Method and device for controlling temperature of molten iron, method and device for guiding operation, method for operating blast furnace, and method for producing molten iron

Abstract

The invention provides a molten iron temperature control method and device, an operation guidance method and device, a blast furnace operation method, and a molten iron manufacturing method. The molten iron temperature control method executes: a first control loop for calculating a target value of a pulverized coal ratio so that the molten iron temperature predicted using a physical model capable of calculating the state in a blast furnace falls within a preset target range; and a second control loop that calculates the amount of operation of the pulverized coal flow rate for compensating for the deviation between the target value of the pulverized coal ratio and the actual value of the current pulverized coal ratio.

Description

[0001] This application is a divisional application of the invention patent application with the application date of June 14, 2021, application number 202180047144.0, and invention name "Method and device for controlling molten iron temperature, operation guidance method and device, blast furnace operation method, and molten iron manufacturing method". Technical Field

[0002] The present invention relates to a method for controlling the temperature of molten iron, an operation guidance method, an operation method for a blast furnace, a method for manufacturing molten iron, a device for controlling the temperature of molten iron, and an operation guidance device. Background Art

[0003] In the blast furnace process in the iron and steel industry, the temperature of molten iron is an important management indicator. The temperature of molten iron is mainly controlled by operating the pulverized coal ratio (PCR), which represents the flow rate of pulverized coal per ton of molten iron. In recent years, blast furnace operations have been carried out under conditions of low coke ratio and high pulverized coal ratio in order to rationalize the cost of raw materials and fuels, and the furnace conditions are prone to instability. Therefore, there is a great demand to reduce the unevenness of molten iron temperature.

[0004] In addition, the blast furnace process is operated in a state filled with solids, so the heat capacity of the entire process is large and the time constant of the response to the operation (operation action) is long. In addition, there is a waste time of several hours until the raw materials loaded from the upper part of the blast furnace (furnace top) descend to the lower part of the blast furnace (furnace bottom). Therefore, in order to control the molten iron temperature, it is necessary to appropriately adjust the operation amount of the operation variable based on the future furnace heat prediction.

[0005] Based on this background, a furnace heat prediction method using a physical model is proposed in Patent Document 1. In the furnace heat prediction method described in Patent Document 1, the gas reduction rate parameters included in the physical model are adjusted in a manner consistent with the current composition of the furnace top gas, and the furnace heat is predicted using the physical model after the parameter adjustment.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 11-335710 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, in the conventional method for controlling the temperature of molten iron, there is a problem that the control performance is reduced when the raw material descent speed (feeding) changes due to changes in air permeability. The operator's direct operating variable is the flow rate of pulverized coal blown in from the tuyere [kg / min]. However, even if the pulverized coal flow rate is constant, if the production speed of molten iron (hereinafter referred to as "ironmaking speed") [t / min] changes, the pulverized coal ratio (PCR) calculated by the ratio of the pulverized coal flow rate to the ironmaking speed will also change, causing changes in the molten iron temperature.

[0011] The ironmaking speed is roughly proportional to the oxygen flow rate supplied to the furnace, but even if the oxygen flow rate is constant, the bulk density of the raw material will temporarily decrease when the air permeability in the furnace deteriorates, and the material feeding will become slow. In such a case, the control accuracy of the molten iron temperature control method using the conventional physical model is reduced.

[0012] The present invention has been completed in view of the above situation, and its purpose is to provide a control method for molten iron temperature, an operation guidance method, a blast furnace operation method, a molten iron manufacturing method, a molten iron temperature control device and an operation guidance device that are not easily affected by changes in material feeding caused by changes in permeability.

[0013] Means for solving problems

[0014] In order to solve the above-mentioned problems and achieve the purpose, the method for controlling the molten iron temperature of the present invention executes: a first control loop to calculate the target value of the pulverized coal ratio in such a way that the molten iron temperature predicted by a physical model capable of calculating the state inside the blast furnace is within a preset target range; and a second control loop to calculate the operating amount of the pulverized coal flow rate for compensating for the deviation between the target value of the pulverized coal ratio and the current actual value of the pulverized coal ratio.

[0015] In addition, the method for controlling molten iron temperature involved in the present invention includes: a free response calculation step, wherein the first control loop uses the physical model to calculate the free response, and the free response represents the response of the molten iron temperature when the operation amount of all the operating variables among the pre-set multiple operating variables is constant during a specified period; a step response calculation step, wherein the physical model is used to calculate the step response, and the step response represents the response of the molten iron temperature when the operation amount of the pulverized coal ratio among the multiple operating variables is changed in a step-like manner by a unit amount; a PCR operation amount calculation step, wherein the operation amount of the pulverized coal ratio used to make the molten iron temperature within the target range is calculated based on the free response and the step response; and a PCR target value calculation step, wherein the target value of the pulverized coal ratio is calculated by adding the operation amount of the pulverized coal ratio to the current target value of the pulverized coal ratio.

[0016] In addition, the method for controlling the molten iron temperature involved in the present invention includes: a pulverized coal ratio deviation calculation step, wherein the second control loop calculates the deviation of the pulverized coal ratio based on the target value of the pulverized coal ratio calculated by the first control loop, the actual value of the pulverized coal ratio and the performance value of the ironmaking speed calculated in advance; and a PCI operation amount calculation step, wherein the operation amount of the pulverized coal flow rate is calculated based on the deviation of the pulverized coal ratio and the performance value of the ironmaking speed.

[0017] In addition, the method for controlling molten iron temperature involved in the present invention is based on the above invention. In the PCR operation amount calculation step, the operation amount of the pulverized coal ratio is calculated in such a way that the predicted value of the molten iron temperature after the specified period when the operation amounts of all the multiple operation variables are constant during the specified period is included in the upper and lower limits of the molten iron temperature set in advance.

[0018] In addition, the method for controlling the molten iron temperature involved in the present invention is based on the above invention, and the actual value of the ironmaking speed is calculated based on the raw materials put into the blast furnace from the time point of calculating the operation amount to a specified time before, or the hot air blown in from the tuyere of the blast furnace and the gas coming out from the furnace top.

[0019] In order to solve the above-mentioned problems and achieve the object, the operation guidance method according to the present invention includes the step of supporting the operation of a blast furnace by presenting the operation amount of the pulverized coal flow rate calculated by the above-mentioned method for controlling the molten iron temperature.

[0020] In order to solve the above-mentioned problems and achieve the object, the method for operating a blast furnace according to the present invention includes the step of controlling the blast furnace according to the operation amount of the pulverized coal flow rate calculated by any of the above-mentioned methods for controlling the molten iron temperature.

[0021] To solve the above problems and achieve the object, the method for producing molten iron according to the present invention includes the step of controlling a blast furnace according to the operation amount of pulverized coal flow rate calculated by the above method for controlling molten iron temperature to produce molten iron.

[0022] In order to solve the above-mentioned problems and achieve the purpose, the control device of molten iron temperature involved in the present invention comprises a unit for executing a first control loop and a second control loop, wherein the first control loop calculates a target value of the pulverized coal ratio in such a way that the molten iron temperature predicted by a physical model capable of calculating the state inside a blast furnace is within a predetermined target range, and the second control loop calculates an operating amount of the pulverized coal flow rate for compensating for the deviation between the target value of the pulverized coal ratio and a current actual value of the pulverized coal ratio.

[0023] In order to solve the above-mentioned problems and achieve the object, an operation guidance device according to the present invention includes means for supporting the operation of a blast furnace by presenting an operation amount of a pulverized coal flow rate calculated by the above-mentioned molten iron temperature control device.

[0024] Effects of the Invention

[0025] According to the molten iron temperature control method, operation guidance method, blast furnace operation method, molten iron manufacturing method, molten iron temperature control device and operation guidance device of the present invention, the molten iron temperature can be controlled without being affected by the change of the material discharge caused by the change of the permeability. Therefore, efficient and stable operation of the blast furnace can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a block diagram showing a schematic configuration of a molten iron temperature control device according to an embodiment of the present invention.

[0027] Figure 2 This is a diagram showing an example of input variables and output variables of a physical model used in the method for controlling the molten iron temperature according to the embodiment of the present invention.

[0028] Figure 3 It is a diagram showing the structure of a control loop in the method for controlling the molten iron temperature according to the embodiment of the present invention.

[0029] Figure 4 This is a diagram showing the prediction result of the molten iron temperature by the physical model in the molten iron temperature control method according to the embodiment of the present invention.

[0030] Figure 5 This is a diagram showing a step response of the molten iron temperature with respect to a change in the pulverized coal ratio in the molten iron temperature control method according to the embodiment of the present invention.

[0031] Figure 6 The figure shows the result of applying the control method of the molten iron temperature involved in the embodiment of the present invention to the actual operation of the blast furnace. Specifically, the figure shows the deviation of the actual value of the molten iron temperature from the target value, the operation amount of the pulverized coal ratio by the control and the operator, the transition of the target value and the actual value of the pulverized coal ratio, and the operation amount of the pulverized coal flow rate by the control and the operator. DETAILED DESCRIPTION

[0032] Regarding the method for controlling the temperature of molten iron, the operation guidance method, the method for operating a blast furnace, the method for producing molten iron, the device for controlling the temperature of molten iron, and the operation guidance device according to the embodiments of the present invention, with reference to the attached drawings, Figure 1 Side description.

[0033] [Structure of the device for controlling the temperature of molten iron]

[0034] First, with reference to the structure of the control device for the temperature of molten iron according to the embodiment of the present invention (hereinafter referred to as "control device"), Figure 1The control device 100 includes an information processing device 101 , an input device 102 , and an output device 103 .

[0035] The information processing device 101 is a general-purpose device such as a personal computer or a workstation, and includes a RAM 111, a ROM 112, and a CPU 113. The RAM 111 temporarily stores processing programs and processing data related to processing executed by the CPU 113, and functions as a work area for the CPU 113.

[0036] The ROM 112 stores a control program 112 a for executing the method for controlling the molten iron temperature according to the embodiment of the present invention, a processing program for controlling the overall operation of the information processing device 101 , and processing data.

[0037] The CPU 113 controls the overall operation of the information processing device 101 according to the control program 112a and the processing program stored in the ROM 112. In the method for controlling the temperature of molten iron described later, the CPU 113 functions as a free response calculation unit for performing a free response calculation step, a step response calculation unit for performing a step response calculation step, and a PCR operation amount calculation unit for performing a PCR operation amount calculation step. In addition, the CPU 113 functions as a PCR target value calculation unit for performing a PCR target value calculation step, a pulverized coal ratio deviation calculation unit for performing a pulverized coal ratio deviation calculation step, a PCI operation amount calculation unit for performing a PCI operation amount calculation step, and a PCI setting value calculation unit for performing a PCI setting value calculation step.

[0038] The input device 102 is composed of a keyboard, a mouse pointer, a keypad, etc., and is operated to input various information to the information processing device 101. The output device 103 is composed of a display device, a printer, etc., and outputs various processing information of the information processing device 101.

[0039] [Structure of physical model]

[0040] Next, the physical model used in the method for controlling the molten iron temperature involved in the embodiment of the present invention is described. The physical model used in the present invention is the same as the method described in Reference 1 (Michiharu Hanedano et al.: "Study of furnace opening operation based on the unstable model of blast furnace", Iron and Steel, vol. 68, p. 2369), and is composed of a group of partial differential equations that take into account multiple physical phenomena such as the reduction of iron ore, the heat exchange between iron ore and coke, and the melting of iron ore. In addition, the physical model used in the present invention is a physical model (hereinafter referred to as an "unstable model") that can calculate variables (output variables) representing the state of the blast furnace in an unstable state.

[0041] like Figure 2As shown, among the boundary conditions provided for the unstable model, the main boundary conditions (input variables, operating variables (also called operating factors) of the blast furnace) that vary with time are as follows.

[0042] (1) Coke ratio at furnace top (CR) [kg / t]: The amount of coke input per ton of molten iron

[0043] (2) Air flow (BV) [Nm 3 / min]: Flow rate of air blown into the blast furnace

[0044] (3) Oxygen enrichment flow (BVO) [Nm 3 / min]: Flow rate of oxygen-enriched gas blown into the blast furnace

[0045] (4) Air supply temperature (BT) [°C]: The temperature of the air blown into the blast furnace

[0046] (5) Pulverized coal flow rate (coal powder injection, PCI) [kg / min]: The weight of pulverized coal used per ton of molten iron produced

[0047] (6) Wet air content (BM) [g / Nm 3 ]: Humidity of air blown into the blast furnace

[0048] In addition, the main output variables formed by the unstable model are as follows.

[0049] (1) Gas utilization rate in the furnace (ηCO): CO2 / (CO+CO2)

[0050] (2) Temperature of coke and iron

[0051] (3) Oxidation degree of iron ore

[0052] (4) Raw material descent speed

[0053] (5) Dissolved carbon loss (dissolved carbon loss)

[0054] (6) Molten iron temperature

[0055] (7) Ironmaking speed (molten iron generation speed)

[0056] (8) Heat loss from furnace: The amount of heat lost by cooling water when the furnace is cooled.

[0057] In the present invention, the time step (time interval) when calculating the output variable is set to 30 minutes. However, the time step can be changed according to the purpose and is not limited to the value of this embodiment. By using this unsteady model, the output variables including the molten iron temperature and ironmaking speed that change at all times are calculated.

[0058] 〔Control loop〕

[0059] Next, the control loop executed in the method for controlling the temperature of molten iron according to the present embodiment is described. In the method for controlling the temperature of molten iron according to the present embodiment, Figure 3 As shown, a dual control loop consisting of a first control loop (HMT control loop) and a second control loop (PCR control loop) is executed. In the first control loop, the target value of the pulverized coal ratio (target PCR) is calculated in such a way that the molten iron temperature predicted by the unsteady model capable of calculating the state in the blast furnace is within a pre-set target range (target HMT). In addition, in the second control loop, the operating amount of the pulverized coal flow rate is calculated to compensate for the deviation between the target value of the pulverized coal ratio (target PCR) and the actual value of the current pulverized coal ratio (actual PCR).

[0060] 〔Method for controlling molten iron temperature〕

[0061] Next, the method for controlling the molten iron temperature of the present embodiment using the above-mentioned unstable model is described. The method for controlling the molten iron temperature of the present embodiment sequentially performs a free response calculation step, a step response calculation step, a PCR operation amount calculation step, a PCR target value calculation step, a pulverized coal ratio deviation calculation step, a PCI operation amount calculation step, and a PCI set value calculation step. The above-mentioned unstable model can be expressed, for example, as shown in the following equations (1) and (2).

[0062]

[0063]

[0064] Here, in the above equations (1) and (2), x(t) is the state variable (temperature of coke and iron, oxidation degree of iron ore, falling speed of raw materials, etc.) calculated in the unsteady model, and y(t) is the molten iron temperature (Hot Metal Temperature: HMT) as the control variable. In addition, C is a matrix or function for extracting the control variable from the state variable calculated in the unsteady model.

[0065] In addition, u(t) in the above formula (1) is an input variable of the unsteady model, which is the air flow rate, oxygen enrichment flow rate, pulverized coal flow rate, air moisture content, air temperature and coke ratio. This u(t) can be expressed by "u(t) = (BV(t), BVO(t), PCI(t), BM(t), BT(t), CR(t))".

[0066] (Free response calculation procedure)

[0067] First, assuming that the current operation amounts of all the operation variables are kept constant, the prediction calculation of the future molten iron temperature HMT is performed. That is, in this step, the above-mentioned unstable model is used to calculate the response of the molten iron temperature HMT when the operation amounts of all the operation variables among the pre-set multiple operation variables (input variables) are constant during a specified period. In this step, specifically, the current time step is set to t=0, and the future molten iron temperature HMT is calculated using the following equations (3) and (4). In addition, in the case where there is an estimated error between the estimated value of the molten iron temperature at the current time point by the unstable model and the actual molten iron temperature at the current time point, the following processing can also be performed as needed. That is, it is also possible to implement a correction to eliminate the bias error with the actual value by adding the estimated error to the calculated value of the unstable model.

[0068]

[0069]

[0070] In this embodiment, the response y0 of the controlled variable (here, the molten iron temperature) obtained in this way is called a "free response". Figure 4 An example of the prediction results of a part of the operating variables (input variables) (coke ratio CR, pulverized coal flow rate PCI, air humidity fraction BM) and the molten iron temperature HMT is shown in FIG. It should be noted that the calculated value of the molten iron temperature HMT in the past interval is calculated using the actual operating variables in the past.

[0071] (Step response calculation procedure)

[0072] In this step, the above-mentioned unsteady model is used to calculate a step response showing the response of the molten iron temperature HMT when the manipulated variable of the pulverized coal ratio among a plurality of manipulated variables (input variables) is changed stepwise by a unit amount.

[0073] Here, the free response Y0 of the molten iron temperature HMT obtained in the free response calculation step is calculated as Figure 5 (b) is shown by the solid line. In this step, Figure 5 As shown by the dotted line in (a), the response of the molten iron temperature HMT when the pulverized coal ratio PCR is increased by 10 kg / t at time 0 while maintaining other manipulated variables is calculated using the following equations (5) and (6).

[0074]

[0075]

[0076] The increase in the pulverized coal flow rate PCI is obtained by multiplying the increase in the pulverized coal ratio PCR by the current ironmaking speed. In the above formula (5), the operation of increasing the pulverized coal flow rate PCI is denoted by Δu1. The response y1 of the molten iron temperature HMT shown in this step is expressed as Figure 5 (b) is shown by the dotted line.

[0077] Next, by obtaining the response y1 (refer to Figure 5 The step response of the molten iron temperature HMT to the change of the pulverized coal ratio PCR is calculated by comparing the difference between the dotted line in (b) and the free response y0 of the molten iron temperature HMT (see the solid line in the figure). Here, the output is divided by 10 to set it as a step response to a unit amount.

[0078] (PCR operation volume calculation steps)

[0079] Next, the operation range of the pulverized coal ratio PCR is determined so that the future molten iron temperature HMT is within the target range (target HMT). That is, in this step, the operation amount ΔPCR of the pulverized coal ratio for making the molten iron temperature HMT within the target range is calculated based on the free response obtained in the free response calculation step and the step response obtained in the step response calculation step.

[0080] In this step, in order to avoid excessive operating actions while keeping the molten iron temperature HMT within the target range, the operating amount ΔPCR of the pulverized coal ratio is calculated as shown in the following formula (7). That is, the operating amount ΔPCR of the pulverized coal ratio is calculated in such a way that the predicted value of the molten iron temperature HMT after a specified period of time when the operating amounts of all operating variables among a plurality of operating variables (input variables) are constant during a specified period is included in the upper and lower limits of the molten iron temperature HMT set in advance. It should be noted that since the time required from the input of iron ore into the furnace to the discharge of iron ore out of the furnace is about 8 hours, the prediction interval of the molten iron temperature HMT in the following formula (7) is set to 10 hours. In addition, in order to simplify the control logic, the control interval is set to 1 step.

[0081]

[0082] In the above formula (7), T 10 pre is the predicted value of the molten iron temperature HMT after 10 hours, T U is the upper limit of the molten iron temperature HMT, T L is the lower limit of the molten iron temperature HMT, S 10 PCR is the value after 10 hours of the step response of the molten iron temperature HMT to the change in the pulverized coal ratio PCR. By setting such a control law, at T 10pre While the pulverized coal ratio is within the target range, the operation amount ΔPCR of the pulverized coal ratio becomes zero, so the operator's workload associated with the change in the operation amount can be reduced.

[0083] (PCR target value calculation step)

[0084] Next, as shown in the following formula (8), the operation amount ΔPCR of the coal powder ratio obtained in the PCR operation amount calculation step is divided into the target value PCR of the coal powder ratio currently managed by the operator. 0 ref Add them together to calculate the target value of the coal powder ratio PCR ref The above description is equivalent to Figure 3 The first control loop (HMT control loop).

[0085]

[0086] (Calculation steps of pulverized coal ratio deviation)

[0087] In this step, the target value PCR of the coal powder ratio obtained in the PCR target value calculation step is calculated. ref Deviation from the actual value of the current pulverized coal ratio (deviation of the pulverized coal ratio).

[0088] Here, in order to calculate the current performance value of the pulverized coal ratio (performance PCR), it is necessary to find the ratio of the performance value of the pulverized coal flow rate to the performance value of the ironmaking speed. As methods for finding the ironmaking speed, there are methods such as a method of finding it using the oxygen balance, a method of finding it using the pig iron equivalent amount of iron oxide contained in the raw material layer (charge) fed into the blast furnace, etc. For example, when finding the ironmaking speed based on the oxygen balance, the ironmaking speed can be found by finding the difference between the amount of oxygen contained in the hot air blown in from the tuyere of the blast furnace and the amount of oxygen contained in the gas discharged from the furnace top.

[0089] In this embodiment, based on the pig iron equivalent amount of iron oxide contained in the raw material layer (charge) charged to the blast furnace, the actual value of the current pulverized coal ratio is calculated according to the frequency of raw material charging in the most recent 8 charges. That is, if the number of the charge currently being charged is N, the number of raw material layers existing in the furnace is A, the charging start time of the i-th charge is Time[i], and the pig iron equivalent amount is Pig[i], the current ironmaking speed Prod(t) can be calculated by the following formula (9).

[0090]

[0091] Here, the pig iron conversion amount Pig in the above formula (9) more specifically represents the weight of the part converted into pig iron relative to the weight of the raw materials put into the blast furnace. In addition, in the above formula (9), the number of raw material layers is traced back to the A layer in the past in order to use the amount of pig iron contained in the raw material layer at the tuyere height to calculate the ironmaking speed. As shown in the above formula (9), by dividing the amount of pig iron put into the blast furnace by the time required to load the raw materials of the most recent 8 charges, the amount of pig iron put in during this time, that is, the ironmaking speed, can be calculated. The ironmaking speed varies greatly if calculated based on the actual performance value in a short period of time, so it is preferably smoothed using a period in the range of about 1 to 3 hours. Here, it is set to the average of 8 charges, but in normal operation it is equivalent to about 2 hours.

[0092] Next, the target value of the coal powder ratio PCR ref The deviation δPCR from the actual value of the current pulverized coal ratio is calculated by the following formula (10).

[0093]

[0094] (PCI operation amount calculation steps)

[0095] In this step, when a deviation δPCR of the pulverized coal ratio occurs, the operation amount ΔPCI of the pulverized coal flow rate for compensating for the deviation δPCR is calculated by the following equation (11).

[0096]

[0097] (PCI setting value calculation steps)

[0098] In this step, the set value of the pulverized coal flow rate (set PCI) is calculated by adding the pulverized coal flow rate operation amount ΔPCI obtained in the PCI operation amount calculation step to the current set value of the pulverized coal flow rate. Figure 3 The second control loop (PCR control loop) is used. Through the above processing, the operation of the appropriate pulverized coal flow rate PCI for controlling the molten iron temperature HMT can be realized. In addition, even if the feeding changes due to changes in permeability, the PCR control loop composed of the above formulas (9) to (11) can be used to suppress the changes in the pulverized coal ratio PCR, thereby reducing the unevenness of the molten iron temperature HMT.

[0099] [Example]

[0100] Figure 6 This is an example showing the result of applying the method for controlling the molten iron temperature according to the present embodiment to the actual operation of a blast furnace. Figure 6(a) shows the deviation of the actual value of the molten iron temperature from the target value. In this figure, the solid line represents the actual value of the molten iron temperature (actual value HMT), and the dotted line represents the target value of the molten iron temperature (target HMT). Figure 6 (b) shows the comparison result of the operation amount ΔPCR of the present control on the pulverized coal ratio and the operation amount of the pulverized coal ratio of the actual operation result of the operator. In this figure, the triangle marks represent the operation of the present control, and the circle marks represent the operation of the operator.

[0101] in addition, Figure 6 (c) shows the comparison results of the target value and the actual value of the pulverized coal ratio. In this figure, the dotted line represents the actual value (actual PCR) of the pulverized coal ratio, and the solid line represents the target value (target PCR) of the pulverized coal ratio. In addition, the vertical axis of the figure represents the deviation from the typical value of the pulverized coal ratio. As the "typical value of the pulverized coal ratio", the average value of the pulverized coal ratio during normal operation of the blast furnace can be used.

[0102] in addition, Figure 6 (d) shows the comparison result of the operation amount ΔPCI of the pulverized coal flow rate of the present control and the operation amount of the pulverized coal flow rate of the operator in the same manner as before. In this figure, the triangle marks represent the operation of the present control, and the circle marks represent the operation of the operator. Figure 6 (b) and Figure 6 The "main control" in (d) is not completely automatic control, but is the result of experiments in the form of guidance to the operator.

[0103] like Figure 6 As shown in (a), the operator can make the molten iron temperature close to the target value by operating roughly as instructed. Figure 6 Part A of (b) and Figure 6 As shown in the B part of (d), during the period from 11:00 to 12:00, the pulverized coal flow rate is reduced together with the pulverized coal ratio. As a result of the operator's operation based on this control, the molten iron temperature is maintained near the target value.

[0104] In addition, if Figure 6 Part C of (b) and Figure 6 As shown in the D part of (d), during the period from 18:00 to 20:00, even if the operation amount ΔPCR of the pulverized coal ratio is zero, the operation amount ΔPCI of the pulverized coal flow rate is output. Figure 6 As shown in the E part of (c), the pulverized coal ratio PCR is maintained near the target value. Figure 6 As shown in the F portion of (a), the variation of the molten iron temperature is suppressed. As described above, the usefulness of the molten iron temperature control method according to the present embodiment in actual operation is demonstrated.

[0105] [Operational guidance method]

[0106] The method for controlling the molten iron temperature of the present embodiment can also be applied to an operation guidance method. In this case, in addition to the free response calculation step, step response calculation step, PCR operation amount calculation step, PCR target value calculation step, pulverized coal ratio deviation calculation step, and PCI operation amount calculation step in the aforementioned method for controlling the molten iron temperature, the following step is also performed. That is, a step of supporting the operation of the blast furnace by prompting the operator with the operation amount ΔPCI of the pulverized coal flow calculated in the PCI operation amount calculation step, for example, via the output device 103.

[0107] 〔How to operate a blast furnace〕

[0108] The method for controlling the temperature of molten iron according to the present embodiment can also be applied to a method for operating a blast furnace. In this case, in addition to the free response calculation step, step response calculation step, PCR operation amount calculation step, PCR target value calculation step, pulverized coal ratio deviation calculation step, and PCI operation amount calculation step in the aforementioned method for controlling the temperature of molten iron, the following step is also performed. That is, a step of controlling the blast furnace according to the operation amount ΔPCI of the pulverized coal flow calculated in the PCI operation amount calculation step is performed.

[0109] [Method for producing molten iron]

[0110] The method for controlling the temperature of molten iron according to the present embodiment can also be applied to a method for manufacturing molten iron. In this case, in addition to the free response calculation step, step response calculation step, PCR operation amount calculation step, PCR target value calculation step, pulverized coal ratio deviation calculation step, and PCI operation amount calculation step in the aforementioned method for controlling the temperature of molten iron, the following step is also performed. That is, a step of controlling a blast furnace according to the operation amount ΔPCI of the pulverized coal flow rate calculated in the PCI operation amount calculation step to thereby manufacture molten iron is performed.

[0111] According to the above-described method for controlling the temperature of molten iron, the method for operating a blast furnace, the method for manufacturing molten iron, the device for controlling the temperature of molten iron, and the device for operating the temperature of molten iron, the temperature of molten iron can be controlled without being affected by the change in the material discharge caused by the change in the air permeability. Therefore, the blast furnace can be operated efficiently and stably.

[0112] In addition, in the conventional method for controlling the temperature of molten iron, for example, the method only stops at providing guidance on the pulverized coal ratio, and the operator controls the pulverized coal flow rate according to the guidance. On the other hand, in the method for controlling the temperature of molten iron according to the present embodiment, a dual structure control loop consisting of an HMT control loop and a PCR control loop can be used (see Figure 3 ) is used to calculate the operating amount of the pulverized coal flow rate, thereby enabling automatic control of the molten iron temperature.

[0113] The above specifically describes the method for controlling the temperature of molten iron, the method for operating a blast furnace, the method for manufacturing molten iron, the device for controlling the temperature of molten iron, and the device for operating the temperature of molten iron, using the methods and embodiments for implementing the invention, but the gist of the present invention is not limited to these records and must be interpreted broadly based on the records of the claims. In addition, the techniques obtained by various changes and modifications based on these records are of course also included in the gist of the present invention.

[0114] Description of Reference Numerals

[0115] 100 Control device

[0116] 101 Information processing device

[0117] 102 Input Device

[0118] 103 Output device

[0119] 111 RAM

[0120] 112 ROM

[0121] 112a Control Program

[0122] 113 CPU.

Claims

1. A method for controlling the temperature of molten iron, comprising: The first control loop calculates a target value of the pulverized coal ratio so that the molten iron temperature predicted by a physical model capable of calculating the state in the blast furnace is within a preset target range; and The second control loop calculates an operation amount of the pulverized coal flow rate for compensating for a deviation between the target value of the pulverized coal ratio and the actual value of the current pulverized coal ratio, The second control loop comprises: a pulverized coal ratio deviation calculation step of calculating a pulverized coal ratio deviation based on the target value of the pulverized coal ratio calculated by the first control loop, an actual value of the pulverized coal flow rate, and an actual value of the ironmaking speed calculated in advance; and The PCI operation amount calculation step calculates the operation amount of the pulverized coal flow rate based on the deviation of the pulverized coal ratio and the actual value of the ironmaking speed.

2. The method for controlling the temperature of molten iron according to claim 1, The first control loop comprises: A free response calculation step of calculating a free response using the physical model, the free response indicating a response of the molten iron temperature when the manipulated amounts of all manipulated variables among a plurality of preset manipulated variables are constant over a predetermined period; a step response calculation step of calculating a step response using the physical model, the step response indicating a response of the molten iron temperature when the operation amount of the pulverized coal ratio among the plurality of operation variables is changed stepwise by a unit amount; a PCR operation amount calculation step of calculating an operation amount of the pulverized coal ratio for making the molten iron temperature fall within the target range based on the free response and the step response; and The PCR target value calculation step calculates the target value of the pulverized coal ratio by adding the operation amount of the pulverized coal ratio to the current target value of the pulverized coal ratio.

3. The method for controlling the temperature of molten iron according to claim 2, In the PCR operation amount calculation step, the operation amount of the pulverized coal ratio is calculated in such a way that the predicted value of the molten iron temperature after the specified period when the operation amounts of all the multiple operation variables are constant during the specified period is included in the upper and lower limits of the molten iron temperature set in advance.

4. The method for controlling the temperature of molten iron according to claim 1, The actual value of the ironmaking speed is calculated based on the raw materials charged into the blast furnace or the hot air blown from the tuyere of the blast furnace and the gas discharged from the furnace top from the time when the operation amount is calculated to a predetermined time ago.

5. An operation guidance method, The method comprises the step of supporting the operation of the blast furnace by presenting the operation amount of the pulverized coal flow rate calculated by the method for controlling the molten iron temperature according to any one of claims 1 to 4.

6. A method for operating a blast furnace, The method comprises the step of controlling a blast furnace according to the operation amount of the pulverized coal flow rate calculated by the method for controlling the molten iron temperature according to any one of claims 1 to 4.

7. A method for producing molten iron, The method comprises the step of controlling a blast furnace according to the operation amount of the pulverized coal flow rate calculated by the method for controlling the molten iron temperature according to any one of claims 1 to 4, thereby producing molten iron.

8. A device for controlling the temperature of molten iron, A unit is provided for executing a first control loop and a second control loop, The first control loop calculates a target value of the pulverized coal ratio so that the molten iron temperature predicted by a physical model capable of calculating the state in the blast furnace is within a preset target range. The second control loop calculates the operation amount of the pulverized coal flow rate for compensating for the deviation between the target value of the pulverized coal ratio and the actual value of the current pulverized coal ratio. The second control loop calculates a deviation of the pulverized coal ratio based on the target value of the pulverized coal ratio calculated by the first control loop, an actual value of the pulverized coal flow rate, and an actual value of the ironmaking speed calculated in advance; The second control loop calculates the operation amount of the pulverized coal flow rate based on the deviation of the pulverized coal ratio and the actual value of the ironmaking speed.

9. An operation guidance device, A means for supporting the operation of the blast furnace by presenting the operation amount of the pulverized coal flow rate calculated by the molten iron temperature control device according to claim 8 is provided.

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