Sinter denitration control method and device, electronic equipment, computer readable medium and program product

Abstract

The application provides a sinter denitration control method and device, electronic equipment, computer readable medium and program product. It belongs to the technical field of sinter control. The sinter denitration control method comprises the following steps: obtaining the current measurement value of the controlled variable and the current set value of the manipulated variable, wherein the controlled variable at least includes the instantaneous nitrogen oxide concentration of the flue gas outlet, the hourly average nitrogen oxide concentration of the flue gas outlet and the outlet pressure of the ammonia water pump, and the manipulated variable at least includes the frequency set value of the ammonia water pump and the opening degree of the ammonia water flow valve; calculating the control increment of the manipulated variable according to the deviation value between the target value and the current measurement value of the controlled variable and the preset coupling weight, wherein the preset coupling weight is used to quantify the influence degree of the controlled variable on the manipulated variable; and updating the current set value of the corresponding manipulated variable according to the control increment to control the execution of sinter denitration. The application improves the stability of sinter denitration control.

Description

Technical Field

[0001] This application belongs to the technical field of sintering control, and specifically relates to a sintering denitrification control method and apparatus, electronic equipment, computer-readable medium and program product. Background Technology

[0002] The sintering process in the steel industry requires the emission of nitrogen oxides, which account for 40%-60% of the total air pollutant emissions from steel enterprises.

[0003] In the sintering denitrification process, the controlled variables include the instantaneous nitrogen oxide concentration at the flue gas outlet, the hourly average nitrogen oxide concentration at the flue gas outlet, and the ammonia pump outlet pressure. Manipulated variables include the ammonia pump frequency setpoint (used to adjust the ammonia dosage, which is negatively correlated with nitrogen oxide concentration) and the ammonia flow valve opening (as an auxiliary adjustment method for ammonia dosage, also negatively correlated with nitrogen oxide concentration). The inventors of this application have found that existing sintering denitrification control technologies still have the following shortcomings: First, the coupling relationship between the controlled and manipulated variables is difficult to handle. Adjusting the ammonia pump frequency setpoint simultaneously affects both the nitrogen oxide concentration and the ammonia pump outlet pressure, while adjusting the ammonia flow valve opening is operationally coupled with the ammonia pump frequency setpoint. Independent or poorly coordinated control of different manipulated variables can easily lead to mutually canceling control effects. Furthermore, the dynamic response characteristics of different controlled variables vary significantly; the instantaneous nitrogen oxide concentration at the flue gas outlet responds quickly, while the hourly average nitrogen oxide concentration at the flue gas outlet responds slowly, further increasing the control difficulty. Traditional single-loop PID control struggles to address these multivariate coupling and time-delay differences.

[0004] Secondly, there is periodic interference in the measurement signal. The nitrogen oxide analyzer requires periodic backflushing during operation, during which the measured value will show an abnormal drop, lasting from several minutes to ten minutes each time. Existing control systems typically cannot identify this type of interference, easily misinterpreting it as actual process fluctuations and executing incorrect control actions.

[0005] The content of the background section is merely the technology known to the inventor and does not necessarily represent the prior art in this field. Summary of the Invention

[0006] This application aims to provide a sintering denitrification control method and apparatus, electronic equipment, computer-readable medium and program product to solve at least one of the above-mentioned technical problems.

[0007] According to one aspect of this application, a sintering denitrification control method is provided, comprising: acquiring the current measured value of a controlled variable and the current set value of a manipulated variable, wherein the controlled variable includes at least the instantaneous nitrogen oxide concentration at the flue gas outlet, the hourly average nitrogen oxide concentration at the flue gas outlet, and the outlet pressure of the ammonia pump, and the manipulated variable includes at least the ammonia pump frequency set value and the ammonia flow valve opening; calculating the control increment of the manipulated variable based on the deviation between the target value and the current measured value of the controlled variable and a preset coupling weight, wherein the preset coupling weight is used to quantify the degree of influence of the controlled variable on the manipulated variable; and updating the current set value of the corresponding manipulated variable according to the control increment to control the execution of sintering denitrification.

[0008] According to some embodiments of this application, the control increment of the manipulated variable is calculated based on the deviation between the target value and the current measured value of the controlled variable and the preset coupling weights, including: calculating the deviation value corresponding to each controlled variable based on the incremental PID algorithm to obtain the corresponding control increment component; and weighting and summing the control increment component corresponding to each controlled variable with the corresponding coupling weights to calculate the control increment of the corresponding manipulated variable.

[0009] According to some embodiments of this application, the sintering denitrification control method further includes: determining whether backflushing interference has occurred based on the decreasing characteristics of the instantaneous nitrogen oxide concentration at the flue gas outlet, wherein the decreasing characteristics include a decreasing magnitude exceeding a preset threshold and a decreasing duration within a preset time range; if so, stopping the updating of all manipulated variables and the updating of the cumulative value of the deviation until the backflushing interference ends.

[0010] According to some embodiments of this application, the sintering denitrification control method further includes: when the hourly average nitrogen oxide concentration at the flue gas outlet exceeds a preset upper limit, reducing the set value of the instantaneous nitrogen oxide concentration at the flue gas outlet according to a preset first correction coefficient and a first correction cycle; when the hourly average nitrogen oxide concentration at the flue gas outlet is lower than a preset lower limit, increasing the set value of the instantaneous nitrogen oxide concentration at the flue gas outlet according to a preset second correction coefficient and a second correction cycle.

[0011] According to some embodiments of this application, the sintering denitrification control method further includes: when the hourly average nitrogen oxide concentration at the flue gas outlet exceeds a preset upper limit or the current hourly nitrogen oxide emission exceeds a preset upper limit of hourly emission, stopping the reduction of the ammonia pump frequency setting and the reduction of the ammonia flow valve opening; when the hourly average nitrogen oxide concentration at the flue gas outlet is lower than a preset lower limit or the current hourly nitrogen oxide emission is lower than a preset lower limit of hourly emission, stopping the increase of the ammonia pump frequency setting and the increase of the ammonia flow valve opening.

[0012] According to some embodiments of this application, the sintering denitrification control method further includes: calculating the nitrogen oxide emission amount for the current hour based on the flue gas flow rate and the hourly average nitrogen oxide concentration at the flue gas outlet; calculating the excess amount when the nitrogen oxide emission amount for the current hour exceeds a preset hourly emission limit, wherein the excess amount is the difference between the actual nitrogen oxide emission amount for the current hour and the hourly emission limit; and adjusting the set value of the hourly average nitrogen oxide concentration at the flue gas outlet for the next hour based on the excess amount and the predicted flue gas flow rate for the next hour.

[0013] According to another aspect of this application, a sintering denitrification control device is also provided, including a data acquisition module, a coupling module, and an execution module. The data acquisition module is used to acquire the current measured value of the controlled variable and the current set value of the manipulated variable. The controlled variable includes at least the instantaneous nitrogen oxide concentration at the flue gas outlet, the hourly average nitrogen oxide concentration at the flue gas outlet, and the outlet pressure of the ammonia pump. The manipulated variable includes at least the ammonia pump frequency set value and the ammonia flow valve opening. The coupling module is used to calculate the control increment of the manipulated variable in each control cycle based on the deviation between the target value and the current measured value of the controlled variable, and a preset coupling weight. The coupling weight is used to quantify the degree of influence of the controlled variable on the manipulated variable. The execution module is used to update the current set value of the corresponding manipulated variable according to the control increment to control the execution of sintering denitrification.

[0014] According to another aspect of this application, an electronic device is also provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the sintering denitrification control method described above.

[0015] According to another aspect of this application, a computer-readable medium having processor-executable non-volatile program code is also provided, the program code causing the processor to perform the sintering denitrification control method described above.

[0016] According to another aspect of this application, a computer program product is also provided, including a computer program stored on a computer-readable medium, the computer program including program instructions that, when executed by a computer, cause the computer to perform the sintering denitrification control method described above.

[0017] The beneficial effects of the technical solutions provided in this application are: This application introduces preset coupling weights to comprehensively calculate the control increment of the corresponding manipulated variable by combining the deviations of the current measured values ​​of multiple controlled variables from their corresponding target values. Compared with the technical shortcomings of traditional single-loop PID control, which can only adjust a single controlled variable and cannot handle the mutual coupling interference between multiple variables, this application quantifies the influence of different controlled variables on the manipulated variable through coupling weights. This achieves coordinated control between multiple controlled variables and multiple manipulated variables, solves the coupling problem between variables such as nitrogen oxide concentration and pump outlet pressure in the denitrification system, and avoids the control effects of different manipulated variables canceling each other out, thereby significantly improving the stability and response speed of the denitrification control system. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0019] Figure 1 A schematic flowchart of a sintering denitrification control method according to an embodiment of this application is shown; Figure 2 A schematic flowchart of step S102 of the sintering denitrification control method according to an embodiment of this application is shown; Figure 3 This paper illustrates another schematic flowchart of the sintering denitrification control method according to an embodiment of this application; Figure 4 A schematic diagram illustrating the control effect of sintering denitrification control in an embodiment of this application is shown. Figure 5 This paper illustrates another schematic flowchart of the sintering denitrification control method according to an embodiment of this application; Figure 6 This paper illustrates another schematic flowchart of the sintering denitrification control method according to an embodiment of this application; Figure 7 This paper illustrates another schematic flowchart of the sintering denitrification control method according to an embodiment of this application; Figure 8 A schematic diagram of the sintering denitrification control device according to an embodiment of this application is shown.

[0020] Explanation of reference numerals in the attached figures: Sintering denitrification control device 1; data acquisition module 11; coupling module 12; execution module 13. Detailed Implementation

[0021] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of interpretation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present application without departing from the scope or spirit thereof. For example, a feature represented or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present application encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0022] The accompanying drawings illustrate one or an example of this application. The detailed description uses numerical and alphabetic designations to refer to features in the drawings. Similar or analogous designations in the drawings and description have been used to refer to similar or analogous parts of this application. As used herein, the terms “first,” “second,” “third,” and “fourth,” etc., are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of a single component.

[0023] The accompanying drawings in the following embodiments clearly and completely describe the technical solutions of this application. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] Figure 1 A schematic flowchart of a sintering denitrification control method according to an embodiment of this application is shown. According to an example embodiment, such as… Figure 1 The sintering denitrification control method includes steps S101-S103. Exemplarily, the sintering denitrification control method of this application can be executed in a computer system such as a set of executable instructions. Exemplarily, the computer system is a sintering denitrification control device. Furthermore, although a logical sequence is shown in the flowchart, under default conditions, the steps shown or described can be executed in a different order than that shown in the flowchart.

[0025] In step S101, the current measured value of the controlled variable and the current set value of the manipulated variable are obtained.

[0026] According to the example embodiment, the controlled variables include at least the instantaneous nitrogen oxide concentration at the flue gas outlet, the hourly average nitrogen oxide concentration at the flue gas outlet, and the ammonia pump outlet pressure, and the manipulated variables include at least the ammonia pump frequency setpoint and the ammonia flow valve opening.

[0027] According to the example embodiment, the denitrification system is a process device used to remove nitrogen oxides from sintering flue gas. The instantaneous nitrogen oxide concentration at the flue gas outlet refers to the concentration of nitrogen oxides in the flue gas at the outlet of the denitrification system at the current moment. The hourly average nitrogen oxide concentration at the flue gas outlet is the average value of the nitrogen oxide concentration at the flue gas outlet over the previous hour. The ammonia pump outlet pressure refers to the pressure value at the outlet of the ammonia delivery pump in the denitrification system. The ammonia pump frequency setpoint is the frequency setpoint of the ammonia delivery pump, used to control the speed of the ammonia delivery pump to adjust the ammonia dosage. The ammonia flow valve opening refers to the degree of opening of the ammonia regulating valve in the denitrification system. The current measured value of the controlled variable refers to the current actual feedback value of the controlled variable obtained in real time by the sintering denitrification control device through the field instruments (such as nitrogen oxide analyzers, pressure transmitters, etc.) of the denitrification system. The current setpoint of the manipulated variable refers to the current command value of the manipulated variable issued by the sintering denitrification control device to the actuators (such as ammonia delivery pumps, ammonia regulating valves) of the denitrification system, used to control the operating state of the actuators.

[0028] For example, the sintering denitrification control device reads the current measured value of the controlled variable from the field instrument of the denitrification system through the industrial communication protocol, and directly reads the current set value of the manipulated variable (such as the ammonia pump frequency set value and the ammonia flow valve opening) from the internal memory of the denitrification system.

[0029] In step S102, the control increment of the manipulated variable is calculated based on the deviation between the target value and the current measured value of the controlled variable, as well as the preset coupling weight.

[0030] According to the example embodiment, the preset coupling weight is used to quantify the influence of the controlled variable on the manipulated variable, with a value range of 0-1. It represents the degree to which the j-th manipulated variable needs adjustment for the deviation value of the i-th controlled variable. The control increment of the manipulated variable refers to the amount of change that the j-th manipulated variable needs to adjust in the current control cycle. In a specific embodiment, there are three types of controlled variables, i, where the value of i can be 1-3. There are two types of manipulated variables, where the value of j can be 1 or 2. i=1 represents the instantaneous nitrogen oxide concentration at the flue gas outlet; i=2 represents the hourly average nitrogen oxide concentration at the flue gas outlet; i=3 represents the ammonia pump outlet pressure. j=1 represents the ammonia pump frequency setpoint; j=2 represents the ammonia flow valve opening.

[0031] For example, the sintering denitrification control device can periodically calculate the control increment of the manipulated variable by setting a control cycle. The control cycle refers to the time interval between two consecutive calculations of the control increment of the manipulated variable by the sintering denitrification control device. For example, in this embodiment, the control cycle can be set to 30s-300s. The control cycle is set by the user according to the process characteristics and is not limited here.

[0032] In one specific embodiment, the control cycle is 60s. At the beginning of each control cycle (e.g., 0s, 60s, 120s...), the sintering denitrification control device acquires the current measured value of the controlled variable in real time, calculates the control increment based on the deviation value and coupling weight, and performs an update of the current set value of the manipulated variable.

[0033] Specifically, at the 0s of the current control cycle (i.e., the start of the current control cycle), the sintering denitrification control device acquires the current measured value of the controlled variable and the current set value of the manipulated variable, calculates the control increment based on the deviation value and coupling weight, and updates the current set value of the manipulated variable; from the 1s to the 59s, the sintering denitrification control device acquires the current measured value of the controlled variable in real time and keeps the current set value of the manipulated variable unchanged (i.e., does not perform control increment calculation); at the 60s of the current control cycle (i.e., the start of the next control cycle), the control increment is calculated and the current set value of the manipulated variable is updated.

[0034] For example, the sintering denitrification control device calculates the deviation value corresponding to each controlled variable based on an incremental PID algorithm to obtain the corresponding control increment component. Then, the control increment component corresponding to each controlled variable is weighted and summed with the corresponding coupling weight to calculate the control increment of the corresponding manipulated variable.

[0035] In step S103, the current set value of the corresponding manipulated variable is updated according to the control increment to control the execution of sintering denitrification.

[0036] According to the example embodiment, the sintering denitrification control device superimposes the control increment calculated in the current control cycle onto the set value of the manipulated variable in the previous control cycle to obtain a new set value of the manipulated variable, and generates and issues the corresponding execution command to the actuator to control the execution of sintering denitrification.

[0037] In one specific embodiment, for the ammonia pump frequency setpoint, the sintering denitrification control device writes the frequency command corresponding to the updated ammonia pump frequency setpoint into the frequency converter of the denitrification system via a communication protocol; for the ammonia flow valve opening, the sintering denitrification control device outputs the opening command corresponding to the updated ammonia flow valve opening to the valve positioner of the denitrification system to adjust the valve opening of the ammonia regulating valve. For example, the ammonia pump frequency setpoint is constrained within the range of 27~37Hz, the ammonia flow valve opening is constrained within the range of 10%~35%, and the single adjustment range does not exceed the preset incremental constraints (e.g., a single adjustment of the pump frequency does not exceed 1Hz, and a single adjustment of the ammonia flow valve opening does not exceed 2%).

[0038] Through the above embodiments, this application introduces preset coupling weights to comprehensively calculate the control increment of the corresponding manipulated variable by combining the deviations of the current measured values ​​of multiple controlled variables from their corresponding target values. Compared with the technical shortcomings of traditional single-loop PID control, which can only adjust a single controlled variable and cannot handle the mutual coupling interference between multiple variables, this application quantifies the degree of influence of different controlled variables on the manipulated variable through coupling weights. This achieves coordinated control between multiple controlled variables and multiple manipulated variables, solves the coupling problem between variables such as nitrogen oxide concentration and pump outlet pressure in the denitrification system, and avoids the control effects of different manipulated variables canceling each other out, thereby significantly improving the stability and response speed of the denitrification control system.

[0039] Figure 2 A schematic flowchart of step S102 of the sintering denitrification control method according to an embodiment of this application is shown. According to an example embodiment, such as... Figure 2 As shown, step S102 includes steps S102a and S102b.

[0040] In step S102a, the deviation value corresponding to each controlled variable is calculated based on the incremental PID algorithm to obtain the corresponding control increment component.

[0041] According to the example embodiment, the calculation formula for the incremental PID algorithm is as follows: ) Formula (1); Where k is the current control cycle; To control the incremental component; Let be the deviation value of the i-th controlled variable in the current control period k; Let be the deviation value of the i-th controlled variable in the (k-1)-th control period; Let be the deviation value of the control variable for the i-th controlled variable in the (k-2)th control period; , and For PID parameters. The sintering denitrification control device calculates the control increment component corresponding to each manipulated variable based on formula (1).

[0042] In step S102b, the control increment component corresponding to each controlled variable is weighted and summed with the corresponding coupling weight to calculate the control increment of the corresponding manipulated variable.

[0043] According to the example embodiment, the formula for calculating the control increment of the manipulated variable is as follows: Formula (2); Where n is the number of controlled variables; For the control increment of the manipulated variable; The coupling weight between the i-th controlled variable and the j-th manipulator is denoted as , and its value ranges from 0 to 1. The sintering denitrification control device calculates the control increment of the manipulator based on formula (2).

[0044] In a specific embodiment, n is 3, representing that there are three types of controlled variables, i.e., the value of i can be 1-3. There are two manipulated variables, i.e., the value of j can be 1 or 2. i=1 represents the controlled variable as the instantaneous nitrogen oxide concentration at the flue gas outlet; i=2 represents the controlled variable as the hourly average nitrogen oxide concentration at the flue gas outlet; i=3 represents the controlled variable as the ammonia pump outlet pressure. j=1 represents the manipulated variable as the ammonia pump frequency setpoint; j=2 represents the manipulated variable as the ammonia flow valve opening. For example, w 11 =0.9 (coupling weight between instantaneous nitrogen oxide concentration at flue gas outlet and ammonia pump frequency setpoint), w 21 =0.5 (coupling weight between hourly average nitrogen oxide concentration at flue gas outlet and ammonia pump frequency setpoint), w 31 =0.6 (coupling weight between ammonia pump outlet pressure and ammonia pump frequency setpoint), w 12 =0.2 (coupling weight between instantaneous nitrogen oxide concentration at flue gas outlet and ammonia flow rate valve opening), w 22 =0.1 (coupling weight between hourly average nitrogen oxide concentration at flue gas outlet and ammonia flow rate valve opening), w 32 =0.1 (coupling weight between ammonia pump outlet pressure and ammonia flow valve opening).

[0045] Through the above embodiments, this application introduces coupling weights to independently calculate the deviation values ​​of multiple controlled variables using an incremental PID algorithm, and then performs a weighted sum with the corresponding coupling weights to generate the control increment of the manipulated variable. Compared to the technical shortcomings of traditional single-loop PID control, which can only adjust a single controlled variable and cannot handle the mutual coupling interference between multiple variables such as the instantaneous nitrogen oxide concentration at the flue gas outlet, the hourly average nitrogen oxide concentration at the flue gas outlet, and the ammonia pump outlet pressure, this application quantifies the influence of each controlled variable on the manipulated variable through independently set coupling weights. This avoids the control effects of different manipulated variables canceling each other out, thereby improving control accuracy and response speed and reducing ammonia consumption while ensuring the stable operation of the denitrification system.

[0046] Figure 3 This illustration shows another schematic flow diagram of the sintering denitrification control method according to an embodiment of this application. According to the example embodiment, as... Figure 3 As shown, the sintering denitrification control method also includes steps S104-S105.

[0047] In step S104, it is determined whether backflushing interference has occurred based on the characteristics of the instantaneous decrease in nitrogen oxide concentration at the flue gas outlet.

[0048] According to the example embodiment, the decrease characteristics include a decrease magnitude exceeding a preset threshold and a decrease duration within a preset time range. Backflushing interference refers to an abnormal decrease in the measured value of the nitrogen oxide analyzer in the denitrification system during backflushing cleaning. For example, the backflushing cycle during backflushing cleaning is 2-4 hours, with multiple backflushing cycles within the cycle, each lasting 5-10 minutes. The preset threshold for the decrease magnitude can be determined as follows: The instantaneous nitrogen oxide concentration at the flue gas outlet is collected during a period of stable operation of the denitrification system without backflushing interference; the standard deviation σ of the instantaneous nitrogen oxide concentration at the flue gas outlet is calculated; and the preset threshold is set to 3σ. For example, when the decrease in the instantaneous nitrogen oxide concentration at the flue gas outlet exceeds 3σ, and the decrease duration is within a preset time range (e.g., 5-10 minutes), backflushing interference is determined to have occurred.

[0049] In step S105, if yes, stop updating all manipulated variables and the cumulative value of the deviation until the backflush interference ends.

[0050] According to the example embodiment, if a backflushing interference is detected, the sintering denitrification control device stops updating all manipulated variables and keeps the ammonia pump frequency setpoint and ammonia flow valve opening unchanged (i.e., stops updating). Simultaneously, the sintering denitrification control device stops updating the accumulated deviation value to prevent abnormal deviation values ​​during backflushing from causing integral saturation. Exemplarily, the sintering denitrification control device pauses updating the accumulated deviation value to prevent error accumulation until the backflushing interference ends, at which point it resumes updating all manipulated variables and the accumulated deviation value.

[0051] Figure 4 A schematic diagram illustrating the control effect of sintering denitrification control according to an embodiment of this application is shown. According to an example embodiment, such as… Figure 4 As shown, the left axis represents nitrogen oxide concentration. The right axis is a shared axis for the ammonia pump frequency setpoint and the ammonia flow valve opening. The horizontal axis is the time axis. The curves show that the frequency of adjustment of the ammonia pump frequency setpoint is much higher than the frequency of adjustment of the ammonia flow valve opening, which conforms to the engineering constraint that valve equipment should not be operated frequently. During the time period marked "abnormal interference (such as backflushing interference)," the nitrogen oxide concentration showed an abnormal decrease, but the ammonia pump frequency setpoint and the ammonia flow valve opening remained unchanged, verifying the effectiveness of backflushing interference identification. Overall, the nitrogen oxide concentration was stably controlled within the target range, and the fluctuation amplitude was significantly reduced.

[0052] Through the above embodiments, this application identifies backflushing interference and distinguishes it from actual process fluctuations, thereby avoiding control malfunctions and improving the robustness and stability of the sintering denitrification process.

[0053] Figure 5 This illustration shows another schematic flow diagram of the sintering denitrification control method according to an embodiment of this application. According to the example embodiment, as... Figure 5 As shown, the sintering denitrification control method also includes steps S106-S107.

[0054] In step S106, when the hourly average nitrogen oxide concentration at the flue gas outlet exceeds the preset upper limit, the set value of the instantaneous nitrogen oxide concentration at the flue gas outlet is reduced according to the preset first correction coefficient and first correction period.

[0055] According to the example embodiment, the preset concentration upper limit refers to the upper limit of the hourly average nitrogen oxide emission control target at the flue gas outlet, with units of mg / m³. 3 The first correction coefficient is a proportional factor used to calculate the reduction range of the instantaneous nitrogen oxide concentration at the flue gas outlet when the hourly average nitrogen oxide concentration at the flue gas outlet exceeds a preset upper limit. The first correction period refers to the time interval between two consecutive instantaneous nitrogen oxide concentration readings at the flue gas outlet when the hourly average nitrogen oxide concentration at the flue gas outlet exceeds the preset upper limit. For example, the first correction coefficient α ranges from 0 to 1, and is set by the user according to the process characteristics of sintering denitrification; it is not limited here. For example, the first correction period can be 10 minutes.

[0056] For example, the formula for calculating the set value of the instantaneous nitrogen oxide concentration at the flue gas outlet after adjustment is as follows: Formula (3); in, This is the set value for the instantaneous nitrogen oxide concentration at the flue gas outlet after adjustment; The set value for the instantaneous nitrogen oxide concentration at the flue gas outlet before adjustment; The average hourly concentration of nitrogen oxides at the flue gas outlet; α is the preset upper or lower limit of the hourly average nitrogen oxide concentration at the flue gas outlet; α is the correction coefficient (first correction coefficient or second correction coefficient). The correction range is expressed in mg / m³. 3 In step S106, The sintering denitrification control device uses formula (3) to reduce the set value of the instantaneous nitrogen oxide concentration at the flue gas outlet, which is the preset upper limit of the hourly average nitrogen oxide concentration at the flue gas outlet. For example, the value of the first correction coefficient can be 0.9.

[0057] In step S107, when the hourly average nitrogen oxide concentration at the flue gas outlet is lower than the preset lower limit, the set value of the instantaneous nitrogen oxide concentration at the flue gas outlet is increased according to the preset second correction coefficient and second correction cycle.

[0058] According to the example embodiment, the preset concentration lower limit refers to the hourly average nitrogen oxide emission control target lower limit, with units of mg / m³. 3 The second correction factor may be the same as or different from the first correction factor, and the correction period is also 10 minutes. For example, the value of the second correction factor may be 0.8.

[0059] For example, in step S107, The preset lower limit of the hourly average nitrogen oxide concentration at the flue gas outlet is used as the lower limit of the concentration. The sintering denitrification control device increases the set value of the instantaneous nitrogen oxide concentration at the flue gas outlet through formula (3).

[0060] Through the above embodiments, this application, by using a target value correction algorithm based on hourly average exceeding the standard, can dynamically adjust the set value of instantaneous nitrogen oxide concentration at the flue gas outlet according to the hourly average nitrogen oxide concentration at the flue gas outlet.

[0061] Figure 6 This illustration shows another schematic flow diagram of the sintering denitrification control method according to an embodiment of this application. According to the example embodiment, as... Figure 6 As shown, the sintering denitrification control method also includes steps S108-S109.

[0062] In step S108, when the hourly average nitrogen oxide concentration at the flue gas outlet exceeds the preset upper limit or the current hourly nitrogen oxide emission exceeds the preset upper limit of hourly emission, the reduction of the ammonia pump frequency setting and the reduction of the ammonia flow valve opening are stopped.

[0063] According to the example embodiment, the sintering denitrification control device monitors the hourly average nitrogen oxide concentration at the flue gas outlet and the current hourly nitrogen oxide emission in real time. When the hourly average nitrogen oxide concentration at the flue gas outlet exceeds a preset upper limit (e.g., 40 mg / m³), the device will trigger a denitrification control. 3 If the current hourly nitrogen oxide emissions exceed the preset hourly emission limit, the sintering denitrification control device will adjust the adjustment mode of the manipulated variables to stop the reduction of the ammonia pump frequency setting and the reduction of the ammonia flow valve opening. For example, the preset hourly emission limit can be set to 4.0 kg / h.

[0064] In step S109, when the hourly average nitrogen oxide concentration at the flue gas outlet is lower than the preset lower limit or the current hourly nitrogen oxide emission is lower than the preset hourly emission lower limit, the increase of the ammonia pump frequency setting and the increase of the ammonia flow valve opening are stopped.

[0065] According to the example embodiment, the sintering denitrification control device monitors the hourly average nitrogen oxide concentration at the flue gas outlet and the current hourly nitrogen oxide emission in real time. When the hourly average nitrogen oxide concentration at the flue gas outlet is lower than a preset lower limit (e.g., 36 mg / m³), the device will control the emission. 3 If the current hourly nitrogen oxide emissions are lower than the preset hourly emission lower limit, the sintering denitrification control device will adjust the adjustment mode of the manipulated variables to stop increasing the ammonia pump frequency setting and the ammonia flow valve opening. For example, the preset hourly emission lower limit can be set to 3.2 kg / h.

[0066] Through the above embodiments, this application monitors the hourly average nitrogen oxide concentration at the flue gas outlet and the current hourly nitrogen oxide emission in real time. When the hourly average nitrogen oxide concentration at the flue gas outlet is lower than the preset lower limit or the current hourly nitrogen oxide emission is lower than the preset lower limit for hourly emissions, the reduction of the ammonia pump frequency setting and the reduction of the ammonia flow valve opening are forcibly stopped. This ensures that the control direction is always in the direction of emission reduction under the risk of exceeding emission standards, and avoids the aggravation of exceeding standards due to reverse adjustment. When the hourly average nitrogen oxide concentration at the flue gas outlet is lower than the preset lower limit or the current hourly nitrogen oxide emission is lower than the preset lower limit for hourly emissions, the increase of the ammonia pump frequency setting and the increase of the ammonia flow valve opening are forcibly stopped, preventing excessive addition and waste of ammonia.

[0067] Figure 7 This illustration shows another schematic flow diagram of the sintering denitrification control method according to an embodiment of this application. According to the example embodiment, as... Figure 7 As shown, the sintering denitrification control method also includes steps S110-S112.

[0068] In step S110, the nitrogen oxide emissions for the current hour are calculated based on the flue gas flow rate and the average hourly nitrogen oxide concentration at the flue gas outlet.

[0069] According to the example embodiment, a sliding hourly window can be used to advance one hour from the current time as the current hour, or the hourly interval in which the current time falls (e.g., 10:00~11:00) can be used as the current hour. For example, the sintering denitrification control device collects the flue gas flow rate and the hourly average nitrogen oxide concentration at the flue gas outlet in real time for the current hour. The formula for calculating the nitrogen oxide emissions for the current hour is as follows: E h =Q h ×C hourly,h Formula (4); Where h represents the current hour; E h Q represents the nitrogen oxide emissions for the current hour; h C represents the flue gas flow rate for the current hour.hourly,h The value represents the hourly average nitrogen oxide concentration at the flue gas outlet for the current hour. The sintering denitrification control device calculates the nitrogen oxide emissions for the current hour according to formula (4).

[0070] In step S111, when the nitrogen oxide emissions in the current hour exceed the preset hourly emission limit, the excess amount is calculated. The excess amount is the difference between the actual nitrogen oxide emissions in the current hour and the hourly emission limit.

[0071] According to the example embodiment, the preset hourly emission limit (denoted by E) limit,h The variable (denoted by ΔE, where ΔE = E) is user-defined and not specified here. Superscalar (denoted by ΔE, where ΔE = E) h -E limit,h A positive value indicates that the nitrogen oxide emissions for the current hour exceed the standard, while a negative value indicates that the nitrogen oxide emissions for the current hour do not exceed the standard and there is room for excess emissions. For example, at the end of the h-hour, the sintering denitrification control device calculates the actual emissions for the h-hour period (i.e., the nitrogen oxide emissions for the current hour) and compares them with the preset upper limit for hourly emissions to calculate the excess amount.

[0072] In step S112, the set value of the hourly average nitrogen oxide concentration at the flue gas outlet for the next hour is adjusted based on the excess amount and the predicted flue gas flow rate for the next hour.

[0073] According to the example embodiment, the next hour is the h+1th hour, and the formula for calculating the set value of the hourly average nitrogen oxide concentration at the flue gas outlet for the next hour is: Formula (5) Among them, C target，h+1 The setpoint for the hourly average nitrogen oxide concentration at the flue gas outlet in the (h+1)th hour; C limit，h+1 Q represents the limit value for nitrogen oxide concentration in the (h+1)th hour; h+1 Let be the flue gas flow rate for the (h+1)th hour. The sintering denitrification control device calculates the set value of the hourly average nitrogen oxide concentration at the flue gas outlet for the next hour (i.e., the (h+1)th hour) according to formula (5), so as to adjust the set value of the hourly average nitrogen oxide concentration at the flue gas outlet for the next hour. For example, when ΔE is positive, the set value of the hourly average nitrogen oxide concentration at the flue gas outlet for the next hour needs to be lowered; when ΔE is negative, the set value of the hourly average nitrogen oxide concentration at the flue gas outlet for the next hour needs to be raised or maintained.

[0074] Through the above embodiments, this application calculates the actual nitrogen oxide emissions for the current hour in real time and compares them with the preset hourly emission limit to obtain the excess amount. Then, based on the excess amount and the predicted flue gas flow rate for the next hour, it dynamically lowers the hourly average nitrogen oxide concentration setting value at the flue gas outlet for the next hour. This rolling optimization method uses the total surplus space of subsequent hours to compensate for the excess emissions of the current hour. Thus, while meeting the environmental protection hourly average concentration limit, it further achieves precise control and rolling balance of total emissions, avoiding the risk of cumulative exceedances that may result from relying solely on concentration control.

[0075] Figure 8 A schematic diagram of a sintering denitrification control device according to an embodiment of this application is shown. According to an example embodiment, such as… Figure 8 As shown, the sintering denitrification control device 1 includes a data acquisition module 11, a coupling module 12, and an execution module 13.

[0076] The data acquisition module 11 is used to acquire the current measured value of the controlled variable and the current set value of the manipulated variable. The controlled variable includes at least the instantaneous nitrogen oxide concentration at the flue gas outlet, the hourly average nitrogen oxide concentration at the flue gas outlet, and the outlet pressure of the ammonia pump. The manipulated variable includes at least the ammonia pump frequency set value and the opening degree of the ammonia flow valve.

[0077] The current measured value of the controlled variable refers to the current actual feedback value of the controlled variable obtained in real time by the data acquisition module 11 through the field instruments (such as nitrogen oxide analyzers, pressure transmitters, etc.) of the denitrification system. The current setpoint value of the manipulated variable refers to the current command value of the manipulated variable issued by the data acquisition module 11 to the actuators (such as ammonia water transfer pumps, ammonia water regulating valves) of the denitrification system, which is used to control the operating status of the actuators.

[0078] For example, the data acquisition module 11 reads the current measured value of the controlled variable from the field instruments of the denitrification system through the industrial communication protocol, and directly reads the current set value of the manipulated variable (such as the ammonia pump frequency set value and the ammonia flow valve opening) from the internal memory of the denitrification system.

[0079] The coupling module 12 is used to calculate the control increment of the manipulated variable in each control cycle based on the deviation between the target value and the current measured value of the controlled variable and the preset coupling weight. The coupling weight is used to quantify the degree of influence of the controlled variable on the manipulated variable.

[0080] For example, the coupling module 12 can periodically calculate the control increment of the manipulated variable by setting a control period. The control period refers to the time interval between two consecutive calculations of the control increment of the manipulated variable by the coupling module 12. For example, in this embodiment, the control period can be set to 30s-300s. The control period is set by the user according to the process characteristics and is not limited here.

[0081] In a specific embodiment, the control cycle is 60s. At the beginning of each control cycle (e.g., the 0th, 60th, 120th, etc.), the coupling module 12 obtains the current measurement value of the controlled variable from the data acquisition module 11 in real time, calculates the control increment based on the deviation value and coupling weight, and performs an update of the current set value of the manipulated variable.

[0082] Specifically, at the 0s of the current control cycle (i.e., the start of the current control cycle), the coupling module 12 obtains the current measured value of the controlled variable and the current setpoint of the manipulated variable from the data acquisition module 11, calculates the control increment based on the deviation value and coupling weight, and updates the current setpoint of the manipulated variable; from the 1s to the 59s, the coupling module 12 obtains the current measured value of the controlled variable in real time through the data acquisition module 11, and keeps the current setpoint of the manipulated variable unchanged (i.e., does not perform control increment calculation); at the 60s of the current control cycle (i.e., the start of the next control cycle), the control increment is calculated and the current setpoint of the manipulated variable is updated.

[0083] For example, the coupling module 12 calculates the deviation value corresponding to each controlled variable based on the incremental PID algorithm to obtain the corresponding control increment component. Then, it calculates the control increment of the corresponding manipulated variable by weighting and summing the control increment component corresponding to each controlled variable with the corresponding coupling weight.

[0084] The execution module 13 is used to update the current set value of the corresponding manipulated variable according to the control increment in order to control the execution of sintering denitrification.

[0085] According to the example embodiment, the execution module 13 superimposes the control increment calculated in the current control cycle onto the set value of the manipulated variable in the previous control cycle to obtain a new set value of the manipulated variable, and generates and issues the corresponding execution command to the execution mechanism to control the execution of sintering denitrification.

[0086] In one specific embodiment, for the ammonia pump frequency setting value, the execution module 13 writes the frequency command corresponding to the updated ammonia pump frequency setting value into the frequency converter of the denitrification system via a communication protocol; for the ammonia flow valve opening degree, the execution module 13 outputs the opening degree command corresponding to the updated ammonia flow valve opening degree to the valve positioner of the denitrification system to adjust the valve opening degree of the ammonia regulating valve. For example, the ammonia pump frequency setting value is constrained within the range of 27~37Hz, the ammonia flow valve opening degree is constrained within the range of 10%~35%, and the single adjustment range does not exceed the preset incremental constraints (e.g., a single adjustment of the pump frequency does not exceed 1Hz, and a single adjustment of the ammonia flow valve opening degree does not exceed 2%).

[0087] Through the above embodiments, this application introduces preset coupling weights to comprehensively calculate the control increment of the corresponding manipulated variable by combining the deviations of the current measured values ​​of multiple controlled variables from their corresponding target values. Compared with the technical shortcomings of traditional single-loop PID control, which can only adjust a single controlled variable and cannot handle the mutual coupling interference between multiple variables, this application quantifies the degree of influence of different controlled variables on the manipulated variable through coupling weights. This achieves coordinated control between multiple controlled variables and multiple manipulated variables, solves the coupling problem between variables such as nitrogen oxide concentration and pump outlet pressure in the denitrification system, and avoids the control effects of different manipulated variables canceling each other out, thereby significantly improving the stability and response speed of the denitrification control system.

[0088] According to another aspect of this application, an electronic device is also provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the sintering denitrification control method described above.

[0089] According to another aspect of this application, a computer-readable medium having processor-executable non-volatile program code is also provided, the program code causing the processor to perform the sintering denitrification control method described above.

[0090] According to another aspect of this application, a computer program product is also provided, including a computer program stored on a computer-readable medium, the computer program including program instructions that, when executed by a computer, cause the computer to perform the sintering denitrification control method described above.

[0091] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or its equivalents are included in this invention.

Claims

1. A method for controlling denitrification during sintering, characterized in that, include: Obtain the current measured value of the controlled variable and the current set value of the manipulated variable, wherein the controlled variable includes at least the instantaneous nitrogen oxide concentration at the flue gas outlet, the hourly average nitrogen oxide concentration at the flue gas outlet, and the ammonia pump outlet pressure, and the manipulated variable includes at least the ammonia pump frequency set value and the ammonia flow valve opening. The control increment of the manipulated variable is calculated based on the deviation between the target value of the controlled variable and the current measured value, and a preset coupling weight, wherein the preset coupling weight is used to quantify the degree of influence of the controlled variable on the manipulated variable; The current set value of the corresponding manipulation variable is updated according to the control increment to control the execution of sintering denitrification.

2. The sintering denitrification control method according to claim 1, characterized in that, The step of calculating the control increment of the manipulated variable based on the deviation between the target value and the current measured value of the controlled variable, and the preset coupling weight, includes: The incremental PID algorithm is used to calculate the deviation value of each controlled variable to obtain the corresponding control increment component. The control increment of the corresponding manipulated variable is calculated by weighting and summing the control increment component corresponding to each controlled variable with the corresponding coupling weight.

3. The sintering denitrification control method according to claim 1, characterized in that, Also includes: Based on the characteristics of the instantaneous nitrogen oxide concentration at the flue gas outlet, it is determined whether backflushing interference has occurred, wherein the characteristics of the decrease include a decrease exceeding a preset threshold and a decrease duration within a preset time range; If so, stop updating all manipulated variables and the cumulative value of the deviation until the backflush interference ends.

4. The sintering denitrification control method according to claim 1, characterized in that, Also includes: When the hourly average nitrogen oxide concentration at the flue gas outlet exceeds the preset upper limit, the set value of the instantaneous nitrogen oxide concentration at the flue gas outlet is reduced according to the preset first correction coefficient and first correction period. When the hourly average nitrogen oxide concentration at the flue gas outlet is lower than the preset lower limit, the set value of the instantaneous nitrogen oxide concentration at the flue gas outlet is increased according to the preset second correction coefficient and second correction period.

5. The sintering denitrification control method according to claim 1, characterized in that, Also includes: When the hourly average nitrogen oxide concentration at the flue gas outlet exceeds the preset upper limit or the current hourly nitrogen oxide emission exceeds the preset upper limit of hourly emission, the reduction of the ammonia pump frequency setting and the reduction of the ammonia flow valve opening are stopped. When the hourly average nitrogen oxide concentration at the flue gas outlet is lower than the preset lower limit or the current hourly nitrogen oxide emission is lower than the preset hourly emission lower limit, the increase of the ammonia pump frequency setting and the increase of the ammonia flow valve opening are stopped.

6. The sintering denitrification control method according to claim 1, characterized in that, Also includes: Calculate the nitrogen oxide emissions for the current hour based on the current hourly flue gas flow rate and the hourly average nitrogen oxide concentration at the flue gas outlet; When the nitrogen oxide emissions for the current hour exceed the preset hourly emission limit, the excess amount is calculated, which is the difference between the actual nitrogen oxide emissions for the current hour and the hourly emission limit. Based on the excess amount and the predicted flue gas flow rate for the next hour, adjust the set value of the hourly average nitrogen oxide concentration at the flue gas outlet for the next hour.

7. A sintering denitrification control device, characterized in that, include: The data acquisition module is used to acquire the current measured value of the controlled variable and the current set value of the manipulated variable. The controlled variable includes at least the instantaneous nitrogen oxide concentration at the flue gas outlet, the hourly average nitrogen oxide concentration at the flue gas outlet, and the outlet pressure of the ammonia pump. The manipulated variable includes at least the ammonia pump frequency set value and the ammonia flow valve opening. The coupling module is used to calculate the control increment of the manipulated variable based on the deviation between the target value of the controlled variable and the current measured value, and a preset coupling weight, wherein the coupling weight is used to quantify the degree of influence of the controlled variable on the manipulated variable; The execution module is used to update the current set value of the corresponding manipulation variable according to the control increment, so as to control the execution of sintering denitrification.

8. An electronic device, characterized in that, The method includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the sintering denitrification control method according to any one of claims 1-6.

9. A computer-readable medium having processor-executable non-volatile program code, characterized in that, The program code causes the processor to execute the sintering denitrification control method according to any one of claims 1-6.

10. A computer program product, characterized in that, Includes a computer program stored on a computer-readable medium, the computer program comprising program instructions that, when executed by a computer, cause the computer to perform the actions as claimed.

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