Blast furnace mechanical stock rod charge level tracking control method and system

Abstract

The invention discloses a blast furnace mechanical stock rod charge level tracking control method and system, and the method comprises the steps: detecting that a stock line exceeds a set depth threshold value in a rod releasing process, switching to a torque control mode, constructing a plurality of linear functions y = Kx + b in a frequency converter to limit the lowering speed of a stock rod, x being the real-time lowering speed of the stock rod, y being the braking torque output by the frequency converter, and b being the braking torque output by the frequency converter; the values of K and b are adjusted in real time according to different blast furnace working conditions, and the braking torque and the speed are in positive correlation; when it is detected that the lowering speed of the stock rod is smaller than a first set speed threshold value and the braking torque is smaller than a set torque threshold value, it is judged that the stock rod reaches the charge level; when the stock rod is put to the material level, it is detected that the lowering speed of the stock rod is increased to a second set speed threshold value, and it is judged that the stock rod is put on the material level; and when the stock rod is judged to step on the material, outputting an additional braking torque. Functional blocks in the frequency converter are used for constructing a multi-segment linear function to achieve torque control, and the method has self-adaptability and alignment rapidness and is not interfered by disturbance torque of a system.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgy, and in particular to a method and system for controlling the material surface tracking of a mechanical sounding rod in a blast furnace. Background Art

[0002] The detection of the material surface in a blast furnace is a link in the iron-making process. The accurate material line of the mechanical sounding rod provides reference data for smelting. Due to the complex environment in the furnace, there is a certain interference to the sounding rod. Therefore, the good anti-interference ability and the diagnosis of its own state of the mechanical sounding rod are crucial. During the process of lowering the rod, a speed closed-loop control is adopted to lower it evenly, and the motor torque mutation is used to capture the material surface, and the following rod torque is dynamically modified according to the material surface depth and the weight of the lowered chain. When phenomena such as material collapse occur and the lowering speed is fast, it switches back to speed control, etc.

[0003] Capturing the material surface and switching to torque control rely on the judgment of the motor torque mutation. However, due to the influence of various resistances or its own faults on the mechanical system, the torque will also change accordingly, resulting in mistakes in capturing the material surface. Secondly, it is difficult to accurately calculate the dynamic setting of the chain weight and torque given. The supporting force of the material surface on the sounding rod weight does not remain constant, and the interference torques such as the gas flow in the furnace are also uncertain. Therefore, its adaptability is not good. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method and system for controlling the material surface tracking of a mechanical sounding rod in a blast furnace.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a method for controlling the material surface tracking of a mechanical sounding rod in a blast furnace, including the following steps:

[0006] Torque control: When it is detected that the material line exceeds the set depth threshold during the process of lowering the rod, switch to the torque control mode. The torque control mode is specifically:

[0007] Construct multiple linear functions y = Kx + b in the frequency converter to limit the lowering speed of the sounding rod, where x is the real-time lowering speed of the sounding rod, y is the braking torque output by the frequency converter, and the values of K and b are adjusted in real time according to different blast furnace working conditions. The braking torque is positively correlated with the speed;

[0008] Following rod judgment: When it is detected that the lowering speed of the sounding rod is less than the first set speed threshold and the braking torque is less than the set torque threshold, it is determined that the sounding rod weight reaches the material surface; when it is detected that the lowering speed of the sounding rod increases to the second set speed threshold after the sounding rod weight reaches the material surface, it is determined that the sounding rod weight steps on the material.

[0009] When it is determined that the sounding rod weight steps on the material, control the frequency converter to output an additional braking torque.

[0010] As a further improvement of the present invention: it further includes:

[0011] Divide multiple speed intervals, and set different linear functions y = Kx + b for each speed interval;

[0012] When it is detected that the lowering speed is in a certain speed interval, the frequency converter outputs the corresponding braking torque according to the linear function corresponding to this speed interval.

[0013] As a further improvement of the present invention: when the lowering speed of the sounding rod is 0, the minimum braking torque is output.

[0014] As a further improvement of the present invention: it further includes:

[0015] Detect the depth of the material line through PLC logic. When the depth of the material line is in the set depth threshold interval, use speed closed-loop control to lower the sounding rod at a constant speed.

[0016] As a further improvement of the present invention: the lowering speed of the sounding rod is controlled within the speed range corresponding to the output frequency of 0 - 10HZ of the frequency converter.

[0017] As a further improvement of the present invention: it further includes: if it is determined that the sounding rod steps on the material, and it is obtained that after the sounding rod reaches the material surface, the speed suddenly changes to x > the second set speed threshold, and the acceleration a > the set value, then trigger the stepping-on-material protection, and the frequency converter outputs an additional braking torque Δy' = α·x' + β·y', where α and β are working condition correction coefficients.

[0018] Based on the same inventive concept, a blast furnace mechanical sounding rod material surface tracking control system is also provided, including:

[0019] The PLC module is used to send a switching instruction to the frequency converter when it detects that the material line exceeds the set depth threshold, so that it switches to the torque control mode;

[0020] The frequency converter is used to construct multiple linear functions y = Kx + b to limit the lowering speed of the sounding rod, where x is the real-time lowering speed of the sounding rod, y is the braking torque output by the frequency converter, and the values of K and b are adjusted in real time according to different blast furnace working conditions. The braking torque is positively correlated with the speed; it is also used to output an additional braking torque when it is determined that the sounding rod steps on the material;

[0021] The speed sensor is used to monitor the speed of the sounding rod in real time and feed back the data to the PLC module and the frequency converter

[0022] The torque sensor is used to monitor the torque of the sounding rod in real time and feed back the data to the PLC module and the frequency converter.

[0023] As a further improvement of the present invention: multiple speed intervals are pre-divided in the frequency converter, each speed interval corresponds to a different linear function, and according to the speed interval corresponding to the lowering speed x of the sounding rod, the corresponding K and b values in the linear function y = Kx + b are called for operation to output the braking torque.

[0024] As a further improvement of the present invention, it further includes:

[0025] A judgment module, configured to determine that the sounding weight reaches the material surface when it detects that the lowering speed of the sounding weight is less than the first set speed threshold and the braking torque is less than the set torque threshold; after the sounding weight reaches the material surface, when it detects that the lowering speed of the sounding weight increases to the second set speed threshold, it determines that the sounding weight steps on the material;

[0026] A processing module, configured to control the frequency converter to output an additional braking torque when it is determined that the sounding weight steps on the material.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] By establishing a linear function relationship y = Kx + b between speed and torque to achieve torque control to limit the lowering speed. Specifically, before reaching the material surface, the speed is basically maintained within the range during speed control, and multiple such linear functions are constructed using the function block of the frequency converter to limit the lowering speed. When the speed is fast, a larger braking torque is output; when the speed is slow, a smaller braking torque is output. The torque corresponding to a speed of 0 is the minimum braking torque. After reaching the material surface, the material stepping judgment and additional torque can prevent the sounding weight from tilting and being buried. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of a method for controlling the material surface tracking of a mechanical sounding weight in a blast furnace according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] To solve the technical problems in the prior art, the present invention will be further described below in conjunction with the drawings and embodiments:

[0032] As Figure 1 shown, an embodiment of the present invention discloses a method for controlling the material surface tracking of a mechanical sounding weight in a blast furnace, including the following steps:

[0033] Torque control: During the process of lowering the sounding weight, when it is detected that the material line exceeds the set depth threshold, it switches to the torque control mode. The torque control mode is specifically:

[0034] Multiple linear functions y = Kx + b are constructed inside the frequency converter to limit the lowering speed of the sounding rod, where x is the real-time lowering speed of the sounding rod, y is the braking torque output by the frequency converter, and the values of K and b are adjusted in real time according to different blast furnace conditions. The braking torque is positively correlated with the speed;

[0035] Sounding rod following judgment: When it is detected that the lowering speed of the sounding rod is less than the first set speed threshold and the braking torque is less than the set torque threshold, it is determined that the sounding rod bob has reached the material surface; when the sounding rod bob reaches the material surface and it is detected that the lowering speed of the sounding rod increases to the second set speed threshold, it is determined that the sounding rod bob has stepped on the material;

[0036] When it is determined that the sounding rod bob has stepped on the material, control the frequency converter to output an additional braking torque.

[0037] The torque control process of the present invention includes the entire material surface tracking stage, and the torque control is mainly realized by the linear function relationship between speed and torque (y = Kx + b, x is the speed, y is the torque). In order to control the speed to basically remain within the range during speed control before reaching the material surface in the torque control process, multiple linear functions are constructed by the frequency converter function block to limit the lowering speed (output a larger braking torque when the speed is fast and a smaller braking torque when the speed is slow). The torque corresponding to a speed of 0 is the minimum torque, and its magnitude needs to be set according to the actual situation during use.

[0038] When x = 0, the minimum braking torque is output, and this torque is only used to maintain the contact between the sounding rod and the material surface to prevent the sounding rod from continuing to sink or separating from the material surface due to gravity.

[0039] Trigger condition: During the lowering process before reaching the material surface, if the speed of the sounding rod drops rapidly due to resistance or interference, the frequency converter outputs a larger braking torque through a multi-segment line function, which may cause the speed to briefly drop to 0.

[0040] Control logic: The frequency converter function block constructs multiple linear functions (such as a segmented linear function group) to limit the speed. For example, when the speed exceeds the upper limit of a certain interval, a larger braking torque is output to force the speed to decrease. If the resistance torque suddenly increases (such as chain jamming, furnace internal gas flow impact), the speed may drop to 0 instantaneously. At this time, the control system will adjust the torque through fuzzy control or an adaptive algorithm to ensure that the speed returns to the preset range.

[0041] For example, after the sounding rod is lowered to the material surface, the speed drops from 0.5 m / s to 0, and the torque stabilizes at 20 N·m (preset minimum torque), and the system enters the sounding rod following judgment mode.

[0042] Further, the values of K and b are adjusted in real time using an adaptive neural network algorithm based on multiple parameters such as the temperature, pressure, and material composition during the real-time operation of the blast furnace. Through learning a large amount of historical data, this algorithm establishes the mapping relationship between each parameter and the values of K and b, thereby achieving precise dynamic adjustment of the values of K and b under different working conditions.

[0043] The follow-up process judgment of the sounding rod is determined by speed and torque. When the speed and torque are less than a certain value, it is considered to reach the burden surface. After reaching the burden surface, if the speed suddenly increases above a certain value, it is considered to step on the charge. At this time, the function set by the frequency converter will give an additional braking torque to prevent the sounding rod weight from tilting and being buried.

[0044] In the present invention, torque control is mainly achieved by the internal function of the frequency converter. The PLC only needs to provide the lowering instruction and the torque switching point. The coordinate points of the multi-segment line can be modified and set in the user parameters and can be modified in real time according to needs.

[0045] Further, in the hardware design, the braking resistor is omitted, and at the same time, the lowering speed is controlled within 10HZ to avoid generating regenerative energy. Specifically, the lowering speed of the sounding rod is controlled within the speed range corresponding to the output frequency of the frequency converter from 0 to 10HZ to ensure the smooth lowering of the sounding rod.

[0046] In some embodiments, the depth of the burden line is detected by PLC logic. When the depth of the burden line is within the set depth threshold range, the sounding rod is lowered at a constant speed using speed closed-loop control.

[0047] That is to say, before switching to torque control in the control method of the present invention, during the lowering of the sounding rod, it is detected by PLC logic. When the burden line is at a certain depth, the lowering process of the sounding rod is speed control, and after reaching a certain depth, it switches to torque control.

[0048] Using PLC logic detection, based on the pre-set depth threshold, when the burden line is in a specific depth range, the lowering process of the sounding rod uses speed control at this time. During the speed control stage, the lowering speed of the sounding rod is collected in real time through a speed sensor, and the speed signal is fed back to the PLC. The PLC adjusts the motor speed using the PID control algorithm according to the deviation between the preset speed value and the feedback speed value to ensure that the sounding rod is lowered at a set speed uniformly. The stable speed lowering provides a good starting condition for accurately judging the arrival at the burden surface and subsequent torque control.

[0049] When the lowering depth reaches the switching depth determined by the depth-switching model constructed based on factors such as the historical operation data of the blast furnace, the characteristics of the materials in the furnace, and the parameters of the furnace type structure, it automatically switches to torque control. During the switching process, the PLC sends a switching instruction to the frequency converter and at the same time transmits relevant parameters such as the current speed and depth to the frequency converter for subsequent torque control operations.

[0050] In some embodiments, the torque control further includes:

[0051] Divide into multiple speed intervals, and set different linear functions y = Kx + b for each speed interval;

[0052] When it is detected that the lowering speed is in a certain speed interval, the frequency converter outputs the corresponding braking torque according to the linear function corresponding to that speed interval.

[0053] Exemplarily, in the torque control stage, the piecewise linear function y = K i x + b i (i is the piecewise serial number), at least 3 speed intervals (such as 0 - 3Hz, 3 - 6Hz, 6 - 10Hz) are divided through the internal function block of the frequency converter, and each interval corresponds to an independent slope K i and intercept b i ; combining the real-time temperature, pressure and material composition data of the blast furnace, the adaptive neural network algorithm is used to dynamically adjust K i and b i , and the braking torque is corrected twice through the fuzzy control algorithm.

[0054] The output frequency of the frequency converter can be used to indirectly represent the lowering wire speed of the sounding rod. The frequency converter is a device that adjusts the motor speed by changing the frequency of the output power supply. In the system of controlling the sounding rod motor through the frequency converter, the output frequency of the frequency converter is basically proportional to the motor speed. According to the corresponding relationship between the motor speed and the lowering wire speed of the sounding rod, the change trend of the lowering wire speed of the sounding rod can be understood through the change of the output frequency of the frequency converter. For example, when the output frequency of the frequency converter increases from 25Hz to 50Hz, the motor speed will increase, and the lowering wire speed of the sounding rod usually also speeds up.

[0055] In some embodiments, in the process of judging the burden surface and the stepped material, when the detection value x of the speed sensor < 0.5m / s and the detection value y of the torque sensor < 50N·m, it is judged that the burden surface is reached; if the speed suddenly changes to x > 1.2m / s after the burden surface is contacted, the stepped material protection is triggered, and the frequency converter outputs an additional braking torque Δy' = f(x', y', θ), where x' is the speed change rate, y' is the torque change rate, and θ is the inclination angle of the sounding rod.

[0056] In some embodiments, when the detection value x of the speed sensor < 0.3m / s and the detection value y of the torque sensor < 40N·m, and the duration t > m seconds, it is judged that the burden surface is reached; if the speed suddenly changes to x > 1.5m / s after the burden surface is contacted, and the acceleration a > 0.8m / s 2 , then the stepped material protection is triggered, and the frequency converter outputs an additional braking torque Δy' = α·x' + β·y', where α and β are working condition correction coefficients, and this additional braking torque is added on the basis of the torque before the speed sudden change.

[0057] y is generated by the inverter driving the motor and transmitted to the sounding rod through a transmission mechanism (such as a gear reducer, chain) to offset the self-weight of the sounding rod and the resistance in the furnace. When x increases, y outputs a larger braking torque according to Kx + b to inhibit excessive speed. When x decreases, y decreases accordingly to avoid the sounding rod jamming due to excessive braking.

[0058] The values of K and b are optimized in real time through an adaptive neural network algorithm. For example:

[0059] When the temperature in the furnace rises and the material expands, the value of K is increased to enhance the braking torque. When the material composition changes and the density decreases, the value of b is decreased to prevent the sounding rod from sinking into the material surface.

[0060] For example, when the sounding rod is lowered at x = 5 m / s, the inverter calculates K = 20, b = 10 according to the current working conditions and outputs a torque y = 20×5 + 10 = 110 N·m. If the pressure in the furnace suddenly increases, the adaptive algorithm adjusts K = 25, b = 15 to prevent the sounding rod from stalling due to increased resistance.

[0061] The embodiment of the present invention also provides a blast furnace mechanical sounding rod material surface tracking control system, including:

[0062] The PLC module is used to send a switching instruction to the inverter to switch it to the torque control mode when it detects that the material line exceeds the set depth threshold;

[0063] The inverter is used to construct multiple linear functions y = Kx + b to limit the lowering speed of the sounding rod, where x is the real-time lowering speed of the sounding rod, y is the braking torque output by the inverter, and the values of K and b are adjusted in real time according to different blast furnace working conditions. The braking torque is positively correlated with the speed; it is also used to output an additional braking torque when it determines that the sounding rod is stepping on the material;

[0064] The speed sensor is used to monitor the speed of the sounding rod in real time and feedback the data to the PLC module and the inverter

[0065] The torque sensor is used to monitor the torque of the sounding rod in real time and feedback the data to the PLC module and the inverter.

[0066] In some embodiments, multiple speed intervals are pre-divided in the inverter, and each speed interval corresponds to a different linear function. According to the speed interval corresponding to the lowering speed x of the sounding rod, the corresponding K and b values in the linear function y = Kx + b are called for operation to output the braking torque.

[0067] In some embodiments, it further includes:

[0068] A judgment module, configured to determine that the probe weight reaches the material surface when it detects that the lowering speed of the probe is less than the first set speed threshold and the braking torque is less than the set torque threshold; after the probe weight reaches the material surface, when it detects that the lowering speed of the probe increases to the second set speed threshold, it determines that the probe weight steps on the material.

[0069] A processing module, configured to control the frequency converter to output an additional braking torque when it is determined that the probe weight steps on the material.

[0070] The main functions of the present invention:

[0071] 1. Utilize the function blocks inside the frequency converter to construct a piecewise linear function to achieve torque control, which has self-adaptability and fast calibration. The material surface capture and follow-up link of the probe are not affected by the system resistance torque and interference torque, and it is more effective and fast to hand over the torque control to the internal calibration of the frequency converter.

[0072] 2. The judgment of stepping on the material and the additional torque after reaching the material surface can prevent the probe weight from tilting and being buried.

[0073] 3. The braking resistor or braking unit is omitted, the hardware of the control cabinet is simplified, and the loss caused by braking failures is reduced.

[0074] In summary, after those of ordinary skill in the art read the documents of the present invention, all other corresponding transformation schemes made without creative mental labor according to the technical solutions and technical concepts of the present invention fall within the scope protected by the present invention.

Claims

1. A method for controlling the material surface tracking of a mechanical sounding rod in a blast furnace, characterized in that, It includes the following steps: Torque control: When it is detected that the material line exceeds the set depth threshold during the process of releasing the ruler, switch to the torque control mode. The torque control mode is specifically as follows: Construct multiple linear functions y = Kx + b in the frequency converter to limit the lowering speed of the sounding rod. Here, x is the real-time lowering speed of the sounding rod, y is the braking torque output by the frequency converter, and the values of K and b are adjusted in real time according to different blast furnace conditions. The braking torque is positively correlated with the speed; Follow the ruler judgment: When it is detected that the lowering speed of the sounding rod is less than the first set speed threshold and the braking torque is less than the set torque threshold, it is determined that the sounding rod bob reaches the material surface; after the sounding rod bob reaches the material surface, when it is detected that the lowering speed of the sounding rod increases to the second set speed threshold, it is determined that the sounding rod bob steps on the material; When it is determined that the sounding rod bob steps on the material, control the frequency converter to output an additional braking torque.

2. The method for controlling the burden surface tracking of the mechanical sounding rod of a blast furnace according to claim 1, characterized in that, It also includes: Divide multiple speed intervals, and set different linear functions y = Kx + b for each speed interval; When it is detected that the lowering speed is in a certain speed interval, the frequency converter outputs the corresponding braking torque according to the linear function corresponding to this speed interval.

3. The material surface tracking control method of a blast furnace mechanical sounding rod according to claim 1, characterized in that, When the lowering speed of the sounding rod is 0, output the minimum braking torque.

4. A method for controlling the burden surface tracking of a mechanical sounding rod in a blast furnace according to claim 1, characterized in that, It also includes: Detect the material line depth through the PLC logic. When the material line depth is in the set depth threshold interval, use speed closed-loop control to lower the sounding rod at a constant speed.

5. A method for controlling the burden surface tracking of a mechanical sounding rod in a blast furnace according to claim 1, characterized in that, The lowering speed of the sounding rod is controlled within the speed range corresponding to the output frequency of 0 - 10HZ of the frequency converter.

6. A method for controlling the material surface tracking of a mechanical sounding rod in a blast furnace according to claim 1, characterized in that, It also includes: If it is determined that the sounding rod bob steps on the material, and it is obtained that after the sounding rod bob reaches the material surface, the speed suddenly changes to x > the second set speed threshold and the acceleration a > the set value, then trigger the stepping-on-material protection, and the frequency converter outputs an additional braking torque Δy' = α·x' + β·y', where α and β are working condition correction coefficients.

7. A mechanical sounding rod material surface tracking control system for a blast furnace, characterized in that, It includes: A PLC module, which is used to send a switching instruction to the frequency converter to switch it to the torque control mode when it is detected that the material line exceeds the set depth threshold; A frequency converter, which is used to construct multiple linear functions y = Kx + b to limit the lowering speed of the sounding rod. Here, x is the real-time lowering speed of the sounding rod, y is the braking torque output by the frequency converter, and the values of K and b are adjusted in real time according to different blast furnace conditions. The braking torque is positively correlated with the speed; it is also used to output an additional braking torque when it is determined that the sounding rod bob steps on the material; A speed sensor, which is used to monitor the speed of the sounding rod in real time and feedback the data to the PLC module and the frequency converter A torque sensor, which is used to monitor the torque of the sounding rod in real time and feedback the data to the PLC module and the frequency converter.

8. A blast furnace mechanical sounding rod burden surface tracking control system according to claim 7, characterized in that, Multiple speed intervals are pre-divided in the frequency converter, and each speed interval corresponds to a different linear function. According to the speed interval corresponding to the lowering speed x of the sounding rod, call the corresponding K and b values in the linear function y = Kx + b to calculate and output the braking torque.

9. A blast furnace mechanical sounding rod burden surface tracking control system according to claim 7, characterized in that, It also includes: A judgment module, which is used to determine that the sounding rod bob reaches the material surface when it is detected that the lowering speed of the sounding rod is less than the first set speed threshold and the braking torque is less than the set torque threshold; after the sounding rod bob reaches the material surface, when it is detected that the lowering speed of the sounding rod increases to the second set speed threshold, it is determined that the sounding rod bob steps on the material; A processing module, which is used to control the frequency converter to output an additional braking torque when it is determined that the sounding rod bob steps on the material.

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