JP2019077932A - Methods for determining refining conditions, controlling refining facility, and refining molten iron - Google Patents

Abstract

To provide a method for determining refining treatment conditions, a method for controlling a refining facility, and a method for refining molten iron, to efficiently perform refining treatment and obtain unprecedented refining treatment conditions as well.SOLUTION: This method for determining refining treatment conditions for molten iron 2 to perform refining treatment by injecting refining gas 3 includes numerical analysis of the temporal phenomena in a refining facility (for example, a furnace 11 of a converter 1) based on predetermined initial and termination conditions of a refining treatment, and determination of the refining treatment conditions for the molten iron 2 based on the results of the numerical analysis.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method of determining smelting process conditions, a control method of a smelting facility, and a smelting process method of molten iron.

In the converter, which is a smelting facility, in order to match the component concentration and temperature of the molten steel at the time of blowout when the smelting process is completed, control combining static control and dynamic control based on sublance measurement is performed. (See, for example, Patent Document 1).
Among them, static control is control used from the start of the refining process to the measurement of the component concentration and temperature of molten steel by the sublance at the end of treatment (also referred to as “sublance measurement”). In static control, before starting the refining process, using the mathematical model etc. based on the mass balance and heat balance, the blown oxygen amount and various secondary necessary to bring the component concentration and temperature of the molten steel at the time of blow stop to target values. Raw material inputs are determined. Then, according to the determined processing conditions, processing of molten iron which has not been subjected to decarburization processing is started. The mathematical model used in static control includes the composition and temperature of the hot metal to be charged, the degree of wear and tear of the furnace refractory, the secondary combustion ratio of the exhaust gas, etc., and the material balance, heat balance, thermodynamic calculation, reaction rate calculation It is assembled based on.

On the other hand, dynamic control is control used after the sublance measurement and before blow-off, which is the final stage of the refining process. In the dynamic control, based on the measurement results of the component concentration and temperature of the molten steel by the sublance measurement, the blown oxygen amount determined by the static control and the input amounts of various auxiliary materials are optimized. This can improve the accuracy of the component concentration and temperature of the molten steel at the time of blowout stop. Also, as a matter of course, if the control accuracy of static control is high, the control accuracy of dynamic control is also improved.
The mathematical model used in static control or dynamic control is composed of material balance and heat balance derived from past operation results. In addition, there are some which extract and use the feature quantity from a large amount of operation data (see Patent Document 2).

JP, 2015-101785, A Patent No. 4998661

  As described above, it is difficult to grasp in real time the internal conditions of the refining facility such as the temperature and component concentration of the molten iron during the refining process and the interface shape in the refining facility such as the converter which refines the high temperature molten iron. . For this reason, conventionally, a method for refining processing using static control or dynamic control has been taken. However, in such a method, it has not been possible to predict appropriate refining conditions according to the state of molten iron before refining, and it can not be said that efficient refining is necessarily achieved. . In addition, since the conventional method uses the past refining process conditions and the performance data based thereon, the refining process conditions are determined only by the actual results actually performed in the past, or by interpolation or extrapolation therefrom. I could not

  Therefore, the present invention has been made focusing on the above-mentioned problems, and can perform refining processing efficiently, and can also obtain refining processing conditions which have not been exemplified in the past. It is an object of the present invention to provide a determination method, a control method of smelting equipment, and a method of smelting treatment of molten iron.

  [1] A method of determining a refining process condition when injecting a refining gas to molten iron to perform a refining process, wherein the time lapse inside the refining facility based on the initial condition and ending condition of the refining process set in advance A method of determining a refining process condition comprising: an analyzing process of estimating a mechanical phenomenon by numerical analysis; and a determining process of determining a refining process condition of the molten iron based on a result of the numerical analysis.

[2] In the analysis step, the numerical analysis is performed under a plurality of calculation conditions set based on a plurality of operation conditions, and in the determination step, among the plurality of calculation conditions, calculation results obtained by the numerical analysis Selects the calculation condition that meets the end condition, and determines the operation condition that falls under the calculation condition that meets the condition as the refining treatment condition. How to decide.
[3] In the analysis step, at least a temporal change of the free interface of the molten iron, a temporal change of the free interface of the slag, a chemical reaction between the molten iron and the refining gas, a chemical reaction in the molten iron, The chemical reaction method according to the above [1] or [2], wherein the chemical reaction between the molten iron and the slag is estimated.

[4] After determining the refining process conditions by the method of determining the refining process conditions according to any one of the above [1] to [3], the refining facility is controlled to control the molten iron according to the refining process conditions A control method of a smelting facility characterized by carrying out a smelting process.
[5] When the molten iron is subjected to a refining process by injecting a refining gas to the molten iron to perform the refining process, the method for determining the refining process condition according to any one of the above [1] to [3] A method of smelting treatment of molten iron, comprising smelting the molten iron according to the determined smelting treatment conditions.

  According to the present invention, the smelting process can be efficiently performed, and the smelting process condition determination method, the smelting facility control method, and the smelting process of the molten iron can also obtain the smelting process condition which is not unique in the past. A method is provided.

It is a schematic diagram which shows the converter 1 in one Embodiment of this invention. It is a flow chart which shows a refinement processing method of molten iron concerning one embodiment of the present invention.

  In the following detailed description, numerous specific details are set forth by way of illustrating embodiments of the present invention in order to provide a thorough understanding of the present invention. However, it will be apparent that one or more embodiments may be practiced without such specific details. Also, in the drawings, well-known structures and devices are schematically illustrated for the sake of simplicity.

<Smelting treatment method of molten iron>
A method of smelting treatment of molten iron according to an embodiment of the present invention will be described. In the present embodiment, in the converter 1 which is a refining facility shown in FIG. 1, the molten iron 2 which is the molten metal is decarburized as a refining process to melt a molten steel having a low carbon concentration.
The converter 1 is provided at the bottom of the furnace body 11 with a furnace body 11 which is a smelting vessel provided with a refractory on the inner wall, an upper blowing lance 12 configured to be insertable from above into the opening of the furnace body 11. It is a refinement device which has a plurality of bottom blowing nozzles 13 which were made. In the decarburizing process by the converter 1, the stirring gas 5 which is an inert gas for stirring is blown from the bottom blowing nozzle 13 into the molten iron 2 accommodated inside the furnace body 11, and oxygen from the top blowing lance 12. The molten iron 2 is processed by blowing in the refining gas 3 containing. In addition, on the bath surface of the molten iron 2, the slag 4 which is a liquid phase having a smaller specific gravity than the molten iron 2 is formed by the oxidation reaction by the refining gas, the added auxiliary material and the like.

In the present embodiment, as shown in FIG. 2, first, an analysis step of numerical analysis simulating a phenomenon at the time of refining processing inside the furnace body 11 is performed (S 100). In step S100, a numerical analysis model is created in advance, which simulates the shape of the converter 1, and numerical analysis is performed to estimate the state of the inside of the furnace body 11 over time.
In the numerical analysis of the present embodiment, with the initial condition of the refining process as a starting point, the change over time of the molten iron 2 is determined under a predetermined calculation condition. The initial conditions of the refining process indicate the state of the molten iron 2 immediately after the molten iron 2 is charged into the converter 1. For example, the composition of the molten iron 2, the temperature, the charge amount, and the interface of the molten iron 2 The position of

The composition and temperature of the molten iron 2 are known before being charged into the converter 1. Also, the position of the interface of the molten iron 2 in the converter 1 is one of the initial conditions, but the size and shape of the converter 1 are known in advance, and the position of the interface is also automatic if the amount of charge is determined. Can be
After the initial conditions are determined, numerical analysis is actually performed.
In the numerical analysis, the stirring gas 5 is blown from the bottom blowing nozzle 13, and the refining gas 3 is sprayed from the top blowing lance 12 at a predetermined flow rate and speed to the molten iron 2. Furthermore, the state of the inside of the furnace body 11 is estimated temporally by solving the flow of fluids such as various gases and the molten iron 2 and the slag 4 inside the furnace body 11 by being coupled with various chemical reactions. The various gases are gas components such as CO generated by decarburization reaction and combustion reaction in addition to the refining gas 3 and the stirring gas 5. In addition to the above-mentioned thing, the change of the shape of the surface of molten iron 2 by spraying smelting gas 3, the existence of the occurrence of a splash, etc. are raised to the state inside furnace body 11.

Numerical analysis is performed until the molten iron 2 reaches a predetermined termination condition of the refining process. Here, the specific component composition and temperature of the molten iron 2 can be mentioned as a specific example of the termination condition of the refining process.
There are cases where the numerical analysis results do not completely agree with the refining process termination conditions, but in such a case, it is acceptable to set a tolerance range for the refining processing termination conditions and enter the calculation results within this tolerance range. It is also possible to end the analysis.
However, it is desirable to set an upper limit on the calculation time, since the calculation may not converge and a solution may not be obtained. In the actual refining, the time it takes for the molten iron 2 to be brought to a predetermined position for the next refining after the completion of one refining operation is not so long. In the meantime, numerical analysis must be completed to determine operation conditions, and preparation for refining must be performed, so the upper limit of the calculation time is preferably about 30 minutes or less, and more preferably 10 minutes or less.

As a numerical analysis method for solving the flow of the fluid, any method that can predict the change over time of the free interface and consider the chemical reaction may be used. The free interface is a heterophase interface such as the interface between the gas phase and the slag 4 which is the liquid phase, the interface between the gas phase and the molten iron 2 which is the liquid phase, and the interface between the slag 4 and the molten iron 2. As such a numerical analysis method, for example, a lattice method such as a method of combining a finite volume method and a VoF (Volume of Fluid) method may be used, and SPH (Smoothed Particle Hydrodynamics) or MPS (Moving Particle Semi-implicit) may be used. Etc.) may be used. In addition, the physical model according to the numerical analysis method used is applied to a numerical analysis model.
The chemical reactions to be considered include the oxidation reaction of iron, carbon, etc. in the molten iron 2 at the heterophase interface by the refining gas 3, the oxidation reaction of carbon etc. by oxygen (FeO) in the molten iron 2, the refining shown by the following formula (1) The secondary combustion reaction, which is the reaction between the gas 3 and the generated carbon monoxide (CO) gas, is considered.
2CO + O ₂ → CO ₂ (1)

  As a result, it is possible to predict, as the state in the furnace body 11, the component change of the molten iron 2 at each portion of each phase, the generation state of slag, the generation state of gas by reaction, temperature change and the like. Here, each part is each mesh divided | segmented by discrete processing, when using a lattice method, and is a particle used for calculation in a particle method. And, when predicting the reaction amount of the chemical reaction at the free interface, the area and the shape of the free interface are considered. In the decarburizing treatment in the converter 1, the oxidation reaction of carbon in the molten iron 2 by the refining gas mainly progresses in the vicinity of the recess formed in the free interface by the collision of the jet stream of the refining gas. Therefore, for example, the amount of decarburization, which is the reaction amount of decarburization reaction, is calculated based on the calculation result of the area and shape of the free interface, or the change over time (time fluctuation) of the free interface and the decarburization reaction are linked. By calculating the decarburization amount, the behavior can be estimated more accurately, and the decarburization amount can be estimated more accurately. Furthermore, it is also possible to estimate the generation behavior of the splash, which is the molten iron 2 that has been scattered, by considering the gas-liquid fraction of each mesh when using the grid method and the behavior of each particle when using the particle method. it can.

Further, as described above, estimation of the state inside the furnace body 11 is performed by numerical analysis over time until the end state in which the component concentration and temperature of the molten iron 2 have reached predetermined target values. For example, in step S100, a state after a predetermined time (for example, 10 ^-5 s) has elapsed since the initial condition is estimated by numerical analysis, and thereafter, the state predicted immediately before is assumed to be the initial condition until the processing ends. The estimation of the state after the elapse of a predetermined time is repeatedly performed by numerical analysis, whereby numerical analysis over time is performed.
In step S100, by estimating the internal state of the furnace body 11 by numerical analysis, the processing result in the refining process under the above-described calculation conditions can be obtained. The treatment result indicates various conventional indexes to be evaluated in the refining treatment, and is, for example, an indicator such as decarboxylation efficiency, decarburization rate, treatment time, generation amount of splash, and the like.

In order to estimate the internal state of the furnace body 11 by numerical calculation, predetermined calculation conditions are required. The calculation conditions are set from the operation conditions required when performing the actual refining process. For example, the lance height which is the height from the bath surface of the upper blowing lance 12, the flow rate and velocity of the refining gas 3 injected from the upper blowing lance 12, the flow rate and velocity of inert gas injected from the lower blowing nozzle 13, etc. Can be mentioned. The operation condition and the calculation condition correspond one to one, and when the operation condition is determined, the calculation condition is set in accordance with the operation condition. In actual refining, a plurality of operating conditions are assumed, so the calculation conditions are also set in accordance with the expected number of operating conditions.
In actual refining, the operating conditions may change during the refining, so the calculation conditions should also reflect that. However, depending on the calculation conditions, the molten iron 2 may not reach a predetermined component composition or temperature, or the calculation may not converge and a solution may not be obtained. Such calculation conditions are judged to be unsuitable for operation.

After step S100, based on the result of the numerical analysis in step S100, a determination step of determining the refining process condition of the molten iron 2 is performed (S102). As described above, in step S100, numerical analysis is performed based on a plurality of calculation conditions, and calculation results are obtained respectively. In step S102, among these calculation results, one that satisfies the termination condition of the refining process set in advance is selected.
If there is a calculation condition that matches the termination condition of the refining process, the calculation condition is selected. However, if there are multiple calculation conditions, additional selection conditions are added. The selection conditions can specifically exemplify a plurality of indicators such as decarboxylation efficiency, decarburization rate, treatment time, and amount of generation of splash. Among these indicators, at least one indicator is arbitrarily set as a selection condition according to the purpose. For example, when the selection condition set in advance is such that the decarboxylation efficiency is equal to or more than a predetermined value, the calculation condition having the highest decarboxylation efficiency is selected from a plurality of matching calculation conditions. These selection conditions can be appropriately set in consideration of the steel type, the refining cost, and the like.

Then, the operating conditions corresponding to the selected calculation conditions are determined. This operation condition is the refining process condition when the refining process is actually performed.
The processes of steps S100 and S102 are performed by a computer. This computer performs calculation of the above-mentioned numerical analysis and determination of the refining process conditions by inputting the conditions (component concentration, temperature, etc.) of the molten iron 2 before and after the refining process.

After step S102, a refining process step of actually refining the molten iron 2 in the converter 1 is performed according to the refining process conditions determined in step S102 (S104). The refining process in step S104 is performed by controlling the converter 1 so as to achieve the refining process conditions determined in step S102. The control of the converter 1 may be performed by a computer itself that determines the refining process conditions, or may be performed by a control device connected to the computer. In addition, the refining process in step S104 is performed by controlling the converter 1 according to the refining process conditions displayed on the display device such as a monitor or the like, with the refining process conditions determined in step S102 being displayed. It may be
That is, according to the present embodiment, the refining process conditions are determined by the analysis process of step S100 and the determination process of step S102, and then the converter 1 which is the refining facility is controlled according to the determined refining process conditions. Thus, the molten iron 2 is refined.

  In the past, in order to determine the operating conditions using past refining conditions and actual data based on it, the refining conditions are only actually obtained by the past itself or by interpolation or extrapolation from there. I could not decide. On the other hand, according to the present embodiment, starting from the initial condition of the molten iron 2, it is possible to obtain the state of the molten iron 2 over time by numerical analysis under various calculation conditions, and to obtain the optimum operating condition, As a result, the operating conditions can be obtained even if the conditions have not been achieved in the past.

<Modification>
While the invention has been described with reference to particular embodiments, the description is not intended to limit the invention. Other embodiments of the present invention, including various modifications, as well as the disclosed embodiments, will be apparent to those of ordinary skill in the art by reference to the description of the present invention. Therefore, it is to be understood that the embodiments of the invention described in the claims also encompass the embodiments including the variants described above alone or in combination.

  For example, in the above-mentioned embodiment, although refining equipment presupposed that it is converter 1 which performs decarburization processing, the present invention is not limited to this example. The smelting equipment may be any equipment as long as it smelts and treats the molten iron 2 such as molten iron and molten steel using a gas such as oxygen gas. For example, the smelting facility is a converter-type pretreatment furnace that performs pretreatment before decarburizing treatment such as desiliconization, dephosphorization, and desulfurization of molten iron by blowing a smelting gas containing oxygen into molten iron from the upper blow lance. It may be. The refining facility may be a vacuum degassing apparatus used in the secondary refining process after the decarburizing treatment. In the vacuum degassing apparatus, when melting ultra-low carbon steel etc., decarburization reaction is performed by blowing oxygen gas from the upper blowing lance provided in the vacuum tank to the molten iron circulating in the vacuum tank. I am promoting it. Furthermore, the smelting facility may be a smelting reduction furnace provided with a function of injecting an oxidizing gas from a top blowing lance.

  Furthermore, in the analysis process of the above embodiment, the decarburization reaction and the combustion reaction resulting from it are considered as the chemical reaction that occurs in the refining facility for the sake of simplicity, but the present invention is not limited to this example. The chemical reactions occurring in the refining facility are various, and the chemical reactions to be considered can be arbitrarily set according to the conditions to be considered. For example, in addition to decarburizing reaction and secondary combustion reaction, when decarburizing treatment is carried out in converter 1, in the molten iron 2, the heterophase interface between the molten iron 2 and the slag 4 or the heterophase interface between the molten iron 2 and the gas phase Other reactions that may occur, such as dephosphorization reactions and desiliconization reactions may be considered. In the desiliconization reaction, the silicon in the molten iron 2 is oxidized to become a part of the slag 4, whereby the silicon concentration in the molten iron 2 is reduced. In addition, in the dephosphorization reaction, the phosphorus in the molten iron 2 is oxidized to form a phosphorus oxide, and then the phosphorus oxide forms a compound with CaO in the slag, whereby the phosphorus concentration in the molten iron 2 is reduced. From the viewpoint of prediction accuracy, it is preferable to perform calculation including all elements such as a chemical reaction and movement of a substance, but as the element to be calculated becomes more complicated, the calculation takes more time. Therefore, for elements that are known in advance to be less important, those elements may be omitted.

  Furthermore, in the analysis process and the determination process of the above embodiment, as an example, various operation conditions are fixed as the refining process condition between the start of the refining process and the finishing process, but the present invention is limited to such example I will not. By dividing the period of the refining process into a plurality and performing the analysis step and the determining step in each period, the refining process conditions may be different depending on the period. For example, in the case of decarburizing treatment in which molten steel is melted from molten iron, the period of refining treatment can be divided into two or three depending on the degree of execution of the molten iron pretreatment depending on the difference in decarburization rate. In these periods, the mechanism for determining the rate of decarburization is different, so there may be different optimal operating conditions for improving the rate of decarburization. For this reason, depending on the carbon concentration, the period of the refining process is divided into a plurality, and by performing the analysis step and the determination step in each period, even if the refining condition is changed in which the operation conditions are changed according to the processing time Good.

  Furthermore, although the refining process conditions are determined by performing the analysis process and the determination process immediately before performing the refining process in the above embodiment, the present invention is not limited to such an example. For example, if it is known that the component concentration and temperature of the molten iron 2 before the refining process and the target component concentration and target temperature of the molten iron 2 after the refining process respectively fall within predetermined ranges, these conditions are satisfied. Depending on the analysis process and the determination process, the refining process conditions may be determined in advance. In this case, for example, the conditions of the carbon concentration and temperature of the molten iron 2 before the refining process and the carbon concentration and temperature of the molten iron 2 after the refining process are respectively divided into a plurality of ranges. Next, the refining process conditions that meet the purpose in all combinations of each condition are determined by performing the analysis step and the determination step. Then, when the refining process is performed, these refining process conditions are used as a table, and the final refining process conditions are determined by extracting from the table the refining process conditions that match the conditions of the molten iron 2 before and after the refining process. May be In this way, application can be made regardless of the length of time required for numerical analysis, so application of more complex models is facilitated.

Furthermore, in the above embodiment, although the refining process is performed to the end according to the determined refining process conditions, the present invention is not limited to such an example. For example, the process of measuring the conditions such as the temperature and the component concentration inside the furnace body 11 during the refining process using a measuring method such as the measurement of the concentration of CO and CO ₂ in the exhaust gas and the measurement of the carbon concentration by sublance You may have. In this case, a deviation between the actual result of the prediction result at the measurement time point may be calculated from the measurement result and the prediction result by the numerical analysis, and the refining process condition may be adjusted to correct this deviation. For example, when the prediction result of decarburization rate is lower than the measurement result and the carbon concentration of the molten iron 2 is high, in the processing performed after the deviation is found, the decarburization rate is adjusted to the measurement result, Adjustments such as an increase in gas flow rate and an increase in processing time may be performed.

  Furthermore, although the converter 1 has the configuration shown in FIG. 1 in the above embodiment, the present invention is not limited to such an example. The converter 1 may have any other configuration as long as it has a top blowing lance 12 for injecting a refining gas and is conventionally used for decarburizing the molten iron 2 or the like. For example, instead of the stirring gas 5 which is an inert gas, an oxidizing gas containing oxygen may be blown from the bottom blowing nozzle 13 for the purpose of promoting the oxidation reaction in addition to stirring. In addition to the oxidizing gas, the upper blowing lance 12 may be configured to blow powdery lime and a carrier gas (inert gas or the like) from a nozzle different from the oxidizing gas.

  Furthermore, in the above embodiment, the gas phase and the liquid phase inside the refining facility are considered in the prediction, but the present invention is not limited to this example. For example, in addition to the gas phase and the liquid phase, the solid phase may be considered. In the refining process in the converter 1, various auxiliary materials such as alloy iron and a solvent filler are added for the purpose of component adjustment and promotion of the refining reaction. Such auxiliary materials are added into the furnace body 11 and react with the molten iron 2 and the slag 4 by melting. In addition, scrap serving as an iron source may be added to the furnace body 11 together with the molten iron 2 for the purpose of reducing the production cost of the molten iron 2 and reducing the greenhouse effect gas. For this reason, by incorporating auxiliary materials and scraps as a solid phase into a calculation model and considering melting of the solid phase, chemical reactions after melting, etc., it becomes possible to perform calculation more accurately in actual operation.

  Furthermore, in the above embodiment, as the processing result, for example, various conventional indexes to be evaluated in the refining process, such as decarbonation efficiency, decarburizing speed, processing time, and amount of generation of splash, are used. The present invention is not limited to such examples. The above indicators of treatment results may change in importance due to differences in the environment in which operations are conducted. For example, in an environment where the amount of production is required, an index that greatly contributes to the amount of production, such as the rate of decarburization, the rate of decarburization, and the treatment time, is important. On the other hand, in an environment where production volume is not required so much and there is ample production capacity, it greatly contributes to reduction of usage amount of various gases and auxiliary materials such as decarbonation efficiency and splash generation amount, and improvement of yield. Indicators are important. For this reason, the production cost may be used as a processing result obtained by putting together these indices, and the calculation condition that the production cost is the lowest may be adapted to the processing result. The production cost is the cost of processing the molten iron 2 and can be calculated by summarizing a plurality of indices of the processing result according to the required environment. For example, in the case of an index that contributes to the production amount, the cost change can be calculated according to the increase or decrease of the production amount, and in the case of an index that contributes to the usage amount and yield of the auxiliary material, the auxiliary material, gas, and product The cost can be calculated by using the unit price of steel which is

<Effect of the embodiment>
(1) The method of determining the refining process conditions according to one aspect of the present invention is a method of determining the refining process conditions when the refining process is performed by injecting the refining gas 3 to the molten iron 2, and the preset refining process Based on the result of numerical analysis and analysis process to estimate temporal phenomena of the inside of refining equipment (for example, converter 1) (inside of furnace body 11) by numerical analysis based on initial condition and termination condition of treatment And a determination step of determining the smelting process conditions of the molten iron 2.

  According to the configuration of the above (1), by simulating an internal phenomenon using numerical analysis before the refining process, it is possible to accurately estimate the internal state of the refining device at the time of the refining process. Thereby, according to the state of the molten iron 2, compared with the method using static control or dynamic control, refinement processing conditions which can be performed efficiently can be shown. In addition, in static control, it was necessary to use past operation results when determining the refining process conditions. On the other hand, according to the configuration of the above (1), since it is not necessary to use past operation results when determining the refining processing conditions, efficient processing is possible even under refining processing conditions such as new steel types which have never been done in the past. It can carry out a refining process.

  Furthermore, in the conventional method, it is difficult to directly measure the change in the amount of generation of the splash and the concentration of the component of the molten iron 2 over time in the actual refining process, and it is difficult to evaluate it accurately. However, according to the configuration of the above (1), the internal state of the refining apparatus is simulated and estimated, that is, in order to calculate the behavior, chemical reaction, etc. of the molten iron at the interface as in the above embodiment, It is possible to estimate temporal changes in the generation amount and the component concentration of the molten iron 2. For this reason, it becomes possible to present optimal refining processing conditions for the purpose of reducing the amount of splash generation and increasing the reaction efficiency such as the decarburization efficiency.

(2) In the configuration of the above (1), in the analysis step, numerical analysis is performed under a plurality of calculation conditions set based on a plurality of operation conditions, and in the determination step, numerical analysis is obtained among the plurality of calculation conditions. The calculation condition to be calculated is selected to meet the end condition, and the operation condition corresponding to the calculated condition is determined as the refining process condition.
According to the configuration of the above (2), it is possible to easily determine the refining process condition that conforms to the preset ending condition.
(3) In the configuration of the above (1) or (2), at least the temporal change of the free interface of the molten iron, the temporal change of the free interface of the slag, the chemical reaction between the molten iron and the refining gas The chemical reaction in molten iron and the chemical reaction between molten iron and slag are estimated.
According to the configuration of the above (3), the amount of reaction generated at the free interface of the molten iron 2 can be accurately estimated in accordance with the shape of the molten iron 2, so that the refining process can be performed more efficiently.

(4) A control method of a refining facility according to an aspect of the present invention controls the refining facility after determining the refining process conditions by the method for determining the refining process condition according to any one of the above (1) to (3), The molten iron 2 is refined according to the refining conditions.
(5) The method of smelting treatment of the molten iron 2 according to one aspect of the present invention is the above (1) to (6) when the smelting treatment is performed on the molten iron 2 in a smelting facility that injects the smelting gas 3 onto the molten iron 2 The molten iron 2 is subjected to a refining process according to the refining process conditions determined by any of the methods for determining the refining process conditions of 3).
According to the configurations of the above (4) and (5), the same effect as that of the above (1) can be obtained.

DESCRIPTION OF SYMBOLS 1 converter 11 furnace body 12 upper blowing lance 13 bottom blowing nozzle 2 molten iron 3 refining gas 4 slag 5 stirring gas

Claims (5)

It is a method of determining the refining process conditions when injecting a refining gas to molten iron and performing a refining process,
An analysis step of estimating temporal phenomena inside the refining facility by numerical analysis based on initial conditions and ending conditions of the refining process set in advance;
A determination step of determining a refining process condition of the molten iron based on a result of the numerical analysis;
A method of determining a refining process condition comprising: In the analysis step, the numerical analysis is performed under a plurality of calculation conditions set based on a plurality of operation conditions,
In the determination step, among the plurality of calculation conditions, the calculation result obtained by the numerical analysis selects the calculation condition that meets the end condition, and refines the operation condition corresponding to the calculation condition that is met The method according to claim 1, wherein the method is determined as the processing condition.   In the analysis step, at least a temporal change in the free interface of the molten iron, a temporal change in the free interface of the slag, a chemical reaction between the molten iron and the refining gas, a chemical reaction in the molten iron, and the molten iron The method for determining the refining process conditions according to claim 1 or 2, wherein the chemical reaction with the slag is estimated.   After determining the said refinement processing conditions by the determination method of the refinement processing conditions of any one of Claims 1-3, the said refinement equipment is controlled and the said molten iron is refined according to the said refinement processing conditions. Control method of the smelting equipment. When the molten iron is refined by a refining facility that injects a refining gas into the molten iron and performs refining processing,
A method according to any one of claims 1 to 3, characterized in that the molten iron is subjected to a refining process according to the refining process conditions determined by the method of determining the refining process condition according to any one of claims 1 to 3.

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