JP2021191889A - Converter blowing control device, statistical model construction device, converter blowing control method, statistical model construction method and program - Google Patents

Abstract

To improve a dephosphorization rate of molten iron by charging a CaO source as an auxiliary raw material at an appropriate time.SOLUTION: A converter blowing control device includes a CaO source input determination part for determining the input start time of a CaO source input to molten iron to be blown in a converter, and a blowing treatment control part for starting the input of a CaO source after the elapse of a time assumed to be required from the start of blowing treatment until the basicity in the slag falls below a predetermined threshold in accordance with the determination by the CaO source input determination part.SELECTED DRAWING: Figure 1

Description

The present invention relates to a converter smelting control device, a statistical model construction device, a converter smelting control method, a statistical model construction method and a program.

In the preliminary hot metal treatment using a converter, the dephosphorization treatment is the main purpose. The dephosphorization reaction is expressed by the following formula, and it is necessary to increase the CaO concentration and FeO concentration in the slag in order to promote the reaction. In the formula (1), () means the substance in the slag, and [] means the substance in the hot metal.
3 (CaO) +5 (FeO) +2 [P] = (3CaO · P 2 O 5) +5 [Fe]

Here, the dephosphorization reaction is promoted by increasing the basicity in the slag, that is, the _{ratio of the CaO concentration to the SiO 2} concentration (= (% CaO) / (% SiO _2)). The basicity can be increased by adding quicklime as an auxiliary raw material to the hot metal to increase the CaO concentration in the slag, but increasing the amount of quicklime added increases the operating cost and the amount of slag generated. , There is a limit to the amount of addition. Therefore, Patent Document 1 describes a technique for advancing the dephosphorization reaction under the condition that the amount of quicklime basic unit is small by optimizing the stirring force at the time of dephosphorization treatment in combination with the basicity.

Japanese Unexamined Patent Publication No. 9-1435229

However, the above-mentioned Patent Document 1 does not mention at what point in time the specified basicity is realized. As will be described later, according to the findings of the present inventors, even if the basicity in the slag at one time point during the blowing process is the same in a plurality of operations, the dephosphorization rate may be different. That is, even if the basicity as described in Patent Document 1 is realized at one time during the blowing process, the dephosphorization rate is not always improved.

Therefore, the present invention is a converter blowing control device, a statistical model construction device, and a converter capable of effectively improving the dephosphorization rate of hot metal by adding a CaO source as an auxiliary material at an appropriate time. The purpose is to provide a blowing control method, a statistical model construction method, and a program.

According to a certain viewpoint of the present invention, the blowing process is performed according to the determination by the CaO source charging determination unit for determining the charging start time of the CaO source charged into the hot metal to be blown in the converter and the CaO source charging determination unit. Provided is a converter blowing control device including a blowing process control unit that starts charging a CaO source after a lapse of time that is assumed to be required from the start of slag until the basicity in the slag falls below a predetermined threshold. ..

According to another aspect of the present invention, a data collecting unit that collects hot metal data regarding hot metal that is blown in a converter and operating factor data during the blowing process, and blowing based on hot metal data and operating factor data. Based on the basicity estimation value calculation unit that sequentially calculates the basicity estimation value in the slag in the smelting process and the result of the sequential calculation, the basicity estimation value is a predetermined threshold value from the start of the blowing process using the hot metal data as an explanatory variable. Provided is a statistical model building apparatus including a statistical model building unit that builds a statistical model with a delay time of less than the target variable as an objective variable.

According to still another aspect of the present invention, there is a step of determining the charging start time of the CaO source to be charged into the hot metal to be blown in the converter, and according to the determination, the basicity in the slag from the start of the blowing treatment. Provided is a converter blowing control method including a step of starting charging of a CaO source after the lapse of a time expected to be required for the slag to fall below a predetermined threshold.

According to still another aspect of the present invention, the process of collecting the hot metal data regarding the hot metal to be blown in the converter and the operating factor data during the blowing treatment, and the blowing based on the hot metal data and the operating factor data. The delay time from the start of the blowing process to the time when the estimated basicity falls below a predetermined threshold, using the hot metal data as an explanatory variable, based on the step of sequentially calculating the estimated basicity in the slag in the process and the result of the sequential calculation. A method for constructing a statistical model including a step of constructing a statistical model with the subject variable is provided.

According to still another aspect of the present invention, according to the determination by the CaO source charging determination unit for determining the charging start timing of the CaO source charged into the hot metal to be blown in the converter, and the determination by the CaO source charging determination unit. A computer as a converter smelting control device including a smelting treatment control unit that starts charging a CaO source after the lapse of time estimated to be required from the start of smelting to the time when the basicity in the slag falls below a predetermined threshold. Is provided with a program to make it work.

According to still another aspect of the present invention, based on the hot metal data and the operating factor data, the data collecting unit which collects the hot metal data about the hot metal to be blown in the converter and the operating factor data during the blowing process, and the hot metal data and the operating factor data. Based on the basicity estimation value calculation unit that sequentially calculates the basicity estimation value in the slag in the blowing process and the result of the sequential calculation, the basicity estimation value is determined from the start of the blowing process using the hot metal data as an explanatory variable. A program for operating a computer as a statistical model construction device including a statistical model construction unit for constructing a statistical model with a delay time until it falls below a threshold variable as an objective variable is provided.

With the above configuration, the addition of the CaO source as an auxiliary raw material is started after a predetermined time has elapsed from the start of the blowing process. As a result, the transition of the basicity in the slag can be brought close to the pattern when the dephosphorization rate is high, and as a result, the dephosphorization rate of the hot metal can be effectively improved.

It is a figure which shows the schematic structure of the refining equipment including the converter blowing control device which concerns on 1st Embodiment of this invention. It is a flowchart which shows the process of the converter blowing control method which concerns on 1st Embodiment of this invention. It is a conceptual diagram of a composite reaction model. It is a graph which shows the basicity estimation value of the operation which had a relatively high dephosphorization rate in time series. It is a graph which shows the basicity estimation value of the operation which the dephosphorization rate was relatively low in time series. It is a figure which shows the result of clustering the transition pattern of the basicity estimated value in a blowing process. It is a figure which shows the result of clustering the transition pattern of the basicity estimated value in a blowing process. It is a figure which shows the result of clustering the transition pattern of the basicity estimated value in a blowing process. It is a figure which shows the result of clustering the transition pattern of the basicity estimated value in a blowing process. It is a figure which shows the result of clustering the transition pattern of the basicity estimated value in a blowing process. It is a figure which shows the result of clustering the transition pattern of the basicity estimated value in a blowing process. It is a figure which shows the result of clustering the transition pattern of the basicity estimated value in a blowing process. It is a figure which shows the distribution of the dephosphorization rate in each cluster shown in FIGS. 6A to 6G. It is a flowchart which shows the process of the converter blowing control method which concerns on the modification of 1st Embodiment of this invention. It is a figure which shows the schematic structure of the refining equipment including the converter blowing control device which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the process of the converter blowing control method which concerns on 2nd Embodiment of this invention. It is a figure which shows the schematic structure of the refining equipment including the statistical model construction apparatus which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the process of the statistical model construction method which concerns on 2nd Embodiment of this invention.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, and duplicate description will be omitted.

(Outline of equipment)
FIG. 1 is a diagram showing a schematic configuration of a refining facility including a converter blowing control device according to a first embodiment of the present invention. As shown in FIG. 1, the refining equipment 1 includes a converter equipment 10, a measurement control device 20, and a converter blowing control device 30. Hereinafter, each part will be further described.

The converter equipment 10 includes a converter 11, a top blowing lance 12, a flue 13, a tuyere 14, and a charging device 15. In the converter equipment 10, the top blowing lance 12 inserted from the furnace opening of the converter 11 supplies oxygen gas 121 to the hot metal 111 in the converter 11. In the decarburization treatment of the primary refining, the carbon in the hot metal 111 reacts with the oxygen gas 121 _{to become CO gas or CO 2} gas, and these gases are discharged via the flue 13. The hot metal 111 that has undergone the decarburization treatment is sent to the next process as molten steel 112. Further, in the decarburization treatment, phosphorus and silicon in the hot metal 111 also react with the oxygen gas 121 or the auxiliary raw material contained in the slag 113, and are taken into the slag 113 to be stabilized. On the other hand, a bottom-blown gas 141 such as nitrogen gas or argon gas is blown from the tuyere 14 to stir the hot metal 111 and promote the above reaction. The charging device 15 loads the auxiliary raw material 151 into the converter 11. The auxiliary material 151 contains a CaO source such as quicklime and an oxygen-containing auxiliary material such as iron ore. A powdery auxiliary material blown together with the oxygen gas 121 using the top-blown lance 12 may be used as in the case of powdered quicklime described later. In the present specification, the timing of starting the addition of the auxiliary raw material including the CaO source, or the amount of the auxiliary raw material, is not limited to the case where the bulky auxiliary material is charged by the charging device 15, and the powdery auxiliary material is top-blown lance 12. It is also included in the case of blowing using.

The measurement control device 20 executes various measurements related to the refining process in the converter facility 10 and controls the refining process. Specifically, the measurement control device 20 includes a sublance 21, an exhaust gas analyzer 22, and an exhaust gas flow meter 23 as a measurement system. The sublance 21 is inserted from the furnace opening of the converter 11 together with the top blown lance 12, and the measuring device provided at the tip thereof is immersed in the molten steel 112 at a predetermined timing during the decarburization treatment, whereby the molten steel 112 containing a carbon concentration is contained. (The carbon concentration in the molten steel is referred to as the molten steel carbon concentration), the temperature of the molten steel 112 (also referred to as the molten steel temperature), and the like are measured. Such a measurement using the sublance 21 is also referred to as a sublance measurement in the following description. The exhaust gas analyzer 22 analyzes the components of the gas discharged via the flue 13. Specifically, the exhaust gas analyzer 22 _{measures the concentrations of CO, CO 2} and O ₂ contained in the exhaust gas (the concentration of each component is referred to as the exhaust gas component concentration). On the other hand, the exhaust gas flow meter 23 measures the flow rate of the gas discharged through the flue 13 (referred to as the exhaust gas flow rate). The result of the above sublance measurement and the measurement result of the exhaust gas analyzer 22 and the exhaust gas flow meter 23 are transmitted to the converter blowing control device 30.

On the other hand, the measurement control device 20 includes a lance drive device 24, a blow control device 25, a bottom blow gas supply device 26, and an input control device 27 as a control system. The lance drive device 24 drives the top blow lance 12 in the vertical direction. Thereby, the height of the top blown lance 12, that is, the distance from the hot metal 111 at the position where the oxygen gas 121 is supplied in the converter 11 can be adjusted. The blow control device 25 controls the flow rate of the oxygen gas 121 supplied to the top blow lance 12. Further, the blowing control device 25 may control the flow rate of powdery auxiliary materials such as powdered quicklime supplied to the top blowing lance 12 together with the oxygen gas 121. The bottom-blown gas supply device 26 controls the flow rate of the bottom-blown gas 141 supplied to the tuyere 14. The charging control device 27 controls the charging timing and the charging amount of the auxiliary raw material 151 by the charging device 15. The operation of the lance drive device 24, the blow control device 25, the bottom blow gas supply device 26, and the input control device 27 may be controllable according to a control signal from the converter blow control device 30.

The converter blowing control device 30 is implemented by a device including a communication unit 31, a calculation unit 32, a storage unit 33, and an input / output unit 34, for example, a computer. The communication unit 31 is various communication devices that communicate with each element of the measurement control device 20 by wire or wirelessly, receives the measurement result obtained by the measurement control device 20, and transmits a control signal to the measurement control device 20. do. The arithmetic unit 32 is an arithmetic unit that executes various arithmetic operations according to a program. The arithmetic unit includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The program is stored in the ROM of the arithmetic unit or the storage unit 33. By operating according to the program, the calculation unit 32 functions as a basicity estimation value calculation unit 321, a CaO source input determination unit 322, and a blowing process control unit 323. The storage unit 33 is a storage capable of storing various types of data. In the present embodiment, the storage unit 33 contains the hot metal data 331 related to the hot metal 111 to be blown in the converter 11, the operation factor data 332 during the blowing process, and the base extracted from the results of the past blowing process. The degree transition pattern 333 is stored. The input / output unit 34 includes an output device such as a display or a printer, and an input device such as a keyboard, a mouse, or a touch panel. The output device outputs, for example, information such as the input start timing of the CaO source determined by the CaO source input determination unit 322. The input device acquires, for example, an instruction input regarding the control executed by the blowing process control unit 323. The arithmetic unit may be a PLC (Programmable Logic Controller) or may be realized by dedicated hardware such as an ASIC (Application Specific Integrated Circuit).

Here, the operation factor data 332 stored in the storage unit 33 is, for example, the component concentration of the molten steel 112, the temperature of the molten steel 112, and the exhaust gas obtained by the measurement using the sublance 21 of the measurement control device 20 during the blowing process. The exhaust gas component concentration measured by the analyzer 22, the exhaust gas flow rate measured by the exhaust gas flow rate system, the height of the top blow lance 12 controlled by the lance drive device 24, the amount of blown oxygen supplied by the blow control device 25, and the bottom blow. It includes the flow rate of the bottom blown gas supplied by the gas supply device 26, and at least a part of the charging start timing and the charging amount of the auxiliary raw material by the charging control device 27 or the blowing control device 25.

In the converter blowing control device 30 described above, the basicity estimation value calculation unit 321 uses the composite reaction model described later to start the blowing process from the hot metal data 331 read from the storage unit 33 and the operation factor data 332. The estimated value of basicity in the slag 113 is sequentially calculated. The CaO source charging determination unit 322 determines whether or not it is time to start charging the CaO source to be charged into the hot metal 111 as an auxiliary raw material. Specifically, in the present embodiment, when the basicity estimation value sequentially calculated by the basicity estimation value calculation unit 321 falls below a predetermined threshold value in the CaO source input determination unit 322 after the start of the blowing process ( For example, when it falls below the limit for the first time) is determined as the time to start charging the CaO source. In the example of the present embodiment, the blowing process control unit 323 is a CaO source input determination unit after the lapse of time that is assumed to be required from the start of the blowing process until the basicity in the slag falls below a predetermined threshold value. When it is determined by 322 that it is time to start charging, the CaO source is started to be charged. Further, in the present embodiment, the blowing process control unit 323 has a base in which the basicity estimation value sequentially calculated by the basicity estimation value calculation unit 321 is stored in a predetermined time-series pattern, specifically, the storage unit 33. The input amount of the CaO source is controlled so as to change according to the degree transition pattern 333. The blowing process control unit 323 transmits a control signal to the blowing control device 25 or the injection control device 27 via the communication unit 31, and the injection control device 27 or the blowing control device 25 that has received the control signal outputs the CaO source. Will be executed.

In the above example, the fact that the input start time is determined by the CaO source input determination unit 322 is output to the user via the input / output unit 34, and the instruction input input by the user via the input / output unit 34 is performed. The blowing process control unit 323 may start inputting the CaO source according to the above. Alternatively, the blowing process control unit 323 may automatically start charging the CaO source when the CaO source charging determination unit 322 determines that the charging start time is reached.

(Outline of process)
FIG. 2 is a flowchart schematically showing the process of the converter blowing control method according to the first embodiment of the present invention. In the illustrated example, after the start of the blowing process in the converter 11 (step S11), the basicity estimation value calculation unit 321 of the converter blowing control device 30 uses the composite reaction model described later in the slag 113. The estimated value of basicity of is sequentially calculated (step S12). At this time, the basicity estimation value calculation unit 321 receives the hot metal data 331 that has been measured in advance and stored in the storage unit 33, and the operation factor data 332 that is sequentially acquired during the blowing process and stored in the storage unit 33. Use. Next, the CaO source input determination unit 322 determines whether or not the basicity estimated value is below a predetermined threshold value (step S13). If the estimated basicity value does not fall below a predetermined threshold value, the sequential calculation of the estimated basicity value (step S12) is continued.

If the estimated basicity value is below a predetermined threshold value in the determination in step S13, the CaO source charging determination unit 322 determines that time as the CaO source charging start time, and the blowing process control unit 323 determines the hot metal 111. The injection of the CaO source into the (step S14) is started. Even after the start of charging the CaO source (step S14), the basicity estimation value calculation unit 321 continuously calculates the basicity estimation value in the slag 113 using the combined reaction model (step S15), and the blowing process control unit. 323 controls the input amount of the CaO source so that the estimated basicity value changes according to the basicity transition pattern 333 stored in the storage unit 33 (step S16). For example, the blowing process control unit 323 reduces the input amount of the CaO source if the estimated basicity value is higher than the value of the basicity transition pattern 333, and the estimated basicity value is lower than the value of the basicity transition pattern 333. For example, the input amount of the CaO source is increased. The process of step S15 and step S16 may be repeatedly executed until the end of the blowing process (step S17).

After the lapse of time that is assumed to be required from the start of the blowing process in the converter 11 to the time when the basicity in the slag falls below a predetermined threshold value by the above-mentioned process, in the example of the present embodiment, the slag 113 is used. When the estimated value of basicity falls below a predetermined threshold value, the CaO source is charged into the hot metal 111. As described above, the basicity in the slag affects the progress of the dephosphorization reaction, and the higher the basicity, the more the dephosphorization reaction is promoted. In addition, maintaining a high basicity by adding a CaO source from the initial stage of the blowing process does not necessarily contribute to the improvement of the dephosphorization rate. In the present embodiment, the basicity in the slag is lowered without adding the CaO source at the initial stage of the blowing treatment, and when the basicity falls below a predetermined threshold value, the CaO source is added to increase the basicity. Thereby, the CaO source can be effectively used to improve the dephosphorization rate.

(Composite reaction model for sequentially calculating estimated basicity in slag)
Here, a composite reaction model for sequentially calculating the estimated basicity in slag, which is described in JP-A-2018-95943 and the like, will be further described. FIG. 3 is a conceptual diagram of a combined reaction model. The combined reaction model includes (a) a hot spot reaction, which is an oxidation reaction between blown oxygen (oxygen gas 121) and hot metal 111 in the converter 11, and (b) hot metal 111 excluding the region where the hot spot reaction proceeds. It is a model of the slag metal interface reaction, which is the reaction in the interface region with the slag 113. In this combined reaction model, the slag metal interfacial reaction is described in, for example, S. Ohguchi et. Al, “Simultaneous dephosphorization and desulphurization of molten pig iron”, Ironmaking and Steelmaking, 1984, Vol. 11, No. 4, p. 41. Represented by a competitive reaction model.

(Fire point reaction model)
First, a mathematical model that expresses the fire point reaction will be described. In the fire point region, oxygen is supplied to the hot metal from a top blown lance or the like, so that an oxidation reaction (fire point reaction) of Si, C, and Fe contained in the hot metal occurs. The mass balances of Si, C, and Fe in the fire point reaction are represented by the following formulas (1) to (3).

Here, in the above formulas (1) to (3), [Si] _f , [C] _f , and [Fe] _f are the Si concentration (%), C concentration (%), and C concentration (%) of the hot metal in the hot spot region. Fe concentration (%), [Si], [C], and [Fe] are the Si concentration (%), C concentration (%), and Fe concentration (%), k _{Si of the hot metal in the region other than the hot spot region.} Desiliconization reaction rate constant (% / sec), ΔC is the decarburization rate (% / sec) obtained from the exhaust gas data, ΔFe is the iron oxidation rate (% / sec) obtained from the exhaust gas data, and V _f is the fire point region. The volume of hot metal (m ³ ) and Q in the above are the recirculation amount of hot metal in the converter (m ³ / sec).

The decarburization rate ΔC obtained from the exhaust gas data is calculated from the following equation (4) using the measurement data of the exhaust gas analyzer 22 and the exhaust gas flow meter 23. In formula (4), _Qoffgas is the exhaust gas flow rate (Nm ³ / hr) _{measured by the exhaust gas flow meter 23, and b g} (CO) and b _g (CO ₂ ) are in the exhaust gas measured by the exhaust gas analyzer 22. The CO concentration (%), the CO ₂ concentration (%), and W _f are the weights (tons) of the hot metal in the hot spot region.

_{When cheaper limestone (calcium carbonate: CaCO 3} is the main component) is used instead of quicklime (calcium oxide: CaO as the main component) as the CaO source that promotes the dephosphorization reaction, the hot metal is removed. and CO ₂ generated by the coal reaction, the slag formation reactions calcium carbonate following expression be calculated more accurately decarburization rate ΔC by distinguishing and CO ₂ generated by the _{(CaCO 3 → CaO + CO 2} ) (5) , May be used instead of equation (4). In the formula (5), ΔW _CaCO3 is the limestone slag rate (ton / sec). For example, in the following formula (6), the _{time constant T CaCO3} assuming a first-order delay with respect to _{the input amount W CaCO3} of the limestone is 60. Calculated as (sec). It is a coefficient of [Delta] W _CaCO3 -0.12 is a constant determined stoichiometrically from the reaction formula _{(CaCO 3 → CaO + CO 2} ).

The iron oxidation rate ΔFe obtained from the exhaust gas data is consumed in the decarburization reaction and the desiliconization reaction from _{the oxygen amount FO 2} (Nm ³ / hr) supplied to the hot metal in the converter in the following formula (7). It is calculated using the amount of oxygen obtained by subtracting the amount of oxygen obtained. However, when the value on the right side of the equation (7) is smaller than 0 as shown in the equation (8), ΔFe = 0 is set.

On the other hand, the change in the concentration of Si and Fe oxidized in the fire point region corresponds to the change in the concentration _{of SiO 2 and FeO in the slag due to the fire point reaction.} This is because Si and Fe reduced by the oxidation reaction in the fire point region _{are changed to SiO 2} and FeO and incorporated into the slag. Therefore, the concentration change (% / sec) of SiO2 and FeO in the slag due to the fire point reaction is represented by the following formulas (9) and (10) from the above formulas (1) and (3). In the formulas (9) and (10), <SiO ₂ > _f and <FeO> _{f are the SiO 2} concentration (%) and FeO concentration (%) in the slag generated in the fire point region, _{and WS} is the weight of the slag. (Ton).

Further, the heat balance equation in the fire point region can be expressed as the following equation (11) in consideration of each reaction heat generated in the fire point reaction. In the formula (11), cp _f is the specific heat (J / (kg · ° C.)) of the hot metal in the hot spot region. T _f is the temperature of the hot metal in the hot spot region (° C.), H _{reac, f} is the heat of reaction (J / sec) in the hot spot region, for example, [Si] _f , [C] _f , and [Fe] _f . Calculated using. RQ is the amount of heat flowing into the fire point region (J / sec) due to reflux in the converter, and is calculated using, for example, the hot metal temperature T (° C.) in a region other than the fire point region. RQ _f is the amount of heat outflow (J / sec) from the hot spot region due to reflux in the converter, and is _{calculated using, for example, the hot metal temperature T f} (° C.) in the hot spot region.

Generated by the behavior of the hot metal component in the slag region and the slag reaction by the above equations (1) to (3), equation (4) or equation (5), equations (7) to (11). _{The behavior of oxides (SiO 2} and FeO) flowing into the slag can be expressed.

(Slag metal interface reaction model)
Next, the slag metal interfacial reaction will be described. The reaction on the hot metal component at the slag metal interface is expressed by mass transfer driven by the difference between the equilibrium concentration of the hot metal component at the slag metal interface and the concentration of the hot metal component outside the fire point region. Specifically, the mass balance of the elements X _i contained in the hot metal in the slag metal interface is represented by the following formula (12). In this embodiment, {X _i } = {C, Si, Mn, P, Fe}. In the formula (12), [X _i ] is the element X _i concentration (%) of the hot metal in the region other than the hot spot region, V is the volume of the hot metal in the region other than the hot spot region (m ³ ), and A is the slag metal interface. Area (m ² ), K _Xi is the mass transfer coefficient of element X _i (m / sec), [X _i ] ^* is the equilibrium concentration (%) of _{element X i} contained in the hot metal at the slag metal interface _{, [X i} ] _{F is the element X i} concentration (%) of the hot metal in the fire point region _{, and W Xi and SUB} are the input terms (% / sec) for considering the increase of the _{element X i} which is the hot metal component due to the input of the auxiliary raw material. be.

Here, the equilibrium concentration [X _i ] ^* _{of the element X i} contained in the hot metal at the interface of the slag metal is expressed using ^{the interfacial oxygen concentration ao *} described in the above-mentioned document of S. Ohguchi et al. The interfacial oxygen concentration ao ^* is calculated from the oxygen balance equation at the slag metal interface.

On the other hand, the reaction related to the slag component at the slag metal interface is also expressed by mass transfer driven by the difference between the equilibrium concentration of the slag component at the slag metal interface and the concentration of the component in the bulk of the slag, similar to the reaction related to the hot metal component. Will be done. _{Specifically, the mass balance of the oxide XO j} contained in the slag at the slag metal interface is represented by the following formula (13). In this embodiment, {XO _j } = {CaO, SiO ₂ , FeO, MnO, P ₂ O ₅ , Al ₂ O ₃ }. In the formula (13), <XO _j> is the concentration of oxides XO _j contained in slag (%), VS slag volume ^(m _{3), K XOj} mass transfer coefficient of the oxide XO _j (m / sec ), <XO _j > ^* is the equilibrium concentration (%) of _{oxide XO j} contained in slag, _{and W XOj, SUB is the oxide XO j} contained in slag due to the addition of auxiliary materials such as quicklime, limestone, and scale. It is an input term (% / sec) for considering the increase.

Note that <SiO ₂ > and <FeO> are represented by the following equations (14) and (15) in which the production rates _{of SiO 2} and FeO in the fire point reaction are added to the right side of the equation (13). This makes it possible to express the change in the concentration of the slag component due to the inflow of the oxide produced by the fire point reaction into the slag.

Further, the heat balance of the hot metal portion constituting the slag metal interface reaction and the heat balance of the slag portion are represented by the following equations (16) and (17) in consideration of the heat of reaction such as the slag metal interface reaction. To. In the formula (16), W is the weight of the hot metal in the region other than the fire point region (ton), cp is the specific heat of the hot metal in the region other than the fire point region (J / (kg · ° C)), and T is other than the fire point region. The temperature (° C) of the hot metal in the region of. H _reac is the reaction heat (J / sec) distributed to the hot metal among the reaction heat generated in the slag metal interfacial reaction, and is calculated based on the mass transfer of each component accompanying the slag metal interfacial reaction. _QSUB is the amount of heat removed (J / sec) generated by the dissolution of the auxiliary material in the hot metal. In the formula (17), cp _S slag specific heat (J / (kg · ℃) ), T S is the temperature of the slag (° C.). H _{reac and S} are reaction heats (J / sec) distributed to the slag among the reaction heats generated in the slag metal interface reaction, and are calculated based on the mass transfer of each component accompanying the slag metal interface reaction. RQ _S is the amount of heat removed from the slag surface (J / sec).

From the above equations (12) to (17), the behavior of the hot metal component and the slag component at the slag metal interface including the behavior of the hot metal component due to the fire point reaction can be expressed.

The basicity estimation value in the slag can be sequentially calculated by the combined reaction model in which the fire point reaction model and the slag metal interface reaction model as described above are combined. Specifically, by solving the simultaneous equations of equations (1) to (3), equation (4) or equation (5), and equations (7) to (17), the CaO concentration in the slag and SiO ₂ The concentration can be estimated, and the basicity estimated value CS can be calculated by the following equation (18).

(Relationship between basicity transition and dephosphorization rate)
Here, according to the findings of the present inventors, there is a relationship as described below between the transition of basicity in slag and the dephosphorization rate.

FIG. 4 is a graph showing the estimated basicity calculated using the above-mentioned combined reaction model in chronological order in an operation in which the dephosphorization rate was relatively high (80% or more). As shown in the graph, in the operation in which the dephosphorization rate was relatively high, the estimated basicity value decreased at the initial stage of blowing to a minimum value of about 0.5, and then increased. On the other hand, FIG. 5 is a graph showing the estimated basicity calculated using the combined reaction model in chronological order in the operation in which the dephosphorization rate was relatively low (60% or less). As shown in the graph, in the operation in which the dephosphorization rate was relatively low, the estimated basicity value did not reach the minimum value at the initial stage of blowing, but decreased to about 1.5 and remained flat.

From the above findings, it is considered that there is a correlation between the transition pattern in which the estimated basicity value decreases to a minimum value below a predetermined threshold and then increases in the initial stage of blowing, and the high dephosphorization rate. .. That is, for example, rather than adding a CaO source from the initial stage of blowing to maintain a high level of basicity (example in FIG. 5), the basicity is lowered without adding a CaO source at the initial stage of blowing, and then the basicity is lowered. It can be said that it is more likely that the dephosphorization rate can be improved by adding a CaO source to the solution to increase the basicity (example in FIG. 4).

Therefore, in the present embodiment, the blowing process control unit 323 determines, for example, that the CaO source is input after the lapse of time that is assumed to be required from the start of the blowing process until the basicity in the slag falls below a predetermined threshold value. When it is determined by the unit 322 that it is time to start charging, the CaO source is started to be charged. As a result, it is considered that the time-series change in basicity approaches the example shown in FIG. 4, and the dephosphorization rate can be improved. The threshold value of the basicity estimation value that serves as a criterion for determining the timing of starting the injection of the CaO source by the CaO source injection determination unit 322 can be, for example, 0.5 from the above example of FIG.

6A to 6G are diagrams showing the results of clustering the transition patterns of the estimated basicity values in the blowing process. In the illustrated example, it is obtained as a result of clustering the transition pattern of the basicity estimation value sequentially calculated using the composite reaction model from the start of blowing to the lapse of 400 seconds in the past 3000 operations by unsupervised learning. Seven clusters (No. 1 to No. 7) are shown. The thick lines shown in the respective figures of FIGS. 6A to 6G represent the average value of the transition of the basicity estimation values included in each cluster.

FIG. 7 is a diagram showing the distribution of dephosphorization rate in each cluster shown in FIGS. 6A to 6G. The distribution of dephosphorization rate is shown as a box plot. As shown in the figure, among the seven clusters, the hot metal dephosphorization rate is the highest distributed in No. 6D. 4 clusters (corresponding to the example shown in FIG. 4 above).

Therefore, in the present embodiment, the blowing process control unit 323 starts charging the CaO source according to the determination by the CaO source charging determination unit 322, and then the basicity estimated value is No. 1 shown in FIG. 6D. The input amount of the CaO source is controlled so as to change according to the basicity transition pattern 333 showing the transition of the basicity estimation values classified into the clusters of 4. Specifically, No. 1 shown in the graph of FIG. 6D. When the average value of the basicity estimates in the clusters of 4 is the target basicity CS _aim , and the basicity estimated value calculated by the combined reaction model after the start of charging the CaO source is CS _cal , the required CaO source input is used. The amount W _CaO is calculated by the following formula (19). In addition, <SiO ₂ > is the concentration (%) _{of SiO 2 in the slag, and WS} is the weight (ton) of the slag. When the estimated basicity value CS _cal is larger than the target basicity CS _aim , the input amount W _{CaO is set} to 0.

When controlling the input amount of the CaO source so that the estimated basicity value changes according to the time series pattern as described above, it is preferable to blow powder quicklime as the CaO source. Since powdered quicklime slags almost at the same time as it is blown in, it is possible to improve the followability of basicity to the time series pattern. As other CaO sources, massive quicklime or dolomite can be used.

Here, the No. 1 shown in FIGS. 6A and 6B above. 1 and No. Pattern 2 and No. 2 shown in FIG. 6D. The pattern 4 is about the same (1.5 to 1.7) in terms of basicity after 400 seconds, but is different from the pattern of transition of basicity. That is, when the CaO source is input only at a certain temporary point, for example, the basicity at the time when 400 seconds have passed, No. Pattern 4 and No. 1 and No. It is possible that the dephosphorization rate is low even though the pattern 2 is not distinguished and the specified basicity is realized. In this respect, in the present embodiment, it is possible to improve the dephosphorization rate more effectively by paying attention to the transition pattern of the estimated basicity value.

FIG. 8 is a flowchart schematically showing the process of the converter blowing control method according to the modified example of the first embodiment of the present invention. In the example shown in FIG. 8, unlike the example described with reference to FIG. 2 above, when the estimated basicity value in the slag falls below a predetermined threshold value, the blowing process control unit 323 uses the CaO source. It is charged in a predetermined charging amount (step S18). That is, in the case of the illustrated example, the blowing process control unit 323 does not control the input amount of the CaO source based on the basicity transition pattern 333. Even in such a case, the CaO source is charged when the estimated basicity value falls below a predetermined threshold value after the start of the blowing process, so that the basicity changes close to the pattern shown in FIG. 4 above. And the dephosphorization rate is improved.

In the first embodiment of the present invention described above, the basicity estimated value in the slag is sequentially calculated using the combined reaction model during the blowing process in the converter, and the base in the slag is calculated from the start of the blowing process. After the lapse of time that is assumed to be required for the degree to fall below the predetermined threshold, specifically, when the estimated basicity falls below the predetermined threshold, the CaO source is started to be charged. As a result, the transition of the basicity in the slag can be brought close to the pattern when the dephosphorization rate is high, and as a result, the dephosphorization rate can be improved. Furthermore, by controlling the input amount of the CaO source so that the estimated basicity value changes according to the transition pattern of the estimated basicity value when the dephosphorization rate was high in the past blowing process, the dephosphorization rate is more reliable. May be improved.

Further, in the first embodiment of the present invention, the estimated basicity in the slag is sequentially calculated, and when the calculated basicity estimated value falls below a predetermined threshold value, the CaO source is started to be charged. However, a predetermined time (predetermined time) that is assumed to be required from the start of the blowing process until the basicity in the slag falls below a predetermined threshold has elapsed without calculating the estimated basicity in the slag. Occasionally, the CaO source may be started.

(Second embodiment)
FIG. 9 is a diagram showing a schematic configuration of a refining facility including a converter blowing control device according to a second embodiment of the present invention. As shown in FIG. 9, the refining facility 1A includes a converter facility 10, a measurement control device 20, and a converter blowing control device 30A. Since the converter equipment 10 and the measurement control device 20 are the same as the examples described with reference to FIG. 1, duplicated description will be omitted.

The converter blowing control device 30A is mounted by a device including a communication unit 31, a calculation unit 32, and a storage unit 33, for example, a computer, similarly to the converter blowing control device 30 in the first embodiment. Will be done. As a difference from the above example, in the converter blowing control device 30A, the statistical model 334 is stored in the storage unit 33. Further, the calculation unit 32 functions as a delay time estimation unit 324, a CaO source input determination unit 322, and a blowing process control unit 323 by operating according to the program. Since the configuration of the converter blowing control device 30A other than the delay time estimation unit 324 and the statistical model 334 is the same as that of the converter blowing control device 30 in the example of FIG. 1, duplicated description will be omitted.

The delay time estimation unit 324 uses a statistical model 334 that uses the hot metal data 331 (for example, hot metal C, hot metal Si, hot metal P, hot metal temperature, etc.) stored in the storage unit 33 as an explanatory variable, and uses the hot metal in the blowing process. An appropriate delay time for charging the CaO source to 111 is estimated. The CaO source input determination unit 322 determines when the delay time estimated by the delay time estimation unit 324 has elapsed as the CaO source input start time. Here, the statistical model 334 is constructed based on the result of sequentially calculating the basicity estimation value in the slag 113 in the past blowing process using, for example, a statistical model building apparatus as described later. Specifically, the statistical model 334 expresses the relationship between the hot metal data in the past blowing process and the time when the estimated basicity value falls below a predetermined threshold value. Therefore, the delay time estimation unit 324 can estimate the delay time at which the basicity estimation value is below a predetermined threshold value from the hot metal data 331 in the current blowing process.

FIG. 10 is a flowchart schematically showing the process of the converter blowing control method according to the second embodiment of the present invention. In the present embodiment, as in the illustrated example, the delay time estimation unit 324 estimates the delay time from the hot metal data 331 using the statistical model 334 before the start of the blowing process in the converter 11 (step S11). Can be done (step S21). In another example, the delay time estimation may be performed after the start of the blowing process. After the start of the blowing process (step S11), the CaO source input determination unit 322 determines whether or not the estimated delay time has elapsed (step S22), and if the delay time has elapsed, the blowing process. The control unit 323 inputs the CaO source (step S23).

FIG. 11 is a diagram showing a schematic configuration of a refining facility including a statistical model building apparatus according to a second embodiment of the present invention. As shown in FIG. 11, the refining facility 1B includes a converter facility 10, a measurement control device 20, and a statistical model building device 30B. Since the converter equipment 10 and the measurement control device 20 are the same as the examples described with reference to FIG. 1, duplicated description will be omitted.

The statistical model construction device 30B is implemented by a device including a communication unit 31, a calculation unit 32, and a storage unit 33, for example, a computer, similarly to the converter blowing control device 30A in the example described with reference to FIG. Will be done. The difference from the converter blowing control device 30A is that in the statistical model building device 30B, the operation factor data 332 during the blowing process is stored in the storage unit 33. Further, the calculation unit 32 functions as a data acquisition unit 325, a basicity estimation value calculation unit 321 and a statistical model construction unit 326 by operating according to the program. Since the other configurations of the statistical model construction device 30B are the same as those of the converter blowing control device 30A in the example of FIG. 9, duplicated description will be omitted.

In the above statistical model building apparatus 30B, the data collection unit 325 collects the hot metal data 331 regarding the hot metal 111 to be blown in the converter 11 and the operation factor data 332 during the blowing process. Here, the operation factor data 332 is measured by, for example, the component concentration of the molten steel 112, the temperature of the molten steel 112, and the exhaust gas analyzer 22 acquired by the measurement using the sublance 21 of the measurement control device 20 during the blowing process. The exhaust gas component concentration, the exhaust gas flow rate measured by the exhaust gas flow rate system, the height of the top blown lance 12 controlled by the lance drive device 24, the amount of blown oxygen supplied by the blown control device 25, and the amount of blown oxygen supplied by the bottom blown gas supply device 26. It includes the flow rate of the bottom blown gas and at least a part of the charging start timing and the charging amount of the auxiliary raw material by the charging control device 27 or the blowing control device 25. The data collection unit 325 collects, for example, the hot metal data 331 and the operation factor data 332, which are measured during the past blowing process and accumulated in the storage unit 33.

The basicity estimation value calculation unit 321 sequentially calculates the basicity estimation value in the slag in the blowing process based on the hot metal data 331 and the operation factor data 332 collected by the data collection unit 325. The estimated basicity in the slag can be sequentially calculated using, for example, the combined reaction model described above. The basicity estimation value calculation unit 321 sequentially calculates the basicity estimation value in the slag for each of the past blowing processes in which the data was collected, for example. Based on the result of calculation by the basicity estimation value calculation unit 321, the statistical model construction unit 326 uses the hot metal data 331 as an explanatory variable, and the delay time from the start of the blowing process until the basicity estimation value falls below a predetermined threshold value. A statistical model 334 is constructed with the objective variable. The constructed statistical model 334 is used, for example, by the converter blowing control device 30A in the example of FIG. 9 to estimate the delay time from the new hot metal data 331.

The converter blowing control device 30A and the statistical model building device 30B described above may be the same device or different devices. When these are the same devices, the hot metal data 331, the operation factor data 332, and the statistical model 334 are stored in the storage unit 33, and the calculation unit 32 operates according to the program to determine the delay time estimation unit 324 and the CaO source input. It functions as a unit 322, a blowing process control unit 323, a data collection unit 325, a basicity estimation value calculation unit 321 and a statistical model construction unit 326. In such a device, the delay time is estimated from the new hot metal data 331 by using the statistical model 334 constructed based on the result of the sequential calculation of the basicity estimation values in the slag in the past blowing process. The statistical model 334 can be updated by sequentially calculating the basicity estimation value in the slag for the new blowing process.

FIG. 12 is a flowchart schematically showing the process of the statistical model construction method according to the second embodiment of the present invention. In the illustrated example, first, the data collection unit 325 of the statistical model building apparatus 30B collects the hot metal data 331 regarding the hot metal 111 to be blown in the converter 11 and the operation factor data 332 during the blowing process ( Step S25). Next, the basicity estimation value calculation unit 321 sequentially calculates the basicity estimation value in the slag in the blowing process based on the hot metal data 331 and the operation factor data 332 collected in step S25 (step S26). Next, the statistical model construction unit 326 constructs a statistical model 334 with the hot metal data 331 as the explanatory variable and the delay time as the objective variable based on the calculation result in step S26 (step S27). By the above processing, for example, a statistical model 334 for estimating an appropriate delay time from new hot metal data 331 can be constructed.

In the second embodiment of the present invention described above, an appropriate delay time is estimated using a statistical model using hot metal data as an explanatory variable, and CaO is elapsed after the estimated delay time elapses from the start of the blowing process. Start inputting the source. Thereby, as in the first embodiment described above, the transition of the basicity in the slag can be brought close to the pattern when the dephosphorization rate is high, and as a result, the dephosphorization rate can be improved. In the present embodiment, the delay time is estimated using a statistical model constructed based on the result of sequentially calculating the basicity estimation values in the slag in the past blowing process, before the start of the blowing process or by estimating the delay time. The time to start charging the CaO source is determined early after the start of the blowing process. Therefore, for example, there may be a delay in the execution of charging of the CaO source by the charging control device 27 or the blowing control device 25, or it may take time for the basicity to increase because the CaO source other than powdered quicklime is charged. However, the basicity in the slag can be appropriately controlled to improve the dephosphorization rate.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

1,1A, 1B ... Smelting equipment, 10 ... converter equipment, 11 ... converter, 12 ... top blow lance, 13 ... flue, 14 ... tuyere, 15 ... input device, 20 ... measurement control device, 21 ... sublance , 22 ... exhaust gas analyzer, 23 ... exhaust gas flow meter, 24 ... lance drive device, 25 ... blow control device, 26 ... bottom blow gas supply device, 27 ... input control device, 30, 30A ... converter blow control device, 30B ... Statistical model construction device, 31 ... Communication unit, 32 ... Calculation unit, 321 ... Basicity estimation value calculation unit 322 ... CaO source input determination unit 323 ... Blowing process control unit 324 ... Delay time estimation unit 325 ... Data collection unit, 326 ... Statistical model construction unit, 33 ... Storage unit, 331 ... Hot metal data, 332 ... Operation factor data, 333 ... Basicity transition pattern, 334 ... Statistical model, 34 ... Input / output unit.

Claims (14)

A CaO source charging determination unit that determines the charging start time of the CaO source charged into the hot metal blown by the converter, and a CaO source charging determination unit.
According to the determination by the CaO source injection determination unit, the blowing process for starting the injection of the CaO source after the lapse of time estimated to be required from the start of the blowing process until the basicity in the slag falls below a predetermined threshold value. A converter slag control device equipped with a control unit. Modeling the hot spot reaction, which is the oxidation reaction between the blown oxygen and the hot metal in the converter, and the slag metal interface reaction, which is the reaction in the interface region between the hot metal and the slag, excluding the region where the hot spot reaction proceeds. Further, it is provided with a basicity estimation value calculation unit that sequentially calculates the basicity estimation value in the slag using the combined reaction model.
The converter blowing according to claim 1, wherein the CaO source charging determination unit determines when the basicity estimated value falls below a predetermined threshold value after the start of the blowing process as the CaO source charging start time. Ren control device. The converter blowing control device according to claim 2, wherein the blowing process control unit controls the input amount of the CaO source so that the estimated basicity value changes according to a predetermined time series pattern. The predetermined time-series pattern is classified into the clusters in which the hot metal dephosphorization rate is the highest among the clusters obtained by clustering the transition patterns of the basicity estimates in the past blowing process. The converter blown control device according to claim 3, which shows the transition of the basicity estimated value. The converter blowing control device according to claim 3 or 4, wherein the CaO source contains powdered quicklime. The converter blowing control device according to claim 1, wherein the CaO source charging determination unit determines when a predetermined time has elapsed from the start of the blowing process as the charging start time of the CaO source. A delay time estimation unit for estimating the delay time using a statistical model using the hot metal data related to the hot metal as an explanatory variable is further provided.
The converter blowing control device according to claim 6, wherein the CaO source charging determination unit determines when the delay time has elapsed from the start of the blowing process as the charging start time of the CaO source. The converter blowing control device according to claim 7, wherein the statistical model is constructed based on the result of sequentially calculating the basicity estimation value in the slag in the past blowing process. The estimated basicity in the slag in the past blowing process is the hot spot reaction, which is the oxidation reaction between the blown oxygen and the hot metal in the converter, and the hot metal and slag excluding the region where the hot spot reaction proceeds. Sequentially calculated using a composite reaction model that models the slag metal interface reaction, which is the reaction in the interface region with and.
The converter blowing control device according to claim 8, wherein the statistical model expresses the relationship between the hot metal data and the time when the basicity estimated value falls below a predetermined threshold value. A data collection unit that collects hot metal data related to hot metal that is blown in a converter and data on operating factors during the hotning process.
A basicity estimation value calculation unit that sequentially calculates the basicity estimation value in the slag in the blowing process based on the hot metal data and the operation factor data.
Based on the result of the sequential calculation, a statistical model for constructing a statistical model in which the hot metal data is used as an explanatory variable and the delay time from the start of the blowing process until the basicity estimated value falls below a predetermined threshold value is used as the objective variable. Statistical model building device with a building unit. The process of determining the charging start time of the CaO source to be charged into the hot metal to be blown in the converter, and
According to the above determination, converter blowing control including a step of starting charging of the CaO source after the lapse of a time estimated to be required from the start of the blowing process to the time when the basicity in the slag falls below a predetermined threshold value. Method. The process of collecting the hot metal data related to the hot metal blown in the converter and the operation factor data during the hotning process, and
A step of sequentially calculating the basicity estimation value in the slag in the blowing process based on the hot metal data and the operation factor data, and
Based on the result of the sequential calculation, a step of constructing a statistical model in which the hot metal data is used as an explanatory variable and the delay time from the start of the blowing process to the time when the basicity estimated value falls below a predetermined threshold value is used as the objective variable. How to build a statistical model including. A CaO source charging determination unit that determines the charging start time of the CaO source charged into the hot metal blown by the converter, and a CaO source charging determination unit.
According to the determination by the CaO source injection determination unit, the blowing process for starting the injection of the CaO source after the lapse of time estimated to be required from the start of the blowing process until the basicity in the slag falls below a predetermined threshold value. A program for operating a computer as a converter blow control device equipped with a control unit. A data collection unit that collects hot metal data related to hot metal that is blown in a converter and data on operating factors during the hotning process.
A basicity estimation value calculation unit that sequentially calculates the basicity estimation value in the slag in the blowing process based on the hot metal data and the operation factor data.
Based on the result of the sequential calculation, a statistical model for constructing a statistical model in which the hot metal data is used as an explanatory variable and the delay time from the start of the blowing process to the time when the basicity estimated value falls below a predetermined threshold is used as the objective variable. A program for operating a computer as a statistical model building device with a building unit.

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