LF refining furnace steel ladle bottom argon blowing optimization control method and device and storage medium

Abstract

According to the LF refining furnace steel ladle bottom argon blowing optimization control method and device and the storage medium, a Darlin digital controller is designed to replace a traditional PID controller, a signal preprocessing control parameter table of a large pure lag control model is established, and optimization of LF furnace bottom argon blowing flow control is achieved. Compared with an original PID (Proportion Integration Differentiation) control technology, the control method has the advantages that the adjusting process is faster, and the overshoot of the system is smaller after the system enters a steady state; the condition that slag is bonded along the tank belt due to excessive splashing of bottom blowing argon is effectively controlled; the soft blowing small flow control effect is better; and the consumption of argon is effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of iron and steel metallurgy, and in particular to an optimization control method, equipment and storage medium for argon blowing at the bottom of a ladle of an LF refining furnace. Background Art

[0002] LF refining furnace, also known as ladle refining furnace, is an extremely important production process in modern high-quality clean steel production. It has the functions of power-on heating, alloy composition adjustment, slag deoxidation and desulfurization, degassing and inclusion removal, etc. LF refining is carried out in the ladle. Since the heating power, slag and alloy are all input from the top of the ladle, it is easy to cause uneven temperature and composition of the molten steel in the upper and lower parts of the ladle. Therefore, the bottom blowing of argon must be used to stir the molten steel in the ladle, so as to achieve uniform temperature and composition of the molten steel, promote slag reaction, degas and inclusion removal, etc.

[0003] LF refining produces different steel grades, different ladle liquid level heights / bottom blowing argon brick permeability, different refining operation stages and other working conditions, which have different requirements for the flow control of bottom blowing argon: the different blockage degrees of the ladle bottom argon permeable bricks cause the permeability area to change with the furnace and the ladle turnover, and the bottom blowing argon control presents a large time-varying property; LF refining requires different stirring intensities in different process treatment stages, so the argon flow set value needs to be changed frequently, and sometimes the set value is only maintained for a very short time, and the set value varies greatly, from 50NL / min required by the soft blowing process to 600NL / min required by the strong stirring process, all of which put forward higher requirements on the performance indicators of the control system.

[0004] The flow of molten steel caused by bottom blowing argon in the refining furnace ladle has the characteristics of large hysteresis and large inertia. The argon control in the refining process is time-varying and nonlinear. Ordinary PID control methods cannot solve the problems of large pure hysteresis and system overshoot, so it is difficult to achieve the purpose of fast and accurate control of argon flow. Summary of the invention

[0005] The purpose of the present invention is to provide an LF refining furnace ladle bottom argon blowing optimization control method, equipment and storage medium, to overcome the problem that the traditional PID control of the LF furnace bottom argon blowing flow rate has large lag and cannot be quickly and accurately adjusted, and to achieve the optimization of the LF furnace ladle bottom argon blowing flow rate control.

[0006] The present invention specifically adopts the following technical solutions:

[0007] According to a first aspect of the present invention, an embodiment of the present invention provides a method for optimizing and controlling argon blowing at the bottom of a ladle of a LF refining furnace, characterized in that it comprises the following steps:

[0008] Collect and analyze the data of the bottom blowing argon set flow rate and actual flow rate at the production site to determine the control dead zone of the bottom blowing argon equipment range so as to avoid it when designing the controller;

[0009] Design a Dalin digital controller whose transfer function is:

[0010]

[0011] Where Z is a discrete complex frequency domain operator;

[0012] For different process stages of LF treatment, the optimal signal preprocessing control parameters TD, T, and K of the Dalin digital controller are summarized through field analysis experiments, and the signal preprocessing control parameter table of the large pure hysteresis control model is established;

[0013] The corresponding bottom blowing argon flow mode is matched according to the refining process treatment stage, and the bottom blowing argon flow is controlled by the Dalin digital controller according to the signal preprocessing control parameter table.

[0014] On the other hand, an embodiment of the present invention also provides an electronic device, comprising a processor and a memory, wherein the memory stores a program that can be run on the processor, and is characterized in that when the program is executed by the processor, the steps of the above-mentioned LF refining furnace ladle bottom argon blowing optimization control method are implemented.

[0015] On the other hand, an embodiment of the present invention further provides a computer-readable storage medium storing at least one program, characterized in that the at least one program can be executed by at least one processor to implement the steps of the above-mentioned LF refining furnace ladle bottom argon blowing optimization control method.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The method of the present invention realizes the optimization of the bottom blowing argon flow control of the LF furnace by designing a Dalin digital controller to replace the traditional PID controller. Compared with the original PID control technology, the adjustment process is faster, and after entering the steady state, the system overshoot is smaller; the excessive splashing of the bottom blowing argon causes slagging along the tank belt, which effectively controls the bottom blowing argon; the soft blowing small flow control effect is better; and the consumption of argon gas is effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic flow chart of an optimization control method for argon blowing at the bottom of a ladle of a LF refining furnace according to Example 1 of the present invention;

[0019] Figure 2 This is a flow chart of the optimization control program of argon blowing at the bottom of the ladle of the LF refining furnace according to Example 1 of the present invention;

[0020] Figure 3 This is a comparison chart between the Dalin controller of the present invention and the PID control effect. DETAILED DESCRIPTION

[0021] In order to make the technical solution of the present invention more clearly understood, the technical solution of the present invention is further described in detail below according to specific embodiments and in combination with the accompanying drawings. Obviously, the following embodiments are only part of the embodiments of the present invention and do not constitute a limitation on the technical solution of the present invention. For those of ordinary skill in the art, other embodiments can also be obtained according to the embodiments of the present application without paying creative labor.

[0022] It should be noted that the order of steps described in the method embodiments in the following embodiments does not constitute a limitation on the technical solution of the present invention. For ordinary technicians in this field, without paying any creative labor, they can also reasonably adjust the order of certain steps according to the embodiments of the present application.

[0023] Example 1

[0024] This embodiment provides a method for optimizing the control of argon blowing from the bottom of the ladle of a LF refining furnace. Figure 1 As shown, the following steps are included:

[0025] Step 101 : collect and analyze data on the set flow rate and actual flow rate of bottom blowing argon at the production site, and determine the control dead zone of the measuring range of the bottom blowing argon equipment so as to avoid it when designing the controller.

[0026] Specifically, the range of the bottom argon blowing equipment is divided into 100 set points. The area where the opening of the regulating valve does not change after the argon blowing flow is set is the control dead zone. The control dead zone usually appears near the two ends of the range. When actually setting, the output of the controller should be outside the dead zone to prevent the actual argon blowing value from changing after the set value is output.

[0027] Step 102: Design a Dalin digital controller to control the output of the argon blowing regulating valve.

[0028] Specifically, the transfer function of the Dalin digital controller is designed as:

[0029]

[0030] Among them, Z is a discrete complex frequency domain operator. The parameter Z can be converted into a function of time domain control that changes with time T through inverse transformation. By calculating the zero-state response of the initial state, the time domain transfer function is determined, thereby obtaining the time domain transfer function of the bottom blowing argon regulating valve output that changes with time.

[0031] If ringing occurs at the output of the Dalin controller, the SIMULINK simulation method commonly used in the industry is used to find out the factors causing the ringing phenomenon, and the ringing is eliminated by adjusting the corresponding D(Z) poles.

[0032] Step 103: Establish a signal preprocessing control parameter table of a large pure lag control model.

[0033] For different process stages of LF treatment, the optimal signal preprocessing control parameters TD, T, and K of the Dalin digital controller are summarized through on-site analysis experiments. Parameter TD includes pure lag time and capacity transition lag time. The lag time is the delay of the system's response to the input signal. Parameter T is the time required for the interference step to cause the PV (process variable) to change to a stable value of about 2 / 3, which reflects the speed of the system's response to the input signal and can be understood as the sampling period. Parameter K is the amplification factor. The greater the sensitivity, the greater K. The above three parameters are control parameters for signal acquisition preprocessing, and the preprocessed signal is used as the input of the Dalin controller.

[0034] Table 1 Signal preprocessing control parameters of large pure lag control model

[0035] Bottom blowing argon mode TD lag time, s T Sampling time, s K magnification Heating stage 2.5～2.8 0.6 1.7 Feeding stage 2.4～2.7 0.6 1.4 Carbonation stage 1.2～1.8 0.9 1.3 Soft blowing stage 2.8～3.8 0.8 1.4

[0036] Step 104, matching the corresponding bottom blowing argon flow pattern according to the refining process treatment stage, applying the model parameters in Table 1 as the control parameters of the Dalin controller, and controlling the bottom blowing argon flow.

[0037] The present invention designs a Dalin digital controller to replace the original PID control design, and corrects the hysteresis of the actual value feedback of argon blowing, thereby avoiding the problem of large fluctuations in flow rate caused by overshoot of the regulating valve opening due to feedback lag in traditional PID control, and realizing rapid and accurate control of the argon flow rate.

[0038] like Figure 2 Shown is a flow chart of the argon blowing optimization control program for the ladle bottom of the LF refining furnace of this embodiment.

[0039] Example 3

[0040] This embodiment provides an electronic device, including a processor and a memory, wherein the memory stores a program that can be run on the processor, and when the program is executed by the processor, the steps of the above-mentioned LF refining furnace ladle bottom blowing argon optimization control method are implemented.

[0041] The above program can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on the remote computer or server.

[0042] Example 4

[0043] This embodiment provides a computer-readable storage medium storing at least one program, and the at least one program can be executed by at least one processor to implement the steps of the above-mentioned LF refining furnace ladle bottom blowing argon optimization control method.

[0044] The above storage media include: U disk, mobile hard disk, read-only memory, random access memory, disk or optical disk and other media that can store program code and their combination. With the development of science and technology, the meaning of storage media may become more and more extensive and not limited to tangible media.

[0045] A production test was conducted on a LF furnace in a steel plant to obtain a comparison of the bottom blowing argon control effects before and after the application of the method of the present invention. Figure 3 As shown:

[0046] Figure 3 In the figure, for the two bottom blowing argon gas of the same ladle, PID control and the Dalin controller control of the present invention (i.e., the Dalin algorithm control in the figure) are respectively adopted. The bottom blowing flow rate of one channel using PID control showed 3 obvious overshoots, and the process continued to fluctuate for a long time. For the other bottom blowing channel using the Dalin controller, the time for the flow rate to enter the steady state is significantly shortened, and no overshoot will occur when the parameters are properly selected. It can be seen that the method of the present invention has greatly improved the technical problems of serious lag in bottom blowing argon control and repeated oscillations after the system enters the steady state.

[0047] Table 2 below is a comparison of the time for bottom blowing argon to enter steady state before and after the application of the method of the present invention in the experiment (10 random furnaces with different ladle numbers):

[0048] Table 2 Comparison of time for bottom blowing argon regulation to enter steady state

[0049]

[0050] By comparing the data in the above table, it can be seen that the bottom blowing argon control model using the method of the present invention has a significantly shorter bottom blowing argon adjustment speed than the traditional PID algorithm before the transformation, and the overshoot is significantly reduced after the system enters the steady state. It can reduce the consumption of argon gas during use, effectively avoid the splashing of molten steel caused by bottom blowing argon, and reduce the slagging of the tank edge.

[0051] The technical solution of the present invention is simple to implement, does not require hardware investment, can add functions to the original system programmable controller, and has good versatility and broad market application prospects.

[0052] Those skilled in the art can understand that the above-mentioned embodiments are specific embodiments for implementing the present invention. In addition to the above-mentioned embodiments, the present invention may also have other implementation modes; any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.

Claims

1. An LF refining furnace ladle bottom blowing argon optimization control method, characterized in that: The steps include: Collect and analyze the data of the set flow rate and actual flow rate of bottom blowing argon at the production site to determine the control dead zone of the bottom blowing argon equipment range so as to avoid it when designing the controller; Design a Dalin digital controller whose transfer function is: Where Z is a discrete complex frequency domain operator; For different process stages of LF treatment, the optimal signal preprocessing control parameters TD, T, and K of the Dalin digital controller are summarized, and the signal preprocessing control parameter table of the large pure lag control model is established; The corresponding bottom blowing argon flow mode is matched according to the refining process treatment stage, and the output of the argon blowing regulating valve is controlled by the Dalin digital controller according to the signal preprocessing control parameter table to control the bottom blowing argon flow.

2. The LF refining furnace ladle bottom blowing argon optimization control method according to claim 1, characterized in that: Also includes: The discrete complex frequency domain operator Z is converted into a function of time domain control changing with time T through inverse transformation. The time domain transfer function is determined by calculating the zero state response of the initial state, and the time domain transfer function of the bottom blowing argon regulating valve output changing with time is obtained.

3. The LF refining furnace ladle bottom blowing argon optimization control method according to claim 1, characterized in that: The measuring range of the bottom argon blowing equipment is equally divided into 100 set points. The area where the setting opening of the regulating valve does not change after the argon blowing flow rate is set is the control dead zone.

4. The LF refining furnace ladle bottom argon blowing optimization control method according to claim 1, characterized in that: Also includes: When ringing occurs in the output of the Dalin controller, the SIMULINK simulation method is used to find out the factors causing the ringing phenomenon, and the ringing is eliminated by adjusting the corresponding D(Z) poles.

5. The LF refining furnace ladle bottom blowing argon optimization control method according to claim 1, characterized in that: The signal preprocessing control parameter table of the large pure lag control model is shown in the following table: Among them, parameter TD includes pure lag time and capacity transition lag time, parameter T is the time required for the process variable to change to about 2 / 3 of the stable value due to the disturbance step, parameter K is the amplification factor, and the three parameters are control parameters for signal acquisition preprocessing. The preprocessed signal is used as the input of the Dalin controller.

6. An electronic device comprising a processor and a memory, wherein the memory stores a program that can be run on the processor, characterized in that: When the program is executed by the processor, the steps of the LF refining furnace ladle bottom blowing argon optimization control method according to any one of claims 1 to 5 are implemented.

7. A computer-readable storage medium storing at least one program, characterized in that: The at least one program can be executed by at least one processor to implement the steps of the LF refining furnace ladle bottom blowing argon optimization control method as described in any one of claims 1-5.

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