Device for optimizing air distribution performance of over fire air area in thermal power generation

Abstract

The utility model relates to the technical field of boilers, in particular to a device for optimizing the air distribution performance of a thermal power generation over-fire air area, which comprises two secondary air pipes arranged in parallel, two groups of over-fire units are arranged between the two secondary air pipes, and each over-fire unit comprises an over-fire air box and a secondary air box. The two ends of the burnout air bellow and the two ends of the secondary air bellow communicate with the two secondary air pipes, and an air distribution unit is arranged between the burnout air bellow and the secondary air bellow and comprises a main air supply mechanism and a secondary air supply mechanism; the main air supply mechanism comprises a branch pipe and a main pipe, the branch pipe is U-shaped, the input ends of the branch pipe and the secondary air supply mechanism are welded to the two ends of the upper portion of the secondary air bellow, the middle of the branch pipe communicates with the main pipe, the output end of the main pipe is welded to the middle of the burnout air bellow, and the output end of the secondary air supply mechanism communicates to the two ends of the side wall of the burnout air bellow. By implementing the scheme, the air distribution performance of the middle area of the burnout bellows is improved, and stable operation of the boiler is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of boiler technology, specifically to a device for optimizing the air distribution performance in the burnout wind zone of thermal power generation. Background Technology

[0002] In a 660MW thermal power plant, the burnout air box is a crucial component of the combustion system. Its main function is to supply oxygen to the boiler combustion chamber and, based on combustion conditions, adjust the airflow and velocity to promote the continued combustion of incompletely burned fuel particles, thereby improving combustion efficiency. By improving the combustion process, emissions of pollutants such as nitrogen oxides and carbon monoxide are reduced.

[0003] Currently, most burnout air boxes are integrated structures with air intakes on both sides. Multiple burnout air regulators are installed on the side walls of the burnout air box. Because the burnout air box is quite long, approximately 30 meters, the airflow from the regulators near the air inlets is greater than that from the regulators in the middle area. This uneven distribution of burnout air within the furnace during unit operation leads to insufficient airflow in the middle of the burnout air box when the power reaches 550MW or higher, resulting in severe oxygen deficiency in the furnace, increased CO concentration, and a reducing atmosphere, thus reducing combustion efficiency. While adjusting the airflow by regulating the burnout air regulators is common, this has a significant impact on combustion during unit operation, easily causing unstable boiler combustion and potentially leading to boiler shutdown. Furthermore, the components of the burnout air regulators on both sides of the burnout air box are prone to damage from blow-through, posing a safety hazard. After regulator failure, insufficient airflow further reduces oxygen content, resulting in incomplete combustion of fuel particles, leading to increased emissions of pollutants such as nitrogen oxides and carbon monoxide, causing environmental pollution.

[0004] Therefore, in order to solve the above problems and overcome the shortcomings of existing technologies, there is an urgent need for an improved and optimized device for the air distribution performance of the burnout wind area in thermal power generation, which can improve the wind field distribution, enhance air distribution performance, and ensure the safe and stable operation of the boiler. Utility Model Content

[0005] The present invention aims to provide a device for optimizing the air distribution performance in the burnout wind area of ​​thermal power plants. By improving the wind field distribution, the device improves the air distribution performance, thereby solving the problems of equipment damage and unstable boiler operation caused by poor air distribution performance and insufficient oxygen supply.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A device for optimizing the air distribution performance of the burnout wind area in thermal power generation includes two parallel secondary air ducts. Two sets of burnout units are provided between the two secondary air ducts. Each burnout unit includes a burnout air box and a secondary air box. Both ends of the burnout air box and the secondary air box are connected to the two secondary air ducts. An air distribution unit is provided between the burnout air box and the secondary air box. The air distribution unit includes a main air supply mechanism and a secondary air supply mechanism. The main air supply mechanism includes a branch pipe and a main pipe. The branch pipe is U-shaped. The input ends of the branch pipe and the secondary air supply mechanism are welded to both ends of the upper part of the secondary air box. The middle part of the branch pipe is connected to the main pipe. The output end of the main pipe is welded to the middle part of the burnout air box. The output end of the secondary air supply mechanism is connected to both ends of the side wall of the burnout air box.

[0008] The principles and advantages of this scheme are:

[0009] Existing air supply solutions directly supply air to the burnout unit through secondary air ducts. However, due to the excessive length of the burnout air box, insufficient air supply in the central area leads to severe oxygen deficiency in the furnace center, resulting in increased CO concentration and a reducing atmosphere. This reduces combustion efficiency and increases pollutant emissions. This invention addresses this issue by optimizing air supply distribution through an air distribution unit. Air is drawn from the secondary air box and supplied to the central area of ​​the burnout air box. By increasing the air supply to this area, the airflow distribution is effectively improved, resolving the oxygen deficiency combustion problem in the central region, reducing CO concentration, and mitigating equipment damage and boiler instability caused by oxygen deficiency. This not only improves combustion efficiency and prevents the formation of a reducing atmosphere but also alleviates high-temperature corrosion of the water-cooled wall tubes within the furnace area.

[0010] Preferably, as an improvement, pipe compensators are provided on both sides of the middle section of the horizontal section of the branch pipe, and pipe compensators and electric regulating dampers are provided sequentially on the horizontal section of the main pipe and the horizontal section of the secondary air supply mechanism towards the burnout air box.

[0011] Due to the complex environment in which the main and secondary air supply systems operate, pipe compensators are installed to compensate for expansion and contraction caused by factors such as temperature changes, mechanical vibration, and installation errors, thus protecting the pipe system from damage. Electric regulating dampers enable precise control of airflow and optimization of airflow distribution, making the entire air supply system more flexible, enabling rapid response to boiler load changes, maintaining efficient and stable combustion performance, extending equipment lifespan, and reducing maintenance costs. Furthermore, this device further improves energy efficiency while ensuring environmental compliance.

[0012] Preferably, as an improvement, the pipes of both the main air supply mechanism and the secondary air supply mechanism are wrapped with thermal insulation cotton.

[0013] To further optimize combustion, insulation cotton is wrapped around the main and secondary air supply mechanisms. The insulation cotton reduces heat loss, improves combustion efficiency, and thus enhances energy utilization.

[0014] Preferably, as an improvement, the output end of the main pipe is connected to the middle of the top of the burnout bellows.

[0015] After optimization and modeling using professional software, the actual data of the improved device is optimized and the flow field is simulated to obtain complete data. The on-site pipeline installation position is calculated. Taking one side of the air distribution unit as an example, the position of the secondary air supply mechanism does not need to be adjusted. When the output end of the main air supply mechanism is connected to the middle of the top of the first burnout air box, the same applies to the other side. At this time, the overall flow field simulation data is optimal, the air volume is maximized, and the air volume in the middle of the burnout air box is sufficient, thus solving the problem of oxygen deficiency combustion in the middle area of ​​the burnout air box.

[0016] Preferably, as an improvement, the secondary air supply mechanism includes two air supply pipes, which are arranged mirror images of each other on both sides of the main air supply pipe.

[0017] To further enhance the air supply in the central area of ​​the burnout bellows, secondary air supply mechanisms are set up on both sides of the main air supply mechanism as a mirror image, thereby increasing the air supply in the central area and improving the oxygen supply.

[0018] Preferably, as an improvement, the electrically adjustable damper also includes a controller. A CO monitor is provided at the bottom of the secondary air box. The CO monitor is used to detect the concentration of CO and transmit the concentration signal to the controller of the electrically adjustable damper. The controller is used to receive the CO concentration signal and control the opening size of the electrically adjustable damper.

[0019] By precisely coordinating the CO monitor and controller, the opening of the electrically adjustable damper is controlled in real time to ensure sufficient and stable airflow. This keeps the CO concentration within a suitable range, maximizing combustion efficiency, reducing environmental pollution, further optimizing energy allocation, lowering operating costs, and enhancing the overall intelligence of the combustion system. While ensuring high efficiency and energy saving, it also achieves the goals of safety and environmental protection.

[0020] Preferably, as an improvement, the connection between the main air supply mechanism and the secondary air supply mechanism and the secondary air box and the burnout air box is a detachable connection.

[0021] After years of operation, pipelines face the need for replacement and maintenance. Traditional welding methods are not conducive to replacement and maintenance. This solution adopts a detachable connection, which facilitates maintenance and replacement. Furthermore, traditional welding methods have some problems due to insufficient welder skill levels, such as stress concentration caused by thermal expansion and contraction, leading to weld cracks and eventual failure. The detachable connection method can also buffer thermal expansion and contraction caused by temperature changes to a certain extent, ensuring the stability and safety of system operation.

[0022] Preferably, as an improvement, both the main air supply mechanism and the secondary air supply mechanism are equipped with supports and hangers on their horizontal sections.

[0023] Because the main air supply system and the secondary air supply system have long pipelines, supports and hangers are installed on the horizontal sections of both systems to ensure stable operation. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model.

[0025] Figure 2 This is a front view of the overall structure of an embodiment of the present utility model.

[0026] Figure 3 This is a top view of the overall structure of an embodiment of the present utility model.

[0027] Figure 4 This is a left view of the overall structure of an embodiment of the present utility model. Detailed Implementation

[0028] The following detailed description illustrates the specific implementation method:

[0029] The reference numerals in the accompanying drawings include: first burnout air box 1, burnout air regulator 101, first inlet 102, second inlet 103, second burnout air box 2, upper outlet 201, side outlet 202, first and second secondary air boxes 3, second and second secondary air boxes 4, first and second secondary air ducts 5, second and second secondary air ducts 6, main air supply mechanism 7, secondary air supply mechanism 8, duct compensator 9, electric regulating damper 10, and CO monitor 11.

[0030] Example 1 is basically as shown in the attached document. Figure 1-4 As shown:

[0031] As attached Figure 1 As shown, a device for optimizing the air distribution performance of the burnout wind area in thermal power generation includes a first secondary air duct 5 and a second secondary air duct 6 arranged in parallel. Two sets of burnout units are provided between the two secondary air ducts. The left burnout unit includes a first burnout air box 1 and a first secondary air box 3, and the right burnout unit includes a second burnout air box 2 and a second secondary air box 4.

[0032] In this scheme, an air distribution unit is provided between the burnout air box and the secondary air box, and the air distribution unit is set in a mirror symmetrical manner. The following explanation takes the burnout unit on the left as an example.

[0033] The first burnout air box 1 and the first and secondary air boxes 3 are improved by adding an air distribution unit, which includes a main air supply mechanism 7 and a secondary air supply mechanism 8. This directly increases the air intake in the central region of the first burnout air box 1, thereby increasing the oxygen content in the central region and improving combustion efficiency. (See attached diagram) Figure 1 As shown, the first and second secondary air boxes 3 and the first burnout air box 1 are in a parallel state. The left end of the first and second secondary air box 3 is connected to the output end of the first and second secondary air duct 5, and the right end of the first and second secondary air box 3 is connected to the output end of the second and second secondary air duct 6. The left end of the first burnout air box 1 is connected to the upper part near the output end of the first and second secondary air duct 5, and the right end of the first burnout air box 1 is connected to the upper part near the output end of the second and second secondary air duct 6.

[0034] Through flow field simulation calculations, the optimal installation positions and structural forms of the main air supply mechanism 7 and the secondary air supply mechanism 8 were determined, as shown in the attached figure. Figure 1 As shown, the main air supply mechanism 7 consists of branch pipes and a main pipe. The branch pipes are U-shaped, and the main pipe is connected to the middle of the branch pipes. There are two secondary air supply mechanisms. The input ends of the branch pipes and the secondary air supply mechanisms 8 are welded to the upper ends of the first and second air boxes. The output end of the main pipe is welded to the top center of the first burnout air box 1, and the output ends of the two secondary air supply mechanisms 8 are welded to the side walls of the burnout air box. With this structural configuration, the air volume provided by the main air supply mechanism 7 and the secondary air supply mechanism 8 reaches its maximum value, the flow field distribution is most uniform, and the combustion efficiency also reaches its peak. In addition, pipe compensators 9 are installed at 1 / 3 and 2 / 3 of the horizontal section of the branch pipe. Pipe compensators 9 and electric regulating dampers 10 are installed sequentially on the horizontal section of the main pipe and the horizontal section of the secondary air supply mechanism 8 towards the burnout air box. By setting the pipe compensators 9, the expansion and contraction deformation of the pipeline caused by factors such as temperature changes, mechanical vibration, and installation errors is compensated, thereby protecting the pipeline system from damage. By setting up the electrically adjustable damper 10, precise control of air volume and optimization of air field distribution are achieved, enabling the entire air supply system to respond quickly to boiler load changes and maintain efficient and stable combustion performance. The electrically adjustable damper 10 also includes a controller. A CO monitor 11 is provided at the bottom of the first and secondary air boxes 3. The CO monitor 11 is used to detect the CO concentration and transmit the concentration signal to the controller of the electrically adjustable damper 10. The controller is used to receive the CO concentration signal and control the opening size of the electrically adjustable damper 10. The controller can adopt existing control technologies, such as PLC control technology.

[0035] To ensure stable operation of the main air supply mechanism 7 and the secondary air supply mechanism 8, supports and hangers are installed on the horizontal sections of both mechanisms. The pipes of both the main and secondary air supply mechanisms 7 and 8 are wrapped with insulation cotton. This insulation effectively isolates the hot and cold air inside the pipes from heat exchange with the external environment, preventing increased energy consumption due to heat loss or preventing the influence of external heat sources on the cold air, thereby improving combustion efficiency.

[0036] The specific implementation method is as follows:

[0037] Flow field simulation was performed on actual data using software modeling to obtain a complete dataset. Subsequently, the installation locations and pipe diameters of the main air supply unit 7 and the secondary air supply unit 8 were calculated and determined. The arrangement in this embodiment is shown in the attached figure. Figure 1 As shown. The first and second secondary air boxes 3 and the first burnout air box 1 are modified by opening holes to allow the output and input ends of the main air supply mechanism 7 and the secondary air supply mechanism 8 to be welded to the first and second secondary air boxes 3 and the first burnout air box 1, respectively, on site. Next, the compensator, the electrically adjustable damper 10, and the CO monitor 11 are installed. After the equipment is installed, it is debugged. Air enters the first burnout air box 1 and the first and second secondary air boxes 3 from the first and second secondary air ducts 5 and 6, respectively. Some air is directly supplied from the main air supply mechanism 7 and the secondary air supply mechanism 8 to the central area of ​​the first burnout air box 1. The CO monitoring device monitors the concentration signal in real time and adjusts the electrically adjustable damper 10 to control the ventilation volume. After ensuring that everything is operating normally, the equipment can be put into formal use.

[0038] The main air supply mechanism 7 and the secondary air supply mechanism 8 work together, in conjunction with the CO monitor 11, the electrically adjustable damper 10, and the pipeline compensator 9, to form a device that optimizes the air distribution performance in the burnout air area of ​​thermal power plants. During operation, this device dynamically adjusts the airflow by monitoring the CO concentration signal in real time, eliminating the need for airflow adjustment based on the burnout air regulator 101. By optimizing the airflow distribution, it effectively solves the problem of oxygen deficiency combustion in the central area of ​​the burnout air box, significantly reducing the CO concentration. This not only solves the equipment damage and boiler operational instability caused by oxygen deficiency but also improves combustion efficiency, avoids the formation of a reducing atmosphere, alleviates high-temperature corrosion of the water-cooled wall tubes in the furnace, and reduces environmental pollution.

[0039] Example 2 is attached. Figure 1-4 As shown:

[0040] Unlike Embodiment 1, the main air supply mechanism 7 and the secondary air supply mechanism 8 are connected to the first and secondary air boxes 3 and the first burnout air box 1 using flange bolts. Traditional welding methods are inconvenient for replacement and maintenance; this solution uses a detachable connection, facilitating maintenance and replacement. Furthermore, welded connections suffer from insufficient strength due to the limited skill of welders, such as stress concentration caused by thermal expansion and contraction, leading to weld cracks and eventual failure. The detachable connection method also buffers thermal expansion and contraction caused by temperature changes to a certain extent, ensuring the stability and safety of the system operation. Other parts are the same as in Embodiment 1 and will not be repeated here.

[0041] The above descriptions are merely embodiments of this utility model. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A device for optimizing the air distribution performance in the burnout wind area of ​​thermal power plants, characterized in that: It includes two parallel secondary air ducts, with two sets of burnout units between them. Each burnout unit includes a burnout air box and a secondary air box. Both ends of the burnout air box and the secondary air box are connected to the two secondary air ducts. An air distribution unit is provided between the burnout air box and the secondary air box. The air distribution unit includes a main air supply mechanism and a secondary air supply mechanism. The main air supply mechanism includes a branch pipe and a main pipe. The branch pipe is U-shaped. The input ends of the branch pipe and the secondary air supply mechanism are welded to both ends of the upper part of the secondary air box. The middle part of the branch pipe is connected to the main pipe. The output end of the main pipe is welded to the middle part of the burnout air box. The output end of the secondary air supply mechanism is connected to both ends of the side wall of the burnout air box.

2. The device for optimizing the air distribution performance in the burnout wind area of ​​thermal power plants according to claim 1, characterized in that: Pipe compensators are provided on both sides of the middle section of the horizontal section of the branch pipe, and pipe compensators and electric regulating dampers are provided sequentially on the horizontal section of the main pipe and the horizontal section of the secondary air supply mechanism towards the burnout air box.

3. The device for optimizing the air distribution performance in the burnout wind area of ​​thermal power plants according to claim 2, characterized in that: The pipes of both the main air supply mechanism and the secondary air supply mechanism are wrapped with thermal insulation cotton.

4. The device for optimizing the air distribution performance in the burnout wind area of ​​thermal power generation according to claim 3, characterized in that: The output end of the main tube is connected to the middle of the top of the burnout bellows.

5. The device for optimizing the air distribution performance in the burnout wind area of ​​thermal power generation according to claim 4, characterized in that: The secondary air supply system includes two air supply pipes, which are arranged mirror images of the main air supply pipes on both sides.

6. The device for optimizing the air distribution performance in the burnout wind area of ​​thermal power generation according to claim 5, characterized in that: The electrically adjustable damper also includes a controller. A CO monitor is provided at the bottom of the secondary air box. The CO monitor is used to detect the concentration of CO and transmit the concentration signal to the controller of the electrically adjustable damper. The controller is used to receive the CO concentration signal and control the opening size of the electrically adjustable damper.

7. The device for optimizing the air distribution performance in the burnout wind area of ​​thermal power plants according to claim 6, characterized in that: The main air supply mechanism and the secondary air supply mechanism are connected to the secondary air box and the burnout air box in a detachable manner.

8. The device for optimizing the air distribution performance in the burnout wind area of ​​thermal power plants according to claim 7, characterized in that: Both the main air supply mechanism and the secondary air supply mechanism are equipped with supports and hangers on their horizontal sections.

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