A self-adaptive air volume secondary air pipe suitable for multi-load conditions of a CFB boiler

Abstract

The utility model discloses a kind of self-adapting air volume secondary air pipe suitable for CFB boiler multi-load condition, including secondary air pipe, movable air damper, connecting rod, limit ring, air duct mouth baffle, movable air damper is arranged in secondary air pipe;Movable air damper is connected with connecting rod;Connecting rod is passed through limit ring, other end is hinged with air duct mouth baffle through pin shaft;Limit ring is fixedly connected with secondary air pipe inner wall;Air duct mouth baffle is located at the end of air pipe, is fixed in air pipe by spring shaft, air duct mouth baffle can be force around spring shaft rotation open-close;Spring shaft can help its reset.The utility model utilizes air duct mouth baffle, by controlling the cross-sectional dimension at the end of air pipe, effectively guaranteeing that secondary air pipe reaches ideal wind speed under different boiler load conditions.Movable air damper can withstand wind pressure under different air volume, air duct mouth baffle is driven by connecting rod, so that air duct mouth baffle can adjust the cross-sectional dimension of air duct end, so that secondary air port can reach ideal wind speed under different conditions.

Description

Technical Field

[0001] This utility model relates to the field of circulating fluidized bed boiler technology, and in particular to an adaptive air volume secondary air duct suitable for multi-load operating conditions of CFB boilers. Background Technology

[0002] Circulating fluidized bed (CFB) boilers are boilers that employ fluidized bed combustion technology and are widely used in power generation and industrial sectors. Among these, CFB combustion technology is increasingly playing a crucial role due to its unique advantages, including strong fuel adaptability, high stability at low loads, low cost of pollutant control, and wide load adjustment range. Therefore, modifying the traditional structure of CFB boilers to adapt to different load conditions has become key to improving their load adjustment capabilities.

[0003] Under low-load boiler operation, the overall secondary air fluidization volume decreases, while the cross-section of the secondary air duct remains unchanged, resulting in a corresponding decrease in air velocity. This causes the air velocity to fail to reach the ideal value required, making the secondary air duct prone to backflow of flue gas and localized high temperatures. Consequently, this leads to secondary air duct erosion, flue gas leakage, and increased NOx emissions, affecting equipment safety and hindering long-term boiler operation. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model designs an adaptive air volume secondary air duct suitable for CFB boilers under multiple load conditions.

[0005] The present invention adopts the following technical solution: An adaptive airflow secondary air duct suitable for multi-load operation of CFB boilers includes a secondary air duct, a movable damper, a connecting rod, a limiting ring, and an air duct opening baffle. The movable damper is arranged inside the secondary air duct. The movable damper is connected to the connecting rod. The connecting rod passes through the limiting ring, and its other end is hinged to the air duct opening baffle via a pin. The limiting ring is fixedly connected to the inner wall of the secondary air duct. The air duct opening baffle is located at the end of the air duct and is fixed inside the air duct by a spring shaft. The air duct opening baffle can be opened and closed by rotating around the spring shaft under force. The spring shaft can help it return to its original position.

[0006] Preferably, the secondary air duct is arranged in the secondary air system at the point where the secondary air box enters the furnace.

[0007] Preferably, the end of the secondary air duct is angled downwards toward the interior of the furnace.

[0008] Preferably, the limiting ring is welded to the inner wall of the secondary air duct.

[0009] Preferably, the movable damper is located at the axial center of the secondary air duct.

[0010] The beneficial effects of this utility model are as follows: By utilizing the air duct inlet baffle and adjusting the cross-sectional dimensions at the end of the air duct, this utility model effectively ensures that the secondary air duct achieves the ideal wind speed under different boiler load conditions. Air from the secondary air box enters the secondary air duct, passes through the movable air baffle and the air duct inlet baffle, and is then blown into the furnace through the end of the air duct. The movable air baffle can withstand the wind pressure under different air volumes. The air duct inlet baffle is driven by a connecting rod, allowing the cross-sectional dimensions at the end of the air duct to be adjusted, thus ensuring that the secondary air duct achieves the ideal wind speed under different operating conditions. Attached Figure Description

[0011] Figure 1 This is a cross-sectional structural schematic diagram of one embodiment of the present invention.

[0012] Figure 2 This is a structural layout diagram of the present invention in the boiler secondary air system.

[0013] Figure 3 This is a schematic diagram of the operation of this utility model under different load conditions. Figure 1 .

[0014] Figure 4 This is a schematic diagram of the operation of this utility model under different load conditions. Figure 2 .

[0015] In the diagram: 1. Secondary air duct, 2. Movable damper, 3. Connecting rod, 4. Limiting ring, 5. Air duct inlet damper, 6. Spring shaft, 7. Air duct end, 8. Secondary air box, 9. Furnace. Detailed Implementation

[0016] The technical solution of this utility model will be further described in detail below through specific embodiments and with reference to the accompanying drawings: Example: Figure 1 As shown, an adaptive airflow secondary air duct suitable for various load conditions of a CFB boiler includes a secondary air duct 1, a movable damper 2, a connecting rod 3, a limiting ring 4, and an air duct inlet baffle 5. The movable damper 2 is arranged inside the secondary air duct 1; the movable damper 2 is located at the axial center of the secondary air duct and is connected to the connecting rod 3; the connecting rod 3 passes through the limiting ring 4, and its other end is connected to the air duct inlet baffle 5 via a pin; the limiting ring 4 is welded to the inner wall of the secondary air duct 1; the air duct inlet baffle 5 is located at the end 7 of the air duct and is fixed inside the air duct by a spring shaft 6. The air duct inlet baffle 5 can be opened and closed by rotating around the spring shaft 6 under force; the spring shaft 6 helps it to return to its original position.

[0017] When using this embodiment, as follows: Figure 2As shown, the air supplied from the secondary air box 8 enters the secondary air duct 1, passes through the movable air damper 2 and the air duct outlet baffle 5, and is then blown into the furnace 9 through the end of the air duct 7. The movable air damper 2 can withstand the air pressure under different air volumes. The air duct outlet baffle 5 is driven by the connecting rod 3, so that the outlet flow cross-sectional size of the air duct outlet 5 can be adjusted, thereby enabling the secondary air outlet to achieve the ideal air velocity under different operating conditions.

[0018] like Figure 3 and Figure 4 As shown, during maximum load operation, the secondary air impacts the movable damper 2, and the connecting rod 3 drives the duct outlet damper 5 to its maximum opening, resulting in the maximum flow cross-sectional area at the outlet of the duct end 7, at which point the wind speed reaches the ideal wind speed. During low load operation, the secondary air volume is smaller than during normal operation, reducing the air pressure impacting the movable damper 2. The connecting rod 3 drives the duct outlet damper 5 to a smaller opening, reducing the flow cross-sectional area at the outlet of the duct end 7, and the wind speed is closer to the ideal wind speed. When the secondary air is closed, the spring shaft 6 helps the duct outlet damper 5 return to its minimum opening position, preventing flue gas from backflowing into the secondary air duct.

[0019] The embodiments described above are merely preferred solutions of this utility model and are not intended to limit this utility model in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. An adaptive airflow secondary air duct suitable for multi-load operation of CFB boilers, characterized in that, It includes a secondary air duct, a movable air damper, a connecting rod, a limiting ring, and an air duct opening baffle. The movable air damper is arranged inside the secondary air duct. The movable air damper is connected to the connecting rod. The connecting rod passes through the limiting ring, and its other end is hinged to the air duct opening baffle by a pin. The limiting ring is fixedly connected to the inner wall of the secondary air duct. The air duct opening baffle is located at the end of the air duct and is fixed inside the air duct by a spring shaft. The air duct opening baffle can be opened and closed by rotating around the spring shaft under force. The spring shaft can help it return to its original position.

2. The adaptive airflow secondary air duct suitable for multi-load operation of CFB boilers according to claim 1, characterized in that, The secondary air duct is arranged in the secondary air system and is located at the point where the secondary air box enters the furnace.

3. The adaptive airflow secondary air duct suitable for multi-load operation of CFB boilers according to claim 1, characterized in that, The end of the secondary air duct is angled downwards toward the inside of the furnace.

4. The adaptive airflow secondary air duct suitable for multi-load operation of CFB boilers according to claim 1, characterized in that, The limiting ring is welded to the inner wall of the secondary air duct.

5. The adaptive airflow secondary air duct suitable for multi-load operation of CFB boilers according to claim 1, characterized in that, The movable damper is located at the axial center of the secondary air duct.

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