A method and system for controlling humidification of hot-dip galvanizing furnace nose for dew point assistance

Abstract

The present application relates to the technical field of heat treatment of metals, and specifically to a method and system for controlling humidification of a furnace nose for hot-dip galvanizing assisted by dew point, the method comprising: obtaining the furnace nose dew point, RCS segment dew point and ES segment dew point, heating temperature and wet nitrogen flow rate at each sampling moment and multiple moments before the furnace nose; determining the dew point fluctuation difference and dew point fluctuation index at each sampling moment; determining the dew point trend amount and humidification coefficient at each sampling moment; determining the control parameters of the PID control algorithm at each sampling moment; correcting the furnace nose dew point at each sampling moment, combining the PID control algorithm, determining the humidity control amount at each sampling moment, determining the valve opening at each sampling moment, and controlling the humidity in the furnace nose. The present application can accurately control the humidification of the furnace nose, and improve the accuracy of the dew point control of the furnace nose.

Description

Technical Field

[0001] The present application relates to the technical field of heat treatment of metals, and in particular to a method and system for controlling humidification of a furnace nose for hot-dip galvanizing with dew point assistance. Background Art

[0002] With the development of various industrial industries, higher requirements are placed on the performance of metal materials. Hot-dip galvanized alloyed steel plates are favored by various industrial products for their excellent corrosion resistance and good strength. However, zinc ash is inevitably produced during the hot-dip galvanizing process, which affects the quality of galvanized products.

[0003] The existing technology suppresses the generation of zinc ash by configuring a furnace nose humidification control system in the hot-dip galvanizing process. However, when the PID control is performed on the furnace nose dew point, the PID parameters are fixed. When the set parameters are large, the error can be quickly adjusted, but the system adjustment will also cause oscillation. This oscillation causes dew point instability, which may cause zinc ash to be generated, and also affect the dew point of the fast cooling section and the outlet section of the annealing furnace, thereby causing leakage defects. When the parameters are small, the response speed to the error is slow, thereby affecting the generation of zinc ash and the ZnO film on the surface of the zinc liquid. In addition, since the ZnO film on the surface of the zinc liquid is easy to break, the continued slow response will affect the generation of the ZnO film, thereby having a greater impact on the quality of galvanizing. How to perform PID control in a complex hot-dip galvanizing production environment so that it can respond to dew point errors quickly and generate ZnO films, while minimizing dew point oscillation and the impact on dew points at other locations is a key issue. Summary of the invention

[0004] In order to solve the above technical problems, a method and system for humidifying a hot-dip galvanizing furnace nose for dew point assistance are provided to solve the existing problems.

[0005] The solution to the technical problem of the present application is to provide a method and system for controlling humidification of a hot dip galvanizing furnace nose for dew point assistance, comprising the following steps:

[0006] In a first aspect, an embodiment of the present application provides a method for controlling humidification of a hot-dip galvanizing furnace nose for dew point assistance, the method comprising the following steps:

[0007] The furnace nose dew point, RCS segment dew point, ES segment dew point, heating temperature and wet nitrogen flow rate at each sampling moment and the previous multiple moments in the furnace nose are recorded as a historical reference set at each sampling moment;

[0008] According to the difference of furnace nose dew point at different moments in the historical reference set and the difference of furnace nose dew point trend change at adjacent moments, the dew point fluctuation difference at each collection moment is determined, the deviation degree of furnace nose dew point change trend at all moments in the historical reference set is analyzed, and the dew point fluctuation index at each collection moment is determined in combination with the dew point fluctuation difference;

[0009] Determine the dew point trend quantity at each collection moment according to the change trend of the dew point of the RCS segment and the dew point of the ES segment in the historical reference set; analyze the discrete degree of the heating temperature and the wet nitrogen flow rate at all times in the historical reference set, the fluctuation range of the dew point of the RCS segment and the ES segment at all times, and the correlation between the change of the heating temperature and the wet nitrogen flow rate and the dew point of the RCS segment and the dew point of the ES segment, and determine the humidification coefficient at each collection moment in combination with the dew point fluctuation index and the dew point trend quantity;

[0010] Based on the humidification coefficient, the control parameters of the PID control algorithm at each collection moment are determined; based on the dew point trend quantity, the dew point of the furnace nose at each collection moment is corrected, and combined with the PID control algorithm, the humidity control quantity at each collection moment is determined; based on the humidity control quantity, the valve opening at each collection moment is determined to control the humidity in the furnace nose.

[0011] Preferably, determining the dew point fluctuation difference at each acquisition moment includes:

[0012] The difference between the furnace nose dew point at each moment in the historical reference set and the normalized preset control dew point is recorded as the dew point difference at each moment;

[0013] Calculate the difference between the dew point difference at each moment in the historical reference set and its adjacent moment, and record it as the first difference at each moment;

[0014] Recording the absolute value of the ratio between each moment in the historical reference set and the first difference between each moment and its adjacent moment as the first absolute value of each moment;

[0015] The sum of the first absolute values ​​at all times in the historical reference set at each collection time is taken as the dew point fluctuation difference at each collection time.

[0016] Preferably, determining the dew point fluctuation index at each acquisition moment includes:

[0017] Respectively counting the number of the first difference values ​​in the historical reference set that are greater than or equal to 0 and the number of the first difference values ​​that are less than 0, and recording them as the positive value number and the non-positive value number;

[0018] The absolute value of the difference between the non-positive number and the positive number is used as the trend difference at each acquisition moment;

[0019] The ratio between the trend difference and the dew point fluctuation difference is used as the dew point fluctuation index at each collection moment.

[0020] Preferably, determining the dew point trend quantity at each acquisition moment includes:

[0021] An anomaly detection algorithm is used to perform anomaly detection on the RCS segment dew point and the ES segment dew point at all times in the historical reference set, and the abnormal dew points in the RCS segment dew point and the ES segment dew point at each acquisition time are obtained; all the abnormal dew points are eliminated, and the sequence to be fitted of the RCS segment and the sequence to be fitted of the ES segment at each acquisition time are obtained respectively;

[0022] Based on the sequence to be fitted, a fitting straight line of the RCS segment and a fitting straight line of the ES segment at each acquisition moment are obtained respectively;

[0023] The average of the slope of the fitting straight line of the RCS segment and the slope of the fitting straight line of the ES segment is taken as the dew point trend quantity at each collection moment.

[0024] Preferably, the determining of the humidification coefficient at each collection moment includes:

[0025] Calculate the discrete degrees of the heating temperature and the wet nitrogen flow rate at all times in the historical reference set at each collection time, record them as the first discrete degree and the second discrete degree; take the average of the first discrete degree and the second discrete degree as the fluctuation coefficient at each collection time;

[0026] Analyze the correlation between the heating temperature, wet nitrogen flow rate, RCS segment dew point, and ES segment dew point at all times in the historical reference set, as well as the extreme changes in all RCS segment dew points and ES segment dew points at all times, and determine the temperature and humidity impact index at each collection time;

[0027] The dew point fluctuation index, the dew point trend value and the fluctuation variation coefficient are fused, and the ratio of the fusion result to the temperature and humidity influence index is determined as the humidification coefficient at each collection moment.

[0028] Preferably, determining the temperature and humidity impact index at each collection moment includes:

[0029] Calculate the correlation between the heating temperature and wet nitrogen flow rate at all times in the historical reference set and the RCS segment dew point and ES segment dew point at all times, and use the maximum correlation as the dew point correlation coefficient at each collection time;

[0030] Calculate the ratio of the minimum and maximum values ​​of the dew points of all RCS segments and ES segments at all times in the historical reference set as the extreme fluctuation degree at each acquisition time;

[0031] The difference between the preset threshold and the dew point correlation coefficient is calculated, and the sum of the difference and the extreme fluctuation degree is used as the temperature and humidity impact index at each collection moment.

[0032] Preferably, the step of determining the control parameters of the PID control algorithm at each acquisition moment includes:

[0033] No. The proportional coefficient of the PID control algorithm at each acquisition moment The calculation formula is: ,in, For the The proportional coefficient of the PID control algorithm set at each acquisition moment, is the corresponding collection time, To preset the initial scale factor, For the The humidification coefficient at each collection moment, For the Humidification coefficient at each collection moment;

[0034] Based on the preset initial integral coefficient and the preset initial differential coefficient, the integral coefficient and differential coefficient of the PID control algorithm at each acquisition moment are determined using the same method as the proportional coefficient of the PID control algorithm at each acquisition moment.

[0035] Preferably, determining the humidity control amount at each collection moment includes:

[0036] No. Corrected furnace nose dew point at the sampling time The calculation formula is: ,in, For the The dew point of the furnace nose at the time of collection, For the Dew point trend quantity at each collection moment;

[0037] Based on the corrected furnace nose dew point at each collection moment, the preset control dew point, and the control parameters, a PID control algorithm is used to obtain the humidity control amount at each collection moment.

[0038] Preferably, the valve opening at each acquisition moment is calculated by the formula: ,in, For the The valve opening at the time of collection, For the The humidity control value at each collection moment, is an exponential function with a natural constant as its base.

[0039] In the second aspect, an embodiment of the present application also provides a dew point assisted hot dip galvanizing furnace nose humidification control system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, the steps of any one of the above-mentioned methods for dew point assisted hot dip galvanizing furnace nose humidification control are implemented.

[0040] This application has at least the following beneficial effects:

[0041] The present application determines the dew point fluctuation difference at each collection moment according to the difference in the dew point of the furnace nose at different moments in the historical reference set and the difference in the trend change of the dew point of the furnace nose at adjacent moments, analyzes the degree of deviation of the dew point change trend of the furnace nose at all moments in the historical reference set, and determines the dew point fluctuation index at each collection moment in combination with the dew point fluctuation difference. The application has the beneficial effect of taking into account the fluctuation change of the dew point of the furnace nose to reflect the stability of the dew point inside the furnace nose, so as to subsequently accurately control the dew point inside the furnace nose; determining the dew point trend amount at each collection moment; and determining the humidification coefficient at each collection moment. The application has the beneficial effect of analyzing the change trend of the dew point of the RCS section and ES section of the annealing furnace, as well as the changes in the heating temperature and the wet nitrogen flow rate, and combining the correlation between the dew point of the RCS section and the ES section and the heating temperature and the wet nitrogen flow rate. , to reflect the influence of humidity changes in the furnace nose on the dew point of the RCS segment and ES segment. Secondly, the humidification coefficient reflects the influence of the humidity of the furnace nose on the quality of hot-dip galvanizing; determine the control parameters of the PID control algorithm at each collection moment; correct the dew point of the furnace nose at each collection moment, and combine the PID control algorithm to determine the humidity control amount at each collection moment, determine the valve opening at each collection moment, and control the humidity in the furnace nose. Its beneficial effect is that the dew point of the furnace nose is corrected by the changes in the dew point of the RCS segment and ES, and the control parameters of the PID control algorithm are adjusted in real time through the humidification coefficient, so that the humidification of the furnace nose can be accurately controlled, which improves the accuracy of the dew point control of the furnace nose, helps to form ZnO film on the surface of zinc liquid, reduces the generation of zinc ash, and improves the quality of hot-dip galvanizing. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The following is a further detailed description of a dew point assisted hot dip galvanizing furnace nose humidification control method of the present application in conjunction with the accompanying drawings.

[0043] Figure 1 A flowchart of a method for controlling humidification of a hot-dip galvanizing furnace nose assisted by a dew point according to an embodiment of the present application;

[0044] Figure 2 A schematic diagram of the change of the dew point in the furnace nose over time provided in an embodiment of the present application;

[0045] Figure 3 A flowchart of the steps of a method for obtaining the dew point fluctuation index at each collection moment provided in an embodiment of the present application;

[0046] Figure 4 A flowchart of the steps of a method for obtaining a humidification coefficient at each collection moment provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the following is a further detailed description of a dew point assisted hot dip galvanizing furnace nose humidification control method and system proposed in the present application in combination with the accompanying drawings and implementation examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0048] Unless defined otherwise, 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.

[0049] See also Figure 1 , which shows a flow chart of a method for controlling humidification of a hot-dip galvanizing furnace nose for dew point assistance provided by an embodiment of the present application, the method comprising the following steps:

[0050] Step 1, record the furnace nose dew point, RCS segment dew point and ES segment dew point, heating temperature and wet nitrogen flow rate at each collection moment in the furnace nose and multiple moments before that as a historical reference set for each collection moment.

[0051] The closed area used to connect the annealing furnace and the hot-dip galvanizing pot is called the furnace nose. In order to avoid the evaporation and condensation of the zinc liquid, which will cause a large amount of zinc ash to be deposited in the furnace nose and on the surface of the zinc liquid, wet nitrogen is sprayed into the furnace nose. The moisture in the wet nitrogen reacts with the zinc liquid to form a layer of zinc oxide film on the surface of the zinc liquid in the furnace nose, thereby inhibiting the evaporation of the zinc liquid and controlling the generation of zinc ash.

[0052] Dew point meters are installed at the nose position of the hot-dip galvanizing unit, the rapid cooling section (Rapid Cooling Section, RCS section) and the exit section (ES section) of the annealing furnace, respectively, to measure the dew points at the nose position, RCS section and ES section, and obtain the nose dew point, RCS section dew point and ES section dew point, wherein the dew point refers to the gas temperature when the gas is saturated with water vapor; a temperature sensor is installed at the desalted water tank to measure the heating temperature of the desalted water tank; a gas flow meter is installed at the wet nitrogen inlet to measure the input flow rate of the wet nitrogen, thereby synchronously collecting data at each collection moment through various measuring instruments, and the collection time interval is t, and all the collected data are normalized and arranged in order of collection time, so as to obtain the nose dew point, RCS section dew point and ES section dew point, heating temperature and wet nitrogen flow rate at each collection moment.

[0053] Preferably, in this embodiment, the collection time interval is 5s. As other implementation modes, the implementer can set it according to the actual situation. Secondly, the maximum and minimum value normalization method is used for normalization. As other implementation modes, the implementer can adopt other methods of the prior art, such as Z-score normalization method, etc. This embodiment does not impose any special restrictions on this.

[0054] The furnace nose dew point, RCS segment dew point, ES segment dew point, heating temperature and wet nitrogen flow rate at each sampling moment and the previous multiple moments in the furnace nose are recorded as a historical reference set at each sampling moment;

[0055] Preferably, in this embodiment, the furnace nose dew point, RCS segment dew point, ES segment dew point, heating temperature and wet nitrogen flow rate at each collection moment and all moments within 1 hour before it are recorded as the historical reference set for each collection moment. As other implementation modes, the implementers can set them according to the actual situation. It should be noted that if there is a collection moment before which all the collection moments are less than 1 hour, mean filling is used to complete them. The implementers can also use other filling algorithms in the prior art to fill them.

[0056] At this point, the historical reference set for each collection moment is obtained.

[0057] Step 2, according to the difference of furnace nose dew point at different times in the historical reference set and the difference of furnace nose dew point trend at adjacent times, determine the dew point fluctuation difference at each collection time, analyze the deviation degree of furnace nose dew point change trend at all times in the historical reference set, and determine the dew point fluctuation index at each collection time in combination with the dew point fluctuation difference.

[0058] In the hot-dip galvanizing process, in order to reduce the generation of zinc ash, it is necessary to suppress the volatilization of zinc liquid and reduce the condensation of zinc vapor into zinc ash. Usually, the dew point of the furnace nose in the hot-dip galvanizing production line is controlled so that a ZnO film is generated on the surface of the zinc liquid to block the volatilization of the zinc liquid. Therefore, the control of the dew point of the furnace nose is very important. When the dew point of the furnace nose area is low, the content of wet nitrogen added is insufficient, so that the generated ZnO film cannot effectively isolate the volatilization of zinc liquid, and thus cannot effectively reduce the generation of zinc ash; when the dew point of the furnace nose area is too high, the content of wet nitrogen added in the furnace nose area is large. Although it can effectively reduce the generation of zinc ash, because the furnace nose is connected to the annealing furnace, the excess wet nitrogen will flow to the annealing furnace chamber, thereby affecting the dew point of the RCS section and the ES section, and then causing leakage defects.

[0059] Dew point refers to the gas temperature when the gas is saturated with water vapor. The amount of water vapor that the air can hold is limited, so the dew point in the furnace nose will not increase infinitely with the increase of wet nitrogen. When the water vapor content in the air in the furnace nose reaches the saturation point, the dew point will not continue to increase. Based on the above analysis, it is necessary to control the dew point of the furnace nose to be stable. The preset control dew point set for the furnace nose makes the actual dew point of the furnace nose stable to the preset control dew point. However, due to gas flow rate and uniformity, the dew point in the furnace nose will fluctuate around the preset control dew point. Therefore, when performing furnace nose dew point control, if the monitored actual dew point of the furnace nose fluctuates around the preset control dew point, it means that the actual dew point is close to the preset control dew point and more stable control is required.

[0060] When the difference between the actual dew point and the preset control dew point is large, the actual dew point gradually approaches the preset control dew point through dew point control, so the difference between the actual dew point and the preset control dew point is monotonic. Therefore, according to the change trend and fluctuation degree of the actual dew point relative to the preset control dew point, the size and stability of the furnace nose dew point can be measured.

[0061] Secondly, since the air in the furnace nose is relatively dry before the injection of wet nitrogen, the water vapor content in the air increases rapidly after the injection of wet nitrogen, and the dew point also rises rapidly; as the injection of wet nitrogen continues, the relative humidity inside the furnace nose gradually increases, and the increase in dew point gradually decreases; therefore, with the injection of wet nitrogen, the growth rate of the dew point in the furnace nose shows a trend of first fast and then slow.

[0062] Further, the schematic diagram of the change of the dew point in the furnace nose over time after the wet nitrogen is continuously injected is provided in the embodiment of the present application as shown in FIG. Figure 2 As shown, the horizontal axis is time and the vertical axis is the normalized dew point in the furnace nose.

[0063] Based on the above analysis, when the dew point is relatively stable, it will fluctuate around the preset control dew point, and the change speed is not monotonic. Therefore, analyzing the change speed of the dew point can determine the dew point stability and determine the dew point fluctuation index, which is:

[0064] The difference between the furnace nose dew point at each moment in the historical reference set and the normalized preset control dew point is recorded as the dew point difference at each moment;

[0065] Preferably, in this embodiment, the preset control dew point is -15°C. As other implementation methods, the implementer can set it according to the actual situation; the difference between the furnace nose dew point at each moment in the historical reference set and the normalized preset control dew point is recorded as the dew point difference at each moment.

[0066] Calculate the difference of the dew point difference between each moment in the historical reference set and its adjacent moment, record it as the first difference at each moment, and count the number of the first difference greater than or equal to 0 and the number of the first difference less than 0 in the historical reference set, record it as the positive value number and the non-positive value number;

[0067] The absolute value of the difference between the non-positive number and the positive number is used as the trend difference at each acquisition moment;

[0068] Recording the absolute value of the ratio between each moment in the historical reference set and the first difference between each moment and its adjacent moment as the first absolute value of each moment;

[0069] The sum of the first absolute values ​​at all moments in the historical reference set at each collection moment is taken as the dew point fluctuation difference at each collection moment;

[0070] The ratio between the trend difference and the dew point fluctuation difference is used as the dew point fluctuation index at each acquisition moment;

[0071] Preferably, in this embodiment, the calculation formula of the dew point fluctuation index at each collection moment is: ,in, For the The dew point fluctuation index at each collection moment, For the The difference between the number of times in the historical reference set of the collection time that the first difference is less than 0 and the number of times in which the first difference is greater than or equal to 0, For the The historical reference set of the collection time The first difference of the moments, For the The historical reference set of the collection time The first difference of the moments, For the The number of all moments in the historical reference set of the collection moment, To preset a value greater than 0 to avoid the denominator being 0, in this embodiment, The value is 0.01; is the first absolute value, is the dew point fluctuation difference.

[0072] It should be noted that when the dew point tends to be stable, the actual dew point will fluctuate around the preset control dew point, so that the dew point difference at all times in the historical reference set is not monotonic, so the first difference has both negative and non-negative values, and the trend difference is small; the dew point changes at adjacent moments are not monotonic, because the change between the dew point at the furnace nose at each moment and the preset control dew point is not fixed, so the first absolute value will not always be less than 1, the greater the dew point fluctuation difference will be, so when the dew point tends to be stable, the resulting dew point fluctuation index will be smaller, conversely, when the difference between the dew point and the preset control dew point is large, the dew point fluctuation index of the furnace nose is large, and the greater the difference, the greater the dew point fluctuation index.

[0073] Further, the step flow chart of the method for obtaining the dew point fluctuation index at each collection moment provided in the embodiment of the present application is as follows: Figure 3 shown.

[0074] At this point, the dew point fluctuation index at each collection moment is obtained.

[0075] Step 3, according to the change trend of the dew point of the RCS segment and the dew point of the ES segment in the historical reference set, determine the dew point trend quantity at each collection moment; analyze the discrete degree of the heating temperature and the wet nitrogen flow rate at all times in the historical reference set, and the fluctuation range of the dew point of the RCS segment and the ES segment at all times, as well as the correlation between the change of the heating temperature and the wet nitrogen flow rate and the dew point of the RCS segment and the dew point of the ES segment, and determine the humidification coefficient at each collection moment in combination with the dew point fluctuation index and the dew point trend quantity.

[0076] Based on the above analysis, the dew point fluctuation index of the furnace nose measures the fluctuation of the dew point of the furnace nose around the preset control dew point, but it only measures the change of the dew point of the furnace nose, and does not reflect the humidity in the furnace nose. Since the dew point of the furnace nose will not increase with the increase of wet nitrogen, when the furnace nose reaches saturation, the dew point of the furnace nose reaches a stable state. At this time, the dew point of the furnace nose is relatively stable, so that the dew point fluctuation index is also small. If the humidity in the furnace nose is too high at this time, the excess wet nitrogen will continue to flow into the annealing furnace chamber, affecting the dew point of the RCS section and the dew point of the ES section. This situation cannot be reflected by the dew point fluctuation index; or when the nitrogen flow rate and the temperature of the desalted water tank fluctuate, it will also cause the humidity in the furnace nose to change, thereby generating zinc ash. Based only on the dew point fluctuation index, it is impossible to judge the impact of the humidity stability in the furnace nose on the zinc ash.

[0077] Based on the above analysis, firstly, the abnormal characteristics of the dew point in the RCS segment and the ES segment are analyzed, specifically:

[0078] An anomaly detection algorithm is used to perform anomaly detection on the RCS segment dew point and the ES segment dew point at all times in the historical reference set, and the abnormal dew points in the RCS segment dew point and the ES segment dew point at each acquisition time are obtained; all the abnormal dew points are eliminated, and the sequence to be fitted of the RCS segment and the sequence to be fitted of the ES segment at each acquisition time are obtained respectively;

[0079] Preferably, in this embodiment, a LOF (Local Outlier Factor) anomaly detection algorithm is used for anomaly detection, wherein the LOF algorithm is a well-known technology and will not be described in detail herein.

[0080] The position number of each element in the sequence to be fitted of the RCS segment and its elements form a two-dimensional array;

[0081] Performing linear fitting on all two-dimensional arrays in the sequence to be fitted of the RCS segment to obtain the slope of the fitting straight line of the RCS segment at each acquisition moment;

[0082] The position number of each element in the sequence to be fitted of the ES segment and its elements form a two-dimensional array;

[0083] Perform linear fitting on all two-dimensional arrays in the sequence to be fitted of the ES segment respectively, and obtain the slope of the fitting line of the ES segment at each acquisition moment;

[0084] Preferably, in this embodiment, the least square method is used for curve fitting, wherein the least square method is a well-known technology and will not be described in detail here.

[0085] The average of the slope of the fitted straight line of the RCS segment and the slope of the fitted straight line of the ES segment at each acquisition moment is taken as the dew point trend quantity at each acquisition moment;

[0086] Preferably, in this embodiment, the calculation formula of the dew point trend quantity at each collection moment is: ,in, For the The dew point trend at each collection moment, For the The slope of the fitting line of the RCS segment at each acquisition moment, For the The slope of the fitting line of the ES segment at each acquisition moment.

[0087] It should be noted that the greater the slope of the fitting line, the greater the corresponding increasing trend. When the humidity in the furnace nose is too high, excess wet nitrogen will continue to flow into the annealing furnace chamber, or when the nitrogen flow rate or desalted water tank temperature fluctuations cause abnormal dew point, the dew point change trend can be described more accurately by eliminating outliers.

[0088] Further, based on the dew point trend quantity and the dew point fluctuation index, combined with the fluctuation of the heating temperature and the wet nitrogen flow rate, the humidification coefficient is determined to reflect the humidity of the furnace nose, specifically:

[0089] The discrete degrees of heating temperature and wet nitrogen flow rate at all times in the historical reference set at each acquisition time are calculated respectively, and recorded as the first discrete degree and the second discrete degree;

[0090] Preferably, in this embodiment, the variance of the heating temperature and the wet nitrogen flow rate at all times in the historical reference set of each collection moment is calculated respectively. As other implementation methods, the implementer can adopt other methods of the prior art, such as standard deviation, coefficient of variation, etc. This embodiment does not impose any special restrictions on this.

[0091] Taking the average of the first discreteness and the second discreteness as the fluctuation variation coefficient at each acquisition moment;

[0092] Calculate the correlation between the heating temperature and wet nitrogen flow rate at all times in the historical reference set and the RCS segment dew point and ES segment dew point at all times, and use the maximum correlation as the dew point correlation coefficient at each collection time;

[0093] Preferably, in this embodiment, the degree of correlation is measured by the Pearson correlation coefficient, wherein the calculation method of the Pearson correlation coefficient is a well-known technology and will not be repeated here. As other implementation methods, the implementer can adopt other methods of the prior art, such as the Spearman correlation coefficient, cosine similarity, etc., and this embodiment does not impose any special restrictions on this.

[0094] Calculate the ratio of the minimum and maximum values ​​of the dew points of all RCS segments and ES segments at all times in the historical reference set as the extreme fluctuation degree at each acquisition time;

[0095] Calculate the difference between the preset threshold and the dew point correlation coefficient, and use the sum of the difference and the extreme fluctuation as the temperature and humidity impact index at each collection moment;

[0096] Preferably, in this embodiment, the preset threshold value is 1. As other implementation modes, the implementer can set it according to the actual situation.

[0097] The dew point fluctuation index, the dew point trend value and the fluctuation change coefficient are integrated, and the ratio of the integrated result to the temperature and humidity influence index is determined as the humidification coefficient at each collection time;

[0098] It can be understood that the specific fusion relationship can be an addition relationship, a multiplication relationship, etc. The specific relationship is determined according to the actual scenario, and this embodiment does not impose any special restrictions on this.

[0099] Preferably, in this embodiment, the calculation formula of the humidification coefficient at each collection moment is: ,in, For the The humidification coefficient at each collection moment, For the The dew point fluctuation index at each collection moment, For the The dew point trend at each collection moment, For the The coefficient of variation of fluctuation at each collection moment, For the The dew point correlation coefficient at each collection time, For the The ratio of the minimum and maximum values ​​of the dew points of the RCS segment and the ES segment at all times in the historical reference set at a collection time. It is the temperature and humidity impact index.

[0100] It should be noted that when the humidity in the furnace nose makes the quality of hot-dip galvanizing worse, the humidity in the furnace nose is too high, thus affecting the dew point of the RCS section and the ES section. At this time, the dew point change trend of the RCS section and the ES section has a significant increase, that is, The dew point change of the RCS section and the ES section is related to the humidity of the furnace nose, and the humidity of the furnace nose is affected by the heating temperature and the wet nitrogen flow rate. Therefore, the dew point of the RCS section and the ES section also has a certain positive correlation with the heating temperature and the wet nitrogen flow rate, that is, the dew point correlation coefficient The larger the dew point fluctuation index is, the greater the impact on the quality of hot-dip galvanizing, and the more unstable the changes in heating temperature and wet nitrogen flow rate are, that is, the fluctuation coefficient The larger the value, the greater the possibility of zinc ash generation in the furnace nose, the greater the impact on the quality of hot-dip galvanizing, and the greater the dew point fluctuation in the RCS and ES sections. The smaller it is, the greater the impact on the quality of hot-dip galvanizing; the resulting humidification coefficient The larger the humidity is, the worse the quality of hot-dip galvanizing will be. On the contrary, when the humidity in the furnace nose is conducive to improving the quality of hot-dip galvanizing, the humidification coefficient is The smaller it is.

[0101] Further, the step flow chart of the method for obtaining the humidification coefficient at each collection moment provided in the embodiment of the present application is as follows: Figure 4 shown.

[0102] At this point, the humidification coefficient at each collection moment is obtained.

[0103] Step 4, based on the humidification coefficient, determine the proportional coefficient, integral coefficient and differential coefficient of the PID control algorithm at each collection moment; based on the dew point trend quantity, correct the dew point of the furnace nose at each collection moment, and determine the humidity control quantity at each collection moment in combination with the PID control algorithm; based on the humidity control quantity, determine the valve opening at each collection moment to control the humidity in the furnace nose.

[0104] Further, the parameters in the PID (proportion integration differentiation) control algorithm are adjusted. When the dew point of the furnace nose is significantly different from the preset control dew point, or affects the dew points of the RCS segment and the ES segment, a larger PID parameter is used to make the actual dew point of the furnace nose reach the preset control dew point as soon as possible, and minimize the impact on the dew points of the RCS segment and the ES segment; when the dew point of the furnace nose is near the preset control dew point, a smaller PID parameter is used to make the adjustment of the dew point of the furnace nose more stable. Thus, based on the humidification coefficient, the proportional coefficient in the PID (proportion integration differentiation) control algorithm is determined. , integral coefficient and the differential coefficient , specifically:

[0105] The proportional coefficient of the PID control algorithm at each acquisition moment is calculated as follows: ,in, For the The proportional coefficient of the PID control algorithm at each acquisition moment, For the The proportional coefficient of the PID control algorithm set at each acquisition moment, is the corresponding collection time, To preset the initial proportionality coefficient, in this embodiment, The value is 2. As other implementation methods, implementers can set it according to actual conditions; For the The humidification coefficient at each collection moment, For the Humidification coefficient at each collection moment.

[0106] It should be noted that the greater the humidification coefficient, the greater the negative impact of the humidity in the furnace nose on the quality of hot-dip galvanizing. At this time, the humidity in the furnace nose needs to be controlled as soon as possible to reduce the negative impact on the quality of hot-dip galvanizing. The greater the humidification coefficient at a moment compared to the previous moment, the sooner it needs to be adjusted. Is a positive number, the proportionality coefficient The larger the error, the faster the response and control adjustment. The smaller the humidification coefficient at a moment compared to the previous moment, the smaller the proportional coefficient will be. .

[0107] Based on the preset initial integral coefficient and the preset initial differential coefficient, the integral coefficient and the differential coefficient of the PID control algorithm at each acquisition moment are determined by the same method as the proportional coefficient of the PID control algorithm at each acquisition moment.

[0108] Preferably, when determining the integral coefficient and differential coefficient of the PID control algorithm at each acquisition moment, the preset initial integral coefficient value is 0.5, and the preset initial differential coefficient value is 0.5. As other implementation methods, the implementer can set them according to actual conditions.

[0109] Furthermore, when the water vapor content in the furnace nose reaches saturation, the measured value of the furnace nose dew point alone cannot reflect the influence of the dew points of the RCS and ES sections of the corresponding annealing furnace. Therefore, the furnace nose dew point is corrected based on the change trend of the dew points of the RCS and ES sections, specifically:

[0110] The corrected furnace nose dew point at each acquisition moment is calculated as follows: ,in, For the The corrected furnace nose dew point at the time of collection, For the The dew point of the furnace nose at the time of collection, For the Dew point trend quantity at each collection moment.

[0111] Based on the corrected furnace nose dew point at each collection moment, the preset control dew point, and the proportional coefficient, integral coefficient and differential coefficient of the PID control algorithm at each collection moment, the PID control algorithm is used to obtain the humidity control amount at each collection moment;

[0112] It should be noted that the PID control algorithm is a well-known technology and will not be described in detail here.

[0113] Furthermore, since the control of the humidity of the furnace nose is achieved by controlling the flow rate of the injected wet nitrogen, and the wet nitrogen flow rate is controlled by the valve of the wet nitrogen pipeline, the valve opening is determined based on the humidity control amount, specifically:

[0114] The valve opening at each sampling moment is calculated using the following formula: ,in, For the The valve opening at the time of collection, For the The humidity control value at each collection moment, is an exponential function with a natural constant as its base.

[0115] It should be noted that if the humidity control amount at each collection moment is less than or equal to 0, it means that the humidity of the furnace nose is conducive to improving the quality of hot-dip galvanizing, and there is no need to inject wet nitrogen into the furnace nose. If the humidity control amount at each collection moment is greater than 0, it means that the humidity of the furnace nose is not conducive to improving the quality of hot-dip galvanizing, and the humidity in the furnace nose needs to be increased. Therefore, the valve of the wet nitrogen pipeline needs to be opened; the value range of the valve opening is adjusted to , so that the output humidity control amount corresponds to the valve opening of the wet nitrogen pipeline, and the wet nitrogen flow rate is accurately controlled, thereby improving the quality of hot-dip galvanizing.

[0116] Based on the same inventive concept as the above method, an embodiment of the present application also provides a dew point-assisted hot-dip galvanizing furnace nose humidification 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, the steps of any one of the above-mentioned methods for dew point-assisted hot-dip galvanizing furnace nose humidification control are implemented.

[0117] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0118] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0119] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the present application. It should be pointed out that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the content of the technical solution of the present application, shall fall within the protection scope of the technical solution of the present application.

Claims

1. A method for controlling humidification of a hot dip galvanizing furnace nose for dew point assistance, characterized in that: The method comprises the following steps: The furnace nose dew point, RCS segment dew point, ES segment dew point, heating temperature and wet nitrogen flow rate at each sampling moment and the previous multiple moments in the furnace nose are recorded as a historical reference set at each sampling moment; According to the difference of furnace nose dew point at different moments in the historical reference set and the difference of furnace nose dew point trend change at adjacent moments, the dew point fluctuation difference at each collection moment is determined, the deviation degree of furnace nose dew point change trend at all moments in the historical reference set is analyzed, and the dew point fluctuation index at each collection moment is determined in combination with the dew point fluctuation difference; Determine the dew point trend quantity at each collection moment according to the change trend of the dew point of the RCS segment and the dew point of the ES segment in the historical reference set; analyze the discrete degree of the heating temperature and the wet nitrogen flow rate at all times in the historical reference set, the fluctuation range of the dew point of the RCS segment and the ES segment at all times, and the correlation between the change of the heating temperature and the wet nitrogen flow rate and the dew point of the RCS segment and the dew point of the ES segment, and determine the humidification coefficient at each collection moment in combination with the dew point fluctuation index and the dew point trend quantity; Based on the humidification coefficient, the control parameters of the PID control algorithm at each collection moment are determined; based on the dew point trend quantity, the furnace nose dew point at each collection moment is corrected, and the humidity control quantity at each collection moment is determined in combination with the PID control algorithm; based on the humidity control quantity, the valve opening at each collection moment is determined to control the humidity in the furnace nose; Determining the dew point fluctuation difference at each acquisition moment includes: The difference between the furnace nose dew point at each moment in the historical reference set and the normalized preset control dew point is recorded as the dew point difference at each moment; Calculate the difference between the dew point difference at each moment in the historical reference set and its adjacent moment, and record it as the first difference at each moment; Recording the absolute value of the ratio between each moment in the historical reference set and the first difference between each moment and its adjacent moment as the first absolute value of each moment; The sum of the first absolute values ​​at all moments in the historical reference set at each collection moment is taken as the dew point fluctuation difference at each collection moment; Determining the dew point fluctuation index at each acquisition moment includes: Respectively counting the number of the first difference values ​​in the historical reference set that are greater than or equal to 0 and the number of the first difference values ​​that are less than 0, and recording them as the positive value number and the non-positive value number; The absolute value of the difference between the non-positive number and the positive number is used as the trend difference at each acquisition moment; The ratio between the trend difference and the dew point fluctuation difference is used as the dew point fluctuation index at each acquisition moment; Determining the dew point trend quantity at each acquisition moment includes: An anomaly detection algorithm is used to perform anomaly detection on the RCS segment dew point and the ES segment dew point at all times in the historical reference set, and the abnormal dew points in the RCS segment dew point and the ES segment dew point at each acquisition time are obtained; all the abnormal dew points are eliminated, and the sequence to be fitted of the RCS segment and the sequence to be fitted of the ES segment at each acquisition time are obtained respectively; Based on the sequence to be fitted, a fitting straight line of the RCS segment and a fitting straight line of the ES segment at each acquisition moment are obtained respectively; The average of the slope of the fitting straight line of the RCS segment and the slope of the fitting straight line of the ES segment is used as the dew point trend quantity at each collection time; and the humidification coefficient at each collection time is determined, including: Calculate the discrete degrees of the heating temperature and the wet nitrogen flow rate at all times in the historical reference set at each collection time, record them as the first discrete degree and the second discrete degree; take the average of the first discrete degree and the second discrete degree as the fluctuation coefficient at each collection time; Analyze the correlation between the heating temperature, wet nitrogen flow rate, RCS segment dew point, and ES segment dew point at all times in the historical reference set, as well as the extreme changes in all RCS segment dew points and ES segment dew points at all times, and determine the temperature and humidity impact index at each collection time; Determining the temperature and humidity impact index at each collection moment includes: Calculate the correlation between the heating temperature and wet nitrogen flow rate at all times in the historical reference set and the RCS segment dew point and ES segment dew point at all times, and use the maximum correlation as the dew point correlation coefficient at each collection time; Calculate the ratio of the minimum and maximum values ​​of the dew points of all RCS segments and ES segments at all times in the historical reference set as the extreme fluctuation degree at each acquisition time; Calculate the difference between the preset threshold and the dew point correlation coefficient, and use the sum of the difference and the extreme fluctuation as the temperature and humidity impact index at each collection moment, wherein the preset threshold is 1; The dew point fluctuation index, the dew point trend value and the fluctuation change coefficient are integrated, and the ratio of the integrated result to the temperature and humidity influence index is determined as the humidification coefficient at each collection time; ,in, For the The humidification coefficient at each collection moment, For the The dew point fluctuation index at each collection moment, For the The dew point trend at each collection moment, For the The fluctuation coefficient of each acquisition moment, For the The dew point correlation coefficient at each collection time, For the The ratio of the minimum and maximum values ​​of the dew points of the RCS segment and the ES segment at all times in the historical reference set at a collection time. is the temperature and humidity impact index; The control parameters of the PID control algorithm at each acquisition moment are determined, including: No. The proportional coefficient of the PID control algorithm at each acquisition moment The calculation formula is: ,in, For the The proportional coefficient of the PID control algorithm set at each acquisition moment, is the corresponding collection time, is the preset initial scale factor, the value of the preset initial scale factor is 2. For the The humidification coefficient at each collection moment, For the Humidification coefficient at each collection moment; Based on the preset initial integral coefficient and the preset initial differential coefficient, the integral coefficient and differential coefficient of the PID control algorithm at each acquisition moment are determined using the same method as the proportional coefficient of the PID control algorithm at each acquisition moment.

2. A method for controlling humidification of a hot dip galvanizing furnace nose for dew point assistance according to claim 1, characterized in that: Determining the humidity control amount at each collection moment includes: No. Corrected furnace nose dew point at the sampling time The calculation formula is: ,in, For the The dew point of the furnace nose at the time of collection, For the Dew point trend quantity at each collection moment; Based on the corrected furnace nose dew point, the preset control dew point, and the control parameters at each collection moment, a PID control algorithm is used to obtain the humidity control amount at each collection moment.

3. A method for controlling humidification of a hot dip galvanizing furnace nose for dew point assistance according to claim 1, characterized in that: The valve opening at each acquisition moment is calculated by the following formula: ,in, For the The valve opening at the time of collection, For the The humidity control value at each collection moment, is an exponential function with a natural constant as its base.

4. A dew point assisted hot dip galvanizing furnace nose humidification 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, the steps of a method for controlling humidification of a hot-dip galvanizing furnace nose assisted by dew point are implemented as described in any one of claims 1 to 3.

Images