A desulfurization and denitrification control system and method under fluctuating working conditions of galvanizing flue gas

Abstract

The application relates to the technical field of desulfurization and denitrification control, in particular to a desulfurization and denitrification control system and method under fluctuating working conditions of galvanizing flue gas, which comprises the following steps: based on the difference between the pollutant concentration at the inlet of a treatment process at each moment and the pollutant concentration at the inlet of the treatment process at the next moment, and the pollutant concentration at the inlet of the treatment process, each desulfurization operation cycle is obtained by dividing the desulfurization process; the similarity index of the current working condition and each historical cycle is calculated, and the historical pollutant load is weighted and summed by taking the similarity index as the weight, so that the prediction value of the pollutant load at the current moment is obtained; according to the difference between the current pollutant load and the prediction value, the desulfurization degree and the adding experience of the similar historical cycle, the liquid alkali adding amount is dynamically corrected. The application can accurately predict the pollution load by matching similar historical working conditions, so that the adding amount of the medicament is self-adaptively regulated and controlled, and the desulfurization effect is improved.

Description

Technical Field

[0001] This application relates to the field of desulfurization and denitrification control technology, specifically to a desulfurization and denitrification control system and method under fluctuating galvanized flue gas conditions. Background Technology

[0002] During the desulfurization process of galvanizing, the pretreatment, zinc immersion, and post-treatment of the workpiece surface generate a large amount of flue gas containing pollutants such as sulfur dioxide. Because galvanizing production lines typically operate on a cyclical basis, involving steps such as workpiece removal, immersion, reaction, and re-removal, flue gas parameters, such as flow rate, temperature, and pollutant concentration, exhibit drastic, rapid, and cyclical fluctuations. These fluctuations pose a significant challenge to the stable operation of the flue gas treatment system and the efficient removal of pollutants.

[0003] Currently, most industrial desulfurization and denitrification control systems are based on fixed parameters or traditional PID control strategies. Under relatively stable flue gas parameters, these systems can meet emission requirements. However, under highly fluctuating conditions such as galvanizing flue gas, traditional control methods reveal significant shortcomings: during flue gas troughs, a fixed dosage of reagents can lead to overuse, wasting resources and potentially causing secondary pollution, such as equipment scaling or wastewater treatment problems due to excessive alkali. During peak periods, a fixed dosage of reagents cannot respond promptly to the sudden increase in pollutant concentration, resulting in decreased desulfurization efficiency and pollutant escape, making it difficult to meet increasingly stringent environmental emission standards and reducing the desulfurization effect. Summary of the Invention

[0004] To address the aforementioned technical problems, the purpose of this application is to provide a desulfurization and denitrification control system and method under fluctuating galvanized flue gas conditions. The specific technical solution adopted is as follows:

[0005] In a first aspect, embodiments of this application provide a desulfurization and denitrification control method under fluctuating galvanizing flue gas conditions, the method comprising the following steps:

[0006] The flue gas flow rate, flue gas temperature, and pollutant concentration at the inlet and outlet of the treatment process during the sequential desulfurization of the same batch of galvanized workpieces are acquired in real time, as well as the pH value of the desulfurization slurry during the desulfurization process.

[0007] Based on the difference in pollutant concentration at the inlet of the treatment process between each time point and its adjacent next time point, and the pollutant concentration at the inlet of the treatment process, the desulfurization process is divided into various desulfurization operation cycles.

[0008] Based on the flue gas flow rate and pollutant concentration at each time point, the pollutant load at each time point is determined; based on the difference in cycle length, flue gas temperature, and correlation coefficient of pollutant load between any two desulfurization operation cycles, the similarity index between any two desulfurization operation cycles is determined.

[0009] Based on the differences in pollutant load between the inlet and outlet of the treatment process at each time point, and the pH value of the circulating slurry at each time point, the degree of desulfurization at each time point is determined.

[0010] Based on the similarity index between the time period from the end of the nearest adjacent desulfurization operation cycle to the current time and any desulfurization operation cycle before the current time, as well as the pollutant load at each time point within any desulfurization operation cycle, the predicted value of the pollutant load at the current time is determined.

[0011] Based on the difference between the current pollutant load and its predicted value, as well as the degree of desulfurization, the control factor at the current moment is determined. Then, combined with the difference in liquid alkali dosage between the current moment and the corresponding moment in any previous desulfurization operation cycle, and the pollutant load at each moment in any desulfurization operation cycle, the liquid alkali dosage at the current moment is controlled.

[0012] Preferably, the division of the desulfurization process into various desulfurization operation cycles includes:

[0013] In the process of continuous desulfurization of the same batch of galvanized workpieces, the evaluation index at each time point is determined based on the difference in pollutant concentration at the inlet of the treatment process between each time point and the next adjacent time point, as well as the pollutant concentration at the inlet of the treatment process.

[0014] During the sequential desulfurization process of the same batch of galvanized workpieces, the average value of the evaluation index at all times is used as the segmentation threshold. The time when the evaluation index is greater than or equal to the segmentation threshold is recorded as the idle time. The time interval composed of all consecutive idle times is used as the idle period. The time period between the start time of each idle period and the start time of the next adjacent idle period is used as the desulfurization operation cycle.

[0015] Preferably, the method for determining the evaluation indicators at each time point is as follows:

[0016] During the sequential desulfurization process of the same batch of galvanized workpieces, the normalized value of the difference in pollutant concentration at the inlet of the treatment process between each time point and the next adjacent time point is calculated and multiplied by the pollutant concentration. The exponential function value with the natural constant as the base and the product of the product at each time point as the independent variable is used as the evaluation index at each time point.

[0017] Preferably, the pollutant load at each time point is the product of the pollutant concentration and the flue gas flow rate at each time point.

[0018] Preferably, the similarity index between any two desulfurization operation cycles is positively correlated with the correlation coefficient of the pollutant load between the two desulfurization operation cycles, and the similarity index between any two desulfurization operation cycles is negatively correlated with the difference in cycle length and the difference in flue gas temperature between the two desulfurization operation cycles.

[0019] Preferably, the method for determining the degree of desulfurization at each time point is as follows:

[0020] Calculate the proportion of the pH value of the circulating desulfurization slurry at each time point to the average pH value of the circulating desulfurization slurry at all times during its corresponding idle period, and record it as the acid-base characteristic value at each time point;

[0021] The degree of desulfurization at each time point is positively correlated with the difference in pollutant load between the inlet and outlet of the treatment process and the acid-base characteristic value at each time point.

[0022] Preferably, the expression for the predicted value of the pollutant load at the current moment is: In the formula, This represents the predicted pollutant load at the current moment. This represents the similarity index between the time period from the end of the nearest adjacent desulfurization operation cycle to the current time and the desulfurization operation cycle y before the current time. This represents the pollutant load at the same time point in the same sequence as the current time within the desulfurization operation cycle y; This represents the number of all moments within the desulfurization operation cycle y.

[0023] Preferably, the regulatory factor at the current moment includes:

[0024] Obtain the amount of liquid alkali added at each time point, calculate the normalized value of the difference between the pollutant load at the current time and its predicted value, and divide it by the normalized value of the desulfurization degree. This result is recorded as the characteristic value at the current time point.

[0025] The result of multiplying the normalized value of the liquid alkali dosage at the current moment by the characteristic value is used as the control factor at the current moment.

[0026] Preferably, the control of the liquid alkali dosage at the current moment includes:

[0027] Correction value for current liquid alkali dosage The expression is: In the formula, This indicates the amount of liquid alkali added before regulation, obtained at the current moment; This represents the regulatory factor at the current moment; This represents the difference in liquid alkali dosage between the current moment and any corresponding moment in the same order during any previous desulfurization operation cycle, as well as the adjustment factor obtained from the pollutant load at each moment in any desulfurization operation cycle. Secondly, embodiments of this application also provide a desulfurization and denitrification control system under fluctuating galvanized flue gas conditions, 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 the desulfurization and denitrification control method under fluctuating galvanized flue gas conditions described above.

[0028] This application has at least the following beneficial effects:

[0029] This application constructs an evaluation index that integrates the absolute level and rate of change of pollutant concentration, and uses the maximum inter-class variance algorithm to intelligently identify idle periods, thereby achieving precise and automated periodic division of the continuous desulfurization process. This method effectively solves the problem of blurred flue gas data boundaries caused by the periodic operation of galvanizing production, laying the foundation for subsequent adaptive control based on similar operating conditions and forward-looking prediction. Furthermore, to address the problem of inaccurate control caused by the variability of actual operating conditions, this application constructs a multi-dimensional similarity index. By comprehensively considering the similarity of pollutant load trends, cycle rhythms, and temperature histories, the similarity index can intelligently select the case that best matches the current operating conditions from massive historical data, thus providing a basis for the precise control of subsequent liquid alkali dosage. Furthermore, this application constructs a desulfurization degree index that integrates the actual amount of pollutants removed and the alkalinity reserve capacity of the slurry, achieving a precise quantitative evaluation of the actual effect of the alkali dosage strategy. This method not only focuses on "how much pollutant was removed" but also considers "under what reaction conditions it was removed," thus providing an objective and reliable evaluation standard for judging the merits of historical control strategies. Next, this application uses the similarity index between the current operating conditions and historical cases as weights to weight and fuse the pollutant load of multiple historical desulfurization operation cycles, thereby predicting the pollutant load. This method abandons the blindness of traditional predictions and realizes a prediction logic based on "the higher the similarity, the greater the reference value," providing a precise reference for controlling the liquid alkali dosage for pollution shocks. Finally, this application integrates forward-looking control factors and empirical adjustment factors, utilizing prediction differences to proactively predict pollution fluctuations, and introduces a directional adjustment mechanism based on desulfurization degree comparison. Ultimately, it generates an optimal solution for liquid alkali dosage that balances real-time response, future prediction, and historical wisdom, improving the accuracy of liquid alkali dosage during desulfurization and denitrification processes and enhancing desulfurization efficiency. Attached Figure Description

[0030] 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.

[0031] Figure 1 A flowchart illustrating the steps of a desulfurization and denitrification control method under flue gas fluctuation conditions in galvanizing, as provided in one embodiment of this application;

[0032] Figure 2 This is a flowchart illustrating the liquid alkali dosage control process according to one embodiment of this application. Detailed Implementation

[0033] To further illustrate the technical means and effects adopted by this application to achieve the intended purpose of the invention, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a desulfurization and denitrification control system and method under fluctuating galvanized flue gas conditions proposed in this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0034] 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 pertains.

[0035] The following, in conjunction with the accompanying drawings, details the specific scheme of the desulfurization and denitrification control system and method under fluctuating galvanized flue gas conditions provided in this application.

[0036] Please see Figure 1 The diagram illustrates a flowchart of a desulfurization and denitrification control method for galvanizing flue gas under fluctuating conditions, according to an embodiment of this application. The method includes the following steps:

[0037] Step S1: Real-time acquisition of flue gas flow rate, flue gas temperature, and pollutant concentration at the inlet and outlet of the treatment process during the sequential desulfurization of the same batch of galvanized workpieces, as well as the pH value of the desulfurization slurry during the desulfurization process.

[0038] To achieve precise control of the desulfurization process, this embodiment acquires in real time the flue gas flow rate, flue gas temperature, and pollutant concentration at the inlet and outlet of the treatment process during the sequential desulfurization of the same batch of galvanized workpieces, as well as the pH value of the circulating slurry during the desulfurization process. The flue gas flow rate is collected using a flow meter, the flue gas temperature is collected using a temperature sensor, and the pollutant concentration, i.e., sulfur dioxide concentration, is collected using an online flue gas analyzer. Simultaneously, a pH meter is used to monitor the pH value of the core reactant, i.e., the desulfurization slurry. The data acquisition frequency is 1Hz. In practical applications, as other implementation methods, the implementer can set the acquisition frequency according to specific circumstances; this embodiment does not impose any special limitations.

[0039] Step S2: Predict the current pollution load by matching the similarity of historical operating cycles, and evaluate the desulfurization efficiency in real time to adjust the amount of liquid alkali added in the desulfurization process.

[0040] The cyclical operation of galvanizing production lines results in dramatic dynamic fluctuations in their flue gas emissions. A single operation cycle comprises four phases: the idle period after the workpiece is removed (when flue gas parameters are at a trough), the intense reaction upon workpiece immersion (when pollutant concentration surges to a peak), the sustained high emissions during the immersion reaction period (when pollutant concentration begins to decline from its peak), and finally, a secondary small peak that may occur when the workpiece is removed. This cyclical pattern of "trough → peak → decline → trough" causes drastic and rapid changes in sulfur dioxide concentration in the flue gas, rendering traditional fixed-dosing strategies completely ineffective. During troughs, this leads to waste of reagents and the risk of secondary pollution, while during peaks, insufficient processing capacity causes pollutants to escape, failing to meet both environmental and economic requirements.

[0041] Therefore, this embodiment predicts the current pollution load by matching the similarity of historical operating cycles and evaluates the desulfurization efficiency in real time to adjust the amount of liquid alkali added during the desulfurization process. The flowchart of the liquid alkali addition adjustment process provided in this embodiment is as follows: Figure 2 As shown, the specific control process is as follows:

[0042] S2.1: Based on the difference in pollutant concentration at the inlet of the treatment process between each time point and its adjacent next time point, and the pollutant concentration at the inlet of the treatment process, the desulfurization process is divided into various desulfurization operation cycles.

[0043] First, this embodiment divides the desulfurization process into cycles based on the collected flue gas data, specifically:

[0044] In this embodiment, during the sequential desulfurization process of the same batch of galvanized workpieces, the evaluation index at each time point is determined based on the difference in pollutant concentration at the inlet of the treatment process between each time point and its adjacent subsequent time point, as well as the pollutant concentration at the inlet of the treatment process. Specifically, during the sequential desulfurization process of the same batch of galvanized workpieces, the normalized value of the difference in pollutant concentration at the inlet of the treatment process between each time point and its adjacent subsequent time point is calculated and multiplied by the pollutant concentration. The exponential function value with the natural constant as the base and the product of the product at each time point as the independent variable is used as the evaluation index at each time point.

[0045] Based on the evaluation indicators at each time point, it can be understood that the normalized value of the difference in pollutant concentration at the inlet of the treatment process between each time point and its adjacent next time point reflects the absolute level of pollutants. If the normalized value of the difference in pollutant concentration at the inlet of the treatment process between the current time point and its adjacent next time point is larger, and the pollutant concentration at the inlet of the treatment process at that time point is also larger, it indicates that the pollutant concentration at the current time point is relatively high. This contradicts the characteristic of low concentration during the idle period. Therefore, the smaller the corresponding evaluation indicator, the more it indicates that the current state does not conform to the characteristics of the idle period. Conversely, if the normalized value of the difference in pollutant concentration at the inlet of the treatment process between the current time point and its adjacent next time point is smaller, and the pollutant concentration at the inlet of the treatment process at that time point is also smaller, it indicates that the pollutant concentration at the current time point is not only low but also tends to be stable. This is highly consistent with the core characteristics of "low concentration and slow change" during the idle period. Therefore, the larger the corresponding evaluation indicator, the more it indicates that the current state highly conforms to the characteristics of the idle period.

[0046] Furthermore, during the sequential desulfurization process of the same batch of galvanized workpieces, the average value of the evaluation index at all times is used as the segmentation threshold. The time when the evaluation index is greater than or equal to the segmentation threshold is recorded as an idle time. The time interval composed of all consecutive idle times is used as the idle period. The time period between the start time of each idle period and the start time of the next adjacent idle period is used as the desulfurization operation cycle. Each desulfurization operation cycle completely includes the data of the entire process from the start of an idle period, through immersion, reaction, to the start of the next idle period.

[0047] It should be noted that there are many commonly used threshold segmentation algorithms. In this embodiment, the Otsu's inter-class variance algorithm is used to divide the desulfurization process into periods. In time-based applications, as other implementation methods, implementers may also use other threshold segmentation algorithms according to specific circumstances. This embodiment does not impose any special restrictions.

[0048] The process of dividing the desulfurization process using the Otsu's inter-class variance algorithm is a well-known technique and will not be elaborated further.

[0049] Thus, this embodiment constructs an evaluation index that integrates the absolute level and rate of change of pollutant concentration, and uses the maximum inter-class variance algorithm to intelligently identify idle periods, thereby achieving accurate and automated period division of the continuous desulfurization process. This method effectively solves the problem of blurred flue gas data boundaries caused by periodic operations in galvanizing production, laying the foundation for subsequent adaptive control based on similar operating conditions matching and forward-looking prediction.

[0050] S2.2: Determine the pollutant load at each time point based on the flue gas flow rate and pollutant concentration; determine the similarity index between any two desulfurization operation cycles based on the difference in cycle length, flue gas temperature, and correlation coefficient of pollutant load between any two desulfurization operation cycles.

[0051] Based on the above steps, the desulfurization process is initially divided into multiple independent desulfurization operation zones. However, since actual desulfurization is not an ideal mechanical cycle, variables such as workpiece size, shape, plating tank composition, and immersion speed will cause significant differences in the specific parameters of each desulfurization operation cycle. Therefore, directly using the parameters of historical desulfurization operation cycles to guide the real-time addition of liquid alkali will result in poor control effects due to mismatch with actual operating conditions. Therefore, this embodiment determines the pollutant load at each time point based on the flue gas flow rate and pollutant concentration; and determines the similarity index between any two desulfurization operation cycles based on the difference in cycle length, flue gas temperature, and correlation coefficient of pollutant load. This allows for intelligent matching of the most similar case from the changing historical operating conditions, thereby achieving precise control of the current liquid alkali addition. The specific process is as follows:

[0052] First, this embodiment determines the pollutant load at each time point based on the flue gas flow rate and pollutant concentration. Specifically:

[0053] The product of pollutant concentration and flue gas flow rate at each time point is used as the pollutant load at that time point to characterize the pressure exerted by pollutant concentration on the environment. If the pollutant load at the current time point is higher, it indicates that a large amount of pollutants are generated at that time, and more reagents are needed to ensure that emissions meet the standards. Conversely, if the pollutant load at the current time point is lower, it indicates that the total amount of pollutants generated at that time is less. If a high reagent dosage is still maintained at this time, it will cause unnecessary waste of resources and the risk of secondary pollution. Therefore, the reagent dosage should be reduced accordingly to achieve economic operation.

[0054] Furthermore, this embodiment determines the similarity index between any two desulfurization operation cycles based on the difference in cycle length, the difference in flue gas temperature, and the correlation coefficient of pollutant load between any two desulfurization operation cycles. Specifically:

[0055] In this embodiment, the similarity index between any two desulfurization operation cycles is positively correlated with the correlation coefficient of the pollutant load between any two desulfurization operation cycles, and the similarity index between any two desulfurization operation cycles is negatively correlated with the difference in cycle length and the difference in flue gas temperature between any two desulfurization operation cycles.

[0056] It should be noted that there are many methods to measure the difference between data. In this embodiment, the absolute difference in the cycle length between any two desulfurization operation cycles is taken as the difference in cycle length between any two desulfurization operation cycles. In actual application, as other implementation methods, implementers may also use other methods such as the square or ratio of the difference to measure the difference between data in combination with the specific situation. This embodiment does not impose any special restrictions on the selection of methods to measure the difference between data.

[0057] It should be noted that there are many methods to measure the differences between data groups. In this embodiment, the similarity index between any two desulfurization operation cycles and the DTW distance of the flue gas temperature at all times between any two desulfurization operation cycles are used as the similarity index between any two desulfurization operation cycles and the difference of the flue gas temperature between any two desulfurization operation cycles. In actual application, as other implementation methods, implementers can also set their own methods according to specific circumstances. This embodiment does not impose any special restrictions.

[0058] Furthermore, it should be noted that there are many methods for calculating the correlation coefficient between data sets. In this embodiment, the Pearson correlation coefficient of the pollutant load at all times between any two desulfurization operation cycles is used as the correlation coefficient between the flue gas temperature difference and the pollutant load between any two desulfurization operation cycles. In practical applications, as other implementation methods, implementers may also use Spearman correlation coefficient or Kendall's rank correlation coefficient or other correlation coefficient calculation methods according to specific circumstances. This embodiment does not impose any special restrictions on the selection of correlation coefficient calculation methods.

[0059] The calculation methods for DTW distance and Pearson correlation coefficient are well-known techniques, and their specific calculation processes will not be elaborated here.

[0060] It should be understood that a positive correlation means that the dependent variable increases as the independent variable increases, and the dependent variable decreases as the independent variable decreases. The specific relationship can be additive or multiplicative, etc., and is determined by the actual application. This application does not impose any special restrictions. A negative correlation means that the dependent variable decreases as the independent variable increases, and the dependent variable increases as the independent variable decreases. The relationship can be subtractive or divisive, etc., and is determined by the actual application.

[0061] Preferably, as one implementation method, in this embodiment, the expression for the similarity index between any two desulfurization operation cycles is: In the formula, This represents the similarity index between desulfurization operation cycle Q and desulfurization operation cycle W; This represents the correlation coefficient between the pollutant load between the desulfurization operation cycle Q and the desulfurization operation cycle W. This represents the normalized value of the difference in cycle length between the desulfurization operation cycle Q and the desulfurization operation cycle W. This represents the normalized value of the flue gas temperature difference between desulfurization operation cycle Q and desulfurization operation cycle W. This indicates a preset constant greater than 0, used to prevent the denominator from being 0. The value is set manually; in this embodiment, The value of is 0.01. Provided that the denominator is not zero and does not excessively affect the calculation result, the implementer may also set it according to the specific situation. This embodiment does not impose any special restrictions.

[0062] It should be noted that adding 1 to the numerator is to prevent the correlation coefficient from being less than 0. The normalization method in this embodiment uses the maximum-minimum normalization method to normalize the data. In practical applications, as other implementation methods, implementers can also use other normalization methods such as z-score standardization to normalize the data according to specific circumstances. This embodiment does not impose any special restrictions.

[0063] Among them, the maximum-minimum normalization method is a well-known technique, and the specific process of using it to normalize data will not be elaborated here.

[0064] Based on the similarity index between any two desulfurization operation cycles, it can be understood that the similarity index is used to quantify the comprehensive evaluation index of the similarity of operating conditions between two different desulfurization operation cycles. It is used to characterize the degree of similarity between historical operating conditions and current operating conditions in desulfurization mode. If the correlation coefficient of pollutant load between desulfurization operation cycle Q and desulfurization operation cycle W is larger, it indicates that the trend of pollutant load between desulfurization operation cycle Q and desulfurization operation cycle W is more similar. Therefore, the larger the similarity index, the more similar the operating conditions of desulfurization operation cycle Q and desulfurization operation cycle W are. At the same time, if the normalized value of the difference in cycle length between desulfurization operation cycle Q and desulfurization operation cycle W is smaller, it indicates that the rhythm difference between the two desulfurization operation cycles is smaller and the similarity is lower. Therefore, the corresponding similarity index is larger. In addition, if the normalized value of the difference in flue gas temperature between desulfurization operation cycle Q and desulfurization operation cycle W is smaller, it indicates that the temperature history between the two desulfurization operation cycles is more matched and the difference in chemical reaction is smaller. The corresponding similarity index is larger.

[0065] Conversely, the smaller the correlation coefficient of pollutant load between desulfurization operation cycle Q and desulfurization operation cycle W, the more mismatched their pollutant load change trends are, and the more significant the difference in their operating conditions. Therefore, the smaller the similarity index, the less similar their operating conditions are. At the same time, the larger the normalized value of the difference in cycle length between two desulfurization operation cycles, the greater the difference in their operating rhythms, making effective benchmarking difficult. Therefore, the smaller the corresponding similarity index is. In addition, the larger the normalized value of the difference in flue gas temperature between the two, the greater the difference in their chemical reaction environments, the lower the reference value of historical experience, and the smaller the corresponding similarity index is.

[0066] Thus, in order to solve the problem of inaccurate control caused by the variability of actual operating conditions, this embodiment constructs a multi-dimensional similarity index. By comprehensively considering the similarity of pollutant load trends, cycle rhythms and temperature history, the similarity index can intelligently select the case that best matches the current operating conditions from massive historical data, thereby providing a basis for the precise control of subsequent liquid alkali dosage.

[0067] S2.3: Determine the degree of desulfurization at each time point based on the difference in pollutant load between the inlet and outlet of the treatment process at each time point, and the pH value of the circulating slurry at each time point.

[0068] Furthermore, in this embodiment, the proportion of the pH value of the circulating desulfurization slurry at each time point to the average pH value of the circulating desulfurization slurry at all times during its corresponding idle period is calculated and recorded as the acid-base characteristic value at each time point.

[0069] The degree of desulfurization at each time point is positively correlated with the difference in pollutant load between the inlet and outlet of the treatment process and the acid-base characteristic value at each time point.

[0070] It should be noted that there are many methods to measure the differences between data. In this embodiment, the absolute difference between the pollutant load at the inlet and outlet of the treatment process at each time point is taken as the difference between the pollutant load at the inlet and outlet of the treatment process at each time point. In practical applications, as other implementation methods, implementers may also use other methods such as the square or ratio of the difference to measure the differences between data, depending on the specific circumstances. This embodiment does not impose any special restrictions on the selection of methods for measuring the differences between data.

[0071] Preferably, as one implementation method, in this embodiment, the product of the difference in pollutant load between the inlet and outlet of the treatment process at each time point and the acid-base characteristic value is taken as the desulfurization degree at each time point.

[0072] Based on the desulfurization degree at each time point, it can be understood that the desulfurization degree is a quantitative indicator used to evaluate the actual effect of the alkali addition strategy at a specific time. If the difference in pollutant load between the inlet and outlet of the treatment process is greater at the current time, and the acid-base characteristic value is larger, it indicates that more pollutants are removed at the current time, and the desulfurization effect is better. Therefore, the desulfurization degree is higher. Conversely, if the difference in pollutant load between the inlet and outlet of the treatment process is smaller at the current time, and the acid-base characteristic value is smaller, it indicates that the pollutants removed at the current time are limited, and the alkalinity reserve of the desulfurization slurry is insufficient or the reactivity is low. The desulfurization effect is worse, and therefore, the desulfurization degree is lower.

[0073] Thus, this embodiment achieves a precise quantitative evaluation of the actual effect of the alkali addition strategy by constructing a desulfurization degree index that integrates the actual amount of pollutants removed and the alkalinity reserve capacity of the slurry. This method not only focuses on "how many pollutants were removed" but also considers "under what reaction conditions they were removed", thereby providing an objective and reliable evaluation standard for judging the merits of historical control strategies.

[0074] S2.4: Based on the similarity index between the time period from the end time of the nearest adjacent desulfurization operation cycle to the current time and any desulfurization operation cycle before the current time, and the pollutant load at each time point within any desulfurization operation cycle, determine the predicted value of the pollutant load at the current time.

[0075] Based on the above steps, the degree of desulfurization at each moment within any desulfurization operation cycle was obtained, quantifying the control effect of desulfurization within the operation cycle. Therefore, based on historical desulfurization effects, this embodiment further determines the predicted value of pollutant load at the current moment based on the similarity index between the end time of the nearest adjacent desulfurization operation cycle before the current moment and any desulfurization operation cycle before the current moment, as well as the pollutant load at each moment within any desulfurization operation cycle. The liquid alkali dosage is adjusted according to the predicted pollutant load. The specific process is as follows:

[0076] As one implementation method, in this embodiment, the predicted value of the pollutant load at the current moment is... The expression is: In the formula, This represents the similarity index between the time period from the end of the nearest adjacent desulfurization operation cycle to the current time and the desulfurization operation cycle y before the current time. This represents the pollutant load at the same time point in the same sequence as the current time within the desulfurization operation cycle y; This represents the number of all moments within the desulfurization operation cycle y.

[0077] It should be noted that the similarity index between the time period from the end of the nearest adjacent desulfurization operation cycle to the current time and the desulfurization operation cycle y before the current time is calculated in the same way as in step S2.2. The only difference is the selection of the range. That is, a time period with the same length and the same time sequence position as the time period from the end of the nearest adjacent desulfurization operation cycle to the current time is extracted from the desulfurization operation cycle y before the current time, and the similarity index between the time period and the time period is calculated.

[0078] The predicted value of pollutant load at the current moment can be understood as a representation of the prediction of the upcoming pollution impact based on the matching of the current operating conditions and historical experience. If the similarity index between the time period from the end of the nearest adjacent desulfurization operation cycle to the current moment and the desulfurization operation cycle y before the current moment is greater, it means that the desulfurization operation cycle y is more similar to the current situation, the weight of the pollutant load corresponding to the desulfurization operation cycle y is greater, and the contribution of the pollutant load corresponding to the desulfurization operation cycle y to the final prediction result is more significant.

[0079] Conversely, if the similarity index between the time period from the end of the nearest adjacent desulfurization operation cycle to the current time and the desulfurization operation cycle y before the current time is smaller, it indicates that the desulfurization operation cycle y is more different from the current situation, and its historical data reference value is lower. Therefore, the weight of the pollutant load corresponding to the desulfurization operation cycle y is smaller, and its contribution to the final prediction result is weaker.

[0080] Thus, this embodiment uses the similarity index between the current operating conditions and historical cases as weights to perform weighted fusion of pollutant loads from multiple historical desulfurization operation cycles, thereby predicting pollutant loads. This method abandons the blindness of traditional predictions and realizes a prediction logic based on "the higher the similarity, the greater the reference value," providing a precise reference for the control of liquid alkali dosage for pollution impact.

[0081] S2.5: Based on the difference between the pollutant load at the current moment and its predicted value, as well as the degree of desulfurization, determine the control factor at the current moment, and combine the difference in liquid alkali dosage between the current moment and the corresponding moment in any previous desulfurization operation cycle, as well as the pollutant load at each moment in any desulfurization operation cycle, to control the liquid alkali dosage at the current moment.

[0082] In this embodiment, firstly, based on the difference between the current pollutant load and its predicted value, and the degree of desulfurization, the control factor at the current moment is determined. Specifically:

[0083] Obtain the amount of liquid alkali added at each time point, calculate the normalized value of the difference between the pollutant load at the current time and its predicted value, and divide it by the normalized value of the desulfurization degree. This result is recorded as the characteristic value at the current time point.

[0084] The result of multiplying the normalized value of the liquid alkali dosage at the current moment by the characteristic value is used as the control factor at the current moment.

[0085] Furthermore, this embodiment adjusts the liquid alkali dosage at the current moment based on the control factor at the current moment, combined with the difference in liquid alkali dosage between the current moment and any corresponding moment in the previous desulfurization operation cycle, as well as the pollutant load at each moment in any desulfurization operation cycle. Specifically, the liquid alkali dosage correction value at the current moment is as follows: The expression is: In the formula, This indicates the amount of liquid alkali added before regulation, obtained at the current moment; This represents the regulatory factor at the current moment; It represents the difference in liquid alkali dosage between the current moment and any corresponding moment in the previous desulfurization operation cycle, as well as the adjustment factor obtained from the pollutant load at each moment in any desulfurization operation cycle.

[0086] It should be noted that the specific calculation method for the adjustment factor is as follows:

[0087] Current adjustment factor The expression is: In the formula, This is the direction adjustment factor for the desulfurization operation cycle y at the current moment; This indicates the amount of liquid alkali added before the current adjustment. This indicates the amount of liquid alkali added at the current moment within the desulfurization operation cycle y. This represents the similarity index between the time period from the end of the nearest adjacent desulfurization operation cycle to the current time and the desulfurization operation cycle y before the current time. This represents the number of all moments within the desulfurization operation cycle y; norm() represents the normalization function.

[0088] The method for obtaining the direction adjustment factor is as follows: if the degree of desulfurization at the current moment is greater than or equal to the degree of desulfurization at the corresponding moment within the desulfurization operation cycle y, then f takes the value of 1; otherwise, f takes the value of -1.

[0089] Based on the current correction value of liquid alkali dosage, it can be understood that the correction value of liquid alkali dosage is affected by the control factor and the adjustment factor. The control factor gives the control system predictability, so that the dosage, i.e., the liquid alkali dosage, can respond to the fluctuation of pollution load in a timely manner. The adjustment factor selects the historical cases most relevant to the current working conditions through similarity index, and sets the direction adjustment factor by comparing the desulfurization degree, so as to learn from successful experience or avoid failure lessons.

[0090] Thus, this embodiment, by integrating forward-looking control factors and empirical adjustment factors, utilizes predictive differences to achieve proactive prediction of pollution fluctuations. Furthermore, it introduces a directional adjustment mechanism based on desulfurization degree comparison, ultimately generating an optimal solution for liquid alkali dosing that takes into account real-time response, future prediction, and historical wisdom. This improves the accuracy of liquid alkali dosing during desulfurization and denitrification processes and enhances desulfurization efficiency.

[0091] Based on the same inventive concept as the above method, this application embodiment also provides a desulfurization and denitrification control system under flue gas fluctuation conditions for galvanizing, 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 desulfurization and denitrification control methods under flue gas fluctuation conditions for galvanizing.

[0092] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, specific embodiments of this specification have been described above. Additionally, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing are possible or may be advantageous.

[0093] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0094] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. A desulfurization and denitrification control method for fluctuating operating conditions of galvanizing flue gas, characterized by, The method comprises the following steps: Real-time acquisition of the flue gas flow, flue gas temperature and pollutant concentration at the inlet and outlet of the treatment process, and the pH value of the desulfurization slurry during the continuous desulfurization process of the same batch of galvanized workpieces, respectively; Based on the difference between the pollutant concentration at the inlet of the treatment process at each time and the pollutant concentration at the inlet of the treatment process at the adjacent next time, and the pollutant concentration at the inlet of the treatment process, each desulfurization operation period is divided from the desulfurization process; Based on the flue gas flow and pollutant concentration at each time, the pollutant load at each time is determined; based on the period length difference, flue gas temperature difference and correlation coefficient of the pollutant load between any two desulfurization operation periods, the similarity index between any two desulfurization operation periods is determined; Based on the difference between the pollutant load between the inlet and outlet of the treatment process at each time, and the pH value of the circulating slurry at each time, the desulfurization degree at each time is determined; Based on the period from the end time of the adjacent nearest desulfurization operation period before the current time to the current time, the similarity index between any desulfurization operation period before the current time, and the pollutant load at each time in any desulfurization operation period, the predicted value of the pollutant load at the current time is determined; Based on the difference between the pollutant load at the current time and its predicted value, and the desulfurization degree, the regulation factor at the current time is determined, and the liquid alkali addition amount at the current time is regulated in combination with the difference between the liquid alkali addition amount at the same time of the same order between the current time and any desulfurization operation period before the current time, and the pollutant load at each time in any desulfurization operation period; The division of the desulfurization process to obtain each desulfurization operation period comprises: During the continuous desulfurization process of the same batch of galvanized workpieces, based on the difference between the pollutant concentration at the inlet of the treatment process at each time and the pollutant concentration at the inlet of the treatment process at the adjacent next time, and the pollutant concentration at the inlet of the treatment process, the evaluation index at each time is determined; During the continuous desulfurization process of the same batch of galvanized workpieces, the average value of the evaluation index at all times is taken as the segmentation threshold, the time when the evaluation index is greater than or equal to the segmentation threshold is recorded as the idle time, and the time interval composed of all continuous idle times is taken as the idle period; the period between the starting time of each idle period and the starting time of the adjacent next idle period is taken as the desulfurization operation period; The determination method of the evaluation index at each time is: During the continuous desulfurization process of the same batch of galvanized workpieces, the product of the normalized value of the difference between the pollutant concentration at the inlet of the treatment process at each time and the pollutant concentration at the inlet of the treatment process at the adjacent next time and the pollutant concentration is calculated; the exponential function value with the natural constant as the base number and the product at each time as the independent variable is taken as the evaluation index at each time.

2. The desulfurization and denitrification control method for fluctuating operating conditions of galvanizing flue gas according to claim 1, characterized in that, The pollutant load at each time is the product of the pollutant concentration and the flue gas flow at each time.

3. The desulfurization and denitrification control method for fluctuating operating conditions of a zinc plating flue gas according to claim 1, characterized in that, The similarity index between any two desulfurization operation periods is positively correlated with the correlation coefficient of the pollutant load between the any two desulfurization operation periods, and the similarity index between any two desulfurization operation periods is negatively correlated with the period length difference and the flue gas temperature difference between the any two desulfurization operation periods.

4. The desulfurization and denitrification control method for fluctuating operating conditions of a zinc plating off-gas as claimed in claim 1, characterized in that, The determination method of the desulfurization degree at each time point is: Calculate the proportion of the pH value of the circulating desulfurization slurry at each time point in the average pH value of the circulating desulfurization slurry at all time points in the corresponding idle period, and record it as the acid-base characteristic value at each time point. The desulfurization degree at each time point is positively correlated with the difference in pollutant load between the inlet and outlet of the treatment process at each time point and the acid-base characteristic value.

5. The desulfurization and denitrification control method for fluctuating operating conditions of a zinc plating off-gas as claimed in claim 1, characterized in that, The expression of the predicted value of the pollutant load degree at the current time is: ; in the formula, represents the predicted value of the pollutant load degree at the current time; represents the similarity index between the period from the end time of the adjacent nearest desulfurization operation cycle before the current time to the current time and the desulfurization operation cycle y before the current time; represents the pollutant load degree at the same time as the current time in the desulfurization operation cycle y; represents the number of all times in the desulfurization operation cycle y.

6. The desulfurization and denitrification control method for fluctuating operating conditions of a zinc plating off-gas according to claim 1, characterized in that, The control factor at the current time point comprises: Obtain the liquid alkali addition amount at each time point, calculate the normalized value of the difference between the pollutant load at the current time point and its predicted value, and the normalized value of the desulfurization degree, and record it as the characteristic value at the current time point. The product of the normalized value of the liquid alkali addition amount at the current time point and the characteristic value is taken as the control factor at the current time point.

7. The desulfurization and denitrification control method for fluctuating operating conditions of a zinc plating off-gas as claimed in claim 1, characterized by, The control of the liquid alkali addition amount at the current time point comprises: The expression of the correction value of the liquid caustic soda addition amount at the current time is: The expression of the correction value of the liquid caustic soda addition amount at the current time is: ; wherein, represents the liquid caustic soda addition amount obtained before the regulation at the current time; represents the regulation factor at the current time; represents the regulation factor obtained according to the difference of the liquid caustic soda addition amount between the current time and the same time of the corresponding order in any desulfurization operation cycle and the pollutant load at each time in any desulfurization operation cycle.

8. A desulfurization and denitrification control system under fluctuating conditions of galvanizing flue gas, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, The processor executes the computer program to realize the steps of the desulfurization and denitrification control method under the fluctuating working condition of galvanizing flue gas as claimed in any one of claims 1-7.

Images