A method for quickly opening oxygen in converter smelting

Abstract

The application relates to a method for quickly opening oxygen in a converter smelting, and relates to the field of oxygen gun oxygen blowing systems. In the oxygen opening time, the valve position of a pressure regulating valve is formula (t0-t1) / t, and the valve position of a flow regulating valve is the application has the beneficial effects that the method can improve the oxygen opening speed of the converter, improve the blowing rate at the oxygen blowing point, reduce the iron content in the steel slag, improve the metal yield, avoid the foaming of the slag in the converter, reduce the oxygen consumption, shorten the converter smelting time, and reduce the number of abnormal lifting of the oxygen lance.

Description

Technical Field

[0001] The invention relates to the field of oxygen lance oxygen blowing systems, and in particular to a method for quickly opening oxygen in converter smelting. Background Art

[0002] As the most crucial piece of equipment in the steelmaking process, the converter's oxygen flow rate control plays a crucial role in the rapidity and accuracy of its performance. This control is crucial for improving the steel endpoint accuracy, reducing oxygen consumption, shortening the converter's smelting cycle, ensuring safe production, and ultimately lowering steelmaking costs. The oxygen blowing process is generally divided into the oxygen-on stage and the normal oxygen-blowing stage. Controlling the oxygen flow rate during the oxygen-on stage is a key challenge in controlling oxygen flow rate throughout the entire smelting process.

[0003] The automatic control equipment of the converter oxygen lance system is generally pressure detection, flow detection, pressure regulating valve, flow regulating valve, two or more shut-off valves, manual shut-off valve and bypass. Due to factors such as unstable oxygen supply pressure of the oxygen production system, simultaneous oxygen blowing of multiple converters, or instantaneous pressure changes when blowing and stopping oxygen, the inlet pressure of the oxygen lance system is not stable. It is difficult to stabilize the oxygen flow when controlling with one regulating valve, so the oxygen lance system is generally a two-stage regulation. The first-level pressure regulation is used to stabilize the inlet pressure of the rear-end flow regulating valve, and the first-level flow regulation is used to regulate and stabilize the oxygen blowing flow. When the converter is smelting, the oxygen lance system receives an oxygen opening signal, at which time the shut-off valve is opened and oxygen is ejected from the oxygen lance. After the shut-off valve is opened, the oxygen lance control can be divided into the oxygen opening control stage and the normal oxygen blowing stage. The oxygen flow fluctuates greatly at the moment of opening the blowing, and this is the oxygen opening stage control. After the oxygen opening stage, the oxygen blowing system automatically switches to the normal oxygen blowing stage. See Figure 4 .

[0004] There are two traditional methods for oxygen addition. One is that when the converter begins blowing oxygen, the shut-off valve opens and the regulating valve begins adjusting from the closed state. The oxygen flow rate is adjusted from 0 m³ / h to the set value through PID control. This adjustment process takes a long time. The other is that the regulating valve starts adjusting from a preset opening, which will cause a large oxygen flow peak. Then, according to the PID control rules, the regulating valve will slowly close, causing a flow trough after the peak until the valve adjusts the flow rate to the preset value. This is prone to overshoot and cannot accurately adjust to different set flow values ​​for different inlet pressures. Both methods are not conducive to rapid oxygen addition, are not conducive to flow stability, or the adjustment process is difficult to control. Summary of the Invention

[0005] The object of the present invention is to provide a method for quickly opening oxygen in converter smelting in response to the shortcomings and defects in the prior art, which can increase the converter oxygen opening speed, increase the oxygen blowing point blowing rate, reduce the iron content in the steel slag, improve the metal recovery rate, avoid foaming of the furnace slag, reduce oxygen consumption, shorten the converter smelting time, and reduce the number of abnormal gun lifting times.

[0006] To achieve the above-mentioned object, the present invention adopts the following technical solution: a method for rapidly opening oxygen in converter smelting, which determines the preset valve positions of the pressure regulating valve and the flow regulating valve, the time required for valve opening, and the valve position corresponding to when the regulating valve reaches the set flow rate. The preset valve positions are intended to open oxygen as quickly as possible and to prevent overshoot of the flow rate when the shut-off valve is opened. The method is characterized by:

[0007] According to experiments, for a given outlet pressure, the initial valve position of the pressure regulating valve is only related to the inlet pressure, and the outlet pressure is proportional to the valve position of the regulating valve. However, since the outlet pressure of the pressure regulating valve is kept at a stable value, the pressure regulating valve has a counter-effect here:

[0008] Therefore, the initial valve position of the pressure regulating valve is: V P0 =100-k P0 P, where: V P0 is the initial valve position of the pressure regulating valve; k P0 is the initial valve position coefficient of the pressure regulating valve; P is the inlet pressure;

[0009] When the outlet pressure of the pressure regulating valve is a constant value, in order to make the flow rate the set value, the set flow rate is proportional to the flow regulating valve:

[0010] Therefore, the initial valve position of the flow control valve is: V f0 =k f0 f, where: V f0 is the initial valve position of the pressure regulating valve; k f0 It is the initial valve position system of the pressure regulating valve;

[0011] According to the actual production data, when the oxygen inlet pressure is stable and the pressure after the pressure regulating valve is fixed, for a given flow rate, the valve position of the pressure regulating valve and the valve position of the flow regulating valve are fixed combination values, and the valve position of the pressure regulating valve and the valve position of the flow regulating valve are basically proportional to the given flow rate, that is:

[0012] The valve position of the pressure regulating valve is: V p =k p f, where: V p is the valve position of the pressure regulating valve; k P is the valve position coefficient of the pressure regulating valve; f is the given flow rate;

[0013] The flow control valve position is: V f =k f f, where: V f is the flow control valve position; k f is the valve position coefficient of the flow control valve;

[0014] According to the oxygen flow setting value, the valve position of the pressure regulating valve and the valve position of the flow regulating valve corresponding to the flow can be calculated;

[0015] Considering that the inlet pressure is not stable, and the higher the pressure, the smaller the valve position required to achieve the set flow rate, it can be seen from actual production data that the outlet pressure of the pressure regulating valve is basically proportional to the valve position of the pressure valve throttle valve; and since the pressure regulating valve in the oxygen control system is set to stabilize the pressure, it is necessary to use the pressure regulating valve position caused by the inlet pressure change as the reaction output of the final pressure regulating valve position, that is, the final pressure regulating valve position is V p =k p f-k1P, where: k1 is the valve position coefficient of the pressure regulating valve caused by the change of inlet pressure;

[0016] During the oxygen opening stage, the valve positions of the pressure regulating valve and the flow regulating valve should increase from the initial value over time until the oxygen opening is completed;

[0017] The time required to open the oxygen can be obtained through experiments, so that the flow rate can reach the set value in the shortest time without overshooting, generally 3-5 seconds;

[0018] During the oxygen opening time, the pressure regulating valve position is Where: t is the oxygen opening time t=(t0,t1), the flow control valve position is

[0019] Furthermore, if the shut-off valve is opened and the pressure regulating valve position and the flow regulating valve position are allowed to reach the pressure regulating valve position and the flow regulating valve position corresponding to the set flow rate within a certain period of time from their respective preset values, oxygen can be turned on quickly and accurately, and after oxygen is turned on, PID control is switched to adjust the oxygen flow rate.

[0020] Furthermore, the experiment is specifically an oxygen opening experiment at different valve positions, and the oxygen opening experiment at different valve positions specifically includes the valve position of the pressure regulating valve, the inlet pressure of the pressure regulating valve, the outlet pressure of the pressure regulating valve, and the valve position of the fixed flow regulating valve.

[0021] Furthermore, the actual production data specifically includes: valve position of the pressure regulating valve, inlet pressure and outlet pressure of the pressure regulating valve, valve position of the flow regulating valve, inlet pressure of the flow regulating valve and oxygen flow.

[0022] After adopting the above technical scheme, the beneficial effects of the present invention are: this method can increase the oxygen opening speed of the converter, increase the oxygen blowing point blowing rate, reduce the iron content in the steel slag, improve the metal recovery rate, avoid the foaming of the furnace slag, reduce oxygen consumption, shorten the converter smelting time, and reduce the number of abnormal gun lifting times. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is a diagram of the oxygen valve opening position of the pressure regulating valve in the present invention.

[0025] Figure 2 This is a diagram of the oxygen valve opening position of the flow control valve in the present invention.

[0026] Figure 3 It is an oxygenation effect diagram of the present invention.

[0027] Figure 4 It is an oxygenation effect diagram of the prior art. DETAILED DESCRIPTION

[0028] The technical solution adopted in this specific embodiment is: if the valve position of the pressure regulating valve and the valve position of the flow regulating valve are allowed to reach the pressure regulating valve position and the valve position of the flow regulating valve corresponding to the set flow rate within a certain period of time from their respective preset values ​​after the shut-off valve is opened, oxygen can be quickly and accurately turned on, and after oxygen is turned on, PID control is switched to adjust the oxygen flow.

[0029] To determine the preset valve positions of the pressure regulating valve and the flow regulating valve, the time required to open the valve, and the corresponding valve position when the regulating valve reaches the set flow rate, since the purpose of the preset valve position is to open oxygen as quickly as possible and to prevent overshoot of the flow rate when the shut-off valve is opened, the following features are featured:

[0030] According to the experiment (oxygen opening experiment at different valve positions, and the oxygen opening experiment at different valve positions specifically includes the valve position of the pressure regulating valve, the inlet pressure of the pressure regulating valve, the outlet pressure of the pressure regulating valve, and the valve position of the fixed flow regulating valve), it can be known that for a given outlet pressure, the initial valve position of the pressure regulating valve is only related to the inlet pressure, and the outlet pressure is proportional to the valve position of the regulating valve. However, since the outlet pressure of the pressure regulating valve is kept at a stable value, the pressure regulating valve has a counter-effect here:

[0031] Therefore, the initial valve position of the pressure regulating valve is: V P0 =100-k P0 P, where: V P0 is the initial valve position of the pressure regulating valve; k P0 is the initial valve position coefficient of the pressure regulating valve; P is the inlet pressure.

[0032] When the outlet pressure of the pressure regulating valve is a constant value, in order to make the flow rate the set value, the set flow rate is proportional to the flow regulating valve:

[0033] Therefore, the initial valve position of the flow control valve is: V f0 =k f0 f, where: V f0 is the initial valve position of the pressure regulating valve; kf0 is the initial valve position system of the pressure regulating valve.

[0034] According to the actual production data (pressure regulating valve position, pressure regulating valve inlet pressure, outlet pressure, flow regulating valve position, flow regulating valve inlet pressure and oxygen flow), it is found that when the oxygen inlet pressure is stable and the pressure after the pressure regulating valve is a fixed value, for a given flow value, the pressure regulating valve position and the flow regulating valve position are fixed combination values, and the pressure regulating valve position and the flow regulating valve position are basically proportional to the given flow, that is:

[0035] The valve position of the pressure regulating valve is: V p =k p f, where: V p is the valve position of the pressure regulating valve; k P is the valve position coefficient of the pressure regulating valve; f is the given flow rate;

[0036] The flow control valve position is: V f =k f f, where: V f is the flow control valve position; k f is the valve position coefficient of the flow control valve;

[0037] According to the oxygen flow setting value, the valve position of the pressure regulating valve and the valve position of the flow regulating valve corresponding to the flow can be calculated;

[0038] Considering that the inlet pressure is not stable, and the higher the pressure, the smaller the valve position required to achieve the set flow rate, it can be seen from actual production data that the outlet pressure of the pressure regulating valve is basically proportional to the valve position of the pressure valve throttle valve; and since the pressure regulating valve in the oxygen control system is set to stabilize the pressure, it is necessary to use the pressure regulating valve position caused by the inlet pressure change as the reaction output of the final pressure regulating valve position, that is, the final pressure regulating valve position is V p =k p f-k1P, where: k1 is the valve position coefficient of the pressure regulating valve caused by the change of inlet pressure;

[0039] During the oxygen opening stage, the valve positions of the pressure regulating valve and the flow regulating valve should increase from the initial value over time (e.g. Figure 1-Figure 3 ) until the oxygen is turned on; t0 to t1 is the oxygen turn-on time. In actual production, it is found that the pressure regulating valve can be appropriately extended for a certain time, which is conducive to the flow stability in the normal blowing stage, such as Figure 1 Middle t1 to t2;

[0040] The time required to open the oxygen can be obtained through experiments, so that the flow rate can reach the set value in the shortest time without overshooting, generally 3-5 seconds;

[0041] During the oxygen opening time, the pressure regulating valve position is Where: t is the oxygen opening time t=(t0,t1), the flow control valve position is

[0042] This oxygen addition method has a good effect in the actual application of converters, such as Figure 4 The figure shows the flow curve before modification. It can be seen that the flow rate has a large peak within 1-3 seconds after the oxygen is turned on. According to the PID control, the flow rate is large and the flow regulating valve is closed. The closing of the flow regulating valve causes the pressure in front of the flow regulating valve to increase. Then the pressure regulating valve is closed and the flow rate reaches a trough. After that, the flow rate is increased again. It takes about 30 seconds for the flow rate to stabilize.

[0043] Figure 3 This is the flow curve after the program is modified. It can be seen from the figure that the time from the start of oxygen opening to the flow stabilization is about 3-6 seconds, and there is basically no overshoot phenomenon, which proves that this oxygen opening method can shorten the oxygen opening time.

[0044] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for rapidly opening oxygen in converter smelting, comprising determining the respective preset valve positions of a pressure regulating valve and a flow regulating valve, the time required to open the valves, and the corresponding valve positions when the regulating valves reach the set flow rates. The preset valve positions are intended to rapidly open oxygen and prevent overshoot of the flow rate when the shut-off valve is opened. The method is characterized by: According to experiments, for a given outlet pressure, the initial valve position of the pressure regulating valve is only related to the inlet pressure, and the outlet pressure is proportional to the valve position of the regulating valve. However, since the outlet pressure of the pressure regulating valve is kept at a stable value, the pressure regulating valve has a counter-effect here: Therefore, the initial valve position of the pressure regulating valve is: V P0 =100-k P0 P, where: V P0 is the initial valve position of the pressure regulating valve; k P0 is the initial valve position coefficient of the pressure regulating valve; P is the inlet pressure; When the outlet pressure of the pressure regulating valve is a constant value, in order to make the flow rate the set value, the set flow rate is proportional to the flow regulating valve: Therefore, the initial valve position of the flow control valve is: V f0 =k f0 f, where: V f0 is the initial valve position of the flow control valve; k f0 is the initial valve position coefficient of the flow control valve; According to the actual production data, when the oxygen inlet pressure is stable and the pressure after the pressure regulating valve is fixed, for a given flow rate, the valve position of the pressure regulating valve and the valve position of the flow regulating valve are fixed combination values, and the valve position of the pressure regulating valve and the valve position of the flow regulating valve are basically proportional to the given flow rate, that is: The valve position of the pressure regulating valve is: V p =k p f, where: V p is the valve position of the pressure regulating valve; k P is the valve position coefficient of the pressure regulating valve; f is the given flow rate; The flow control valve position is: V f =k f f, where: V f is the flow control valve position; k f is the valve position coefficient of the flow control valve; According to the oxygen flow setting value, the valve position of the pressure regulating valve and the valve position of the flow regulating valve corresponding to the flow can be calculated; Considering that the inlet pressure is not stable, and the higher the pressure, the smaller the valve position required to achieve the set flow rate, it can be seen from actual production data that the outlet pressure of the pressure regulating valve is basically proportional to the valve position of the pressure valve throttle. Since the pressure regulating valve in the oxygen control system is set to stabilize the pressure, the valve position of the pressure regulating valve caused by the change in the inlet pressure needs to be used as the reaction output of the final pressure regulating valve position, that is, the final pressure regulating valve position is V p =k p f-k1P, where: k1 is the valve position coefficient of the pressure regulating valve caused by the change of inlet pressure; During the oxygen opening stage, the valve positions of the pressure regulating valve and the flow regulating valve should increase from the initial value over time until the oxygen opening is completed; The time required for oxygen opening should be sufficient to ensure that the flow rate reaches the set value in the shortest time without overshooting; During the oxygen opening time, the pressure regulating valve position is Where: t is the oxygen opening time t=(t0,t1), the flow control valve position is 2. The method for rapidly opening oxygen in converter smelting according to claim 1, characterized in that: If the shut-off valve is opened and the pressure regulating valve position and the flow regulating valve position are allowed to reach the pressure regulating valve position and the flow regulating valve position corresponding to the set flow rate from their respective preset values ​​within a certain period of time, oxygen can be opened quickly and accurately. After oxygen is opened, PID control is switched to adjust the oxygen flow.

3. The method for rapidly opening oxygen in converter smelting according to claim 1, characterized in that: The experiment is specifically an oxygen opening experiment at different valve positions, and the oxygen opening experiment at different valve positions specifically includes the valve position of the pressure regulating valve, the inlet pressure of the pressure regulating valve, the outlet pressure of the pressure regulating valve, and the valve position of the fixed flow regulating valve.

4. The method for rapidly opening oxygen in converter smelting according to claim 1, characterized in that: The actual production data specifically include: valve position of the pressure regulating valve, inlet pressure and outlet pressure of the pressure regulating valve, valve position of the flow regulating valve, inlet pressure of the flow regulating valve and oxygen flow.

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