Biomass double-hearth combustion furnace with direct-flow and rotational-flow combustors arranged at bottom

Abstract

The invention discloses a biomass double-hearth combustion furnace with a direct-flow burner and a rotational-flow burner arranged at the bottom, and relates to the technical field of combustion equipment. The problems that an existing combustion device is insufficient in adaptability to the particle size of biomass particles, and large-particle biomass is difficult to burn out completely are solved. A direct-current burner is connected with the outer wall of an inner-layer furnace and the inner wall of an outer-layer furnace through a posture adjusting assembly, a turbulent burner and an inner-layer furnace combustion chamber which are embedded inside and outside are installed at the bottom of the inner-layer furnace, a through turbulent burner is installed at the bottom of the inner-layer furnace combustion chamber, and a third smoke exhaust channel is formed in the upper portion of the inner-layer furnace. An outlet of a first smoke exhaust channel in the upper portion of the outer-layer furnace is communicated with a third smoke exhaust channel, an outlet of a second smoke exhaust channel is communicated with an inlet of a cyclone separator, an outlet in the upper end of the cyclone separator is communicated with an inlet of a turbulent burner through a combustible gas connecting pipeline, and an outlet in the lower end of the cyclone separator is communicated with a combustion chamber of the inner-layer furnace through a carbon residue channel. The biomass burner is used for achieving sufficient burning of large-particle biomass, and the burn-off rate is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of combustion equipment, in particular to a biomass double-hearth combustion furnace with bottom-mounted direct current and swirl burners. Background Art

[0002] Against the backdrop of global energy transformation, the pace of application of clean and renewable energy continues to accelerate, and the importance of reducing carbon emissions from energy has become increasingly prominent. The extensive use of traditional fossil fuels will lead to a sharp increase in the concentration of carbon dioxide in the atmosphere. As a renewable clean energy source with near-zero carbon emissions, biomass plays an important role in replacing fossil fuels and reducing greenhouse gas emissions. my country has abundant biomass resources, including crop straw, forestry processing residues, livestock and poultry breeding waste, and urban organic waste. The effective utilization of these biomass resources can not only significantly reduce dependence on traditional fossil energy, but also provide important support for my country to achieve its "dual carbon" goals.

[0003] During the biomass fuel processing process, the raw materials are usually ground into pellets using a grinder before being fed into a furnace for combustion. However, the grindability of different biomasses varies. For softer raw materials, the grinding process is relatively easy, requiring only a small amount of power to grind into small particles. For raw materials with high fiber content or strong toughness, the particle size is larger under the same grinder output conditions. For traditional combustion devices, to ensure complete combustion of the biomass in the furnace, the grinder output needs to be increased. However, this approach increases energy consumption and reduces overall economic efficiency.

[0004] In summary, in order to improve economic efficiency, it is necessary to develop a combustion device with wide particle size adaptability. Under the condition of constant grinding output, this device can simultaneously achieve the full combustion of small-particle / large-particle biomass, effectively improve the system's adaptability to biomass raw materials with different grindability, and ultimately achieve the goal of efficient and economical utilization of biomass. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem that the existing combustion device has insufficient adaptability to the particle size of biomass particles and large biomass particles are difficult to burn completely, and further provide a biomass double-hearth combustion furnace with bottom-mounted direct current and swirl burners.

[0006] The technical solution of the present invention is:

[0007] A biomass double-hearth combustion furnace with DC and swirl burners placed at the bottom, the biomass double-hearth combustion furnace includes an inner furnace 6 and an outer furnace 7 coaxially nested inside and outside, the outer wall surface of the inner furnace 6 and the inner wall surface of the outer furnace 7 share a continuous wall surface, and multiple DC burners are evenly arranged along the circumference of the bottom of the outer furnace 7. The DC burner is connected to the outer wall of the inner furnace 6 and the inner wall of the outer furnace 7 through a posture adjustment component 16. The posture adjustment component 16 can control the vertical angle and horizontal angle of the DC burner in real time according to different working conditions. The center position of the bottom of the inner furnace 6 passes through the inner furnace 6 and the inner furnace 7 is connected. The inner furnace combustion chamber 3 has a swirl burner installed at the bottom thereof, a third smoke exhaust channel 8 is provided on the upper portion of the inner furnace 6, and a first smoke exhaust channel 9 and a second smoke exhaust channel 12 which can independently control the opening and closing and the opening degree are provided on the upper portion of the outer furnace 7. The outlet of the first smoke exhaust channel 9 is connected to the third smoke exhaust channel 8, and the outlet of the second smoke exhaust channel 12 is connected to the inlet of the cyclone separator 13. The upper outlet of the cyclone separator 13 is connected to the inlet of the swirl burner through the combustible gas connecting pipe 15, and the lower outlet of the cyclone separator 13 is connected to the inner furnace combustion chamber 3 through the residual carbon channel 14.

[0008] Furthermore, the inner furnace 6 and the outer furnace 7 adopt a coaxially nested cylindrical partitioned combustion structure.

[0009] Furthermore, each DC burner includes a primary air channel 4 and a DC secondary air channel 5 , and the DC secondary air channel 5 is coaxially arranged on the periphery of the primary air channel 4 .

[0010] Furthermore, the included angle between the center line of the primary air channel 4 and the projection of the furnace bottom on the vertical plane is , 30°< <60°.

[0011] Furthermore, the angle between the projection line of the center line of the primary air channel 4 on the bottom surface of the furnace and the horizontal center line of the bottom surface of the furnace is , 30°< <60°.

[0012] Furthermore, the posture adjustment component 16 includes a mounting ring 16-1 coaxially nested on the outside of the DC secondary air channel 5, and two vertically arranged first rotating shafts 16-2 are respectively provided on both side walls of the DC secondary air channel 5. The other ends of the two first rotating shafts 16-2 are rotatably connected to the left and right ends of the mounting ring 16-1, respectively. A first driven bevel gear 16-3 is installed on the end of one of the first rotating shafts 16-2, and a first driving bevel gear 16-4 meshing with the first driven bevel gear 16-3 is provided on the side of the first driven bevel gear 16-3. The first driving bevel gear 16-4 is installed on the end of the rotating shaft of the first reduction motor 16-5 arranged vertically above. The first reduction motor 16-5 is fixedly connected to the mounting ring 16-1 through a motor support plate 16-6. Two second rotating shafts 16-7 arranged vertically are respectively provided at the front and rear ends of the mounting ring 16-1, and the other ends of the two second rotating shafts 16-7 are rotatably connected to the lower parts of two vertically oppositely arranged channel connecting plates 16-8, and the upper parts of the two channel connecting plates 16-8 are fixedly connected to the outer wall of the inner furnace 6 and the inner wall of the outer furnace 7 respectively. A second driven bevel gear 16-9 is installed at the end of one of the second rotating shafts 16-7, and a second driving bevel gear 16-10 meshing with it is provided on the side of the second driven bevel gear 16-9. The second driving bevel gear 16-10 is installed on the end of the rotating shaft of the second reduction motor 16-11 arranged vertically above, and the second reduction motor 16-11 is installed on the channel connecting plate 16-8.

[0013] Furthermore, the swirl burner includes a combustible gas channel 1 and a swirl secondary air channel 2. The swirl secondary air channel 2 is coaxially arranged on the periphery of the combustible gas channel 1. The swirl secondary air channel 2 is provided with a plurality of axial swirl blades uniformly arranged along the circumferential direction.

[0014] Furthermore, an air supply inlet is provided at the end of the carbon residue channel 14 , and the air supply inlet is connected to an external air supply source.

[0015] Furthermore, the biomass dual-hearth combustion furnace further includes a first valve 10 and a second valve 11 , which are installed in the first smoke exhaust channel 9 and the second smoke exhaust channel 12 , respectively.

[0016] Furthermore, the first valve 10 and the second valve 11 are pneumatic or electric regulating valves.

[0017] Compared with the prior art, the present invention has the following effects:

[0018] 1. This invention utilizes a dual-hearth design coupled with an inner and outer furnace structure to create a bidirectional heat cycle system, achieving fully adaptive and efficient combustion of biomass particles of varying particle sizes. In conventional combustion furnaces, small-sized biomass particles can be fully burned after adding biomass fuel. However, large biomass particles are difficult to completely burn within the same residence time, resulting in a high carbon content in the fly ash, which in turn reduces boiler operating efficiency.

[0019] 2. This invention significantly enhances fuel adaptability through a dual-furnace design and a coupled structure of inner and outer furnaces. When the biomass particles are smaller, the burnout time is short, allowing them to fully combust in the outer furnace 7 and be discharged through the top first exhaust duct 9. However, when the biomass particles are larger, the burnout time is longer, and the particles undergo initial combustion in the outer furnace 7. The residual carbon and combustible gas are then recycled through the system into the inner furnace combustion chamber 3 for secondary combustion, extending the combustion time until they are completely burned and discharged in the inner furnace 6.

[0020] 3. The inner and outer furnaces of this invention share a highly thermally conductive wall surface, enabling interactive transfer and coordinated utilization of combustion heat. When the inner and outer furnaces simultaneously burn biomass pellets, heat from the outer furnace 7 is transferred to the inner furnace 6 via the shared wall surface, providing auxiliary heat energy and ensuring stable combustion in the combustion zone of the inner furnace 6. Simultaneously, heat from the inner furnace 6 is reversely transferred to the outer furnace 7, forming a bidirectional heat transfer mechanism and achieving a complementary thermal cycle effect. In summary, the present invention can simultaneously meet the burnout requirements of both small and large-sized biomass pellets. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic structural diagram of a biomass double-hearth combustion furnace with bottom-mounted direct current and swirl burners according to the present invention; Figure 2 yes Figure 1 A-direction view; Figure 3 This is an axonometric diagram of a posture adjustment assembly in a biomass dual-hearth combustion furnace with bottom-mounted direct current and swirl burners according to the present invention; Figure 4 The present invention is a schematic diagram of the structure of a posture adjustment component in a biomass double-hearth combustion furnace with direct current and swirl burners placed at the bottom.

[0022] In the figure: 1. Combustible gas channel; 2. Swirl secondary air channel; 3. Inner furnace combustion chamber; 4. Primary air channel; 5. DC secondary air channel; 6. Inner furnace; 7. Outer furnace; 8. Third smoke exhaust channel; 9. First smoke exhaust channel; 10. First valve; 11. Second valve; 12. Second smoke exhaust channel; 13. Cyclone separator; 14. Residual carbon channel; 15. Combustible gas connecting pipe; 16. Posture adjustment component; 16-1. Mounting ring; 16-2. First rotating shaft; 16-3. First driven bevel gear; 16-4. First driving bevel gear; 16-5. First reduction motor; 16-6. Motor support plate; 16-7. Second rotating shaft; 16-8. Channel connecting plate; 16-9. Second driven bevel gear; 16-10. Second driving bevel gear; 16-11. Second reduction motor. DETAILED DESCRIPTION

[0023] Specific implementation method 1: Combination Figures 1 to 4 Explanation of this embodiment: This embodiment is a biomass double-hearth combustion furnace with DC and swirl burners at the bottom. The biomass double-hearth combustion furnace includes an inner furnace 6 and an outer furnace 7 coaxially nested inside and outside. The outer wall surface of the inner furnace 6 and the inner wall surface of the outer furnace 7 share a continuous wall surface. A plurality of DC burners are evenly arranged along the circumference of the bottom of the outer furnace 7. The DC burners are connected to the outer wall of the inner furnace 6 and the inner wall of the outer furnace 7 through a posture adjustment component 16. The posture adjustment component 16 can control the vertical angle and horizontal angle of the DC burner in real time according to different working conditions. The center of the bottom of the inner furnace 6 The position is connected to the inner furnace combustion chamber 3, and a swirl burner is installed at the bottom of the inner furnace combustion chamber 3. A third smoke exhaust channel 8 is provided on the upper part of the inner furnace 6, and a first smoke exhaust channel 9 and a second smoke exhaust channel 12 which can be independently controlled to open and close and the opening degree are provided on the upper part of the outer furnace 7. The outlet of the first smoke exhaust channel 9 is connected to the third smoke exhaust channel 8, and the outlet of the second smoke exhaust channel 12 is connected to the inlet of the cyclone separator 13. The upper end outlet of the cyclone separator 13 is connected to the inlet of the swirl burner through the combustible gas connecting pipe 15, and the lower end outlet of the cyclone separator 13 is connected to the inner furnace combustion chamber 3 through the residual carbon channel 14.

[0024] The biomass fuel and external air are respectively sent into the outer furnace 7 through the primary air channel 4 and the DC secondary air channel 5 for the first combustion; the inner furnace combustion chamber 3, the combustible gas channel 1 and the swirl secondary air channel 2 are all arranged at the bottom of the inner furnace 6, the combustible gas channel 1 is used to transport the combustible gas generated by the incomplete combustion of the biomass in the outer furnace 7 to the inner furnace 6 for circulating secondary air combustion, and the swirl secondary air channel 2 is used to provide a swirl airflow for the combustion of the residual carbon, so that it forms a swirl combustion in the inner furnace 6; the inner furnace 6 is connected to the third smoke exhaust channel 8, and when the residual carbon completes the second combustion, the smoke is discharged from the third smoke exhaust channel 8; the top of the outer furnace 7 is connected to the first smoke exhaust channel 9 and the second smoke exhaust channel 12, wherein the first smoke exhaust channel 9 is provided with a first valve 10 at the front end, and the second smoke exhaust channel 12 is provided with a second valve 10 at the front end. A second valve 11 is provided at the front end of the channel 12, and the outlet of the second smoke exhaust channel 12 is connected to the cyclone separator 13. When the particle size of the biomass particles to be burned is small, the biomass fuel can be fully burned. At this time, the first valve 10 is opened, and the smoke is discharged through the first smoke exhaust channel 9; when the particle size of the biomass particles is large, the burnout time is relatively long, and the biomass fuel cannot be fully burned. At this time, the second valve 11 is opened, and the combustible gas and residual carbon enter the cyclone separator 13 through the second smoke exhaust channel 12; the upper end outlet of the cyclone separator 13 is connected to the combustible gas channel 1 through the combustible gas connecting pipe 15, and the lower end of the cyclone separator 13 is connected to the residual carbon channel 14, which is connected to the inner furnace combustion chamber 3, thereby forming a circulating secondary combustion path for the residual carbon.

[0025] Specific implementation method 2: Combination Figures 1 to 4 To illustrate this embodiment, the inner furnace 6 and the outer furnace 7 of this embodiment adopt a coaxially nested cylindrical partitioned combustion structure. With this arrangement, the inner furnace 6 and the outer furnace 7 adopt a coaxially nested cylindrical cavity structure, so that the outer wall surface of the inner furnace 6 and the inner wall surface of the outer furnace 7 share a continuous wall surface. When burning large-particle biomass, the inner and outer furnaces operate synchronously, relying on the shared high thermal conductivity wall surface to achieve two-way and efficient heat transfer. The high-temperature heat energy released by the combustion of the outer furnace 7 provides a stable auxiliary heat source for the continuous combustion of the biomass in the inner furnace 6; the heat generated by the inner furnace 6 is reversely conducted to the outer furnace 7 to maintain the high-temperature combustion environment of the outer furnace 7. This two-way heat transfer mechanism forms a complementary heat cycle system, which effectively improves the stability and thermal efficiency of the double-layer furnace combustion process. The other components and connection relationships are the same as those in the first specific embodiment.

[0026] In this embodiment, the dual-furnace structure is highly adaptable to varying biomass particle sizes. When the biomass particle size is small, the burnout time is short, allowing for full combustion in the outer furnace, where it is then exhausted through the first exhaust duct 9 at the top. Conversely, when the biomass particle size is large, the burnout time is extended accordingly. The biomass undergoes initial combustion in the outer furnace, with the resulting char and combustible gas circulating through the system into the inner furnace for continued combustion. Furthermore, the inner and outer furnaces utilize a shared, highly conductive wall surface to achieve bidirectional heat transfer and complementarity, ultimately ensuring that the biomass particles are completely burned and exhausted in the inner furnace.

[0027] Specific implementation method three: Combination Figures 1 to 4 To describe this embodiment, each DC burner includes a primary air duct 4 and a DC secondary air duct 5. The DC secondary air duct 5 is coaxially arranged around the primary air duct 4. This arrangement coaxially transports biomass fuel and DC secondary air into the outer furnace 7. Other components and connections are identical to those in the first or second embodiment.

[0028] In this embodiment, the number of the direct current burners is four.

[0029] Specific implementation method four: Combination Figures 1 to 4 To illustrate this embodiment, the included angle between the center line of the primary air duct 4 and the bottom surface of the furnace on the vertical plane is , 30°< <60°. With this setting, the vertical angle It is adjustable and used to directional guide the biomass fuel and secondary air flow into the combustion zone of the outer furnace 7 in a spiral trajectory to enhance the mixing efficiency of the fuel and air. Other components and connection relationships are the same as those of the specific embodiments 1, 2 or 3.

[0030] Specific implementation method five: Combination Figures 1 to 4 In this embodiment, the angle between the projection line of the center line of the primary air duct 4 on the bottom surface of the furnace and the horizontal center line of the bottom surface of the furnace is , 30°< <60°. With this setting, the horizontal angle It is adjustable and used to directional guide the biomass fuel and secondary air flow into the combustion zone of the outer furnace 7 in a spiral trajectory to enhance the mixing efficiency of the fuel and air. Other components and connection relationships are the same as those of the specific embodiments 1, 2, 3 or 4.

[0031] Specific implementation method six: combination Figures 1 to 4Describing this embodiment, the posture adjustment component 16 of this embodiment includes a mounting ring 16-1 coaxially nested on the outside of the DC secondary air channel 5, and two side walls of the DC secondary air channel 5 are respectively provided with two vertically arranged first rotating shafts 16-2, and the other ends of the two first rotating shafts 16-2 are respectively rotatably connected to the left and right ends of the mounting ring 16-1, and a first driven bevel gear 16-3 is installed at the end of one of the first rotating shafts 16-2, and a first driving bevel gear 16-4 is meshed with the first driven bevel gear 16-3 on the side thereof, and the first driving bevel gear 16-4 is installed at the end of the rotating shaft of the first reduction motor 16-5 arranged vertically above, and the first reduction motor 16-5 is connected to the mounting ring 16-1 through a motor support plate 16-6. Fixed connection, two second rotating shafts 16-7 arranged vertically are respectively provided at the front and rear ends of the mounting ring 16-1, and the other ends of the two second rotating shafts 16-7 are respectively rotatably connected to the lower parts of the two channel connecting plates 16-8 arranged vertically opposite to each other, and the upper parts of the two channel connecting plates 16-8 are respectively fixedly connected to the outer wall of the inner furnace 6 and the inner wall of the outer furnace 7, and a second driven bevel gear 16-9 is installed at the end of one of the second rotating shafts 16-7, and a second driving bevel gear 16-10 is provided on the side of the second driven bevel gear 16-9, which is meshed with each other. The second driving bevel gear 16-10 is installed at the end of the rotating shaft of the second reduction motor 16-11 arranged vertically above, and the second reduction motor 16-11 is installed on the channel connecting plate 16-8. With such an arrangement, during operation, biomass fuel is input through the primary air channel 4 at the bottom of the outer furnace 7, and at the same time, DC secondary air is injected at a preset inclination angle through the coaxially arranged DC secondary air channel 5. By adjusting the vertical angle Angle with horizontal The structure is designed to be adjustable and can directionally guide the biomass fuel and the secondary air flow into the combustion zone of the outer furnace 7 in a spiral trajectory.

[0032] Specifically, when it is necessary to adjust the vertical angle of the DC burner When the second reduction motor 16-11 drives the second active bevel gear 16-10 to rotate, the second active bevel gear 16-10 is engaged with the second driven bevel gear 16-9, thereby driving the mounting ring 16-1 to swing around the second rotating shaft 16-7; when the horizontal angle of the DC burner needs to be adjusted When the first reduction motor 16-5 drives the first driving bevel gear 16-4 to rotate, the first driving bevel gear 16-4 engages with the first driven bevel gear 16-3, thereby driving the DC burner to swing around the first rotating shaft 16-2. The other components and connection relationships are the same as those of the specific embodiments 1, 2, 3, 4 or 5.

[0033] Specific implementation method seven: combination Figures 1 to 4To describe this embodiment, the swirl burner comprises a combustible gas channel 1 and a swirl secondary air channel 2. The swirl secondary air channel 2 is coaxially arranged around the outer periphery of the combustible gas channel 1 and is equipped with a number of axial swirl blades evenly spaced along the circumference. With this arrangement, the inner furnace combustion chamber 3, combustible gas channel 1, and swirl secondary air channel 2 are all located at the bottom of the inner furnace 6. The combustible gas channel 1 is the channel through which the combustible gas generated by the incomplete combustion of biomass in the outer furnace 7 enters the inner furnace 6 for circulating secondary air combustion. Other components and connections are identical to those in Specific Embodiments 1, 2, 3, 4, 5, or 6.

[0034] Specific implementation method eight: combination Figures 1 to 4 To explain this embodiment, an air inlet is provided at the end of the char duct 14, which is connected to an external air supply source. This arrangement connects the char duct 14 to the external air supply system, allowing the biomass combustion char from the lower outlet of the cyclone separator 13 to be transported by external air into the inner furnace combustion chamber 3 for secondary combustion. The remaining components and connections are identical to those of Embodiments 1, 2, 3, 4, 5, 6, or 7.

[0035] Specific implementation method nine: combination Figures 1 to 4 To illustrate this embodiment, the biomass dual-hearth combustion furnace of this embodiment further includes a first valve 10 and a second valve 11, which are respectively installed in the first smoke exhaust channel 9 and the second smoke exhaust channel 12. In this arrangement, the first valve 10 is provided at the front end of the first smoke exhaust channel 9, and the second valve 11 is provided at the front end of the second smoke exhaust channel 12. The outlet of the second smoke exhaust channel 12 is connected to the cyclone separator 13. When the particle size of the biomass particles to be burned is small, the biomass fuel can be fully burned. At this time, the first valve 10 is opened, and the smoke is discharged through the first smoke exhaust channel 9. When the particle size of the biomass particles is large, the burnout time is relatively long, and the biomass fuel cannot be fully burned. At this time, the second valve 11 is opened, and the combustible gas and residual carbon enter the cyclone separator 13 through the second smoke exhaust channel 12. The other components and connection relationships are the same as those of the specific embodiments one, two, three, four, five, six, seven or eight.

[0036] Specific implementation method ten: Combination Figures 1 to 4 To explain this embodiment, the first valve 10 and the second valve 11 are pneumatic or electric regulating valves. With this arrangement, the first valve 10 and the second valve 11 independently control the opening and closing of the first and second exhaust channels 9, 12, respectively, to achieve switching between biomass fuel combustion modes. This allows biomass to be burned directly in the outer furnace 7 and then exhausted through the first exhaust channel 9, or it can be separated through the second exhaust channel 12 and then further burned in the cyclone separator 13. Other components and connections are the same as those of the first, second, third, fourth, fifth, sixth, seventh, eighth, or ninth embodiments.

[0037] How it works

[0038] Combine Figures 1 to 4 The operating principle of the present invention's dual-hearth biomass combustion furnace with bottom-mounted direct current and swirl burners is described below. During operation, biomass fuel is introduced through primary air duct 4 at the bottom of the outer furnace 7. Simultaneously, direct current secondary air is injected at a preset angle through coaxial direct current secondary air duct 5. Together, these two gases form a spiral upward trajectory at the bottom of the outer furnace, forming a swirl flame.

[0039] When the biomass particle size is smaller, the required burnout time is correspondingly shorter. Under these conditions, complete burnout is achieved solely through the outer furnace 7. With the first valve 10 open and the second valve 11 closed, the combustion products from the outer furnace 7 are discharged directly through the second exhaust duct 12 at the top. During this process, the inner furnace 6 is not in use. To prevent damage from high temperatures, some swirl secondary air is introduced for cooling.

[0040] When processing large-particle biomass, the system activates a dual-furnace collaborative mode due to the longer burnout time required. The biomass particles initially undergo preliminary combustion in the outer furnace 7. When the combustion products reach the ascending flue, the second valve 11 opens and the first valve 10 closes. The char and combustible gas produced by this initial combustion flow through the second exhaust duct 12 and enter the cyclone separator 13. Centrifugal separation efficiently separates the char from the combustible gas. The separated combustible gas is then connected to the combustible gas channel 1 via the combustible gas connection pipe 15 at the upper end of the cyclone separator 13. It then enters the inner furnace combustion chamber, where it is thoroughly mixed with the swirling secondary air and intensely combusted under high temperatures. Simultaneously, the char passes through the char channel 14 at the lower end of the cyclone separator 13 and, under the influence of the external air supply system, is blown into the inner furnace combustion chamber for post-combustion. It then enters the inner furnace 6 to complete the subsequent burnout process. Finally, the flue gas generated by the complete combustion of the combustible gas and char in the inner furnace 6 is discharged from the system through the third exhaust duct 8, completing the combustion cycle.

[0041] When burning large biomass particles, the inner and outer furnaces operate synchronously, leveraging their shared, highly conductive wall surface to achieve efficient, two-way heat transfer. The high-temperature heat released by the outer furnace (7) provides a stable auxiliary heat source for the continued combustion of biomass in the inner furnace (6). Heat generated by the inner furnace (6) is then transferred back to the outer furnace (7), maintaining the high-temperature combustion environment there. This two-way heat transfer mechanism forms a complementary thermal cycle system, effectively improving the stability and thermal efficiency of the dual-furnace combustion process.

[0042] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A biomass double-hearth combustion furnace with bottom-mounted direct current and swirl burners, characterized by: The biomass double-hearth combustion furnace comprises an inner furnace (6) and an outer furnace (7) coaxially nested inside and outside, the outer wall surface of the inner furnace (6) and the inner wall surface of the outer furnace (7) share a continuous wall surface, a plurality of DC burners are evenly arranged along the circumference of the bottom of the outer furnace (7), the DC burners are connected to the outer wall of the inner furnace (6) and the inner wall of the outer furnace (7) through a posture adjustment component (16), the posture adjustment component (16) can control the vertical angle and the horizontal angle of the DC burner in real time according to different working conditions, the center position of the bottom of the inner furnace (6) is connected to the inner furnace combustion chamber (3), the inner furnace combustion chamber ( 3) A swirl burner is installed in a through arrangement at the bottom, a third smoke exhaust channel (8) is provided on the upper part of the inner furnace (6), a first smoke exhaust channel (9) and a second smoke exhaust channel (12) which can be independently controlled to open and close and the opening degree are provided on the upper part of the outer furnace (7), the outlet of the first smoke exhaust channel (9) is connected to the third smoke exhaust channel (8), the outlet of the second smoke exhaust channel (12) is connected to the inlet of the cyclone separator (13), the upper outlet of the cyclone separator (13) is connected to the inlet of the swirl burner through the combustible gas connecting pipe (15), and the lower outlet of the cyclone separator (13) is connected to the combustion chamber (3) of the inner furnace through the residual carbon channel (14).

2. The biomass dual-hearth combustion furnace with bottom-mounted direct current and swirl burners according to claim 1, characterized in that: The inner furnace (6) and the outer furnace (7) adopt a coaxially nested cylindrical partitioned combustion structure.

3. A biomass dual-hearth combustion furnace with bottom-mounted direct current and swirl burners according to claim 1 or 2, characterized in that: Each DC burner comprises a primary air channel (4) and a DC secondary air channel (5), and the DC secondary air channel (5) is coaxially arranged on the periphery of the primary air channel (4).

4. The biomass dual-hearth combustion furnace with bottom-mounted direct current and swirl burners according to claim 3, characterized in that: The included angle between the center line of the primary air channel (4) and the projection of the furnace bottom on the vertical plane is , 30°< <60°.

5. The biomass dual-hearth combustion furnace with bottom-mounted direct current and swirl burners according to claim 4, characterized in that: The angle between the projection line of the center line of the primary air channel (4) on the bottom surface of the furnace and the horizontal center line of the bottom surface of the furnace is , 30°< <60°.

6. A biomass dual-hearth combustion furnace with bottom-mounted straight-flow and swirl burners according to claim 4 or 5, characterized in that: The posture adjustment component (16) includes a mounting ring (16-1) coaxially nested on the outside of the DC secondary air channel (5), two first rotating shafts (16-2) arranged vertically are respectively provided on both side walls of the DC secondary air channel (5), the other ends of the two first rotating shafts (16-2) are rotatably connected to the left and right ends of the mounting ring (16-1), one end of the first rotating shaft (16-2) is mounted with a first driven bevel gear (16-3), the side of the first driven bevel gear (16-3) is provided with a meshing first driving bevel gear (16-4), the first driving bevel gear (16-4) is mounted on the end of the rotating shaft of a first reduction motor (16-5) arranged vertically above, the first reduction motor (16-5) is fixedly connected to the mounting ring (16-1) through a motor support plate (16-6), and the mounting ring (16-1) is fixedly connected to the first reduction motor (16-5) through a motor support plate (16-6). Two second rotating shafts (16-7) arranged vertically are respectively provided at the front and rear ends of the mounting ring (16-1). The other ends of the two second rotating shafts (16-7) are rotatably connected to the lower parts of two channel connecting plates (16-8) arranged vertically opposite to each other. The upper parts of the two channel connecting plates (16-8) are fixedly connected to the outer wall of the inner furnace (6) and the inner wall of the outer furnace (7). A second driven bevel gear (16-9) is installed at the end of one of the second rotating shafts (16-7). A second driving bevel gear (16-10) meshing with the second driven bevel gear (16-9) is provided on the side of the second driven bevel gear (16-9). The second driving bevel gear (16-10) is installed on the end of the rotating shaft of a second reduction motor (16-11) arranged vertically above. The second reduction motor (16-11) is installed on the channel connecting plate (16-8).

7. The biomass dual-hearth combustion furnace with bottom-mounted direct current and swirl burners according to claim 6, characterized in that: The swirl burner comprises a combustible gas channel (1) and a swirl secondary air channel (2). The swirl secondary air channel (2) is coaxially arranged on the periphery of the combustible gas channel (1), and a plurality of axial swirl blades uniformly arranged along the circumferential direction are provided in the swirl secondary air channel (2).

8. The biomass dual-hearth combustion furnace with bottom-mounted direct current and swirl burners according to claim 7, characterized in that: An air supply inlet is provided at the end of the carbon residue channel (14), and the air supply inlet is connected to an external air supply source.

9. The biomass dual-hearth combustion furnace with bottom-mounted direct current and swirl burners according to claim 8, characterized in that: The biomass double-hearth combustion furnace further comprises a first valve (10) and a second valve (11), wherein the first valve (10) and the second valve (11) are respectively installed in the first smoke exhaust channel (9) and the second smoke exhaust channel (12).

10. The biomass dual-hearth combustion furnace with bottom-mounted straight-flow and swirl burners according to claim 9, characterized in that: The first valve (10) and the second valve (11) are pneumatic or electric regulating valves.

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