Annealing furnace pressure control method and system

Abstract

The application relates to the technical field of annealing furnace control, in particular to an annealing furnace pressure control method and system, which comprises the following steps: collecting pressure data in each furnace section of a continuous bright annealing furnace, temperature data of the furnace wall at each furnace section, and flow data at the outlet of a pressure regulating valve used at each furnace section; presetting an adjustment period of a proportional parameter in a PID controller used by the pressure regulating valve at each furnace section, obtaining each adjustment time of the proportional parameter; obtaining each synchronous change time of each furnace section in a time period between each adjustment time and an adjacent previous adjustment time, obtaining a pressure characteristic value of each furnace section at each adjustment time; obtaining a trend similarity characteristic value of each furnace section at each adjustment time; and obtaining the value of the proportional parameter in the PID controller in a time interval between each adjustment time and an adjacent next adjustment time, so as to control the furnace pressure in each furnace section. The application aims to improve the control precision of the furnace pressure.

Description

Technical Field

[0001] This application relates to the field of annealing furnace control technology, specifically to a method and system for controlling the furnace pressure of an annealing furnace. Background Technology

[0002] Continuous bright annealing furnaces, as a commonly used annealing furnace, alter the internal microstructure and properties of steel through heat treatment, thereby improving the steel's mechanical properties, plasticity, and toughness. During the heat treatment process in a continuous bright annealing furnace, a nitrogen-hydrogen mixture is typically introduced to maintain a reducing atmosphere, thus preventing oxidation of the steel during heat treatment. Simultaneously, to prevent outside air from entering the furnace and disrupting the reducing atmosphere, the pressure within each section of the continuous bright annealing furnace must be maintained above atmospheric pressure.

[0003] Existing technology calculates the weighted average pressure in all furnace sections and combines it with the pressure setpoint, using a PID (Proportional Integral Derivative) controller to control the opening of the pressure regulating valves used in each furnace section, thereby controlling the furnace pressure within each section. However, although this method treats the pressure in all furnace sections of a continuous bright annealing furnace as a whole to reduce the coupling effect between different furnace sections, the interconnection between furnace sections during the operation of the continuous bright annealing furnace leads to a delay in pressure transmission. In addition, fluctuations in furnace wall temperature and changes in flow rate at the outlet of the pressure regulating valve further cause hysteretic changes in the furnace pressure in each furnace section. This results in the furnace pressure in each furnace section of the continuous bright annealing furnace not responding promptly to the hysteretic changes caused by multiple factors, thus affecting the control accuracy of the furnace pressure in each furnace section. This leads to abnormal dew points in the continuous bright annealing furnace and damages the reducing atmosphere in the furnace, thereby affecting the annealing quality of the steel. Summary of the Invention

[0004] In view of the above, it is necessary to provide a furnace pressure control method and system for annealing furnaces, which improves the control accuracy of furnace pressure compared to a traditional furnace pressure control method and system.

[0005] In a first aspect, embodiments of this application provide a method for controlling the furnace pressure of an annealing furnace, the method comprising the following steps:

[0006] Real-time acquisition of pressure data, furnace wall temperature data, and flow rate data at the outlet of the pressure regulating valve used in each section of the continuous bright annealing furnace; preset adjustment cycle of the proportional parameter in the PID controller used by the pressure regulating valve in each section to obtain the adjustment time of the proportional parameter.

[0007] During the time period between each adjustment time and its adjacent previous adjustment time, by comparing the pressure data of each furnace segment with that of its adjacent furnace segments, the synchronous change time of each furnace segment within the time period is obtained. Combined with the difference between the pressure data of each furnace segment at its synchronous change time and that of its adjacent furnace segments, the pressure characteristic value of each furnace segment at each adjustment time is obtained.

[0008] By comparing the temporal trend similarity between the temperature data and flow data corresponding to each furnace segment within the time period, the trend similarity feature value of each furnace segment at each adjustment time is obtained.

[0009] By combining the pressure characteristic value and the trend similarity characteristic value with the preset upper limit and preset lower limit of the proportional parameter, the value of the proportional parameter in the PID controller is obtained within the time interval between each adjustment time and its adjacent next adjustment time, so as to control the furnace pressure in each furnace section.

[0010] In one embodiment, the process of obtaining the synchronization change time is as follows:

[0011] Within the time period, the difference between the pressure data in any furnace segment at each acquisition time and the pressure data in its adjacent preceding and following furnace segments is recorded as the preceding difference and the following difference for any furnace segment at each acquisition time. By comparing the sign of the preceding difference and the following difference, the synchronous change times of any furnace segment within the time period are obtained.

[0012] In one embodiment, the synchronization change time is the acquisition time when the previous difference and the subsequent difference have the same positive or negative sign.

[0013] In one embodiment, the pressure characteristic value is calculated as follows:

[0014] Within the time period, calculate the average of the previous difference and the next difference for each furnace section at all synchronous change moments;

[0015] Calculate the percentage of all synchronous change moments in each furnace segment within the time period out of all collected moments;

[0016] The pressure characteristic value can be further obtained by the mean and the quantity ratio.

[0017] In one embodiment, the pressure characteristic value is the product of the mean and the percentage of the quantity.

[0018] In one embodiment, the process of obtaining the trend similarity feature value is as follows:

[0019] The temperature and flow data corresponding to each furnace segment within the time period are arranged in chronological order to form the temperature sequence and flow sequence of each furnace segment at each adjustment time.

[0020] The trend terms of the temperature series and the flow rate series are extracted using a time series decomposition algorithm.

[0021] The difference between the trend term of the temperature series and the trend term of the flow rate series is calculated, and the trend similarity feature value can be further obtained through the difference.

[0022] In one embodiment, the trend similarity feature value is a normalized value of the reciprocal of the sum of the difference degree and a preset positive number.

[0023] In one embodiment, obtaining the value of the proportional parameter in the PID controller within the time interval between each adjustment time and its adjacent next adjustment time includes:

[0024] Calculate the average of the pressure characteristic value and the trend similarity characteristic value;

[0025] The difference between the preset upper limit value and the preset lower limit value is recorded as the change difference;

[0026] The values ​​of the proportional parameters in the PID controller at each adjustment time are obtained by using the preset lower limit, the average value, and the difference in change, and are used as the values ​​of the proportional parameters in the PID controller within the time interval.

[0027] In one embodiment, the process of obtaining the value of the proportional parameter in the PID controller at each adjustment time is as follows:

[0028] The product of the average value and the difference in change is calculated and rounded to the nearest whole number.

[0029] The sum of the calculation result and the preset lower limit value is used as the value of the proportional parameter in the PID controller at each adjustment time.

[0030] Secondly, embodiments of this application also provide an annealing furnace pressure control system, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any of the above-described annealing furnace pressure control methods.

[0031] This application has at least the following beneficial effects:

[0032] This application avoids the situation where the pressure in the furnace section is unstable due to the excessively frequent adjustment of the proportional parameter by setting the adjustment cycle of the proportional parameter. By obtaining the synchronous change time, it reflects the time node when the same pressure difference occurs between each furnace section and its adjacent furnace sections, and then calculates the pressure characteristic value to evaluate the magnitude and duration of the same pressure difference. This provides a key basis for the subsequent adjustment of the proportional parameter in the PID controller and helps to improve the response speed of the PID controller to the pressure lag caused by the pressure transmission between adjacent furnace sections.

[0033] Furthermore, by calculating trend similarity characteristic values, the similarity of the changing trends between temperature and flow rate is quantified, which helps to evaluate the synergistic effect of temperature and flow rate on furnace pressure. This provides a key basis for adjusting the proportional parameters in the PID controller and is conducive to improving the response speed of the PID controller to significant pressure hysteresis changes caused by the same changes in furnace wall temperature and flow rate.

[0034] Furthermore, by combining pressure characteristic values ​​with trend similarity characteristic values, dynamically adjusting the proportional parameter value in the PID controller can significantly improve the PID controller's response speed and control accuracy to changes in furnace pressure. This helps reduce pressure fluctuations caused by factors such as pressure transmission delay, temperature and flow rate changes, ensuring the stability of furnace pressure, avoiding abnormal dew point in the furnace and damage to the reducing atmosphere in the furnace, thereby improving the annealing quality of steel. Attached Figure Description

[0035] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0036] Figure 1 A flowchart illustrating the steps of an annealing furnace pressure control method according to one embodiment of this application;

[0037] Figure 2 This is a schematic diagram illustrating the process of adjusting the value of the proportional parameter. Detailed Implementation

[0038] In the description of the embodiments in this application, the words "exemplary," "or," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the words "exemplary," "or," and "for example" is intended to present the relevant concepts in a specific manner.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. It should be understood that, unless otherwise stated, " / " in this application means "or".

[0040] It should also be noted that the terms "first" and "second" in this application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0041] The following description, in conjunction with the accompanying drawings, details a specific scheme for an annealing furnace pressure control method and system provided in this application.

[0042] Please see Figure 1 The diagram illustrates a flowchart of a furnace pressure control method for an annealing furnace according to an embodiment of this application. The method includes the following steps:

[0043] Step 1: Real-time acquisition of pressure data, furnace wall temperature data, and flow rate data at the outlet of the pressure regulating valve used in each section of the continuous bright annealing furnace; preset the adjustment cycle of the proportional parameter in the PID controller used by the pressure regulating valve in each section to obtain the adjustment time of the proportional parameter.

[0044] Because the furnace sections are interconnected during the operation of a continuous bright annealing furnace, pressure changes are transmitted from one furnace section to another, resulting in pressure lag. Furthermore, fluctuations in furnace wall temperature affect the furnace pressure, and changes in flow rate at the outlet of the pressure regulating valve also cause pressure lag. Therefore, this application improves the response speed of the PID controller to lag changes caused by various factors by dynamically adjusting the proportional parameter values ​​of the PID controllers used in the pressure regulating valves of each furnace section, thereby ensuring the stability of the furnace pressure and improving the annealing quality of the steel.

[0045] Pressure data in each section of the continuous bright annealing furnace is collected in real time using pressure transmitters. The furnace sections include all heating sections, slow cooling sections, and final cooling sections. Temperature data of the furnace wall at each section of the continuous bright annealing furnace is collected in real time using temperature sensors. Flow data at the outlet of the pressure regulating valve used in each section of the continuous bright annealing furnace is collected in real time using flow meters.

[0046] In this embodiment, the sampling frequency of the pressure transmitter, temperature sensor and flow meter is 10Hz. The sampling frequency value is preset by the user and the implementer can set it according to the actual situation. This application does not impose any special restrictions.

[0047] The adjustment cycle of the proportional parameter in the PID controller used by the pressure regulating valves of each furnace section is preset to obtain the adjustment time of each proportional parameter.

[0048] In this embodiment, the length of the adjustment period is 5 seconds. The length of the adjustment period is preset by the user and can be set by the implementer according to the actual situation. This application does not impose any special restrictions.

[0049] Taking the t-th adjustment time as an example, the time interval between the t-th adjustment time and its adjacent previous adjustment time is taken as the adjustment interval of the t-th adjustment time. All pressure data, temperature data, and flow data within the adjustment interval of the t-th adjustment time are normalized to avoid the influence of different dimensions on subsequent processing.

[0050] In this embodiment, the Min-Max normalization method is used to normalize the pressure data, temperature data, and flow rate data respectively. The Min-Max normalization method is a well-known technology and will not be described in detail in this application.

[0051] Step 2: During the time period between each adjustment time and its adjacent previous adjustment time, by comparing the pressure data of each furnace segment with that of its adjacent furnace segments, obtain the synchronous change time of each furnace segment within the time period. Combine the difference between the pressure data of each furnace segment at its synchronous change time and that of its adjacent furnace segments, obtain the pressure characteristic value of each furnace segment at each adjustment time.

[0052] Because the sections of a continuous bright annealing furnace are interconnected, and gas typically flows from high pressure to low pressure, the following situations can occur when a pressure difference exists in the same direction between any section and its adjacent preceding and following sections: a positive pressure difference and a negative pressure difference. A positive pressure difference means that the pressure in any section is simultaneously higher than the pressure in its adjacent preceding and following sections. In this case, gas will diffuse from the section to its adjacent preceding and following sections, resulting in a decrease in the amount of gas and a drop in pressure in the section, while the amount of gas and the pressure in its adjacent preceding and following sections increase. A negative pressure difference means that the pressure in any section is simultaneously lower than the pressure in its adjacent preceding and following sections. In this case, gas will diffuse from its adjacent preceding and following sections into the section, resulting in an increase in the amount of gas and a rise in pressure in the section, while the amount of gas and the pressure in its adjacent preceding and following sections decrease. Therefore, when using a PID controller to control the pressure regulating valves used in each section of a continuous bright annealing furnace, the following processing is required to improve the response speed of the PID controller to pressure hysteresis changes caused by pressure transmission between adjacent furnace sections.

[0053] Within the adjustment interval at the t-th adjustment time, the difference between the pressure data in any furnace segment at each acquisition time and the pressure data in its adjacent preceding and following furnace segments is recorded as the preceding difference and the following difference for that furnace segment at each acquisition time. The acquisition times at which the preceding and following differences have the same sign are taken as the synchronous change times for that furnace segment within the adjustment interval at the t-th adjustment time. These times characterize the moments when the pressure data of that furnace segment and its two adjacent furnace segments form a pressure difference in the same direction within the adjustment interval at the t-th adjustment time. Specifically, "same sign" means both values ​​are negative or both are positive.

[0054] Furthermore, within the adjustment interval at the t-th adjustment time, the mean of the previous difference and the next difference corresponding to all synchronous change times of each furnace segment is calculated, and the proportion of all synchronous change times of each furnace segment in all acquisition times is calculated. The mean and the proportion are used to evaluate the magnitude and duration of the unidirectional pressure difference formed by the pressure data of each furnace segment and its two adjacent furnace segments within the adjustment interval at the t-th adjustment time. The product of the mean and the proportion is used as the pressure characteristic value of each furnace segment at the t-th adjustment time. A larger pressure characteristic value indicates a larger unidirectional pressure difference and a longer duration, resulting in a greater degree of pressure change within each furnace segment due to the unidirectional pressure difference. Therefore, when using a PID controller to control the pressure regulating valves used in each furnace segment, the proportional parameter should be larger to improve the PID controller's response speed to the pressure lag caused by pressure transmission between adjacent furnace segments. It should be noted that if a certain furnace section has only one adjacent furnace section, then within the adjustment interval at the t-th adjustment time, the average of the differences between the pressure data in the certain furnace section at all the collection times and the pressure data in its adjacent furnace section is taken as the pressure characteristic value of the certain furnace section at the t-th adjustment time.

[0055] Step 3: By measuring the temporal trend similarity between the temperature data and flow data corresponding to each furnace segment within the time period, obtain the trend similarity feature value of each furnace segment at each adjustment time.

[0056] During the operation of a continuous bright annealing furnace, the temperature of the furnace wall in each section typically varies due to changes in the power of the heating or cooling motors used in each section. The heat from the furnace wall surface is conducted into the furnace chamber, causing changes in the gas temperature and consequently, the pressure within the furnace. Furthermore, the flow rate at the outlet of the pressure regulating valve in each section also varies due to changes in the power of the gas supply system, leading to changes in the gas volume and, consequently, the pressure within the furnace. Therefore, when the furnace wall temperature and the flow rate at the outlet of the pressure regulating valve in a certain section of the continuous bright annealing furnace change simultaneously (e.g., both increase), the pressure in that section will change significantly due to the increase in gas temperature and volume. To improve the response speed of the PID controller to the significant pressure lag caused by the simultaneous changes in furnace wall temperature and flow rate in a particular section, the following processing is performed.

[0057] Within the adjustment interval at the t-th adjustment time, the temperature and flow data corresponding to each furnace section are arranged in time sequence to form the temperature sequence and flow sequence of each furnace section at the t-th adjustment time. The trend terms of the temperature sequence and the flow sequence are extracted by time series decomposition algorithm, respectively, to characterize the long-term change trend of the furnace wall temperature and the flow rate at the outlet of the pressure regulating valve of each furnace section within the adjustment interval at the t-th adjustment time, so as to reduce the influence of noise components in the collected temperature and flow data on the subsequent evaluation of whether the temperature and flow have the same change trend.

[0058] In this embodiment, the STL (Seasonal and Trend decomposition using Loess) time series decomposition algorithm is used to extract the trend terms of the temperature series and the flow rate series, respectively. The time series decomposition algorithm is a well-known technology and will not be described in detail in this application. As other implementation methods, based on the ability to extract the trend terms of the temperature series and the flow rate series, implementers may use other existing technologies, such as the X11 time series decomposition algorithm, the SEATS time series decomposition algorithm, etc. This application does not impose any special restrictions.

[0059] Furthermore, the difference between the trend term of the temperature sequence and the trend term of the flow rate sequence is calculated. The normalized value of the reciprocal of the sum of the difference and a preset positive number is used as the trend similarity feature value of each furnace segment at the t-th adjustment time. This value is used to evaluate whether the temperature and flow data corresponding to each furnace segment have the same trend within the adjustment interval at the t-th adjustment time. The larger the trend similarity feature value, the more similar the trend of the temperature and flow data corresponding to each furnace segment. Therefore, the pressure in each furnace segment may change significantly due to the similar trend of temperature and flow. Consequently, when using a PID controller to control the pressure regulating valves used in each furnace segment, the proportional parameter should be larger to improve the response speed of the PID controller to the significant pressure lag caused by the synchronous change of temperature and flow in the furnace segment. The preset positive number is used to avoid a denominator of 0. The value of the preset positive number is preset manually. In this embodiment, the preset positive number is 0.01.

[0060] In this embodiment, the difference between the trend term of the temperature sequence and the trend term of the flow rate sequence is specifically the DTW (Dynamic Time Warping) distance between them. The calculation of the DTW distance is a well-known technique and will not be elaborated upon here. As other implementation methods, based on the ability to measure the degree of difference between the elements of the trend term of the temperature sequence and the trend term of the flow rate sequence, the implementer may use other existing techniques, such as Euclidean distance, etc. This application does not impose any special restrictions.

[0061] In this embodiment, the sigmoid function is used to obtain the normalized value of the reciprocal of the sum of the difference degree and the preset positive number. The sigmoid function is a well-known technology and will not be described in detail in this application.

[0062] Step 4: By combining the pressure characteristic value and trend similarity characteristic value of each furnace section at each adjustment time with the preset upper limit and preset lower limit value of the proportional parameter, obtain the value of the proportional parameter in the PID controller used by the pressure regulating valve of each furnace section within the time interval between each adjustment time and the next adjacent adjustment time, so as to control the furnace pressure in each furnace section.

[0063] By combining the pressure characteristic values ​​and trend similarity characteristic values ​​of each furnace section at each adjustment time, and the preset upper and lower limits of the proportional parameter, the values ​​of the proportional parameters in the PID controllers used by the pressure regulating valves of each furnace section at each adjustment time are obtained. The expression is as follows:

[0064] In the formula, represents the value of the proportional parameter in the PID controller used by the pressure regulating valve of the a-th furnace section at the t-th adjustment time; p1 and p2 represent the preset upper limit and preset lower limit values ​​of the proportional parameter in the PID controller used by the continuous bright annealing furnace, respectively; round() represents the rounding function; This represents the average of the pressure characteristic value and the trend similarity characteristic value of the a-th furnace section at the t-th adjustment time. The values ​​of p1 and p2 can be determined using the critical proportionality method. In this embodiment, p1 and p2 are 0.1 and 1, respectively. The critical proportionality method is a well-known technique and will not be elaborated upon further in this application.

[0065] A PID (Proportional Integral Derivative) controller is used to control the opening of the pressure regulating valves used in each furnace section, thereby controlling the furnace pressure within each section. Specifically, the value of the proportional parameter in the PID controller used by the pressure regulating valve in the a-th furnace section at adjustment time t is used as the value of the proportional parameter in the PID controller used by the pressure regulating valve in the a-th furnace section within the adjustment interval at the next adjustment time. A schematic diagram of the proportional parameter adjustment process is shown below. Figure 2 As shown.

[0066] Based on the same inventive concept as the above method, this application embodiment also provides an annealing furnace pressure control system, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-described annealing furnace pressure control methods.

[0067] In summary, this application, by presetting the adjustment cycle of the proportional parameter, can avoid the situation where the pressure in the furnace section becomes unstable due to excessive adjustment of the proportional parameter; by obtaining the synchronous change time, it reflects the time node when the same-direction pressure difference occurs between each furnace section and its adjacent furnace sections, and then calculates the pressure characteristic value to evaluate the magnitude and duration of the same-direction pressure difference, providing a key basis for the subsequent adjustment of the proportional parameter in the PID controller, and helping to improve the response speed of the PID controller to the pressure lag caused by the pressure transmission between adjacent furnace sections;

[0068] Furthermore, by calculating trend similarity characteristic values, the similarity of the changing trends between temperature and flow rate is quantified, which helps to evaluate the synergistic effect of temperature and flow rate on furnace pressure. This provides a key basis for adjusting the proportional parameters in the PID controller and is conducive to improving the response speed of the PID controller to significant pressure hysteresis changes caused by the same changes in furnace wall temperature and flow rate.

[0069] Furthermore, by combining pressure characteristic values ​​with trend similarity characteristic values, dynamically adjusting the proportional parameter value in the PID controller can significantly improve the PID controller's response speed and control accuracy to changes in furnace pressure. This helps reduce pressure fluctuations caused by factors such as pressure transmission delay, temperature and flow rate changes, ensuring the stability of furnace pressure, avoiding abnormal dew point in the furnace and damage to the reducing atmosphere in the furnace, thereby improving the annealing quality of steel.

[0070] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0071] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from its essential characteristics. Therefore, the embodiments described above should be considered exemplary and non-limiting in all respects.

Claims

1. A method for controlling furnace pressure in an annealing furnace, characterized in that, The method includes the following steps: Real-time acquisition of pressure data, furnace wall temperature data, and flow rate data at the outlet of the pressure regulating valve used in each section of the continuous bright annealing furnace; preset adjustment cycle of the proportional parameter in the PID controller used by the pressure regulating valve in each section to obtain the adjustment time of the proportional parameter. During the time period between each adjustment time and its adjacent previous adjustment time, by comparing the pressure data of each furnace segment with that of its adjacent furnace segments, the synchronous change time of each furnace segment within the time period is obtained. Combined with the difference between the pressure data of each furnace segment at its synchronous change time and that of its adjacent furnace segments, the pressure characteristic value of each furnace segment at each adjustment time is obtained. By comparing the temporal trend similarity between the temperature data and flow data corresponding to each furnace segment within the time period, the trend similarity feature value of each furnace segment at each adjustment time is obtained. By combining the pressure characteristic value and the trend similarity characteristic value with the preset upper limit and preset lower limit of the proportional parameter, the value of the proportional parameter in the PID controller is obtained within the time interval between each adjustment time and its next adjacent adjustment time, so as to control the furnace pressure in each furnace section. The process of obtaining the synchronous change time is as follows: Within the time period, the difference between the pressure data in any furnace segment at each acquisition time and the pressure data in its adjacent preceding and following furnace segments is recorded as the preceding difference and the following difference for any furnace segment at each acquisition time. By comparing the sign of the preceding difference and the following difference, the synchronous change times of any furnace segment within the time period are obtained. The method for calculating the pressure characteristic value is as follows: Within the time period, calculate the average of the previous difference and the next difference for each furnace section at all synchronous change moments; Calculate the percentage of all synchronous change moments in each furnace segment within the time period out of all collected moments; The pressure characteristic value can be further obtained by the mean and the quantity ratio; The process for obtaining the trend similarity feature values ​​is as follows: The temperature and flow data corresponding to each furnace segment within the time period are arranged in chronological order to form the temperature sequence and flow sequence of each furnace segment at each adjustment time. The trend terms of the temperature series and the flow rate series are extracted using a time series decomposition algorithm. The difference between the trend term of the temperature series and the trend term of the flow rate series is calculated, and the trend similarity feature value can be further obtained through the difference. The step of obtaining the value of the proportional parameter in the PID controller within the time interval between each adjustment time and its adjacent next adjustment time includes: Calculate the average of the pressure characteristic value and the trend similarity characteristic value; The difference between the preset upper limit value and the preset lower limit value is recorded as the change difference; The values ​​of the proportional parameters in the PID controller at each adjustment time are obtained by using the preset lower limit, the average value, and the difference in change, and are used as the values ​​of the proportional parameters in the PID controller within the time interval. The synchronous change time is the acquisition time when the previous difference and the next difference have the same positive and negative sign; The pressure characteristic value is the product of the mean and the proportion of the quantity; The trend similarity feature value is the normalized value of the reciprocal of the sum of the difference degree and a preset positive number; The process of obtaining the values ​​of the proportional parameters in the PID controller at each adjustment time is as follows: The product of the average value and the difference in change is calculated and rounded to the nearest whole number. The sum of the calculation result and the preset lower limit value is used as the value of the proportional parameter in the PID controller at each adjustment time.

2. An annealing furnace pressure control system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the annealing furnace pressure control method as described in claim 1.

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