Dynamic control method for oxygen lance of converter

Abstract

The invention belongs to the technical field of steel smelting, and particularly relates to a converter oxygen lance dynamic control method. Comprising the following steps: S1, acquiring molten steel component data {Ci (t)}, molten steel temperature data T (t) and sound energy signal data E300 (t) in real time; s2, the temperature change rate # imgabs0 # S3 is calculated according to T (t), the dynamic oxygen demand # imgabs2 # S4 is calculated according to # imgabs1 #, the basic lance position Hbase (t) is calculated according to the dynamic oxygen demand # imgabs3 #, and the lance position compensation amount delta H (t) is calculated according to E300 (t); and S5, calculating the final gun position H (t) according to the delta H (t). Through cooperative control of the dynamic oxygen amount and the lance position, the method adapts to fluctuation of raw material components, the hit rate of the end point carbon content is increased to 96% from 85% of a traditional method, and the temperature control precision is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of steel smelting, and particularly relates to a dynamic control method for a converter oxygen lance. Background Art

[0002] In the traditional converter steelmaking process, operations and controls mainly rely on manual experience. Operators need to manually adjust the oxygen flow according to parameters such as the temperature and composition of the molten steel. This method has many drawbacks. On the one hand, the accuracy and stability of manual operations are difficult to guarantee, and differences in the technical levels of different operators will lead to large fluctuations in steelmaking quality. On the other hand, manual operation efficiency is low and cannot meet the requirements of modern large-scale and high-efficiency steelmaking production. In addition, manual operation also has problems such as high labor intensity and high safety risks. For this reason, automated smelting technologies have been developed, but there are the following problems in the control of the converter oxygen lance in current automated smelting: the lance position highly depends on manual experience presetting and cannot adapt to fluctuations in raw material composition; the calculation of the temperature change rate uses the single-point difference method, the adjustment delay is greater than 15 seconds, the oxygen volume, lance position, and slag melting state are independently controlled, and the end-point carbon hit rate is less than 85%. Summary of the Invention

[0003] The purpose of the present invention is to provide a dynamic control method for a converter oxygen lance to solve the problems existing in the prior art.

[0004] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0005] A dynamic control method for a converter oxygen lance includes the following steps:

[0006] S1. Real-time collect molten steel composition data {Ci(t)}, molten steel temperature data T(t), and acoustic energy signal data E 300 (t);

[0007] S2. Calculate the temperature change rate according to T(t)

[0008] S3. Calculate the dynamic oxygen demand according to

[0009] S4. Calculate the basic lance position H (t), and calculate the lance position compensation amount ΔH(t) according to E base (t); 300 (t).

[0010] S5. Calculate the final lance position H(t) according to ΔH(t).

[0011] Further, in step S1, the molten steel composition data {C i(t) The concentration time-series data of at least C, Si, and Mn elements collected in real time by a laser-induced breakdown spectrometer, with a sampling frequency ≥ 10 Hz, where: i represents the molten steel composition element, i = 1, 2, 3 correspond to C, Si, and Mn elements in the molten steel respectively, t is the current moment, and C i (t) is the concentration of element i at moment t;

[0012] The molten steel temperature data T(t) is collected by an infrared thermometer, and the collection time interval Δt = 1 s;

[0013] The acoustic energy signal data E 300 (t) is collected by an acoustic sensor, and the threshold E th = 50 dB.

[0014] Furthermore, the calculation method of the temperature change rate in step S2 is as follows:

[0015] When |ΔT| ≤ 5 °C:

[0016]

[0017] When |ΔT| > 5 °C:

[0018]

[0019] Where: T(t) is the measured value of the molten steel temperature at moment t, Δt is the sampling time interval, ΔT is the temperature difference between adjacent sampling points, t + nΔt is the time offset point, and n ∈ [-2, +2].

[0020] Furthermore, the calculation formula for the dynamic oxygen demand in step S3 is as follows:

[0021]

[0022] Where: is the oxygen flow demand value at moment t, with the unit Nm 3 / min, α i is the weight coefficient of element i, C i (t - kΔt) is the concentration measurement value of element i, t is the current moment, k is the time-series offset coefficient of the sliding window, k = 0, 1, 2, 3, 4, Δt is the sampling time interval, β is the temperature change sensitivity coefficient, with the unit Nm 3 / (min·°C / s), is the molten steel temperature change rate, with the unit °C / s, e(τ) is the residual function, and τ is the integration time window.

[0023] Furthermore, the calculation formula for the basic lance position H base (t) is as follows:

[0024]

[0025] Among them, H0 is the gun position of the process reference, and Q ref is the reference oxygen content, which is the standard oxygen flow value preset according to the process requirements of the steel grade and the smelting stage during the converter steelmaking process. The unit is Nm 3 / min;

[0026] The calculation formula for the gun position compensation amount ΔH(t) is:

[0027]

[0028] Among them: E th is the threshold value, and the value is 50.

[0029] Furthermore, the calculation formula for the final gun position H(t) in step S5 is: H(t) = H base (t) + ΔH(t).

[0030] The present invention has the following beneficial effects:

[0031] 1. Through the coordinated control of dynamic oxygen content and gun position, the present invention adapts to the fluctuations of raw material components, and the hit rate of the end carbon content is increased from 85% of the traditional method to 96%, and the temperature control accuracy is improved.

[0032] 2. When it is detected that the 300Hz sound energy signal exceeds the threshold value, the gun lowering and oxygen content adjustment are automatically triggered, thereby reducing the occurrence rate of splashing.

[0033] 3. Automatically control the oxygen lance dynamically with less manual intervention, avoiding various production problems caused by large preset errors in manual experience, and improving the standardized smelting level.

[0034] 4. Precise oxygen content control reduces overblowing, thereby reducing the oxygen consumption per ton of steel and saving production costs. Specific embodiments

[0035] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further elaborates on the present invention in detail with reference to specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Embodiment 1:

[0037] A method for dynamically controlling the oxygen lance of a converter includes the following steps:

[0038] S1. Real-time collect molten steel composition data {Ci(t)}, molten steel temperature data T(t), and sound energy signal data E 300 (t).

[0039] Molten steel composition data {C i (t)} is the time-series concentration data of at least C, Si, and Mn elements collected in real time by a laser-induced breakdown spectrometer, with a sampling frequency ≥ 10 Hz, where: i represents the molten steel composition element, i = 1, 2, 3 correspond to C, Si, and Mn elements in the molten steel respectively, t is the current moment, and C i (t) is the concentration of element i at moment t;

[0040] The molten steel temperature data T(t) is collected by an infrared thermometer, and the collection time interval Δt = 1 s;

[0041] Acoustic energy signal data E 300 (t) is collected by an acoustic sensor, and the threshold E th = 50 dB.

[0042] S2. Calculate the temperature change rate based on T(t)

[0043] Temperature change rate The calculation method is as follows:

[0044] When |ΔT| ≤ 5 °C:

[0045]

[0046] When |ΔT| > 5 °C:

[0047]

[0048] Where: T(t) is the measured value of the molten steel temperature at moment t, Δt is the sampling time interval, ΔT is the temperature difference between adjacent sampling points, and t + nΔt is the time offset point, n ∈ [-2, +2].

[0049] During the stable decarburization period, the working conditions are relatively stable. The detected temperature sequence is [1520.0, 1520.3, 1520.7, 1521.0, 1521.2] °C. Since |1521.2 - 1521.0| = 0.2 °C < 5 °C, it is judged that the temperature change is relatively gentle. Therefore, the five-point method is used for calculation to ensure accuracy. At this time Since five-point data needs to be detected, the temperature change rate error is controlled within ±0.15 °C / s, and at the same time, the slight jitter of the oxygen lance is avoided to improve the accuracy of the end-point carbon control, but there is a 2-s calculation delay.

[0050] During smelting, through the dynamic switching of the temperature change rate calculation method, both accuracy and response speed can be taken into account according to different working conditions. For example, during the smelting process, due to the introduction of scrap steel impurities or when high-silicon iron ore accidentally mixes into the iron-making raw materials, the silicon content in the molten iron suddenly increases by 0.6%, resulting in a rapid temperature rise. At this time, |ΔT| = 8°C > 5°C, and it immediately switches to the three-point method for rapid response, increasing the oxygen content by 8% within 1 s, thereby avoiding splashing. After the temperature stabilizes, it automatically switches back to the five-point method.

[0051] S3. According to Calculate the dynamic oxygen demand

[0052] The dynamic oxygen demand The calculation formula is:

[0053]

[0054] Where: is the oxygen flow demand value at time t, with the unit Nm 3 / min, ɑ i is the weight coefficient of element i, C i (t - kΔt) is the concentration measurement value of element i, t is the current time, k is the time sequence offset coefficient of the sliding window, k = 0, 1, 2, 3, 4, Δt is the sampling time interval, β is the temperature change sensitivity coefficient, with the unit Nm 3 / (min·°C / s), is the molten steel temperature change rate, with the unit °C / s, e(τ) is the residual function, and τ is the integration time window.

[0055] During the smelting process, the decarburization reaction of element C dominates the oxygen consumption, the oxidation heat release of element Si assists in temperature control, and the oxidation of element Mn fine-tunes the slag state. Therefore, different values are assigned to α i . i represents the molten steel composition element. i = 1, 2, 3 correspond to elements C, Si, and Mn in the molten steel respectively. α1 = 0.78 ± 0.05, α2 = 0.15 ± 0.03, α3 = 0.07 ± 0.02. The assignment of the temperature change sensitivity coefficient β needs to consider the reaction rate and heat balance, and is adjusted according to the characteristics of the smelting stage. Historical data of multiple heats are required for calibration. In this embodiment, β = 1.1.

[0056] Calculate the dynamic oxygen demand When calculating, take the 5-point moving average concentration for each element, that is, the current time + the past 4 seconds, and multiply by the respective element weight coefficient α i , to obtain the component term; is the temperature term; Integrate the residuals in the 30-second window to obtain the residual term.

[0057] If at a certain moment during the stable decarbonization period, the moving average of the C concentration is 0.25 wt%, the moving average of the Si concentration is 0.12 wt%, the moving average of the Mn concentration is 0.18 wt%, the temperature change rate is 0.48 °C / s, and the residual integral is 0.10 wt%·s, then:

[0058] The component term is: 0.78×0.25 + 0.15×0.12 + 0.07×0.18 = 0.195 + 0.018 + 0.0126 = 0.2256 Nm 3 / min;

[0059] The temperature term is: 1.1×0.48 = 0.528 Nm 3 / min;

[0060] The residual term is: 0.6×0.10 = 0.06 Nm 3 / min;

[0061] It is necessary to slightly increase by about 0.8 Nm 3 / min of oxygen to maintain the reaction rate.

[0062] S4. According to the dynamic oxygen demand Calculate the basic lance position H base (t), and calculate the lance position compensation amount ΔH(t) according to E 300 (t).

[0063] The formula for the basic lance position H base (t) is:

[0064]

[0065] Where H0 is the process reference lance position, Q ref is the reference oxygen amount, which is the standard oxygen flow value preset according to the steel type process requirements and the smelting stage during converter steelmaking, with the unit of Nm 3 / min. H0 is set to 1500 mm, and Q ref is set to 8000 Nm 3 / min.

[0066] H base (t) = 1500 + 0.15×(0.8136 - 8000) = 1500.12 ≈ 1500 mm. According to the calculated oxygen amount compensation, it is extremely small at only 0.8136, and the lance position does not need to be adjusted.

[0067] The formula for the lance position compensation amount ΔH(t) is:

[0068]

[0069] Where: E this the threshold value, which is 50. At a certain time t, the sound energy signal E 300 (t) = 48db.

[0070] The sound energy is below the threshold and the gun needs to be slightly lifted to promote slag removal.

[0071] S5. Calculate the final gun position H(t) according to ΔH(t). H(t) = H base (t)+ΔH(t)=1500.12+4.9=1504.9mm.

[0072] Embodiment 2:

[0073] This embodiment provides a method for dynamically controlling a converter oxygen lance. The method steps are basically the same as those in Embodiment 1, except that:

[0074] S2. At the beginning of oxygen blowing, the temperature sequence detected was [1480.0, 1492.5, 1505.0]℃, due to:

[0075] |1505.0-1492.5|=12.5℃>5℃, the temperature change is judged to be more drastic, so the three-point method is used to calculate to ensure a quick response. Since only three points of data need to be detected, the calculation delay is shortened to 1s, thereby quickly responding to sudden temperature changes and preventing splashing caused by calculation delays, but the calculation accuracy is ±0.35℃ / s.

[0076] S3. At the beginning of oxygen blowing, at a certain moment, the sliding average of C concentration is 0.3wt%, the sliding average of Si concentration is 0.25wt%, the sliding average of Mn concentration is 0.20wt%, the temperature change rate is 12.5℃ / s, the residual integral is 0.25wt%·s, β=1.15, then:

[0077] The composition is: 0.78×0.30+0.15×0.25+0.07×0.20=0.234+0.0375+0.014=0.2855Nm 3 / min;

[0078] The temperature term is: 1.2×12.5=15.00Nm 3 / min;

[0079] The residual term is: 0.6×0.25=0.15Nm 3 / min;

[0080] The oxygen volume needs to be increased significantly by about 15.4Nm 3 / min.

[0081] S4, H0 are set to 1800mm, Q refSet to 8000 Nm 3 / min, E 300 E(t) = 62 db.

[0082] H base H(t) = 1800 + 0.15(15.4355 - 8000) ≈ 1802.3 mm. The oxygen content increase requires raising the lance to expand the reaction zone, but the amplitude is small.

[0083] The sound energy exceeds the standard, and the lance needs to be lowered to suppress the foamy slag.

[0084] S5, H(t) = 1802.3 - 21.5 = 1780.8 mm.

[0085] The above embodiments merely describe the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope of the present invention.

[0086] The technologies, shapes, and structures not detailed in the present invention are all well-known technologies.

Claims

1. A dynamic control method for a converter oxygen lance, characterized in that, including the following steps: S1. Real-time collect molten steel composition data {Ci(t)}, molten steel temperature data T(t), and acoustic energy signal data E 300 (t); S2. Calculate the temperature change rate according to T(t) S3. According to calculate the dynamic oxygen demand S4. According to the dynamic oxygen demand Calculate the basic lance position H base (t), and calculate the lance position compensation ΔH(t) according to E 300 (t); S5. Calculate the final lance position H(t) according to ΔH(t).

2. The dynamic control method of the converter oxygen lance according to claim 1, wherein The molten steel composition data {C i (t)} is the concentration time series data of at least C, Si, and Mn elements collected in real time by a laser-induced breakdown spectrometer, and the sampling frequency ≥ 10 Hz, where: i represents the molten steel composition element, and i = 1, 2, 3 correspond to C, Si, and Mn elements in the molten steel respectively, t is the current moment, and C i (t) is the concentration of element i at moment t; The molten steel temperature data T(t) is collected by an infrared thermometer, and the collection time interval Δt = 1 s; Acoustic energy signal data E 300 (t) is collected by an acoustic sensor, and the threshold E th = 50 dB.

3. The dynamic control method of the converter oxygen lance according to claim 2, characterized in that The temperature change rate described in step S2 is calculated as follows: When |ΔT| ≤ 5°C: When |ΔT| > 5°C: where: T(t) is the measured value of the molten steel temperature at time t, Δt is the sampling time interval, t + nΔt is the time offset point, and n ∈ [-2, +2].

4. The dynamic control method of the converter oxygen lance according to claim 3, characterized in that The dynamic oxygen demand described in step S3 The calculation formula is as follows: Wherein: is the oxygen flow rate demand value at time t, with the unit of Nm 3 / min, α i is the weight coefficient of element i, C i (t - kΔt) is the concentration measurement value of element i, t is the current time, k is the time series offset coefficient of the sliding window, k = 0, 1, 2, 3, 4, Δt is the sampling time interval, β is the temperature change sensitivity coefficient, with the unit of Nm 3 / (min·℃ / s), is the rate of change of molten steel temperature, with the unit of ℃ / s, e(τ) is the residual function, and τ is the integration time window.

5. The dynamic control method of the converter oxygen lance according to claim 4, wherein, The basic lance position H described in step S4 base (t) The calculation formula is: Among them, H0 is the gun position of the process reference, and Q ref is the reference oxygen content, which is the standard oxygen flow value preset according to the process requirements of the steel grade and the smelting stage during the converter steelmaking process, and the unit is Nm 3 / min; The calculation formula for the lance position compensation amount ΔH(t) is: Where: E th is the threshold value, with a value of 50.

6. The dynamic control method of the converter oxygen lance according to claim 5, characterized in that, The calculation formula for the final lance position H(t) described in step S5 is: H(t) = H base (t) + ΔH(t).

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