Control method for stabilizing alkalinity of blast furnace slag

Abstract

The invention discloses a control method for stabilizing the alkalinity of blast furnace slag. The method comprises the following steps: collecting blast furnace production data; calculating a blast furnace theoretical alkalinity lag period; establishing a dual-control model of a control model based on the theoretical slag alkalinity under the blast furnace tank and a control model based on the actual slag alkalinity of the blast furnace, and monitoring and analyzing the abnormal fluctuation reason of the actual slag alkalinity; and then targeted alkalinity control is carried out according to the reasons of abnormal fluctuation of alkalinity. According to the method, closed-loop control is achieved from the slag alkalinity fluctuation source and the slag fluctuation reason through the theoretical slag alkalinity and actual slag alkalinity dual-control model, the slag alkalinity fluctuation reason can be judged rapidly and comprehensively, targeted measures are taken for different reasons, the slag alkalinity is stabilized more accurately and rapidly, the blast furnace is kept stable, and the method is suitable for large-scale popularization and application. The steel production quality is improved.

Description

Technical Field

[0001] The invention relates to the field of blast furnace smelting control, and in particular to a control method for stabilizing the basicity of blast furnace slag. Background Art

[0002] Blast furnace ironmaking is a complex physical and chemical process. Iron ore, fuel and flux are loaded from the top of the furnace, and high-temperature oxygen-rich air is blown in from the bottom to burn the fuel, generating a large amount of high-temperature reducing gas that moves upward. The charge from above undergoes a series of processes such as heating, reduction, melting, and slagging during the descent process, and finally generates liquid slag and pig iron and is discharged from the blast furnace through the iron mouth. Blast furnace ironmaking is an uninterrupted continuous production process with the characteristics of large inertia and complex mechanism, so it is of great significance to keep the furnace balanced and running smoothly.

[0003] In the blast furnace smelting process, controlling the slag basicity after blast furnace smelting is an important indicator of blast furnace batching. By controlling the slag basicity, the solidification temperature and fluidity of the slag can be kept in a suitable range. First, adjust the corresponding raw material ratio according to experience based on the changes in the input raw material composition, and then calculate the corresponding control parameter value and compare it with the slag basicity. If the error requirements are met, the ratio is confirmed, and the corresponding total amount of raw materials is calculated and passed to the operator for execution. Then, the operator distributes the corresponding total amount of raw materials received to the corresponding batching bin as the batching setting value for subsequent batches. Therefore, the stable and reasonable performance of the slag can reflect the rationality of the blast furnace material configuration, which is an important guarantee for stable furnace conditions and improved steel quality.

[0004] Chinese invention patent CN 103374638 A discloses a closed-loop control method for blast furnace batching, including the following steps: pre-setting the control target of reasonable slag performance of blast furnace; blast furnace material tracking and parameter self-learning; collecting the analytical component values ​​of materials loaded into blast furnace; collecting the loading calculation information and loading time of each batch of materials on the top of blast furnace; collecting the actual molten iron analytical component values ​​and actual slag analytical component values; collecting the actual iron-discharging time, etc.; according to the preparation information, to determine whether it is necessary to change the material, generate the blast furnace material change list; collect the use status of blast furnace trough, etc.; according to the blast furnace material change list, combined with the status of the trough, etc., calculate the material cut-out amount of each trough and issue the basic automation execution. It can automatically adjust the materials loaded into the blast furnace in time according to the actual slag performance changes, compare the actual slag composition with the target slag composition, automatically distribute the trough cut-out, and issue the basic automation execution to realize the closed-loop control of blast furnace batching process. However, the frequency of raw material component testing is not enough, especially for components such as coke and flux, which are only tested once every few weeks. Theoretical alkalinity alone cannot guarantee that the alkalinity entering the blast furnace is completely stable. In addition, it takes a smelting cycle from the material under the trough to the actual slag alkalinity. The fluctuation of the actual slag alkalinity is greatly affected by the furnace conditions. The smelting cycles under different furnace conditions are also different, and the reasons for the fluctuation of alkalinity are also different. Not all alkalinity fluctuations need to be achieved by adjusting the charge structure. Summary of the invention

[0005] In order to solve the problem that slag basicity fluctuation cannot fully reflect the charge structure configuration, the present invention designs a control method for stabilizing blast furnace slag basicity. Through the dual control model of theoretical slag basicity and actual slag basicity, closed-loop control is achieved from two aspects: the source of slag basicity fluctuation and the cause of slag fluctuation, so as to stabilize the blast furnace slag system and maintain the stability of the blast furnace.

[0006] To achieve the above object, the present invention provides a method for controlling the basicity of slag in a blast furnace, comprising the following steps: S1 collects blast furnace production data; S2 calculates the hysteresis period of theoretical basicity of blast furnace; S3 establishes a dual blast furnace slag basicity control model to monitor and analyze the causes of abnormal fluctuations in actual slag basicity; S4 controls the basicity according to the actual cause of abnormal fluctuation of slag basicity.

[0007] Furthermore, the step S1 is specifically as follows: S11 collects the composition of various types of ores, fuels and fluxes entering the blast furnace; S12 sets the theoretical slag basicity and the theoretical slag basicity control range according to the charge composition; S13 collects the heat load and heat load standard deviation of the blast furnace per hour, and collects the control range of the heat load and heat load standard deviation; S14 collects the actual slag basicity, molten iron temperature, ferrous oxide content in the slag of the blast furnace, and the control range of the actual slag basicity, molten iron temperature, and ferrous oxide content in the slag.

[0008] Furthermore, the step S2 is specifically as follows: S21 obtains the smelting cycle required from the charge entering the blast furnace to the slag; S21 Regularly compare the actual slag basicity with the theoretical slag basicity; S23 calculates the correlation coefficient between the actual slag basicity and the theoretical slag basicity at different lag times; S24 compares the correlation coefficients obtained at different lag times and selects the correlation coefficient with the largest absolute value; The lag time corresponding to the correlation coefficient with the largest absolute value of S25 is the actual lag time of the slag.

[0009] Specifically, in step S23, the correlation coefficient calculation formula is: Where: Cov(R2, B2) is the covariance of R2 and B2; Var[R2] and Var[B2] are the variances of R2 and B2 respectively; R2 is the theoretical slag basicity, and B2 is the actual slag basicity.

[0010] The lag time can reflect the activity level of the furnace. The allowable range of the lag period is set to T=T0+2. When the lag period is within the allowable range, that is, T≤T0+2, it means that the furnace is active; when the lag period exceeds the allowable range, that is, T>T0+2, it means that the furnace is inactive, where T is the lag period, T0 is the theoretical smelting period, and the number 2 means a lag time of 2 hours.

[0011] Furthermore, in step S3, the dual blast furnace slag basicity control model includes a control model based on the theoretical slag basicity under the blast furnace trough and a control model based on the actual slag basicity of the blast furnace.

[0012] Furthermore, the control model based on the theoretical slag basicity under the blast furnace tank is: S31 compares the error between the ratio under the blast furnace tank and the set ratio; S32 When the actual error is higher than the set error, adjust the charge structure ratio; when the actual error is within the set error range, keep the charge structure ratio unchanged; S33 calculates the theoretical slag basicity under the tank; S34 compares the theoretical slag basicity of each batch of materials under the trough with the set theoretical slag basicity. If it exceeds the control range of the set theoretical slag basicity, the blast furnace batching model is adjusted to adjust the flux material.

[0013] Specifically, the method for calculating the theoretical alkalinity under the trough is: collecting the weight of raw materials discharged from each bin under the blast furnace trough, calculating the actual weight of each batch of materials and the corresponding proportion, and matching the charge name, weight and corresponding components under the trough in real time, calling the blast furnace batching model, and calculating the theoretical slag alkalinity under the trough in real time according to the principle of conservation of mass.

[0014] Furthermore, the control model based on the actual blast furnace slag basicity includes a blast furnace actual slag basicity excessively high model and a blast furnace actual slag basicity insufficient model, and the furnace activity is judged through subsequent cycles; The basis for judging that the actual blast furnace slag basicity is too high is that the actual blast furnace slag basicity is higher than the upper limit of the actual slag basicity for two consecutive times; The criterion for judging whether the actual blast furnace slag basicity is too low is that the actual blast furnace slag basicity is lower than the lower limit of the actual slag basicity for two consecutive times.

[0015] Specifically, the actual blast furnace slag basicity high model includes the following situations: The molten iron temperature is higher than the upper control limit, the heat load and its deviation value are within the normal range, and the hysteresis period is within the allowable range, that is, T≤T0+2, indicating that the furnace is active and normal. The cause is determined to be that the molten iron temperature is too high. The blast furnace batching model is started, the blast furnace coal quantity is adjusted, the blast furnace fuel ratio is reduced, and the material list is sent to the blast furnace under-tank controller for automatic execution; The molten iron temperature is within the normal range, the heat load and its standard deviation are both higher than the upper limit, and the hysteresis period is within the allowable range, that is, T≤T0+2, indicating that the furnace is active and normal. The cause is determined to be slag shedding. The blast furnace batching model is started, the amount of coke is replenished, and the material list is sent to the blast furnace under-tank controller for automatic execution; The molten iron temperature is within the normal range, the heat load and its standard deviation are both higher than the upper limit, and the slag basicity hysteresis period exceeds the allowable range, that is, T>T0+2, and the furnace is judged to be inactive, so coke is added, and the system automatically warns the operator that the furnace is not active and needs to withdraw the ore batch and increase the air volume; The molten iron temperature is within the normal range, the heat load and its standard deviation are also within the normal range, and the lag period is within the allowable range, that is, T≤T0+2, indicating that the internal activity of the furnace is normal. The cause is determined to be the blast furnace burden deviation. The blast furnace burden model is started, the blast furnace burden is adjusted, and the material list is sent to the blast furnace trough controller for automatic execution.

[0016] Specifically, the actual low slag basicity model of the blast furnace includes the following situations: The molten iron temperature is lower than the upper control limit, the heat load and its deviation value are within the normal range, and the hysteresis period is within the allowable range, that is, T≤T0+2, indicating that the furnace is active and normal. The cause is that the molten iron temperature is too low. The blast furnace batching model is started, the blast furnace coal quantity is adjusted, the blast furnace fuel ratio is reduced, and the material list is sent to the blast furnace tank controller for automatic execution; The molten iron temperature is within the normal range, the heat load and its standard deviation are also within the normal range, and the lag period is within the allowable range, that is, T≤T0+2, indicating that the internal activity of the furnace is normal. The cause is determined to be the blast furnace burden deviation. The blast furnace burden model is started, the blast furnace burden is adjusted, and the material list is sent to the blast furnace trough controller for automatic execution.

[0017] After the slag basicity control model is established, the actual slag basicity is monitored in real time. When the blast furnace slag basicity is abnormal, the reason for the change in slag basicity is determined according to the established model. Based on the reason for the basicity fluctuation, different measures are taken to make adjustments. If the slag basicity is caused by changes in the chemical composition of the raw materials, the basicity is adjusted by adjusting the charge ratio; if it is caused by inaccurate feeding, the weighing equipment is checked and calibrated, and the charge ratio is recalculated; if it is caused by furnace temperature fluctuations, corresponding measures to increase or decrease heat should be taken according to the furnace temperature development trend; if it is caused by slag skin falling off, the airflow is stabilized.

[0018] Beneficial effects of the present invention: A dual closed-loop control system for the theoretical basicity under the blast furnace trough and the actual slag basicity is designed to achieve closed-loop control from two aspects: the source of basicity fluctuation and the different causes of basicity fluctuation. When changes in slag basicity are monitored, the reasons for the fluctuations can be analyzed to quickly and comprehensively determine the reasons, and targeted adjustments can be made to more accurately stabilize the slag basicity, maintain the stability of the blast furnace, and improve the quality of steel production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention is a flow chart of a control method for stabilizing the basicity of blast furnace slag. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Reference Figure 1 As shown, an embodiment of a control method for stabilizing the basicity of blast furnace slag is provided, comprising the following steps: S1 collects blast furnace production data; S2 calculates the hysteresis period of theoretical slag basicity of blast furnace; S3 establishes a dual blast furnace slag basicity control model to monitor and analyze the causes of abnormal fluctuations in actual slag basicity; S4 controls the basicity according to the actual cause of abnormal fluctuation of slag basicity.

[0022] In step S1, the collected data include: the charge composition of various types of ores, fuels and fluxes entering the blast furnace, the hourly heat load of the blast furnace and its standard deviation, and the actual slag basicity of the blast furnace.

[0023] The charge compositions of various types of ores, fuels and fluxes entering the blast furnace are collected. In this embodiment, based on the optimization calculation of the sintering-blast furnace integrated burden model with the goal of lowest molten iron cost / highest benefit / lowest fuel ratio, the set charge structure ratio is obtained: Wt0_sintering, Wt0_pellets, Wt0_lump ore, X0_sintering, X0_pellets, X0_lump ore, Wt0_coke, Wt0_coal, Wt0_flux, the theoretical slag basicity R2 is set, and the theoretical slag basicity control range is set: the lower limit is R2_low, and the upper limit is R2_up.

[0024] The hourly heat load TL and its standard deviation ΔTL of the blast furnace are collected. The heat load control range is: the lower limit is TL_low, and the upper limit is TL_up; the heat load standard deviation control range is: the lower limit is ΔTL_low, and the upper limit is ΔTL_up.

[0025] The actual blast furnace slag basicity B2, molten iron temperature HMT, and ferrous oxide (FeO) content in the slag are collected. The actual blast furnace slag basicity control range is: the lower limit is B2_low, and the upper limit is B2_up; the molten iron temperature control range is: the lower limit is HMT_low, and the upper limit is HMT_up; the FeO content control range in the slag is: the lower limit is FeO_low, and the upper limit is FeO_up.

[0026] In step S2, it usually takes a smelting cycle of T0 hours from the time the charge enters the blast furnace to the time the molten iron and slag are formed. When the blast furnace does not work properly and the furnace activity is insufficient, the lag period may be higher than T0. Therefore, it is necessary to perform a correlation analysis on the actual slag basicity and the theoretical slag basicity. In this embodiment, a correlation analysis is performed regularly in the background on the actual slag basicity B2 of the past 100 furnaces and the theoretical slag basicity R2 of the 100 furnaces 1 hour (lag time) before to obtain the correlation coefficient. The correlation coefficient calculation formula is: Where: Cov(R2, B2) is the covariance of R2 and B2; Var[R2] and Var[B2] are the variances of R2 and B2 respectively; R2 is the theoretical slag basicity, and B2 is the actual slag basicity.

[0027] The actual basicity B2 of the past 100 furnaces was analyzed with the theoretical slag basicity R2 of the 100 furnaces 2 hours (lag time), 3 hours... until 4T0 (lag time) hours ago according to the above correlation coefficient calculation method, and the correlation coefficient was calculated. , … , and take to The lag time corresponding to the correlation coefficient with the largest absolute value is the actual lag period T of the slag.

[0028] The lag time can reflect the activity level of the furnace. The allowable range of the lag period is set to T=T0+2. When the lag period is within the allowable range, that is, T≤T0+2, it means that the furnace is active. When the subsequent period exceeds the allowable range, that is, T>T0+2, it means that the furnace is inactive, where T is the lag period, T0 is the theoretical smelting period, and the number 2 means a lag time of 2 hours.

[0029] In step S3, the dual blast furnace slag basicity control model includes a control model based on the theoretical slag basicity under the blast furnace trough and a control model based on the actual slag basicity of the blast furnace.

[0030] Since the theoretical basicity is reflected by the actual slag basicity after a smelting cycle, and the time interval for detecting the composition of the raw fuel is relatively long, it is inevitable that undetected abnormal components will enter the blast furnace. In addition, affected by the blast furnace slag skin falling off, abnormal furnace temperature and other conditions, the actual slag basicity will fluctuate abnormally. Therefore, the blast furnace basicity closed-loop control model is divided into two parts: the closed-loop control model of the theoretical basicity under the trough, which can stabilize the basicity of the source of the charge; the closed-loop control model based on the actual blast furnace slag basicity fluctuation, analyzes the reasons for the fluctuation of the slag basicity, and carries out targeted control.

[0031] The first slag basicity closed-loop control model of this embodiment is based on the closed-loop control of the theoretical basicity under the blast furnace tank: First, corrections are made based on the proportion structure of the charge under the trough.

[0032] Compare the error between the ratio under the blast furnace trough and the set ratio, E_sintering = X_sintering-X0_sintering, E_pellets = X_pellets-X0_pellets, E_lumps = X_lumps-X0_lumps. When the error E_sintering, E_pellets or E_lumps exceeds the set error E0, restart the blast furnace batching model to get a new charge structure ratio. If the actual error of the raw material is within the set error range, keep the charge structure ratio of the raw material unchanged.

[0033] Secondly, the theoretical slag basicity R2_new under the trough is calculated based on the corrected charge structure ratio.

[0034] Collect the weight of raw materials discharged from each bin under the blast furnace trough, calculate the actual weight of each batch of materials: Wt_sintering, Wt_pellets, Wt_lump ore, and the corresponding proportions: X_sintering, X_pellets, X_lump ore. And match the name, weight and corresponding components of the charge in real time under the trough, call the blast furnace batching model, and calculate the theoretical slag basicity R2_new under the trough in real time according to the principle of mass conservation. The calculation formula is: R2_new = (Wt_Sinter * CaO_Sinter + Wt_Pellet * CaO_Pellet + Wt Lump Ore * CaO_Lump Ore + Wt_Fuel * CaO_Fuel + Wt_Flux * CaO_Flux) / (Wt_Sinter * SiO2_Sinter + Wt_Pellet * SiO2_Pellet + Wt Lump Ore * SiO2_Lump Ore + Wt_Fuel * SiO2_Fuel + Wt_Flux * SiO2_Flux).

[0035] Finally, the closed-loop control based on the theoretical basicity R2_new under the bin.

[0036] For each batch of materials under the bin, when it is judged that the theoretical basicity R2_new exceeds the upper control limit, i.e., R2_new > R2_up, or R2_new is lower than the lower control limit, i.e., R2_new < R2_low, the blast furnace burdening model is started to adjust the flux consumption, and the burden structure is sent to the PLC under the bin for execution.

[0037] The second slag basicity closed-loop control model of this embodiment, the closed-loop control model based on the actual slag basicity of the blast furnace includes: the model of too high actual slag basicity of the blast furnace and the model of too low actual slag basicity of the blast furnace.

[0038] In the embodiment of the present invention, the judgment method for too high actual slag basicity of the blast furnace is: if the actual slag basicities B2_i and B2_i-1 of two consecutive furnaces are higher than the upper limit, i.e., B2_i > B2_up and B2_i-1 > B2_up, or the actual slag basicity B2_i of a single furnace > (B2_up + 0.02), then the control model for too high actual slag basicity is started.

[0039] The first embodiment of the actual slag basicity closed-loop control model: If the hot metal temperature HMT is higher than the upper control limit, i.e., HMT > HMT_up, the heat load and its standard deviation are within the normal range, i.e.: TL_low < TL < TL_up and ΔTL_low < ΔTL < ΔTL_up, and the lag period is within the allowable range, i.e., T ≤ T0 + 2, indicating that the activity inside the hearth is normal, then it is judged that the too high actual slag basicity is caused by the too high hot metal temperature. The blast furnace burdening model is started to adjust the blast furnace coal amount, reduce the blast furnace fuel ratio to reduce heat, and the charging list is sent to the blast furnace PLC (controller) under the bin for automatic execution.

[0040] The second embodiment of the closed-loop control model for the actual slag basicity: If the hot metal temperature HMT is within the normal range, i.e., HMT_low < HMT < HMT_up, but the heat load and its standard deviation during this period are both higher than the upper limit, i.e., TL > TL_up and ΔTL > ΔTL_up, and FeO in the slag > FeO_up, and the lag period is within the allowable range, i.e., T ≤ T0 + 2, indicating that the activity inside the blast furnace hearth is normal, then it is judged that the excessive actual slag basicity is caused by the shedding of the slag skin. Start the blast furnace burdening model, supplement the coke amount to increase the heat, and send the burden list to the PLC (controller) under the blast furnace bunker for automatic execution.

[0041] The third embodiment of the closed-loop control model for the actual slag basicity: If the hot metal temperature HMT is within the normal range, i.e., HMT_low < HMT < HMT_up, but the heat load and its standard deviation during this period are both higher than the upper limit, i.e., TL > TL_up and ΔTL > ΔTL_up, and FeO in the slag > FeO_up, and the lag period of the slag basicity exceeds the allowable range, i.e., T > T0 + 2, then it is judged that the current blast furnace hearth is inactive, and an early warning signal is automatically sent to prompt the staff to pay attention, supplement coke and adjust the operation regime.

[0042] The fourth embodiment of the closed-loop control model for the actual slag basicity: If the hot metal temperature is within the normal range, i.e., HMT_low < HMT < HMT_up, and the heat load and its standard deviation are also within the normal range, i.e., TL > TL_up and ΔTL > ΔTL_up, and the lag period is within the allowable range, i.e., T ≤ T0 + 2, indicating that the activity inside the blast furnace hearth is normal, then it is judged that the excessive actual slag basicity is caused by the unreasonable burden ratio. Start the blast furnace burdening model, reduce x on the basis of the theoretical basicity R2, where x = B2 - B2_up, adjust the fluxing agent amount, including silica, serpentine, magnesite, etc., and send the burden list to the PLC (controller) under the blast furnace bunker for automatic execution.

[0043] In the embodiments of the present invention, the judgment method for the too low actual slag basicity of the blast furnace is as follows: If the actual slag basicity B2_i and B2_i - 1 of two consecutive furnaces are lower than the lower limit, i.e., B2_i < B2_low and B2_i - 1 < B2_low, or the single-furnace basicity B2_i < (B2_up - 0.02), start the analysis module for too low basicity.

[0044] The fifth embodiment of the closed-loop control model for the actual slag basicity: If the hot metal temperature HMT is lower than the control lower limit, i.e., HMT < HMT_low, the heat load and its standard deviation are within the normal range, i.e., TL_low < TL < TL_up and ΔTL_low < ΔTL < ΔTL_up, and the lag period is within the allowable range, i.e., T ≤ T0 + 2, indicating that the activity inside the hearth is normal, then it is judged that the too low actual slag basicity is caused by the too low hot metal temperature. Start the blast furnace burdening model, adjust the blast furnace coal volume, reduce the blast furnace fuel ratio, and send the burden list to the PLC under the blast furnace bunker for automatic execution.

[0045] The sixth embodiment of the closed-loop control model for the actual slag basicity: If the hot metal temperature HMT is within the normal range, i.e., HMT_low < HMT < HMT_up, and the heat load and its standard deviation are also within the normal range, i.e., TL_low < TL < TL_up and ΔTL_low < ΔTL < ΔTL_up, and the lag period is within the allowable range, i.e., T ≤ T0 + 2, indicating that the activity inside the hearth is normal, then it is judged that the too high actual slag basicity is caused by the unreasonable burden ratio. Start the blast furnace burdening model and reduce x on the basis of the theoretical basicity R2, where x = B2_low - B2, and adjust the flux, including silica, serpentine, and magnesite.

[0046] In the closed-loop control model based on the actual blast furnace slag basicity, a program for judging the reasons for the change in slag basicity is carried out. It not only judges the real reasons for the change in slag basicity from the temperature and heat load, but also reflects the activity degree of the hearth through the lag period. Under the condition of hearth activity, through different changes in temperature and heat load, it is judged which specific factor among the following reasons such as too high hot metal temperature, slag skin shedding, unreasonable burdening, and too low hot metal temperature causes the abnormal slag basicity, and targeted adjustments are made according to the specific reasons.

[0047] When the blast furnace slag basicity is abnormal, different measures are taken for adjustment based on the reasons for the alkalinity fluctuation. If the slag basicity is caused by the change in the chemical composition of the raw materials, the burden ratio is adjusted to adjust the alkalinity; if it is caused by inaccurate charging, the weighing equipment is inspected and calibrated, and then the burden ratio is recalculated; if it is caused by the furnace temperature fluctuation, corresponding measures to increase or decrease the heat should be taken according to the furnace temperature development trend; if it is caused by the slag skin shedding, the gas flow is stabilized.

[0048] Through the design scheme of the present invention, it is possible to quickly and comprehensively judge the reasons for the fluctuation of the slag basicity, take targeted measures for different reasons, more accurately and quickly stabilize the slag basicity, maintain the stability of the blast furnace, and improve the quality of steel production.

[0049] Although the preferred implementation cases of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms of specific changes without departing from the scope of protection of the invention spirit and claims, which all fall within the scope of protection of the present invention.

Claims

1. A method for controlling the basicity of stabilizing blast furnace slag, characterized in that: The following steps are involved: S1 collects blast furnace production data; S2 calculates the hysteresis period of theoretical basicity of blast furnace; S3 establishes a dual blast furnace slag basicity control model to monitor and analyze the causes of abnormal fluctuations in actual slag basicity; S4 controls the basicity according to the actual cause of abnormal fluctuation of slag basicity.

2. The method for controlling the stable blast furnace slag basicity according to claim 1, characterized in that: The step S1 is specifically as follows: S11 collects the composition of various types of ores, fuels and fluxes entering the blast furnace; S12 sets the theoretical slag basicity and the theoretical slag basicity control range according to the charge composition; S13 collects the heat load and heat load standard deviation of the blast furnace per hour, and collects the control range of the heat load and heat load standard deviation; S14 collects the actual slag basicity, molten iron temperature, ferrous oxide content in the slag of the blast furnace, and the control range of the actual slag basicity, molten iron temperature, and ferrous oxide content in the slag.

3. The method for controlling the stable blast furnace slag basicity according to claim 1, characterized in that: The step S2 is specifically as follows: S21 obtains the smelting cycle required from the charge entering the blast furnace to the slag; S21 Regularly compare the actual slag basicity with the theoretical slag basicity; S23 calculates the correlation coefficient between the actual slag basicity and the theoretical slag basicity at different lag times; S24 compares the correlation coefficients obtained at different lag times and selects the correlation coefficient with the largest absolute value; The lag time corresponding to the correlation coefficient with the largest absolute value of S25 is the actual lag time of the slag.

4. The method for controlling the stable blast furnace slag basicity according to claim 3, characterized in that: In step S23, the correlation coefficient calculation formula is: Where: Cov(R2, B2) is the covariance of R2 and B2; Var[R2] and Var[B2] are the variances of R2 and B2 respectively; R2 is the theoretical slag basicity, and B2 is the actual slag basicity.

5. The method for controlling the stable blast furnace slag basicity according to claim 1, characterized in that: In step S3, the blast furnace slag basicity control model includes a control model based on the theoretical slag basicity under the blast furnace tank and a control model based on the actual slag basicity of the blast furnace.

6. The method for controlling the stable blast furnace slag basicity according to claim 5, characterized in that: The control model based on the theoretical slag basicity under the blast furnace tank is: S31 compares the error between the ratio under the blast furnace tank and the set ratio; S32 When the actual error is higher than the set error, adjust the charge structure ratio; when the actual error is within the set error range, keep the charge structure ratio unchanged; S33 calculates the theoretical slag basicity under the tank; S34 compares the theoretical slag basicity of each batch of materials under the trough with the set theoretical slag basicity. If it exceeds the control range of the set theoretical slag basicity, the blast furnace batching model is adjusted to adjust the flux dosage.

7. The method for controlling the stable blast furnace slag basicity according to claim 6, characterized in that: The method for calculating the theoretical basicity under the trough is as follows: collecting the weight of raw materials discharged from each bin under the blast furnace trough, calculating the actual weight of each batch of materials and the corresponding proportion, and matching the name, weight and corresponding components of the charge under the trough in real time, calling the blast furnace batching model, and calculating the theoretical slag basicity under the trough in real time according to the principle of conservation of mass.

8. The method for controlling the stable blast furnace slag basicity according to claim 5, characterized in that: The control model based on the actual blast furnace slag basicity includes a blast furnace actual slag basicity excessively high model and a blast furnace actual slag basicity low model; The basis for judging that the actual blast furnace slag basicity is too high is that the actual blast furnace slag basicity is higher than the upper limit of the actual slag basicity for two consecutive times; The criterion for judging whether the actual blast furnace slag basicity is too low is that the actual blast furnace slag basicity is lower than the lower limit of the actual slag basicity for two consecutive times.

9. The method for controlling the stable basicity of blast furnace slag according to claim 8, characterized in that: The actual blast furnace slag basicity excess model includes the following situations: The molten iron temperature is higher than the upper control limit, the heat load and its deviation value are within the normal range, and the hysteresis period is within the allowable range, indicating that the furnace is active and normal. The cause is determined to be that the molten iron temperature is too high. The blast furnace batching model is started, the blast furnace coal quantity is adjusted, the blast furnace fuel ratio is reduced, and the material list is sent to the blast furnace under-tank controller for automatic execution; The molten iron temperature is within the normal range, the heat load and its standard deviation are both above the upper limit, and the hysteresis period is within the allowable range, indicating that the furnace is active and normal. The cause is determined to be slag shedding. The blast furnace batching model is started, the amount of coke is replenished, and the material list is sent to the blast furnace tank controller for automatic execution; If the molten iron temperature is within the normal range, the heat load and its standard deviation are both above the upper limit, and the slag basicity hysteresis period exceeds the allowable range, coke is added, and the system automatically issues an early warning, prompting the operator that the current furnace is not active and that the ore batch needs to be withdrawn and the air volume needs to be increased; The molten iron temperature is within the normal range, the heat load and its standard deviation are also within the normal range, and the lag period is within the allowable range, indicating that the internal activity of the furnace is normal. The cause is determined to be the blast furnace burden deviation. The blast furnace burden model is started, the blast furnace burden is adjusted, and the material list is sent to the blast furnace trough controller for automatic execution.

10. The method for controlling the stable basicity of blast furnace slag according to claim 8, characterized in that: The actual low slag basicity model of the blast furnace includes the following situations: The molten iron temperature is lower than the upper control limit, the heat load and its deviation value are within the normal range, and the hysteresis period is within the allowable range, indicating that the furnace is active and normal. The cause is determined to be that the molten iron temperature is too low. The blast furnace batching model is started, the blast furnace coal quantity is adjusted, the blast furnace fuel ratio is reduced, and the material list is sent to the blast furnace under-tank controller for automatic execution; The molten iron temperature is within the normal range, the heat load and its standard deviation are also within the normal range, and the lag period is within the allowable range, indicating that the internal activity of the furnace is normal. The cause is determined to be the blast furnace burden deviation. The blast furnace burden model is started, the blast furnace burden is adjusted, and the material list is sent to the blast furnace trough controller for automatic execution.

Images