A method and system for ignition and operation safety interlock control of a gas rotary kiln

Abstract

This application relates to the field of kiln control technology, specifically to a method and system for ignition and operational safety interlock control of a gas rotary kiln. The method includes: during the purging stage, collecting oxygen content data from the kiln tail flue gas and kiln rotation speed data; fitting the oxygen content data to a first-order inertial plus pure time-delay model and calculating the inertial time constant and goodness of fit; releasing the ignition interlock when both satisfy the constraint conditions; during the ignition stage, calculating the fluid damping coefficient based on the inertial time constant and correcting the adjustment step size of the gas regulating valve opening; during the operation stage, performing order frequency shift correction on the combustion characteristic frequency band based on the kiln rotation speed and determining whether it is a true flameout or a sensor failure. This application ensures the effectiveness of purging through flow field physical fingerprint verification, achieves adaptive ignition control using the fluid damping coefficient, and uses frequency domain fingerprint features to achieve anti-interference flameout determination, thus improving the ignition and operational safety of the gas rotary kiln.

Description

Technical Field

[0001] This application relates to the field of kiln control technology. More specifically, this application relates to a method and system for ignition and operation safety interlock control of a gas rotary kiln. Background Technology

[0002] Rotary kilns are widely used in industries such as metallurgy, building materials, and chemicals. Their combustion devices typically use industrial coal gas, such as blast furnace gas and coke oven gas, as fuel. Coal gas fuels generally have characteristics such as low calorific value, slow combustion speed, large fluctuations in pipeline pressure, and the presence of toxic carbon monoxide, making both the ignition and operation phases of rotary kilns highly risky. Insufficient pre-ignition purging, improper handling of ignition failures, and flameout or backfire caused by pressure fluctuations or abnormal combustion conditions during operation can all lead to deflagration or gas leaks.

[0003] Existing rotary kiln control schemes primarily focus on temperature control, combustion optimization, and energy-saving control. For example, one rotary kiln control scheme employs a three-level control structure, including a primary rotary kiln detection subsystem, a secondary control subsystem, and a tertiary diagnostic decision-making subsystem. It utilizes pattern recognition technology to establish a knowledge base and control rule set, and employs a multi-dimensional extreme value search method to find the control point with optimal combustion effect and lowest energy consumption. Another scheme automatically adjusts fuel supply and airflow by detecting the kiln body radiation temperature, kiln head flame temperature, and kiln tail flue temperature and comparing them with preset benchmark values. However, these schemes lack sufficient coverage of dedicated safety procedures such as pre-ignition purging, ignition window, and ignition failure protection.

[0004] The operation control process of a rotary kiln includes steps such as ignition environment confirmation, purging stage, ignition stage, and flame detection and safety protection during operation. Existing technologies have at least the following shortcomings: a lack of a dedicated integrated ignition and operation safety control scheme for gas rotary kilns; separation of control between the purging, ignition, and operation stages, resulting in logical gaps during stage switching; incomplete safety interlocking conditions, failing to cover the risks associated with multiple coupled parameters such as gas pressure fluctuations, abnormal oxygen content, abnormal kiln speed, and changes in operating conditions; and a lack of interference-resistant flameout monitoring mechanisms during operation, making it highly susceptible to false shutdowns due to sensor malfunctions or untimely responses under high-risk conditions. Summary of the Invention

[0005] The purpose of this application is to propose a method and system for ignition and operation safety interlock control of a gas rotary kiln, in order to solve the problems of disconnected ignition and operation control, incomplete safety interlock conditions, and sensor failure leading to misjudgment in the prior art.

[0006] In the first aspect, this application provides a method for ignition and operation safety interlock control of a gas rotary kiln. The control method includes: during the purging stage, real-time acquisition of oxygen content data and kiln rotation speed data of the kiln tail flue gas; fitting the oxygen content data to a first-order inertial plus pure time delay model; calculating the inertial time constant and goodness of fit in the model; releasing the ignition interlock when the goodness of fit is greater than a preset fitting confidence level and the inertial time constant is within the effective range; during the ignition stage, calculating the fluid damping coefficient based on the current inertial time constant and a preset standard operating condition time constant; and calculating the first derivative of the furnace temperature in real time as the temperature rise. When the temperature rise rate is lower than the preset temperature rise target value, the preset basic adjustment step size is weighted and corrected using the fluid damping coefficient, and the opening of the gas regulating valve is adjusted according to the corrected step size. During operation, when the flame detector signal is lower than the warning threshold, the order frequency offset is calculated based on the kiln rotation speed, and the preset static combustion characteristic frequency band is superimposed to generate a dynamic monitoring window. The furnace pressure signal is subjected to spectral transformation, and the power spectral density integral within the dynamic monitoring window is calculated. When the power spectral density integral is greater than the preset power spectral threshold, it is determined to be a sensor fault and an alarm is triggered; otherwise, it is determined to be a real flameout and the gas shut-off valve command is executed.

[0007] This application establishes physical fingerprint parameters of the flow field during the purging stage and applies these parameters in conjunction with the ignition and operation stages, achieving integrated safety interlock control of the gas rotary kiln's ignition and operation. By introducing an order frequency shift correction mechanism based on the kiln's rotational speed, the flameout determination during the operation stage can effectively distinguish between actual flameout and sensor malfunctions, significantly reducing the false shutdown rate.

[0008] Optionally, fitting the oxygen content data to a first-order inertial plus pure time-delay model includes: pre-setting a response function describing the change of oxygen content over time, the response function consisting of an ambient oxygen content baseline value and an exponential decay term; the exponential decay term characterizing the process of oxygen content transitioning from the initial value to the ambient oxygen content baseline value; introducing an inertial time constant as a control parameter for the decay rate and introducing pure time delay as a control parameter for the response delay in the exponential decay term, thereby establishing the first-order inertial plus pure time-delay model.

[0009] This application employs a first-order inertial plus pure time delay model to model the oxygen content change process during the purging stage. This model can accurately describe the dynamic response characteristics of the flue gas flow field. By introducing two parameters, the inertial time constant and the pure time delay, it can characterize both the gas exchange response speed of the flue and reflect the transmission delay between the sampling point and the flue outlet, thus providing a reliable physical basis for subsequent flow field effectiveness determination.

[0010] Optionally, the calculation process of the inertial time constant and the goodness of fit includes: using a nonlinear iterative optimization algorithm to optimize the inertial time constant and the pure lag time with the objective of minimizing the sum of squared residuals between the collected oxygen content data and the calculated value of the response function; after the iteration converges, the optimal inertial time constant is output, and the statistics characterizing the goodness of fit of the model are calculated simultaneously as the goodness of fit.

[0011] Optionally, the step of determining the effective range includes: pre-establishing an inverse mapping relationship between the inertial time constant limit and the kiln rotation speed; and finding the allowable upper limit and allowable lower limit corresponding to the current kiln rotation speed according to the inverse mapping relationship, so as to constitute the effective range.

[0012] This application establishes an inverse mapping relationship between the inertial time constant limit and the kiln rotation speed, enabling the effective range to dynamically adjust with changes in the kiln rotation speed. When the kiln rotation speed is high, the flue gas flow velocity increases, and the gas exchange time constant decreases accordingly, causing the effective range to shrink towards a smaller value; conversely, when the kiln rotation speed is low, the effective range expands towards a larger value. This dynamic mapping mechanism can adapt to the differences in flow field characteristics under different operating conditions of the rotary kiln, avoiding misjudgments caused by using a fixed threshold.

[0013] Optionally, the calculation steps of the fluid damping coefficient include: obtaining a preset standard operating condition time constant, wherein the standard operating condition time constant characterizes the ideal ventilation response speed under standard flow field conditions; calculating the ratio of the standard operating condition time constant to the current inertial time constant; and determining the ratio as the fluid damping coefficient, such that the value of the fluid damping coefficient is negatively correlated with the current inertial time constant.

[0014] Optionally, the opening adjustment process of the gas regulating valve includes: calculating the difference between the preset temperature rise target value and the current temperature rise rate, amplifying the difference using a preset ratio to obtain a basic adjustment step size; multiplying the fluid damping coefficient by the basic adjustment step size to obtain an execution step size, and adjusting the opening of the gas regulating valve accordingly.

[0015] This application multiplies the fluid damping coefficient by the basic adjustment step size to obtain the final target execution step size, thus achieving adaptive adjustment of the gas supply. When the inertial time constant is large, i.e., the flue gas flow field hysteresis is high, the fluid damping coefficient is less than one, which can effectively reduce the valve opening rate and prevent deflagration caused by gas accumulation in the furnace; when the inertial time constant is small, i.e., the flow field is unobstructed, the fluid damping coefficient is close to or greater than one, allowing for faster valve response to meet the heating requirements.

[0016] Optionally, the calculation of the order frequency offset includes: establishing a linear coupling relationship between the kiln rotation speed and the mechanical vibration frequency based on the principle of rotating machinery vibration; multiplying the currently collected kiln rotation speed by a preset mechanical order ratio coefficient to obtain the corresponding frequency change value; and determining the frequency change value as the order frequency offset, which is used to characterize the amount of shift in the background noise frequency band caused by mechanical rotation.

[0017] Optionally, the calculation process of the power spectral density integral includes: converting the furnace pressure signal in the time domain into spectral data in the frequency domain using a fast Fourier transform algorithm; determining the upper and lower limits of the frequency of the dynamic monitoring window formed by superimposing the order frequency offset on a preset static combustion characteristic frequency band; and performing an integral calculation on the amplitude of the spectral data within the upper and lower limits of the frequency of the dynamic monitoring window to obtain the power spectral density integral characterizing the total energy within the dynamic monitoring window.

[0018] Optionally, the criteria for determining sensor failure and actual flameout include: comparing the calculated power spectral density integral with the preset power spectral threshold; if the integral value is greater than the preset power spectral threshold, it indicates that there are still combustion-specific acoustic features in the furnace, maintaining operation and issuing a maintenance alarm; if the integral value is less than or equal to the preset power spectral threshold, it indicates that the combustion acoustic features in the furnace have disappeared, determining that the flame is completely extinguished, and executing the gas shut-off valve command.

[0019] This application distinguishes between actual flameout and sensor malfunction by comparing the power spectral density integral with a preset threshold. When the flame detector signal is abnormal but the power spectral density integral is still higher than the threshold, it indicates that the acoustic characteristics of combustion in the furnace still exist, and it is determined to be a sensor malfunction rather than actual flameout, thus avoiding unnecessary downtime losses. When the power spectral density integral is lower than the threshold, it indicates that the combustion acoustic characteristics have disappeared, and it is determined to be actual flameout, and a safety shutdown is immediately executed, ensuring rapid response in emergency situations.

[0020] In the second aspect, an ignition and operation safety interlock control system for a gas rotary kiln includes:

[0021] processor;

[0022] The memory stores computer instructions for an ignition and operation safety interlock control system for a gas rotary kiln, which, when executed by the processor, cause the system to perform the aforementioned ignition and operation safety interlock control method for a gas rotary kiln.

[0023] The beneficial effects of this application are as follows: This application establishes physical fingerprint parameters of the flow field during the purging stage and applies these parameters in conjunction with the ignition and operation stages, realizing integrated safety interlocking control of the gas rotary kiln's ignition and operation. By using the inertial time constant as the calculation basis for the fluid damping coefficient, the gas supply during the ignition stage can be adaptively adjusted according to the actual state of the current flue gas flow field, avoiding the risk of deflagration caused by rapid gas injection when the flow field is obstructed. By introducing an order frequency shift correction mechanism based on the kiln's rotational speed, the flameout determination during the operation stage can effectively distinguish between actual flameout and sensor malfunction, significantly reducing the false shutdown rate and improving the safety of the gas rotary kiln's operation. Attached Figure Description

[0024] Figure 1 This is a flowchart of an ignition and operation safety interlock control method for a gas rotary kiln according to an embodiment of this application.

[0025] Figure 2 This is a diagram illustrating the adaptive gas regulation control process during the ignition stage of a gas rotary kiln ignition and operation safety interlock control method according to an embodiment of this application.

[0026] Figure 3 This is a structural block diagram of an ignition and operation safety interlock control system for a gas rotary kiln according to an embodiment of this application. Detailed Implementation

[0027] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Figure 1 The diagram shown is a flowchart of an ignition and operation safety interlock control method for a gas rotary kiln according to an embodiment of this application.

[0028] S1: Perform flow field physical fingerprint modeling and verification during the purging phase.

[0029] During the purging phase, physical fingerprint modeling and verification of the flow field are performed to ensure the physical connectivity of the flue gas duct and the effectiveness of the purging. After the controller issues a purging command, oxygen content data of the kiln tail flue gas and speed data of the kiln main motor are collected synchronously at fixed intervals. In this embodiment, the sampling period is set to 100 milliseconds. Oxygen content data is obtained by a zirconia oxygen sensor installed in the kiln tail flue, and speed data is obtained by an encoder installed in the kiln main motor.

[0030] A predetermined response function is used to describe the change of oxygen content over time. This response function is represented by a first-order inertial plus pure time-delay model. The mathematical form of the response function is as follows:

[0031] ;

[0032] in, Indicates time The oxygen content value, in percentage; This represents the baseline value for ambient oxygen content; This indicates the initial oxygen content at the start of the purging process; Indicates the pure time delay, in seconds; The inertial time constant is expressed in seconds. The exponential decay term characterizes the process of oxygen content transitioning from its initial value to the ambient oxygen content baseline.

[0033] The controller employs a nonlinear iterative optimization algorithm to fit the collected oxygen content time-series data. In this embodiment, the Levenberg-Marquardt iterative algorithm is used to optimize the inertial time constant and pure time delay by minimizing the sum of squared residuals between the collected oxygen content data and the calculated value of the response function. After the iteration converges, the optimal inertial time constant is output, and the goodness of fit is calculated simultaneously. As a statistic characterizing the goodness of fit of a model.

[0034] The controller then performs dual logic checks. First, it confirms the goodness of fit. The calculated inertial time constant is greater than the preset fitting confidence level. In this embodiment, the preset fitting confidence level is set to 0.95 to exclude data anomalies caused by oxygen sensor malfunction. Next, it is confirmed whether the calculated inertial time constant falls within the effective range corrected based on the current kiln rotation speed. The steps for determining the effective range include: pre-establishing an inverse mapping relationship between the inertial time constant limit and the kiln rotation speed; and, based on the inverse mapping relationship, finding the allowable upper limit and allowable lower limit values ​​corresponding to the current kiln rotation speed to constitute the effective range. In this embodiment, the upper limit value of the effective range is calculated by dividing the current kiln rotation speed by a pre-calibrated first empirical coefficient, and the lower limit value of the effective range is calculated by dividing the current kiln rotation speed by a pre-calibrated second empirical coefficient.

[0035] If the inertial time constant exceeds the upper limit of the effective range, it indicates that the air exchange response is too slow, which may be due to duct blockage or insufficient air volume. If the inertial time constant is below the lower limit of the effective range, it indicates that the air exchange response is too fast, which may be due to bypass leakage. Only when both of the above dual checks pass will the controller release the ignition lockout, store the currently calculated inertial time constant in the global variable register, and store the kiln rotation speed in the speed register, as key input parameters for subsequent ignition and operation phases.

[0036] S2: Performs impedance-coupled adaptive gas regulation control during the ignition phase.

[0037] During the ignition phase, impedance-coupled adaptive gas regulation control is implemented to achieve safe and efficient regulation of the gas supply. Once the ignition gun successfully ignites the gas and the main gas valve is opened to its minimum degree, the controller reads the inertial time constant parameter stored in the register.

[0038] The fluid damping coefficient is calculated based on the current inertial time constant and a preset standard operating time constant. The calculation steps include: obtaining the preset standard operating time constant, which represents the ideal ventilation response speed under standard unobstructed flow conditions (set to 15 seconds in this embodiment); calculating the ratio of the standard operating time constant to the current inertial time constant; and determining this ratio as the fluid damping coefficient. Therefore, the value of the fluid damping coefficient is negatively correlated with the current inertial time constant; a larger inertial time constant results in a smaller fluid damping coefficient, and vice versa.

[0039] The controller enters a fixed-cycle cyclic control mode; in this embodiment, the control cycle is set to 50 milliseconds. Since thermocouple signals in industrial environments are often accompanied by high-frequency electromagnetic interference and thermal fluctuations, direct differentiation would amplify the noise, leading to control divergence. Therefore, within each control cycle, the controller first uses a moving average filtering algorithm to smooth the N most recently collected furnace temperature sampling points, obtaining smoothed temperature data with a high signal-to-noise ratio. Subsequently, the controller calculates the first derivative of the smoothed temperature data as the temperature rise rate using a differential algorithm. The furnace temperature is obtained by thermocouples installed on the inner wall of the furnace.

[0040] When the temperature rise rate is lower than the preset temperature rise target value, the controller needs to increase the opening of the gas regulating valve to increase the gas supply. The gas regulating valve opening adjustment process includes: calculating the difference between the preset temperature rise target value and the current temperature rise rate; amplifying the difference using a preset proportional gain to obtain an uncorrected basic adjustment step size; multiplying the fluid damping coefficient by the basic adjustment step size to obtain the target execution step size and adjusting the opening of the gas regulating valve accordingly.

[0041] The core of this step lies in the fact that a large inertial time constant measured during the purging phase indicates poor flue gas exhaust or high flow resistance in the furnace. In this case, the fluid damping coefficient will be less than one, thus forcibly reducing the valve opening rate. This mechanism can compensate for fluctuations in the calorific value of the gas while preventing deflagration accidents caused by rapid gas injection under adverse flow field conditions. When the inertial time constant is small, i.e., the flow field is unobstructed, the fluid damping coefficient is close to or greater than one, allowing for a faster valve response to meet the heating requirements.

[0042] The controller continues to execute the above-mentioned cyclic control until the furnace temperature reaches the preset stable operating temperature threshold. At this point, the ignition phase ends and the normal operation phase begins.

[0043] Figure 2 This diagram illustrates the adaptive gas regulation control process during the ignition stage of a gas rotary kiln ignition and operation safety interlock control method according to an embodiment of this application. The diagram reflects the response process of adaptive control of the gas regulating valve using the fluid damping coefficient during the ignition stage. The gas regulating valve opening curve in the diagram exhibits a stepped upward trend, indicating that the uncorrected basic regulation step size has been weighted and corrected based on the fluid damping coefficient, thereby limiting the valve opening rate. This control mechanism ensures that when the temperature rise rate is lower than the preset temperature rise target value, the gas supply can be dynamically adjusted according to the flow field hysteresis, preventing deflagration caused by excessively rapid gas injection.

[0044] S3: During operation, perform anti-interference shutdown monitoring based on speed frequency shift correction.

[0045] During operation, anti-interference flameout monitoring based on speed frequency shift correction is implemented to accurately distinguish between actual flameout and sensor malfunction. During normal operation, the controller continuously monitors the signal strength of the optical flame detector.

[0046] When the flame detector signal falls below the warning threshold, the controller does not immediately trigger an emergency shutdown, but instead initiates a frequency domain fingerprint verification subroutine. In this embodiment, the warning threshold is set to 20% of the normal signal strength, and the duration threshold is set to 2 seconds. That is, frequency domain fingerprint verification is triggered when the flame detector signal remains below 20% for more than 2 seconds.

[0047] First, the order frequency offset is calculated based on the kiln rotation speed. The steps for calculating the order frequency offset include: establishing a linear coupling relationship between the kiln rotation speed and the mechanical vibration frequency based on the principle of rotating machinery vibration; multiplying the currently acquired kiln rotation speed by a preset mechanical order ratio coefficient to obtain the corresponding frequency change value; and determining the frequency change value as the order frequency offset. In this embodiment, the controller reads the real-time acquired kiln rotation speed, multiplies the rotation speed value by a pre-calibrated mechanical order ratio coefficient, and determines the resulting product as the order frequency offset; wherein, in this embodiment, the mechanical order ratio coefficient is set to 0.5 Hz per revolution per minute.

[0048] The preset static combustion characteristic frequency band is superimposed with the order frequency offset to generate a dynamic monitoring window. In this embodiment, the static combustion characteristic frequency band is set to 25 Hz to 45 Hz. The controller acquires the furnace pressure signal and performs signal preprocessing and spectrum transformation. Since the original furnace pressure signal contains DC components and high-frequency noise, direct spectrum transformation can easily mask the characteristics. Therefore, the controller first performs detrending processing on the acquired time-domain pressure signal to eliminate DC bias, and uses a low-pass filter to filter out noise interference higher than the upper limit frequency of the dynamic monitoring window.

[0049] The controller acquires the furnace pressure signal and performs a spectrum transformation. The calculation process of the power spectral density integral includes: converting the furnace pressure signal in the time domain into frequency domain spectrum data using a fast Fourier transform algorithm; determining the upper and lower limits of the frequency of the dynamic monitoring window formed by superimposing the order frequency offset on a preset static combustion characteristic frequency band; and integrating the amplitude of the spectrum data within the upper and lower limits of the frequency of the dynamic monitoring window to obtain the power spectral density integral characterizing the total energy within the dynamic monitoring window.

[0050] Finally, flameout determination is performed based on the power spectral density integral. The determination conditions for sensor failure and actual flameout include: comparing the calculated power spectral density integral with the preset power spectral threshold; if the integral value is greater than the preset power spectral threshold, it indicates that the characteristic acoustic features of combustion still exist in the furnace, and it is determined to be a flame detector sensor failure rather than actual flameout. The controller continues to operate and issues a maintenance alarm to notify maintenance personnel to check the flame detector; if the integral value is less than or equal to the preset power spectral threshold, it indicates that the acoustic features of combustion in the furnace have disappeared, and it is determined to be that the flame is completely extinguished. The controller immediately executes the command to cut off the gas quick-cut valve, and at the same time shuts down the combustion fan and starts the emergency purging procedure.

[0051] According to a second aspect of this application, this application also provides an ignition and operation safety interlock control system for a gas rotary kiln. Figure 3 This is a structural block diagram of an ignition and operation safety interlock control system for a gas rotary kiln according to an embodiment of this application. Figure 3 As shown, the system includes a processor and a memory. The memory stores computer program instructions, which, when executed by the processor, implement the ignition and operation safety interlock control method for a gas rotary kiln according to the first aspect of this application. The system also includes other components well-known to those skilled in the art, such as a communication bus and a communication interface. Their configuration and functions are known in the art and will not be described further here.

[0052] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and inventive concept of this application, should be within the scope of protection of this application.

Claims

1. A method for ignition and operation safety interlock control of a gas rotary kiln, characterized in that, The control method includes: During the purging stage, real-time data on oxygen content and kiln rotation speed of the kiln tail gas are collected. The oxygen content data is fitted to a first-order inertial plus pure lag model, and the inertial time constant and pure lag time in the model are calculated. Then, the goodness of fit is calculated. When the goodness of fit is greater than the preset fit confidence level and the inertial time constant is within the effective range, the ignition lockout is released. During the ignition phase, the fluid damping coefficient is calculated based on the current inertial time constant and the preset standard operating time constant, including: obtaining the preset standard operating time constant, which represents the ideal gas exchange response speed under standard flow field conditions; calculating the ratio of the standard operating time constant to the current inertial time constant; determining the ratio as the fluid damping coefficient, such that the value of the fluid damping coefficient is negatively correlated with the current inertial time constant; calculating the first derivative of the furnace temperature in real time as the temperature rise rate; when the temperature rise rate is lower than the preset temperature rise target value, using the fluid damping coefficient to perform a weighted correction on the preset basic adjustment step size, and adjusting the opening of the gas regulating valve according to the corrected step size; During operation, when the flame detector signal is below the warning threshold, the order frequency offset is calculated based on the kiln rotation speed. This includes: establishing a linear coupling relationship between the kiln rotation speed and the mechanical vibration frequency based on the principle of rotating machinery vibration; multiplying the currently collected kiln rotation speed by a preset mechanical order ratio coefficient to obtain the corresponding frequency change value; determining the frequency change value as the order frequency offset, which is used to characterize the shift of the background noise frequency band caused by mechanical rotation, and superimposing a preset static combustion characteristic frequency band to generate a dynamic monitoring window; performing a spectrum transformation on the furnace pressure signal and calculating the power spectral density integral within the dynamic monitoring window; if the power spectral density integral is greater than a preset power spectral threshold, it is determined to be a sensor fault and an alarm is triggered; otherwise, it is determined to be a true flameout and a gas shut-off valve command is executed.

2. The method for ignition and operation safety interlock control of a gas rotary kiln according to claim 1, characterized in that, The oxygen content data is fitted to a first-order inertial plus pure hysteresis model, including: A response function is predefined to describe the change of oxygen content over time. The response function consists of an ambient oxygen content baseline value and an exponential decay term. The exponential decay term is used to characterize the process of oxygen content transitioning from the initial value to the ambient oxygen content baseline value. An inertial time constant is introduced as a control parameter for the decay rate in the exponential decay term, and a pure time delay is introduced as a control parameter for the response delay, thereby establishing the first-order inertial plus pure time delay model.

3. The method for ignition and operation safety interlock control of a gas rotary kiln according to claim 2, characterized in that, The calculation process for the inertial time constant and the pure time delay includes: A nonlinear iterative optimization algorithm is used to optimize the inertial time constant and pure time delay by minimizing the sum of squared residuals between the collected oxygen content data and the calculated value of the response function. After the iteration converges, the optimal inertial time constant is output, and the statistics characterizing the goodness of fit of the model are calculated simultaneously as the goodness of fit.

4. The method for ignition and operation safety interlock control of a gas rotary kiln according to claim 1, characterized in that, The steps for determining the effective interval include: Establish a pre-defined inverse mapping relationship between the inertial time constant limit and the kiln rotation speed; Based on the inverse mapping relationship, find the upper and lower allowable limits corresponding to the current kiln rotation speed to form the effective range.

5. The method for ignition and operation safety interlock control of a gas rotary kiln according to claim 1, characterized in that, The opening adjustment process of the gas regulating valve includes: Calculate the difference between the preset temperature rise target value and the current temperature rise rate, and amplify the difference using a preset ratio to obtain the basic adjustment step size; The fluid damping coefficient is multiplied by the basic adjustment step size to obtain the execution step size, and the opening of the gas regulating valve is adjusted accordingly.

6. The method for ignition and operation safety interlock control of a gas rotary kiln according to claim 1, characterized in that, The calculation process of the power spectral density integral includes: The furnace pressure signal in the time domain is converted into spectral data in the frequency domain using the Fast Fourier Transform algorithm; Determine the upper and lower limits of the frequency of the dynamic monitoring window formed by superimposing the order frequency offset on the preset static combustion characteristic frequency band; The amplitude of the spectral data within the upper and lower frequency limits of the dynamic monitoring window is integrated to obtain the power spectral density integral, which represents the total energy within the dynamic monitoring window.

7. The method for ignition and operation safety interlock control of a gas rotary kiln according to claim 1, characterized in that, The criteria for determining sensor malfunction and actual engine shutdown include: The calculated power spectral density integral is compared with the preset power spectral threshold. If the integral value is greater than the preset power spectrum threshold, it indicates that there are still combustion-specific acoustic characteristics in the furnace, and operation is maintained and a maintenance alarm is issued. If the integral value is less than or equal to the preset power spectrum threshold, it indicates that the combustion sound characteristics in the furnace have disappeared, and it is determined that the flame is completely extinguished, and the gas shut-off valve command is executed.

8. A safety interlock control system for the ignition and operation of a gas rotary kiln, characterized in that, include: processor; A memory, wherein a computer program is stored; Wherein, the processor is configured to execute the computer program to implement the ignition and operation safety interlock control method for a gas rotary kiln as described in any one of claims 1 to 7.

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