CN-122012912-A - Method and system for detecting steady-state operating point drift in continuous annealing process of cold-rolled strip steel

CN122012912ACN 122012912 ACN122012912 ACN 122012912ACN-122012912-A

Abstract

The invention relates to a heating furnace steady-state operating point drift detection and positioning method based on multi-source data fusion, and belongs to the technical field of ferrous metallurgy automatic control. Aiming at the problem of steady-state operating point drift in the operation process of a heating furnace, a group of drift sensitivity indexes including a furnace temperature standardized residual error, a furnace temperature drift rate, a temperature-energy consistency index and the like are constructed by collecting multi-source data such as the running speed of strip steel, the furnace temperature of each furnace area, the gas flow, the air flow and the outlet plate temperature, smoothing is carried out by adopting an exponential weighted moving average method, the drift intensity of each furnace area and the overall drift intensity of the plate temperature are calculated, so that whether the steady-state operating point drift occurs or not is judged, and when the drift occurs, the dominant furnace area and the drift direction are positioned. The invention can realize the on-line monitoring and diagnosis of the steady-state operating point of the heating furnace and improve the running stability of the heating furnace and the control precision of the product quality.

Inventors

JIANG XU
SONG WENSHUO
ZHANG KAI
CAO YUAN
ZHANG SHAOQIANG
LU JIAHAO
DU RUITAO

Assignees

中冶南方工程技术有限公司

Dates

Publication Date: 20260512
Application Date: 20260105

Claims (10)

1. The steady-state operating point drift online detection method for the continuous annealing heating process of the cold-rolled strip steel is characterized by comprising the following steps of: S1, calculating total causal time difference between plate temperature and heating conditions of each furnace area, and carrying out space-time alignment on strip steel furnace outlet plate temperature data and variable data of heating sections of each furnace area based on the total causal time difference to obtain an aligned data sequence; S2, processing the aligned data sequences based on the furnace temperature standard deviation and the outlet plate temperature standard deviation to construct a group of drift sensitivity indexes, wherein the drift sensitivity indexes at least comprise furnace temperature standardized residual errors, plate temperature standardized residual errors, furnace temperature drift rates of all areas, plate Wen Piaoyi rates and temperature-energy consistency indexes; S3, smoothing the drift sensitive index, calculating the drift intensity of each furnace area and the overall drift intensity of the plate temperature based on the smoothed index, judging whether the steady-state operating point drift occurs according to the drift intensity of each furnace area and the overall drift intensity of the plate temperature, and positioning the main furnace area and the drift direction when the drift occurs.
2. The method according to claim 1, wherein in step S1 the total causal time difference Calculated by the following formula: ; Wherein the method comprises the steps of For the running time of the strip steel in the furnace zone a, , For the length of the furnace zone a, Is the running speed of the strip steel, Is the thermal response time difference; The total causal time difference For pressing the temperature data of the strip steel outlet plate and the variable data of the heating section of the corresponding furnace zone And (3) aligning to obtain an aligned variable sequence under a unified time grid, wherein the aligned variable sequence comprises the aligned furnace temperature of each region, the gas flow of each region, the combustion air flow of each region and the aligned outlet plate temperature.
3. The method of claim 1, wherein the variable data of the heating section of each furnace zone comprises furnace temperature, gas flow rate of each zone and combustion air flow rate of each zone, and the following conditions are satisfied in the step S1: the change amplitude of the furnace temperature set value of each zone does not exceed a first threshold value The method comprises the following steps: ; The gas flow rate of each zone does not change more than a second threshold value The method comprises the following steps: ; The air flow rate of each zone does not change more than a third threshold value The method comprises the following steps: ; The standard deviation of the temperature of the outlet plate does not exceed a fourth threshold value The method comprises the following steps: ; Wherein, the 、、、 According to the requirements of steel works/processes, the screening conditions are set on a sliding window In, the alignment variable sequence is judged, and when all conditions are met, the window center is determined Incorporation of steady state reference regions ; Wherein, the Indicating the furnace temperature set value of the furnace zone a after alignment, Indicating the aligned a-furnace zone gas flow, Indicating the aligned furnace area a combustion air flow, To take the following measures Is the center and the window length is Is provided with a sliding window which is arranged on the upper surface of the glass substrate, And Is a window The judging formula shows that the absolute value of the difference value of any two time points of the furnace temperature set value of each zone, the gas flow rate of each zone and the air flow rate of each zone does not exceed the corresponding threshold value in the sliding window.
4. The method according to claim 1, wherein the furnace temperature of each zone is normalized to a residual in step S2 The calculation formula of (2) is ; The plate temperature standardized residual error The calculation formula of (2) is ; Wherein, the For the actual furnace temperature of the aligned furnace zone a, Is a furnace temperature set value of a furnace zone, The standard deviation of the furnace temperature of the furnace area is a; for the temperature of the aligned outlet plate, Is the set value of the plate temperature, Is the outlet plate temperature standard difference.
5. The method according to claim 1, wherein the furnace temperature drift rate of each zone in step S2 The calculation formula of (2) is as follows: ; Board Wen Piaoyi ratio The calculation formula of (2) is as follows: ; temperature-energy consistency index The calculation formula of (2) is as follows: ; Wherein, the To take the following measures Is the center and the window length is Is provided with a sliding window which is arranged on the upper surface of the glass substrate, As the mean value of the time series within the window, Is the average value of the furnace temperature sequence of the furnace zone a in the window, Is the mean value of the temperature sequence in the window, To at the same time The actual furnace temperature of the furnace zone a after alignment, To at the same time The temperature of the outlet plate after alignment, For aligned furnace zone a gas flow, Is the average value of the gas flow sequence in the furnace zone a in the window, Is the average value of the furnace temperature sequence of the furnace zone a in the window, and epsilon is an extremely small constant for preventing denominator from being zero.
6. The method according to claim 1, wherein the smoothing in step S3 employs an exponentially weighted moving average method, and specifically comprises: calculating the smoothed furnace temperature standardized residual error of each region : ; Calculating the furnace temperature drift rate of each region after smoothing : ; Calculating smoothed plate temperature standardized residual error : ; Calculate the smoothed plate Wen Piaoyi rate: ; Wherein, the The residual error is normalized for the furnace temperature of each zone, For the drift rate of the furnace temperature of each zone, For the plate temperature to be normalized to the residual, For the rate of the board Wen Piaoyi to be high, Is the EWMA smoothing coefficient of the temperature, EWMA smoothing coefficient for temperature slope, and ≤ 。
7. The method according to claim 1, wherein the drift intensity of each furnace zone in step S3 The calculation formula of (2) is as follows: ; Wherein, the The furnace temperature deviation of the furnace zone a is scored, The furnace temperature drift rate of the furnace zone a is scored, Scoring the temperature-energy consistency of the a-oven zone, Is non-negative weight and satisfies + + =1; Wherein, the furnace temperature deviation score of each zone Furnace temperature drift rate scoring for each zone Score of board Wen Piancha Score of board Wen Piaoyi rate Temperature-energy consistency scoring The calculation formulas of (a) are respectively as follows: ; ; ; ; ; Wherein, the For the normalized residual error of the furnace temperature of the furnace zone a after smoothing, For the smoothed a furnace temperature drift rate of the furnace zone, Is a furnace temperature drift rate reference value of a furnace area, To normalize the residual for the smoothed plate temperature, For the smooth board Wen Piaoyi rate, Is a reference value for the rate of the board Wen Piaoyi, Is an index of the temperature-energy consistency of the furnace zone.
8. The method according to claim 7, wherein the plate temperature in step S3 has an overall drift intensity The calculation formula of (2) is as follows: ; Wherein, the The board Wen Piancha was scored for the number of points, The rate of the board Wen Piaoyi was scored, 、 Is a non-negative weight coefficient and satisfies 。
9. The method according to claim 8, wherein determining whether a steady-state operating point drift occurs based on the drift intensity of each furnace zone and the overall drift intensity of the plate temperature, and locating the dominant furnace zone and the drift direction when determining that a drift occurs, comprises: At the position of Calculating drift intensity of all furnace areas at the moment The furnace region in which the drift intensity is the greatest is called the dominant furnace region, The time-leading furnace zone is recorded as ; ; Setting two thresholds, namely a furnace temperature drift threshold Sum board Wen Piaoyi threshold ; If it is Indicating that the fluctuation of the temperatures of all furnace areas is within an acceptable range, and judging that no obvious steady-state operating point drift is detected at the current moment; If it is Indicating that the temperature of the furnace zone has drift of a steady-state operating point at the current moment, and determining the drift rate of the furnace temperature corresponding to the furnace zone by leading the furnace zone Judging whether the drift direction of the temperature of the furnace area is heating or cooling; Similarly, the overall strength of the judgment board Wen Piaoyi: If it is The fluctuation of the plate temperature is within an acceptable range, and the judgment is that no obvious steady-state operating point drift is detected at the current moment; If it is Judging that the steady-state operating point drift occurs at the current moment and the furnace temperature drift rate corresponding to the main furnace area is passed Judging whether the drift direction is heating or cooling; Wherein the furnace temperature drift rate through the dominant furnace zone Judging whether the drift direction is rising or falling, specifically comprising: If it is Judging the drift direction as heating; If it is And judging the drift direction as cooling.
10. Steady state operating point drift on-line detection system for continuous annealing heating process of cold rolled steel strip, applying the method according to claims 1-9, characterized in that the system comprises: The system comprises a data alignment and baseline construction module, an alignment variable sequence, a steady-state reference area screening and a baseline statistic, wherein the data alignment and baseline construction module is configured to calculate total causal time difference between plate temperature and heating conditions of each furnace area based on the running speed of strip steel and the length of each furnace area; A drift sensitivity index calculation module configured to calculate a set of drift sensitivity indexes in real time based on the aligned variable sequence and the baseline statistic, the drift sensitivity indexes including a normalized residual calculated based on the baseline statistic, a drift rate calculated based on a sliding window linear fit, and a temperature-energy consistency index characterizing a gas flow and furnace temperature response relationship; And when the comprehensive drift intensity exceeds a preset threshold value, judging that a steady-state operating point drifts, and identifying the furnace area and the drift direction of the dominant drift.

Description

Method and system for detecting steady-state operating point drift in continuous annealing process of cold-rolled strip steel Technical Field The invention relates to the technical field of automatic control of ferrous metallurgy, in particular to a steady-state operating point drift online detection method for a continuous annealing heating process of cold-rolled strip steel. Background The continuous annealing heating process (hereinafter referred to as a "cold rolling continuous annealing process") of the cold-rolled strip steel refers to a process of continuously passing the coiled strip steel through a continuous annealing furnace to perform heat treatment. The strip steel is a coiled steel product with narrower width and thinner thickness, and the steel grade comprises various types (such as galvanized, oriented silicon steel GO, non-oriented silicon steel NGO and the like). According to different steel types and performance requirements, the annealing process system and equipment configuration are correspondingly adjusted. In actual production, in order to utilize the thermal inertia of a hearth and reduce temperature fluctuation and energy consumption loss caused by frequent replacement of strip steel specifications, the production plan generally carries out centralized production of steel coils of the same type and specification. The production plan can keep the furnace temperature stable at the optimal steady-state operating point to the maximum extent. "Steady state operating point" is a common term in the art of process control and refers to a set of stable operating conditions corresponding to when the time rates of change of the main manipulated and controlled variables approach to stability and the system materials and energy costs reach dynamic equilibrium after an industrial plant is continuously operated for a period of time given the production load, feedstock properties, and process constraints. The steady state operating point is typically characterized by a steady state value of a key process parameter, which is the target operating condition for maintenance and optimization of the process control system. However, in actual production, the ideal steady-state operating point is often difficult to maintain continuously. Due to the inherent instability of the combustion system, the fluctuation of the ambient temperature and the air pressure, the dynamic change of the composition and the pressure of the protective atmosphere in the furnace, the complex coupling of factors such as the thermal inertia of the furnace body and the heat dissipation loss, even if the control system tries to maintain all the process parameters at the set values, the whole heating system in the furnace is difficult to maintain absolute balance. This dynamic imbalance causes the actual operating conditions to deviate slowly from the original set point, thus exhibiting a "steady state operating point drift". This steady state operating point drift, unlike a well-defined, rapid disturbance, tends to be a directional, cumulative, slow evolution process with a slowly varying characteristic over time (slow time varying characteristic). This is due to the fact that such drift occurs in connection with furnace lining heat accumulation, equipment performance gradients, environmental fluctuations, small drifts of sensors and actuators, etc. Therefore, the steady-state operating point drift with the slow time-varying characteristic has strong concealment and potential, and is difficult to be discovered and effectively controlled by a conventional instant feedback control system (a feedback control system in a primary machine) in real time. The short term process parameters observed by the operator may remain within control, but their long term trends have been silently off-baseline. If the drift of the steady-state operating point is not detected or identified early, the gradual change of the product quality is caused, the plate temperature (outlet plate temperature) of the strip steel outlet gradually rises or slides down in the length direction, namely the heating temperature distribution is not uniform and consistent any more, the mechanical properties (such as hardness and elongation) or key electromagnetic properties (such as iron loss and magnetic induction intensity) of the same type of strip steel in the length direction are not uniform and consistent any more, the head-tail property difference or the whole coil property slowly slides down, and even a large number of hidden inferior products with non-compliance performance are produced in serious cases. Meanwhile, the monitoring and processing means of the existing industrial field for steady-state operating point drift are still limited. The method generally adopted at present mainly comprises the steps of empirically judging through trend curves such as temperature of each measuring point in a furnace, opening of a combustion valve, strip steel speed and the like,