Novel intelligent detection control system for air pre-heater of coal-fired unit

Abstract

The invention provides an intelligent detection control system for an air pre-heater of a coal-fired unit, and the system comprises a monitoring module, a data processing unit, a prediction and diagnosis unit, a control instruction generation unit, and a control execution interface. The parameters include coal quality, ammonia escape amount, SO3 concentration, running states of an air pre-heater and an auxiliary system and the like. The data processing unit analyzes the parameters based on a preset model, and the prediction and diagnosis unit predicts the blockage and / or low-temperature corrosion risk of the air pre-heater and diagnoses the operation state of the air pre-heater auxiliary system. And the control instruction generation unit generates a control instruction aiming at a fire coal blending combustion system, a denitration system, a combustion system, a desulfurization system or an air pre-heater auxiliary system according to the prediction and diagnosis results, and sends the control instruction to a corresponding system for execution through the control execution interface. The application can effectively improve the operation stability of a coal-fired unit, reduce pollutant emission, prolong the service life of equipment, optimize the operation of a denitration system, and improve the operation safety and economy of the air pre-heater.

Description

Technical Field

[0001] The present application belongs to the technical field of coal-fired unit equipment monitoring and control, and specifically relates to a new type of coal-fired unit air preheater intelligent detection and control system. Background Art

[0002] With the increasing global demand for energy efficiency and environmental protection, coal-fired power generation units are facing the challenge of complex and changing operating conditions. The unit operating mode has shifted from traditional steady-state to peak-shaving and frequency regulation, and has been in a low-load and frequently variable load state for a long time. In this process, there are many problems that need to be solved urgently. For example, the coal blending process lacks accurate coal quality detection methods for the incoming coal. Coal quality fluctuations seriously affect combustion stability and efficiency, increase pollutant emissions, and have an adverse effect on equipment life. The denitrification system causes an imbalance in the ammonia-nitrogen molar ratio due to load changes. The existing ammonia slip detection technology is not accurate enough, causing deviations in denitrification operations, which in turn endangers the operation of auxiliary equipment after the furnace. As a key equipment, the air preheater lacks a comprehensive and intelligent monitoring and prediction system for its operating status, which is prone to blockage and low-temperature corrosion, seriously threatening the safe and economic operation of the unit. Summary of the Invention

[0003] The purpose of this application is to provide an intelligent detection and control system for the air preheater of a coal-fired unit, which can improve the operating stability of the coal-fired unit, reduce pollutant emissions, extend equipment life, optimize the operation of the denitrification system, and improve the safety and economy of the air preheater operation.

[0004] The present application provides an intelligent detection and control system for an air preheater of a coal-fired unit, comprising a monitoring module, which is arranged at a corresponding position of the coal-fired unit and is used to monitor in real time the parameters affecting the operating state of the air preheater, the parameters including the quality of the coal fed into the furnace, the amount of ammonia escape in the flue gas, the SO3 concentration in the flue gas, the operating state of the air preheater and at least one of the operating state of the air preheater auxiliary system; a data processing unit, which is connected to the monitoring module and is used to receive the parameters and process and analyze the parameters based on a preset model; a prediction and diagnosis unit, which is integrated in the data processing unit or is communicatively connected thereto and is used to predict the blockage and / or low-temperature corrosion risk of the air preheater based on the parameters and the processing and analysis results of the data processing unit, and to diagnose the operating state of the air preheater auxiliary system; a control instruction generation unit, which is integrated in the data processing unit or is communicatively connected thereto and is used to generate control instructions for a coal blending control system, a denitrification system, a combustion system, a desulfurization system or an air preheater auxiliary system according to the prediction and diagnosis results of the prediction and diagnosis unit; and a control execution interface, which is used to send the control instructions to the corresponding system and execute the control instructions in each system.

[0005] Furthermore, the present application also proposes that the air preheater auxiliary system includes at least one or more of an air volume splitting and anti-blocking system, a soot blower and an air heater, and the control instruction generation unit generates control instructions for adjusting the air volume distribution of the air volume splitting and anti-blocking system, the soot blowing frequency of the soot blower or the heating power of the air heater.

[0006] Furthermore, the present application also proposes that the data processing unit is used to perform at least one of the following operations: calculating the flue gas acid dew point temperature based on the coal quality of the incoming coal; calculating the flue gas acid dew point temperature based on the ammonia slip amount, ammonia injection amount and flue gas NO X The ammonia-nitrogen molar ratio is calculated based on the SO3 concentration, the ammonia escape amount and the flue gas temperature; the ammonium bisulfate generation rate index is calculated based on the SO3 concentration, the ammonia escape amount and the flue gas temperature, and the ammonium bisulfate generation rate is predicted according to the generation rate index.

[0007] Furthermore, the present application also proposes that the ammonia slip amount, ammonia injection amount and flue gas NO X The concentration calculation of the ammonia nitrogen molar ratio includes: calculating the ammonia nitrogen molar ratio according to the following (1): (1) in, is the ammonia injection flow rate, is the density of ammonia, and are the molar masses of ammonia and NOx, respectively, is the ammonia escape concentration, is the inlet NOx concentration.

[0008] Furthermore, the present application also proposes that the calculation of the ammonium bisulfate generation rate index based on the SO3 concentration, ammonia escape amount and flue gas temperature includes: calculating the generation rate index according to the following formula (2): (2) in, is the SO3 concentration, is the ammonia slip, is the flue gas temperature, and K is the correction coefficient.

[0009] Furthermore, the present application also proposes that the control instruction generation unit is used to perform at least one of the following operations: based on the comparison result of the flue gas acid dew point temperature with the preset safety threshold, generate an instruction to adjust the air volume distribution ratio of the air volume cutting and anti-blocking system, the soot blowing frequency of the soot blower or the heating power of the heater; when the ammonia nitrogen molar ratio exceeds the preset range, generate a control instruction to reduce the ammonia injection amount of the denitrification system or optimize the combustion temperature; based on the matching result of the ammonium bisulfate generation rate index and the historical data model, generate an instruction to adjust the coal blending ratio or the desulfurizer injection amount to inhibit the generation of ammonium bisulfate; when the risk of low-temperature corrosion is predicted, generate a control instruction to increase the heating power of the heater or optimize the cold end temperature of the air preheater.

[0010] Furthermore, the present application also proposes that the monitoring module includes a laser online analyzer installed above the front conveyor belt of the coal mill, which is used to collect coal samples entering the furnace in real time and analyze coal quality parameters; the data processing unit compares the coal quality parameters with the preset standard range, and generates an alarm message when the comparison result deviates from the threshold, and sends an adjustment instruction to the coal blending control system.

[0011] Furthermore, the present application also proposes that the monitoring module also includes an ammonia escape detection system configured at the outlet of the denitrification reaction device and the flue of the air preheater outlet, which is used to detect the ammonia escape concentration through laser absorption spectroscopy technology.

[0012] Furthermore, the present application also proposes that the monitoring module also includes a SO3 online analyzer installed in the vertical section or flow rate stable area of the flue gas duct.

[0013] Furthermore, the present application also proposes that the monitoring module also includes sensors installed on the rotor, heat storage element, inlet and outlet flues and other parts of the air preheater, and the sensors include but are not limited to at least one of a temperature sensor, a pressure sensor, and a flow sensor.

[0014] From the above, it can be seen that the intelligent detection and control system for the air preheater of a coal-fired unit provided in this application predicts and diagnoses the blockage and low-temperature corrosion risks of the air preheater by real-time monitoring and analysis of parameters affecting the operating status of the air preheater, and generates corresponding control instructions. It effectively solves the problems of coal quality fluctuations, denitrification system operation deviations, air preheater blockage and low-temperature corrosion during the operation of the coal-fired unit, and has the advantages of improving the operating stability of the coal-fired unit, reducing pollutant emissions, extending equipment life, optimizing the operation of the denitrification system, and improving the safety and economy of the air preheater operation. DETAILED DESCRIPTION

[0015] This application proposes an intelligent detection and control system for an air preheater in a coal-fired power plant, comprising a monitoring module, a data processing unit, a prediction and diagnosis unit, a control instruction generation unit, and a control execution interface. The monitoring module is located at a corresponding location in the coal-fired power plant and is used to monitor in real time parameters affecting the air preheater's operating status. These parameters include at least one of the following: the quality of the incoming coal, the amount of ammonia slip in the flue gas, the SO₃ concentration in the flue gas, the operating status of the air preheater, and the operating status of the air preheater's auxiliary systems. The data processing unit is connected to the monitoring module and is used to receive the parameters and process and analyze them based on a preset model. The prediction and diagnosis unit is integrated with the data processing unit or is in communication with it. Based on the parameters and the processing and analysis results of the data processing unit, it predicts the risk of air preheater blockage and / or low-temperature corrosion, and diagnoses the operating status of the air preheater's auxiliary systems. The control instruction generation unit is integrated with the data processing unit or is in communication with it. Based on the prediction and diagnosis results of the prediction and diagnosis unit, it generates control instructions for the coal blending control system, denitrification system, combustion system, desulfurization system, or air preheater auxiliary systems. The control execution interface is used to send control instructions to the corresponding system and execute the control instructions in each system.

[0016] The monitoring module preferably includes a laser online analyzer mounted above the coal mill conveyor belt to collect real-time samples of incoming coal and analyze coal quality parameters. A data processing unit compares the coal quality parameters with pre-set standard ranges. If the comparison results deviate from the threshold, an alarm is generated and an adjustment instruction is sent to the coal blending control system.

[0017] Preferably, the monitoring module may further include an ammonia escape detection system disposed at the outlet of the denitrification reaction device and the flue gas outlet of the air preheater, for detecting the ammonia escape concentration by laser absorption spectroscopy technology.

[0018] Preferably, the monitoring module may also include a SO3 online analyzer installed in the vertical section of the flue gas duct or the flow rate stable area, and sensors installed in the rotor, heat storage element, inlet and outlet flues and other parts of the air preheater. These sensors include but are not limited to at least one of a temperature sensor, a pressure sensor, and a flow sensor.

[0019] The technical solution of this application, through real-time monitoring and analysis of the operating status of the air preheater of a coal-fired unit, can effectively predict and diagnose the risks of air preheater blockage and low-temperature corrosion, and generate corresponding control instructions, thereby achieving precise control of the coal blending control system, denitrification system, combustion system, desulfurization system, or air preheater auxiliary systems. Compared with existing technologies, this application can improve the stability and safety of air preheater operation, reduce equipment failures and downtime, and improve the overall operating efficiency of coal-fired units.

[0020] Furthermore, the present application also proposes that the air preheater auxiliary system includes at least one or more of an air volume cutting and anti-blocking system, a soot blower and an air heater, and the control instruction generation unit generates control instructions for adjusting the air volume distribution of the air volume cutting and anti-blocking system, the soot blowing frequency of the soot blower or the heating power of the air heater.

[0021] Specifically, the air volume splitting and anti-blocking system effectively prevents dust accumulation within the air preheater by adjusting the air volume distribution ratio, thereby reducing the risk of blockage. The sootblower's sootblowing frequency can be optimized based on the amount of soot accumulated within the air preheater, avoiding excessive or insufficient sootblowing. The heater's heating power adjustment adjusts the heating power in real time based on changes in the air preheater's cold-end temperature, thereby preventing low-temperature corrosion.

[0022] As a preferred embodiment, air volume distribution in the air volume splitting and anti-blocking system can be achieved by adjusting the damper opening or fan speed. The sootblower's blowing frequency can be controlled by controlling the solenoid valve's switching frequency or adjusting the compressed air supply. The heater's heating power can be adjusted by adjusting the power output of the electric heater or adjusting the steam flow rate.

[0023] Therefore, by adjusting the operating parameters of the air preheater auxiliary system, the present application can effectively prevent air preheater blockage and low-temperature corrosion problems. Compared with the existing technology, the technical solution of the present application can dynamically adjust the operating parameters of the auxiliary system according to the real-time operating status of the air preheater, thereby improving the operating efficiency and safety of the air preheater.

[0024] Furthermore, the present application also proposes that the data processing unit is used to perform at least one of the following operations: calculate the flue gas acid dew point temperature based on the coal quality of the coal fed into the furnace; calculate the flue gas acid dew point temperature based on the ammonia escape amount, the ammonia injection amount and the flue gas NO X The ammonia-nitrogen molar ratio is calculated based on the SO3 concentration; the ammonium bisulfate generation rate index is calculated based on the SO3 concentration, ammonia escape amount and flue gas temperature, and the ammonium bisulfate generation rate is predicted based on the generation rate index.

[0025] The flue gas acid dew point temperature is calculated based on the quality of the incoming coal. A coal quality analyzer can be used to obtain parameters such as sulfur, ash, and volatile matter. Combined with flue gas composition data, the acid dew point temperature calculation formula can be used for calculation. Specifically, the acid dew point temperature calculation formula can be derived based on factors such as the sulfur content of the coal, the water vapor content of the flue gas, and the flue gas temperature, thereby obtaining the flue gas acid dew point temperature. As a preferred embodiment, the calculation can be performed using empirical formulas or numerical simulation methods to ensure the accuracy of the results.

[0026] Furthermore, based on the ammonia slip, ammonia injection amount and flue gas NO X The concentration calculation of ammonia nitrogen molar ratio can be performed using the following formula: (1) in, is the ammonia injection flow rate, is the density of ammonia, and are the molar masses of ammonia and NOx, respectively, is the ammonia escape concentration, is the inlet NOx concentration. The ammonia injection flow rate can be monitored in real time using a flow meter, the ammonia density can be corrected using temperature and pressure parameters, the molar masses of ammonia and NOx can be obtained from a chemical handbook, and the ammonia slip concentration and inlet NOx concentration can be measured using a flue gas analyzer. This allows for accurate calculation of the ammonia-nitrogen molar ratio, providing a basis for optimizing the denitrification system.

[0027] In addition, the ammonium bisulfate generation rate index can be calculated based on SO3 concentration, ammonia escape amount and flue gas temperature by the following formula: (2) SO3 concentration can be monitored in real time using an online SO3 analyzer, ammonia escape can be detected using an ammonia escape detection system, and flue gas temperature can be measured using a temperature sensor. By calculating the generation rate index, the ammonium bisulfate generation rate can be predicted, providing a basis for adjusting the coal blending ratio and desulfurizer injection rate.

[0028] The technical solution of this application uses a data processing unit to process the coal quality, ammonia escape, ammonia injection amount, flue gas NO X Real-time calculation and analysis of parameters such as CO2 concentration, SO3 concentration, and flue gas temperature can accurately predict flue gas acid dew point temperature, ammonia-nitrogen molar ratio, and ammonium bisulfate generation rate. This allows for timely identification and resolution of issues such as acid dew point corrosion, ammonia-nitrogen molar ratio imbalance, and ammonium bisulfate generation that may arise during coal-fired unit operation, effectively improving unit operational stability and safety. Compared to existing technologies, this solution, through comprehensive analysis of multiple parameters, more accurately predicts and controls unit operating conditions, avoiding equipment damage and reduced efficiency caused by parameter fluctuations. Furthermore, the present application also proposes that the control instruction generation unit is used to perform at least one of the following operations: based on the comparison result of the flue gas acid dew point temperature with the preset safety threshold, generate an instruction to adjust the air volume distribution ratio of the air volume cutting and anti-blocking ash system, the soot blowing frequency of the soot blower or the heating power of the heater; when the ammonia nitrogen molar ratio exceeds the preset range, generate a control instruction to reduce the ammonia injection amount of the denitrification system or optimize the combustion temperature; based on the matching result of the ammonium bisulfate generation rate index and the historical data model, generate an instruction to adjust the coal blending ratio or the desulfurizer injection amount to inhibit the generation of ammonium bisulfate; when the risk of low-temperature corrosion is predicted, generate a control instruction to increase the heating power of the heater or optimize the cold end temperature of the air preheater.

[0029] Specifically, the air volume distribution ratio of the air volume splitting and anti-blocking ash system can be adjusted by changing the fan speed or adjusting the opening of the air damper. The soot blowing frequency of the soot blower can be controlled by adjusting the start-up interval time of the soot blower. The heating power of the heater can be achieved by adjusting the current or voltage of the heating element. Reducing the amount of ammonia sprayed in the denitrification system can be achieved by reducing the flow of the ammonia injection pump or closing some ammonia injection nozzles. Optimizing the combustion temperature can be achieved by adjusting the air-fuel ratio of the burner or changing the position of the burner. Adjusting the coal blending ratio can be achieved by changing the delivery ratio of different types of coal. The desulfurizer injection amount can be adjusted by changing the flow of the injection pump or increasing the number of injection nozzles. Increasing the heating power of the heater can be achieved by increasing the number of heating elements or increasing the power of the heating elements. Optimizing the cold end temperature of the air preheater can be achieved by adjusting the flow of the cooling medium or changing the temperature of the cooling medium.

[0030] Therefore, the technical solution of the present application generates corresponding control instructions by real-time monitoring and analysis of the operating parameters of the coal-fired unit to optimize the operating status of the system. Among them, the monitoring and adjustment of the flue gas acid dew point temperature can effectively prevent low-temperature corrosion of the air preheater; the monitoring and adjustment of the ammonia nitrogen molar ratio can optimize the operating efficiency of the denitrification system and reduce ammonia escape; the monitoring and adjustment of the ammonium bisulfate generation rate can inhibit the generation of ammonium bisulfate and prevent the blockage of the air preheater; the prediction and adjustment of the low-temperature corrosion risk can improve the operating safety of the air preheater. Compared with the existing technology, the technical solution of the present application can more comprehensively monitor and predict the operating status of the air preheater, and by generating corresponding control instructions, it can achieve optimized control of each system of the coal-fired unit, thereby improving the operating efficiency and safety of the system.

[0031] Furthermore, the present application also proposes that the monitoring module includes a laser online analyzer installed above the conveyor belt in front of the coal mill, which is used to collect coal samples entering the furnace in real time and analyze coal quality parameters; the data processing unit compares the coal quality parameters with the preset standard range, and generates an alarm message when the comparison result deviates from the threshold, and sends an adjustment instruction to the coal blending control system.

[0032] The laser online analyzer uses non-contact laser technology to perform real-time analysis of incoming coal samples, rapidly acquiring coal quality parameters such as ash, volatile matter, and fixed carbon. The data processing unit compares these coal quality parameters against a preset standard range. If any parameters deviate from the threshold, an alarm is generated and an adjustment instruction is sent to the coal blending control system to ensure stable coal quality and avoid reduced combustion efficiency and increased pollutant emissions due to fluctuations in coal quality.

[0033] Specifically, the laser online analyzer is installed above the coal mill conveyor belt, ensuring coal quality analysis before it enters the mill, providing timely data support for subsequent combustion control. By comparing coal quality parameters with preset standard ranges in real time, the data processing unit can quickly identify coal quality anomalies and generate corresponding adjustment instructions, such as adjusting the coal blend ratio or optimizing the combustion temperature, to maintain stable operation of the combustion system.

[0034] Furthermore, the present application also proposes that the monitoring module also includes an ammonia escape detection system configured at the outlet of the denitrification reaction device and the flue gas outlet of the air preheater, which is used to detect the ammonia escape concentration through laser absorption spectroscopy technology. The ammonia escape detection system is a detection device based on laser absorption spectroscopy technology. Its working principle is to pass a laser beam of a specific wavelength through the flue gas and measure the degree of absorption of the laser by ammonia molecules, so as to accurately calculate the ammonia escape concentration. The core components of the system include a laser transmitter, a receiver, a signal processor and a data transmission module. The laser transmitter emits a laser beam of a specific wavelength, the receiver detects the change in laser intensity after passing through the flue gas, the signal processor converts the received optical signal into an electrical signal and performs data analysis, and finally transmits the ammonia escape concentration data to the data processing unit in real time through the data transmission module.

[0035] As a preferred embodiment, the ammonia escape detection system can be installed at specific locations at the outlet of the denitrification reactor and at the flue gas outlet of the air preheater to ensure the accuracy and representativeness of the test data. The detection point at the outlet of the denitrification reactor is used to monitor the real-time status of ammonia escape during the operation of the denitrification system, while the detection point at the flue gas outlet of the air preheater is used to assess the impact of ammonia escape on the air preheater's operating status. This dual-point detection allows for a more comprehensive understanding of the dynamic changes in ammonia escape, providing reliable data support for the subsequent generation of control instructions.

[0036] Specifically, ammonia escape detection systems can be implemented in two ways: one uses single-wavelength laser absorption spectroscopy, detecting ammonia concentration using a single-wavelength laser beam; the other uses multi-wavelength laser absorption spectroscopy, using multiple-wavelength laser beams to simultaneously detect multiple gas components, including ammonia and sulfur dioxide. The use of multi-wavelength technology can further improve the comprehensiveness and accuracy of detection, but it also increases system complexity and cost.

[0037] Therefore, the technical solution of the present application solves the problem of insufficient accuracy of ammonia escape detection in the prior art by introducing an ammonia escape detection system. The high-precision detection capability of the ammonia escape detection system can monitor the ammonia escape concentration in real time, provide data support for the optimized operation of the denitrification system, and thus avoid abnormal operation of the post-furnace auxiliary equipment due to excessive ammonia escape. In addition, the real-time data transmission function of the system can also be seamlessly connected with the data processing unit to further enhance the intelligence level of the system. Compared with the prior art, the technical solution of the present application has the advantages of high detection accuracy, fast response speed, and strong real-time data, and can effectively improve the overall performance of the intelligent detection and control system of the air preheater of the coal-fired unit.

[0038] Furthermore, the present application proposes that the monitoring module also includes an online SO3 analyzer installed in a vertical section of the flue gas duct or in an area with stable flow. This online SO3 analyzer is used to detect the SO3 concentration in the flue gas in real time, ensuring the accuracy and stability of the detection data. Specifically, by installing the online SO3 analyzer in a vertical section of the flue gas duct or in an area with stable flow, it can effectively avoid the impact of uneven flue gas flow on the detection results, thereby improving detection accuracy. As a preferred embodiment, the online SO3 analyzer can use laser absorption spectroscopy or electrochemical sensor technology to achieve rapid and continuous monitoring of SO3 concentration.

[0039] This application addresses the existing issue of inaccurate SO3 concentration detection due to uneven flue gas flow by installing an online SO3 analyzer in a vertical section of the flue gas duct or in an area with stable flow. This allows for more accurate SO3 concentration data, providing a reliable basis for subsequent flue gas treatment and control. Compared to existing technologies, this application's technical solution offers significant advantages in detection accuracy and stability, effectively improving the overall performance of the intelligent detection and control system for coal-fired unit air preheaters.

[0040] Furthermore, the present application also proposes that the monitoring module also includes sensors installed in the rotor, heat storage element, inlet and outlet flues and other parts of the air preheater, and the sensors include but are not limited to at least one of a temperature sensor, a pressure sensor, and a flow sensor.

[0041] Specifically, temperature sensors monitor temperature changes in various parts of the air preheater in real time, ensuring that temperatures remain within a reasonable range during operation and preventing equipment damage or efficiency loss due to excessively high or low temperatures. Pressure sensors detect pressure changes within the air preheater to ensure system pressure stability and prevent equipment failure or safety hazards caused by abnormal pressure. Flow sensors monitor the flow of gas or liquid within the air preheater, ensuring that flow rates remain within a reasonable range and preventing system instability or efficiency loss caused by abnormal flow rates.

[0042] As a preferred embodiment, the temperature sensor can be a thermocouple or a thermistor. Thermocouples are suitable for high-temperature environments and can quickly respond to temperature changes, while thermistors are suitable for medium and low-temperature environments and have higher measurement accuracy. The pressure sensor can be a piezoresistive or capacitive sensor. Piezoresistive sensors have higher sensitivity and stability, while capacitive sensors are suitable for high-pressure environments and have better anti-interference capabilities. The flow sensor can be a turbine flowmeter or an ultrasonic flowmeter. Turbine flowmeters are suitable for measuring the flow of gases and liquids and have higher accuracy and response speed. Ultrasonic flowmeters are suitable for measuring the flow of large pipes and complex fluids and have the advantage of non-contact measurement.

[0043] In this regard, the technical solution of this application, through the integrated application of multiple sensors, can comprehensively and in real time monitor the operating status of the air preheater, promptly identify and address potential problems, and ensure the safe and stable operation of the air preheater. Compared with existing technologies, the technical solution of this application has higher monitoring accuracy and a more comprehensive monitoring range, which can effectively prevent the occurrence of problems such as air preheater blockage and low-temperature corrosion, and improve the operating efficiency and safety of the unit.

[0044] The above content is merely an example and explanation of the concept of the present invention. Technicians in this technical field may make various modifications or additions to the specific embodiments described, or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

[0045] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative use of these terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0046] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An intelligent detection and control system for air preheater of coal-fired unit, characterized in that: include: A monitoring module is configured at a corresponding position of the coal-fired unit and is used to monitor in real time parameters affecting the operating status of the air preheater, the parameters including at least one of the quality of the incoming coal, the amount of ammonia escape in the flue gas, the SO3 concentration in the flue gas, the operating status of the air preheater, and the operating status of the air preheater auxiliary system; a data processing unit, connected to the monitoring module, configured to receive the parameters and process and analyze the parameters based on a preset model; a prediction and diagnosis unit, integrated in or in communication with the data processing unit, for predicting the blockage and / or low-temperature corrosion risk of the air preheater based on the parameters and the processing and analysis results of the data processing unit, and diagnosing the operating status of the air preheater auxiliary system; a control instruction generating unit, integrated into the data processing unit or in communication therewith, for generating control instructions for the coal blending control system, the denitrification system, the combustion system, the desulfurization system or the air preheater auxiliary system based on the prediction and diagnosis results of the prediction and diagnosis unit; The control execution interface is used to send the control instruction to the corresponding system and execute the control instruction in each system.

2. The system according to claim 1, wherein The air preheater auxiliary system includes at least one or more of an air volume splitting and anti-blocking dust system, a soot blower and an air heater.

3. The system according to claim 2, wherein: The data processing unit is configured to perform at least one of the following operations: Calculating the flue gas acid dew point temperature based on the coal quality of the incoming coal; Based on the ammonia slip amount, ammonia injection amount and flue gas NO X The concentration was used to calculate the ammonia nitrogen molar ratio; An ammonium bisulfate generation rate index is calculated based on the SO3 concentration, ammonia escape amount and flue gas temperature, and the ammonium bisulfate generation rate is predicted according to the generation rate index.

4. The system according to claim 3, wherein: The method is based on the ammonia slip amount, ammonia injection amount and flue gas NO X Concentration calculation of ammonia nitrogen molar ratio, including: The ammonia nitrogen molar ratio was calculated according to the following formula (1): （1） in, is the ammonia injection flow rate, is the density of ammonia, and are the molar masses of ammonia and NOx, respectively, is the ammonia escape concentration, is the inlet NOx concentration.

5. The system according to claim 3, wherein: The calculation of the ammonium bisulfate generation rate index based on the SO3 concentration, ammonia escape amount and flue gas temperature includes: The rate index is calculated according to the following formula (2): （2） in, is the SO3 concentration, is the ammonia slip, is the flue gas temperature, and K is the correction coefficient.

6. The system according to any one of claims 3 to 5, characterized in that The control instruction generating unit is configured to perform at least one of the following operations: According to the comparison result of the flue gas acid dew point temperature and the preset safety threshold, an instruction is generated to adjust the air volume distribution ratio of the air volume splitting and anti-blocking system, the soot blowing frequency of the soot blower, or the heating power of the heater; When the ammonia-nitrogen molar ratio exceeds a preset range, generating a control instruction to reduce the ammonia injection amount of the denitration system or optimize the combustion temperature; Based on the matching result of the ammonium bisulfate generation rate index and the historical data model, generating an instruction to adjust the coal blending ratio or the desulfurization agent injection amount to suppress the generation of ammonium bisulfate; When the risk of low-temperature corrosion is predicted, a control instruction is generated to increase the heating power of the heater or optimize the cold end temperature of the air preheater.

7. The system according to claim 1, wherein: The monitoring module includes a laser online analyzer installed above the conveyor belt in front of the coal mill, which is used to collect coal samples entering the furnace in real time and analyze coal quality parameters; the data processing unit compares the coal quality parameters with the preset standard range, and generates an alarm message if the comparison result deviates from the threshold, and sends an adjustment instruction to the coal blending control system.

8. The system according to claim 1, wherein: The monitoring module also includes an ammonia escape detection system configured at the outlet of the denitrification reaction device and the flue gas outlet of the air preheater, which is used to detect the ammonia escape concentration through laser absorption spectroscopy technology.

9. The system according to claim 1, wherein: The monitoring module further comprises a SO3 online analyzer installed in a vertical section or a flow rate stable area of the flue gas duct.

10. The system according to claim 1, wherein: The monitoring module also includes sensors installed on the rotor, heat storage element, inlet and outlet flues and other parts of the air preheater, and the sensors include but are not limited to at least one of a temperature sensor, a pressure sensor and a flow sensor.

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