WO2018012257A1

WO2018012257A1 - Method for estimating phosphorus concentration in molten steel and converter blowing control device

Info

Publication number: WO2018012257A1
Application number: PCT/JP2017/023246
Authority: WO
Inventors: 健岩村; 杉橋　敦史; 政憲沼田; 康介久米
Original assignee: 新日鐵住金株式会社
Priority date: 2016-07-14
Filing date: 2017-06-23
Publication date: 2018-01-18
Also published as: TWI643957B; JP6573035B2; CN108779506B; CN108779506A; KR102065455B1; JPWO2018012257A1; KR20180114919A; TW201812024A

Abstract

[Problem] To estimate the phosphorus concentration in molten steel with high precision when converter blowing is stopped in an operation that uses a multi-refining converter method. [Solution] A method for estimating the phosphorus concentration in molten steel is used in primary refining using a converter that involves an intermediate slag removal process and comprises: a slag level data-acquiring step for acquiring the slag level during a dephosphorizing process; an effluent gas data-acquiring step for acquiring effluent gas components and effluent gas flow during a decarbonization process; a molten steel data-acquiring step for acquiring the molten steel temperature and carbon concentration in the molten steel by sublance measurement during the decarbonization process; and a phosphorus concentration-estimating step for calculating a dephosphorization rate constant using data relating to the slag level, effluent gas components, effluent gas flow, molten steel temperature and carbon concentration as well as operating conditions relating to the dephosphorization process, intermediate slag removal process and decarbonization process, and using the calculated dephosphorization rate constant and the molten pig iron phosphorus concentration at the beginning of the dephosphorization process, estimating the phosphorus concentration in the molten steel during the decarbonization process after the sublance measurement.

Description

Method for estimating phosphorus concentration in molten steel and converter blowing control device

The present invention relates to a method for estimating phosphorus concentration in molten steel and an apparatus for estimating phosphorus concentration in molten steel, which accurately estimate the phosphorus concentration in molten steel at the time of blowing in a converter during operation by a multi-function converter method.

In converter blowing, control of the components in the molten steel at the time of blowing (in particular, control of the phosphorus concentration in the molten steel) is very important for quality control of the steel. In order to control the phosphorus concentration in the molten steel, the amount of oxygen injected, the amount of auxiliary materials such as quick lime or scale, the timing of the auxiliary materials, the top blowing lance height, the top blowing oxygen flow rate, and the bottom blowing gas flow rate Are generally used as manipulated variables. These operation amounts are often determined by information obtained before the start of blowing, such as a target phosphorus concentration, hot metal data, a standard created based on past operation results, and the like.

However, even under similar operating conditions, there was a problem that the reproducibility of the dephosphorization behavior in actual blowing was low and the variation in phosphorus concentration in molten steel at the time of blowing was large. For this reason, it has been difficult to suppress the variation in phosphorus concentration in molten steel at the time of blowing by the blowing by the operation amount determined based only on the information obtained before the start of blowing as described above.

In order to deal with the above problems, a technology that utilizes measured values of exhaust gas components and exhaust gas flow rate obtained sequentially during blowing has been developed. For example, in Patent Document 1 below, the dephosphorization rate constant is estimated using the operating conditions related to blowing and the measured values related to exhaust gas, and the phosphorus concentration in the molten steel during blowing is calculated using the estimated dephosphorization rate constant. An estimation technique is disclosed. Furthermore, in Patent Document 1 below, the estimated phosphorus concentration in molten steel and the target phosphorus concentration in molten steel are compared, and the phosphorus concentration in molten steel is controlled by changing the operating conditions related to blowing based on the comparison result. Techniques to do this are disclosed.

JP 2013-23696 A

In recent years, hot metal pretreatment such as dephosphorization using a converter is generally performed in primary refining. In particular, the development of a technology called the multi-functional converter method (MUlti Refining Converter: MURC) that can consistently perform hot metal pretreatment and decarburization in the same converter in primary refining . Specifically, the MURC charges the hot metal into the converter (first step) and performs hot metal pretreatment including dephosphorization processing by adding flux and blowing oxygen with an upper blowing lance (second step). , The converter is tilted to perform an intermediate waste treatment for exhausting the slag generated in the second step (third step), and thereafter, the decarburization treatment is performed by the converter (fourth step). This is the primary refining operation method. MURC has less heat loss compared to the primary refining operation method in which dephosphorization and decarburization processes are performed in different converters, such as the conventional simple refining process (SRP). Since the lead time is short, it has an advantage of high production efficiency in the steel making process.

In this MURC, the slag generated in the dephosphorization process that is the second process described above is discharged by the intermediate process that is the third process. At this time, depending on the amount of slag generated in the dephosphorization process or the quality of the slag, the amount of slag discharged by the intermediate discharge process differs for each operation.

Phosphorus contained in the hot metal after the intermediate waste treatment is desorbed from the hot metal and taken into the slag by a dephosphorization reaction represented by the following chemical formula (101) that can occur in parallel with the decarburization reaction during the decarburization treatment. On the contrary, it may be detached from the slag and taken back into the hot metal. In the following chemical formula (101), the expression “[substance X]” indicates that the substance X is present in the hot metal, and the expression “(substance Y)” indicates that the substance Y is slag. Indicates that the substance is present inside.

The direction in which the dephosphorylation reaction represented by the chemical formula (101) proceeds varies depending on the amount and components of slag discharged during the intermediate waste treatment (or the amount and components of slag remaining in the converter). To do. That is, the reaction direction and reaction rate of the dephosphorization reaction depend on the amount of slag discharged during the intermediate waste treatment. Therefore, it is considered that the amount of slag discharged during the intermediate waste treatment affects the phosphorus concentration in the molten steel during the decarburization treatment.

In the above-mentioned Patent Document 1, the phosphorus concentration in molten steel is estimated using the operating conditions at the time of converter blowing operation. However, in the said patent document 1, it does not consider about the quantity of the slag discharged | emitted at the time of an intermediate | middle waste process. Considering that the phosphorus concentration in molten steel at the time of decarburization affects the amount of slag discharged at the time of intermediate waste treatment, the technique disclosed in Patent Document 1 described above is used in primary refining with intermediate waste treatment. It is difficult to estimate the phosphorus concentration in molten steel with high accuracy.

Therefore, the present invention has been made in view of the above problems, and the object of the present invention is to accurately estimate the phosphorus concentration in molten steel at the time of converter blowing in MURC operation. Another object is to provide a method for estimating phosphorus concentration in molten steel and a converter blowing control device.

In order to solve the above-described problems, according to one aspect of the present invention, the dephosphorization process, the intermediate desulfurization process for removing slag generated by the dephosphorization process, and the decarburization process are performed in the same manner. A method for estimating a phosphorus concentration in molten steel used for primary refining performed using a furnace, the hot metal data acquiring step for acquiring hot metal data relating to the hot metal before the dephosphorization process, and a slag level at the time of the dephosphorization process Slag level data acquisition step, exhaust gas data acquisition step for acquiring the exhaust gas component and exhaust gas flow rate during the decarburization process, and molten steel data acquisition for acquiring the molten steel temperature and carbon concentration in the molten steel by sublance measurement during the decarburization process Data relating to the step, the slag level, the exhaust gas component, the exhaust gas flow rate, the molten steel temperature and the carbon concentration, and the dephosphorization treatment The dephosphorization rate constant is calculated using the operating conditions related to the intermediate waste treatment and the decarburization treatment, and the calculated dephosphorization rate constant and the molten iron phosphorus concentration at the start of the dephosphorization treatment are used. And a phosphorus concentration estimation step for estimating a phosphorus concentration in the molten steel at the time of the decarburization treatment after the sublance measurement.

In the calculation of the dephosphorization rate constant, a categorical variable that identifies a cluster obtained by time-series clustering performed on a plurality of time-series data of the slag level acquired in the past operation may be used.

In the calculation of the dephosphorization rate constant, an average value of the time series data of the slag level obtained during the dephosphorization process may be used.

Moreover, in order to solve the said subject, according to another viewpoint of this invention, the dephosphorization process, the intermediate | middle waste process which exhausts the slag produced | generated by the said dephosphorization process, and the decarburization process, A converter blowing control apparatus used for primary refining performed using the same converter, a hot metal data acquisition unit for acquiring hot metal data related to hot metal before the dephosphorization process, and a slag level during the dephosphorization process The slag level data acquisition unit for acquiring the exhaust gas component, the exhaust gas component acquisition unit for acquiring the exhaust gas flow rate during the decarburization treatment, and the sublance measurement during the decarburization treatment to obtain the molten steel temperature and the carbon concentration in the molten steel A molten steel data acquisition unit, data on the slag level, the exhaust gas component, the exhaust gas flow rate, the molten steel temperature and the carbon concentration, the dephosphorization process, the intermediate waste treatment process, and The dephosphorization rate constant is calculated using the operating conditions related to the decarburization treatment, and the calculated dephosphorization rate constant and the molten iron phosphorus concentration at the start of the dephosphorization treatment are used to calculate the dephosphorization rate constant after the sublance measurement. There is provided a converter blowing control device, comprising a phosphorus concentration estimation unit that estimates a phosphorus concentration in the molten steel at the time of decarburization treatment.

The phosphorus concentration estimator is a categorical variable that identifies clusters obtained by time-series clustering performed on a plurality of time-series data of the slag levels acquired in the past operation in the calculation of the dephosphorization rate constant. May be used.

The phosphorus concentration estimation unit may use an average value of the time series data of the slag level obtained during the dephosphorization process in the calculation of the dephosphorization rate constant.

In the above method for estimating phosphorus concentration in molten steel and the above-mentioned converter blowing control device, the dephosphorization rate constant is calculated using various data including slag level and operating conditions, and the calculated dephosphorization rate constant is used in the molten steel. The phosphorus concentration is estimated. As a result, the operating factors related to the slag removal generated in the converter during the primary refining, where the dephosphorization treatment, intermediate waste treatment and decarburization treatment are performed consistently in the same converter, are used to estimate the phosphorus concentration in the molten steel. It can be reflected. Therefore, the phosphorus concentration in molten steel can be estimated more accurately.

As described above, according to the present invention, it is possible to accurately estimate the phosphorus concentration in molten steel at the time of converter blowing by MURC operation.

It is a graph which shows the time series data of the slag level at the time of a dephosphorization process. It is a figure which shows the result of the time series clustering performed with respect to the time series data of a slag level. It is a figure which shows the result of the time series clustering performed with respect to the time series data of a slag level. It is a figure which shows the result of the time series clustering performed with respect to the time series data of a slag level. It is a figure which shows the result of the time series clustering performed with respect to the time series data of a slag level. It is a figure which shows the result of the time series clustering performed with respect to the time series data of a slag level. It is a figure which shows the result of the time series clustering performed with respect to the time series data of a slag level. It is a figure which shows the structural example of the converter blowing system which concerns on one Embodiment of this invention. It is a figure which shows an example of the flowchart of the phosphorus concentration concentration estimation method in molten steel by the converter blowing system which concerns on the same embodiment. It is a figure which shows the estimation error with respect to the track record value of the dephosphorization rate constant k at the time of a sublance measurement. It is a figure which shows the estimation error with respect to the track record value of the dephosphorization rate constant k at the time of a sublance measurement. It is a figure which shows the estimation error with respect to the track record value of the dephosphorization rate constant k at the time of a sublance measurement. It is a figure which shows the estimation error with respect to the track record value of the dephosphorization rate constant k at the time of a sublance measurement. It is a figure which shows the estimation error with respect to the actual value of phosphorus concentration in molten steel at the time of a sublance measurement. It is a figure which shows the estimation error with respect to the actual value of phosphorus concentration in molten steel at the time of a sublance measurement. It is a figure which shows the estimation error with respect to the actual value of phosphorus concentration in molten steel at the time of a sublance measurement. It is a figure which shows the estimation error with respect to the actual value of phosphorus concentration in molten steel at the time of a sublance measurement. It is a figure which shows the estimation error with respect to the actual value of the dephosphorization rate constant k at the time of an end point. It is a figure which shows the estimation error with respect to the actual value of the dephosphorization rate constant k at the time of an end point. It is a figure which shows the estimation error with respect to the actual value of the dephosphorization rate constant k at the time of an end point. It is a figure which shows the estimation error with respect to the actual value of the dephosphorization rate constant k at the time of an end point. It is a figure which shows the estimation error with respect to the actual value of the phosphorus concentration in molten steel at the time of an end point. It is a figure which shows the estimation error with respect to the actual value of the phosphorus concentration in molten steel at the time of an end point. It is a figure which shows the estimation error with respect to the actual value of the phosphorus concentration in molten steel at the time of an end point. It is a figure which shows the estimation error with respect to the actual value of the phosphorus concentration in molten steel at the time of an end point.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

Note that pig iron or steel may be present in the converter at the time of decarburization depending on the carbon concentration. However, in the following explanation, in order to avoid complicated explanation, Or “molten steel” will be referred to as “molten steel” for convenience. For the dephosphorization process, the word “hot metal” is used.

<< 1. Method for Estimating Phosphorus Concentration in Molten Steel According to this Embodiment >>
Before describing the configuration and function of the converter blowing system 1 according to the present embodiment, a method for estimating the phosphorus concentration in molten steel according to the present embodiment will be described. In the following description, unless otherwise specified, the concentration unit (mass%) of each component is described as (%).

(Method of estimating phosphorus concentration in molten steel using operating conditions and operating factors)
Assuming that the temporal change in phosphorus concentration [P] (%) in molten steel during blowing is expressed by the primary reaction equation, the primary reaction equation is expressed as the following equation (1).

Here, in the above formula (1), [P] _ini is the initial phosphorus concentration (molten phosphorus concentration) (%), and k is the dephosphorization rate constant (sec ⁻¹ ). Note that the “initial value of phosphorus concentration” here means the phosphorus concentration at the start of the dephosphorization process.

If an accurate dephosphorization rate constant k is obtained, the phosphorus concentration in molten steel can be estimated with high accuracy. However, in general, the dephosphorization rate constant k in actual blowing is not constant and is considered to vary under the influence of various operating conditions. Therefore, for example, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2013-23696), not only static information such as hot metal components and hot metal temperature, but also data relating to exhaust gas components that are measured sequentially. Further, the dephosphorization rate constant k is estimated by utilizing dynamic information during blowing such as exhaust gas data such as data relating to the exhaust gas flow rate. Hereinafter, a method for estimating the dephosphorization rate constant k will be described.

From the above formula (1), the phosphorus concentration in the molten steel after t seconds from the start of blowing (dephosphorization treatment start) is expressed by the following formula (2).

If it does so, the dephosphorization rate constant k for every charge can be calculated | required using the past operation performance data. For example, the dephosphorization rate constant k _i for the charge i is calculated using the following equation (3).

Here, in the above formula (3), [P] _{end, i} is the phosphorus concentration (%) in the molten steel at the time of blowing, and t _{end, i} is from the start of dephosphorization treatment (at the start of blowing). This is the elapsed time (seconds) up to the point of time of blowing.

Then, a model formula having the dephosphorization rate constant k obtained by the formula (3) as an objective variable is created in advance. This model formula can be appropriately constructed by various statistical methods. In the present embodiment, as the model formula, a regression formula obtained by a well-known multiple regression analysis method using various operation factors X as explanatory variables is used. The regression equation is constructed as the following equation (4). In actual blowing, the dephosphorization rate constant k is estimated by substituting the operation factor X at the time of the blowing into the following equation (4), and the dephosphorization rate constant k is applied to the above equation (2). Thus, the phosphorus concentration in the molten steel can be estimated.

Here, in the above formula (4), α _j is a regression coefficient corresponding to the j-th operation factor X _j , and α ₀ is a constant. Further, specific examples of the operation factor X include the operation factors shown in Table 1 below. However, the operation factor shown in the following Table 1 is merely an example, and any operation factor X may be considered in the estimation of the dephosphorization rate constant k. In addition, all or part of the operating factors included in Table 1 below may be used for estimating the dephosphorization rate constant k.

Further, according to the above-mentioned Patent Document 1, the in-furnace oxygen storage basic unit obtained by calculating the oxygen balance from the exhaust gas flow rate, exhaust gas component, top bottom blown gas flow rate, auxiliary raw material input amount and hot metal component during blowing. It was shown that the effect on the dephosphorization rate constant is large. Therefore, in the above-mentioned patent document 1, dynamic operation during blowing such as the unit oxygen amount accumulated in the furnace obtained by utilizing the exhaust gas data and the like, and the top blowing lance height, the oxygen gas flow rate, the bottom blowing gas flow rate, and the like. It is shown that the dephosphorization rate constant can be estimated with higher accuracy by further adopting the factors as explanatory variables of the regression equation shown in the above equation (4) in addition to the explanatory variables shown in Table 1. ing.

(Utilization of data related to slag level)
By the way, in the converter blowing method like MURC mentioned above, the dephosphorization process, the intermediate waste treatment, and the decarburization process are continuously performed by the same converter. Therefore, not only the operation conditions related to the dephosphorization process and the decarburization process as disclosed in the above-mentioned Patent Document 1, but also the operation conditions related to the intermediate waste treatment are used to estimate the dephosphorization rate constant according to the present embodiment. Can be used. Examples of the operation conditions related to the intermediate waste treatment include an intermediate waste time and an amount of intermediate slag.

Among these, the amount of slag discharged in the middle is considered to greatly affect the phosphorus concentration in molten steel during the decarburization process. The present inventors have found that the amount of the slag discharged in the middle is deeply related to the slag level (slag height) during the dephosphorization process. For example, in the intermediate evacuation process, when the slag level is high, slag is likely to be evacuated, and when the slag level is low, slag is difficult to be evacuated. That is, the amount of slag that is eliminated in the middle can vary according to the slag level. Therefore, the present inventors adopted the slag level of slag that can be generated in the converter during blowing during dephosphorization treatment as an operating factor related to the estimation of the phosphorus concentration in molten steel, thereby estimating the estimation accuracy of the phosphorus concentration in molten steel. I thought that I could improve more. Hereinafter, data relating to the slag level and examples of its use will be described.

FIG. 1 is a graph showing slag level time-series data during dephosphorization processing. The data shown by the graph is data obtained by subjecting the actually obtained slag level data to standardization processing so that the average = 0 and the standard deviation = 1. The time series data is time series data acquired from the start of blowing in the dephosphorization process to the time of blowing stop.

Referring to FIG. 1, it can be seen that the slag level is increased at the end of the dephosphorization process. That is, the generation of slag (slag forming) proceeds at the end of the dephosphorization process. Therefore, in this embodiment, the data relating to the slag level at the end of the blowing process during the dephosphorization process can be used as one of the operation factors X _j that is the explanatory variable of the equation (4). Note that “the end of dephosphorization treatment (also referred to as“ the end of blowing during dephosphorization ”)” is 1/3 to 1 / of the total elapsed time from the start of blowing in the dephosphorization to the point of blowing stop. It means the period from the time of blowing stop to the time of going back by the time corresponding to about 4. For example, if the total elapsed time from the start of blowing to the point of blow stop is 180 seconds, the end of the dephosphorization process starts from the point when 120 to 135 seconds have passed since the start of blowing. Corresponds to the period up to the time.

In the present embodiment, for example, the operation factor X _j, which is an explanatory variable of the equation (4) in which the average value of the time series data of the slag level at the end of the dephosphorization process is a regression equation for estimating the dephosphorization rate constant k. May be used as Thereby, the amount of slag generated by the dephosphorization process can be reflected in the estimation of the dephosphorization rate constant k.

In the present embodiment, for example, a categorical variable that identifies a cluster obtained by performing time-series clustering on slag level time-series data may be used as an explanatory variable. Time series clustering is a technique for obtaining a distance between time series data and performing clustering based on the distance. By treating the transition of the slag level as time series data, complex behavior of the slag level that cannot be expressed by a simple average value (in other words, the slag level time that is averaged in the process of calculating the average value) It is possible to reflect such a complicated behavior of the slag level more accurately.

Hereinafter, the case where a categorical variable for identifying a cluster obtained by performing time series clustering on slag level time series data is used as an explanatory variable will be described in detail.

In this embodiment, first, time-series clustering is performed in advance on the time-series data at the slag level at the end of blowing, which is acquired from past operation data. In the present embodiment, the nearest neighbor method of hierarchical clustering is used as a time series clustering method. The time series clustering method is not limited to this method, and for example, a non-hierarchical clustering k-means method may be used. In this embodiment, time-series clustering is performed so that these time-series data are classified into six clusters, but the number of clusters is not particularly limited. About the number of clusters, it sets suitably according to the result of clustering.

2A to 2F are diagrams showing the results of time series clustering performed on time series data at the slag level. 2A to 2F are diagrams respectively showing the results of time-series clustering for clusters corresponding to each categorical variable (No. 1 to 6). The data relating to the slag level shown in each figure was obtained by subjecting the actually obtained slag level data to standardization processing so that the average = 0 and the standard deviation = 1. It is data. Moreover, the time series data of the slag level used for the time series clustering according to the present embodiment is data obtained from the slag level up to the point 50 seconds after the blowing stop in the dephosphorization process (FIG. In FIG. 2A to FIG. 2F, the time point of blowing time = 50 seconds corresponds to the time of blowing blowing in the dephosphorization process, and the time point of blowing time = 0 seconds is a time point that goes back 50 seconds from the time of blowing. Yes.) The time range for selecting the slag level time-series data used for this time-series clustering is not particularly limited. For example, the target range is the trend of the slag level time-series data actually obtained by the level meter, or the transition. It can be set as appropriate based on the operating state of the furnace blowing facility.

In FIGS. 2A to 2F, each broken line in each figure shows a change with time in the slag level in one dephosphorization process. As shown in FIGS. 2A to 2F, data having high similarity between slag level time-series data are classified into the same cluster. For example, the cluster No. 2 categorizes time-series data having a high slag level increase rate and a high slag level at the time of intermediate waste (that is, a slag level at the time of blowing blowing in the dephosphorization process). On the other hand, the cluster No. 5 classifies time-series data with small changes in the slag level transition.

In this way, each cluster classified by the clustering executed in advance is compared with the time series data of the slag level obtained at the time of blowing in the dephosphorization process, and the cluster having the highest similarity is selected and the cluster is selected. Can be adopted as the operation factor X _j which is an explanatory variable of the equation (4). Thereby, not only the amount of slag generated in the dephosphorization process, but also the tendency of slag forming at the end of blowing during the dephosphorization process can be reflected in the estimation of the phosphorus concentration in the molten steel. The difference in slag forming tendency is considered to be based on slag properties such as slag components. Therefore, since the influence of the slag properties in the dephosphorization reaction is further taken into consideration for the estimation of the phosphorus concentration in the molten steel, it is possible to further improve the estimation accuracy of the phosphorus concentration in the molten steel.

Here, a method of using the clustering result of the slag level data for estimating the dephosphorization rate constant k in actual operation will be described. First, time-series clustering is performed in advance on time-series data at the slag level at the end of blowing, which is acquired from past operation data, and the time-series data is classified into a plurality of clusters. Then, a regression equation (the above equation (4)) in which the categorical variable for each cluster is one of explanatory variables is constructed in advance for each cluster.

Next, an average value β _{ave, j} at a measurement point j (j = 1 to n) of a plurality of time-series data of slag levels classified into each cluster is calculated for each measurement point. The measurement point means the measurement time point of the slag level in the target range of the time series data. For example, in each cluster shown in FIGS. 2A to 2F, each time series data from the time point of blowing stop to the time point that goes back 50 seconds is classified. When the slag level is measured every second, the number of measurement points is 50 points.

Next, time series data (S _j ) of the slag level at the time of actual dephosphorization processing, which is a target for estimating the dephosphorization rate constant k, is acquired, and the similarity between the acquired time series data of the slag level and each cluster For example, the difference between the time series data S _j and the average value β _{ave, j} is obtained for each cluster. The cluster having the smallest difference is determined as the cluster to which the time series data (S _j ) belongs, and the categorical variable corresponding to this cluster is used as the explanatory variable related to the operation factor. Any known difference can be used as the difference, but the difference may be, for example, a sum of squared difference (SSD) expressed by the following equation (5). The difference is appropriately determined by a known statistical method.

As described above, the case where the categorical variable for identifying the cluster obtained by performing the time series clustering on the slag level time series data is used as the explanatory variable has been described in detail.

Note that the explanatory variable based on the slag level time-series data is not limited to the example described above. For example, the slag level at the time of blowing stop in the dephosphorization process, the intermediate value of the time series data of the slag level at the end of blowing, the rate of change of the time series data, or the like may be used as the explanatory variable.

In the above, the estimation method of the phosphorus concentration in the molten steel which concerns on this embodiment was demonstrated.

<< 2. Converter Blowing System According to this Embodiment >>
<2.1. Configuration of converter blowing system>
Then, an example of the system for implement | achieving the estimation method of the phosphorus concentration in molten steel which concerns on this embodiment shown above is demonstrated. FIG. 3 is a diagram illustrating a configuration example of the converter blowing system 1 according to an embodiment of the present invention. Referring to FIG. 3, the converter blowing system 1 according to this embodiment includes a converter blowing facility 10, a converter blowing control device 20, a measurement control device 30, and an operation database 40.

(Converter blowing equipment)
The converter blowing facility 10 includes a converter 11, a flue 12, an upper blowing lance 13, a sub lance 14, an exhaust gas component analyzer 101, an exhaust gas flow meter 102, and a level meter 103. For example, the converter blowing facility 10 starts and stops the supply of oxygen to the hot metal by the top blowing lance 13 based on the control signal output from the measurement control device 30, the component concentration in the molten steel and the molten steel by the sublance 14. Processing relating to temperature measurement, introduction of cold material, and hot metal and slag removal by the converter 11 is performed. The converter blowing equipment 10 includes an acid feeding device for supplying oxygen to the top blowing lance 13, a coolant supply device having a drive system for supplying coolant to the converter 11, and a converter. Various apparatuses generally used for blowing by a converter such as an auxiliary raw material charging apparatus having a drive system for charging auxiliary raw materials to the furnace 11 may be provided.

An upper blowing lance 13 used for blowing is inserted from the furnace port of the converter 11, and oxygen 15 sent from the acid feeding device is supplied to the molten iron in the furnace through the upper blowing lance 13. In addition, an inert gas such as nitrogen gas or argon gas can be introduced from the bottom of the converter 11 as the bottom blowing gas 16 for stirring the hot metal. In the converter 11, hot metal discharged from the blast furnace, a small amount of iron scrap, cold material for adjusting the hot metal (molten steel) temperature, and auxiliary materials for slag formation such as quick lime are charged / injected. The When the auxiliary material is powder, the powdered auxiliary material may be supplied into the converter 11 together with the oxygen 15 through the top blowing lance 13.

In the primary refining, as shown in the above chemical formula (101), phosphorus contained in the hot metal chemically reacts with iron oxide contained in the slag in the converter and the auxiliary raw material containing the calcium oxide-containing material (desorption). Phosphorus reaction), taken into slag. That is, the dephosphorization reaction is promoted by increasing the iron oxide concentration in the slag by blowing.

In the primary refining, the carbon in the hot metal undergoes an oxidation reaction with oxygen supplied from the top blowing lance 13 (decarburization reaction). Thereby, CO or CO ₂ exhaust gas is generated. These exhaust gases are discharged from the converter 11 to the flue 12.

In this way, in the converter blowing, the blown oxygen reacts with carbon, phosphorus, silicon, or the like in the hot metal to produce an oxide. The oxide produced by blowing is discharged as exhaust gas or stabilized as slag. Carbon is removed by an oxidation reaction in blowing, and phosphorus and the like are taken into and removed from the slag, thereby producing a steel with low carbon and less impurities.

Moreover, the sublance 14 inserted from the furnace port of the converter 11 is immersed in the molten steel at a predetermined timing during the decarburization process, and measures the component concentration in the molten steel including the carbon concentration, the molten steel temperature, and the like. Used for. The measurement of molten steel data such as the component concentration and / or molten steel temperature by the sublance 14 is hereinafter referred to as “sublance measurement”. Molten steel data obtained by the sublance measurement is transmitted to the converter blowing control device 20 via the measurement control device 30.

The exhaust gas generated by blowing flows into a flue 12 provided outside the converter 11. The flue 12 is provided with an exhaust gas component analyzer 101 and an exhaust gas flow meter 102. The exhaust gas component analyzer 101 analyzes components contained in the exhaust gas. The exhaust gas component analyzer 101 analyzes, for example, the concentrations of CO and CO ₂ contained in the exhaust gas. The exhaust gas flow meter 102 measures the flow rate of the exhaust gas. The exhaust gas component analyzer 101 and the exhaust gas flow meter 102 sequentially perform exhaust gas component analysis and flow rate measurement at a predetermined sampling period (for example, a period of 5 to 10 seconds). The component analysis and flow rate measurement of the exhaust gas are performed at least during the decarburization process. In order to calculate the oxygen storage unit consumption in the furnace used as the explanatory variable of the regression equation shown in the above formula (4), It is preferably performed throughout the smelting. The data relating to the exhaust gas component analyzed by the exhaust gas component analyzer 101 and the data relating to the exhaust gas flow rate measured by the exhaust gas flow meter 102 (hereinafter, these data are referred to as “exhaust gas data”) are measured and controlled. The time series data is output to the converter blowing control device 20 via 30. In order for the converter blowing control device 20 to sequentially estimate the phosphorus concentration in the molten steel, it is preferable that this exhaust gas data is sequentially output to the converter blowing control device 20.

Moreover, the converter blowing facility 10 includes a level meter 103 in the vicinity of the opening of the converter 11. The level meter 103 is a device that measures the bath surface level of molten iron (molten steel), slag, etc. in the converter 11 during converter blowing. In the present specification, this bath surface level is referred to as a slag level.

The slag level obtained by the level meter 103 is information reflecting the slag hatching status, and is used directly or indirectly as an explanatory variable of the regression equation shown in the above equation (4). The level meter 103 sequentially measures the slag level at a predetermined sampling period (for example, 1 second period). Data relating to the slag level obtained by the level meter 103 is output as time series data to the converter blowing control device 20 via the measurement control device 30.

Note that the level meter 103 can be realized by, for example, a microwave emission device, an antenna, an arithmetic device, and the like as disclosed in JP-A-2015-110817. In the level meter disclosed in the above document, the microwave injection device emits the microwave into the converter, the antenna detects the reflected wave reflected by the bath surface, and the arithmetic unit detects the emitted microwave and Based on the detected reflected wave, the bath surface level is measured.

(Converter Blowing Control Device)
The converter blowing control device 20 includes a data acquisition unit 201, a cluster determination unit 202, a clustering execution unit 203, a phosphorus concentration estimation unit 204, a converter blowing database 21 and an input / output unit 22. The converter blowing control device 20 includes hardware configurations such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a storage, and a communication device. The functions of the acquisition unit 201, the cluster determination unit 202, the clustering execution unit 203, the phosphorus concentration estimation unit 204, and the converter blowing database 21 are realized. The input / output unit 22 is realized by an input device such as a keyboard, a mouse, or a touch panel, an output device such as a display or a printer, and a communication device.

The converter blowing control device 20 includes various data stored in the converter blowing database 21, exhaust gas data acquired from the exhaust gas component analyzer 101 and the exhaust gas flow meter 102, molten steel data acquired from the sublance 14, and Using the data relating to the slag level acquired from the level meter 103 (that is, time series data of the slag level) as an input value, the phosphorus concentration in the molten steel is estimated. The phosphorus concentration in the molten steel is estimated by the function of each functional unit of the converter blowing control device 20. Moreover, the converter blowing control apparatus 20 may use the estimated phosphorus concentration in molten steel for control of the operation in converter blowing. For example, when it is determined that the estimated phosphorus concentration in the molten steel exceeds the target phosphorus concentration in the molten steel stored as one of the target data 212, the converter blowing control device 20 determines the phosphorus concentration in the molten steel. However, the operating conditions of the converter blowing can be changed so that the phosphorus concentration is lower than the target phosphorus concentration in the molten steel. Thus, if the phosphorus concentration in molten steel can be estimated with high accuracy, the quality of the molten steel obtained by primary refining can be maintained high.

In addition, the specific function which each function part of the converter blowing control apparatus 20 which concerns on this embodiment has is mentioned later.

Also, the converter blowing control device 20 has a function of controlling the entire process related to hot metal pretreatment such as oxygen injection into the converter 11 and the introduction of cold materials and auxiliary materials. Further, for example, the converter blowing control device 20 is performed in general static control, and the amount of oxygen blown into the converter 11 and the amount of cold material before the start of blowing using a predetermined mathematical model or the like. It has a function of determining an input amount (hereinafter referred to as a cold material amount), an input amount of auxiliary materials, and the like. Further, for example, the converter blowing control device 20 has a function of controlling a measurement object, a measurement timing, and the like for sublance measurement performed in general dynamic control.

Specific processing in each function (not shown) (for example, the control method for charging the cold material and the auxiliary material described above, the amount of injected oxygen, the input amount of various cold materials and the auxiliary material, etc. before the start of blowing in the static control) Since various known methods can be applied as the method for controlling the sublance measurement and the control method for the lance measurement, detailed description thereof is omitted here.

The converter blowing database 21 is a database that stores various data used in the converter blowing control device 20, and is realized by a storage device such as a storage. The converter blowing database 21 stores, for example, hot metal data 211, target data 212, parameters 213, and the like, as shown in FIG. These data may be added, updated, changed, or deleted via an input device or a communication device (not shown). For example, data used for converter blowing may be added to the converter blowing database 21 among various data stored in an operation database 40 described later. Various data stored in the converter blowing database 21 is called by the data acquisition unit 201. In addition, although the memory | storage device which has the converter blowing database 21 which concerns on this embodiment is comprised integrally with the converter blowing control apparatus 20 as shown in FIG. 3, in other embodiment, The storage device having the converter blowing database 21 may be separated from the converter blowing control device 20.

The hot metal data 211 is various data relating to the hot metal in the converter 11. For example, the hot metal data 211 includes information about the hot metal (initial hot metal weight for each charge, concentration of hot metal components (carbon, phosphorus, silicon, iron, manganese, etc.), hot metal temperature, hot metal ratio, etc.). In addition to the hot metal data 211, various other information generally used in hot metal preliminary treatment and decarburization processing (for example, information on the addition of auxiliary materials and cold materials (information on the amounts of auxiliary materials and cold materials)) , Information about the sublance measurement (information about the measurement target, measurement timing, etc.), information about the amount of oxygen blown in, etc. can be included. The target data 212 includes data such as target component concentration and target temperature in hot metal (in molten steel) after dephosphorization, after decarburization, and during sublance measurement. The parameter 213 is various parameters used in the cluster determination unit 202 and the phosphorus concentration estimation unit 204. For example, the parameter 213 includes a parameter in a regression equation having an operation factor as an explanatory variable, and a parameter (such as a dephosphorization rate constant) for estimating a phosphorus concentration.

The input / output unit 22 has a function of acquiring, for example, an estimation result of the phosphorus concentration in molten steel by the phosphorus concentration estimating unit 204 and outputting the result to various output devices. For example, the input / output unit 22 may display the estimated phosphorus concentration in the molten steel to the operator. In addition, when the converter blowing control device 20 performs converter blowing control based on the estimated phosphorus concentration in molten steel, the input / output unit 22 relates to converter blowing based on the estimated phosphorus concentration in molten steel. The instruction may be output to the measurement control device 30. In this case, the instruction may be an instruction that is automatically generated by a function related to the converter blowing control of the converter blowing control device 20, or the displayed phosphorus concentration in the molten steel (estimated value). The instruction may be input by an operation of an operator who has browsed the information. The input / output unit 22 may have an input interface function for adding, updating, changing, or deleting various data stored in the converter blowing database 21. Further, the input / output unit 22 may output the various data acquired by the data acquisition unit 201, the determination result by the cluster determination unit 202, and the estimation result by the phosphorus concentration estimation unit 204 to the operation database 40.

(Measurement control device)
The measurement control device 30 includes a hardware configuration such as a CPU, ROM, RAM, storage, and communication device. The measurement control device 30 communicates with each device provided in the converter blowing facility 10 and has a function of controlling the entire operation of the converter blowing facility 10. For example, the measurement control device 30 tilts the converter 11 for intermediate waste treatment, inputs the cooling material and auxiliary materials to the converter 11, and blows up the top in response to an instruction from the converter blowing control device 20. The operation related to the injection of oxygen 15 into the lance 13 and the immersion of the sublance 14 into the molten steel and the measurement of the sublance are controlled. In addition, the measurement control device 30 acquires data obtained from each device of the converter blowing facility 10 such as the exhaust gas component analyzer 101, the exhaust gas flow meter 102, the level meter 103, the sublance 14, and the like, It transmits to the control apparatus 20.

(Operation database)
The operation database 40 is a database realized by a storage device such as a storage, and is a database that stores various data related to the operation of the converter blowing. The various data includes data obtained from each device of the converter blowing facility 10 acquired by the data acquisition unit 201, a determination result by the cluster determination unit 202, and an estimation result by the phosphorus concentration estimation unit 204. The operation database 40 according to the present embodiment accumulates data relating to the slag level measured by the level meter 103 (that is, time series data of the slag level) for each operation. Further, the operation database 40 according to the present embodiment outputs slag level time-series data for each operation to the clustering execution unit 203. In addition, although the memory | storage device which has the operation database 40 which concerns on this embodiment is comprised separately from the converter blowing control apparatus 20, as shown in FIG. 3, in other embodiment, the operation database 40 is comprised. The storage device having the structure may be integrated with the converter blowing control device 20.

<2.2. Configuration and function of each functional unit>
Next, the configuration and function of each functional unit of the converter blowing control device 20 according to the present embodiment will be described.

Referring again to FIG. 3, the converter blowing control apparatus 20 according to the present embodiment includes the functional units of a data acquisition unit 201, a cluster determination unit 202, a clustering execution unit 203, and a phosphorus concentration estimation unit 204.

(Data acquisition unit)
The data acquisition unit 201 acquires various data for estimating the phosphorus concentration in molten steel. For example, the data acquisition unit 201 acquires hot metal data 211, target data 212, and parameters 213 stored in the converter blowing database 21. That is, the data acquisition unit 201 has a function as a hot metal data acquisition unit. These data are acquired at the latest before the estimation process of the phosphorus concentration in molten steel by the phosphorus concentration estimating unit 204 is started. The data acquisition unit 201 according to the present embodiment acquires various data stored in the converter blowing database 21 before the start of converter blowing.

Further, the data acquisition unit 201 acquires exhaust gas data output from the exhaust gas component analyzer 101 and the exhaust gas flow meter 102. That is, the data acquisition unit 201 has a function as an exhaust gas data acquisition unit. The acquired exhaust gas data is time series data. The data acquisition unit 201 according to the present embodiment sequentially acquires exhaust gas data that the exhaust gas component analyzer 101 and the exhaust gas flow meter 102 sequentially measure. In other embodiments, the data acquisition unit 201 may acquire the exhaust gas data collectively after the dephosphorization process.

In addition, the data acquisition unit 201 acquires data relating to the slag level output from the level meter 103. That is, the data acquisition unit 201 has a function as a slag level data acquisition unit. The data related to the acquired slag level is time series data. The slag level is acquired during the dephosphorization process. The data acquisition unit 201 according to the present embodiment sequentially acquires data related to the slag level that the level meter 103 sequentially measures during the dephosphorization process. In other embodiments, the data acquisition unit 201 may acquire data related to the slag level in a lump after dephosphorization processing.

Further, the data acquisition unit 201 acquires molten steel data obtained by sublance measurement by the sublance 14 during the decarburization process. That is, the data acquisition unit 201 has a function as a molten steel data acquisition unit.

In addition, the data acquisition part 201 acquires the data which concern on a dephosphorization process, an intermediate | middle waste disposal process, and a decarburization process besides the various data mentioned above. The data acquisition unit 201 acquires data output from various devices provided in the converter blowing facility 10 via the measurement control device 30.

The data acquisition unit 201 outputs the acquired data to the cluster determination unit 202 and the phosphorus concentration estimation unit 204. The data acquired by the data acquisition unit 201 is stored in the operation database 40.

(Cluster determination unit, clustering execution unit)
The cluster determination unit 202 determines the cluster having the highest similarity among the slag level time-series data acquired from the data acquisition unit 201 among the plurality of clusters extracted by the clustering execution unit 203. Here, the method of calculating the similarity is not particularly limited, and various known methods can be used as appropriate. As such similarity, for example, as described above, the time-series data of the slag level of interest and the sum of squared differences between each cluster can be used. The categorical variable corresponding to the cluster determined by the cluster determination unit 202 is output to the phosphorus concentration estimation unit 204. The categorical variable is used as an operation factor X _j that is an explanatory variable of the regression equation shown in Expression (4) used for estimation by the phosphorus concentration estimation unit 204.

Further, the clustering execution unit 203 performs clustering on the slag level time-series data in the past operation acquired from the operation database 40, and extracts a plurality of clusters. Information relating to the cluster extracted by the clustering execution unit 203 is output to the cluster determination unit 202. In addition, information regarding the cluster may be output to the operation database 40. Further, the clustering execution unit 203 may appropriately perform clustering when the time series data of the slag level in the past operation stored in the operation database 40 is updated.

In addition, when not using the said categorical variable as an explanatory variable in other embodiment, the cluster determination part 202 and the clustering execution part 203 may not be included in the converter blowing control apparatus 20. FIG.

(Phosphorus concentration estimation part)
The phosphorus concentration estimation unit 204 uses the various data output from the data acquisition unit 201 and the categorical variable that is a variable for identifying the cluster output from the cluster determination unit 202, and uses the dephosphorization rate constant k and the phosphorus concentration in molten steel. Is estimated. Specifically, the phosphorus concentration estimation unit 204 first calculates the dephosphorization rate constant k by substituting the above various data and categorical variables as explanatory variables into the regression equation shown in the above equation (4). And the phosphorus concentration estimation part 204 estimates the phosphorus concentration in molten steel by substituting the dephosphorization rate constant k calculated to the said Formula (2). The phosphorus concentration estimation unit 204 sequentially estimates the dephosphorization rate constant k and the phosphorus concentration in the molten steel after the sublance measurement by the sublance 14 (that is, after the start of the acquisition of the molten steel data by the data acquisition unit 201). That is, the phosphorus concentration estimation unit 204 estimates the dephosphorization rate constant k and the phosphorus concentration in the molten steel in the range from the sublance measurement to the time when the decarburization treatment is stopped (at the end point).

The configuration and function of each functional unit of the converter blowing control device 20 according to the present embodiment has been described above with reference to FIG. Although not shown in FIG. 3, the converter blowing control device 20 may further include an operation amount calculation unit. Based on the phosphorus concentration in the molten steel estimated by the phosphorus concentration estimation unit 204, the operation amount calculation unit calculates an operation amount such as the amount of blown oxygen or cold material in the decarburization process, or the top blow lance height. Also good. The function of the operation amount calculation unit may be the same as the function disclosed in Patent Document 1, for example. The phosphorus concentration in molten steel estimated by the phosphorus concentration estimating unit 204 according to the present embodiment is higher in accuracy than the phosphorus concentration in molten steel estimated by the technique disclosed in Patent Document 1. Therefore, since the reliability of the operation amount calculated by the operation amount calculation unit is high, the actual phosphorus concentration in molten steel can be made closer to the target phosphorus concentration in molten steel.

<< 3. Flow of estimation method for phosphorus concentration in molten steel >>
FIG. 4 is a diagram showing an example of a flowchart of a method for estimating phosphorus concentration in molten steel by the converter blowing system 1 according to the present embodiment. The flow of the method for estimating the phosphorus concentration in molten steel by the converter blowing system 1 according to this embodiment will be described with reference to FIG. In addition, each process shown in FIG. 4 respond | corresponds to each process performed by the converter blowing control apparatus 20 shown in FIG. Therefore, details of each process shown in FIG. 4 are omitted, and only an outline of each process is described.

In the molten steel phosphorus concentration estimation method according to the present embodiment, first, various data such as data stored in the converter blowing database 21 are acquired before the start of converter blowing (step S101). Specifically, in step S101, the data acquisition unit 201 acquires hot metal data 211, target data 212, and parameters 213.

Next, data related to the dephosphorization process and the intermediate evacuation process is acquired during the dephosphorization process and the intermediate evacuation process (step S103). Specifically, in step S <b> 103, the data acquisition unit 201 sequentially acquires data related to the slag level measured by the level meter 103 from the level meter 103.

Next, a cluster to be used as an operation factor is determined based on the slag level time-series data at the time of dephosphorization acquired in step S103 (step S105). Specifically, in step S105, the cluster determination unit 202 selects the cluster having the highest similarity among the clusters extracted by the clustering execution unit 203 for the slag level time-series data during the dephosphorization process of the main charge. decide. The categorical variable corresponding to the cluster determined here is output to the phosphorus concentration estimation unit 204.

Next, data related to the decarburization process is acquired (step S107). Specifically, in step S107, the data acquisition unit 201 sequentially acquires exhaust gas data measured by the exhaust gas component analyzer 101 and the exhaust gas flow meter 102 from the exhaust gas component analyzer 101 and the exhaust gas flow meter 102. The acquisition of the exhaust gas data is continuously performed from the start of the decarburization process to the end point. In addition, at the timing when the lance measurement is performed, the data acquisition unit 201 acquires molten steel data.

In the method for estimating the phosphorus concentration in molten steel according to the present embodiment, the subsequent processing changes depending on whether or not the sublance measurement has already been performed (step S109). When the sublance measurement has not been performed yet (S109 / NO), the phosphorus concentration in the molten steel is not estimated, and data relating to decarburization processing such as repeated exhaust gas data is acquired (step S107). On the other hand, when the sublance measurement has already been performed (S109 / YES), the phosphorus concentration in the molten steel is estimated (step S111). Specifically, the phosphorus concentration estimation unit 204 first estimates the dephosphorization rate constant k and the phosphorus concentration in the molten steel at the time of sublance measurement using various data acquired by the data acquisition unit 201. This is because the molten steel temperature actual value and the molten steel carbon concentration actual value obtained by the sublance measurement are effective by increasing the accuracy of the estimation of the dephosphorization rate constant k. More specifically, first, by substituting explanatory variables based on various data including actual molten steel temperature values and actual carbon concentration actual values obtained by sublance measurement into the regression equation of the above equation (4), a dephosphorization rate constant. k. Next, assuming that the obtained dephosphorization rate constant k is the same value from the start of the dephosphorization process to the time of the sublance measurement, the molten iron phosphorus concentration is set to the phosphorus concentration initial value [P] _ini , and the dephosphorization process is performed. By substituting the elapsed time from the start to the sublance measurement time to t in the above equation (2), the phosphorus concentration [P] at the sublance measurement time is obtained. Thus, even if the phosphorus concentration at the time of the sublance measurement is estimated from the start of the dephosphorization process using the dephosphorization rate constant k estimated at the time of the sublance measurement, the phosphorus concentration can be obtained with sufficient accuracy as shown in the following examples. Since it can be estimated, there is no practical problem.

From the measurement of the sublance until the end of the decarburization process, using the estimated phosphorus concentration in the molten steel at the time of the sublance measurement as an initial value, the estimation of the dephosphorization rate constant k by the above equation (4) and the estimated k are used. The estimation of the phosphorus concentration in the molten steel by the above equation (2) is repeatedly performed (step S113). Specifically, when the decarburization process is not completed (S113 / NO), the processes according to steps S107 to S111 are repeatedly performed. On the other hand, when the decarburization process is finished (S113 / YES), the estimation process of the phosphorus concentration in the molten steel according to the present embodiment is finished.

The flow of the method for estimating the phosphorus concentration in molten steel according to this embodiment has been described above with reference to FIG. In addition, the step shown in the flowchart which concerns on the estimation method of the phosphorus concentration in molten steel which concerns on this embodiment shown in FIG. 4 is only an example to the last.

For example, the timing at which the processes according to steps S101 to S105 are executed is not particularly limited as long as the process for estimating the phosphorus concentration in molten steel in step S111 is started. Specifically, in another embodiment, when the data acquisition unit 201 acquires exhaust gas data and slag level data collectively from various devices, the data acquisition processing in step S101 and step S103, and the cluster in S105 This determination process may be completed before the estimation process of the phosphorus concentration in molten steel in step S111 is started. This is because it is sufficient if the data used for estimating the phosphorus concentration in the molten steel is available at the start of the estimation process of the phosphorus concentration in the molten steel in step S111.

<< 4. Summary >>
The amount of slag discharged in the intermediate waste treatment affects the reaction direction and reaction rate of the dephosphorization reaction that affects the phosphorus concentration in the molten steel. Further, it is said that the slag level in the dephosphorization process is related to the amount of slag discharged in the intermediate waste process. According to the present embodiment, as one of the operating factors used for the explanatory variable for calculating the dephosphorization rate constant k, the time series data (and / or the slag level of the slag level at the time of blowing in the dephosphorization process). Average value of time series data) is used. That is, the amount of slag discharged during the intermediate waste treatment related to the dephosphorization reaction is applied to the estimation of the phosphorus concentration in the molten steel. Therefore, according to the present embodiment, it is possible to further increase the estimation accuracy of the phosphorus concentration in the molten steel in the converter blowing in which the intermediate waste treatment is performed.

Further, according to the present embodiment, a categorical variable that identifies a cluster obtained by time-series clustering performed on slag level time-series data at the time of past operation is used as an explanatory variable related to an operation factor. Then, a cluster similar to the tendency indicated by the time series data of the slag level obtained at the time of actual operation is determined, and the categorical variable corresponding to the determined cluster is represented as an explanatory variable related to the operation factor of the charge in the regression equation. Assigned. As a result, not only the amount of slag produced in the dephosphorization process but also the tendency of slag forming at the end of blowing during the dephosphorization process can be reflected in the estimation of the dephosphorization rate constant k. That is, it is possible to further increase the estimation accuracy of the phosphorus concentration in the molten steel in the converter blowing where the intermediate waste treatment is performed.

In addition, the structure shown in FIG. 3 is an example of the converter blowing system 1 which concerns on this embodiment to the last, and the specific structure of the converter blowing system 1 is not limited to this example. The converter blowing system 1 should just be comprised so that the function demonstrated above is realizable, and can take all the structures which can be generally assumed.

For example, all the functions provided in the converter blowing control device 20 may not be executed in one device, or may be executed by cooperation of a plurality of devices. For example, one device having only one or a plurality of functions of the data acquisition unit 201, the cluster determination unit 202, the clustering execution unit 203, and the phosphorus concentration estimation unit 204 is compared with other devices having other functions. By being connected so as to be communicable, a function equivalent to the converter blowing control device 20 shown in the figure may be realized.

Further, it is possible to create a computer program for realizing each function of the converter blowing control device 20 according to the present embodiment shown in FIG. 3 and mount it on a processing device such as a PC. In addition, a computer-readable recording medium storing such a computer program can be provided. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, or the like. Further, the above computer program may be distributed via a network, for example, without using a recording medium.

Next, examples of the present invention will be described. In order to confirm the effect of the present invention, in this example, the dephosphorization rate constant k obtained by the method for estimating phosphorus concentration in molten steel according to the present embodiment and the estimation accuracy of phosphorus concentration in molten steel were verified. In addition, the following Examples are only performed in order to verify the effect of this invention, and this invention is not limited to the following Examples.

As an explanatory variable used in the regression equation represented by the above equation (4), the operation factors shown in Table 1 were used in Comparative Example 1. On the other hand, in Example 1, in addition to the operation factors shown in Table 1 above, the average value of the time series data of the slag level at the end of the blowing process during the dephosphorization process was used as the explanatory variable. In Example 2, in addition to the operation factors shown in Table 1 above, categorical variables corresponding to the clusters determined by the cluster determination unit 202 for the slag level time-series data were used as explanatory variables. Further, in the third embodiment, as explanatory variables, in addition to the operation factors shown in Table 1 and the average value of the time series data of the slag level, the cluster determined by the cluster determination unit 202 for the time series data of the slag level is used. Corresponding categorical variables were used.

For each of the examples and comparative examples, the dephosphorization rate constant k and the phosphorus concentration in the molten steel at the time of sublance measurement and at the time of blowing in the decarburization treatment (at the end point) were calculated. The dephosphorization rate constant k was calculated using the above formula (4). The phosphorus concentration in the molten steel was calculated by substituting the dephosphorization rate constant k obtained by the above equation (4) into the above equation (2). The calculated dephosphorization rate constant k and the phosphorus concentration in the molten steel are hereinafter referred to as “estimated values”.

Incidentally, in order to verify the estimation accuracy of the dephosphorization rate constant k and the phosphorus concentration in the molten steel according to each example and comparative example, the actual values of the phosphorus concentration in the molten steel at the time of the sublance measurement and at the end point were measured. Moreover, the dephosphorization rate constant k based on the said performance value was computed by substituting the track record value of phosphorus concentration in molten steel to said Formula (2). An error (estimation error) between the estimated value and the actual value of the dephosphorization rate constant k and the phosphorus concentration in the molten steel according to each example and comparative example was calculated, and the standard deviation S.I. D. (%) Was calculated. Standard deviation D. It can be said that the smaller the is, the smaller the estimation error (that is, the higher the estimation accuracy).

First, the results relating to the estimation accuracy of the phosphorus removal rate constant k and the phosphorus concentration in the molten steel at the time of sublance measurement are shown in FIGS. 5A to 6D. 5A to 5D are diagrams showing an estimation error with respect to the actual value of the dephosphorization rate constant k at the time of measuring the sublance. FIG. 5A is a diagram illustrating an estimation error of a dephosphorization rate constant k at the time of sublance measurement in Example 1. FIG. 5B is a diagram showing an estimation error of the dephosphorization rate constant k at the time of sublance measurement in Example 2. FIG. 5C is a diagram showing an estimation error of the dephosphorization rate constant k at the time of sublance measurement in Example 3. FIG. 5D is a diagram showing an estimation error of a dephosphorization rate constant k at the time of sublance measurement in a comparative example.

6A to 6D are diagrams showing estimation errors with respect to the actual value of phosphorus concentration in molten steel at the time of sublance measurement. 6A is a diagram showing an estimation error with respect to the actual value of the phosphorus concentration in molten steel at the time of measuring the sublance in Example 1. FIG. 6B is a diagram showing an estimation error with respect to the actual value of phosphorus concentration in molten steel at the time of measuring the sublance in Example 2. FIG. FIG. 6C is a diagram showing an estimation error with respect to the actual value of phosphorus concentration in molten steel at the time of sublance measurement in Example 3. FIG. 6D is a diagram showing an estimation error with respect to the actual value of phosphorus concentration in molten steel at the time of measuring the sublance in the comparative example.

Referring to FIGS. 5A to 5D, it can be seen that in each example, the estimation accuracy of the dephosphorization rate constant k is improved as compared with the comparative example. Specifically, as shown in FIG. 5D, in the comparative example, the standard deviation S.I. D. Was 0.00395. On the other hand, as shown in FIG. 5A, FIG. 5B, and FIG. D. Is 0.00385, and in Example 2, the standard deviation S.E. D. Is 0.00368, and in the third embodiment, the standard deviation S.I. D. Was 0.00361.

Referring to FIGS. 6A to 6D, it can be seen that in each example, the estimation accuracy of the phosphorus concentration in molten steel is improved as compared with the comparative example. Specifically, as shown in FIG. 6D, in the comparative example, the standard deviation S.I. D. Was 0.00420. On the other hand, as shown in FIGS. 6A, 6B, and 6C, in the first embodiment, the standard deviation S.I. D. Is 0.00406, and in Example 2, the standard deviation S.E. D. Is 0.00385, and in Example 3, the standard deviation S.E. D. Was 0.00377.

From the above results, it was found that in each example, the dephosphorization rate constant k and the phosphorus concentration in molten steel at the time of sublance measurement can be estimated more accurately than in the comparative example. In particular, Example 2 and Example 3 in which variables corresponding to clusters obtained from time series data related to slag levels are used as explanatory variables indicate that the dephosphorization rate constant k and the phosphorus concentration in molten steel can be estimated more accurately. It was.

Next, the results relating to the dephosphorization rate constant k at the end point in the decarburization process and the estimation accuracy of the phosphorus concentration in the molten steel are shown in FIGS. 7A to 8D.
7A to 7D are diagrams showing an estimation error with respect to the actual value of the dephosphorization rate constant k at the end point. FIG. 7A is a diagram showing an estimation error of the dephosphorization rate constant k at the end point in the first embodiment. FIG. 7B is a diagram illustrating an estimation error of the dephosphorization rate constant k at the end point in the second embodiment. FIG. 7C is a diagram showing an estimation error of the dephosphorization rate constant k at the end point in Example 3. FIG. 7D is a diagram showing an estimation error of the dephosphorization rate constant k at the end point in the comparative example.

8A to 8D are diagrams showing an estimation error with respect to the actual value of the phosphorus concentration in the molten steel at the end point. FIG. 8A is a diagram showing an estimation error with respect to the actual value of phosphorus concentration in molten steel at the end point in Example 1. FIG. 8B is a diagram showing an estimation error with respect to the actual value of the phosphorus concentration in the molten steel at the end point in Example 2. FIG. 8C is a diagram showing an estimation error with respect to the actual value of phosphorus concentration in molten steel at the end point in Example 3. FIG. 8D is a diagram showing an estimation error with respect to the actual value of the phosphorus concentration in the molten steel at the end point in the comparative example.

7A to 7D, it can be seen that the estimation accuracy of the dephosphorization rate constant k is improved in each example as compared with the comparative example. Specifically, as shown in FIG. 7D, in the comparative example, the standard deviation S.I. D. Was 0.00664. On the other hand, as shown in FIGS. 7A, 7B, and 7C, in Example 1, the standard deviation S.E. D. Is 0.00656, and in Example 2, the standard deviation S.I. D. In Example 3, the standard deviation S.I of the estimation error is 0.00656. D. Was 0.00650.

Referring to FIGS. 8A to 8D, it can be seen that in each example, the estimation accuracy of the phosphorus concentration in the molten steel is improved as compared with the comparative example. Specifically, as shown in FIG. 8D, in the comparative example, the standard deviation S.I. D. Was 0.00102. On the other hand, as shown in FIGS. 8A, 8B, and 8C, in the first embodiment, the standard deviation S.I. D. Is 0.000101, and in Example 2, the standard deviation S.I of the estimation error is D. Is 0.000986, and in Example 3, the standard deviation S.E. D. Was 0.000982.

From the above results, it was found that in each example, the dephosphorization rate constant k at the end point and the phosphorus concentration in molten steel can be estimated with higher accuracy than in the comparative example. In particular, Example 2 and Example 3 in which variables corresponding to clusters obtained from time series data related to slag levels are used as explanatory variables indicate that the dephosphorization rate constant k and the phosphorus concentration in molten steel can be estimated more accurately. It was.

From the above, it was shown that in each example, the dephosphorization rate constant k and the phosphorus concentration in molten steel at the time of sublance measurement and at the end point can be estimated with higher accuracy than in the comparative example. In particular, as shown in Example 2 and Example 3, the accuracy is further improved by using a variable corresponding to the cluster obtained from the time series data relating to the slag level as an explanatory variable for calculating the dephosphorization rate constant k. Was shown to do.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Converter blowing system 10 Converter blowing equipment 11 Converter 12 Flue 13 Upper blow lance 14 Sublance 20 Converter blowing control apparatus 21 Converter blowing database 22 Input / output part 30 Measurement control apparatus 40 Operation database 101 Exhaust gas Component analyzer 102 Exhaust gas flow meter 103 Level meter 201 Data acquisition unit 202 Cluster determination unit 203 Clustering execution unit 204 Phosphorus concentration estimation unit

Claims

A method for estimating phosphorus concentration in molten steel used in primary refining, which uses a single converter for dephosphorization, intermediate waste treatment for removing slag produced by the dephosphorization treatment, and decarburization treatment. There,
A slag level data acquisition step for acquiring a slag level during the dephosphorization process;
An exhaust gas data acquisition step for acquiring exhaust gas components and exhaust gas flow rate during the decarburization treatment;
Molten steel data acquisition step of acquiring molten steel temperature and carbon concentration in molten steel by sublance measurement during the decarburization treatment,
Dephosphorization rate using the slag level, the exhaust gas component, the exhaust gas flow rate, the data relating to the molten steel temperature and the carbon concentration, and the operating conditions relating to the dephosphorization treatment, the intermediate waste treatment and the decarburization treatment A constant is calculated, and using the calculated dephosphorization rate constant and the molten iron phosphorus concentration at the start of the dephosphorization process, the phosphorus concentration in the molten steel at the time of the decarburization process after the sublance measurement is estimated. A phosphorus concentration estimation step;
A method for estimating phosphorus concentration in molten steel.
In the calculation of the dephosphorization rate constant, a categorical variable for identifying a cluster obtained by time series clustering performed on a plurality of time series data of the slag level obtained in a past operation is used. The method for estimating phosphorus concentration in molten steel as described.
The method for estimating phosphorus concentration in molten steel according to claim 1 or 2, wherein an average value of the time series data of the slag level obtained during the dephosphorization process is used in the calculation of the dephosphorization rate constant.
A converter blowing control apparatus used for primary refining that performs a dephosphorization process, an intermediate desulfurization process for discharging slag generated by the dephosphorization process, and a decarburization process using the same converter. There,
A slag level data acquisition unit for acquiring a slag level during the dephosphorization process;
An exhaust gas data acquisition unit for acquiring exhaust gas components and exhaust gas flow rate during the decarburization treatment;
A molten steel data acquisition unit for acquiring a molten steel temperature and a carbon concentration in the molten steel by measuring a sublance during the decarburization process;
Dephosphorization rate using the slag level, the exhaust gas component, the exhaust gas flow rate, the data relating to the molten steel temperature and the carbon concentration, and the operating conditions relating to the dephosphorization treatment, the intermediate waste treatment and the decarburization treatment A constant is calculated, and using the calculated dephosphorization rate constant and the molten iron phosphorus concentration at the start of the dephosphorization process, the phosphorus concentration in the molten steel at the time of the decarburization process after the sublance measurement is estimated. A phosphorus concentration estimation unit;
A converter blowing control device.
The phosphorus concentration estimator is a categorical variable that identifies clusters obtained by time-series clustering performed on a plurality of time-series data of the slag levels acquired in a past operation in the calculation of the dephosphorization rate constant. The converter blowing control apparatus of Claim 4 using this.
6. The converter blowing control apparatus according to claim 4, wherein the phosphorus concentration estimation unit uses an average value of the time series data of the slag level obtained at the time of the dephosphorization process in the calculation of the dephosphorization rate constant. .