A device and method for monitoring the failure of a damper pull rod of a pulverized coal burner

Abstract

The application discloses a kind of coal powder burner damper pull rod fault monitoring device and method.The application includes tension sensor, damper pull rod, damper air adjusting disc, electric actuator, tension signal line, current sensor, control system, wind box, wind box wall.Utilize the tension sensor connected with damper connecting rod, when electric actuator acts, the change of connecting rod tension is detected in real time, simultaneously utilize current sensor to detect the change of electric actuator current value, utilize current value and tension value and its mutual relation, the fracture fault of damper pull rod is diagnosed in real time, simultaneously damper system's jamming fault can also be diagnosed and the position of jamming is clear.The application does not need to stop furnace to enter wind box and check damper connecting rod condition, the health status of damper system is diagnosed in real time in operation, and the reliability of equipment operation is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of equipment fault monitoring technology in coal-fired power plants, and relates to a fault monitoring device and method for damper rods of pulverized coal burners. Background Technology

[0002] Swirl-flow pulverized coal burners are one of the mainstream types of pulverized coal burners in boilers. The performance of these burners significantly impacts combustion stability, economy, safety, and pollutant emissions. The control of the damper plays a decisive role in burner performance: it controls the airflow to deliver fuel and the necessary combustion air into the furnace, creating a favorable aerodynamic field that allows for rapid and stable ignition; it ensures timely air supply and proper mixing with fuel for complete combustion; it adapts well to different coal types and load requirements, exhibiting good adjustability and a wide adjustment range; and it controls NOx generation within environmentally permissible limits. Continuous and stable ignition, intense combustion, and complete burnout of pulverized coal in the furnace all depend on the distribution and regulation of primary and secondary air. Therefore, accurate damper control is a fundamental requirement for pulverized coal combustion in power plant boilers.

[0003] To ensure optimal combustion performance in the boiler, the proper functioning of the pulverized coal burner damper regulation system is essential. However, during daily operation, each burner damper operates in a high-temperature, dusty environment. Furthermore, when airflow demand is high, duct vibration may intensify. Over time, components of the damper actuator, exposed to harsh conditions, may experience aging, mechanical jamming, or broken rods. Especially since components like the rods are located inside the air box, these malfunctions are difficult to detect immediately. Failure to promptly identify and address pulverized coal burner damper malfunctions will directly impact the boiler's combustion status and emissions, failing to meet environmental protection requirements for real-time online monitoring of power plant emissions. This may even necessitate shutdowns for maintenance, impacting the power plant's economic efficiency to some extent. For example, a 1050MW front and rear wall opposed combustion unit had problems such as slagging in the furnace, excessive wall temperature of the heating surface, and serious deviation of steam temperature on both sides for a long time, which led to a decrease in load-carrying and variable load capacity. The problem could not be solved by hot adjustment. Only after shutting down the furnace and carrying out cold test did it find that the secondary air damper connecting rod of one of the burners was broken, causing the secondary air damper to be in the closed state.

[0004] Current pulverized coal burner damper regulation systems only have the basic function of controlling the damper opening, and the damper opening value is only fed back through the status of external actuators. They lack fault monitoring and diagnostic capabilities. Therefore, developing a fault monitoring device and method for pulverized coal burner damper levers has significant practical importance and application value. Summary of the Invention

[0005] The purpose of this invention is to provide a device and method for monitoring the faults of pulverized coal burner damper rods, in order to prevent operational safety risks and economic losses in power plants caused by burner damper malfunctions. This device can monitor whether the damper rod has performed effective action during operation, determine whether the burner damper rod is stuck or broken, and promptly detect any faults in the pulverized coal burner damper rod, thus avoiding economic losses to the power plant caused by such faults.

[0006] The basic principle of this invention is: in order to detect faults caused by the damper actuator in a timely manner, the actual working status of the damper rod is monitored in real time by combining the damper rod with tension sensor technology and using a fault-tolerant method that combines changes in linkage tension and changes in actuator current.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] This invention includes a tension sensor, a damper rod, a damper regulating disc, an electric actuator, a tension signal line, a current sensor, a control system, and a bellows;

[0009] The tension sensor is an S-type tension sensor, which is connected to the damper rod and the damper regulating plate through the internal threaded holes at both ends, respectively; and since it is in a high-temperature environment inside the air box, a tension sensor with a temperature resistance of 350℃ or higher must be selected.

[0010] The damper rod is made of stainless steel tube with an external threaded interface at one end, which is used to connect to the tension sensor, and the other end is connected to the electric actuator.

[0011] The tension signal line outputs the tension signal from the tension sensor to the control system. Since the tension sensor is located between the damper pull rod and the damper regulating plate, the tension signal line must be able to withstand temperatures above 330°C and be placed inside an anti-wear sleeve.

[0012] The current sensor is used to detect the current during the operation of the electric actuator.

[0013] Furthermore, if the tension sensor cannot meet the high temperature resistance requirements, a conventional tension sensor will be selected. In this case, the conventional tension sensor needs to be placed between the damper rod outside the air box and the electric actuator.

[0014] Furthermore, if the tension sensor is located outside the air box, the damper rod is connected to the damper regulating plate, and the damper rod is connected to the electric actuator through a conventional tension sensor.

[0015] Furthermore, the aforementioned damper / air regulating plate is an existing airflow regulating device for the burner. The aforementioned electric actuator is also an existing device.

[0016] Furthermore, when the burner damper uses a pneumatic actuator, there is no need to install a current sensor.

[0017] The fault detection method of the device of the present invention is implemented as follows:

[0018] The tension signal from the tension sensor and the current signal from the electric actuator are fed into the DCS system and collected in real time. The DCS system diagnoses the action of the damper lever based on the changes in the tension and current signals. Once the burner is confirmed to be operating normally, the normal range of tension and current values ​​is established.

[0019] (1) No diagnosis is performed when the current is zero;

[0020] (2) When the current value is less than or equal to the normal value range, if the tension value is within the normal value range, the damper rod is normal. If the tension value is less than the lower limit of the normal value, it indicates that the rod may break.

[0021] (3) When the current value is greater than the normal range and the tension sensor is placed inside the air box, if the tension value is less than or equal to the normal range, it indicates that the damper rod may be stuck to the air box wall. If the tension value is greater than the normal range, it indicates that the damper regulating plate may be stuck. When the current value is greater than the normal range and the tension sensor is placed outside the air box, if the tension value is greater than the normal range, it indicates that the damper rod may be stuck to both the air box wall and the damper regulating plate.

[0022] (4) If a pneumatic actuator is used, the change in the opening of the actuator is used to determine whether the damper is in operation. If the pulling force is less than the normal range when the damper is in operation, it indicates that the damper rod may break.

[0023] The advantage of placing the tension sensor between the damper rod and the damper regulating disc is that it can more effectively detect and diagnose the actuating traction force of the damper regulating disc, avoiding misdiagnosis caused by possible jamming between the damper rod and the air box wall. If the tension sensor's high temperature resistance and dustproof capability are insufficient, it can also be installed on the connection end between the damper rod and the electric actuator outside the air box. In this case, a breakage fault of the damper rod can be diagnosed, but if a jamming fault occurs in the damper regulating system, it is difficult to determine the specific location.

[0024] The aforementioned tension sensor can also adopt other structural forms that are easy to install and use, and its connection method with other components can be adjusted accordingly.

[0025] Compared with existing burner damper linkages, the advantages of this invention are as follows:

[0026] This invention utilizes a tension sensor connected to the damper linkage to detect changes in linkage tension in real time during the operation of the electric actuator. Simultaneously, a current sensor detects changes in the electric actuator's current value. By analyzing the current and tension values ​​and their interrelationship, the invention can diagnose damper linkage fracture faults in real time, as well as damper system jamming faults and pinpoint the location of the jamming. This invention eliminates the need to shut down the furnace and enter the windbox to inspect the damper linkage. During operation, it diagnoses damper linkage faults in real time by monitoring the damper linkage tension and the electric actuator's current value, and can also simultaneously diagnose equipment jamming faults, effectively improving the reliability of equipment operation. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of a coal pulverizer damper rod fault monitoring device and method provided by the present invention.

[0028] In the diagram, 1 is the tension sensor, 2 is the damper lever, 3 is the damper regulating disc, 4 is the electric actuator, 5 is the tension signal line, 6 is the current sensor, 7 is the control system, 8 is the air box, and 9 is the air box wall. Detailed Implementation

[0029] The implementation of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] like Figure 1 As shown, the present invention provides a fault monitoring device for a pulverized coal burner damper rod, comprising a tension sensor 1, a damper rod 2, a damper regulating disc 3, an electric actuator 4, a tension signal line 5, a current sensor 6, a control system 7, a wind box 8, and a wind box wall 9.

[0031] The tension sensor 1 is an S-type tension sensor, connected to the damper rod 2 and the damper regulating plate 3 respectively through internal threaded holes at both ends. Since the tension sensor 1 operates in a high-temperature, high-dust environment above 330℃, a high-temperature resistant and dustproof tension sensor is required. If the tension sensor 1 lacks sufficient high-temperature resistance and dustproof capabilities, it can also be installed outside the air box between the damper rod 2 and the electric actuator 4.

[0032] The tension sensor 1 can also adopt other structural forms that are easy to install and use, and the connection method between the tension sensor 1 and other components can be adjusted accordingly.

[0033] The damper rod 2 is a stainless steel tube with an external threaded interface at one end, which is used to connect to the tension sensor 1. The other end is connected to the electric actuator 4. If the tension sensor 1 is located outside the air box 8, the damper rod 2 is connected to the damper regulating plate 3. The connection method between the damper rod 2 and the electric actuator 4 or the damper regulating plate 3 can be designed as needed.

[0034] The tension signal line 5 outputs the tension signal from the tension sensor to the control system 7. If the tension sensor 1 is arranged between the damper rod 2 and the damper regulating plate 3, the tension signal line 5 must have the ability to withstand high temperatures above 330℃ and be arranged inside the wear-resistant sleeve.

[0035] The current sensor 6 is installed on the power line of the electric actuator 4 to detect the current during the operation of the electric actuator 4. It is generally a current transformer, but other types of sensors that meet the current detection requirements can also be used. If the burner damper uses a pneumatic actuator, then the current sensor 6 is not required.

[0036] The control system mentioned is an existing control system, such as a power plant DCS system.

[0037] The aforementioned bellows is an existing component of the boiler.

[0038] The bellows wall mentioned above is the outer wall of the bellows.

[0039] The aforementioned damper and air regulating plate are existing air volume regulating devices for burners. The air volume regulation methods for different models of burners may differ, such as using sleeve dampers, but the transmission methods are basically the same, and this invention is equally applicable.

[0040] The tension sensor has a sensor signal output line in the middle, which is used to convert the force signal into an electrical signal and output it to the DCS control system.

[0041] A fault detection method for a pulverized coal burner damper rod fault monitoring device is specifically implemented as follows:

[0042] The system collects tension signals from the tension sensor and current signals from the electric actuator in real time and transmits them to the DCS system. The DCS system diagnoses the operation of the damper lever based on changes in the tension and current signals. Due to potential differences in the manufacturing and installation of different burners, as well as varying degrees of deformation after operation, the reference values ​​for tension and current may differ between different burners.

[0043] Once the burner is confirmed to be operating normally, establish the normal range of tension and current values.

[0044] (1) No diagnosis is performed when the current is zero.

[0045] (2) When the current value is less than or equal to the normal value range, if the tension value is within the normal value range, the damper rod is normal. If the tension value is less than the lower limit of the normal value, it indicates that the rod may break.

[0046] (3) When the current value is greater than the normal range, and the tension sensor is located inside the air box, if the tension value is less than or equal to the normal range, it indicates that the damper rod may be stuck to the air box wall. If the tension value is greater than the normal range, it indicates that the damper regulating plate may be stuck. When the current value is greater than the normal range, and the tension sensor is located outside the air box, if the tension value is greater than the normal range, it indicates that the damper rod may be stuck to both the air box wall and the damper regulating plate.

[0047] If a pneumatic actuator is used (the same applies to electric actuators if no current sensor is installed), the change in the actuator's opening degree is used to determine whether the damper is operating. If the damper is operating and the pulling force is less than the normal range, it indicates that the damper rod may be broken.

[0048] The pulverized coal burner damper rod fault monitoring device and method provided by this invention adds a tension monitoring device to the existing burner damper rod in coal-fired power plants. It monitors the actual working status of the damper rod during operation by using a fault-tolerant method that combines tension changes from a tension sensor with current changes from the actuator. Operators only need to monitor the stress on the damper rod in real time on the control system to determine if a fault exists. This device effectively simplifies the cumbersome fault diagnosis process and avoids safety problems or economic losses caused by untimely detection of damper faults in coal-fired power plants.

[0049] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A fault monitoring device for a pulverized coal burner damper rod, characterized in that... Includes tension sensor, damper lever, damper air regulating disc, electric actuator, tension signal line, current sensor, control system, and air box; The tension sensor is an S-type tension sensor, which is connected to the damper rod and the damper regulating plate through the internal threaded holes at both ends, respectively; and since it is in a high-temperature environment inside the air box, a tension sensor with a temperature resistance of 350℃ or higher must be selected. The damper rod is made of stainless steel tube with an external threaded interface at one end, which is used to connect to the tension sensor, and the other end is connected to the electric actuator. The aforementioned damper and air regulating plate are existing air volume regulating devices for the burner; The tension signal line outputs the tension signal from the tension sensor to the control system. Since the tension sensor is located between the damper pull rod and the damper regulating plate, the tension signal line must be able to withstand temperatures above 330°C and be placed inside an anti-wear sleeve. The current sensor is used to detect the current when the electric actuator is running, when the burner damper uses a pneumatic actuator; If the tension sensor cannot meet the high temperature resistance requirements, a conventional tension sensor shall be selected. In this case, the conventional tension sensor needs to be placed between the damper rod and the electric actuator outside the air box, and the damper rod is directly connected to the damper regulating plate. The fault detection method of this device is implemented as follows: The tension signal from the tension sensor and the current signal from the electric actuator are fed into the DCS system and collected in real time. The DCS system diagnoses the action of the damper lever based on the changes in the tension and current signals. Once the burner is confirmed to be operating normally, the normal range of tension and current values ​​is established. (1) No diagnosis is performed when the current is zero; (2) When the current value is less than or equal to the normal value range, if the tension value is within the normal value range, the damper rod is normal. If the tension value is less than the lower limit of the normal value, it indicates that the rod may break. (3) When the current value is greater than the normal range and the tension sensor is placed inside the air box, if the tension value is less than or equal to the normal range, it indicates that the damper rod may be stuck to the air box wall. If the tension value is greater than the normal range, it indicates that the damper regulating plate may be stuck. When the current value is greater than the normal range and the tension sensor is placed outside the air box, if the tension value is greater than the normal range, it indicates that the damper rod may be stuck to both the air box wall and the damper regulating plate. (4) If a pneumatic actuator is used, the change in the opening of the actuator is used to determine whether the damper is in operation. If the pulling force is less than the normal range when the damper is in operation, it indicates that the damper rod may break.

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