Blast furnace control methods, molten iron manufacturing methods, blast furnace operation methods, blast furnace control devices, blast furnace operation simulation devices, input / display terminal devices, blast furnace control systems

Abstract

To provide a blast furnace control method, a method for manufacturing molten iron, a method for operating a blast furnace, a blast furnace control device, a blast furnace operation simulation device, an input / display terminal device, and a blast furnace control system that enable operators to derive optimal actions for achieving low CO2 emissions and low operating costs by considering the conditions inside the furnace. [Solution] The blast furnace control method includes: a first prediction step of predicting the changes in control variables when the current operating conditions are maintained; a second prediction step of predicting the changes in control variables when the furnace is operated under arbitrary hypothetical operating conditions; a display step of displaying the time-based mass balance and heat balance, including oxygen, carbon, and hydrogen in the blast furnace, along with the control variables, as a single graph on an input / display terminal device, based on the changes in the control variables predicted in the first and second prediction steps; and a control output step of transmitting the input operating conditions as manipulated variable command values.

Description

[Technical Field]

[0001] This invention relates to a blast furnace control method, a method for manufacturing molten iron, a blast furnace operation method, a blast furnace control device, a blast furnace operation simulation device, an input / display terminal device, and a blast furnace control system. [Background technology]

[0002] The blast furnace process is the main pig iron production process in the steel industry and is characterized by its excellent thermal efficiency. In a blast furnace, iron ore and coke are fed in from the top of the furnace. As they descend towards the bottom of the furnace, they are heated by hot air at approximately 1200°C and pulverized coal blown in from about 40 tuyeres located at the bottom of the furnace. In this process, the iron oxide in the iron ore is reduced by the carbon contained in the coke and pulverized coal, and molten iron at approximately 1500°C and slag, a by-product, are discharged from the bottom of the furnace.

[0003] The main control variables in blast furnace operation, as shown in Figure 1, are the temperature of molten iron discharged from the bottom of the furnace (HMT), the production rate (Prod), the pressure drop (ΔP), and the CO2 emissions (CO2). In addition, in blast furnace operation, operational variables such as the coke ratio (CR) at the top of the furnace, the pulverized coal flow rate (PCI), the moisture content of the blown air (BM), and the blown air flow rate (BV) are manipulated to control these control variables. Figure 2 shows the direction of change for each control variable when each operational variable is increased.

[0004] In blast furnace operation, it is necessary to maintain a constant molten iron temperature. If the molten iron temperature rises too high, not only is excess reducing agent consumed, but the expansion of furnace gases makes the raw material descent unstable. On the other hand, if the molten iron temperature drops too low, the slag removal efficiency deteriorates, and the productivity of the blast furnace decreases significantly. Therefore, operators mainly manipulate the blown air moisture content and the pulverized coal ratio to control the molten iron temperature. The pulverized coal ratio indicates the flow rate of pulverized coal per ton of molten iron.

[0005] Furthermore, blast furnace operation requires adherence to a predetermined production rate demanded by the subsequent steelmaking process. The production rate is controlled by the rate at which iron ore is charged into the furnace from the top. Failure to meet the target production rate leads to economic losses. In addition, if production is excessive, molten iron will accumulate before being charged into the converter in the next process, causing the temperature to drop. This means that excess carbon material will be needed to raise the temperature in the next process, leading to an increase in CO2 emissions.

[0006] In recent years, blast furnace operations have favored lower coke ratios to reduce operating costs, leading to chronic increases in pressure loss. This has resulted in frequent occurrences of a problem called "blow-through," where hot air blows up locally, making stable operation difficult. Furthermore, the high-temperature gas blow-through can damage the furnace top equipment, sometimes leading to prolonged operational shutdowns. Therefore, stabilizing the gas flow is extremely important. Measures to improve permeability include reducing gas velocity by decreasing the airflow rate and ensuring coke slits by increasing the coke ratio.

[0007] As described above, in blast furnace processes, it is necessary to operate while maintaining the molten iron temperature and production rate at predetermined target values, and while preventing the gas flow from becoming unstable. Furthermore, in recent blast furnace operations, in order to reduce CO2 emissions and operating costs, there is a simultaneous demand for reducing the reducing agent ratio and the coke ratio. A decrease in the reducing agent ratio leads to a decrease in the molten iron temperature, and a decrease in the coke ratio leads to instability of the gas flow. It is necessary to continue stable operations while demanding low CO2 emissions and low operating costs.

[0008] Because blast furnace processes operate with a solid core, they have a large overall heat capacity and a long time constant for responding to operational actions. Furthermore, there is a dead time of several hours before the raw materials charged into the upper part of the furnace descend to the lower part. Therefore, in order to operate a blast furnace properly, it is necessary to calculate actions based on future predictions.

[0009] For example, Patent Document 1 discloses a method for operating a blast furnace by calculating actions based on future predictions using a physical model. However, there are elements in the furnace reaction that are difficult to model accurately (for example, discontinuous phenomena such as localized gas blow-throughs caused by the pulverization of raw materials), and complete automation has not yet been achieved. In addition, if the operation of the blast furnace, which is an upstream process in the steelworks, is stopped, the entire steelworks will be paralyzed, resulting in significant economic losses. Therefore, automation with human intervention is considered desirable.

[0010] Therefore, Patent Document 2 discloses a method that encourages operators to derive appropriate operational actions by considering the conditions inside the furnace, by presenting information on the heat and mass balance based on a physical model. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 11-335710 [Patent Document 2] Japanese Patent Publication No. 2022-14169 [Overview of the project] [Problems that the invention aims to solve]

[0012] In the method disclosed in Patent Document 2, only the molten iron temperature and production rate are treated as control variables, and a problem arises because pressure loss, which is an indicator of gas flow stability, and CO2 emissions, which have become increasingly important for the steel industry in recent years, are not treated as control variables.

[0013] The present invention has been made in view of the above, and aims to provide a blast furnace control method, a method for manufacturing molten iron, a method for operating a blast furnace, a blast furnace control device, a blast furnace operation simulation device, an input / display terminal device, and a blast furnace control system that enable an operator to derive the optimal action for achieving blast furnace operation with low CO2 emissions and low operating costs, taking into account the conditions inside the furnace. [Means for solving the problem]

[0014] To solve the above-mentioned problems and achieve the objective, the blast furnace control method according to the present invention includes: a first prediction step in which a first prediction unit of a computer predicts the trend of one or more control variables among molten iron temperature, production rate, permeability index, and CO2 emission index when the current operating conditions are maintained, using a blast furnace physical model; a second prediction step in which a second prediction unit of the computer predicts the trend of one or more control variables among molten iron temperature, production rate, permeability index, and CO2 emission index when the operation is performed under arbitrary hypothetical operating conditions input by the operator; a display step in which an output unit of the computer displays the time-based mass balance and heat balance, including oxygen, carbon, and hydrogen in the blast furnace, when the trends of the control variables are predicted in the first prediction step and the second prediction step, together with the control variables, as a single graph on an input / display terminal device; and a control output step in which the input operating conditions are transmitted as manipulated variable command values.

[0015] In the blast furnace control method according to the present invention, the display step displays the changes in the control variables predicted in the first prediction step and the changes in the control variables predicted in the second prediction step side by side with the graph.

[0016] The blast furnace control method according to the present invention includes, in the above invention, at least one of the operating conditions, the coke ratio at the top of the furnace, the blast flow rate, the pulverized coal flow rate, and the blast moisture content, and the display step displays the changes in the operating conditions alongside the graph.

[0017] In the blast furnace control method according to the present invention, the mass balance includes the amount of reducing gas produced in the lower part of the furnace, the mass balance of carbon and oxygen, and the carbon balance derived from coke throughout the furnace.

[0018] The blast furnace control method according to the present invention further includes a balance calculation step in which the carbon intensity of each is calculated by dividing the amount of carbon supplied from coke and the amount of carbon supplied from pulverized coal included in the material balance by the production rate, and the display step displays the carbon intensity of coke and the carbon intensity of pulverized coal on the graph in relation to the amount of carbon supplied from coke, the amount of carbon supplied from pulverized coal, and the production rate.

[0019] The blast furnace control method according to the present invention, in the above invention, displays on the graph a first line segment showing nitrogen contained in the blown air as the mass balance, a second line segment showing the flow rate of the top gas, a third line segment showing the pressure loss inside the furnace which is the permeability index and is perpendicular to the second line segment, and the slope of a fourth line segment showing the resistance of the gas flow inside the furnace, obtained by dividing the flow velocity of the top gas by the pressure loss.

[0020] In the blast furnace control method according to the present invention, the display step displays the material balance and the heat balance converted to per unit weight of iron using the production rate side by side on a single graph.

[0021] In the blast furnace control method according to the present invention, the second prediction step can be repeatedly performed by changing the manipulated variable, and the display step is performed after the second prediction step is performed.

[0022] In the blast furnace control method according to the present invention, the control output step transmits the control quantity command value input by the operator to the input / display terminal device when the operator inputs a transmission command using the operation quantity transmission button of the input / display terminal device after the execution of the prediction calculation in the second prediction step, or when a predetermined time has elapsed since the execution of the prediction calculation.

[0023] To solve the above-mentioned problems and achieve the objective, the method for producing molten iron according to the present invention includes the step of controlling a blast furnace in accordance with the guidance of the blast furnace control method described above and producing molten iron.

[0024] To solve the above-mentioned problems and achieve the objectives, the blast furnace operation method according to the present invention includes the step of controlling the blast furnace in accordance with the guidance provided by the blast furnace control method described above.

[0025] To solve the above-mentioned problems and achieve the objective, the blast furnace control device according to the present invention includes: a first prediction unit that uses a blast furnace physical model to predict the trend of one or more control variables among molten iron temperature, production rate, permeability index, and CO2 emission index when the current operating conditions are maintained; a second prediction unit that predicts the trend of one or more control variables among molten iron temperature, production rate, permeability index, and CO2 emission index when the operation is performed under arbitrary hypothetical operating conditions input by the operator; an output unit that displays the time-based mass balance and heat balance, including oxygen, carbon, and hydrogen in the blast furnace, when the trends of the control variables are predicted by the first and second prediction units, together with the control variables as a single graph on an input / display terminal device; and a control output unit that transmits the input operating conditions as manipulated variable command values.

[0026] In the blast furnace control device according to the present invention, the output unit displays the changes in the control variables predicted by the first prediction unit and the changes in the control variables predicted by the second prediction unit side by side with the graph.

[0027] The blast furnace control device according to the present invention includes, in the above invention, at least one of the operating conditions, the coke ratio at the top of the furnace, the blast flow rate, the pulverized coal flow rate, and the blast moisture content, and the output unit displays the changes in the operating conditions alongside the graph.

[0028] In the blast furnace control device according to the present invention, the mass balance includes the amount of reducing gas produced in the lower part of the furnace, the mass balance of carbon and oxygen, and the carbon balance derived from coke throughout the furnace.

[0029] To solve the above-mentioned problems and achieve the objective, the blast furnace operation simulation device according to the present invention comprises: a blast furnace physical model; a first prediction unit that uses the blast furnace physical model to offline predict the changes in one or more control variables among molten iron temperature, production rate, permeability index, and CO2 emission index when the current operating conditions are maintained; a second prediction unit that offline predicts the changes in one or more control variables among molten iron temperature, production rate, permeability index, and CO2 emission index when the operation is performed under arbitrary hypothetical operating conditions input by the operator; an output unit that displays the time-based mass balance and heat balance, including oxygen, carbon, and hydrogen in the blast furnace, when the changes in the control variables are predicted by the first and second prediction units, as a single graph on an input / display terminal device in association with the control variables; and a control output unit that transmits the input operating conditions as manipulated variable command values.

[0030] To solve the above-mentioned problems and achieve the objective, the input / display terminal device according to the present invention is an input / display terminal device that constitutes a blast furnace control system together with a blast furnace control device, and includes an I / F unit that displays an input interface for an operating variable indicating operating conditions that can be input by an operator, an operating amount of the operating variable, and an execution condition for predicting the transition of a control variable, and outputs the operating amount of the operating variable and the execution condition input by the operator to the blast furnace control device, a display output unit that displays information input from the blast furnace control device, and a unit that converts the input operating conditions into an operating amount command value. The system includes a control output unit that transmits the information, and the information includes a graph that, along with the control variables, shows the changes in one or more control variables from among molten iron temperature, production rate, permeability index, and CO2 emission index when the current operating conditions are maintained, and the changes in one or more control variables from among molten iron temperature, production rate, permeability index, and CO2 emission index when the system is operated under any hypothetical operating conditions input by the operator, and the material balance and heat balance per unit time including oxygen, carbon, and hydrogen in the blast furnace when these changes are predicted.

[0031] To solve the above-mentioned problems and achieve the objective, the blast furnace control system according to the present invention comprises the above-described blast furnace control device and the above-described input / display terminal device. [Effects of the Invention]

[0032] According to the blast furnace control method, molten iron manufacturing method, blast furnace operation method, blast furnace control device, blast furnace operation simulation device, input / display terminal device, and blast furnace control system of the present invention, operators can derive the optimal actions to achieve blast furnace operation with low CO2 emissions and low operating costs, taking into account the conditions inside the furnace. [Brief explanation of the drawing]

[0033] [Figure 1] Figure 1 shows the main operational and controllable variables in blast furnace operation. [Figure 2] Figure 2 shows the direction of change for each control variable when each operational variable is increased during blast furnace operation. [Figure 3] Figure 3 is a block diagram showing the overall configuration of a blast furnace control system including a blast furnace control device according to an embodiment of the present invention. [Figure 4] Figure 4 shows an example of information to be displayed on the I / F section of an input / display terminal device according to an embodiment of the present invention. [Figure 5] Figure 5 shows an example of information that a blast furnace control device according to an embodiment of the present invention displays on an input / display terminal device. [Figure 6] Figure 6 shows the relationship between the input and output of the blast furnace physical model used in the blast furnace control device according to an embodiment of the present invention. [Figure 7] Figure 7 shows the chemical reactions within the blast furnace physical model. [Figure 8] Figure 8 is a graph showing the mechanism of reducing gas generation in the lower part of the reactor. [Figure 9] Figure 9 is a graph showing the carbon balance derived from coke throughout the entire furnace. [Figure 10] Figure 10 is a graph illustrating the mechanism for determining production speed. [Figure 11] Figure 11 is a graph showing the mechanism for determining carbon intensity. [Figure 12] Figure 12 is a graph illustrating the mechanism for determining pressure loss. [Figure 13] Figure 13 is a graph showing the heat balance per unit time of a blast furnace. [Figure 14] Figure 14 is a graph showing the heat balance per unit weight (1 ton) of iron in a blast furnace. [Figure 15] Figure 15 is a graph integrating the mass balance and heat balance of a blast furnace. [Figure 16] Figure 16 is a graph showing an example of a what-if analysis when the airflow rate is increased. [Figure 17] Figure 17 is a graph showing an example of a what-if analysis when the coke ratio is reduced. [Figure 18] Figure 18 is a block diagram showing the overall configuration of a blast furnace operation simulation system, including a blast furnace operation simulation device according to an embodiment of the present invention. [Figure 19] Figure 19 shows the effects of conducting a blast furnace operation test using a blast furnace operation simulation device according to an embodiment of the present invention. [Modes for carrying out the invention]

[0034] A blast furnace control method, a method for manufacturing molten iron, a blast furnace operation method, a blast furnace control device, a blast furnace operation simulation device, an input / display terminal device, and a blast furnace control system according to embodiments of the present invention will be described with reference to the drawings.

[0035] (Blast furnace control system) The configuration of the blast furnace control system, including the blast furnace control device according to the embodiment, will be described with reference to Figure 1.

[0036] The blast furnace control system 1 is connected to the process computer 2 via a network N. The process computer 2 is connected to the blast furnace 3. Network N is, for example, a communication network such as a LAN (Local Area Network) or a public communication network such as the Internet. The blast furnace control system 1 includes a blast furnace control device 11 and an input / display terminal device 12.

[0037] (Blast furnace control system) The blast furnace control device 11 is specifically composed of a personal computer or workstation. The blast furnace control device 11 includes an input unit 111, a first prediction unit 112, a second prediction unit 113, a balance calculation unit 114, a display image generation unit 115, and an output unit 116.

[0038] The input unit 111 acquires various information necessary for controlling the blast furnace 3 from the process computer 2. Alternatively, various information necessary for controlling the blast furnace 3 is input to the input unit 111. The input unit 111 also acquires the manipulated values ​​of the control variables (operating conditions) input by the operator via the I / F unit 121 from the input / display terminal device 12.

[0039] The first prediction unit 112 uses a blast furnace physical model to predict the trends of one or more control variables, such as molten iron temperature, production rate, permeability index, and CO2 emission index, assuming the current operating conditions (operating variables) are maintained. The "operating conditions" include, for example, at least one of the following: coke ratio at the top of the furnace, blast flow rate, pulverized coal flow rate, and blast moisture content. The "permeability index" includes, for example, pressure loss. Furthermore, the "permeability index" may include the resistance of the gas flow inside the furnace, obtained by dividing the pressure loss by the gas flow rate at the top of the furnace. The "CO2 emission index" may include, for example, CO2 emissions, as well as the carbon intensity, obtained by dividing the amount of carbon supplied to the blast furnace or the amount of carbon consumed per unit time by the production rate. Details of the blast furnace physical model used by the first prediction unit 112 will be described later (see Figure 6).

[0040] The second prediction unit 113 predicts the trends of one or more control variables, such as molten iron temperature, production rate, permeability index, and CO2 emission index, when the machine is operated under any hypothetical operating conditions input by the operator. This processing by the second prediction unit 113 can be repeated by changing the manipulated variables, and after this prediction calculation is performed, processing by the output unit 116 is carried out.

[0041] The balance calculation unit 114 calculates the hourly mass balance and heat balance for oxygen, carbon, and hydrogen in the blast furnace at the current time. The balance calculation unit 114 also calculates the hourly mass balance and heat balance for oxygen, carbon, and hydrogen in the blast furnace when the first prediction unit 112 predicts the changes in the control variables, that is, when the current operating conditions are maintained. Furthermore, the balance calculation unit 114 calculates the hourly mass balance and heat balance for oxygen, carbon, and hydrogen in the blast furnace when the furnace is operated under arbitrary hypothetical operating conditions input by the operator, when the second prediction unit 113 predicts the changes in the control variables. The above "mass balance" includes, for example, the amount of reducing gas produced in the lower part of the furnace, the mass balance of carbon and oxygen, and the carbon balance derived from coke throughout the furnace.

[0042] Furthermore, the balance calculation unit 114 may, if necessary, calculate the carbon intensity for each by dividing the amount of carbon supplied from coke and the amount of carbon supplied from pulverized coal included in the material balance by the production rate.

[0043] The display image generation unit 115 generates an image (see Figure 5A) that associates the material balance and heat balance calculated by the balance calculation unit 114 with the control variables into a single graph. Specifically, this image shows the material balance and the heat balance, converted to per unit weight of iron using the production rate, side by side on a single graph.

[0044] Furthermore, the display image generation unit 115 generates images showing the changes in the control variables predicted by the first prediction unit 112 (see Figure 5B), images showing the changes in the control variables predicted by the second prediction unit 113 (see Figure 5B), and images showing the changes in the operating conditions (operational variables) (see Figure 5C).

[0045] Furthermore, the display image generation unit 115 may, if necessary, generate an image relating to the relationship between the carbon intensity derived from coke and the carbon intensity derived from pulverized coal (see line segments CD and CF in Figure 11). Also, the display image generation unit 115 may, if necessary, generate an image relating to a first line segment showing nitrogen contained in the blown air as a mass balance (see line segment IJ in Figure 12) and a second line segment showing the flow rate of the furnace top gas (line segment KM in Figure 12).

[0046] Furthermore, the display image generation unit 115 may, if necessary, generate an image relating to a third line segment (see line segment KN in Figure 12) that shows the pressure loss inside the furnace, which is an air permeability index, and is perpendicular to the second line segment. Also, the display image generation unit 115 may, if necessary, generate an image relating to the slope of a fourth line segment (see slope tanΦ of line segment KP in Figure 12) that shows the resistance of the gas flow inside the furnace, obtained by dividing the flow velocity of the top gas of the furnace by the pressure loss. The slope of the fourth line segment that shows the resistance of the gas flow inside the furnace is also shown as one of the air permeability indices.

[0047] The output unit 116 outputs various images generated by the display image generation unit 115 to the input / display terminal device 12, thereby displaying these images on the display output unit 122.

[0048] Specifically, the output unit 16 displays the time-based mass balance and heat balance for oxygen, carbon, and hydrogen in the blast furnace, as predicted by the first prediction unit 112 and the second prediction unit 113, together with the control variables, as a single graph (see Figure 5A). The output unit 16 also displays the changes in the control variables predicted by the first prediction unit 112 and the changes in the control variables predicted by the second prediction unit 113 alongside the above graph (see Figure 5B). Furthermore, the output unit 16 displays the changes in operating conditions (operational variables) alongside the above graph (see Figure 5C).

[0049] Furthermore, the output unit 16 may, if necessary, display the carbon intensity derived from coke and the carbon intensity derived from pulverized coal on the graph above, in relation to the carbon supply amount derived from coke, the carbon supply amount derived from pulverized coal, and the production rate (see line segments CD and CF in Figure 11). Also, the output unit 16 may, if necessary, display the slopes of the first, second, third, and fourth line segments on the graph above (see the slope tanΦ of line segments IJ, KM, KN and line segment KP in Figure 12).

[0050] In addition to outputting the image shown above, the output unit 16 also outputs the manipulated values ​​of the manipulated variables (operating conditions) acquired from the input / display terminal device 12 to the process computer 2 via the network N.

[0051] Furthermore, the output unit 16 also performs a process (control output step) to transmit the operating conditions input by the operator via the input / display terminal device 12 as manipulated variable command values. In this process, the manipulated variable command values ​​input by the operator to the input / display terminal device 12 are transmitted in the following cases: (1) When the operator inputs a transmission command using the operation variable transmission button on the input / display terminal device 12 after the second prediction unit 113 has performed the prediction calculation: (2) When a predetermined time has elapsed since the second prediction unit 113 performed the prediction calculation.

[0052] (Input / Display Terminal Device) The input / display terminal device 30 specifically consists of a personal computer or workstation having a display. The input / display terminal device 30 includes an I / F (interface) unit 121 and a display output unit 122.

[0053] The I / F unit 121 receives input of the manipulated amount of the control variable from the operator and outputs the received manipulated amount to the blast furnace control device 11. As shown in Figure 4, for example, the I / F unit 121 displays an input interface for the control variable that the operator can input, the manipulated amount of the control variable, and the execution conditions for the prediction calculation when predicting the changes in the control variable.

[0054] The I / F unit 121, as the "Operational Variable Input Unit" in Figure 4(a), displays the airflow rate, coke ratio, pulverized coal flow rate, and airflow moisture content as operational variables, and also displays input boxes for the operational variables of each operational variable. Furthermore, the I / F unit 121, as the "Execution Condition Input and Execution SW" in Figure 4(b), displays an item for inputting the future prediction time, which specifies which point in the future the prediction should be made for, and a prediction calculation execution button for executing the prediction calculation. In addition, the I / F unit 121, as the "Execution Condition Input and Execution SW" in Figure 4(b), also displays an operational variable transmission button for transmitting the operational variables entered in Figure 4(a).

[0055] When the operator presses the control variable transmission button, the I / F unit 121 outputs the control variable input by the operator to the blast furnace control device 11. Furthermore, when the operator presses the prediction calculation execution button, the I / F unit 121 outputs the execution conditions for the prediction calculation to the blast furnace control device 11. The I / F unit 121 may also display, for example, as shown in Figures 5D and E, below the graphs displayed by the display output unit 122, an input interface for the control variable indicating the operating conditions that the operator can input, the control variable's control value, and the execution conditions for the prediction calculation when predicting the changes in the control variable.

[0056] The display output unit 122 displays information input from the blast furnace control device 11. The display output unit 122 displays at least the following information: (1) A single graph (see Figure 5A) showing the relationship between the time-based mass balance and heat balance for oxygen, carbon, and hydrogen in the blast furnace when the first prediction unit 112 predicts the changes in the control variables. (2) A single graph (see Figure 5A) showing the relationship between the time-based mass balance and heat balance for oxygen, carbon, and hydrogen in the blast furnace when the second prediction unit 113 predicts the changes in the control variables. (3) Changes in the control variables predicted by the first prediction unit 112 (see Figure 5B) (4) Changes in the control variables predicted by the second prediction unit 113 (see Figure 5B) (5) Changes in operating conditions (operating variables) (see C in Figure 5)

[0057] In addition to the display function described above, the display output unit 122 also has an output function that outputs the manipulated amount of the confirmed manipulated variable to the process computer 2 via the blast furnace control device 11.

[0058] (Blast furnace physical model) The blast furnace physical model used in the blast furnace control device according to this embodiment consists of a set of partial differential equations that take into account multiple physical phenomena such as the reduction of iron ore, heat exchange between iron ore and coke, and the melting of iron ore, as described in Reference 1 below. This blast furnace physical model is a physical model (unsteady-state model) that can calculate variables (output variables) that indicate the state inside the blast furnace in an unsteady state.

[0059] Reference 1: Michiharu Hatano et al.: "Study of blast furnace firing operation using a non-steady-state model", Iron and Steel, vol. 68, p. 2369.

[0060] As shown in Figure 6, the main time-varying input variables (also called blast furnace operating variables or operational factors) within the boundary conditions given to this blast furnace physical model are as follows: (1) Coke ratio CR (kg / t) at the top of the furnace: Amount of coke added per ton of molten iron (2) Air flow rate (BV) [Nm 3 [ / min]: Flow rate of air supplied to the blast furnace (3) BVO flow rate [Nm³] 3 [ / min]: Flow rate of enriched oxygen injected into the blast furnace (4) Air supply temperature (BT) [°C]: Temperature of the air and enriched oxygen supplied to the blast furnace (5) Pulverized coal flow rate (pulverized coal injection rate, PCI) [kg / min]: Weight of pulverized coal used per ton of molten iron produced (6) Blast moisture (BM) [g / Nm 3 ]: Humidity of the air supplied to the blast furnace (7) Top pressure (TP) [kPa]: Pressure at the top of the furnace

[0061] Furthermore, the main output variables (control variables for the blast furnace) output from the blast furnace physical model are as follows: (1) Gas utilization rate in the furnace (ηCO): CO2 / (CO+CO2) (2) Solution loss carbon amount (sol loss carbon amount) (3) Production speed (pig production speed, Prod) (4) Hot metal temperature (HMT) (5) Heat loss from the furnace wall: The amount of heat absorbed by the cooling water when the furnace body is cooled by the cooling water. (6) Pressure loss (ΔP) (7)CO2 emissions (CO2)

[0062] In this invention, the time step (time interval) used to calculate the output variable is set to 30 minutes. However, the time step is variable depending on the purpose and is not limited to the value of this embodiment.

[0063] The blast furnace physical model considers 13 types of chemical reactions, as shown in Figure 7. In this embodiment, this blast furnace physical model is represented by a nonlinear state-space model, for example, as shown in equations (1) and (2) below.

[0064]

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[0065] In the above formulas (1) and (2), x(t) is a state variable calculated within the blast furnace physical model (including the temperatures of coke, iron, and gas, the degree of oxidation of iron ore, and the hot metal composition). u(t) is an input variable of the blast furnace physical model. For example, "u(t) = (BV(t), BVO(t), PCI(t), BM(t), BT(t), CR(t)) T " is represented by

[0066] Also, in the above formula (2), y(t) is the hot metal temperature, production rate, pressure loss, and CO2 emissions per ton of hot metal, which are control variables. For example, "y(t) = (y1(t), y2(t), y3(t), y4(t)) T " is represented by. Also, y(t) is calculated by the function C as shown in the above formula (2).

[0067] (Calculation of material balance) In the material balance calculation step performed by the material balance calculation unit 114, the heat balance and material balance (thermal material balance) inside the blast furnace process are calculated using such a blast furnace physical model. First, the generation mechanism of reducing gas (i.e., CO and H2 gases) in the lower part of the furnace (raceway and hearth) will be described.

[0068] The oxygen blown into the raceway is composed of the oxygen content in the pulverized coal, the moisture in the blast, and the blast air (including enriched oxygen). Here, let the respective input rates (kmol / s) at time step t be V O in,1 (t), V O in,2 (t), V O in,3 (t).

[0069] In this case, the oxygen input rate V O in,1 (t) in the pulverized coal is represented by the following formula (3). Also, the oxygen input rate V O in,2 (t) due to the moisture in the blast is represented by the following formula (4). Also, the oxygen input rate V O in,3 (t) due to the air in the blast is represented by the following formula (5).

[0070]

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number

[0071] In equations (3) to (5) above, BV(t) is the airflow rate, BVO(t) is the enriched oxygen flow rate, PCI(t) is the pulverized coal flow rate, and X O PC This is the weight fraction (weight percentage) of oxygen in pulverized coal, M O is the atomic weight of oxygen, and BM(t) is the moisture content of the airflow.

[0072] All oxygen blown into the raceway reacts with carbon derived from coke or pulverized coal, converting it into CO gas. Furthermore, the reaction between carbon and oxygen in the raceway is shown in Figure 7, R i (i=10,11,12,13). Here, at time step t, the carbon consumption rate in pulverized coal is V. C out,1 (t) The rate of carbon consumption in coke due to moisture during airflow is V C out,2 (t) The carbon consumption rate in coke is V C out,3 Let (t) be the case.

[0073] In the reactions between carbon and oxygen in the raceway, the molar ratio of carbon to oxygen is 1:1 in all reactions, and as shown in equation (6) below, the rate of oxygen input in the raceway is equal to the rate of carbon consumption.

[0074]

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[0075] In this embodiment, it is assumed that the pulverized coal blown into the tuyeres is completely burned at the tip of the tuyeres. That is, the carbon consumption rate in the pulverized coal is uniquely determined by the input to the blast furnace physical model, as shown in equation (7) below.

[0076]

number

[0077] In equation (7) above, V PC in (t) is the blowing rate of pulverized coal (kg / min), X C PC This is the weight fraction of carbon in pulverized coal, M C V is the atomic weight of carbon. Also, the injection rate V of pulverized coal in equation (7) above. PC in (t) is expressed by the following equation (8).

[0078]

number

[0079] In equation (8) above, BV(t) is the airflow rate, BVO(t) is the oxygen-enriched flow rate, and PCI(t) is the pulverized coal flow rate. Assuming that moisture in the air reacts with coke, "V C out,2 (t) = V O in,2 (t)” Therefore, the relationship in equation (9) below is derived from equation (6) above.

[0080]

number

[0081] In the above equation (9), V O in,1 (t) is the oxygen input rate in pulverized coal, V O in,3 (t) is the oxygen input rate by the air being blown, V C out,1(t) is the carbon consumption rate in pulverized coal. Furthermore, since the right-hand side of equation (9) above is uniquely determined from the input variables, the combustion rate of coke in the raceway is uniquely determined by the input variables. Also, in the raceway, as shown in equations (10) and (11) below, the hydrogen in the water vapor and pulverized coal is converted into H2 gas.

[0082]

number

number

[0083] In the above equation (10), V H2 in,1 (t) is the rate at which hydrogen is introduced into the steam in the raceway, V H2 out,1 (t) is the rate of hydrogen production in water vapor in the raceway, BV(t) is the airflow rate, BVO(t) is the oxygen-enriched flow rate, and BM(t) is the air moisture content. Also, in the above equation (11), V H2 in,2 (t) is the rate at which hydrogen is injected into the pulverized coal in the raceway, V H2 out,2 (t) is the rate of hydrogen production in pulverized coal in the raceway. Also, in equation (11) above, BV(t) is the airflow rate, BVO(t) is the enriched oxygen flow rate, PCI(t) is the pulverized coal flow rate, X H PC This is the weight fraction of hydrogen in pulverized coal, M H This is the atomic weight of hydrogen.

[0084] At the interface between molten iron and slag in the hearth, as shown in equation (12) below, SiO2 in the slag reacts with carbon in the coke to produce CO gas. In this reaction as well, the molar ratio of oxygen to CO gas is 1:1.

[0085]

number

[0086] In the above equation (12), V O in,4 (t) is the oxygen input rate into the slag at the interface between the molten iron and the slag, V C out,4 (t) is the carbon consumption rate in coke at the interface between molten iron and slag.

[0087] Figure 8 shows the generation mechanism of reducing gases (CO gas, H2 gas) in the lower part of the reactor.

[0088] Next, we will consider the carbon balance in the coke throughout the furnace. Reaction R in Figure 7. i In addition to (i=7,10,11), reaction R occurs inside the reactor. i (i=2,3,5,8) consumes carbon in the coke. Of this, the portion due to the carburizing reaction is "V C out,6 (t=R8) and other reactions are defined as "V C out,5 Let (t) = R2 + R3 + R5. Also, let V be the rate of carbon supply from coke introduced from the top of the furnace (kmol / s). c in Let (t) be the carbon supply rate V derived from coke that is fed in from the top of the furnace. c in (t) can be expressed as shown in equation (13) below.

[0089]

number

[0090] In the above equation (13), V Coke in (t) is the coke feeding rate from the top of the furnace (kg / min), X C Coke M is the weight fraction of carbon in coke. C is the atomic weight of carbon. In a steady state, the carbon consumption rate and the carbon supply rate are equal, as shown in equation (14) below.

[0091]

number

[0092] However, it should be noted that equation (14) above does not hold true in transient states, such as immediately after a change in the coke ratio. Figure 9 shows a bar graph representing the supply rate and consumption rate of carbon derived from coke, that is, the overall carbon balance derived from coke in the furnace.

[0093] Next, we will explain the mechanism by which the production rate Prod(t) is determined by the coke input rate and the directly controllable coke ratio CR(t). When the production rate Prod(t) is the rate at which iron is input from the top of the furnace, the coke ratio CR(t) is defined by the following equation (15).

[0094]

number

[0095] In the above equation (15), V Coke in (t) is the coke feeding rate from the furnace top (kg / min), and Prod(t) is the production rate. As shown in equation (16) below, the molar feeding rate of iron in the iron ore (iron supply rate from iron ore fed from the furnace top) V Fe in (t) is proportional to the production rate Prod(t).

[0096]

number

[0097] In equation (16) above, Prod(t) is the production rate, M Fe V is the atomic weight of iron. V is the carbon supply rate from coke introduced from the top of the furnace. C in (t) and the rate of iron supply from iron ore V Fe in The relationship between (t) and (t) is given by equation (17) below, using equations (13), (15), and (16) above.

[0098] [Number]

[0099] In the above formula (17), X C Coke is the weight fraction of carbon in the coke, a is the proportionality constant, and V C in (t) is the carbon supply rate from the coke, and V Fe in (t) is the iron supply rate from the iron ore. Also, in the above formula (17), V Coke in (t) is the coke charging rate from the top of the furnace (kg / min), and Prod(t) is the production rate. The proportionality constant a can be obtained by "a = M C / M Fe × 1000". Here, M C is the atomic weight of carbon, and M Fe is the atomic weight of iron.

[0100] Figure 10 shows the relationship between such a coke charging rate and the production rate. In Figure 10, in order to present the means for operating the coke charging rate together, the carbon balance in the coke shown in Figure 9 is also shown (see F).

[0101] In Figure 10, let the length of line segment OA be V Fe in (t), and the length of line segment AB be V C in (t). Also, the slope of line segment OB is "tanθ = V C in (t) / V Fe in (t)". If the x-coordinate of point C is an arbitrary constant b, then "CR(t) × X C Coke ", which means the carbon unit from the coke, is proportional to the length of line segment CD.

[0102] From this, in order to increase the production rate, the coke charging rate (V Coke inIt can be seen that increasing (t) or decreasing the coke ratio CR(t) is effective. Although the coke feeding rate cannot be directly manipulated, for example, increasing the flow rate of oxygen supplied to the raceway can increase the coke combustion rate (carbon consumption rate in coke) V C out,3 By increasing (t), the coke feeding rate can be increased.

[0103] The carbon intensity is the total amount of carbon (kg) in coke and pulverized coal per unit weight (1 ton) of iron. C tot (t) is defined by the following equation (18).

[0104]

number

[0105] In equation (18) above, CR(t) is the coke ratio, X C Coke X is the weight fraction of carbon in coke. C PC is the weight fraction of carbon in pulverized coal. Furthermore, PCR(t) in the above formula (18) is the amount of pulverized coal per unit weight (1 ton) of iron (kg-PC / t-Fe), and is expressed in the following formula (19).

[0106]

number

[0107] In the above equation (19), V PC in (t) is the injection rate of pulverized coal, and Prod(t) is the production rate. The first term of the above formula (18) is the carbon intensity derived from coke, "CR(t) × X C Coke The carbon intensity derived from pulverized coal in the second term of the above formula (18), "PCR(t)×X C PCIt is important to note that this is the result of operations. Using the proportionality constant a in equation (17) above, equation (20) can be derived from equations (7) and (16) above.

[0108]

number

[0109] In the above formula (20), PCR(t) is the amount of pulverized coal, X C PC is the weight fraction of carbon in pulverized coal, a is the proportionality constant, V C out,1 (t) is the carbon consumption rate in pulverized coal, V Fe in (t) is the rate of iron supply from iron ore. Substituting equation (17) into the first term on the right-hand side of equation (18) and equation (18) into the second term on the right-hand side of equation (18), we derive equation (21) below.

[0110]

number

[0111] In equation (21) above, a is the proportionality constant, V C in (t) is the carbon supply rate from coke, V C out,1 (t) is the carbon consumption rate in pulverized coal, V Fe in (t) is the rate of iron supply from iron ore. According to the relationship in equation (21) above, V C out,1 (t) and V Fe in By taking the ratio with (t), it becomes possible to quantify the carbon intensity derived from pulverized coal and the carbon intensity derived from coke using the same scale.

[0112] Figure 11 shows the mechanism for determining carbon intensity. Figure 11 is a combination of Figure 10 and Figure 8, which shows the mass balance at the bottom of the furnace. In Figure 11, in order to ensure consistency with Figure 10, the carbon consumption rate in coke at the bottom of the furnace is expressed as "Σ 4 k=2 V C out,k Figure 8 is repositioned and drawn so that (t) lies in the region where y>0.

[0113] In Figure 11, the length of line segment AE is equal to the carbon consumption rate V in pulverized coal. C out,1 This corresponds to (t). Also, in Figure 11, the slope of line segment OE is given by "tanφ = -V C out,1 (t) / V Fe in (t) is the length of the line segment CF, and the carbon intensity derived from pulverized coal is "PCR(t) × X C PC It is proportional to the carbon intensity I shown in equation (18) above. Therefore, the line segment DF is proportional to the carbon intensity I C tot This corresponds to (t).

[0114] By displaying the carbon intensity, which is a relationship between production rate and the amount of carbon supplied per unit time from coke and pulverized coal, it becomes possible to understand the relationship between changes in operating conditions and changes in carbon intensity, which is an indicator of CO2 emissions.

[0115] Next, we will consider the mechanism for determining the pressure loss inside the furnace (hereinafter also referred to as "pressure loss"). The pressure loss is determined by the gas flow rate V at the top of the furnace. top (t) is approximately proportional. The furnace top gas consists of N2, CO, CO2, H2, and H2O. Water vapor originating from the moisture content of the raw materials is generated near the furnace top and has little effect on pressure drop, so it is not considered here.

[0116] Of the top gas in the furnace, the nitrogen comes entirely from the N2 gas in the hot air blown into the tuyeres. The other gas components are CO and H2 gases generated in the lower part of the furnace, and the reaction R shown in Figure 7. iThe CO gas produced by (i=2,3,5) is partially oxidized by reaction (i=1,4). Note that the molar flow rate of the gas does not change due to these reactions, and the molar flow rate of the top gas is V. top (t) can be expressed as shown in equation (22) below.

[0117]

number

[0118] In the above equation (22), V N2 in (t) is the molar flow rate of nitrogen blown into the furnace. This molar flow rate of nitrogen V N2 in (t) is "V N2 in (t) can be calculated using the formula "(t) = BV(t) × 0.79", where BV(t) is the airflow rate.

[0119] Figure 12 shows the mechanism for determining pressure loss, and is the same as Figure 11 but with the addition of elements related to the determination of the furnace pressure. First, if we add a line segment IJ (first line segment) representing the nitrogen content in the blown air to the mass balance section at the bottom of the furnace, the flow rate of the top gas becomes equal to the length of the line segment KM (second line segment).

[0120] Furthermore, if the pressure loss ΔP(t) inside the furnace is the length of the line segment KN (third line segment) perpendicular to the line segment KM, then the slope of the line segment KP (fourth line segment) is given by "tanΦ = V top The expression "(t) / ΔP(t)" represents the resistance of the gas flow inside the furnace and also serves as an indicator of permeability. This resistance to the gas flow inside the furnace is calculated, for example, based on the Ergun formula, but is greatly affected by the coke ratio. That is, the slopes of line segment OD and line segment KP move similarly when the coke ratio is changed.

[0121] (Calculation of heat balance) Next, we will consider the heat balance of the blast furnace. Figure 13 shows the heat balance of the blast furnace per unit time. The heat input consists of the heat of combustion of carbon in coke and pulverized coal in the raceway, the heat generated by the CO gas reduction reaction R1, and the sensible heat from the blown air. These heat inputs are divided into V E in,k Let (t)(k=1,2,3). Also, the heat output is the sensible heat of molten iron and slag, and the reaction R in Figure 7. i The heat output consists of heat absorption due to (i=2,3,5), heat of decomposition of moisture in the blown air, heat absorption due to hydrogen gas reduction R4, heat loss from the furnace wall, and other heat (water vapor reaction, sensible heat of the top gas, heat of carburizing reaction). These heat outputs are each V E out,k Let (t)(k=1,2,…,6).

[0122] Next, in order to convert the heat per unit time to the heat per unit of molten iron, the heat balance per unit time shown in Figure 13 is standardized using the melting rate of iron. Figure 14 shows the heat balance per unit of iron in the blast furnace. As shown in Figure 14, by expressing the heat balance as an amount per unit of iron, it becomes possible to correlate it with the reducing agent ratio.

[0123] First, the length of line segment QR is defined as the rate of iron dissolution, which can be practically correlated with the production rate. Then, line segment SR is defined as the energy input rate Σ. 3 k=1 V E in,k (t), line segment TR V E out,1 Let (t). Then the slope of the line segment QS is given by "tanξ = Σ 3 k=1 V E in,k (t) / V Fe in (t) The slope of the line segment QT is "tanη = V E out,1 (t) / V Fe in (t)

[0124] tanη represents the sensible heat of molten iron and slag per unit weight (1 ton) of iron, and is approximately proportional to the molten iron temperature. Here, in order to ensure consistency with Figure 9, the length of the line segment WX is given by "a × V" using the proportionality constant a defined in equation (17) above. E out,1 (t) / V Fe in (t)

[0125] Figure 15 shows a graph of the heat and mass balance, which integrates the mass balance shown in Figure 12 and the heat balance shown in Figure 14. The following explanation of the heat and mass balance when operational actions are carried out will be based on this figure.

[0126] Figure 16 shows the control variables, specifically the airflow rate BV set to 200 Nm³. 3 This shows an example of a what-if analysis when the flow rate is increased by only / min. In Figure 16, (a) shows the operational variables (operating conditions), (b) shows the heat and mass balance, and (c) shows the control variables. The operational variables are the airflow rate BV, coke ratio CR, pulverized coal flow rate PCI, and airflow moisture BM. The control variables are the carbon intensity, production rate Prod, molten iron temperature HMT, and pressure loss ΔP. ​​Note that in Figure 16, carbon intensity is used as the control variable instead of CO2 emissions, and the increase or decrease in CO2 emissions is judged according to the increase or decrease in carbon intensity. However, CO2 emissions themselves can also be used as the control variable. It is also possible to determine CO2 emissions from carbon intensity.

[0127] In Figures 16(a) and (c), the origin of time is the present time. Also, in Figure 16(a), the change in the control variables when the current operating conditions (control variables) are maintained is shown by a dashed line, and a hypothetical operating condition is implemented (airflow rate BV set to 200 Nm³). 3 The changes in the control variables when the rate increases by 200 Nm³ are shown by a dashed line. In Figure 16(c), the changes in the control variables when the current operating conditions (control variables) are maintained are shown by a dashed line, and a hypothetical operating condition is implemented (airflow rate BV set to 200 Nm³). 3 The changes in the control variable when it increases by a minimum of 1 / min are illustrated by a dashed line.

[0128] Furthermore, in Figure 16(b), the current state and hypothetical operating conditions are implemented for each element of the mass balance and heat balance in Figure 15 (with the airflow rate BV set to 200 Nm³). 3 The state after 10 hours if the rate increases by a minimum of 10 minutes is also shown.

[0129] In Figure 16, as the airflow rate BV increases, the oxygen and nitrogen flow rates in the airflow also increase. Although the coke input rate increases due to the increase in oxygen flow rate, the coke ratio CR remains constant, so the production rate Prod increases in proportion to the coke input rate. In addition, since the furnace gas increases almost in proportion to the airflow rate, the pressure loss ΔP in the furnace also increases. Furthermore, since the coke ratio CR and the pulverized coal ratio (pulverized coal flow rate PCI per ton of molten iron) remain constant, the carbon intensity does not change.

[0130] Regarding the heat balance, although the amount of heat input per unit time and the amount of heat consumed due to the discharge of sensible heat from molten iron and slag increase in proportion to the airflow rate, the heat balance per unit of iron remains almost constant after being normalized by the production rate. As a result, the molten iron temperature (HMT) has also remained almost unchanged.

[0131] Figure 17 shows an example of a what-if analysis when the coke ratio CR, one of the instrumental variables, is reduced by 20 kg / t. In Figure 17, (a) shows the instrumental variable (operating conditions), (b) shows the heat and mass balance, and (c) shows the control variable. The types of instrumental and control variables are the same as in Figure 16.

[0132] In Figures 17(a) and (c), the origin of time is the present time. In Figure 17(a), the changes in the instrumental variables when the current operating conditions (instrumental variables) are maintained are shown by a dashed line, and the changes in the instrumental variables when hypothetical operating conditions are implemented (coke ratio CR reduced by 20 kg / t) are shown by a dashed line. In Figure 17(c), the changes in the control variables when the current operating conditions (instrumental variables) are maintained are shown by a dashed line, and the changes in the control variables when hypothetical operating conditions are implemented (coke ratio CR reduced by 20 kg / t) are shown by a dashed line.

[0133] Furthermore, Figure 17(b) shows both the current state and the state 10 hours later when hypothetical operating conditions are implemented (coke ratio CR reduced by 20 kg / t) for each element of the mass balance and heat balance in Figure 15.

[0134] In Figure 17, since the airflow rate BV is constant, there is almost no change in the mass balance at the bottom of the furnace. However, as a result of lowering the coke ratio CR, the coke input rate decreases, while the iron input rate (production rate Prod) increases. In addition, the carbon intensity decreases not only due to the decrease in the coke ratio CR, but also due to the decrease in the pulverized coal ratio obtained as a result of operation. Furthermore, although the gas flow rate inside the furnace remains almost unchanged, the pressure loss ΔP inside the furnace increases because the resistance to gas flow increases due to the decrease in the coke ratio CR.

[0135] Regarding the heat balance, although there is little change in the heat balance per unit time due to the increase in the production rate (Prod), the molten iron temperature (HMT) decreases because the amount of heat input per unit of iron and the sensible heat of molten iron and slag, after being standardized per unit of iron, have decreased.

[0136] Figures 16 and 17 illustrate examples where the airflow rate BV and coke ratio CR are manipulated, but the same applies when other controllable variables are manipulated.

[0137] (Blast furnace operation simulation device) The blast furnace control device 11, as described in Figure 3, was implemented as a control system in an actual blast furnace 3 by combining it with a real-time control system, but it can also be used as an offline blast furnace operation simulation device.

[0138] As shown in Figure 18, the blast furnace operation simulation system 1A according to this embodiment comprises a blast furnace operation simulation device 11A and an input / display terminal device 12. The blast furnace operation simulation device 11A also comprises an input unit 111, a first prediction unit 112, a second prediction unit 113, a balance calculation unit 114, a display image generation unit 115, an output unit 116, and a blast furnace physical model 117.

[0139] Instead of being connected to an actual process computer 2 or similar device, the blast furnace operation simulation device 11A has an internal blast furnace physical model 117 that reproduces the phenomena of a blast furnace. By outputting manipulated variables, for example, the results of guidance calculations, to the blast furnace physical model 117, the blast furnace physical model 117 simulates the phenomena of a blast furnace in real time.

[0140] Using the blast furnace operation simulation device 11A shown in Figure 18, a blast furnace operation test was conducted with the aim of achieving low carbon emissions and low operating costs by reducing the coke ratio CR while satisfying predetermined molten iron temperature HMT and production rate Prod. The results shown in Figure 19 were obtained. In this blast furnace operation test, the variability of control variables was investigated for 16 operators, both with and without guidance from the blast furnace operation simulation device 11A.

[0141] Figure 19(a) shows the average value of carbon intensity, with the left side of the graph showing the value without guidance and the right side showing the value with guidance. Figure 19(b) shows the variation in molten iron temperature HMT, with the left side of the graph showing the value without guidance and the right side showing the value with guidance. Figure 19(c) shows the time exceeding the upper limit of pressure drop ΔP, with the left side of the graph showing the value without guidance and the right side showing the value with guidance.

[0142] As shown in Figure 19, the average value of carbon intensity, the variation in molten iron temperature (HMT), and the time exceeding the upper limit of pressure drop (ΔP) all show smaller variations with guidance compared to the case without guidance. Therefore, it can be seen that this method makes it possible to achieve low CO2 emissions and stable blast furnace operation.

[0143] (Blast furnace control method) A blast furnace control method according to an embodiment will now be described. The blast furnace control method consists of a first prediction step performed by a first prediction unit 112, a second prediction step performed by a second prediction unit 113, a balance calculation step performed by a balance calculation unit 114, a display image generation step performed by a display image generation unit 115, and a display step performed by an output unit 116. In addition, the blast furnace control method performs a control output step performed by the output unit 116 after the display step. The second prediction step can be repeated by changing the manipulated variable, and the display step is performed after the second prediction step. Details of each step have already been explained along with the configuration of the blast furnace control device 11 described above, so they will not be explained here.

[0144] (Method of producing molten iron) The blast furnace control method according to this embodiment can also be applied to a method for manufacturing molten iron. In this case, in addition to the first prediction step, second prediction step, balance calculation step, display image generation step, and display step in the blast furnace control method described above, a step of controlling the blast furnace and manufacturing molten iron according to the guidance from the display step is performed.

[0145] (Blast furnace operation methods) The blast furnace control method according to this embodiment can also be applied to the operation method of a blast furnace. In this case, in addition to the first prediction step, second prediction step, balance calculation step, display image generation step, and display step in the blast furnace control method described above, a step of controlling the blast furnace according to the guidance from the display step is performed.

[0146] As described above, the blast furnace control method, molten iron manufacturing method, blast furnace operation method, blast furnace control device, blast furnace operation simulation device, input / display terminal device, and blast furnace control system according to this embodiment enable the operator to derive the optimal action to achieve low CO2 and low operating costs in blast furnace operation, taking into account the conditions inside the furnace. Specifically, the oxygen balance in the raceway, the coke balance and heat balance of the entire furnace, calculated within the blast furnace physical model, are displayed side by side, showing the current state and the future state when the operator virtually performs the operation action on the interface. This allows the operator to quantitatively grasp the effect of their operation action and derive appropriate operation action themselves.

[0147] Furthermore, in the blast furnace control method, molten iron manufacturing method, blast furnace operation method, blast furnace control device, blast furnace operation simulation device, input / display terminal device, and blast furnace control system according to this embodiment, the future predicted trends of changes in control variables when the operational variables are changed are presented along with changes in the heat and mass balance, thereby deepening the understanding of the mechanism and enabling the operator to take operational actions to realize low-carbon and stable blast furnace operation.

[0148] The blast furnace control method, molten iron manufacturing method, blast furnace operation method, blast furnace control device, blast furnace operation simulation device, input / display terminal device, and blast furnace control system according to the present invention have been specifically described above with reference to embodiments and examples for carrying out the invention. However, the spirit of the present invention is not limited to these descriptions and must be interpreted broadly based on the claims. Furthermore, it goes without saying that various modifications and alterations based on these descriptions are also included in the spirit of the present invention. [Explanation of Symbols]

[0149] 1. Blast Furnace Control System 1A Blast Furnace Operation Simulation System 2 Process computers 3 blast furnace 11 Blast Furnace Control System 11A Blast Furnace Operation Simulation System 111 Input Section 112 First Prediction Section 113 Second Prediction Section 114 Income and Expenditure Calculation Department 115 Display Image Generation Unit 116 Output section 117 Blast Furnace Physical Models 12 Input and display terminal devices 121 I / F section 122 Display Output Section N Network

Claims

1. The computer's first prediction unit uses a blast furnace physical model to predict the molten iron temperature, production rate, permeability index, and CO2 level assuming current operating conditions are maintained. ２ A first prediction step involves predicting the trend of one or more control variables among the occurrence indicators, The second prediction unit of the aforementioned computer predicts the molten iron temperature, production rate, permeability index, and CO2 when operating under any hypothetical operating conditions input by the operator. ２ A second prediction step predicts the trend of one or more control variables among the occurrence indicators, The output unit of the computer predicts the changes in the control variables in the first prediction step and the second prediction step, and displays the time-based mass balance and heat balance, including oxygen, carbon, and hydrogen in the blast furnace, together with the control variables as a single graph on an input / display terminal device. A control output step that transmits the input operating conditions as a manipulated variable command value, A blast furnace control method including the following.

2. The blast furnace control method according to claim 1, wherein the display step displays the changes in the control variables predicted in the first prediction step and the changes in the control variables predicted in the second prediction step side by side with the graph.

3. The aforementioned operating conditions include at least one of the following: coke ratio at the top of the furnace, airflow rate, pulverized coal flow rate, and air moisture content. The blast furnace control method according to claim 2, wherein the display step displays the changes in the operating conditions alongside the graph.

4. The blast furnace control method according to claim 1, wherein the mass balance includes the amount of reducing gas produced in the lower part of the furnace, the mass balance of carbon and oxygen, and the carbon balance derived from coke throughout the furnace.

5. The method further includes a balance calculation step in which the carbon intensity of each component is calculated by dividing the amount of carbon supplied from coke and the amount of carbon supplied from pulverized coal, which are included in the material balance, by the production rate. The display step involves displaying the carbon intensity derived from coke and the carbon intensity derived from pulverized coal on the graph in relation to the carbon supply amount derived from coke, the carbon supply amount derived from pulverized coal, and the production rate. The blast furnace control method according to claim 4.

6. The aforementioned display step is, The aforementioned mass balance includes the first line segment representing nitrogen contained in the blown air, The second line segment shows the flow rate of the top gas of the furnace, The aforementioned air permeability index represents the pressure loss inside the furnace, and the third line segment is perpendicular to the second line segment, The slope of the fourth line segment, which represents the resistance of the gas flow inside the furnace, obtained by dividing the velocity of the top gas by the pressure loss, The blast furnace control method according to claim 5, which displays the above on the graph.

7. The blast furnace control method according to claim 1, wherein the display step involves displaying the mass balance and the heat balance converted to a per-unit weight of iron using the production rate side by side on a single graph.

8. The blast furnace control method according to claim 1, wherein the second prediction step can be repeated by changing the manipulated amount, and the display step is performed after the second prediction step is performed.

9. The blast furnace control method according to claim 8, wherein the control output step transmits the control quantity command value input by the operator to the input / display terminal device after the execution of the prediction calculation in the second prediction step, when the operator inputs a transmission command using the control quantity transmission button of the input / display terminal device, or when a predetermined time has elapsed since the execution of the prediction calculation.

10. A method for producing molten iron, comprising the step of controlling a blast furnace in accordance with guidance from a blast furnace control method described in any one of claims 1 to 9, and producing molten iron.

11. A method for operating a blast furnace, comprising the step of controlling a blast furnace in accordance with guidance from a blast furnace control method according to any one of claims 1 to 9.

12. Using a blast furnace physical model, we can determine the molten iron temperature, production rate, permeability index, and CO2 levels under current operating conditions. ２ A first prediction unit predicts the trend of one or more control variables among the occurrence indicators, The molten iron temperature, production rate, permeability index, and CO2 when operating under any hypothetical operating conditions entered by the operator. ２ A second prediction unit predicts the trend of one or more control variables among the occurrence indicators, An output unit that displays the time-based mass balance and heat balance, including oxygen, carbon, and hydrogen in the blast furnace, as predicted by the first and second prediction units, together with the control variables, as a single graph on an input / display terminal device. A control output unit that transmits the input operating conditions as a manipulated variable command value, A blast furnace control device equipped with the following features.

13. The blast furnace control device according to claim 12, wherein the output unit displays the changes in the control variable predicted by the first prediction unit and the changes in the control variable predicted by the second prediction unit side by side with the graph.

14. The aforementioned operating conditions include at least one of the following: coke ratio at the top of the furnace, airflow rate, pulverized coal flow rate, and air moisture content. The blast furnace control device according to claim 13, wherein the output unit displays the changes in the operating conditions alongside the graph.

15. The blast furnace control device according to claim 12, wherein the mass balance includes the amount of reducing gas produced in the lower part of the furnace, the mass balance of carbon and oxygen, and the carbon balance derived from coke throughout the furnace.

16. Blast furnace physical model and, Using the blast furnace physical model described above, the molten iron temperature, production rate, permeability index, and CO2 levels are determined assuming the current operating conditions are maintained. ２ A first prediction unit that offline predicts the trend of one or more control variables among the occurrence indicators, The molten iron temperature, production rate, permeability index, and CO2 when operating under any hypothetical operating conditions entered by the operator. ２ A second prediction unit that offline predicts the trend of one or more control variables among the occurrence indicators, An output unit that displays the time-based mass balance and heat balance, including oxygen, carbon, and hydrogen in the blast furnace, as predicted by the first and second prediction units, together with the control variables, as a single graph on an input / display terminal device. A control output unit that transmits the input operating conditions as a manipulated variable command value, A blast furnace operation simulation device equipped with [specific features / features].

17. An input / display terminal device that, together with the blast furnace control device, constitutes the blast furnace control system, An I / F unit that displays an input interface for operating variables that can be input by the operator, the manipulated amounts of the operating variables, and the execution conditions for predicting the changes in the control variables, and outputs the manipulated amounts of the operating variables and the execution conditions input by the operator to the blast furnace control device, A display output unit that displays information input from the blast furnace control device, A control output unit that transmits the input operating conditions as a manipulated variable command value, Equipped with, The aforementioned information includes the molten iron temperature, production rate, permeability index, and CO2, which are predicted using a blast furnace physical model, assuming current operating conditions are maintained. ２ The changes in one or more control variables among the generation indicators, and the molten iron temperature, production rate, permeability index, and CO2 when operating under any hypothetical operating conditions input by the operator. ２ The changes in one or more control variables among the generation indicators, along with the predicted time-based mass balance and heat balance including oxygen, carbon, and hydrogen in the blast furnace, are shown in a single graph associated with the said control variables. Input and display terminal device.

18. A blast furnace control system comprising a blast furnace control device according to any one of claims 12 to 15 and an input / display terminal device according to claim 17.

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