A heating furnace waste heat recovery control method and system

Abstract

The application discloses a heating furnace waste heat recovery control method and system, and relates to the technical field of energy-saving control of industrial heating furnaces. The method collects multi-source parameters of a furnace chamber, exhaust smoke, a heat exchange device and an environment, and after data correction and format unification, obtains heat inertia parameters of the waste heat exchange device through the lumped parameter method, and calculates an initial flow adjustment value in combination with a load variation rate. According to double limiting values, the heat exchange state is divided, the flow parameter is dynamically adjusted and closed-loop calibrated, and the medium flow, the valve opening and the reversing interval are adjusted. A distributed storage unit is built to control data, and the parameter recalculation is triggered differently to generate abnormal prompt information. The application quantifies the heat inertia difference, realizes the graded regulation and control of the heat exchange state, solves the problem of the separation of waste heat recovery and furnace temperature control, improves the waste heat recovery efficiency and the equipment operation stability, and is suitable for the waste heat recovery control of various industrial heating furnaces.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery technology, and more specifically, to a method and system for controlling waste heat recovery from a heating furnace. Background Technology

[0002] Industrial heating furnaces, as core thermal equipment in metallurgical rolling, mechanical heat treatment, and forging processes, release only a portion of the heat from fuel combustion during continuous production, which is then used for workpiece heating. A significant amount of high-temperature heat is directly discharged with the flue gas, resulting in waste heat loss typically accounting for 30% to 50% of the furnace's total energy consumption. The level of waste heat recovery directly determines the furnace's energy consumption indicators and operational economy. To reduce flue gas heat loss, the industry commonly employs multi-stage series waste heat exchangers to preheat the combustion air or cooling medium, achieving waste heat recovery through tiered heat utilization. However, in actual continuous production, the furnace's operating load fluctuates frequently due to variations in workpiece loading, rolling rhythm, and fuel supply. This leads to real-time fluctuations in flue gas temperature and flow rate, resulting in continuously changing waste heat exchange conditions. This places extremely high demands on the real-time performance, accuracy, and adaptability of waste heat recovery control.

[0003] Currently, waste heat recovery control in heating furnaces still relies primarily on traditional fixed-parameter control and single-parameter feedback control. This results in a rudimentary control system with low levels of intelligence and numerous technical shortcomings. In actual operation, multi-source monitoring data is susceptible to high temperatures and electromagnetic interference, leading to issues such as data anomalies, missing data, and drift. Existing technologies lack robust data cleaning, anomaly identification, and classification correction mechanisms, resulting in low reliability of control input data and significant control deviations. Furthermore, waste heat exchange devices at different levels exhibit significant differences in thermal inertia due to variations in structural dimensions, medium capacity, and material properties. Existing control methods fail to quantify and identify thermal inertia parameters and do not consider the adjustment lag caused by different thermal response speeds of various devices, easily leading to mismatches in the adjustment actions of heat exchange devices at different levels and fluctuations in waste heat recovery efficiency. In addition, existing control methods generally use a single temperature threshold for on / off regulation, without combining waste heat recovery efficiency and furnace temperature stability to construct a two-dimensional judgment boundary. This makes it impossible to finely classify heat exchange conditions, and it is difficult to balance maximizing waste heat recovery with stable furnace temperature operation. This can easily lead to contradictory problems such as excessive waste heat recovery causing furnace temperature fluctuations and reduced workpiece heating quality, or insufficient waste heat recovery leading to high energy consumption.

[0004] Among the published patent technologies, Chinese patent CN121089516B discloses a method and system for thermal management of a multi-stage heat exchanger for flue gas waste heat recovery. This solution pre-adjusts the flow rate based on the boiler load change rate and the thermal inertia parameters of the heat exchanger, which can solve the dynamic response mismatch problem under sudden load changes in gas-fired boilers to a certain extent. However, this technical solution is designed for gas-fired boilers and is not adapted to the operating conditions of constant temperature control in industrial heating furnaces and workpiece heating quality constraints. It also lacks a coupling mechanism between waste heat exchange regulation and furnace temperature control, making it unsuitable for direct application in heating furnace scenarios. Chinese patent CN121048430B discloses an intelligent control method for waste heat recovery in industrial furnaces, which achieves basic regulation of medium flow rate through flue gas temperature monitoring. However, its control logic is simple, lacks accurate classification of abnormal data, quantifies differences in device thermal inertia, and has no operating condition-based hierarchical control mechanism. Under conditions of frequent load fluctuations, the adjustment accuracy is low and the response is lagging, failing to meet the requirements for refined and stable operation of heating furnaces.

[0005] In summary, existing waste heat recovery control technologies and publicly available patented solutions for heating furnaces have not yet formed a complete control system encompassing standardized data processing, quantitative identification of thermal inertia, tiered judgment of operating conditions, multi-parameter closed-loop calibration, zoned data management and control, and tiered response to anomalies. This system cannot meet the operational requirements of heating furnaces, which involve variable loads, strong coupling, and high stability. It is difficult to simultaneously achieve efficient waste heat recovery and stable furnace operation, which has become a key technological bottleneck restricting energy conservation, consumption reduction, and efficiency improvement in heating furnaces. Summary of the Invention

[0006] To address the existing technical problems, this invention provides a method for controlling waste heat recovery in a heating furnace, comprising the following steps: Collect furnace temperature parameters, flue gas parameters, waste heat exchanger operating parameters, and environmental parameters of the heating furnace, and perform data correction and format unification processing on the collected parameters. Identify the thermal inertia parameters of each stage of waste heat exchange device, and calculate the initial adjustment value of the cooling medium flow rate corresponding to each stage of waste heat exchange device in combination with the load change rate of the heating furnace. Based on the waste heat recovery efficiency limit and the furnace temperature fluctuation limit, the heat exchange state of the heating furnace is divided into intervals; Based on the divided heat exchange state, the initial adjustment value of the cooling medium flow rate is dynamically adjusted, and numerical calibration is completed in combination with real-time operating parameters. Adjust the cooling medium flow rate, pipeline valve opening, and medium reversal interval of the waste heat exchange device according to the calibrated values. Construct a distributed data storage unit to store the entire process operation parameters and adjustment records of the heating furnace, and configure hierarchical data access rules; The system continuously collects real-time operating parameters and updates the stored data. It recalculates parameters based on the heat exchange status, identifies abnormal parameters, and generates graded prompts.

[0007] Furthermore, parameters such as furnace temperature, flue gas parameters, waste heat exchanger operating parameters, and environmental parameters are collected. Data correction and format standardization are performed on the collected parameters, specifically including: The following parameters are collected as basic parameters: furnace center temperature, temperature difference between inside and outside the furnace, flue gas temperature, flue gas flow rate, inlet and outlet temperatures of cooling medium, flow rate of cooling medium, ambient temperature, and ambient humidity. Remove discrete outlier data from the basic parameters, standardize the unit format of all parameters, and fill in the missing time series data; Distinguish between parameter anomaly types, perform corresponding correction processing on different types of abnormal parameters, and form a unified format of running parameters.

[0008] Furthermore, the thermal inertia parameters of each stage of waste heat exchanger are identified, and combined with the rate of change of the furnace load, the initial adjustment values ​​of the cooling medium flow rate corresponding to each stage of waste heat exchanger are calculated, specifically including: Based on the structural parameters of the waste heat exchange device and the physical properties of the cooling medium, the thermal response time constants of each stage of the waste heat exchange device are obtained. Calculate the real-time load variation rate of the heating furnace and determine the baseline adjustment value of the cooling medium flow rate; The proportional coefficients of each stage of the waste heat exchanger are calculated based on the thermal response time constant, and the proportional coefficients are positively correlated with the thermal response time constant. The initial adjustment value of the cooling medium flow rate is obtained by performing numerical calculations using the flow rate reference adjustment value and the proportional coefficient.

[0009] Furthermore, based on the waste heat recovery efficiency limit and the furnace temperature fluctuation limit, the heat exchange state of the heating furnace is divided into intervals, specifically including: Retrieve the rated technical parameters of the heating furnace to determine the limit values ​​for waste heat recovery efficiency and furnace temperature fluctuation. By combining historical operational data, the two sets of limit values ​​are iteratively calibrated to determine a fixed judgment boundary; Based on fixed judgment boundaries, the heat exchange state of the heating furnace is divided into stable heat exchange state, transitional heat exchange state, and abnormal heat exchange state.

[0010] Furthermore, based on the divided heat exchange state, the initial adjustment value of the cooling medium flow rate is dynamically adjusted, and numerical calibration is completed in conjunction with real-time operating parameters, specifically including: For both transitional and abnormal heat transfer states, the heat transfer characteristics and heat transfer coefficient variation characteristics of each stage of the waste heat exchange device are obtained. The initial adjustment value of the cooling medium flow rate is adjusted based on two sets of characteristic parameters, reducing the flow rate adjustment range of the device with a low thermal response time constant and expanding the flow rate adjustment range of the device with a high thermal response time constant. Collect the outlet temperature and furnace temperature parameters of the waste heat exchanger, and perform closed-loop calibration on the adjusted flow rate value.

[0011] Furthermore, based on the calibrated values, adjust the cooling medium flow rate, pipeline valve opening, and medium reversal interval of the waste heat exchange device, specifically including: The calibrated values ​​are converted into electrical control signals, which are then used to adjust the flow rate of the cooling medium via a frequency converter. The opening range of the valves in the waste heat exchanger pipeline is adjusted by an electric actuator. Adjust the reversal interval of the cooling medium in the waste heat exchange device according to the frequency of load changes in the heating furnace.

[0012] Furthermore, a distributed data storage unit is constructed to store the entire process operation parameters and adjustment records of the heating furnace, and hierarchical data access rules are configured, specifically including: Each heat exchange zone of the heating furnace is equipped with an independent encrypted data storage unit. Set up three levels of data access permissions to define the data read and write scope for different personnel; Summarize all abnormal parameters across the partition and complete the data synchronization update between each storage unit.

[0013] Furthermore, real-time operating parameters are collected cyclically and stored data is updated. Parameters are recalculated based on heat exchange status triggers, and abnormal parameters are identified and graded alerts are generated. Specifically, this includes: Configure corresponding data acquisition cycles for different heat exchange states: use a long acquisition cycle for stable heat exchange states and a short acquisition cycle for abnormal heat exchange states. Identify abnormal parameters such as excessive exhaust temperature, excessive furnace temperature difference, and interruption of cooling medium flow, and immediately start parameter recalculation; Based on the abnormal magnitude of parameters, four alert levels are defined, and corresponding handling rules are matched and sent to the on-site control terminal.

[0014] Furthermore, the heat transfer coefficient variation characteristic refers to the relationship between the heat transfer coefficients on the flue gas side and the cooling medium side as a function of temperature and flow rate, and the heat transfer characteristic refers to the transient heat conduction relationship between the waste heat exchange devices at each stage.

[0015] A waste heat recovery control system for a heating furnace, used to execute the above-described waste heat recovery control method for a heating furnace, the system comprising: The data acquisition and processing unit is used to collect multi-dimensional operating parameters of the heating furnace and to complete parameter correction, format standardization and anomaly classification processing. The parameter identification and calculation unit is used to identify the thermal inertia parameters of the waste heat exchange device and calculate the initial adjustment value of the cooling medium flow rate in combination with the load change rate. The heat exchange state division unit is used to complete the interval division and boundary calibration of the heat exchange state of the heating furnace based on two sets of limiting values. The parameter dynamic calibration unit is used to adjust the flow rate value according to the heat exchange status and complete the closed-loop calibration in combination with real-time parameters. The actuator control unit is used to output control signals to regulate the flow rate of cooling medium, valve opening and medium reversal interval; Distributed storage units are used to partition and encrypt operational data, configure access permissions, and complete cross-unit data synchronization. The real-time monitoring and prompting unit is used to continuously update running data, trigger parameter recalculation, identify anomalies, and generate hierarchical prompt information.

[0016] The positive and progressive effects of this invention are as follows: This invention improves data reliability by accurately classifying anomaly types through multi-source parameter standardization and the Apriori association rule algorithm. It quantifies the thermal inertia parameters of the waste heat exchange device using the lumped parameter method and calculates the initial flow adjustment value to adapt to the device's thermal response characteristics. It completes the graded classification of heat exchange status based on dual limit values ​​and achieves closed-loop calibration of flow parameters using incremental PID control. It synchronously adjusts the medium flow rate, valve opening, and reversing interval, balancing waste heat recovery and furnace stability. Simultaneously, it constructs a distributed storage unit to achieve partitioned data management, differentiated trigger parameter recalculation, and graded anomaly alerts. This effectively solves the problems of extensive control, poor adaptability, low data reliability, and delayed response in existing technologies, improving the waste heat recovery efficiency and operational stability of the heating furnace. Attached Figure Description

[0017] Figure 1 is a flowchart of the overall steps of a waste heat recovery control method for a heating furnace. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. (Refer to...) Figure 1 The specific embodiments of the present invention will be described in detail below with reference to the claims of the present invention. These embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0019] This embodiment is applied to a walking beam furnace in the metallurgical industry. The furnace is equipped with three sets of waste heat exchange devices arranged in series: a high-temperature stage, a medium-temperature stage, and a low-temperature stage. The cooling medium is closed-loop softened water. This embodiment addresses the technical deficiencies of existing technologies, such as the lack of standardized processing of multi-source data, the lack of quantification of thermal inertia differences in waste heat exchange devices, the lack of graded determination of heat exchange status, the disconnect between cooling medium adjustment and furnace operation, the lack of zoned control of data storage, and the lack of differentiated response to abnormal operating conditions. It provides a fully implementable waste heat recovery control method for furnaces.

[0020] A method for controlling waste heat recovery in a heating furnace includes the following steps: collecting furnace temperature parameters, flue gas parameters, operating parameters of the waste heat exchanger, and environmental parameters; correcting and unifying the format of the collected parameters; identifying the thermal inertia parameters of each stage of the waste heat exchanger; calculating the initial adjustment value of the cooling medium flow rate corresponding to each stage of the waste heat exchanger based on the furnace load change rate; dividing the furnace heat exchange state into intervals according to the defined heat exchange state; dynamically adjusting the initial adjustment value of the cooling medium flow rate based on the defined heat exchange state, and performing numerical calibration based on real-time operating parameters; adjusting the cooling medium flow rate, pipeline valve opening, and medium reversing interval of the waste heat exchanger according to the calibrated values; constructing a distributed data storage unit to store the furnace's full-process operating parameters and adjustment records, and configuring hierarchical data access rules; cyclically collecting real-time operating parameters and updating the stored data; recalculating parameters based on heat exchange state triggers; identifying abnormal parameters and generating hierarchical prompt information.

[0021] To further clarify, the process involves collecting parameters such as furnace temperature, flue gas parameters, waste heat exchanger operating parameters, and environmental parameters. The collected parameters undergo data correction and format standardization. Specifically, in one example, furnace temperature parameters are collected using K-type armored thermocouples, with the thermocouples positioned at three measuring points each in the furnace center and on the inner wall surface, collecting the furnace center temperature and the temperature difference between the inside and outside of the furnace. Flue gas parameters are collected using integrated temperature, pressure, and flow sensors installed at the outlet of the main flue gas pipe, collecting the flue gas temperature and flow rate. Waste heat exchanger operating parameters are collected using platinum resistance thermometers and electromagnetic flowmeters installed in the inlet and outlet pipelines of each stage of the device, collecting the cooling medium inlet and outlet temperatures and the cooling medium flow rate. Environmental parameters are collected using temperature and humidity sensors installed in unobstructed areas of the heating furnace workshop, collecting ambient temperature and humidity. These parameters serve as the base parameters. In one example, a three-standard-deviation criterion is used to remove discrete outlier data from the basic parameters, filtering out invalid data caused by electromagnetic interference and equipment vibration; a minimum-maximum normalization method is used to unify the dimensional format of all parameters, eliminating dimensional differences between different physical quantities such as temperature and flow rate; linear interpolation is used to complete missing time-series data, ensuring the continuity of parameter time series; and the Apriori association rule mining algorithm is used to distinguish between equipment failure, operating condition fluctuation, and data drift parameter anomaly types. The specific execution process is as follows: First, the time-series outlier parameters are used as input data for the algorithm, and a minimum support threshold and a minimum confidence threshold are set, both of which are preset fixed values; Second, all outlier parameter combinations are traversed, and the support value of each combination is calculated. Combinations with support values ​​greater than or equal to the minimum support threshold are retained, thereby filtering out frequent feature itemsets; The support calculation formula is: Parameter combination support = Total number of occurrences of the parameter combination ÷ The first step is to calculate the total number of occurrences of all abnormal parameters. The second step is to calculate the correlation strength within frequent feature itemsets, which is represented by a confidence score. Frequent feature itemsets with a confidence score greater than or equal to the minimum confidence threshold are retained. The confidence score calculation formula is: Parameter combination confidence score = Number of times two abnormal parameters occur simultaneously ÷ Number of times the preceding abnormal parameter occurs alone. The third step is to determine the trigger source based on the correlation between the confidence score and the abnormal parameters, and classify the abnormality type according to the trigger source. The classification rules are as follows: Single parameter independent abnormality with a confidence score of 0 is classified as data drift anomaly; Multi-parameter linkage anomaly with a confidence score in the median range is classified as operating condition fluctuation anomaly; Fixed parameter continuous abnormality with a confidence score at the maximum value is classified as equipment failure anomaly. Corresponding correction processing is performed for different types of abnormal parameters. Data drift anomalies are replaced by interpolation of adjacent measurement points, operating condition fluctuation anomalies are smoothed using the moving average method, and equipment failure anomalies are marked and replaced by historical averages. Finally, a unified format of operating parameters is formed, which solves the defects of low data reliability and large deviation of control parameters in the existing technology.

[0022] As further explained, identifying the thermal inertia parameters of each stage of waste heat exchange devices, and combining this with the load change rate of the heating furnace, calculates the initial adjustment value of the cooling medium flow rate corresponding to each stage of waste heat exchange devices. Specifically, in one example, based on the heat exchange area, pipe wall thickness structural parameters, and specific heat capacity and density property parameters of the cooling medium, the thermal response time constant of each stage of waste heat exchange devices is obtained through the lumped parameter method. The thermal response time constant is a thermal inertia parameter, and the specific calculation formula and interpretation are as follows: Thermal response time constant = Total heat capacity of the device ÷ Total heat transfer coefficient of the device; where the total heat capacity of the device is the product of the total mass of the metal and the specific heat capacity of the metal, plus the product of the total mass of the cooling medium and the specific heat capacity of the cooling medium; the total heat transfer coefficient of the device is the product of the comprehensive heat transfer coefficient and the effective heat exchange area of ​​the device; the real-time fuel supply of the heating furnace is collected, and the real-time load change rate of the heating furnace is calculated through the first-order differential calculation method. Based on the load change rate and the historical operation mapping table, the benchmark adjustment value of the cooling medium flow rate is determined. The larger the load change rate, the higher the benchmark adjustment value of the flow rate. In one example, the proportional coefficient of each stage of the waste heat exchanger is calculated using a normalized weighted method based on the thermal response time constant. The proportional coefficient is positively correlated with the thermal response time constant. The proportional coefficient of a single stage = thermal response time constant of that stage ÷ sum of thermal response time constants of all stages. The initial adjustment value of the cooling medium flow rate is obtained by multiplying the flow rate reference adjustment value with the proportional coefficient. The calculation formula is as follows: initial adjustment value of flow rate of a single stage = flow rate reference adjustment value × proportional coefficient of the single stage. This step quantifies the thermal inertia difference of the waste heat exchanger, solving the defect in the prior art where the adjustment logic is not adapted to the thermal response characteristics of the device.

[0023] As further explained, the heat exchange state of the heating furnace is divided into intervals based on the waste heat recovery efficiency limit and the furnace temperature fluctuation limit. Specifically, in one example, the rated thermal power and rated technical parameters of the heating furnace, and the rated technical parameters of the designed flue gas temperature are retrieved. The waste heat recovery efficiency limit and the furnace temperature fluctuation limit are determined through heat balance calculation. Historical misjudgment data from the past 30 days are retrieved, and the two sets of limit values ​​are iteratively calibrated using a Bayesian iterative method. The specific process is as follows: First, the initial limit value and historical misjudgment samples are input; second, the probability of misjudgment under the operating condition is calculated, and the limit value boundary is corrected when the misjudgment probability is greater than the preset standard; third, the iteration is repeated until the misjudgment probability is less than or equal to the preset standard to determine the fixed judgment boundary. According to the fixed judgment boundary, the heat exchange state of the heating furnace is divided into stable heat exchange state, transitional heat exchange state, and abnormal heat exchange state. The waste heat recovery efficiency and the furnace temperature both meet the limit value, which is the stable heat exchange state; a single parameter exceeding the limit value is the transitional heat exchange state; and both parameters exceeding the limit value is the abnormal heat exchange state. This replaces the single threshold control mode of the existing technology and solves the defect of insufficient operating condition adaptability.

[0024] As further explained, based on the divided heat exchange states, the initial adjustment value of the cooling medium flow rate is dynamically adjusted, and numerical calibration is completed in conjunction with real-time operating parameters. Specifically, in one example, for the transitional heat exchange state and the abnormal heat exchange state, the heat transfer characteristics and heat transfer coefficient variation characteristics of each stage of the waste heat exchange device are obtained through finite element numerical simulation; the heat transfer coefficient variation characteristics are the relationship between the heat transfer coefficients of the flue gas side and the cooling medium side and the temperature and flow rate, and the heat transfer characteristics are the transient heat conduction relationship between each stage of the waste heat exchange device. In one example, the initial adjustment value of the cooling medium flow rate is adjusted based on two sets of characteristic parameters, reducing the flow rate adjustment range of the device with a low thermal response time constant and expanding the flow rate adjustment range of the device with a high thermal response time constant. The outlet temperature of the waste heat exchanger and the furnace temperature are collected, and an incremental PID control method is used to perform closed-loop calibration on the adjusted flow rate value. The calculation formula and explanation are as follows: Flow rate calibration value = Proportional adjustment amount + Integral adjustment amount + Derivative adjustment amount; where, proportional adjustment amount = Real-time temperature deviation value × Proportional coefficient; Integral adjustment amount = Cumulative temperature deviation value × Integral coefficient; Derivative adjustment amount = Temperature deviation change rate × Derivative coefficient; Real-time temperature deviation value is the difference between the real-time collected temperature and the target temperature; Cumulative temperature deviation value is the sum of deviation values ​​within a continuous sampling period; and the temperature deviation change rate is the ratio of the difference in deviation values ​​between adjacent periods to the sampling period. This addresses the deficiency of the disconnect between waste heat recovery and furnace operation control in existing technologies.

[0025] As further explained, the cooling medium flow rate, pipeline valve opening, and medium reversing interval of the waste heat exchanger are adjusted according to the calibrated values. Specifically, in one example, the calibrated values ​​are converted into standard electrical control signals of 4 to 20 mA, and the cooling medium delivery flow rate is adjusted by a variable frequency water pump; the opening amplitude of the pipeline valves of the waste heat exchanger is adjusted by an electric regulating ball valve; the number of times the heating furnace load changes within 1 hour is counted to determine the load change frequency. The load change frequency is negatively correlated with the medium reversing interval, and the higher the frequency, the shorter the reversing interval. The reversing interval of the cooling medium in the waste heat exchanger is linearly adjusted according to the load change frequency to achieve stable regulation under all operating conditions.

[0026] To further illustrate, a distributed data storage unit is constructed to store the entire process operation parameters and adjustment records of the heating furnace, and hierarchical data access rules are configured. Specifically, in one example, independent encrypted data storage units are set up for the high-temperature heat exchange zone, medium-temperature heat exchange zone, and low-temperature heat exchange zone of the heating furnace based on industrial Ethernet; a role-based access control model is adopted to set up three levels of data access permissions for administrators, maintenance personnel, and field terminals. Administrators have full read and write permissions, maintenance personnel have data reading and parameter modification permissions, and field terminals only have data reading permissions, thus defining the data reading and writing scope for different personnel; and an edge computing gateway is used to aggregate abnormal parameters of the entire partition to complete millisecond-level data synchronization updates between each storage unit, solving the defects of scattered data storage and poor interoperability in existing technologies.

[0027] As further explained, the system continuously collects real-time operating parameters and updates stored data. It recalculates parameters based on heat exchange status triggers, identifies abnormal parameters, and generates tiered alerts. Specifically, in one example, it configures corresponding data acquisition cycles for different heat exchange states: a 60-second long acquisition cycle for stable heat exchange states and a 5-second short acquisition cycle for abnormal heat exchange states. It identifies abnormal parameters such as excessive exhaust temperature, excessive furnace temperature difference, and cooling medium interruption in real time, and immediately initiates the parameter recalculation process. It classifies parameters into four alert levels—Level 1, Level 2, Level 3, and Level 4—based on the magnitude of the abnormality; the greater the abnormality, the higher the alert level. It matches preset handling rules and distributes the alert information and handling rules to the field industrial control terminal and mobile maintenance terminal via the industrial bus, thus addressing the shortcomings of existing technologies such as delayed control response and untimely abnormal handling.

[0028] As further explained, the heat transfer coefficient variation characteristic refers to the relationship between the heat transfer coefficients on the flue gas side and the cooling medium side as a function of temperature and flow rate, and the heat transfer characteristic refers to the transient heat conduction relationship between the waste heat exchange devices at each stage.

[0029] A waste heat recovery control system for a heating furnace, used to execute the aforementioned waste heat recovery control method for a heating furnace, the system comprising: a data acquisition and processing unit for acquiring multi-dimensional operating parameters of the heating furnace and performing parameter correction, format unification, and anomaly classification; a parameter identification and calculation unit for identifying the thermal inertia parameters of the waste heat exchange device and calculating the initial adjustment value of the cooling medium flow rate in conjunction with the load change rate; a heat exchange state division unit for dividing the heat exchange state of the heating furnace into intervals and calibrating the boundaries based on two sets of limit values; a parameter dynamic calibration unit for adjusting the flow rate value according to the heat exchange state and performing closed-loop calibration in conjunction with real-time parameters; an actuator control unit for outputting control signals and adjusting the cooling medium flow rate, valve opening, and medium reversing interval; a distributed storage unit for partitioned encrypted storage of operating parameters, configuring access permissions, and performing cross-unit data synchronization; and a real-time monitoring and prompting unit for cyclically updating operating parameters, triggering parameter recalculation, identifying anomalies, and generating graded prompt information.

[0030] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for controlling waste heat recovery in a heating furnace, characterized in that, Includes the following steps: Collect furnace temperature parameters, flue gas parameters, waste heat exchanger operating parameters, and environmental parameters of the heating furnace, and perform data correction and format unification processing on the collected parameters. Identify the thermal inertia parameters of each stage of waste heat exchange device, and calculate the initial adjustment value of the cooling medium flow rate corresponding to each stage of waste heat exchange device in combination with the load change rate of the heating furnace. Based on the waste heat recovery efficiency limit and the furnace temperature fluctuation limit, the heat exchange state of the heating furnace is divided into intervals; Based on the divided heat exchange state, the initial adjustment value of the cooling medium flow rate is dynamically adjusted, and numerical calibration is completed in combination with real-time operating parameters. Adjust the cooling medium flow rate, pipeline valve opening, and medium reversal interval of the waste heat exchange device according to the calibrated values. Construct a distributed data storage unit to store the entire process operation parameters and adjustment records of the heating furnace, and configure hierarchical data access rules; The system continuously collects real-time operating parameters and updates the stored data. It recalculates parameters based on the heat exchange status, identifies abnormal parameters, and generates graded prompts.

2. The method for controlling waste heat recovery in a heating furnace according to claim 1, characterized in that, Collect furnace temperature parameters, flue gas parameters, waste heat exchanger operating parameters, and environmental parameters of the heating furnace. Perform data correction and format standardization processing on the collected parameters, specifically including: The following parameters are collected as basic parameters: furnace center temperature, temperature difference between inside and outside the furnace, flue gas temperature, flue gas flow rate, inlet and outlet temperatures of cooling medium, flow rate of cooling medium, ambient temperature, and ambient humidity. Remove discrete outlier data from the basic parameters, standardize the unit format of all parameters, and fill in the missing time series data; Distinguish between parameter anomaly types, perform corresponding correction processing on different types of abnormal parameters, and form a unified format of running parameters.

3. The waste heat recovery control method for a heating furnace according to claim 1, characterized in that, Identify the thermal inertia parameters of each stage of waste heat exchanger, and calculate the initial adjustment values ​​of the cooling medium flow rate for each stage of waste heat exchanger based on the furnace load variation rate. Specifically, this includes: Based on the structural parameters of the waste heat exchange device and the physical properties of the cooling medium, the thermal response time constants of each stage of the waste heat exchange device are obtained. Calculate the real-time load variation rate of the heating furnace and determine the baseline adjustment value of the cooling medium flow rate; The proportional coefficients of each stage of the waste heat exchanger are calculated based on the thermal response time constant, and the proportional coefficients are positively correlated with the thermal response time constant. The initial adjustment value of the cooling medium flow rate is obtained by performing numerical calculations using the flow rate reference adjustment value and the proportional coefficient.

4. The waste heat recovery control method for a heating furnace according to claim 1, characterized in that, Based on the waste heat recovery efficiency limit and the furnace temperature fluctuation limit, the heat exchange state of the heating furnace is divided into intervals, specifically including: Retrieve the rated technical parameters of the heating furnace to determine the limit values ​​for waste heat recovery efficiency and furnace temperature fluctuation. By combining historical operational data, the two sets of limit values ​​are iteratively calibrated to determine a fixed judgment boundary; Based on fixed judgment boundaries, the heat exchange state of the heating furnace is divided into stable heat exchange state, transitional heat exchange state, and abnormal heat exchange state.

5. The waste heat recovery control method for a heating furnace according to claim 1, characterized in that, Based on the defined heat exchange state, the initial adjustment value of the cooling medium flow rate is dynamically adjusted, and numerical calibration is completed in conjunction with real-time operating parameters. Specifically, this includes: For both transitional and abnormal heat transfer states, the heat transfer characteristics and heat transfer coefficient variation characteristics of each stage of the waste heat exchange device are obtained. The initial adjustment value of the cooling medium flow rate is adjusted based on two sets of characteristic parameters, reducing the flow rate adjustment range of the device with a low thermal response time constant and expanding the flow rate adjustment range of the device with a high thermal response time constant. Collect the outlet temperature and furnace temperature parameters of the waste heat exchanger, and perform closed-loop calibration on the adjusted flow rate value.

6. The waste heat recovery control method for a heating furnace according to claim 1, characterized in that, Based on the calibrated values, adjust the cooling medium flow rate, pipeline valve opening, and medium reversal interval of the waste heat exchanger, specifically including: The calibrated values ​​are converted into electrical control signals, which are then used to adjust the flow rate of the cooling medium via a frequency converter. The opening range of the valves in the waste heat exchanger pipeline is adjusted by an electric actuator. Adjust the reversal interval of the cooling medium in the waste heat exchange device according to the frequency of load changes in the heating furnace.

7. The method for controlling waste heat recovery in a heating furnace according to claim 1, characterized in that, Construct a distributed data storage unit to store the entire process operation parameters and adjustment records of the heating furnace, and configure hierarchical data access rules, specifically including: Each heat exchange zone of the heating furnace is equipped with an independent encrypted data storage unit. Set up three levels of data access permissions to define the data read and write scope for different personnel; Summarize all abnormal parameters across the partition and complete the data synchronization update between each storage unit.

8. The waste heat recovery control method for a heating furnace according to claim 1, characterized in that, The system continuously collects real-time operating parameters and updates stored data. It recalculates parameters based on heat exchange status triggers, identifies abnormal parameters, and generates tiered alerts, specifically including: Configure corresponding data acquisition cycles for different heat exchange states: use a long acquisition cycle for stable heat exchange states and a short acquisition cycle for abnormal heat exchange states. Identify abnormal parameters such as excessive exhaust temperature, excessive furnace temperature difference, and interruption of cooling medium flow, and immediately start parameter recalculation; Based on the abnormal magnitude of parameters, four alert levels are defined, and corresponding handling rules are matched and sent to the on-site control terminal.

9. The waste heat recovery control method for a heating furnace according to claim 5, characterized in that, The heat transfer coefficient variation characteristic refers to the relationship between the heat transfer coefficients on the flue gas side and the cooling medium side and the temperature and flow rate. The heat transfer characteristic refers to the transient heat conduction relationship between the waste heat exchange devices at each stage.

10. A waste heat recovery control system for a heating furnace, characterized in that, The system is used to implement the waste heat recovery control method for a heating furnace according to any one of claims 1 to 9, the system comprising: The data acquisition and processing unit is used to collect multi-dimensional operating parameters of the heating furnace and to complete parameter correction, format standardization and anomaly classification processing. The parameter identification and calculation unit is used to identify the thermal inertia parameters of the waste heat exchange device and calculate the initial adjustment value of the cooling medium flow rate in combination with the load change rate. The heat exchange state division unit is used to complete the interval division and boundary calibration of the heat exchange state of the heating furnace based on two sets of limiting values. The parameter dynamic calibration unit is used to adjust the flow rate value according to the heat exchange status and complete the closed-loop calibration in combination with real-time parameters. The actuator control unit is used to output control signals to regulate the flow rate of cooling medium, valve opening and medium reversal interval; Distributed storage units are used to partition and encrypt operational data, configure access permissions, and complete cross-unit data synchronization. The real-time monitoring and prompting unit is used to continuously update running data, trigger parameter recalculation, identify anomalies, and generate hierarchical prompt information.

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