Water-cooled wall anti-corrosion system and method with cooperation of secondary air flow equalization and adherence air

Abstract

The invention discloses a water-cooled wall anti-corrosion system and method with secondary air flow equalization and adherence air cooperation. The system comprises a source adjusting unit, a tail end protection unit, a multi-parameter monitoring network unit and a controller. The source adjusting unit is an adjustable guide vane group in each secondary layer air bellow of the secondary air large air bellow and is in transmission connection with the angle executing mechanism; the tail end protection unit comprises a boiler side wall array type composite adherence air nozzle, an adherence air bellow and a compressed air pipeline, wherein the adherence air bellow and the compressed air pipeline are communicated; the multi-parameter monitoring network unit comprises an air volume sensor, a gas concentration sensor and a temperature sensor which are correspondingly arranged; and the controller is linked with each unit through a cable. According to the system, secondary air distribution can be dynamically adjusted, the stability of wall-attached air is improved, closed-loop regulation and control are achieved, the near-wall reducing atmosphere is eliminated in a two-dimensional mode, and the anti-corrosion effect and the boiler operation safety are improved.

Description

Technical Field

[0001] This invention belongs to the field of coal-fired boiler operation technology, specifically relating to a water-cooled wall corrosion prevention system and method that combines secondary air flow equalization and wall-mounted air. Background Technology

[0002] Against the backdrop of stringent environmental protection requirements and the widespread application of low-NOx burners, high-temperature corrosion of the water-cooled walls of offset combustion boilers has become a key issue restricting the long-term safe operation of the units. The root cause is the reducing atmosphere in the near-wall zone caused by improper combustion organization. The formation of this atmosphere stems from both macroscopic and microscopic factors: macroscopically, uneven distribution of secondary air volume among the burners causes disordered aerodynamic field and local oxygen deficiency in the furnace; microscopically, stagnation zones or vortices exist in the flue gas on the side walls, preventing reducing gases such as CO and H2S from being oxidized and discharged in a timely manner.

[0003] Currently, the industry mostly adopts single modification technology, such as adding fixed guide plates to the wind box to distribute airflow, or installing simple wall-mounted air nozzles for protection on the side walls. However, fixed guide plates cannot adapt to changes in load and coal type, and simple wall-mounted air nozzles are prone to unstable air pressure and air volume due to uneven air source, resulting in poor protection effect and easy burn-out of nozzles. The simple combination of the two lacks system-level coordinated control, making it difficult to optimize as a whole and even causing mutual interference. Summary of the Invention

[0004] The purpose of this invention is to provide a water-cooled wall corrosion prevention system and method that coordinates secondary air flow equalization and wall-mounted air flow, in order to solve the technical defects of existing boiler water-cooled wall corrosion prevention technologies, such as poor effect of single application, lack of coordinated control in combination, insufficient adaptability of fixed guide plates, unstable air supply of simple wall-mounted air flow, and easy damage to nozzles.

[0005] To achieve the above objectives, this application provides the following technical solution: A first aspect of this application provides a water-cooled wall corrosion protection system that combines secondary airflow equalization with wall-mounted airflow, comprising: The source adjustment unit is an adjustable guide vane assembly installed in each secondary layer of the secondary air box, and the adjustable guide vane assembly is connected to an angle actuator. The end protection unit includes a composite wall-mounted air nozzle arrayed on the water-cooled wall of the boiler side wall, and a wall-mounted air box and compressed air pipeline respectively connected to the composite wall-mounted air nozzle. The multi-parameter monitoring network unit includes an air volume sensor, a gas concentration sensor and a temperature sensor. The air volume sensor is installed on the corresponding air duct of the boiler burner, the gas concentration sensor is installed on the water-cooled wall of the boiler side wall, and the temperature sensor is embedded in the wall surface of the composite wall-mounted air nozzle. The controller is electrically connected to each sensor and angle actuator via signal transmission cables, and is also electrically connected to various regulators of the composite wall-mounted air nozzle via air valve adjustment control cables to achieve coordinated control of each unit.

[0006] In one optional embodiment, the adjustable guide vane assembly includes: Multiple adjustable guide vanes are arranged in parallel. The adjustable guide vanes have a streamlined airfoil cross-section structure and are made of heat-resistant stainless steel with a wear-resistant and corrosion-resistant coating on their surface.

[0007] In one optional embodiment, the angle actuator includes: The device comprises an actuator, a drive rod, and an adjusting rod. The actuator is connected to the drive rod via a transmission mechanism. The drive rod is hinged to the adjusting rod via a pin. The adjusting rod is rigidly connected to the rotating shaft of the adjustable guide vane.

[0008] In one alternative embodiment, the actuator is a pneumatic actuator or an electric actuator.

[0009] In one optional embodiment, the adjustable guide vane rotates around the axis with an adjustable angle range of -30° to +30°, and the zero-degree position of the adjustable guide vane is that its extension direction is parallel to the airflow direction of the secondary wind.

[0010] In one optional embodiment, the composite wall-mounted air nozzle is a three-layer concentric sleeve structure, which consists of a central compressed air pipe, a middle layer hot secondary air pipe, and an outer layer cooling protection pipe from the inside out.

[0011] In one optional embodiment, a compressed air regulator is provided on the central compressed air pipe, and a cooling air regulator is provided on the cooling protection cavity formed by the outer cooling protection pipe.

[0012] In one optional embodiment, a swirl nozzle is provided at the end of the central compressed air pipe, and a wear-resistant and high-temperature resistant ceramic head is embedded at the outermost end of the composite wall-mounted air nozzle. The ceramic head is connected to the outer end face of the composite wall-mounted air nozzle by a connecting rib to form an annular nozzle.

[0013] In one optional embodiment, a cooling protection cavity is formed between the middle layer hot secondary air duct and the outer layer cooling protection duct. A cooling baffle is provided in the cooling protection cavity, and the cooling baffle divides the cooling protection cavity into upper and lower chambers.

[0014] A second aspect of this application provides a method for using a water-cooled wall corrosion protection system that combines secondary airflow equalization and wall-mounted airflow, the method comprising: Step 1: Through the sensors of the multi-parameter monitoring network unit, the secondary air volume of the corresponding air duct of the burner, the atmosphere concentration of the water-cooled wall of the boiler side wall, and the wall surface temperature of the composite wall-mounted air nozzle are collected in real time, and the monitoring data is transmitted to the controller. Step 2: The controller drives the angle actuator to rotate the rotating shaft and adjustable guide vanes to a preset angle based on the collected monitoring data, thereby achieving uniform distribution of secondary air in each secondary layer air box and providing a stable air source for the wall-mounted air. Step 3: Based on the secondary air flow uniformity results, the controller controls the wall-mounted air box to deliver hot secondary air to the composite wall-mounted air nozzle, and at the same time controls the compressed air pipeline to deliver compressed air. The compressed air is mixed through multiple pipelines in the nozzle to form a composite jet, which is sprayed along the water-cooled wall to form a protective air film. Step 4: Based on the collected monitoring data, if the controller detects that the reducing atmosphere exceeds the standard, it will simultaneously increase the air volume ratio of the composite wall-mounted air nozzles in the corresponding area and fine-tune the angle of the adjustable guide vanes in the corresponding position to enhance the airflow supply to the area exceeding the standard. Step 5: Based on the collected monitoring data, if the temperature exceeds the limit, the controller immediately increases the opening of the cooling air regulator to enhance nozzle cooling, while simultaneously fine-tuning the airflow of the surrounding nozzles for compensation, and synchronously balancing the secondary air distribution based on the flow equalization logic.

[0015] Compared with the prior art, the present invention has the following beneficial effects: By replacing fixed guide vanes with adjustable guide vane assemblies, the secondary air distribution can be dynamically adjusted according to load and coal type, effectively solving the problems of uneven secondary air volume and poor adaptability of fixed structures. At the same time, the use of composite wall-mounted air nozzles in conjunction with dedicated wall-mounted air boxes and compressed air pipelines improves the shortcomings of simple wall-mounted air pressure and volume, poor protection effect, and easy nozzle burn-out. In addition, through multi-parameter monitoring and controller coordination, closed-loop control of source flow equalization and end protection is achieved, solving the problem of lack of coordination and easy mutual interference in simple combination of the two. Ultimately, the near-wall reducing atmosphere is eliminated from both macroscopic flow equalization and microscopic wall-mounted protection dimensions, significantly improving the corrosion resistance of water-cooled walls and the safety of boiler operation. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is an overall schematic diagram of a water-cooled wall corrosion protection system that combines secondary airflow equalization and wall-mounted airflow, provided by the present invention. Figure 2 A schematic diagram of the secondary air layer air box in a water-cooled wall corrosion protection system that combines secondary air flow equalization and wall-mounted air synergy, provided by the present invention; Figure 3 A schematic diagram of a composite wall-mounted air nozzle in a water-cooled wall corrosion protection system that combines secondary air flow equalization and wall-mounted air synergy, provided by the present invention; Figure 4 This invention provides a schematic diagram of the installation of a composite wall-mounted air nozzle in a water-cooled wall corrosion protection system that combines secondary air flow equalization and wall-mounted air synergy. In the diagram: 1. Boiler; 2. Wall-mounted air box; 3. Secondary air layer air box; 4. Secondary air main air box; 5. Adjustable guide vanes; 6. Composite wall-mounted air nozzle; 7. Compressed air pipeline; 8. Air volume sensor; 9. Angle actuator; 10. Gas concentration sensor; 11. Controller; 12. Gas concentration signal transmission cable; 13. Gas valve adjustment control cable; 14. Execution signal transmission cable; 15. Air volume signal transmission cable; 16. Rotating shaft; 17. Adjusting rod; 18. Drive rod; 19. Actuator; 20. Central compressed air pipe; 21. Middle layer hot secondary air pipe; 22. Cooling gas regulator; 23. Compressed air regulator; 24. Temperature sensor; 25. Outer layer cooling protection pipe; 26. Swirl nozzle; 27. Wear-resistant and high-temperature resistant ceramic head; 28. Guide block; 29. ​​Connecting rib. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] The present invention will now be described in further detail with reference to the accompanying drawings: like Figures 1-4 As shown, in a first aspect of the present invention, a water-cooled wall corrosion prevention system that coordinates secondary air flow equalization and wall-mounted air is provided, including a source adjustment unit consisting of adjustable guide vanes 5 arranged in each secondary layer air box 3 of the secondary air large air box 4, the adjustable guide vanes 5 being drivenly connected to an angle actuator 9; an end protection unit including composite wall-mounted air nozzles 6 arranged in an array on the water-cooled wall of the boiler 1, and wall-mounted air boxes 2 and compressed air pipelines 7 respectively connected to the composite wall-mounted air nozzles 6; and a multi-parameter monitoring network unit, including... The system includes an air volume sensor 8, a gas concentration sensor 10, and a temperature sensor 24. The air volume sensor 8 is installed on the corresponding air duct of the burner of the boiler 1. The gas concentration sensor 10 is installed on the water-cooled wall of the side wall of the boiler 1. The temperature sensor 24 is embedded in the wall surface of the composite wall-mounted air nozzle 6. The controller 11 is electrically connected to each sensor and the angle actuator 9 through signal transmission cables. The controller 11 is also electrically connected to various regulators of the composite wall-mounted air nozzle 6 through the gas valve adjustment control cable 13 to achieve coordinated control of each unit.

[0022] In implementation, the above system is integrated into the boiler body and its supporting flue gas system, without altering the main combustion form and furnace structure of the boiler. It is suitable for installation in newly built boilers and energy-saving retrofits of existing boilers, exhibiting strong versatility and adaptability. The system's air supply relies on the existing secondary air large air box 4 and each secondary layer air box 3 of the boiler, eliminating the need for additional large air supply equipment. Precise control of secondary air distribution can be achieved simply through internal structural optimization and the addition of adjustment components. The terminal protection units are arranged in an array along the water-cooled walls on the left and right sides of the boiler, covering critical areas prone to high-temperature corrosion and achieving comprehensive protection without blind spots. Multi-parameter monitoring network units are arranged as needed in the air boxes, air ducts, water-cooled walls, and nozzle bodies to achieve real-time acquisition of operating parameters across the entire area. The collaborative control center acts as the system's brain, uniformly receiving, processing, and outputting control commands to achieve intelligent collaborative operation of the entire system.

[0023] In this embodiment, the source adjustment unit is used to achieve uniform distribution of secondary air in the system. It is mainly arranged inside each secondary layer air box 3 of the secondary air large air box 4. It is used to actively adjust the flow rate and distribution of secondary air in each air duct, fundamentally solving the problems of uneven air supply to the burner and disordered aerodynamic field in the furnace. It provides a stable and uniform air source for the subsequent wall-mounted air system, while improving the overall combustion state in the furnace and reducing the formation of local oxygen-deficient areas.

[0024] Specifically, the source regulation unit is an adjustable guide vane 5, and multiple adjustable guide vanes 5 are arranged in parallel to form a guide vane group, such as... Figure 2 As shown.

[0025] To optimize the secondary airflow characteristics, reduce flow resistance within the duct, and prevent dust accumulation and coking on the blade surface, the adjustable guide vane 5 adopts a streamlined airfoil cross-section structure. Compared with traditional flat guide vanes, the streamlined structure can effectively reduce airflow impact loss, improve the uniformity of the flow field inside the wind box, and its smooth surface makes it less prone to dust accumulation, making it suitable for the long-term operating environment of dust-laden airflow in pulverized coal boilers.

[0026] The adjustable guide vane 5 is made of heat-resistant stainless steel, which can withstand long-term scouring under high-temperature secondary air conditions without deformation or corrosion. At the same time, the outer surface of the adjustable guide vane 5 is coated with an anti-wear and corrosion-resistant coating, which further improves the service life of the vane in high-temperature, dusty, and slightly corrosive airflow environments, and reduces the frequency of equipment maintenance and replacement costs.

[0027] The adjustable guide vanes 5 can be arranged in various ways. In addition to being arranged in the standard way inside the secondary air box 3, they can also be arranged in different positions of the secondary air duct according to the actual structure and flow field requirements of the boiler 1, so as to realize multi-level and graded air volume adjustment and improve the adjustment accuracy and coverage. At the same time, the adjustable guide vanes 5 can be arranged horizontally or vertically according to the on-site installation conditions, adapting to different forms of secondary air box 3 structures, so as to ensure that the adjustment effect reaches the optimal level.

[0028] The rear end of each adjustable guide vane 5 is rigidly fixed to the rotating shaft 16. The rotating shaft 16 extends laterally through the entire cross section of the secondary air box 3 and extends to the outside of the side wall on the opposite side of the secondary air box 3. It is installed on the side wall of the air box through the bearing seat to ensure that the rotating shaft 16 can rotate flexibly around its own axis without jamming or deviation during the rotation.

[0029] Furthermore, the rotational power of the rotating shaft 16 is provided by the angle actuator 9. Each adjustable guide vane 5 is equipped with an independent angle actuator 9. The angle actuator 9 is fixedly installed on the outer wall of the secondary layer wind box 3 to achieve independent drive and independent adjustment. It can accurately control the angle of a single blade or synchronously control multiple blades to meet different flow field adjustment needs.

[0030] The specific structure of the angle actuator 9 includes an actuator 19, a drive rod 18, and an adjusting rod 17, which are connected in sequence for transmission. The actuator 19 is a power output component and can be either a pneumatic actuator or an electric actuator. The pneumatic actuator is suitable for boiler environments with high explosion-proof requirements and has a rapid action response. The electric actuator has higher adjustment accuracy and better control stability, and can be freely selected according to the on-site usage conditions.

[0031] The output end of the actuator 19 is directly connected to the drive rod 18. The end of the drive rod 18 away from the actuator 19 is hinged to the adjusting rod 17 through a pin, realizing hinged transmission and ensuring no jamming during power transmission. The end of the adjusting rod 17 away from the drive rod 18 is rigidly fixed to the rotating shaft 16. When the actuator 19 outputs power, it sequentially drives the drive rod 18 and the adjusting rod 17 to move, and finally drives the rotating shaft 16 to rotate around the axis. The rotating shaft 16 then drives the adjustable guide vanes 5 to rotate synchronously, realizing continuous adjustment of the vane angle.

[0032] The adjustable guide vane 5 rotates around the shaft 16 within a strictly limited angle range of -30° to +30°. This angle range has been verified by multiple flow field simulations and field tests. It can meet the secondary air distribution adjustment requirements without causing local blockage of the air duct or distortion of the flow field due to excessive angle.

[0033] The zero-degree position of the adjustable guide vane 5 is defined as the vane extension direction being completely parallel to the direction of the secondary air mainstream. Depending on the installation direction of the vane, the parallel state can correspond to the horizontal airflow direction or the vertical airflow direction. The zero-degree position is the default initial position of the system and is suitable for boiler stable load operation. When it is necessary to increase or decrease the air volume of a certain air duct, the controller 11 controls the vane to deflect in the positive or negative direction to achieve precise adjustment of the air volume.

[0034] In this embodiment, the end protection unit is the core component of the system to achieve direct protection of the water-cooled wall. It mainly consists of composite wall-mounted air nozzles 6, wall-mounted air boxes 2, and compressed air pipelines 7 arranged in an array on the left and right side walls of the boiler 1. It is used to spray a uniform, stable, and highly rigid protective gas film into the near-wall area of ​​the water-cooled wall, isolate the reducing atmosphere from contact with the water-cooled wall tube wall, and at the same time blow away the flue gas in the local dead flow zone, eliminate the accumulation of corrosive gases such as CO and H2S, and directly block the conditions for high-temperature corrosion from the end.

[0035] The composite wall-mounted air nozzle 6 is the actuator of the end protection unit. It is evenly arranged in an array along the height and width of the water-cooled wall on the side wall of the boiler 1, covering all easily corroded areas of the water-cooled wall. The nozzle spacing is reasonably set according to the furnace size and flow field characteristics to ensure that the protection areas of adjacent nozzles overlap and there are no protection dead corners.

[0036] The composite wall-mounted air nozzle 6 body adopts a three-layer concentric sleeve structure, such as Figure 3 As shown, from the inside out, there are three layers: a central compressed air pipe 20, a middle layer hot secondary air pipe 21, and an outer layer cooling protection pipe 25. The three layers are independent of each other and do not interfere with each other, respectively realizing the three functions of compressed air delivery, hot secondary air delivery, and nozzle body cooling, forming a composite jet structure.

[0037] The central compressed air pipe 20 is the innermost sleeve, used to transport normal temperature high-pressure compressed air. The compressed air is provided by the compressed air system of Boiler 1 plant area, with stable pressure and adjustable flow rate.

[0038] A compressed air regulator 23 is installed on the central compressed air pipe 20. By adjusting the opening of the compressed air regulator 23, the delivery flow rate of compressed air can be changed in real time to meet the jet ejection requirements under different working conditions.

[0039] The end of the central compressed air pipe 20 is provided with a swirl nozzle 26. After the compressed air passes through the swirl nozzle 26, it is ejected in a rotating state. The swirl effect creates a negative pressure zone inside the nozzle, which effectively draws in and entrains the hot secondary air in the middle layer hot secondary air pipe 21. This allows the two airflows to mix fully inside the nozzle, forming a composite jet with moderate temperature, sufficient momentum, and strong rigidity, thereby improving the coverage and protection effect of the wall-mounted wind.

[0040] The middle-layer hot secondary air duct 21 is an intermediate layer sleeve, located between the central compressed air duct 20 and the outer cooling protection duct 25, forming an annular middle-layer hot secondary air cavity. The cavity outlet adopts a convergent structure design, which can accelerate the hot secondary air, improve the airflow outlet velocity and jet rigidity, and ensure that the airflow can effectively reach the near-wall area of ​​the water-cooled wall to form a stable air film.

[0041] The air source of the middle layer hot secondary air duct 21 is taken from the hot secondary air inside the wall-mounted air box 2. The wall-mounted air box 2 is connected to each secondary layer air box 3 of the boiler 1. After the hot secondary air is treated by the source regulating unit for flow equalization, it enters the wall-mounted air box 2, ensuring that the hot air flow rate and pressure of the hot air sent into the middle layer hot secondary air duct 21 are uniform and stable, fundamentally solving the problem of unstable air pressure and poor protection effect caused by uneven air source in the traditional wall-mounted air system.

[0042] The outermost cooling protection pipe 25 is the outermost sleeve, which forms a closed cooling protection cavity with the middle hot secondary air pipe 21. A small amount of room temperature compressed air is introduced into the cooling protection cavity as a cooling medium to continuously cool the outer wall of the composite wall-mounted air nozzle 6, so as to prevent the nozzle from being burned or deformed under the high temperature radiation of the furnace and the scouring of the flue gas.

[0043] A cooling gas regulator 22 is installed on the pipeline of the cooling protection chamber. By adjusting the opening of the cooling gas regulator 22, the flow rate of compressed air for cooling can be changed to adapt to the cooling requirements under different furnace temperature conditions and achieve precise control of the nozzle temperature.

[0044] A cooling baffle is installed between the middle layer hot secondary air duct 21 and the outer layer cooling protection duct 25, near the end of the nozzle outlet. The cooling baffle is located in the center of the cooling protection chamber, dividing the cooling protection chamber into two independent upper and lower chambers. The upper chamber is directly connected to the compressed air duct 7, through which compressed air for cooling is introduced. The lower chamber is a closed reflux chamber. The cooling airflow in the upper chamber flows along the length of the nozzle to the end, then turns and flows into the lower chamber to continue cooling the nozzle wall. The heated airflow can be discharged into the furnace or used as purging gas to clean the ash inside the flue gas duct, achieving efficient utilization of the cooling medium and avoiding energy waste.

[0045] The outermost end of the composite wall-mounted air nozzle 6 is fitted with a wear-resistant and high-temperature resistant ceramic head 27. The ceramic head 27 is made of high-purity alumina ceramic material, which has excellent high-temperature resistance, flame radiation resistance, and fly ash abrasion resistance. It can work stably for a long time in extreme furnace environments and effectively protect the nozzle outlet structure from damage.

[0046] The outermost part of the ceramic head 27 is fixedly connected to the outer end face of the composite wall-mounted air nozzle 6 through multiple connecting ribs 29. The connecting ribs 29 are evenly distributed, and an annular nozzle channel is formed between adjacent connecting ribs 29. After the composite airflow is mixed, it is evenly sprayed out in all directions through the annular nozzle, forming a large-area, fully covered protective air film along the water-cooled wall surface, thus achieving all-round protection of the water-cooled wall.

[0047] Inside the outlet of the composite wall-mounted air nozzle 6, between the swirling nozzle 26 and the middle-layer hot secondary air duct 21, a guide block 28 is also provided. The guide block 28 is used to guide and rectify the mixed airflow, further improving the uniformity and rigidity of the jet, and preventing the airflow from forming vortices and deflection inside the nozzle.

[0048] Specifically, the flow guide block 28 is located on the ceramic head 27.

[0049] In this embodiment, the multi-parameter monitoring network unit is the foundation for the system to achieve real-time perception and intelligent control. It is responsible for collecting key parameters of system operation across the entire domain, providing accurate and real-time data support for the collaborative control center. The monitored parameters include three major categories: secondary air volume, sidewall water-cooled wall atmosphere concentration, and composite wall-mounted air nozzle surface temperature, comprehensively covering the three major monitoring dimensions of wind box flow field, furnace atmosphere, and equipment status.

[0050] The multi-parameter monitoring network unit includes an air volume sensor 8, a gas concentration sensor 10, and a temperature sensor 24. Each sensor is arranged at a fixed point according to its functional requirements to ensure the representativeness and accuracy of the monitoring data.

[0051] The air volume sensor 8 is a thermal air volume sensor, which is fixedly installed on the secondary air duct corresponding to each burner of the boiler 1. Each burner duct corresponds to at least one air volume sensor 8, which collects parameters such as instantaneous flow rate, wind speed, and wind pressure of the secondary air in each duct in real time. The monitoring data directly reflects the flow equalization effect of the source regulation unit and provides direct data basis for the angle adjustment of the adjustable guide vane 5.

[0052] The gas concentration sensor 10 adopts an array arrangement and is installed at a designated elevation on the water-cooled wall of the boiler 1 side wall, specifically in the easily corroded area above the wall-mounted air box 2. It monitors the reducing atmosphere concentration in the near-wall area of ​​the water-cooled wall in real time, focusing on the content of corrosive gases such as CO and H2S. When the gas concentration exceeds the preset safety threshold, it immediately sends an alarm signal to the collaborative control center to trigger the local atmosphere correction program.

[0053] Temperature sensor 24 is a patch thermocouple, which is embedded in the outer wall of the composite wall-mounted air nozzle 6 and directly contacts the nozzle wall to monitor the operating temperature of the nozzle body in real time. This prevents the nozzle from overheating and burning due to the high temperature of the furnace. When the monitored temperature exceeds the preset protection threshold, the nozzle high temperature protection program is triggered to ensure the safe operation of the equipment.

[0054] All sensors are designed to withstand high temperatures and resist interference, making them suitable for the high-temperature, dusty, and electromagnetically interference operating environment of boiler sites. They provide stable and accurate monitoring data without signal drift or data loss, thus providing a reliable data foundation for hierarchical and collaborative control of the system.

[0055] In this embodiment, the collaborative control center comprises a controller 11, an execution signal transmission cable 14, an airflow signal transmission cable 15, a gas concentration signal transmission cable 12, and a gas valve adjustment control cable 13. The airflow sensor 8 is electrically connected to the controller 11 via the airflow signal transmission cable 15, uploading airflow data in real time. The gas concentration sensor 10 is electrically connected to the controller 11 via the gas concentration signal transmission cable 12, uploading atmospheric concentration data in real time. The temperature sensor 24 is connected to the controller 11 via a corresponding signal cable, uploading nozzle temperature data.

[0056] The controller 11 is electrically connected to the angle actuator 9 via the execution signal transmission cable 14. Based on the monitoring data, the controller 11 drives the angle actuator 9 to adjust the rotation angle of the adjustable guide vane 5. The controller 11 is also electrically connected to the compressed air regulator 23 and the cooling air regulator 22 on the composite wall-mounted air nozzle 6 via the air valve adjustment control cable 13. The controller 11 adjusts the compressed air flow and cooling air flow in real time to achieve precise control of the end protection unit.

[0057] The collaborative control center adopts a hierarchical decision-making and collaborative optimization intelligent control strategy. Based on the different operating conditions of boiler 1, flow field state, atmosphere concentration, and equipment temperature, it is divided into three control levels: Level 1 collaboration, Level 2 collaboration, and Level 3 collaboration. These levels advance step by step and cooperate in a coordinated manner to achieve full-scenario coverage from basic flow equalization to local correction and system protection. The specific control logic is as follows: Level 1 coordination is the basic operating mode of the system, which is applicable to the normal and stable operation of boiler 1. Its core objective is to prioritize ensuring the balance of secondary air volume in each burner, providing the basic conditions for stable combustion in the furnace, and at the same time providing a stable and uniform air source for the wall-mounted air system. It is the operating foundation of the entire prevention and control system.

[0058] The controller 11 receives the air volume data of each air duct uploaded by the air volume sensor 8 in real time, compares the air volume deviation between each air duct, and when the deviation value exceeds the preset allowable range, it immediately drives the angle actuator 9 at the corresponding position to adjust the rotation angle of the adjustable guide vane 5, increase or decrease the ventilation area of ​​the corresponding air duct, quickly correct the air volume deviation, and make the air volume of each burner quickly reach a uniform state.

[0059] In the first-level collaborative mode, the end protection unit operates in the basic mode. The wall-mounted air box 2 uses stable hot secondary air after flow equalization treatment. The compressed air regulator 23 and the cooling air regulator 22 maintain the basic opening. The composite wall-mounted air nozzle 6 continuously outputs a stable protective air film to achieve basic protection of the water-cooled wall.

[0060] The secondary coordination mode is a precise adjustment mode of the system. The triggering condition is that the concentration of reducing atmosphere (such as CO concentration) at one or more points on the side wall water-cooled wall exceeds the preset primary threshold, and the air volume uniformity of each burner has reached the standard. It is determined that there is a local flow dead zone in this area, which is a micro-flow field problem. It needs to be targeted and corrected by combining end enhancement and source fine adjustment.

[0061] After receiving the exceedance signal from the gas concentration sensor 10, the controller 11 immediately activates the two-level collaborative algorithm and executes two synchronized actions: In the first step, the controller 11 adjusts the control cable 13 via the air valve to control the opening of the hot air valve of the composite wall-mounted air nozzle 6 in the corresponding area. At the same time, it increases the opening of the compressed air regulator 23 according to the preset ratio, improves the auxiliary compressed air mixing ratio, enhances the nozzle jet speed and rigidity, strengthens the airflow coverage of the excessive area, quickly disperses the reducing gas, and eliminates local dead zones.

[0062] The second step is for the controller 11 to feed back the location information of the atmospheric deviation point to the source adjustment unit. Using the built-in windbox flow field-sidewall atmosphere influence relationship model, which is trained by CFD flow field simulation and on-site historical operation data, the controller 11 can slightly adjust the angle of the adjustable guide vane 5 at the corresponding position so that more secondary air tends to flow to the burner or windbox outlet corresponding to the deviation area, providing support from the macro flow field level and realizing the coordinated correction of the source and the end.

[0063] Level 3 coordination is the highest level of protection mode for the system, which includes two major functions: high-temperature nozzle protection and adaptive operating conditions, ensuring the safe and stable operation of the system under extreme and variable operating conditions.

[0064] When the temperature sensor 24 built into any of the composite wall-mounted air nozzles 6 detects that the wall temperature exceeds the limit, the controller 11 immediately triggers the nozzle protection program. First, it increases the opening of the cooling air regulator 22 to enhance the cooling airflow and quickly reduce the nozzle temperature. At the same time, it temporarily and slightly reduces the hot secondary air volume of the nozzle, and the nozzles in the adjacent area increase the air volume to compensate, ensuring that the overall protection effect is not affected. The controller 11 synchronously controls the source adjustment unit to rebalance the air volume to avoid local air volume fluctuations affecting the overall flow field.

[0065] When the load and coal type of boiler 1 change significantly, traditional anti-corrosion systems cannot adapt quickly and are prone to problems such as adjustment lag and protection failure. The controller 11 of this system has a pre-stored optimal operating database for different loads and coal types. When a significant change in boiler operating conditions is detected, it automatically matches the corresponding optimized parameters and synchronously switches the overall angle mode of the adjustable guide vane 5, the total air volume mode of the wall-mounted air system, and the compressed air ratio mode to achieve global collaborative self-adaptation without manual intervention, ensuring the best anti-corrosion effect under different operating conditions.

[0066] During normal operation of boiler 1, the water-cooled wall anti-corrosion system, which coordinates the secondary air flow and the wall-mounted air flow, operates synchronously throughout the entire process. The multi-parameter monitoring network unit collects key parameters such as air volume, atmosphere concentration, and nozzle temperature in real time and across the entire area. All data is synchronously uploaded to the controller 11 in the collaborative control center. The controller 11 outputs control commands in real time according to the control strategy of hierarchical decision-making and collaborative optimization, forming a complete closed-loop workflow of monitoring, decision-making, execution, and feedback.

[0067] When the system is working, the primary adjustment unit first achieves active equalization of secondary air flow, eliminating burner oxygen deficiency and furnace flow field turbulence caused by uneven air supply at the macro level, thus cutting off the root cause of high-temperature corrosion. On this basis, the terminal protection unit uses uniform and stable hot secondary air and compressed air to form a high-rigidity composite jet, forming a continuous and complete protective gas film along the water-cooled wall surface. This isolates the reducing atmosphere at the micro level, disperses the flue gas in local dead zones, and constructs a key barrier for the prevention and control of high-temperature corrosion.

[0068] When the reducing atmosphere exceeds the standard in a local area of ​​the sidewall, the system automatically enters the secondary collaborative mode, the terminal nozzle strengthens the injection, and the source blades finely adjust the guidance to form a targeted treatment effect and quickly eliminate the problem of exceeding the standard; when the nozzle has a high temperature risk or the boiler operating conditions change significantly, the system automatically enters the tertiary collaborative mode to realize equipment protection and operating condition self-adaptation, and ensure the long-term stable operation of the system.

[0069] The entire system deeply integrates the active flow equalization of the secondary air box with the intelligent composite wall-mounted air, constructing a complete high-temperature corrosion prevention chain from the air box outlet to the water-cooled wall. Through a multi-variable coupled control model, it realizes information exchange and command coordination between the two units, breaking through the technical bottleneck of traditional single technology operating independently with limited effect. It fundamentally solves the industry problem of high-temperature corrosion of boiler water-cooled walls under the background of stringent environmental protection requirements and the large-scale application of low-NOx burners.

[0070] The water-cooled wall corrosion prevention system described in this embodiment, which combines secondary airflow equalization and wall-adhering airflow, has significant innovation and outstanding beneficial effects compared to existing traditional technologies. First, the system innovatively integrates the two subsystems of active airflow equalization in the secondary air box and intelligent composite wall-adhering airflow, breaking the limitations of single airflow equalization or single wall-adhering airflow in traditional technologies. It constructs a complete, closed-loop high-temperature corrosion prevention system from the air box outlet to the water-cooled wall surface, realizing the organic combination of macroscopic flow field regulation and microscopic atmosphere protection, and greatly improving the prevention effect.

[0071] Secondly, a hierarchical decision-making and collaborative optimization intelligent control method is proposed. A multi-variable coupled control model of air volume deviation, atmosphere concentration and nozzle temperature is established to realize real-time feedback and dynamic coordination between the source regulation unit and the end protection unit. The two systems no longer operate independently, but cooperate and optimize each other, which completely solves the problems of mutual interference and regulation lag caused by simple combination.

[0072] Then, the system adopts a modular design, and the source regulation unit, end protection unit, monitoring unit and control unit can be produced, installed and debugged independently. They are then integrated through a collaborative control center. This is particularly suitable for the phased technical transformation of existing power plant boilers, which does not require long-term boiler shutdown for construction, and greatly reduces the difficulty of transformation implementation and operational risks.

[0073] Because the adjustable guide vane 5 adopts a streamlined airfoil section and heat-resistant stainless steel material, and is combined with a wear-resistant and corrosion-resistant coating on the surface, it has a long service life and high adjustment accuracy; the composite wall-mounted air nozzle 6 adopts a three-layer sleeve structure and cooling protection design, and is combined with a wear-resistant and high-temperature resistant ceramic head 27, which completely solves the problems of easy burning and wear of traditional nozzles, and significantly improves the reliability of the equipment.

[0074] Finally, the system is adaptable to the boiler's full-load and all-coal-type operating conditions, and has an automatic operating condition self-adaptation function. It does not require frequent manual adjustments, has a high degree of automation, can effectively reduce the labor intensity of operators, and at the same time reduce the number of unplanned shutdowns of the boiler caused by high-temperature corrosion, thereby improving the unit's operating economy and safety.

[0075] In summary, through structural innovation, control innovation, and integration innovation, this system comprehensively solves various defects in existing boiler water-cooled wall high-temperature corrosion prevention technologies. It has many advantages such as precise adjustment, comprehensive protection, stable operation, strong adaptability, and convenient modification, and has extremely high engineering application value and market promotion prospects.

[0076] A second aspect of this application provides a method for using a water-cooled wall corrosion protection system that combines secondary airflow equalization and wall-mounted airflow. The method employs the water-cooled wall corrosion protection system with the secondary airflow equalization and wall-mounted airflow coordination described above, and includes: Step 1: Through the sensors of the multi-parameter monitoring network unit, the secondary air volume of the corresponding air duct of the burner, the atmosphere concentration of the water-cooled wall of the boiler 1 side wall and the wall surface temperature of the composite wall-mounted air nozzle 6 are collected in real time, and the monitoring data is transmitted to the controller 11. Step 2: According to the collected monitoring data, the controller 11 drives the angle actuator 9 to rotate the rotating shaft 16 and the adjustable guide vane 5 to a preset angle, so as to achieve uniform distribution of secondary air in each secondary layer air box 3 and provide a stable air source for the wall-mounted air. Step 3: Based on the secondary air flow uniformity results, the controller 11 controls the wall-mounted air box 2 to deliver hot secondary air to the composite wall-mounted air nozzle 6, and at the same time controls the compressed air pipeline 7 to deliver compressed air. The compressed air is mixed through multiple pipelines in the nozzle to form a composite jet, which is sprayed along the water-cooled wall to form a protective air film. Step 4: Based on the collected monitoring data, if the controller 11 detects that the reducing atmosphere exceeds the standard, it will simultaneously increase the air volume ratio of the composite wall-mounted air nozzle 6 in the corresponding area and finely adjust the angle of the adjustable guide vane 5 at the corresponding position to enhance the airflow supply to the area exceeding the standard. Step 5: If the temperature exceeds the limit according to the collected monitoring data, the controller 11 will immediately increase the opening of the cooling air regulator 22 to enhance the nozzle cooling, while finely adjusting the air volume of the surrounding nozzles for compensation, and synchronously balancing the secondary air distribution based on the flow equalization logic.

[0077] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A water-cooled wall corrosion protection system that combines secondary airflow equalization with wall-mounted airflow, characterized in that, include: The source adjustment unit is an adjustable guide vane assembly installed in each secondary layer of the secondary air box, and the adjustable guide vane assembly is connected to an angle actuator. The end protection unit includes a composite wall-mounted air nozzle arrayed on the water-cooled wall of the boiler side wall, and a wall-mounted air box and a compressed air pipeline respectively connected to the composite wall-mounted air nozzle. The multi-parameter monitoring network unit includes an air volume sensor, a gas concentration sensor and a temperature sensor. The air volume sensor is installed on the corresponding air duct of the boiler burner, the gas concentration sensor is installed on the water-cooled wall of the boiler side wall, and the temperature sensor is embedded in the wall surface of the composite wall-mounted air nozzle. The controller is electrically connected to each sensor and angle actuator via signal transmission cables, and is also electrically connected to various regulators of the composite wall-mounted air nozzle via air valve adjustment control cables to achieve coordinated control of each unit.

2. The water-cooled wall corrosion protection system with secondary airflow equalization and wall-mounted airflow coordination according to claim 1, characterized in that, The adjustable guide vane assembly includes: Multiple adjustable guide vanes are arranged in parallel. The adjustable guide vanes have a streamlined airfoil cross-section structure and are made of heat-resistant stainless steel with a wear-resistant and corrosion-resistant coating on their surface.

3. The water-cooled wall corrosion protection system with secondary airflow equalization and wall-mounted airflow coordination as described in claim 1, characterized in that, The angle actuator includes: The device comprises an actuator, a drive rod, and an adjusting rod. The actuator is connected to the drive rod via a transmission mechanism. The drive rod is hinged to the adjusting rod via a pin. The adjusting rod is rigidly connected to the rotating shaft of the adjustable guide vane.

4. The water-cooled wall corrosion protection system with secondary airflow equalization and wall-mounted airflow coordination according to claim 3, characterized in that, The actuator is either a pneumatic actuator or an electric actuator.

5. The water-cooled wall corrosion protection system with secondary airflow equalization and wall-mounted airflow coordination according to claim 3, characterized in that, The adjustable guide vane can rotate around the axis with an adjustable angle range of -30° to +30°, and the zero-degree position of the adjustable guide vane is that its extension direction is parallel to the airflow direction of the secondary wind.

6. The water-cooled wall corrosion protection system according to claim 1, characterized in that, The composite wall-mounted air nozzle has a three-layer concentric sleeve structure, which consists of a central compressed air pipe, a middle layer hot secondary air pipe, and an outer layer cooling protection pipe from the inside out.

7. The water-cooled wall corrosion protection system according to claim 6, characterized in that, A compressed air regulator is installed on the central compressed air pipe, and a cooling air regulator is installed on the cooling protection cavity formed by the outer cooling protection pipe.

8. The water-cooled wall corrosion protection system according to claim 6, characterized in that, The end of the central compressed air pipe is provided with a swirl nozzle, and the outermost end of the composite wall-mounted air nozzle is inlaid with a wear-resistant and high-temperature resistant ceramic head. The ceramic head is connected to the outer end face of the composite wall-mounted air nozzle by a connecting rib to form an annular nozzle.

9. The water-cooled wall corrosion protection system according to claim 6, characterized in that, A cooling protection cavity is formed between the middle layer hot secondary air duct and the outer layer cooling protection duct. A cooling baffle is provided in the cooling protection cavity, which divides the cooling protection cavity into upper and lower chambers.

10. A method for using a water-cooled wall corrosion protection system that combines secondary airflow equalization and wall-mounted airflow, characterized in that, The method is carried out using the water-cooled wall corrosion protection system with secondary airflow equalization and wall-mounted airflow coordination as described in any one of claims 1-9, including: Step 1: Through the sensors of the multi-parameter monitoring network unit, the secondary air volume of the corresponding air duct of the burner, the atmosphere concentration of the water-cooled wall of the boiler side wall, and the wall surface temperature of the composite wall-mounted air nozzle are collected in real time, and the monitoring data is transmitted to the controller. Step 2: The controller drives the angle actuator to rotate the rotating shaft and adjustable guide vanes to a preset angle based on the collected monitoring data, thereby achieving uniform distribution of secondary air in each secondary layer air box and providing a stable air source for the wall-mounted air. Step 3: Based on the secondary air flow uniformity results, the controller controls the wall-mounted air box to deliver hot secondary air to the composite wall-mounted air nozzle, and at the same time controls the compressed air pipeline to deliver compressed air. The compressed air is mixed through multiple pipelines in the nozzle to form a composite jet, which is sprayed along the water-cooled wall to form a protective air film. Step 4: Based on the collected monitoring data, if the controller detects that the reducing atmosphere exceeds the standard, it will simultaneously increase the air volume ratio of the composite wall-mounted air nozzles in the corresponding area and fine-tune the angle of the adjustable guide vanes in the corresponding position to enhance the airflow supply to the area exceeding the standard. Step 5: Based on the collected monitoring data, if the temperature exceeds the limit, the controller immediately increases the opening of the cooling air regulator to enhance nozzle cooling, while simultaneously fine-tuning the airflow of the surrounding nozzles for compensation, and synchronously balancing the secondary air distribution based on the flow equalization logic.

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