JP5822053B2 - Control device and control method for converter blowing equipment - Google Patents

Description

  The present invention relates to a control device and a control method for a converter blowing equipment that controls the amount of acid sent to the charge after the sampling point during the blowing process so that the carbon concentration in the molten steel at the end of the blowing process becomes the target carbon concentration. .

  In the converter blowing equipment used at steelworks, the components and temperature of the molten steel at the end of the blowing process are specified by removing impurities in the molten steel and raising the temperature by blowing the oxygen into the molten steel. Control is performed so as to be within the specified range. However, during the blow smelting treatment, the oxidation reaction in the molten steel becomes intense and the molten steel becomes high temperature, so it is difficult to measure the components and temperature of the molten steel every moment.

  Therefore, in actual operation, the carbon concentration in the molten steel at the time of sampling is estimated from the component analysis results of the sampled molten steel during the blowing process, and the molten steel is estimated from the estimated carbon concentration in the molten steel and the decarbonation efficiency model formula. In order to keep the components and temperature within the specified range, the amount of acid sent after the sampling time (hereinafter referred to as the required amount of acid sent) is calculated. The decarbonation efficiency model equation is an equation for calculating the decarbonation efficiency from the carbon concentration in the molten steel. The decarbonation efficiency means the amount of carbon that has gone out of the converter per unit oxygen amount blown into the converter. In general, when the carbon concentration in molten steel is high, the decarbonation efficiency increases.

  By the way, the decarbonation efficiency model equation has a setting parameter. During operation, the value of the setting parameter is changed in accordance with the operation conditions, and the decarbonization efficiency model equation is changed from the changed decarbonation efficiency model equation. Carbon dioxide efficiency is calculated. However, the relationship between the carbon concentration in molten steel and the decarbonation efficiency represented by the decarbonation efficiency model equation varies in a complex manner not only due to operating conditions but also due to various factors including time changes and seasonal changes. For this reason, it is generally difficult to calculate the decarbonation efficiency with high accuracy by appropriately changing the setting parameters of the decarbonation efficiency model formula.

  Against this background, a method for appropriately setting the setting parameters of the decarbonation efficiency model formula has been proposed. Specifically, in Patent Document 1, a past charge that is similar in operating condition to the next charge is selected, and the blow rate calculated from the carbon concentration in the molten steel during the blowing process of the selected past charge and the decarbonation efficiency model equation is selected. A method is described in which the setting parameters of the decarbonation efficiency model formula are determined so that the total value of the error between the carbon concentration in the molten steel at the end of the smelting process and the actual value is minimized. Patent Document 2 describes a method for determining the maximum decarbonation efficiency and the decarbonization efficiency reduction coefficient, which are setting parameters of the decarbonation efficiency model formula, by the regression equation of the operating conditions. It is shown that the use of exhaust gas measurement information is effective for the determination.

JP 2010-7150 A JP 2012-1117090 A

  However, the method described in Patent Document 1 determines the setting parameter of the decarbonation efficiency model equation using only the operating conditions and the component analysis values of the sampled molten steel. For this reason, the change in the transition of the blowing process reaction caused by various disturbances and unmeasured information cannot be taken into account, and there has been a limit to improving accuracy. In addition, as said disturbance and unmeasured information, the component of the raw material thrown into molten steel, a yield, a measurement error, etc. can be illustrated. Further, as one index for grasping the change in transition of the blowing process reaction in real time, there are an exhaust gas flow rate and a component analysis value. However, Patent Document 1 does not mention use of such information.

  On the other hand, in the method described in Patent Document 2, the change in the transition of the blowing treatment reaction is taken into account by including the amount of oxygen stored in the furnace calculated from the exhaust gas measurement information in the explanatory variable of the primary regression equation. However, it is difficult to accurately express the setting parameter of the decarbonation efficiency model expressed by a non-linear mathematical expression using a linear regression equation. For this reason, according to the method described in Patent Document 2, there is a possibility that the calculation accuracy of the decarbonation efficiency by the decarbonation efficiency model equation is lowered.

  Although it may be possible to express the set parameters with high accuracy by adding processing to the exhaust gas measurement information, Patent Document 2 does not have a specific description regarding the processing method of the exhaust gas measurement information. Further, in order to perform regression calculation, it is necessary to calculate in advance the optimum maximum decarbonation efficiency and decarbonation efficiency reduction coefficient for the past charge, but Patent Document 2 relates to the calculation method. There is no specific description.

  Furthermore, the value of the setting parameter of the decarbonation efficiency model formula does not necessarily change during the blowing process for one charge. As a result of data analysis by the inventors, especially when the flow rate of the stirring gas blown into the converter changes during charging, the setting parameter of the decarbonation efficiency model equation changes under the influence of the flow rate of the stirring gas. Has been obtained. 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 for one charge. For this reason, according to the methods described in Patent Documents 1 and 2, there is a possibility that the calculation accuracy of the decarbonation efficiency by the decarbonation efficiency model equation is lowered.

  The present invention has been made in order to solve the above-described problems, and by accurately calculating the decarbonation efficiency, the carbon concentration in the molten steel at the end of the blowing process can be accurately controlled to the target carbon concentration. An object of the present invention is to provide a control device and a control method for a simple converter blowing facility.

  In order to solve the above-described problems and achieve the object, the control device for the converter blowing equipment according to the present invention performs sampling during the blowing process so that the carbon concentration in the molten steel at the end of the blowing process becomes the target carbon concentration. A control device for converter blowing equipment that controls the amount of acid sent after charging, wherein at least one carbon concentration in molten steel and a stirring gas flow rate are input variables, and decarbonation efficiency is an output variable. A model formula calculation unit that calculates decarbonation efficiency using a model formula having setting parameters, and a plurality of past charges that have been subjected to the blowing process, and in the molten steel at the sampling point during the blowing process and at the end of the blowing process A model parameter correction unit that corrects at least one of the setting parameters using the carbon concentration, the exhaust gas flow rate, and the exhaust gas component concentration, and a plurality of past charges that have been blown. Calculate the weight of each past charge based on the difference between the operating condition and the operating condition of the charge during the blowing process and the similarity of the charge during the blowing process to the model formula of the past charge at the sampling point during the blowing process Using the past processing weight calculation unit, the setting parameter of each past charge corrected by the model parameter correction unit, and the weight of each past charge calculated by the past processing weight calculation unit, Using the model parameter generating unit for calculating setting parameters, the carbon concentration in the molten steel measured at the sampling point during the blowing process, the target carbon concentration, and the setting parameters calculated by the model parameter generating unit during blowing Using the decarbonation efficiency calculated by the model formula calculation unit, And oxygen-flow amount calculating unit which calculates the oxygen-flow amount of smelting of being processed charge, characterized in that it comprises a.

  The control device for a converter blowing facility according to the present invention is the above-described invention, wherein the model parameter correcting unit is in the middle of the blowing process that establishes the carbon concentration in the molten steel and the model formula measured at the sampling point during the blowing process. Difference between carbon concentration in molten steel at the time of sampling, difference between carbon concentration in molten steel measured at the end of the blowing process and carbon concentration in the molten steel at the end of the blowing process that establishes the above model formula, and standard of each setting parameter The setting parameter is modified so as to minimize the weighted square sum of the difference from the value.

  In the above invention, the control unit for the converter blowing equipment according to the present invention is characterized in that the past processing weight calculation unit calculates the stirring gas flow rate per unit molten steel weight at the sampling time during the blowing process and immediately before the end of the blowing process. It is included in the operating conditions.

  In order to solve the above-described problems and achieve the object, the method for controlling a converter blowing facility according to the present invention is a sampling in the middle of the blowing process so that the carbon concentration in the molten steel at the end of the blowing process becomes the target carbon concentration. This is a method for controlling converter blowing equipment that controls the amount of acid sent to the charge after the time point, and for a plurality of past charges that have been blown, the molten steel is being sampled during the blowing process and at the end of the blowing process. Using the carbon concentration, the exhaust gas flow rate, and the exhaust gas component concentration, at least one of the setting parameters of the model equation with at least the carbon concentration in molten steel and the stirring gas flow rate as input variables and decarbonation efficiency as the output variable is corrected. The difference between the correction step, the operating conditions of multiple past charges that have been blown, and the operating conditions of the charges that are being blown, and the past A weight calculation step for calculating the weight of each past charge based on the similarity of the charge in the middle of the blowing process with respect to the model formula, and a setting parameter for each past charge corrected in the correction step and the weight calculation step Using the calculated weight of each past charge, a parameter calculation step for calculating a setting parameter for the charge during the blowing process, a carbon concentration in the molten steel measured at the sampling point during the blowing process, a target carbon concentration, and Using the decarbonation efficiency calculated from the model formula using the setting parameter calculated in the parameter calculation step, the amount of acid sent in the charge during the blowing process after the sampling point during the blowing process is calculated. And a step.

  According to the control device and the control method for the converter blowing equipment according to the present invention, the carbon concentration in the molten steel at the end of the blowing process is accurately controlled to the target carbon concentration by accurately calculating the decarbonation efficiency. Can do.

FIG. 1 is a schematic diagram illustrating a configuration of a converter blowing equipment and a control system thereof to which a control device and a control method for a converter blowing equipment according to an embodiment of the present invention are applied. FIG. 2 is a block diagram showing a configuration of the control device shown in FIG. FIG. 3 is a diagram illustrating a function example of the influence coefficient of the stirring gas. FIG. 4 is a diagram showing the relationship between carbon concentration in molten steel and decarbonation efficiency. FIG. 5 is a flowchart showing a flow of model parameter correction processing according to an embodiment of the present invention. FIG. 6 is a flowchart showing the flow of the amount of oxygen supply calculation process according to the embodiment of the present invention. FIG. 7 is a diagram showing an example of the relationship between the unit agitation gas flow rate and the integrated acid supply amount.

  Hereinafter, with reference to drawings, a control device and a control method of a converter blowing equipment which is one embodiment of the present invention are explained.

[Configuration of converter blowing equipment]
First, with reference to FIG. 1, the structure of the converter blowing equipment to which the control apparatus and control method of the converter blowing equipment which are one Embodiment of this invention are applied is demonstrated.

  FIG. 1 is a schematic diagram illustrating a configuration of a converter blowing equipment and a control system thereof to which a control device and a control method for a converter blowing equipment according to an embodiment of the present invention are applied. As shown in FIG. 1, in a converter blowing equipment to which a control device and a control method for a converter blowing equipment according to an embodiment of the present invention are applied, a lance 102 is disposed on a molten steel 101 in the converter 100. Then, high-pressure oxygen is ejected from the tip of the lance 102 toward the molten steel 101. Impurity components in the molten steel 101 are oxidized by the high-pressure oxygen ejected from the lance 102 and taken into the slag 103 (blowing process).

An exhaust gas smoke duct 104 is installed in the upper part of the converter 100, and the exhaust gas components (for example, CO, CO ₂ , O ₂ , N, etc.) discharged during the blowing process are placed inside the duct 104. ₂ , H ₂ O, Ar, and the like) and an exhaust gas flow meter 106 for measuring the flow rate of the exhaust gas. The flow rate of the exhaust gas is obtained by calculating the differential pressure upstream and downstream of the venturi pipe or the orifice and calculating based on the measured value. Since the exhaust gas is a gas and its volume changes depending on temperature and pressure, the calculated value is converted into a gas flow rate in a standard state (for example, temperature 0 ° C., pressure 1 atmosphere).

  Ar gas, which is an inert gas, is blown into the molten steel 101 in the converter 100 through a vent hole 107 formed at the bottom of the converter 100, and the molten steel 101 is agitated by the Ar gas. Reaction with the molten steel 101 is promoted. The flow rate of Ar gas (stirring gas flow rate) blown into the molten steel 101 is measured using a flow meter 108. The temperature and components of the molten steel 101 are measured once during the blowing process, and the supply amount (acid supply amount) and supply rate (acid supply rate) of high-pressure oxygen, the stirring gas flow rate, and the like are determined based on the measured information. Further, immediately before the start of the blowing process and after the end of the blowing process, the temperature and components of the molten steel 101 are analyzed. Generally, the operation amount of the blowing process is set once before the start of the blowing process, and is corrected after obtaining the measured values of the temperature and components of the molten steel during the blowing process. The present invention relates to the latter determination of the amount of acid.

[Configuration of control system]
Next, with reference to FIG. 1, the structure of the control system of the converter blowing equipment to which the control apparatus and control method of the converter blowing equipment which are one Embodiment of this invention is applied is demonstrated.

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

  The control terminal 10 is configured by an information processing apparatus such as a personal computer or a workstation. The control terminal 10 controls the acid supply amount, the acid supply speed, the stirring gas flow rate, the height of the lance 102, and the auxiliary raw material input amount so that the component concentration of the molten steel 101 falls within a desired range, and the oxygen supply amount. The data of the actual values of the feed rate, the stirring gas flow rate, the lance height, and the input amount of the auxiliary raw material are collected as the actual operation amount.

  The DB server 20 includes an operation database (operation DB) 20a, a master information database (master information DB) 20b, and a parameter database (parameter DB) 20c.

  The operation DB 20a stores time-series and non-time-series operation result information related to past charge for which the blowing process has been completed, and time-series and non-time-series operation result information related to the charge during the blowing process. Time-series operation result information includes data on the operation amount results (time-series information on the acid supply amount, acid supply speed, stirring gas flow rate, lance height, and auxiliary material input amount), and data on operation amount plan (scheduled acid supply rate). Data, time-series information on the amount, planned acid feed rate, planned stirring gas flow rate, planned lance height, and planned auxiliary material input amount), and data on exhaust gas performance (time-series information on exhaust gas component concentration and flow rate). Operation results information other than time series includes specification information (hot metal information (steel type), production specifications (target carbon concentration, target temperature)), and data related to the operation amount plan (planned total acid feed, planned total amount of auxiliary raw materials input, Planned agitation gas total amount), the actual value of the total amount of acid sent, and data on the component concentration and temperature of the molten steel before and after the blowing process and during the blowing process.

  The master information DB 20b stores data such as physical constants, threshold values, setting parameters, and the like necessary for executing a model parameter correction process and an acid supply amount calculation process, which will be described later.

  The parameter DB 20c stores setting parameters of the decarbonation efficiency model formula corrected for each past charge in a model parameter correction process described later.

  The control device 30 uses the actual operation amount collected by the control terminal 10 and the exhaust gas component concentration and flow rate (exhaust gas results) measured by the exhaust gas detection unit 105 and the exhaust gas flowmeter 106 as blowing information during blowing. Based on the medium charge information, the required amount of acid delivery is calculated, and the calculation result is output to the control terminal 10 and the display device 50. The detailed configuration of the control device 30 will be described later.

  The input device 40 is configured by an input device such as a keyboard and a mouse pointer, and is operated when inputting various information related to processing to be described later. The display device 50 is configured by a display device such as a CRT or a liquid crystal display, and displays various processing results of the control device 30.

[Configuration of control device]
Next, the configuration of the control device 30 will be described with reference to FIG.

  FIG. 2 is a block diagram illustrating a configuration of the 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 / 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 an arithmetic processing device in the control device 30 executing a computer program. 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, an in-blow model parameter generation unit 33b, and an oxygen delivery amount calculation unit 33c. The functions of these units will be described later.

  The control device 30 having such a configuration calculates the decarbonation efficiency with high accuracy by executing the following model parameter correction process and oxygen delivery amount calculation process, and the carbon concentration in the molten steel at the end of the blowing process Is accurately controlled to the target carbon concentration. Hereinafter, the operation of the control device 30 when executing the model parameter correction process and the oxygen supply amount calculation process will be described.

[Model parameter correction processing]
First, the flow of model parameter correction processing according to an embodiment of the present invention will be described with reference to FIGS.

  In the control device 30 according to the embodiment of the present invention, when the model parameter correction unit 32a acquires the operation result information of the charge for which the blowing process has been completed via the input / output unit 31, the decarboxylation used in the operation. Modify the setting parameters of the efficiency model formula to match the operation results information.

In the present embodiment, the decarbonation efficiency model formula is described by a non-linear function or an interval linear function, and is represented by, for example, the following formulas (1) and (2). Equation (1) below shows the amount of decrease in carbon concentration in molten steel relative to the basic unit of acid delivery (Nm ³ / ton: acid delivery [Nm ³ ] divided by the weight of molten steel to be treated [ton]) (% ). In Equation (1), parameter C is the carbon concentration in the molten steel, and k, q, and p are set parameters. The parameter α is an influence coefficient of the stirring gas (Ar gas). As shown in the following formula (2), the basic unit of stirring gas flow rate (Nm ³ / Hr / ton: dividing the stirring gas flow rate by the molten steel weight to be processed) The value is determined by _Vb . The value of the agitation gas influence coefficient α may be given in a table or a continuous function. An example of the function of the stirring gas influence coefficient α is shown in FIG. In this case, the model parameter correction unit 32a reads function setting parameters from the master information DB 20b.

FIG. 4 shows a graph of Equation (1) when the stirring gas influence coefficient α is constant. As shown in FIG. 4, the decarbonation efficiency dC / dO ₂ increases as the value of the carbon concentration C in the molten steel increases. However, the decarbonation efficiency dC / dO ₂ does not exceed the set parameter k. The reason for this is that the amount of oxygen that is blown in the state in which the carbon concentration C in the molten steel is sufficient is more restrictive of the amount of decarburization. Further, when the carbon concentration C in the molten steel is lower than the setting parameter q, the decarbonation efficiency becomes zero, meaning that the decarburization reaction itself does not occur unless the carbon concentration C in the molten steel becomes a value equal to or higher than the setting parameter q. doing. Further, when the setting parameter p is changed, the decarburization reaction rate changes as shown in FIG.

  In the decarbonation efficiency model formula shown in the mathematical formula (1), the setting parameter p is multiplied by the stirring gas influence coefficient α. Therefore, when the value of the stirring gas influence coefficient α decreases, the decarburization reaction rate increases. The present invention aims to improve model accuracy by introducing the stirring gas influence coefficient α into the decarbonation efficiency model. There are three setting parameters, k, p, and q, as described above. Which setting parameter is to be corrected for each charge may be determined according to the characteristics of the target converter blowing equipment. In this embodiment, the value of the setting parameter k is fixed and only the setting parameters p and q are corrected. That is, the standard values of the setting parameters p and q are P and Q, the correction amounts are δp and δq, and the standard values P and Q are corrected in the sum form shown in the following equations (3) and (4).

  Hereinafter, with reference to FIG. 5, the flow of the model parameter correction process according to the embodiment of the present invention will be described in detail.

  FIG. 5 is a flowchart showing a flow of model parameter correction processing according to an embodiment of the present invention. The flowchart shown in FIG. 5 starts at the timing when the blowing process is completed, and the model parameter correction process proceeds to the process of step S1.

  In the process of step S <b> 1, the model parameter correction unit 32 a acquires operation result information of the charge for which the blowing process has been completed via the input / output unit 31. Thereby, the process of step S1 is completed and a model parameter correction process progresses to the process of step S2.

In the process of step S2, the model parameter correction unit 32a uses the operation result information acquired in the process of step S1, and the carbon concentration in the molten steel (analyzed value) C _s , C _e , decarbonation efficiency dC _s / dO ₂ , dC _e / dO ₂ , and stirring gas influence coefficients α _s and α _e are calculated.

Specifically, the blow being processed sampling point and blowing process at the end of the molten steel carbon concentration respectively C _s, when the C _e, blowing being processed sampling point and blowing process at the end of decarboxylation oxygen efficiency dC _s / dO ₂ and dC _e / dO ₂ can be calculated according to the following formula (5) using the exhaust gas performance at the time of sampling during the blowing process and at the end of blowing.

However, it is assumed that the time delay associated with the analysis of the exhaust gas flow rate and component concentration has been taken into account. Further, blowing being processed sampling point and blowing process at the end of the stirring gas effect coefficient alpha _s, alpha _e respectively, formulas stirring gas flow per unit V _b during blowing process middle sampling point and blowing process ends ( It can be calculated by substituting in 2). Thereby, the process of step S2 is completed, and the model parameter correction process proceeds to the process of step S3.

Here, in Equation (5), the parameters V _ex , V _o , and ρ _c are the exhaust gas flow rate [Nm ³ / Hr], the acid feed flow rate [Nm ³ / Hr], the CO gas in the exhaust gas, and The sum of the concentration of CO ₂ gas [%] is shown. If these measured values contain a lot of noise, a value obtained by adding a filtering process such as a moving average value may be substituted, or a value obtained by correcting a bias error may be substituted.

  In the process of step S3, the model parameter correcting unit 32a uses the value calculated in the process of step S2 to perform the decalcification calculated from the decarbonation efficiency model equation at the sampling point during the blowing process and at the end of the blowing process. The setting parameters p and q are corrected so that the error with respect to the actual value of the carbonic acid efficiency becomes as small as possible. However, when the setting parameters p and q are corrected, the setting parameters p and q are not greatly deviated from the standard values P and Q. In the present embodiment, the setting parameters p and q are corrected by using an error function J shown in the following formula (6) for simplicity of calculation processing.

Here, the first term and the second term in Equation (6) indicate the decarbonation efficiency error calculated from the decarbonation efficiency model equation at the sampling time during the blowing process and at the end of the blowing process, respectively. Substituting the processing result of step S2 into Equation (1), and taking the difference between both sides of the equation for calculating the shift and the logarithm of both sides are the first and second terms of Equation (6). Further, the third and fourth terms of the formula (6) are added to prevent the setting parameters p and q from deviating greatly from the standard values P and Q. The parameters σ _s , σ _e , σ _p , and σ _q in the equation (6) are values set by the user of this apparatus. If the parameter value is set small, the denominator error of the corresponding term in the equation (6) is reduced. Can be small. As an example of the parameter setting method, the denominator value of each term of Equation (6) is calculated for a large number of past charges, the standard deviation for each is calculated, and these values are used as the parameter setting values. There is a way to do it.

  In this process, the correction amounts δp and δq of the setting parameters p and q are determined so as to minimize the error function J. Since the error function J is a quadratic polynomial of the correction amounts δp and δq, the minimum solution is It can be calculated by inverse matrix calculation. Specifically, first, the error function J is expressed by the following formula (7). Here, in Equation (7), x is a two-dimensional vertical vector whose elements are correction amounts δp and δq, D is a 2 × 2 constant matrix, E is a two-dimensional constant vertical vector, and F is a constant scalar term. T on the right shoulder of the vector means transposition.

  When the error function J is expressed by the above equation (7), the error function J takes the minimum value when the following equation (8) holds.

  When this formula (8) is modified, the following formula (9) is obtained.

  Since the correction amounts δp and δq that minimize the error function J are calculated by this calculation, the setting parameters p and q are corrected by using the equations (3) and (4). Even when an error function J different from Equation (7) is used, correction calculation of the setting parameters p and q is possible by using a 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 correction unit 32a stores the setting parameters p and q corrected by the process of step S3 via the input / output unit 31 in the parameter DB 20c. Thereby, the process of step S4 is completed and a series of model parameter correction process is complete | finished.

[Oxidation amount calculation processing]
Next, with reference to FIG. 6, FIG. 7, the flow of the amount calculation process of oxygen transmission which is one Embodiment of this invention is demonstrated.

  FIG. 6 is a flowchart showing the flow of the amount of oxygen supply calculation process according to the embodiment of the present invention. The flowchart shown in FIG. 6 starts at the timing when the control device 30 acquires the molten steel analysis result at the time of sampling during 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 process weight calculation unit 33a reads the past performance operation result information and various set values from the operation DB 20a and the master information DB 20b, respectively. Thereby, the process of step S11 is completed, and the acid amount calculation process proceeds to the process of step S12.

  In the process of step S12, the past process weight calculation unit 33a selects only the same type of charge as the charge during the blowing process from the past charge. However, the same type of charge means that, for example, the following points are the same. Thereby, the process of step S12 is completed, and the acid amount calculation process proceeds to the process of step S13.

(1) Process purpose is the same: any one of de-P blowing, de-C blowing, and normal blowing (de-P blowing and de-C blowing are performed simultaneously) (2) target carbon concentration and target at the end point The temperature belongs to the same range (the threshold value of the range is stored in the master information DB 20b)
(3) The blowing process execution date is within the specified number of days from now

  In the process of step S13, the past process weight calculation unit 33a calculates a difference value between the operation condition of the past charge selected in the process of step S12 and the operation condition of the charge in the middle of the blowing process. The past charges are sorted in ascending order of the difference value, and the specified number N of past charges are selected from the head of the sorted past charges. The difference value can be calculated by, for example, the following formula (10). Ε (i) shown in the following formula (10) indicates the difference between the operation condition of the i-th past charge and the charge operation condition during the blowing process, and the weighted sum of the squares of the difference of the operation conditions It is constituted by.

In Expression (10), the parameter x _p (p = 1 to n) is the p-th operation result information of the charge during the blowing process (measured information of the molten steel before the blowing process, molten steel at the time of sampling during the blowing process) Analytical value, manipulated variable at the time of sampling during blowing process (stirring gas flow rate, etc.) and scheduled operation amount at the end of blowing process (stirring gas flow rate, etc.)), parameters x ′ _{i, p} are the i th past charge p-th operation result information (measurement information of molten steel before blowing process, analysis value of molten steel at the time of sampling during blowing process, operation amount (flow rate of stirring gas, etc.) at the time of sampling during blowing process, and at the end of blowing process) The actual operation amount (using the stirring gas flow rate, etc.) is used, and the parameter _Wp represents a weighting factor. The smaller the value of ε (i), the more the past charge of the operation condition is similar to the operation condition of the charge during the blowing process. Thereby, the process of step S13 is completed, and the amount calculation process of oxygen supply progresses to the process of step S14.

In the process of step S14, the past process weight calculation unit 33a calculates values d _i (i = 1 to N) shown in the following formula (11) for each of the N past charges selected in the process of step S13. calculate. The value d _i indicates the similarity (model similarity) of the charge during the blowing process with respect to the decarbonation efficiency model formula of the past charge i at the time of sampling during the blowing process. In equation (11), parameters p _i and q _i indicate setting parameters p and q calculated for the past charge i, and are stored in the parameter DB 20c.

The parameters C _s , dC _s / dO ₂ , and α _s are the carbon concentration in the molten steel, the decarbonization efficiency, and the agitation gas influence coefficient, respectively, in the middle of the blowing process. It is calculated by a process similar to the process. If the value d _i becomes 0, it means that the information at the time of molten steel analysis of the charge during the blowing process completely satisfies the decarbonation efficiency model formula of the past charge i. It is also possible to add a weight to the term in the expression of the difference value ε (i) to the expression of the value d _i . Thereby, the process of step S14 is completed, and the acid amount calculation process proceeds to the process of step S15.

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

  In the process of step S16, the model parameter generating unit 33b during blowing calculates the setting parameters p and q related to the charge during the blowing process using the following formula (13). Then, the model formula calculation unit 34 calculates the decarbonation efficiency from the decarbonation efficiency model formula using the calculated setting parameters p and q. Thereby, the process of step S16 is completed, and the acid amount calculation process proceeds to the process of step S17.

In the process of step S17, the acid supply amount calculation unit 33c calculates the amount of acid (necessary acid supply) required after the sampling point during the blowing process using the decarbonation efficiency calculated by the process of step S16. Then, the calculation result is output to the control terminal 10 and the display device 50. Here, since the reciprocal of decarbonation efficiency is equal to the amount of oxygen per unit molten steel (Nm ³ / ton) required for 1% change (decrease) in the carbon concentration, the target carbon is determined from the carbon concentration in the molten steel during the blowing process. If the inverse value of decarbonation efficiency is integrated to the concentration, the amount of acid transport (per unit molten steel) necessary for the carbon concentration in the molten steel to become the target carbon concentration can be calculated.

Specifically, the acid supply amount calculation unit 33c reads the scheduled stirring gas flow rate of the charge during the blowing process from the operation DB 20a. In this embodiment, as shown in FIG. 7, the planned stirring gas flow rate is set for each section determined by the integrated amount of oxygen (the integrated amount of oxygen that has been acidified). Here, V _OS means the integrated amount of acid fed at the time of sampling during the blowing process. In FIG. 7, the unit agitation gas flow rate after blowing being processed molten steel analysis is changed from V _{b 3} to V _{b 4.} In this way, when the unit agitation gas flow rate is changed during the blowing process, the required amount of acid sent may be calculated as follows.

First, the acid supply amount calculation unit 33c calculates the influence coefficient α _s calculated from the unit agitation gas flow rate V _b 3 and the mathematical expression (2) at the time of sampling during blowing, and the setting parameters p and q calculated by the process of step S16. Is used to calculate the carbon concentration C ₃ in the molten steel when the cumulative amount of acid sent is V _O 3. The molten steel in the carbon concentration C ₃ can be calculated by equation (14) below. The parameter Y in the formula (14) is expressed by the following formula (15). Then, the acid supply amount calculation unit 33c calculates the influence coefficient α ₄ from the unit agitation gas flow rate V _b 4 and the mathematical expression (2), and removes the influence coefficient α ₄ and the setting parameters p and q from the mathematical expression (1). calculating the integrated value of the reciprocal value of the carbonate oxygen efficiency model equation from the molten steel in the carbon concentration C ₃ to the target carbon concentration C _e.

This value is quantity of oxygen per unit of molten steel weight necessary to reduce the molten steel in the carbon concentration C to the target carbon concentration C _e of molten steel in the carbon concentration C _3, need oxygen delta O.D. ₂ by applying a molten steel weight to the value ^f can be calculated. Amount of oxygen required to reduce the carbon concentration C in the molten steel from the final molten steel in the carbon concentration C ₃ to the target carbon concentration C _e becomes ^{_{(ΔO 2 + ΔO 2 f)}} . In the present embodiment, an example in which the unit agitation gas flow rate is changed only once after the sampling time in the middle of the blowing process is shown, but it can be calculated by the same process even when changed a plurality of times. The integral calculation described above may be performed repeatedly or may be calculated analytically. Thereby, the process of step S17 is completed and a series of acid amount calculation processes are completed.

  As is apparent from the above description, the converter 30 of the converter blowing facility according to the embodiment of the present invention sets the setting parameters of the decarbonation efficiency model equation using the flow rate and component concentration of the exhaust gas. Therefore, decarbonation efficiency can be calculated with high accuracy in consideration of changes in the transition of the blowing process reaction. In addition, the controller 30 adds the stirring gas flow rate to the variable of the decarbonation efficiency model equation, and reflects the effect of the change in the stirring gas flow rate during the blowing process on the decarbonation efficiency model equation. Carbon dioxide efficiency can be calculated with high accuracy. Thereby, decarbonation efficiency can be calculated accurately and the carbon concentration in the molten steel at the end of the blowing process can be accurately controlled to the target carbon concentration.

〔Example〕
The present invention was applied to converter offline record data and the accuracy was verified. For 100 or more charges, the required amount of acid sent from the carbon concentration in the molten steel to the target carbon concentration at the time of sampling during the blowing process was calculated and compared with the actual amount of acid sent. As a result, it was confirmed that the error in the required amount of oxygen could be reduced by an average of 50% or more compared to the conventional technique (the model parameter is fixed by the operation group).

  The present invention can be applied to the process of controlling the amount of acid sent to the charge after the sampling point during the blowing process so that the carbon concentration in the molten steel at the end of the blowing process becomes the target carbon concentration.

10 control terminal 20 database server (DB server)
20a Operation database (operation DB)
20b Master information database (master information DB)
20c Parameter database (parameter DB)
DESCRIPTION OF SYMBOLS 30 Control apparatus 31 Input / output part 32 1st process part 32a Model parameter correction part 33 2nd process part 33a Past process weight calculation part 33b Model parameter generation part 33c during blowing process Acid amount calculation part 34 Model formula calculation part 40 Input device DESCRIPTION OF SYMBOLS 50 Display apparatus 100 Converter 101 Molten steel 102 Lance 103 Slag 104 Duct 105 Exhaust gas detection part 106 Exhaust gas flow meter 107 Vent hole 108 Flow meter

Claims (4)

A control device for a converter blowing equipment that controls the amount of acid sent to the charge after sampling during the blowing process so that the carbon concentration in the molten steel at the end of the blowing process becomes the target carbon concentration,
A model formula calculation unit that calculates decarbonation efficiency using a model formula having one or more setting parameters, with at least the carbon concentration in the molten steel and the stirring gas flow rate as input variables and decarbonation efficiency as output variables;
For a plurality of past charges for which the blowing process has been completed, at least one of the setting parameters is determined by using the carbon concentration in the molten steel, the flow rate of the exhaust gas, and the component concentration of the exhaust gas at the sampling point during the blowing process and at the end of the blowing process. A model parameter correction section to be corrected;
Differences between the operating conditions of multiple past charges that have been blown and the operating conditions of charges during the blowing process, and the similarity of charges during the blowing process to the model formula of the past charge at the sampling point during the blowing process A past processing weight calculator for calculating the weight of each past charge based on
Blowing that calculates the setting parameter of the charge during the blowing process using the setting parameter of each past charge corrected by the model parameter correction unit and the weight of each past charge calculated by the past processing weight calculation unit Medium model parameter generator,
Decarbonization efficiency calculated by the model formula calculation unit using the carbon concentration in the molten steel measured at the sampling point during the blowing process, the target carbon concentration, and the setting parameters calculated by the model parameter generation unit during the blowing process. And using an oxygen amount calculation unit for calculating the amount of acid sent during the blowing process after the sampling point during the blowing process,
The control apparatus of the converter blowing equipment characterized by including.   The model parameter correction unit is measured at the end of the blowing process, the difference between the carbon concentration in the molten steel measured at the sampling point during the blowing process and the carbon concentration in the molten steel at the sampling point during the blowing process to establish the model formula. The setting parameter is set to minimize the difference between the carbon concentration in the molten steel and the carbon concentration in the molten steel at the end of the blowing process that establishes the model formula, and the weighted square sum of the difference from the standard value of each setting parameter. The control device for a converter blowing equipment according to claim 1, wherein the control device is modified.   The said past process weight calculation part includes the stirring gas flow rate per unit molten steel weight at the sampling time in the middle of the blowing process and immediately before the end of the blowing process in the operating conditions. Control device for furnace blowing equipment. A control method for a converter blowing equipment that controls the amount of acid sent to the charge after sampling during the blowing process so that the carbon concentration in the molten steel at the end of the blowing process becomes the target carbon concentration,
For a plurality of past charges for which the blowing process has been completed, at least the carbon concentration in the molten steel and the agitation are performed using the carbon concentration in the molten steel, the flow rate of the exhaust gas, and the component concentration of the exhaust gas at the sampling point during the blowing process and at the end of the blowing process A correction step for correcting at least one of the setting parameters of the model formula in which the gas flow rate is an input variable and the decarbonation efficiency is an output variable;
The difference between the operating conditions of multiple past charges after the blowing process and the operating conditions of the charge during the blowing process, A weight calculating step for calculating the weight of each past charge based on
A parameter calculation step for calculating a setting parameter for the charge during the blowing process using the setting parameter for each past charge corrected in the correction step and the weight for each past charge calculated in the weight calculation step;
Using the decarbonation efficiency calculated from the model equation using the carbon concentration in the molten steel measured at the sampling point during the blowing process, the target carbon concentration, and the setting parameters calculated in the parameter calculation step, Calculating the amount of acid sent during the smelting process after the sampling time during the smelting process;
The control method of the converter blowing equipment characterized by including.

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