Blast furnace pulverized coal injection real-time injection rate deviation control system and method and application

Abstract

The invention belongs to the technical field of steelmaking equipment, and discloses a blast furnace pulverized coal injection real-time injection rate deviation control system and method and application. Comprising a PLC system, a PID controller, a blowing rate detector and a blowing system, the PLC system is connected with the PID controller, the blowing rate detector and an actuator, and the PLC system comprises a real-time monitoring module, an accumulated deviation calculation module and a feedback parameter selection module. By monitoring the injection rate in real time and dynamically switching feedback parameters (an hour accumulated deviation value and a real-time deviation value), the response time of the system is remarkably shortened, and the overshoot phenomenon caused by hysteresis is effectively reduced. By combining the self-adaptive PID controller, proportion, integral and differential coefficients can be automatically adjusted according to the size of the deviation value, real-time fluctuation is inhibited while accumulative errors are eliminated, oscillation adjustment of the coal flow valve is greatly reduced, and stability and continuity of the injection rate are guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of steelmaking equipment, and in particular relates to a real-time injection rate deviation control system, method and application of blast furnace coal powder injection. Background Art

[0002] For blast furnace pulverized coal injection systems, current technology primarily uses hourly cumulative deviations to control the injection rate through PID control of the coal flow valve. This results in a simple control process and severe overshoot during the regulation process. Specifically, the hourly cumulative injection rate deviation is used as a control variable. The value obtained by adding 0.25 to this control variable and dividing it by 0.005 serves as the PID control feedback value, with the PID control setpoint fixed at 50. Simply put, when the hourly cumulative injection rate deviation is +0.1t, (0.1 + 0.25) / 0.005 = 70. This means that when the hourly cumulative injection rate deviation is +0.1t, the coal flow valve opening needs to be increased to reduce the cumulative deviation. Conversely, the coal flow valve opening needs to be decreased to reduce the cumulative deviation. The goal is to ensure that the coal injection rate within each accumulated natural hour is equal to the set value. However, the current situation based on this control method is that when external interference (such as nitrogen pressure fluctuations) causes the hourly cumulative deviation to increase, the hourly cumulative deviation has a certain hysteresis. For example, when the valve gradually increases to 70% opening, the hourly cumulative injection deviation decreases to 0, and the coal flow valve will maintain its current opening. After a period of negative deviation, the valve control opening will gradually decrease again. During the adjustment process, the coal flow valve will experience a long period of oscillation between increasing and decreasing the opening. The real-time injection rate deviates from the set rate required by the blast furnace foreman by more than 2 tons / hour, and the hourly cumulative injection deviation reaches more than 0.5 tons. This has a negative impact on blast furnace production and is not conducive to the real-time stable injection requirements required by blast furnace production.

[0003] The integral nature of hourly accumulated deviations results in significant lag in system response. For example, when an external disturbance (such as a sudden drop in nitrogen pressure) causes a drop in the instantaneous injection rate, the system must wait until the deviation accumulates to a certain threshold before triggering the adjustment action. During this period, the actual injection rate may have deviated significantly from the set value, and the delay in the adjustment command further exacerbates the overshoot phenomenon. After the coal flow valve opening is adjusted, it is often unable to return to the original position in time due to the lag in reducing the deviation. This causes the valve to oscillate repeatedly between "over-opening" and "over-closing", seriously affecting control stability.

[0004] Existing methods rely solely on hourly cumulative deviations as control variables, ignoring the dynamic fluctuations of the real-time injection rate. For example, Chinese patent publication number CN105368996A, titled "Automatic Control Method for Injection Rate in a Blast Furnace Coal Injection System," uses a control strategy that primarily relies on a combination of segmented adjustment based on historical data and fuzzy PID control. It fails to dynamically incorporate the real-time injection rate deviation into the regulation process as an independent control variable. This results in a delayed response to external disturbances (such as nitrogen pressure fluctuations), significant overshoot, and an inability to effectively suppress real-time deviations.

[0005] Therefore, existing blast furnace pulverized coal injection control technologies, due to issues such as hysteresis, a single control dimension, and rigid parameters, struggle to meet the stringent requirements of blast furnace production for injection rate real-time, stability, and anti-interference capabilities. A new control method is urgently needed that can dynamically integrate the real-time rate with accumulated deviations, adaptively adjust control parameters, and achieve smooth transitions. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a real-time injection rate deviation control system, method and application for blast furnace coal powder injection.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A real-time injection rate deviation control system for blast furnace coal powder injection, comprising a PLC system, a PID controller, an injection rate detector, and an injection system, wherein the PLC system, the PID controller, the injection rate detector, and the actuator are all connected and arranged, and the PLC system comprises a real-time monitoring module, a cumulative deviation calculation module, and a feedback parameter selection module;

[0009] The real-time monitoring module can collect injection rate data and calculate the real-time deviation value. The cumulative deviation calculation module can calculate the hourly cumulative injection deviation and its absolute value. The feedback parameter selection module can select the hourly cumulative deviation or the processed real-time deviation value as the PID input according to the absolute value threshold (0.1t). The PID controller can output the coal flow valve opening adjustment instruction based on the selected feedback parameter. The injection system can adjust the injection according to the output of the PID controller.

[0010] The method for controlling the real-time injection rate deviation of blast furnace pulverized coal injection as described above is characterized in that the steps include:

[0011] (1) Monitor the injection rate in real time and calculate the deviation between the real-time injection rate and the set rate;

[0012] (2) Calculate the hourly cumulative injection deviation and take the absolute value;

[0013] (3) When the absolute value of the hourly cumulative injection deviation is ≥0.1 ton, the hourly cumulative injection deviation is used as a feedback parameter for PID control to adjust the coal flow valve opening;

[0014] (4) When the absolute value of the hourly cumulative injection deviation is less than 0.1 ton, the processed real-time injection rate deviation value is used as the feedback parameter of PID control to adjust the coal flow valve opening.

[0015] Furthermore, in step (1), the weight data of the spray tank is collected every second and stored in an array variable, the difference between adjacent seconds is calculated and stored in a second array variable; the average value of the difference is calculated every 5 seconds as the instantaneous spray rate in the initial spray stage.

[0016] Furthermore, in step (2), the hourly cumulative blowing deviation is calculated as follows:

[0017]

[0018] The feedback parameter of the PID controller calculates the output value, and the formula is:

[0019]

[0020] u(t) is the output value of the PID controller, K P is the proportional gain coefficient, K i is the integral gain coefficient, e(t) is the error value at the current moment, τ is the initial moment, K d is the differential gain coefficient.

[0021] Furthermore, the optimization logic of the parameters of the PID control in step (3) and step (4) is:

[0022] When the absolute value of the cumulative deviation is ≥0.1 ton, increase the proportional coefficient and integral coefficient to quickly eliminate the cumulative error;

[0023] When the absolute value of the accumulated deviation is less than 0.1 ton, the proportional coefficient is reduced and the differential coefficient is increased to suppress the real-time rate fluctuation.

[0024] Furthermore, in step (3) and step (4), when the feedback parameters are switched, a gradual momentum transition strategy is adopted;

[0025] During the transition period T (T = 5 to 20 seconds), the weight of the previous feedback parameter is linearly reduced from 100% to 0%, and the weight of the new feedback parameter is linearly increased from 0% to 100%; the PID output value during the transition period is the weighted sum of the new and old feedback parameters, where the weighted value is set by the staff based on experience.

[0026] Furthermore, the real-time blowing rate deviation value after the processing in step (4) is smoothed by a first-order low-pass filter, and the filtering formula is:

[0027] y n =αx n +(1-α)y n-1

[0028] Where, α = 0.1-0.3, x n is the current real-time deviation value, y n is the output value after filtering.

[0029] Application of any of the above items in real-time injection rate deviation control of pulverized coal injection in a blast furnace.

[0030] The advantages and positive effects achieved by the present invention are:

[0031] 1. This invention significantly shortens system response time and effectively reduces overshoot due to hysteresis by monitoring the injection rate in real time and dynamically switching feedback parameters (hourly cumulative deviation and real-time deviation). Combined with an adaptive PID controller, it automatically adjusts the proportional, integral, and differential coefficients based on the deviation, eliminating cumulative errors while suppressing real-time fluctuations. This significantly reduces oscillation in the coal flow valve's regulation, ensuring the stability and continuity of the injection rate.

[0032] 2. A first-order low-pass filter is introduced to smooth the real-time deviation value (α = 0.1 ~ 0.3), effectively filtering out noise interference and avoiding false operations. When the absolute value of the hourly cumulative deviation is ≥ 0.1 tons, the cumulative error is quickly eliminated by increasing the proportional and integral coefficients; when the deviation is small, the differential effect is enhanced to suppress small fluctuations and achieve precise control. A gradual momentum transition strategy (T = 5 ~ 20 seconds) is adopted. When switching feedback parameters, a smooth transition between the old and new parameters is achieved through linear adjustment of the weights, avoiding step changes in the coal flow valve opening command, and further ensuring the stability of system operation.

[0033] 3. Through a closed-loop control architecture (real-time monitoring → calculation → adaptive adjustment → execution feedback) and dynamic parameter optimization logic, the system reduces the need for manual intervention and enhances its adaptability. It can adapt to complex operating conditions such as nitrogen pressure fluctuations, meeting the stringent requirements of blast furnace production for real-time and stable injection. In practice, the real-time injection rate deviation can be controlled within 2 tons / hour, and the cumulative hourly injection deviation is reduced to less than 0.5 tons, effectively improving the blast furnace's pulverized coal utilization rate, reducing energy consumption, and ensuring the long-term stable and efficient operation of the blast furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a system control flow chart of the present invention;

[0035] Figure 2 The real-time blowing rate deviation processing process and control variable selection logic of the present invention;

[0036] Figure 3 It is a logic diagram of the variables participating in PID control of the present invention;

[0037] Figure 4 This is a historical trend diagram of the injection rate before the implementation of the present invention;

[0038] Figure 5 This is a historical trend diagram of the injection rate after the implementation of the present invention. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below with reference to specific examples. The following examples are merely illustrative and non-restrictive, and should not be used to limit the scope of protection of the present invention.

[0040] The raw materials used in the present invention, unless otherwise specified, are all conventional commercial products. The methods used in the present invention, unless otherwise specified, are all conventional methods in the art. The quality of each substance used in the present invention is the quality of conventional use. The structures, connections, etc. not described in detail in the present invention are understood to be conventional technical means in the art.

[0041] A real-time injection rate deviation control system for blast furnace pulverized coal injection, such as Figure 1 As shown, it includes: a PLC system, a PID controller, a blowing rate detector, and a blowing system. The PLC system and the PID controller, the blowing rate detector, and the actuator are all connected and set. The PLC system includes a real-time monitoring module, a cumulative deviation calculation module, and a feedback parameter selection module;

[0042] The real-time monitoring module can collect injection rate data and calculate the real-time deviation value. The cumulative deviation calculation module can calculate the hourly cumulative injection deviation and its absolute value. The feedback parameter selection module can select the hourly cumulative deviation or the processed real-time deviation value as the PID input according to the absolute value threshold (0.1t). The PID controller can output the coal flow valve opening adjustment instruction based on the selected feedback parameter. The injection system can adjust the injection according to the output of the PID controller.

[0043] For example, the real-time injection rate deviation control method of the above system in blast furnace coal powder injection, such as Figures 2 to 3 As shown, the steps include:

[0044] (1) Monitor the injection rate in real time and calculate the deviation between the real-time injection rate and the set rate;

[0045] (2) Calculate the hourly cumulative injection deviation and take the absolute value;

[0046] (3) When the absolute value of the hourly cumulative injection deviation is ≥0.1 ton, the hourly cumulative injection deviation is used as a feedback parameter for PID control to adjust the coal flow valve opening;

[0047] (4) When the absolute value of the hourly cumulative injection deviation is less than 0.1 ton, the processed real-time injection rate deviation value is used as the feedback parameter of PID control to adjust the coal flow valve opening.

[0048] In this embodiment, in step (1), the weight data of the spray tank is collected every second and stored in an array variable, the difference between adjacent seconds is calculated and stored in a second array variable; the average value of the difference is calculated every 5 seconds as the instantaneous spray rate in the initial spray stage.

[0049] In this embodiment, in step (2), the hourly cumulative blowing deviation is calculated as follows:

[0050]

[0051] In this embodiment, the feedback parameter of the PID controller calculates the output value, and the formula is:

[0052]

[0053] u(t) is the output value of the PID controller, K P is the proportional gain coefficient, K i is the integral gain coefficient, e(t) is the error value at the current moment, τ is the initial moment, K d is the differential gain coefficient.

[0054] In this embodiment, in the parameter steps (3) and (4) of the PID control, the optimization logic includes:

[0055] When the absolute value of the cumulative deviation is ≥0.1 ton, increase the proportional coefficient and integral coefficient to quickly eliminate the cumulative error;

[0056] When the absolute value of the accumulated deviation is less than 0.1 ton, the proportional coefficient is reduced and the differential coefficient is increased to suppress the real-time rate fluctuation.

[0057] In this embodiment, in steps (3) and (4), when the feedback parameters are switched, a gradual momentum transition strategy is adopted, specifically:

[0058] During the transition period T (T = 5 to 20 seconds), the weight of the previous feedback parameter is linearly reduced from 100% to 0%, and the weight of the new feedback parameter is linearly increased from 0% to 100%; the PID output value during the transition period is the weighted sum of the new and old feedback parameters to avoid sudden changes in the opening of the coal flow valve, and the weighted value is set by the staff based on experience.

[0059] In this embodiment, the real-time blowing rate deviation value after the processing in step (4) is smoothed by a first-order low-pass filter, and the filtering formula is:

[0060] y n =αx n +(1-α)y n-1

[0061] Where, α = 0.1-0.3, x n is the current real-time deviation value, y n is the output value after filtering.

[0062] Application of any of the above items in real-time injection rate deviation control of pulverized coal injection in a blast furnace.

[0063] The present invention is specifically:

[0064] like Figure 5 As shown, the PID controller is connected to the PLC system. In the initial stage of blowing, the weight data of the blowing tank is collected every second and stored in an array variable. The difference between adjacent seconds is calculated and stored in a second array variable. The average value of the difference is calculated every 5 seconds as the instantaneous blowing rate in the initial blowing stage. (Set rate - actual injection rate) Δt calculates the hourly cumulative injection deviation; the output value is calculated through the feedback parameter of the PID controller, the formula is: Among them, the initial parameter is K P =1.5, K i =0.05, K d =0.2. The coal flow valve opening is adjusted according to the output value, and closed-loop control is formed through real-time feedback from the position sensor. When the absolute value of the cumulative deviation is ≥0.1 tons, the proportional coefficient and the integral coefficient are increased to quickly eliminate the cumulative error; when the absolute value of the cumulative deviation is <0.1 tons, the proportional coefficient is reduced and the differential coefficient is increased to suppress real-time rate fluctuations. If the feedback parameter is switched, within the transition period T (T = 5 to 20 seconds), the weight of the previous feedback parameter is linearly reduced from 100% to 0%, and the weight of the new feedback parameter is linearly increased from 0% to 100%; during the transition period, the PID output value is the weighted sum of the old and new feedback parameters to avoid sudden changes in the coal flow valve opening. The weighted value is set by the staff based on experience. Subsequently, the processed real-time injection rate deviation value is smoothed using a first-order low-pass filter.

[0065] The present invention significantly shortens system response time and effectively reduces overshoot caused by hysteresis by monitoring the injection rate in real time and dynamically switching feedback parameters (hourly cumulative deviation and real-time deviation value). Combined with an adaptive PID controller, it can automatically adjust the proportional, integral, and differential coefficients according to the deviation value, eliminating the cumulative error while suppressing real-time fluctuations, significantly reducing the oscillation adjustment of the coal flow valve, and ensuring the stability and continuity of the injection rate. A first-order low-pass filter is introduced to smooth the real-time deviation value (α = 0.1 to 0.3), effectively filtering out noise interference and avoiding false operation. When the absolute value of the hourly cumulative deviation is ≥ 0.1 tons, the cumulative error is quickly eliminated by increasing the proportional and integral coefficients; when the deviation is small, the differential effect is enhanced to suppress small fluctuations and achieve precise control. A gradual momentum transition strategy (T = 5 to 20 seconds) is adopted. When switching feedback parameters, a smooth transition between the old and new parameters is achieved through linear weight adjustment, avoiding step changes in the coal flow valve opening command, and further ensuring the stability of system operation. Through a closed-loop control architecture (real-time monitoring → calculation → adaptive adjustment → execution feedback) and dynamic parameter optimization logic, the need for manual intervention is reduced, the system's adaptability is enhanced, and it can adapt to complex operating conditions such as nitrogen pressure fluctuations, meeting the stringent requirements of blast furnace production for real-time and stable injection. In practice, the real-time injection rate deviation can be controlled within 2 tons / hour, and the cumulative hourly injection deviation is reduced to less than 0.5 tons, effectively improving the blast furnace's pulverized coal utilization rate, reducing energy consumption, and ensuring the long-term stable and efficient operation of the blast furnace.

[0066] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A real-time injection rate deviation control system for blast furnace pulverized coal injection, characterized by: It includes a PLC system, a PID controller, a blowing rate detector, and a blowing system. The PLC system, the PID controller, the blowing rate detector, and the actuator are all connected. The PLC system includes a real-time monitoring module, a cumulative deviation calculation module, and a feedback parameter selection module. The real-time monitoring module can collect injection rate data and calculate the real-time deviation value. The cumulative deviation calculation module can calculate the hourly cumulative injection deviation and its absolute value. The feedback parameter selection module can select the hourly cumulative deviation or the processed real-time deviation value as the PID input according to the absolute value threshold. The PID controller can output the coal flow valve opening adjustment instruction based on the selected feedback parameter. The injection system can adjust the injection according to the output of the PID controller.

2. The method for controlling the real-time injection rate deviation of blast furnace coal powder injection according to claim 1, characterized in that: include: (1) Monitor the injection rate in real time and calculate the deviation between the real-time injection rate and the set rate; (2) Calculate the hourly cumulative injection deviation and take the absolute value; (3) When the absolute value of the hourly cumulative injection deviation is ≥0.1 ton, the hourly cumulative injection deviation is used as a feedback parameter for PID control to adjust the coal flow valve opening; (4) When the absolute value of the hourly cumulative injection deviation is less than 0.1 ton, the processed real-time injection rate deviation value is used as the feedback parameter of PID control to adjust the coal flow valve opening.

3. The method according to claim 2, wherein: In the step (1), the weight data of the spray tank is collected every second and stored in an array variable, the difference between adjacent seconds is calculated and stored in a second array variable; the average value of the difference is calculated every 5 seconds as the instantaneous spray rate in the initial spray stage.

4. The method according to claim 2, wherein: In step (2), the calculation method of the hourly cumulative blowing deviation is: In this embodiment, the feedback parameter of the PID controller calculates the output value, and the formula is: u(t) is the output value of the PID controller, K P is the proportional gain coefficient, K i is the integral gain coefficient, e(t) is the error value at the current moment, τ is the initial moment, K d is the differential gain coefficient.

5. The method according to claim 2, wherein: The optimization logic of the parameters of the PID control in step (3) and step (4) is: When the absolute value of the cumulative deviation is ≥0.1 ton, increase the proportional coefficient and integral coefficient to quickly eliminate the cumulative error; When the absolute value of the accumulated deviation is less than 0.1 ton, the proportional coefficient is reduced and the differential coefficient is increased to suppress the real-time rate fluctuation.

6. The method according to claim 2, wherein: In steps (3) and (4), when the feedback parameters are switched, a gradual momentum transition strategy is adopted; During the transition period T, the weight of the previous feedback parameter is linearly reduced from 100% to 0%, and the weight of the new feedback parameter is linearly increased from 0% to 100%; the PID output value during the transition period is the weighted sum of the new and old feedback parameters, where the weighted value is set by the staff based on experience.

7. The method according to claim 2, wherein: The real-time blowing rate deviation value after the processing in step (4) is smoothed by a first-order low-pass filter. The filtering formula is: y n =αx n +(1-α)y n-1 Where, α = 0.1-0.3, x n is the current real-time deviation value, y n is the output value after filtering.

8. Application of any one of claims 1 to 7 in real-time injection rate deviation control of pulverized coal injection in a blast furnace.

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