A method and device for on-line correction of oxygen content in operation of a power plant boiler

Abstract

The application discloses a kind of power plant boiler operation oxygen amount online correction method and device, multiple existing oxygen sensors are arranged and arranged on rotating frame structure and end is equipped with oxygen sensor mounting seat, rotating frame structure is driven to rotate by servo motor, to complete the radial switching action of multiple oxygen sensors, the axial disengagement action of oxygen sensor and the main flange interface of flue outer wall is by the telescopic movement of electric push rod in axial direction, driving switching rod pulls oxygen sensor mounting seat to complete.The application aims at the abnormal alarm condition of oxygen sensor at single position in power plant boiler operation oxygen amount online monitoring system, and power plant operation center remote control power plant boiler operation oxygen amount online correction device can realize the axial plug and radial switching action of oxygen sensor, improve the detection quality of power plant boiler operation oxygen amount online monitoring system, and it is beneficial to power plant operation center to complete accurate correction of operation oxygen amount in time.

Description

Technical Field

[0001] This invention relates to the technical field of power plant boiler monitoring, and in particular to a method and device for online correction of oxygen levels in power plant boilers. Background Technology

[0002] Currently, in thermal power plants, the hazards of excessive oxygen levels in boiler operation include: 1. Excessive output of major fans, leading to insufficient adjustment margin of fan blades; 2. Excessive oxygen inevitably leads to excessively high wall temperatures. The wall temperature of Unit 1 approached the alarm value under high load, significantly increasing the need for desuperheating water and reducing economic efficiency; 3. Increased flue gas temperature reduces boiler economic efficiency; 4. Increased output and current of various fans increase the plant's power consumption; 5. Excessive oxygen increases flue gas velocity, leading to increased carbon content in the ash at the air preheater outlet and increased mechanical incomplete combustion losses; it also makes the lateral distribution of flue gas more uneven; 6. Increased generation of sulfur oxides and nitrogen oxides.

[0003] The hazards of excessively low oxygen levels include: 1. Reduced oxygen supply in the later stages leads to incomplete mechanical and chemical combustion losses of pulverized coal; 2. Increased reducing gases make the furnace more prone to coking, resulting in harsh wall temperature operating conditions over long periods; 3. Low oxygen levels reduce the combustion stability of the furnace, which is detrimental to the safety of the furnace chamber; 4. Prolonged combustion time and increased flue gas temperature.

[0004] Therefore, power plants will install an online oxygen monitoring system to monitor the oxygen level in the flue gas duct, which involves installing multiple oxygen sensors inside the flue gas duct, such as... Figure 1 As shown, the oxygen sensor is inserted into the flue from the outside. High accuracy in monitoring the operating oxygen level allows for efficient correction of the operating oxygen level, preventing the hazards of excessively high or low oxygen levels. Currently, in power plant boiler online oxygen level monitoring systems, abnormal alarms from oxygen sensors at a single location typically require specialized personnel for inspection and repair. If an abnormality occurs, system shutdown may be necessary, potentially leading to significant economic losses. To address this, we have specifically developed an online oxygen level correction method and device for power plant boilers. Summary of the Invention

[0005] To address the aforementioned existing problems, this invention provides a method and apparatus for online calibration of oxygen levels in power plant boilers. When an oxygen sensor at a single location in the online oxygen monitoring system for power plant boilers experiences an abnormal alarm, the power plant operation center can remotely control the online oxygen calibration device to perform axial insertion / removal and radial switching actions on the oxygen sensor. This improves the detection quality of the online oxygen monitoring system for power plant boilers and facilitates timely and accurate calibration of the operating oxygen levels by the power plant operation center.

[0006] The technical solution of this invention is as follows:

[0007] This invention provides a method for online correction of oxygen levels in power plant boilers, comprising the following steps:

[0008] S1. In response to an abnormal alarm caused by an oxygen sensor at a single location in the online oxygen monitoring system for power plant boiler operation, the electric push rod in the online oxygen correction device for power plant boiler operation is remotely controlled by the power plant operation center to move away from the outer wall of the flue. The switching rod connected to the electric push rod is driven to move away from the outer wall of the flue, so that the abnormal oxygen sensor exits from the flue.

[0009] S2. The servo motor in the online oxygen correction device for the boiler operation of the power plant is remotely controlled by the power plant operation center to drive the rotating frame structure to rotate clockwise until the other oxygen sensors on the rotating frame structure are concentric with the main flange interface on the outer wall of the flue.

[0010] S3. The electric push rod in the online oxygen correction device for the power plant boiler is retracted by remote control of the power plant operation center. The switching rod moves towards the outer wall of the flue until the switched oxygen sensor is pushed into the main flange interface on the outer wall of the flue by the switching rod.

[0011] S4. If the operating oxygen level detected by the switched oxygen sensor is equal to the operating oxygen level detected by the oxygen sensor before the switch, then stop the operation of the online calibration device for operating oxygen level of the power plant boiler and investigate other causes; if the operating oxygen level detected by the switched oxygen sensor is not equal to the operating oxygen level detected by the oxygen sensor before the switch, then repeat steps S1-S3 again, switch the oxygen sensor again, and compare the operating oxygen level detection data of the oxygen sensor after the first switch with that of the oxygen sensor after the second switch.

[0012] S5. If the operating oxygen value of the oxygen sensor after the first switch is equal to that of the oxygen sensor after the second switch, then follow steps S1-S3 again. In step S2, the servo motor in the online oxygen calibration device for the power plant boiler is remotely controlled by the power plant operation center to drive the rotating frame structure to rotate counterclockwise, switching back to the oxygen sensor after the first switch. If the operating oxygen value of the oxygen sensor after the first switch is not equal to that of the oxygen sensor after the second switch, then stop the operation of the online oxygen calibration device for the power plant boiler and investigate other causes.

[0013] Furthermore, the online oxygen calibration device for power plant boiler operation includes an oxygen sensor, a cylinder, a switching rod, an oxygen sensor mounting base, a servo motor, an electric push rod, and a rotating frame structure. On the end face of the cylinder near the outer wall of the flue, a portion away from the center of the end face is provided with an external flange for connecting to the main flange interface on the outer wall of the flue. A rotating frame structure is installed inside the cylinder, connected to a servo motor on the end of the cylinder away from the outer wall of the flue. Multiple oxygen sensors are evenly distributed on the rotating frame structure. An oxygen sensor mounting base is provided at the end of each oxygen sensor away from the outer wall of the flue. A switching rod for pushing the oxygen sensor out of the external flange is attached to the mounting base of the oxygen sensor coaxial with the external flange. A connecting block is provided at the end of the switching rod extending away from the outer wall of the flue and protruding outwards from the cylinder. An electric push rod is located outside the cylinder at the end of the connecting block away from the switching rod.

[0014] This invention also provides an online oxygen level correction device for power plant boilers, comprising an oxygen sensor, a cylinder, a support column, a switching rod, an oxygen sensor mounting base, a servo motor, an electric push rod, and a rotating frame structure. The cylinder has an external flange on its end face near the outer wall of the flue, located away from the center of the end face, for connecting to the main flange interface on the outer wall of the flue. A support column is located on the part of the cylinder below the external flange, for abutting against the outer wall of the flue. A rotating frame structure is installed inside the cylinder, connected to a servo motor on the end of the cylinder away from the outer wall of the flue. Multiple oxygen sensors are evenly distributed on the rotating frame structure. An oxygen sensor mounting base is located at the end of each oxygen sensor away from the outer wall of the flue. A switching rod for pushing the oxygen sensor out of the external flange is attached to the mounting base of the oxygen sensor coaxial with the external flange. A connecting block is located at the end of the switching rod extending away from the outer wall of the flue and extending outwards from the cylinder. An electric push rod is located outside the cylinder at the end of the connecting block away from the switching rod.

[0015] Furthermore, the oxygen sensor mounting base has a U-shaped structure and a rear through hole for the oxygen sensor to pass through at the end near the outer wall of the flue. The flange of the oxygen sensor can be bolted around the rear through hole. A docking sleeve is provided on the side wall of the oxygen sensor mounting base away from the rear through hole. A limiting baffle is provided at the front end of the docking sleeve. Several elastic locking structures are provided on the outer wall of the docking sleeve. The elastic locking structures can be locked into the locking groove on the end of the switching rod, so that the switching rod can drive the oxygen sensor mounting base to move away from the outer wall of the flue.

[0016] Furthermore, the elastic locking structure includes an elastic locking seat, a spring, a fixed cylinder, and a locking block. The fixed cylinder is fixedly disposed on the outer wall of the docking sleeve and communicates with the interior of the docking sleeve. An elastic locking seat is spirally nested on the fixed cylinder. A spring is provided on the portion of the elastic locking seat facing the interior of the fixed cylinder. A locking block is provided on the end of the spring extending inside the fixed cylinder and facing the interior of the docking sleeve. The locking block extends from the fixed cylinder into the docking sleeve and can be embedded in the locking groove on the end of the switching rod.

[0017] Furthermore, the end face of the oxygen sensor mounting base facing the axis of the rotating frame structure is provided with a through hole for the wires of the oxygen sensor to pass through.

[0018] Furthermore, the rotating frame structure includes a first support plate, a rotating shaft, and a second support plate. The end of the rotating shaft away from the outer wall of the flue is connected to a servo motor outside the cylinder and is driven to rotate by the servo motor. The end of the rotating shaft away from the outer wall of the flue is provided with the first support plate, and the end near the outer wall of the flue is provided with the second support plate. A plurality of oxygen sensors are evenly distributed between the first support plate and the second support plate with the center line of the rotating shaft as the axis. The end of the oxygen sensor near the outer wall of the flue is embedded in the second support plate, and the limiting baffle on the end away from the outer wall of the flue is embedded in the first support plate.

[0019] Furthermore, the end of the rotating shaft near the outer wall of the flue is connected to the outside of the cylinder. The rotating shaft adopts a hollow cylindrical structure and has several elongated holes evenly distributed on its side wall, which extend along its axis and are used for the wires of the oxygen sensor to extend into the rotating shaft, so that the wires of the oxygen sensor extend outward through the rotating shaft and are electrically connected to the controller outside the cylinder.

[0020] Furthermore, the end face of the second support plate facing the outer wall of the flue is provided with a sealing plate made of high-temperature resistant heat insulation material.

[0021] Furthermore, a controller for interactive communication with the power plant operation center is provided on the lower outer wall of the cylinder. The controller is electrically connected to the oxygen sensor, servo motor and electric push rod respectively.

[0022] Because the present invention employs the above-mentioned technology, its specific positive and beneficial effects compared with the prior art are as follows:

[0023] This invention addresses the issue of abnormal alarms triggered by oxygen sensors at a single location in an online oxygen monitoring system for power plant boilers. By remotely controlling the online oxygen calibration device at the power plant operation center, the system enables axial insertion / removal and radial switching of the oxygen sensors, improving the detection quality of the online oxygen monitoring system and facilitating timely and accurate calibration of the operating oxygen levels by the power plant operation center. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of an existing oxygen sensor installed on the outer wall of a flue.

[0025] Figure 2 This is a schematic diagram of the structure of the online oxygen content correction device for power plant boilers according to the present invention;

[0026] Figure 3 yes Figure 2 Top view of the structure shown;

[0027] Figure 4 yes Figure 3 Sectional view at point AA;

[0028] Figure 5 yes Figure 4 A three-dimensional sectional view of the structure shown;

[0029] Figure 6 yes Figure 5 A magnified view of a portion of point B in the middle;

[0030] Figure 7 yes Figures 2-5 The diagram shows the structure after the outer cylinder has been removed.

[0031] In the diagram: 1-outer wall of flue, 2-electric push rod, 3-cylinder body, 4-support, 5-connecting block, 6-end cover, 7-switching rod, 8-motor base, 9-servo motor, 10-support column, 11-main oxygen sensor, 12-standby oxygen sensor, 13-rotating shaft, 14-first support plate, 15-limiting baffle, 16-elastic locking seat, 17-oxygen sensor mounting base, 18-second support plate, 19-push rod seat, 20-sealing plate, 21-support ring, 22-nesting groove, 23-spring, 24-fixed cylinder, 25-locking block, 26-locking groove, 27-main flange interface. Detailed Implementation

[0032] Example 1:

[0033] like Figures 2-7As shown, this invention provides an online oxygen level correction device for power plant boilers, including an oxygen sensor, a cylinder 3, an end cap 6, a support column 10, a switching rod 7, an oxygen sensor mounting base 17, a servo motor 9, an electric push rod 2, and a rotating frame structure. The end of the cylinder 3 closest to the outer wall 1 of the flue is the bottom, and the end furthest from the outer wall 1 is the top. The top of the cylinder 3 is open and has an end cap 6. The bottom of the cylinder 3 has an external flange eccentrically located on the part furthest from the center for connecting to the main flange interface 27 on the outer wall 1 of the flue. The part of the cylinder 3 below the external flange has a support column 10 for abutting against the outer wall 1 of the flue. A rotating frame structure is provided inside the cylinder 3. A motor base 8 is provided on the end cap 6. The rotating frame structure is connected to the servo motor 9 on the motor base 8. Multiple oxygen sensors are evenly distributed on the rotating frame structure. Multiple oxygen sensors consist of a main oxygen sensor 11 and two or more backup oxygen sensors 12. The oxygen sensor inserted into the outer wall 1 of the flue is the main oxygen sensor 11, and the remaining oxygen sensors are backup oxygen sensors 12. The end of the oxygen sensor away from the outer wall 1 of the flue is provided with an oxygen sensor mounting seat 17. The oxygen sensor mounting seat 17 corresponding to the oxygen sensor coaxial with the external flange is abutted with a switching rod 7 for pushing the oxygen sensor out of the external flange. The switching rod 7 extends away from the outer wall 1 of the flue and is provided with a connecting block 5 at the end of the cylinder 3. The end of the connecting block 5 away from the switching rod 7 is provided with an electric push rod 2 located outside the cylinder 3. The end of the electric push rod 2 away from the connecting block 5 is provided on the push rod seat 19 at the bottom of the cylinder 3. The upper side of the outer wall of the cylinder 3 is provided with a support 4 for supporting the electric push rod 2.

[0034] Operating Mechanism: If an oxygen sensor at a single location in the online oxygen monitoring system for the power plant boiler malfunctions, the power plant operation center remotely controls the extension of the electric push rod 2. At this time, the switching rod 7, through the cooperation of the locking block 25 and the locking groove 26, drives the main oxygen sensor 11 to move towards the pull-out main flange interface 27. When the limiting baffle 15 of the oxygen sensor mounting base 17 corresponding to the main oxygen sensor 11 is embedded into the corresponding first through hole of the first support plate 14, and the oxygen sensor mounting base 17 corresponding to the main oxygen sensor 11 contacts the first support plate 14, the locking block 25 is forced to disengage from the locking groove 26 and elastically retracts into the corresponding fixed cylinder 24, thereby completing the connection between the switching rod 7 and the oxygen sensor. The separation action of the sensor mounting base 17 is the completion of the axial pull-out action of the oxygen sensor. Then, the servo motor 9 drives the rotating shaft 13 to rotate, so that multiple oxygen sensors complete radial switching. Finally, the electric push rod 2 retracts, and the switching rod 7 is re-inserted into the oxygen sensor mounting base 17 of the oxygen sensor that has completed radial switching. The switched oxygen sensor is inserted into the outer wall 1 of the flue. The switched oxygen sensor serves as the main oxygen sensor 11. This completes one oxygen sensor switching action, which is conducive to timely elimination of abnormal oxygen sensor faults, improves the operational stability of the existing online oxygen monitoring system for power plant boilers, and helps the power plant operation center to complete the accurate correction of the operating oxygen level in a timely manner.

[0035] The oxygen sensor mounting base 17 has a U-shaped structure and a rear through hole for the oxygen sensor to pass through at the end near the outer wall 1 of the flue. The flange of the oxygen sensor can be bolted around the rear through hole. A docking sleeve is provided on the side wall of the oxygen sensor mounting base 17 away from the rear through hole. A limiting baffle 15 is provided at the front end of the docking sleeve. Several elastic locking structures are provided on the outer wall of the docking sleeve. The elastic locking structures can be locked in the locking groove 26 at the end of the switching rod 7, so that the switching rod 7 can drive the oxygen sensor mounting base 17 to move away from the outer wall 1 of the flue.

[0036] The rotating frame structure includes a first support plate 14, a rotating shaft 13, and a second support plate 18. The end of the rotating shaft 13 away from the outer wall 1 of the flue is connected to a servo motor 9 outside the cylinder 3 and is driven to rotate by the servo motor 9. The end of the rotating shaft 13 away from the outer wall 1 of the flue is provided with the first support plate 14, and the end near the outer wall 1 of the flue is provided with the second support plate 18. Multiple oxygen sensors are evenly distributed between the first support plate 14 and the second support plate 18 with the center line of the rotating shaft 13 as the axis. The first support plate 14 is provided with a limiting baffle 15 corresponding to the oxygen sensor mounting base 17. There is a first through hole, and the second support plate 18 is provided with a second through hole corresponding to the oxygen sensor. Each second through hole is always nested in the corresponding oxygen sensor. The limiting baffle 15 of the oxygen sensor mounting base 17 corresponding to the main oxygen sensor 11 is separated from the corresponding first through hole. The limiting baffle 15 of the oxygen sensor mounting base 17 corresponding to the spare oxygen sensor 12 is embedded in the corresponding first through hole. The limiting baffle 15 of the end of the oxygen sensor near the outer wall 1 of the flue is embedded in the second support plate 18 and the end away from the outer wall 1 of the flue is embedded in the first support plate 14.

[0037] Since the second support plate 18 is always nested with each oxygen sensor, in order to improve the nesting stability of each oxygen sensor, a support ring 21 corresponding to the oxygen sensor is provided around the second through hole on the second support plate 18.

[0038] To ensure that the gas in the flue is unlikely to leak through the main flange interface 27 during the switching of the oxygen sensor, a sealing plate 20 made of high-temperature heat-insulating materials such as ceramic fiber board is provided on the end face of the second support plate 18 facing the outer wall 1 of the flue. The sealing plate 20 is also provided with the same second through hole as the second support plate 18. During the radial switching of the oxygen sensor, the sealing plate 20 blocks the port connecting the cylinder 3 and the main flange interface 27.

[0039] To facilitate wiring, the end of the rotating shaft 13 near the outer wall 1 of the flue is connected to the outside of the cylinder 3. The rotating shaft 13 adopts a hollow cylindrical structure and has several elongated holes evenly distributed on its side wall, which extend along its axis and are used for the oxygen sensor wires to extend into the rotating shaft 13. This allows the oxygen sensor wires to extend outward through the rotating shaft 13 and be electrically connected to the controller outside the cylinder 3.

[0040] The elastic locking structure includes an elastic locking seat 16, a spring 23, a fixed cylinder 24, and a locking block 25. The fixed cylinder 24 is fixedly installed on the outer wall of the docking sleeve and communicates with the inside of the docking sleeve. The elastic locking seat 16 is spirally nested on the fixed cylinder 24. The part of the elastic locking seat 16 facing the inside of the fixed cylinder 24 is provided with a spring 23. The end of the spring 23 extending inside the fixed cylinder 24 and facing the inside of the docking sleeve is provided with a locking block 25. The locking block 25 extends from the fixed cylinder 24 into the docking sleeve and can be embedded in the locking groove 26 on the end of the switching rod 7. During the extension of the electric push rod 2, the switching rod 7 drives the main oxygen sensor 11 to move towards the direction of pulling out the main flange interface 27 through the cooperation of the locking block 25 and the locking groove 26. After the radial switching of the oxygen sensor is completed, the switching rod 7 is reinserted into the oxygen sensor mounting seat 17 of the oxygen sensor that has completed the radial switching. The corresponding locking block 25 pops out elastically and is embedded in the locking groove 26 of the switching rod 7.

[0041] To facilitate wiring to the outside of the cylinder 3, a through hole is provided on the end face of the oxygen sensor mounting base 17 facing the axis of the rotating frame structure for the wires of the oxygen sensor to pass through.

[0042] In order to receive the detection data of the main oxygen sensor 11 and control the servo motor 9 and the electric push rod 2 to perform corresponding actions, a PLC controller for interactive communication with the power plant operation center is provided on the lower outer wall of the cylinder 3. The PLC controller is electrically connected to the oxygen sensor, the servo motor 9 and the electric push rod 2 respectively.

[0043] Corresponding to the online oxygen content correction device for power plant boilers, this invention also provides an online oxygen content correction method for power plant boilers, comprising the following steps:

[0044] S1. In response to an abnormal alarm of an oxygen sensor at a single location in the online oxygen monitoring system for power plant boiler operation, the electric push rod 2 in the online oxygen correction device for power plant boiler operation is moved away from the outer wall 1 of the flue by remote control of the power plant operation center. The switching rod 7 connected to the electric push rod 2 is driven to move away from the outer wall 1 of the flue, so that the abnormal oxygen sensor exits from the flue.

[0045] S2. The servo motor 9 in the online oxygen correction device for the boiler operation of the power plant is remotely controlled by the power plant operation center to drive the rotating frame structure to rotate clockwise until the other oxygen sensors on the rotating frame structure are concentric with the main flange interface 27 on the outer wall of the flue duct 1.

[0046] S3. The electric push rod 2 in the online oxygen correction device for the boiler operation of the power plant is retracted by the remote control of the power plant operation center, and the switching rod 7 is moved towards the outer wall 1 of the flue until the switched oxygen sensor is pushed into the main flange interface 27 on the outer wall 1 of the flue by the switching rod 7.

[0047] S4. If the operating oxygen level detected by the switched oxygen sensor is equal to the operating oxygen level detected by the oxygen sensor before the switch, stop the operation of the online oxygen level calibration device for the power plant boiler and investigate other causes; if the operating oxygen level detected by the switched oxygen sensor is not equal to the operating oxygen level detected by the oxygen sensor before the switch, repeat steps S1-S3 again, switch the oxygen sensor again, and compare the operating oxygen level detection data of the oxygen sensor after the first switch with that of the second switch.

[0048] S5. If the operating oxygen value of the oxygen sensor after the first switch is equal to that of the oxygen sensor after the second switch, then follow steps S1-S3 again. In step S2, the servo motor 9 in the online oxygen calibration device for the power plant boiler is remotely controlled by the power plant operation center to drive the rotating frame structure to rotate counterclockwise, switching back to the oxygen sensor after the first switch. If the operating oxygen value of the oxygen sensor after the first switch is not equal to that of the oxygen sensor after the second switch, then stop the operation of the online oxygen calibration device for the power plant boiler and investigate other causes.

Claims

1. An online oxygen level correction device for power plant boiler operation, comprising an oxygen sensor, characterized in that: It also includes a cylinder, support columns, a switching rod, an oxygen sensor mounting base, a servo motor, an electric push rod, and a rotating frame structure. On the end face of the cylinder near the outer wall of the flue, a portion away from the center of the end face has an external flange for connecting to the main flange interface on the outer wall of the flue. A support column is located on the part of the cylinder below the external flange for abutting against the outer wall of the flue. A rotating frame structure is installed inside the cylinder, and this rotating frame structure is connected to a servo motor on the end of the cylinder away from the outer wall of the flue. Multiple oxygen sensors are evenly distributed on the rotating frame structure, and each oxygen sensor has an oxygen sensor mounting base at its end away from the outer wall of the flue, which connects to the external flange. The oxygen sensor mounting base corresponding to the coaxial oxygen sensor has a switching rod attached to it for pushing the oxygen sensor out of the external flange. The switching rod extends away from the outer wall of the flue and has a connecting block at its end extending outward from the cylinder. An electric push rod is located on the outside of the cylinder at the end of the connecting block away from the switching rod. The oxygen sensor mounting base has a U-shaped structure, and a rear through hole for the oxygen sensor to pass through is located at the end near the outer wall of the flue. The flange of the oxygen sensor can be bolted around the rear through hole. A docking sleeve is provided on the side wall of the oxygen sensor mounting base away from the rear through hole. A limiting baffle is provided at the front end of the docking sleeve. The outer wall of the docking sleeve is provided with several elastic locking structures. These structures can engage with locking grooves on the end of the switching rod, allowing the switching rod to move the oxygen sensor mounting base away from the outer wall of the flue. Each elastic locking structure includes an elastic locking seat, a spring, a fixed cylinder, and a locking block. The fixed cylinder is fixedly mounted on the outer wall of the docking sleeve and communicates with its interior. An elastic locking seat is spirally nested on the fixed cylinder. A spring is provided on the portion of the elastic locking seat facing inwards from the fixed cylinder. A locking block is provided at the end of the spring extending inside the fixed cylinder and facing inwards from the docking sleeve. The locking block is secured by a fixed... The cylinder extends into the docking sleeve and can be embedded in the locking groove on the end of the switching rod. The rotating frame structure includes a first support plate, a rotating shaft, and a second support plate. The end of the rotating shaft away from the outer wall of the flue is connected to a servo motor outside the cylinder and is driven to rotate by the servo motor. The end of the rotating shaft away from the outer wall of the flue is provided with a first support plate, and the end near the outer wall of the flue is provided with a second support plate. Multiple oxygen sensors are evenly distributed between the first and second support plates with the center line of the rotating shaft as the axis. The end of the oxygen sensor near the outer wall of the flue is embedded in the second support plate, and the limiting baffle on the end away from the outer wall of the flue is embedded in the first support plate.

2. The online oxygen content correction device for power plant boilers according to claim 1, characterized in that: The oxygen sensor mounting base has a through hole on its end face facing the axis of the rotating frame structure for the oxygen sensor wires to pass through.

3. The online oxygen content correction device for power plant boilers according to claim 1, characterized in that: The end of the rotating shaft near the outer wall of the flue is connected to the outside of the cylinder. The rotating shaft adopts a hollow cylindrical structure and has several elongated holes evenly distributed on its side wall, which extend along its axis and are used for the wires of the oxygen sensor to extend into the rotating shaft, so that the wires of the oxygen sensor extend outward through the rotating shaft and are electrically connected to the controller outside the cylinder.

4. The online oxygen content correction device for power plant boilers according to claim 3, characterized in that: The second support plate has a sealing plate made of high-temperature resistant heat insulation material on its end face facing the outer wall of the flue.

5. The online oxygen content correction device for power plant boilers according to claim 4, characterized in that: The lower outer wall of the cylinder is equipped with a controller for interactive communication with the power plant operation center. The controller is electrically connected to the oxygen sensor, servo motor and electric push rod respectively.

6. A method for online correction of oxygen levels in power plant boilers, characterized in that: The online oxygen content correction device for power plant boilers according to any one of claims 1-5 includes the following steps: S1. In response to an abnormal alarm caused by an oxygen sensor at a single location in the online oxygen monitoring system for power plant boiler operation, the power plant operation center remotely controls the electric push rod in the online oxygen correction device for power plant boiler operation to move away from the outer wall of the flue. The switching rod connected to the electric push rod moves away from the outer wall of the flue, causing the abnormal oxygen sensor to exit from the flue. During the exit process, the switching rod engages with the locking block on the oxygen sensor mounting base through the locking groove at its end, causing the oxygen sensor to move axially. When the oxygen sensor moves to the set pull-out position, the locking block contracts under force and automatically disengages from the locking groove, realizing the automatic separation of the switching rod from the oxygen sensor mounting base. S2. The servo motor in the online oxygen correction device for the boiler operation of the power plant is remotely controlled by the power plant operation center to drive the rotating frame structure to rotate clockwise until the other oxygen sensors on the rotating frame structure are concentric with the main flange interface on the outer wall of the flue. S3. The electric push rod in the online oxygen correction device for the power plant boiler is retracted by the remote control of the power plant operation center. The switching rod moves towards the outer wall of the flue until the switched oxygen sensor is pushed into the main flange interface on the outer wall of the flue by the switching rod. The switching rod is then reinserted into the oxygen sensor mounting seat corresponding to the switched oxygen sensor. The locking block pops out elastically and is re-embedded into the locking groove to achieve the re-locking and pushing action. S4. If the operating oxygen level detected by the switched oxygen sensor is equal to the operating oxygen level detected by the oxygen sensor before the switch, then stop the operation of the power plant boiler operating oxygen level online correction device and investigate other causes; if the operating oxygen level detected by the switched oxygen sensor is not equal to the operating oxygen level detected by the oxygen sensor before the switch, then repeat steps S1-S3 again, switch the oxygen sensor again, and compare the operating oxygen level detection data of the oxygen sensor after the first switch with that of the oxygen sensor after the second switch. S5. If the operating oxygen value of the oxygen sensor after the first switch is equal to that of the oxygen sensor after the second switch, then follow steps S1-S3 again. In step S2, the servo motor in the online oxygen calibration device for the power plant boiler is remotely controlled by the power plant operation center to drive the rotating frame structure to rotate counterclockwise, switching back to the oxygen sensor after the first switch. If the operating oxygen value of the oxygen sensor after the first switch is not equal to that of the oxygen sensor after the second switch, then stop the operation of the online oxygen calibration device for the power plant boiler and investigate other causes.

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