Control method for automatic bottom argon blowing in molten steel refining

Abstract

The invention relates to a control method for automatic bottom argon blowing in molten steel refining. The method comprises the following steps of (1) English identification calculation of a method for increasing the coal gas recovery amount per ton of steel in converter dry dedusting, (2) automatic bottom argon blowing control over a steel ladle in the converter tapping period, and (3) automatic bottom argon blowing control over a converter in the non-tapping period. According to the technical scheme, according to the conditions of converter dry dedusting equipment and process, the corresponding detection technology and the corresponding control method are utilized, and under the condition that system safety is guaranteed, the converter dry dedusting ton steel gas recovery amount is increased.

Description

Technical Field

[0001] This invention relates to a control method, specifically a control method for automatic bottom blowing argon in steel refining, belonging to the field of automatic bottom blowing argon technology for refining furnaces. Background Technology

[0002] Meishan Steel Plant currently has three refining furnaces, and the argon blowing and stirring flow rate for refining is all manually adjusted. The flow rate regulating valve is opened or closed manually based on the actual stirring intensity of the molten steel. However, the flow rate regulation intensity itself lacks quantifiable indicators and is entirely determined manually, resulting in poor stability and accuracy. Secondly, manual adjustment is time-consuming, affecting efficiency. Thirdly, the actual stirring effect relies on human experience and judgment, leading to unsatisfactory control. Therefore, a new solution is urgently needed to address this technical problem. Summary of the Invention

[0003] This invention addresses the technical problems existing in the prior art by providing a control method for automatic bottom blowing argon in steel refining. This technical solution, based on the conditions of the converter dry dust removal equipment and process, utilizes corresponding detection technologies and control methods to increase the amount of gas recovered per ton of steel in converter dry dust removal while ensuring system safety.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: a control method for automatic bottom blowing argon in steel refining, the method comprising the following steps:

[0005] Step 1: Calculation formula for increasing the amount of gas recovered per ton of steel using dry dust removal in converters, where S represents the area of ​​the ladle opening.

[0006] H: Converter furnace number

[0007] F: Argon flow rate from the bottom of the ladle

[0008] P: Pressure at the bottom-blown argon inlet of the ladle

[0009] PLC: Control System

[0010] XV1: Bottom-blowing valve station shut-off valve

[0011] FV1: Bottom blowing valve station flow regulating valve

[0012] C: Amount of molten iron charged per furnace in the converter

[0013] C1: Average amount of molten iron charged in the previous 10 heats (calculated based on the current heat).

[0014] V: Steel output per heat in the converter

[0015] V1: Maximum steel output V1 in the first 10 heats of the converter (calculated based on the current heat).

[0016] V2: Average steel output V2 of the previous 10 converters (calculated based on the current heat).

[0017] T: Time per heat of steel tapping in the converter

[0018] T1: The average tapping time T1 of the first 10 heats (calculated based on the current heat).

[0019] W: The difference between the average molten iron charge C1 of the first 10 converters and the average steel output V2 of the previous 10 converters.

[0020] The second step is the automatic bottom blowing argon control of the ladle during converter tapping.

[0021] After the ladle car arrives at the converter, the molten steel in the ladle needs to be automatically stirred during the tapping process. Since the amount of molten steel in the ladle dynamically increases from zero level during tapping, to ensure that the molten steel remains in a dynamic stirring process throughout the entire tapping process, while preventing excessive stirring when the molten steel level in the ladle is low, the flow rate of the bottom blower needs to be dynamically adjusted. The control method is as follows:

[0022] The production PLC sends the following signals to the automatic bottom argon blowing PLC: the converter furnace number H, the steel output volume V per furnace of the converter, the steel output time per furnace of the converter, and the ladle mouth area S. After receiving the above signals, the automatic bottom argon blowing PLC calculates the average steel output time T1 of the first 10 furnaces of the converter (calculated based on the current furnace), and calculates the maximum steel output volume V1 of the first 10 furnaces of the converter (calculated based on the current furnace). When the ladle car is under the converter furnace and after the production PLC sends the signal that the converter starts to pour steel to the automatic bottom argon blowing PLC, the automatic bottom argon blowing PLC opens the XV1 of the bottom blowing valve station, and sets the flow rate setting value of the automatic bottom argon blowing to 1 / 3 of the maximum flow rate. In order to improve the response time of the system adjustment, the flow control valve FV1 does not adopt PID regulation. The automatic bottom argon blowing control system directly opens the valve opening of the flow control valve FV1 of the automatic bottom argon blowing to 1 / 3 of the full valve opening. At the same time, it detects the pressure P at the inlet of the bottom argon blowing system, calculates 1 / 3 of the maximum steel output volume V1 of the first 10 furnaces of the converter and the ladle mouth area S, and uses the formula to calculate the theoretical pressure P1 at the inlet of the bottom argon blowing system at 1 / 3 of the maximum steel output volume. If P<P1, the ladle is in a normal stirring state. If P>P1, the ladle is in an abnormal stirring state. The automatic bottom argon blowing control system immediately increases the valve opening of the flow control valve FV1 by 10% at the 1 / 3 opening. When the converter steel output time reaches 2 / 3 of the average steel output time T1 of the first 10 furnaces of the converter (calculated based on the current furnace), the flow rate setting value of the automatic bottom argon blowing is set to 2 / 3 of the maximum flow rate. In order to improve the response time of the system adjustment, the flow control valve FV1 does not adopt PID regulation. The automatic bottom argon blowing control system directly opens the valve opening of the flow control valve FV1 of the automatic bottom argon blowing to 2 / 3 of the full valve opening. At the same time, it detects the pressure P at the inlet of the bottom argon blowing system, calculates 2 / 3 of the maximum steel output volume V1 of the first 10 furnaces of the converter and the ladle mouth area S, and uses the formula to calculate the theoretical pressure P2 at the inlet of the bottom argon blowing system at 2 / 3 of the maximum steel output volume. If P<P2, the ladle is in a normal stirring state. If P>P2, the ladle is in an abnormal stirring state. The automatic bottom argon blowing control system immediately increases the valve opening of the flow control valve FV1 by 10% at the 2 / 3 opening. When the converter steel output time reaches 2 / 3 of the average steel output time T1 of the first 10 furnaces of the converter (calculated based on the current furnace), the flow rate setting value of the automatic bottom argon blowing is set to the maximum flow rate. In order to improve the response time of the system adjustment, the flow control valve FV1 does not adopt PID regulation. The automatic bottom argon blowing control system directly opens the valve opening of the flow control valve FV1 of the automatic bottom argon blowing to 100% of the full valve opening.

[0023] Step 3: Automatic bottom argon blowing control during non-steel output period of the converter

[0024] The automatic bottom argon blowing of the ladle adopts visual recognition technology during the non-steel output period of the converter, and automatically adjusts the automatic bottom argon blowing flow rate through visual recognition technology.

[0025] Compared to existing technologies, this invention has the following advantages: This invention relates to a control method for automatic bottom-blowing argon in a refining furnace. The method involves step-by-step control of the ladle bottom-blowing argon flow rate according to the process. During converter tapping, the automatic bottom-blowing argon flow rate is dynamically adjusted based on the amount of molten steel tapped, the tapping time, and the inlet pressure of the automatic bottom-blowing argon control cabinet. During non-converter tapping periods, the system combines image acquisition and calculation analysis of the actual ladle stirring status with traditional automatic control. Based on the refining furnace's production process, different bottom-blowing argon stirring intensities are set under different metallurgical process conditions. Strong stirring is applied when adding small amounts of scrap steel to achieve uniform composition and temperature. Weak stirring is applied to allow inclusions in the molten steel to float, preventing oxygen and nitrogen absorption and slag entrapment caused by exposed molten steel. The bottom-blowing intensity setpoint is automatically generated based on the bottom-blowing pressure and flow rate, and the molten steel surface state. The valve opening is automatically adjusted according to target requirements. Strong or weak stirring states are required at different metallurgical process stages based on the ladle's permeability. The ladle argon blowing and stirring "one-click mode" allows for one-click adjustment and control of the stirring intensity required for processes such as molten steel heating, wire feeding, and the addition of small scrap steel, automatically adjusting to the required argon blowing intensity range. Different stirring flow rates can be set for adjustment, providing intelligent refining argon blowing functionality. Argon blowing and stirring can be automatically triggered based on process conditions and the addition of small scrap steel. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the control device of the present invention;

[0027] Figure 2 This is a schematic diagram of the control flow of the present invention.

[0028] In the diagram: 1. Camera, 2. Steel ladle, 3. Breathable brick, 4. Image processing and control center, 5. Flow regulating valve, 6. Shut-off valve XV1. Detailed Implementation

[0029] To enhance understanding of the present invention, the embodiments will be described in detail below with reference to the accompanying drawings.

[0030] Example 1: See Figure 1 , Figure 2 A method for controlling automatic bottom blowing argon in steel refining, the method comprising the following steps: Step 1: Calculating the English identifier of the method for increasing the gas recovery per ton of steel in dry dust removal in converters, where S is the area of ​​the ladle opening.

[0031] H: Converter furnace number

[0032] F: Argon flow rate at the bottom of the ladle

[0033] P: Pressure at the bottom-blown argon inlet of the ladle

[0034] PLC: Control System

[0035] XV1: Bottom-blowing valve station shut-off valve

[0036] FV1: Bottom blowing valve station flow regulating valve

[0037] C: Amount of molten iron charged per furnace in the converter

[0038] C1: Average amount of molten iron charged in the previous 10 heats (calculated based on the current heat).

[0039] V: Steel output per heat in the converter

[0040] V1: Maximum steel output V1 in the first 10 heats of the converter (calculated based on the current heat).

[0041] V2: Average steel output V2 of the previous 10 converters (calculated based on the current heat).

[0042] T: Time per heat of steel tapping in the converter

[0043] T1: The average tapping time T1 of the first 10 heats (calculated based on the current heat).

[0044] W: The difference between the average molten iron charge C1 of the first 10 converters and the average steel output V2 of the previous 10 converters.

[0045] The second step is the automatic bottom blowing argon control of the ladle during converter tapping.

[0046] After the ladle car arrives at the converter, the molten steel in the ladle needs to be automatically stirred during the tapping process. Since the amount of molten steel in the ladle dynamically increases from zero level during tapping, to ensure that the molten steel remains in a dynamic stirring process throughout the entire tapping process, while preventing excessive stirring when the molten steel level in the ladle is low, the flow rate of the bottom blower needs to be dynamically adjusted. The control method is as follows:

[0047] The production PLC sends the following signals to the automatic bottom argon blowing PLC: the converter ladle number H, the steel output V per ladle of the converter, the steel output time per ladle of the converter, and the area S of the ladle mouth. After receiving the above signals, the automatic bottom argon blowing PLC calculates the average steel output time T1 of the first 10 ladles of the converter (calculated based on the current ladle, adding up the steel output times of the first 10 ladles and dividing by 10 to obtain the average steel output time), and calculates the maximum steel output V1 of the first 10 ladles of the converter (calculated based on the current ladle, selecting the maximum steel output of one ladle from the steel outputs of the first 10 ladles). When the ladle car is under the converter and after the production PLC sends the signal that the converter starts to pour steel to the automatic bottom argon blowing PLC, the automatic bottom argon blowing PLC opens the XV1 of the bottom blowing valve station, sets the flow rate setting value of the automatic bottom argon blowing to 1 / 3 of the maximum flow rate. To improve the response time of the system regulation, the flow control valve FV1 does not use PID regulation. The automatic bottom argon blowing control system directly opens the valve opening of the flow control valve FV1 of the automatic bottom argon blowing to 1 / 3 of the full valve opening. At the same time, it detects the pressure P at the inlet of the bottom argon blowing system, calculates 1 / 3 of the maximum steel output V1 of the first 10 ladles of the converter and the area S of the ladle mouth, and uses the formula to calculate the theoretical pressure P1 at the inlet of the bottom argon blowing system at 1 / 3 of the maximum steel output. If P < P1, the ladle is in a normal stirring state; if P > P1, the ladle is in an abnormal stirring state, and the automatic bottom argon blowing control system immediately increases the valve opening of the flow control valve FV1 by 10% at the 1 / 3 opening. When the converter steel output time reaches 2 / 3 of the average steel output time T1 of the first 10 ladles of the converter (calculated based on the current ladle), the flow rate setting value of the automatic bottom argon blowing is set to 2 / 3 of the maximum flow rate. To improve the response time of the system regulation, the flow control valve FV1 does not use PID regulation. The automatic bottom argon blowing control system directly opens the valve opening of the flow control valve FV1 of the automatic bottom argon blowing to 2 / 3 of the full valve opening. At the same time, it detects the pressure P at the inlet of the bottom argon blowing system, calculates 2 / 3 of the maximum steel output V1 of the first 10 ladles of the converter and the area S of the ladle mouth, and uses the formula to calculate the theoretical pressure P2 at the inlet of the bottom argon blowing system at 2 / 3 of the maximum steel output. If P < P2, the ladle is in a normal stirring state; if P > P2, the ladle is in an abnormal stirring state, and the automatic bottom argon blowing control system immediately increases the valve opening of the flow control valve FV1 by 10% at the 2 / 3 opening. When the converter steel output time reaches 2 / 3 of the average steel output time T1 of the first 10 ladles of the converter (calculated based on the current ladle), the flow rate setting value of the automatic bottom argon blowing is set to the maximum flow rate. To improve the response time of the system regulation, the flow control valve FV1 does not use PID regulation. The automatic bottom argon blowing control system directly opens the valve opening of the flow control valve FV1 of the automatic bottom argon blowing to 100% of the full valve opening.

[0048] Step 3: Automatic bottom argon blowing control during non-steel-output period of the converter

[0049] The automatic bottom blowing argon system in the ladle uses visual recognition technology during the non-steel tapping period of the converter to automatically adjust the flow rate of the automatic bottom blowing argon.

[0050] Working Principle: The system uses a visual recognition system to identify the molten steel level under different operating conditions, establishing relationships between flow valve opening, flow range, ladle bottom blowing argon intensity, and the exposed molten steel ratio. It stores the standard range of exposed molten steel ratios corresponding to strong or weak argon blowing. Strong blowing is defined as an exposed molten steel ratio greater than 80%, weak blowing as less than 25%, and normal blowing as greater than 25% and less than 80%. Strong and weak blowing modes require a fast response time from the automatic bottom blowing argon system. Therefore, in strong and weak blowing modes, the flow control valve of the automatic bottom blowing argon control system directly controls the opening of the flow control valve; the automatic control system does not use PID control. In normal blowing mode, to ensure system stability and minimal disturbance, the automatic bottom blowing argon control system uses PID control. When the ladle is in a non-converter tapping mode and the automatic bottom blowing argon control PLC receives a signal for adding small scrap steel to the ladle, the automatic bottom blowing argon control system automatically switches to strong blowing mode. The automatic bottom-blowing argon control system immediately switches the flow control valve FV1 from PID control mode to valve opening control mode, and opens the valve opening of FV1 to 100%. When the ladle is in non-converter tapping mode and the automatic bottom-blowing argon control PLC receives the signal that the addition of small scrap steel to the ladle has ended, the automatic bottom-blowing argon control system immediately switches from strong stirring mode to normal stirring mode. The automatic bottom-blowing argon control system immediately switches the flow control valve FV1 from valve opening control mode to PID control mode, and automatically adjusts the setpoint of the flow control valve FV1 according to the set flow calculated by the vision system. When the ladle is in non-converter tapping mode and the automatic bottom-blowing argon control PLC receives the signal that the ladle has left the station, the automatic bottom-blowing argon control system immediately switches from normal stirring mode to weak stirring mode. The automatic bottom-blowing argon control system immediately switches the flow control valve FV1 from PID control mode to valve opening control mode, and opens the valve opening of FV1 to 30%. The control process is as follows: Figure 2 .

[0051] It should be noted that the above embodiments are not intended to limit the scope of protection of the present invention. Equivalent transformations or substitutions made based on the above technical solutions all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for controlling automatic bottom-blowing argon in steel refining, characterized in that, The method includes the following steps: Step 1: Calculation formula for methods to increase the amount of gas recovered per ton of steel using dry dust removal in converters. The second step is the automatic bottom blowing argon control of the ladle during converter tapping. The third step is the automatic bottom-blowing argon control of the converter during non-tapping periods.

2. The automatic bottom-blowing argon control method for steel refining according to claim 1, characterized in that, Step 1: The English formula for calculating the method to increase the amount of gas recovered per ton of steel in dry dust removal in converters is as follows: S: Area of ​​the ladle opening H: Converter furnace number F: Argon flow rate from the bottom of the ladle P: Pressure at the bottom-blown argon inlet of the ladle PLC: Control System XV1: Bottom-blowing valve station shut-off valve FV1: Bottom blowing valve station flow regulating valve C: Amount of molten iron charged per furnace in the converter C1: Average amount of molten iron charged in the previous 10 heats (calculated based on the current heat). V: Steel output per heat in the converter V1: Maximum steel output V1 in the first 10 heats of the converter (calculated based on the current heat). V2: Average steel output V2 of the previous 10 converters (calculated based on the current heat). T: Time per heat of steel tapping in the converter T1: The average tapping time T1 of the first 10 heats (calculated based on the current heat). W: The difference between the average hot metal charge C1 and the average tapping volume V2 of the first 10 converters. W = C1 - V2.

3. The automatic bottom-blowing argon control method for steel refining according to claim 2, characterized in that, The second step, automatic bottom blowing argon control of the ladle during converter tapping, is as follows: Once the ladle car reaches the bottom of the converter, the molten steel in the ladle needs to be automatically stirred during the tapping process. Since the amount of molten steel in the ladle dynamically increases from zero during tapping, to ensure that the molten steel remains in a dynamic stirring process throughout the entire tapping process, while also preventing excessive stirring when the molten steel level in the ladle is low, the flow rate of the bottom blower needs to be dynamically adjusted. The control method is as follows: The production PLC sends the following signals to the automatic bottom-blowing argon PLC: converter heat number H, steel output per heat V, steel output per heat, and ladle opening area S. Upon receiving these signals, the automatic bottom-blowing argon PLC calculates the average steel output time T1 for the previous 10 heats (calculated based on the current heat, by adding the steel output times of the previous 10 heats and dividing by 10). It also calculates the maximum steel output V1 for the previous 10 heats (calculated based on the current heat, by selecting the maximum output from the previous 10 heats). When the ladle car is under the converter, and the production PLC simultaneously sends a converter start-up signal to the automatic bottom-blowing argon PLC, the automatic bottom-blowing argon PLC automatically opens the bottom-blowing valve XV1. The automatic bottom-blowing argon flow rate setpoint is set to 1 / 3 of the maximum flow rate. To improve the system's response time, the flow control valve FV1 does not use PID control. The automatic bottom argon blowing control system directly opens the valve opening of the flow regulating valve FV1 for automatic bottom argon blowing to 1 / 3 of the full valve opening. At the same time, it detects the pressure P at the inlet of the bottom argon blowing system, calculates 1 / 3 of the maximum steel output V1 of the first 10 converter tapping operations and the area S of the ladle mouth, and uses a formula to calculate the theoretical pressure P1 at the inlet of the bottom argon blowing system at 1 / 3 of the maximum steel output. If P < P1, the ladle is in a normal stirring state; if P > P1, the ladle is in an abnormal stirring state. The automatic bottom argon blowing control system immediately increases the valve opening of the flow regulating valve FV1 by 10% at the 1 / 3 opening. When the converter tapping time reaches 2 / 3 of the average tapping time T1 of the first 10 converter tapping operations (calculated based on the current tapping operation), the flow set value of the automatic bottom argon blowing is set to 2 / 3 of the maximum flow. To improve the response time of system regulation, the flow regulating valve FV1 does not use PID regulation. The automatic bottom argon blowing control system directly opens the valve opening of the flow regulating valve FV1 for automatic bottom argon blowing to 2 / 3 of the full valve opening. At the same time, it detects the pressure P at the inlet of the bottom argon blowing system, calculates 2 / 3 of the maximum steel output V1 of the first 10 converter tapping operations and the area S of the ladle mouth, and uses a formula to calculate the theoretical pressure P2 at the inlet of the bottom argon blowing system at 2 / 3 of the maximum steel output. If P < P2, the ladle is in a normal stirring state; if P > P2, the ladle is in an abnormal stirring state. The automatic bottom argon blowing control system immediately increases the valve opening of the flow regulating valve FV1 by 10% at the 2 / 3 opening. When the converter tapping time reaches 2 / 3 of the average tapping time T1 of the first 10 converter tapping operations (calculated based on the current tapping operation), the flow set value of the automatic bottom argon blowing is set to the maximum flow. To improve the response time of system regulation, the flow regulating valve FV1 does not use PID regulation. The automatic bottom argon blowing control system directly opens the valve opening of the flow regulating valve FV1 for automatic bottom argon blowing to 100% of the full valve opening.

4. The automatic bottom-blowing argon control method for steel refining according to claim 3, characterized in that, Step 3: Automatic bottom argon blowing control during non-tapping periods of the converter. For the automatic bottom argon blowing of the ladle during non-tapping periods of the converter, visual recognition technology is used to automatically adjust the flow of automatic bottom argon blowing through visual recognition technology.

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