Air distribution system for preventing high temperature corrosion in coal-fired furnace

Abstract

The present application relates to the technical fields of energy saving and environmental protection, in particular to a kind of air distribution system for preventing high temperature corrosion of pulverized coal furnace, including pulverized coal furnace and two for igniting pulverized coal combustor located in the outer wall of the rear end of pulverized coal furnace, the middle part of the rear end of pulverized coal furnace is equipped with a primary air system for passing into the combustion chamber into pulverized coal, the rear end of pulverized coal furnace is equipped with a plurality of annular regular distribution for supplementing combustion oxygen secondary air system.The air distribution system, by primary air system, secondary air system cooperation can adjust the ratio of primary air and secondary air into the combustion chamber, avoid the imbalance of the ratio of pulverized coal and oxygen leading to insufficient combustion, and then make the high temperature corrosion of water cooled wall in the pulverized coal furnace;At the same time, the secondary air system can adjust the airflow direction of secondary air, strengthen the airflow disturbance in the combustion chamber, so that the pulverized coal in the primary air can be more fully mixed with the oxygen of secondary air, thereby reducing the high temperature corrosion of water cooled wall in the combustion chamber of pulverized coal furnace.

Description

Technical Field

[0001] This invention belongs to the field of energy conservation and environmental protection technology, specifically an air distribution system for pulverized coal boilers to prevent high-temperature corrosion. Background Technology

[0002] A pulverized coal boiler is a type of boiler that uses pulverized coal as fuel. To ensure safety during use, pulverized coal and a certain concentration of oxygen are typically introduced into the combustion chamber via primary and secondary air. Water-cooled walls are installed inside the furnace. However, when the pulverized coal is not completely burned, a large amount of reducing gas accumulates inside the furnace, which can easily corrode the water-cooled walls under high-temperature conditions.

[0003] For example, the waste incineration technology field patent CN114508756A discloses an air preheating and distribution system for an incinerator, including: a blower, an air preheating component, and an air distribution pipeline. The air inlet of the air preheating component is connected to the blower, and the air outlet of the air preheating component is connected to the air distribution pipeline. The air distribution pipeline is connected to a primary combustion chamber via a first branch pipe and to a secondary combustion chamber via a second branch pipe. During incineration, external air is introduced into the air preheating component through the blower. The air preheating component exchanges heat with the high-temperature flue gas in the secondary combustion chamber to deliver the preheated air to the air distribution pipeline, thereby increasing the air temperature entering the primary and secondary combustion chambers.

[0004] Currently, the air distribution system of pulverized coal boilers can only adjust the primary and secondary air velocities, and the secondary air is generally directly mixed with pulverized coal, resulting in poor mixing. During combustion, the pulverized coal is not fully burned, and the internal reducing gases increase, which can easily corrode the water-cooled walls under high-temperature conditions. In order to solve the problems of the above-mentioned air distribution system being able to only adjust the air velocity and the poor mixing effect of secondary air with pulverized coal, which easily corrodes the water-cooled walls, we propose an air distribution system for pulverized coal boilers to prevent high-temperature corrosion.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide an air distribution system for pulverized coal boilers to prevent high-temperature corrosion, thereby solving the aforementioned problems in the prior art.

[0007] To achieve the above objectives, the present invention provides an air distribution system for preventing high-temperature corrosion of a pulverized coal boiler, comprising a pulverized coal boiler and two burners located on the outer side of the rear end of the pulverized coal boiler for igniting pulverized coal. The middle of the rear end of the pulverized coal boiler is provided with a primary air system for introducing pulverized coal into the combustion chamber, and the rear end of the pulverized coal boiler is provided with several secondary air systems arranged in a regular ring for supplementing combustion oxygen.

[0008] The secondary air system includes an external air duct connected to a blower located outside the rear end of the pulverized coal boiler, an internal air duct located inside the pulverized coal boiler, and a secondary air regulating component located at the front end of the external air duct for adjusting the secondary air intake effect. The secondary air regulating component consists of an opening and closing mechanism for controlling the air intake volume and a rotating mechanism for adjusting the opening and closing mechanism. The rotating mechanism includes a rotating plate, several radial grooves on the rotating plate, and air holes in the middle of the rotating plate to facilitate the entry and exit of secondary air. The opening and closing mechanism is located in front of the rotating mechanism and includes several regularly arranged movable plates, a slider located in the middle of the outer edge of the front side wall of the movable plate, and a radial sliding rod located in the middle of the outer edge of the rear side wall of the movable plate. A drive component for driving the rotating plate to rotate is provided at the corresponding position on the outer side wall of the rear end of the pulverized coal boiler.

[0009] The inner wall of the front end of the external air duct is provided with several sliding grooves corresponding to the position of the movable plate. The slider is set in the corresponding sliding groove and the two are slidably connected. The front side wall of the rotating plate is provided with several regularly distributed connecting rods near the outer periphery. The connecting rods pass through the front end face of the external air duct and are fixedly connected to the rear side wall of the inner air duct.

[0010] In the technical solution of the present invention, the primary air system includes a primary air duct located on the outer side wall of the rear end of the pulverized coal furnace and connected to an external coal mill, and an air hood located on the rear side wall inside the pulverized coal furnace and connected to the front end of the primary air duct. The air hood is provided with a plurality of horizontally arranged air direction plates, the front side of the air direction plates is inclined upward, and the burner is symmetrically arranged on the left and right sides above the primary air duct with the flame nozzle facing downward.

[0011] In the technical solution of the present invention, the inner air duct includes a bent pipe and a guide pipe whose rear end is connected to the corresponding outer air duct. A plurality of the bent pipes are arranged at a clockwise inclination, and a plurality of the guide pipes are arranged in a clockwise direction.

[0012] In the technical solution of the present invention, the front end of the external air duct is provided with an air outlet in the middle to facilitate the passage of secondary air. The air outlet is connected to the corresponding inside of the bent pipe. The front end of the external air duct is provided with a plurality of annularly distributed arc-shaped swirl grooves near the periphery. The width of the swirl grooves is adapted to the diameter of the connecting rod. The outer diameter of the bent pipe is equal to the outer diameter of the external air duct, and the inner diameter of the bent pipe is equal to the inner diameter of the air outlet.

[0013] In the technical solution of the present invention, the diameter of the rotating plate is larger than the inner diameter of the external air duct, a limiting ring is fixedly connected to the outer edge of the rotating plate, the limiting ring is embedded in the inner wall of the external air duct, and the rotating plate is rotatable.

[0014] In the technical solution of the present invention, the radial grooves are distributed in a ring on the rotating plate, the radial grooves are arranged radially along the rotating plate, the radial grooves correspond to the position dimensions of the radial slide rod, and the distance between the rotating plate and the inner wall of the front side of the external air duct is equal to the thickness of the movable plate.

[0015] In the technical solution of the present invention, the movable plate is an equilateral triangular plate, the sliding groove is arranged parallel to the outer edge of the movable plate, the rotating plate has a wind hole in the middle, the diameter of the wind hole is equal to the diameter of the air outlet, and the regular hexagonal area enclosed by the plurality of movable plates is larger than the air outlet area.

[0016] In the technical solution of the present invention, the driving assembly includes a drive motor that provides power for the rotation of the rotating plate, a first rotating rod that is connected to the output end of the drive motor through a first gear set, and a second rotating rod located inside the external air duct that is connected to the first rotating rod through a second gear set. The front end of the second rotating rod is bent and the front end face is fixedly connected to the rear side wall of the rotating plate near the periphery. The horizontal section of the rear section of the second rotating rod is coaxial with the rotating plate.

[0017] In the technical solution of the present invention, the drive motor is fixed to the outer side wall of the rear end of the pulverized coal furnace by bolts and corresponds one-to-one with the secondary air system. The first gear set and the second gear set are both composed of meshing bevel gears. The first rotating rod passes through the external air pipe and is connected to the corresponding second rotating rod for transmission.

[0018] In the technical solution of the present invention, the first rotating rod and the second rotating rod are respectively installed on the outer side wall of the rear end of the pulverized coal furnace and in the outer air duct by setting a support rod. The support rod is composed of a rod body and a rod ring fixed at the outer end of the rod body. The first rotating rod and the second rotating rod are respectively provided with an outwardly extending annular first flange and two second flanges. The first flange and the second flange are respectively embedded in the corresponding rod ring and can rotate freely.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0020] 1. In this invention, by cooperating with the primary air system and the secondary air system, the secondary air intake can be adjusted by adjusting the secondary air adjustment component during the combustion of pulverized coal, thereby changing the ratio of primary air to secondary air. This avoids incomplete combustion caused by an imbalance in the ratio of pulverized coal to oxygen, which in turn leads to high-temperature corrosion of the water-cooled wall inside the pulverized coal furnace.

[0021] 2. In this invention, the secondary air system can simultaneously adjust the airflow direction of the secondary air when adjusting the air intake, thereby enhancing the airflow disturbance in the combustion chamber and allowing the pulverized coal in the primary air to mix more fully with the oxygen in the secondary air, thus reducing the high-temperature corrosion of the water-cooled wall in the combustion chamber of the pulverized coal furnace. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 This is a schematic diagram of the rear end of the pulverized coal furnace of the present invention;

[0024] Figure 3 This is a schematic diagram of the rear end of the pulverized coal furnace in this invention from another perspective;

[0025] Figure 4 This is an exploded view of the primary air system in this invention;

[0026] Figure 5 This is an exploded view of the secondary air system in this invention;

[0027] Figure 6 This is an enlarged view of the structure at point A in this invention;

[0028] Figure 7 This is a cross-sectional view of the external air duct in this invention;

[0029] Figure 8 This is an exploded view of the secondary wind regulation structure in this invention;

[0030] Figure 9 This is a schematic diagram of the transfer plate in this invention from another perspective;

[0031] Figure 10 This is a schematic diagram of the driving component in this invention;

[0032] Figure 11 This is an exploded view of the driving component in this invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1. Pulverized coal boiler;

[0035] 2. Primary air system; 21. Primary air duct; 22. Air hood; 23. Air direction indicator;

[0036] 3. Secondary air system; 31. External air duct; 311. Air outlet; 312. Swirl groove; 313. Sliding groove; 32. Internal air duct; 321. Bend pipe; 322. Guide pipe; 33. Secondary air regulating assembly; 331. Rotating mechanism; 3311. Rotating plate; 3312. Limiting ring; 3313. Radial groove; 3314. Air hole; 3315. Connecting rod; 332. Opening and closing mechanism; 3321. Movable plate; 3322. Slider; 3323. Radial slide bar;

[0037] 4. Burner;

[0038] 5. Drive assembly; 51. Drive motor; 52. First gear set; 53. First rotating rod; 531. First flange; 54. Second gear set; 55. Second rotating rod; 551. Second flange; 56. Support rod; 561. Rod body; 562. Rod ring. Detailed Implementation

[0039] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0040] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0041] Reference Figures 1-11 As shown, the present invention provides an air distribution system for preventing high-temperature corrosion of a pulverized coal boiler, comprising a pulverized coal boiler 1 and two burners 4 located on the outer rear wall of the pulverized coal boiler 1 for igniting pulverized coal. A primary air system 2 for introducing pulverized coal into the combustion chamber is provided in the middle of the rear end of the pulverized coal boiler 1. A plurality of secondary air systems 3 arranged in a ring at the rear end of the pulverized coal boiler 1 for supplementing combustion oxygen are provided. By cooperating with the primary air system 2 and the secondary air system 3, the ratio of primary air to secondary air introduced into the combustion chamber can be adjusted, the airflow direction of the secondary air can be adjusted, and the airflow disturbance in the combustion chamber can be strengthened, so that the pulverized coal in the primary air can be more fully mixed with the oxygen in the secondary air, thereby reducing the high-temperature corrosion of the water-cooled wall in the combustion chamber of the pulverized coal boiler 1.

[0042] The secondary air system 3 includes an external air duct 31 connected to a blower located outside the rear end of the pulverized coal boiler 1, an internal air duct 32 located inside the pulverized coal boiler 1, and a secondary air regulating component 33 located at the front end of the external air duct 31 for adjusting the secondary air intake effect. The secondary air regulating component 33 consists of an opening and closing mechanism 332 for controlling the air intake volume and a rotating mechanism 331 for adjusting the opening and closing mechanism 332. The rotating mechanism 331 includes a rotating plate 3311, several radial grooves 3313 located on the rotating plate 3311, and a positioning... The rotating plate 3311 has an air hole 3314 in the middle to facilitate the entry and exit of secondary air. The opening and closing mechanism 332 is located in front of the rotating mechanism 331. The opening and closing mechanism 332 includes several regularly arranged movable plates 3321, a slider 3322 located in the middle of the outer edge of the front side wall of the movable plate 3321, and a radial slide bar 3323 located in the middle of the outer edge of the rear side wall of the movable plate 3321. The outer side wall of the rear end of the pulverized coal furnace 1 is provided with a drive assembly 5 for driving the rotating plate 3311 to rotate at the corresponding position of the secondary air system 3.

[0043] During combustion, in order to coordinate with the primary air, the secondary air intake volume and intake angle are adjusted by the secondary air adjustment component 33 so that the coal powder carried by the primary air can be fully mixed with the oxygen in the secondary air. During adjustment, the drive component 5 drives the rotating plate 3311 to rotate. Since the rotating plate 3311 and the movable plate 3321 are connected by the radial slide rod 3323 and the radial groove 3313, the rotating plate 3311 will drive the movable plate 3321 to slide radially outward. Due to the limiting sliding of the slider 3322 and the sliding groove 313, the movable plate 3321 can only move along the sliding groove 313, which causes the gap between several movable plates 3321 to change, thereby changing the intake volume of the secondary air.

[0044] The inner wall of the front end of the external air duct 31 is provided with several sliding grooves 313 corresponding to the position of the movable plate 3321. The slider 3322 is set in the corresponding sliding groove 313 and the two are slidably connected. The front side wall of the rotating plate 3311 is provided with several regularly distributed connecting rods 3315 near the outer periphery. The connecting rods 3315 pass through the front end face of the external air duct 31 and are fixedly connected to the rear side wall of the inner air duct 32.

[0045] When a large amount of pulverized coal is introduced, in order to ensure complete combustion of the pulverized coal and avoid high-temperature corrosion of the water-cooled wall of the pulverized coal boiler 1 due to incomplete combustion, it is necessary to increase the secondary air intake. At this time, the rotating plate 3311 rotates clockwise, which increases the gap between the movable plates 3321. At the same time, the clockwise rotating plate 3311 drives the inner air duct 32 to rotate through the connecting rod 3315, which reduces the vortex range formed between the inner air ducts 32, making the secondary air more concentrated and the air velocity faster, so as to better mix with the pulverized coal and ensure complete combustion. At the same time, the smaller vortex diameter increases the distance between the combustion area and the water-cooled wall of the pulverized coal boiler 1, which can better mitigate high-temperature corrosion. When less pulverized coal is introduced, in order to avoid introducing too much oxygen, the operation can be reversed to reduce the air intake. At this time, although the vortex diameter formed between the inner air ducts 32 is large and close to the water-cooled wall of the pulverized coal boiler 1, the temperature is not high due to the low oxygen and pulverized coal content, thus reducing the impact of the increased vortex.

[0046] Among them, such as Figures 1-4 As shown, the primary air system 2 includes a primary air duct 21 located on the outer wall of the rear end of the pulverized coal furnace 1 and connected to an external coal mill, and an air hood 22 located on the rear side wall inside the pulverized coal furnace 1 and connected to the front end of the primary air duct 21. The air hood 22 is provided with several horizontally arranged air direction plates 23. The front side of the air direction plates 23 is inclined upward. The burner 4 is symmetrically arranged on the left and right sides above the primary air duct 21 with the flame nozzle facing downward. The air direction plates 23 are fixedly arranged. When the primary air carrying pulverized coal passes through the air direction plates 23, it will be lifted upward, while the burner 4 is downward to better ignite the pulverized coal and ensure complete combustion.

[0047] In addition, such as Figure 3As shown, the inner air duct 32 includes a bent pipe 321 and a guide pipe 322 connected to the corresponding outer air duct 31 at its rear end. Several bent pipes 321 are arranged in a clockwise inclined direction, and several guide pipes 322 are arranged in a clockwise direction. The bent pipes 321 and guide pipes 322 can form a vortex of secondary air entering the combustion chamber, which can not only ensure the stability of the combustion zone, but also increase the wind speed and strengthen the airflow disturbance in the combustion chamber, so that the pulverized coal can be better mixed with the oxygen carried by the secondary air, thereby ensuring complete combustion and reducing high-temperature corrosion.

[0048] Furthermore, such as Figures 5-9 As shown, the front end of the external duct 31 is provided with an air outlet 311 to facilitate the passage of secondary air. The air outlet 311 is connected to the corresponding bend 321. Secondary air can enter the bend 321 through the air outlet 311. The front end of the external duct 31 is provided with several annularly distributed arc-shaped swirl grooves 312. The width of the swirl grooves 312 is adapted to the diameter of the connecting rod 3315. The swirl grooves 312 facilitate the rotation of the connecting rod 3315 by the rotating plate 3311, avoiding obstruction. The outer diameter of the bend 321 is equal to the outer diameter of the external duct 31, and the inner diameter of the bend 321 is equal to the inner diameter of the air outlet 311, ensuring the airtightness between the bend 321 and the external duct 31 and preventing secondary air from escaping from the connection.

[0049] In addition, the diameter of the rotating plate 3311 is larger than the inner diameter of the external air duct 31. A limiting ring 3312 is fixedly connected to the outer edge of the rotating plate 3311. The limiting ring 3312 is embedded in the inner wall of the external air duct 31. The rotating plate 3311 can rotate. The entire outer edge of the rotating plate 3311 is embedded in the external air duct 31 to prevent secondary air from escaping from the connection between the rotating plate 3311 and the external air duct 31.

[0050] Furthermore, the radial grooves 3313 are distributed in a ring on the rotating plate 3311. The radial grooves 3313 are arranged radially along the rotating plate 3311. The radial grooves 3313 correspond to the radial slide rods 3323 in position and size. When the rotating plate 3311 rotates, the radial slide rods 3323 and the radial grooves 3313 cooperate to ensure the stability of the sliding of the movable plate 3321 and avoid the entire system from becoming disordered. The distance between the rotating plate 3311 and the inner wall of the front side of the external air duct 31 is equal to the thickness of the movable plate 3321, preventing the movable plate 3321 from falling off between the rotating plate 3311 and the external air duct 31.

[0051] Specifically, the movable plate 3321 is an equilateral triangular plate, ensuring that the sidewalls of several movable plates 3321 in contact can fit together, avoiding gaps that could cause secondary air to escape. The sliding groove 313 is set parallel to the outer edge of the movable plate 3321, allowing the movable plate 3321 to move parallel along the sliding groove 313, thereby changing the gap in the middle of several movable plates 3321. The rotating plate 3311 has a wind hole 3314 in the middle, the diameter of which is equal to the diameter of the air outlet 311. The regular hexagonal area enclosed by several movable plates 3321 is larger than the area of ​​the air outlet 311, preventing secondary air from escaping from the air outlet 311.

[0052] In addition, such as Figures 10-11 As shown, the drive assembly 5 includes a drive motor 51 that provides power for the rotation of the rotating plate 3311, a first rotating rod 53 that is connected to the output end of the drive motor 51 via a first gear set 52, and a second rotating rod 55 located inside the outer air duct 31 and connected to the first rotating rod 53 via a second gear set 54. The front end of the second rotating rod 55 is bent and its front end face is fixedly connected to the outer periphery of the rear side wall of the rotating plate 3311. The horizontal section of the rear part of the second rotating rod 55 is coaxial with the rotating plate 3311. The drive motor 51 is fixed to the outer rear wall of the pulverized coal furnace 1 by bolts and is connected to the secondary air system 3. In a one-to-one correspondence, the first gear set 52 and the second gear set 54 are both composed of meshing bevel gears. The first rotating rod 53 passes through the external air duct 31 and is connected to the corresponding second rotating rod 55. The drive motor 51 drives the first rotating rod 53 to rotate through the first gear set 52. The first rotating rod 53 drives the second rotating rod 55 to rotate through the second gear set 54. Since the front end of the second rotating rod 55 is fixed to the rear side wall of the rotating plate 3311, it will drive the rotating plate 3311 to rotate. It is worth noting that when adjusting the secondary air, it is only necessary to drive the rotating plate 3311 to rotate 10° to 30°.

[0053] Furthermore, the first rotating rod 53 and the second rotating rod 55 are respectively installed on the outer wall of the rear end of the pulverized coal furnace 1 and inside the external air duct 31 by setting support rods 56. The support rod 56 is composed of a rod body 561 and a rod ring 562 fixed at the outer end of the rod body 561. The first rotating rod 53 and the second rotating rod 55 are respectively provided with an outwardly extending annular first flange 531 and two second flanges 551. The first flange 531 and the second flange 551 are respectively embedded in the corresponding rod rings 562 and can rotate freely. The first rotating rod 53 and the second rotating rod 55 are respectively supported and fixed by the support rods 56. The cooperation of the first flange 531, the second flange 551 and the rod ring 562 can ensure the support limit while not affecting the rotation of the first rotating rod 53 and the second rotating rod 55.

[0054] The working principle of the air distribution system for preventing high-temperature corrosion in the pulverized coal boiler of the present invention is as follows:

[0055] When a large amount of pulverized coal is introduced into the pulverized coal furnace 1, in order to ensure complete combustion of the pulverized coal and avoid incomplete combustion leading to high-temperature corrosion of the water-cooled wall of the pulverized coal furnace 1, it is necessary to increase the intake of secondary air. At this time, the drive motor 51 is started, which drives the first rotating rod 53 to rotate through the first gear set 52. The first rotating rod 53 drives the second rotating rod 55 to rotate through the second gear set 54. Since the front end of the second rotating rod 55 is fixed to the rear side wall of the rotating plate 3311, it will drive the rotating plate 3311 to rotate.

[0056] The clockwise rotation of the rotating plate 3311 increases the gap between the movable plates 3321. At the same time, the clockwise rotation of the rotating plate 3311 drives the inner air duct 32 to rotate through the connecting rod 3315, which reduces the swirl range formed between the inner air ducts 32, making the secondary air more concentrated and the wind speed faster, which can better mix with the pulverized coal to ensure complete combustion. At the same time, the smaller swirl diameter can increase the distance between the combustion zone and the water-cooled wall of the pulverized coal furnace 1, which can better slow down high-temperature corrosion.

[0057] When the amount of pulverized coal introduced is small, in order to avoid introducing too much oxygen, the air intake can be reduced by reversing the operation. At this time, although the diameter of the vortex formed between the inner air ducts 32 is large and close to the water-cooled wall of the pulverized coal furnace 1, the temperature of the combustion zone will not be too high due to the low content of oxygen and pulverized coal, which can reduce the impact of the increased vortex.

[0058] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A pulverized coal boiler air distribution system for preventing high-temperature corrosion, comprising a pulverized coal boiler (1) and two burners (4) located on the outer rear wall of the pulverized coal boiler (1) for igniting pulverized coal, characterized in that: The pulverized coal furnace (1) is provided with a primary air system (2) for introducing pulverized coal into the combustion chamber at the middle of the rear end, and a number of secondary air systems (3) for supplementing combustion oxygen are provided at the rear end of the pulverized coal furnace (1) in a regular ring distribution. The secondary air system (3) includes an external air duct (31) connected to a blower located outside the rear end of the pulverized coal boiler (1), an internal air duct (32) located inside the pulverized coal boiler (1), and a secondary air regulating component (33) located at the front end of the external air duct (31) for adjusting the secondary air intake effect. The secondary air regulating component (33) consists of an opening and closing mechanism (332) for controlling the air intake volume and a rotating mechanism (331) for adjusting the opening and closing mechanism (332). The rotating mechanism (331) includes a rotating plate (3311), several radial grooves (3313) located on the rotating plate (3311), and a positioning groove. The rotating plate (3311) has an air hole (3314) in the middle to facilitate the entry and exit of secondary air. The opening and closing mechanism (332) is located in front of the rotating mechanism (331). The opening and closing mechanism (332) includes several regularly arranged movable plates (3321), a slider (3322) located in the middle of the outer edge of the front side wall of the movable plate (3321), and a radial slide bar (3323) located in the middle of the outer edge of the rear side wall of the movable plate (3321). The outer side wall of the rear end of the pulverized coal furnace (1) and the secondary air system (3) are provided with a drive assembly (5) for driving the rotating plate (3311) to rotate. The inner wall of the front end of the external air duct (31) is provided with a plurality of sliding grooves (313) corresponding to the position of the movable plate (3321). The slider (3322) is set in the corresponding sliding groove (313) and the two are slidably connected. The front side wall of the rotating plate (3311) is provided with a plurality of regularly distributed connecting rods (3315) near the outer periphery. The connecting rods (3315) pass through the front end face of the external air duct (31) and are fixedly connected to the rear side wall of the inner air duct (32). The inner duct (32) includes a bent pipe (321) and a guide pipe (322) that are connected to the corresponding outer duct (31) at the rear end. A plurality of the bent pipes (321) are arranged in a clockwise direction, and a plurality of the guide pipes (322) are arranged in a clockwise direction. The front end of the external air duct (31) is provided with an air outlet (311) to facilitate the passage of secondary air. The air outlet (311) is connected to the corresponding bent pipe (321). The front end of the external air duct (31) is provided with several annularly distributed arc-shaped swirl grooves (312) near the periphery. The width of the swirl grooves (312) is adapted to the diameter of the connecting rod (3315). The outer diameter of the bent pipe (321) is equal to the outer diameter of the external air duct (31), and the inner diameter of the bent pipe (321) is equal to the inner diameter of the air outlet (311).

2. The air distribution system for preventing high-temperature corrosion in a pulverized coal boiler as described in claim 1, characterized in that: The primary air system (2) includes a primary air duct (21) located on the outer side wall of the rear end of the pulverized coal boiler (1) and connected to an external coal mill, and a wind hood (22) located on the rear side wall of the pulverized coal boiler (1) and connected to the front end of the primary air duct (21). The wind hood (22) is provided with several horizontally arranged wind direction plates (23). The front side of the wind direction plates (23) is inclined upward. The burner (4) is located symmetrically arranged on the left and right sides above the primary air duct (21) and the flame nozzle is arranged downward.

3. The air distribution system for preventing high-temperature corrosion in a pulverized coal boiler as described in claim 1, characterized in that: The diameter of the rotating plate (3311) is larger than the inner diameter of the external air duct (31). A limiting ring (3312) is fixedly connected to the outer edge of the rotating plate (3311). The limiting ring (3312) is embedded in the inner wall of the external air duct (31). The rotating plate (3311) is rotatable.

4. The air distribution system for preventing high-temperature corrosion in a pulverized coal boiler as described in claim 1, characterized in that: The radial grooves (3313) are distributed in a ring on the rotating plate (3311). The radial grooves (3313) are arranged radially along the rotating plate (3311). The radial grooves (3313) correspond to the radial slide rod (3323) in position and size. The distance between the rotating plate (3311) and the inner wall of the front side of the external air duct (31) is equal to the thickness of the movable plate (3321).

5. The air distribution system for preventing high-temperature corrosion in a pulverized coal boiler as described in claim 4, characterized in that: The movable plate (3321) is an equilateral triangular plate. The sliding groove (313) is arranged parallel to the outer edge of the movable plate (3321). The rotating plate (3311) has a wind hole (3314) in the middle. The diameter of the wind hole (3314) is equal to the diameter of the air outlet (311). The regular hexagonal area enclosed by several movable plates (3321) is larger than the area of ​​the air outlet (311).

6. The air distribution system for preventing high-temperature corrosion in a pulverized coal boiler as described in claim 1, characterized in that: The drive assembly (5) includes a drive motor (51) that provides power for the rotation of the rotating plate (3311), a first rotating rod (53) that is connected to the output end of the drive motor (51) through a first gear set (52), and a second rotating rod (55) located inside the external air duct (31) and connected to the first rotating rod (53) through a second gear set (54). The front end of the second rotating rod (55) is bent and the front end face is fixedly connected to the rear side wall of the rotating plate (3311) near the periphery. The horizontal section of the rear section of the second rotating rod (55) is coaxial with the rotating plate (3311).

7. The air distribution system for preventing high-temperature corrosion in a pulverized coal boiler as described in claim 6, characterized in that: The drive motor (51) is fixed to the outer wall of the rear end of the pulverized coal furnace (1) by bolts and corresponds one-to-one with the secondary air system (3). The first gear set (52) and the second gear set (54) are both composed of meshing bevel gears. The first rotating rod (53) passes through the external air pipe (31) and is connected to the corresponding second rotating rod (55) for transmission.

8. The air distribution system for preventing high-temperature corrosion in a pulverized coal boiler as described in claim 7, characterized in that: The first rotating rod (53) and the second rotating rod (55) are respectively installed on the outer wall of the rear end of the pulverized coal furnace (1) and the outer air duct (31) by setting a support rod (56). The support rod (56) is composed of a rod body (561) and a rod ring (562) fixed at the outer end of the rod body (561). The first rotating rod (53) and the second rotating rod (55) are respectively provided with an outwardly extending annular first flange (531) and two second flanges (551). The first flange (531) and the second flange (551) are respectively embedded in the corresponding rod ring (562) and can rotate freely.

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