JP6579136B2 - Refining process state estimation device, refining process state estimation method, and molten metal manufacturing method - Google Patents

Description

  The present invention relates to a refining process state estimation device, a refining process state estimation method, and a molten metal manufacturing method for estimating component concentrations in molten metal and slag in a steel industry refining facility.

  In a steelworks, after melting 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 facilities depending on the pretreatment facilities, converters, and secondary refining facilities and processing purposes. For example, in a converter that is a typical refining equipment, oxygen is blown into the furnace to remove impurities in the molten metal and raise the temperature, and the component concentration and temperature of the molten metal are within the specified range. Control is performed as follows. However, since the oxidation reaction in the molten metal is intense and the molten metal becomes hot, it is difficult to measure the component concentration and temperature in the molten metal every moment. For this reason, in actual operation, the molten metal being blown is sampled, and blowing control (determining the required amount of oxygen sent and coolant input) is determined based on the information and reaction model obtained by sampling. Calculation is performed.

  If information on the component concentration and temperature of the molten metal can be obtained continuously, the processing accuracy can be improved. Currently, 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 manipulated variable. It is possible to estimate the amount of carbon discharged outside the furnace using information on the exhaust gas, and the carbon component concentration in the molten metal can be calculated based on the amount of discharged carbon from the material balance. However, in general, information measured for exhaust gas has a large error. For example, the flow rate value of exhaust gas is generally 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 exhaust gas frequently fluctuate greatly, the above method tends to increase the error. In order to cope with such a problem, Patent Document 1 calculates a coefficient for correcting the measurement value based on the past results regarding the exhaust gas flow rate of the steel refining process, and further calculates the coefficient based on the molten metal analysis result during the 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 decrease in the molten metal. In many cases, the amount of carbon is corrected by correcting the exhaust gas flow rate. Although it is possible to balance the balance, on the other hand, the balance of oxygen amount often does not match. In this case, it becomes difficult to accurately estimate and calculate the amount of oxygen in the furnace using the corrected exhaust gas flow rate value. This may be due to errors in not only the exhaust gas flow rate but also the component concentration in the exhaust gas. By correcting the exhaust gas flow rate and the component concentration in the exhaust gas simultaneously, It can be expected that the accuracy of quantity estimation calculation can be improved.

  The objective of this invention is providing the refining process state estimation apparatus and refining process state estimation method which can improve the estimation precision of the component density | concentration in a molten metal and slag. Another object of the present invention is to provide a method for producing a molten metal capable of accurately adjusting the component concentration in the molten metal within a desired range.

  The refining process state estimation device according to the present invention includes a measurement result of a component concentration of a molten metal being processed in a refining facility, a flow rate of exhaust gas discharged from the refining facility and a measurement result of a component concentration in the exhaust gas, An input device for inputting information on the amount of oxygen blown into the furnace, information on the weight and component concentration of the molten metal before processing, and information on the weight of the auxiliary raw material charged during processing, and the molten metal before or during processing The flow rate of the exhaust gas discharged from the refining equipment based on the measurement result of the component concentration, the flow rate of the exhaust gas discharged from the refining equipment, the measurement result of the component concentration in the exhaust gas, and the balance calculation result of carbon and oxygen And a correction calculation unit for calculating a correction parameter for correcting the measured value of the component concentration in the exhaust gas, the correction parameter, the flow rate of the exhaust gas, and the component concentration in the exhaust gas Based on the measurement results, the amount of oxygen blown in, the weight and concentration of the molten metal before the treatment, and the weight of the auxiliary raw material charged during the treatment, the material balance is calculated for each component in the molten metal and the slag in the molten metal. And a substance balance calculation unit for estimating the concentration of the components therein.

  In the refining process state estimation apparatus according to the present invention, in the above invention, the correction calculation unit is configured to reduce the carbon content in the molten metal during a specified period during the treatment, which is calculated from the component analysis value of the molten metal and the amount of carbon contained in the added auxiliary material. A correction parameter that minimizes an evaluation function based on a difference between the amount of carbon and the amount of carbon in exhaust gas, and an evaluation function based on a balance about the amount of oxygen used for carbon combustion is calculated.

  In the refining process state estimation device according to the present invention, in the above-mentioned invention, the evaluation function is a balance with respect to a square value of a difference between a carbon reduction amount in the molten metal and a carbon amount in the exhaust gas, and an oxygen amount used for carbon combustion. It is a weighted sum including a value based on it as a term.

  The refining process state estimation method according to the present invention includes a measurement result of a component concentration of a molten metal being processed in a refining facility, a flow rate of exhaust gas discharged from the refining facility, a measurement result of a component concentration in the exhaust gas, An input step for inputting information on the amount of oxygen blown into the furnace, information on the weight and component concentration of the molten metal before processing, and information on the weight of the auxiliary raw material charged during processing, and the molten metal before or during processing Based on the measurement result of the component concentration, the flow rate of the exhaust gas discharged from the refining facility, the measurement result of the component concentration in the exhaust gas, and the balance calculation result of carbon and oxygen, the flow rate of the exhaust gas discharged from the refining facility and A correction calculation step for calculating a correction parameter for correcting the measured value of the component concentration in the exhaust gas, the correction parameter, the flow rate of the exhaust gas, and the composition in the exhaust gas. Based on the measurement result of concentration, the amount of oxygen blown in, the weight and component concentration of the molten metal before treatment, and the weight of the auxiliary material charged during the treatment, by calculating the material balance for each component in the molten metal, And a substance balance calculation step for estimating a component concentration in the slag.

  The method for producing a molten metal according to the present invention includes a step of adjusting the component concentration in the molten metal within a desired range based on the component concentration in the molten metal estimated using the refining process state estimating method according to the present invention. It is characterized by.

  According to the refining process state estimation device and the refining process state estimation method according to the present invention, the correction parameters for the exhaust gas flow rate and the component concentration are calculated based on the carbon amount balance and the oxygen amount balance of the refining equipment, and the calculated correction parameters Since the concentration of the component in the molten metal and the slag is estimated by performing the material balance calculation using, the estimation accuracy of the component concentration in the molten metal and the slag can be improved. Further, according to the molten metal production method according to the present invention, the component concentration of the molten metal is adjusted within a desired range based on the component concentration in the molten metal estimated by the refining process state estimation method according to the present invention. It is possible to accurately adjust the concentration of the components in the desired range.

FIG. 1 is a schematic diagram showing a configuration of a refining process state estimation apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram for explaining the contents of the arithmetic processing by the arithmetic processing unit shown in FIG. FIG. 3 is a flowchart showing the flow of a refining process state estimation process according to an embodiment of the present invention.

  Hereinafter, the configuration and operation of a refining process state apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

[Configuration of refining process state estimation device]
First, with reference to FIGS. 1 and 2, the configuration of a refining process state estimation apparatus according to an embodiment of the present invention will be described.

  FIG. 1 is a schematic diagram showing a configuration of a refining process state estimation apparatus according to an embodiment of the present invention. As shown in FIG. 1, the refining process state estimation apparatus 1 which is one Embodiment of this invention is an apparatus which estimates the component density | concentration of the molten metal 101 currently processed with the refining equipment 2 of the steel industry. Here, the refining equipment 2 includes a converter 100, a lance 102, and a duct 104. A lance 102 is disposed 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. Impurities in the molten metal 101 are oxidized by this high-pressure oxygen and taken into the slag 103 (blowing process). At the upper part of the converter 100, a duct 104 for introducing exhaust gas smoke is installed.

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

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

  A blowing control system to which the refining process state estimation device 1 and the refining process state estimation method are applied includes a control terminal 10, a refining process state estimation device 1, and a display device 20 as main components. The control terminal 10 is configured by an information processing device such as a personal computer or a workstation, and controls the amount of acid supplied, the rate of acid supply, and the flow rate of the stirring gas so that the component concentration of the molten metal 101 falls within a desired range. Collect data on the actual values of the amount of acid delivered, the rate of acid delivery, and the flow rate of stirring gas.

  The refining process state estimation device 1 is configured by an information processing device such as a personal computer or a workstation. The refining process state estimation device 1 includes an input device 11, a performance database (result DB) 12, an arithmetic processing unit 13, and an output device 14.

  The input device 11 is an input interface through which various measurement results and performance information related to the refining facility 2 are input. The input device 11 includes a keyboard, a mouse, a pointing device, a data receiving device, a graphical user interface (GUI), and the like. The input device 11 receives performance data, parameter setting values, and the like from the outside, and writes the information to the performance DB 12 and transmits it to the arithmetic processing unit 13. The input device 11 receives the measurement result of the temperature and component concentration of at least one of the molten metal 101 before and during the treatment in the refining equipment 2. Measurement results regarding the temperature and component concentration of the molten metal 101 are input to the input device 11 by, for example, manual input by an operator or reading input from a recording medium. The record information is input to the input device 11 from the control terminal 10. The results information includes information on the flow rate of exhaust gas and the component concentration of exhaust gas measured by the exhaust gas detection unit 105, information on the amount of acid sent and the rate of acid feed, information on the stirring gas flow rate, and the input amount of raw materials (main raw materials and auxiliary raw materials) Information, 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 refining process state estimation device 1. The arithmetic processing unit 13 functions as a correction calculation unit 15 and a substance balance calculation unit 16. The correction calculation unit 15 and the substance balance calculation unit 16 are realized, for example, when the arithmetic processing unit 13 executes a computer program. The arithmetic processing unit 13 functions as the correction calculation unit 15 by executing the computer program for the correction calculation unit 15, and functions as the substance balance calculation unit 16 by executing the computer program for the substance balance calculation unit 16. The arithmetic processing unit 13 may include a dedicated arithmetic device or arithmetic circuit that functions as the correction calculation unit 15 or the substance balance calculation unit 16.

  Here, the contents of the arithmetic processing by the arithmetic processing unit 13 will be described with reference to FIG. 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 correction calculation unit 15 stores the information on the amount of acid sent from the input device 11, the exhaust gas information, the input auxiliary material information, and the measurement result of the carbon concentration in the molten metal and the result DB 12. Are used to calculate the correction parameter of the exhaust gas information. The substance balance calculation unit 16 calculates the substance balance of the components based on the correction parameter, the measurement result of the exhaust gas information, and the amount of injected oxygen, and estimates the component concentration in the molten metal 101 and the slag 103. The substance balance calculation is a calculation for estimating the component amount and the component concentration of each component in the molten metal 101 and the slag 103 based on the input amount of each component into the molten metal 101 and the discharged amount of each component from the molten metal 101. The input amount of each component is calculated from the input amounts of the main raw material and the auxiliary raw material to the converter 100. Among the emission amounts of each component, the carbon emission amount is calculated from the flow rate of the exhaust gas and the carbon concentration in the exhaust gas.

  The output device 14 outputs the estimation result by the substance balance calculation unit 16. The output device 14 is connected to the control terminal 10 and the display device 20, and outputs an estimation result to the control terminal 10 and the display device 20. The control terminal 10 adjusts the operation amount such as the acid supply amount, the acid supply speed, the stirring gas flow rate and the like based on the estimation result sent from the output device 14, thereby determining the component concentration in the molten metal 101 and the temperature of the molten metal 101. Adjust within the range. The display device (CRT) 20 displays the transition of the estimated value sent from the output device 14 as a chart on a display unit such as a screen.

  The refining process state estimation device 1 having such a configuration estimates the component concentration in the molten metal and slag with high accuracy by executing the following refining process state estimation process. Hereinafter, the operation of the refining process state estimation apparatus 1 when executing the refining process state estimation process will be described with reference to the flowchart shown in FIG. Hereinafter, a case where the present invention is applied to the estimation calculation of the carbon concentration in the molten metal will be described.

[Refining process state estimation processing]
FIG. 3 is a flowchart showing the flow of a refining process state estimation process according to an embodiment of the present invention. The flowchart shown in FIG. 3 starts at the timing when the blowing process is started, and the refining process state estimation process proceeds to the process of step S1.

  In the process of step S <b> 1, the arithmetic processing unit 13 acquires the measurement / analysis value of the molten metal 101. The arithmetic processing unit 13 acquires a measurement / analysis result obtained by temperature measurement and component analysis on the sample of the molten metal 101. In general, the analysis process of the molten metal component often takes time. Therefore, for the carbon concentration C, an estimated value based on the solidification temperature of the molten metal 101 and the oxygen concentration for the electromotive force of the molten metal 101 may be used as an alternative value. If a new result is input to the input device 11 as a measured / analyzed value of the molten metal 101, the arithmetic processing unit 13 sets the newly acquired measured / analyzed value to be used for estimating the refining process state. Update. Thereby, the process of step S1 is completed and the refining process state estimation process proceeds to the process of step S2.

In the process of step S <b> 2, the arithmetic processing unit 13 acquires operation amount information, exhaust gas measurement / analysis information (exhaust gas information), and auxiliary material input amount information from the control terminal 10. In normal converter blowing operation, the manipulated variable information and exhaust gas measurement / analysis information are collected at regular intervals. In this embodiment, for the sake of simplicity, it is assumed that exhaust gas measurement / analysis information is collected in a 1-sec cycle. Examples of the manipulated variable information and exhaust gas measurement / analysis information include the following. In the following, the collection time of each information is t. Further, only CO, CO ₂ , and O ₂ can be measured as components in the exhaust gas, but the present embodiment is applicable even when other components can be measured.

  In addition, if there is a large time delay between the collection time of the manipulated variable information and the collection time of the exhaust gas measurement / analysis information, consider the time delay (for example, collection of exhaust gas measurement / analysis information for the delay time). It is desirable to collect each information (by advancing the time). Further, the auxiliary raw material input amount information is composed of the brand of the auxiliary raw material input from the start of blowing to the current time and the cumulative input weight as shown below. Thereby, the process of step S2 is completed and the refining process state estimation process proceeds to the process of step S3.

(Operation amount information)
[A1] Top blowing oxygen flow rate (unit: Nm ³ / Hr): V _t ^O-in
[A2] Soko吹gas flow rate _{^{(unit: Nm 3 / Hr): V}} t s

(Exhaust gas measurement / analysis information)
[B1] Exhaust gas flow rate (unit: Nm ³ / Hr): V _t ^off
[B2] Exhaust gas analysis CO concentration (unit:%): X _t ^CO
[B3] exhaust gas analyzing the CO ₂ concentration ^{_(unit:%): X t CO2}
[B4] exhaust gas analyzing _{O 2} concentration _(unit:%): ^{X t O2}

(Sub-material input information)
Stock code: i
Carbon weight ratio (unit:%) in auxiliary material of brand code i: ρ _i
Accumulated input weight (unit: kg) of subsidiary material of brand code i at time t: ω _t ⁱ

In the process of step S3, the correction calculation unit 15 calculates correction parameters for the exhaust gas flow rate and the exhaust gas component concentration using the information acquired in the processes of step S1 and step S2. Specifically, it is assumed that the exhaust gas flow rate, the CO concentration in the exhaust gas, and the CO ₂ concentration in the exhaust gas contain large errors, and the correction parameters are α ₁ (correction parameter for the exhaust gas flow rate) and α ₂ (exhaust gas), respectively. Correction parameter for medium CO concentration and CO ₂ concentration in exhaust gas). Note that the same correction parameter α ₂ is used on the assumption that the error between the CO concentration in the exhaust gas and the CO ₂ concentration in the exhaust gas is approximately the same. These correction parameters correct the original measurement values in the form of products as shown below.

Exhaust gas flow rate correction value (unit: Nm ³ / Hr): α ₁ V _t ^off
CO concentration correction value in exhaust gas (unit:%): α ₂ X _t ^CO
CO ₂ concentration correction value in exhaust gas (unit:%): α ₂ X _t ^CO2

The correction calculation unit 15 calculates the correction parameters α ₁ and α ₂ based on the material balance between the two component analysis timings in the molten metal (before or during the treatment). When the timing t at which the analysis of the components in the molten metal is performed twice is time s1 and time s2 (time s1 is earlier than time s2), the mass balance relating to carbon is expressed by the following mathematical formula (1). However, if there is a time delay in the flow rate or component information of the exhaust gas, it may be replaced with a value that takes it into account.

  Here, in Equation (1), the right side is the carbon weight contained in the exhaust gas, and the left side is the carbon weight reduced in the molten metal 101. Each variable on the left side means the following.

W _s1 ^C : Carbon weight (ton) in molten metal 101 at time s1 (calculated from carbon component measurement value and molten metal weight at time s1)
W _s2 ^C : Carbon weight (ton) in molten metal 101 at time s2 (calculated from carbon component measurement and molten metal weight at time s2)
w _t ^C : carbon weight (ton) contained in the auxiliary raw materials charged at time t-1 to t (each auxiliary raw material input amounts ω _t-1 ⁱ and ω _t ^{i at} time t-1 and t) (Calculated from carbon weight ratio ρ _{i in} each auxiliary material)

In order to satisfy the mass balance of carbon, it is necessary to satisfy the equation (1), but the correction parameters α ₁ and α ₂ that satisfy this equation are generally not fixed to one. Therefore, correction parameters α ₁ and α ₂ satisfying Equation (1) are determined using the condition on the mass balance of oxygen as a constraint. The constraints (inequality) regarding the mass balance of oxygen are shown in the following mathematical formulas (2) and (3).

  The meaning of each variable used in Equations (2) and (3) is described below.

V ^{_s1, s2 O2-in:} the amount of oxygen blown into the furnace during the period from the time s1 to time s2 ^(Nm ₃₎ ^(calculated by integrating the ^{V t O-in)}
V _{s1, s2} ^O-met : the amount of oxygen (Nm ³ ) used to oxidize components (other than Fe) in the molten metal 101 from time s1 to time s2,
v _t ^O : oxygen content (Nm ³ , volume conversion) contained in various auxiliary materials introduced between time t-1 and t

The above equation (2) is an equation representing the overall oxygen balance calculation, and the first and third terms mean the amount of oxygen charged into the furnace as blown oxygen and solid oxygen, respectively. The fourth term means the amount of oxygen contained in air (hereinafter referred to as entrained air) that has entered the furnace through a gap between the converter and the skirt. In the fourth term, the concentration of CO, CO ₂ , O ₂ and the amount of bottom blowing gas (CO, CO ₂ ) measured on the assumption that “the components in the exhaust gas are composed of only CO, CO ₂ , O ₂ and N ₂ ” are measured. _{2, O 2} exclusive) to calculate the flue gas _{N 2} amount based on, _O 2, _{N 2} ratio of the atmosphere is calculating the amount of oxygen in the air entrainment assuming seventy-eight past nine p.m.. The second term is the amount of oxygen used to oxidize components in the melt other than Fe (Si, Mn, Ti, P, etc.), and this value is calculated based on the analysis results at times s1 and s2. Alternatively, it may be a value estimated using a model. The fifth term is obtained by converting the oxygen component contained in the exhaust gas into the volume of O ₂ . That is, the left side of Equation (2) means the difference between the amount of oxygen that has entered the furnace and the amount of oxygen that has gone out of the furnace (or moved into the slag), and this value is greater than zero. Need to be. Specifically, the left side can be considered as the amount of oxygen used for the oxidation of FeO.

Next, in the above formula (3), the first term means the amount of oxygen used for secondary combustion of carbon (2CO + O ₂ → 2CO ₂ ), and the second term is the amount of oxygen in the entrained air. Means. Formula (3) satisfies the condition that “all the oxygen in the entrained air is used only for secondary combustion of carbon (that is, oxygen in the entrained air is not used for primary combustion of carbon)”. When the left side becomes positive, the value on the left side means the amount of oxygen used for secondary combustion of carbon in the injected oxygen or the oxygen in the auxiliary raw material.

A method of obtaining an appropriate combination of correction parameters α ₁ and α ₂ that satisfies the inequalities of the above formulas (1) to (3) as much as possible will be described below. Since there are two variables and the equation is only one of equation (1), the following three situations can occur:

(Situation 1) There are a plurality of correction parameters α ₁ and α ₂ that satisfy the mathematical expressions (1) to (3).
(Situation 2) There are no correction parameters α ₁ and α ₂ that satisfy the mathematical expressions (1) to (3).
(Situation 3) There is one correction parameter α ₁ , α ₂ that satisfies the equations (1) to (3).

In the case of (Situation 1), it is necessary to select one combination of correction parameters α ₁ and α ₂ from a plurality of solutions. In particular, since the correction parameters α ₁ and α ₂ often take values close to the charge processed immediately before the target charge, the correction parameters α ₁ and α ₂ are selected so as not to deviate significantly from the values. In the case of (Situation 2), it is required to calculate appropriate correction parameters α ₁ and α ₂ while relaxing the condition of Equation (1) or Equation (2). In the case of (Situation 3), the obtained correction parameter may be adopted as it is. Based on the above, an optimization problem for obtaining the correction parameters α ₁ and α ₂ will be described below. In this optimization problem, correction parameters α ₁ and α ₂ that minimize the evaluation value shown in the following equation (4) are obtained.

  However, the numerator of the first term of the formula (4) is the square value of the difference between the left side and the right side of the formula (1). Specific mathematical formula (5) is shown below.

  In addition, the numerator of the second term of the formula (4) takes a value calculated by the following formula (6) when the formula (2) is satisfied and zero when the formula (2) is not satisfied. Formula (6) is the square value of the left side of Formula (2), and is a function (generally called a penalty function) that takes a large value when Formula (2) is not satisfied.

Further, the third and fourth terms of the above formula (4) are terms for preventing the correction parameters α ₁ and α ₂ from taking extreme values, respectively, and the respective standard values α ₁ ′ and α ₂ ′ are Is calculated as the square of the difference between The standard values α ₁ ′, α ₂ ′ are correction parameters α ₁ , α ₂ calculated for, for example, a charge that has been processed most recently and whose operating conditions (end point component / temperature, initial hot metal component / temperature, etc.) are close. The average value of is used. The calculated values of the correction parameters α ₁ and α ₂ are stored in the performance DB 12 and used in the subsequent calculation of the standard values α ₁ ′ and α ₂ ′ of charge. Further, σ _f , σ _g , σ ₁ , and σ ₂ in the evaluation values shown in the mathematical formula (4) are setting parameters and take fixed values. This setting parameter may be set to a different value for each operation condition. In this optimization problem, the evaluation value shown in Equation (4) is minimized after satisfying the constraint condition shown in Equation (3). The minimization problem using the evaluation value shown in Equation (4) can be solved by using a nonlinear optimization method (for example, see Non-Patent Document 1 (by Hiroshi Imano, Hiroshi Yamashita: Nonlinear Programming, Nikka Giren)). . In general minimization problems, it is difficult to calculate a strict (global) optimal solution if the conditions are not met. In such a case, a local optimal solution (with an evaluation function within the search range) The solution to be minimized is often the optimal solution. If it is difficult to obtain a global optimum solution with this technique, correction parameters α ₁ and α ₂ that minimize the evaluation value in a local range may be used. Non-Patent Document 1 lists methods for calculating various local optimum solutions. Thereby, the process of step S3 is completed and the refining process state estimation process proceeds to the process of step S4.

In the process of step S4, the substance balance calculation part 16 estimates and calculates the carbon concentration in the molten metal at time t + 1 1 second after the current time t using the following formula (7). In Equation (7), C _t represents the carbon concentration (%) in the molten metal at time t, and W _total represents the total molten metal weight (ton). Moreover, in Formula (7), it is assumed that the amount of carbon input / output of the molten metal is very small compared to the total amount of charge. Further, the second term on the right side of the mathematical formula (7) indicates that the carbon concentration in the molten metal is increased by the amount of the auxiliary material containing carbon, and the carbon in the molten metal by the amount (contained in CO and CO ₂ ) discharged as exhaust gas. It means that the concentration decreases. Further, the amount of exhaust gas is corrected by multiplying the carbon content contained in the exhaust gas by the correction parameters α ₁ and α ₂ calculated in the process of step S3.

  Thereafter, the arithmetic processing unit 13 sends the estimation result of the carbon concentration in the melt by the material balance calculation unit 16 to the output device 14. The output device 14 outputs the estimation result of the carbon concentration in the molten metal sent from the arithmetic processing unit 13 to the control terminal 10 and the display device 20. The control terminal 10 adjusts the operation amount of the refining equipment 2 based on the estimation result of the carbon concentration in the molten metal. The display device 20 displays the estimation result of the carbon concentration in the molten metal. Thereby, the process of step S4 is completed and the refining process state estimation process proceeds to the process of step S5.

  In the process of step S5, the arithmetic processing unit 13 determines whether or not there is a measured value and an analytical value of the carbon concentration in the new molten metal. As a result of the determination, when there are a measured value and an analytical value of the carbon concentration in the new molten metal (step S5: Yes), the arithmetic processing unit 13 returns the refining process state estimation process to the process of step S1. On the other hand, when there is no measurement value and analysis value of the carbon concentration in the new molten metal (step S5: No), the arithmetic processing unit 13 advances the refining process state estimation process to the process of step S6.

  In the process of step S6, the arithmetic processing unit 13 determines whether or not the blowing process has been completed. As a result of the determination, when the blowing process is finished (step S6: Yes), the arithmetic processing unit 13 finishes a series of refining process state estimation processes. On the other hand, when the blowing process has not ended (step S6: No), the arithmetic processing unit 13 advances the refining process state estimation process to the process of step S7.

  In the process of step S <b> 7, the arithmetic processing unit 13 acquires the latest values of the exhaust gas measurement / analysis information and the auxiliary material input amount information from the control terminal 10. Thereby, the process of step S7 is completed and the refining process state estimation process returns to the process of step S3.

  As is clear from the above description, according to the refining process state estimation process that is one embodiment of the present invention, the correction calculation unit 15 outputs the measurement result of the component concentration of the molten metal before or during the treatment, Correction parameter to correct the measured value of the flow rate of exhaust gas discharged from the refining equipment and the measured concentration of component in the exhaust gas based on the measurement result of the exhaust gas flow rate and the component concentration in the exhaust gas and the balance calculation result of carbon and oxygen The substance balance calculation unit 16 calculates the correction parameter, the flow rate of the exhaust gas and the measurement result of the component concentration in the exhaust gas, the amount of blown oxygen, the weight and component concentration of the molten metal before the treatment, and the auxiliary material introduced during the treatment. Based on the weight of the molten metal, the component concentration in the molten metal and the slag is estimated by calculating the material balance for each component in the molten metal. Thereby, the estimation precision of the component density | concentration in molten metal and slag can be improved.

As mentioned above, although embodiment which applied the invention made | formed by this inventor was described, this invention is not limited with the description and drawing which make a part of indication of this invention by this embodiment. For example, in the above embodiment, the estimation calculation of the carbon concentration has been described, but it is also possible to estimate the oxygen amount in the slag (FeO generation amount) using the mass balance calculation regarding oxygen. Also in this case, the measurement error of the exhaust gas information is appropriately corrected by performing the mass balance calculation using the correction parameters α ₁ and α ₂ described above. Furthermore, the temperature of the molten metal can be estimated continuously by using a heat balance model based on the amount of heat generated by the oxidation reaction. As described above, other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.

1 refining process state estimation device 2 refining equipment 10 control terminal 11 input device 12 results database (results DB)
DESCRIPTION OF SYMBOLS 13 Arithmetic processing part 14 Output device 15 Correction calculation part 16 Material balance calculation part 20 Display apparatus 100 Converter 101 Molten metal 102 Lance 103 Slag 104 Duct 105 Exhaust gas detection part 106 Vent hole 107 Flowmeter

Claims (5)

Result of measurement of component concentration of molten metal being processed in refining equipment, flow rate of exhaust gas discharged from refining equipment, measurement result of component concentration in exhaust gas, information on amount of oxygen blown into furnace of refining equipment, processing An input device for inputting information on the weight and component concentration of the previous molten metal, and information on the weight of the auxiliary raw material charged during processing;
Based on the measurement result of the component concentration of the molten metal before or during the treatment, the flow rate of the exhaust gas discharged from the refining equipment, the measurement result of the component concentration in the exhaust gas, and the balance calculation result of carbon and oxygen, the refining equipment A correction calculation unit for calculating a correction parameter for correcting the flow rate of the exhaust gas discharged from the exhaust gas and the measured value of the component concentration in the exhaust gas;
Based on the correction parameter, the flow rate of the exhaust gas and the measurement result of the component concentration in the exhaust gas, the amount of oxygen blown in, the weight and component concentration of the molten metal before the treatment, and the weight of the auxiliary material charged during the treatment, A material balance calculation unit that estimates the concentration of the component in the molten metal and slag by calculating the material balance for each component in the component,
A refining process state estimation device comprising:   The correction calculation unit is an evaluation function based on the difference between the amount of carbon in the molten metal and the amount of carbon in the exhaust gas in the specified period during processing calculated from the component analysis value of the molten metal and the amount of carbon contained in the added auxiliary material, and 2. The refining process state estimation apparatus according to claim 1, wherein a correction parameter that minimizes an evaluation function based on a balance of the amount of oxygen used for carbon combustion is calculated.   The evaluation function is a weighted sum including, as terms, a square value of a difference between a carbon decrease amount in a molten metal and a carbon amount in exhaust gas, and a value based on a balance about an oxygen amount used for carbon combustion. The refining process state estimation apparatus according to claim 2. Result of measurement of component concentration of molten metal being processed in refining equipment, flow rate of exhaust gas discharged from refining equipment, measurement result of component concentration in exhaust gas, information on amount of oxygen blown into furnace of refining equipment, processing An input step for inputting information on the weight and component concentration of the previous molten metal, and information on the weight of the auxiliary raw material charged during the processing;
Based on the measurement result of the component concentration of the molten metal before or during the treatment, the flow rate of the exhaust gas discharged from the refining equipment, the measurement result of the component concentration in the exhaust gas, and the balance calculation result of carbon and oxygen, the refining equipment A correction calculation step for calculating a correction parameter for correcting the flow rate of the exhaust gas discharged from the exhaust gas and the measured value of the component concentration in the exhaust gas;
Based on the correction parameter, the flow rate of the exhaust gas and the measurement result of the component concentration in the exhaust gas, the amount of oxygen blown in, the weight and component concentration of the molten metal before the treatment, and the weight of the auxiliary material charged during the treatment, A substance balance calculation step for estimating a component concentration in the molten metal and slag by calculating a substance balance for each component in the component;
The refining process state estimation method characterized by including.   A method for producing a molten metal comprising a step of adjusting a component concentration in the molten metal within a desired range based on a component concentration in the molten metal estimated using the refining process state estimating method according to claim 4. .

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