Biomass bubbling fluidized bed boiler with secondary air multi-stage air distribution structure
Patent Information
- Application Number
- CN202522209440.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-20
- Publication Date
- 2026-10-13
- Estimated Expiration
- 2035-10-20
AI Technical Summary
[0004]本实用新型的目的在于提供一种带有二次风多级配风结构的生物质鼓泡流化床锅炉，以解决上述背景技术中提出由于生物质燃料挥发分高、燃点低，在炉膛下部迅速析出和燃烧，而固定碳的燃尽需要较长时间；传统的单点或单层二次风送入方式，无法与燃料的燃烧阶段良好匹配，导致氧气与可燃气体混合不充分，化学不完全燃烧损失大的问题
[0015]本实用新型通过设置上部二次风环管、中部二次风环管和下部二次风环管三层独立的二次风环管及对应的上部二次风喷管、中部二次风喷管和下部二次风喷管，并配合各自独立的第一风量调节阀、第二风量调节阀和第三风量调节阀，实现了精准的多级配风；同时通过设置可转动的上部二次风喷管、中部二次风喷管和下部二次风喷管及其内部的风叶，能够引导气流旋转喷出，在所述锅炉炉膛的中部形成强力的旋流扰动场。这一结构显著增强了二次风与炉内高温烟气和未燃尽燃料的混合效率，确保了挥发分和焦炭颗粒的充分燃尽，从而有效提升了锅炉的整体燃烧效率。并且，由所述第一风量调节阀、第二风量调节阀和第三风量调节阀独立可控的三层配风为炉内创造了理想的分级燃烧条件，有助于抑制氮氧化物的生成，达到节能与环保的双重目的。
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Figure CN224850561U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of biomass energy utilization technology, specifically a biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure. Background Technology
[0002] Biomass energy, as a clean and renewable energy source, plays an important role in energy conservation and emission reduction through its efficient utilization. Bubbling fluidized bed boilers are widely used in biomass combustion power generation and heating due to their advantages such as wide fuel adaptability, stable combustion, and good load regulation performance.
[0003] Because biomass fuel has high volatile content and low ignition point, it is rapidly released and burned in the lower part of the furnace, while the burnout of fixed carbon takes a long time. Traditional single-point or single-layer secondary air supply methods cannot be well matched with the combustion stage of the fuel, resulting in insufficient mixing of oxygen and combustible gas and large losses due to incomplete chemical combustion. To address this, we propose a biomass bubbling fluidized bed boiler with a multi-stage secondary air distribution structure. Utility Model Content
[0004] The purpose of this invention is to provide a biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure, in order to solve the problems mentioned in the background art, which are caused by the high volatile content and low ignition point of biomass fuel, which rapidly precipitates and burns in the lower part of the furnace, while the burnout of fixed carbon requires a long time; the traditional single-point or single-layer secondary air supply method cannot match the combustion stage of the fuel well, resulting in insufficient mixing of oxygen and combustible gas and large losses due to incomplete chemical combustion.
[0005] To achieve the above objectives, this utility model provides the following technical solution: a biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure, comprising:
[0006] The boiler furnace includes an upper secondary air ring pipe fixedly installed in its upper part, with an upper secondary air nozzle movably installed inside the upper secondary air ring pipe; a middle secondary air ring pipe fixedly installed in its middle part, with a middle secondary air nozzle movably installed inside the middle secondary air ring pipe; a lower secondary air ring pipe fixedly installed in its lower part, with a lower secondary air nozzle movably installed inside the lower secondary air ring pipe; a primary air system installed at the bottom of the boiler furnace; a secondary air main pipe installed on the right side of the boiler furnace; a first air volume regulating valve installed between the secondary air main pipe and the upper secondary air ring pipe; a second air volume regulating valve installed between the secondary air main pipe and the middle secondary air ring pipe; and a third air volume regulating valve installed between the secondary air main pipe and the lower secondary air ring pipe.
[0007] In a preferred embodiment of the biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure of this utility model, the secondary air main pipe is connected to the upper secondary air ring pipe through the first air volume regulating valve, the secondary air main pipe is connected to the middle secondary air ring pipe through the second air volume regulating valve, and the secondary air main pipe is connected to the lower secondary air ring pipe through the third air volume regulating valve.
[0008] As a preferred embodiment of the biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure of this utility model, the upper secondary air nozzles are uniformly distributed along the outer surface of the upper secondary air ring pipe, and the axis of the upper secondary air nozzles forms an upward angle of 15° to 45° with the cross-section of the boiler furnace. The middle secondary air nozzles are uniformly distributed along the outer surface of the middle secondary air ring pipe, and the axis of the middle secondary air nozzles forms a horizontal or upward angle of 0° to 15° with the cross-section of the boiler furnace. The lower secondary air nozzles are uniformly distributed along the outer surface of the lower secondary air ring pipe, and the axis of the lower secondary air nozzles forms a downward angle of 10° to 30° with the cross-section of the boiler furnace.
[0009] As a preferred embodiment of the biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure of this utility model, the central secondary air ring pipe is further provided with:
[0010] A fixed pipe is fixedly installed inside the middle secondary air ring pipe, and a connecting bearing is fixedly installed inside the fixed pipe.
[0011] In a preferred embodiment of the biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure of this utility model, the central secondary air nozzle is movably connected to the fixed pipe through the connecting bearing, the central secondary air ring pipe is connected to the fixed pipe, and the fixed pipe is connected to the central secondary air nozzle.
[0012] As a preferred embodiment of the biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure according to this utility model, the central secondary air nozzle is further provided with:
[0013] The fan blade is fixedly installed inside the central secondary air nozzle, which has a bent structure.
[0014] Compared with the prior art, this utility model provides a biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure, which has the following beneficial effects:
[0015] This invention achieves precise multi-stage air distribution by setting up three independent secondary air ring pipes—an upper, middle, and lower secondary air ring pipe—and corresponding upper, middle, and lower secondary air nozzles, along with their respective independent first, second, and third air volume regulating valves. Simultaneously, the rotatable upper, middle, and lower secondary air nozzles and their internal fan blades guide the airflow to rotate and spray out, forming a strong swirling disturbance field in the center of the boiler furnace. This structure significantly enhances the mixing efficiency of secondary air with high-temperature flue gas and unburned fuel, ensuring complete combustion of volatiles and coke particles, thereby effectively improving the overall combustion efficiency of the boiler. Furthermore, the three-layer air distribution, independently controllable by the first, second, and third air volume regulating valves, creates ideal staged combustion conditions within the furnace, helping to suppress the formation of nitrogen oxides and achieving the dual goals of energy saving and environmental protection. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0017] Figure 2 This utility model Figure 1 Enlarged structural diagram at point A in the middle;
[0018] Figure 3 This is a schematic diagram of the connection structure between the fixed pipe and the middle secondary air nozzle of this utility model.
[0019] In the diagram: 1. Boiler furnace; 2. Upper secondary air ring pipe; 3. Middle secondary air ring pipe; 4. Lower secondary air ring pipe; 5. Primary air system; 6. Upper secondary air nozzle; 7. First air volume regulating valve; 8. Secondary air main pipe; 9. Second air volume regulating valve; 10. Third air volume regulating valve; 11. Lower secondary air nozzle; 12. Fixed pipe; 13. Middle secondary air nozzle; 14. Fan blade; 15. Connecting bearing. Detailed Implementation
[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0021] Please see Figure 1-3A biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure includes a boiler furnace 1. An upper secondary air ring pipe 2 is fixedly installed in the upper part of the boiler furnace 1. An upper secondary air nozzle 6 is movably installed inside the upper secondary air ring pipe 2. A middle secondary air ring pipe 3 is fixedly installed in the middle part of the boiler furnace 1. A middle secondary air nozzle 13 is movably installed inside the middle secondary air ring pipe 3. A lower secondary air ring pipe 4 is fixedly installed in the lower part of the boiler furnace 1. A lower secondary air nozzle 11 is movably installed inside the lower secondary air ring pipe 4. A primary air system 5 is installed at the bottom of the boiler furnace 1. A secondary air main pipe 8 is installed on the right side of the boiler furnace 1. A first air volume regulating valve 7 is installed between the secondary air main pipe 8 and the upper secondary air ring pipe 2. A second air volume regulating valve 9 is installed between the secondary air main pipe 8 and the middle secondary air ring pipe 3. A third air volume regulating valve 10 is installed between the secondary air main pipe 8 and the lower secondary air ring pipe 4.
[0022] In this implementation scheme, by setting up three independent secondary air ring pipes—upper secondary air ring pipe 2, middle secondary air ring pipe 3, and lower secondary air ring pipe 4—and corresponding upper secondary air nozzle 6, middle secondary air nozzle 13, and lower secondary air nozzle 11, and cooperating with their respective independent first air volume regulating valve 7, second air volume regulating valve 9, and third air volume regulating valve 10, precise multi-stage air distribution is achieved.
[0023] Furthermore:
[0024] In an optional embodiment, the secondary air main duct 8 is connected to the upper secondary air ring duct 2 through the first air volume regulating valve 7, the secondary air main duct 8 is connected to the middle secondary air ring duct 3 through the second air volume regulating valve 9, and the secondary air main duct 8 is connected to the lower secondary air ring duct 4 through the third air volume regulating valve 10.
[0025] In this implementation plan: The design connects the secondary air main duct 8 to the upper secondary air ring duct 2, the middle secondary air ring duct 3, and the lower secondary air ring duct 4 of the upper, middle, and lower layers respectively through three independent first air volume regulating valves 7, second air volume regulating valves 9, and third air volume regulating valves 10. Its core advantage lies in achieving precise and independent control of the secondary air flow of each layer, enabling operators to flexibly allocate the air supply volume of each area according to the combustion conditions, thereby accurately constructing the required staged combustion atmosphere in the furnace, significantly improving combustion efficiency and effectively suppressing the generation of pollutants.
[0026] Furthermore:
[0027] In an optional embodiment, the upper secondary air nozzles 6 are uniformly distributed along the outer surface of the upper secondary air ring pipe 2, and the axis of the upper secondary air nozzles 6 forms an upward angle of 15° to 45° with the cross-section of the boiler furnace 1. The middle secondary air nozzles 13 are uniformly distributed along the outer surface of the middle secondary air ring pipe 3, and the axis of the middle secondary air nozzles 13 forms a horizontal or upward angle of 0° to 15° with the cross-section of the boiler furnace 1. The lower secondary air nozzles 11 are uniformly distributed along the outer surface of the lower secondary air ring pipe 4, and the axis of the lower secondary air nozzles 11 forms a downward angle of 10° to 30° with the cross-section of the boiler furnace 1.
[0028] In this implementation scheme: the upper secondary air nozzle 6, with its upward-sloping jet, effectively lifts unburned particles, extending their residence time and enabling them to participate in combustion; the middle secondary air nozzle 13, arranged horizontally or slightly inclined, creates strong disturbance in the core combustion zone of the furnace, ensuring thorough gas-solid mixing; the lower secondary air nozzle 11, with its downward-sloping design, serves the dual purpose of suppressing the upward movement of the bed material and supplementing oxygen in the combustion zone. This synergistic layout collectively constructs a tiered combustion environment within the furnace, thereby improving combustion efficiency while achieving low-temperature combustion and pollutant control.
[0029] Furthermore:
[0030] In an optional embodiment, the central secondary air ring duct 3 is further provided with:
[0031] The fixed pipe 12 is fixedly installed inside the middle secondary air ring pipe 3, and the connecting bearing 15 is fixedly installed inside the fixed pipe 12.
[0032] In this implementation scheme, the design of the fixed pipe 12 and the connecting bearing 15 provides a stable and flexible rotational support structure for the core central secondary air nozzle 13. This structure ensures the sealing and stability of the secondary airflow path, avoiding pressure loss; on the other hand, it allows the nozzle to rotate freely under the action of airflow, thereby upgrading the traditional static air supply to a dynamic rotating jet, greatly enhancing the penetration and coverage of the airflow in the center of the furnace, which is the key mechanical basis for forming a highly efficient swirling disturbance field and improving combustion efficiency.
[0033] Furthermore:
[0034] In an optional embodiment, the central secondary air nozzle 13 is movably connected to the fixed pipe 12 via a connecting bearing 15, the central secondary air ring pipe 3 is connected to the fixed pipe 12, and the fixed pipe 12 is connected to the central secondary air nozzle 13.
[0035] In this implementation plan: While ensuring smooth airflow between the central secondary air ring pipe 3, the fixed pipe 12 and the central secondary air nozzle 13, the core advantage of this movable connection structure is that the nozzle can be flexibly rotated through the connecting bearing 15, thereby transforming the static air supply channel into an active disturbance device that can generate a dynamic rotating jet, which greatly enhances the penetration and coverage of the secondary air into the core combustion zone of the furnace, and fundamentally improves the gas-solid mixing efficiency and combustion intensity.
[0036] Furthermore:
[0037] In an optional embodiment, the central secondary air nozzle 13 is further provided with:
[0038] The fan blade 14 is fixedly installed inside the central secondary air nozzle 13, which has a bent structure.
[0039] In this implementation scheme, the central secondary air nozzle 13 of the bent structure is combined with the fan blade 14 fixedly installed inside it. Its core advantage is that when the high-speed airflow passes through, the fan blade 14 is impacted and generates tangential force, while the bent pipe wall has a lever amplification effect on this force. The two work together to efficiently convert the linear kinetic energy of the airflow into mechanical energy that drives the nozzle to rotate, thereby realizing self-rotating air supply without external power. Ultimately, the static secondary air jet is transformed into a dynamic rotating jet with a wider coverage and higher turbulence intensity, which greatly enhances the mixing and combustion process in the central area of the furnace.
[0040] Working Principle: When using this biomass bubbling fluidized bed boiler with a multi-stage secondary air distribution structure, the primary air system 5 first introduces air from the bottom of the furnace, causing the bed material and biomass fuel to form a fluidized state in the lower part of the boiler furnace 1 and complete preliminary combustion. At the same time, the combustion air delivered by the secondary air main duct 8 is precisely delivered into the furnace through a three-stage secondary air distribution system: the lower secondary air ring pipe 4 and the lower secondary air nozzle 11 are injected at a downward angle to supplement oxygen and stabilize the bed material; the upper secondary air ring pipe 2 and the upper secondary air nozzle 6 are injected at an upward angle to ensure complete combustion of unburned components. The central secondary air ring pipe 3 and its internal central secondary air nozzle 13 are movably connected to the fixed pipe 12 via a connecting bearing 15. The unique internal bent structure and fixed fan blades 14 cause the ejected airflow to rotate strongly, creating a highly efficient mixing swirling disturbance zone in the center of the furnace, greatly enhancing gas-solid mixing. Similarly, the upper secondary air nozzle 6 and lower secondary air nozzle 11 rotate with the same structure, causing the airflow to rotate strongly and greatly enhancing gas-solid mixing. By independently adjusting the first airflow regulating valve 7, the second airflow regulating valve 9, and the third airflow regulating valve 10, the system achieves precise staged air distribution. This creates a reducing burnout zone within the furnace that is conducive to suppressing nitrogen oxide generation, while ensuring the complete combustion of volatiles and carbon particles, ultimately achieving synergistic optimization of high-efficiency combustion and low pollutant emissions. The primary air system 5 is existing technology and will not be described in detail here. This is the working principle of the biomass bubbling fluidized bed boiler with a multi-stage secondary air distribution structure.
[0041] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure, characterized in that, include: A boiler furnace (1) has an upper secondary air ring pipe (2) fixedly installed in the upper part of its interior. An upper secondary air nozzle (6) is movably installed inside the upper secondary air ring pipe (2). A middle secondary air ring pipe (3) is fixedly installed in the middle part of its interior. A middle secondary air nozzle (13) is movably installed inside the middle secondary air ring pipe (3). A lower secondary air ring pipe (4) is fixedly installed in the lower part of its interior. The boiler is equipped with a lower secondary air nozzle (11), a primary air system (5) is installed at the bottom of the boiler furnace (1), a secondary air main pipe (8) is installed on the right side of the boiler furnace (1), a first air volume regulating valve (7) is installed between the secondary air main pipe (8) and the upper secondary air ring pipe (2), a second air volume regulating valve (9) is installed between the secondary air main pipe (8) and the middle secondary air ring pipe (3), and a third air volume regulating valve (10) is installed between the secondary air main pipe (8) and the lower secondary air ring pipe (4).
2. A biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure according to claim 1, characterized in that, The secondary air main pipe (8) is connected to the upper secondary air ring pipe (2) through the first air volume regulating valve (7), the secondary air main pipe (8) is connected to the middle secondary air ring pipe (3) through the second air volume regulating valve (9), and the secondary air main pipe (8) is connected to the lower secondary air ring pipe (4) through the third air volume regulating valve (10).
3. A biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure according to claim 1, characterized in that, The upper secondary air nozzle (6) is evenly distributed along the outer surface of the upper secondary air ring pipe (2). The axis of the upper secondary air nozzle (6) forms an upward angle of 15° to 45° with the cross-section of the boiler furnace (1). The middle secondary air nozzle (13) is evenly distributed along the outer surface of the middle secondary air ring pipe (3). The axis of the middle secondary air nozzle (13) forms a horizontal or upward angle of 0° to 15° with the cross-section of the boiler furnace (1). The lower secondary air nozzle (11) is evenly distributed along the outer surface of the lower secondary air ring pipe (4). The axis of the lower secondary air nozzle (11) forms a downward angle of 10° to 30° with the cross-section of the boiler furnace (1).
4. A biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure according to claim 1, characterized in that, The central secondary air ring pipe (3) is also equipped with: A fixed pipe (12) is fixedly installed inside the middle secondary air ring pipe (3), and a connecting bearing (15) is fixedly installed inside the fixed pipe (12).
5. A biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure according to claim 4, characterized in that, The central secondary air nozzle (13) is movably connected to the fixed pipe (12) through the connecting bearing (15), the central secondary air ring pipe (3) is connected to the fixed pipe (12), and the fixed pipe (12) is connected to the central secondary air nozzle (13).
6. A biomass bubbling fluidized bed boiler with a secondary air multi-stage air distribution structure according to claim 1, characterized in that, The central secondary air nozzle (13) is also equipped with: The fan blade (14) is fixedly installed inside the central secondary air nozzle (13), which has a bent structure.