Parameter control system and method for denitration inlet and air preheater outlet of coal-fired unit

Abstract

The application relates to a coal-fired unit denitration inlet and air preheater outlet parameter control system and method, wherein the parameter monitoring system comprises: a denitration inlet measurement module, which is used for uniformly sampling flue gas from pre-set flue gas sampling ports on a plurality of measurement supports and coupling temperature field measurement; an air preheater outlet measurement module, which is used for obtaining temperature field data and oxygen content field data at the outlet flue section according to the temperature field and oxygen content distribution; a data processing and analysis module, which is used for analyzing flue gas components at the denitration inlet and the air preheater outlet of the coal-fired unit; and a control execution module, which is used for adjusting the operation parameters of the denitration system according to the temperature satisfying the preset minimum point condition and adjusting the operation parameters of the air preheater. The application realizes high-precision measurement of the temperature field and flue gas components at the denitration inlet and the air preheater outlet, and guarantees safe, efficient and environmentally-friendly operation of the coal-fired unit under a new power system.

Description

Technical Field

[0001] This application relates to the field of operation monitoring and optimization control technology for coal-fired power generating units, and in particular to a control system and method for denitrification inlet and air preheater outlet parameters of a coal-fired power generating unit. Background Technology

[0002] With the development trend of new power systems, large-scale integration of new energy sources into the grid requires coal-fired power units to undertake more peak-shaving tasks, frequently operating under prolonged peak and deep peak-shaving conditions, exhibiting a prominent peak-valley operation characteristic. This operating mode brings many challenges to coal-fired power units, among which problems such as wide-load denitrification, air preheater blockage, and high air leakage rate are particularly prominent. In related technologies, the instantaneous emissions at the flue section can be calculated based on flue gas parameters. The instantaneous emissions under different loads are compared with the preset unit emissions in the database to obtain the deviation coefficient. Based on the deviation coefficient, the real-time data for monitoring carbon emissions of coal-fired units is determined.

[0003] However, in terms of the operation of denitrification systems, the denitrification efficiency is highly dependent on the temperature of the flue gas at the denitrification inlet. Existing measuring points cannot comprehensively and accurately grasp the flue gas temperature distribution, and cannot effectively obtain the lowest temperature point at the denitrification inlet, making it difficult to ensure the stable operation of the denitrification system under wide load conditions. There are also insufficient temperature measuring points at the air preheater outlet, which cannot fully present the temperature field distribution and make it difficult to detect abnormal conditions such as air preheater blockage and air leakage in a timely manner through temperature changes. Relying solely on a single temperature or oxygen index is insufficient to comprehensively assess the health status of the air preheater and cannot provide sufficient basis for operation adjustment and maintenance, which urgently needs improvement. Summary of the Invention This application provides a control system and method for the parameters of the denitrification inlet and air preheater outlet of a coal-fired power unit. This addresses the issue that denitrification efficiency is highly dependent on the temperature of the flue gas at the denitrification inlet during denitrification system operation. When the unit is under low-load, deep peak-shaving conditions, if the flue gas temperature at the denitrification inlet is lower than the lower limit required for catalyst activity, denitrification failure will occur, leading to a significant increase in ammonia escape. The escaped ammonia reacts with sulfur trioxide in the flue gas to form ammonium bisulfate, which adheres to the surface of the air preheater, causing blockage. Furthermore, the current number of temperature measuring points at the denitrification inlet is limited, and the temperature distribution across the flue gas duct cross-section in this area is uneven. Existing measuring points cannot comprehensively and accurately grasp the flue gas temperature distribution, making it impossible to effectively obtain the lowest temperature point at the denitrification inlet and ensuring stable operation of the denitrification system under wide load conditions. For the air preheater, under low-load conditions, the exhaust gas temperature decreases, and the overall cold-end temperature of the air preheater decreases accordingly, which exacerbates blockage and corrosion at the cold end of the air preheater. Furthermore, the insufficient number of temperature measurement points at the air preheater outlet makes it impossible to fully represent the temperature field distribution, hindering the timely detection of abnormal conditions such as air preheater blockage and leakage through temperature changes. In addition, relying solely on a single temperature or oxygen level indicator is insufficient to comprehensively assess the health status of the air preheater, failing to provide adequate data for operation, regulation, and maintenance.

[0004] The first aspect of this application provides a control system for parameters at the denitrification inlet and air preheater outlet of a coal-fired power unit, comprising: a denitrification inlet measurement module, used to uniformly sample flue gas at pre-set flue gas sampling ports on the multiple measurement supports after arranging multiple measurement supports at the flue gas cross-section of the denitrification inlet of the coal-fired power unit, and to perform temperature field measurement coupling with pre-set temperature thermocouple probes on the multiple measurement supports to generate measurement data at the denitrification inlet of the coal-fired power unit; and an air preheater outlet measurement module, used to measure the temperature field at the outlet flue gas cross-section using the pre-set temperature thermocouple probes on the multiple measurement supports after arranging the multiple measurement supports at the outlet flue gas cross-section of the air preheater, and to extract flue gas using the pre-set flue gas sampling ports on the multiple measurement supports, and to measure the oxygen field distribution at the outlet flue gas cross-section through a mixing header, so as to determine the parameters based on the temperature field and the... The oxygen field distribution module obtains temperature field data and oxygen field data at the outlet flue section; the data processing and analysis module is used to calculate the temperature at which the denitrification inlet of the coal-fired unit meets the preset minimum point condition based on the measurement data, and analyze the flue gas composition at the denitrification inlet of the coal-fired unit in the mixing box to determine the nitrogen oxide distribution at the denitrification inlet of the coal-fired unit, construct a comprehensive judgment factor based on the temperature field data and oxygen field data obtained by the air preheater outlet measurement module, and determine the blockage, leakage location and leakage degree of the air preheater according to the comprehensive judgment factor; the control execution module is used to adjust the operating parameters of the denitrification system according to the temperature that meets the preset minimum point condition to optimize the operation of the denitrification system, and adjust the operating parameters of the air preheater according to the blockage, leakage location and leakage degree of the air preheater to optimize the operation of the air preheater.

[0005] Optionally, in one embodiment of this application, the denitrification inlet measurement module includes: a temperature field and flue gas composition measurement unit, used to acquire flue gas temperature and flue gas composition information at the flue section of the denitrification inlet of the coal-fired unit; and a flue gas analysis unit, used to, after setting the mixing box, mix the flue gas from each branch pipe in the mixing box after sampling at multiple points, so as to perform flue gas composition analysis on the flue gas temperature and the flue gas composition information, to determine the flue gas composition data of the denitrification inlet of the coal-fired unit, and generate the measurement data of the denitrification inlet based on the flue gas composition data.

[0006] Optionally, in one embodiment of this application, the denitrification inlet measurement module further includes: a sampling pipeline, the sampling pipeline including a flow regulating valve and a branch pipe, wherein the flow regulating valve is used to adjust the flue gas flow at the denitrification inlet of the coal-fired unit or close the branch pipe according to the target measurement requirements, and the branch pipe is configured in a dual-path manner, wherein if the first branch meets the preset fault conditions, the second branch performs single-point flue gas composition analysis according to actual needs to obtain the oxygen field distribution.

[0007] Optionally, in one embodiment of this application, the data processing and analysis module includes: a temperature field analysis unit, used to construct a temperature field distribution model based on the temperature data, and calculate the temperature at the denitrification inlet of the coal-fired power unit that meets the preset minimum point condition based on the temperature field distribution model; a flue gas composition analysis unit, used to process the flue gas composition data and single-point analysis data after mixing in the mixing box to obtain target data, and determine the nitrogen oxide distribution at the denitrification inlet of the coal-fired power unit based on the target data and the temperature data of the temperature field; and an air preheater health status assessment unit, used to construct the comprehensive judgment factor based on the temperature that meets the preset minimum point condition and the nitrogen oxide distribution, determine the abnormal state of the air preheater based on the comprehensive judgment factor, determine the blockage and leakage location of the air preheater based on the abnormal state, actual temperature and abnormal oxygen distribution area, and determine the degree of leakage based on the correspondence between the outlet temperature and oxygen content of the air preheater.

[0008] A second aspect of this application provides a method for controlling the parameters at the denitrification inlet and air preheater outlet of a coal-fired power unit, comprising the following steps: After arranging multiple measuring supports at the flue gas cross-section of the denitrification inlet of the coal-fired power unit, uniformly sampling flue gas through pre-set flue gas sampling ports on the multiple measuring supports, and coupling temperature field measurements to pre-set temperature thermocouple probes on the multiple measuring supports to generate measurement data at the denitrification inlet of the coal-fired power unit; After arranging the multiple measuring supports at the flue gas outlet cross-section of the air preheater, measuring the temperature field at the outlet flue gas cross-section using the pre-set temperature thermocouple probes on the multiple measuring supports, and extracting flue gas through the pre-set flue gas sampling ports on the multiple measuring supports, measuring the oxygen field distribution at the outlet flue gas cross-section through a mixing header, so as to determine the parameters based on the temperature field and the... The oxygen field distribution obtains temperature field data and oxygen field data at the outlet flue section; based on the measurement data, the temperature at which the denitrification inlet of the coal-fired unit meets the preset minimum point condition is calculated, and the flue gas composition at the denitrification inlet of the coal-fired unit is analyzed in the mixing chamber to determine the nitrogen oxide distribution at the denitrification inlet of the coal-fired unit; a comprehensive judgment factor is constructed based on the temperature field data and oxygen field data obtained from the air preheater outlet measurement module, and the blockage, leakage location, and leakage degree of the air preheater are determined according to the comprehensive judgment factor; the operating parameters of the denitrification system are adjusted according to the temperature meeting the preset minimum point condition to optimize the operation of the denitrification system, and the operating parameters of the air preheater are adjusted according to the blockage, leakage location, and leakage degree of the air preheater to optimize the operation of the air preheater.

[0009] Optionally, in one embodiment of this application, the step of uniformly sampling flue gas at the pre-set flue gas sampling ports on the plurality of measuring supports and performing temperature measurement coupling on at least one pre-set temperature thermocouple probe on the plurality of measuring supports to generate measurement data of the denitrification inlet of the coal-fired power unit includes: acquiring flue gas temperature and flue gas composition information at the flue section of the denitrification inlet of the coal-fired power unit; after setting the mixing box, mixing the flue gas from each branch pipe after multi-point sampling in the mixing box, performing flue gas composition analysis on the flue gas temperature and the flue gas composition information, determining the flue gas composition data of the denitrification inlet of the coal-fired power unit, and generating measurement data of the denitrification inlet based on the flue gas composition data.

[0010] Optionally, in one embodiment of this application, the step of uniformly sampling flue gas at the pre-set flue gas sampling ports on the plurality of measuring supports further includes: when the first branch meets the preset fault conditions, the second branch performs single-point flue gas composition analysis according to actual needs to obtain the oxygen field distribution.

[0011] Optionally, in one embodiment of this application, the step of calculating the temperature at which the denitrification inlet of the coal-fired power unit meets the preset minimum point condition based on the measurement data, analyzing the flue gas composition at the denitrification inlet of the coal-fired power unit in the mixing chamber to determine the distribution of nitrogen oxides at the denitrification inlet of the coal-fired power unit, constructing a comprehensive judgment factor based on the temperature field data and oxygen field data obtained by the air preheater outlet measurement module, and determining the blockage, leakage location, and leakage degree of the air preheater according to the comprehensive judgment factor, includes: constructing a temperature field distribution model based on the temperature field data, and calculating the temperature at which the denitrification inlet of the coal-fired power unit meets the preset minimum point condition based on the temperature field distribution model. The system sets a minimum temperature condition; it processes the flue gas composition data and single-point analysis data after mixing in the mixing chamber to obtain target data, and determines the nitrogen oxide distribution at the denitrification inlet of the coal-fired unit based on the target data and the temperature field data; it constructs a comprehensive judgment factor based on the temperature that meets the minimum temperature condition and the nitrogen oxide distribution, determines the abnormal state of the air preheater based on the comprehensive judgment factor, and determines the blockage and leakage location of the air preheater based on the abnormal state, actual temperature, and abnormal oxygen distribution area, and determines the degree of leakage based on the correspondence between the outlet temperature and oxygen content of the air preheater.

[0012] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for controlling the parameters of the denitrification inlet and air preheater outlet of a coal-fired unit as described in the above embodiments.

[0013] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for controlling the parameters of the denitrification inlet and air preheater outlet of a coal-fired power unit.

[0014] This application includes a denitrification inlet measurement module, an air preheater outlet measurement module, a data processing and analysis module, and a control execution module. Through innovative measurement systems and methods, it achieves high-precision measurement of the temperature field and flue gas composition at the denitrification inlet and air preheater outlet, providing reliable data support for wide-load denitrification control and air preheater health management, ensuring the safe, efficient, and environmentally friendly operation of coal-fired units under the new power system. This solves problems in related technologies such as insufficient temperature measurement points at the denitrification inlet and air preheater outlet of coal-fired units, incomplete temperature field measurement, single flue gas composition measurement, inability to effectively achieve precise control of denitrification under wide loads, and difficulty in accurately assessing the health status of the air preheater and optimizing its adjustment.

[0015] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of a control system for denitrification inlet and air preheater outlet parameters of a coal-fired power unit according to an embodiment of this application; Figure 2 This is a schematic diagram showing the arrangement of the measuring bracket inside the flue according to an embodiment of this application; Figure 3 This is a schematic diagram of the layout of an AA / BB cross-section flue gas parameter analysis system according to an embodiment of this application; Figure 4 This is a schematic diagram of the internal structure of a measuring bracket according to an embodiment of this application; Figure 5 This is a schematic flowchart of a method for controlling the parameters of the denitrification inlet and the air preheater outlet of a coal-fired power unit according to an embodiment of this application. Figure 6 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Detailed Implementation

[0017] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0018] The following description, with reference to the accompanying drawings, illustrates a control system and method for denitrification inlet and air preheater outlet parameters of a coal-fired power unit according to embodiments of this application. Addressing the problems mentioned in the background art regarding insufficient temperature measurement points at the denitrification inlet and air preheater outlet of coal-fired power units, incomplete temperature field measurement, single flue gas composition measurement, inability to effectively achieve precise control of denitrification under wide loads, and difficulty in accurately assessing the health status of the air preheater and optimizing its adjustment, this application provides a monitoring system and control method for denitrification inlet and air preheater outlet parameters of a coal-fired power unit. This system includes a denitrification inlet measurement module, an air preheater outlet measurement module, a data processing and analysis module, and a control execution module. Through innovative measurement systems and methods, high-precision measurement of the temperature field and flue gas composition at the denitrification inlet and air preheater outlet can be achieved, providing reliable data support for wide-load denitrification control and air preheater health management, ensuring the safe, efficient, and environmentally friendly operation of coal-fired power units under the new power system. This solves the problems in related technologies, such as insufficient temperature measurement points at the denitrification inlet and air preheater outlet of coal-fired power units, incomplete temperature field measurement, single measurement of flue gas composition, inability to effectively achieve precise control of denitrification under wide loads, and difficulty in accurately assessing the health status of air preheaters and optimizing their adjustment.

[0019] Specifically, Figure 1 This is a schematic diagram of the structure of a denitrification inlet and air preheater outlet parameter control system for a coal-fired power unit, provided in an embodiment of this application.

[0020] like Figure 1 As shown, the denitrification inlet and air preheater outlet parameter control system of the coal-fired unit includes: a denitrification inlet measurement module 100, an air preheater outlet measurement module 200, a data processing and analysis module 300, and a control execution module 400.

[0021] Specifically, the denitrification inlet measurement module 100 is used to uniformly sample flue gas at the flue gas sampling ports pre-set on the multiple measurement supports after arranging multiple measurement supports at the flue gas cross-section of the denitrification inlet of the coal-fired unit, and to perform temperature field measurement coupling with the temperature thermocouple probes pre-set on the multiple measurement supports, so as to generate measurement data of the denitrification inlet of the coal-fired unit.

[0022] It is understood that the denitrification inlet measurement module 100 in this application embodiment can be a monitoring device at the inlet of the denitrification system of a coal-fired unit.

[0023] In practical implementation, the embodiments of this application can be used to arrange the measurement system. Taking a 600MW coal-fired unit as an example, 7×10 measurement supports are arranged in the inlet flue section (4m×6m) of the denitrification system according to the Chebyshev grid method. The supports are made of wear-resistant steel, and the support spacing is approximately 0.6m×0.6m. Each support is equipped with one flue gas sampling port and one temperature thermocouple probe. The flue gas sampling port and temperature thermocouple probe are arranged alternately to achieve uniform sampling of flue gas and coupling of temperature measurement. The branch pipes of each support are arranged with double DN25 stainless steel pipes. Before the branch pipes are connected to the header, an electric flow regulating valve (with shut-off function) is installed. A mixing box is connected at the outlet of the header. The mixing box is designed with a parallel structure, and mixing measurement and single-point measurement can be achieved by switching valves.

[0024] In this embodiment, measuring supports, temperature thermocouple probes, oxygen sensors, flow regulating valves, flue gas sampling pipelines, and mixing boxes are arranged according to the Chebyshev grid method at the inlet flue section of the denitrification system and the outlet flue section of the air preheater. Each device is then debugged and initialized to provide support for more comprehensive and accurate measurement of the temperature field distribution at the denitrification inlet and air preheater outlet flue sections. This effectively obtains the lowest temperature point at the denitrification inlet, providing reliable data for wide-load denitrification control, ensuring the stable operation of the denitrification system under low-load conditions, and reducing ammonia escape. Optionally, in one embodiment of this application, the denitrification inlet measurement module 100 includes: a temperature field and flue gas composition measurement unit, used to acquire flue gas temperature and flue gas composition information at the flue section of the denitrification inlet of the coal-fired unit; and a flue gas analysis unit, used to mix the flue gas from each branch pipe after multiple sampling points in the mixing box after setting up the mixing box, so as to perform flue gas composition analysis on the flue gas temperature and flue gas composition information, to determine the flue gas composition data of the denitrification inlet of the coal-fired unit, and to generate measurement data of the denitrification inlet based on the flue gas composition data.

[0025] The embodiments of this application include: (1) Temperature field and flue gas composition measurement structure: Multiple measurement supports are arranged in the inlet flue section of the denitrification system according to the Chebyshev grid method. The measurement supports are made of wear-resistant steel to resist long-term erosion and wear from the flue gas. The measurement supports are interconnected, and each support is equipped with a flue gas sampling port and a temperature thermocouple probe. The arrangement of the flue gas sampling port and the temperature thermocouple probe realizes the coupling design of uniform flue gas sampling and grid method temperature measurement, which can accurately obtain the flue gas temperature and composition information at different locations in the flue section.

[0026] (2) Flue gas analysis device: A mixing chamber is set up. The flue gas from each branch pipe is sampled at multiple points and mixed in the mixing chamber to analyze the flue gas composition and obtain the overall flue gas composition data of the denitrification inlet. At the same time, two mixing chambers are designed in parallel. One is used to measure the flue gas parameters after mixing, and the other can be used with a shut-off valve to measure the flue gas composition at a certain point or in a certain area when necessary, so as to provide more accurate data for the optimization of ammonia injection in the denitrification system.

[0027] Optionally, in one embodiment of this application, the denitrification inlet measurement module 100 further includes a sampling pipeline, which includes a flow regulating valve and a branch pipe. The flow regulating valve is used to adjust the flue gas flow at the denitrification inlet of the coal-fired unit or close the branch pipe according to the target measurement requirements. The branch pipe is configured in a dual-path way, which is used to perform single-point flue gas composition analysis on the second branch according to actual needs when the first branch meets the preset fault conditions, so as to obtain the oxygen field distribution.

[0028] It is understood that the flow regulating valve in the embodiments of this application is installed in the sampling pipeline to precisely regulate the flow rate of flue gas entering the analysis system.

[0029] One embodiment of this application may include a sampling pipeline design: before connecting the branch pipes of each measuring bracket to the header, a flow regulating valve is installed. This flow regulating valve has a shut-off function, which can adjust the flue gas flow or close a branch according to measurement requirements. The branch pipes adopt a dual-path arrangement, which can ensure the reliability of the measurement system. When one path fails, the other path can still operate normally. The other path is designed to enable individual measurement at each measuring point and can also serve as a backup. This embodiment of the application has sampling design advantages: the coupled design of flue gas sampling and flue gas temperature sampling, as well as the dual-path arrangement of branch pipes and the setting of flow regulating valves, improve the reliability and flexibility of the measurement system while ensuring measurement accuracy, reducing wear on measuring components, and extending the service life of the equipment.

[0030] The air preheater outlet measurement module 200 is used to measure the temperature field at the outlet flue section of the air preheater by arranging multiple measurement brackets on the brackets and using pre-set temperature thermocouple probes on the brackets. It also uses pre-set flue gas sampling ports on the brackets to extract flue gas and measure the oxygen field distribution at the outlet flue section through a mixing header. Based on the temperature field and oxygen field distribution, the module obtains the temperature field data and oxygen field data at the outlet flue section.

[0031] In actual implementation, the embodiments of this application may include: (1) Temperature field and oxygen measurement structure: At the air preheater outlet flue section (dimensions are 4m×6m), multiple measuring supports are arranged according to the Chebyshev grid method, such as 6×9 measuring supports. The support material is wear-resistant steel. Each support is equipped with one temperature thermocouple probe and one oxygen sensor. The temperature field at the outlet flue section is measured by using the temperature thermocouple probes pre-set on multiple measuring supports, and flue gas is extracted by using the flue gas sampling ports pre-set on multiple measuring supports. The oxygen value at the outlet flue section is measured through the mixing header.

[0032] (2) Data transmission and processing: Temperature and oxygen data collected by the temperature thermocouple probe and oxygen sensor, as well as the opening data of the flow control valve, are transmitted to the data acquisition card via a 4-20mA signal. The data acquisition card then transmits the data to the data processing and analysis server via an industrial Ethernet network. The data collected by the temperature thermocouple probe and oxygen sensor is transmitted to the data processing and analysis module 300 for analyzing the temperature field and oxygen distribution at the air preheater outlet, and obtaining temperature and oxygen data. This application embodiment can collect temperature and oxygen data of the flue gas cross-section at the denitrification inlet and air preheater outlet in real time using a temperature thermocouple probe and an oxygen sensor; the flow regulating valve adjusts the flue gas flow of each branch pipe; the flue gas is mixed in the mixing box after multi-point sampling or single-point sampling to collect flue gas composition data, thereby innovating flue gas composition measurement. It has the functions of mixing measurement and single-point measurement, which can not only obtain the overall flue gas composition information of the flue gas cross-section, but also perform detailed analysis of specific locations, providing accurate data for the optimization of ammonia injection in the denitrification system, improving denitrification efficiency and reducing operating costs. The data processing and analysis module 300 is used to calculate the temperature at the denitrification inlet of the coal-fired power unit that meets the preset minimum point condition based on the measurement data, and to analyze the flue gas composition at the denitrification inlet of the coal-fired power unit in the mixing box to determine the distribution of nitrogen oxides at the denitrification inlet of the coal-fired power unit. Based on the temperature field data and oxygen field data obtained by the air preheater outlet measurement module, a comprehensive judgment factor is constructed, and the blockage, leakage location and degree of air preheater are determined according to the comprehensive judgment factor.

[0033] It is understood that the temperature at the denitrification inlet of the coal-fired power unit in this embodiment of the application can be the lowest temperature at the denitrification inlet of the coal-fired power unit.

[0034] Specifically, in this embodiment of the application, the data processing and analysis module 300 can be used to calculate the lowest point of the denitrification inlet temperature of the coal-fired power unit based on the measurement data. After the analysis of flue gas components such as oxygen content is uniformly extracted into a mixing box, the measurement and analysis are performed. By analyzing the flue gas components at the denitrification inlet of the coal-fired power unit in the mixing box, the distribution of nitrogen oxides at the denitrification inlet of the coal-fired power unit can be determined. A comprehensive judgment factor is constructed based on the temperature data and oxygen content data, and the blockage status, air leakage location and air leakage degree of the air preheater are determined according to the comprehensive judgment factor.

[0035] This application embodiment can transmit the collected data to the data processing and analysis module to construct a temperature field distribution model of the denitrification inlet and air preheater outlet, analyze the temperature field distribution characteristics, and obtain the lowest temperature point of the denitrification inlet; analyze the flue gas composition data and combine it with the temperature field data to obtain the NOx distribution at the denitrification inlet; construct a comprehensive judgment factor for the air preheater outlet to assess the health status of the air preheater, thereby achieving a multi-dimensional and accurate assessment of the air preheater's health status, enabling timely detection of abnormalities such as air preheater blockage and air leakage, and conducting operational adjustments and optimizations based on the assessment results to ensure the safe operation of the air preheater and reduce maintenance costs.

[0036] It should be noted that the preset minimum point condition can be set by those skilled in the art according to the actual situation, and no specific restrictions are imposed here.

[0037] Optionally, in one embodiment of this application, the data processing and analysis module 300 includes: a temperature field analysis unit, used to construct a temperature field distribution model based on temperature data, and calculate the temperature at the denitrification inlet of the coal-fired power unit that meets the preset minimum point condition based on the temperature field distribution model; a flue gas composition analysis unit, used to process the flue gas composition data and single-point analysis data after mixing in the mixing box to obtain target data, and determine the nitrogen oxide distribution at the denitrification inlet of the coal-fired power unit based on the target data and the temperature data of the temperature field; and an air preheater health status assessment unit, used to construct a comprehensive judgment factor based on the temperature and nitrogen oxide distribution that meet the preset minimum point condition, determine the abnormal state of the air preheater based on the comprehensive judgment factor, determine the blockage and leakage location of the air preheater based on the abnormal state, actual temperature and abnormal oxygen distribution area, and determine the degree of leakage based on the correspondence between the outlet temperature and oxygen content of the air preheater.

[0038] It is understood that the comprehensive judgment factor in this application embodiment is an index constructed based on the temperature and nitrogen oxide distribution at the air preheater outlet flue section.

[0039] In actual implementation, this application embodiment can utilize a data processing and analysis server and MATLAB software to process the collected data. For the denitrification inlet temperature data, a bilinear interpolation algorithm is used to construct a temperature field distribution model and calculate the minimum denitrification inlet temperature. When the minimum temperature is below 300℃ (the lower limit of denitrification operation), the system issues an alarm signal. Simultaneously, the composition data of the mixed flue gas in the mixing chamber and single-point analysis data are analyzed, combined with the temperature field data, to determine the NOx distribution at the denitrification inlet, providing a basis for ammonia injection optimization. For the air preheater outlet data, a temperature field and oxygen distribution model is constructed, and temperature distribution uniformity indicators (such as temperature standard deviation), oxygen distribution uniformity indicators (such as oxygen standard deviation), temperature deviation indicators (deviation from the design temperature), and temperature-oxygen correlation indicators (such as those obtained through correlation analysis) are calculated. A comprehensive judgment factor is obtained through weighted calculation. When the comprehensive judgment factor exceeds a preset threshold of 0.3, it is determined that the air preheater is abnormal. Combining the temperature field and oxygen distribution, the location and extent of air preheater blockage and leakage are determined. Specifically, embodiments of this application may include: (1) Temperature field analysis: Receive temperature data transmitted by the measurement modules of the denitrification inlet and the air preheater outlet, construct a temperature field distribution model based on the Chebyshev grid method measurement data, obtain the lowest temperature point of the denitrification inlet through model calculation, and determine whether it meets the lower limit requirements of denitrification operation; analyze the uniformity and symmetry of the temperature field distribution at the air preheater outlet, compare it with the temperature field distribution under standard conditions, and determine whether there are abnormalities such as blockage or air leakage in the air preheater. (2) Flue gas composition analysis: The flue gas composition data and single-point analysis data after mixing in the denitrification inlet mixing box are processed and combined with temperature field data to analyze the NOx distribution at the denitrification inlet, providing data support for the optimization of ammonia injection in the denitrification system. (3) Air preheater health status assessment: A comprehensive judgment factor is constructed by combining the air preheater outlet temperature field and oxygen distribution. This comprehensive judgment factor is calculated by weighting multiple parameters such as temperature distribution uniformity index, temperature deviation index, oxygen distribution uniformity index, and temperature-oxygen correlation index through a preset algorithm. The air preheater's health status, such as blockage degree, air leakage, and heat exchange efficiency, is comprehensively assessed based on the comprehensive judgment factor. The calculation method of the air preheater outlet comprehensive analysis factor K is: K=a*(Tstd / T_avg) + b*(Ostd / Oavg) + c*(ΔTmax / Tavg), where Tstd is the standard deviation of outlet temperature, Tavg is the average outlet temperature, Ostd is the standard deviation of oxygen, Oavg is the average oxygen, ΔTmax is the maximum temperature deviation (compared with the design value), and a, b, and c are weighting coefficients determined through historical data and expert experience. When the K value exceeds the preset threshold (e.g., 0.2), the air preheater is determined to be in an abnormal state. Based on the specific abnormal temperature and oxygen distribution areas, the possible blockage or air leakage locations are located, and suggestions for soot blowing or maintenance are given.

[0040] In addition, the relationship between air preheater outlet temperature and oxygen content can be used to determine air leakage. If the temperature in a region continues to decrease and the oxygen content in the corresponding region increases, it is predicted that the cold end air leakage rate in that region will increase. If the exhaust gas temperature in that region continues to increase and the oxygen content in the corresponding region increases, it is predicted that the hot end air leakage in that region will increase. If the exhaust gas temperature in that region increases under the same operating conditions and the oxygen content does not change significantly, it is predicted that the air preheater blockage in that region will worsen, based on the change in air preheater resistance.

[0041] This application embodiment can perform air preheater health management: by combining the oxygen content and flue gas temperature distribution at the air preheater outlet, a comprehensive judgment factor is proposed, which realizes a multi-dimensional and accurate assessment of the health status of the air preheater. It can promptly detect abnormalities such as air preheater blockage and air leakage, and adjust and optimize the operation based on the assessment results, ensuring the safe operation of the air preheater and reducing maintenance costs.

[0042] The control execution module 400 is used to adjust the operating parameters of the denitrification system according to the temperature that meets the preset minimum point condition in order to optimize the operation of the denitrification system, and to adjust the operating parameters of the air preheater according to the blockage, leakage location and degree of the air preheater in order to optimize the operation of the air preheater.

[0043] It is understood that the denitrification system in the embodiments of this application can be a general term for a series of technologies and equipment used to remove nitrogen oxides (NOx) generated during the combustion process of coal-fired power units, etc.

[0044] In this embodiment, the control execution module 400 performs control based on data processing and analysis results. When the denitrification inlet temperature is detected to be too low, it sends a command to the DCS (Distributed Control System) to increase the secondary air volume of the burner, raise the furnace temperature, or adjust the ammonia injection volume to optimize the operation of the denitrification system. When it is determined that there is a risk of blockage in the air preheater, the control execution module adjusts the soot blowing frequency and time of the air preheater; when it is detected that the air preheater leakage rate is high, it sends a command to the air preheater sealing sector plate adjustment system based on the air preheater outlet flue gas temperature and oxygen content data to optimize the sector plate position and reduce the leakage rate. By implementing the measurement system and method of this application on the 600MW coal-fired unit, the denitrification efficiency of the denitrification system under wide load conditions was improved by 8%-12%, and ammonia slip was reduced by 30%-40%; the air preheater leakage rate was reduced by 5-8 percentage points, and blockage was significantly reduced, resulting in a significant improvement in the safety and economy of the unit operation. This application provides a basis for sealing adjustment: by using the air preheater outlet flue gas temperature and oxygen content data to guide the adjustment of the air preheater sealing sector plate, effective data support is provided for controlling the leakage rate of the sector plate, which can optimize the air preheater sealing performance, reduce the leakage rate, and improve the unit operating efficiency.

[0045] Specifically, embodiments of this application may include: (1) Denitrification system control: Based on the denitrification inlet temperature field data provided by the data processing and analysis module, when the lowest point of the denitrification inlet temperature is detected to be close to or below the denitrification operating limit, the control execution module issues an instruction to adjust the operation of the wide-load denitrification system, such as adjusting the ammonia injection amount and optimizing the combustion conditions, to ensure that there is no low point in the denitrification inlet flue gas temperature, improve the denitrification efficiency, and reduce ammonia escape. (2) Air preheater optimization and adjustment: Based on the air preheater outlet temperature field, oxygen distribution and comprehensive judgment factors, the control execution module issues instructions to adjust the operating parameters of the air preheater, such as adjusting the comprehensive cold end temperature to prevent air preheater blockage; at the same time, combined with the air preheater outlet flue gas temperature and oxygen data, it provides a basis for the adjustment of the air preheater sealing sector plate, optimizes the sector plate position and reduces the air preheater leakage rate.

[0046] This application embodiment can control and adjust the denitrification system and air preheater based on the results of the data processing and analysis module. For the denitrification system, it ensures that the inlet flue gas temperature meets the operating requirements and optimizes the ammonia injection rate. For the air preheater, it adjusts the operating parameters and the position of the fan-shaped plate to ensure the safe and efficient operation of the air preheater. This application embodiment can optimize denitrification control: by monitoring the inlet flue gas temperature field in real time, it can more comprehensively control the wide-load denitrification system, and adjust the operating parameters of the denitrification system in a timely manner according to the temperature field conditions to ensure that the inlet flue gas temperature meets the requirements, thereby improving the adaptability and stability of the denitrification system.

[0047] Specifically, it can be combined with Figure 2 As shown, the working principle of the denitrification inlet and air preheater outlet parameter control system of the coal-fired unit in this application embodiment is described in detail with a specific embodiment.

[0048] like Figure 2 As shown in the schematic diagram of the arrangement of the measuring support in the flue gas duct in this embodiment of the application, the system includes: 1-Selective Catalytic Reduction (SCR) denitrification system, 2-Air preheater, 3-Measuring support, 4-Temperature bus, 5-Temperature acquisition box, 6-Mixing header I, 7-Mixing header II, 8-Flue gas analyzer I, 9-Flue gas analyzer II, 10-Shut-off valve, 11-Flue gas sampling port, 12-Temperature thermocouple probe, and 13-Flow regulating valve. A schematic diagram of the AA / BB cross-section flue gas parameter analysis system layout is shown below. Figure 3 As shown in the diagram, the internal structure of the measuring bracket is as follows: Figure 4 As shown.

[0049] The denitrification inlet and air preheater outlet parameter control system for coal-fired power units proposed in this application can achieve high-precision measurement of the temperature field and flue gas composition at the denitrification inlet and air preheater outlet through innovative measurement systems and methods. This provides reliable data support for wide-load denitrification control and air preheater health management, ensuring the safe, efficient, and environmentally friendly operation of coal-fired power units under the new power system. This solves the problems in related technologies, such as insufficient temperature measurement points at the denitrification inlet and air preheater outlet of coal-fired power units, incomplete temperature field measurement, single flue gas composition measurement, inability to effectively achieve precise control of denitrification under wide loads, and difficulty in accurately assessing the health status of the air preheater and optimizing its adjustment.

[0050] Next, referring to the accompanying drawings, a method for controlling the denitrification inlet and air preheater outlet parameters of a coal-fired power unit according to an embodiment of this application is described.

[0051] Figure 5 This is a flowchart of a method for controlling the parameters of the denitrification inlet and air preheater outlet of a coal-fired power unit according to an embodiment of this application.

[0052] like Figure 5 As shown, the control methods for the denitrification inlet and air preheater outlet parameters of this coal-fired unit include: In step S501, after arranging multiple measuring supports at the flue section of the denitrification inlet of the coal-fired power unit, flue gas is uniformly sampled at the flue gas sampling ports pre-set on the multiple measuring supports, and temperature field measurement coupling is performed on the temperature thermocouple probes pre-set on the multiple measuring supports to generate measurement data of the denitrification inlet of the coal-fired power unit.

[0053] In step S502, after arranging multiple measuring supports at the outlet flue section of the air preheater, the temperature field at the outlet flue section is measured using temperature thermocouple probes pre-set on the multiple measuring supports, and flue gas is extracted using flue gas sampling ports pre-set on the multiple measuring supports. The oxygen field distribution at the outlet flue section is measured through the mixing header, so as to obtain the temperature field data and oxygen field data at the outlet flue section based on the temperature field and oxygen field distribution.

[0054] In step S503, the temperature at which the denitrification inlet of the coal-fired power unit meets the preset minimum point condition is calculated based on the measurement data. The flue gas composition at the denitrification inlet of the coal-fired power unit is analyzed in the mixing box to determine the distribution of nitrogen oxides at the denitrification inlet of the coal-fired power unit. A comprehensive judgment factor is constructed based on the temperature field data and oxygen field data obtained by the air preheater outlet measurement module. The blockage status, leakage location and leakage degree of the air preheater are determined according to the comprehensive judgment factor.

[0055] In step S504, the operating parameters of the denitrification system are adjusted according to the temperature that meets the preset minimum point condition to optimize the operation of the denitrification system, and the operating parameters of the air preheater are adjusted according to the blockage, leakage location and degree of the air preheater to optimize the operation of the air preheater.

[0056] Optionally, in one embodiment of this application, flue gas is uniformly sampled at pre-set flue gas sampling ports on multiple measuring supports, and temperature measurement coupling is performed on at least one pre-set temperature thermocouple probe on multiple measuring supports to generate measurement data of the denitrification inlet of the coal-fired power unit. This includes: acquiring flue gas temperature and flue gas composition information at the flue section of the denitrification inlet of the coal-fired power unit; after setting up a mixing box, the flue gas from each branch pipe is sampled at multiple points and mixed in the mixing box to perform flue gas composition analysis on the flue gas temperature and flue gas composition information, determine the flue gas composition data of the denitrification inlet of the coal-fired power unit, and generate measurement data of the denitrification inlet based on the flue gas composition data.

[0057] Optionally, in one embodiment of this application, uniform sampling of flue gas is performed on multiple pre-set flue gas sampling ports on multiple measuring supports, which further includes: when the first branch meets the preset fault conditions, the second branch performs single-point flue gas composition analysis according to actual needs to obtain the oxygen field distribution.

[0058] Optionally, in one embodiment of this application, the temperature at which the denitrification inlet of the coal-fired power unit meets the preset minimum point condition is calculated based on measurement data, and the flue gas composition at the denitrification inlet of the coal-fired power unit is analyzed in the mixing chamber to determine the distribution of nitrogen oxides at the denitrification inlet of the coal-fired power unit. A comprehensive judgment factor is constructed based on the temperature field data and oxygen field data obtained from the air preheater outlet measurement module, and the blockage status, leakage location, and leakage degree of the air preheater are determined according to the comprehensive judgment factor. This includes: constructing a temperature field distribution model based on the temperature field data, and calculating the temperature at which the denitrification inlet of the coal-fired power unit meets the preset minimum point condition based on the temperature field distribution model. The system sets a minimum temperature condition; it processes the flue gas composition data and single-point analysis data after mixing in the mixing chamber to obtain target data, and determines the nitrogen oxide distribution at the denitrification inlet of the coal-fired unit based on the target data and temperature field data; it constructs a comprehensive judgment factor based on the temperature and nitrogen oxide distribution that meet the minimum temperature condition, determines the abnormal state of the air preheater based on the comprehensive judgment factor, and determines the blockage and leakage location of the air preheater based on the abnormal state, actual temperature and abnormal oxygen distribution area, and determines the degree of leakage based on the correspondence between the outlet temperature and oxygen content of the air preheater.

[0059] It should be noted that the explanation of the aforementioned embodiment of the control system for the denitrification inlet and air preheater outlet parameters of a coal-fired unit also applies to the control method for the denitrification inlet and air preheater outlet parameters of the coal-fired unit in this embodiment, and will not be repeated here.

[0060] The method for controlling the parameters of the denitrification inlet and air preheater outlet of a coal-fired power unit, as proposed in the embodiments of this application, can achieve high-precision measurement of the temperature field and flue gas composition at the denitrification inlet and air preheater outlet through an innovative measurement system and method. This provides reliable data support for wide-load denitrification control and air preheater health management, ensuring the safe, efficient, and environmentally friendly operation of the coal-fired power unit under the new power system. This solves the problems in related technologies, such as insufficient temperature measurement points at the denitrification inlet and air preheater outlet of coal-fired power units, incomplete temperature field measurement, single flue gas composition measurement, inability to effectively achieve precise control of denitrification under wide loads, and difficulty in accurately assessing the health status of the air preheater and optimizing its adjustment.

[0061] Figure 6 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include: The memory 601, the processor 602, and the computer program stored on the memory 601 and capable of running on the processor 602.

[0062] When the processor 602 executes the program, it implements the method for controlling the parameters of the denitrification inlet and the air preheater outlet of the coal-fired unit provided in the above embodiments.

[0063] Furthermore, electronic devices also include: Communication interface 603 is used for communication between memory 601 and processor 602.

[0064] The memory 601 is used to store computer programs that can run on the processor 602.

[0065] The memory 601 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0066] If the memory 601, processor 602, and communication interface 603 are implemented independently, then the communication interface 603, memory 601, and processor 602 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 6 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0067] Optionally, in a specific implementation, if the memory 601, processor 602, and communication interface 603 are integrated on a single chip, then the memory 601, processor 602, and communication interface 603 can communicate with each other through an internal interface.

[0068] The processor 602 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0069] This embodiment also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for controlling the parameters of the denitrification inlet and air preheater outlet of a coal-fired power unit.

[0070] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do 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 one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0071] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0072] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0073] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0074] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0075] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0076] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0077] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A control system for denitrification inlet and air preheater outlet parameters of a coal-fired power unit, characterized in that, include: The denitrification inlet measurement module is used to uniformly sample flue gas at the flue gas sampling ports pre-set on the multiple measurement supports after arranging multiple measurement supports at the flue gas cross-section of the denitrification inlet of the coal-fired unit, and to perform temperature field measurement coupling with the temperature thermocouple probes pre-set on the multiple measurement supports to generate measurement data of the denitrification inlet of the coal-fired unit. An air preheater outlet measurement module is used to measure the temperature field at the outlet flue section of the air preheater by arranging the multiple measurement brackets on the multiple measurement brackets and using temperature thermocouple probes pre-set on the multiple measurement brackets to measure the flue gas, and to extract flue gas by using flue gas sampling ports pre-set on the multiple measurement brackets, and to measure the oxygen field distribution at the outlet flue section through a mixing header, so as to obtain temperature field data and oxygen field data at the outlet flue section based on the temperature field and the oxygen field distribution; The data processing and analysis module is used to calculate the temperature at which the denitrification inlet of the coal-fired power unit meets the preset minimum point condition based on the measurement data, and to analyze the flue gas composition at the denitrification inlet of the coal-fired power unit in the mixing box to determine the distribution of nitrogen oxides at the denitrification inlet of the coal-fired power unit. Based on the temperature field data and oxygen field data obtained by the air preheater outlet measurement module, a comprehensive judgment factor is constructed, and the blockage status, air leakage location and air leakage degree of the air preheater are determined according to the comprehensive judgment factor. The control execution module is used to adjust the operating parameters of the denitrification system according to the temperature that meets the preset minimum point condition in order to optimize the operation of the denitrification system, and to adjust the operating parameters of the air preheater according to the blockage, leakage location and degree of the air preheater in order to optimize the operation of the air preheater.

2. The control system for denitrification inlet and air preheater outlet parameters of a coal-fired power unit according to claim 1, characterized in that, The denitrification inlet measurement module includes: Temperature field and flue gas composition measurement unit, used to acquire flue gas temperature and flue gas composition information at the flue gas cross section of the denitrification inlet of the coal-fired unit; The flue gas analysis unit is installed after the mixing box to sample the flue gas from each branch pipe at multiple points and mix them in the mixing box to analyze the flue gas temperature and composition information, determine the flue gas composition data at the denitrification inlet of the coal-fired unit, and generate measurement data for the denitrification inlet based on the flue gas composition data.

3. The control system for denitrification inlet and air preheater outlet parameters of a coal-fired power unit according to claim 2, characterized in that, The denitrification inlet measurement module also includes: The sampling pipeline includes a flow regulating valve and a branch pipe. The flow regulating valve is used to adjust the flue gas flow at the denitrification inlet of the coal-fired unit or close the branch pipe according to the target measurement requirements. The branch pipe is configured in a dual-path way, so that if the first branch meets the preset fault conditions, the second branch can perform single-point flue gas composition analysis according to actual needs to obtain the oxygen field distribution.

4. The control system for denitrification inlet and air preheater outlet parameters of a coal-fired power unit according to claim 1, characterized in that, The data processing and analysis module includes: The temperature field analysis unit is used to construct a temperature field distribution model based on the temperature data, and to calculate the temperature at the denitrification inlet of the coal-fired unit that meets the preset minimum point condition based on the temperature field distribution model. The flue gas composition analysis unit is used to process the flue gas composition data and single-point analysis data after mixing in the mixing box to obtain target data, and based on the target data and the temperature data of the temperature field, to determine the distribution of nitrogen oxides at the denitrification inlet of the coal-fired unit. An air preheater health status assessment unit is used to construct a comprehensive judgment factor based on the temperature that meets the preset minimum point condition and the distribution of nitrogen oxides, determine the abnormal state of the air preheater based on the comprehensive judgment factor, determine the blockage and leakage location of the air preheater based on the abnormal state, actual temperature and abnormal oxygen distribution area, and determine the degree of leakage based on the correspondence between the outlet temperature and oxygen content of the air preheater.

5. A method for controlling the parameters of the denitrification inlet and air preheater outlet of a coal-fired power unit, characterized in that, Includes the following steps: After arranging multiple measuring supports at the flue section of the denitrification inlet of the coal-fired power unit, flue gas is uniformly sampled at the flue gas sampling ports pre-set on the multiple measuring supports, and temperature field measurement coupling is performed on the temperature thermocouple probes pre-set on the multiple measuring supports to generate measurement data of the denitrification inlet of the coal-fired power unit. After arranging the multiple measuring brackets at the outlet flue section of the air preheater, the temperature field at the outlet flue section is measured using temperature thermocouple probes pre-set on the multiple measuring brackets, and flue gas is extracted using flue gas sampling ports pre-set on the multiple measuring brackets. The oxygen field distribution at the outlet flue section is measured through a mixing header, so as to obtain temperature field data and oxygen field data at the outlet flue section based on the temperature field and the oxygen field distribution. Based on the measurement data, the temperature at which the denitrification inlet of the coal-fired power unit meets the preset minimum point condition is calculated. The flue gas composition at the denitrification inlet of the coal-fired power unit is analyzed in the mixing box to determine the distribution of nitrogen oxides at the denitrification inlet of the coal-fired power unit. A comprehensive judgment factor is constructed based on the temperature field data and oxygen field data obtained by the air preheater outlet measurement module. The blockage status, air leakage location and air leakage degree of the air preheater are determined according to the comprehensive judgment factor. The operating parameters of the denitrification system are adjusted according to the temperature that meets the preset minimum point condition to optimize the operation of the denitrification system. The operating parameters of the air preheater are also adjusted according to the blockage, leakage location and degree of the air preheater to optimize the operation of the air preheater.

6. The method for controlling the parameters of the denitrification inlet and air preheater outlet of a coal-fired power unit according to claim 5, characterized in that, The process of uniformly sampling flue gas through pre-set flue gas sampling ports on the multiple measuring supports, and coupling temperature field measurements with pre-set temperature thermocouple probes on the multiple measuring supports to generate measurement data for the denitrification inlet of the coal-fired unit, includes: Obtain flue gas temperature and composition information at the flue gas cross-section of the denitrification inlet of the coal-fired unit; After setting up the mixing box, the flue gas from each branch pipe is sampled at multiple points and mixed in the mixing box to analyze the flue gas temperature and composition information, determine the flue gas composition data at the denitrification inlet of the coal-fired unit, and generate the measurement data of the denitrification inlet based on the flue gas composition data.

7. The method for controlling the parameters of the denitrification inlet and air preheater outlet of a coal-fired power unit according to claim 6, characterized in that, The step of uniformly sampling flue gas through the pre-set flue gas sampling ports on the plurality of measuring supports further includes: When the first branch meets the preset fault conditions, the second branch performs single-point flue gas composition analysis according to actual needs to obtain the oxygen field distribution.

8. The method for controlling the parameters of the denitrification inlet and air preheater outlet of a coal-fired power unit according to claim 6, characterized in that, The process involves calculating the temperature at the denitrification inlet of the coal-fired power unit that meets the preset minimum point condition based on the measured data, analyzing the flue gas composition at the denitrification inlet of the coal-fired power unit in the mixing chamber to determine the distribution of nitrogen oxides at the denitrification inlet of the coal-fired power unit, constructing a comprehensive judgment factor based on the temperature field data and oxygen field data obtained from the air preheater outlet measurement module, and determining the blockage status, leakage location, and leakage degree of the air preheater based on the comprehensive judgment factor, including: A temperature field distribution model is constructed based on the temperature field data, and the temperature at the denitrification inlet of the coal-fired unit that meets the preset minimum point condition is calculated based on the temperature field distribution model. The flue gas composition data and single-point analysis data after mixing in the mixing box are processed to obtain target data. Based on the target data and the temperature field data, the distribution of nitrogen oxides at the denitrification inlet of the coal-fired unit is determined. The comprehensive judgment factor is constructed based on the temperature that meets the preset minimum point condition and the distribution of nitrogen oxides. The abnormal state of the air preheater is determined based on the comprehensive judgment factor. Based on the abnormal state, the actual temperature and the abnormal oxygen distribution area, the blockage and leakage location of the air preheater are determined. The degree of leakage is determined based on the correspondence between the outlet temperature and oxygen content of the air preheater.

9. An electronic device, characterized in that, include: The memory, the processor, and the computer program stored in the memory and executable on the processor, the processor executing the program to implement the method for controlling the denitrification inlet and air preheater outlet parameters of a coal-fired unit as described in any one of claims 7-8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the method for controlling the denitrification inlet and air preheater outlet parameters of a coal-fired unit as described in any one of claims 7-8.

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