TWI553123B - Control apparatus and control method of converter blowing equipment - Google Patents

Description

Control device and control method for converter blowing equipment

The present invention relates to a control device and a control method for a converter blowing apparatus, which controls the amount of oxygen supplied to the charge after sampling at the time of the blowing process, so that the carbon in the molten steel at the end of the blowing process The concentration reaches the target carbon concentration.

In the converter blowing equipment used in the steel plant, the impurities in the molten steel are removed and heated by the blowing treatment of blowing oxygen into the molten steel, thereby the composition of the molten steel at the end of the blowing treatment and The temperature is controlled so that it is within the specified range. However, at the time of the blowing treatment, the oxidation reaction in the molten steel is increased, and the molten steel reaches a high temperature, so that it is difficult to measure the composition and temperature of the molten steel at all times.

Therefore, in actual work, the carbon concentration in the molten steel at the sampling point is estimated based on the composition analysis result of the molten steel during the sampling of the blowing process, and the carbon concentration and decarburization in the molten steel are estimated. The oxygen efficiency model formula calculates the amount of oxygen to be supplied (hereinafter referred to as the required oxygen supply amount) after the sampling time in order to set the composition and temperature of the molten steel within the specified range. Furthermore, the decarburization efficiency model formula is a formula for calculating the decarburization efficiency by using the carbon concentration in the molten steel. The decarburization efficiency refers to the amount of carbon discharged to the outside of the converter per unit of oxygen amount blown into the converter. through Often, if the carbon concentration in the molten steel is high, the decarburization efficiency is increased.

Further, in the decarburization efficiency model formula, there is a setting parameter, and the value of the setting parameter is changed according to the working condition during the operation, and the decarburization efficiency is calculated according to the decarburization efficiency model formula in which the value of the setting parameter is changed. . However, the relationship between the carbon concentration in the molten steel and the decarburization efficiency expressed by the decarburization efficiency model formula is complicated not only by the working conditions but also by various factors including time changes and seasonal changes. Therefore, it is generally difficult to appropriately change the setting parameters of the decarburization efficiency model formula and calculate the decarburization efficiency with high precision.

Due to the background as described above, a method for appropriately setting the setting parameters of the decarburization efficiency model formula has been proposed. Specifically, Patent Document 1 describes a method of selecting a past charge having a working condition close to that of the next charge so as to minimize the total value of the error between the carbon concentration and the actual value in the molten steel at the end of the blowing process. The method determines the setting parameter of the decarburization oxygen efficiency model formula, and the carbon concentration in the molten steel at the end of the blowing treatment is a model formula of carbon concentration and decarburization efficiency in the molten steel during the blowing process of the selected past charge. Calculated. Further, Patent Document 2 describes a method for determining a maximum decarburization efficiency and a decarburization efficiency reduction coefficient, which are set parameters of a decarburization efficiency model formula, using a regression equation of operating conditions, and discloses exhaust gas measurement information. It is effective to use the determination of the coefficient of the regression equation.

Prior art literature

Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2010-7150

Patent Document 2: Japanese Patent Laid-Open Publication No. 2012-117090

However, the method described in Patent Document 1 determines the setting parameter of the decarburization efficiency model formula using only the working conditions and the component analysis values of the sampled molten steel. Therefore, variations in the progress of the blowing treatment reaction due to various external disturbances or unmeasured information cannot be considered, and there is a limitation in improving the accuracy. Further, as the external disturbance or unmeasured information, components or yields, measurement errors, and the like of the excipients introduced into the molten steel can be exemplified. In addition, there is an exhaust gas flow rate or a component analysis value as one index for realizing the change in the transition of the blowing treatment reaction in real time. However, Patent Document 1 does not disclose the use of such information.

On the other hand, in the method described in Patent Document 2, the change in the blowing process reaction is considered by including the amount of stored oxygen in the furnace calculated by the exhaust gas measurement information in the explanatory variable of the primary regression equation. However, it is difficult to express the setting parameters of the decarburization oxygen efficiency model formula expressed by the nonlinear equation with high precision using one regression equation. Therefore, according to the method described in Patent Document 2, the calculation accuracy of the decarburization efficiency obtained by the decarburization efficiency model formula may be lowered.

In addition, it is conceivable that the setting parameters can be expressed with high precision if the exhaust gas measurement information is processed. However, in Patent Document 2, there is no specific processing method of the exhaust gas measurement information. description. Further, in order to perform the regression calculation, it is necessary to calculate the optimum maximum decarburization efficiency and the decarburization efficiency reduction coefficient for the past charge in advance, but there is no specific description of the calculation method in Patent Document 2.

Further, the value of the setting parameter of the decarburization efficiency model formula is not necessarily limited to that it does not change during the blowing process of the 1 charge portion. According to the data analysis by the inventors and the like, the following findings are obtained: in particular, when the flow rate of the stirring gas blown into the converter changes in the charge, the set parameter of the decarburization efficiency model formula is affected by the flow rate of the stirred gas. And it has changed. However, the methods described in Patent Document 1 and Patent Document 2 do not take into consideration the change in the value of the setting parameter during the blowing process of the one charge portion. Therefore, according to the methods described in Patent Document 1 and Patent Document 2, the calculation accuracy of the decarburization efficiency obtained by the decarburization efficiency model formula may be lowered.

The present invention has been made to solve the above problems, and an object of the invention is to provide a control device and a control method for a converter blowing apparatus, which are capable of calculating the decarburization efficiency with high precision and melting at the end of the blowing process. The carbon concentration in the steel is controlled to a target carbon concentration with high precision.

In order to achieve the object of solving the above problems, the control device for the converter blowing apparatus of the present invention controls the amount of oxygen supplied to the charge after the sampling point in the middle of the blowing process so that the carbon in the molten steel at the end of the blowing process The concentration control reaches the target carbon concentration, and the control device of the converter blowing apparatus is characterized by comprising: a model formula calculation unit that calculates the decarburization oxygen efficiency by using a model formula, wherein the model formula sets at least the carbon concentration and the agitation gas flow rate in the molten steel. For the input variable, the decarburization efficiency is set as the output variable, and has one or more setting parameters. The model parameter correction unit uses the melting point at the time of sampling during the blowing process for the plurality of past charges that have been completed in the blowing process. steel At least one of the set parameters is corrected for the medium carbon concentration, the flow rate of the exhaust gas, the component concentration of the exhaust gas, the carbon concentration in the molten steel at the end of the blowing process, the flow rate of the exhaust gas, and the component concentration of the exhaust gas; The processing weight calculation unit is based on the difference between the operating conditions of the plurality of past charges that have been completed in the blowing process and the operating conditions of the charge during the blowing process, and the time during which the charge in the middle of the blowing process is sampled during the blowing process. The similarity of the model formula of the past charge, the weight of each past charge is calculated; the model parameter generation unit during the blowing process uses the setting parameters of each of the past charge corrected by the model parameter correction unit and by the In the past, the weight of each of the past charges calculated by the processing weight calculation unit is used to calculate the setting parameter of the charge during the blowing process, and the oxygen supply amount calculation unit calculates the blowing after the sampling time in the middle of the blowing process by the decarburization efficiency. The amount of oxygen supplied to the charge during the refining process, wherein the decarburization efficiency is measured by the model formula calculation unit at the time of sampling during the blowing process The carbon concentration in the molten steel, the target carbon concentration, and the setting parameters calculated by the model parameter generating unit in the blowing process are calculated.

A control device for a converter blowing apparatus according to the present invention is characterized in that: the model parameter correcting unit corrects the setting parameter so that the carbon concentration in the molten steel measured at the point of sampling during the blowing process is When the model formula is established, the difference in carbon concentration in the molten steel at the time of sampling in the middle of the blowing process, the carbon concentration in the molten steel measured at the end of the blowing process, and the blowing process in which the model formula is established are completed. The difference in the carbon concentration in the molten steel and the weighted squared sum of the differences between the set parameters and the standard values are minimized.

The control device of the converter blowing apparatus of the present invention is characterized by the invention described above In the past processing weight calculation unit, the flow rate of the stirring gas per unit weight of the molten steel before the end of the sampling process and the end of the blowing process is included in the working conditions.

In order to achieve the object of solving the above problems, the control method of the converter blowing apparatus of the present invention is to control the amount of oxygen supplied to the charge after the sampling point in the middle of the blowing process so that the molten steel at the end of the blowing process The medium carbon concentration reaches the target carbon concentration, and the control method of the converter blowing apparatus is characterized by comprising: a correction step of using carbon in the molten steel at the time of sampling during the blowing process for the plurality of past charges that have been completed in the blowing process Correcting at least one setting parameter of the model formula by the concentration, the flow rate of the exhaust gas, the component concentration of the exhaust gas, the carbon concentration in the molten steel at the end of the blowing process, the flow rate of the exhaust gas, and the component concentration of the exhaust gas, The model formula sets at least the carbon concentration and the agitation gas flow rate in the molten steel as input variables, and the decarburization oxygen efficiency as an output variable; the weight calculation step, according to the working conditions and the blowing treatment of the plurality of past charge materials that have been completed by the blowing process The difference in the working conditions of the charge during the process, and the model of the charge in the middle of the blowing process relative to the previous charge at the point of sampling during the blowing process The similarity of the formula is used to calculate the weight of each of the past charges; the parameter calculation step is calculated by using the set parameters of the past charge corrected in the correction step and the weights of the respective charge calculated in the weight calculation step. The setting parameter of the charge during the blowing process; and the oxygen-removing oxygen efficiency is used to calculate the oxygen supply amount of the charge during the blowing process after the sampling time in the middle of the blowing process, and the decarburization efficiency is utilized in blowing The carbon concentration in the molten steel measured at the sampling point in the process, the target carbon concentration, and the set parameters calculated in the parameter calculation step, according to the model Calculated by the formula.

According to the control device and the control method of the converter blowing apparatus of the present invention, by calculating the decarburization efficiency with high precision, the carbon concentration in the molten steel at the end of the blowing process can be accurately controlled to the target carbon concentration.

10‧‧‧Control terminal

20‧‧‧Database Server (DB Server)

20a‧‧‧Working database (job DB)

20b‧‧‧Main Information Database (Main Information DB)

20c‧‧‧Parameter database (parameter DB)

30‧‧‧Control device

31‧‧‧Input and Output Department

32‧‧‧First Processing Department

32a‧‧‧Model Parameter Correction Department

33‧‧‧2nd Processing Department

33a‧‧‧Processing Weight Calculation Department

33b‧‧‧Model parameter generation department during the blowing process

33c‧‧‧Oxygen supply calculation department

34‧‧‧Model Formula Calculation Department

40‧‧‧ Input device

50‧‧‧ display device

100‧‧‧ converter

101‧‧‧Fused steel

102‧‧‧ spray gun

103‧‧‧ slag

104‧‧‧ catheter

105‧‧‧Exhaust detection department

106‧‧‧Exhaust flowmeter

107‧‧‧Ventinel

108‧‧‧ Flowmeter

S1~S4, S11~S17‧‧‧ steps

1 is a schematic diagram showing a configuration of a converter blowing device and a control system to which a control device and a control method of a converter blowing device according to an embodiment of the present invention are applied.

Fig. 2 is a block diagram showing the configuration of the control device shown in Fig. 1;

3 is a view showing an example of a function of an influence coefficient of a stirring gas.

Fig. 4 is a graph showing the relationship between the carbon concentration in the molten steel and the decarburization efficiency.

Fig. 5 is a flowchart showing the flow of model parameter correction processing as an embodiment of the present invention.

Fig. 6 is a flowchart showing the flow of oxygen supply amount calculation processing according to an embodiment of the present invention.

Fig. 7 is a view showing an example of the relationship between the unit stirring gas flow rate and the cumulative oxygen supply amount.

Hereinafter, a control device and a control method of a converter blowing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[Composition of converter blowing equipment]

First, a configuration of a converter blowing device to which a control device and a control method of a converter blowing device according to an embodiment of the present invention are applied will be described with reference to Fig. 1 .

1 is a schematic diagram showing a configuration of a converter blowing device and a control system to which a control device and a control method of a converter blowing device according to an embodiment of the present invention are applied. As shown in FIG. 1, in a converter blowing apparatus to which a control device and a control method of a converter blowing apparatus according to an embodiment of the present invention are applied, a lance 102 is disposed on a molten steel 101 in the converter 100, and The front end portion of the spray gun 102 ejects high-pressure oxygen to the molten steel 101. The high-pressure oxygen gas ejected from the lance 102 causes the impurity component in the molten steel 101 to be oxidized and enters the slag 103 (blowing treatment).

A duct 104 for exhaust gas guiding is provided in an upper portion of the converter 100, and an exhaust detecting unit 105 and an exhaust flow meter 106 are provided inside the duct 104, and the exhaust detecting unit 105 is used to The concentration of each component (for example, CO, CO ₂ , O ₂ , N ₂ , H ₂ O, Ar, etc.) of the exhaust gas discharged along with the blowing process is detected, and the exhaust flow meter 106 is used to align The flow of gas is measured. The flow rate of the exhaust gas is obtained by measuring the differential pressure between the upstream and downstream of a Venturi tube or an orifice, and calculating based on the measured value. Since the exhaust gas is a gas and the volume changes due to temperature or pressure, the calculated value is converted into a gas flow rate in a standard state (for example, a temperature of 0 ° C and a pressure of 1 atm).

In the molten steel 101 in the converter 100, Ar gas as an inert gas is blown through a vent hole 107 formed in the bottom of the converter 100, and the molten steel 101 is stirred by Ar gas, thereby promoting high-pressure oxygen and molten steel 101. Reaction. The flow rate of the Ar gas blown into the molten steel 101 (stirring gas flow rate) is obtained by using the flow meter 108 measuring. The temperature and composition of the molten steel 101 are temporarily measured during the blowing process, and the supply amount (oxygen supply amount) of high pressure oxygen, the supply speed (oxygen delivery rate), the flow rate of the agitation gas, and the like are determined based on the measured information. Further, the temperature and composition of the molten steel 101 are analyzed immediately before the start of the blowing process and after the completion of the blowing process. Usually, the operation amount of the blowing treatment is temporarily set before the start of the blowing treatment, and is corrected after obtaining the measured value of the temperature and composition of the molten steel in the middle of the blowing treatment. The present invention relates to the determination of the amount of oxygen supplied to the latter.

[Composition of control system]

Next, a configuration of a control system of a converter blowing apparatus to which a control device and a control method of a converter blowing apparatus according to an embodiment of the present invention are applied will be described with reference to FIG.

As shown in FIG. 1, a control system of a converter blowing apparatus to which a control device and a control method of a converter blowing apparatus according to an embodiment of the present invention is applied includes a control terminal 10, a database server (DB server) 20, The control device 30, the input device 40, and the display device 50 are main components.

The control terminal 10 is composed of an information processing device such as a personal computer or a work station. The control terminal 10 controls the oxygen supply amount, the oxygen supply rate, the agitation gas flow rate, the height of the spray gun 102, and the auxiliary material input amount so that the component concentration of the molten steel 101 reaches a desired range, and the oxygen supply amount is collected and sent. The data on the actual value of the oxygen velocity, the agitated gas flow rate, the height of the spray gun, and the amount of the auxiliary input were used as the operation amount.

The DB server 20 includes a job database (job DB) 20a, main information Database (master information DB) 20b and parameter database (parameter DB) 20c.

The work DB 20a stores work time information other than the relevant time series and time series of the past charge that has been completed in the blowing process, and job performance information other than the time series and the time series of the charge during the execution of the blowing process. The time series of performance information includes information on the actual amount of operation (oxygen delivery rate, oxygen delivery rate, agitated gas flow rate, spray gun height, and time series information of the auxiliary material input amount), and information on the operation amount plan (scheduled oxygen supply amount, The scheduled oxygen delivery rate, the predetermined agitation gas flow rate, the predetermined spray gun height, and the time series information of the predetermined auxiliary material input amount, and the relevant information of the exhaust performance (time series information of the component concentration and flow rate of the exhaust gas). The actual performance information other than the time series includes specification information (melt iron information (steel type), manufacturing specifications (target carbon concentration, target temperature)), and information on the planned operation amount (predetermined total oxygen supply amount, total predetermined auxiliary material input amount, The amount of the predetermined stirring gas, and the actual value of the total oxygen supply amount, and the relevant information of the composition concentration and temperature of the molten steel before and after the blowing treatment and the blowing process.

The main information DB 20b stores data such as physical constants, threshold values, setting parameters, and the like required to execute the model parameter correction processing and the oxygen supply amount calculation processing described below.

The parameter DB 20c stores setting parameters of the decarburization oxygen efficiency model formula corrected for each of the past charges in the model parameter correction processing described below.

The control device 30 sets the actual operation amount collected by the control terminal 10 and the component concentration and flow rate (exhaust performance) of the exhaust gas measured by the exhaust gas detecting unit 105 and the exhaust gas flow meter 106. In the blowing process, the charge information is calculated according to the charge information in the blowing process, and the calculation result is output to the control. Terminal 10 or display device 50. The detailed configuration of the control device 30 will be described later.

The input device 40 is constituted by an input device such as a keyboard or a mouse pointer, and is operated when various kinds of information related to the following processing are input. The display device 50 is constituted by a display device such as a cathode ray tube (CRT) or a liquid crystal display, and displays various processing results of the control device 30.

[Composition of control device]

Next, the configuration of the control device 30 will be described with reference to Fig. 2 .

FIG. 2 is a block diagram showing a configuration of a control device 30 according to an embodiment of the present invention. As shown in FIG. 2, the control device 30 according to an embodiment of the present invention includes an input/output unit 31, a first processing unit 32, a second processing unit 33, and a model formula calculation unit 34. The input/output unit 31 controls transmission and reception of information between the control device 30 and an external device. The first processing unit 32, the second processing unit 33, and the model formula calculation unit 34 are realized by executing a computer program by the arithmetic processing unit in the control device 30. The first processing unit 32 includes a model parameter correction unit 32a. The second processing unit 33 includes a past processing weight calculation unit 33a, a model parameter generation unit 33b during the blowing process, and a oxygen supply amount calculation unit 33c. The functions of each of these sections will be described later.

The control device 30 having the above-described configuration performs the model parameter correction processing and the oxygen supply amount calculation processing described below, thereby accurately calculating the decarburization efficiency and thereby carbon in the molten steel at the end of the blowing treatment. The concentration is controlled to a target carbon concentration with high precision. Hereinafter, the operation of the control device 30 when the model parameter correction processing and the oxygen supply amount calculation processing are executed will be described.

[Model parameter correction processing]

First, a flow of model parameter correction processing as an embodiment of the present invention will be described with reference to Figs. 3 to 5 .

In the control device 30 according to the embodiment of the present invention, the model parameter correcting unit 32a obtains the decarburization efficiency model used in the work when the work performance information of the charge that has been completed in the blowing process is obtained via the input/output unit 31. The setting parameters of the formula are corrected to be consistent with the job performance information.

In the present embodiment, the decarburization efficiency model formula is described by a nonlinear function or an interval linear function, and is expressed, for example, by the formula (1) and the formula (2) shown below. The following formula (1) is used to calculate the amount of consumption per unit of oxygen supply (Nm ³ /ton: the oxygen supply amount [Nm ³ ] divided by the weight of the molten steel to be treated [ton]) The formula for the amount of carbon concentration reduction (%) in molten steel. In the formula (1), the parameter C is the carbon concentration in the molten steel, and k, q, and p are setting parameters. Further, the parameter α is an influence coefficient of the stirring gas (Ar gas), and is expressed by the stirring gas flow rate unit (Nm ³ /Hr/ton: dividing the stirring gas flow rate by the following formula (2) The value determined by the treatment of the weight of the molten steel of the object) V _b . The value of the agitation gas influence coefficient α can be given by a table or by a continuous function. A function of the agitation gas influence coefficient α is exemplified in Fig. 3 . At this time, the model parameter correcting unit 32a reads the setting parameters of the function from the autonomous information DB 20b.

[Expression 1]

[Expression 2] α = f (V _b ) (2)

Fig. 4 is a graph showing the equation (1) when the stirring gas influence coefficient α is fixed. As shown in FIG. 4, as the value of the carbon concentration C in the molten steel increases, the decarburization oxygen efficiency dC/dO ₂ rises. However, the decarburization efficiency dC/dO ₂ does not exceed the set parameter k. The reason for this is that, in a state in which the carbon concentration C in the molten steel is sufficient, the amount of oxygen to be blown forms a restriction on the amount of decarburization. Further, if the carbon concentration C in the molten steel is lower than the set parameter q, the decarburization efficiency is 0, which means that if the carbon concentration C in the molten steel does not reach the value of the set parameter q or more, the decarburization reaction itself does not occur. Further, when the setting parameter p is changed, as shown in Fig. 4, the decarburization reaction rate changes.

In the decarburization efficiency model formula shown by the formula (1), the set parameter p is multiplied by the agitation gas influence coefficient α. Therefore, if the value of the agitation gas influence coefficient α becomes small, the decarburization reaction rate increases. In the present invention, the model accuracy is improved by introducing the stirring gas influence coefficient α into the decarburization oxygen efficiency model formula. The setting parameters are three, k, p, and q, but it is sufficient to correct which setting parameter is to be determined for each charge as long as it is based on the characteristics of the target converter equipment. In the present embodiment, the value of the setting parameter k is fixed, and only the setting parameter p and the setting parameter q are corrected. That is, the parameter p and the setting parameter q will be set. The standard value is P and Q, and the correction amount is δp and δq, and the standard value P and the standard value Q are corrected by the combination of the following equations (3) and (4).

[Expression 3] P+δp...(3)

[Expression 4] Q+δq...(4)

Hereinafter, the flow of the model parameter correction processing which is one embodiment of the present invention will be specifically described with reference to Fig. 5 .

Fig. 5 is a flowchart showing the flow of model parameter correction processing as an embodiment of the present invention. The flowchart shown in FIG. 5 starts with the timing at which the blowing process has ended, and the model parameter correction processing proceeds to the processing of step S1.

In the process of step S1, the model parameter correcting unit 32a obtains the work performance information of the charge that has been subjected to the blowing process via the input/output unit 31. Thereby, the process of step S1 is completed, and the model parameter correction process proceeds to the process of step S2.

In the process of step S2, the model parameter correcting unit 32a calculates the carbon concentration (analytical value) C _s and the decarburized oxygen in the molten steel at the time of sampling at the time of the blowing process by using the work performance information obtained in the process of step S1. The efficiency dC _s /dO ₂ and the stirring gas influence coefficient α _s , and the carbon concentration (analytical value) C _e in the molten steel at the end of the blowing treatment, the decarburization oxygen efficiency dC _e /dO ₂ , and the stirring gas influence coefficient α _e .

Specifically, when the carbon concentration in the molten steel at the point of sampling during the blowing process and the carbon concentration in the molten steel at the end of the blowing treatment are respectively C _s and C _e , the point at the time of sampling during the blowing process is taken off. The carbon-oxygen efficiency dC _s /dO ₂ and the decarburization oxygen efficiency dC _e /dO ₂ at the end of the blowing treatment can be obtained by the exhaust gas performance at the time of sampling during the blowing process and the exhaust performance at the end of the blowing, according to the following The equation (5) is shown to calculate.

Among them, the time delay caused by the analysis of the flow rate and component concentration of the exhaust gas has been considered. Further, the stirring gas influence coefficient α _{s at the} sampling point in the middle of the blowing process and the stirring gas influence coefficient α _e at the end of the blowing process can be respectively consumed by the agitating gas flow rate unit amount _{B b at the} time of sampling in the middle of the blowing process. And the stirring gas flow rate unit consumption amount V _b at the end of the blowing process is substituted into the formula (2). Thereby, the process of step S2 is completed, and the model parameter correction process proceeds to the process of step S3.

[Expression 5] dC/dO ₂ =V _ex ×ρ _c /22.4*12.0/1000/V _o (5)

Here, in the formula (5), the parameter V _ex , the parameter V _o , and the parameter ρ _c respectively represent the exhaust gas flow rate [Nm ³ /Hr], the oxygen supply flow rate [Nm ³ /Hr], and the row in the analysis of the molten steel. The sum of the concentrations of CO gas and CO ₂ gas in the gas [%]. When a large amount of noise is included in the measured values, the value to which the filtering process has been applied, such as a moving average value, may be used instead of the corrected value of the biased error.

In the process of step S3, the model parameter correcting unit 32a corrects the setting parameter p and the setting parameter q by using the value calculated in the process of step S2 so that the sampling time and the blowing process are completed during the blowing process. The error of the decarburization efficiency calculated from the decarburization efficiency model formula is reduced as much as possible with respect to the actual value. However, when the setting parameter p and the setting parameter q are corrected, the setting parameter p and the setting parameter q are not largely deviated from the standard value P and the standard value Q. In the present embodiment, the setting parameter p and the setting parameter q are corrected using the error function J shown in the following equation (6) from the viewpoint of the easiness of the calculation processing.

Here, the first term and the second term in the formula (6) respectively represent the decarburization oxygen efficiency model formula at the time of sampling during the blowing process and the decarburization oxygen efficiency model formula at the end of the blowing process. Error in decarburization efficiency. The difference between the two sides of the equation of the equation (6) obtained by substituting the processing result of step S2 into the equation (1) and shifting the term to calculate the logarithm of the two sides is obtained as the first term and the second term of the equation (6). Further, the third term and the fourth term of the equation (6) are added to prevent the setting parameter p and the setting parameter q from largely deviating from the standard value P and the standard value Q. The parameter σ _s , the parameter σ _e , the parameter σ _p , and the parameter σ _q in the equation (6) are values set by the user of the device, and if the parameter value is set to be small, the equation (6) can be reduced. The error of the denominator of the corresponding term. As an example of the setting method of the parameter, there is a method of calculating a denominator value of each item of the formula (6) for a plurality of past charges, and calculating a standard deviation with respect to the respective denominator values, and setting the values of the respective denominators Is the set value of the parameter.

In the above-described processing, the correction amount δp of the setting parameter p and the correction amount δq of the setting parameter q are determined such that the error function J is minimized, but the error function J is the correction amount δp and the correction amount δq twice. Polynomial, so the minimum solution can be calculated by inverse matrix calculation. Specifically, first, the error function J is expressed by the following equation (7). Here, in the equation (7), x is a two-dimensional row vector with the correction amount δp and the correction amount δq as elements, D is a constant array of 2×2, E is a two-dimensional constant row vector, and F is a constant without vector. item. The T attached to the right shoulder of the vector refers to the transposition.

[Expression 7] J=x ^T Dx+E ^T x+F...(7)

When the error function J is expressed by the equation (7), the error function J takes a minimum value when the equation (8) shown below is established.

[Expression 8]

When the equation (8) is deformed, the following equation (9) is obtained.

By the calculation, the correction amount δp and the correction amount δq which minimize the error function J can be calculated. Therefore, the correction amount δp and the correction amount δq are obtained by the equations (3) and (4). Correct the setting parameter p and setting parameter q. In addition, even when the error function J different from the equation (7) is used, the correction calculation of the setting parameter p and the setting parameter q can be performed by using the nonlinear optimization method or the like. Thereby, the process of step S3 is completed, and the model parameter correction process proceeds to the process of step S4.

In the process of step S4, the model parameter correcting unit 32a stores the setting parameter p and the setting parameter q corrected by the process of step S3 to the parameter DB 20c via the input/output unit 31. Thereby, the processing of step S4 ends, and a series of model parameter correction processing ends.

[Oxygen supply calculation process]

Next, an oxygen supply amount as an embodiment of the present invention will be described with reference to Figs. 6 and 7 . The flow of the calculation process will be described.

Fig. 6 is a flowchart showing the flow of oxygen supply amount calculation processing according to an embodiment of the present invention. The flowchart shown in FIG. 6 starts with the timing at which the control device 30 has obtained the molten steel analysis result at the time of sampling in the middle of the blowing process, and the oxygen supply amount calculation process proceeds to the process of step S11.

In the process of step S11, the past processing weight calculation unit 33a reads the work performance information of the past charge and various setting values from the work DB 20a and the main information DB 20b, respectively. Thereby, the process of step S11 is completed, and the oxygen supply amount calculation process proceeds to the process of step S12.

In the process of the step S12, the past process weight calculation unit 33a selects only the same type of charge from the past charge as the charge in the middle of the blowing process. Here, the charge is the same type, and is, for example, the same as the following points. Thereby, the process of step S12 is completed, and the oxygen supply amount calculation process advances to the process of step S13.

(1) The same purpose of treatment: one of P-blowing, C-blowing, and ordinary blowing (simultaneous P-blowing and C-blowing)

(2) The final target carbon concentration and target temperature belong to the same range (the threshold of the range has been stored in the main information DB 20b)

(3) The execution date of the blowing process is from the current to the specified number of days

In the process of step S13, the previous processing weight calculation unit 33a calculates the difference value between the working condition of the past charge selected in the process of step S12 and the working condition of the charge during the blowing process, and the difference value of the working condition Sort the past charge from small to large, choose the beginning of the sorted past charge From the previous charge of the specified number N. Further, the difference value can be calculated, for example, by the following formula (10). ε(i) shown in the following formula (10) indicates the difference between the working condition of the i-th past charge and the working condition of the charge during the blowing process, and is composed of a weighted sum of the square values of the difference in the working conditions.

In the formula (10), the parameter x _p (p=1 to n) indicates the p-th work performance information of the charge in the middle of the blowing process (measurement information of the molten steel before the blowing process, and the point at the time of sampling during the blowing process) The analysis value of the molten steel, the operation amount at the time of sampling during the blowing process (stirring gas flow rate, etc.), and the predetermined operation amount (stirring gas flow rate, etc.) at the end of the blowing process, the parameter x' _i,p represents the i-th past charge The p-th work performance information (measurement information of the molten steel before the blowing treatment, the analysis value of the molten steel at the time of sampling during the blowing process, the operation amount at the time of sampling during the blowing process (stirring gas flow rate, etc.) and blowing At the end of the refining process, the actual amount of operation (stirring gas flow rate, etc.), and the parameter W _p represents the weight coefficient. The smaller the value of ε(i), the more similar the operating conditions of the past charge to the operating conditions of the charge during the blowing process. Thereby, the process of step S13 is completed, and the oxygen supply amount calculation process proceeds to the process of step S14.

[Expression 10] ε(i)=W ₁ ×(x ₁ -x' _i,1 )^2+W ₂ ×(x ₂ -x' _i,2 )^2+W ₃ ×(x ₃ -x ' _i,3 )^2+...+W _n ×(x _n -x' _i,n )^2...(10)

In the process of step S14, the previous processing weight calculation unit 33a calculates the value d _i (i=1 to N) represented by the following equation (11) for the N past charges selected in the process of step S13. . The value d _i represents the similarity (model similarity) of the decarburization oxygen efficiency model formula of the charge of the past charge in the middle of the blowing process with respect to the past charge i at the time of sampling during the blowing process. In the equation (11), the parameter p _i and the parameter q _i indicate the setting parameter p and the setting parameter q calculated for the past charge i, and are stored in the parameter DB 20c.

The parameter C _s , the parameter dC _s /dO ₂ , and the parameter α _s are respectively the carbon concentration, the decarburization oxygen efficiency and the agitation gas influence coefficient of the molten steel in the charge during the blowing process, and are corrected by the model parameters by using the operational performance information. The process of step S2 in the process is calculated by the same process. If the value d _i is 0, the information of the molten steel analysis of the charge during the blowing process completely satisfies the decarburization efficiency model formula of the past charge i. Further, the term in the formula of the difference value ε(i) may be weighted and added to the formula of the value d _i . Thereby, the process of step S14 is completed, and the oxygen supply amount calculation process advances to the process of step S15.

In the process of step S15, the previous process weight calculation unit 33a substitutes the model similarity d _i calculated by the process of step S14 into the following equation (12), thereby calculating the process selected by the process of step S13. The weights of the N past charges, w _i (i = 1 to N). Here, the parameter d _max in the formula (12) means the maximum value of d _i (i=1 to N). Thereby, the process of step S15 is completed, and the oxygen supply amount calculation process advances to the process of step S16.

In the process of the step S16, the model parameter generating unit 33b in the blowing process calculates the setting parameter p and the setting parameter q of the charge in the middle of the blowing process by the following equation (13). Then, the model formula calculation unit 34 calculates the decarburization efficiency by the decarburization efficiency model formula using the calculated setting parameter p and the setting parameter q. Thereby, the process of step S16 is completed, and the oxygen supply amount calculation process proceeds to the process of step S17.

In the process of the step S17, the oxygen supply amount calculation unit 33c calculates the oxygen supply amount (necessary oxygen supply amount) required after the sampling time in the middle of the blowing process, using the decarburization efficiency calculated by the process of step S16. The calculation result is output to the control terminal unit 10 and the display device 50. Here, the reciprocal of the decarburization efficiency is equal to the amount of oxygen per unit of molten steel (Nm ³ /ton) required for the carbon concentration change (decrease) of 1%, so as long as the carbon concentration in the molten steel from the blowing process is to the target By integrating the reciprocal value of the decarburization efficiency until the carbon concentration, the amount of oxygen (per unit molten steel) required to achieve the target carbon concentration in the molten steel can be calculated.

Specifically, the oxygen supply amount calculation unit 33c reads the predetermined agitation gas flow rate of the charge in the middle of the blowing process from the work DB 20a. In the present embodiment, as shown in Fig. 7, the predetermined agitation gas flow rate is set in each section determined by the cumulative oxygen supply amount (the oxygen supply integrated value of oxygen supply completion). Here, V _os refers to the cumulative oxygen supply amount at the time of sampling during the blowing process. Further, in FIG. 7, the way in the blowing process the molten steel after analysis, the gas flow from the unit was stirred V _b 3 is changed to V _b 4. When the unit stirring gas flow rate is changed during the blowing process as described above, the necessary oxygen supply amount may be calculated as follows.

First, the oxygen supply amount calculation unit 33c calculates the carbon concentration C ₃ in the molten steel when the cumulative oxygen supply amount is V _o 3 using the influence coefficient α _s , the set parameter p, and the set parameter q, and the influence coefficient α _s is utilized. The unit stirring gas flow rate V _b 3 and the equation (2) at the sampling point during the blowing process are calculated, and the setting parameter p and the setting parameter q are calculated by the processing of step S16. The carbon concentration C ₃ in the molten steel can be calculated by the following formula (14). Further, the parameter Y in the formula (14) can be expressed by the formula (15) shown below. Further, the oxygen supply amount calculation unit 33c calculates the influence coefficient α ₄ using the unit agitation gas flow rate V _b 4 and the equation (2), and calculates the logarithm equation (1) using the influence coefficient α ₄ , the set parameter p, and the set parameter q. The inverse value of the decarburization efficiency model formula shown is the value obtained by integrating the carbon concentration C ₃ to the target carbon concentration C _e in the molten steel.

The value is the amount of oxygen per unit of molten steel required to reduce the carbon concentration C in the molten steel from the carbon concentration C ₃ in the molten steel to the target carbon concentration C _e , and thus by multiplying the value by melting The weight of the steel can be calculated as the necessary amount of oxygen ΔO ₂ ^f . The amount of oxygen required to finally reduce the carbon concentration C in the molten steel from the carbon concentration C ₃ in the molten steel to the target carbon concentration C _e is (ΔO ₂ + ΔO ₂ ^f ). In the present embodiment, an example has been described in which the flow rate per unit agitation gas is changed only once after the sampling in the middle of the blowing process. However, when the number of changes is repeated a plurality of times, the calculation may be performed by the same process. Furthermore, the above-mentioned integral calculation can be performed by an iterative calculation or by an analytical method. Thereby, the process of step S17 is completed, and a series of oxygen supply amount calculation process is completed.

As is apparent from the above description, the control device 30 of the converter blowing apparatus according to the embodiment of the present invention sets the setting parameters of the decarburization efficiency model formula by the flow rate and component concentration of the exhaust gas. The decarburization efficiency is calculated with high accuracy in the change of the transition of the blowing treatment reaction. Moreover, the control device 30 is off The agitation gas flow rate is added to the variable of the carbon-oxygen efficiency model formula, so that the influence of the change in the agitation gas flow rate during the blowing process is reflected to the decarburization oxygen efficiency model formula, so that the decarburization oxygen efficiency can be calculated with high precision. Thereby, the decarburization efficiency can be calculated with high precision, and the carbon concentration in the molten steel at the end of the blowing process can be accurately controlled to the target carbon concentration.

[Examples]

The invention is applied to the converter offline performance data to verify its accuracy. The necessary oxygen supply amount from the carbon concentration in the molten steel to the target carbon concentration at the time of sampling at the time of sampling during the blowing process is calculated for 100 or more charge materials, and compared with the actual oxygen supply amount. As a result, it has been confirmed that the error of the required oxygen supply amount can be reduced by an average of 50% or more as compared with the prior art (the technique of fixing the model parameters in units of the operation group).

[Industrial availability]

The present invention can be applied to a process of controlling the oxygen supply amount of the charge after sampling at the time of the blowing process so that the carbon concentration in the molten steel at the end of the blowing process reaches the target carbon concentration.

10‧‧‧Control terminal

20‧‧‧Database Server (DB Server)

20a‧‧‧Working database (job DB)

20b‧‧‧Main Information Database (Main Information DB)

20c‧‧‧Parameter database (parameter DB)

30‧‧‧Control device

40‧‧‧ Input device

50‧‧‧ display device

100‧‧‧ converter

101‧‧‧Fused steel

102‧‧‧ spray gun

103‧‧‧ slag

104‧‧‧ catheter

105‧‧‧Exhaust detection department

106‧‧‧Exhaust flowmeter

107‧‧‧Ventinel

108‧‧‧ Flowmeter

Claims (4)

A control device for a converter blowing device controls the oxygen supply amount of the charge after the sampling point in the middle of the blowing process, so that the carbon concentration in the molten steel at the end of the blowing process reaches the target carbon concentration, and the converter blows The control device of the device is characterized by comprising: a model formula calculation unit that calculates the decarburization efficiency by using a model formula that sets at least the carbon concentration and the agitation gas flow rate in the molten steel as input variables, and sets the decarburization efficiency to The output variable has one or more setting parameters, and the model parameter correcting unit uses the carbon concentration in the molten steel, the flow rate of the exhaust gas, and the row in the plurality of past charges that have been completed during the blowing process. At least one of the set parameters is corrected for the component concentration of the gas, the carbon concentration in the molten steel at the end of the blowing process, the flow rate of the exhaust gas, and the component concentration of the exhaust gas; the previous processing weight calculation unit is based on the blowing process The difference between the working conditions of the plurality of past charges and the working conditions of the charge during the blowing process, and the relatives of the charge during the blowing process The similarity of the model formula of the past charge at the sampling point in the middle of the blowing process is calculated, and the weight of each of the past charges is calculated; and the model parameter generating unit during the blowing process uses the setting of each of the past charges corrected by the model parameter correcting unit. The parameter and the weight of each of the past charge calculated by the previous processing weight calculation unit, the setting parameter of the charge during the blowing process is calculated, and the oxygen supply amount calculation unit calculates the blowing process by the decarburization efficiency. The amount of oxygen supplied to the charge during the blowing process after the sampling time on the way, the decarburization efficiency is The model formula calculation unit calculates the carbon concentration in the molten steel measured at the sampling point in the middle of the blowing process, the target carbon concentration, and the setting parameters calculated by the model parameter generating unit in the blowing process. The control device for a converter blowing apparatus according to claim 1, wherein the model parameter correcting unit corrects the setting parameter so that the carbon concentration in the molten steel measured at the point of sampling during the blowing process is When the model formula is established, the difference in carbon concentration in the molten steel at the time of sampling in the middle of the blowing process, the carbon concentration in the molten steel measured at the end of the blowing process, and the blowing process in which the model formula is established are completed. The difference in the carbon concentration in the molten steel and the weighted squared sum of the differences between the set parameters and the standard values are minimized. The control device for a converter blowing device according to the first or second aspect of the invention, wherein the past processing weight calculation unit is a unit melting before sampling at the end of the blowing process and immediately before the end of the blowing process. The agitating gas flow rate of the steel weight is included in the operating conditions. A control method for a converter blowing apparatus, which controls an oxygen supply amount of a charge after a sampling point in a blowing process, so that a carbon concentration in the molten steel at the end of the blowing process reaches a target carbon concentration, and the converter blows The control method of the apparatus is characterized by comprising: a correction step of using a carbon concentration in the molten steel, a flow rate of the exhaust gas, and a composition of the exhaust gas at a point of sampling at the time of the blowing process for the plurality of past charges that have been completed in the blowing process At least one setting parameter of the model formula is corrected for the concentration and the carbon concentration in the molten steel at the end of the blowing treatment, the flow rate of the exhaust gas, and the concentration of the exhaust gas, the model formula at least the carbon concentration and the agitation in the molten steel. The gas flow rate is set as an input variable, and the decarburization oxygen efficiency is set as an output variable; the weight calculation step is based on a difference between the operating conditions of the plurality of past charges that have been completed by the blowing process and the operating conditions of the charge during the blowing process, and Calculating the weight of each past charge relative to the model formula of the past charge in the middle of the blowing process during the blowing process; the parameter calculation step, using the past charge corrected in the correction step The setting parameter and the weight of each of the past charge calculated in the weight calculation step, the setting parameter of the charge during the blowing process is calculated, and the decarburization efficiency is used to calculate the blowing after the sampling point in the middle of the blowing process The amount of oxygen supplied to the charge during the refining process, and the decarburization efficiency is the melting measured at the point of sampling during the blowing process. The carbon concentration in the steel, the target carbon concentration, and the set parameters calculated in the parameter calculation step are calculated based on the model formula.