An adaptive precise soot blowing system of rotary preheater

Abstract

The application discloses a kind of self-adapting precision soot blower system of rotary preheater, including preheater being equipped with shell and rotor, each soot blower;Shell is equipped with several groups of infrared thermal imaging sensor device and ultrasonic sensor device, each group of infrared thermal imaging sensor device is equipped with several infrared thermal imaging sensor probes by upper fixed pipe and lower fixed pipe, several sleeve tubes, protection shell;Each group of ultrasonic sensor includes several hot-end waveguide rods and cold-end waveguide rods passing through shell, hot-end waveguide rod is connected with respective ultrasonic emission / reflection module, and cold-end waveguide rod is connected with respective ultrasonic receiving module;Each infrared thermal imaging sensor probe, ultrasonic emission / reflection module, ultrasonic receiving module are connected with data processing module, and data processing module is connected with DCS or PLC system and control module respectively;The application can accurately locate block point and judge its block degree, so as to control soot blower to blow specifically, and has strong self-adapting ability, can reduce invalid soot blowing times, reduce energy consumption and preheater element abrasion, prolong element service life.

Description

Technical Field

[0001] This invention relates to a soot blowing system for a rotary preheater, and more particularly to an adaptive precision soot blowing system for a rotary preheater. Background Technology

[0002] Ammonium bisulfate clogging is currently the most significant problem in power plant boiler air preheaters. Current anti-clogging technologies primarily optimize aspects such as heat exchange element plate design, cold-end overall temperature, and reducing ammonia escape. In actual operation, the formation of ammonium bisulfate is unavoidable. If not removed promptly, the accumulated ammonium bisulfate will absorb ash and clog element channels. Therefore, the effectiveness of the sootblower is the most crucial element in anti-clogging measures.

[0003] Traditional soot blowing methods are generally step-by-step or step-back soot blowing, which uses fixed logic and can only blow at fixed times and across the entire range. They cannot dynamically adjust the soot blowing strategy according to the ash accumulation status, resulting in low soot blowing efficiency. Furthermore, due to the non-uniformity of flue gas and flow field, the clogging situation varies in each area. To ensure the soot blowing effect in all areas, the soot blowing frequency must be increased, which will accelerate the damage of components in normal areas and increase energy consumption. On the other hand, if the soot blowing frequency is too low, the accumulated ash cannot be cleaned in time. After a long period of accumulation, the ash will harden and become difficult to remove, leading to serious blockage.

[0004] Because traditional soot blowing methods have many problems, various intelligent soot blowing methods have emerged, the most common of which are as follows: (1) The pressure difference measurement method is used to locate the blockage area, thereby optimizing the soot blowing strategy. However, the pressure difference is a range measurement, which can only measure the average value within the area. Therefore, it can only locate the blockage within a certain range and cannot pinpoint the exact blockage point. (2) Temperature measurement method. The heat exchange efficiency is calculated based on temperature changes. A significant decrease in heat exchange efficiency indicates severe blockage. Due to the dynamic nature of flue gas, this method can only reflect the blockage situation within a relatively large area near the measurement point and cannot accurately pinpoint the location of the blockage. (3) Theoretically, image detection and visualization techniques can locate the blockage point, but only the surface of the component can be seen, and the blockage in the middle part of the component cannot be analyzed. Furthermore, the reliability is greatly affected by the resolution and flue gas ash content.

[0005] (4) Based on operating parameters, such as load, flue gas temperature, dust content, etc., the principle of this method is to infer the blockage trend through the above parameters and adjust the soot blowing method accordingly. It can only play a predictive role and still cannot accurately locate the blockage point. While these technologies have abandoned the fixed logic of blowing away ash, they are still relatively crude because they cannot accurately locate the blockage point. They cannot fundamentally solve the problem of accurately blowing away the blockage point and have certain limitations. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned shortcomings of the prior art by providing an adaptive precision soot blowing system for a rotary preheater. This system can accurately locate blockage points and determine the degree of blockage, thereby controlling the soot blower to blow in a targeted manner. It also has strong adaptive capabilities, which can reduce the number of ineffective soot blowing operations, reduce energy consumption and wear on preheater components, and extend the service life of the components.

[0007] To achieve the above objectives, the adaptive precision soot blowing system for the rotary preheater of the present invention includes a preheater with a shell and a rotor, and soot blowers located on the upper and lower sides of the rotor, each soot blower being connected to a control module; characterized in that: the shell is equipped with one or more sets of infrared thermal imaging sensors and ultrasonic sensors, each set of infrared thermal imaging sensors including an upper fixed tube and a lower fixed tube located radially to the rotor, the upper and lower fixed tubes being fixedly connected to the shell and located on the upper and lower sides of the rotor, the upper and lower fixed tubes being connected to several longitudinal sleeves, each sleeve being equipped with a protective shell, the front end of the protective shell being fixedly provided with a glass window, the protective shell... Each component is equipped with an infrared thermal imaging sensor probe. Each group of ultrasonic sensors includes several hot-end waveguide rods and cold-end waveguide rods arranged radially along the rotor and passing through the outer shell. The hot-end and cold-end waveguide rods are arranged in longitudinal pairs. Each hot-end and cold-end waveguide rod is equipped with a wind-cooling sleeve fixed to the shell. Each hot-end waveguide rod is connected to its respective ultrasonic transmitting / reflecting module, and each cold-end waveguide rod is connected to its respective ultrasonic receiving module. Each infrared thermal imaging sensor probe, ultrasonic transmitting / reflecting module, and ultrasonic receiving module is connected to a data processing module. The data processing module is connected to a DCS or PLC system and the control module, respectively.

[0008] This invention utilizes radially arranged sets of infrared thermal imaging sensors and ultrasonic sensors to detect the entire rotor along its radius. Each infrared thermal imaging sensor probe determines the temperature distribution of the rotor's hot and cold end components. Blocked areas, due to poor heat exchange, have locally low temperatures and are displayed as cold zones within the temperature field, while normal areas have high component metal wall temperatures and are displayed as hot zones, thus achieving precise location of the blockage point. Simultaneously, each set of hot-end and cold-end waveguide rods emits ultrasonic waves point-to-point. The signal attenuation and reflectivity of the ultrasonic waves after passing through the component channels are used to accurately determine the blockage situation. The temperature and ultrasonic signals are transmitted to a DCS or PLC system via a data processing module, which automatically and accurately determines the precise location and degree of blockage. The control module then instructs the control module to control the actions of each sootblower, such as performing step / reverse blowing, fixed-point blowing, and increasing blowing pressure, to perform targeted blowing, achieving adaptive and precise sootblowing. This reduces ineffective sootblowing, lowers energy consumption and preheater component wear, and extends component lifespan.

[0009] As a further improvement of the present invention, each air-cooled sleeve is provided with a nozzle at its inner end and middle, and each nozzle is connected to a compressed air tank, and each compressed air tank is provided with an air inlet pipe; each sleeve is provided with a nozzle at its inner end and outer end, and each nozzle is connected to an air box, and each air box is provided with an air inlet pipe; compressed air is introduced into each compressed air tank and air box through the air inlet pipe, and the compressed air forms an air curtain seal and cools each air-cooled sleeve and its inner end, which can prevent the backflow of high-temperature flue gas and heat conduction, and ensure the long-term normal operation of each sensor; As a further improvement of the present invention, several sealing seats are fixed on the outer side of the outer shell and fitted around the respective waveguide rods. Each sealing seat is provided with sealing filler, and the sealing seat inside the sealing filler is connected to a sealing air pipe. The filler can form a primary seal, and compressed air is introduced through the sealing air pipe to form a sealing air chamber. The composite sealing structure can prevent flue gas leakage and ensure the sealing performance of the preheater. As a further improvement of the present invention, both the compressed air tank and the air box are located outside the outer casing, which facilitates the installation and operation of the system. In summary, this invention can accurately locate blockage points and determine the degree of blockage, thereby controlling the soot blower to blow in a targeted manner. It also has strong adaptability, which can reduce the number of ineffective soot blowing, reduce energy consumption and wear on preheater components, and extend the service life of components. Attached Figure Description

[0010] Figure 1 This is a simplified structural diagram of an embodiment of the present invention.

[0011] Figure 2 for Figure 1 Top view.

[0012] Figure 3 for Figure 1 Enlarged view of a partial structure of the Zhongyi infrared thermal imaging sensor.

[0013] Figure 4 for Figure 1 Enlarged view of a pair of hot-end and cold-end waveguide rods of an ultrasonic sensor. Detailed Implementation

[0014] The invention will be further described below with reference to the accompanying drawings.

[0015] like Figures 1 to 4As shown, the adaptive precision soot blowing system of the rotary preheater in this embodiment includes a preheater with a shell 1 and a rotor 2, and two soot blowers 3 and 4 located on the upper and lower sides of the rotor. Both soot blowers 3 and 4 are connected to the control module 28. The shell 1 is equipped with four sets of infrared thermal imaging sensors 5 and four sets of ultrasonic sensors 6. Each set of infrared thermal imaging sensors 5 includes an upper fixed tube 7 and a lower fixed tube 8 located radially on the rotor. The upper fixed tube 7 and the lower fixed tube 8 are fixedly connected to the shell 1 and located on the upper and lower sides of the rotor 2. Each of the 8 is connected to several longitudinal sleeves 10 by a fixing rod 9. Each sleeve 10 is provided with a protective shell 11 by a support frame 29. A glass window 12 is fixed at the front end of the protective shell 11. An infrared thermal imaging sensor 13 is provided inside the protective shell 11 outside the glass window 12. Several nozzles 14 are provided at the inner and outer ends of each sleeve 10. Each nozzle 14 corresponding to the same upper fixing pipe 7 and lower fixing pipe 8 is connected to its respective air box 15 through a connecting pipe. The connecting pipe can be placed inside the upper fixing pipe 7 or the fixing pipe 8. Each air box 15 is provided with an air inlet pipe. Each ultrasonic sensor group 6 includes several hot-end waveguide rods 16 and cold-end waveguide rods 17 arranged radially along the rotor and passing through the housing 1. The hot-end waveguide rods 16 and cold-end waveguide rods 17 are arranged in longitudinal pairs. Each hot-end waveguide rod 16 and cold-end waveguide rod 17 is provided with a cooling sleeve 18 fixed to the housing 1. The cooling sleeves 18 are all located inside the housing 1. Several nozzles 19 are provided at the inner end and middle of each cooling sleeve 18. Each nozzle 19 is connected to a compressed air tank 20 via a pipeline. Each compressed air tank 20 is provided with an air inlet pipe. Several sealing seats 21 are fixed to the outside of the housing 1, fitted around each waveguide rod 16 or 17. Each sealing seat 21 is equipped with a sealing filler 22, and each sealing seat 21 inside the sealing filler 22 is connected to a sealing air pipe 23; each hot-end waveguide rod 16 is connected to its respective ultrasonic transmitting / reflecting module 24, and each cold-end waveguide rod 17 is connected to its respective ultrasonic receiving module 25; each infrared thermal imaging sensor probe 13, ultrasonic transmitting / reflecting module 24, and ultrasonic receiving module 25 is connected to a data processing module 26, which is connected to the DCS system 27 and the control module 28 respectively; the ultrasonic transmitting / reflecting module 24, ultrasonic receiving module 25, compressed air tank 20, and air box 15 are all located outside the outer shell 1.

[0016] This invention utilizes radially arranged sets of infrared thermal imaging sensors 5 and ultrasonic sensors 6 to detect the entire rotor 2 along its radius. Each infrared thermal imaging sensor probe 13 is positioned above the hot-end element and below the cold-end element of the rotor 2, respectively, to collect real-time temperature field distribution data of the heated surface. The data processing module 26 generates a temperature field and divides it into a temperature field grid using an algorithm, numbering and displaying the status of different grid areas. For example, a blocked area, due to poor heat exchange, has a locally low temperature and is displayed as a cold area within the temperature field, while a normal area has a high element metal wall temperature and is displayed as a hot area. This allows for the determination of the temperature distribution of the rotor's cold and hot end elements, achieving precise location of the blockage point. Simultaneously, the inner ends of the hot-end waveguide rods 16 and cold-end waveguide rods 17 extend into the preheater and emit ultrasonic waves point-to-point along the same longitudinal straight line. The signal attenuation and reflectivity of the ultrasonic waves after passing through the element channel are used to accurately determine the blockage situation. (Ultrasonic emission / reflection module 24) High-frequency ultrasonic waves are emitted and received via the hot-end waveguide rod 16. The dust accumulation and blockage are calculated based on the echo intensity and time difference. When the component is not blocked, its reflectivity is low, and the signal attenuation rate received by the lower ultrasonic receiving module 25 is low. When the component is blocked, the signal attenuation through the component channel increases, and the reflectivity also increases. When the component is completely blocked, there is no signal at the lower receiving end, resulting in total reflection. Therefore, the attenuation rate and reflectivity of the ultrasonic signal are output to the data processing module 26 through the ultrasonic receiving module 25 and the ultrasonic transmitting / reflecting module 24, which can be used to calculate and judge the degree of blockage. This system adopts an "infrared-ultrasonic" fusion sensing method, which avoids the inability of single infrared detection to detect the degree of blockage and thus cannot qualitatively determine the degree of blockage. It also solves the problem that ultrasonic detection can only detect the degree of blockage in a localized area and cannot visualize the entire area, thus achieving accurate location of the blockage point and judgment of its degree of blockage. After the temperature and ultrasonic signals are transmitted to the DCS system 27 via the data processing module 26, the system can automatically and accurately locate the blockage point and determine the degree of blockage. Based on the degree of blockage, it is divided into light blockage, moderate blockage, and severe blockage areas. Different soot blowing trigger thresholds and soot blowing strategies are set. The operation of each soot blower 3 and 4 is controlled by the command control module 28. For example, for light blockage areas, conventional stepping / stepping back purging is performed; for moderate blockage areas, fixed-point purging is performed and the purging time is increased until the decision system determines that the degree of blockage has decreased below the trigger threshold, at which point fixed-point purging stops and stepping / stepping back action continues; for severe blockage areas, fixed-point purging is performed and the purging time is increased, while the soot blowing pressure is temporarily increased until the decision system determines that the degree of blockage has decreased below the trigger threshold, at which point fixed-point purging stops and stepping / stepping back action continues. This can form adaptive decision-making throughout the process, perform targeted purging, achieve the goal of adaptive and precise soot blowing, reduce the number of ineffective soot blowing, reduce energy consumption and wear of preheater components, and extend the service life of components. Compressed air is introduced into the compressed air tank 20 and air box 15 through the air inlet pipe. The compressed air forms an air curtain seal at the inner end of each air-cooled sleeve 18 and each sleeve 10 through each nozzle 14 and each nozzle 19, and is blown out and cooled inside the two. This can prevent the backflow of high temperature flue gas and heat conduction, and ensure the long-term normal operation of each sensor. The sealing packing 22 can form a primary seal in the sealing seat 21, and compressed air is introduced through the sealing air pipe 23 to form a sealing air chamber. The composite sealing structure can prevent flue gas leakage and ensure the sealing performance of the preheater. The DCS system can also be replaced by the PLC system, which can achieve the same function; the multi-sensor fusion technology is not limited to infrared + ultrasonic, any two or more sensor fusion technologies (including but not limited to differential pressure, temperature, visualization, mechanical waves, electromagnetic waves, radiation, etc.) can be used.

[0017] The above embodiments have been used to illustrate the invention, but it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit the invention to the scope of the described embodiments.

Claims

1. An adaptive precision soot blowing system for a rotary preheater, comprising a preheater with a shell and a rotor, and soot blowers disposed on the upper and lower sides of the rotor, each soot blower being connected to a control module; characterized in that: The housing contains one or more sets of infrared thermal imaging sensors and ultrasonic sensors. Each set of infrared thermal imaging sensors includes an upper fixed tube and a lower fixed tube located radially to the rotor. Both the upper and lower fixed tubes are fixedly connected to the housing and located on the upper and lower sides of the rotor, respectively. Several longitudinal sleeves are connected to both the upper and lower fixed tubes, and each sleeve contains a protective shell. A glass window is fixed to the front end of each protective shell, and an infrared thermal imaging sensor probe is located inside each protective shell. Each set of ultrasonic sensors includes several thermal sensors arranged radially to the rotor and passing through the housing. The system includes end waveguides and cold end waveguides, with several hot and cold end waveguides arranged longitudinally in pairs. Each hot and cold end waveguide is equipped with a cooling sleeve fixed to the housing. Each hot end waveguide is connected to its respective ultrasonic transmitting / reflecting module, and each cold end waveguide is connected to its respective ultrasonic receiving module. Each infrared thermal imaging sensor, ultrasonic transmitting / reflecting module, and ultrasonic receiving module is connected to a data processing module, which is connected to a DCS or PLC system and the control module.

2. The adaptive precision soot blowing system for a rotary preheater as described in claim 1, characterized in that: Each air-cooled sleeve has a nozzle at its inner end and middle, and each nozzle is connected to a compressed air tank. Each compressed air tank has an air inlet pipe. Each sleeve has a nozzle at its inner end and outer end, and each nozzle is connected to an air box. Each air box has an air inlet pipe.

3. An adaptive precision soot blowing system for a rotary preheater as described in claim 1 or 2, characterized in that: Several sealing seats are fixed on the outer side of the outer shell and fitted around the respective waveguide rods. Each sealing seat is provided with sealing filler, and the sealing seat inside the sealing filler is provided with a sealing air pipe.

4. The adaptive precision soot blowing system for a rotary preheater as described in claim 3, characterized in that: The compressed air tank and air box are both located outside the outer casing.

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