flue gas to the chimney or subsequent treatment equipment. Furthermore, a first exhaust top plate 67 is provided above the confluence cavity 531. Together with the annular baffle 54, it forms another second exhaust cavity, used to collect and guide the flue gas from the combustion chamber 31 and the upper heat exchange area. The first exhaust top plate 67 also has a second ash removal port, which is sealed by a second ash removal cover plate 68.

[0050] The structure shown in this embodiment achieves clear zoning and efficient management of the flue gas path. High-temperature flue gas from the core and upper space of combustion chamber 31 first enters the second exhaust chamber, while low-temperature flue gas from each circumferential heat exchange layer (first heat conduction chamber 47, second heat conduction chamber 48) and the final heat exchange zone (diversion chamber 532) is introduced into the first exhaust chamber 69. This facilitates differentiated treatment or mixing based on flue gas temperature and dust content. All exhaust chambers are equipped with sealable ash removal ports (first ash removal port, second ash removal port) to facilitate periodic removal of deposited ash, ensuring smooth flue gas flow and long-term stability of heat exchange efficiency. The entire exhaust assembly 6 works closely with the aforementioned complex heat exchange components, ensuring that the low-temperature flue gas, after sufficient heat extraction, can be discharged from the system in an orderly and reliable manner.

[0051] In some embodiments, the combustion assembly 3 further includes a first combustion pipe 32, a combustion grid 33, a first feed pipe 34, and a first discharge pipe 35. The first combustion pipe 32 is disposed below the combustion chamber 31 and is provided with a heating wire. The combustion grid 33 is embedded in the combustion chamber 31 and is used to receive biomass pellets. The area where the combustion grid 33 is located is the main combustion zone. The first feed pipe 34 is connected to the combustion chamber 31 and is located in the pyrolysis drying zone. The first discharge pipe 35 is connected to the combustion chamber 31 and is disposed opposite to the first feed pipe 34. The area where the first discharge pipe 35 is located is the burnout zone.

[0052] In this embodiment, the combustion assembly 3, in addition to the combustion chamber 31, also includes a first combustion pipe 32, a combustion grid 33, a first feed pipe 34, and a first discharge pipe 35. The first combustion pipe 32 is located directly below the combustion chamber 31 and contains a heating wire to provide an auxiliary heat source during startup or when needed, to ignite the fuel or maintain the temperature at the bottom of the combustion chamber 31, ensuring smooth and stable combustion. The combustion grid 33 is embedded inside the combustion chamber 31, serving to receive biomass pellets and form a fuel layer, while allowing air to pass through the fuel layer from the bottom to aid combustion. The area where the combustion grid 33 is located is defined as the main combustion zone, the core area where the fuel undergoes intense combustion and releases the main heat. The first feed pipe 34 communicates with the combustion chamber 31, conveying biomass pellets from the feed assembly 2 into the combustion chamber 31. The area of ​​the combustion chamber 31 where its outlet is located is defined as the pyrolysis drying zone (or drying pyrolysis zone), where the fuel is first preheated, dried, and begins pyrolysis to release volatiles. The first discharge pipe 35 is also connected to the combustion chamber 31, and its position is opposite to the first feed pipe 34 (for example, located at both ends of the combustion chamber 31), for discharging the ash after combustion. The end area of ​​the combustion chamber 31 where the first discharge pipe 35 is located is defined as the burnout zone, ensuring that the fixed carbon portion of the fuel is completely burned before leaving the combustion chamber 31.

[0053] In this embodiment, biomass pellets enter the pyrolysis drying zone through the first feed pipe 34, where they undergo preheating and volatilization at high temperatures. Fuel, propelled by gravity or mechanical force, moves to the main combustion zone formed by the combustion grille 33, where it mixes thoroughly with air introduced from the bottom (possibly through the first combustion pipe 32 or other air ducts) and undergoes intense combustion. Unburned residue moves to the burnout zone at the other end, where it undergoes final combustion under oxygen-rich conditions, and the ash is discharged through the first discharge pipe 35. Throughout the process, the heating wire at the bottom of the first combustion pipe 32 serves as a reliable start-up and stable combustion guarantee. This ensures that the fuel undergoes a complete, orderly, and efficient thermal conversion process, which is crucial for achieving a high burnout rate and stable combustion conditions.

[0054] In some embodiments, the feeding assembly 2 includes a second feeding pipe 21, a feeding hopper 22, a spiral feeding blade 23, a drive unit 24, an air guide pipe 25, and a fan 26. One end of the second feeding pipe 21 is connected to the first feeding pipe 34; the feeding hopper 22 is disposed at the other end of the second feeding pipe 21; the spiral feeding blade 23 is disposed inside the second feeding pipe 21; the drive unit 24 is connected to the spiral feeding blade 23; the air guide pipe 25 is connected to the connection between the second feeding pipe 21 and the first feeding pipe 34; the fan 26 is connected to the other end of the air guide pipe 25, and the fan 26 is disposed on the outside of the furnace body 1.

[0055] In this embodiment, the feeding assembly 2 is a system integrating storage, conveying, and auxiliary air supply. The feeding assembly 2 includes a second conveying pipe 21, a feeding hopper 22, a spiral feeding blade 23, a drive unit 24, an air guide duct 25, and a fan 26. The second conveying pipe 21 serves as the main conveying channel, with one end connected to the first conveying pipe 34 of the combustion assembly 3, ultimately delivering fuel into the combustion chamber 31. The feeding hopper 22 is located at the other end (i.e., the starting end) of the second conveying pipe 21, used to store a certain amount of biomass pellets and continuously supply them to the conveying pipe by gravity. The spiral feeding blade 23 is coaxially arranged inside the second conveying pipe 21 and is the core component for performing mechanical conveying. The drive unit 24 (such as a motor) is drive-connected to the spiral feeding blade 23, providing it with rotational power; the feeding amount can be precisely adjusted by controlling the rotational speed of the drive unit 24. The air guide duct 25 is connected at the connection point between the second conveying pipe 21 and the first conveying pipe 34. The blower 26 is located on the outside of the furnace body 1, and its air outlet is connected to the other end of the air duct 25.

[0056] In this embodiment, biomass pellets fall from the feed hopper 22 into the second conveying pipe 21 and are pushed forward by rotating spiral feeding blades 23, ensuring the continuity and stability of feeding and effectively preventing material bridging in the pipe. Simultaneously, the airflow generated by the blower 26 is injected into the connection between the second conveying pipe 21 and the first conveying pipe 34 through the air guide duct 25, serving as primary air or feeding air to assist in carrying and accelerating the fuel pellets into the combustion chamber 31, especially helping to overcome the resistance of pipe bends or vertical sections. The airflow is initially mixed with the fuel before entering the combustion chamber 31, providing some oxygen for the initial combustion of the fuel. The airflow also has a cooling and purging effect on the conveying pipe and the feeding mechanism. This embodiment, through the combination of spiral mechanical feeding and pneumatic assistance, ensures a uniform, stable, and controllable fuel supply to the combustion chamber 31 under various operating conditions, which is an important foundation for ensuring the continuous, efficient, and stable operation of the hot blast stove.

[0057] Unlike existing technologies, the above technical solution includes a biomass pellet hot air furnace comprising a furnace body 1, a feeding assembly 2, a combustion assembly 3, a heat exchange assembly, and a flue gas assembly 6. The combustion assembly 3 is located within the furnace body 1, and its combustion chamber 31 is sequentially divided into a drying pyrolysis zone, a main combustion zone, and a burnout zone along the biomass pellet conveying direction, achieving orderly zoned combustion of fuel preheating, complete combustion, and total burnout. Simultaneously, the heat exchange assembly includes a first heat exchange group 4 positioned above the combustion assembly 3 and a second heat exchange group 5 positioned around the combustion assembly 3, forming a three-dimensional, multi-layered waste heat recovery structure. This technical solution scientifically partitions the fuel combustion process spatially, extending the flue gas flow and residence time, ensuring complete combustion and burnout of the fuel, thereby improving combustion efficiency from the source. Furthermore, through the synergistic effect of the first heat exchange group 4 and the second heat exchange group 5, heat dissipated above and around the combustion chamber 31 can be captured and recovered in an all-round and efficient manner, significantly reducing flue gas heat loss. This technical solution significantly improves the combustion efficiency and burnout rate of biomass pellets through a zoned combustion design; and achieves efficient and full recovery of combustion waste heat through a three-dimensional arrangement of the first heat exchange group 4 and the second heat exchange group 5, thereby greatly improving the overall thermal efficiency and energy utilization rate of the hot blast stove.

[0058] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0059] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods of various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0060] The above description is only a part of the embodiments of the present invention and does not limit the scope of protection of the present invention. Any equivalent device or equivalent process transformation made based on the content of the present invention specification and drawings, or direct or indirect application in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A biomass pellet hot air furnace, characterized in that, include: Furnace body; A feeding assembly is disposed on one side of the furnace body, and the feeding assembly is used to convey biomass pellets; A combustion assembly is disposed inside the furnace body. The combustion assembly includes a combustion chamber, which is divided into a drying pyrolysis zone, a main combustion zone, and a burnout zone along the conveying direction of the biomass pellets. The combustion chamber is connected to the feeding assembly. The heat exchange assembly includes a first heat exchange group and a second heat exchange group. The first heat exchange group is disposed above the combustion assembly, and the second heat exchange group is disposed circumferentially on the combustion assembly. The first heat exchange group and the second heat exchange group are used to recover waste heat from the combustion chamber. A smoke exhaust assembly is disposed on the other side of the furnace body. The smoke exhaust assembly is connected to the combustion assembly and is used to exhaust the flue gas from the combustion chamber.

2. The biomass pellet hot air furnace according to claim 1, characterized in that, The first heat exchange group includes: The first heat conduction main pipe is located above the combustion chamber; Multiple first heat-conducting branch pipes are distributed in a first preset manner around the first heat-conducting main pipe, and the first heat-conducting branch pipes are connected to the first heat-conducting main pipe. A first heat-conducting ring wall is sleeved on the outside of the combustion chamber, and a first heat-conducting cavity is formed between the inner side of the first heat-conducting ring wall and the outer side of the combustion chamber. The first heat-conducting branch pipe is connected to the first heat-conducting cavity.

3. The biomass pellet hot air furnace according to claim 2, characterized in that, The upper end of the first heat conduction pipe is provided with a first opening, and the first opening is positioned facing upwards towards the combustion chamber. The lower end of the first heat conduction pipe is closed, and the diameter of the first heat conduction pipe is smaller than that of the combustion chamber.

4. The biomass pellet hot air furnace according to claim 2, characterized in that, The first heat exchange group also includes: Multiple second heat-conducting branch pipes are distributed in a second preset manner around the first heat-conducting main pipe, and the multiple second heat-conducting branch pipes are set higher than the first heat-conducting branch pipe; The second heat-conducting ring wall is sleeved on the outside of the first heat-conducting ring wall; The third heat-conducting ring wall is sleeved on the outside of the second heat-conducting ring wall, and a second heat-conducting cavity is formed between the outer side of the second heat-conducting ring wall and the inner side of the third heat-conducting ring wall. The second heat-conducting branch pipe is connected to the second heat-conducting cavity.

5. The biomass pellet hot air furnace according to claim 4, characterized in that, The second heat exchange group includes: A second heat conduction pipe is disposed in the combustion chamber and inside the first heat conduction pipe. The second heat conduction pipe is connected to the combustion chamber but is not directly connected to the first heat conduction pipe. Multiple third heat-conducting branches are distributed in a third preset manner along the circumference of the second heat-conducting main pipe; There is a third heat-conducting cavity between the furnace body and the outer side of the third heat-conducting ring wall, and the third heat-conducting cavity is connected to the third heat-conducting branch pipe.

6. The biomass pellet hot air furnace according to claim 5, characterized in that, The second heat exchange group also includes: An annular baffle is disposed in the third heat conduction cavity to divide the third heat conduction cavity into a manifold cavity and a branch cavity. The manifold cavity is disposed in the upper part of the furnace body and is connected to the third heat conduction branch pipe. The branch pipes are connected to the manifold, and are distributed circumferentially along the third heat-conducting ring wall and placed inside the branch cavity.

7. The biomass pellet hot air furnace according to claim 6, characterized in that, The second heat exchange group also includes: Spiral fins are disposed on the outer side of each of the aforementioned branch pipes, and the spiral fins are used to increase the heat conduction area.

8. The biomass pellet hot air furnace according to claim 6, characterized in that, The smoke extraction assembly includes: The first exhaust bottom plate is connected to the first heat conduction cavity, the second heat conduction cavity, and the branch pipe, respectively. The second smoke exhaust base plate is located below the first smoke exhaust base plate; The first smoke exhaust side plate is disposed between the first smoke exhaust bottom plate and the second smoke exhaust bottom plate to form a first smoke exhaust cavity. The first smoke exhaust side plate is provided with a first ash removal port. The first dust removal cover plate covers the first dust removal port; A smoke exhaust fan is installed on one side of the furnace body, and the smoke exhaust fan is connected to the first smoke exhaust chamber; The flue is connected to the output end of the exhaust fan; The first smoke exhaust top plate is located above the confluence cavity and forms a second smoke exhaust cavity with the annular partition. The first smoke exhaust top plate is provided with a second ash removal port. The second dust removal cover plate is placed over the second dust removal port.

9. The biomass pellet hot air furnace according to claim 1, characterized in that, The combustion assembly also includes: A first combustion tube is disposed below the combustion chamber, and a heating wire is provided inside the first combustion tube; A combustion grille is embedded in the combustion chamber. The combustion grille is used to receive biomass pellets, and the area where the combustion grille is located is the main combustion zone. The first feed pipe is connected to the combustion chamber, and the area where the first feed pipe is located is the pyrolysis drying zone; The first discharge pipe is connected to the combustion chamber and is disposed opposite to the first conveying pipe. The area where the first discharge pipe is located is the burnout zone.

10. The biomass pellet hot air furnace according to claim 9, characterized in that, The feeding assembly includes: A second conveying pipe, one end of which is connected to the first conveying pipe; A feed hopper is located at the other end of the second conveying pipe; Spiral feeding blades are installed inside the second conveying pipe; The drive unit is connected to the spiral feed blades via a transmission. An air duct is connected at the junction of the second conveying pipe and the first conveying pipe; A blower is connected to the other end of the air duct, and the blower is located on the outside of the furnace body.

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