Method and system for determining air leakage rate of air pre-heater

Abstract

The invention provides a method and system for determining the air leakage rate of an air pre-heater, and relates to the technical field of heat energy engineering.The method comprises the steps that smoke and air parameters of an inlet and an outlet of the current air pre-heater are obtained and preprocessed; an enthalpy value calculation model is established, and enthalpy values corresponding to the smoke and air parameters of the inlet and outlet of the current air pre-heater are calculated through the enthalpy value calculation model; analyzing based on the obtained enthalpy values, and calculating and recording the current air leakage rate; the current air leakage rate is stored in a historical database, and the air leakage rate change condition is analyzed; according to the invention, the monitoring precision and data quality of the air leakage rate can be improved, and the calculation process is simplified; the air leakage rate change is predicted through trend analysis, and preventive maintenance is supported; the energy efficiency is effectively improved and the maintenance cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of thermal energy engineering, and in particular to a method and system for determining an air preheater leakage rate. Background Art

[0002] In modern industrial production, especially in large-scale heat energy utilization occasions such as thermal power plants and chemical plants, boilers play a vital role as one of the core equipment; in order to improve thermal efficiency and reduce emission pollution, air preheaters are widely used in boiler systems. Their function is to use the waste heat of exhaust flue gas to heat the air sent into the boiler to improve combustion efficiency;

[0003] With the advancement of technology, the design and manufacturing process of air preheaters are also constantly developing; early air preheaters were mostly fixed heat exchange devices, while modern air preheaters pay more attention to efficient heat transfer, low resistance design and long life operation; in addition, with the trend of digital transformation, more and more intelligent monitoring and control systems are integrated into air preheaters to achieve more sophisticated operation management and maintenance;

[0004] Although air preheater technology has made significant progress, there are still some problems in practical application, especially in operation monitoring. During long-term operation, air preheaters are prone to air leakage due to wear, deformation and other factors, resulting in unexpected air inflow and affecting the thermal efficiency of the boiler system. Existing monitoring methods often rely on indirect estimation or regular manual inspections, which are difficult to accurately reflect changes in leakage rate in real time. In addition, the flue gas and air parameters at the inlet and outlet of the air preheater include multiple variables, and the processing of these data is relatively complicated. At the same time, the trend analysis of the air preheater leakage rate can help predict possible problems in the future, but there is currently a lack of effective tools for such analysis. Summary of the invention

[0005] The present invention provides a method and system for determining the air leakage rate of an air preheater, which are used to solve the technical problems existing in the prior art regarding air leakage rate monitoring of an air preheater, and provide support for improving the operating efficiency of the air preheater, reducing energy consumption and maintenance costs.

[0006] In one aspect, the present invention provides a method for determining an air preheater leakage rate, comprising:

[0007] Step 1: Obtain the current flue gas and air parameters at the inlet and outlet of the air preheater and perform preprocessing;

[0008] Step 2: Establish an enthalpy calculation model, and calculate the enthalpy values ​​corresponding to the flue gas and air parameters at the inlet and outlet of the current air preheater through the enthalpy calculation model;

[0009] Step 3: Analyze the enthalpy values ​​obtained in step 2, calculate and record the current air leakage rate;

[0010] Step 4: Store the current air leakage rate in a historical database and analyze changes in the air leakage rate.

[0011] According to the method for determining the air preheater leakage rate of the present invention, in step 1, the flue gas and air parameters at the inlet and outlet of the air preheater include: air preheater inlet flue gas parameters, air preheater outlet flue gas parameters, air preheater inlet air parameters, and air preheater outlet air parameters;

[0012] The air preheater inlet flue gas parameters include: inlet flue gas temperature, volume percentage of each component in the inlet flue gas, and constant pressure specific heat capacity of each component in the inlet state;

[0013] The flue gas parameters at the air preheater outlet include: outlet flue gas temperature, volume percentage of each component in the outlet flue gas, and specific heat capacity of each component at constant pressure in the outlet state;

[0014] The air preheater inlet air parameters include: inlet air temperature and constant pressure specific heat capacity of air at the inlet state;

[0015] The air parameters at the air preheater outlet include: outlet air temperature and constant pressure specific heat capacity of the air at the outlet state.

[0016] According to the method for determining the air preheater leakage rate of the present invention, the volume percentage of each component in the inlet and outlet flue gas is the volume ratio of each component gas in the inlet and outlet flue gas per unit volume, which is used to reflect the relative content of each component gas in the flue gas entering or discharged from the air preheater;

[0017] The type of each component gas is preset, and the flue gas is detected by a flue gas analyzer installed at the inlet and outlet of the air preheater to obtain the volume percentage of each component in the inlet and outlet flue gas.

[0018] According to the method for determining the air preheater leakage rate of the present invention, in step 1, the preprocessing process includes: data cleaning, data conversion and data calibration;

[0019] The data cleaning step includes checking the integrity of the data to ensure that each parameter obtained has a specific value and there are no missing items; and removing outliers by setting a reasonable range or using statistical methods to identify and eliminate obviously unreasonable data points;

[0020] The data conversion step includes unifying the units of temperature and specific heat capacity parameters so as to be used in subsequent enthalpy calculations;

[0021] The data calibration step includes calibrating the acquired parameters based on the errors and drifts of the sensor and the flue gas analyzer.

[0022] According to the method for determining the air preheater leakage rate of the present invention, in step 2, the enthalpy value calculation model includes an inlet flue gas enthalpy value model, an outlet flue gas enthalpy value model, an inlet air enthalpy value model, and an outlet air enthalpy value model;

[0023] The inlet flue gas enthalpy model is:

[0024]

[0025] Among them, H in is the inlet flue gas enthalpy, i represents the component type, C p，i，in is the constant pressure specific heat capacity of component i at the inlet state, V i，in is the volume percentage of component i at the inlet state; T in is the inlet flue gas temperature, T ref is the reference temperature, used to determine a relative zero point when calculating enthalpy;

[0026] The outlet flue gas enthalpy model is:

[0027]

[0028] Among them, H out is the outlet flue gas enthalpy value, i represents the component type, C p，i，out is the constant pressure specific heat capacity of component i at the outlet state, V i，out is the volume percentage of component i at the outlet state; T out is the outlet flue gas temperature;

[0029] The inlet air enthalpy model is:

[0030] H ain =C p，air，in *{T ain -T ref}

[0031] Among them, H ain is the inlet air enthalpy, C p，air，in is the constant pressure specific heat capacity of air at the inlet state, T ain is the inlet air temperature;

[0032] The outlet air enthalpy model is:

[0033] H aout =C p，air，out *{T aout -T ref}

[0034] Among them, H aout is the outlet air enthalpy, C p，air，out is the constant pressure specific heat capacity of air at the outlet state, T aoutis the outlet air temperature;

[0035] Substitute the flue gas and air parameters at the inlet and outlet of the air preheater into the above model, and calculate the inlet flue gas enthalpy H in , outlet flue gas enthalpy H out , inlet air enthalpy H ain And the outlet air enthalpy H aout .

[0036] According to the method for determining the air preheater leakage rate of the present invention, in step three, the enthalpy values ​​obtained in step two are analyzed, and the current leakage rate is calculated and recorded, which specifically includes:

[0037] The calculated inlet flue gas enthalpy H in , outlet flue gas enthalpy H out , inlet air enthalpy H ain And the outlet air enthalpy H aout Substitute into the following formula to calculate the current air preheater leakage rate L;

[0038]

[0039] Insert a timestamp into the data attribute of the current air preheater leakage rate L.

[0040] According to a method for determining the air preheater leakage rate of the present invention, in step four, the leakage rate L of the air preheater carrying a timestamp is stored in the historical database, and a line graph of the leakage rate changing with time is drawn, and the leakage rate of the air preheater at a future moment is predicted by time series analysis technology; the statistical image and the predicted value are displayed on the terminal device of the manager, and the leakage rate change at the current moment and the future moment is provided to the manager.

[0041] On the other hand, the present invention provides an air preheater leakage rate determination system, based on the above-mentioned air preheater leakage rate determination method, comprising:

[0042] A data acquisition module is provided at the inlet and outlet of the air preheater to obtain the current flue gas and air parameters at the inlet and outlet of the air preheater;

[0043] A front-end preprocessing module, which is connected to the data acquisition module and is used to preprocess the flue gas and air parameters at the inlet and outlet of the current air preheater, wherein the preprocessing process includes data cleaning, data conversion and data calibration;

[0044] An enthalpy analysis module is connected to the front-end preprocessing module, and an enthalpy calculation model is pre-established, and the enthalpy values ​​corresponding to the flue gas and air parameters at the inlet and outlet of the current air preheater are calculated by the enthalpy calculation model;

[0045] An air leakage rate calculation module, which is connected to the enthalpy value analysis module, performs analysis based on the obtained enthalpy values, calculates and records the current air leakage rate;

[0046] A statistical module is connected to the air leakage rate calculation module and is used to insert a timestamp into the data attribute of the current air preheater's air leakage rate and store it in the historical database. At the same time, a line graph is drawn about the change of the air leakage rate over time, and the air leakage rate of the air preheater at a future moment is predicted by time series analysis technology; the statistical image and the predicted value are displayed on the terminal device of the manager, and the change of the air leakage rate at the current moment and the future moment is provided to the manager.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. Improve monitoring accuracy: By real-time acquisition and accurate calculation of the flue gas and air parameters at the inlet and outlet of the air preheater, the present invention can provide more accurate air leakage rate monitoring results, which improves the monitoring accuracy and reliability compared with traditional methods;

[0049] 2. Optimize data quality: Data preprocessing steps (including data cleaning, conversion and calibration) ensure the integrity and validity of input data and reduce the risk of misjudgment due to data quality issues;

[0050] 3. Simplify the calculation process: The clear enthalpy calculation model simplifies the calculation process of air leakage rate, making it easier to get results quickly and also conducive to automatic monitoring;

[0051] 4. Trend analysis and prediction: By storing historical data and performing trend analysis, the present invention can predict the future trend of air leakage rate changes, provide a basis for preventive maintenance, and thus reduce unexpected downtime and maintenance costs;

[0052] 5. Improve energy efficiency: Accurate monitoring of air leakage rate helps to timely adjust the working state of the air preheater and reduce unnecessary heat loss, thereby improving energy utilization and the efficiency of the entire boiler system;

[0053] 6. Reduce maintenance costs: By continuously monitoring the air leakage rate, potential sealing problems or other failures can be discovered in time, thereby reducing maintenance costs and downtime;

[0054] 7. Improve operation management: Provide managers with real-time changes and predicted values ​​of air leakage rate, which helps to better manage the operation status of the air preheater and improve the overall operation level;

[0055] 8. Reduce environmental pollution: While improving thermal efficiency, it also reduces the possibility of pollutant emissions, which helps protect the environment.

[0056] 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.

[0057] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] 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:

[0059] Figure 1 It is a flow chart of a method for determining an air preheater leakage rate provided by an embodiment of the present invention;

[0060] Figure 2 It is a structural schematic diagram of an air preheater leakage rate determination system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0061] 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.

[0062] Embodiment 1:

[0063] The present invention provides a method for determining the air leakage rate of an air preheater, see Figure 1 ,include:

[0064] Step 1: Obtain the current flue gas and air parameters at the inlet and outlet of the air preheater and perform preprocessing;

[0065] Step 2: Establish an enthalpy calculation model, and calculate the enthalpy values ​​corresponding to the flue gas and air parameters at the inlet and outlet of the current air preheater through the enthalpy calculation model;

[0066] Step 3: Analyze the enthalpy values ​​obtained in step 2, calculate and record the current air leakage rate;

[0067] Step 4: Store the current air leakage rate in a historical database and analyze changes in the air leakage rate.

[0068] The principle of the above embodiment is: by measuring the flue gas and air parameters at the inlet and outlet of the air preheater, combined with the enthalpy calculation model, the energy transfer inside the air preheater can be determined; according to the law of conservation of energy, the energy at the inlet (including the enthalpy of the flue gas and air) and the energy at the outlet (including the enthalpy of the flue gas and air and the enthalpy of the possible leaked air) should be equal; this principle is used to solve the air leakage rate, that is, the proportion of the amount of air leaking into the air preheater to the theoretical amount of air;

[0069] Enthalpy is the energy content of a substance in a specific state, which is related to parameters such as temperature, pressure and composition. By measuring parameters such as inlet and outlet temperature, pressure and component volume percentage, and combining the constant pressure specific heat capacity of each component, the enthalpy of inlet and outlet flue gas and air can be calculated.

[0070] The enthalpy calculation model takes into account the contribution of different components and the effect of temperature change on enthalpy, thus more accurately reflecting the energy state inside the air preheater;

[0071] In order to ensure the accuracy of enthalpy calculation and air leakage rate determination, the acquired parameters need to be preprocessed; the data cleaning step removes outliers and missing items to ensure the reliability of the data; the data conversion step unifies the units to facilitate subsequent calculations; the data calibration step takes into account the errors and drifts of the sensor and flue gas analyzer to improve the accuracy of the data;

[0072] By storing the current air leakage rate in the historical database, long-term monitoring and analysis of the air leakage rate can be achieved; by analyzing the change of the air leakage rate over time, the operating status and performance change trend of the air preheater can be understood;

[0073] The beneficial effects of the above-mentioned embodiments are as follows: the present application comprehensively considers multiple parameters, and improves the accuracy of determining the air leakage rate by establishing an accurate enthalpy calculation model and data preprocessing steps; compared with traditional methods, it can more accurately reflect the actual air leakage situation of the air preheater; the current air leakage rate can be calculated and recorded in real time, and stored in a historical database; by drawing a line chart and performing time series analysis, the changing trend of the air leakage rate can be intuitively understood, and the future air leakage rate can be predicted, providing timely information for equipment management and maintenance; accurate air leakage rate data can help managers promptly discover air leakage problems in the air preheater, take corresponding maintenance measures, and improve the reliability and operation efficiency of the equipment; at the same time, by analyzing the changing trend of the air leakage rate, the operating parameters of the equipment can be optimized, and energy consumption and operating costs can be reduced.

[0074] In order to further optimize the above embodiment, in step 1, the flue gas and air parameters at the inlet and outlet of the air preheater include: air preheater inlet flue gas parameters, air preheater outlet flue gas parameters, air preheater inlet air parameters, and air preheater outlet air parameters;

[0075] The flue gas parameters at the air preheater inlet include: the inlet flue gas temperature, the volume percentage of each component in the inlet flue gas, and the constant pressure specific heat capacity of each component at the inlet state;

[0076] The flue gas parameters at the air preheater outlet include: outlet flue gas temperature, volume percentage of each component in the outlet flue gas, and specific heat capacity of each component at constant pressure at the outlet state;

[0077] The air preheater inlet air parameters include: inlet air temperature and constant pressure specific heat capacity of air at the inlet state;

[0078] The air parameters at the air preheater outlet include: outlet air temperature and constant pressure specific heat capacity of the air at the outlet state.

[0079] It should be noted that these detailed parameters can more comprehensively reflect the flue gas and air status at the inlet and outlet of the air preheater, providing a more accurate data basis for the subsequent enthalpy calculation and air leakage rate determination;

[0080] By considering the flue gas parameters and air parameters at the inlet and outlet respectively, the energy transfer and changes inside the air preheater can be analyzed more accurately; the introduction of the volume percentage and constant-pressure specific heat capacity of each component enables the enthalpy calculation to take into account the difference in the contribution of different components to energy; at the same time, distinguishing the constant-pressure specific heat capacity at the inlet and outlet states can better adapt to the impact of temperature and pressure changes on gas properties that may occur in actual operation;

[0081] Such parameter settings help to improve the accuracy and reliability of the air preheater leakage rate determination method and provide more valuable information for equipment operation monitoring, maintenance and optimization.

[0082] In order to further optimize the above embodiment, the volume percentage of each component in the inlet and outlet flue gas is the volume ratio of each component gas in the inlet and outlet flue gas per unit volume, which is used to reflect the relative content of each component gas in the flue gas entering or discharged from the air preheater;

[0083] The type of each component gas is preset, and the flue gas is tested by a flue gas analyzer installed at the inlet and outlet of the air preheater to obtain the volume percentage of each component in the inlet and outlet flue gas.

[0084] It should be noted that clarifying the definition of the volume percentage of each component in the inlet and outlet flue gas will help to understand and use these parameters more accurately; defining it as the volume ratio of each component gas in a unit volume can intuitively reflect the relative content of different components in the flue gas, and provide an important basis for analyzing the combustion process, chemical reaction and energy transfer in the air preheater;

[0085] By presetting the type of each component gas, the appropriate detection method and equipment can be selected in a targeted manner; the flue gas analyzer installed at the inlet and outlet of the air preheater can monitor the changes of each component in the flue gas in real time, providing a timely and reliable data source for the accurate calculation of the air leakage rate; this method can quickly respond to changes in the operating status of the air preheater, helping to promptly discover potential problems and take corresponding measures;

[0086] In addition, the volume percentage of each component obtained by the flue gas analyzer can also be combined with other parameters for more in-depth data analysis and performance evaluation; for example, it can be combined with parameters such as temperature and pressure to further study the thermal efficiency, energy loss and pollutant emissions of the air preheater, providing more comprehensive guidance for optimizing the design and operation of the air preheater.

[0087] In order to further optimize the above embodiment, in step 1, the preprocessing process includes: data cleaning, data conversion and data calibration;

[0088] The data cleaning step includes checking the integrity of the data to ensure that all parameters obtained have specific values ​​and no missing items; and removing outliers by setting reasonable ranges or using statistical methods to identify and eliminate obviously unreasonable data points;

[0089] The data conversion step includes unifying the units of temperature and specific heat capacity parameters for use in subsequent enthalpy calculations;

[0090] The data calibration step includes calibrating the acquired parameters based on the errors and drifts of the sensors and flue gas analyzers.

[0091] It should be noted that data cleaning ensures the integrity and reliability of the data, avoiding the erroneous impact of missing items or abnormal values ​​on subsequent calculations; by checking the integrity of the data, problems in the data collection process can be discovered and corrected in a timely manner; removing abnormal values ​​can improve the quality of the data, so that the calculation results can better reflect the actual operating status of the air preheater; the setting of a reasonable range and the use of statistical methods can effectively identify those obviously unreasonable data points and ensure the rationality of the data;

[0092] Data conversion unifies the units of temperature and specific heat capacity parameters, so that the subsequent enthalpy calculation can be accurately calculated; different units may lead to calculation errors, and unified units can eliminate this potential risk and improve the accuracy and consistency of calculations;

[0093] Data calibration takes into account the errors and drifts of sensors and flue gas analyzers, and corrects the acquired parameters. Sensors may experience error accumulation and drift during long-term use. Calibration can improve data accuracy and ensure the accuracy of leakage rate calculations. Parameter calibration can also improve the stability and reliability of the entire method, enabling it to accurately determine the air preheater leakage rate under different operating conditions.

[0094] In order to further optimize the above embodiment, in step 2, the enthalpy value calculation model includes an inlet flue gas enthalpy value model, an outlet flue gas enthalpy value model, an inlet air enthalpy value model, and an outlet air enthalpy value model;

[0095] The inlet flue gas enthalpy model is:

[0096]

[0097] Among them, H in is the inlet flue gas enthalpy, i represents the component type, C p，i，in is the constant pressure specific heat capacity of component i at the inlet state, V i，in is the volume percentage of component i at the inlet state; T in is the inlet flue gas temperature, T ref is the reference temperature, used to determine a relative zero point when calculating enthalpy;

[0098] The outlet flue gas enthalpy model is:

[0099]

[0100] Among them, H out is the outlet flue gas enthalpy value, i represents the component type, C p，i，out is the constant pressure specific heat capacity of component i at the outlet state, V i，out is the volume percentage of component i at the outlet state; T out is the outlet flue gas temperature;

[0101] The inlet air enthalpy model is:

[0102] H ain =C p，air，in *{T ain -T ref}

[0103] Among them, H ain is the inlet air enthalpy, C p，air，in is the constant pressure specific heat capacity of air at the inlet state, T ain is the inlet air temperature;

[0104] The outlet air enthalpy model is:

[0105] Haout =C p，air，out *{T aout -T ref}

[0106] Among them, H aout is the outlet air enthalpy, C p，air，ouy is the constant pressure specific heat capacity of air at the outlet state, T aout is the outlet air temperature;

[0107] Substitute the flue gas and air parameters at the inlet and outlet of the air preheater into the above model, and calculate the inlet flue gas enthalpy H jn , outlet flue gas enthalpy H 0ut , inlet air enthalpy H ajn And the outlet air enthalpy H aout .

[0108] It should be noted that these enthalpy calculation models are accurately constructed for different states (inlet flue gas, outlet flue gas, inlet air, outlet air);

[0109] For the inlet flue gas enthalpy model, the enthalpy of the inlet flue gas can be accurately calculated by comprehensively considering the constant pressure specific heat capacity, volume percentage and the difference between the inlet flue gas temperature and the reference temperature of each component at the inlet state; this reflects the energy state carried by the inlet flue gas, in which the contribution of each component is explicitly included in the calculation, making the calculation result more in line with the actual situation;

[0110] The outlet flue gas enthalpy model similarly considers the constant pressure specific heat capacity, volume percentage and the difference between the outlet flue gas temperature and the reference temperature of each component at the outlet state, providing an accurate calculation method for determining the energy state of the outlet flue gas;

[0111] The inlet air enthalpy model and the outlet air enthalpy model are respectively aimed at the states of the inlet and outlet air, and only consider the constant pressure specific heat capacity of the air under different states and the difference between the air temperature and the reference temperature, which simplifies the calculation while ensuring the accurate calculation of the air enthalpy value.

[0112] By substituting the acquired flue gas and air parameters at the inlet and outlet of the air preheater into these models, accurate enthalpy results can be obtained, providing a reliable data basis for the subsequent calculation of the leakage rate; the construction and application of these models help to improve the accuracy and reliability of the air preheater leakage rate determination method.

[0113] In order to further optimize the above embodiment, in step three, based on the enthalpy values ​​obtained in step two, analysis is performed to calculate and record the current air leakage rate, specifically including:

[0114] The calculated inlet flue gas enthalpy H in , outlet flue gas enthalpy Hout , inlet air enthalpy H ain And the outlet air enthalpy H aout Substitute into the following formula to calculate the current air preheater leakage rate L;

[0115]

[0116] Insert a timestamp into the data attribute of the current air preheater leakage rate L.

[0117] It should be noted that the current air preheater leakage rate is calculated by substituting the inlet flue gas enthalpy value, outlet flue gas enthalpy value, inlet air enthalpy value and outlet air enthalpy value calculated in step 2 into a specific formula. This method is based on the principles of heat balance and mass balance and can more accurately reflect the actual air preheater leakage situation.

[0118] Inserting a timestamp into the data attribute of the air leakage rate is of great significance. On the one hand, the timestamp can clearly record the time point of the air leakage rate calculation, which is convenient for the time series analysis of the operating status of the air preheater. By observing the changes in the air leakage rate at different time points, the abnormal fluctuations in the air leakage rate can be discovered in time, providing a strong basis for equipment maintenance and fault diagnosis. On the other hand, the timestamp also helps to establish a historical database to evaluate and analyze the long-term operating performance of the air preheater. By analyzing the changing trend of the air leakage rate over a period of time, possible problems in the future can be predicted, and corresponding measures can be taken in advance for prevention and optimization, thereby improving the operating reliability and efficiency of the air preheater.

[0119] In order to further optimize the above embodiment, in step four, the leakage rate L of the air preheater with a timestamp is stored in a historical database, and a line graph of the leakage rate changing with time is drawn, and the leakage rate of the air preheater at a future moment is predicted by time series analysis technology; the statistical image and the predicted value are displayed on the terminal device of the manager, and the leakage rate change at the current moment and the future moment is provided to the manager.

[0120] It should be noted that, first of all, the historical database provides a rich data resource for analyzing the long-term operating performance of the air preheater; by statistically analyzing the air leakage rate data in different time periods, we can understand the changing trend of the air preheater leakage situation and judge whether the equipment has a problem of gradual deterioration, so as to take maintenance measures in time and extend the service life of the equipment;

[0121] Drawing a line chart of the air leakage rate over time can intuitively show the dynamic change process of the air leakage rate; managers can see the fluctuation of the air leakage rate at a glance, quickly identify abnormal points and trend changes, and thus conduct more targeted equipment management and decision-making;

[0122] The use of time series analysis technology to predict the air preheater leakage rate at future times provides forward-looking guidance for planning equipment maintenance and operation strategies in advance; managers can reasonably arrange maintenance plans and adjust operating parameters based on the predicted values ​​to avoid equipment failure or performance degradation due to leakage problems, thereby improving equipment reliability and operating efficiency;

[0123] Displaying statistical images and predicted values ​​on the terminal devices of managers realizes timely transmission and visual display of information. Managers can understand the changes in the air leakage rate of the air preheater anytime and anywhere without having to go to the site to check the data in person, which greatly improves the convenience and timeliness of management. At the same time, this also helps managers make correct decisions in a timely manner to ensure the safe and stable operation of the air preheater.

[0124] Example 2

[0125] The embodiment of the present invention provides a system for determining the air preheater leakage rate. Based on the above-mentioned method for determining the air preheater leakage rate, please refer to Figure 2 ,include:

[0126] A data acquisition module is provided at the inlet and outlet of the air preheater to obtain the current flue gas and air parameters at the inlet and outlet of the air preheater;

[0127] The front-end preprocessing module is connected to the data acquisition module and is used to preprocess the flue gas and air parameters at the inlet and outlet of the current air preheater. The preprocessing process includes data cleaning, data conversion and data calibration;

[0128] An enthalpy analysis module is connected to the front-end preprocessing module, and an enthalpy calculation model is established in advance. The enthalpy values ​​corresponding to the flue gas and air parameters at the inlet and outlet of the current air preheater are calculated by the enthalpy calculation model;

[0129] An air leakage rate calculation module, which is connected to the enthalpy value analysis module, performs analysis based on the obtained enthalpy values, calculates and records the current air leakage rate;

[0130] The statistical module is connected to the air leakage rate calculation module and is used to insert a timestamp into the data attribute of the current air preheater's air leakage rate, store it in the historical database, draw a line chart of the change of the air leakage rate over time, and predict the air leakage rate of the air preheater at a future time through the time series analysis technology; display the statistical image and the predicted value on the terminal device of the manager, and provide the manager with the change of the air leakage rate at the current time and the future time;

[0131] It should be noted that the air preheater leakage rate determination system realizes accurate determination, real-time monitoring and future trend prediction of the air preheater leakage rate through the collaborative work of various modules;

[0132] The data acquisition module accurately obtains flue gas and air parameters at the inlet and outlet of the air preheater, providing a basic data source for the entire system; the front-end preprocessing module cleans, converts and calibrates these data to ensure the quality and reliability of the data, laying a solid foundation for subsequent calculations and analysis;

[0133] The enthalpy analysis module uses the pre-established enthalpy calculation model to calculate the enthalpy values ​​of the inlet smoke and air based on the pre-processed data, providing key intermediate results for the calculation of the air leakage rate; the air leakage rate calculation module analyzes these enthalpy values, accurately calculates the current air leakage rate, and records it;

[0134] The statistical module inserts a timestamp into the air leakage rate data and stores it in the historical database, thus realizing long-term tracking and analysis of the air leakage rate. By drawing a line chart and applying time series analysis technology, it can intuitively display the changing trend of the air leakage rate and predict the air leakage rate at future moments, providing an important basis for decision-making for managers. The statistical images and predicted values ​​are displayed on the terminal device, so that managers can understand the operating status of the air preheater at any time and take corresponding measures for equipment management and maintenance in a timely manner.

[0135] The various modules of the entire system cooperate with each other to form a complete air preheater leakage rate determination and monitoring system, which improves the safety, reliability and efficiency of air preheater operation.

[0136] 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 method for determining air preheater leakage rate, characterized in that: include: Step 1: Obtain the current flue gas and air parameters at the inlet and outlet of the air preheater and perform preprocessing; Step 2: Establish an enthalpy calculation model, and calculate the enthalpy values ​​corresponding to the flue gas and air parameters at the inlet and outlet of the current air preheater through the enthalpy calculation model; Step 3: Analyze the enthalpy values ​​obtained in step 2, calculate and record the current air leakage rate; Step 4: Store the current air leakage rate in a historical database and analyze changes in the air leakage rate.

2. The method for determining the air leakage rate of an air preheater according to claim 1, characterized in that: In step 1, the flue gas and air parameters at the inlet and outlet of the air preheater include: air preheater inlet flue gas parameters, air preheater outlet flue gas parameters, air preheater inlet air parameters, and air preheater outlet air parameters; The air preheater inlet flue gas parameters include: inlet flue gas temperature, volume percentage of each component in the inlet flue gas, and constant pressure specific heat capacity of each component in the inlet state; The flue gas parameters at the air preheater outlet include: outlet flue gas temperature, volume percentage of each component in the outlet flue gas, and specific heat capacity of each component at constant pressure in the outlet state; The air preheater inlet air parameters include: inlet air temperature and constant pressure specific heat capacity of air at the inlet state; The air parameters at the air preheater outlet include: outlet air temperature and constant pressure specific heat capacity of the air at the outlet state.

3. A method for determining air preheater leakage rate according to claim 2, characterized in that: The volume percentage of each component in the inlet and outlet flue gas is the volume ratio of each component gas in the inlet and outlet flue gas per unit volume, which is used to reflect the relative content of each component gas in the flue gas entering or discharged from the air preheater; The type of each component gas is preset, and the flue gas is detected by a flue gas analyzer installed at the inlet and outlet of the air preheater to obtain the volume percentage of each component in the inlet and outlet flue gas.

4. A method for determining air preheater leakage rate according to claim 3, characterized in that: In step 1, the preprocessing process includes: data cleaning, data conversion and data calibration; The data cleaning step includes checking the integrity of the data to ensure that each parameter obtained has a specific value and there are no missing items; and removing outliers by setting a reasonable range or using statistical methods to identify and eliminate obviously unreasonable data points; The data conversion step includes unifying the units of temperature and specific heat capacity parameters so as to be used in subsequent enthalpy calculations; The data calibration step includes calibrating the acquired parameters based on the errors and drifts of the sensor and the flue gas analyzer.

5. A method for determining air preheater leakage rate according to claim 4, characterized in that: In step 2, the enthalpy value calculation model includes an inlet flue gas enthalpy value model, an outlet flue gas enthalpy value model, an inlet air enthalpy value model, and an outlet air enthalpy value model; The inlet flue gas enthalpy model is: Among them, H in is the inlet flue gas enthalpy, i represents the component type, C p，i，in is the constant pressure specific heat capacity of component i at the inlet state, V i，in is the volume percentage of component i at the inlet state; T in is the inlet flue gas temperature, T ref is the reference temperature, used to determine a relative zero point when calculating enthalpy; The outlet flue gas enthalpy model is: Among them, H out is the outlet flue gas enthalpy value, i represents the component type, C p，i，out is the constant pressure specific heat capacity of component i at the outlet state, V i，out is the volume percentage of component i at the outlet state; T out is the outlet flue gas temperature; The inlet air enthalpy model is: H ain =C p，air，in *{T ain -T ref } Among them, H ain is the inlet air enthalpy, C p，air，in is the constant pressure specific heat capacity of air at the inlet state, T ain is the inlet air temperature; The outlet air enthalpy model is: H aout =C p，air，out *{T aout -T ref } Among them, H aout is the outlet air enthalpy, C p，air，out is the constant pressure specific heat capacity of air at the outlet state, T aout is the outlet air temperature; Substitute the flue gas and air parameters at the inlet and outlet of the air preheater into the above model, and calculate the inlet flue gas enthalpy H in , outlet flue gas enthalpy H out , inlet air enthalpy H ain And the outlet air enthalpy H aout .

6. A method for determining air preheater leakage rate according to claim 5, characterized in that: In step three, the enthalpy values ​​obtained in step two are analyzed, and the current air leakage rate is calculated and recorded, specifically including: The calculated inlet flue gas enthalpy H in , outlet flue gas enthalpy H out , inlet air enthalpy H ain And the outlet air enthalpy H aout Substitute into the following formula to calculate the current air preheater leakage rate L; Insert a timestamp into the data attribute of the current air preheater leakage rate L.

7. A method for determining air preheater leakage rate according to claim 6, characterized in that: In step four, the air leakage rate L of the air preheater with a timestamp is stored in the historical database, and a line graph of the change in leakage rate over time is drawn, and the air leakage rate of the air preheater at a future moment is predicted by time series analysis technology; the statistical image and the predicted value are displayed on the terminal device of the manager, and the change in leakage rate at the current moment and the future moment is provided to the manager.

8. A system for determining air preheater leakage rate, based on the method of claims 1-7, characterized in that: include: A data acquisition module is provided at the inlet and outlet of the air preheater to obtain the current flue gas and air parameters at the inlet and outlet of the air preheater; A front-end preprocessing module, which is connected to the data acquisition module and is used to preprocess the flue gas and air parameters at the inlet and outlet of the current air preheater, wherein the preprocessing process includes data cleaning, data conversion and data calibration; An enthalpy analysis module is connected to the front-end preprocessing module, and an enthalpy calculation model is pre-established, and the enthalpy values ​​corresponding to the flue gas and air parameters at the inlet and outlet of the current air preheater are calculated by the enthalpy calculation model; An air leakage rate calculation module, which is connected to the enthalpy value analysis module, performs analysis based on the obtained enthalpy values, calculates and records the current air leakage rate; A statistical module is connected to the air leakage rate calculation module and is used to insert a timestamp into the data attribute of the current air preheater's air leakage rate and store it in the historical database. At the same time, a line graph is drawn about the change of the air leakage rate over time, and the air leakage rate of the air preheater at a future moment is predicted by time series analysis technology; the statistical image and the predicted value are displayed on the terminal device of the manager, and the change of the air leakage rate at the current moment and the future moment is provided to the manager.

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