Refractory material for a blast furnace and method for manufacturing same

Abstract

The utility model discloses a kind of regenerative steel rolling heating furnace blowback process furnace pressure control system, it is related to metallurgical industrial furnace kiln automatic control technical field, and it includes: pattern recognizer, double mode feedforward compensator, PID feedback controller and signal adder;The pattern recognizer is connected with the double mode feedforward compensator;The double mode feedforward compensator, PID feedback controller is connected with the signal adder respectively.The utility model is introduced feedforward control, carries out feedforward compensation, takes action in advance before furnace pressure actual fluctuation, overcomes the hysteresis nature drawback of traditional PID control, to significantly inhibit furnace pressure fluctuation in blowback process, maintains furnace pressure stable.

Description

Technical Field

[0001] This utility model relates to the field of automatic control technology for furnaces and kilns in the metallurgical industry, and more specifically to a furnace pressure control system for the backflushing process of a regenerative steel rolling heating furnace. Background Technology

[0002] Regenerative rolling mill heating furnaces utilize regenerators to recover waste heat from flue gas, achieving high efficiency and energy saving through periodic reversal. During the reversal process, when one side of the gas pipeline switches from "gas supply" to "flue gas exhaust," the gas in the common gas pipeline is rapidly drawn away, resulting in a large amount of CO being released into the flue gas, wasting energy and polluting the environment. To eliminate the CO release defect caused by reversing combustion in regenerative rolling mill heating furnaces, flue gas backflushing technology has been developed to recover and utilize the gas in the common pipeline. However, the backflushing recovery pipeline system is complex. When the backflushing valve switches, the gas intake power changes from the gas pipeline pressure to the backflushing pipeline pressure. There is a lag between the logic timing control and equipment action, causing the furnace pressure to rise or fall sharply in a short period of time, forming a significant pressure funnel or pressure pulsation. This drastic pressure fluctuation leads to a series of problems: 1. Cold air intake: When the furnace pressure is too low, a large amount of cold air will be drawn in from the gaps in the furnace door, inspection hole and other gaps, which will reduce the furnace temperature, increase the oxidation and burning loss of steel billets and cause energy waste.

[0003] 2. High-temperature smoke and flame: When the furnace pressure is too high, high-temperature flue gas and flame will escape, which not only wastes energy, but also burns the furnace equipment, deteriorates the working environment, and poses safety hazards.

[0004] 3. Impact on heating quality: Unstable furnace pressure leads to unstable temperature field and atmosphere inside the furnace, affecting the uniform heating of steel billets and ultimately affecting the quality of rolled steel products.

[0005] The existing backflushing technology for regenerative rolling mills adjusts the speed of the induced draft fan or the opening of the valve based on the backflushing effect, which seriously ignores the fluctuation of furnace pressure. The backflushing action not only fails to compensate for the pressure drop in time, but may even become the next source of pressure fluctuation, causing system oscillation and resulting in poor control.

[0006] Therefore, how to provide a control system that can effectively suppress furnace pressure fluctuations during the backflushing process is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0007] In view of this, the present invention provides a furnace pressure control system for the backflushing process of a regenerative steel rolling furnace. By introducing feedforward control and performing feedforward compensation, it takes action in advance before the actual fluctuation of furnace pressure, overcoming the lag drawback of traditional PID control, thereby significantly suppressing furnace pressure fluctuations during the backflushing process and maintaining furnace pressure stability.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a furnace pressure control system for the backflushing process of a regenerative steel rolling furnace, comprising: a pattern recognizer, a dual-mode feedforward compensator, a PID feedback controller, and a signal adder; The pattern recognizer is connected to the dual-modal feedforward compensator; The dual-mode feedforward compensator and the PID feedback controller are respectively connected to the signal adder.

[0009] Preferably, the signal adder is used to superimpose the output signals of the dual-mode feedforward compensator and the PID feedback controller to generate a total control signal.

[0010] Preferably, the pattern recognizer is used to receive backflush commands and directional valve status signals, and to identify the current operating mode based on the backflush commands and directional valve status signals.

[0011] Preferably, it also includes a pressure sensor group; the pressure sensor group is connected to the PID feedback controller.

[0012] Preferably, the pressure sensor group includes a furnace pressure sensor and a backflush pipe pressure sensor, which respectively detect the furnace pressure signal and the backflush pipe pressure signal.

[0013] Preferably, it further includes: an induced draft fan actuator; the signal adder is connected to the induced draft fan actuator.

[0014] Preferably, the PID feedback controller includes: a main furnace pressure PID controller and a backflushing system pressure PID controller; The main furnace pressure PID controller is used to output a feedback signal based on the furnace pressure signal; The backflush system pressure PID controller is used to output a coordinated control signal based on the backflush pipeline pressure signal.

[0015] Preferably, the dual-mode feedforward compensator is used to receive the backflush signal and output the feedforward control signal.

[0016] As can be seen from the above technical solution, compared with the prior art, this utility model discloses a furnace pressure control system for the backflushing process of a regenerative steel rolling heating furnace. By introducing feedforward control and performing feedforward compensation, it takes action in advance before the actual fluctuation of furnace pressure, overcoming the lag drawback of traditional PID control, thereby significantly suppressing furnace pressure fluctuations during the backflushing process and maintaining furnace pressure stability. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This utility model provides a schematic diagram of the furnace pressure control system for the backflushing process of a regenerative steel rolling heating furnace. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] This utility model discloses a furnace pressure control system for the backflushing process of a regenerative steel rolling furnace, including: a pattern recognizer, a dual-mode feedforward compensator, a PID feedback controller, and a signal adder; The pattern recognizer is connected to the dual-modal feedforward compensator; The dual-mode feedforward compensator and the PID feedback controller are respectively connected to the signal adder.

[0021] Specifically, the signal adder is used to superimpose the output signals of the dual-mode feedforward compensator and the PID feedback controller to generate a total control signal.

[0022] Specifically, the pattern recognizer is used to receive backflush commands and directional valve status signals, and to identify the current operating mode based on the backflush commands and directional valve status signals.

[0023] Specifically, it also includes a pressure sensor group; the pressure sensor group is connected to the PID feedback controller.

[0024] Specifically, the pressure sensor group includes a furnace pressure sensor and a backflush pipe pressure sensor, which respectively detect the furnace pressure signal and the backflush pipe pressure signal.

[0025] Specifically, it also includes: an induced draft fan actuator; the signal adder is connected to the induced draft fan actuator.

[0026] Specifically, the PID feedback controller includes: a main furnace pressure PID controller and a backflushing system pressure PID controller; The main furnace pressure PID controller is used to output a feedback signal based on the furnace pressure signal; The backflush system pressure PID controller is used to output a coordinated control signal based on the backflush pipeline pressure signal.

[0027] Specifically, the dual-mode feedforward compensator is used to receive backflush signals and output feedforward control signals.

[0028] The feedforward compensator is immediately triggered upon receiving the start signal from the backflushing system (denoted as t=0). Based on the furnace pressure dynamic correction coefficient, the compensator adjusts the induced draft fan regulation required to offset the upcoming pressure fluctuation (usually adjusting the backflushing fan speed or adjusting the backflushing fan valve opening), and generates a feedforward control signal.

[0029] The feedforward control signal is superimposed with the output signal of the furnace pressure PID feedback controller, and they work together on the actuator of the backflushing system.

[0030] Feedforward control is responsible for responding quickly and proactively to known, periodic backflip disturbances. It acts immediately before or during a disturbance, aiming to eliminate its main effects.

[0031] Feedback control is responsible for eliminating residual errors that feedforward control cannot fully compensate for, as well as dealing with other unknown, non-periodic disturbances (such as furnace door opening and closing, billet entry and exit, etc.), to ensure that the furnace pressure remains stable near the set value for a long time.

[0032] The setting of the furnace pressure dynamic correction coefficient includes: at the moment of backflushing intervention, the furnace pressure will fluctuate from a stable value. Through historical data analysis, the furnace pressure change in the period after the start of backflushing is simulated as a first-order inertial response process with pure hysteresis. The furnace pressure decrease curve in the future period (e.g., 5-8 seconds) under backflushing disturbance is statistically analyzed, and the furnace pressure dynamic correction coefficient is set based on the results.

[0033] Specifically, the feedforward control signal is used to temporarily adjust the frequency of the back-blowing fan, and its intensity, start time, and duration can be configured according to the specific furnace type.

[0034] Specifically, the intensity and duration of the feedforward control signal are configurable to adapt to heating furnaces of different sizes and models.

[0035] Specifically, the feedforward control signal and the feedback signal are superimposed by a weighted summation, and an output limit is set to prevent impact on the induced draft fan actuator.

[0036] In one specific embodiment of this utility model, Figure 1The control system structure of this utility model is demonstrated. The core of the system includes: a pattern recognizer, a dual-modal feedforward compensator, a main furnace pressure PID controller, a backflushing system pressure PID controller, and a signal adder.

[0037] Backflush commands and reversing valve status signals are sent to the mode recognizer to determine whether the current mode is "normal combustion" or "backflush".

[0038] The dual-modal feedforward compensator outputs a patterned feedforward control signal U_FF based on the identification results.

[0039] The furnace pressure sensor signal is sent to the main furnace pressure PID controller, which outputs feedback signal U_FB1.

[0040] The backflush pressure sensor signal is sent to the backflush system pressure PID controller, which outputs the coordinated control signal U_FB2.

[0041] The three signals U_FF, U_FB1, and U_FB2 are superimposed in the signal adder to form the total control signal U, which is then sent to the induced draft fan actuator.

[0042] Specifically, the control process is as follows: 1. System initialization: Load the preset furnace pressure dynamic correction coefficient and feedforward compensator gain.

[0043] 2. When the reversing system decides to backflush the heat storage on one side, it sends a warning signal to the controller about 0.5 seconds (adjustable) before the backflush valve opens.

[0044] 3. When the feedforward compensator is triggered, it immediately calculates and outputs a feedforward control signal with a duration of 3 seconds (adjustable). The direction of this signal is to cause the reverse blower speed to be adjusted by frequency conversion (e.g., decreasing or increasing the rated speed by 10%-35%).

[0045] 4. At the same time, the PID feedback controller makes fine adjustments based on the real-time furnace pressure measurement.

[0046] 5. After the signals from both are superimposed, they jointly control the opening of the back blower or valve. Due to the feedforward effect, the pressure of the back blower is adjusted in advance to match the pressure of the gas pipeline. When the back blower starts to intake a large amount of gas, the fluctuation of the furnace pressure is effectively buffered.

[0047] This invention, by introducing feedforward control, takes action before actual furnace pressure fluctuations occur, overcoming the lag inherent in traditional PID control. The feedforward-feedback composite control structure can quickly offset major disturbances and accurately eliminate steady-state errors, significantly reducing the amplitude and duration of furnace pressure fluctuations during backflushing. It is easily implemented in existing DCS or PLC control systems, with low modification costs and significant benefits. It effectively reduces billet oxidation loss, saves energy, extends equipment life, and improves the working environment.

[0048] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0049] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A furnace pressure control system for the backflushing process of a regenerative steel rolling furnace, characterized in that, include: Pattern recognizer, bimodal feedforward compensator, PID feedback controller and signal adder; The pattern recognizer is connected to the dual-modal feedforward compensator; The dual-mode feedforward compensator and the PID feedback controller are respectively connected to the signal adder.

2. The furnace pressure control system for the backflushing process of a regenerative steel rolling furnace according to claim 1, characterized in that, The signal adder is used to superimpose the output signals of the dual-mode feedforward compensator and the PID feedback controller to generate a total control signal.

3. The furnace pressure control system for the backflushing process of a regenerative steel rolling furnace according to claim 1, characterized in that, The pattern recognizer is used to receive backflush commands and directional valve status signals, and to identify the current operating mode based on the backflush commands and directional valve status signals.

4. The furnace pressure control system for the backflushing process of a regenerative steel rolling furnace according to claim 1, characterized in that, It also includes a pressure sensor group; the pressure sensor group is connected to the PID feedback controller.

5. The furnace pressure control system for the backflushing process of a regenerative steel rolling furnace according to claim 4, characterized in that, The pressure sensor group includes a furnace pressure sensor and a backflush pipe pressure sensor, which detect the furnace pressure signal and the backflush pipe pressure signal, respectively.

6. The furnace pressure control system for the backflushing process of a regenerative steel rolling furnace according to claim 1, characterized in that, Also includes: Exhaust fan actuator; The signal adder is connected to the induced draft fan actuator.

7. The furnace pressure control system for the backflushing process of a regenerative steel rolling furnace according to claim 5, characterized in that, The PID feedback controllers include: a main furnace pressure PID controller and a backflushing system pressure PID controller; The main furnace pressure PID controller is used to output a feedback signal based on the furnace pressure signal; The backflush system pressure PID controller is used to output a coordinated control signal based on the backflush pipeline pressure signal.

8. The furnace pressure control system for the backflushing process of a regenerative steel rolling furnace according to claim 1, characterized in that, The dual-mode feedforward compensator is used to receive backflush signals and output feedforward control signals.

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