A double-zone multi-couple temperature control system for a large gas furnace

Abstract

The application relates to the field of combustion furnaces, and discloses a double-zone multi-temperature-control-system of a large gas furnace, which comprises a second burner, a third burner, a first temperature sensor, a second temperature sensor, a correction temperature sensor and a control system. The control system is configured to calculate a basic combustion control signal of the second burner according to a first deviation, calculate a third deviation based on the temperature detected by the correction temperature sensor and the temperature detected by the first temperature sensor, calculate a combustion limiting ratio of the second burner according to the third deviation, combine the combustion limiting ratio of the second burner with the basic combustion control signal to generate a final combustion control signal of the second burner, and control the combustion of the second burner through the second combustion controller. Through the technical scheme, the temperature difference between the zones is reduced.

Description

Technical Field

[0001] This application relates to the field of combustion furnaces, and more particularly to a dual-zone multi-couple temperature control system for a large gas-fired furnace. Background Technology

[0002] Large direct-fired gas furnaces are commonly used in the heat treatment of large shafts, forgings, cast steel parts, and pressure vessels in industries such as metallurgy, machinery, and chemical equipment. This type of furnace typically cannot be equipped with a stirring fan and must rely on burner airflow to ensure temperature uniformity. Furthermore, due to its large size, uniform temperature control cannot be achieved in a single area; the furnace chamber must be divided into multiple heating zones for control. However, the boundary between two temperature control zones experiences significant temperature fluctuations due to the simultaneous influence of both zones, making it particularly prone to temperature overshoot, which can significantly impact product quality.

[0003] Solving this technical problem is a technical challenge that needs to be overcome by those skilled in the art. Summary of the Invention

[0004] This application provides a dual-zone multi-couple temperature control system for a large gas furnace, which at least partially solves the above-mentioned technical problems.

[0005] To achieve the above objectives, according to a first aspect of this application, a dual-zone multi-couple temperature control system for a large gas-fired furnace is provided, comprising:

[0006] The furnace body has a first heating zone and a second heating zone inside, and a first adjacent area and a second adjacent area are provided between the first heating zone and the second heating zone.

[0007] A second burner is disposed within the first adjacent area; the second burner is connected to a second combustion controller;

[0008] A third burner is disposed in the second adjacent area; the third burner is connected to a third combustion controller;

[0009] The first temperature sensor is used to detect the temperature of the first heating zone;

[0010] The second temperature sensor is used to detect the temperature of the second heating zone;

[0011] A calibration temperature sensor is set at the boundary between the first adjacent region and the second adjacent region to detect the temperature at the boundary.

[0012] The control system is electrically connected to the first temperature sensor, the second temperature sensor, the calibration temperature sensor, the second combustion controller, and the third combustion controller, respectively.

[0013] The control system is configured as follows:

[0014] The basic combustion control signal of the second burner is calculated based on the first deviation; the third deviation is calculated based on the temperature detected by the calibration temperature sensor and the temperature detected by the first temperature sensor; the combustion limitation ratio of the second burner is calculated based on the third deviation; the combustion limitation ratio of the second burner is combined with the basic combustion control signal to generate the final combustion control signal of the second burner, and the combustion of the second burner is controlled by the second combustion controller.

[0015] The basic combustion control signal of the third burner is calculated based on the second deviation; a fourth deviation is calculated based on the temperature detected by the calibration temperature sensor and the temperature detected by the second temperature sensor, and the combustion limitation ratio of the third burner is calculated based on the fourth deviation; the combustion limitation ratio of the third burner is combined with the basic combustion control signal to generate the final combustion control signal of the third burner, and the combustion of the third burner is controlled by the third combustion controller.

[0016] Optionally, the system further includes:

[0017] A first burner is disposed in the first heating zone; the first burner is connected to a first combustion controller;

[0018] A fourth burner is located in the second heating zone; the fourth burner is connected to a fourth combustion controller;

[0019] The control system is also electrically connected to the first combustion controller and the fourth combustion controller;

[0020] The control system is also configured to:

[0021] A first deviation is calculated based on the temperature detected by the first temperature sensor and the set temperature; a combustion control signal for the first burner is calculated based on the first deviation, and the combustion of the first burner is controlled by the first combustion controller;

[0022] The second deviation is calculated based on the temperature detected by the second temperature sensor and the set temperature, and the combustion control signal of the fourth burner is calculated based on the second deviation. The combustion of the fourth burner is controlled by the fourth combustion controller.

[0023] Optionally, the control system uses the following control formula to calculate the final combustion control signals for the second and third burners:

[0024] For the second burner:

[0025] ;

[0026] For the third burner:

[0027] ;

[0028] , These are the final combustion control signals for the second and third burners, respectively.

[0029] The first deviation, This is the second deviation. This is the third deviation. This is the fourth deviation;

[0030] , , These are the proportional gain, integral gain, and derivative gain of the first PID algorithm, respectively.

[0031] , These are the proportional gain and integral gain of the first PI algorithm, respectively.

[0032] , , These are the proportional gain, integral gain, and derivative gain of the second PID algorithm, respectively.

[0033] , These are the proportional gain and integral gain of the second PI algorithm, respectively.

[0034] , These are the first correction factor and the second correction factor, respectively.

[0035] For the first burner: ;

[0036] For the fourth burner: ;

[0037] This is the combustion control signal for the first burner; This is the combustion control signal for the fourth burner.

[0038] Optionally, the control system is further configured to:

[0039] Real-time monitoring of temperature control error, response speed, and stability indicators;

[0040] The corresponding parameter adjustment strategy is selected based on temperature control error, response speed, and stability indicators; the parameter adjustment strategy includes: fast adjustment strategy, fine adjustment strategy, and smooth adjustment strategy.

[0041] Sensitivity analysis is performed on the parameters in the first PID algorithm, the second PID algorithm, the first PI algorithm, and the second PI algorithm. The sensitivity coefficient of each parameter to the control effect is calculated, and the parameters are divided into high-sensitivity parameters, medium-sensitivity parameters, and low-sensitivity parameters according to the sensitivity coefficient.

[0042] Based on the selected parameter adjustment strategy and the results of sensitivity analysis, determine the corresponding parameter adjustment method;

[0043] The magnitude of change of each parameter is obtained based on the response speed, stability index, selected adjustment strategy, and parameter sensitivity level;

[0044] The parameters are adjusted based on the determined parameter adjustment method and the magnitude of the parameter change.

[0045] Optionally, a corresponding parameter adjustment strategy can be selected based on temperature control error, response speed, and stability indicators, including:

[0046] Set a first temperature error threshold T1 and a second temperature error threshold T2, where T2 is less than T1;

[0047] Obtain the absolute value of the current temperature control error;

[0048] Obtain response speed metrics, including rise time and settling time;

[0049] Obtain stability metrics, including overshoot and attenuation ratio;

[0050] The fast adjustment strategy is selected when any of the following conditions are met: the absolute value of the current temperature control error is greater than T1, the adjustment time is greater than the preset adjustment time threshold, the overshoot is greater than the preset overshoot threshold, and the absolute value of the current temperature control error is greater than T2.

[0051] The fine adjustment strategy is selected when all of the following conditions are met simultaneously: the absolute value of the current temperature control error is less than T2, the rise time is less than the preset rise time threshold, the overshoot is less than the preset overshoot threshold, and the attenuation ratio is greater than the preset attenuation ratio threshold.

[0052] In other cases, choose a smooth adjustment strategy.

[0053] Optionally, sensitivity analysis is performed on the parameters in the first PID algorithm, the second PID algorithm, the first PI algorithm, and the second PI algorithm to calculate the sensitivity coefficient of each parameter to the control effect, and the parameters are classified into high-sensitivity parameters, medium-sensitivity parameters, and low-sensitivity parameters according to the sensitivity coefficient, including:

[0054] For each parameter in the first PID algorithm, the second PID algorithm, the first PI algorithm, and the second PI algorithm, apply a numerical change relative to its current value while keeping other parameters constant; calculate the change in system output before and after the parameter change; obtain the sensitivity coefficient based on the ratio of the change in system output to the change in parameters;

[0055] Based on the relative magnitude of the sensitivity coefficient, parameters are classified into high-sensitivity parameters, medium-sensitivity parameters, and low-sensitivity parameters.

[0056] Optionally, based on the selected parameter adjustment strategy and sensitivity analysis results, the corresponding parameter adjustment method is determined, including:

[0057] When a fast adjustment strategy is selected, a large step size dynamic adjustment method is used for high-sensitivity parameters, a medium step size dynamic adjustment method is used for medium-sensitivity parameters, and low-sensitivity parameters are kept fixed.

[0058] When selecting a fine-tuning strategy, a small-step iterative optimization method is used for high-sensitivity parameters, an adaptive step-size adjustment method is used for medium-sensitivity parameters, and low-sensitivity parameters are adjusted according to stability indicators.

[0059] When choosing a smooth adjustment strategy, a gradient descent method under constraints is used for high-sensitivity parameters, a trend correction method based on historical data is used for medium-sensitivity parameters, and the baseline value is kept unchanged for low-sensitivity parameters.

[0060] Among them, the step size of the dynamic adjustment method is proportional to the absolute value of the current temperature control error, the convergence threshold of the iterative optimization method is related to the preset attenuation ratio threshold, and the correction coefficient of the trend correction method is determined by the moving average of the response speed index.

[0061] Optionally, the variation range of each parameter is obtained based on the response speed, stability index, selected adjustment strategy, and parameter sensitivity level, including:

[0062] The basic adjustment range is set based on the parameter sensitivity level; among them, the basic adjustment range of high-sensitivity parameters is set to a value that can quickly improve system performance;

[0063] The basic adjustment range is adjusted according to the system response speed index; when the system response speed is lower than the preset response speed threshold, the basic adjustment range of the high sensitivity parameter is multiplied by the first adjustment coefficient, which is greater than 1; when the system response speed is higher than the preset response speed threshold, the basic adjustment range of all parameters is multiplied by the second adjustment coefficient, which is less than 1.

[0064] The basic adjustment range is adjusted according to the system stability index; when the system stability index is lower than the preset stability threshold, the basic adjustment range of all parameters is multiplied by a third adjustment coefficient, which is less than 1; when the system stability index is higher than the preset stability threshold, the basic adjustment range of the high-sensitivity parameters is multiplied by a fourth adjustment coefficient, which is greater than 1.

[0065] The basic adjustment range is adjusted according to the selected parameter adjustment strategy; when the fast adjustment strategy is selected, the basic adjustment range of all parameters is multiplied by the fifth adjustment coefficient, which is greater than 1; when the fine adjustment strategy is selected, the basic adjustment range of all parameters is multiplied by the sixth adjustment coefficient, which is less than 1; when the smooth adjustment strategy is selected, the basic adjustment range of all parameters remains unchanged.

[0066] The final change range is obtained based on the basic adjustment range, response speed adjustment coefficient, stability adjustment coefficient, and strategy adjustment coefficient.

[0067] Optionally, the control system is further configured to:

[0068] Real-time identification of the furnace's current operating conditions; these operating conditions include the heating phase, the constant temperature phase, and the cooling phase.

[0069] A first weighting coefficient and a second weighting coefficient are generated based on the current operating conditions of the furnace body; the first weighting coefficient and the second weighting coefficient are used to correct the calculation of the third deviation and the fourth deviation, respectively;

[0070] The corrected third bias is obtained by multiplying the first weighting coefficient by the third bias.

[0071] The corrected fourth bias is obtained by multiplying the second weighting coefficient by the fourth bias.

[0072] The corrected third and fourth deviations are used to generate the final combustion control signals for the second and third burners, respectively. When the heating stage or load change stage is identified, the first and second weighting coefficients are set to values ​​less than 1 to reduce the interference of transient temperature fluctuations in the boundary area on the combustion control of adjacent zones. When the constant temperature stage is identified and the temperature fluctuation amplitudes of the first and second heating zones are both less than the preset fluctuation threshold, the first and second weighting coefficients are set to values ​​close to 1 to achieve uniformity of zone boundary temperature.

[0073] In summary, the embodiments of this application, through the above technical solutions, balance the interference between the two main heating areas, avoid temperature overshoot, and solve the technical problem of large temperature fluctuations at the junction.

[0074] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0075] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0076] Figure 1 This is a schematic diagram of a dual-zone multi-couple temperature control system for a large gas furnace provided in an exemplary embodiment of this application. Detailed Implementation

[0077] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0078] This application provides a dual-zone multi-couple temperature control system for a large gas-fired furnace. Please refer to [link / reference]. Figure 1 The dual-zone multi-couple temperature control system for a large gas-fired furnace provided in this application includes:

[0079] A dual-zone multi-couple temperature control system for a large gas-fired furnace, characterized in that it includes:

[0080] The furnace body has a first heating zone and a second heating zone inside, and a first adjacent area and a second adjacent area are provided between the first heating zone and the second heating zone.

[0081] A second burner is disposed within the first adjacent area; the second burner is connected to a second combustion controller;

[0082] A third burner is disposed in the second adjacent area; the third burner is connected to a third combustion controller;

[0083] The first temperature sensor is used to detect the temperature of the first heating zone;

[0084] The second temperature sensor is used to detect the temperature of the second heating zone;

[0085] A calibration temperature sensor is set at the boundary between the first adjacent region and the second adjacent region to detect the temperature at the boundary.

[0086] The control system is electrically connected to the first temperature sensor, the second temperature sensor, the calibration temperature sensor, the second combustion controller, and the third combustion controller, respectively.

[0087] The control system is configured as follows:

[0088] The basic combustion control signal of the second burner is calculated based on the first deviation; the third deviation is calculated based on the temperature detected by the calibration temperature sensor and the temperature detected by the first temperature sensor; the combustion limitation ratio of the second burner is calculated based on the third deviation; the combustion limitation ratio of the second burner is combined with the basic combustion control signal to generate the final combustion control signal of the second burner, and the combustion of the second burner is controlled by the second combustion controller.

[0089] The basic combustion control signal of the third burner is calculated based on the second deviation; a fourth deviation is calculated based on the temperature detected by the calibration temperature sensor and the temperature detected by the second temperature sensor, and the combustion limitation ratio of the third burner is calculated based on the fourth deviation; the combustion limitation ratio of the third burner is combined with the basic combustion control signal to generate the final combustion control signal of the third burner, and the combustion of the third burner is controlled by the third combustion controller.

[0090] Specifically, in existing technologies, large temperature fluctuations occur at the boundary between the two heating zones of a large gas furnace. This is essentially because the temperature interference between the two heating zones cannot be effectively balanced. This invention addresses this by installing a calibration temperature sensor at the boundary to capture temperature changes and convert them into fourth and third deviations. Then, a PI algorithm is used to convert these deviations into combustion limitation ratios, constraining the combustion power of burners in adjacent zones. When the temperature in one heating zone is too high, causing the temperature at the boundary to rise, the combustion limitation ratio automatically decreases, reducing the heating intensity of the burners. The basic combustion control signal is generated based on the temperature deviation of the main heating zone using a PID algorithm, ensuring the basic heating requirements of adjacent zones. This solution balances the interference between the two main heating zones, avoids temperature overshoot, and solves the technical problem of large temperature fluctuations at the boundary, ultimately achieving improved furnace temperature uniformity and enhanced workpiece heat treatment quality.

[0091] In some embodiments, the system further includes:

[0092] A first burner is disposed in the first heating zone; the first burner is connected to a first combustion controller;

[0093] A fourth burner is located in the second heating zone; the fourth burner is connected to a fourth combustion controller;

[0094] The control system is also electrically connected to the first combustion controller and the fourth combustion controller;

[0095] The control system is also configured to:

[0096] A first deviation is calculated based on the temperature detected by the first temperature sensor and the set temperature; a combustion control signal for the first burner is calculated based on the first deviation, and the combustion of the first burner is controlled by the first combustion controller;

[0097] The second deviation is calculated based on the temperature detected by the second temperature sensor and the set temperature, and the combustion control signal of the fourth burner is calculated based on the second deviation. The combustion of the fourth burner is controlled by the fourth combustion controller.

[0098] In some embodiments, the control system is further configured to:

[0099] Real-time monitoring of temperature control error, response speed, and stability indicators;

[0100] The corresponding parameter adjustment strategy is selected based on temperature control error, response speed, and stability indicators; the parameter adjustment strategy includes: fast adjustment strategy, fine adjustment strategy, and smooth adjustment strategy.

[0101] Sensitivity analysis is performed on the parameters in the first PID algorithm, the second PID algorithm, the first PI algorithm, and the second PI algorithm. The sensitivity coefficient of each parameter to the control effect is calculated, and the parameters are divided into high-sensitivity parameters, medium-sensitivity parameters, and low-sensitivity parameters according to the sensitivity coefficient.

[0102] Based on the selected parameter adjustment strategy and the results of sensitivity analysis, determine the corresponding parameter adjustment method;

[0103] The magnitude of change of each parameter is obtained based on the response speed, stability index, selected adjustment strategy, and parameter sensitivity level;

[0104] The parameters are adjusted based on the determined parameter adjustment method and the magnitude of the parameter change.

[0105] Specifically, temperature control error is the difference between the actual measured temperature in the system and the set target temperature;

[0106] Response speed refers to how quickly a system reacts to changes in a set temperature, usually measured by rise time and settling time. Rise time is the time required for the system to reach 63.2% of the new set temperature from a steady state, while settling time is the time required for the system to regain stability near the new set temperature after being disturbed. Stability indicators mainly include overshoot and attenuation ratio. Overshoot is the maximum deviation of the system from the set temperature during the response process, and attenuation ratio is the ratio between two adjacent peak values.

[0107] A fast tuning strategy is a parameter tuning strategy aimed at rapidly improving system performance. It typically uses a large parameter tuning step size and a fast tuning frequency, and is suitable for situations where the system has large deviations or slow responses. A fine-tuning strategy is a parameter tuning strategy aimed at precise control. It typically uses a small parameter tuning step size and a slow tuning frequency, and is suitable for fine-tuning optimization when the system is close to a stable state. A stable tuning strategy is a compromise parameter tuning strategy that balances tuning speed and system stability. It uses a medium-sized tuning step size and is suitable for most normal operating conditions.

[0108] The sensitivity analysis described above refers to a method of identifying key and secondary parameters by analyzing the degree to which changes in system parameters affect the system output. The sensitivity coefficient is a quantitative indicator that measures the degree of impact of parameter changes on system output, defined as the ratio of the change in system output to the change in parameter. A larger sensitivity coefficient indicates a more significant impact of the parameter on system performance. High-sensitivity parameters are those with relatively large sensitivity coefficients; even small changes in these parameters can have a significant impact on system performance, requiring close monitoring and precise adjustment. Medium-sensitivity parameters are those with moderate sensitivity coefficients; these parameters have some impact on system performance, but the impact is not as significant as that of high-sensitivity parameters. Low-sensitivity parameters are those with relatively small sensitivity coefficients; changes in these parameters have a small impact on system performance, and the adjustment precision requirements can be appropriately relaxed.

[0109] Through the above scheme, the system selects an appropriate adjustment strategy based on temperature control error, response speed, and stability indicators, thereby improving temperature uniformity.

[0110] In some embodiments, a corresponding parameter adjustment strategy is selected based on temperature control error, response speed, and stability indicators, including:

[0111] Set a first temperature error threshold T1 and a second temperature error threshold T2, where T2 is less than T1;

[0112] Obtain the absolute value of the current temperature control error;

[0113] Obtain response speed metrics, including rise time and settling time;

[0114] Obtain stability metrics, including overshoot and attenuation ratio;

[0115] The fast adjustment strategy is selected when any of the following conditions are met: the absolute value of the current temperature control error is greater than T1, the adjustment time is greater than the preset adjustment time threshold, the overshoot is greater than the preset overshoot threshold, and the absolute value of the current temperature control error is greater than T2.

[0116] The fine adjustment strategy is selected when all of the following conditions are met simultaneously: the absolute value of the current temperature control error is less than T2, the rise time is less than the preset rise time threshold, the overshoot is less than the preset overshoot threshold, and the attenuation ratio is greater than the preset attenuation ratio threshold.

[0117] In other cases, choose a smooth adjustment strategy.

[0118] Specifically, when the system experiences large deviations or slow response due to sudden load changes or the initial stage of heating, the rapid adjustment strategy can quickly enhance the control strength to shorten the adjustment time; when the system enters the vicinity of steady state and the fluctuations are small, the fine adjustment strategy can suppress residual errors and improve temperature uniformity through small step size optimization; during the transition phase, the smooth strategy avoids oscillations caused by frequent parameter adjustments, thus enhancing the adaptability of the heating furnace under different process stages.

[0119] In some embodiments, sensitivity analysis is performed on the parameters in the first PID algorithm, the second PID algorithm, the first PI algorithm, and the second PI algorithm. The sensitivity coefficient of each parameter to the control effect is calculated, and the parameters are categorized into high-sensitivity parameters, medium-sensitivity parameters, and low-sensitivity parameters based on the sensitivity coefficients. This includes:

[0120] For each parameter in the first PID algorithm, the second PID algorithm, the first PI algorithm, and the second PI algorithm, apply a numerical change relative to its current value while keeping other parameters constant; calculate the change in system output before and after the parameter change; obtain the sensitivity coefficient based on the ratio of the change in system output to the change in parameters;

[0121] Based on the relative magnitude of the sensitivity coefficient, parameters are classified into high-sensitivity parameters, medium-sensitivity parameters, and low-sensitivity parameters.

[0122] Specifically, the small-step iterative optimization method can be understood as approximating the optimal parameters near the steady state through multiple small adjustments. Its convergence threshold determines when to stop optimization; in this scheme, it is correlated with the decay ratio threshold to ensure that the optimization process itself does not induce oscillations. The adaptive step-size adjustment method adjusts the step size based on system feedback, such as the error rate of change and stability indicators, improving efficiency while ensuring convergence. The constrained gradient descent method refers to adjusting along the direction of fastest performance degradation during parameter updates to prevent over-adjustment.

[0123] When the system is in a state of large deviation or sluggish response and a fast adjustment strategy is activated, the high-sensitivity parameter quickly corrects the deviation with a large step size proportional to the error, shortening the adjustment time. When the system enters the vicinity of steady state and triggers a fine adjustment strategy, the high-sensitivity parameter switches to small-step iterative optimization, and its convergence accuracy is constrained by the decay ratio threshold to ensure that the optimization process does not destroy stability. During the stable operation phase, the high-sensitivity parameter is fine-tuned through gradient descent under physical constraints, and the medium-sensitivity parameter is corrected in advance based on the moving average trend of the response speed, effectively suppressing slow drift.

[0124] In some embodiments, the variation range of each parameter is obtained based on response speed, stability index, selected adjustment strategy, and parameter sensitivity level, including:

[0125] The basic adjustment range is set based on the parameter sensitivity level; among them, the basic adjustment range of high-sensitivity parameters is set to a value that can quickly improve system performance;

[0126] The basic adjustment range is adjusted according to the system response speed index; when the system response speed is lower than the preset response speed threshold, the basic adjustment range of the high sensitivity parameter is multiplied by the first adjustment coefficient, which is greater than 1; when the system response speed is higher than the preset response speed threshold, the basic adjustment range of all parameters is multiplied by the second adjustment coefficient, which is less than 1.

[0127] The basic adjustment range is adjusted according to the system stability index; when the system stability index is lower than the preset stability threshold, the basic adjustment range of all parameters is multiplied by a third adjustment coefficient, which is less than 1; when the system stability index is higher than the preset stability threshold, the basic adjustment range of the high-sensitivity parameters is multiplied by a fourth adjustment coefficient, which is greater than 1.

[0128] The basic adjustment range is adjusted according to the selected parameter adjustment strategy; when the fast adjustment strategy is selected, the basic adjustment range of all parameters is multiplied by the fifth adjustment coefficient, which is greater than 1; when the fine adjustment strategy is selected, the basic adjustment range of all parameters is multiplied by the sixth adjustment coefficient, which is less than 1; when the smooth adjustment strategy is selected, the basic adjustment range of all parameters remains unchanged.

[0129] The final change range is obtained based on the basic adjustment range, response speed adjustment coefficient, stability adjustment coefficient, and strategy adjustment coefficient.

[0130] Specifically, through the above scheme, when the system response is slow, the adjustment range of the high-sensitivity parameter is amplified to accelerate convergence; when the system has responded quickly or tended to stabilize, the adjustment intensity is suppressed to prevent over-adjustment or oscillation.

[0131] In some embodiments, the control system is further configured to:

[0132] Real-time identification of the furnace's current operating conditions; these operating conditions include the heating phase, the constant temperature phase, and the cooling phase.

[0133] A first weighting coefficient and a second weighting coefficient are generated based on the current operating conditions of the furnace body; the first weighting coefficient and the second weighting coefficient are used to correct the calculation of the third deviation and the fourth deviation, respectively;

[0134] The corrected third bias is obtained by multiplying the first weighting coefficient by the third bias.

[0135] The corrected fourth bias is obtained by multiplying the second weighting coefficient by the fourth bias.

[0136] The corrected third and fourth deviations are used to generate the final combustion control signals for the second and third burners, respectively. When the heating stage or load change stage is identified, the first and second weighting coefficients are set to values ​​less than 1 to reduce the interference of transient temperature fluctuations in the boundary area on the combustion control of adjacent zones. When the constant temperature stage is identified and the temperature fluctuation amplitudes of the first and second heating zones are both less than the preset fluctuation threshold, the first and second weighting coefficients are set to values ​​close to 1 to achieve uniformity of zone boundary temperature.

[0137] Specifically, during periods of intense dynamic change such as temperature rise or sudden load changes, the weight of the temperature signal in the boundary area is reduced to avoid erroneous adjustment of adjacent burners caused by transient thermal interference. In the steady-state stage with constant temperature and minimal temperature fluctuations, the weight is increased to close to 1 to effectively eliminate temperature differences at the boundary of the zones and improve the uniformity of the temperature field inside the furnace.

[0138] It should be noted that the dual-zone multi-couple temperature control system for a large gas furnace provided in this embodiment of the invention is used to execute all the process steps of the dual-zone multi-couple temperature control system for a large gas furnace in the above embodiment. The working principles and beneficial effects of the two are one-to-one, so they will not be described again.

[0139] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0140] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0141] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0142] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A dual-zone multi-couple temperature control system for a large gas-fired furnace, characterized in that, include: The furnace body has a first heating zone and a second heating zone inside, and a first adjacent area and a second adjacent area are provided between the first heating zone and the second heating zone. A second burner is disposed within the first adjacent area; the second burner is connected to a second combustion controller; A third burner is disposed in the second adjacent area; the third burner is connected to a third combustion controller; The first temperature sensor is used to detect the temperature of the first heating zone; The second temperature sensor is used to detect the temperature of the second heating zone; A calibration temperature sensor is set at the boundary between the first adjacent region and the second adjacent region to detect the temperature at the boundary. The control system is electrically connected to the first temperature sensor, the second temperature sensor, the calibration temperature sensor, the second combustion controller, and the third combustion controller, respectively. The control system is configured as follows: A first deviation is calculated based on the temperature detected by the first temperature sensor and the set temperature; a basic combustion control signal for the second burner is calculated based on the first deviation; a third deviation is calculated based on the temperature detected by the calibration temperature sensor and the temperature detected by the first temperature sensor; a combustion limitation ratio for the second burner is calculated based on the third deviation; the combustion limitation ratio for the second burner is combined with the basic combustion control signal to generate a final combustion control signal for the second burner, and the combustion of the second burner is controlled by the second combustion controller. A second deviation is calculated based on the temperature detected by the second temperature sensor and the set temperature; a basic combustion control signal for the third burner is calculated based on the second deviation; a fourth deviation is calculated based on the temperature detected by the calibration temperature sensor and the temperature detected by the second temperature sensor; a combustion limitation ratio for the third burner is calculated based on the fourth deviation; the combustion limitation ratio for the third burner is combined with the basic combustion control signal to generate a final combustion control signal for the third burner, and the combustion of the third burner is controlled by the third combustion controller.

2. The system according to claim 1, characterized in that, The system also includes: A first burner is disposed in the first heating zone; the first burner is connected to a first combustion controller; A fourth burner is located in the second heating zone; the fourth burner is connected to a fourth combustion controller; The control system is also electrically connected to the first combustion controller and the fourth combustion controller; The control system is also configured to: The combustion control signal of the first burner is calculated based on the first deviation, and the combustion of the first burner is controlled by the first combustion controller; The combustion control signal of the fourth burner is calculated based on the second deviation, and the combustion of the fourth burner is controlled by the fourth combustion controller.

3. The system according to claim 2, characterized in that, The control system uses the following control formula to calculate the final combustion control signals for the second and third burners: For the second burner: ; For the third burner: ; , These are the final combustion control signals for the second and third burners, respectively. The first deviation, This is the second deviation. This is the third deviation. This is the fourth deviation; , , These are the proportional gain, integral gain, and derivative gain of the first PID algorithm, respectively. , These are the proportional gain and integral gain of the first PI algorithm, respectively. , , These are the proportional gain, integral gain, and derivative gain of the second PID algorithm, respectively. , These are the proportional gain and integral gain of the second PI algorithm, respectively. , These are the first correction factor and the second correction factor, respectively. For the first burner: ; For the fourth burner: ; This is the combustion control signal for the first burner; This is the combustion control signal for the fourth burner.

4. The system according to claim 3, characterized in that, The control system is also configured to: Real-time monitoring of temperature control error, response speed, and stability indicators; Select the corresponding parameter adjustment strategy based on temperature control error, response speed and stability indicators; The parameter adjustment strategies include: rapid adjustment strategy, fine adjustment strategy, and smooth adjustment strategy; Sensitivity analysis is performed on the parameters in the first PID algorithm, the second PID algorithm, the first PI algorithm, and the second PI algorithm. The sensitivity coefficient of each parameter to the control effect is calculated, and the parameters are divided into high-sensitivity parameters, medium-sensitivity parameters, and low-sensitivity parameters according to the sensitivity coefficient. Based on the selected parameter adjustment strategy and the results of sensitivity analysis, determine the corresponding parameter adjustment method; The magnitude of change of each parameter is obtained based on the response speed, stability index, selected adjustment strategy, and parameter sensitivity level; The parameters are adjusted based on the determined parameter adjustment method and the magnitude of the parameter change.

5. The system according to claim 4, characterized in that, Based on temperature control error, response speed, and stability indicators, select the corresponding parameter adjustment strategy, including: Set a first temperature error threshold T1 and a second temperature error threshold T2, where T2 is less than T1; Obtain the absolute value of the current temperature control error; Obtain response speed metrics, including rise time and settling time; Obtain stability metrics, including overshoot and attenuation ratio; The fast adjustment strategy is selected when any of the following conditions are met: the absolute value of the current temperature control error is greater than T1, the adjustment time is greater than the preset adjustment time threshold, the overshoot is greater than the preset overshoot threshold, and the absolute value of the current temperature control error is greater than T2. The fine adjustment strategy is selected when all of the following conditions are met simultaneously: the absolute value of the current temperature control error is less than T2, the rise time is less than the preset rise time threshold, the overshoot is less than the preset overshoot threshold, and the attenuation ratio is greater than the preset attenuation ratio threshold. In other cases, choose a smooth adjustment strategy.

6. The system according to claim 5, characterized in that, Sensitivity analysis is performed on the parameters in the first PID algorithm, the second PID algorithm, the first PI algorithm, and the second PI algorithm. The sensitivity coefficient of each parameter to the control effect is calculated, and the parameters are categorized into high-sensitivity parameters, medium-sensitivity parameters, and low-sensitivity parameters based on the sensitivity coefficients, including: For each parameter in the first PID algorithm, the second PID algorithm, the first PI algorithm, and the second PI algorithm, apply a numerical change relative to its current value while keeping other parameters constant; calculate the change in system output before and after the parameter change; obtain the sensitivity coefficient based on the ratio of the change in system output to the change in parameters; Based on the relative magnitude of the sensitivity coefficient, parameters are classified into high-sensitivity parameters, medium-sensitivity parameters, and low-sensitivity parameters.

7. The system according to claim 6, characterized in that, Based on the selected parameter adjustment strategy and sensitivity analysis results, determine the corresponding parameter adjustment methods, including: When a fast adjustment strategy is selected, a large step size dynamic adjustment method is used for high-sensitivity parameters, a medium step size dynamic adjustment method is used for medium-sensitivity parameters, and low-sensitivity parameters are kept fixed. When selecting a fine-tuning strategy, a small-step iterative optimization method is used for high-sensitivity parameters, an adaptive step-size adjustment method is used for medium-sensitivity parameters, and low-sensitivity parameters are adjusted according to stability indicators. When choosing a smooth adjustment strategy, a gradient descent method under constraints is used for high-sensitivity parameters, a trend correction method based on historical data is used for medium-sensitivity parameters, and the baseline value is kept unchanged for low-sensitivity parameters. Among them, the step size of the dynamic adjustment method is proportional to the absolute value of the current temperature control error, the convergence threshold of the iterative optimization method is related to the preset attenuation ratio threshold, and the correction coefficient of the trend correction method is determined by the moving average of the response speed index.

8. The system according to claim 7, characterized in that, The magnitude of change for each parameter is obtained based on response speed, stability indicators, the selected adjustment strategy, and parameter sensitivity level, including: The basic adjustment range is set based on the parameter sensitivity level; among them, the basic adjustment range of high-sensitivity parameters is set to a value that can quickly improve system performance; The basic adjustment range is adjusted according to the system response speed index; when the system response speed is lower than the preset response speed threshold, the basic adjustment range of the high sensitivity parameter is multiplied by the first adjustment coefficient, which is greater than 1; when the system response speed is higher than the preset response speed threshold, the basic adjustment range of all parameters is multiplied by the second adjustment coefficient, which is less than 1. The basic adjustment range is adjusted according to the system stability index; when the system stability index is lower than the preset stability threshold, the basic adjustment range of all parameters is multiplied by a third adjustment coefficient, which is less than 1; when the system stability index is higher than the preset stability threshold, the basic adjustment range of the high-sensitivity parameters is multiplied by a fourth adjustment coefficient, which is greater than 1. The basic adjustment range is adjusted according to the selected parameter adjustment strategy; when the fast adjustment strategy is selected, the basic adjustment range of all parameters is multiplied by the fifth adjustment coefficient, which is greater than 1; when the fine adjustment strategy is selected, the basic adjustment range of all parameters is multiplied by the sixth adjustment coefficient, which is less than 1; when the smooth adjustment strategy is selected, the basic adjustment range of all parameters remains unchanged. The final change range is obtained based on the basic adjustment range, response speed adjustment coefficient, stability adjustment coefficient, and strategy adjustment coefficient.

9. The system according to claim 8, characterized in that, The control system is also configured to: Real-time identification of the furnace's current operating conditions; these operating conditions include the heating phase, the constant temperature phase, and the cooling phase. A first weighting coefficient and a second weighting coefficient are generated based on the current operating conditions of the furnace body; the first weighting coefficient and the second weighting coefficient are used to correct the calculation of the third deviation and the fourth deviation, respectively; The corrected third bias is obtained by multiplying the first weighting coefficient by the third bias. The corrected fourth bias is obtained by multiplying the second weighting coefficient by the fourth bias. The corrected third and fourth deviations are used to generate the final combustion control signals for the second and third burners, respectively. When the heating stage or load change stage is identified, the first and second weighting coefficients are set to values ​​less than 1 to reduce the interference of transient temperature fluctuations in the boundary area on the combustion control of adjacent zones. When the constant temperature stage is identified and the temperature fluctuation amplitudes of the first and second heating zones are both less than the preset fluctuation threshold, the first and second weighting coefficients are set to values ​​close to 1 to achieve uniformity of zone boundary temperature.

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