WO2017163902A1

WO2017163902A1 - Molten pig iron pre-treatment method and molten pig iron pre-treatment control device

Info

Publication number: WO2017163902A1
Application number: PCT/JP2017/009453
Authority: WO
Inventors: 健岩村; 兼安　孝幸; 太一中江
Original assignee: 新日鐵住金株式会社
Priority date: 2016-03-23
Filing date: 2017-03-09
Publication date: 2017-09-28
Also published as: TWI627284B; JP6547901B2; CN108138246B; KR102133215B1; KR20180052749A; JPWO2017163902A1; TW201734214A; CN108138246A

Abstract

[Problem] To estimate the carbon concentration in molten pig iron after dephosphorization with high precision. [Solution] Provided is a molten pig iron pre-treatment method using a converter furnace comprising: a data-acquiring step for acquiring molten pig iron data relating to molten pig iron before dephosphorization and exhaust gas data including the components of exhaust gas discharged from the converter furnace during dephosphorization and exhaust gas flow rate; and a carbon concentration-estimating step for correcting, using a correction value calculated on the basis of operation factors during the dephosphorization, the decarbonization amount during the dephosphorization calculated on the basis of the exhaust gas data and estimating the carbon concentration after dephosphorization on the basis of the corrected decarbonization amount and the molten pig iron data.

Description

Hot metal pretreatment method and hot metal pretreatment control device

The present invention relates to a hot metal pretreatment method and a hot metal pretreatment control device for estimating a carbon concentration in hot metal after dephosphorization in hot metal pretreatment using a converter.

The converter blowing in the steelmaking process is based on static control and sublance measurement in order to bring the molten steel component concentration (for example, carbon concentration, etc.) and the molten steel temperature to the target values at the time of blowing stop (at the end of decarburization treatment). Blowing control combined with dynamic control is performed. In static control, before starting smelting, based on hot metal data such as component concentration in hot metal, using a mathematical model based on the material balance and heat balance, the molten steel component concentration and molten steel temperature at the time of blowing The amount of blown oxygen and the amount of various auxiliary materials required to bring the target to the target value are determined, and blowing is performed according to this. On the other hand, in dynamic control, during blow smelting, the molten steel component concentration and molten steel temperature are actually measured using a sublance, and based on these measured values, using a mathematical model based on the material balance and heat balance, etc. The blown oxygen amount and the input amounts of various auxiliary materials determined by static control are updated, and blowing is performed using these updated values.

In recent years, a technology called MURC (MUlti Refining Converter) has been developed that can perform hot metal preliminary treatment and decarburization treatment in the same converter in the converter blowing. Yes. In MURC, the dephosphorization process which is one of the hot metal preliminary processes in blowing and the decarburization process in blowing can be performed continuously. Thereby, the heat loss which may arise by transferring a hot metal to another converter in a steelmaking process decreases. Accordingly, since a large amount of scrap can be used for blowing, the production efficiency in the steelmaking process can be remarkably improved.

When a large amount of scrap is charged into the converter, it may remain undissolved in the hot metal after the dephosphorization process is completed. When such unmelted scrap exists, it is difficult to perform the above-described sublance measurement on the hot metal in the converter. This is because the sublance collides with undissolved scrap, which can break the sublance and cause a serious accident. Therefore, when the decarburization process is started after the completion of the dephosphorization, it is difficult to measure the carbon concentration in the hot metal at the start of the decarburization process using a sublance. Therefore, when the dephosphorization process and the decarburization process are continuously performed in the same converter, the static control is not performed based on the actual value of the carbon concentration in the hot metal at the start of the dephosphorization process, not at the start of the decarburization process. It is required to determine the amount of oxygen blown in and the amount of various auxiliary materials charged.

However, depending on the progress of the dephosphorization process, the carbon concentration in the hot metal may be greatly reduced or not significantly reduced from the initial assumption. In this case, the carbon concentration in the molten steel after the decarburization treatment may greatly deviate from the target carbon concentration. Therefore, in order to reliably obtain molten steel having a target carbon concentration, it is necessary to perform static control based on the carbon concentration in the hot metal after the dephosphorization treatment, not before the dephosphorization treatment. Since it is difficult to directly measure the carbon concentration in the hot metal after the dephosphorization treatment, a technique for theoretically estimating the carbon concentration in the hot metal after the dephosphorization treatment is required.

Various technologies have been developed so far for estimating the carbon concentration in converter blowing. For example, in Patent Document 1 below, a parameter regarding decarbonation efficiency is calculated using exhaust gas data discharged from a converter in a decarburization process, and the decarburization process is performed using the parameter in the molten steel. A technique for estimating the carbon concentration is disclosed. In this technique, in the decarburization treatment, the blown oxygen and the carbon in the molten steel are in a ratio of approximately 1: 1 (here, the ratio of 1: 1 corresponds to 1: 1 in the molar ratio). A model is used that combines the behavior in which the decarbonation efficiency is constant at the stage of the decarburization peak period that reacts with the behavior in which the decarbonation efficiency decreases when the carbon concentration in the molten steel falls below the critical value. Yes. Thereby, since the estimation of the carbon concentration reflecting the transition of the decarburization process is possible, the estimation accuracy of the carbon concentration in the molten steel and the molten steel temperature is improved.

JP 2012-1117090 A

However, the carbon concentration in the molten steel estimated by the technique described in Patent Document 1 is merely an estimate of the carbon concentration in the hot metal in the decarburization process. In the dephosphorization process, the oxygen flow rate blown into the converter differs from the decarburization process. Specifically, in the decarburization process, oxygen is blown from the top lance at high speed for decarburization of the molten steel, but in the dephosphorization process, iron oxide slag is generated efficiently to promote dephosphorization. To do so, oxygen is blown at a low speed. When the flow rate of oxygen blown into the converter is different, the mechanism of the oxidation reaction occurring in the converter is also different. Therefore, even if the technique related to the estimation of the carbon concentration disclosed in Patent Document 1 is applied as it is to the estimation of the carbon concentration in the hot metal in the dephosphorization process, the carbon concentration in the hot metal after the dephosphorization process is highly accurate. It is difficult to estimate.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is a novel and improved technique capable of accurately estimating the carbon concentration in hot metal after dephosphorization. Another object is to provide a hot metal pretreatment method and a hot metal pretreatment control device.

In order to solve the above problems, according to one aspect of the present invention, in hot metal preliminary treatment using a converter, hot metal data relating to hot metal before dephosphorization treatment and exhaust gas discharged from the converter during dephosphorization treatment are provided. A data acquisition step for acquiring exhaust gas data including components and exhaust gas flow rate, and a correction for calculating the decarburization amount at the time of dephosphorization processing calculated based on the exhaust gas data based on the operating factors at the time of the dephosphorization processing There is provided a hot metal pretreatment method that includes a carbon concentration estimation step that corrects using a value and estimates a carbon concentration after dephosphorization based on the corrected decarburization amount and the hot metal data.

In the carbon concentration estimation step, the correction value may be calculated by a regression equation having the operation factor as an explanatory variable.

The operation factor during the dephosphorization treatment may include an operation factor indicating the hatching status of the slag during the dephosphorization treatment.

The operation factor indicating the hatching status of the slag may include an operation factor related to acoustic information in the converter.

In the data acquisition step, the target carbon concentration after the dephosphorization process and the amount of oxygen blown into the converter in the decarburization process performed after the dephosphorization process are further acquired. The method may further include an oxygen amount correction step of correcting the blown oxygen amount based on a comparison result of the estimated carbon concentration after the dephosphorization treatment and the target carbon concentration after the dephosphorization treatment.

In order to solve the above problems, according to another aspect of the present invention, in the hot metal pretreatment control apparatus for controlling hot metal pretreatment using a converter, hot metal data relating to hot metal before dephosphorization treatment, A data acquisition unit that acquires exhaust gas data including exhaust gas components and exhaust gas flow rate discharged from the converter during the phosphorus treatment, and a decarburization amount calculated based on the exhaust gas data for the dephosphorization treatment. A carbon concentration estimator that corrects using a correction value calculated based on the operating factor of the time and estimates the carbon concentration after dephosphorization based on the corrected decarburization amount and the molten iron data A hot metal pretreatment control device is provided.

The hot metal preliminary treatment method uses a corrected decarburization amount obtained by correcting the decarburization amount obtained using the exhaust gas data with a correction value expressed by a regression equation with the operating factors during dephosphorization as explanatory variables. Estimate the carbon concentration in the hot metal after phosphorus treatment. Thereby, the carbon concentration in the hot metal after the dephosphorization process can be estimated with high accuracy without performing the sublance measurement after the dephosphorization process. Therefore, it becomes possible to more reliably obtain molten steel having a target carbon concentration after decarburization treatment.

As described above, according to the present invention, it is possible to accurately estimate the carbon concentration in the hot metal after the dephosphorization treatment.

It is a figure showing an example of composition of a hot metal preliminary treatment system concerning one embodiment of the present invention. It is a figure which shows the flowchart of the hot metal preliminary processing method by the hot metal preliminary processing system which concerns on the embodiment. It is a figure which shows the estimation error of decarburization amount ( _{DELTA) Coffgas} based on the waste gas data in a comparative example. Is a diagram illustrating the estimation error of the decarburization amount _ΔC offgas + correction term [Delta] C _correct based on exhaust gas data in the first embodiment. Is a diagram illustrating the estimation error of the decarburization amount _ΔC offgas + correction term [Delta] C _correct based on exhaust gas data in the second embodiment. FIG. 3 is a diagram illustrating an estimation error of a carbon concentration C _deP in Example 1. It is a figure which shows the estimation error of the carbon concentration _CdeP in Example 2. FIG.

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, but in the following explanation, in order to avoid complicated explanation, For convenience, the molten steel will be referred to as molten steel. In addition, the word hot metal is used for the dephosphorization process. In the present specification, “after dephosphorization” is used to mean “when dephosphorization is completed (when dephosphorization is completed)” unless otherwise specified. That is, “after the dephosphorization process” does not include the time point after the start of the decarburization process.

Moreover, although the hot metal pretreatment method according to an embodiment of the present invention assumes that the carbon concentration in the hot metal after the dephosphorization process by MURC is estimated, the present invention is not limited to such an example. For example, the hot metal pretreatment method according to an embodiment of the present invention is a carbon in hot metal after dephosphorization treatment using another converter blowing method such as SRP (Simple Refining Process). It is also possible to estimate the concentration. That is, the hot metal pretreatment method according to one embodiment of the present invention estimates the carbon concentration in the hot metal after dephosphorization regardless of the converter blowing method used for hot metal pretreatment (particularly, dephosphorization). It is possible.

<1. System configuration>
FIG. 1 is a diagram showing a configuration example of a hot metal pretreatment system 1 according to an embodiment of the present invention. Referring to FIG. 1, a hot metal preliminary treatment system 1 according to the present embodiment includes a converter blowing equipment 10, a hot metal preliminary treatment control device 20, and a measurement control device 30.

(Converter blowing equipment)
The converter blowing facility 10 includes a converter 11, a flue 12, an upper blowing lance 13, an exhaust gas component analyzer 101, and an exhaust gas flow meter 102. The converter blowing facility 10 may further include a sound meter 111 and a sound collecting microphone 112. For example, the converter blowing facility 10 starts and stops the supply of oxygen to the hot metal by the top blowing lance 13, inputs the cold material, and converts the converter 11 based on the control signal output from the measurement control device 30. Performs processing related to hot metal and slag drainage. In addition, although illustration is abbreviate | omitted, the converter blowing equipment 10 is a sub lance for measuring the hot metal component density | concentration and hot metal temperature, the acid sending apparatus for supplying oxygen with respect to the top blowing lance 13, and a converter By a general converter, such as a cold material charging device having a drive system for charging a cold material to 11 and an auxiliary material charging device having a drive system for charging an auxiliary material to the converter 11 Various devices used for blowing can be provided.

An upper blowing lance 13 used for blowing is inserted from the furnace port of the converter 11, and oxygen 14 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 15 for stirring the hot metal. In the converter 11, hot metal discharged from the blast furnace, a small amount of iron scrap, a cold material for adjusting the hot metal temperature, and auxiliary raw materials for slag formation such as quick lime are charged / input. When the auxiliary material is powder, it may be supplied into the converter 11 together with the oxygen 14 through the top blowing lance 13.

In the dephosphorization process, as shown in the following formula (1), phosphorus contained in the hot metal chemically reacts with the iron oxide contained in the slag in the converter and the auxiliary raw material containing the calcium oxide-containing material (deoxidation). Phosphorus reaction) Phosphorus is taken into the slag. That is, the dephosphorization reaction can be promoted by increasing the concentration of iron oxide in the slag by blowing. In the following formula (1), “[substance X]” represents the substance X in the hot metal, and “(substance Y)” represents the substance Y in the slag.

Further, 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 generated oxide 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.

Further, in addition to the top blowing lance 13, a sub lance (not shown) can be inserted into the furnace from the furnace port of the converter 11. By immersing the tip of the sublance in molten steel (or hot metal) at a predetermined timing, the component concentration in the molten steel including the carbon concentration, the molten steel temperature, and the like are measured. This measurement of the component concentration and / or molten steel temperature by the sublance is called sublance measurement. The result of the sublance measurement is transmitted to the hot metal preliminary processing control device 20 via the measurement control device 30. In the present embodiment, in the dephosphorization process, unmelted scrap may be present in the converter 11, and thus the sublance measurement is not performed, but the sublance measurement can be performed at a predetermined timing during the decarburization process.

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 analyze and measure exhaust gas at a predetermined sampling period (for example, 5 to 10 (sec) period). The data related to the exhaust gas component analyzed by the exhaust gas component analyzer 101 and the data related to the exhaust gas flow rate measured by the exhaust gas flow meter 102 (hereinafter, these data are referred to as “exhaust gas data”) Is output to the hot metal preliminary processing control device 20 as time series data. The exhaust gas data may be sequentially output to the hot metal preliminary treatment control device 20, or may be output collectively to the hot metal preliminary treatment control device 20 when the dephosphorization processing is completed.

Further, the converter blowing facility 10 may include a sound meter 111 and a sound collecting microphone 112. The sound collection microphone 112 acquires a sound generated from the converter 11 and outputs a signal related to the sound to the sound meter 111. The sound meter 111 performs signal processing on the acquired signal and generates a processing result as acoustic information. The acoustic information generated here is output to the hot metal preliminary processing control device 20 via the measurement control device 30. This acoustic information is information reflecting the hatching state of the slag in the converter 11 during the dephosphorization process, and can be used as a parameter of an operation factor during the dephosphorization process. The operating factors during the dephosphorization process will be described later in detail.

In addition to the sound meter 111 and the sound collecting microphone 112, the converter blowing facility 10 is an apparatus for obtaining operating factor parameters indicating the hatching state of the slag in the converter 11 during the dephosphorization process. May be provided. For example, by irradiating microwaves into the converter 11 and measuring the slag level of the converter 11, the hatching state of the slag can be grasped. When acquiring the said slag level as a parameter of an operation factor, in the converter blowing equipment 10, the microwave irradiation apparatus for irradiating a microwave in the converter 11, for example, the microwave reflected on the molten metal surface is received. And an slag level measuring device for analyzing the slag level based on the microwave received by the antenna.

(Hot metal pretreatment control device)
The hot metal pretreatment control device 20 includes a data acquisition unit 201, a carbon concentration estimation unit 202, a correction amount calculation unit 203, a hot metal pretreatment database 21, and an input / output unit 22. The hot metal preliminary processing 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, a communication device, and the like. Functions of the unit 201, the carbon concentration estimation unit 202, the correction amount calculation unit 203, and the hot metal preliminary processing 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.

In FIG. 1, only the functions characteristic of the present invention among the functions of the hot metal pretreatment control device 20 are mainly illustrated. The hot metal pretreatment control device 20 has a general function required when performing control related to the hot metal pretreatment in addition to the functions shown in the drawing.

For example, the hot metal pretreatment control device 20 has a function of controlling the entire process related to hot metal pretreatment such as blowing oxygen into the converter 11 and charging a cooling material and auxiliary materials. In addition, for example, the hot metal preliminary treatment control device 20 uses a predetermined mathematical model or the like, which is performed in general static control, and uses a predetermined mathematical model or the like, and inputs the amount of oxygen blown into the converter 11 and the cooling material. It has a function of determining an amount (hereinafter referred to as a cold material amount), an input amount of auxiliary materials, and the like. Further, for example, the hot metal preliminary treatment control device 20 has a function of controlling the measurement object, the measurement timing, and the like of the 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 hot metal pretreatment control device 20 estimates the carbon concentration in the hot metal after the dephosphorization treatment using various data stored in the hot metal pretreatment database 21 and the exhaust gas data as input values. Then, the hot metal preliminary treatment control device 20 corrects the indicated values of the blown oxygen amount and the cold material amount determined by the static control before the dephosphorization treatment based on the estimated carbon concentration in the hot metal. The hot metal pretreatment control device 20 further outputs the estimated carbon concentration in the hot metal, and the indicated values of the corrected blown oxygen amount and cold material amount to the input / output unit 22. Moreover, each instruction value output to the input / output unit 22 is output to the measurement control device 30 that controls the operation of the converter blowing facility 10. The measurement control device 30 performs control relating to the feeding of the acid into the converter 11 and the introduction of the cold material according to each indicated value acquired from the hot metal pretreatment control device 20.

Specific functions of each functional unit of the hot metal pretreatment control device 20 will be described later.

The hot metal pretreatment database 21 is a database that stores various data used in the hot metal pretreatment control device 20, and is realized by a storage device such as a storage. As shown in FIG. 1, for example, the hot metal preliminary processing database 21 stores hot metal data 211, parameters 212, target data 213, and the like. These data may be added, updated, changed, or deleted via an input device or a communication device (not shown). Various data stored in the hot metal preliminary processing database 21 are called by the data acquisition unit 201. Moreover, the hot metal preliminary treatment database 21 stores the estimation result by the carbon concentration estimation unit 202 (for example, the carbon concentration in the hot metal after the dephosphorization process) or the correction result by the correction amount calculation unit 203 (for example, correction of the amount of blown oxygen) The later indicated value) may be stored. The storage device having the hot metal preliminary processing database 21 according to the present embodiment is configured integrally with the hot metal preliminary processing control device 20 as shown in FIG. 1, but in other embodiments, the hot metal preliminary processing database 21 is configured. The storage device having the processing database 21 may be separated from the hot metal preliminary processing 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.). The hot metal data 211 includes various other information generally required in hot metal preliminary treatment and decarburization processing (for example, information on the addition of auxiliary raw materials and cold materials (information on auxiliary raw materials and cold material amounts). ), Information on the sublance measurement (information on the measurement target, measurement timing, etc.), information on the insufflated oxygen amount, etc.). The parameter 212 is various parameters used by the carbon concentration estimation unit 202 and the correction amount calculation unit 203. For example, the parameter 212 includes a parameter in a regression equation having an operation factor as an explanatory variable, and a parameter for calculating a correction amount. The target data 213 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 input / output unit 22 has a function of acquiring a correction result such as a carbon concentration estimation result by the carbon concentration estimation unit 202 or a correction value of the blown oxygen amount by the correction amount calculation unit 203 and outputting the result to various output devices. Have. For example, the input / output unit 22 may output the instruction value after correction of the blown oxygen amount acquired from the correction amount calculation unit 203 to the converter blowing facility 10. Thereby, the blowing which reflected the instruction value after correction of the amount of blowing oxygen is performed. Further, the input / output unit 22 may cause the operator to display the estimated carbon concentration in the molten iron or the corrected instruction value of the blown oxygen amount. In this case, the input / output unit 22 may further output to the converter blowing facility 10 information related to an instruction such as acid feeding or cold material input that is input by an operator who has viewed the displayed information. Further, the input / output unit 22 may output an estimation result or the like stored in the hot metal preliminary processing database 21.

(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 controls the charging of the cold material and the auxiliary material to the converter 11 in accordance with an instruction from the hot metal pretreatment control device 20. 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 and the exhaust gas flow meter 102 and transmits the data to the hot metal preliminary treatment control device 20.

<2. Treatment by hot metal pretreatment control device>
Hereinafter, each function of the hot metal pretreatment control device 20 shown in FIG. 1 will be described in order. In the following description, unless otherwise specified, the concentration unit (mass%) of each component is described as (%).

(Data acquisition unit)
The data acquisition unit 201 acquires hot metal data 211, parameters 212 and target data 213 stored in the hot metal pretreatment database 21, and exhaust gas data output from the exhaust gas component analyzer 101 and the exhaust gas flow meter 102. The data acquisition unit 201 may acquire data sequentially measured by the exhaust gas component analyzer 101 and the exhaust gas flow meter 102 during the dephosphorization process or may be acquired collectively after the dephosphorization process. The data acquisition unit 201 outputs the acquired data to the carbon concentration estimation unit 202.

(Carbon concentration estimation part)
The carbon concentration estimation unit 202 estimates the carbon concentration in the hot metal after the dephosphorization process based on various data acquired by the data acquisition unit 201. Hereinafter, a method for estimating the carbon concentration by the carbon concentration estimating unit 202 will be described.

The carbon concentration in the hot metal after the dephosphorization treatment can be estimated from the material balance regarding the carbon in the hot metal before and after the dephosphorization treatment. That is, it is considered that the difference in the mass of carbon contained in the hot metal before and after the dephosphorization treatment coincides with the mass of carbon contained in the exhaust gas generated by the dephosphorization treatment (that is, the material balance is balanced). The present inventors examined using such a material balance model for carbon to estimate the carbon concentration in hot metal after dephosphorization.

First, the mass (decarburization amount) of carbon contained in the exhaust gas generated by the dephosphorization process is calculated based on the exhaust gas data. The decarburization amount ΔC _offgas (ton) based on the exhaust gas data is represented by the following formula (2).

Here, the decarburization amount wc [i] (g / sec) per unit time obtained from the exhaust gas data is calculated by the following equation (3).

Here, CO [i + N] (%) is the CO concentration in the exhaust gas, CO ₂ [i + N] (%) is the CO ₂ concentration in the exhaust gas, and V _offgas [i] (Nm ³ / hr (NTP)) is the total exhaust gas. Flow rate. CO [i] (%) and CO ₂ [i] (%) can be acquired by the exhaust gas component analyzer 101. Further, V _offgas [i] (Nm ³ / hr (NTP)) can be acquired by the exhaust gas flow meter 102. Moreover, i in square brackets [] represents the sampling period by the exhaust gas component analyzer 101 and the exhaust gas flow meter 102. N in square brackets [] corresponds to an analysis delay by the exhaust gas component analyzer 101 (a time delay until the exhaust gas reaches the installation position of the exhaust gas component analyzer 101). A specific value of the analysis delay N may be appropriately determined according to the installation position of the exhaust gas component analyzer 101 in the flue 12 or the like. “NTP” means Normal Temperature Pressure. The value obtained by multiplying V _offgas [i] by 1000 is divided by 3600 in order to convert the unit to (L / sec). Also, the reason why it is divided by 22.4 (L / mol) is to convert it into the number of moles. 12 is the atomic weight of carbon.

On the other hand, the amount of decarburization (hereinafter, the amount of decarburization based on component change) ΔC _c (ton) based on the component measurement results of the carbon concentration in the hot metal before and after the dephosphorization treatment is expressed by the following equation (4). Indicated.

Here, C _HM (%) is the carbon concentration in the hot metal before dephosphorization, W _HM (ton) is the weight of the hot metal before dephosphorization, and C _SC (%) is in the converter 11 before dephosphorization. The carbon concentration in the scrap charged in the reactor, W _SC (ton) is the weight of the scrap charged in the converter 11 before the dephosphorization process, and C _CM (%) is in the cold before the dephosphorization process. The carbon concentration, W _CM (ton) is the weight of the cold water before the dephosphorization treatment, C _{sub, j} (%) is the carbon concentration in the auxiliary raw material j introduced into the converter 11 before the dephosphorization treatment, W _{sub, j} (ton) is the weight of the auxiliary raw material j put into the converter 11 before the dephosphorization process. These actual amounts are included in the hot metal data 211.

C _deP (%) is the carbon concentration in the hot metal after the dephosphorization treatment.

When the material balance regarding carbon before and after the dephosphorization process is balanced, the decarburization amount ΔC _offgas based on the exhaust gas data and the decarburization amount ΔC _C based on the component change can be equal. That is, the relationship between the decarburization amount [Delta] C _C based on the decarburization amount _ΔC offgas and component change based on exhaust gas data is shown as the following equation (5).

From the above, the carbon concentration C _{deP in} the hot metal after the dephosphorization treatment is expressed as the following formula (6) by applying the above formulas (2) to (4) to the above formula (5). Thus, the carbon concentration C _deP in molten iron after the dephosphorization process it is possible to calculate theoretically.

However, the carbon concentration C _{deP in} the hot metal after the dephosphorization treatment based on the exhaust gas data obtained by the above formula (6) is the actual value C _{deP, a of} the carbon concentration obtained from the hot metal sampled after the dephosphorization treatment. The present inventors have found that there is a large deviation from This is because the decarburization amount ΔC _offgas based on the exhaust gas data calculated in the above formulas (2) and (3) includes many errors.

It is considered that the above error is mainly caused by a measurement error by the exhaust gas flow meter 102. When exhaust gas flows through the piping of the exhaust gas flow meter 102, dust such as soot generated from the converter 11 may enter the piping. When such dust adheres to the inside of the pipe (for example, an orifice), the passage of the exhaust gas in the pipe becomes unstable, and the measurement error by the exhaust gas flow meter 102 increases. Since the internal state of the piping of the exhaust gas flow meter 102 changes every moment, it is difficult to suppress the measurement error itself caused by the exhaust gas flow meter 102.

Therefore, as a result of intensive studies by the present inventors, the above equation (5) is incorporated by incorporating a correction term ΔC _correct (ton), which is a correction value for correcting the decarburization amount ΔC _offgas based on the exhaust gas data. and conceived to improve the estimation accuracy of the carbon concentration C _deP in molten iron after the dephosphorization treatment obtained by (6). The above equation (5) is expressed as the following equation (7) by incorporating the correction term ΔC _correct .

The estimation model of the correction term ΔC _correct is constructed by various statistical methods. For example, the correction term ΔC _{correct according} to the present embodiment is an objective variable calculated by a regression equation using various operation factors X as explanatory variables, which is obtained by a known multiple regression analysis method. Specifically, the correction term ΔC _correct is expressed as the following formula (8).

Here, α _k is a regression coefficient corresponding to the k-th operation factor X _k , and α ₀ is a constant. Specific examples of the operation factor X include those 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 correction term ΔC _correct . In addition, all or part of the operation factors included in Table 1 below may be used for estimating the correction term ΔC _correct .

By incorporating the correction term ΔC _correct having the operation factor X _j as an explanatory variable into the mass balance model, the present inventors have improved the estimation accuracy of the carbon concentration C _{deP in} the molten iron after dephosphorization. Found.

Furthermore, as a result of intensive studies by the present inventors, generally considered operating factors at the time of dephosphorization treatment (hot metal amount, hot metal ratio, hot metal temperature, hot metal component, amount of blown oxygen, amount of auxiliary material input, etc., Table 1) In addition to No. 1 to No. N-2 of No. 1), the operating factor reflecting the slag hatching status in the converter 11 during the dephosphorization process is reflected in the correction term ΔC _correct to thereby remove the dephosphorization. The present inventors have found that the estimation accuracy of the carbon concentration _{CdeP in} the hot metal after the treatment is further improved.

The operating factors which reflect the slag formation conditions of the slag can be further improved estimation accuracy of the carbon concentration C _deP in molten iron after the dephosphorization treatment, slag formation condition of slag in the converter 11 during dephosphorization treatment This is thought to reflect decarbonation efficiency. The decarbonation efficiency is an index indicating the efficiency of the reaction between oxygen blown into the converter 11 and carbon in the hot metal. When the blown oxygen touches the hot metal exposed on the hot water surface, a decarburization reaction occurs. However, in the dephosphorization process, phosphorus is preferentially taken into the slag. Therefore, a large amount of slag exists on the surface of the hot metal. Here, depending on the hatching condition of the slag, it is difficult for the blown oxygen to touch the hot metal, so that the decarburization reaction is difficult to occur or even if the blown oxygen is difficult to touch the hot metal, There is a case where the iron oxide becomes an oxygen supply source for the decarburization reaction and the decarburization reaction occurs. Therefore, it is difficult to simply predict whether the decarburization reaction is suppressed or promoted depending on the slag hatching status. However, it is speculated that the slag hatching situation may have some influence on the decarburization reaction. That is, it is considered that the hatching state of the slag in the converter 11 affects the ease of the decarburization reaction, that is, the decarbonation efficiency. Therefore, the operating factor reflecting the slag hatching status is reflected in the correction term ΔC _correct to take into account the effect of the change in the decarbonation efficiency of the converter 11 during the dephosphorization process, and the molten iron after the dephosphorization process. The carbon concentration _{CdeP in the} medium can be estimated. Accordingly, the present inventors that the carbon concentration C _deP estimation accuracy of the molten iron after the dephosphorization process is improved and conceived.

As shown in Table 1, the operating factors that reflect the slag hatching status during the dephosphorization process include, for example, a sound meter value (db) and a measured value (m) of microwave slag height. .

The sound meter value is a value output by the sound meter 111. The sound meter 111 acquires the sound in the converter 11 as an acoustic signal via the sound collection microphone 112 and outputs it as a sound meter value. The sound meter value varies depending on the slag hatching condition in the converter 11. By using the sound meter value as an operation factor, the slag hatching state can be reflected in the correction term ΔC _correct .

The slag level is a value output from a slag level measuring device (not shown). For example, the slag level measuring apparatus acquires the microwave irradiated into the converter 11 via an antenna, and analyzes the slag level from the microwave. The slag level varies depending on the hatching state of the slag in the converter 11. Similar to the sound meter value, the slag hatching state can be reflected in the correction term ΔC _correct by using the slag level as an operation factor.

If the slag hatching status can be grasped by other physical measurement methods, the measurement results obtained by these measurement methods may be used as operation factors. As a result of intensive studies by the present inventors, it has been found that it is preferable to use the sound meter value as an operating factor that reflects the slag hatching status.

In the present embodiment, the estimation model of the correction term ΔC _correct is constructed by multiple regression analysis, but the estimation model may be constructed by other statistical methods. The other statistical method may be, for example, a neural network or a statistical method using a machine learning algorithm such as a random forest.

The estimation method of the correction term ΔC _correct has been described above. The carbon concentration C _{deP in} the hot metal after the dephosphorization treatment is obtained by applying the above formulas (2) to (4) and the above formula (8) to the above formula (7) as shown in the following formula (9). expressed.

The carbon concentration estimation unit 202 estimates the carbon concentration C _deP in the hot metal after the dephosphorization process by substituting various data acquired by the data acquisition unit 201 into the above equation (9). The carbon concentration estimation unit 202 outputs the estimated carbon concentration C _deP to the correction amount calculation unit 203. In addition, the carbon concentration estimation unit 202 may output the estimated carbon concentration C _deP to the input / output unit 22.

(Correction amount calculator)
The correction amount calculation unit 203 is included in the target data 213 based on a comparison result between the carbon concentration C _deP estimated by the carbon concentration estimation unit 202 and the target carbon concentration C _aim after the dephosphorization process included in the target data 213. The amount of oxygen blown in the decarburization process is corrected. The target carbon concentration C _aim after the dephosphorization treatment and the blown oxygen amount O _{2, aim} in the decarburization treatment are amounts determined by static control before the dephosphorization treatment. The correction amount calculation unit 203 calculates the correction amount ΔO _{2, correct} of the blown oxygen amount using the above-described estimation result and the like. Then, the correction amount calculation unit 203 updates the blown oxygen amount O2 _{, aim} initially determined using the correction amount ΔO2 _{, correct} of the blown oxygen amount, and updates the blown oxygen amount O2 _{, corrected} after the update. To get.

The correction amount of the oxygen amount can be calculated by the following equation (10).

Here, β is a parameter. For example, a theoretical value corresponding to the chemical equivalent of oxygen reacting with carbon can be substituted for this parameter. Thereby, the amount of oxygen corresponding to the difference between the estimated carbon concentration C _deP and the target carbon concentration C _aim is calculated.

The correction amount calculation unit 203 outputs information about the _corrected oxygen injection amount O _{2 and corrected} to the input / output unit 22.

It should be noted that the correction amount calculation unit 203 may correct not only the initially determined blowing oxygen amount O _{2, im} but also the initial amount of cold material. For example, when the corrected blown oxygen amount O2 _{, corrected} is smaller than the initially determined blown oxygen amount O2 _{, aim} , the hot metal temperature of the converter 11 can be lowered in the decarburization process. Therefore, the correction amount calculation unit 203 performs a correction to reduce the amount of cold material put into the converter 11 based on, for example, the corrected blown oxygen amount O _{2, corrected} and the hot metal temperature (molten steel temperature). May be. Thereby, even when the amount of oxygen blown in the decarburization process is corrected to be small after the dephosphorization process, the initially determined target molten steel temperature can be reached. The correction amount calculation unit 203 outputs information about the corrected cold material amount to the input / output unit 22.

The configuration example of the hot metal pretreatment system 1 according to the present embodiment has been described above with reference to FIG.

<3. Hot metal pretreatment process flow>
FIG. 2 is a view showing a flowchart of a hot metal preliminary processing method by the hot metal preliminary processing system 1 according to the present embodiment. With reference to FIG. 2, the flow of the hot metal pretreatment method by the hot metal pretreatment system 1 according to the present embodiment will be described. Each process shown in FIG. 2 corresponds to each process executed by the hot metal preliminary process control device 20 shown in FIG. Therefore, the details of each process shown in FIG. 2 are omitted, and only an outline of each process is described.

In the hot metal preliminary processing method according to the present embodiment, first, the data acquisition unit 201 acquires hot metal data and exhaust gas data (step S101). Specifically, the data acquisition unit 201 acquires hot metal data 211, parameters 212, and target data 213 shown in FIG. 1, and exhaust gas data measured by the exhaust gas component analyzer 101 and the exhaust gas flow meter 102.

Next, the carbon concentration estimation unit 202 estimates the carbon concentration in the hot metal after the dephosphorization process based on the acquired various data (step S103). Specifically, the carbon concentration estimation unit 202 estimates the carbon concentration in the hot metal after the dephosphorization process by substituting various data included in the hot metal data and the exhaust gas data into the above equation (9). In the estimation of the correction term ΔC _{correct in} the above equation (9), various operating factors can be selected. For example, in order to further improve the carbon concentration in the hot metal after the dephosphorization treatment, it is preferable to select an operation factor that reflects the slag hatching state in the estimation of ΔC _correct .

Next, the correction amount calculation unit 203 uses the converter 11 in the decarburization process based on the comparison result between the estimated carbon concentration in the hot metal after the dephosphorization process and the target carbon concentration in the hot metal after the dephosphorization process. The amount of oxygen blown in is corrected (step S105). In addition, it is preferable that the amount of cold material during the decarburization process is corrected in order to match the hot metal temperature with the target hot metal temperature after the dephosphorization process in conjunction with the correction of the blown oxygen amount. In addition, the input / output unit 22 issues an instruction to the converter blowing equipment 10 so as to inject oxygen and supply the cold material based on the corrected oxygen amount and cold material amount. The converter blowing facility 10 performs a process relating to the feeding of the acid and the cooling material to the converter 11 according to the instruction.

The processing procedure of the hot metal preliminary processing method according to the present embodiment has been described above with reference to FIG. In the embodiment described above, both the amount of oxygen blown into the converter 11 and the amount of cold material to be injected are corrected based on the estimated carbon concentration in the hot metal after the dephosphorization treatment. The present embodiment is not limited to such an example. For example, in the hot metal pretreatment method according to the present embodiment, only the amount of blown oxygen so that the carbon concentration in the molten steel satisfies the target value may be corrected. In this case, in step S105, based on the estimated carbon concentration in the molten iron after the dephosphorization treatment, only the blown oxygen amount that the carbon concentration in the molten steel satisfies the target value may be calculated.

<4. Summary>
As described above, according to the present embodiment, the corrected decarburization in which the decarburization amount obtained using the exhaust gas data is corrected by the correction value expressed by the regression equation using the operation factor at the time of dephosphorization as an explanatory variable. The amount is used to estimate the carbon concentration in the hot metal after dephosphorization. Thereby, the carbon concentration in the hot metal after the dephosphorization process can be estimated with high accuracy without performing the sublance measurement after the dephosphorization process.

In the estimation of the correction value according to the present embodiment, by using an operation factor that reflects the slag hatching status in the converter 11 as an operation factor, the decarburization efficiency in the converter 11 is set to the correction term described above. It can be reflected. Thereby, the carbon concentration in the hot metal after the dephosphorization treatment can be estimated with higher accuracy.

Furthermore, according to the present embodiment, the amount of oxygen blown in during the decarburization process is corrected using the estimation result of the carbon concentration. By performing the decarburization process based on the corrected oxygen amount, it becomes possible to more reliably obtain molten steel that satisfies the target carbon concentration after the decarburization process. Moreover, it becomes possible to more reliably obtain a molten steel that satisfies the target molten steel temperature after the decarburization process by correcting the amount of cold material put into the converter 11 in accordance with the correction of the amount of blown oxygen. .

The configuration shown in FIG. 1 is merely an example of the hot metal pretreatment system 1 according to the present embodiment, and the specific configuration of the hot metal pretreatment system 1 is not limited to this example. The hot metal pretreatment system 1 only needs to be configured so as to realize the functions described above, and can take any configuration that can be generally assumed.

For example, all the functions of the hot metal preliminary processing control device 20 may not be executed by one device, but 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 carbon concentration estimation unit 202, and the correction amount calculation unit 203 can communicate with other devices having other functions. By being connected, a function equivalent to the hot metal pretreatment 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 hot metal preliminary processing control device 20 according to the present embodiment shown in FIG. 1 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 effectiveness of the correction term obtained by the hot metal pretreatment method according to the present embodiment, the estimation accuracy of the carbon concentration by the hot metal pretreatment method according to the present embodiment, and The application of the hot metal preliminary treatment method according to this embodiment to actual operation was 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.

(Effectiveness of correction term and estimation accuracy of carbon concentration)
First, the effectiveness of the correction term ΔC _correct obtained by the hot metal pretreatment method according to the present embodiment and the estimation accuracy of the carbon concentration C _{deP in} the hot metal after the dephosphorization treatment by the hot metal pretreatment method according to the present embodiment were verified. .

First, in the examples, the decarburization amount ΔC _c based on the component change, the decarburization amount ΔC _offgas and the correction term ΔC _correct based on the exhaust gas data were calculated using the exhaust gas data, the hot metal data, and the operation factors. The decarburization amount ΔC _offgas based on the exhaust gas data was calculated using the above formulas (2) and (3), and the correction term ΔC _correct was calculated using the above formula (8). Further, the decarburization amount ΔC _c based on the component change was calculated using the formula (4). Here, it is assumed that the decarburization amount ΔC _c based on the component change, the decarburization amount ΔC _offgas based on the exhaust gas data, and the correction term ΔC _correct have the relationship of the formula (7).

On the other hand, in the comparative example, the decarburization amount ΔC _c based on the component change and the decarburization amount ΔC _offgas based on the exhaust gas data were calculated using the exhaust gas data and the hot metal data. The calculation method of the decarburization amount ΔC _offgas based on the exhaust gas data and the decarburization amount ΔC _c based on the component change is the same as in this embodiment. Here, the correction term ΔC _correct is not used, and the relationship of the above formula (5) is _assumed between the decarburization amount ΔC _c based on the component change and the decarburization amount ΔC _offgas based on the exhaust gas data.

In Examples and Comparative Examples, the actual value of the carbon concentration in the hot metal sampled from the converter after the dephosphorization treatment is included in C _deP in the above formula (4) in order to verify the effectiveness of the correction term ΔC _correct. Is substituted. That is, in this embodiment, the decarburization amount ΔC _c based on the component change is a value obtained based on the actual value.

Further, an example using no operational factors reflecting the slag formation conditions of the slag to estimate the correction term [Delta] C _correct as Example 1, using the operational factors that reflect the slag formation conditions of the slag to estimate the correction term [Delta] C _correct An example was defined as Example 2. Table 2 shows a list of data and operating factors used in the estimation of the carbon concentration in the hot metal after the dephosphorization treatment in Example 1, Example 2, and Comparative Example. In this example, a sound meter value was used as an operation factor reflecting the slag hatching status.

As an index indicating the effectiveness of the correction term ΔC _correct, the decarburization amount ΔC _offgas (corrected decarburization amount _obtained by adding the correction term ΔC _correct to the exhaust gas data calculated in Example 1, Example 2 and Comparative Example) The error (estimation error) from the decarburization amount ΔC _c based on the component change was calculated, respectively, and the standard deviation σ of the estimation error was obtained. It can be said that as the standard deviation σ is smaller, the estimation error is smaller, that is, the effectiveness of the correction term ΔC _correct is higher.

Moreover, as an index indicating the estimation accuracy of the carbon concentration, the carbon concentration C _deP estimated using the above formula (9) in Example 1 and Example 2, and the hot metal sampled from the converter after the dephosphorization treatment An error from the actual value of the carbon concentration was calculated, and a standard deviation σ of the estimation error was obtained. It can be said that the smaller the standard deviation σ, the smaller the estimation error, that is, the higher the estimation accuracy.

The results are shown in FIGS. FIG. 3 is a diagram illustrating an estimation error of the decarburization amount ΔC _offgas based on the exhaust gas data in the comparative example. FIG. 4 is a diagram showing an estimation error of the decarburization amount ΔC _offgas + correction term ΔC _correct based on the exhaust gas data in the first embodiment. FIG. 5 is a diagram showing an estimation error of the decarburization amount ΔC _offgas + correction term ΔC _correct based on the exhaust gas data in the second embodiment. In each figure, the x-axis shows the decarburization amount based on the actual value obtained by the component analysis of the carbon concentration, and the y-axis shows the decarburization amount based on the exhaust gas data (including the correction term ΔC _correct ).

3 to 5, the standard deviation σ of the estimation error in Comparative Example 1 was 0.80, whereas the standard deviation σ of the estimation error in Example 1 was 0.51. The standard deviation σ of the estimation error in was 0.40. From the result, it can be confirmed that the error of the decarburization amount with respect to the actual data is reduced by the correction by the correction term ΔC _correct . Furthermore, since the standard deviation σ in the second embodiment is smaller than the standard error σ in the first embodiment, it is more effective to incorporate an operation factor that reflects the slag hatching state in the correction term ΔC _correct. It was shown that.

Next, the results regarding the estimation of the carbon concentration after the dephosphorization treatment are shown in FIGS. FIG. 6 is a diagram illustrating an estimation error of the carbon concentration _{CdeP in} the first embodiment. FIG. 7 is a diagram showing an estimation error of the carbon concentration _CdeP in Example 2. In each figure, the x-axis shows the actual value by the component analysis of the carbon concentration, and the y-axis shows the estimated value of the carbon concentration estimated using the hot metal pretreatment method according to the present embodiment.

6 and 7, the standard deviation σ of the estimation error in Example 1 was 0.15, and the standard deviation σ of the estimation error in Example 2 was 0.11. Since all the standard deviations σ are low, it can be said that the estimation accuracy of the carbon concentration C _deP is high. In addition, since the standard deviation σ in Example 2 was smaller than the standard error σ in Example 1, the estimation accuracy of the carbon concentration C _deP can be improved by using an operation factor that reflects the slag hatching status. It was confirmed that it could be further increased.

As described above, it has been found that the carbon concentration C _deP can be estimated with higher accuracy in this example by introducing the correction term ΔC _correct than in the comparative example. In particular, as shown in Example 2, by using the operational factors that reflect the slag formation conditions of the slag to estimate the correction term [Delta] C _correct, it has been found that it is possible to further enhance the estimation accuracy of the carbon concentration C _deP.

(Application to operation)
Next, it was verified whether or not the hot metal preliminary treatment method according to this embodiment can be applied to operations using past operation result data. Specifically, with respect to the past operation result data, the estimation result of the carbon concentration in the hot metal after the dephosphorization treatment obtained by the hot metal pretreatment method according to the embodiment, the amount of injected oxygen during the decarburization treatment, and The correction result of the amount of cold material was verified.

Table 3 is a table showing an application example of the estimation result of the carbon concentration and the correction result such as the oxygen amount to the operation result data. Referring to Table 3, the history of the planned value, the actual value, and the estimated value or the corrected instruction value for each of the carbon concentration in the hot metal, the hot metal temperature, the amount of blown oxygen, and the amount of cold material is shown. The planned value is a value estimated in advance by static control before dephosphorization. The actual value is a value measured or set in the past operation. The estimated value and the corrected instruction value are an estimated value of the carbon concentration obtained by the hot metal pretreatment method according to the present embodiment, and an indicated value of the corrected amount of the blown oxygen amount and the cold material amount. Here, the instruction value for the correction amount of the blown oxygen amount corresponds to, for example _{, the corrected} blown oxygen amount O _{2 and corrected} obtained based on the above formula (10).

Referring to Table 3, due to the static control before the dephosphorization treatment, the carbon concentration in the hot metal at the end of the dephosphorization treatment is 4.0%, and when the sublance is measured during the decarburization treatment, the carbon concentration in the molten steel is 0. It is assumed that the carbon concentration (target carbon concentration) in the molten steel at the end of the decarburization process is 0.1%. Accordingly, the blown oxygen amount is 7.0 Nm ³ / ton at the start of the decarburization process and 25.0 Nm ³ / ton (7. 0 + 18.0), and is determined to be 30.0 Nm ^{3 /} ton (7.0 + 18.0 + 5.0) at the end of the decarburization process. The value of the amount of cold material is 2.0 ton during dephosphorization blowing and 5.0 ton from the start of decarburization treatment to the time of sublance measurement.

However, the carbon concentration in the molten steel at the time of sublance measurement in actual operation was 0.10%. On the other hand, the hot metal temperature at the time of measuring the sublance remained at the planned value of 1600 ° C. As a result, at the end of the decarburization treatment, the carbon concentration in the molten steel was 0.04%, which was lower than the original target carbon concentration. This is presumably because the carbon concentration in the hot metal at the end of the dephosphorization process was lower than the originally determined 4.0%.

On the other hand, according to the hot metal preliminary treatment method according to the present embodiment, the carbon concentration in the hot metal at the end of the dephosphorization process is estimated to be 3.5%. Further, according to this estimation result, the oxygen amount at the time of the sublance measurement from the start of the decarburization process is corrected from 18.0 to 13.0 Nm ³ / ton. Further, the amount of cold material is corrected to 2.5 ton according to the estimation result of carbon concentration and the correction result of oxygen amount. If the operation is performed based on this modification, the carbon concentration at the time of sublance measurement will satisfy the 0.5% previously assumed, so the carbon concentration in the molten steel at the end of the decarburization process should be blown down. It is suggested from the results shown in Table 3 that the target carbon concentration can be made closer to the target carbon concentration. That is, by applying the hot metal preliminary treatment method according to the present embodiment to actual operations, the carbon concentration in the molten steel can be more accurately hit the target carbon concentration.

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 Hot metal preliminary treatment system 10 Converter blowing equipment 11 Converter 12 Flue 13 Upper blowing lance 20 Hot metal preliminary treatment control device 21 Hot metal preliminary treatment database 22 Input / output unit 30 Measurement control device 101 Exhaust gas component analyzer 102 Exhaust gas flow meter 111 Sound meter 112 Sound collection microphone 201 Data acquisition unit 202 Carbon concentration estimation unit 203 Correction amount calculation unit

Claims

In hot metal pretreatment using a converter,
A data acquisition step for acquiring hot metal data relating to hot metal before dephosphorization, and exhaust gas data including exhaust gas components and exhaust gas flow rate discharged from the converter during the dephosphorization process,
The amount of decarburization at the time of dephosphorization calculated based on the exhaust gas data is corrected using a correction value calculated based on the operating factor at the time of dephosphorization, and the corrected amount of decarburization and the molten iron are corrected. A carbon concentration estimation step for estimating the carbon concentration after dephosphorization based on the data;
A hot metal pretreatment method comprising:
The hot metal preliminary treatment method according to claim 1, wherein, in the carbon concentration estimation step, the correction value is calculated by a regression equation having the operation factor as an explanatory variable.
The hot metal pretreatment method according to claim 1 or 2, wherein the operation factor during the dephosphorization treatment includes an operation factor indicating a hatching state of the slag during the dephosphorization treatment.
The hot metal preliminary treatment method according to claim 3, wherein the operation factor indicating the hatching status of the slag includes an operation factor related to acoustic information in the converter.
In the data acquisition step, the target carbon concentration after the dephosphorization process and the amount of oxygen blown into the converter in the decarburization process performed after the dephosphorization process are further acquired,
The oxygen amount correcting step of correcting the blown oxygen amount based on a comparison result of the estimated carbon concentration after the dephosphorization treatment and the target carbon concentration after the dephosphorization treatment, further comprising: The hot metal preliminary treatment method according to any one of the above.
In the hot metal pretreatment control device for controlling the hot metal pretreatment using the converter,
A data acquisition unit for acquiring hot metal data relating to hot metal before dephosphorization, and exhaust gas data including exhaust gas components and exhaust gas flow rate discharged from the converter during the dephosphorization process;
The amount of decarburization at the time of dephosphorization calculated based on the exhaust gas data is corrected using a correction value calculated based on the operating factor at the time of dephosphorization, and the corrected amount of decarburization and the molten iron are corrected. A carbon concentration estimator for estimating the carbon concentration after dephosphorization based on the data;
A hot metal preliminary treatment control device.