A control system and method for improving the low-load pulverizing and drying output of a coal-fired boiler

Abstract

The present invention provides a control system and method for improving the low-load pulverizing and drying output of a coal-fired boiler. First, the coal storage information is obtained through a sensor, and the detection area is divided for ash and moisture detection. Then the detection data is input into a fuzzy control model to obtain the optimized control parameters of the coal grinding and drying system. At the same time, the system collects the best parameters under different coal qualities, builds a coal quality database, and analyzes the data association. After receiving the expected dryness value set by the user, the system matches it with the coal quality data to obtain the corresponding control parameters. The corresponding control parameters are executed in the control system, and the dryness of the coal after pulverizing is detected in real time. If it does not meet expectations, the control parameters are optimized. It aims to improve the efficiency and quality of coal processing. It solves the problem that changes in coal quality, such as different contents of moisture, ash, volatile matter, etc., will directly affect the efficiency of coal grinding and drying.

Description

Technical Field

[0001] The invention relates to the technical field of energy conservation and emission reduction of coal-fired boilers, and in particular to a control system and method for improving the low-load pulverizing and drying output of a coal-fired boiler. Background Art

[0002] Coal-fired boiler low load refers to the state where the operating power of the boiler equipment in a coal-fired thermal power plant is lower than its full power. Generally, low load means that the boiler operates within the range of 30% to 50% of its full power. Under low load conditions, the operating efficiency and stability of the boiler will face greater challenges.

[0003] Pulverizing and drying output refers to the process by which the pulverizing system in a coal-fired boiler grinds raw coal into coal powder and dries it at the same time. Pulverizing and drying output refers to the amount of raw coal that the system can grind and dry per unit time. Improving pulverizing and drying output means that more raw coal can be processed in the same amount of time, thereby improving the operating efficiency of the boiler.

[0004] The existing coal-fired boilers improve the efficiency of coal grinding and drying by optimizing the design and operating parameters of the coal mill, such as roller loading force, grinding disc speed, etc. The intelligent control system is introduced to monitor the operating status of the pulverizing system in real time, and automatically adjust the operating parameters according to factors such as load changes and coal type changes to maintain efficient pulverizing and drying output.

[0005] In recent years, coal-fired boiler technology has made significant progress in improving efficiency and energy conservation and emission reduction. Especially under low-load operation, by optimizing the design and operating parameters of the coal mill, such as adjusting the roller loading force and the grinding disc speed, the operating efficiency and stability of the boiler have been improved to a certain extent. In addition, the introduction of intelligent control systems provides technical support for real-time monitoring and adjustment of the operating status of the pulverizing system, allowing the boiler to be adjusted in real time according to changes in load and coal type.

[0006] Although the existing coal-fired boilers can improve the efficiency of coal grinding and drying by optimizing the design and operating parameters of the coal mills and introducing intelligent control systems, there are still the following technical pain points: changes in coal quality, such as differences in moisture, ash, volatile matter, etc., will directly affect the efficiency of coal grinding and drying. The intelligent control system needs to be able to monitor the changes in coal quality in real time and quickly adjust the operating parameters to adapt to these changes. For this purpose, a control system and method for improving the low-load pulverizing and drying output of coal-fired boilers have been developed. Summary of the invention

[0007] The purpose of the present invention is to provide a control system and method for improving the low-load pulverizing and drying output of a coal-fired boiler, so as to solve the problem that changes in coal quality, such as differences in moisture, ash, volatile matter, etc., will directly affect the efficiency of coal grinding and drying.

[0008] In a first aspect, the present invention provides a control system for improving the low-load pulverizing and drying output of a coal-fired boiler, comprising: a central control system, a device end, a user end, and a background control end, wherein the central control system establishes communication connections with the device end, the user end, and the background control end, and the central control system processes data from the user end and the background control end, generates optimized control parameters, and sends them to the device end, and the device end executes the optimized control parameters;

[0009] An acquisition unit acquires coal storage information, divides the coal storage information into detection areas, obtains the coal area to be detected, performs ash and moisture detection according to the coal area to be detected, and obtains coal ash and moisture data;

[0010] The acquisition unit is mainly responsible for monitoring the coal storage bin and obtaining the storage information of the coal in real time. First, through the IoT sensor network, key data such as the amount of coal, temperature and humidity in the coal storage bin are collected. The data is transmitted to the central control system in real time through wireless communication technology. Next, the coal in the storage bin is divided into regions using image recognition technology. A machine vision system or drone can be used for aerial photography, and then the coal accumulation area is identified through image processing algorithms to determine the coal area to be tested. After determining the area to be tested, use detection equipment such as ash analyzers and moisture meters to test the ash and moisture content of the coal in the test area to obtain accurate coal ash and moisture data.

[0011] The data processing unit substitutes the coal ash and moisture data into the preset fuzzy control model and outputs the optimized control parameters, which include the operating parameters of the coal mill and the operating parameters of the drying system;

[0012] After obtaining the ash and moisture data of the coal, the data processing unit uses this data to optimize the control parameters of the coal mill and drying system. First, the ash and moisture data of the coal are input into a preset fuzzy control model. This model processes the input data through a fuzzy logic algorithm and outputs optimized control parameters. The optimized control parameters are adjusted according to the current coal quality (determined by the ash and moisture content) to ensure that the coal mill and drying system can operate in the most efficient manner. The output optimized control parameters may include the speed, feed rate, grinding pressure, etc. of the coal mill, as well as the hot air temperature and air volume of the drying system.

[0013] The acquisition unit collects the best coal grinding and drying parameters under different coal qualities, builds a coal quality data database, performs data analysis on the data in the coal quality data database, and obtains the correlation between the coal quality data and the system control parameters;

[0014] The main task of the acquisition unit is to collect the best grinding and drying parameters under different coal qualities and build a coal quality database. Through experiments and tests on different types of coal, the best processing parameters for various coal qualities under different conditions are determined. The data is collated and stored in the database for subsequent data analysis and parameter optimization. In addition, the acquisition unit also conducts in-depth analysis of the data in the database to find the correlation between coal quality data and system control parameters.

[0015] A matching unit receives the expected dryness value, matches the expected dryness value with the coal quality data, and retrieves the system control parameters corresponding to the coal quality data according to the matching result of the expected dryness value and the coal quality data to obtain the expected dryness value control parameters;

[0016] The matching unit is responsible for receiving the expected dryness value set by the user, which represents the dryness level that the user wants the coal to achieve. Then, the matching unit will match the expected dryness value with the data in the coal quality database to find the coal quality data closest to the expected dryness value and its corresponding optimal control parameters. Finally, the matching unit retrieves the system control parameters corresponding to the matching coal quality data from the database and uses them as input for the subsequent control system.

[0017] The execution unit executes the expected dryness value control parameters in the control system and detects the dryness of the coal after pulverizing. If it does not meet the expected dryness value, the optimized control parameters including the operating parameters of the coal mill and the operating parameters of the drying system are executed in the control system.

[0018] The execution unit executes the expected dryness value control parameters determined by the previous unit in the control system. The expected dryness value control parameters are transmitted to the control systems of the coal mill and the drying system to adjust the operating status of the equipment. During the execution process, the execution unit will also perform real-time detection of the dryness of the coal after pulverization to ensure that the dryness of the coal meets the expected value. If the detected dryness does not meet the expected value, the execution unit will immediately adjust the parameters of the control system, execute the optimized control parameters obtained by the fuzzy control model, and adjust the operating parameters of the coal mill and the operating parameters of the drying system in real time until the dryness of the coal reaches the expected value.

[0019] Furthermore, the present invention provides a control system for improving the low-load pulverizing and drying output of a coal-fired boiler, an acquisition unit, comprising:

[0020] The data generation unit uses IoT sensors to obtain coal storage information, monitor the coal quantity, temperature, and humidity of the coal storage bin in real time, and transmits this data to the central control system through wireless communication technology;

[0021] IoT sensors placed in coal storage silos can monitor coal quantity, temperature, and humidity in real time. Sensors include the following types:

[0022] Coal quantity sensor: used to monitor the amount of coal in the coal storage bin in real time to ensure inventory accuracy and timely replenishment.

[0023] Temperature sensors: These sensors are used to measure the temperature of coal storage bins to prevent safety hazards caused by excessive temperatures. They also help to understand the storage status of the coal.

[0024] Humidity Sensor: Humidity sensor is used to detect the humidity level in the storage silo. Humidity is an important factor affecting the quality of coal, so it is necessary to monitor it.

[0025] In addition, according to actual needs, other types of sensors, such as smoke sensors, may be included to provide more comprehensive safety monitoring. The application of these sensors, combined with the Internet of Things technology, can achieve real-time and remote monitoring of the coal storage bin environment, improving management efficiency and safety.

[0026] Please note that the specific sensor model and brand may vary depending on the actual application scenario and requirements. When selecting a sensor, factors such as its accuracy, stability, durability, and compatibility with existing systems should be considered.

[0027] The graphic detection unit divides the coal storage information into detection areas based on the image recognition technology. The coal storage information includes the location information of the coal in the storage bin. The area division is performed according to the location information of the coal in the storage bin. The image data is processed by the machine learning algorithm to automatically divide the coal area to be detected, and the coal area to be detected is obtained:

[0028] The detection unit performs ash and moisture detection according to the coal-fired area to be detected. In the designated coal-fired area to be detected, ash and moisture detection equipment is used to perform sampling and analysis. The detection equipment determines the ash and moisture content of the coal in the coal-fired area to be detected through near-infrared spectroscopy analysis to obtain the ash and moisture data of the coal in the coal-fired area to be detected.

[0029] Furthermore, the present invention provides a control system for improving the low-load pulverizing and drying output of a coal-fired boiler, and a data processing unit, comprising:

[0030] A model building unit builds a fuzzy control model, the fuzzy control model is used to receive the ash content and moisture data of the coal in the coal-burning area to be detected as input, and uses fuzzy logic to process the data to obtain the output result of the fuzzy control model;

[0031] The model optimization unit adjusts the coal mill operating parameters and the drying system operating parameters according to the output results of the fuzzy control model to obtain optimized coal mill operating parameters and the drying system operating parameters.

[0032] Furthermore, the present invention provides a control system for improving the low-load pulverizing and drying output of a coal-fired boiler, and a collection unit, comprising:

[0033] Database construction unit, collecting the best coal grinding and drying parameters under different coal qualities for building coal quality database;

[0034] The data labeling unit creates labels for different coal qualities in the coal quality database, and based on the coal quality labels, establishes the optimal coal grinding and drying parameter sequence corresponding to the labels;

[0035] The data mining unit performs data analysis on the data in the coal quality data database, and uses data mining technology to analyze the data in the database to obtain the correlation between the coal quality data and the system control parameters.

[0036] Furthermore, the present invention provides a control system for improving the low-load pulverizing and drying output of a coal-fired boiler, a matching unit, comprising:

[0037] The receiving unit receives the expected dryness value from the user end, where the dryness value is the dryness degree of the pulverized coal that the user expects to achieve;

[0038] The data analysis unit matches the received expected dryness value with the data in the coal quality database, and finds the coal quality data closest to the expected dryness value and its corresponding optimal control parameters according to the matching result;

[0039] The data retrieval unit retrieves the expected dryness value control parameters corresponding to the matching coal quality data from the database, and the expected dryness value control parameters are used for the operation of the coal mill and the drying system.

[0040] Furthermore, the present invention provides a control system for improving the low-load pulverizing and drying output of a coal-fired boiler, and an execution unit, comprising:

[0041] A data input unit inputs the matched expected drying value control parameter into the control system for execution;

[0042] The data adjustment unit, the control system adjusts the operating state of the coal mill and the drying system according to the expected dryness value control parameters;

[0043] The parameter adjustment unit detects the dryness of the pulverized coal after the coal grinding and drying process is completed. If the detected dryness does not meet the expected value, the optimized control parameters obtained by the fuzzy control model are executed to adjust the operating parameters of the coal mill and the parameters of the drying system.

[0044] In a second aspect, the present invention provides a control method for improving the low-load pulverizing and drying output of a coal-fired boiler, comprising:

[0045] Acquire coal storage information, divide the coal storage information into detection areas, obtain the coal area to be detected, perform ash and moisture detection on the coal area to be detected, and obtain coal ash and moisture data;

[0046] Substitute the coal ash and moisture data into the preset fuzzy control model to obtain the control parameters of the coal grinding and drying system;

[0047] Collect the best coal grinding and drying parameters under different coal qualities, build a coal quality data database, analyze the data in the coal quality data database, and obtain the correlation between coal quality data and system control parameters;

[0048] Receiving an expected dryness value, matching the expected dryness value with coal quality data, and retrieving system control parameters corresponding to the coal quality data according to the matching result of the expected dryness value and the coal quality data to obtain the expected dryness value control parameters;

[0049] The expected dryness value control parameters are executed in the control system, and the dryness of the coal after pulverizing is tested. If it does not meet the expected dryness value, the hot air temperature and air volume control parameters of the drying system are optimized. If it meets the expected dryness value, after the coal grinding in the tested coal-burning area is completed, the new coal storage information is re-divided into detection areas.

[0050] The beneficial effects of the present invention are as follows: The present invention provides a control system and method for improving the low-load pulverizing and drying output of a coal-fired boiler, aiming to solve the problem of the impact of coal quality changes on coal grinding and drying efficiency. The control system for improving the low-load pulverizing and drying output of a coal-fired boiler includes a central control system, an equipment end, a user end, and a background control end. Through the collaborative work of each end, accurate detection of coal quality, intelligent processing of data, and optimization adjustment of control parameters are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0052] Figure 1 A schematic diagram of a method flow chart provided by an embodiment of the present invention.

[0053] Figure 2 The present invention provides a flow chart of the prior art system.

[0054] Figure 3 It is a process system diagram of the embodiment of the present invention during actual use.

[0055] Figure numbers: 1. Boiler; 2. High-pressure cylinder of steam turbine; 3. No. 1 high-pressure heater; 4. First-stage extraction steam isolation valve; 5. Low-temperature feed water; 6. High-temperature feed water; 7. Main steam; 8. First-stage extraction steam; 9. Air preheater; 10. Cold air; 11. Hot secondary air at the outlet of air preheater; 12. Hot primary air at the outlet of air preheater; 13. Coal mill; 14. Primary air at the outlet of mill; 15. Desuperheater; 16. Superheated steam at the outlet of hot air heat exchanger; 17. Desuperheating water; 18. Bypass superheated steam; 19. Desuperheated and reduced-pressure superheated steam; 20. Hot air at the outlet of hot air heat exchanger; 21. Hot air exchanger; 22. Bypass superheated steam isolation valve; 23. Reduced-pressure superheated steam; 24. Desuperheating water regulating valve; 25. Desuperheating water isolation valve; 26. Economizer; 27. Low-temperature superheater; 28. Medium-temperature superheater; 29. ​​High-temperature superheater. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The technical solutions provided by the embodiments of the present invention are described in detail below in conjunction with the drawings.

[0057] In a first aspect, the present invention provides a control system for improving the low-load pulverizing and drying output of a coal-fired boiler, comprising: a central control system, a device end, a user end, and a background control end, wherein the central control system establishes communication connections with the device end, the user end, and the background control end, and the central control system processes data from the user end and the background control end, generates optimized control parameters, and sends them to the device end, and the device end executes the optimized control parameters;

[0058] An acquisition unit acquires coal storage information, divides the coal storage information into detection areas, obtains the coal area to be detected, performs ash and moisture detection according to the coal area to be detected, and obtains coal ash and moisture data;

[0059] The acquisition unit is mainly responsible for monitoring the coal storage bin and obtaining the storage information of the coal in real time. First, through the IoT sensor network, key data such as the amount of coal, temperature and humidity in the coal storage bin are collected. The data is transmitted to the central control system in real time through wireless communication technology. Next, the coal in the storage bin is divided into regions using image recognition technology. A machine vision system or drone can be used for aerial photography, and then the coal accumulation area is identified through image processing algorithms to determine the coal area to be tested. After determining the area to be tested, use detection equipment such as ash analyzers and moisture meters to test the ash and moisture content of the coal in the test area to obtain accurate coal ash and moisture data.

[0060] The data processing unit substitutes the coal ash and moisture data into the preset fuzzy control model and outputs the optimized control parameters, which include the operating parameters of the coal mill and the operating parameters of the drying system;

[0061] After obtaining the ash and moisture data of the coal, the data processing unit uses this data to optimize the control parameters of the coal mill and drying system. First, the ash and moisture data of the coal are input into a preset fuzzy control model. This model processes the input data through a fuzzy logic algorithm and outputs optimized control parameters. The optimized control parameters are adjusted according to the current coal quality (determined by the ash and moisture content) to ensure that the coal mill and drying system can operate in the most efficient manner. The output optimized control parameters may include the speed, feed rate, grinding pressure, etc. of the coal mill, as well as the hot air temperature and air volume of the drying system.

[0062] The acquisition unit collects the best coal grinding and drying parameters under different coal qualities, builds a coal quality data database, performs data analysis on the data in the coal quality data database, and obtains the correlation between the coal quality data and the system control parameters;

[0063] The main task of the acquisition unit is to collect the best grinding and drying parameters under different coal qualities and build a coal quality database. Through experiments and tests on different types of coal, the best processing parameters for various coal qualities under different conditions are determined. The data is collated and stored in the database for subsequent data analysis and parameter optimization. In addition, the acquisition unit also conducts in-depth analysis of the data in the database to find the correlation between coal quality data and system control parameters.

[0064] A matching unit receives the expected dryness value, matches the expected dryness value with the coal quality data, and retrieves the system control parameters corresponding to the coal quality data according to the matching result of the expected dryness value and the coal quality data to obtain the expected dryness value control parameters;

[0065] The matching unit is responsible for receiving the expected dryness value set by the user, which represents the dryness level that the user wants the coal to achieve. Then, the matching unit will match the expected dryness value with the data in the coal quality database to find the coal quality data closest to the expected dryness value and its corresponding optimal control parameters. Finally, the matching unit retrieves the system control parameters corresponding to the matching coal quality data from the database and uses them as input for the subsequent control system.

[0066] The execution unit executes the expected dryness value control parameters in the control system and detects the dryness of the coal after pulverizing. If it does not meet the expected dryness value, the optimized control parameters including the operating parameters of the coal mill and the operating parameters of the drying system are executed in the control system.

[0067] The execution unit executes the expected dryness value control parameters determined by the previous unit in the control system. The expected dryness value control parameters are transmitted to the control systems of the coal mill and the drying system to adjust the operating status of the equipment. During the execution process, the execution unit will also perform real-time detection of the dryness of the coal after pulverization to ensure that the dryness of the coal meets the expected value. If the detected dryness does not meet the expected value, the execution unit will immediately adjust the parameters of the control system, execute the optimized control parameters obtained by the fuzzy control model, and adjust the operating parameters of the coal mill and the operating parameters of the drying system in real time until the dryness of the coal reaches the expected value.

[0068] The fuzzy control model is used for the optimization control system of coal drying and grinding. The specific scheme of the fuzzy control model is:

[0069] Input variables: Ash Content: The range is 0-50%, which is used to indicate the ash content in coal.

[0070] Coal moisture content (Moisture Content): The range is 0-50%, used to indicate the moisture content in coal.

[0071] Output variables: Mill Speed ​​(MillSpeed): ranges from 0-100%, indicating the operating speed of the mill. Drying Temperature (DryingTemperature): ranges from 0-300 degrees Celsius, indicating the hot air temperature of the drying system.

[0072] Fuzzification: For the input and output variables, we define the following fuzzy sets:

[0073] Coal ash content: Low, Medium, High

[0074] Coal moisture: Low, Medium, High

[0075] Coal mill speed: Low, Medium, High

[0076] Drying temperature: Low, Medium, High

[0077] According to the ash and moisture content of the coal, a suitable membership function can be defined for the fuzzy set, such as a triangle membership function or a trapezoidal membership function.

[0078] Rule base: Define a set of fuzzy control rules to adjust the coal mill speed and drying temperature. Here are some example rules:

[0079] If the coal ash content is low and the coal moisture is low, the pulverizer speed is high and the drying temperature is low.

[0080] If the ash content of the coal is medium and the moisture content of the coal is medium, the pulverizer speed is medium and the drying temperature is medium.

[0081] If the coal ash content is high and the coal moisture content is high, the pulverizer speed is low and the drying temperature is high.

[0082] Other possible combination rules are also included.

[0083] Fuzzy Reasoning and Defuzzification:

[0084] Based on the actual value of the input variable and the fuzzy control rules, a fuzzy inference method (such as the Mamdani inference method) is used to determine the fuzzy value of the output variable. Then, the fuzzy value is converted into the actual control parameter value through a defuzzification method (such as the maximum membership method, the centroid method, or the weighted average method).

[0085] Implementation steps: Obtain coal ash and moisture data in real time. Fuzzify these data and determine their membership in their respective fuzzy sets. Apply fuzzy control rules for fuzzy reasoning to obtain fuzzy values ​​of coal mill speed and drying temperature. Defuzzify these fuzzy values ​​to obtain specific control parameter values. Send these control parameter values ​​to the control system of the coal mill and drying system for real-time adjustment.

[0086] The fuzzy control model of the technical solution of the present application can be dynamically adjusted according to the actual coal quality and drying requirements to achieve a more efficient coal grinding and drying process.

[0087] Specifically, the present invention provides a control system for improving the low-load pulverizing and drying output of a coal-fired boiler, and an acquisition unit, comprising:

[0088] The data generation unit uses IoT sensors to obtain coal storage information, monitor the coal quantity, temperature, and humidity of the coal storage bin in real time, and transmits this data to the central control system through wireless communication technology;

[0089] The graphic detection unit divides the coal storage information into detection areas based on the image recognition technology. The coal storage information includes the location information of the coal in the storage bin. The area division is performed according to the location information of the coal in the storage bin. The image data is processed by the machine learning algorithm to automatically divide the coal area to be detected, and the coal area to be detected is obtained:

[0090] The detection unit performs ash and moisture detection according to the coal-fired area to be detected. In the designated coal-fired area to be detected, ash and moisture detection equipment is used to perform sampling and analysis. The detection equipment determines the ash and moisture content of the coal in the coal-fired area to be detected through near-infrared spectroscopy analysis to obtain the ash and moisture data of the coal in the coal-fired area to be detected.

[0091] Specifically, the present invention provides a control system for improving the low-load pulverizing and drying output of a coal-fired boiler, and a data processing unit, comprising:

[0092] A model building unit builds a fuzzy control model, the fuzzy control model is used to receive the ash content and moisture data of the coal in the coal-burning area to be detected as input, and uses fuzzy logic to process the data to obtain the output result of the fuzzy control model;

[0093] The model optimization unit adjusts the coal mill operating parameters and the drying system operating parameters according to the output results of the fuzzy control model to obtain optimized coal mill operating parameters and the drying system operating parameters.

[0094] Specifically, the present invention provides a control system for improving the low-load pulverizing and drying output of a coal-fired boiler, and a collection unit, comprising:

[0095] Database construction unit, collecting the best coal grinding and drying parameters under different coal qualities for building coal quality database;

[0096] The data labeling unit creates labels for different coal qualities in the coal quality database, and based on the coal quality labels, establishes the optimal coal grinding and drying parameter sequence corresponding to the labels;

[0097] The data mining unit performs data analysis on the data in the coal quality data database, and uses data mining technology to analyze the data in the database to obtain the correlation between the coal quality data and the system control parameters.

[0098] Specifically, the present invention provides a control system for improving the low-load pulverizing and drying output of a coal-fired boiler, a matching unit, comprising:

[0099] The receiving unit receives the expected dryness value from the user end, where the dryness value is the dryness degree of the pulverized coal that the user expects to achieve;

[0100] The data analysis unit matches the received expected dryness value with the data in the coal quality database, and finds the coal quality data closest to the expected dryness value and its corresponding optimal control parameters according to the matching result;

[0101] The data retrieval unit retrieves the expected dryness value control parameters corresponding to the matching coal quality data from the database, and the expected dryness value control parameters are used for the operation of the coal mill and the drying system.

[0102] Specifically, the present invention provides a control system for improving the low-load pulverizing and drying output of a coal-fired boiler, and an execution unit, comprising:

[0103] A data input unit inputs the matched expected drying value control parameter into the control system for execution;

[0104] The data adjustment unit, the control system adjusts the operating state of the coal mill and the drying system according to the expected dryness value control parameters;

[0105] The parameter adjustment unit detects the dryness of the pulverized coal after the coal grinding and drying process is completed. If the detected dryness does not meet the expected value, the optimized control parameters obtained by the fuzzy control model are executed to adjust the operating parameters of the coal mill and the parameters of the drying system.

[0106] In a second aspect, the present invention provides a control method for improving the low-load pulverizing and drying output of a coal-fired boiler, comprising:

[0107] In step S101, coal storage information is obtained, and the coal storage information is divided into detection areas to obtain the coal area to be detected, and ash and moisture detection is performed according to the coal area to be detected to obtain coal ash and moisture data;

[0108] In step S101, first, various information about coal storage is obtained in real time through the sensor network deployed in the coal storage bin, including but not limited to the stacking density, temperature distribution, humidity, etc. of the coal. Then, the acquired data is analyzed using image processing technology, and the storage area is divided into several coal areas to be tested according to the stacking form and physical properties of the coal. For each area to be tested, professional testing equipment, such as infrared spectrometers and moisture measuring instruments, is used to perform accurate ash and moisture content testing. Through testing, the ash and moisture data of each coal area to be tested can be obtained, providing basic data support for subsequent optimization of control parameters.

[0109] In step S102, the coal ash and moisture data are substituted into a preset fuzzy control model to obtain control parameters of the coal grinding and drying system;

[0110] In step S102, the coal ash and moisture data obtained in step S101 are used as input and substituted into a pre-set fuzzy control model. The fuzzy control model is constructed based on expert experience and historical data, and can intelligently calculate the optimal control parameters of the coal grinding and drying system according to the ash and moisture content of different coals. The control parameters include but are not limited to the rotation speed, feed speed, discharge particle size of the coal mill, and the hot air temperature and air volume of the drying system. Through the operation of the fuzzy control model, a set of optimized control parameters for the current coal quality is obtained to improve the efficiency and quality of coal grinding and drying.

[0111] In step S103, the optimal coal grinding and drying parameters under different coal qualities are collected, a coal quality data database is constructed, and data in the coal quality data database is analyzed to obtain the correlation between the coal quality data and the system control parameters;

[0112] In step S103, through extensive experiments and tests, the optimal parameters for coal grinding and drying under different coal quality conditions are collected. The data is integrated into a coal quality data database, which contains various properties such as coal type, ash content, moisture, volatile matter, and the corresponding optimal coal grinding and drying parameters. Using data analysis techniques, such as association rule mining and cluster analysis, this database is deeply mined to reveal the inherent correlation between coal quality data and system control parameters. These correlations can provide decision support for subsequent control systems, enabling them to automatically adjust control parameters according to different coal qualities.

[0113] In step S104, the expected dryness value is received, the expected dryness value is matched with the coal quality data, and according to the matching result of the expected dryness value and the coal quality data, the system control parameter corresponding to the coal quality data is retrieved to obtain the expected dryness value control parameter;

[0114] In step S104, the system receives the expected dryness value set by the user, which represents the coal dryness that the user hopes to achieve. Then, the system matches the expected dryness value with the data in the coal quality database, and finds the coal quality data record closest to the expected dryness value through comparison and analysis. According to the corresponding optimal system control parameters in these data records, a set of expected dryness value control parameters can be obtained. The parameters will be used in the subsequent control system to ensure that the dryness of the coal can meet the user's expectations.

[0115] In step S105, the expected dryness value control parameter is executed in the control system, and the dryness of the coal after pulverizing is detected. If it does not meet the expected dryness value, the hot air temperature and air volume control parameters of the drying system are optimized. If it meets the expected dryness value, after the coal grinding in the coal-fired area to be detected is completed, the new coal storage information is re-divided into detection areas.

[0116] In step S105, the expected dryness value control parameter obtained in step S104 is input into the control system to guide the coal grinding and drying process. After the coal is ground and dried, we perform real-time detection of its dryness to ensure that it meets the expected dryness value set by the user. If the test result does not meet expectations, we will optimize and adjust the control parameters such as the hot air temperature and air volume of the drying system to improve the drying efficiency and quality of the coal. If the test result meets the expected dryness value, it means that the current control system parameter settings are reasonable. In this case, we will continue to monitor the status of the coal storage bin, and after the coal grinding in the current coal area to be detected is completed, the new coal storage information will be re-divided into detection areas for the next round of optimization control process.

[0117] This technical solution aims to solve the problem of the impact of coal quality changes on coal grinding and drying efficiency by constructing a control system that improves the low-load pulverizing and drying output of coal-fired boilers. The control system that improves the low-load pulverizing and drying output of coal-fired boilers includes a central control system, equipment end, user end, and background control end. Through the collaborative work of each end, accurate detection of coal quality, intelligent data processing, and optimization and adjustment of control parameters can be achieved.

[0118] First, the coal burning information is obtained in real time through the acquisition unit, and the coal burning area is accurately divided using image recognition technology and machine learning algorithms. The ash and moisture content of the coal in a specific area is then tested to obtain accurate data.

[0119] Next, the data processing unit puts the coal ash and moisture data into the preset fuzzy control model, and outputs the optimized control parameters through fuzzy logic processing. The optimized control parameters include the operating parameters of the coal mill and the operating parameters of the drying system. This processing method can effectively deal with the uncertainty of coal quality and improve the robustness of the control system.

[0120] In addition, the acquisition unit built a coal quality database by collecting the best coal grinding and drying parameters under different coal qualities, and analyzed the correlation between coal quality data and system control parameters through data mining technology. This provides data support for subsequent parameter matching and optimization.

[0121] In the matching unit, the system receives the expected drying value set by the user and matches it with the data in the coal quality database to find the closest coal quality data and its corresponding optimal control parameters. This matching mechanism ensures that the system can quickly adjust the control parameters according to user needs.

[0122] Finally, the execution unit is responsible for executing the expected dryness value control parameters matched in the control system, and detecting the dryness of the pulverized coal after the pulverization and drying process is completed. If the detected dryness does not meet the expected value, the system will immediately execute the optimized control parameters obtained by the fuzzy control model to adjust the operating parameters of the coal mill and the parameters of the drying system. This solves the problem that the efficiency of coal pulverization and drying is directly affected by changes in coal quality, such as different contents of moisture, ash, and volatile matter.

[0123] The control system for improving the low-load pulverizing and drying output of the coal-fired boiler executes the expected dryness value control parameter and is applied to the following device, and the specific method is as follows: The control system for improving the low-load pulverizing and drying output of the coal-fired boiler executes the expected dryness value control parameter and is applied to the following device, and the specific method is as follows, including main steam 7, air preheater 9, hot air heat exchanger 21, pressure reducing regulating valve 12, desuperheater 15, desuperheating water 17, desuperheating water regulating valve 24, a first stage extraction steam 8, No. 1 high-pressure heater 3 and coal mill 13;

[0124] The hot air heat exchanger 21 is arranged in the hot primary air duct between the air preheater 9 and the coal mill 13. After the cold air 10 passes through the air preheater 9, a part of it enters the boiler 1 as the hot secondary air 11 at the outlet of the air preheater to participate in the combustion, and the other part enters the hot air heat exchanger 21 to be heated again and becomes the hot air 20 at the outlet of the hot air heat exchanger to enter the coal mill 13 to dry the raw coal, thereby increasing the temperature of the primary air 14 at the outlet of the coal mill 13. The primary air 14 at the outlet of the coal mill 13 after the temperature is increased enters the boiler 1 to be burned;

[0125] Extracting part of the superheated steam from the outlet of the medium-temperature superheater 28 arranged in the boiler 1 as bypass superheated steam 18;

[0126] The bypass superheated steam 18 is decompressed by the pressure reducing regulating valve 12 and then desuperheated by the desuperheater 15 to become desuperheated and decompressed superheated steam 19;

[0127] The desuperheated steam 19 enters the hot air heat exchanger 21, heats the hot primary air at the outlet of the air preheater to become the hot air 20 at the outlet of the hot air heat exchanger, and the desuperheated steam 19 after heat release becomes the superheated steam 16 at the outlet of the hot air heat exchanger;

[0128] When the system is running, the first stage extraction steam isolation valve 4 is closed, and the superheated steam 16 at the outlet of the hot air heat exchanger replaces the first stage extraction steam 8 to enter the No. 1 high-pressure heater 3 to heat the low-temperature feed water 5. The low-temperature feed water 5 is heated by the No. 1 high-pressure heater 3 and becomes high-temperature feed water 6, which is finally sent to the boiler 1.

[0129] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0130] The original system runs as shown in the attached Figure 1 As shown:

[0131] After entering the boiler 1, the high-temperature feed water 6 is heated by the economizer 26, the low-temperature superheater 27, the medium-temperature superheater 28, and the high-temperature superheater 29 to become the main steam 7. The main steam 7 at the outlet of the high-temperature superheater 29 enters the high-pressure cylinder 2 of the steam turbine to do work; the first-stage extraction steam 8 extracted from the high-pressure cylinder 2 of the steam turbine enters the No. 1 high-pressure heater 3 after passing through the first-stage extraction steam isolation valve 4, and the low-temperature feed water 5 is heated by the No. 1 high-pressure heater 3 to become the high-temperature feed water 6, and the high-temperature feed water 6 is sent to the economizer 26 in the boiler 1. The cold air 10 is heated by the air preheater 9 to become the hot secondary air 11 at the outlet of the air preheater and the hot primary air at the outlet of the air preheater. The hot secondary air 11 at the outlet of the air preheater is sent to the boiler 1 to participate in the combustion; the hot primary air at the outlet of the air preheater enters the coal mill 13 to dry the raw coal, and the mill outlet primary air 14 at the outlet of the coal mill 13 enters the boiler 1 for parameter setting. .

[0132] The system and method disclosed in the present invention are as follows Figure 2 As shown:

[0133] Under low load conditions, part of the superheated steam is taken from the outlet of the medium-temperature superheater 28 arranged in the boiler 1 as the bypass superheated steam 18, the original first stage extraction steam isolation valve 4 is closed, the first stage extraction steam 8 is isolated, and the first stage extraction steam 8 is no longer extracted from the high-pressure cylinder 2 of the steam turbine;

[0134] The bypass superheated steam 18 passes through the bypass superheated steam isolation valve 22 and is decompressed by the pressure reducing regulating valve 12, and becomes the decompressed superheated steam 23 after being decompressed;

[0135] The desuperheated water 17 passes through the desuperheated water isolation valve 25, and the desuperheated water regulating valve 24 is used to adjust the flow rate. The desuperheated bypass superheated steam 23 passes through the desuperheater 15 and is desuperheated by the desuperheated water 17, and finally the bypass superheated steam 18 is converted into desuperheated and decompressed superheated steam 19.

[0136] The desuperheated steam 19 is sent to the hot air heat exchanger 21, which is arranged between the air preheater 9 and the coal mill 13. The hot air heat exchanger 21 heats the hot primary air at the outlet of the air preheater by using the desuperheated steam 19, so that the temperature of the hot primary air at the outlet of the air preheater is increased to become the hot air 20 at the outlet of the hot air heat exchanger. The hot air 20 at the outlet of the hot air heat exchanger is sent to the coal mill 13 to dry the raw coal, and the primary air 14 at the outlet of the coal mill 13 is sent to the boiler 1 for combustion.

[0137] The cooled and reduced-pressure superheated steam 19 becomes the superheated steam 16 at the outlet of the hot air heat exchanger. The superheated steam 16 at the outlet of the hot air heat exchanger is sent to the No. 1 high-pressure heater 3, thereby replacing the original first-stage extraction steam 8 to heat the low-temperature feed water 5. The low-temperature feed water 5 is heated by the No. 1 high-pressure heater 3 and becomes the high-temperature feed water 6. The high-temperature feed water 6 is finally sent to the economizer 26 in the boiler 1.

[0138] When the system is operating normally, the pressure of the first extraction steam 8 changes with the change of the unit load. Taking a 350MW supercritical unit as an example, the pressure of the first extraction steam 8 is 11MPa at 100%THA load, and the pressure of the first extraction steam 8 is about 3MPa at 30%THA load. Since the No. 1 high-pressure heater 3 is a condensing heat exchanger, the temperature of its outlet high-temperature feed water 6 depends on the feed water end difference of the No. 1 high-pressure heater 3, and the feed water end difference refers to the difference between the saturated temperature at the inlet steam pressure of the No. 1 high-pressure heater 3 and the outlet high-temperature feed water 6 temperature. Therefore, the temperature of the high-temperature feed water 6 at the outlet of the No. 1 high-pressure heater 3 continues to decrease with the decrease of the load. In addition, as the load decreases, the temperature of the hot primary air entering the coal mill 13 gradually decreases. The hot primary air temperature is about 220℃ at 30%THA load, which is nearly 100℃ lower than that of 100%THA load. The primary air temperature 14 at the mill outlet is only about 60℃, and the drying output of the coal mill 13 is seriously affected. This problem is more obvious when burning high-moisture coal.

[0139] In the system and method disclosed in the present invention, part of the superheated steam is extracted from the outlet of the medium-temperature superheater 28 arranged in the boiler 1 as the bypass superheated steam 18, and the bypass superheated steam 19 after being cooled and reduced in pressure first uses its superheat to heat the hot primary air at the outlet of the air preheater through the hot air heat exchanger 21, thereby raising the temperature of the hot primary air at the outlet of the air preheater to above 290°C; when the type of coal is not changed, the temperature of the primary air 14 at the mill outlet can be raised from 60°C to 70°C, thereby greatly improving the combustion stability in the boiler 1; and when the temperature of the primary air 14 at the mill outlet is maintained unchanged, the moisture content of the coal entering the pulverizer 13 can be increased by 5%, thereby improving the economical blending ratio of the unit coal.

[0140] On the other hand, the steam after cooling becomes the superheated steam 16 at the outlet of the hot air heat exchanger and is sent to the No. 1 high-pressure heater 3 as the steam source of the No. 1 high-pressure heater 3. The temperature and pressure of the superheated steam 16 at the outlet of the hot air heat exchanger entering the No. 1 high-pressure heater 3 can be adjusted by the cooling water regulating valve 24 and the pressure reducing regulating valve 12. Since the temperature and pressure of the superheated steam 16 at the outlet of the hot air heat exchanger are much higher than the temperature and pressure of the first stage extraction steam 8, and it has a huge superheat, the system and method disclosed in the present invention, on the one hand, realizes the goal of using the superheat of the superheated steam to heat the temperature of the primary air 14 at the mill outlet entering the boiler 1, improves the drying output of the powder making system, and reduces the coal consumption of the unit; on the other hand, it realizes the increase of the steam pressure entering the No. 1 high-pressure heater 3 under the low-load condition of the unit, thereby greatly increasing the temperature of the high-temperature feed water 6 at the outlet of the No. 1 high-pressure heater 3. After calculation, the temperature of the high-temperature feed water 6 can be increased by more than 40°C.

[0141] Those skilled in the art can clearly understand that the technology in the embodiments of the present invention can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the technical solution in the embodiments of the present invention can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present invention or certain parts of the embodiments.

[0142] The above-described embodiments of the present invention do not limit the protection scope of the present invention.

Claims

1. A control system for improving the low-load pulverizing and drying output of a coal-fired boiler, characterized in that: include: The central control system, the device end, the user end and the background control end, the central control system establishes communication connections with the device end, the user end and the background control end, the central control system processes the data of the user end and the background control end, generates optimized control parameters and sends them to the device end, and the device end executes the optimized control parameters; An acquisition unit acquires coal storage information, divides the coal storage information into detection areas, obtains the coal area to be detected, performs ash and moisture detection according to the coal area to be detected, and obtains coal ash and moisture data; The data processing unit substitutes the coal ash and moisture data into the preset fuzzy control model and outputs the optimized control parameters, which include the operating parameters of the coal mill and the operating parameters of the drying system; The acquisition unit collects the best coal grinding and drying parameters under different coal qualities, builds a coal quality data database, performs data analysis on the data in the coal quality data database, and obtains the correlation between the coal quality data and the system control parameters; A matching unit receives the expected dryness value, matches the expected dryness value with the coal quality data, and retrieves the system control parameters corresponding to the coal quality data according to the matching result of the expected dryness value and the coal quality data to obtain the expected dryness value control parameters; An execution unit executes the expected dryness value control parameters in the control system and detects the dryness of the coal after pulverizing. If the expected dryness value is not met, the optimized control parameters are executed in the control system, including the operating parameters of the coal mill and the operating parameters of the drying system; The control parameter for executing the expected drying value in the control system for improving the low-load pulverizing and drying output of a coal-fired boiler is applied to the following devices, including main steam (7), an air preheater (9), a hot air heat exchanger (21), a pressure reducing regulating valve (12), a desuperheater (15), desuperheating water (17), a desuperheating water regulating valve (24), a first stage extraction steam (8), a No. 1 high-pressure heater (3), and a coal mill (13); The hot air heat exchanger (21) is arranged in the hot primary air duct between the air preheater (9) and the coal mill (13); after the cold air (10) passes through the air preheater (9), a portion of the cold air (10) enters the boiler (1) as hot secondary air (11) at the outlet of the air preheater to participate in combustion; the other portion enters the hot air heat exchanger (21) to be heated again and becomes hot air (20) at the outlet of the hot air heat exchanger to enter the coal mill (13) to dry the raw coal and increase the temperature of the primary air (14) at the outlet of the coal mill (13); the primary air (14) at the outlet of the coal mill (13) after the temperature is increased enters the boiler (1) to be burned; extracting part of the superheated steam from the outlet of the medium-temperature superheater (28) arranged in the boiler (1) as bypass superheated steam (18); The bypass superheated steam (18) is decompressed by the pressure reducing regulating valve (12) and then desuperheated by the desuperheater (15) to become desuperheated and pressure reduced superheated steam (19); The desuperheated steam (19) enters the hot air heat exchanger (21), heats the hot primary air at the outlet of the air preheater and converts it into hot air (20) at the outlet of the hot air heat exchanger, and the desuperheated steam (19) after releasing heat becomes superheated steam (16) at the outlet of the hot air heat exchanger; When the system is in operation, the first stage extraction steam isolation valve (4) is closed, and the superheated steam (16) at the outlet of the hot air heat exchanger replaces the first stage extraction steam (8) and enters the first high-pressure heater (3) to heat the low-temperature feed water (5). The low-temperature feed water (5) is heated by the first high-pressure heater (3) and becomes high-temperature feed water (6), and is finally sent to the boiler (1). Get unit, including: The data generation unit uses IoT sensors to obtain coal storage information, monitor the coal quantity, temperature, and humidity of the coal storage bin in real time, and transmits this data to the central control system through wireless communication technology; The graphic detection unit divides the coal storage information into detection areas based on the image recognition technology. The coal storage information includes the location information of the coal in the storage bin. The area division is performed according to the location information of the coal in the storage bin. The image data is processed by the machine learning algorithm to automatically divide the coal area to be detected, and the coal area to be detected is obtained: The detection unit performs ash and moisture detection according to the coal-fired area to be detected. In the designated coal-fired area to be detected, ash and moisture detection equipment is used to perform sampling and analysis. The detection equipment measures the ash and moisture content of the coal in the coal-fired area to be detected by near-infrared spectroscopy analysis to obtain the ash and moisture data of the coal in the coal-fired area to be detected; Data processing unit, including: A model building unit builds a fuzzy control model, the fuzzy control model is used to receive the ash content and moisture data of the coal in the coal-burning area to be detected as input, and uses fuzzy logic to process the data to obtain the output result of the fuzzy control model; The model optimization unit adjusts the coal mill operating parameters and the drying system operating parameters according to the output results of the fuzzy control model to obtain the optimized coal mill operating parameters and the drying system operating parameters; The acquisition unit includes: Database construction unit, collecting the best coal grinding and drying parameters under different coal qualities for building coal quality database; The data labeling unit creates labels for different coal qualities in the coal quality database, and based on the coal quality labels, establishes the optimal coal grinding and drying parameter sequence corresponding to the labels; The data mining unit performs data analysis on the data in the coal quality data database, and uses data mining technology to analyze the data in the database to obtain the correlation between the coal quality data and the system control parameters; Matching unit, comprising: The receiving unit receives the expected dryness value from the user end, where the dryness value is the dryness degree of the pulverized coal that the user expects to achieve; The data analysis unit matches the received expected dryness value with the data in the coal quality database, and finds the coal quality data closest to the expected dryness value and its corresponding optimal control parameters according to the matching result; A data retrieval unit retrieves expected dryness value control parameters corresponding to the matching coal quality data from a database, and the expected dryness value control parameters are used for the operation of the coal mill and the drying system; Execution unit, including: A data input unit inputs the matched expected drying value control parameter into the control system for execution; The data adjustment unit, the control system adjusts the operating state of the coal mill and the drying system according to the expected drying value control parameters; The parameter adjustment unit detects the dryness of the pulverized coal after the coal grinding and drying process is completed. If the detected dryness does not meet the expected value, the optimized control parameters obtained by the fuzzy control model are executed to adjust the operating parameters of the coal mill and the parameters of the drying system.

2. A control method for improving the low-load pulverizing and drying output of a coal-fired boiler, applied to the control system for improving the low-load pulverizing and drying output of a coal-fired boiler as claimed in claim 1, characterized in that: include: Acquire coal storage information, divide the coal storage information into detection areas, obtain the coal area to be detected, perform ash and moisture detection on the coal area to be detected, and obtain coal ash and moisture data; Substitute the coal ash and moisture data into the preset fuzzy control model to obtain the control parameters of the coal grinding and drying system; Collect the best coal grinding and drying parameters under different coal qualities, build a coal quality data database, analyze the data in the coal quality data database, and obtain the correlation between coal quality data and system control parameters; Receiving an expected dryness value, matching the expected dryness value with coal quality data, and retrieving system control parameters corresponding to the coal quality data according to the matching result of the expected dryness value and the coal quality data to obtain the expected dryness value control parameters; The expected dryness value control parameters are executed in the control system, and the dryness of the coal after pulverizing is tested. If it does not meet the expected dryness value, the hot air temperature and air volume control parameters of the drying system are optimized. If it meets the expected dryness value, after the coal grinding in the tested coal-burning area is completed, the new coal storage information is re-divided into detection areas.

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