A method and system for rapid cooling of a power plant boiler economizer after a leak

Abstract

The application discloses a power station boiler economizer leakage rapid cooling method and system, and relates to the technical field of boiler safety control, which comprises the following steps: when the boiler is in the state of being closed, an economizer cooling preparation stage is executed; after the preparation stage is completed, a preliminary cooling stage is entered, and a primary air fan is started; the primary air passes through an ammonia injection branch pipe of a pyrolysis furnace and enters a boiler flue, so that the primary air cools the economizer from bottom to top against the flue gas flow direction; after the preliminary cooling stage is completed, an intelligent control cooling stage is entered, the cooling air volume and airflow path are accurately adjusted through an intelligent control algorithm, and urea injection guns are started to wash and assist cooling; the temperature of a leakage area is monitored in real time, and the cooling air volume is automatically adjusted according to the temperature of the leakage area. The method can realize rapid cooling of the economizer area when the economizer leakage occurs, effectively reduces the temperature of the economizer area, maximally shortens the cooling time, and accelerates the maintenance progress of the boiler economizer.

Description

Technical Field

[0001] This invention relates to the field of boiler safety control technology, and in particular to a method and system for rapid cooling after leakage of the economizer in a power plant boiler. Background Technology

[0002] As a crucial component of thermal power units, the operating efficiency of power plant boilers directly impacts the energy utilization rate of the entire power system. In recent years, with the increasing demands for safety, environmental protection, and energy conservation in the power industry, the safety and efficiency of boiler systems have received growing attention. Economizers in power plant boilers, as vital devices used to recover heat from flue gas and improve thermal efficiency, are critical to the overall thermal efficiency and operational safety of the boiler. Traditionally, economizers are cooled using conventional methods, such as natural cooling after shutdown or induced draft fan cooling.

[0003] However, in cases of leaks or other anomalies in the boiler economizer, existing cooling methods generally suffer from slow response, low cooling efficiency, and scale shedding caused by the economizer cooling leading to the cooling of high-temperature heating surfaces. Traditional cooling technologies often rely on conventional cooling methods using boiler induced draft fans for ventilation. After an economizer leak occurs, cooling the economizer will cause the boiler's high-temperature heating surfaces to cool as well. To prevent the high-temperature heating surfaces from cooling down, the economizer cannot be cooled in a timely and precise manner, preventing it from returning to normal operation in the shortest possible time. Existing cooling methods also often neglect real-time monitoring and dynamic adjustment after a leak occurs. Adjustments to cooling airflow and airflow paths usually rely on manual operation, lacking flexible automated control, making it difficult to achieve precise localized cooling, thus affecting the economizer cooling rate and the safety of the boiler system. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a method for rapid cooling after leakage of the economizer in a power plant boiler.

[0006] Existing technologies rely on traditional self-ignition cooling and forced cooling by boiler induced draft fans, which makes it difficult to cool the economizer in a timely and effective manner, resulting in low cooling efficiency, long economizer maintenance time, and may even cause oxide scale peeling damage to the high-temperature heating surfaces of the boiler.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for rapid cooling of an economizer in a power plant boiler after leakage, which includes, when the boiler is in a stale state, first performing an economizer cooling preparation stage.

[0008] After the preparation stage is completed, the initial cooling stage begins: one primary air fan is started; the primary air enters the boiler flue through the ammonia injection branch pipe of the pyrolysis furnace, so that the primary air flows from bottom to top against the flue gas flow to cool the economizer.

[0009] After the initial cooling stage is completed, the intelligent control cooling stage begins: the cooling air volume and airflow path are precisely adjusted through intelligent control algorithms; the urea spray gun flushing water is activated to assist cooling. The system monitors the temperature of the leak area in real time and automatically adjusts the cooling airflow based on the temperature of the leak area.

[0010] As a preferred embodiment of the rapid cooling method for economizer leakage in power plant boilers according to the present invention, the cooling preparation stage includes: closing the SCR (denitrification reactor, hereinafter referred to as SCR) outlet baffle and bypass baffle, opening the SCR inlet baffle, opening the electric door from primary air to the denitrification pyrolysis furnace, shutting down the air preheater, and using the slag remover water seal protection to prevent cooling of the boiler's high-temperature heating surfaces. After the preparation stage is completed, the initial cooling stage begins.

[0011] As a preferred embodiment of the rapid cooling method for economizer leakage in power plant boilers described in this invention, the preliminary cooling stage includes: starting a primary air fan; primary air entering the boiler flue through the ammonia injection branch pipe of the pyrolysis furnace, causing the primary air to flow upwards against the flue gas flow towards the economizer, and exiting through the upper manhole of the economizer, maximizing the contact between the cooling airflow and the heated surface of the economizer for efficient cooling, and then exiting through the manhole of the flue in the upper region of the economizer, while keeping the air preheater in a shut-off state to prevent the residual heat of the flue gas in the air preheater from heating the primary air and to avoid the primary air temperature being too high and affecting the economizer cooling rate; after the preliminary cooling stage is completed, the intelligent control cooling stage is entered, where the cooling air volume and airflow path are precisely adjusted through an intelligent control algorithm; As a preferred embodiment of the rapid cooling method for economizer leakage in power plant boilers according to the present invention, the intelligent control algorithm includes: integrating and optimizing the intelligent control algorithm to automatically generate a cooling strategy based on the boiler's operating status, leakage situation, and temperature data parameters; optimizing the cooling strategy by comprehensively adjusting the cooling air volume, cooling time, and cooling path; and automatically assessing whether the economizer has been cooled to a predetermined temperature (<30℃) by real-time monitoring of temperature changes inside the boiler, ensuring that the temperature in the economizer area of ​​the boiler reaches the standard for personnel to enter. Establish a dynamic model of the boiler system for prediction, and define... State variables at time 1 ,include Boiler temperature at any time Leakage indicators Economizer heating surface temperature distribution ; Control input variables , respectively Cooling airflow at any time baffle position Urea spray gun flushing water flow rate ; The dynamic model state is represented using a discrete-time model, and the current state is output. Time-measurable output variables .

[0012] As a preferred embodiment of the rapid cooling method for the economizer of the power plant boiler after leakage according to the present invention, the precise adjustment of the baffle and airflow path includes collecting real-time data inside the boiler through a real-time temperature sensor and a leakage detection device; the temperature sensor monitors the temperature changes of the boiler and the economizer, and the leakage sensor monitors the leakage status of various parts of the boiler. Extended Kalman filtering is used to process the sensor data to estimate the current boiler status. state of time After the state estimation is completed, the MPC algorithm uses the model predictive control mechanism to adjust the state based on the current state estimate. Input control, predicting the future The behavior of the boiler with the longest step; The dynamic model MPC is used to predict the temperature evolution process of the boiler and economizer, and the temperature change at each prediction step is calculated. Based on the current system state estimate And possible future control inputs, MPC calculates the future Predicted trajectory of the step Adjustments will be made based on future temperature changes; among them Indicates the prediction step size index. ; Based on the predicted state trajectory, optimize the control inputs, including air volume, baffle position, and urea spray gun flushing water flow rate, to achieve the target temperature and minimize energy consumption while meeting system safety constraints. The optimization objective function is to balance temperature control, air volume adjustment, and energy consumption optimization: minimizing temperature deviation, penalties for changes in control input, and deviations between control input and preset values. The constraints during the optimization process include input constraints, state constraints, and path constraints. The control input sequence is obtained by solving the quadratic programming (QP) problem using the MPC method. Execute the control actions in the sequence to make ; This represents the control input parameters at the beginning of the sequence; In the area where the leak occurs, the switch position of the baffle is automatically adjusted based on real-time monitored temperature data to ensure that the cooling airflow covers the economizer heating surface to the maximum extent.

[0013] As a preferred embodiment of the rapid cooling method for economizer leakage in power plant boilers described in this invention, the method of efficiently cooling the economizer using a reverse flue gas flow cooling approach includes: monitoring temperature changes in various areas of the boiler using temperature sensors; detecting leak points in the economizer and boiler in real time using leak sensors; and automatically identifying the specific location of the leak by processing real-time temperature and pressure data using algorithms, and defining it as... Leakage status at any moment ; The boiler state estimate is updated using the Extended Kalman Filter (EKF). This includes temperature Leakage location Economizer heating surface temperature distribution Using leakage monitoring data, the algorithm estimates the impact of leakage on boiler temperature and cooling demand in real time; a bottom-to-top reverse flue gas flow cooling method is adopted, combined with maintaining the water seal of the slag remover, to avoid cooling of the high-temperature zone heating surface; by closing the SCR outlet damper and bypass damper and opening the SCR inlet damper, the primary air flows from bottom to top against the flue gas flow to cool the economizer, and the cooling airflow contacts the economizer heating surface to the maximum extent, so as to quickly reduce the temperature; The cooling path is as follows: primary air fan, pyrolysis furnace, ammonia injection branch pipe, tail flue, economizer, and upper manhole of economizer. Reverse flue gas flow cooling is adopted. When the economizer leaks, the leak location is confirmed to be either side A or side B. If the leak occurs on side A, the upper manhole of the economizer on side A is opened to exhaust the gas, and the electric door from the pyrolysis furnace outlet to the SCR on side A / B is opened to expand the cooling range and ensure the cooling effect of the economizer area on side A. Based on the location of the leak, MPC adjusts the cooling airflow and cooling path using optimization algorithms. When a leak occurs, MPC automatically increases the cooling airflow. In the leak area, the boiler temperature is monitored in real time, and the air volume is dynamically adjusted according to the temperature change. The direction of the cooling air flow is adjusted according to the location of the leak. If a leak occurs on side A, the MPC will automatically increase the air volume of the cooling path on side A.

[0014] As a preferred embodiment of the rapid cooling method for economizer leakage in power plant boilers according to the present invention, the real-time monitoring of the leakage location includes: triggering cooling demand prediction upon leakage detection; and using an MPC algorithm to analyze the impact of the leakage on boiler temperature changes through a prediction model; based on the current leakage location... MPC predicts temperature changes in the leak area based on the size and location of the leak, and calculates future... Temperature changes in the leakage area within the step; MPC optimizes based on multi-objective constraints to obtain control parameters that allow cooling air to flow through the leakage area to the maximum extent, and then precisely adjusts the opening of the SCR inlet damper. And ensure that the airflow does not deviate from the heated surface; automatically adjust the cooling range by calculating the cooling demand of the leakage area; if a leakage occurs on side A, adjust the control input. Increase the cooling airflow on side A, and force open the damper on side A according to the size and temperature of the leak, ensuring that exhaust vents such as manholes can fully ventilate; if a leak occurs on side B, automatically adjust the cooling airflow on side B based on temperature monitoring results. and SCR inlet baffle opening This ensures that the cooling airflow covers the leakage area on side B to the maximum extent. If an infeasible solution is encountered during the MPC optimization process, the system automatically enters a safety mode and implements preset protection measures. In the event of optimization failure, MPC automatically sets the cooling airflow to its maximum value. Ensure that the leak area receives adequate cooling.

[0015] Secondly, the present invention provides a rapid cooling system for economizer leakage in power plant boilers, including a temperature monitoring and status estimation module, which collects boiler internal temperature and leakage data in real time and estimates the current state of the boiler to ensure accurate real-time understanding of boiler temperature and leakage status. The cooling control optimization module uses a model predictive control algorithm to optimize the cooling airflow, baffle position, and urea spray gun flushing water flow rate based on real-time monitoring data. The leak detection and adjustment module monitors the leak location in real time and automatically adjusts the cooling airflow and cooling path according to the leak location and scale; it also optimizes the cooling strategy based on the leak impact predicted by MPC. The feedback module executes the optimized control inputs from the MPC onto the actual equipment, monitors the execution effect, and provides feedback data for further adjustments.

[0016] Thirdly, the present invention provides a computer device including a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program is executed by the processor, it implements any step of the rapid cooling method for a power plant boiler economizer leak as described in the first aspect of the present invention.

[0017] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements any step of the rapid cooling method for a power plant boiler economizer leak as described in the first aspect of the present invention.

[0018] The beneficial effects of this invention are as follows: By monitoring boiler temperature and leak location in real time, it automatically adjusts cooling air volume, airflow path, and cooling time. This allows for a rapid response and effective optimization of the cooling strategy when an economizer leak occurs, minimizing cooling time and preventing over-cooling and equipment damage. Utilizing reverse flue gas flow cooling and urea spray gun flushing water-assisted cooling achieves precise cooling of the leak area, significantly improving cooling efficiency and safety. It can cool most of the economizer's tube panels, employing bottom-to-top reverse flue gas flow cooling, avoiding cooling of high-temperature heating surfaces. This allows for pre-ventilation cooling during boiler shutdown, shortening the cooling time to less than 30 hours. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A flowchart for a rapid cooling method after a leak in the economizer of a power plant boiler.

[0021] Figure 2 Schematic diagram of equipment for rapid cooling method after economizer leakage in power plant boiler Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0025] Reference Figure 1 and Figure 2 As one embodiment of the present invention, this embodiment provides a method for rapid cooling after leakage in the economizer of a power plant boiler, comprising the following steps: S1: When the boiler is in a stalemate, the economizer cooling preparation stage is executed first.

[0026] Furthermore, the economizer cooling preparation stage includes closing the SCR outlet damper and bypass damper, opening the SCR inlet damper, opening the electric door from the primary air to the denitrification pyrolysis furnace, shutting down the air preheater, and using the slag remover water seal protection to prevent cooling of the boiler's high-temperature heating surfaces.

[0027] Monitoring temperature changes within the boiler ensures real-time assessment of temperature trends even when the boiler is shut down. Real-time boiler temperature data is continuously fed back to the control system via temperature sensors. This data is then used for analysis.

[0028] S2: Entering the initial cooling stage.

[0029] In this stage, the system begins preliminary cooling of the economizer and related equipment using a reverse flue gas flow cooling method. The advantage of this method is that it prevents the high-temperature heating surfaces of the boiler from cooling down, thus minimizing cooling time, improving cooling efficiency, and shortening the maintenance period for the boiler economizer.

[0030] It should be noted that the reverse flue gas flow cooling means that the cooling air flows from bottom to top across the economizer's heating surface, allowing the cooling air to cover the economizer's leakage area and rapidly reduce the temperature.

[0031] Further preliminary cooling includes starting a primary air fan, allowing cold primary air to enter the boiler flue through the ammonia injection branch pipe of the pyrolysis furnace, flowing against the flue gas flow direction to cool the economizer; at the same time, the air preheater is kept in a shut-down state to prevent the waste heat of the flue gas in the air preheater from heating the primary air, and to avoid the primary air temperature being too high and affecting the economizer cooling rate.

[0032] The primary air fan starts, providing the necessary cooling air source for the economizer. Cold primary air enters the boiler flue through the ammonia injection branch pipe of the pyrolysis furnace, flowing against the flue gas flow to cool the economizer and rapidly reduce its temperature. This process is particularly important when the boiler is at a high temperature.

[0033] After the primary air blower starts, the cold primary air source immediately enters the pyrolysis furnace, and then enters the flue through the ammonia injection branch pipe after the pyrolysis furnace to cool the economizer. The function of the cooling airflow is to remove heat from the economizer through air convection, thereby rapidly reducing its temperature.

[0034] S3: Intelligent control cooling stage, which precisely adjusts the cooling air volume and airflow path through intelligent control algorithm; starts urea spray gun flushing water to assist cooling; monitors the temperature of the leak area in real time and automatically adjusts the cooling air volume according to the temperature of the leak area.

[0035] The cooling strategy is automatically generated based on the boiler's operating status, leakage situation, and temperature data parameters through integrated optimization of intelligent control algorithms. The cooling strategy is further optimized by comprehensively adjusting the cooling air volume, cooling time, and cooling path.

[0036] Establish a dynamic model of the boiler system for prediction, and define state variables. Including boiler temperature Leakage indicators Economizer heating surface temperature distribution .

[0037] Control input variables These are the cooling air volume and the cooling air volume, respectively. baffle position Urea spray gun flushing water flow rate .

[0038] in, Indicates the boiler at time The temperature inside the boiler. This is the core state variable of the system, used to measure the boiler's operating temperature. Indicates at time Leakage status indicator. Values ​​are 0 or 1; This indicates that there are no leaks in the boiler system; This indicates a leak in the boiler system, and the leak location could be on side A or side B. This indicates the temperature distribution on the economizer's heating surface at time [time value missing]. The economizer heating surface temperature. For simplicity, it is usually represented as a one-dimensional value, describing the temperature state of different regions inside the economizer. This variable helps to assess the economizer's cooling performance and ensure that the heating surfaces are not overheated or undercooled.

[0039] Control input The control inputs are the operating parameters used to control the boiler system. These parameters are dynamically adjusted by the MPC control algorithm to ensure the optimal operating state of the system. Indicates the cooling airflow at any given time. The amount of cooling airflow is typically controlled by the flow rate of the primary air fan. Its value ranges from 0 to 1. This indicates that there is no airflow input; This indicates the maximum airflow input, meaning the fan operates at its maximum flow rate. Indicates the degree of opening and closing of the baffle at time [time]. The baffle control value at that time. The baffle is used to control the path and flow rate of the cooling airflow, and its value ranges from 0 to 1; This indicates that the baffle is fully closed; This indicates that the baffle is fully open. This indicates the urea spray gun flushing water flow rate at any given time. The flow rate of the urea spray gun flushing water is used for auxiliary cooling. The magnitude of this flow rate determines the cooling effect of the spray gun, and its value ranges from 0 to 1. This indicates that the urea spray gun flushing water is not working; This indicates that the urea spray gun flushing water is operating at maximum flow rate to enhance the cooling effect.

[0040] The specific implementation process of the improved MPC is as follows: The MPC model needs to accurately model the dynamic behavior of the boiler, including variables such as boiler temperature, leakage, and cooling airflow. The system modeling process is based on the original model, with the addition of real-time monitoring and optimized control.

[0041] State variables The formula is expressed as: in, This indicates the boiler temperature. Indicates the leakage index (side A or side B). This indicates the temperature distribution on the economizer's heating surface.

[0042] Control input The formula is expressed as: in, This indicates the cooling air volume (primary fan flow rate). Indicates the degree of baffle opening (controls the airflow path). This indicates the flow rate of the urea spray gun flushing water.

[0043] The mathematical formula for the dynamic model can be expressed as: in, and These are the system state transition matrix and the input matrix, respectively. This indicates external disturbances, such as heat accumulation in a smoldering furnace.

[0044] The output is: The temperature of the boiler is represented by a discrete-time model, and the output is... . The output matrix represents the system state vector. How does it affect output? .

[0045] Furthermore, precise adjustment of the baffles and airflow paths includes collecting real-time data from inside the boiler using real-time temperature sensors and leak detection equipment; the temperature sensors monitor temperature changes in the boiler and economizer, while the leak sensors monitor the leakage status of various parts of the boiler.

[0046] The system employs intelligent control algorithms to monitor the economizer's temperature and cooling requirements in real time, automatically adjusting the opening and closing states of the SCR outlet baffle, bypass baffle, and inlet baffle. These baffles control the path of the cooling airflow, ensuring that the airflow effectively traverses the entire economizer and minimizes its temperature. The intelligent control system precisely adjusts the baffle opening and closing degree through real-time analysis of temperature sensor data, making the airflow path more aligned with actual cooling needs.

[0047] The airflow path is optimized; the control system adjusts the airflow path in real time based on temperature monitoring data during each control cycle. First, the SCR outlet damper and bypass damper are closed, while the SCR inlet damper is opened, allowing primary air to flow upwards against the flue gas flow towards the economizer. This ensures sufficient contact between the cooling airflow and the economizer's heating surfaces, carrying away more heat.

[0048] The optimization problem is formulated by incorporating the following objective function and constraints into the improved MPC, optimizing the cooling strategy. The optimization formula is expressed as follows: Predicted steps This corresponds to the entire process from precooling to reverse flue gas flow cooling. Control steps. Control the optimization step size to balance computation and response speed.

[0049] in, It is the predicted output, representing the value at time [time]. Based on the current state For the future The predicted results output by the system at any given time. In this context, it is usually the boiler temperature or related cooling variables (such as the economizer temperature). This is the reference trajectory, representing the desired target output value, such as the target temperature. In MPC control, the reference trajectory is typically the temperature setpoint (e.g., 50°C), which is compared with the actual output to determine the optimization target. The weighted quadratic norm is used to weight the output error, and the weight matrix Q is used to set the degree of importance given to different errors. For example, for the penalty of temperature error, Q will give higher weight to the temperature component to ensure that temperature control has a higher priority.

[0050] This is the change in control input, representing the change in control input from the current time to a future time k+i. This term is used to penalize excessively large changes in control input, ensuring the smoothness and energy efficiency of the control strategy.

[0051] This represents the weighted quadratic norm, which weights the changes in the control input. The weight matrix R is used to set the degree of penalty for changes in the control input, preventing excessive fluctuations and energy waste.

[0052] It is the predicted value of the control input, representing the value at time 10:00. Control input at multiple time points. Typically, MPC only executes the prediction of the first control input in each cycle, but the optimization problem predicts the values ​​of the control input at multiple time points. This represents the nominal input, typically the desired control input, which indicates the ideal operating state of the system. For example, assuming a boiler operates at a moderate cooling airflow rate under normal conditions, this is typically... (Medium cooling strategy).

[0053] This represents a penalty term for deviations of the control input from the nominal input. It is calculated using the weighted norm. This limits the variation of the control input, making the control input as close as possible to the desired nominal input, and avoiding excessively large or unstable control inputs.

[0054] Predicted steps and control steps , This refers to the prediction step count, which represents the time step size for MPC predictions. It indicates that MPC predicts the next 10 time steps at each moment, covering the entire process from precooling to reverse flue gas flow cooling. A larger prediction step count allows the system to predict longer timeframes, but also increases computational complexity. The control steps represent the number of control input steps that need to be calculated during each optimization. The control steps determine how many future time steps of control input are considered in each optimization calculation. Typically, the control steps are smaller than the prediction steps, meaning optimization only needs to be performed on a few future time steps before executing the first control input. The control steps balance computational complexity and response speed.

[0055] Multiple constraints are added to the MPC control to ensure the safety and efficiency of the cooling process.

[0056] Input constraints, (Airflow limit). (SCR inlet baffle opening). (Upper limit of urea spray gun flushing water flow rate).

[0057] State constraints, (High temperature protection). (Avoid excessive cold, water seal protection).

[0058] Leakage constraint: If leakage occurs on side A, forced... (Open the manhole door on side A). The reverse flue gas flow direction is constrained by the cooling path. (Ensure bottom-to-top cooling coverage).

[0059] Extended Kalman filtering is used to process the sensor data to estimate the current state of the boiler. After state estimation is completed, the MPC algorithm uses the model predictive control mechanism to adjust the current estimated state. Input control, predicting the future The behavior of the boiler with the step length.

[0060] The dynamic model MPC is used to predict the temperature evolution of the boiler and economizer, and the temperature change at each prediction step is calculated.

[0061] Based on the current system state estimate And possible future control inputs, MPC calculates the future Predicted trajectory of the step Adjustments will be made in response to future temperature changes.

[0062] Based on the predicted state trajectory, optimize the control inputs, including air volume, baffle position, and urea spray gun flushing water flow rate, to achieve the target temperature and minimize energy consumption while meeting system safety constraints. The optimization objective function is to balance temperature control, air volume adjustment, and energy consumption optimization: minimizing temperature deviation, penalties for changes in control input, and deviations between the control input and preset values.

[0063] The constraints during the optimization process include input constraints, state constraints, and path constraints.

[0064] The control input sequence is obtained by solving the quadratic programming (QP) problem using the MPC method. Execute the control actions in the sequence to make .

[0065] Based on real-time temperature monitoring data, the switch position of the baffle is automatically adjusted to ensure that the cooling airflow covers the economizer heating surface to the maximum extent; in areas where leaks occur, equipment damage caused by uneven cooling is avoided.

[0066] It should be noted that throughout the process, MPC and intelligent control algorithms continuously optimize the system control strategy through a feedback mechanism. After each control action is executed, temperature data is fed back to the system. Based on this data, the system optimizes the control input and prepares for the next cooling operation. As the cooling air passes through the economizer and carries away heat, the temperature data is transmitted back to the control system in real time. The system adjusts the airflow, baffles, and airflow path based on the feedback information to ensure that subsequent cooling operations achieve the best results. Each optimization cycle provides new control inputs for the next cooling operation, thus forming a closed-loop feedback control system.

[0067] like Figure 2 As shown, further, the efficient cooling of the economizer using a reverse flue gas flow cooling method includes monitoring temperature changes in various areas of the boiler through temperature sensors, and detecting leaks in the economizer or boiler in real time using leak sensors; the control system processes real-time temperature and pressure data through algorithms to automatically identify the specific location of the leak and treat it as an important state variable. This indicates a leakage state.

[0068] State estimation and updating: The boiler state estimate is updated using an extended Kalman filter (EKF). This includes temperature Leakage location Economizer heating surface temperature distribution Using leakage monitoring data, the algorithm estimates the impact of leakage on boiler temperature and cooling demand in real time and makes adjustments accordingly; a bottom-up reverse flue gas flow cooling method is adopted, combined with maintaining the water seal of the slag remover, to avoid cooling of the high-temperature zone heating surface; by closing the SCR outlet damper and bypass damper and opening the SCR inlet damper, the primary air flows from bottom to top against the flue gas flow to cool the economizer, and the cooling airflow contacts the economizer heating surface to the maximum extent, so as to quickly reduce the temperature.

[0069] The cooling path is: primary air fan, pyrolysis furnace, ammonia injection branch pipe, tail flue, economizer, and upper manhole of economizer. Reverse flue gas flow cooling is adopted. When the economizer leaks, the leak location is confirmed to be side A or side B. If the leak occurs on side A, the upper manhole of the economizer on side A is opened to exhaust the gas, and the electric door from the pyrolysis furnace outlet to the SCR on side A / B is opened to expand the cooling range and ensure the cooling effect of the economizer area on side A.

[0070] Based on the location of the leak, MPC adjusts the cooling airflow and cooling path using optimization algorithms. When a leak occurs, MPC automatically increases the cooling airflow. In the leak area; by monitoring the boiler temperature in real time, the air volume is dynamically adjusted according to the temperature change, and the direction of the cooling air flow is adjusted according to the location of the leak; if a leak occurs on side A, the MPC will automatically increase the air volume of the cooling path on side A, and the cooling air can effectively cover the leak area by using the reverse flue gas flow cooling method.

[0071] During cooling in the high-temperature zone, the water seal protection system of the slag remover plays a crucial role. The water seal prevents direct cooling of the heated surfaces in the high-temperature zone during the economizer cooling process, preventing thermal stress caused by sudden temperature drops and thus avoiding equipment damage. During the cooling process, the MPC algorithm monitors the economizer temperature in real time. and boiler temperature The water seal protection of the slag remover is automatically adjusted according to cooling requirements.

[0072] Constraints of water seal protection Maintain within a certain temperature range (e.g.) This prevents excessive cooling that could damage high-temperature areas. If the temperature is too low, the system will reduce the cooling intensity by adjusting the cooling airflow and baffle position to ensure that the temperature of high-temperature areas does not drop too quickly.

[0073] It should be noted that MPC not only optimizes the cooling path but also ensures that the water seal protection system works effectively in conjunction with the cooling control strategy by precisely adjusting the cooling intensity. If the temperature in a certain area approaches the minimum temperature requirement for water seal protection, MPC will reduce the airflow and adjust the SCR inlet damper opening to prevent overcooling and ensure the stability of the water seal area.

[0074] Furthermore, the MPC improvement process involves real-time monitoring of the leak location and automatic adjustment of cooling airflow and cooling range based on the leak area.

[0075] To address the need for real-time leak location monitoring and automatic adjustment of cooling airflow and cooling range based on the leak area, real-time data collection and leak location identification are implemented. During boiler cooling, real-time sensors continuously monitor parameters such as boiler internal temperature, leak location, and cooling airflow. This data is transmitted to the control system, serving as the basis for subsequent optimization decisions.

[0076] Temperature sensors monitor temperature changes in various areas of the boiler, and leak sensors (such as pressure sensors, flow sensors, or acoustic sensors) are used to detect leaks in the economizer or boiler in real time. Leak location calibration: The control system processes real-time data such as temperature and pressure using algorithms to automatically identify the specific location of the leak (side A or side B) and treats it as an important state variable. This indicates a leakage state.

[0077] State estimation and update: The system updates the boiler's state estimate using an extended Kalman filter (EKF) or other filtering algorithms. This includes temperature Leakage location Economizer heating surface temperature distribution Using leak monitoring data, the algorithm estimates the impact of leaks on boiler temperature and cooling requirements in real time and makes adjustments accordingly.

[0078] Leak-induced cooling demand prediction: Once a leak is detected, the MPC algorithm analyzes the impact of the leak on boiler temperature changes using a predictive model. By predicting future temperature trajectories, MPC can estimate the cooling demand in the leak area and dynamically adjust the cooling strategy. Predictive control and cooling optimization: based on the current leak location. MPC will calculate future... Potential temperature changes in the leak area. Predicted temperature changes in the leak area: For areas where leaks occur, MPC will prioritize cooling, optimize cooling airflow and cooling time to reduce the temperature in the leak area to a safe range as quickly as possible.

[0079] Based on the location of the leak, MPC uses optimization algorithms to adjust the cooling airflow and cooling path to ensure that the temperature in the leak area drops to a safe level in the shortest possible time. Key steps include automatically adjusting the cooling airflow; when a leak occurs, MPC automatically increases the cooling airflow. In the leak area, the system dynamically adjusts the airflow based on real-time boiler temperature changes to ensure adequate cooling of the leak area.

[0080] MPC adjusts the direction of cooling airflow based on the location of the leak. For example, if a leak occurs on side A, MPC will automatically increase the airflow in the cooling path on side A, using a reverse flue gas flow cooling method to ensure that the cooling air effectively covers the leak area.

[0081] Baffle adjustment, by precisely adjusting the opening of the SCR inlet baffle. The MPC ensures that cooling airflow reaches the leak area to the maximum extent and that the airflow does not deviate from the heated surface. For leak areas, the MPC may force the opening of relevant baffles (such as the A-side baffle) to enhance the cooling effect. By optimizing the control of baffles, airflow, and cooling path, the MPC ensures that the cooling airflow covers the entire economizer heated surface from bottom to top. For leak areas, the system increases the airflow and adjusts the opening of the SCR inlet baffle to ensure that the airflow covers the leak area comprehensively and evenly.

[0082] The MPC dynamically adjusts the cooling range of the leak area by calculating the cooling requirements of that area. For example, if a leak occurs on side A, the system adjusts the control input accordingly. Increase the cooling airflow on side A, and simultaneously force open the baffle on side A based on the scale and temperature of the leak, ensuring that exhaust vents such as manholes can fully ventilate. If a leak occurs on side B, the system will automatically adjust the cooling airflow on side B and the opening of the SCR inlet baffle based on temperature monitoring results, ensuring that the cooling airflow covers the leak area on side B to the maximum extent.

[0083] For efficient cooling in the event of a leak, the MPC dynamically adjusts the cooling path (e.g., increasing airflow or adjusting baffle positions) to ensure efficient cooling of the leak area. Furthermore, the system automatically calculates and executes a reverse flue gas flow cooling strategy to ensure that cooling air passes through the economizer from bottom to top, preventing over-cooling and uneven temperature distribution.

[0084] An anomaly detection and rollback mechanism is implemented. If an infeasible solution is encountered during MPC optimization (e.g., insufficient cooling airflow or temperature control exceeding the safe range), the system will automatically enter a safe mode and implement preset protection measures, such as maximum airflow control, to ensure system safety. The system will then roll back to the safe mode; for example, if the optimization solution fails, MPC can automatically set the cooling airflow to its maximum value. This ensures that the leak area is adequately cooled to prevent the temperature from rising to dangerous levels.

[0085] Dynamic adjustment and rolling optimization: MPC's optimized control features a rolling update mechanism. After each execution, the system adjusts the control strategy based on new temperature data and leakage status feedback. Rolling optimization ensures that each control cycle is optimized based on the latest system status. The system dynamically adjusts control inputs such as cooling airflow, SCR inlet damper opening, and spray gun flow rate based on new leakage locations and temperature data, ensuring the cooling process is always in an optimal state. The control actions and feedback information of each cycle affect the optimization target of the next cycle, forming a closed-loop control system. By monitoring boiler temperature changes in real time, it automatically assesses whether the economizer has cooled to the predetermined temperature (<30℃), ensuring that the economizer area temperature meets the standard for personnel access.

[0086] It should be noted that, through the improved MPC control algorithm, leak monitoring and response during the boiler cooling process can achieve precise and efficient control. When a leak is detected, the MPC can not only predict the temperature change in the leak area in real time, but also automatically adjust the cooling airflow and cooling path to ensure that the cooling process is efficient, uniform, and meets safety requirements. In addition, the system can also handle sudden abnormal situations, ensuring the safe and stable operation of the system through real-time feedback and rolling optimization.

[0087] This embodiment also provides a rapid cooling system for economizer leaks in power plant boilers, including: The temperature monitoring and status estimation module collects boiler internal temperature and leakage data in real time and estimates the current boiler status, ensuring an accurate real-time understanding of boiler temperature and leakage status.

[0088] The cooling control optimization module uses a model predictive control algorithm to optimize the cooling airflow, baffle position, and urea spray gun flushing water flow rate based on real-time monitoring data.

[0089] The leak monitoring and adjustment module monitors the leak location in real time and automatically adjusts the cooling airflow and cooling path according to the leak location and scale; it also optimizes the cooling strategy based on the leak impact predicted by MPC.

[0090] The feedback module executes the optimized control inputs from the MPC onto the actual equipment, monitors the execution effect, and provides feedback data for further adjustments.

[0091] This embodiment also provides a computer device applicable to the rapid cooling method after a leak in the economizer of a power plant boiler, comprising: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the rapid cooling method after a leak in the economizer of a power plant boiler as proposed in the above embodiment.

[0092] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0093] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements the rapid cooling method for a power plant boiler economizer after leakage, as proposed in the above embodiment. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0094] In summary, this invention achieves the following: When the boiler is in a stalemate, first, an economizer cooling preparation stage is executed. Then, the primary air fan is started, and cold primary air enters the boiler flue through the ammonia injection branch pipe of the pyrolysis furnace. A reverse flue gas flow cooling method is used to efficiently cool the economizer, and the air is then discharged through the manhole in the upper part of the economizer flue. The cooling air volume and airflow path are precisely adjusted through an intelligent control algorithm. Urea spray gun flushing water is activated to assist cooling, combined with the slag remover's water seal protection to prevent cooling of the boiler's high-temperature heating surfaces. The leak location is monitored in real time, and the cooling air volume and cooling range are automatically adjusted according to the leak area. It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for rapid cooling after leakage in the economizer of a power plant boiler, characterized in that: This includes executing the economizer cooling preparation phase when the boiler is in a stalemate. After the preparation stage is completed, the initial cooling stage begins, and one primary air fan is started. The primary air enters the boiler flue through the ammonia injection branch pipe of the pyrolysis furnace, so that the primary air flows from bottom to top against the flue gas flow to cool the economizer. After the initial cooling stage is completed, the intelligent control cooling stage begins. The intelligent control algorithm precisely adjusts the cooling air volume and airflow path, and starts the urea spray gun flushing water to assist cooling. Real-time monitoring of the temperature in the leak area and automatic adjustment of the cooling airflow based on the temperature in the leak area; The cooling preparation stage includes closing the SCR denitrification reactor outlet baffle and bypass baffle, opening the SCR inlet baffle, opening the primary air to the denitrification pyrolysis furnace electric door, shutting down the air preheater, and using the slag remover water seal protection to prevent the boiler's high-temperature heating surface from cooling. After the preparation stage is completed, the initial cooling stage begins.

2. The rapid cooling method for economizer leakage in a power plant boiler as described in claim 1, characterized in that: The initial cooling stage includes starting a primary air fan; primary air enters the boiler flue through the ammonia injection branch pipe of the pyrolysis furnace, causing the primary air to flow upwards against the flue gas flow towards the economizer, and then exits through the upper manhole of the economizer. The cooling airflow maximizes contact with the heat-receiving surface of the economizer, achieving efficient cooling of the economizer, and then exits through the manhole of the upper flue of the economizer. At the same time, the air preheater is kept in a stopped state to prevent the residual heat of the flue gas in the air preheater from heating the primary air and to avoid the primary air temperature being too high, which would affect the cooling rate of the economizer. After the initial cooling stage is completed, the intelligent control cooling stage begins, in which the cooling air volume and airflow path are precisely adjusted through intelligent control algorithms.

3. The rapid cooling method for economizer leakage in a power plant boiler as described in claim 2, characterized in that: The intelligent control algorithm includes: integrating and optimizing the intelligent control algorithm to automatically generate a cooling strategy based on the boiler's operating status, leakage situation, and temperature data parameters; optimizing the cooling strategy by comprehensively adjusting the cooling air volume, cooling time, and cooling path; and automatically assessing whether the economizer has cooled to a predetermined temperature by monitoring the temperature changes inside the boiler in real time, wherein the predetermined temperature is the standard temperature for personnel to enter the economizer area of ​​the boiler. Establish a dynamic model of the boiler system for prediction, and define... State variables at time 1 ,include Boiler flue gas temperature at any time Leakage indicators Economizer heating surface temperature distribution ; Control input variables , respectively Cooling airflow at any time SCR inlet baffle position Urea spray gun flushing water flow rate ; The dynamic model state is represented using a discrete-time model, and the current state is output. Time-measurable output variables .

4. The rapid cooling method for economizer leakage in a power plant boiler as described in claim 3, characterized in that: The precise adjustment of cooling air volume and airflow path includes collecting real-time data inside the boiler through real-time temperature sensors and leak detection equipment; the temperature sensors monitor temperature changes in the boiler and economizer, and the leak sensors monitor the leakage status of various parts of the boiler. Extended Kalman filtering is used to process the sensor data to estimate the current boiler status. state of time After the state estimation is completed, the MPC algorithm uses the model predictive control mechanism to adjust the current state estimate. Input control, predicting the future The behavior of the boiler with the longest step; The dynamic model MPC is used to predict the temperature evolution process of the boiler and economizer, and the temperature change at each prediction step is calculated. Based on the current system state estimate And possible future control inputs, MPC calculates the future Predicted trajectory of the step Adjustments will be made based on future temperature changes; among them Indicates the prediction step size index. ; Based on the predicted state trajectory, optimize the control inputs, including air volume, baffle position, and urea spray gun flushing water flow rate, to achieve the target temperature and minimize energy consumption while meeting system safety constraints. The optimization objective function is to balance temperature control, air volume adjustment, and energy consumption optimization, minimizing temperature deviation, penalties for changes in control input, and deviations between control input and preset values. The constraints during the optimization process include input constraints, state constraints, and path constraints. The control input sequence is obtained by solving the quadratic programming (QP) problem using the MPC method. Execute the control actions in the sequence to make ; This represents the control input parameters at the beginning of the sequence; In the area where the leak occurs, the switch position of the baffle is automatically adjusted based on real-time monitored temperature data to ensure that the cooling airflow covers the economizer heating surface to the maximum extent.

5. The rapid cooling method for economizer leakage in a power plant boiler as described in claim 4, characterized in that: The real-time monitoring of the leak area temperature includes monitoring temperature changes in various areas of the boiler using temperature sensors, and combining this with real-time detection of leak points in the economizer and boiler using leak sensors; processing real-time temperature and pressure data through algorithms to automatically identify the specific location of the leak and define it as... Leakage status at any moment ; The boiler state estimate is updated using the Extended Kalman Filter (EKF). This includes temperature Leakage location Economizer heating surface temperature distribution Using leakage monitoring data, the algorithm estimates the impact of leakage on boiler temperature and cooling demand in real time; adopts bottom-to-top reverse flue gas flow cooling, and maintains the water seal of the slag remover to prevent the heating surface of the boiler's high-temperature zone from being cooled; by closing the SCR outlet damper and bypass damper and opening the SCR inlet damper, the primary air flows from bottom to top against the flue gas flow to cool the economizer, and the cooling airflow contacts the heating surface of the economizer to the maximum extent, so as to quickly reduce the temperature; The cooling path is as follows: primary air fan, pyrolysis furnace, ammonia injection branch pipe, tail flue, economizer, and upper manhole of economizer. Reverse flue gas flow cooling is adopted. When the economizer leaks, the leak location is confirmed to be either side A or side B. If the leak occurs on side A, the upper manhole of the economizer on side A is opened to exhaust the gas, and the electric door from the pyrolysis furnace outlet to the SCR on side A / B is opened to expand the cooling range and ensure the cooling effect of the economizer area on side A. Based on the location of the leak, MPC adjusts the cooling airflow and cooling path using optimization algorithms. When a leak occurs, MPC automatically increases the cooling airflow. In the leakage area; by monitoring the boiler temperature in real time, the air volume is dynamically adjusted according to the temperature change; if a leakage occurs on side A, the MPC automatically increases the air volume of the cooling path on side A.

6. The rapid cooling method for economizer leakage in a power plant boiler as described in claim 5, characterized in that: The automatic adjustment of cooling airflow includes triggering cooling demand prediction upon leak detection, and using an MPC algorithm to analyze the impact of the leak on boiler temperature changes through a prediction model; based on the current leak location... MPC predicts temperature changes in the leak area based on the size and location of the leak, and calculates future... Temperature changes in the leakage area within the step; MPC optimizes based on multi-objective constraints to obtain control parameters that allow cooling air to flow through the leakage area to the maximum extent, and then precisely adjusts the opening of the SCR inlet damper. And ensure that the airflow does not deviate from the heated surface; automatically adjust the cooling range by calculating the cooling demand of the leakage area; if a leakage occurs on side A, adjust the control input. Increase the cooling airflow on side A, and force open the damper on side A according to the size and temperature of the leak, ensuring that exhaust vents such as manholes can fully ventilate; if a leak occurs on side B, automatically adjust the cooling airflow on side B based on temperature monitoring results. and SCR inlet baffle opening This ensures that the cooling airflow covers the leakage area on side B to the maximum extent. If an infeasible solution is encountered during the MPC optimization process, the system automatically enters a safety mode and implements preset protection measures. In the event of optimization failure, MPC automatically sets the cooling airflow to its maximum value. Ensure that the leak area receives adequate cooling.

7. A rapid cooling system for economizer leakage in a power plant boiler, based on the rapid cooling method for economizer leakage in a power plant boiler according to any one of claims 1 to 6, characterized in that: This includes a temperature monitoring and status estimation module, which collects boiler internal temperature and leakage data in real time and estimates the current boiler status to ensure an accurate real-time understanding of boiler temperature and leakage status. The cooling control optimization module uses a model predictive control algorithm to optimize the cooling airflow, baffle position, and urea spray gun flushing water flow rate based on real-time monitoring data. The leak detection and adjustment module monitors the leak location in real time and automatically adjusts the cooling airflow and cooling path according to the leak location and scale; it also optimizes the cooling strategy based on the leak impact predicted by MPC. The feedback module executes the optimized control inputs from the MPC onto the actual equipment, monitors the execution effect, and provides feedback data for further adjustments.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the rapid cooling method for a power plant boiler economizer leak as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the rapid cooling method for a power plant boiler economizer leak as described in any one of claims 1 to 6.

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