JP6658804B2 - Initial component concentration correction device, initial component concentration correction method, refining process state estimation method, and converter operation method - Google Patents

Description

  The present invention relates to an initial component concentration correction device, an initial component concentration correction method, a refining process state estimation method, and a converter operation method.

  In an ironworks, after dissolving iron ore in a blast furnace, the component concentration and temperature of the molten metal are adjusted in a refining facility. There are various types of refining equipment depending on the pretreatment equipment, converter, and secondary refining equipment and processing purpose. For example, in a converter, which is a typical example of refining equipment, impurities in the molten metal are removed and the temperature is raised by blowing oxygen into the furnace, so that the component concentration and temperature of the molten metal after blowing are within specified ranges. The control is performed as follows. However, since the oxidation reaction in the molten metal is intense and the temperature of the molten metal becomes high, it is difficult to measure the component concentration and the temperature in the molten metal every moment. For this reason, in actual operation, the molten metal during blowing is sampled, and based on the information obtained by the sampling and the reaction model, the blowing control (determination of necessary acid supply amount and coolant input amount) until the end of blowing is performed. We are doing calculations.

  If information on the component concentration and temperature of the molten metal can be continuously obtained, the processing accuracy can be improved. At present, the process information that can be continuously collected includes information on the exhaust gas (flow rate and concentration of each component) in addition to the operation amount. It is possible to estimate the amount of carbon discharged outside the furnace using the information on the exhaust gas, and it is possible to calculate the carbon component concentration in the molten metal based on the amount of discharged carbon from the material balance. However, information measured on exhaust gas generally has a large error. For example, the flow value of exhaust gas is often estimated from the pressure drop before and after an orifice (throttle) or a venturi pipe is generally installed in the exhaust gas pipe. However, since the pressure, temperature, and flow rate of the exhaust gas frequently fluctuate greatly, errors tend to increase in the above-described method. Patent Document 1 discloses that in order to deal with such a problem, a coefficient for correcting a measurement value is calculated based on past results with respect to an exhaust gas flow rate of a steel refining process, and further calculated based on a melt analysis result during blowing. A method has been proposed in which the coefficient is corrected and the carbon component concentration in the molten metal is estimated in real time based on the information.

JP-A-9-272913

  However, the method proposed in Patent Document 1 corrects the exhaust gas flow rate based on the amount of carbon in the exhaust gas and the amount of carbon reduction in the molten metal. There is also a possibility that an error will occur with respect to. In particular, the measured values of the molten metal components before the processing are due to the reaction that progresses in the molten metal from the time of component measurement to the start of the processing, and the fact that component analysis is performed on a very small sample of a large amount of molten metal where uniformity is not guaranteed. As a result, an error may occur, and the accuracy of estimating the transition of the component concentration in the molten metal may deteriorate.

  In addition to the calculation of the transition of the component concentration, there is a calculation in which the accuracy deteriorates when a large error is included in the measured value of the molten metal component before the processing. For example, in the calculation of the oxygen amount and auxiliary materials required for blowing, which is performed before the treatment (static model calculation), the measured value of the molten metal component before the treatment is used. Accuracy deteriorates. If the calculation accuracy deteriorates and the amount of oxygen to be blown or the amount of sub-material input becomes unnecessarily large, the yield deteriorates and the processing time increases. If smelting becomes necessary, the processing completion time will be greatly delayed from the plan, and in any case, productivity will be greatly impaired.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an initial component concentration correction device, an initial component concentration correction method, and a refining process state capable of improving the estimation accuracy of a component concentration transition in a molten metal. It is an object of the present invention to provide an estimation method and a converter operation method.

  In order to solve the above-described problems and achieve the object, an initial component concentration correction device according to the present invention provides, as input information, a measurement result of a component concentration of a molten metal during or after processing in a smelting facility, from the refining facility. The flow rate of the discharged exhaust gas and the measurement result of the component concentration in the exhaust gas, information on the amount of oxygen blown into the furnace of the refining facility, information on the weight and component concentration of the molten metal before the treatment, and input during the treatment An input device into which information relating to the weight of the auxiliary raw material is input, and the input information, and a measured value of the flow rate of the exhaust gas discharged from the refining facility in the past charge based on the calculation result of the balance of carbon and oxygen. A past blowing correction calculator for calculating a correction parameter for correcting the measured value of the component concentration in the exhaust gas and the measured value of the initial component concentration in the molten metal; and the input information The correction parameter, and information storage means for storing the operation information of the past charge, the input information, the operation information, the correction parameter, the measured value of the initial component concentration in the molten metal in the next charge, and the operation information of the next charge , An initial component concentration correction value for correcting the initial component concentration in the molten metal in the next charge is calculated, and the initial component concentration in the melt in the next charge is corrected using the initial component concentration correction value. And a smelting correction calculation unit.

  Further, in the initial component concentration correction device according to the present invention, in the above invention, the past blowing correction calculation unit calculates the past blowing calculation based on the component analysis value of the molten metal and the carbon content contained in the added auxiliary raw material. The evaluation function based on the difference between the carbon reduction amount in the molten metal during the specified period and the carbon amount in the exhaust gas during the blowing period and the evaluation function based on the balance of the amount of oxygen used for carbon combustion are minimized. The correction parameter is calculated as follows.

  Further, in the initial component concentration correction device according to the present invention, in the above invention, the next blowing correction calculation unit calculates the initial component concentration correction value using a regression equation in which parameters are determined based on past charges. The regression equation is characterized in that the explanatory variables include at least an initial component concentration measurement value in the molten metal in the next charge.

  Further, the initial component concentration correction method according to the present invention may include, as input information, a measurement result of a component concentration of the molten metal during or after processing in the refining facility, a flow rate of the exhaust gas discharged from the refining facility, and a component in the exhaust gas. A step of inputting information on the measurement result of the concentration, information on the amount of oxygen blown into the furnace of the refining facility, information on the weight and the component concentration of the molten metal before the processing, and information on the weight of the auxiliary material charged during the processing. And, the input information, and, based on the calculation result of the balance of carbon and oxygen, in the past charge, the measured value of the flow rate of the exhaust gas discharged from the refining equipment, the measured value of the component concentration in the exhaust gas, and, Calculating a correction parameter for correcting the measured value of the initial component concentration in the molten metal; and operating the input information, the correction parameter, and the past charge. Based on the input information, the operation information, the correction parameter, the measured value of the initial component concentration in the melt at the next charge, and the operation information of the next charge, based on the initial component concentration in the melt at the next charge. Calculating an initial component concentration correction value for correcting the initial component concentration, and correcting the initial component concentration in the molten metal in the next charge using the initial component concentration correction value.

  Further, the refining process state estimating method according to the present invention estimates a component concentration transition in the molten metal based on the initial component concentration in the molten metal at the next charge corrected by the initial component concentration correcting method of the invention. It is characterized by including a step.

  Further, the method for operating a converter according to the present invention may be configured such that the component concentration in the molten metal is determined based on the transition of the component concentration in the molten metal at the next charge, which is estimated using the refining process state estimation method of the present invention. Is adjusted within the range.

  ADVANTAGE OF THE INVENTION The initial component concentration correction apparatus and the initial component concentration correction method according to the present invention have an effect that the accuracy of estimating the transition of the component concentration in the molten metal can be improved.

FIG. 1 is a schematic diagram illustrating a configuration of the initial component concentration correction device according to the embodiment. FIG. 2 is a block diagram for explaining the content of the arithmetic processing by the arithmetic processing unit. FIG. 3 is a flowchart illustrating a flow of a process executed by the past blowing correction calculation unit. FIG. 4 is a flowchart illustrating a flow of a process executed by the next blowing correction calculation unit. Figure 5 is a graph showing the amount of oxygen Determination of middle S / L at the target carbon concentration x _C ^*. FIG. 6 is a diagram showing the relationship between the blowing time and the C concentration in the molten metal by the carbon balance calculation. FIG. 7 is a graph showing the conversion value of the standard deviation for 500 charges for the difference between the calculated oxygen amount and the actual oxygen amount in the present invention example and the comparative example.

  Hereinafter, an embodiment of the initial component concentration correction device according to the present invention will be described. The present invention is not limited by the embodiment.

[Configuration of initial component concentration correction device]
First, the configuration of the initial component concentration correction device according to the present embodiment will be described. FIG. 1 is a schematic diagram illustrating a configuration of an initial component concentration correction device 1 according to the embodiment. As shown in FIG. 1, an initial component concentration correction device 1 according to the present embodiment is a device for estimating an initial component concentration of a molten metal 101 being processed in a smelting facility 2 of the steel industry. Here, the refining facility 2 includes a converter 100, a lance 102, and a duct 104. A lance 102 is arranged on a molten metal (molten steel) 101 in the converter 100. High-pressure oxygen is ejected from the tip of the lance 102 toward the molten metal 101 below. The impurities in the molten metal 101 are oxidized by the high-pressure oxygen and taken into the slag 103 (blowing process). Above the converter 100, a duct 104 for conducting exhaust gas smoke is provided.

An exhaust gas detection unit 105 is arranged inside the duct 104. The exhaust gas detection unit 105 detects the flow rate of the exhaust gas discharged along with the blowing process and the components (for example, CO, CO ₂ , O _2, etc.) in the exhaust gas. The exhaust gas detector 105 measures the flow rate of the exhaust gas in the duct 104 based on, for example, a pressure difference before and after an orifice provided in the duct 104. Further, the exhaust gas detection unit 105 measures the concentration [%] of each component in the exhaust gas. The flow rate and the component concentration of the exhaust gas are measured, for example, every several seconds. A signal indicating the detection result of the exhaust gas detection unit 105 is sent to the control terminal 10.

  Stirring gas is blown into the molten metal 101 in the converter 100 through a vent hole 106 formed in the bottom of the converter 100. The stirring gas is an inert gas such as Ar. The injected stirring gas stirs the molten metal 101 and promotes the reaction between the high-pressure oxygen and the molten metal 101. Flow meter 107 measures the flow rate of the stirring gas blown into converter 100. Immediately before the start of blowing and after blowing, analysis of the temperature and the component concentration of the molten metal 101 is performed. Further, the temperature and the component concentration of the molten metal 101 are measured once or a plurality of times during the blowing, by taking a sample of the molten metal, and based on the measured temperature and the component concentration, the supply amount of high-pressure oxygen (acid supply Amount) and speed (acid feed rate), the flow rate of the stirring gas (flow rate of the stirring gas), and the like are determined.

  The timing for collecting the molten metal sample is determined based on a material balance / heat balance calculation or the like. For example, in the case of an operation where a molten metal sample is collected only once during blowing, the target carbon concentration and target temperature of the molten metal at the sample collection timing are set in advance, and a static model performed before blowing processing is performed. In the calculation, an upper blowing oxygen amount required to reach the target carbon concentration and the target temperature is calculated. Then, a sample is taken at the time when the upper blowing oxygen amount integrated after starting the blowing reaches the required upper blowing oxygen amount. The sampling is often performed using a device called a sublance (S / L). Hereinafter, the operation itself of collecting a molten metal sample during blowing using this apparatus will be referred to as S / L during the blowing for simplicity.

  The blowing control system to which the initial component concentration correction device 1 is applied includes a control terminal 10, the initial component concentration correction device 1, and a display device (CRT) 20 as main components. The control terminal 10 is configured by an information processing device such as a personal computer or a work station, and controls an acid supply amount, an acid supply speed, and a stirring gas flow rate so that the component concentration of the molten metal 101 falls within a desired range. Data of the actual value of the acid supply amount, the acid supply rate, and the flow rate of the stirring gas is collected.

  The initial component concentration correction device 1 is configured by an information processing device such as a personal computer or a workstation. The initial component concentration correction device 1 includes an input device 11, a result database (result DB) 12, an arithmetic processing unit 13, and an output device 14.

  The input device 11 is an input interface to which various measurement results and performance information regarding the refining facility 2 are input. The input device 11 includes a keyboard, a mouse, a pointing device, a data receiving device, and a graphical user interface (GUI). The input device 11 receives result data, parameter setting values, and the like from the outside, writes the information in the result DB 12, and transmits the information to the arithmetic processing unit 13. The input device 11 receives the measurement results of the temperature and the component concentration of at least one of the molten metal 101 before, during, and after the processing in the refining facility 2. The measurement results of the temperature and the component concentration of the molten metal 101 are input to the input device 11 by, for example, manual input by an operator or input from a recording medium. In addition, the input device 11 receives result information from the control terminal 10. The performance information includes information on the flow rate of the exhaust gas and the concentration of the components of the exhaust gas measured by the exhaust gas detection unit 105, information on the acid supply amount and the acid supply rate, information on the flow rate of the stirring gas, and the raw materials (main raw materials and auxiliary raw materials). The information includes information on the amount to be charged, temperature information of the molten metal 101, and the like.

  The arithmetic processing unit 13 is an arithmetic processing device such as a CPU, and controls the operation of the entire initial component density correction device 1. Here, the content of the arithmetic processing by the arithmetic processing unit 13 will be described. FIG. 2 is a block diagram for explaining the contents of the arithmetic processing by the arithmetic processing unit 13. As shown in FIG. 2, the arithmetic processing unit 13 includes a past blowing correction calculation unit 15 that performs a measurement value correction calculation of the charge after blowing, and a next blowing correction that corrects the initial concentration measurement value of the next charge. And a calculation unit 16.

  The past blasting correction calculation unit 15 determines when the blowing process of one charge is completed or at the end of the blowing process, the acid supply amount information, the exhaust gas information, the input auxiliary raw material information, the molten metal component before and after the processing. When the measurement result of the concentration and the FeO concentration in the slag is stored in the result DB 12, the correction parameters of the initial component concentration and the exhaust gas information are calculated so that the component balance is satisfied, and the results are stored in the result DB 12. To save.

  On the other hand, the next-time blowing correction calculation unit 16 is started before the next charging process, and performs information on the initial molten metal (concentration of each component, temperature, whether or not a preliminary process has been performed), and past blowing correction. The correction parameter information of the past charge calculated by the calculation unit 15 is read from the performance DB 12, and the component correction of the initial molten metal of the next charge is performed. The corrected initial molten metal information is transmitted to the result DB 12 and the control terminal 10, and is used for calculation of the oxygen amount of the next charge, calculation of the auxiliary material, and estimation of the internal state in real time (concentration of the components in the molten metal, temperature of the molten metal).

  FIG. 3 is a flowchart illustrating a flow of a process performed by the past blowing correction calculator 15. Next, the processing executed by the past blowing correction calculator 15 will be described with reference to the flowchart shown in FIG. In the present embodiment, a case where the present invention is applied to estimation calculation of the carbon concentration in a molten metal will be described.

  The past smelting correction calculation unit 15 receives from the control terminal 10 a signal indicating that the smelting of the charge has been completed, and starts the processing. First, in step S1, the past blowing correction calculation unit 15 confirms whether or not the reception of the information on the molten metal 101 and the slag 103 in the latest charge has been completed. That is, the past blowing correction calculator 15 calculates the molten metal component before blowing (initial), the molten metal component after blowing (C, Si, Mn, P, dissolved oxygen amount, etc.), and the slag weight in the charged after blowing. , And whether the concentration of the slag component (FeO) is stored in the performance DB 12. If the data is not stored (No in step S1), the past blowing correction calculation unit 15 periodically checks the actual DB stored data until the storage is confirmed. If the storage is confirmed (Yes in step S1), the past blowing correction calculation unit 15 collects the target charge data (including the melt component concentration information before blowing) from the performance DB 12, and proceeds to step S2.

  In step S2, the past blowing correction calculation part 15 confirms whether the reception of the information on the exhaust gas in the latest charge is completed. That is, the past blowing correction calculator 15 confirms whether or not all the exhaust gas measurement information (time-series information of the flow rate and the component concentration) of the charge that has finished blowing is stored in the performance DB 12. If it is not stored (No in step S2), the past blowing correction calculator 15 periodically checks the actual DB stored data until the storage is confirmed. If the storage is confirmed (Yes in step S2), the past blowing correction calculator 15 collects the data from the performance DB 12, and proceeds to step S3.

  In step S3, the past blowing correction calculation part 15 confirms whether the reception of the operation information in the latest charge is completed. That is, the past blowing correction calculator 15 confirms whether or not the operation information (upper blowing oxygen amount, bottom blowing gas amount, auxiliary material input amount, etc.) of the charge after blowing has been stored in the performance DB 12. If it is not stored (No in step S3), the past blowing correction calculator 15 repeats the check periodically until the storage is confirmed. If the storage is confirmed (Yes in step S3), the past blowing correction calculator 15 collects data from the performance DB 12, and proceeds to step S4.

  Here, data extracted from the performance DB 12 by the past blowing correction calculator 15 in steps S1 to S3 will be described below.

[Molten metal / slag component analysis information (step S1)]
[A1] Initial melt in C concentration _{(unit:%): x} ^{C s}
[A2] Si concentration in initial molten metal (unit:%): x _Si ^s
[A3] Mn concentration in initial molten metal (unit:%): x _Mn ^s
[A4] initial molten metal in the P concentration _{(unit:%): x} ^{P s}
[A5] blowing after the melt in C concentration _{(unit:%): x} ^{C e}
[A6] Si concentration in molten metal after blowing (unit:%): x _Si ^e
[A7] blowing after the melt in the Mn concentration _{(unit:%): x Mn} ^e
[A8] blowing after the melt in P concentration _{(unit:%): x} ^{P e}
[A9] FeO weight ratio in slag after blowing (unit:%): x _FeO ^e
[A10] Slag weight after blowing (unit: ton): w _slag
[A11] Initial molten metal weight (unit: ton): w _pig

[Exhaust gas information (step S2)]
Exhaust gas flow rate information and analysis information are collected at regular intervals. In the present embodiment, for simplicity, it is assumed that the flow rate information and the analysis information of the exhaust gas are collected in one [sec] cycle. The flow rate information and the analysis information of the exhaust gas include, for example, those shown in [B1] to [B4] below. In the following [B1] to [B4], the collection time of each piece of information is represented by t. Further, in the present embodiment, only CO, CO ₂ , and O ₂ can be measured as components in the exhaust gas. Of course, the present invention is applicable even when other components can be measured. is there.

[B1] Exhaust gas flow rate (unit: Nm ³ / Hr): V _t ^off
[B2] exhaust gas analyzing CO concentration _(unit:%): ^{X t CO}
[B3] Exhaust gas analysis CO ₂ concentration (unit:%): X _t ^{CO 2}
[B4] exhaust gas analyzing _{O 2} concentration _(unit:%): ^{X t O2}

[Operation Information (Step S3)]
[C1] above吹酸iodine flow rate _{^{(unit: Nm 3 / Hr): V}} t O-in
[C2] Soko吹gas flow rate _{^{(unit: Nm 3 / Hr): V}} t s
[C3] Integrated value of input weight of auxiliary material (unit: kg): ω _t ⁱ

Here, the subscript i of [C3] indicates the brand of the auxiliary material. The following parameters [C31] to [C33] are set for the components contained in the auxiliary material of brand i. Note that ρ _i ^O in the following [C32] means the proportion of oxygen weight that can contribute to the oxidation of C, Si, Mn, and P in the molten metal.

[Ingredients contained in the auxiliary material of brand i]
[C31] Carbon weight ratio (unit:%) in auxiliary material of brand i: ρ _i ^C
[C32] Oxygen weight ratio (unit:%) in auxiliary material of brand i: ρ _i ^O
[C33] Weight ratio (unit:%) of the slag contribution in the auxiliary material of brand i: ρ _i ^slag

After collecting information from the performance DB 12 in steps S1 to S3, the past blowing correction calculator 15 calculates values necessary for correction calculation in step S4. The values and the calculation method are shown in the following equations (1) to (11). Incidentally, t _s represents the blowing start time, t _e represents the time taken (sampling) the melt 101 by blowing terminated.

-Reduction of C contained in hot metal (unit: ton): r _C ^Pig

・ Amount of sub-material input C (unit: ton): w _C ^a

・ C content in exhaust gas (unit: ton): r _c ^OG

• Total above吹酸elementary charge ^(unit: Nm ^{3): V O}

· Katasan amount ^(unit: Nm ^{3): w O}

・ Amount of primary combustion oxygen in exhaust gas (unit: Nm ³ ): _VO-pri ^OG

・ Amount of secondary combustion oxygen in exhaust gas (unit: Nm ³ ): VO _-sec ^OG

・ Amount of unburned oxygen in exhaust gas (unit: Nm ³ ): VO ₂ ^OG

-Unanalyzed exhaust gas amount (unit: Nm ³ ): V _rem ^OG

・ Bottom blowing gas amount (unit: Nm ³ ): V ^stir

・ Amount of metal oxidation in molten metal (unit: Nm ³ ): w ^O-metal

The terms of the amount of metal oxidation in the molten metal are the amount of oxygen used for oxidation of Si, the amount of oxidation used for oxidation of Mn, the amount of oxygen used for oxidation of P, and the amount of oxygen used for oxidation of Fe. ^Where k ^Si , km ⁿ , and k ^P are conversion factors (unit: Nm ³ / ton) for calculating the amount of oxygen [Nm ³ ] necessary to oxidize each element 1 [ton]. is there. The fourth term, 72, is the formula weight of FeO, and ρ _i ^Si , ρ _i ^Mn , and ρ _i ^P are the weight [ton] of each element dissolved in the molten metal 101 when 1 [ton] of the auxiliary material of the brand i is used. ] Is calculated (unit:%).

Next, the correction parameters in step S4 will be described. In the present embodiment, it is assumed that a large error is included in the exhaust gas flow rate, the CO concentration in the exhaust gas, the CO ₂ concentration, and the C concentration in the initial molten metal, and the correction parameter is α ₁ (a parameter of the exhaust gas flow rate). , Α ₂ (parameters of CO and CO ₂ concentration in exhaust gas), and β (parameter of initial molten metal concentration). Incidentally, the error of the CO concentration and the CO ₂ concentration assuming the same level, and using the correction parameters of the same alpha _2. These correction parameters α ₁ , α ₂ , and β correct original measurement values in the following forms [D1] to [D4].

[D1] Exhaust gas flow rate correction value (unit: Nm ³ / h): α ₁ V _t ^off
[D2] Correction value of CO concentration in exhaust gas (unit:%): α _{2 Xt} ^CO
[D3] Correction value of CO ₂ concentration in exhaust gas (unit:%): α _{2 Xt} ^{CO 2}
[D4] Initial melt C density correction value _{(unit%): x} ^{c s} + β

In step S4, the past blowing correction calculation unit 15 performs a minimization calculation of an evaluation function J represented by the following equation (12) using the correction parameters α ₁ , α ₂ , and β as variables.

The variables of the evaluation function J include the secondary combustion amount γ (unit: Nm ³ ) in addition to the correction parameters α ₁ , α ₂ , and β. This secondary combustion amount γ means the amount of oxygen used in the secondary combustion of carbon in the top-blown oxygen.

The numerator of the first term of the evaluation function J is the square of the mass balance difference of carbon, and when this value becomes 0, it means that the mass balance is completely balanced. The numerator of the second term of the evaluation function J is the square of the mass balance difference of oxygen used for the primary combustion of carbon (2C + O ₂ → 2CO). The numerator of the third term of the evaluation function J is the square of the mass balance difference of oxygen used for carbon secondary combustion (2CO + O ₂ → 2CO ₂ ).

In the third term of the evaluation function J, the secondary combustion amount γ means the amount of oxygen used in the secondary combustion of carbon in the upper-blown oxygen, and is 21/78 × (α ₁ V _rem ^OG + 2α ₁ (1 -Α ₂ ) V _O-pri ^OG -V ^stir ) means the amount of oxygen used for the secondary combustion of carbon in the air flowing into the process, and α ₁ α ₂ V _O-sec ^OG is contained in the exhaust gas. It means the amount of oxygen required for secondary combustion (2CO + O ₂ → 2CO ₂ ) to generate CO ₂ .

In the third term of the evaluation function J, min could not be component analysis in the exhaust gas ( _{"100-α 2 X CO -α 2} X CO2 -X O2 "% of the exhaust gas) is blown nitrogen and bottom of the inlet air It is assumed that the total value is the sum of the gas amount (using an inert gas Ar or the like) V ^stir and that the oxygen of the inflow air all contributes to the secondary combustion. The ratio between the amount of oxygen in the atmosphere and the amount of nitrogen for calculating the amount of oxygen in the inflowing atmosphere is 21:78.

The fourth to sixth terms of the evaluation function J are terms for preventing the correction parameters α ₁ , α ₂ , and β from taking extreme values, and α ₁ ′, α ₂ ′, and β ′ are respectively These are standard values (fixed parameters) of α ₁ , α ₂ , and β. For these standard values α ₁ ′, α ₂ ′, and β ′, for example, the average values of the calculation results of the latest charges α ₁ , α ₂ , and β are substituted. The parameter σ _{* in} the denominator of each term (however, “*” is C, O-pri, O-sec, α1 _, α2 _, or β) determines which term error is important. The correction parameters α ₁ , α ₂ , β and the secondary combustion amount γ are calculated so that the error is reduced as the parameter σ _* becomes smaller. Is done. Since the secondary combustion amount γ does not take a negative value, it is necessary to satisfy the constraint condition of the following equation (13).

  Under the constraints of the above equation (13), in order to minimize the evaluation function J of the above equation (12), a non-linear optimization method (for example, reference literature (Hiroshi Konno, Hiroshi Yamashita, "Nonlinear Programming", Refer to JPN)).

In general minimization problems, it is difficult to calculate an exact (global) optimal solution if the conditions are not met. In such a case, a local optimal solution (evaluation within the search range) The solution that minimizes the function) is often the optimal solution. When it is difficult to obtain a global optimal solution also in the present invention, the correction parameters α _1, α ₂ , β and the secondary combustion amount γ that minimize the evaluation value in a local range may be used. The above references describe methods for calculating various local optimal solutions.

Finally, in step S5, the past blowing correction calculator 15 transmits and stores the correction parameters α ₁ , α ₂ , and β obtained in step S4 to the performance DB 12.

  FIG. 4 is a flowchart illustrating a flow of a process executed by the next blowing correction calculator 16. Next, the processing executed by the next blowing correction calculator 16 will be described with reference to the flowchart shown in FIG.

  The next-time blowing correction calculation unit 16 corrects the initial component concentration (hot metal component) in the molten metal for the next charge before the processing of the next charge. The calculation starts when the molten metal information of the next charge and the processing-related information are received. First, in step S11, the next blowing correction calculator 16 confirms whether or not the molten metal 101 and the processing-related information in the next charging have been received. That is, the next-time blowing correction calculation unit 16 confirms whether the initial molten metal information (initial molten metal temperature, initial molten metal component concentration) and the processing-related information of the next charged are stored in the result DB 12 after the previous charging is completed. If the data is not stored (No in step S11), the next blowing correction calculation unit 16 periodically repeats the check of the actual DB stored data until the storage is confirmed. If the storage is confirmed (Yes in step S11), the next blowing correction calculator 16 collects the initial molten metal information and process-related information of the next charge from the performance DB 12, and proceeds to step S12. The processing-related information includes, for example, the following information [E1] to [E3].

[Processing related information]
[E1] Information on processing before converter blowing (information on the presence or absence of preprocessing and equipment that performed preprocessing)
[E2] Information on the furnace body (information on the time when refractory was replaced)
[E3] Information on initial melt component measurement (measurement equipment, scheduled time from start of component measurement to start of processing)

  The “at the start of component measurement” in the above [E3] means that, for example, when a spark discharge emission spectroscopy called so-called Cantback is used for component measurement of the initial molten metal, a sample for analysis is collected from the molten metal. (Sampling). The “at the start of processing” is, for example, a point in time when high-pressure oxygen ejection from the lance 102 to the molten metal 101 is started.

  In step S <b> 12, the next blowing correction calculation unit 16 extracts information on the past charge that satisfies the condition from the result DB 12. The information on the past charge extracted from the performance DB 12 is the melt information of the past charge, the processing-related information, the calculation result (correction parameter) of the past blowing correction calculator 15, and the like.

In step S13, the next blowing correction calculator 16 calculates a weight coefficient for each operating condition of each past charge. That is, the next-time blowing correction calculation unit 16 first determines the next-time charge and each past-related information for each item of the melt information of the past charge, and the operation information such as the blowing method for each charge, the grade of the steel material, and various operation amounts. The difference from the charge information is calculated, and the weighted square sum square root is calculated. Next, the next-time blowing correction calculation unit 16 calculates a weighting coefficient w _k = f (d _k ) as a weighting parameter for the value d _k of the weighted square root sum of squares relating to the past charge k. Note that “f” is a monotonically decreasing function, and the weight coefficient w _k takes a large value when the next charge and the past charge k are similar (the difference between the items is close to 0).

In step S14, the next blow correction calculation unit 16, using the weight coefficient w _k calculated in step S13, it acquires the regression calculating a correction amount of the initial carbon concentration. That is, the next-time blowing correction calculation unit 16 obtains a regression equation by performing a regression calculation with the weighting coefficient w _k calculated in step S13, and then uses the regression equation to calculate an initial carbon concentration correction amount for the next charge. Is estimated.

Following the equation (14), the initial component concentration measurements in the melt at least the next charge is included in the explanatory variables, in particular the explanatory variables in the initial melt C concentration x _{c s} ^(k), in the initial melt The regression equation is shown in the case where the three variables are the Si concentration x _Si ^s (k) and the initial molten metal temperature T ^s (k). Here, β _k is the initial carbon concentration correction value of the past charge k.

In the regression calculation, a ₀ , a ₁ , a ₂ , and a ₃ that minimize the above equation (14) are derived. This regression calculation can be easily performed by an inverse matrix calculation.

Using the regression parameters a ₀ , a ₁ , a ₂ , and a ₃ obtained by the regression calculation, the correction amount of the initial molten carbon concentration in the next charge is calculated. Initial melt in the carbon concentration of the next charge, initial melt in the Si concentration, and, respectively, the initial molten metal ^{_{temperature, x C s (next),}} x Si s (next), When T s (next), the correction amount beta _next is It is obtained by calculation of the following equation (15).

In step S15, the next blowing correction calculator 16 calculates an initial carbon concentration correction value based on the correction amount obtained in step S14, and transmits the same to the control terminal 10 and the result DB 12. Then, the next blowing correction calculator 16 corrects the initial molten carbon concentration from the correction amount β _next obtained in step S14. The correction equation used in this case is shown in the following equation (16).

Initial melt in the carbon concentration after correction _x ^{C s'} (next) is transmitted to the control terminal 10 and the actual DB 12. Based on the control terminal of the corrected in 10 initial melt in the carbon concentration x _C ^s' (next), it calculates the blowing amount of oxygen and the sub raw material input required. Further, as the initial carbon concentration in calculating the melt in the carbon concentration changes in blowing the balance calculation based on the exhaust gas information, the initial molten metal in the carbon concentration after correction x _C ^s' (next) is used. The accuracy of each calculation is improved by correcting the carbon concentration in the initial molten metal, and it is possible to suppress an excessive amount of acid supply and an amount of input of auxiliary materials, thereby greatly reducing production costs.

[Example]
In the present invention example in which the initial carbon concentration correction was performed and the comparative example in which the initial carbon concentration correction was not performed, it is necessary to use the initial carbon concentration to reach the target carbon concentration at the time of S / L from the start of blowing. The oxygen insufflation was calculated and compared to the actual oxygen estimates. The model used in the oxygen amount calculation is called a static oxygen model, and the upper blowing oxygen required to bring the concentrations of each component (C, Si, P, Mn) in the molten metal from the initial concentration to the respective target concentrations. The amounts are calculated based on a physical model and summed. In the model, it is assumed that each component is oxidized by the injected oxygen and then removed by moving from the molten metal 101 into exhaust gas or slag.

Figure 5 is a graph showing the amount of oxygen Determination of middle S / L at the target carbon concentration x _C ^*. FIG. 6 is a diagram showing the relationship between the blowing time and the C concentration in the molten metal by the carbon balance calculation. The line graphs LC1 in FIGS. 5 and 6 are obtained by multiplying the amount of C contained in the exhaust gas and out of the furnace by a predetermined coefficient to obtain the molten metal at the time of the blowing time T2 which is the S / L execution time on the way. medium C concentration shows a molten metal in a C concentration adjusted to match the way S / L at the carbon concentration measuring value x _C ^m. The line graph LC2 in FIG. 6 shows the C concentration in the molten metal obtained by subtracting the amount of C contained in the exhaust gas and out of the furnace.

As the actual oxygen amount estimation value, as shown in a line graph LC1 in FIG. 5, oxygen blown by the time of the blowing time T1 when the C concentration in the molten metal reached the target S / L-time target carbon concentration x _C ^* as shown in the line graph LC1. The amount was used. Note that the line graph LC1 is obtained by using the initial carbon concentration actual value (with or without correction), the auxiliary raw material input actual value, and the exhaust gas information (flow rate, concentration) actual value every moment. By calculating the carbon balance, the C concentration in the molten metal is calculated every moment. However, in this calculation, the line graph LC2 in FIG. 6 is obtained by using the calculation result as it is. On the other hand, in this embodiment, so that the molten metal in the C concentration at the time of blowing time T2 in the middle S / L implementation time, consistent with the way S / L at the carbon concentration measuring value x _C ^m, momentary When calculating the C concentration in the molten metal, a predetermined coefficient is multiplied by the amount of C coming out of the exhaust gas. Thereby, a corrected line graph LC1 is obtained from the line graph LC2 as shown in FIG.

  FIG. 7 is a graph showing the conversion value of the standard deviation for 500 charges for the difference between the calculated oxygen amount and the actual oxygen amount in the present invention example and the comparative example. The vertical axis of FIG. 7 is a conversion value obtained by converting the standard deviation of the difference between the calculated oxygen amount and the actual oxygen amount so that the calculation result of the comparative example becomes 100. As shown in FIG. 7, in the example of the present invention, the calculation error was reduced to half or less by correcting the initial carbon concentration compared with the comparative example in which the initial carbon concentration was not corrected. This shows that the technique for correcting the initial carbon concentration according to the present invention contributes to improving the blowing accuracy and reducing the cost.

Reference Signs List 1 Initial component concentration correction device 2 Refining equipment 10 Control terminal 11 Input device 12 Result database (Result DB)
13 arithmetic processing unit 14 output device 15 past blowing correction calculation unit 16 next blowing correction calculation unit 20 display device (CRT)
Reference Signs List 100 converter 101 molten metal 102 lance 103 slag 104 duct 105 exhaust gas detector 106 vent 107 flow meter

Claims (6)

As the input information, the measurement result of the component concentration of the molten metal during or after the treatment in the refining facility, the flow rate of the exhaust gas discharged from the refining facility and the measurement result of the component concentration in the exhaust gas, An input device for inputting information about the amount of oxygen to be blown, information about the weight and component concentration of the molten metal before the processing, and information about the weight of the auxiliary material input during the processing;
Based on the input information and the calculation result of the balance of carbon and oxygen, in the past charge, the measured value of the flow rate of the exhaust gas discharged from the refining facility, the measured value of the component concentration in the exhaust gas, and A past blowing correction calculation unit that calculates a correction parameter for correcting the measured value of the initial component concentration of,
Information storage means for storing the input information, the correction parameter, and operation information of past charges,
Initial values for correcting the initial component concentration in the melt at the next charge based on the input information, the operation information, the correction parameter, the measured value of the initial component concentration in the melt at the next charge, and the operation information of the next charge. A component concentration correction value, and a next blowing correction calculation unit for correcting the initial component concentration in the molten metal in the next charge using the initial component concentration correction value,
An initial component concentration correction device, comprising:   The previous blowing correction calculator is calculated from the component analysis value of the molten metal and the amount of carbon contained in the added auxiliary material, the carbon reduction in the molten metal during the specified period during blowing and the exhaust gas during the specified period during blowing. The correction parameter for minimizing an evaluation function based on a difference from a medium carbon amount and an evaluation function based on a balance regarding an oxygen amount used for carbon combustion, wherein the correction parameter is calculated. An apparatus for correcting the initial component concentration as described in the above. The next blowing correction calculation unit calculates the initial component concentration correction value using a regression equation that determines parameters based on past charges,
3. The initial component concentration correction device according to claim 1, wherein the explanatory variable of the regression equation includes at least a measured value of an initial component concentration in the molten metal in the next charge. As the input information, the measurement result of the component concentration of the molten metal during or after the treatment in the refining facility, the flow rate of the exhaust gas discharged from the refining facility and the measurement result of the component concentration in the exhaust gas, Information about the amount of oxygen to be blown, information about the weight and component concentration of the molten metal before the processing, and information about the weight of the auxiliary material input during the processing,
Based on the input information and the calculation result of the balance of carbon and oxygen, in the past charge, the measured value of the flow rate of the exhaust gas discharged from the refining facility, the measured value of the component concentration in the exhaust gas, and Calculating a correction parameter for correcting the measured value of the initial component concentration of
Saving the input information, the correction parameter, and the operation information of the past charge;
Initial values for correcting the initial component concentration in the melt at the next charge based on the input information, the operation information, the correction parameter, the measured value of the initial component concentration in the melt at the next charge, and the operation information of the next charge. Calculating a component concentration correction value, and correcting the initial component concentration in the molten metal in the next charge using the initial component concentration correction value;
A method for correcting the initial component concentration.   5. A refining process state comprising a step of estimating a transition of a component concentration in the molten metal based on the initial component concentration in the molten metal at the next charge corrected by the initial component concentration correcting method according to claim 4. Estimation method.   Adjusting a component concentration in the molten metal within a desired range based on a change in the component concentration in the molten metal in the next charge, estimated using the refining process state estimation method according to claim 5. Characteristic converter operation method.

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