Combustion optimization control system for low load of unit

Abstract

The invention provides a low-load combustion optimization control system for a unit, and the system comprises a sensing network module which collects key parameters of the unit in a combustion process; the data preprocessing module is used for preprocessing the collected key parameters; the index analysis module is used for analyzing the energy balance deviation degree, chemical balance and combustion uniformity evaluation indexes of the current unit based on the preprocessed key parameters; the control strategy execution module is used for carrying out threshold value judgment on the result of each index and correspondingly executing preset energy balance, chemical balance and combustion uniformity strategies; the feedback regulation module is used for acquiring the executed feedback signal and performing new index analysis and cyclic regulation to form a closed-loop feedback mechanism; energy balance, chemical balance and combustion uniformity in the combustion process are analyzed and controlled, so that combustion stability and combustion efficiency are improved, pollutant emission is reduced, the service life of equipment is prolonged, and meanwhile, the adaptability of a unit to a power grid is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of thermal power generation, and in particular to a combustion optimization control system for a low-load unit. Background Art

[0002] As the global energy landscape continues to evolve, thermal power generation, as an important pillar of power supply, has long played a key role in ensuring stable electricity consumption in society. With the continuous advancement of science and technology and the rapid development of social economy, the demand for electricity has continued to grow, and at the same time, more stringent requirements have been put forward for the stability, efficiency and environmental protection of power supply. Early thermal power generation technology mainly focused on meeting basic power needs. The units were relatively extensive in design and operation, and the control of the combustion process mainly relied on experience and relatively simple monitoring methods. As time goes by, the complexity of the power system continues to increase, especially after renewable energy such as wind power and solar energy are connected to the power grid on a large scale, thermal power units are facing unprecedented challenges.

[0003] On the one hand, the intermittent and volatile characteristics of renewable energy affect the operational stability of the power grid. In order to ensure the safe and stable operation of the power grid, thermal power units need to have stronger flexibility and peak-shaving capabilities, that is, they can operate efficiently under different load conditions, especially under low-load conditions, and need to maintain good combustion stability and efficiency to adapt to the dynamic changes in the power grid load. However, traditional thermal power units have exposed many problems when operating at low loads. For example, unstable combustion leads to flame pulsation and flameout, which not only affects power generation efficiency, but may also cause safety accidents. Incomplete combustion increases pollutant emissions, putting greater pressure on the environment. At the same time, long-term operation of equipment at low loads will accelerate wear, shorten equipment life, and increase maintenance costs.

[0004] On the other hand, with the increasing awareness of environmental protection, the pollutant emission standards for thermal power units are constantly tightened; traditional combustion control methods are difficult to effectively control the emission of pollutants such as nitrogen oxides, sulfur dioxide, and particulate matter while meeting the requirements of low-load operation; this urgently requires a more advanced and intelligent combustion optimization control system that can accurately control the combustion process under low-load conditions to achieve efficient and clean combustion;

[0005] Therefore, there is an urgent need in the art for a combustion optimization control system for low-load units to solve the above-mentioned problems. Summary of the invention

[0006] The present invention provides a combustion optimization control system for low-load units, aiming to solve the above-mentioned technical problems. By analyzing and controlling the energy balance, chemical balance and combustion uniformity in the combustion process, the combustion stability and efficiency are improved, pollutant emissions are reduced, the service life of the equipment is extended, and the adaptability of the unit to the power grid is enhanced.

[0007] The present invention provides a combustion optimization control system for a low-load unit, comprising:

[0008] A sensor network module, which is used to collect key parameters of the combustion process of the unit when it is running at low load; the key parameters include combustion chamber operating parameters, fan inlet operating parameters and flue operating parameters;

[0009] A data preprocessing module, which is connected to the sensor network module and is used to preprocess the collected key parameters, wherein the preprocessing process includes filtering and calibration processing;

[0010] An index analysis module, which is connected to the data preprocessing module, establishes an energy balance model, a chemical balance model and a combustion uniformity analysis model based on the key parameters after preprocessing, and determines the energy balance deviation degree index, chemical balance index and combustion uniformity evaluation index of the current unit through model analysis;

[0011] A control strategy execution module, which is connected to the index analysis module and is used to perform threshold determination on the results of each index, and execute preset energy balance strategy, chemical balance strategy and combustion uniformity strategy based on the determination results to optimize the combustion process;

[0012] The feedback adjustment module is connected to the index analysis module and the control strategy execution module, and is used to obtain the feedback signal after execution, and perform a new index analysis and cyclic adjustment to form a closed-loop feedback mechanism.

[0013] According to a combustion optimization control system for a low-load unit provided by the present invention, the sensor network module comprises:

[0014] A combustion chamber sensor unit is installed in each combustion chamber and is used to obtain the type of fuel involved in the combustion, the flow rate of each type of fuel at the initial moment and the total flow rate at the current moment, the surface area of ​​the inner wall of the combustion chamber, the temperature of the inner wall, the carbon dioxide component concentration at the initial moment, the unburned hydrocarbon component concentration at the initial moment, the carbon dioxide component concentration at the current moment, and the unburned hydrocarbon component concentration at the current moment; a number of measuring points are pre-set in each combustion chamber to monitor the temperature and pressure of each measuring point in real time;

[0015] A fan inlet sensor unit is mounted at the fan inlet and is used to obtain the air temperature at the fan inlet;

[0016] The flue sensor unit is installed in the flue and is used to obtain the types of main combustion products in the flue, the concentrations and specific heat capacities of various products, flue gas temperature, exhaust density and exhaust flow rate.

[0017] According to a combustion optimization control system for a low-load unit provided by the present invention, the data preprocessing module comprises:

[0018] The data acquisition unit is used to receive various types of raw data collected by each sensor unit and store them according to data type and source to ensure the integrity and traceability of the data;

[0019] A filtering unit, connected to the data acquisition unit, uses a median filtering method or a mean filtering method to process the classified and stored data;

[0020] The calibration unit is connected to the data acquisition unit and calibrates the data collected by each sensor unit according to preset calibration parameters and data of a standard measuring device.

[0021] According to a combustion optimization control system for a low-load unit provided by the present invention, the index analysis module includes:

[0022] An energy balance model building unit, which is connected to the data acquisition unit and is used to build an energy balance model, analyze the heat generated by combustion, the heat taken away by combustion products, and the heat loss of the combustion chamber wall, and calculate the energy balance deviation index by solving the model to evaluate the energy utilization in the combustion process and the degree of deviation from the ideal equilibrium state;

[0023] A chemical equilibrium model building unit, which is connected to the data acquisition unit and is used to build a chemical equilibrium model, analyze the relationship between the actual measured concentration and the theoretical concentration based on the combustion reaction of the fuel, and calculate the chemical equilibrium index, so as to judge the degree and direction of the combustion reaction and whether there is incomplete combustion;

[0024] The combustion uniformity analysis model building unit is connected to the data acquisition unit and is used to build a combustion uniformity analysis model. By calculating the deviation between the temperature and pressure of each measuring point and the average temperature and pressure of the combustion chamber, the uniformity of combustion in the combustion chamber is comprehensively evaluated to obtain a combustion uniformity evaluation index, which is used to reflect the spatial uniformity of the combustion process.

[0025] According to a combustion optimization control system for a low-load unit provided by the present invention, the energy balance model is:

[0026] Q in =m f *Q LHV，tot *η comb

[0027]

[0028] Q out =Σm x *C p，x *(T flue -T air )

[0029] m x =C x * flue *V flue

[0030]

[0031]

[0032] Among them, E is the balance deviation index; Q in The heat released by fuel combustion, m f is the total fuel flow at the current moment, Q LHV，tot is the lower calorific value of the fuel, η comb is the combustion efficiency, combustion efficiency η comb Theoretical values ​​are used; k is the fuel type index, d is the total number of fuel types, m f，k is the initial flow rate of the kth fuel, Q LHV，k is the lower calorific value of the kth fuel;

[0033] Q out is the heat carried away by the combustion products, m x is the mass flow rate of combustion product x, C p，x is the specific heat capacity of the combustion product x, T flue is the exhaust gas temperature, T air is the air temperature; C x is the concentration of the combustion product x, ρ flue is the smoke density of the combustion product x, V flue is the exhaust flow rate of combustion product x;

[0034] Q loss is the heat loss from the combustion chamber wall, A w is the surface area of ​​the inner wall of the combustion chamber, T w is the inner wall temperature, T amb is the ambient temperature, n is the normal direction of the wall, is the normal temperature gradient of the wall, k wis the thermal conductivity of the combustion chamber wall material, h is the convective heat transfer coefficient, which represents the amount of heat transferred when the temperature difference between the fluid and the solid surface is one unit per unit time and per unit area during the convective heat transfer process. It is used to reflect the efficiency of heat transfer between the fluid and the solid wall, and its value is determined based on experiments.

[0035] According to a combustion optimization control system for a low-load unit provided by the present invention, the chemical equilibrium model is:

[0036]

[0037] Among them, ξ is the chemical balance index; [CO2] is the concentration of carbon dioxide at the current moment, [CO2]0 is the concentration of carbon dioxide at the initial moment, [C x H y ]0 is the concentration of unburned hydrocarbon components at the initial moment, [C x H y ] is the concentration of unburned hydrocarbon components at the current moment; s is the coefficient determined by the stoichiometric number in the chemical reaction process, representing the quantitative correspondence between the fuel and the combustion products in the chemical reaction.

[0038] According to a combustion optimization control system for a low-load unit provided by the present invention, the combustion uniformity analysis model is:

[0039]

[0040]

[0041]

[0042] Among them, U is the combustion uniformity evaluation index; is the average temperature of the combustion chamber, is the average pressure of the combustion chamber; N is the number of burners, M is the number of measuring points for each burner, T is j，i is the temperature of the jth burner and the ith measurement, P j，i is the pressure of the jth burner and the i-th measurement.

[0043] According to a combustion optimization control system for a low-load unit provided by the present invention, the control strategy execution module includes:

[0044] An energy balance strategy execution unit is connected to the energy balance model establishment unit, and when the energy balance deviation index exceeds a preset energy balance threshold, a corresponding strategy is executed; if the energy input is less than the sum of the energy output and the loss, the fuel flow rate is increased according to a preset basic ratio, and the ratio value is determined according to the energy response characteristics of the unit and the current operating parameters; at the same time, according to the increase in the fuel flow rate, the air flow rate is adjusted accordingly according to the stoichiometric relationship to maintain a suitable air-fuel ratio; if the energy input is greater than the sum of the energy output and the loss, the exhaust temperature and the wall heat loss are checked, and if the exhaust temperature is too high, the air flow rate is appropriately increased to enhance the cooling effect; if the wall heat loss is abnormal, the insulation condition of the combustion chamber wall is checked or the operating parameters are adjusted to reduce the wall temperature gradient;

[0045] A chemical balance strategy execution unit is connected to the chemical balance model establishment unit. When the chemical balance index is lower than a preset chemical balance threshold, if the concentration of unburned hydrocarbons in the combustion chamber is too high, indicating that the fuel is not fully burned, the air flow rate is increased, and the flame shape and position of the burner are adjusted, including changing the burner nozzle angle or internal structure, so that the fuel and air are better mixed; if the oxygen concentration is too high, the air flow rate is reduced according to a preset basic ratio while ensuring stable combustion, and the uniformity and stability of the fuel supply system are checked to avoid local fuel being too thin, resulting in reduced combustion efficiency;

[0046] A combustion uniformity strategy execution unit is connected to the combustion uniformity analysis model establishment unit. When the combustion uniformity evaluation index is lower than a preset combustion uniformity threshold, for areas where the temperature is higher than the average temperature of the combustion chamber, the fuel flow of the burner in this area is reduced, and the reduction ratio is determined according to the size of the temperature deviation; at the same time, the air flow is fine-tuned to maintain a suitable air-fuel ratio; for areas where the temperature is lower than the average temperature, the fuel flow is increased and the air flow is adjusted accordingly; in addition, personnel are notified to check whether the burner has blockage or wear failure that affects the uniform distribution of fuel and air.

[0047] According to a combustion optimization control system for a low-load unit provided by the present invention, the feedback adjustment module comprises:

[0048] A feedback signal acquisition unit is used to receive in real time new data collected by each sensor unit after the control strategy is executed, and form a feedback signal set to reflect the change of the combustion state after the control strategy is executed;

[0049] A cyclic adjustment unit is connected to the feedback signal acquisition unit and the index analysis module, and is used to transmit the feedback signal set to the index analysis module to start a new index analysis process; based on the new index result, the control strategy execution module performs threshold judgment and strategy execution again, and the cycle is repeated to achieve dynamic optimization of the combustion process; during the cycle, the control parameters are continuously adjusted to adapt to changes in the unit operation process to ensure that the unit always maintains a combustion state close to the optimal state.

[0050] A combustion optimization control system for low-load units provided according to the present invention also includes a visualization module; the visualization module is used to display the analysis results of various indicators, the strategy execution process and the feedback signal set to the management personnel.

[0051] Compared with the prior art, the beneficial effects of this application are:

[0052] This application collects comprehensive key parameters through the sensor network module, including combustion chamber, fan inlet and flue operating parameters, such as fuel type, flow rate, combustion chamber inner wall related parameters, concentrations of various gas components, temperature and pressure at the measuring point, fan inlet air temperature, combustion product related information in the flue, etc.; Based on these detailed data, the index analysis module can establish accurate energy balance, chemical balance and combustion uniformity analysis models, and then accurately evaluate the combustion state and determine the corresponding indicators; the control strategy execution module makes accurate threshold judgments based on these indicators, and executes targeted control strategies to achieve refined control and optimization of the combustion process;

[0053] This application uses a combustion uniformity analysis model and a burner adjustment strategy to effectively solve the problem of unstable combustion under low-load conditions; uses an energy balance model and related control strategies to improve the low combustion efficiency during low-load operation; and provides an effective solution to the problem of increased pollutant emissions caused by insufficient low-load combustion based on a chemical balance model and a chemical balance strategy.

[0054] This application avoids damage to equipment caused by abnormal conditions such as unstable combustion and local overheating by real-time monitoring and optimization of the combustion process; at the same time, it enables the unit to maintain efficient, stable and clean combustion when operating at low load, and better adapt to dynamic changes in grid load.

[0055] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0056] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0058] Figure 1 It is a structural schematic diagram of a combustion optimization control system for a low-load unit provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0059] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0060] Embodiment 1:

[0061] The embodiment of the present invention provides a combustion optimization control system for a low-load unit. Figure 1 ,include:

[0062] The sensor network module is used to collect key parameters of the combustion process when the unit is running at low load; the key parameters include combustion chamber operating parameters, fan inlet operating parameters and flue operating parameters;

[0063] A data preprocessing module, which is connected to the sensor network module and is used to preprocess the collected key parameters. The preprocessing process includes filtering and calibration processing;

[0064] The index analysis module is connected with the data preprocessing module, and establishes an energy balance model, a chemical balance model and a combustion uniformity analysis model based on the key parameters after preprocessing, and determines the energy balance deviation index, chemical balance index and combustion uniformity evaluation index of the current unit through model analysis;

[0065] A control strategy execution module, which is connected to the index analysis module, is used to determine the threshold of the results of each index, and execute the preset energy balance strategy, chemical balance strategy and combustion uniformity strategy based on the judgment results to optimize the combustion process;

[0066] The feedback adjustment module is connected with the index analysis module and the control strategy execution module to obtain the feedback signal after execution and perform a new index analysis and cyclic adjustment to form a closed-loop feedback mechanism.

[0067] The principle and beneficial effects of this embodiment are as follows: this embodiment can significantly improve energy utilization efficiency and reduce operating costs by accurately controlling the combustion process; optimizing combustion helps reduce the emission of harmful substances and meets environmental protection requirements; the closed-loop feedback mechanism ensures that the system can respond to changes in a timely manner and maintain the stability and reliability of the unit operation; reasonable combustion control reduces equipment wear and helps extend the service life of the equipment;

[0068] In order to further optimize the above embodiment, the sensor network module includes:

[0069] A combustion chamber sensor unit is installed in each combustion chamber and is used to obtain the type of fuel involved in the combustion, the flow rate of each type of fuel at the initial moment and the total flow rate at the current moment, the surface area of ​​the inner wall of the combustion chamber, the temperature of the inner wall, the carbon dioxide component concentration at the initial moment, the unburned hydrocarbon component concentration at the initial moment, the carbon dioxide component concentration at the current moment, and the unburned hydrocarbon component concentration at the current moment; a number of measuring points are pre-set in each combustion chamber to monitor the temperature and pressure of each measuring point in real time;

[0070] A fan inlet sensor unit is mounted at the fan inlet and is used to obtain the air temperature at the fan inlet;

[0071] The flue sensor unit is installed in the flue and is used to obtain the types of main combustion products in the flue, the concentrations and specific heat capacities of various products, flue gas temperature, exhaust density and exhaust flow rate.

[0072] It should be noted that fuel type identification can be achieved by a variety of methods; one feasible way is to use spectral analysis technology, such as near infrared spectroscopy (NIR) or Raman spectroscopy; different fuels have unique spectral characteristics, and the fuel type can be determined by comparing the spectral signal collected by the sensor with the pre-established fuel spectrum database; for the mixed combustion of multiple fuels, by analyzing the intensity and position changes of different characteristic peaks in the spectrum, combined with multivariate statistical analysis methods (such as partial least squares method, etc.), the proportion of various fuels can be quantitatively analyzed, thereby determining the fuel type and its respective flow conditions at the initial moment and the current moment;

[0073] Flow measurement: For liquid fuels, turbine flowmeters or mass flowmeters can be used. Turbine flowmeters calculate flow by measuring the rotational speed of the liquid as it flows through the turbine blades. They have the advantages of high measurement accuracy and fast response speed, but they have certain requirements for the cleanliness of the fluid. Mass flowmeters directly measure the mass flow of the fluid, which is not affected by factors such as fluid density, temperature, and pressure. They have higher measurement accuracy, but are relatively expensive. For gas fuels, such as natural gas, differential pressure flowmeters (such as orifice flowmeters, venturi flowmeters, etc.) or thermal mass flowmeters can be used. Differential pressure flowmeters use the pressure difference generated when the fluid flows through the throttling device to measure the flow. They have a simple structure and low cost, but a relatively small range ratio. Thermal mass flowmeters work based on the principle of heat exchange between the fluid and the sensor. They have high measurement accuracy and a large range ratio. They are suitable for various gas flow measurements, but are relatively expensive.

[0074] Calculation of inner wall surface area: During the construction or installation of the combustion chamber, the inner wall surface area can be calculated by measuring the geometric parameters of the combustion chamber (such as radius, height, length, etc.);

[0075] Inner wall temperature measurement: Use thermocouples or thermal resistance thermometers to measure the inner wall temperature. Thermocouple thermometers use the thermoelectric effect to form a closed loop with two conductors of different metal materials. When the temperatures of the two contact points are different, a thermoelectric potential will be generated in the loop, and the temperature is determined by measuring the size of the thermoelectric potential. Thermocouple thermometers have the advantages of a wide measurement range and fast response speed, and are suitable for temperature measurement in high temperature environments. Thermal resistance thermometers use the characteristics of the resistance value of metal or semiconductor materials that changes with temperature to measure temperature. They have high measurement accuracy and good stability, but the measurement range is relatively narrow. Install the thermocouple or thermal resistance thermometer at a suitable position on the combustion chamber wall, connect it to the data acquisition system through a wire, and obtain the wall temperature data in real time.

[0076] For the measurement of the concentration of gas components such as carbon dioxide and unburned hydrocarbons, non-dispersive infrared (NDIR) gas sensors or electrochemical gas sensors can be used; NDIR gas sensors work based on the absorption characteristics of gases to infrared light of a specific wavelength. Different gases have specific absorption peaks in the infrared band. The gas concentration is determined by measuring the change in light intensity after the infrared light passes through the gas; the sensor has the advantages of good selectivity, high sensitivity, and strong stability, and is widely used in the detection of gases such as carbon dioxide; electrochemical gas sensors use the principle of electrochemical reactions. When the gas diffuses into the sensitive electrode of the sensor, an oxidation or reduction reaction occurs, generating a current signal proportional to the gas concentration, and the gas concentration is determined by measuring the current; electrochemical gas sensors have high sensitivity and selectivity to certain specific gases (such as carbon monoxide, hydrogen, etc.), and a fast response speed, but a relatively short service life, and require regular calibration and replacement; multiple gas sensors are installed in the combustion chamber, distributed in different locations, to obtain more comprehensive and accurate information on the concentration of gas components;

[0077] For temperature measurement, temperature sensors are installed at the pre-set measuring points in the combustion chamber. In addition to the thermocouples and thermal resistance thermometers mentioned above, fiber optic temperature sensors can also be considered. Fiber optic temperature sensors work on the principle that the optical transmission characteristics of optical fibers change with temperature. They have the advantages of strong anti-electromagnetic interference ability, high temperature resistance, corrosion resistance, and small size. They are suitable for temperature measurement in harsh environments. The temperature signals of multiple measuring points are transmitted to the data acquisition system through optical fibers to realize real-time monitoring of the temperature field in the combustion chamber.

[0078] Pressure measurement uses piezoresistive pressure sensors or capacitive pressure sensors to measure the pressure at the measuring point in the combustion chamber. Piezoresistive pressure sensors use the piezoresistive effect of semiconductor materials. When pressure acts on the sensitive element of the sensor, its resistance value will change. The pressure is determined by measuring the resistance change. Piezoresistive pressure sensors have the advantages of high accuracy, high sensitivity, and fast response speed, but they are sensitive to temperature changes and require temperature compensation. Capacitive pressure sensors work on the principle that the distance between the capacitor plates changes with pressure. They have high measurement accuracy, good stability, and small temperature drift, but their cost is relatively high. The pressure sensor is installed at the measuring point and connected to the data acquisition system through a wire to obtain the pressure distribution in the combustion chamber in real time.

[0079] The fan inlet sensor unit is mainly used to obtain the air temperature at the fan inlet, which can be achieved by using a platinum resistance thermometer; the platinum resistance thermometer uses the characteristic that the resistance value of the platinum wire changes with temperature, and there is a good linear relationship between its resistance and temperature (within a certain temperature range); the platinum resistance thermometer is installed at the fan inlet so that it can accurately measure the air temperature entering the fan; the resistance value change of the platinum resistor is converted into a voltage signal through the measurement circuit, and then transmitted to the data acquisition system for processing and analysis after analog-to-digital conversion (A / D); the platinum resistance thermometer has the advantages of high measurement accuracy, good stability, good reproducibility, etc., and can meet the requirements for measuring the air temperature at the fan inlet;

[0080] Combustion product types and concentrations are measured using a multi-component gas analyzer to measure the types and concentrations of the main combustion products in the flue. Multi-component gas analyzers usually work based on a variety of principles, such as Fourier transform infrared spectroscopy (FTIR), mass spectrometry (MS), etc. FTIR gas analyzers measure the absorption spectrum of infrared light after passing through the flue gas, and use the absorption peaks at different wavelengths in the spectrum to identify and quantitatively analyze various gas components. They can simultaneously detect a variety of combustion products (such as carbon monoxide, carbon dioxide, nitrogen oxides, sulfur dioxide, etc.), and have the advantages of high measurement accuracy, fast response speed, and good selectivity, but the equipment cost is high and maintenance is complex. Mass spectrometers ionize flue gas and separate and detect different gas components according to the mass-to-charge ratio of ions. They can provide high-sensitivity and high-resolution analysis results and are suitable for the detection of trace gas components, but the equipment is expensive and has high operating requirements. According to actual needs and cost considerations, select a suitable multi-component gas analyzer, install it at a suitable position in the flue, and introduce the flue gas into the analyzer through a sampling system for real-time analysis.

[0081] For the measurement of some specific combustion products, such as particulate matter concentration, a laser scattering particulate matter concentration sensor can be used; this sensor uses laser to illuminate the particulate matter in the flue, and the particulate matter will scatter the laser. The concentration and particle size distribution of the particulate matter are determined by measuring the intensity and angle change of the scattered light; the laser scattering particulate matter concentration sensor has the advantages of wide measurement range, fast response speed, non-contact measurement, etc., and can monitor the particulate matter emission in the flue in real time;

[0082] Specific heat capacity acquisition: The specific heat capacity of the main combustion products in the flue can be obtained through the pre-established combustion product specific heat capacity database; according to the types and concentrations of the combustion products measured by the multi-component gas analyzer, the corresponding specific heat capacity data are searched in the database; these specific heat capacity data can be obtained through experimental measurement or theoretical calculation, and corrected and updated according to different temperature ranges; in actual operation, combined with the temperature measurement value in the flue, the specific heat capacity data at the appropriate temperature is selected for subsequent heat calculation and other analysis;

[0083] Flue gas temperature measurement is similar to the temperature measurement in the combustion chamber. Thermocouples or thermal resistance thermometers can be used to measure the flue gas temperature in the flue. The temperature sensors are installed at different positions on the flue cross section, and the average flue gas temperature in the flue is calculated by averaging or weighted averaging. Since the flue environment is relatively harsh, there may be high temperature, high dust, corrosive gases, etc., so it is necessary to select temperature sensors with high temperature resistance, corrosion resistance, and strong anti-interference ability, and take corresponding protective measures, such as installing protective sleeves, etc.

[0084] Smoke density measurement: Smoke density can be calculated by measuring the temperature, pressure and composition of the smoke in the flue using the ideal gas state equation or other related gas state equations;

[0085] For exhaust flow measurement, a differential pressure flowmeter (such as a Pitot tube flowmeter) or an ultrasonic flowmeter can be used to measure the exhaust flow rate. The Pitot tube flowmeter is based on the principle of the Bernoulli equation and measures the dynamic pressure and static pressure of the flue gas to calculate the flow velocity, thereby obtaining the exhaust flow rate. The Pitot tube flowmeter has a simple structure and is easy to install, but the measurement accuracy is greatly affected by the airflow distribution in the flue, and it is necessary to reasonably select the installation location and perform necessary flow field corrections. The ultrasonic flowmeter uses the relationship between the propagation speed of ultrasonic waves in the fluid and the flow velocity to measure the flow rate. It has high measurement accuracy and is not affected by factors such as fluid density, pressure, and viscosity. It is a non-contact measurement with little interference to the airflow in the flue, but the equipment cost is relatively high. Select a suitable exhaust flow measurement method based on the actual situation of the flue and the measurement requirements, and install the flowmeter at a suitable position in the flue to ensure accurate and reliable measurement.

[0086] In order to further optimize the above embodiment, the data preprocessing module includes:

[0087] The data acquisition unit is used to receive various types of raw data collected by each sensor unit and store them according to data type and source to ensure the integrity and traceability of the data;

[0088] A filtering unit is connected to the data acquisition unit and processes the classified and stored data by using a median filtering method or a mean filtering method;

[0089] The calibration unit is connected to the data acquisition unit and calibrates the data collected by each sensor unit according to pre-set calibration parameters and data of the standard measuring device.

[0090] It should be noted that the interface circuit is designed according to the sensor output signal type (analog or digital) to convert it into a uniform and processable digital signal. The database is used to create tables and store data according to data type and source, including fields such as acquisition time, sensor identification and measurement value, to ensure that the data is orderly and traceable. Select a suitable protocol (such as Ethernet or serial port protocol) to transmit data, and ensure data integrity and accuracy through timestamp synchronization and data buffer.

[0091] Median filter implementation: set an odd-length filter window, sort the new data into the window and take the middle value output, and slide the window to process subsequent data to remove impulse noise.

[0092] Mean filtering operation: Determine the window size and calculate the average value of the data in the window as the output. It can suppress random noise and make the data smooth, but it is slightly inferior to edge details.

[0093] Preset calibration parameters according to sensor type and characteristics, such as zero offset, sensitivity coefficient, etc., and store them in the calibration parameter table. Or regularly compare the sensor acquisition values ​​with the measured values ​​of standard equipment, calculate the calibration value according to the error, and correct the sensor data with the calibration formula to ensure accuracy.

[0094] In order to further optimize the above embodiment, the indicator analysis module includes:

[0095] The energy balance model building unit is connected to the data acquisition unit and is used to build an energy balance model, analyze the heat generated by combustion, the heat taken away by combustion products, and the heat loss of the combustion chamber wall, and calculate the energy balance deviation index by solving the model to evaluate the energy utilization in the combustion process and the degree of deviation from the ideal equilibrium state;

[0096] A chemical equilibrium model building unit is connected to the data acquisition unit and is used to build a chemical equilibrium model, analyze the relationship between the actual measured concentration and the theoretical concentration based on the combustion reaction of the fuel, and calculate the chemical equilibrium index, so as to judge the degree and direction of the combustion reaction and whether there is an incomplete combustion phenomenon;

[0097] The combustion uniformity analysis model building unit is connected to the data acquisition unit and is used to build a combustion uniformity analysis model. By calculating the deviation between the temperature and pressure of each measuring point and the average temperature and pressure of the combustion chamber, the uniformity of combustion in the combustion chamber is comprehensively evaluated to obtain a combustion uniformity evaluation index, which is used to reflect the spatial uniformity of the combustion process.

[0098] It should be noted that the energy balance model is:

[0099] Q in =m f *Q LHV，tot *η comb

[0100]

[0101] Q out =Σm x *C p，x *(T flue -T air )

[0102] m x =C x * flue *V flue

[0103]

[0104]

[0105] Among them, E is the balance deviation index; Q un The heat released by fuel combustion, m f is the total fuel flow at the current moment, Q LHV，tot is the lower calorific value of the fuel, η comb is the combustion efficiency, combustion efficiency η comb Theoretical values ​​are used; k is the fuel type index, d is the total number of fuel types, m f，k is the initial flow rate of the kth fuel, Q LHV，k is the lower calorific value of the kth fuel;

[0106] Q out is the heat carried away by the combustion products, m x is the mass flow rate of combustion product x, C p，x is the specific heat capacity of the combustion product x, T flue is the exhaust gas temperature, T air is the air temperature; C x is the concentration of the combustion product x, ρ flue is the smoke density of the combustion product x, V flue is the exhaust flow rate of combustion product x;

[0107] Q loss is the heat loss from the combustion chamber wall, A w is the surface area of ​​the inner wall of the combustion chamber, T w is the inner wall temperature, T amb is the ambient temperature, n is the normal direction of the wall, is the normal temperature gradient of the wall, k w is the thermal conductivity of the combustion chamber wall material, h is the convective heat transfer coefficient, which represents the amount of heat transferred when the temperature difference between the fluid and the solid surface is one unit per unit time and per unit area during the convective heat transfer process. It is used to reflect the efficiency of heat transfer between the fluid and the solid wall, and its value is determined based on experiments.

[0108] The chemical equilibrium model is:

[0109]

[0110] Among them, ξ is the chemical balance index; [CO2] is the concentration of carbon dioxide at the current moment, [CO2]0 is the concentration of carbon dioxide at the initial moment, [C x H y ]0 is the concentration of unburned hydrocarbon components at the initial moment, [C x H y ] is the concentration of unburned hydrocarbon components at the current moment; s is the coefficient determined by the stoichiometric number in the chemical reaction process, representing the quantitative correspondence between the fuel and the combustion products in the chemical reaction.

[0111] The combustion uniformity analysis model is:

[0112]

[0113]

[0114]

[0115] Among them, U is the combustion uniformity evaluation index; is the average temperature of the combustion chamber, is the average pressure of the combustion chamber; N is the number of burners, M is the number of measuring points for each burner, T is j，i is the temperature of the jth burner and the ith measurement, P j，i is the pressure of the jth burner and the i-th measurement.

[0116] In order to further optimize the above embodiment, the control strategy execution module includes:

[0117] The energy balance strategy execution unit is connected to the energy balance model establishment unit. When the energy balance deviation index exceeds the preset energy balance threshold, the corresponding strategy is executed; if the energy input is less than the sum of the energy output and the loss, the fuel flow rate is increased according to the preset basic ratio, and the ratio value is determined according to the energy response characteristics of the unit and the current operating parameters; at the same time, according to the increase in the fuel flow rate, the air flow rate is adjusted accordingly according to the stoichiometric relationship to maintain a suitable air-fuel ratio; if the energy input is greater than the sum of the energy output and the loss, the exhaust temperature and wall heat loss are checked. If the exhaust temperature is too high, the air flow rate is appropriately increased to enhance the cooling effect; if the wall heat loss is abnormal, the insulation condition of the combustion chamber wall is checked or the operating parameters are adjusted to reduce the wall temperature gradient;

[0118] The chemical balance strategy execution unit is connected to the chemical balance model establishment unit. When the chemical balance index is lower than the preset chemical balance threshold, if the concentration of unburned hydrocarbons in the combustion chamber is too high, it indicates that the fuel is not fully burned. At this time, the air flow rate is increased, and the flame shape and position of the burner are adjusted, including changing the burner nozzle angle or internal structure to make the fuel and air mix better; if the oxygen concentration is too high, the air flow rate is reduced according to the preset basic ratio while ensuring stable combustion, and the uniformity and stability of the fuel supply system are checked to avoid local fuel dilution leading to reduced combustion efficiency;

[0119] The combustion uniformity strategy execution unit is connected to the combustion uniformity analysis model. When the combustion uniformity evaluation index is lower than the preset combustion uniformity threshold, for areas where the temperature is higher than the average temperature of the combustion chamber, the fuel flow of the burner in this area is reduced, and the reduction ratio is determined according to the size of the temperature deviation; at the same time, the air flow is fine-tuned to maintain a suitable air-fuel ratio; for areas where the temperature is lower than the average temperature, the fuel flow is increased and the air flow is adjusted accordingly; in addition, the personnel are notified to check whether the burner has blockage or wear failure that affects the uniform distribution of fuel and air.

[0120] It should be noted that the energy balance strategy:

[0121] 1.Threshold setting and monitoring;

[0122] According to the design parameters, historical operation data and relevant standards of the unit, set an appropriate energy balance threshold. The threshold can be a fixed value or a value dynamically adjusted according to factors such as unit load and fuel characteristics. For example, under low load conditions, the threshold of the energy balance deviation index can be relatively loose to adapt to the operating characteristics of the unit under this condition; under high load conditions, the threshold should be stricter to ensure efficient and stable operation. By real-time monitoring of the energy balance deviation index, it is determined whether it exceeds the set threshold.

[0123] 2. Fuel flow adjustment;

[0124] When it is determined that the energy input is less than the sum of the energy output and the loss, the fuel flow rate needs to be increased. First, the preset basic increase ratio of the fuel flow rate is determined based on the energy response characteristics of the unit (such as the relationship curve between the change in fuel flow rate and the change in power output) and the current operating parameters (such as the current load, combustion efficiency, exhaust temperature, etc.). For example, if the energy response characteristics of the unit indicate that a 10% increase in fuel flow rate can increase the power output by 8%, and the current operating parameters show that the combustion efficiency is low and the exhaust temperature is high, the preset basic increase ratio can be appropriately increased, such as set to 15%.

[0125] Then, the fuel flow rate is increased by controlling the regulating valve (such as an electric regulating valve or a pneumatic regulating valve) in the fuel supply system. The control signal of the regulating valve can be generated by the control system according to the calculated fuel flow adjustment amount, and the proportional-integral-differential (PID) control algorithm or other advanced control algorithms are used to ensure that the increase of fuel flow rate is smooth and accurate, and avoid the impact on the combustion process caused by sudden changes in flow rate.

[0126] 3. Air flow adjustment;

[0127] According to the increase in fuel flow, the required increase in air flow is calculated according to the stoichiometric relationship. For common hydrocarbon fuel combustion, the stoichiometric ratio (mass ratio of air to fuel) is known, for example, the stoichiometric ratio of natural gas combustion is about 17.2. According to the change in fuel flow, the corresponding theoretical increase in air flow is calculated.

[0128] The air flow is adjusted by adjusting the fan speed or the damper opening at the fan inlet. The fan speed is controlled by variable frequency speed regulation technology, and the motor frequency is adjusted in real time according to the air flow demand, thereby changing the fan output air volume. Or the air intake volume can be changed by adjusting the damper opening. During the adjustment process, feedback control mechanisms are also used, such as real-time monitoring of the actual air flow through an air flow sensor installed in the air duct, comparing it with the theoretically calculated air flow, and using PID control algorithms to fine-tune the fan speed or damper opening to maintain a suitable air-fuel ratio.

[0129] 4. Treatment of exhaust temperature and wall heat loss;

[0130] When the energy input is greater than the sum of the energy output and the loss, if the exhaust temperature is too high, it means that the combustion products have taken away too much heat, and the air flow needs to be increased to enhance the cooling effect. Through the above air flow adjustment method, gradually increase the air flow and monitor the changes in the exhaust temperature in real time. When the exhaust temperature drops to a reasonable range, stop increasing the air flow.

[0131] If the heat loss from the wall is abnormal, first check the insulation condition of the combustion chamber wall. The temperature distribution at different locations on the wall can be monitored by temperature sensors to determine whether there is a local temperature that is too low (it may be that the insulation layer is damaged, causing the heat to dissipate too quickly). If the insulation layer is found to be damaged, repair or replace it in time. At the same time, adjust the operating parameters, such as reducing the operating pressure of the combustion chamber (within a safe range) to reduce the heat conduction driving force, thereby reducing the wall temperature gradient; or optimize the combustion process to make the flame distribution more uniform and reduce the thermal radiation effect of local high temperature on the wall.

[0132] Chemical Balance Strategy:

[0133] 1.Threshold determination and concentration monitoring;

[0134] The chemical balance threshold is set in advance, and the determination of the threshold is based on factors such as the chemical composition of the fuel, the combustion reaction characteristics, and environmental protection requirements. The chemical balance index is calculated by real-time monitoring of the concentration of gas components such as carbon dioxide, unburned hydrocarbons and oxygen in the combustion chamber and compared with the set threshold.

[0135] 2. Air flow adjustment (incomplete combustion);

[0136] When the concentration of unburned hydrocarbons in the combustion chamber is too high, indicating that the fuel is not fully burned, the air flow needs to be increased. The amount of increase in air flow is determined based on the degree of excess of the unburned hydrocarbon concentration and the performance characteristics of the burner. The required additional air volume can be calculated using an empirical formula or based on the combustion reaction kinetics model.

[0137] By controlling the fan or air supply system, the air flow rate is adjusted according to the calculated increase. At the same time, the changes in the concentration of gas components in the combustion chamber are closely monitored. When the concentration of unburned hydrocarbons drops to a reasonable range and the chemical balance index approaches or reaches the threshold, the increase in air flow rate is stopped.

[0138] 3. Air flow adjustment (when oxygen concentration is too high);

[0139] If the oxygen concentration is too high, the air flow rate is reduced according to the preset basic ratio while ensuring stable combustion. The preset basic ratio is determined based on factors such as the stable combustion characteristics of the burner, the type of fuel, and the current operating load. For example, for some burners with good stable combustion performance, under low load conditions, when the oxygen concentration is slightly high, the air flow rate can be gradually reduced by 5%-10%.

[0140] In the process of reducing air flow, monitor combustion stability (such as by monitoring parameters such as flame pulsation frequency and pressure fluctuations in the combustion chamber) and combustion efficiency (by calculating the energy balance deviation index or monitoring pollutant emission concentration, etc.) in real time. If signs of unstable combustion are found (such as increased flame pulsation, increased pressure fluctuations, etc.), stop reducing air flow immediately and adjust appropriately to ensure stable combustion. At the same time, check the uniformity and stability of the fuel supply system, including checking whether the fuel nozzle is blocked and whether the working pressure of the fuel pump is stable. The uniformity of fuel supply can be ensured by regularly cleaning the fuel nozzle and maintaining the fuel pump, so as to avoid local fuel dilution that leads to reduced combustion efficiency.

[0141] 4. Burner adjustment;

[0142] Whether increasing or decreasing the air flow, the shape and position of the burner flame need to be adjusted at the same time to optimize the mixing effect of fuel and air. To change the burner nozzle angle, an electric actuator or a hydraulic drive device can be used. The optimal nozzle angle adjustment is calculated based on monitoring data such as the temperature field in the combustion chamber and the distribution of gas component concentrations. For example, if it is found that the concentration of unburned hydrocarbons in a certain area of ​​the combustion chamber is high, the nozzle angle of the corresponding burner can be adjusted toward that area to make the flame cover a wider range and promote full mixing of fuel and air.

[0143] Adjustments to the internal structure of the burner, such as changing the angle of the swirl blades or adding a turbulent device, require modification or replacement of parts during the unit shutdown period. These adjustment measures are intended to enhance the airflow disturbance in the combustion chamber and improve the uniformity of the fuel-air mixture, thereby improving the combustion effect, increasing combustion efficiency, and reducing pollutant emissions.

[0144] Combustion uniformity strategy:

[0145] 1.Threshold determination and temperature and pressure monitoring;

[0146] Set a combustion uniformity threshold, which is determined based on the unit's combustion performance requirements, equipment safety operation restrictions, and previous operating experience. Monitor the temperature and pressure data of each measuring point in the combustion chamber in real time, calculate the combustion uniformity evaluation index, and compare it with the threshold.

[0147] 2. Fuel flow adjustment (high temperature area);

[0148] When the area with a temperature higher than the average temperature of the combustion chamber is determined, the deviation between the temperature of the area and the average temperature is calculated. According to the deviation value, the reduction ratio of the fuel flow of the burner in the area is determined according to the preset temperature deviation-fuel flow adjustment ratio. For example, if the temperature deviation is between 50℃-100℃, the fuel flow reduction ratio can be set to 5%-10%.

[0149] By controlling the fuel regulating valve of a single burner in the fuel supply system, the fuel flow rate is reduced according to the calculated reduction ratio. During the adjustment process, pay close attention to the changes in the temperature distribution in the combustion chamber to ensure that the temperature in the high-temperature area is gradually reduced, while avoiding combustion instability caused by excessive reduction in fuel flow.

[0150] 3. Air flow adjustment (high temperature area);

[0151] While reducing the fuel flow of the burner in the high temperature area, fine-tune the air flow to maintain the appropriate air-fuel ratio. According to the reduction in fuel flow, the corresponding reduction in air flow is calculated according to the stoichiometric relationship. Use a high-precision air flow control valve (such as an electric proportional control valve) to fine-tune the air flow according to the calculation results.

[0152] The oxygen sensor or combustion product component analyzer installed near the burner monitors the oxygen content or carbon monoxide content after combustion in real time to determine whether the air-fuel ratio is appropriate. If the oxygen content is too high or the carbon monoxide content is too low, it means that the air flow is relatively excessive, and the air flow should be further reduced; otherwise, the air flow should be increased appropriately to ensure that the combustion process is carried out at the optimal air-fuel ratio, improve combustion efficiency, and reduce pollutant emissions.

[0153] 4. Fuel flow adjustment (low temperature area);

[0154] For areas where the temperature is lower than the average temperature, the temperature deviation value is calculated, and the increase ratio of the fuel flow is determined according to the deviation value. For example, when the temperature deviation is between -50℃ and 100℃, the increase ratio of the fuel flow can be set to 5%-10%. By controlling the fuel regulating valve of the corresponding burner, the fuel flow is increased, the temperature of the low temperature area is increased, and the temperature in the combustion chamber is evenly distributed.

[0155] 5. Air flow adjustment (low temperature area);

[0156] According to the increase in fuel flow, the required increase in air flow is calculated based on the stoichiometric relationship. By adjusting the air supply system, the air flow of the burner in the low-temperature area is increased to ensure that the combustion process is carried out at a suitable air-fuel ratio. Similarly, the air-fuel ratio is monitored in real time using monitoring equipment such as oxygen sensors, and fine-tuned based on the monitoring results to ensure sufficient and stable combustion.

[0157] 6. Burner fault inspection notification;

[0158] When the combustion uniformity evaluation index is lower than the threshold, in addition to adjusting the fuel and air flow, the system automatically notifies relevant personnel to check whether the burner has blockage, wear and other faults. The control system can send alarm information to the monitoring center or the mobile devices of relevant personnel to prompt them to check the burner nozzle, air duct, flame stabilizer and other components.

[0159] After receiving the notification, the staff will conduct a detailed inspection of the burner. For blockage problems, high-pressure gas purging, mechanical cleaning and other methods can be used to remove the blockage; for severely worn parts, such as burner nozzles, swirl blades, etc., they should be replaced in time to restore the normal working performance of the burner, ensure the uniform distribution of fuel and air, and improve the uniformity of combustion. After troubleshooting, restart the combustion uniformity monitoring and adjustment process to ensure the continuous and stable operation of the unit.

[0160] In order to further optimize the above embodiment, the feedback adjustment module includes:

[0161] A feedback signal acquisition unit is used to receive in real time new data collected by each sensor unit after the control strategy is executed, and form a feedback signal set to reflect the change of the combustion state after the control strategy is executed;

[0162] The cyclic adjustment unit is connected to the feedback signal acquisition unit and the index analysis module, and is used to transmit the feedback signal set to the index analysis module to start a new index analysis process; based on the new index results, the control strategy execution module performs threshold judgment and strategy execution again, and the cycle is repeated to achieve dynamic optimization of the combustion process; during the cycle, the control parameters are continuously adjusted to adapt to changes in the unit operation process to ensure that the unit always maintains a combustion state close to the optimal state.

[0163] It should be noted that the data receiving interface compatible with each sensor unit is designed to ensure that new data collected by different types of sensors can be stably and efficiently received; the interface can realize real-time data transmission based on existing communication protocols such as Ethernet, RS-485, etc.; for the specific data formats of different sensors, they are parsed and converted at the interface and unified into a standard format that the system can handle, which is convenient for subsequent data processing and analysis;

[0164] For example, for the analog voltage signal transmitted by the temperature sensor, after analog-to-digital conversion, it is packaged at the interface according to a pre-set data structure, including information such as sensor identification, acquisition time, temperature value, etc., to form a standardized data record;

[0165] Establish a data buffer area to temporarily store new data received; since the frequency of sensor data collection may be high and the subsequent analysis and processing may not be completed in real time, the data buffer area can avoid data loss; at the same time, the data in the buffer area is classified and integrated according to the source (such as combustion chamber, fan inlet, flue, etc.) and type (temperature, pressure, gas composition, etc.) of the data to form a feedback signal set;

[0166] For example, the temperature data from each measuring point in the combustion chamber is stored in an array according to the order of the measuring point positions, and the pressure data is stored in another array, so as to facilitate the rapid call of relevant data in the subsequent calculation of indicators such as combustion uniformity;

[0167] Establish an efficient data transmission channel between the feedback signal acquisition unit and the indicator analysis module to ensure that the feedback signal set can be transmitted to the indicator analysis module in a timely and accurate manner; an event-driven mechanism can be adopted. When the feedback signal acquisition unit receives a new complete feedback signal set, it immediately triggers the loop adjustment unit to start the data transmission operation and send the signal set to the indicator analysis module;

[0168] For example, asynchronous data transmission can be achieved through middleware such as message queues to ensure the reliability and timeliness of data transmission and avoid the impact of data transmission delays on the dynamic optimization effect of the system.

[0169] After the index analysis module receives the feedback signal set, it immediately starts a new index analysis process to recalculate the energy balance deviation index, chemical balance index and combustion uniformity evaluation index, etc.; based on the new index results, the control strategy execution module performs threshold determination again;

[0170] If the indicator still exceeds the corresponding threshold, the control strategy execution module performs corresponding adjustment operations according to the preset strategy, such as adjusting the fuel flow, air flow, burner status, etc. After the adjustment is completed, the feedback signal acquisition unit receives new data again to form a new feedback signal set, and the cycle is repeated to continuously optimize the combustion process;

[0171] During the cycle, the system continuously adjusts control parameters based on long-term accumulated operating data and real-time monitoring of the unit's operating status; for example, according to the combustion characteristics under different load conditions, the system dynamically adjusts control parameters such as the fuel flow increase ratio in the energy balance strategy and the air flow adjustment step in the chemical balance strategy, so that the system can better adapt to various changes in the unit's operation process, such as fuel quality fluctuations, changes in ambient temperature and humidity, etc., to ensure that the unit always remains in a near-optimal combustion state.

[0172] In order to further optimize the above embodiment, a visualization module is also included; the visualization module is used to display the analysis results of various indicators, the strategy execution process and the feedback signal set to the management personnel.

[0173] It should be noted that a user-friendly front-end interface is developed to display various data information; the interface layout can be divided into multiple areas, such as the indicator analysis result display area, the strategy execution process monitoring area and the feedback signal real-time display area;

[0174] In the indicator analysis result display area, charts (such as line charts, bar charts, dashboards, etc.) are used to intuitively display the changing trends of various indicators over time; for example, a line chart is used to display the fluctuations of the energy balance deviation index over a period of time, so that managers can clearly see the changes in the energy balance state during the combustion process; a dashboard is used to display the values ​​of the current chemical balance index and combustion uniformity evaluation index and their relationship with the threshold, so as to quickly determine whether the combustion state is normal;

[0175] The strategy execution process monitoring area presents the execution steps, execution time and execution results of the control strategy in the form of a list or flow chart; for example, when the energy balance strategy execution unit adjusts the fuel flow, the area displays information such as "[time] adjusted fuel flow, target value [X], current execution status [success / failure]", so that managers can understand the strategy execution status in real time and discover problems in the execution process in a timely manner;

[0176] The feedback signal real-time display area displays key data in the feedback signal set in the form of a table or dynamic curve, such as the temperature, pressure, gas component concentration and other real-time data of each measuring point; the data update frequency can be set to ensure that managers can see the latest combustion status information; at the same time, for abnormal data (such as temperature and pressure values ​​outside the normal range, etc.), eye-catching colors or warning icons are used to mark them to remind managers to pay attention;

[0177] At the same time, it provides interactive functions to facilitate managers to operate and view more detailed information. For example, by setting a time selector on the interface, managers can choose to view the indicator change trend within a specific time period. For the data displayed in the chart, it provides functions such as zooming and panning to facilitate in-depth analysis of data details.

[0178] When the administrator clicks on a step in the policy execution process, detailed execution parameters and related log information will pop up to help the administrator troubleshoot problems. In addition, the alarm function can be set. When the indicator exceeds the preset critical threshold or the policy execution fails, the administrator will be alerted by sound, pop-up window, etc. to ensure timely measures.

[0179] Establish a data storage mechanism to store various types of acquired data (including indicator analysis results, strategy execution process information, feedback signal collection, etc.) in a database (such as relational database MySQL or time series database InfluxDB, etc.) to facilitate historical data query and analysis;

[0180] At the same time, a historical data query interface is developed, and managers can obtain detailed data records for a certain period of time in the past by entering query conditions (such as time range, indicator name, etc.); this helps managers to perform performance analysis, troubleshoot, and evaluate the operating effects of the combustion optimization control system, and provide data support for further optimization of the system; for example, by querying historical data, analyzing the changing patterns of the combustion process in different seasons or different fuel batches, providing a reference basis for adjusting the control strategy.

[0181] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A combustion optimization control system for a low-load unit, characterized in that: include: A sensor network module, which is used to collect key parameters of the combustion process of the unit when it is running at low load; the key parameters include combustion chamber operating parameters, fan inlet operating parameters and flue operating parameters; A data preprocessing module, which is connected to the sensor network module and is used to preprocess the collected key parameters, wherein the preprocessing process includes filtering and calibration processing; An index analysis module, which is connected to the data preprocessing module, establishes an energy balance model, a chemical balance model and a combustion uniformity analysis model based on the key parameters after preprocessing, and determines the energy balance deviation degree index, chemical balance index and combustion uniformity evaluation index of the current unit through model analysis; A control strategy execution module, which is connected to the index analysis module and is used to perform threshold determination on the results of each index, and execute preset energy balance strategy, chemical balance strategy and combustion uniformity strategy based on the determination results to optimize the combustion process; The feedback adjustment module is connected to the index analysis module and the control strategy execution module, and is used to obtain the feedback signal after execution, and perform a new index analysis and cyclic adjustment to form a closed-loop feedback mechanism.

2. A combustion optimization control system for low-load units according to claim 1, characterized in that: The sensor network module comprises: A combustion chamber sensor unit is installed in each combustion chamber and is used to obtain the type of fuel involved in the combustion, the flow rate of each type of fuel at the initial moment and the total flow rate at the current moment, the surface area of ​​the inner wall of the combustion chamber, the temperature of the inner wall, the carbon dioxide component concentration at the initial moment, the unburned hydrocarbon component concentration at the initial moment, the carbon dioxide component concentration at the current moment, and the unburned hydrocarbon component concentration at the current moment; a number of measuring points are pre-set in each combustion chamber to monitor the temperature and pressure of each measuring point in real time; A fan inlet sensor unit is mounted at the fan inlet and is used to obtain the air temperature at the fan inlet; The flue sensor unit is installed in the flue and is used to obtain the types of main combustion products in the flue, the concentrations and specific heat capacities of various products, flue gas temperature, exhaust density and exhaust flow rate.

3. A combustion optimization control system for low load of a unit according to claim 2, characterized in that: The data preprocessing module comprises: The data acquisition unit is used to receive various types of raw data collected by each sensor unit and store them according to data type and source to ensure the integrity and traceability of the data; A filtering unit, connected to the data acquisition unit, uses a median filtering method or a mean filtering method to process the classified and stored data; The calibration unit is connected to the data acquisition unit and calibrates the data collected by each sensor unit according to preset calibration parameters and data of a standard measuring device.

4. A combustion optimization control system for low load of a unit according to claim 3, characterized in that: The indicator analysis module includes: An energy balance model building unit, which is connected to the data acquisition unit and is used to build an energy balance model, analyze the heat generated by combustion, the heat taken away by combustion products, and the heat loss of the combustion chamber wall, and calculate the energy balance deviation index by solving the model to evaluate the energy utilization in the combustion process and the degree of deviation from the ideal equilibrium state; A chemical equilibrium model building unit, which is connected to the data acquisition unit and is used to build a chemical equilibrium model, analyze the relationship between the actual measured concentration and the theoretical concentration based on the combustion reaction of the fuel, and calculate the chemical equilibrium index, so as to judge the degree and direction of the combustion reaction and whether there is incomplete combustion; The combustion uniformity analysis model building unit is connected to the data acquisition unit and is used to build a combustion uniformity analysis model. By calculating the deviation between the temperature and pressure of each measuring point and the average temperature and pressure of the combustion chamber, the uniformity of combustion in the combustion chamber is comprehensively evaluated to obtain a combustion uniformity evaluation index, which is used to reflect the spatial uniformity of the combustion process.

5. A combustion optimization control system for low load of a unit according to claim 4, characterized in that: The energy balance model is: Q in =m f *Q LHV，tot *η comb Q out =∑m x *C p，x *(T flue -T air ) m x =C x *r flue *V flue Among them, E is the balance deviation index; Qi n The heat released by fuel combustion, m f is the total fuel flow at the current moment, Q LHV,tot is the lower calorific value of the fuel, η comb is the combustion efficiency, combustion efficiency η comb Theoretical values ​​are used; k is the fuel type index, d is the total number of fuel types, m f，k is the initial flow rate of the kth fuel, Q LHV，k is the lower calorific value of the kth fuel; Q out is the heat carried away by the combustion products, m x is the mass flow rate of combustion product x, C p，x is the specific heat capacity of the combustion product x, T flue is the exhaust gas temperature, T air is the air temperature; C x is the concentration of the combustion product x, ρ flue is the smoke density of the combustion product x, V flue is the exhaust flow rate of combustion product x; Q loss is the heat loss from the combustion chamber wall, A w is the surface area of ​​the inner wall of the combustion chamber, T w is the inner wall temperature, T amb is the ambient temperature, n is the normal direction of the wall, is the normal temperature gradient of the wall, k w is the thermal conductivity of the combustion chamber wall material, h is the convective heat transfer coefficient, which represents the amount of heat transferred when the temperature difference between the fluid and the solid surface is one unit per unit time and per unit area during the convective heat transfer process. It is used to reflect the efficiency of heat transfer between the fluid and the solid wall, and its value is determined based on experiments.

6. A combustion optimization control system for low-load units according to claim 5, characterized in that: The chemical equilibrium model is: Among them, ξ is the chemical balance index; [CO2] is the concentration of carbon dioxide at the current moment, [O2]0 is the concentration of carbon dioxide at the initial moment, [C x H y ]0 is the concentration of unburned hydrocarbon components at the initial moment, [C x H y ] is the concentration of unburned hydrocarbon components at the current moment; s is the coefficient determined by the stoichiometric number in the chemical reaction process, representing the quantitative correspondence between the fuel and the combustion products in the chemical reaction.

7. A combustion optimization control system for low-load units according to claim 6, characterized in that: The combustion uniformity analysis model is: Among them, U is the combustion uniformity evaluation index; is the average temperature of the combustion chamber, is the average pressure of the combustion chamber; N is the number of burners, M is the number of measuring points for each burner, T is j , i is the temperature of the jth burner and the ith measurement, P j , i is the pressure of the jth burner and the i-th measurement.

8. A combustion optimization control system for low-load units according to claim 7, characterized in that: The control strategy execution module includes: An energy balance strategy execution unit is connected to the energy balance model establishment unit, and when the energy balance deviation index exceeds a preset energy balance threshold, a corresponding strategy is executed; if the energy input is less than the sum of the energy output and the loss, the fuel flow rate is increased according to a preset basic ratio, and the ratio value is determined according to the energy response characteristics of the unit and the current operating parameters; at the same time, according to the increase in the fuel flow rate, the air flow rate is adjusted accordingly according to the stoichiometric relationship to maintain a suitable air-fuel ratio; if the energy input is greater than the sum of the energy output and the loss, the exhaust temperature and the wall heat loss are checked, and if the exhaust temperature is too high, the air flow rate is appropriately increased to enhance the cooling effect; if the wall heat loss is abnormal, the insulation condition of the combustion chamber wall is checked or the operating parameters are adjusted to reduce the wall temperature gradient; A chemical balance strategy execution unit is connected to the chemical balance model establishment unit. When the chemical balance index is lower than a preset chemical balance threshold, if the concentration of unburned hydrocarbons in the combustion chamber is too high, indicating that the fuel is not fully burned, the air flow rate is increased, and the flame shape and position of the burner are adjusted, including changing the burner nozzle angle or internal structure, so that the fuel and air are better mixed; if the oxygen concentration is too high, the air flow rate is reduced according to a preset basic ratio while ensuring stable combustion, and the uniformity and stability of the fuel supply system are checked to avoid local fuel being too thin, resulting in reduced combustion efficiency; A combustion uniformity strategy execution unit is connected to the combustion uniformity analysis model establishment unit. When the combustion uniformity evaluation index is lower than a preset combustion uniformity threshold, for areas where the temperature is higher than the average temperature of the combustion chamber, the fuel flow of the burner in this area is reduced, and the reduction ratio is determined according to the size of the temperature deviation; at the same time, the air flow is fine-tuned to maintain a suitable air-fuel ratio; for areas where the temperature is lower than the average temperature, the fuel flow is increased and the air flow is adjusted accordingly; in addition, personnel are notified to check whether the burner has blockage or wear failure that affects the uniform distribution of fuel and air.

9. A combustion optimization control system for low-load units according to claim 8, characterized in that: The feedback adjustment module comprises: A feedback signal acquisition unit is used to receive in real time new data collected by each sensor unit after the control strategy is executed, and form a feedback signal set to reflect the change of the combustion state after the control strategy is executed; A cyclic adjustment unit is connected to the feedback signal acquisition unit and the index analysis module, and is used to transmit the feedback signal set to the index analysis module to start a new index analysis process; based on the new index result, the control strategy execution module performs threshold judgment and strategy execution again, and the cycle is repeated to achieve dynamic optimization of the combustion process; during the cycle, the control parameters are continuously adjusted to adapt to changes in the unit operation process to ensure that the unit always maintains a combustion state close to the optimal state.

10. A combustion optimization control system for a low-load unit according to claim 9, characterized in that: It also includes a visualization module; the visualization module is used to display the analysis results of various indicators, the strategy execution process and the feedback signal set to the management personnel.

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