Monitoring and early warning system for dust hopper structure of dust remover

Abstract

The utility model discloses a monitoring and early warning system for a dust hopper structure of a dust remover. The monitoring and early warning system comprises a fiber grating sensor, a fiber grating demodulator, a router, a converter and an industrial personal computer, wherein the fiber bragg grating sensor comprises a fiber bragg grating strain sensor and a fiber bragg grating temperature sensor; an optical signal collected by the fiber grating sensor is transmitted to the fiber grating demodulator through an optical cable; the industrial personal computer judges the stress state of the ash bucket in time based on real-time monitoring data and gives an alarm for abnormal conditions; the router is responsible for transmitting the data of each fiber bragg grating demodulator to an industrial personal computer of a dust removal room, or respectively transmitting the integrated data to DCS system servers of different units of a central control room; the converter is responsible for photoelectric signal conversion in the transmission process. The dust hopper structure stress and the dust level are monitored in real time, and dust removal measures are taken according to stress alarm information so as to ensure the safety of the dust hopper.

Description

Technical Field

[0001] This utility model relates to the field of dust collector hopper monitoring technology, and in particular to a monitoring and early warning system for a dust collector hopper structure. Background Technology

[0002] Below the dust collector is an ash hopper to collect ash from the flue gas. Most dust collector ash hoppers are pyramidal in shape, with the steel structure mainly consisting of hopper wall panels, stiffening ribs, and pipe supports. The hopper is wider at the top and narrower at the bottom, with a height of 6m-9m. The larger opening of the hopper connects to the bottom beam of the casing, while the smaller opening connects to the vulcanizing equipment or ash conveying equipment. The load inside the ash hopper is uneven. During unit operation, the system pressure inside the ash hopper is approximately 3kPa, and the temperature reaches approximately 160℃, making it impossible to directly observe the ash in the hopper. The ash hopper is generally equipped with two level gauges (high and low), wall temperature measuring points, and a negative pressure sampling device to monitor its operating status. Under normal circumstances, there is a certain amount of ash in the ash hopper; too much ash will cause the hopper to overload, while too little ash will result in insufficient output from the ash conveying equipment, wasting energy. Therefore, it is necessary to reliably monitor the ash level in the ash hopper to ensure that the ash level is controlled at a suitable position, and to prevent the ash level in the ash hopper from being too high, which could lead to overload and collapse of the ash hopper or collapse of the entire dust collector. This is very important for the safety of the dust collector ash hopper.

[0003] Traditional methods for monitoring the status of ash hoppers primarily rely on level gauges. Mechanical and capacitive level gauges, which require insertion into the ash hopper, are prone to malfunction. Repairs and replacements necessitate stopping the machine and emptying the hopper. Furthermore, capacitive level gauges are prone to false alarms due to ash buildup. Passive nuclear level gauges suffer from inaccurate measurements due to coal type variations, inability to remotely alarm during malfunctions, failure to alarm due to the physical phenomenon of "piled material radiation attenuation," and inability to perform calibration and setting procedures. Therefore, most passive nuclear level gauges exhibit low reliability and numerous problems.

[0004] Aside from material level displays, there are no other effective technical measures for each ash hopper of the dust collector. The technical measures to prevent the dust collector from collapsing are relatively simple and passive, and their effectiveness is poor.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the general background of this utility model and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Utility Model Content

[0006] The purpose of this utility model is to provide a monitoring and early warning system for the dust collector hopper structure to solve the technical problems existing in the prior art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This utility model provides a monitoring and early warning system for the dust collector hopper structure, comprising: a fiber Bragg grating sensor, a fiber Bragg grating demodulator, a router, a converter, and an industrial control computer; wherein...

[0009] The fiber optic grating sensor includes a fiber optic grating strain sensor and a fiber optic grating temperature sensor. The fiber optic grating strain sensor is used to collect strain information of the ash hopper in real time, and the fiber optic grating temperature sensor is used to perform temperature compensation on the fiber optic grating strain sensor.

[0010] The optical signal collected by the fiber Bragg grating sensor is transmitted to the fiber Bragg grating demodulator via optical cable. The fiber Bragg grating demodulator demodulates the wavelength offset and transmits it to the industrial control computer in the ash removal control room.

[0011] The industrial control computer promptly judges the stress state of the ash hopper based on real-time monitoring data and issues alarms for abnormal situations.

[0012] The router is responsible for transmitting data from each fiber Bragg grating demodulator to the industrial control computer in the dust removal room, or transmitting the integrated data to the DCS system servers of different units in the central control room; the converter is responsible for the conversion of photoelectric signals during transmission.

[0013] Furthermore, the fiber Bragg grating sensors are deployed on the dust collector hopper wall panel and stiffening ribs; eight fiber Bragg grating strain sensors are deployed, with measuring points numbered #1, #2, #3, #5, #6, #7, #9, and #10; two fiber Bragg grating temperature sensors are deployed, with measuring points numbered #4 and #8; all fiber Bragg grating sensors are connected in series to the fiber Bragg grating demodulator and the industrial control computer.

[0014] Furthermore, the fiber optic grating sensor is a spot-welded sensor, which is welded to the ash hopper using a spot welding machine; then a protective cover is installed, which is welded to the surface and the outside of the strain gauge to prevent external extrusion and deformation; and a corresponding number label is affixed to the end of the sensor wire.

[0015] By adopting the above technical solution, this utility model has the following beneficial effects:

[0016] This application enables real-time monitoring of the stress and ash level in the ash hopper structure, and takes ash removal measures based on stress alarm information to ensure the safety of the ash hopper. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 An overall structural block diagram of the monitoring and early warning system for the dust collector hopper structure provided in this embodiment of the utility model;

[0019] Figure 2 A schematic diagram of the fiber optic grating sensor layout on the dust collector hopper provided in this embodiment of the utility model.

[0020] Figure 3 The strain time history curve acquired by the fiber optic grating sensor provided in this embodiment of the utility model;

[0021] Figure 4 The strain time history curve acquired by the resistance strain gauge provided in this embodiment of the utility model;

[0022] Figure 5 Temperature-compensated strain time history curves provided for embodiments of this utility model;

[0023] Figure 6 The strain time history curve of measuring point #1 provided in this embodiment of the utility model;

[0024] Figure 7 The strain time history curve of measuring point #3 provided in this embodiment of the utility model;

[0025] Figure 8 The strain time history curve of measuring point #5 provided in this embodiment of the utility model;

[0026] Figure 9 The strain time history curve of measuring point #7 provided for the embodiment of this utility model. Detailed Implementation

[0027] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0028] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0029] Combination Figure 1As shown, this embodiment provides a monitoring and early warning system for the dust collector hopper structure, which includes fiber Bragg grating sensors, fiber Bragg grating demodulators, routers, converters, and an industrial control computer. The fiber Bragg grating sensors include fiber Bragg grating strain sensors and fiber Bragg grating temperature sensors. The fiber Bragg grating strain sensor is used to collect hopper strain information in real time, and the fiber Bragg grating temperature sensor is used for temperature compensation of the strain sensor. The optical signal collected by the fiber Bragg grating sensor is transmitted to the fiber Bragg grating demodulator via optical cable. The fiber Bragg grating demodulator demodulates the wavelength offset and transmits it to the industrial control computer in the dust removal control room. The industrial control computer includes intelligent applications such as data query, data analysis, alarm, and data interface. Based on real-time monitoring data, it promptly judges the stress state of the hopper and issues alarms for abnormal conditions. The router is responsible for transmitting data from each fiber Bragg grating demodulator to the industrial control computer in the dust removal room, or transmitting the integrated data separately to the DCS system servers of different units in the central control room. The converter is responsible for converting photoelectric signals during transmission.

[0030] The software component of the fiber Bragg grating hopper strain monitoring system used in this application is developed based on KingView software. This software is feature-rich and can realize various commonly used functions such as online analysis of strain at monitoring points, data storage, alarm value setting, and management.

[0031] The software system mainly includes: real-time display, sensor management, stress analysis, data management, and alarm modules. The real-time display module includes the stress at the monitoring point, the stress curve at the monitoring point, and the gray level height; sensor management includes sensor parameter settings, sensor data processing formulas, and alarm value settings; the stress analysis module provides real-time analysis of the strain values ​​at the monitoring point; the data management module includes data extraction and data storage; and the alarm module includes alarm notification management and alarm log management.

[0032] Combination Figure 2 As shown, the fiber Bragg grating sensors in this application are arranged on the dust collector hopper wall panel and stiffening ribs; eight fiber Bragg grating strain sensors are arranged, with measuring points numbered #1, #2, #3, #5, #6, #7, #9 and #10; two fiber Bragg grating temperature sensors are arranged, with measuring points numbered #4 and #8; all fiber Bragg grating sensors are connected in series to the fiber Bragg grating demodulator and the industrial control computer.

[0033] The sensors used in this application are spot-welded sensors, suitable for health monitoring of steel structures and easy to install. Upon receiving the sensors, they were tested to ensure readings were within normal ranges. Before welding, the insulation layer of the ash hopper was partially removed, and the welding points on the ash hopper surface were marked. The coating at the bonding location was sanded off, and the surface was wiped smooth with alcohol. The sensor's position and angle were adjusted, and the sensor was spot-welded to the ash hopper using a spot welding machine. A protective cover was then installed to prevent sensor damage. The protective cover was welded to the surface and the outside of the strain gauge to prevent external deformation. After the sensors were installed, corresponding numbered labels were affixed to the ends of the cables for easy connection to the data acquisition instrument. The fiber optic cables between sensors should be connected and lengthened according to site conditions. Changes in cable length will not affect the frequency of the sensor output signal and have no impact on the acquired data values. Readings were checked using testing instruments to eliminate any abnormalities. The performance parameters of the fiber optic grating sensor are shown in the table below.

[0034]

[0035] To verify the specific application effect of this application, after the fiber optic grating sensor was installed, the applicant first conducted a test on the monitoring system. The strain data of the resistance strain gauge and the fiber optic grating sensor were compared and analyzed. At the same time, it was verified that there was no problem with the sensor circuit of the monitoring system. The test process was during the ash unloading stage of the ash hopper, and the ash level was about the eighth rib of the ash hopper (from top to bottom).

[0036] The test was conducted from 23:06 on November 1st to 18:06 on November 2nd, 2023, for a total of 19 hours. The fiber optic demodulator's sampling frequency was 10 Hz, theoretically requiring 684,000 data points. The actual number of samples collected was 684,252, resulting in a sampling rate of 100.03%, indicating good real-time monitoring. After the test period, the test system revealed that the optical cables at positions #1 and #3 were compressed, causing data anomalies. Therefore, no test data was collected for positions #1 and #3 during the test. The remaining data generally met the test requirements.

[0037] Depend on Figure 3 , Figure 4 It can be seen that, after 19 hours of testing, the strain of both the fiber optic grating sensor and the resistance strain gauge changed significantly with the decrease in ash height. Furthermore, the strain-time history curves of both testing methods showed consistent trends under the same load location. The initial strain change was caused by the decrease in ash load, while the later strain change was caused by changes in dust collector pressure. The peak stresses of the two testing methods are listed in the table. The peak stresses are basically consistent, but there is still some error. The main reason for the discrepancy is that the two sensors are not completely aligned at the same measuring point, and the placement of the temperature compensation gauge also differs.

[0038] Measuring points #5 and #9 are located at the middle and end of the stiffening rib at the same height. Measuring point #5 measures tensile strain, and measuring point #9 measures tensile strain, which is consistent with the stress characteristics of the stiffening rib. Tests confirm that the fiber optic grating sensor can sensitively reflect the real-time data of the corresponding measuring points. Preliminary data acquisition and analysis can be performed using monitoring software. Comparing the data from both methods reveals that the data acquired by the fiber optic grating sensor exhibits less fluctuation, indicating that the fiber optic grating sensor has better stability and superior performance in this environment. This demonstrates the feasibility of applying fiber optic grating sensing monitoring to the health monitoring of ash hopper structures.

[0039] The applicant monitored and analyzed the strain operation of the ash hopper, as detailed below:

[0040] During the testing of the optical cables at positions #1 and #3, it was found that compression caused abnormal data. After the test was completed, the compressed positions were cleaned up, and the sensors #1 and #3 were restored to normal operation.

[0041] The data collected from 06:48 on November 2nd to 03:49 on November 10th will be extracted and analyzed. Figure 5 The data collected using temperature-compensated sensors was used to compensate for strain data at corresponding measuring points. The strain at each measuring point fluctuated over 24 hours, indicating that the ash hopper is mainly affected by ambient temperature, with smaller fluctuations at the temperature generated by flue gas, ash, and steam heating. Because the measuring points are located at different locations, there are temperature differences between them, resulting in some degree of variation in strain, but the overall trend is consistent.

[0042] Figures 5 to 9 The strain changes at the fiber Bragg grating sensor deployment locations after temperature compensation are shown. The table below provides... Figures 5 to 9 The maximum and minimum strains collected show that the maximum strain is 335.46 µε at position #3. The calculated stress is 67.09 MPa, which is less than the allowable stress of 235 MPa for the ash hopper material. During the monitoring period, the ash volume in the ash hopper was relatively small, and the ash level did not reach the height of the measuring point. The strain change was caused by the negative pressure and temperature changes of the dust collector, indicating that the ash hopper was in a safe state under normal operation of the ash conveying system.

[0043]

[0044] After research, verification, optimization, and finalization, the dust collector stress monitoring system of this application was practically applied to the dust collectors of Units 1 and 2. One set of dust collector stress monitoring system was installed in each unit, thus achieving physical isolation between the monitoring systems of the two units. It is divided into four main modules: stress sensing module, data transmission and acquisition, data storage and analysis, and DCS system integration and display.

[0045] Each ash hopper's measuring point is connected by two signal transmission optical cables, which transmit the signals from each sensor to the demodulator. The industrial control computer transmits the signals to the DCS system through a switching grid. To protect the cables, the optical cable at the ash hopper end is threaded into a galvanized steel pipe, while other optical cables are laid in cable trays.

[0046] Data acquisition utilizes two 16-channel fiber Bragg grating demodulators. Each demodulator integrates a light source, data acquisition, and network communication modules to demodulate the fiber Bragg grating strain sensor signals and acquire the sensor data. Data storage and analysis are handled by industrial control computers. Industrial control computer 1 connects to demodulator 1 to store and display its data; industrial control computer 2 connects to demodulator 2 to store and display its data.

[0047] Data is integrated into the DCS system, and data access is achieved through photoelectric conversion to the DCS system server. The DCS system integration of the two units was completed during the overhaul periods of Unit 2 and Unit 1 in May and October 2024. In the central control room, the structural stress and ash level of the ash hopper can be monitored in real time, and ash removal measures can be taken based on stress alarm information to ensure the safety of the ash hopper.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A monitoring and early warning system for a dust collector hopper structure, characterized in that, include: Fiber Bragg grating sensors, fiber Bragg grating demodulators, routers, converters, and industrial control computers; among them... The fiber optic grating sensor includes a fiber optic grating strain sensor and a fiber optic grating temperature sensor. The fiber optic grating strain sensor is used to collect strain information of the ash hopper in real time, and the fiber optic grating temperature sensor is used to perform temperature compensation on the fiber optic grating strain sensor. The optical signal collected by the fiber Bragg grating sensor is transmitted to the fiber Bragg grating demodulator via optical cable. The fiber Bragg grating demodulator demodulates the wavelength offset and transmits it to the industrial control computer in the ash removal control room. The industrial control computer promptly judges the stress state of the ash hopper based on real-time monitoring data and issues alarms for abnormal situations. The router is responsible for transmitting data from each fiber Bragg grating demodulator to the industrial control computer in the dust removal room, or transmitting the integrated data to the DCS system servers of different units in the central control room; the converter is responsible for the conversion of photoelectric signals during transmission.

2. The monitoring and early warning system for the dust collector hopper structure according to claim 1, characterized in that, The fiber Bragg grating sensors are installed on the dust collector hopper wall panel and stiffening ribs; eight fiber Bragg grating strain sensors are installed, with measuring points numbered #1, #2, #3, #5, #6, #7, #9 and #10; two fiber Bragg grating temperature sensors are installed, with measuring points numbered #4 and #8; all fiber Bragg grating sensors are connected in series to the fiber Bragg grating demodulator and the industrial control computer.

3. The monitoring and early warning system for the dust collector hopper structure according to claim 2, characterized in that, The fiber optic grating sensor is a spot-welded sensor, which is welded to the ash hopper using a spot welding machine; then a protective cover is installed, which is welded to the surface and the outside of the strain gauge to prevent external extrusion and deformation; and corresponding numbered labels are affixed to the ends of the sensor wires.

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