A boiler wall-mounted air system with burners arranged on the front and rear walls

Abstract

This application discloses a boiler wall-mounted air supply system for burners arranged on the front and rear walls, including a secondary air duct structure, side air ducts, air boxes, and connecting air ducts installed on the front and rear walls of the boiler; a group of adjacent air outlets are horizontally opened on the water-cooled wall fins of the boiler side walls; one end of each of the multiple air ducts is connected to the secondary air duct structure, and the other end is connected to the air box; the other end of the air box is connected to the connecting air duct, and the connecting air duct is sequentially connected to the air outlets, for forming an air curtain from front to back on the side walls after air is supplied. This application solves the problem of poor corrosion resistance and poor combustion conditions caused by unreasonable air outlet spacing or arrangement in existing systems by opening adjacent air outlets on the boiler side walls to form an air curtain.

Description

Technical Field

[0001] This application belongs to the field of boiler corrosion prevention technology, and specifically relates to a boiler wall-mounted air supply and system with burners arranged on the front and rear walls. Background Technology

[0002] To reduce the formation of thermal NOx during combustion, staged combustion technology is widely used in existing boilers. After adopting staged combustion technology, the main burner area exhibits a strong reducing atmosphere, and high-temperature corrosion is common in water-cooled walls, becoming increasingly severe with increasing sulfur content in the coal.

[0003] In recent years, boilers with front and rear wall opposed combustion systems have all incorporated wall-mounted air nozzles on their front and rear walls, close to the side wall water-cooled walls and aligned with the main burner. However, this design has not been effective in preventing water-cooled wall corrosion. During retrofitting, one approach is to utilize the original wall-mounted air nozzles, changing the air source from secondary air to high-pressure primary air, which slightly improves corrosion resistance. However, the increased air source pressure leads to a higher proportion of the high-velocity wall-mounted airflow in the total air volume, impacting combustion conditions in the burner area. Another approach is direct side wall air supply. Although this process is slightly more complex, it requires less airflow and provides better corrosion prevention than the wall-mounted air supply on the front and rear walls.

[0004] There are already research results and implementation cases of various types of sidewall air supply. However, the various types of sidewall air supply have gaps between the air outlets or groups of air outlets attached to the wall, which fails to form an air curtain from front to back on the sidewall, thus reducing the anti-corrosion effect. Utility Model Content

[0005] The purpose of this application is to provide a boiler wall-mounted air system with burners arranged on the front and rear walls. This solves the problems mentioned in the background art, such as poor corrosion resistance and poor combustion conditions caused by unreasonable air outlet spacing or arrangement in existing wall-mounted air systems.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] A boiler wall-mounted air system with burners arranged on the front and rear walls includes a secondary air duct structure installed on the front and rear walls of the boiler, air ducts on both sides, air boxes, and connecting air ducts.

[0008] A set of adjacent air vents are opened horizontally on the water-cooled wall fins of the boiler sidewall;

[0009] One end of each of the multiple air ducts is connected to the secondary air duct structure, and the other end is connected to the air box.

[0010] The other end of the bellows is connected to the connecting air duct, which is sequentially connected to the air outlet, so as to form an air curtain from front to back on the side wall after air is supplied.

[0011] In one possible implementation, the air vent is provided in two layers, with the two layers of air vents arranged side by side.

[0012] In one possible implementation, the duct is connected to the secondary air duct structure via an upward connection.

[0013] In one possible implementation, the connecting duct and the air outlet are connected in a downward-sloping manner.

[0014] In one possible implementation, the set of adjacent air outlets are arranged adjacent to each other in the horizontal direction of the sidewall water-cooled wall fins to form an air curtain from front to back.

[0015] In one possible implementation, a sealing gasket is provided between the expansion joint and the connecting duct.

[0016] In one possible implementation, the duct is provided with an adjustment baffle for adjusting the air volume.

[0017] In one possible implementation, an expansion joint is provided on the connecting air duct to compensate for thermal expansion displacement during boiler operation.

[0018] In one possible implementation, the bellows is provided with a hanger, which is mounted on a structural steel beam of the building.

[0019] In one possible implementation, the hanger is configured as a spring structure to buffer the thermal expansion of the boiler's wall-mounted air system.

[0020] Compared with the prior art, this application has the following beneficial effects:

[0021] This application provides a boiler wall-mounted air and system for boilers with burners arranged on the front and rear walls. By opening adjacent air inlets on the side wall water-cooled wall fins of the boiler with burners arranged on the front and rear walls, and using air boxes, connecting air ducts and air pipes to supply air to form an air curtain, the oxygen content in the flue gas attached to the wall is effectively increased, and the content of hydrogen sulfide and carbon monoxide is reduced. This significantly alleviates or avoids the high-temperature corrosion problem of the boiler side wall water-cooled wall, and ensures the long-term safe operation of the boiler.

[0022] In one possible implementation, by horizontally opening adjacent groups of tuyeres on the water-cooled wall fins of the boiler sidewall, an air curtain covering the entire sidewall is formed, which effectively increases the oxygen content of the flue gas adhering to the wall and reduces the concentration of hydrogen sulfide / carbon monoxide, thereby significantly alleviating or eliminating high-temperature corrosion of the water-cooled wall; at the same time, by adopting an air intake structure connected to the secondary air duct above to reduce the amount of ash carried, the system achieves long-term anti-clogging, wear-resistant, and stable operation, ultimately ensuring the safe and economical operation of the boiler and reducing maintenance costs.

[0023] In one possible implementation, a high-temperature resistant sealing gasket is installed between the expansion joint and the flange interface of the connecting air duct. This effectively seals the interface gap caused by manufacturing and installation tolerances and thermal displacement, significantly reduces hot air leakage, ensures stable air volume and pressure leading to the air outlet, maintains the design and uniformity of the wall-mounted air curtain, thereby ensuring that the system continues to reliably perform its anti-corrosion effect, while avoiding energy loss and potential safety hazards caused by high-temperature air leakage.

[0024] In one possible implementation, an adjusting baffle is installed on the air duct, which enables precise and flexible adjustment of the air volume of the wall-mounted air system. This allows for optimization of the air curtain intensity based on different boiler loads, coal characteristics, and actual corrosion prevention requirements, ensuring optimal improvement of wall-mounted oxygen concentration and suppression of corrosive gases with minimal air consumption. At the same time, it avoids excessive air supply from interfering with the main combustion zone, significantly improving the system's adaptability and operational economy.

[0025] In one possible implementation, an expansion joint is installed on the connecting air duct, which effectively absorbs and compensates for the unavoidable thermal expansion displacement during boiler operation. This eliminates the potential risk of thermal stress damaging the air duct system, air outlet installation structure, and boiler body, ensuring the sealing integrity and structural reliability of the connecting air duct and its interfaces. As a result, the wall-mounted air system can stably and leak-free deliver the designed air volume under all boiler operating conditions, maintain the continuous effectiveness of the anti-corrosion air curtain, and significantly extend the service life of the system.

[0026] In one possible implementation, the expansion joint can compensate for the thermal expansion deformation of the connecting duct caused by the high temperature of the furnace, prevent pipe cracking or flange leakage, and ensure the safe operation of the system.

[0027] In one possible implementation, the hanger can support the weight of the bellows and connecting pipes, preventing the pipes from sagging due to their own weight and causing leakage at the joints; at the same time, it reduces the impact on the boiler and ensures the stability of the system structure. Attached Figure Description

[0028] Figure 1 This application provides an overall structural schematic diagram of a boiler wall-mounted air system with burners arranged on the front and rear walls.

[0029] Figure 2 for Figure 1 A partial sectional view of AA.

[0030] The attached diagram is labeled as follows: 1. Boiler; 2. Secondary air duct structure; 3. Adjusting baffle; 4. Air duct; 5. Air box; 6. Connecting air duct; 7. Expansion joint; 8. Air outlet; 9. Hanger. Detailed Implementation

[0031] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0032] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly defined. The specific embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0034] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0035] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] like Figure 1 and Figure 2 As shown, this application discloses a boiler wall-mounted air and system with burners arranged on the front and rear walls. The boiler wall-mounted air and system with burners arranged on the front and rear walls may include a secondary air duct structure 2, multiple air ducts 4 on both sides, an air box 5, and a connecting air duct 6 installed on the front and rear walls of the boiler.

[0038] A set of adjacent air vents 8 are opened horizontally on the water-cooled wall fins of the boiler side wall.

[0039] One end of each of the multiple air ducts 4 is connected to the secondary air duct structure 2, and the other end is connected to the air box 5.

[0040] The other end of the bellows 5 is connected to the connecting air duct 6, which is connected to the air outlet 8 in sequence. This is used to form an air curtain from front to back on the side wall after air is supplied. In this way, when the bellows 5 supplies air, an air curtain from front to back can be formed on the side wall of the boiler 1, which effectively improves the atmosphere adhering to the wall.

[0041] In this embodiment, by opening adjacent air inlets 8 on the side wall water-cooled wall fins of the boiler 1 with burners arranged on the front and rear walls, and using the air box 5, connecting air duct 6 and air pipe 4 to supply air to form an air curtain, the oxygen content in the flue gas attached to the wall is effectively increased, and the content of hydrogen sulfide and carbon monoxide is reduced, thereby significantly alleviating or avoiding the high-temperature corrosion problem of the side wall water-cooled wall of the boiler 1 and ensuring the long-term safe operation of the boiler 1.

[0042] In one possible embodiment, the air vent 8 has two layers, and the two layers of air vent 8 are arranged side by side.

[0043] Optionally, the air vent 8 can be installed in two layers, with these two layers of air vent 8 arranged side by side. This design can increase the coverage of the air curtain and further improve the anti-corrosion effect.

[0044] In this embodiment, by opening two layers of parallel air vents 8, a more uniform and comprehensive air curtain can be formed on the side wall, which effectively improves the wall atmosphere of the entire side wall water-cooled wall, further reduces the risk of high-temperature corrosion, and improves the operating efficiency and safety of boiler 1.

[0045] In one possible embodiment, the duct 4 is connected to the secondary air duct structure 2 via an upward connection.

[0046] Specifically, the air inlet 8 of the duct 4 is directly opened at or connected to the top or upper side wall of the secondary air duct structure 2. This means that the air inlet 8 is located in the upper part of the secondary air duct.

[0047] At a predetermined location in the secondary air duct structure 2, a hole is made or a short pipe is welded to its top plate or upper side wall. One end of the duct 4 is connected to the hole or short pipe via a flange connection, welding, or other reliable sealing method. The connection point should be airtight to prevent air leakage.

[0048] In this embodiment, by horizontally opening adjacent groups of air vents 8 on the water-cooled wall fins of the boiler 1 sidewall, an air curtain covering the entire sidewall is formed, which effectively increases the oxygen content of the flue gas attached to the wall and reduces the concentration of hydrogen sulfide / carbon monoxide, thereby significantly alleviating or eliminating high-temperature corrosion of the water-cooled wall; at the same time, the use of the upper secondary air duct structure 2 to draw air reduces the amount of ash carried, realizing long-term anti-clogging, wear-resistant and stable operation of the system, ultimately ensuring the safe and economical operation of the boiler 1 and reducing maintenance costs.

[0049] In one possible embodiment, the connecting duct 6 and the air outlet 8 are connected in a downward-sloping manner.

[0050] Specifically, the axis of the connecting duct 6 is inclined downward relative to the horizontal plane, forming a certain downward inclination angle θ, for example, θ ≥ 5°, preferably between 15° and 70°.

[0051] The outlet end of the connecting duct 6 is connected to the upper inlet of the air outlet 8. That is, the inlet of the air outlet 8 is located below the outlet end of the connecting duct 6.

[0052] The inner wall of the connecting duct 6 forms a smooth flow channel that slopes continuously downwards from its inlet end to its outlet end, i.e., to the inlet of the air outlet 8. There are no horizontal sections or pits.

[0053] In this embodiment, the connecting duct 6 and the tuyer 8 are connected in a downward-sloping manner. Utilizing the principle of gravity self-cleaning, it ensures that trace amounts of ash or condensate carried in the airflow can smoothly slide down to the tuyer 8 and be discharged into the furnace. This effectively prevents ash deposition and blockage at the connection point and the inlet of the tuyer 8, ensuring a long-term stable supply of airflow to the air curtain and maintenance-free reliable operation of the system.

[0054] In one possible embodiment, the group of adjacent air vents 8 are arranged adjacent to each other in the horizontal direction of the side wall water-cooled wall fins to form an air curtain from front to back.

[0055] In this embodiment, the air outlets 8 are arranged horizontally adjacent to each other on the water-cooled wall fins of the side wall, ensuring that the delivered airflow is horizontal in the side wall and forms an air curtain on both sides of the wall. This effectively increases the overall oxygen concentration of the flue gas attached to the wall and simultaneously reduces the content of corrosive gases, completely solving the problem of local protection failure in the existing interval air supply method, and significantly improving the protection effect and reliability against high-temperature corrosion of the side wall water-cooled wall.

[0056] In one possible embodiment, the expansion joint 7 and the connecting duct 6 are also provided with a sealing gasket.

[0057] Specifically, the sealing gasket is placed between the flange end face of the expansion joint 7 and the flange end face of the connecting duct 6.

[0058] The gasket can be configured as a high-temperature resistant gasket, preferably made of a material with a temperature resistance rating of ≥300℃, such as a flexible graphite composite gasket, a metal spiral wound gasket, or a high-temperature resistant silicone rubber / fluororubber gasket with a specific formulation.

[0059] Furthermore, the gasket is clamped between the expansion joint 7 flange and the connecting duct 6 flange, and sufficient clamping force is applied by the flange connecting bolts to achieve an initial seal.

[0060] In this embodiment, a high-temperature resistant sealing gasket is provided between the expansion joint 7 and the flange interface of the connecting air duct 6, which effectively seals the interface gap caused by manufacturing and installation tolerances and thermal displacement, significantly reduces hot air leakage, ensures stable air volume and air pressure leading to the air outlet 8, maintains the design and uniformity of the wall-mounted air curtain, thereby ensuring that the system can continuously and reliably perform its anti-corrosion effect, while avoiding energy loss and potential safety hazards caused by high-temperature air leakage.

[0061] In one possible embodiment, the duct 4 is provided with an adjusting baffle 3 for adjusting the air volume.

[0062] Specifically, the adjusting baffle 3 is installed inside the duct section of the air duct 4, usually in a position on the air duct 4 that is easy to operate and maintain, for example, near the outlet of the secondary air duct structure 2 or near the inlet of the air box 5.

[0063] Optionally, the adjusting baffle 3 is a rotatable blade structure, with its rotation axis extending to the outside of the duct 4.

[0064] The rotating shaft of the adjusting baffle 3 is connected to a manual operating handle or an electric / pneumatic actuator, which adjusts the effective flow cross-sectional area of ​​the duct 4 by changing the blade angle.

[0065] In this embodiment, an adjusting baffle 3 is installed on the air duct 4, which enables precise and flexible adjustment of the air volume of the wall-mounted air system. It can optimize the air curtain intensity according to different boiler 1 loads, coal characteristics and actual corrosion prevention requirements, ensuring the best effect of increasing the wall-mounted oxygen concentration and suppressing corrosive gases with the lowest air consumption, while avoiding excessive air supply from interfering with the main combustion zone, thus significantly improving the system's adaptability and operating economy.

[0066] In one possible embodiment, an expansion joint 7 is provided on the connecting air duct 6 to compensate for thermal expansion displacement during boiler 1 operation.

[0067] Optionally, the expansion joint 7 is installed in series in the pipe section of the connecting duct 6, usually located at a critical part of the connecting duct 6 that needs to absorb displacement, such as the connection between the connecting duct 6 and the air box 5, or the middle of a long straight pipe section of the connecting duct 6 itself.

[0068] Optionally, the expansion joint 7 can be a non-metallic bellows type expansion joint 7, whose bellows is made of high-temperature resistant material and can withstand the wind temperature of the boiler 1 operating environment.

[0069] The expansion joint 7 is designed with sufficient axial extension, lateral offset, and angular deflection to absorb the multi-directional displacement caused by thermal expansion and contraction during boiler 1's start-up, shutdown, and variable load operation.

[0070] Specifically, the two ends of the expansion joint 7 are reliably connected to the adjacent pipe sections of the connecting duct 6 via flanges, ensuring airtightness.

[0071] In this embodiment, an expansion joint 7 is provided on the connecting air duct 6, which effectively absorbs and compensates for the unavoidable thermal expansion displacement during the operation of the boiler 1, eliminates the potential risk of thermal stress damaging the air duct system, the air outlet 8 installation structure and the boiler 1, and ensures the sealing integrity and structural reliability of the connecting air duct 6 and its interface. This ensures that the wall-mounted air system can stably and leak-free deliver the designed air volume under all operating conditions of the boiler 1, maintain the continuous effectiveness of the anti-corrosion air curtain, and significantly extend the service life of the system.

[0072] In one possible embodiment, the bellows 5 is provided with a hanger 9, which is mounted on the steel beam of the building structure.

[0073] Optionally, the lower end of the hanger 9 is fixedly connected to a pre-installed mounting ear plate or support on the top or side wall of the air box 5 by means of welding, bolting, or clamping.

[0074] The upper end of the hanger 9 is securely fixed to the steel beam of the boiler room building structure by bolts, welding, or special connectors. The steel beam is part of the main load-bearing structure of the building.

[0075] In this embodiment, a hanger 9 is installed on the wind box 5 and fixed to the steel beam of the building structure, providing a stable and reliable rigid support for the entire wall-mounted air system. This effectively bears the self-weight load of the wind box 5 and the pipeline, ensuring the spatial stability of the wind box 5, the connecting air duct 6 and the air outlet 8, preventing connection stress or deformation caused by gravity sagging, laying a solid structural foundation for the long-term safe and stable operation of the system, and facilitating coordinated operation with the thermal displacement compensation device of the boiler 1.

[0076] In one possible embodiment, the hanger 9 is configured as a spring structure to buffer the thermal expansion of the boiler 1's wall-mounted air system.

[0077] Optionally, the hanger 9 adopts a spring structure. For example, in a 350MW boiler 1, the stiffness of the spring hanger 9 is designed according to the weight of the wall-mounted air system on each side, and the spring compression is reserved at 20-30mm to buffer the thermal expansion displacement of the wall-mounted air system on each side.

[0078] In this embodiment, the spring hanger 9 can automatically compensate for the thermal expansion of the wall-mounted air system on each side, reduce structural damage caused by thermal stress, and at the same time avoid the hanger 9 from exerting rigid constraints on the air box 5, thus ensuring the stability of the system operation.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions for some or all of the technical features, do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A boiler wall attachment and system of front and back wall arranged burners, characterized by, It includes a secondary air duct structure (2) installed on the front and rear walls of the boiler (1), air ducts (4) on both sides, air boxes (5) and connecting air ducts (6); A set of adjacent air vents (8) are opened horizontally on the water-cooled wall fins of the side wall of the boiler (1); One end of each of the multiple air ducts (4) is connected to the secondary air duct structure (2), and the other end is connected to the air box (5); The other end of the bellows (5) is connected to the connecting air duct (6), and the connecting air duct (6) is connected to the air outlet (8) in sequence, so as to form an air curtain from front to back on the side wall after air is supplied.

2. The boiler wall-mounted air and system with burners arranged on the front and rear walls according to claim 1, characterized in that, The air vent (8) has two layers, and the two layers of air vent (8) are arranged side by side.

3. The boiler wall attachment air and system of claim 1, wherein, The air duct (4) is connected to the secondary air duct structure (2) by means of an upper connection.

4. The boiler wall-attached air and system of claim 1, wherein, The connecting duct (6) and the air outlet (8) are connected in a downward-sloping manner.

5. The boiler wall-attached air and system of claim 1, wherein, The group of adjacent air outlets (8) are arranged adjacently in the horizontal direction of the side wall water-cooled wall fins to form an air curtain from front to back.

6. The boiler wall-attached air and system of claim 1, wherein, An adjusting baffle (3) for adjusting the air volume is provided on the air duct (4).

7. The boiler wall-attached air and system of claim 1, wherein, An expansion joint (7) is provided on the connecting air duct (6) to compensate for the thermal expansion displacement of the boiler (1) during operation.

8. The boiler wall-mounted air and system with burners arranged on the front and rear walls according to claim 7, characterized in that, A sealing gasket is provided between the expansion joint (7) and the connecting air duct (6).

9. The boiler wall-mounted air and system with burners arranged on the front and rear walls according to claim 1, characterized in that, The bellows (5) is provided with a hanger (9), which is installed on the steel beam of the building structure.

10. The boiler wall-mounted air and system with burners arranged on the front and rear walls according to claim 9, characterized in that, The hanger (9) is configured as a spring structure to buffer the thermal expansion of the boiler (1) wall-mounted air system.

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