Low-load stable-combustion combustion device of tangential combustion boiler

Abstract

The utility model discloses a low-load stable-combustion combustion device of a tangential combustion boiler, which belongs to the technical field of tangential combustion boilers and comprises an over fire air assembly, a combustor assembly and a peak regulation combustor assembly which are sequentially arranged on the tangential combustion boiler from top to bottom. The peak regulation combustor assembly is used for forming large imaginary circle combustion airflow in the boiler; the combustor assembly is used for forming small imaginary circle combustion airflow in the boiler. The over fire air assembly is used for providing additional oxygen, and it is ensured that combustible materials in the boiler are completely combusted. The low-load stable-combustion combustion device of the tangential combustion boiler can effectively solve the problems that in the deep peak regulation process of the tangential combustion boiler in the prior art, the temperature of a hearth is lowered, pulverized coal is difficult to ignite, flame stability is poor, flameout is prone to occurring, and major accident potential of fire extinguishing of the hearth exists.

Description

Technical Field

[0001] This utility model belongs to the technical field of tangential combustion boilers. Specifically, it relates to a low-load stable combustion device for tangential combustion boilers. Background Technology

[0002] In recent years, in accordance with national policy requirements, thermal power units have needed to meet the demands of deep peak shaving in the power grid. Currently, most tangentially fired boilers, without oil or plasma-assisted combustion, typically have a minimum stable combustion load of 35% of their rated load, making it difficult to achieve deep peak shaving below 35% or even lower. During deep peak shaving, the furnace temperature drops, pulverized coal ignition becomes difficult, flame stability is poor, and flameout is likely, posing a significant safety hazard. Stable combustion at low loads is crucial for deep peak shaving in thermal power units, and improving the stable combustion capability of tangentially fired boilers is an important task that needs to be addressed for deep peak shaving. Utility Model Content

[0003] The purpose of this utility model is to provide a low-load stable combustion device for tangential combustion boilers, addressing the aforementioned shortcomings. This device solves the problems of furnace temperature drop, difficulty in igniting pulverized coal, poor flame stability, easy flameout, and significant accident hazards associated with furnace flameout during deep peak shaving in existing tangential combustion boilers. To achieve the above objective, this utility model provides the following technical solution:

[0004] A low-load stable combustion device for a tangential combustion boiler includes a burnout air assembly, a burner assembly, and a peak-shaving burner assembly arranged sequentially from top to bottom on the tangential combustion boiler. The peak-shaving burner assembly is used to form a large imaginary circular combustion airflow in the boiler. The burner assembly is used to form a small imaginary circular combustion airflow in the boiler. The burnout air assembly is used to provide additional oxygen to ensure complete combustion of combustibles in the boiler.

[0005] Furthermore, the peak-shaving burner assembly includes four swirl burners, which are respectively installed on the water-cooled walls on the four sides of the boiler; the four swirl burners simultaneously spray combustion gas to form a large imaginary circular combustion gas flow inside the boiler.

[0006] Furthermore, the distance H between the swirl burner and the adjacent water-cooled wall is not less than 1 / 4L, where L is the width of the water-cooled wall.

[0007] Furthermore, the burner assembly includes several layers of combustion assemblies; each layer of the combustion assembly includes four DC burners; the four DC burners are respectively arranged at the four corners of the boiler; the four DC burners simultaneously inject combustion gas flow to form small imaginary circular combustion gas flow within the boiler.

[0008] Furthermore, the burner assembly includes nine layers of combustion components, configured as four layers of primary air nozzles and five layers of secondary air nozzles, with the primary and secondary air nozzles arranged alternately from top to bottom at the four corners of the boiler.

[0009] Furthermore, the diameter of the large imaginary circular combustion airflow formed by the four swirl burners in the boiler is greater than the diameter of the small imaginary circular combustion airflow formed by the four direct-flow burners in the boiler, and the large imaginary circular combustion airflow and the small imaginary circular combustion airflow are in the same direction, and are either clockwise or counterclockwise.

[0010] Furthermore, the swirl burner includes a central air duct, a pulverized coal primary air duct, an inner secondary air duct, an outer secondary air duct, and a pre-combustion chamber; the pulverized coal primary air duct, the inner secondary air duct, and the outer secondary air duct are all annular channels, arranged concentrically with the central air duct; the pre-combustion chamber is located inside the boiler and is connected to the outlets of the central air duct, the pulverized coal primary air duct, the inner secondary air duct, and the outer secondary air duct.

[0011] Furthermore, both the central air duct and the primary air duct for pulverized coal flow contain direct current airflow; both the inner and outer secondary air ducts are equipped with cyclones with adjustable swirl intensity, forming swirling airflow within the inner and outer secondary air ducts.

[0012] Furthermore, the angle between the swirl burner and the water-cooled wall is α; the value of α ranges from 80 to 100°.

[0013] Furthermore, the burnout air assembly includes a three-layer burner assembly; each layer of the burner assembly includes four DC burners, which are respectively located at the four corners of the boiler.

[0014] The beneficial effects of this utility model are:

[0015] 1. This utility model combines a swirl burner and a direct-flow burner, with the swirl burner arranged on the water-cooled walls on all four sides of the boiler, creating a large imaginary circular combustion airflow within the boiler. The direct-flow burners are arranged at the four corners of the boiler, creating a small imaginary circular combustion airflow with a smaller diameter than the large imaginary circular combustion airflow. Utilizing the stable combustion characteristics of the swirl burner, high-temperature flue gas is generated. This high-temperature flue gas envelops the small imaginary circular combustion airflow formed by the direct-flow burner, creating a combustion pattern where a large high-temperature flame envelops a small flame, thus increasing the stable combustion capability.

[0016] 2. The swirl burner of this utility model is an annular swirl burner with a pre-combustion chamber structure. The stable combustion capability of this burner is further enhanced compared with the tangential direct current burner, which is more conducive to improving the stable combustion capability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model;

[0018] Figure 2 yes Figure 1 BB cross-section diagram;

[0019] Figure 3 yes Figure 1 CC section view;

[0020] Figure 4 This is a schematic diagram of the imaginary circular combustion airflow formed by the swirl burner and the water-cooled wall at another angle.

[0021] Figure 5 This is a schematic diagram of the swirl burner structure of this utility model;

[0022] In the attached diagram: 1. Burnout air assembly; 2. Burner assembly; 3. Swirl burner; 4. Water-cooled wall; 5. DC burner; 6. Primary air nozzle; 7. Secondary air nozzle; 8. Central air duct; 9. Primary air duct; 10. Inner secondary air duct; 11. Outer secondary air duct; 12. Pre-combustion chamber. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0024] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, the terms "horizontal," "vertical," etc., do not indicate that the component is required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0025] Example:

[0026] See attached Figures 1-5A low-load stable combustion device for a tangential combustion boiler includes a burnout air assembly 1, a burner assembly 2, and a peak-shaving burner assembly, arranged sequentially from top to bottom on the boiler. The peak-shaving burner assembly is further arranged according to the number of coal mills, with one coal mill corresponding to one layer of peak-shaving burner assembly. Specifically, the peak-shaving burner assembly includes four swirl burners 3, which are respectively installed on the four side walls of the boiler, with the four swirl burners 3 on the same horizontal line. Compared with the direct-flow burner 5, the swirl burner 3 has a stronger self-stabilizing combustion capability by using swirl air distribution and other methods. Above the swirl burner 3, the burner assembly 2 is arranged, which consists of several layers of combustion assemblies, preferably nine layers. Each layer of combustion assembly includes four direct-flow burners 5, which are preferably installed at the four corners of the boiler, simultaneously injecting combustion gas into the furnace. Above the burner assembly 2 is a burnout air assembly 1, which is also composed of DC burners 5. Preferably, three layers are arranged, with four DC burners 5 in each layer located at the four corners of the boiler. This is used to provide the required oxygen during the burnout stage, ensuring that the fuel can burn completely and reducing the generation of nitrogen oxides during combustion, thereby reducing environmental pollution. The burnout air also helps to stabilize the combustion process and ignite the fuel. The use of the burnout air can be controlled as needed.

[0027] Four swirl burners 3 are located on the four side walls of the boiler, simultaneously injecting combustion gas into the boiler, forming a large imaginary tangential combustion flow inside the boiler, as shown in the attached diagram. Figure 2 As shown; the four DC burners 5 of each combustion assembly are located at the four corners of the boiler, simultaneously injecting combustion airflow into the boiler, forming a small imaginary tangential circle combustion flow with a diameter smaller than the large imaginary tangential circle inside the boiler, as shown in the attached figure. Figure 3 As shown, the imaginary tangent circle of the swirl burner 3 is larger than that of the direct-flow burner 5. The swirl burner 3 has a stronger self-stabilizing combustion capability. Utilizing the stable combustion characteristics of the swirl burner 3, high-temperature flue gas is formed. This high-temperature flue gas envelops the combustion flame generated by the direct-flow burner 5, forming a combustion pattern where a large high-temperature flame envelops a small flame, thus increasing the stable combustion capability. The large imaginary tangent circle formed by the swirl burner 3 and the small imaginary tangent circle formed by the direct-flow burner 5 are in the same direction, either clockwise or counterclockwise.

[0028] Each layer of the nine-layer combustion assembly, consisting of a direct-flow burner 5, is divided into primary air nozzles 6 and secondary air nozzles 7, arranged in an alternating pattern. The fourth layer contains primary air nozzles 6, and the fifth layer contains secondary air nozzles 7. This alternating arrangement of primary and secondary air nozzles 7 allows for better mixing of pulverized coal and air, improving combustion efficiency. Simultaneously, this arrangement helps to form a stable flame, preventing flame deviation or extinguishing, thus ensuring the safe and stable operation of the boiler. Furthermore, by adjusting parameters such as the air volume, velocity, and nozzle angle of the primary and secondary air, the combustion process can be further optimized, pollutant emissions reduced, and the overall performance of the boiler improved.

[0029] The angle between the nozzle direction of the swirl burner 3 and the side wall is α, and the value of α ranges from 80 to 100°. The position of the swirl burner 3 on the side wall of the boiler is arranged according to the specific situation, thereby changing the diameter of the large imaginary tangent circle inside the boiler. This ensures that the diameter of the imaginary tangent circle formed by the swirl burner 3 is always larger than the imaginary tangent circle formed by the direct current burner 5, so as to achieve a combustion mode in which a large flame surrounds a small flame and increase the stable combustion capability.

[0030] The four side walls of the boiler are the water-cooled wall walls 4 of the boiler. The distance L from the position of the swirl burner 3 to the adjacent water-cooled wall wall 4 is not less than 1 / 4L, where L is the width of the water-cooled wall wall 4, in order to prevent the swirling flame of the swirl burner 3 from scouring the water-cooled wall wall 4.

[0031] The swirl burner 3 is preferably equipped with a pre-combustion chamber 12, which includes a central air channel 8, a primary air channel 9 for pulverized coal flow, an inner secondary air channel 10, an outer secondary air channel 11, and a pre-combustion chamber 12. The primary air channel 9, the inner secondary air channel 10, and the outer secondary air channel 11 are all annular channels, arranged concentrically with the central air channel 8. The central and primary air flows are direct current, while the inner and outer secondary air flows are swirling air. Each channel is equipped with a swirler with adjustable swirling intensity. This burner further enhances the stable combustion capability compared to the tangential direct current burner 5, and is more conducive to improving the stable combustion capability of tangential combustion at the four corners.

[0032] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural or procedural transformations made based on the content of the present utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present utility model.

Claims

1. A tangentially fired boiler low load flame stabilization burner characterized by: The application relates to a boiler, which comprises, from top to bottom, a combustion air assembly (1), a burner assembly (2) and a peak-shaving burner assembly arranged on a tangential firing boiler; the peak-shaving burner assembly is used for forming a large imaginary circle combustion gas flow in the boiler; the burner assembly (2) is used for forming a small imaginary circle combustion gas flow in the boiler; and the combustion air assembly (1) is used for providing additional oxygen to ensure complete combustion of combustibles in the boiler.

2. A tangentially fired boiler low load flame stabilization burner according to claim 1, characterized in that: The peak-shaving burner assembly comprises four swirl burners (3) arranged on four water-cooled wall walls (4) of the boiler respectively; the four swirl burners (3) simultaneously inject combustion gas flows to form a large imaginary circle combustion gas flow in the boiler.

3. A tangentially fired boiler low load flame stabilization burner according to claim 2, characterized in that: The distance H between the swirl burner (3) and the adjacent proximal water-cooled wall (4) is not less than 1 / 4L, wherein L is the width of the water-cooled wall (4).

4. A tangentially fired boiler low load flame stabilization burner according to claim 3, characterized in that: The burner assembly (2) comprises a plurality of layers of combustion assemblies; each layer of the combustion assembly comprises four straight-flow burners (5); the four straight-flow burners (5) are arranged at four corners of the boiler respectively; and the four straight-flow burners (5) simultaneously inject combustion gas flows to form a small imaginary circle combustion gas flow in the boiler.

5. A tangentially fired boiler low load flame stabilization burner according to claim 4, characterized in that: The burner assembly (2) comprises nine layers of combustion assemblies, which are arranged as four layers of primary air nozzles (6) and five layers of secondary air nozzles (7); the primary air nozzles (6) and the secondary air nozzles (7) are arranged in a staggered mode from top to bottom at the four corners of the boiler.

6. A tangentially fired boiler low load flame stabilization burner according to claim 5, characterized in that: The diameter of the large imaginary circle combustion gas flow formed by the four swirl burners (3) in the boiler is greater than that of the small imaginary circle combustion gas flow formed by the four straight-flow burners (5) in the boiler, and the directions of the large imaginary circle combustion gas flow and the small imaginary circle combustion gas flow are consistent, being clockwise or counterclockwise.

7. A tangentially fired boiler low load flame stabilization burner according to claim 6, characterized in that: The swirl burner (3) comprises a central air passage (8), a pulverized coal gas flow primary air passage (9), an inner secondary air passage (10), an outer secondary air passage (11) and a precombustion chamber (12); the pulverized coal gas flow primary air passage (9), the inner secondary air passage (10) and the outer secondary air passage (11) are annular passages arranged in a same center with the central air passage (8); and the precombustion chamber (12) is arranged in the boiler and connected with the outlets of the central air passage (8), the pulverized coal gas flow primary air passage (9), the inner secondary air passage (10) and the outer secondary air passage (11).

8. A tangentially fired boiler low load flame stabilization burner according to claim 7, characterized in that: Straight-flow gas flows are formed in the central air passage (8) and the pulverized coal gas flow primary air passage (9); and swirl gas flows are formed in the inner secondary air passage (10) and the outer secondary air passage (11) through swirlers with adjustable swirl intensities.

9. A tangentially fired boiler low load flame stabilization burner according to claim 8, characterized in that: The angle between the swirl burner (3) and the water-cooled wall (4) is alpha; and the value range of alpha is 80-100 degrees.

10. A tangentially fired boiler low load flame stabilization burner according to claim 9, characterized in that: The combustion air assembly (1) comprises three layers of burner assemblies (2); each layer of the burner assembly (2) comprises four straight-flow burners (5) arranged at four corners of the boiler respectively.

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