Molten iron temperature control method, molten iron temperature control device, molten iron temperature control system, and terminal device

Abstract

The molten iron temperature control method includes calculation steps (S11 to S19) of calculating a pulverized coal ratio manipulation amount by molten iron temperature control, calculating a pulverized coal flow rate manipulation amount by pulverized coal ratio tracking control to compensate for a deviation between a target value of the pulverized coal ratio taking into account the pulverized coal ratio manipulation amount and a current actual value of the pulverized coal ratio, and prioritizing the molten iron temperature control or the pulverized coal ratio tracking control as an optimal action based on the magnitude of discrepancy between the target value and the actual value of the pulverized coal ratio, a determination step of determining a basis for calculation of the optimal action and adding a statement to a statement of the basis indicating the basis, and a presentation step of presenting operation information including at least one of the pulverized coal ratio manipulation amount and the pulverized coal flow rate manipulation amount calculated as the optimal action and the statement of the basis.

Description

[Technical field]

[0001] The present disclosure relates to a molten metal temperature control method, a molten metal temperature control device, a molten metal temperature control system, and a terminal device. [Background technology]

[0002] The labor force is expected to decrease due to the declining birthrate and aging population, and the number of knowledgeable and experienced skilled operators is also expected to decrease in the steel industry. Therefore, there is a demand for highly efficient and stable operation through process automation.

[0003] In a blast furnace, raw materials such as coke and iron ore are charged from the top of the furnace, and hot air and pulverized coal are blown in from the tuyeres at the bottom of the furnace to melt and reduce the iron ore, and molten iron is obtained from the tap hole. In recent years, blast furnace operation has aimed for low reducing agent ratios and low coke ratios to reduce CO2 emissions and molten iron costs. On the other hand, because high-quality raw materials are becoming scarce, it is expected that fluctuations in raw material quality will become greater. Therefore, it is expected that control of the blast furnace process will become even more difficult.

[0004] Controlling the hot metal temperature (HMT) is important for achieving highly efficient and stable blast furnace operation. If the hot metal temperature drops too low, the temperature of the by-product slag drops and the viscosity of the slag increases, making it difficult to discharge from the furnace. Furthermore, if a furnace cooling accident occurs in which the hot metal or slag in the lower part of the furnace solidifies due to insufficient heat, operation may be stopped. If the target temperature is set high to avoid a drop in the hot metal temperature, a lot of fuel will be consumed, leading to an increase in the reducing agent rate. By suppressing the variation in the hot metal temperature, it becomes possible to lower the target value while still satisfying the lower limit of the hot metal temperature, leading to a reduction in the reducing agent rate.

[0005] The hot metal temperature is controlled by manipulating, for example, the coke rate, blast moisture, blast temperature, pulverized coal rate, and pulverized coal flow rate. Because the blast furnace is a process with a large heat capacity, there is a time delay of about 2 to 8 hours before the hot metal temperature changes when the operational variables are changed. Therefore, it is necessary to predict the hot metal temperature taking into account the time delay until the effect of the action appears, and to control it based on the prediction.

[0006] In light of this background, various molten iron temperature control methods have been proposed. For example, Patent Document 1 discloses a method of calculating a target value of the pulverized coal ratio by executing a dual-structure control loop of a first control (molten iron temperature control) and a second control (pulverized coal ratio tracking control). In the first control, a target value of the pulverized coal ratio is calculated so that the molten iron temperature falls within a preset target range. In the second control, a pulverized coal flow rate manipulated variable is calculated to compensate (reduce) the deviation between the target value of the pulverized coal ratio and the current actual value of the pulverized coal ratio. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 7107444 Summary of the Invention [Problem to be solved by the invention]

[0008] The method described in Patent Document 1 enables the control of the hot metal temperature that is less susceptible to the influence of unloading fluctuations. However, when the hot metal temperature deviates from the target value and there is a large discrepancy between the target value of the pulverized coal ratio and the actual value of the current pulverized coal ratio, excessive action may be performed. Here, excessive action refers to additionally performing an operation that is not essential. Although the method described in Patent Document 1 is sufficient to operate the pulverized coal flow rate (second control) to compensate for the deviation of the pulverized coal ratio, the pulverized coal ratio may be further operated (operation based on the first control). In addition, Patent Document 1 realizes automatic control, but generally, there is a tendency that the reason for the action is rarely shown in automatic control. For example, by presenting the basis for the calculation of the manipulated variable's manipulated variable, the operator can be convinced.

[0009] In consideration of the above circumstances, the objective of the present disclosure is to provide a molten metal temperature control method, a molten metal temperature control device, a molten metal temperature control system, and a terminal device that are capable of suppressing excessive actions and indicating optimal actions and the basis for calculation. [Means for solving the problem]

[0010] (1) A method for controlling molten iron temperature according to an embodiment of the present disclosure includes: a calculation step of calculating a pulverized coal ratio manipulated variable by molten iron temperature control so that a molten iron temperature predicted by a physical model capable of calculating the state inside the blast furnace falls within a preset target range, calculating a pulverized coal flow rate manipulated variable by pulverized coal ratio tracking control to compensate for a deviation between a target value of the pulverized coal ratio taking into account the pulverized coal ratio manipulated variable and a current actual value of the pulverized coal ratio, and prioritizing the molten iron temperature control or the pulverized coal ratio tracking control as an optimal action based on the magnitude of discrepancy between the target value of the pulverized coal ratio and the actual value; a determining step of determining a basis for the calculation of the optimal action and adding a statement to a basis statement indicating the basis; The method includes a presentation step of presenting operation information including at least one of the pulverized coal ratio manipulated variable and the pulverized coal flow rate manipulated variable calculated as the optimal action and the reason statement.

[0011] (2) As an embodiment of the present disclosure, in (1), In the calculation step, when the absolute value of the pulverized coal flow rate manipulation amount is larger than the manipulation range of the pulverized coal flow rate that can be changed per time, the pulverized coal ratio tracking control is prioritized, and the pulverized coal manipulation amount calculated by the molten metal temperature control is not taken into account in the target value of the pulverized coal ratio.

[0012] (3) As an embodiment of the present disclosure, in (1) or (2), In the calculation step, when the predicted molten metal temperature value calculated taking into account the pulverized coal flow rate control amount falls outside the target range of the molten metal temperature, the molten metal temperature control is prioritized and the pulverized coal control amount calculated by the molten metal temperature control is taken into account in the target value of the pulverized coal ratio.

[0013] (4) As an embodiment of the present disclosure, in any one of (1) to (3), The determining step includes adding a plurality of statements to the reason statement, The plurality of statements include a plurality of change contents arranged in order of the most recent change from the current time or the largest change amount.

[0014] (5) As an embodiment of the present disclosure, in any one of (1) to (4), the operation information is an operation amount presentation screen having a statement expressing an intention of the optimal action, a reason for calculating the optimal action, an accept button, and a reject button; the approve button is used when the operator approves the optimal action displayed on the operation amount presentation screen, The non-adopt button is used when the operator does not adopt the optimum action shown on the operation amount presentation screen.

[0015] (6) As an embodiment of the present disclosure, in (5), the presenting step includes, as a control mode, a semi-automatic mode in which the optimum action is executed with the approval of the operator, and an automatic mode in which the optimum action is executed without the approval of the operator; the operation information is an operation amount presentation screen further having a timer when the control mode is the auto mode, The timer displays the time from the time when the display regarding the optimum action is updated to a predetermined specified time, and if the non-adopted button is not selected before the specified time arrives, the optimum action is executed.

[0016] (7) A molten iron temperature control device according to an embodiment of the present disclosure includes: a calculation unit which calculates a pulverized coal ratio manipulated variable by molten iron temperature control so that a molten iron temperature predicted by a physical model capable of calculating the state inside the blast furnace falls within a preset target range, calculates a pulverized coal flow rate manipulated variable by pulverized coal ratio tracking control to compensate for a deviation between a target value of the pulverized coal ratio taking into account the pulverized coal ratio manipulated variable and a current actual value of the pulverized coal ratio, and prioritizes the molten iron temperature control or the pulverized coal ratio tracking control as an optimal action based on the magnitude of discrepancy between the target value of the pulverized coal ratio and the actual value; a determination unit that determines a basis for the calculation of the optimal action and adds a statement to a statement of basis indicating the basis; The system further includes a presentation unit that presents operation information including at least one of the pulverized coal ratio manipulated variable and the pulverized coal flow rate manipulated variable calculated as the optimal action and the reason statement.

[0017] (8) As an embodiment of the present disclosure, in (7), When the absolute value of the pulverized coal flow rate manipulation amount is greater than the manipulation range of the pulverized coal flow rate that can be changed per time, the calculation unit prioritizes the pulverized coal ratio tracking control and does not take the pulverized coal manipulation amount calculated by the molten metal temperature control into account in the target value of the pulverized coal ratio.

[0018] (9) As an embodiment of the present disclosure, in (7) or (8), When the molten metal temperature predicted value calculated taking into account the pulverized coal flow rate control amount falls outside the target range of the molten metal temperature, the calculation unit prioritizes the molten metal temperature control and takes the pulverized coal control amount calculated by the molten metal temperature control into account in the target value of the pulverized coal ratio.

[0019] (10) As an embodiment of the present disclosure, in any one of (7) to (9), The determination unit adds a plurality of statements to the reason statement, The plurality of statements include a plurality of change contents arranged in order of the most recent change from the current time or the largest change amount.

[0020] (11) As an embodiment of the present disclosure, in any one of (7) to (10), the operation information is an operation amount presentation screen having a statement expressing an intention of the optimal action, a reason for calculating the optimal action, an accept button, and a reject button; the approve button is used when the operator approves the optimal action displayed on the operation amount presentation screen, The non-adopt button is used when the operator does not adopt the optimum action shown on the operation amount presentation screen.

[0021] (12) As an embodiment of the present disclosure, in (11), the presentation unit has, as a control mode, a semi-automatic mode in which an optimum action is executed with the approval of the operator, and an automatic mode in which an optimum action is executed without the approval of the operator, the operation information is an operation amount presentation screen further having a timer when the control mode is the auto mode, The timer displays the time from the time when the display regarding the optimum action is updated to a predetermined specified time, and if the non-adopted button is not selected before the specified time arrives, the optimum action is executed.

[0022] (13) A molten iron temperature control system according to an embodiment of the present disclosure, A molten iron temperature control system comprising a molten iron temperature control device and a terminal device, a calculation unit which calculates a pulverized coal ratio manipulated variable by molten iron temperature control so that a molten iron temperature predicted by a physical model capable of calculating the state inside the blast furnace falls within a preset target range, calculates a pulverized coal flow rate manipulated variable by pulverized coal ratio tracking control to compensate for a deviation between a target value of the pulverized coal ratio taking into account the pulverized coal ratio manipulated variable and a current actual value of the pulverized coal ratio, and prioritizes the molten iron temperature control or the pulverized coal ratio tracking control as an optimal action based on the magnitude of discrepancy between the target value of the pulverized coal ratio and the actual value; a determination unit that determines a basis for the calculation of the optimal action and adds a statement to a statement of basis indicating the basis; An output unit that outputs operation information including at least one of the pulverized coal ratio manipulated variable and the pulverized coal flow rate manipulated variable calculated as the optimal action and the reason statement; A communication unit that transmits and receives the operation information; an acquisition unit that acquires the optimum action and the operation information related to the optimum action including the rationale statement; a display unit that displays the acquired optimum action and the operation information so as to include the reason statement; The device further includes an interface unit that receives an instruction for the displayed operation information and outputs a setting value for an operation variable in response to the instruction or based on the passage of a predetermined time.

[0023] (14) A terminal device according to an embodiment of the present disclosure, A terminal device constituting a molten iron temperature control system together with a molten iron temperature control device that outputs operation information including at least one of a pulverized coal ratio manipulated variable and a pulverized coal flow rate manipulated variable calculated as an optimal action based on the degree of discrepancy between a target value of the pulverized coal ratio and an actual value of the pulverized coal ratio, and a statement of reasons indicating the reasons for the calculation of the optimal action, for controlling the molten iron temperature, an acquisition unit that acquires the optimum action and the operation information related to the optimum action including the rationale statement; a display unit that displays the acquired optimum action and the operation information so as to include the reason statement; The device further includes an interface unit that receives an instruction for the displayed operation information and outputs a setting value for an operation variable in response to the instruction or based on the passage of a predetermined time.

[0024] (15) As an embodiment of the present disclosure, in (14), The operation information includes a plurality of operation conditions, and is displayed with an order of priority. Effect of the Invention

[0025] According to the present disclosure, it is possible to provide a molten metal temperature control method, a molten metal temperature control device, a molten metal temperature control system, and a terminal device that are capable of suppressing excessive actions and indicating optimal actions and the basis for calculation. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of a molten iron temperature control device according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a flowchart illustrating the process of the calculation unit. [Diagram 3] FIG. 3 is a flowchart illustrating the process of the determination unit. [Figure 4] FIG. 4 is a flowchart illustrating the process of the presentation unit. [Diagram 5] FIG. 5 is a diagram illustrating an example of the operation amount presentation screen when the control mode is the auto mode. [Figure 6] FIG. 6 is a diagram illustrating an example of an operation amount presentation screen when the control mode is the semi-automatic mode. [Figure 7] FIG. 7 is a diagram illustrating another operation amount presentation screen when the control mode is the auto mode. [Figure 8] FIG. 8 is a diagram showing an example of changes in the molten iron temperature, the target value of the pulverized coal ratio, and the set value of the pulverized coal flow rate over the past 8 hours and the future 10 hours, with the current time being set to 0. [Figure 9] FIG. 9 is a diagram showing another example of changes in the molten iron temperature, the target value of the pulverized coal ratio, and the set value of the pulverized coal flow rate for the past 8 hours and the future 10 hours, with the current time being set to 0. [Figure 10] FIG. 10 is a diagram showing an example of changes in molten metal temperature, coke rate, pulverized coal rate control amount, pulverized coal rate, pulverized coal flow rate control amount, pulverized coal flow rate, blast flow rate, and iron-making speed over 60 hours. [Figure 11] FIG. 11 is a diagram showing an example of changes in molten iron temperature, coke rate, pulverized coal rate, pulverized coal flow rate, blast flow rate, iron-making speed, and inferior raw material charging ratio over 60 hours. [Figure 12] FIG. 12 is a block diagram showing a configuration example of a molten iron temperature control system including a molten iron temperature control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, a molten iron temperature control method, a molten iron temperature control device, a molten iron temperature control system, and a terminal device according to an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals. In the description of this embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate.

[0028] [Configuration of molten iron temperature control device] Fig. 1 is a block diagram showing a configuration of a molten iron temperature control device 1 according to an embodiment of the present disclosure. As shown in Fig. 1, the molten iron temperature control device 1 according to the present embodiment can be configured by an information processing device such as a computer. Specifically, an internal arithmetic processing device such as a CPU (Central Processing Unit) executes a program, causing the computer or the like to function as the molten iron temperature control device 1.

[0029] The operation database 2 is connected to the molten iron temperature control device 1 in a data readable form. In this embodiment, the operation database 2 stores operation factors, calculated values ​​of process variables, actual values ​​of process variables, and history data of temperature or pressure measured at the furnace body, furnace top, or furnace bottom. The operation factors are, for example, the furnace top coke ratio, blast flow rate, enriched oxygen amount, blast temperature, blast moisture, pulverized coal ratio, pulverized coal flow rate, etc. The calculated values ​​of the process variables are the gas utilization rate, solution loss carbon, molten iron temperature, and iron-making speed outputted by the physical model. The actual values ​​of the process variables are calculated based on, for example, the volume fraction of CO or CO2 in the discharged furnace top gas. The process variables include the iron-making speed, molten iron temperature, solution loss carbon, and gas utilization rate. The operation database 2 sequentially saves and stores measurement data required for operation and operation factors required for molten iron temperature control, and this information is read out and used as necessary. In addition, the calculated values ​​of the process variables output by the physical model are sequentially stored in the operation database 2 each time the molten iron temperature control device 1 performs a calculation.

[0030] The physical model used in this disclosure is the same as the method described in the reference (Michiharu Hatano et al.: "Study on blow-in operation using a blast furnace non-steady-state model", Tetsu-to-Haganen, vol. 68, p. 2369). That is, the physical model is composed of a group of partial differential equations that consider multiple physical phenomena such as reduction of iron ore, heat exchange between iron ore and coke, and melting of iron ore, and is a physical model that can calculate variables (output variables) that indicate the state inside the blast furnace in a non-steady state.

[0031] The molten iron temperature control device 1 according to this embodiment includes a calculation unit 11, a determination unit 12, and a presentation unit 13. The molten iron temperature control device 1 can control the molten iron temperature by the calculation unit 11, the determination unit 12, and the presentation unit 13 executing the processes described below. The molten iron temperature control device 1 may also include a storage device, in which case the storage device may store a physical model. When executing the processes described below, the molten iron temperature control device 1 may read out the physical model from the storage device and use it for calculation.

[0032] [Calculation section operation] The operation of the calculation unit 11 will be described with reference to Fig. 2. At least a part of the process shown in Fig. 2 corresponds to a calculation step executed by the calculation unit 11.

[0033] Fig. 2 is a flowchart showing the flow of processing in the calculation unit 11. The flowchart shown in Fig. 2 starts when an execution command is input to the calculation unit 11, and proceeds to processing in step S11.

[0034] In the process of step S11, the calculation unit 11 calculates the pulverized coal ratio manipulated variable ΔPCR0 so that the molten iron temperature predicted by the physical model falls within a preset target range. In this embodiment, the calculation method of step S11 is the same as the molten iron temperature control method described in the above Patent Document 1. That is, ΔPCR0 and the following ΔPCI0 are calculated by the molten iron temperature control.

[0035] In calculating the pulverized coal ratio manipulated variable (ΔPCR), which is the manipulated variable of the pulverized coal ratio (PCR), a so-called speed-type method is used, in which the change is increased or decreased from the manipulated variable. Therefore, the pulverized coal ratio after adjustment is calculated based on the current pulverized coal ratio target value (PCR ref It is set by adding ΔPCR to the PCR signal (0).

[0036] Next, using the current ironmaking rate Prod(0) and relaxation coefficient α0 (0<α0≦1), the pulverized coal flow rate manipulated variable ΔPCI0 corresponding to the pulverized coal ratio manipulated variable ΔPCR0 is calculated by equation (1). The pulverized coal flow rate manipulated variable (ΔPCI) is the manipulated variable of the pulverized coal flow rate (PCI). The subscript 0 indicates that it corresponds to ΔPCR0. For the pulverized coal flow rate as well, the pulverized coal flow rate manipulated variable ΔPCI0 is calculated as an increase or decrease from the current PCI value. The processing of the calculation unit 11 proceeds to processing of step S12.

[0037]

number

[0038] In the process of step S12, the calculation unit 11 calculates the pulverized coal flow rate manipulated variable to compensate for the deviation between the target value of the pulverized coal ratio and the current value (current actual value of the pulverized coal ratio). In this embodiment, the calculation method in step S12 is the same as the method of pulverized coal ratio tracking control described in the above Patent Document 1. That is, the following ΔPCR1 is calculated by the pulverized coal ratio tracking control. First, the current pulverized coal flow rate is PCI(0), the target value of the pulverized coal ratio is PCR(1), and the pulverized coal ratio is PCI(2). ref (0), the deviation δPCR between the target value and the actual value of the pulverized coal ratio is calculated by equation (2).

[0039]

number

[0040] Next, the pulverized coal flow rate manipulated variable ΔPCI1 for compensating for the deviation ΔPCR between the target value and the actual value of the pulverized coal ratio is calculated by the equation (3) using the relaxation coefficient α1 (0<α1≦1). The process of the calculation unit 11 proceeds to the process of step S13.

[0041]

number

[0042] In the process of step S13, the calculation unit 11 judges whether the absolute value |ΔPCI1| of the pulverized coal flow rate manipulated variable for compensating for the deviation ΔPCR between the target value and the actual value of the pulverized coal ratio is larger than the operation width A of the pulverized coal flow rate that can be changed at one time. |ΔPCI1| being larger than the operation width A means that the discrepancy between the actual value of the pulverized coal ratio and the current target value of the pulverized coal ratio is large. Here, in the method described in the above Patent Document 1, when the molten pig iron temperature is out of the target value and the discrepancy between the target value of the pulverized coal ratio and the current actual value of the pulverized coal ratio is large, there is a risk that an excessive action will be performed. In this embodiment, when this discrepancy is large, the increase or decrease in the pulverized coal ratio manipulated variable based on the molten pig iron temperature control is not taken into consideration in principle, that is, the pulverized coal ratio is not added to the target value, and only the operation of the pulverized coal flow rate for the purpose of following the pulverized coal ratio target value at that time is set as the optimal action. When this dissociation is large, the pulverized coal manipulated variable calculated by the molten iron temperature control is not taken into account (is not reflected) in the target value of the pulverized coal ratio, thereby suppressing excessive action. That is, in this embodiment, when the dissociation is large, the pulverized coal ratio tracking control is prioritized as a rule, and only the pulverized coal flow rate is manipulated to compensate for the deviation of the pulverized coal ratio, thereby preventing a decrease in accuracy of the molten iron temperature control due to excessive manipulation of the pulverized coal ratio. When |ΔPCI1| is larger than the operation width A (Yes in step S13), the calculation unit 11 proceeds to the process of step S14. Also, when |ΔPCI1| is equal to or smaller than the operation width A (No in step S13), the calculation unit 11 proceeds to the process of step S19.

[0043] In the process of step S14, the calculation unit 11 calculates a predicted value of the molten iron temperature taking into account the pulverized coal flow rate operation amount ΔPCI1. PCI (k|t0) and the free response of the hot metal temperature y assuming that the current input variables are maintained in the future free (t0+k) is calculated using a physical model. The predicted molten iron temperature y pre(t0+k) is calculated by the formula (4). The calculation unit 11 proceeds to the process of step S15.

[0044]

number

[0045] In the process of step S15, the calculation unit 11 calculates the molten iron temperature prediction value y pre It is judged whether (t0+k) is within the target range of the molten iron temperature. When the process of step S15 is performed, the target value of the pulverized coal ratio and the actual value are largely different from each other. If the pulverized coal ratio tracking control is prioritized, the molten iron temperature may remain lower or higher than the target (i.e., it may fall outside the target range of the molten iron temperature). In this case, the pulverized coal ratio may be manipulated by prioritizing the molten iron temperature control. The predicted molten iron temperature value y pre If (t0+k) is within the target range of the molten iron temperature (Yes in step S15), the calculation unit 11 proceeds to the process of step S16. pre When (t0+k) is not within the target range of the molten iron temperature (No in step S15), the calculation unit 11 proceeds to the process of step S18. The calculation unit 11 prioritizes the molten iron temperature control or the pulverized coal ratio tracking control as the optimal action based on the magnitude of discrepancy between the target value and the actual value of the pulverized coal ratio.

[0046] In the process of step S16, the calculation unit 11 sets the "pulverized coal ratio tracking control priority flag." The calculation unit 11 proceeds to the process of step S17.

[0047] In the process of step S17, the calculation unit 11 does not take ΔPCI0 into account in the pulverized coal ratio manipulated variable ΔPCR to be finally presented, sets the pulverized coal flow rate manipulated variable ΔPCI to be finally presented as ΔPCI1, and ends the series of processes.

[0048] In the process of step S18, the calculation unit 11 sets the “molten iron temperature control priority flag.” The calculation unit 11 proceeds to the process of step S19.

[0049] In the processing of step S19, the calculation unit 11 sets the pulverized coal ratio manipulation variable ΔPCR to be finally presented to ΔPCR0, and sets the pulverized coal flow rate manipulation variable ΔPCI to be finally presented to the sum of ΔPCI0 and ΔPCI1 (the value obtained by adding ΔPCI1 to ΔPCI0), and then terminates the series of processing.

[0050] [Operation of the judgment unit] The operation of the determination unit 12 will be described with reference to Fig. 3. At least a part of the process shown in Fig. 3 corresponds to a determination step executed by the determination unit 12. The determination unit 12 determines the basis for the calculation of the optimal action, and adds a statement to the statement of basis indicating the basis. Specific examples of the statement to be added will be described later.

[0051] Fig. 3 is a flowchart showing the flow of processing in the determination unit 12. The flowchart shown in Fig. 3 starts when an execution command is input to the determination unit 12, and proceeds to the determination in step S21.

[0052] In the process of step S21, the judgment unit 12 judges whether or not the pulverized coal ratio tracking control priority flag is set in the calculation unit 11. If the pulverized coal ratio tracking control priority flag is set, the judgment unit 12 proceeds to the process of step S22. If the pulverized coal ratio tracking control priority flag is not set, the judgment unit 12 proceeds to the process of step S23.

[0053] In the process of step S22, the judgment unit 12 adds "Priority given to pulverized coal ratio tracking control" to the reason statement. The reason statement indicates the reason for an operation (action) in the operation, and is the content displayed in "Basis 32 for presenting optimal action" described later. The reason statement may be stored in a storage device provided in the molten iron temperature control device 1. As a result, the judgment unit 12 proceeds to the process of step S25.

[0054] In the process of step S23, the determination unit 12 judges whether or not the molten iron temperature control priority flag is set in the calculation unit 11. If the molten iron temperature control priority flag is set, the determination unit 12 proceeds to the process of step S24. If the molten iron temperature control priority flag is not set, the determination unit 12 proceeds to the process of step S25.

[0055] In the process of step S24, the determination unit 12 adds "molten iron temperature control takes priority" to the reason statement, whereby the determination unit 12 proceeds to the process of step S25.

[0056] In the process of step S25, the determination unit 12 determines whether or not the action for the pulverized coal ratio or the pulverized coal flow rate conflicts with an operational constraint that requires the postponement of the action.

[0057] For example, if the pulverized coal ratio is excessive, this may lead to poor permeability. Therefore, there may be an operational constraint in the form of an upper limit of the pulverized coal ratio. When the current target value of the pulverized coal ratio exceeds the upper limit, the determination unit 12 adds "upper limit of the pulverized coal ratio" to the reasoning statement. Also, for example, when the reducing agent ratio is extremely small, this may lead to a sudden drop in the molten iron temperature and poor permeability. Therefore, there may be an operational constraint in the form of a lower limit of the reducing agent ratio. When the current reducing agent ratio is below the lower limit, the determination unit 12 adds "lower limit of the reducing agent ratio" to the reasoning statement. Also, for example, when the top gas temperature is low, soot may be generated at the top of the furnace or moisture in the blast furnace gas may condense, which may damage the blast furnace equipment. Therefore, there may be an operational constraint in the form of a lower limit of the top gas temperature. When the current top gas temperature is below the lower limit, the determination unit 12 adds "lower limit of the top gas temperature" to the reasoning statement. Furthermore, for example, if the theoretical combustion temperature at the tip of the tuyere is too low, the pulverized coal may not burn in the tuyere. On the other hand, if the theoretical combustion temperature is too high, the tuyere may be damaged. Therefore, there may be operational constraints in the form of upper and lower limits of the theoretical combustion temperature. If the current theoretical combustion temperature is not within the range of the upper and lower limits, the judgment unit 12 adds "upper theoretical combustion temperature limit" or "lower theoretical combustion temperature limit" to the reason statement.

[0058] If the operation constraints as described above are violated, the determination unit 12 proceeds to the process of step S26. If the operation constraints are not violated, the determination unit 12 proceeds to the process of step S27.

[0059] In the process of step S26, the determination unit 12 adds, for example, "upper limit of pulverized coal ratio," "lower limit of reducing agent ratio," "lower limit of top gas temperature," "upper limit of theoretical combustion temperature," or "lower limit of theoretical combustion temperature" to the grounds statement as described above. Then, the determination unit 12 proceeds to the process of step S27.

[0060] In the process of step S27, the judgment unit 12 judges whether or not there has been a change in the operation variable or the index from the transition of the operation variable related to the molten iron temperature control and the index highly correlated with the molten iron temperature. Examples of the operation variables include the coke ratio, the pulverized coal ratio, the blast temperature, and the blast humidity. Examples of the index highly correlated with the molten iron temperature include the tuyere embedding temperature, the silicon and sulfur components in the molten iron, the theoretical combustion temperature, and the solution loss carbon. The judgment unit 12 can judge whether or not there has been a change by calculating the difference from the current value and the absolute value of the difference exceeding a threshold. The judgment unit 12 may also judge the change in the index using a machine learning model that inputs a graph of the transition. When multiple items have changed, the judgment unit 12 may arrange the corresponding multiple phrases in order of proximity to the current time or in order of the amount of change. When there has been a change in the operation variable or the index, the judgment unit 12 proceeds to the process of step S28. When there has been no change in the operation variable and the index, the judgment unit 12 ends the series of processes.

[0061] In the process of step S28, the determination unit 12 adds, for example, the manipulated variable or index that has changed, the time when the change occurred (for example, how many hours before the current time), and the direction of the change (for example, increased or decreased) to the basis statement in association with each other. With this, the determination unit 12 ends a series of processes. In this way, the determination unit 12 adds a statement to the basis statement indicating the basis for the calculation of the above-mentioned optimal action.

[0062] As described above, the rationale statement may include a plurality of operational constraints and changes. However, in order to avoid excessive information, it is preferable that the number of operational constraints and changes included in the rationale statement is 1 to 4.

[0063] [Display operation] The operation of the presentation unit 13 will be described with reference to Fig. 4. The presentation unit 13 presents operation information to the operator. At least a part of the process shown in Fig. 4 corresponds to a presentation step executed by the presentation unit 13.

[0064] Fig. 4 is a flowchart showing the flow of processing in the presentation unit 13. The flowchart shown in Fig. 4 starts when an execution command is input to the presentation unit 13, and proceeds to processing in step S31.

[0065] In the process of step S31, the presentation unit 13 judges whether the absolute value of the operation amount of the optimal action obtained by the calculation unit 11 exceeds the minimum unit that can be changed, thereby judging whether or not the action is necessary. For example, when the target value of the pulverized coal ratio is changed in units of at least 2 kg / t, even if the calculation unit 11 calculates the pulverized coal ratio operation amount to +1 kg / t, it is judged that the action is not necessary. The process of step S31 can suppress the presentation of excessive frequency. In addition, suppressing the presentation of excessive frequency leads to the prevention of hunting of the molten iron temperature. If it is judged that the action is necessary in step S31, the process of the presentation unit 13 proceeds to the process of step S32. If it is judged that the action is not necessary in step S31, the process of the presentation unit 13 ends the series of processes.

[0066] In the process of step S32, the presentation unit 13 determines whether τ1 minutes have passed since the last action was performed. τ1 is non-zero, but is not limited to a specific value. If τ1 minutes have passed since the last action was performed, the process of the presentation unit 13 proceeds to the process of step S33. If τ1 minutes have not passed since the last action was performed, the process of the presentation unit 13 ends the series of processes. Since the blast furnace is a process with a long time constant, it takes time for the effect of the action to be manifested. Therefore, performing a similar action shortly after the most recent operation may result in an excessive action. The process of step S32 is important to prevent excessive action. Here, τ1 is preferably selected including a plurality of values. It is preferable that τ1 is set to a different value when an emergency operation is required, such as when the blast flow rate, the amount of enriched oxygen, or the coke ratio has recently been significantly changed, and when it is normal.

[0067] In the process of step S33, the presentation unit 13 judges whether the difference between the set value of the operation variable (e.g., blast flow rate, oxygen enrichment amount, or coke ratio) used in the process of step S32 and the set value of the operation variable currently set is within a threshold value. If it is within the threshold value, the process of the presentation unit 13 proceeds to the process of step S34. If it is greater than the threshold value, the process of the presentation unit 13 ends the series of processes. If the operator significantly changes the set value during the series of processes due to some reason such as equipment trouble or furnace malfunction, the operation amount obtained by the process of the calculation unit 11 is not a recommended action, and executing it may deteriorate the controllability of the molten iron temperature. The process of step S33 makes it possible to prevent the molten iron temperature control device 1 from running out of control due to disturbances.

[0068] In the process of step S34, the presenter 13 determines the control mode that has been set. In this embodiment, the presenter 13 has two control modes. That is, the presenter 13 can use a semi-automatic mode in which the optimum action is executed with the approval of the operator, or an automatic mode in which the optimum action is executed without the approval of the operator. If the control mode is the automatic mode, the process of the presenter 13 proceeds to the process of step S35. If the control mode is the semi-automatic mode, the process of the presenter 13 proceeds to the process of step S36.

[0069] In the process of step S35, information based on the optimum action shown in FIG. 5 is displayed as a pop-up on the operation terminal of the operator, and an alarm is issued. When the control mode is the auto mode, a timer 36 is provided on the screen until the action is executed. At the moment when the pop-up is displayed, that is, when the display regarding the optimum action is updated, τ2 seconds is set in the timer 36, and a countdown starts. If the operator presses the non-adopted button 35 before the timer 36 reaches 0 seconds, the pop-up is erased, and the process of the presentation unit 13 ends a series of processes. If the operator does not press (does not select) the non-adopted button 35 or presses (selects) the accept button 34 before the timer 36 reaches 0 seconds, the process of the presentation unit 13 proceeds to the process of step S37. That is, if the operator does not reject within τ2 seconds, the optimum action is executed. An alarm may be issued at the timing of τ3 that satisfies 0≦τ3≦τ2 so that the operator can be aware of the automatic execution of the action. τ2 and τ3 are non-zero, but are not limited to specific numerical values. Here, "0 seconds" is an example of a predetermined time, and another value may be used. The timer 36 is not limited to a down timer, and may be any timer that displays the time remaining until the predetermined time.

[0070] In the process of step S36, information based on the optimal action shown in FIG. 6 is displayed as a pop-up on the operation terminal of the operator, and an alarm is issued. When the control mode is the semi-automatic mode, the timer 36 until the action is executed is not provided on the screen. The execution of the action requires the approval of the operator. When the operator presses the approval button 44, the process of the presentation unit 13 proceeds to the process of step S37. When the operator presses the reject button 45, the pop-up is erased, and the process of the presentation unit 13 ends the series of processes. To prevent the operator from leaving the pop-up displayed, an alarm may be issued every time τ4 minutes have elapsed without pressing either the approval button 44 or the reject button 45 from the moment the pop-up is displayed. τ4 is non-zero, but is not limited to a specific value.

[0071] In the process of step S37, the pop-up displayed in step S35 or step S36 disappears, and the set value of the manipulated variable is overwritten (updated) by the value calculated according to the optimal action. This completes the process of step S37, and the presentation unit 13 ends the series of processes. The overwritten (updated) set value of the manipulated variable is output to, for example, a computer that controls the operating equipment 4 (see FIG. 12), and is reflected in the operating equipment 4.

[0072] [Operation amount presentation screen] FIG. 5 is a diagram showing an operation amount presentation screen when the control mode of the molten iron temperature control device 1 is the auto mode.

[0073] The manipulated variable presentation screen displays a statement 31 expressing the intention of the optimal action (e.g., increasing the molten iron temperature, decreasing the molten iron temperature, or controlling the pulverized coal ratio, etc.) and a presentation reason 32 for the optimal action determined by the determination unit 12. The manipulated variable presentation screen also displays an optimal manipulated variable 33, an approval button 34, a reject button 35, and a timer 36. The optimal manipulated variable 33 displays at least one of the pulverized coal ratio manipulated variable and the pulverized coal flow rate manipulated variable calculated as the optimal action.

[0074] FIG. 6 is a diagram showing an operation amount presentation screen when the control mode of the molten iron temperature control device 1 is the semi-automatic mode.

[0075] The manipulated variable presentation screen displays a statement 41 indicating the direction of the optimal action (e.g., increasing the molten iron temperature, decreasing the molten iron temperature, or controlling the pulverized coal ratio, etc.) and a presentation reason 42 for the optimal action determined by the determination unit 12. The manipulated variable presentation screen also displays an optimal manipulated variable 43, an accept button 44, and a reject button 45. The optimal manipulated variable 43 displays at least one of the pulverized coal ratio manipulated variable and the pulverized coal flow rate manipulated variable calculated as the optimal action.

[0076] FIG. 7 is a diagram showing another operation amount presentation screen when the control mode of the hot metal temperature control device 1 is the auto mode. In FIG. 7, the pulverized coal ratio operation amount and the pulverized coal flow rate operation amount calculated as the optimal action are presented, and two cases are presented in which another operation amount (blast moisture in the example of FIG. 7) calculated by the hot metal temperature control based on the physical model is used as another action. In the example of FIG. 7, the operation information includes a plurality of operation conditions and is displayed together with the priority order (1 to 3 in FIG. 7). Here, there is a possibility that there is an operation amount that cannot be operated due to operational constraints. Therefore, as in the example of FIG. 7, it is preferable to present a plurality of recommended actions and have the operator select an operation. In addition, in order to prevent button pressing errors, a specification may be adopted in which the "execute" button is pressed after the "accept" or "reject" button is pressed.

[0077] [Example 1] In this embodiment, a case where the molten iron temperature control priority flag is established by the processing of the calculation unit 11 is shown in FIG. 8. FIG. 8 is a diagram showing changes in the molten iron temperature (HMT), the target value of the pulverized coal ratio (PCR), and the set value of the pulverized coal flow rate (PCI) for the past 8 hours and the future 10 hours, with the current time set to 0. The dashed lines for the molten iron temperature are the upper and lower limits of the target value. The thick solid lines for the past 8 hours are the actual values. The thin solid lines are the calculated values ​​of a physical model including future predictions. The dotted lines are the predicted values ​​of the molten iron temperature when the calculated action is performed. The triangular plot of the pulverized coal ratio represents the actual value of the pulverized coal ratio at the current time. The arrows for the pulverized coal ratio and the pulverized coal flow rate indicate the action calculated in the calculation unit 11. In this embodiment, while there is a large discrepancy between the target value and the actual value of the pulverized coal ratio, if pulverized coal ratio tracking control is prioritized, the rise in the molten iron temperature cannot be suppressed. Therefore, the action of pulverized coal ratio and pulverized coal flow rate was proposed, with priority given to molten iron temperature control.

[0078] [Example 2] In this embodiment, a case where the pulverized coal ratio tracking control priority flag is set by the processing of the calculation unit 11 is shown in Fig. 9. Fig. 9 is a diagram showing changes in the molten pig iron temperature, the target value of the pulverized coal ratio, and the set value of the pulverized coal flow rate for the past 8 hours and the future 10 hours, with the current time set to 0, at a time different from that in Fig. 8. In this embodiment, while there is a large discrepancy between the target value and the actual value of the pulverized coal ratio, the molten pig iron temperature was predicted not to change significantly. Therefore, the pulverized coal ratio tracking control was prioritized, and only the action for the pulverized coal flow rate was presented.

[0079] [Example 3] In this embodiment, the operation was carried out by manipulating the pulverized coal ratio and the pulverized coal flow rate using the semi-automatic mode as the control mode in the molten iron temperature control device 1. τ1 was 40 [min].

[0080] FIG. 10 shows the changes in molten iron temperature, coke rate, pulverized coal rate control amount, pulverized coal rate, pulverized coal flow rate control amount, pulverized coal flow rate, blast flow rate, and iron-making speed over 60 hours.

[0081] In the molten iron temperature and pulverized coal ratio in FIG. 10, the solid lines are actual values. The dashed lines indicate target values. The circles in FIG. 10 for the pulverized coal ratio operation amount and the pulverized coal flow rate operation amount are actual values. The triangles are optimal actions calculated by the molten iron temperature control device 1. The operator accepted all of the optimal actions presented by the molten iron temperature control device 1. Therefore, for the pulverized coal ratio operation amount and the pulverized coal flow rate operation amount in FIG. 10, the optimal actions and the actual operations (performance) all match. As shown in FIG. 10 for the pulverized coal ratio and pulverized coal flow rate, the actual value of the pulverized coal ratio followed the target value by appropriately adjusting the pulverized coal flow rate. In addition, the coke ratio in FIG. 10 gradually decreased due to manual operation by the operator, but as shown in FIG. 10 for the pulverized coal ratio, the effect of the decrease in the coke ratio on the molten iron temperature was offset by the molten iron temperature control device 1 increasing the target value of the pulverized coal ratio. In other words, the molten iron temperature was controlled close to the target value.

[0082] [Example 4] In this example, the operation was carried out by manipulating the pulverized coal ratio and the pulverized coal flow rate using the auto mode as the control mode in the molten iron temperature control device 1 for a period different from that of Example 3. τ1 was 40 [min].

[0083] FIG. 11 shows the changes in molten iron temperature, coke rate, pulverized coal rate, pulverized coal flow rate, blast flow rate, iron-making speed, and inferior raw material charging ratio over an 11-day period.

[0084] The molten iron temperature in FIG. 11 shows the difference from the target molten iron temperature value at time zero. The graphs other than the molten iron temperature in FIG. 11 have the period average value set to zero. As a result of automatically controlling the pulverized coal ratio and pulverized coal flow rate by the molten iron temperature control device 1 in all periods in the figure, the molten iron temperature fluctuated within the range of -25 to 35°C, and automatic control of the molten iron temperature was possible. In addition, the blast flow rate was reduced due to deterioration of permeability on the 9th day, so the molten iron temperature decreased, but the molten iron temperature was controlled to be close to the target value by increasing the pulverized coal ratio. Furthermore, although yard sintering and yard coke were used in all periods in the figure, the fluctuation of the molten iron temperature was suppressed. In this way, it was confirmed that the control performance of the molten iron temperature control device 1 was good even under severe operating conditions such as when the blast rate was reduced due to deterioration of permeability or when inferior raw materials were used.

[0085] (molten iron temperature control system) FIG. 12 is a block diagram showing a configuration example of a molten iron temperature control system including a molten iron temperature control device 1. The molten iron temperature control system is configured to include a molten iron temperature control device 1 and a terminal device 3. The molten iron temperature control system may further include an operation database 2. In the molten iron temperature control system, the molten iron temperature control device 1 may include a communication unit 14 that transmits and receives operation information in addition to the calculation unit 11, the determination unit 12, and the presentation unit 13. The communication unit 14 transmits the optimal action, operation information, etc., particularly to the terminal device 3. In the molten iron temperature control system, the molten iron temperature control device 1 can present the optimal action, operation information, etc., via the terminal device 3 instead of directly presenting the information. Therefore, the presentation unit 13 functions as an output unit that outputs the optimal action, operation information, etc., to the communication unit 14. The terminal device 3 is, for example, a device used by an operator. The terminal device 3 may be a mobile terminal such as a smartphone or a tablet. The operation equipment 4 is equipment used in blast furnace operation. The molten iron temperature control system is configured to be able to communicate with the operating equipment 4 via a network, and outputs, for example, set values ​​of the operational variables updated in accordance with the optimal action to the operating equipment 4. In the molten iron temperature control system, the molten iron temperature control device 1 executes the above-mentioned processing, and screens such as those in Figs. 5 to 7 are displayed on the terminal device 3, and, for example, an operator operates (gives instructions), and the set values ​​of the operational variables are output to the operating equipment 4 in accordance with the instructions. The molten iron temperature control device 1 is also capable of receiving instructions regarding the operation information from the operator via the communication unit 14.

[0086] (Terminal Device) The terminal device 3 includes an acquisition unit 131, a display unit 132, and an interface unit 133. The acquisition unit 131 acquires an optimum action and operation information related to the optimum action, including a statement of reasons. The display unit 132 displays the acquired optimum action and operation information, including the statement of reasons. For example, the display unit 132 may display operation information (see FIG. 7 ), including the statement of reasons and a plurality of operation conditions, in which the operation conditions are displayed together with their priority order. The interface unit 133 accepts an instruction for the displayed operation information, and outputs the set value of the operation variable in response to the instruction or based on the passage of a predetermined time. Here, the set value of the operation variable may be output to the operation equipment 4 directly by the interface unit 133, or via the molten iron temperature control device 1.

[0087] The molten iron temperature control device 1, the operation database 2, the terminal device 3, and the operation equipment 4 are configured to be able to communicate with each other via a network such as a LAN (Local Area Network) or the Internet. Here, the configuration in FIG. 12 is an example. The molten iron temperature control device 1 and the terminal device 3 do not need to include all of the components shown in FIG. 12. The molten iron temperature control device 1 and the terminal device 3 may include components other than those shown in FIG. 12. The components included in the molten iron temperature control device 1 and the terminal device 3 are not limited to the example in FIG. 12. For example, the determination unit 12 and the display unit 132 may be included in the same device. For example, some of the components included in the molten iron temperature control device 1 in FIG. 12 may be included in the terminal device 3. For example, some of the components included in the terminal device 3 in FIG. 12 may be included in the molten iron temperature control device 1. Therefore, a molten iron temperature control system comprising a molten iron temperature control device 1 and a terminal device 3 may be configured as a whole to comprise a calculation unit 11, a judgment unit 12, a presentation unit 13 (output unit), a communication unit 14, an acquisition unit 131, a display unit 132, and an interface unit 133.

[0088] As described above, the molten iron temperature control method, molten iron temperature control device 1, molten iron temperature control system, and terminal device 3 according to this embodiment can suppress excessive actions and show optimal actions and the basis for calculations by the above-mentioned steps and configurations. In this embodiment, even in automatic control (auto mode), the basis for calculations is presented to the operator, so that the operator can be convinced. In addition, the operation amount presentation screen having an accept button and a reject button is suitable for the operator to quickly indicate acceptance or rejection, and is preferable as an interface for blast furnace operation, for example, where a decision may be required every few minutes.

[0089] Although the embodiment has been described above, the present disclosure is not limited by the description and drawings that form a part of the present disclosure according to the present embodiment. For example, a change in the operation variable for controlling the molten iron temperature leads to a fluctuation in the tuyere gas temperature. From the viewpoint of equipment maintenance such as tuyere refractory and prevention of deterioration of permeability due to unburned pulverized coal, it is preferable to keep the tuyere gas temperature within a predetermined range. Therefore, it is possible to visualize how the tuyere gas temperature changes when the optimal action calculated by the molten iron temperature control device 1 is implemented on the operation amount presentation screen. In other words, other embodiments, examples, operation techniques, etc. made by those skilled in the art based on the present embodiment are all included in the scope of the technology disclosed herein. [Explanation of symbols]

[0090] 1. Molten iron temperature control device 2 Operation Database 3 Terminal Equipment 4. Operational Facilities 11 Calculation section 12 Judgment section 13 Presentation unit (output unit) 14 Communications Department 31 Statement expressing the intention of the optimal action 32 Basis for suggesting optimal action 33 Optimal Operation Amount 34 Agree button 35 Not Accepted Button 36 Timer 41 Statement expressing the intention of the optimal action 42 Basis for suggesting optimal action 43 Optimal Operation 44 Agree button 45 Reject button 131 Acquisition Department 132 Display section 133 Interface section

Claims

1. a calculation step of calculating a pulverized coal ratio manipulated variable by molten iron temperature control so that a molten iron temperature predicted by a physical model capable of calculating the state inside the blast furnace falls within a preset target range, calculating a pulverized coal flow rate manipulated variable by pulverized coal ratio tracking control to compensate for a deviation between a target value of the pulverized coal ratio taking into account the pulverized coal ratio manipulated variable and a current actual value of the pulverized coal ratio, and prioritizing the molten iron temperature control or the pulverized coal ratio tracking control as an optimal action based on the magnitude of discrepancy between the target value of the pulverized coal ratio and the actual value; a determining step of determining a basis for the calculation of the optimal action and adding a statement to a basis statement indicating the basis; a presentation step of presenting operation information including at least one of the pulverized coal ratio manipulated variable and the pulverized coal flow rate manipulated variable calculated as the optimal action and the reason statement.

2. 2. The molten iron temperature control method according to claim 1, wherein, in the calculation step, when an absolute value of the pulverized coal flow rate manipulation amount is larger than an operation range of the pulverized coal flow rate that can be changed at one time, the pulverized coal ratio tracking control is prioritized, and the pulverized coal manipulation amount calculated by the molten iron temperature control is not taken into account in the target value of the pulverized coal ratio.

3. 3. The molten iron temperature control method according to claim 1 or 2, wherein, when a molten iron temperature predicted value calculated taking into account the pulverized coal flow rate operation amount falls outside a target range of the molten iron temperature, the calculation step prioritizes the molten iron temperature control and takes into account the pulverized coal operation amount calculated by the molten iron temperature control in the target value of the pulverized coal ratio.

4. The determining step includes adding a plurality of statements to the reason statement, The molten iron temperature control method according to claim 1 or 2, wherein the plurality of statements include a plurality of change contents arranged in order of the most recent change from the current time or the largest change amount.

5. the operation information is an operation amount presentation screen having a statement expressing an intention of the optimal action, a reason for calculating the optimal action, an accept button, and a reject button; the approve button is used when the operator approves the optimal action displayed on the operation amount presentation screen, The molten iron temperature control method according to claim 1 or 2, wherein the non-adoption button is used when the operator does not adopt the optimal action shown on the operation amount presentation screen.

6. the presenting step includes, as a control mode, a semi-automatic mode in which the optimum action is executed with the approval of the operator, and an automatic mode in which the optimum action is executed without the approval of the operator; the operation information is an operation amount presentation screen further having a timer when the control mode is the auto mode, 6. The molten iron temperature control method according to claim 5, wherein the timer displays a time from a point in time when the display regarding the optimal action is updated to a predetermined specified time, and if the non-adopted button is not selected before the predetermined time arrives, the optimal action is executed.

7. a calculation unit which calculates a pulverized coal ratio manipulated variable by molten iron temperature control so that a molten iron temperature predicted by a physical model capable of calculating a state inside a blast furnace falls within a preset target range, calculates a pulverized coal flow rate manipulated variable by pulverized coal ratio tracking control to compensate for a deviation between a target value of the pulverized coal ratio taking into account the pulverized coal ratio manipulated variable and a current actual value of the pulverized coal ratio, and prioritizes the molten iron temperature control or the pulverized coal ratio tracking control as an optimal action based on the magnitude of discrepancy between the target value of the pulverized coal ratio and the actual value; a determination unit that determines a basis for the calculation of the optimal action and adds a statement to a statement of basis indicating the basis; a presentation unit that presents operation information including at least one of the pulverized coal ratio manipulated variable and the pulverized coal flow rate manipulated variable calculated as the optimal action and the reason statement.

8. The molten iron temperature control device according to claim 7, wherein when an absolute value of the pulverized coal flow rate manipulation amount is larger than an operation range of the pulverized coal flow rate that can be changed at one time, the calculation unit prioritizes the pulverized coal ratio tracking control and does not take into account the pulverized coal manipulation amount calculated by the molten iron temperature control in the target value of the pulverized coal ratio.

9. 9. The molten iron temperature control device according to claim 7 or 8, wherein when a molten iron temperature predicted value calculated taking into account the pulverized coal flow rate control amount falls outside a target range of the molten iron temperature, the calculation unit prioritizes the molten iron temperature control and takes into account the pulverized coal control amount calculated by the molten iron temperature control in the target value of the pulverized coal ratio.

10. The determination unit adds a plurality of statements to the reason statement, The molten iron temperature control apparatus according to claim 7 or 8, wherein the plurality of statements include a plurality of change contents arranged in order of the most recent change from the current time or the largest change amount.

11. the operation information is an operation amount presentation screen having a statement expressing an intention of the optimal action, a reason for calculating the optimal action, an accept button, and a reject button; the approve button is used when the operator approves the optimal action displayed on the operation amount presentation screen, The molten iron temperature control device according to claim 7 or 8, wherein the non-adopt button is used when the operator does not adopt the optimal action shown on the operation amount presentation screen.

12. the presentation unit has, as a control mode, a semi-automatic mode in which an optimum action is executed with the approval of the operator, and an automatic mode in which an optimum action is executed without the approval of the operator, the operation information is an operation amount presentation screen further having a timer when the control mode is the auto mode, The molten iron temperature control device according to claim 11, wherein the timer displays a time from the time when the display regarding the optimal action is updated to a predetermined specified time, and if the non-adopted button is not selected before the predetermined time is reached, the optimal action is executed.

13. A molten iron temperature control system comprising a molten iron temperature control device and a terminal device, a calculation unit which calculates a pulverized coal ratio manipulated variable by molten iron temperature control so that a molten iron temperature predicted by a physical model capable of calculating a state inside a blast furnace falls within a preset target range, calculates a pulverized coal flow rate manipulated variable by pulverized coal ratio tracking control to compensate for a deviation between a target value of the pulverized coal ratio taking into account the pulverized coal ratio manipulated variable and a current actual value of the pulverized coal ratio, and prioritizes the molten iron temperature control or the pulverized coal ratio tracking control as an optimal action based on the magnitude of discrepancy between the target value of the pulverized coal ratio and the actual value; a determination unit that determines a basis for the calculation of the optimal action and adds a statement to a statement of basis indicating the basis; An output unit that outputs operation information including at least one of the pulverized coal ratio manipulated variable and the pulverized coal flow rate manipulated variable calculated as the optimal action and the reason statement; A communication unit that transmits and receives the operation information; an acquisition unit that acquires the optimum action and the operation information related to the optimum action including the rationale statement; a display unit that displays the acquired optimum action and the operation information so as to include the reason statement; an interface unit that receives instructions for the displayed operation information and outputs a setting value of an operation variable in response to the instructions or based on the passage of a predetermined time.

14. A terminal device constituting a molten iron temperature control system together with a molten iron temperature control device that outputs operation information including at least one of a pulverized coal ratio manipulated variable and a pulverized coal flow rate manipulated variable calculated as an optimal action based on the degree of discrepancy between a target value of the pulverized coal ratio and an actual value of the pulverized coal ratio for controlling the molten iron temperature, and a statement of reasons indicating the reasons for the calculation of the optimal action, an acquisition unit that acquires the optimum action and the operation information related to the optimum action including the rationale statement; a display unit that displays the acquired optimum action and the operation information so as to include the reason statement; an interface unit that receives an instruction for the displayed operation information and outputs a setting value of an operation variable in response to the instruction or based on the passage of a predetermined time.

15. The terminal device according to claim 14 , wherein the operation information includes a plurality of operation conditions and is displayed together with an order of priority.

Images