Blast furnace malfunction prediction device, blast furnace malfunction prediction method, blast furnace operation method, and molten iron production method

Abstract

To provide a blast furnace malfunction prediction device, a blast furnace malfunction prediction method, a blast furnace operation method, and a molten iron manufacturing method that can predict deterioration of air permeability inside the furnace and abnormal areas in the circumferential direction of the furnace body in advance and in real time by combining deviations of pulverized coal in the circumferential direction of the furnace body and deviations of furnace body temperature in the circumferential direction of the furnace body. [Solution] The blast furnace operation abnormality prediction device includes: a blast furnace circumference deviation visualization unit that calculates the deviation of the pulverized coal flow rate and furnace body temperature in the circumferential direction of the furnace body using the pulverized coal flow rate at each tuyere of the pulverized coal blown into the blast furnace and the furnace body temperature at multiple positions in the circumferential direction of the blast furnace body; a permeability abnormality prediction unit that determines whether or not there are signs of a blast furnace permeability abnormality based on the deviation of the pulverized coal flow rate and furnace body temperature in the circumferential direction of the furnace body; and an abnormality prediction alarm unit that, if it is determined that there are signs of a permeability abnormality, identifies and provides guidance on the parts of the furnace body in the circumferential direction where there is a risk of a permeability abnormality occurring.

Description

Technical Field

[0001] The present invention relates to an operation abnormality prediction device for a blast furnace, an operation abnormality prediction method for a blast furnace, an operation method for a blast furnace, and a method for producing hot metal.

Background Art

[0002] In a blast furnace, a process is performed in which iron ore is charged from the upper part of the furnace as the main raw material and coke is charged as a subsidiary raw material, hot air and pulverized coal are blown from tuyeres at the lower part of the furnace, and molten iron is taken out from the taphole further below the tuyeres. Coke and pulverized coal burn at the tuyeres to become CO gas, which is used for reducing iron ore. Further, coke plays a very important role in ensuring the air permeability of the gas in the furnace.

[0003] The blast furnace operates 24 hours a day, 365 days a year, and since it takes a long time to restart when the operation stops due to a serious trouble, stable operation is required. However, in recent blast furnace operations, in order to reduce CO2 emissions and the cost of hot metal, reduction of the amount of coke used per ton of hot metal (coke ratio) has been demanded. Therefore, along with the reduction in the amount of coke used, which plays a role in ensuring air permeability, the gas flow in the furnace tends to become unstable, and a trouble called "blow-through", in which the gas in the furnace locally blows up, has frequently occurred.

[0004] As a cause of the destabilization of the gas flow, a deviation in the pulverized coal flow rate blown from the lower part of the furnace in the circumferential direction of the furnace body is known. For example, in Patent Document 1, it is disclosed that in a direction where the amount of pulverized coal blown in the circumferential direction of the furnace body is small, the heating time of the solid becomes long and the radiant heat amount becomes large in accordance with the long residence time, that is, the furnace body temperature becomes high. Therefore, in Patent Document 1, when a situation of thermal deficiency occurs in the upper part of the furnace and a tendency for deposits to form and grow on the inner wall of the furnace body is predicted, a technique for controlling the amount of pulverized coal blown from the tuyere based on the deviation amount in the circumferential direction of the furnace body of the furnace temperature is proposed.

[0005] Furthermore, Patent Document 1 proposes a method in which the amount of pulverized coal fuel injected is increased at tuyeres facing the direction of higher furnace body temperature, and conversely, decreased at tuyeres facing the direction of lower furnace body temperature. In Patent Document 1, by controlling the amount of pulverized coal injected as described above, a localized gas flow is generated around the deposits, thereby removing the deposits by reduction and melting.

[0006] Furthermore, Patent Document 2 discloses a technique for equalizing the heat load in blast furnace operation by intermittently stopping pulverized coal on the opposite side of the direction of high heat load, in order to address the uneven distribution of heat load in the circumferential direction of the furnace body and the deterioration of permeability.

[0007] Furthermore, Patent Document 3 focuses on the fact that when deviations in the pulverized coal flow rate occur in the circumferential direction of the furnace body, the pulverized coal / oxygen ratio changes, causing a difference in tuyere tip temperature in the circumferential direction of the blast furnace body, leading to bias in the reduction reaction inside the furnace and a difference in molten iron temperature in the circumferential direction of the furnace body, which leads to deterioration of the furnace condition.Therefore, Patent Document 3 proposes a method in which the amount of pulverized coal injected is measured for each tuyere or group of tuyeres, and the amount of oxygen injected from the lance is set for each corresponding tuyere or group of tuyeres using the measured values ​​of the amount of pulverized coal injected.

[0008] Furthermore, Patent Document 4 discloses a technique for estimating the amount of coke pulverization and permeability at any position in a blast furnace based on physical factors such as coke strength, reactivity, and reaction temperature, using numerical simulations with discrete element methods and a two-dimensional blast furnace model. This technique enables quantitative evaluation of permeability according to operating conditions using discrete element methods and a two-dimensional blast furnace model.

[0009] Furthermore, Patent Document 5 discloses a technique for predicting the air permeability resistance index of a blast furnace using past operating performance data. This technique uses dimensionality reduction and similarity evaluation based on principal component analysis to construct a local prediction model according to operating conditions, enabling highly accurate prediction of air permeability. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 11-124609 [Patent Document 2] Japanese Patent Publication No. 2004-300504 [Patent Document 3] Japanese Patent Publication No. 2014-31568 [Patent Document 4] Japanese Patent Publication No. 2022-019640 [Patent Document 5] Japanese Patent Publication No. 2015-140455 [Overview of the project] [Problems that the invention aims to solve]

[0011] However, deviations in furnace temperature and heat load in the circumferential direction of the furnace body are not solely caused by variations in the amount of pulverized coal fuel injected in the circumferential direction of the furnace body. Deviations in furnace temperature and heat load in the circumferential direction of the furnace body can also occur, for example, when the center of the charge material from the top of the blast furnace is shifted (charge distribution center shift), and this shift in the distribution of raw materials within the furnace leads to a bias in the gas flow.

[0012] Therefore, there was room for improvement in the methods described in Patent Documents 1 and 2, which conclude that deviations in furnace temperature and heat load in the circumferential direction of the furnace body are caused by variations in the amount of pulverized coal fuel injected in the circumferential direction of the furnace body. Furthermore, when determining the amount of pulverized coal injected based solely on the furnace body temperature, as in Patent Document 1, there is a possibility that a malfunction in the thermometer may lead to the incorrect conclusion that a deviation in the circumferential direction of the pulverized coal flow rate has occurred.

[0013] Furthermore, since Patent Document 3 only measures the deviation of the pulverized coal flow rate in the circumferential direction of the furnace body, if a malfunction occurs in the pulverized coal flow meter, the amount of oxygen supplied will change significantly. As a result, by keeping the theoretical combustion temperature constant depending on the supply air temperature, oxygen enrichment rate, and supply air moisture content, there is a possibility of a high pulverized coal ratio, which carries the risk of unburned pulverized coal. In addition, even if the gas temperature at the tuyeres is uniform, the gas flow may become non-uniform due to localized disturbances in the circumferential balance of raw material descent in the middle of the furnace, making it difficult to completely prevent abnormalities in air permeability, and potentially leading to furnace malfunctions.

[0014] Furthermore, the technology described in Patent Document 4 uses mathematical models to estimate the amount of powdering and air permeability, enabling quantitative evaluation of air permeability according to operating conditions. However, it lacks a function to detect abnormalities in real time during operation, and the estimation of the amount of powdering and air permeability relies on prior model construction and simulation, making it unable to detect sudden abnormalities or warning signs.

[0015] Furthermore, the technology described in Patent Document 5 does not address the real-time detection of abnormal signs during operation or the identification of the spatial location of abnormalities in the circumferential direction of the furnace body; the prediction results are only shown collectively as the ventilation resistance index for the entire blast furnace.

[0016] The present invention has been made in view of the above, and aims to provide a blast furnace malfunction prediction device, a blast furnace malfunction prediction method, a blast furnace operation method, and a molten iron manufacturing method that can predict deterioration of air permeability inside the furnace and abnormal areas in the circumferential direction of the furnace body in advance and in real time by combining the deviation of pulverized coal in the circumferential direction of the furnace body and the deviation of the furnace body temperature in the circumferential direction of the furnace body. [Means for solving the problem]

[0017] To solve the above-mentioned problems and achieve the objective, the blast furnace operational abnormality prediction device according to the present invention comprises: a blast furnace circumferential deviation visualization unit that calculates the deviation of the pulverized coal flow rate and the furnace body temperature in the circumferential direction of the furnace body using the pulverized coal flow rate at each tuyere of the pulverized coal blown into the blast furnace and the furnace body temperature at a plurality of positions in the circumferential direction of the furnace body; an air permeability abnormality prediction unit that determines whether or not there are signs of an air permeability abnormality in the blast furnace based on the deviation of the pulverized coal flow rate and the furnace body temperature in the circumferential direction of the furnace body; and an abnormality prediction alarm unit that, if it is determined that there are signs of an air permeability abnormality, identifies and provides guidance on the parts of the furnace in the circumferential direction of the furnace body where there is a risk of an air permeability abnormality occurring.

[0018] Furthermore, in the blast furnace abnormality prediction device according to the present invention, the permeability abnormality prediction unit determines that there is a sign of the permeability abnormality when the deviation of the pulverized coal flow rate in the circumferential direction of the furnace body exceeds a predetermined threshold for a predetermined time, the deviation of the furnace body temperature in the circumferential direction of the furnace body exceeds a predetermined threshold, and the deviation of the furnace body temperature in the circumferential direction of the furnace body is rising in a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is blown in.

[0019] Furthermore, in the blast furnace operation abnormality prediction device according to the present invention, the permeability abnormality prediction unit predicts fluctuations in permeability resistance based on a statistical model in which the deviation of the pulverized coal flow rate in the circumferential direction of the furnace body and the deviation of the furnace body temperature in the circumferential direction of the furnace body are explanatory variables and the amount of fluctuation in permeability resistance is the dependent variable, and determines that there is an indication of the permeability abnormality when the predicted value of the permeability resistance exceeds a threshold.

[0020] Furthermore, in the blast furnace operation abnormality prediction device according to the present invention, the permeability abnormality prediction unit determines that there is a sign of the permeability abnormality when the predicted value of the fluctuation of the permeability resistance based on the statistical model exceeds a threshold, and furthermore, the deviation of the furnace body temperature in the circumferential direction of the furnace body is increasing in a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is blown in.

[0021] Further, in the operation abnormality prediction device for a blast furnace according to the present invention, in the above invention, the blast furnace circumferential deviation visualization unit visualizes the occurrence location and occurrence timing of the deviation in the circumferential direction of the pulverized coal flow rate and the furnace body temperature with the vertical axis being the azimuth in the circumferential direction of the furnace body of the blast furnace and the horizontal axis being time, by means of the shade of color.

[0022] Further, in the operation abnormality prediction device for a blast furnace according to the present invention, in the above invention, the furnace body temperature is data obtained from a furnace body thermometer installed from the middle part to the lower part of the shaft of the blast furnace.

[0023] Further, in the operation abnormality prediction device for a blast furnace according to the present invention, in the above invention, the furnace body thermometer is installed at a plurality of measurement positions in the height direction of the furnace body and at a plurality of positions in the circumferential direction of the furnace body from the middle part to the lower part of the shaft of the blast furnace, and the furnace body temperature is data of the measurement position in the height direction of the furnace body where the standard deviation of the furnace body temperature in the circumferential direction of the furnace body has increased the most.

[0024] Further, in the operation abnormality prediction device for a blast furnace according to the present invention, in the above invention, the blast furnace circumferential deviation visualization unit further calculates and visualizes the deviation in the circumferential direction of the furnace body pressure using the furnace body pressures at a plurality of positions in the circumferential direction of the furnace body of the blast furnace.

[0025] In order to solve the above-described problems and achieve the object, the operation abnormality prediction method for a blast furnace according to the present invention includes: a blast furnace circumferential deviation visualization step in which a blast furnace circumferential deviation visualization unit provided in a computer calculates the deviation in the circumferential direction of the pulverized coal flow rate and the furnace body temperature using the pulverized coal flow rate for each tuyere into which pulverized coal is blown into the blast furnace and the furnace body temperatures at a plurality of positions in the circumferential direction of the furnace body of the blast furnace; a permeability abnormality prediction step in which a permeability abnormality prediction unit provided in the computer determines the presence or absence of a sign of permeability abnormality in the blast furnace based on the deviation in the circumferential direction of the pulverized coal flow rate and the furnace body temperature; and an abnormality sign notification step in which an abnormality sign notification unit provided in the computer, when it is determined that there is a sign of permeability abnormality, specifies and guides a part in the circumferential direction of the furnace body in the furnace where there is a risk of permeability abnormality occurrence.

[0026] Furthermore, in the blast furnace abnormality prediction method according to the present invention, the permeability abnormality prediction step determines that there is a sign of the permeability abnormality when the deviation of the pulverized coal flow rate in the circumferential direction of the furnace body exceeds a predetermined threshold for a predetermined time, and the deviation of the furnace body temperature in the circumferential direction of the furnace body exceeds a predetermined threshold, and furthermore, in a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is blown in, the deviation of the furnace body temperature in the circumferential direction of the furnace body is rising.

[0027] Furthermore, in the blast furnace operation abnormality prediction method according to the present invention, the permeability abnormality prediction step predicts fluctuations in permeability resistance based on a statistical model in which the deviation of the pulverized coal flow rate in the circumferential direction of the furnace body and the deviation of the furnace body temperature are explanatory variables, and determines that there is an indication of the permeability abnormality when the predicted value of the permeability resistance exceeds a threshold.

[0028] Furthermore, in the blast furnace operation abnormality prediction method according to the present invention, the permeability abnormality prediction step determines that there is a sign of the permeability abnormality when the predicted value of the fluctuation of permeability resistance based on the statistical model exceeds a threshold, and furthermore, the deviation of the furnace body temperature in the circumferential direction of the furnace body is increasing in a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is blown in.

[0029] Furthermore, in the blast furnace operation abnormality prediction method according to the present invention, the blast furnace circumference deviation visualization step visualizes the location and timing of deviations in the circumferential direction of the pulverized coal flow rate and the furnace temperature using varying shades of color, with the vertical axis representing the direction in the circumferential direction of the blast furnace body and the horizontal axis representing time.

[0030] Furthermore, in the blast furnace operation abnormality prediction method according to the present invention, the furnace body temperature is data obtained from a furnace body thermometer installed from the middle to the lower part of the blast furnace shaft.

[0031] Furthermore, in the blast furnace operation abnormality prediction method according to the present invention, the furnace body thermometers are installed at multiple measurement positions in the furnace body height direction and in the furnace body circumferential direction from the middle to the lower part of the blast furnace shaft, and the furnace body temperature is the data from the measurement position in the furnace body height direction where the standard deviation of the furnace body temperature in the furnace body circumferential direction is highest.

[0032] To solve the above-mentioned problems and achieve the objective, the blast furnace operation method according to the present invention includes the step of changing any of the following operating conditions based on the result of determining signs of abnormal air permeability by the above-described blast furnace operation abnormality prediction method: the flow rate of hot air supplied from the tuyere, the amount of oxygen supplied in the hot air supplied from the tuyere, or the coke ratio of the coke charged from the top of the furnace.

[0033] To solve the above-mentioned problems and achieve the objective, the method for manufacturing molten iron according to the present invention manufactures molten iron by the blast furnace operation method described above. [Effects of the Invention]

[0034] According to the blast furnace malfunction prediction device and method of the present invention, even when a deviation in the circumferential direction of the pulverized coal flow rate occurs, deterioration of the permeability inside the furnace can be predicted in advance based on the disturbance of the furnace temperature in the circumferential direction and the anisotropy between the deviation in the circumferential direction of the pulverized coal flow rate and the deviation in the circumferential direction of the furnace temperature. According to the blast furnace operation method of the present invention, deterioration of permeability can be suppressed while avoiding the risk of unburned pulverized coal by encouraging the operation of the blast air flow rate, the amount of blast oxygen (enriched oxygen flow rate), or the coke ratio, rather than adjusting the pulverized coal flow rate. According to the molten iron manufacturing method of the present invention, molten iron can be manufactured with a high yield while maintaining the permeability of the blast furnace. [Brief explanation of the drawing]

[0035] [Figure 1] Figure 1 is a block diagram showing a schematic configuration of a blast furnace operational anomaly prediction device according to an embodiment of the present invention. [Figure 2]Figure 2 is a flowchart showing the processing flow of the blast furnace circumference deviation visualization unit in the blast furnace operation abnormality prediction device according to an embodiment of the present invention. [Figure 3] Figure 3 shows a discussion regarding the results of the visualization of blast furnace circumference deviation in a blast furnace operational anomaly prediction device according to an embodiment of the present invention. [Figure 4] Figure 4 shows the time-series changes in the blast furnace circumference deviation visualization results in a blast furnace abnormality prediction device according to an embodiment of the present invention, specifically the standard deviations of the blast air flow rate, blast air oxygen amount, furnace ventilation resistance, pulverized coal flow rate, furnace body temperature, the circumferential distribution of furnace body temperature and furnace body pressure at the measurement position where the standard deviation was highest, and the pulverized coal flow rate for each tuyeres. [Figure 5] Figure 5 is a flowchart showing the flow of the first embodiment of the processing of the permeability abnormality prediction section in the blast furnace abnormality prediction device according to an embodiment of the present invention. [Figure 6] Figure 6 is a flowchart showing the flow of a second embodiment of the processing of the permeability abnormality prediction section in the blast furnace operation abnormality prediction device according to an embodiment of the present invention. [Figure 7] Figure 7 shows an example 1 of the blast furnace operation abnormality prediction method according to the present invention, and illustrates the changes in the standard deviation of the blast flow rate, blast oxygen rate, pulverized coal flow rate, furnace body temperature, and the air permeability abnormality prediction flag. [Figure 8] Figure 8 shows an example 2 of the blast furnace operation abnormality prediction method according to the present invention, and is a scatter plot with the actual value of the airflow resistance on the horizontal axis and the predicted value of the airflow resistance output from the statistical model on the vertical axis. [Modes for carrying out the invention]

[0036] A blast furnace abnormality prediction device, a blast furnace abnormality prediction method, a blast furnace operation method, and a molten iron manufacturing method according to embodiments of the present invention will be described with reference to the drawings.

[0037] (Configuration of the blast furnace operational anomaly prediction device) Figure 1 is a block diagram showing a schematic configuration of a blast furnace operational anomaly prediction device according to an embodiment of the present invention. The blast furnace operational anomaly prediction device 1 is composed of an information processing device such as a computer, and functions by an internal processing unit such as a CPU (Central Processing Unit) executing a computer program.

[0038] The blast furnace operation database 2 is connected to the operational anomaly prediction device 1 in a data-readable format. A display device 3 is also connected to the operational anomaly prediction device 1.

[0039] The blast furnace operation DB2 stores data such as the following: (1) Actual values ​​of pulverized coal flow rate for each tuyere (2) Actual values ​​of the coke ratio (coke ratio) at the top of the furnace, which indicates the ratio of coke to iron ore charged from the top of the furnace. (3) Actual values ​​of the airflow rate of hot air from the air tuyere (4) Actual values ​​of the amount of oxygen supplied from the air blower nozzle (5) Actual values ​​of the breathability index (6) Actual values ​​of process variables calculated based on the volume fraction of gases (CO, CO2, etc.) emitted from the top of the furnace. (7) Historical data of temperature and pressure measured at the furnace body, top, and bottom.

[0040] Here, an example of an air permeability index is the air resistance index ΔP / V, which is expressed by the following formula (1). In formula (1), BP is the air supply pressure [Pa], TP is the furnace top pressure [Pa], and BGV is the Bosch gas volume [m³]. 3 [Standard conditions] / min]

[0041]

number

[0042] The display device 3 can be implemented using, for example, a liquid crystal display (LCD), an organic light-emitting diode (OLED), or the like. The display device 3 may also constitute part of the operator's control terminal for a blast furnace, for example. The display device 3 may also be equipped with a speaker that outputs an alarm indicating a potential abnormality in air permeability.

[0043] The display device 3 displays, for example, the processing results from the blast furnace circumference deviation visualization unit 11 (standard deviations of pulverized coal flow rate, furnace body temperature, and furnace body pressure) and the processing results from the permeability anomaly prediction unit 12 (presence or absence of signs of permeability anomaly). The display device 3 also displays, for example, the alarm content from the anomaly prediction alarm unit 13 (parts of the furnace body in the circumferential direction where there is a risk of permeability anomaly occurring).

[0044] The blast furnace circumference deviation visualization unit 11 uses the pulverized coal flow rate at each tuyeres of the blast furnace and the furnace body temperature at multiple locations in the circumferential direction of the blast furnace body to calculate the deviation of the pulverized coal flow rate and furnace body temperature in the circumferential direction of the furnace body.

[0045] Here, the furnace body temperature is data obtained from furnace body thermometers installed in the range from the middle to the lower part of the blast furnace shaft. Furthermore, the furnace body temperature is data from the measurement position in the furnace body height direction where the standard deviation of the furnace body temperature in the circumferential direction was highest. Note that multiple furnace body thermometers are installed, for example, in the circumferential direction of the furnace body, at multiple measurement positions in the furnace body height direction and in the furnace body direction, from the middle to the lower part of the blast furnace shaft.

[0046] The operational anomaly prediction device 1, having this configuration, functions as a blast furnace circumference deviation visualization unit 11, a permeability anomaly prediction unit 12, and an anomaly warning unit 13. After predicting permeability anomalies, it notifies the operator of the permeability anomaly warning, for example, through a display device 3.

[0047] The blast furnace circumference deviation visualization unit 11 visualizes the location and timing of deviations in the circumferential direction of the blast furnace body using color intensity, with the vertical axis representing the direction in the circumferential direction of the blast furnace body and the horizontal axis representing time. Furthermore, the blast furnace circumference deviation visualization unit 11 may further calculate and visualize the deviation of the furnace body pressure in the circumferential direction of the blast furnace body using the furnace body pressure at multiple locations in the circumferential direction of the blast furnace body.

[0048] The permeability anomaly prediction unit 12 determines whether or not there are signs of a permeability anomaly in the blast furnace based on the deviations in the circumferential direction of the pulverized coal flow rate and furnace body temperature calculated by the blast furnace circumference deviation visualization unit 11. The permeability anomaly prediction unit 12 determines that there are signs of a permeability anomaly if, for example, all of the following conditions are met. (1) The deviation of the pulverized coal flow rate in the circumferential direction of the furnace body exceeds a predetermined threshold for a predetermined period of time. (2) The deviation of the furnace body temperature in the circumferential direction of the furnace body exceeds a predetermined threshold. (3) In a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is high, the deviation of the furnace body temperature in the circumferential direction of the furnace body is increasing.

[0049] Furthermore, the permeability anomaly prediction unit 12 may predict fluctuations in permeability resistance based on a statistical model in which the deviation of pulverized coal flow rate in the circumferential direction of the furnace body and the deviation of furnace body temperature in the circumferential direction of the furnace body, calculated by the blast furnace circumference deviation visualization unit 11, are explanatory variables, and the amount of fluctuation in permeability resistance is the dependent variable. The permeability anomaly prediction unit 12 may then determine that there is a sign of a permeability anomaly if the predicted value of the permeability resistance exceeds a predetermined threshold.

[0050] Furthermore, the air permeability abnormality prediction unit 12 may determine that there is a sign of an air permeability abnormality if the predicted value of the fluctuation in air permeability resistance based on the statistical model exceeds a threshold, and if the deviation of the furnace body temperature in the circumferential direction of the furnace body is increasing in a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is blown in.

[0051] If the air permeability abnormality prediction unit 12 determines that there is a sign of an air permeability abnormality, the abnormality prediction unit 13 identifies the circumferential part of the furnace body where there is a risk of an air permeability abnormality occurring and provides guidance to the operator, for example, through the display device 3.

[0052] (Processing in the blast furnace circumference deviation visualization section) Next, the processing of the blast furnace circumference deviation visualization unit 11 will be explained with reference to Figure 2. Figure 2 is a flowchart showing the processing flow of the blast furnace circumference deviation visualization unit 11. The flowchart shown in Figure 2 starts when the execution command for blast furnace circumference deviation visualization is input to the operational anomaly prediction device 1, and proceeds to the processing of step S1.

[0053] In step S1, the blast furnace circumference deviation visualization unit 11 acquires blast furnace operation data from the blast furnace operation DB2 (step S1). In step S1, at least flow rate data (pulverized coal flow rate) obtained from flow meters at each tuyere of pulverized coal blown into the blast furnace, and temperature data (furnace temperature) obtained from a plurality of thermometers installed in the circumferential direction of the blast furnace body are acquired. In step S1, preferably, pressure data (furnace pressure) obtained from pressure gauges installed in the circumferential direction of the furnace body in the middle section of the blast furnace body (from the middle of the shaft to the lower part of the shaft) are further acquired.

[0054] Furthermore, the furnace body thermometers and pressure gauges, which are arranged in the circumferential direction of the furnace body, shall be positioned with at least one in each of the four directions (east, west, north, and south), and preferably with two or more in each of the four directions in the circumferential direction of the furnace body.

[0055] Furthermore, for reasons described later, it is preferable that the measurement positions of the furnace body thermometers in the furnace body height direction be from the middle to the lower part of the blast furnace shaft. In addition, it is preferable that the furnace body thermometers be installed at multiple positions in the furnace body height direction and at multiple positions in the furnace body circumferential direction, from the middle to the lower part of the blast furnace shaft.

[0056] In the fusion zone where ore softening and fusion begin, pressure loss is significant, and it is important to detect the deterioration of permeability in the fusion zone. However, as you approach the tuyeres, you are affected by changes in the reducing gas flow. As a result, the noise in the furnace body thermometer measurement data increases as you approach the tuyeres, which may lead to a decrease in the accuracy of anomaly prediction.

[0057] As shown in Figure 3, the shaft of the blast furnace is a frustoconical section in which the furnace diameter increases downwards. The Bosch section of the blast furnace is also a frustoconical section in which the furnace diameter decreases downwards. Inside the blast furnace, between the furnace top and the furnace core, there is a fusion zone, which is a layer that affects the permeability of reducing gases, where the iron ore is in a semi-molten state from the beginning to the end of its melting due to heat. This zone is located from the lower part of the shaft to the middle part of the shaft, above the Bosch section.

[0058] Therefore, it is preferable to provide at least one, preferably two or more, furnace temperature measurement positions in the height direction of the furnace body from the middle to the bottom of the shaft, in both the middle and bottom of the shaft. With this, the process of step S1 is completed, and the blast furnace circumference deviation visualization unit 11 proceeds to the process of step S2.

[0059] In step S2, the blast furnace circumference deviation visualization unit 11 calculates the standard deviations of the pulverized coal flow rate, furnace body temperature, and furnace body pressure for each measurement time (step S2).

[0060] For furnace body temperature, multiple furnace body thermometers are placed in the circumferential direction of the furnace body at each measurement position in the furnace body height direction where the vertical distance from the furnace top is equal, and the standard deviation of the furnace body temperature in the circumferential direction is calculated for each measurement position in the furnace body height direction. Similarly, for furnace body pressure, multiple pressure gauges are placed in the circumferential direction of the furnace body at each measurement position in the furnace body height direction where the vertical distance from the furnace top is equal, and the standard deviation of the furnace body pressure in the circumferential direction is calculated for each measurement position in the furnace body height direction.

[0061] This creates time-series data of furnace body temperature and furnace body pressure, specifically the furnace body circumference deviation (standard deviation in the circumferential direction) for each measurement position in the furnace body height direction. Furthermore, considering that the time constant of the blast furnace process is approximately 8 hours long, it is preferable that the time width of the time-series data be one week or more. With this, the processing in step S2 is completed, and the blast furnace circumference deviation visualization unit 11 proceeds to the processing in step S3.

[0062] In step S3, the blast furnace circumference deviation visualization unit 11 identifies the measurement position in the furnace height direction where the most recent standard deviation in the furnace temperature and furnace pressure in the circumferential direction of the furnace body has increased the most (step S3).

[0063] Since the measurement position in the furnace height direction where an anomaly occurs is not fixed, if, for example, the measurement position in the furnace height direction is fixed, it may not be possible to determine an anomaly if no change is observed in the furnace temperature and furnace pressure at that furnace height position. Therefore, in step S3, the measurement positions for furnace temperature and furnace pressure in the furnace height direction where the most recent standard deviation has increased are identified.

[0064] One method for determining the most recent change in standard deviation is to subtract the moving average of the standard deviation for the most recent day from the moving average of the standard deviation for the most recent hour. With this, the processing in step S3 is completed, and the blast furnace circumference deviation visualization unit 11 proceeds to the processing in step S4.

[0065] In step S4, the blast furnace circumference deviation visualization unit 11 displays a graph showing, for example, the following time-series change on the display device 3 (step S4). (1) Air flow rate (2) Amount of oxygen supplied (3) Air permeability index (furnace ventilation resistance) (4) Standard deviation of pulverized coal flow rate (5) Standard deviation of furnace body temperature (6) The distribution of furnace temperature in the circumferential direction of the furnace body at the measurement position in the furnace body height direction where the most recent standard deviation was highest, as identified in step S3. (7) The distribution of furnace pressure in the circumferential direction of the furnace body at the measurement position in the furnace body height direction where the most recent standard deviation was highest, as identified in step S3. (8) Flow rate of pulverized coal for each tuyeres arranged in the circumferential direction of the furnace body

[0066] Figure 4 shows an example of the display in step S4. In Figure 4, the pulverized coal flow rate, furnace temperature, and furnace pressure for each tuyere arranged in the circumferential direction of the furnace body are shown, with the vertical axis representing the direction of the blast furnace in the circumferential direction, the horizontal axis representing time, and the intensity of the color indicating the magnitude of the value. With this, the processing in step S4 is completed, and the series of processes for visualizing the blast furnace circumferential deviation is finished.

[0067] (Principle of predicting abnormal air permeability) Next, the principle of air permeability abnormality prediction performed by the air permeability abnormality prediction unit 12 will be explained with reference to Figures 3 and 4.

[0068] For example, in Figure 4, at the point indicated by arrow A1, 10 hours before the point where the airflow rate and oxygen supply of hot air blown in from the bottom of the blast furnace were adjusted (indicated as "abnormal airflow"), the circumferential deviation of the pulverized coal flow rate is increasing. Subsequently, at the point indicated by arrow A2, the circumferential deviation of the furnace body temperature is increasing, and at the point indicated by arrow A3, the circumferential deviation of the furnace body pressure is increasing.

[0069] Similar visualizations reveal that there is a time delay of approximately 3 to 5 hours between arrow A1 and arrow A2, that the furnace pressure is locally elevated in the direction with a relatively high pulverized coal flow rate (east), and that the furnace temperature is locally elevated in the direction with a relatively low pulverized coal flow rate (west).

[0070] The cause of the above phenomenon will be explained with reference to Figure 3. For example, in the direction (I) where the flow rate of pulverized coal is relatively high, the pulverized coal does not burn completely and becomes unburned char, which rises in the furnace along with the gas (see the right side of Figure 3). During this rising process, it is thought that the unburned char becomes trapped in the voids of the coke in the coke slit (coke layer), causing clogging and resulting in a localized pressure increase.

[0071] Furthermore, due to the non-uniformity of the gas flow, the gas flow becomes stronger in the direction (II) where the pulverized coal flow rate is relatively low (see the left side of Figure 3). The thickness of the arrows representing the gas flow in Figure 3 indicates the strength of the gas flow rate. As a result, it is thought that the high-temperature gas from the tuyeres also flows towards the furnace wall, causing a localized increase in the furnace body temperature.

[0072] Furthermore, it is presumed that poor air permeability occurs if the furnace body temperature deviation around the furnace circumference (for example, the higher furnace body temperature on the west side in Figure 4) does not resolve during the 3-5 hour time lag until the coke layer containing unburned char descends to the tuyeres.

[0073] Therefore, the inventors identified the following points and believed they could be used to predict abnormalities in air permeability. (1) The relationship between the deviation of the furnace body circumference for pulverized coal flow rate and the deviation of the furnace body circumference for furnace body temperature is anisotropic. That is, for directions in which there is a large amount of pulverized coal flow rate (east side in Figure 4), the furnace body pressure is higher in the same direction (east side in Figure 4), while the furnace body temperature is higher in directions symmetric to the center of the furnace body (west side in Figure 4). (2) There is a lag (time difference) between the timing when the furnace circumference deviation of the pulverized coal flow rate occurs (A1 in Figure 4) and the timing when the furnace circumference deviation of the furnace temperature increases (A2 in Figure 4).

[0074] Based on the above considerations, the permeability anomaly prediction unit 12, as a first mode of permeability anomaly prediction, predicts permeability anomalies in the blast furnace based on deviations in the circumferential direction of the pulverized coal flow rate and furnace body temperature. Specifically, the permeability anomaly prediction unit 12 determines that there are signs of a permeability anomaly if all of the following conditions are met. (1) The deviation of the pulverized coal flow rate in the circumferential direction of the furnace body exceeds a predetermined threshold for a predetermined period of time. (2) The deviation of the furnace body temperature in the circumferential direction of the furnace body exceeds a predetermined threshold. (3) In a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is high, the deviation of the furnace body temperature in the circumferential direction of the furnace body is increasing.

[0075] As mentioned above, there is a lag between the timing when the furnace body circumference deviation of the pulverized coal flow rate occurs (A1 in Figure 4) and the timing when the furnace body circumference deviation of the furnace body temperature expands (A2 in Figure 4). Therefore, the permeability anomaly prediction unit 12 monitors whether the furnace body circumference deviation of the pulverized coal flow rate, for example, at the timing of A1 in Figure 4, continues for a predetermined time (for example, until around A2). Subsequently, it determines whether or not a furnace body circumference deviation of the furnace body temperature has occurred in a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is blown in most.

[0076] Furthermore, as a second aspect of air permeability abnormality prediction, the air permeability abnormality prediction unit 12 may predict fluctuations in air permeability resistance based on a statistical model in which the pulverized coal flow rate and the deviation of the furnace body temperature in the circumferential direction of the furnace body are explanatory variables, and determine that there is a sign of an air permeability abnormality if the predicted value of the air permeability resistance exceeds a predetermined threshold.

[0077] In this case, it is preferable for the permeability abnormality prediction unit 12 to make a future prediction based on the fact that there is a lag between the timing when the furnace body circumference deviation of the pulverized coal flow rate occurs and the timing when the furnace body circumference deviation of the furnace body temperature expands. Furthermore, it may then be determined whether or not a furnace body temperature deviation in the furnace body circumference direction has occurred in a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is blown in.

[0078] (First aspect of predicting abnormal air permeability) Next, the first mode of processing for air permeability abnormality prediction by the air permeability abnormality prediction unit 12 will be explained with reference to Figure 5. Figure 5 is a flowchart showing the flow of the first mode of processing by the air permeability abnormality prediction unit 12. The flowchart shown in Figure 5 starts when an execution command for air permeability abnormality prediction is input to the operational abnormality prediction device 1, and the air permeability abnormality prediction proceeds to step S11.

[0079] In step S11, the permeability anomaly prediction unit 12 determines whether the standard deviation of the pulverized coal flow rate calculated in step S2 of the blast furnace circumference deviation visualization unit 11 has exceeded the threshold α for τ time or longer (step S11).

[0080] The threshold τ in step S11 is preferably set to, for example, 3 to 5 hours, taking into consideration the results of the blast furnace circumference deviation visualization (see Figure 4). If the condition is met in the process of step S11 (Yes in step S11), the air permeability anomaly prediction proceeds to the process of step S12. On the other hand, if the condition is not met in the process of step S11 (No in step S11), the air permeability anomaly prediction terminates the series of processes.

[0081] In step S12, the permeability anomaly prediction unit 12 determines whether the standard deviation of the furnace body temperature calculated in step S2 of the blast furnace circumference deviation visualization unit 11, or the standard deviation of the furnace body temperature at the measurement position in the furnace body height direction where the most recent standard deviation has risen, as identified in step S3, exceeds the threshold β (step S12). If the condition is met in step S12 (Yes in step S12), the permeability anomaly prediction proceeds to step S13. On the other hand, if the condition is not met in step S12 (No in step S12), the permeability anomaly prediction terminates the series of processes.

[0082] In step S13, the permeability anomaly prediction unit 12 determines whether the furnace temperature at the measurement position in the furnace height direction identified in step S3, or the standard deviation of the furnace temperature calculated in step S2 of the blast furnace circumference deviation visualization unit 11, or in a direction point-symmetric with respect to the furnace center, is rising in the direction where the pulverized coal flow rate is relatively high (step S13). Here, unlike the number of tuyeres and the number of measurement points for furnace temperature in the circumferential direction of the furnace, the measurement point for furnace temperature is not necessarily in a position that is perfectly point-symmetric with respect to the location where the pulverized coal flow rate is maximum. Therefore, in step S13, for example, it is determined whether the furnace temperature is maximum at a measurement point within a 45° range clockwise and counterclockwise from a position point-symmetric with respect to the location where the pulverized coal flow rate is maximum.

[0083] If the condition is met in step S13 (Yes in step S13), the air permeability anomaly prediction proceeds to step S14. If the condition is not met in step S13 (No in step S13), the air permeability anomaly prediction terminates the series of processes. In step S14, the air permeability anomaly prediction unit 12 determines that there is a sign of an air permeability anomaly (step S14), and terminates the series of processes.

[0084] (Second aspect of predicting abnormal air permeability) Next, a second mode of processing for air permeability abnormality prediction by the air permeability abnormality prediction unit 12 will be explained with reference to Figure 6. Figure 6 is a flowchart showing the flow of the second mode of processing by the air permeability abnormality prediction unit 12. The flowchart shown in Figure 6 starts when an execution command for air permeability abnormality prediction is input to the operational abnormality prediction device 1, and the air permeability abnormality prediction proceeds to step S21.

[0085] In step S21, the permeability anomaly prediction unit 12 predicts fluctuations in permeability resistance based on a statistical model that includes the standard deviation of the pulverized coal flow rate and the standard deviation of the furnace body temperature at the measurement position in the furnace body height direction where the most recent standard deviation was highest, shifted by time t (lag t), as explanatory variables (step S21). The standard deviation of the pulverized coal flow rate is calculated in step S2 of the processing of the blast furnace circumference deviation visualization unit 11 (see Figure 2). The standard deviation of the furnace body temperature at the measurement position in the furnace body height direction where the most recent standard deviation was highest is identified in step S3 of the processing of the blast furnace circumference deviation visualization unit 11 (see Figure 2).

[0086] In step S21, the lag t is preferably set to 3 to 5 hours, based on the timing of the furnace circumference deviation in pulverized coal flow rate (see A1 in Figure 4) and the timing of the furnace circumference deviation in furnace temperature increasing (see A2 in Figure 4). Examples of statistical models to be used include multiple regression, local PLS, and decision trees. With this, the processing in step S21 is completed, and the air permeability anomaly prediction proceeds to the processing in step S22.

[0087] In step S22, the air permeability anomaly prediction unit 12 determines whether the future predicted value of the air permeability resistance obtained in step S21 exceeds the threshold γ (step S22). If the condition is met in step S22 (Yes in step S22), the air permeability anomaly prediction proceeds to step S23. On the other hand, if the condition is not met in step S22 (No in step S22), the air permeability anomaly prediction terminates the series of processes.

[0088] In step S23, the permeability anomaly prediction unit 12 determines whether the direction in which the pulverized coal flow rate is maximum is point-symmetric with respect to the direction in which the furnace body temperature is maximum (step S23). In step S23, the permeability anomaly prediction unit 12 determines whether the standard deviation of the furnace body temperature calculated in step S2 of the blast furnace circumference deviation visualization unit 11, or the furnace body temperature at the measurement position in the furnace body height direction identified in step S3, is rising in the direction in which the pulverized coal flow rate is relatively high and in the direction in which it is point-symmetric with respect to the center of the furnace body. In step S23, the method for determining whether or not it is point-symmetric is the same as in step S13 in the first embodiment of the processing of the permeability anomaly prediction unit 12.

[0089] If the condition is met in step S23 (Yes in step S23), the air permeability anomaly prediction proceeds to step S24. If the condition is not met in step S23 (No in step S23), the air permeability anomaly prediction terminates the series of processes. In step S24, the air permeability anomaly prediction unit 12 determines that there is a sign of an air permeability anomaly (step S24), and terminates the series of processes.

[0090] (Processing by the abnormal warning system) Next, the processing of the abnormality prediction notification unit 13 will be explained. The processing of the abnormality prediction notification unit 13 begins when an execution command for abnormality prediction is input to the operational abnormality prediction device 1.

[0091] The abnormality prediction unit 13 displays the trend graph generated by the blast furnace circumference deviation visualization unit 11 on the display device 3. Furthermore, if the permeability abnormality prediction unit 12 determines that there is a sign of a permeability abnormality, the abnormality prediction unit 13 may flash and highlight the location where the pulverized coal flow rate and furnace body temperature are at their maximum in the most recent period, and may output an alarm indicating that there is a sign of a permeability abnormality on the trend graph from a speaker or the like (not shown).

[0092] When an abnormality warning is issued by the abnormality warning unit 13, it is preferable to take operational actions to suppress deterioration of airflow, such as reducing the airflow rate or oxygen supply of hot air from the tuyere, or increasing the coke ratio of the coke charged from the top of the furnace.

[0093] According to the first aspect of air permeability abnormality prediction performed by the blast furnace operation abnormality prediction device and blast furnace operation abnormality prediction method described above, even when a deviation in the circumferential direction of the pulverized coal flow rate occurs, deterioration of air permeability inside the furnace and abnormal areas in the circumferential direction of the furnace body can be predicted in advance and in real time based on the disturbance of the furnace body temperature in the circumferential direction and the anisotropy between the deviation of the pulverized coal flow rate in the circumferential direction of the furnace body and the deviation of the furnace body temperature in the circumferential direction of the furnace body.

[0094] Furthermore, according to the second embodiment of the blast furnace operational anomaly prediction device and blast furnace operational anomaly prediction method described above, fluctuations in air permeability can be predicted based on a statistical model that uses the pulverized coal flow rate and the circumferential deviation of the furnace body temperature as explanatory variables, thereby enabling quantitative and highly accurate determination of signs of air permeability anomalies. This improves the detection sensitivity and reliability of the determination of anomaly signs, contributing to the optimization of operating conditions and the prevention of anomalies. In particular, in blast furnace processes where fluctuations in operating conditions are intricately intertwined, prediction using a statistical model enables anomaly prediction that takes into account the correlations of multiple factors, contributing to operational stabilization and improvement of molten iron quality.

[0095] (Blast furnace operation methods) The blast furnace operation abnormality prediction method according to the embodiment may also be applied to the blast furnace operation method. The blast furnace operation method includes a step of changing one of the operating conditions, such as the hot air flow rate from the tuyere, the amount of oxygen in the hot air supplied from the tuyere, or the coke ratio of the coke charged from the top of the furnace, based on the determination result of the blast furnace operation abnormality prediction method for signs of abnormal air permeability. According to the blast furnace operation method according to the embodiment, rather than adjusting the pulverized coal flow rate, the amount of oxygen supplied (enriched oxygen flow rate) or the coke ratio can be manipulated to suppress deterioration of air permeability while avoiding the risk of unburned pulverized coal.

[0096] (Method of producing molten iron) The blast furnace operation method according to the embodiment may also be applied to a method for manufacturing molten iron. In the method for manufacturing molten iron, molten iron is manufactured by the blast furnace operation method described above. According to the method for manufacturing molten iron according to the embodiment, molten iron can be manufactured with a high yield while maintaining the permeability of the blast furnace.

[0097] (Example 1) Embodiment 1 of the blast furnace operation abnormality prediction method according to the present invention will be described with reference to Figure 7. This embodiment corresponds to the first aspect of air permeability abnormality prediction in the blast furnace operation abnormality prediction method according to the present invention. In the blast furnace shown in this embodiment, thermometers are installed in nine stages in the height direction from the middle of the blast furnace shaft to the lower part of the furnace body, and at eight points in the circumferential direction (directions: east, southeast, south, southwest, west, northwest, north, northeast). In addition, in the blast furnace shown in this embodiment, pressure gauges are installed in ten stages in the height direction from the middle of the blast furnace shaft to the lower part of the furnace body, and at four points in the circumferential direction (directions: east, south, west, north). Furthermore, in the blast furnace shown in this embodiment, 42 tuyeres are installed in the circumferential direction.

[0098] The first graph from the top in Figure 7 shows the changes in the blown air flow rate (solid line) and the blown oxygen amount (dashed line) when an abnormal air permeability occurred in the blast furnace and the blown air was operated to avoid the abnormality. The second graph from the top in Figure 7 shows the changes in the standard deviation of the pulverized coal flow rate (solid line) and the threshold α (dotted line) calculated by the blast furnace circumference deviation visualization unit 11. A1 indicates the timing when the standard deviation of the pulverized coal flow rate exceeded the threshold α.

[0099] The third graph from the top in Figure 7 shows the trend of the standard deviation of the furnace body temperature calculated by the blast furnace circumference deviation visualization unit 11 (solid line) and the threshold β (dotted line). A2 indicates the timing when the standard deviation of the furnace body temperature exceeded the threshold β. The fourth graph from the top in Figure 7 shows the air permeability anomaly prediction flag (dashed line) determined by the air permeability anomaly prediction unit 12.

[0100] In this embodiment, the threshold τ was set to 3 hours. As shown in Figure 7, the blast furnace malfunction prediction method according to the present invention makes it possible to set a permeability abnormality prediction flag after A2, when the standard deviation of the furnace body temperature exceeds the threshold β. Therefore, it can be seen that the blast furnace malfunction prediction method according to the present invention makes it possible to predict permeability abnormalities 3 to 14 hours earlier than when permeability abnormalities actually occur in the blast furnace.

[0101] (Example 2) Example 2 of the blast furnace operation abnormality prediction method according to the present invention will be described with reference to Figure 8. This example corresponds to the second aspect of air permeability abnormality prediction in the blast furnace operation abnormality prediction method according to the present invention. The blast furnace shown in Example 2 is the same as the blast furnace shown in Example 1.

[0102] In this embodiment, the lag time t was set to 3 hours. Furthermore, the ventilation resistance was predicted based on a decision tree, using the standard deviation of the pulverized coal flow rate, the standard deviation of the furnace body temperature at the measurement position in the furnace body height direction where the most recent standard deviation was highest (shifted by t time), coke ratio, blown air flow rate, blown air humidity, blown air temperature, total oxygen flow rate, and coke moisture content as explanatory variables.

[0103] Figure 8 shows an example of the results predicted by the air permeability anomaly prediction unit using a statistical model. Figure 8 is a scatter plot with the actual value of air permeability resistance on the horizontal axis and the predicted value of air permeability resistance output from the statistical model on the vertical axis. As shown in Figure 8, it can be seen that the air permeability resistance can be predicted with good accuracy according to the blast furnace operation anomaly prediction method according to the present invention.

[0104] The blast furnace operation anomaly prediction device, blast furnace operation anomaly prediction method, blast furnace operation method, and molten iron manufacturing method 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.

[0105] For example, in the present invention, if the circumferential deviation of the pulverized coal flow rate exceeds a predetermined threshold for a predetermined period of time, and the circumferential deviation of the furnace body pressure exceeds a predetermined threshold, and the furnace body pressure is rising in the same direction as the direction in which the pulverized coal flow rate is blown in, then an abnormality in air permeability may be predicted. [Explanation of symbols]

[0106] 1. Operational Anomaly Prediction Device 11. Blast Furnace Circumference Deviation Visualization Section 12. Air permeability abnormality prediction section 13 Anomaly Prediction Reporting Unit 2. Blast Furnace Operation Database 3 Display device

Claims

1. A blast furnace circumferential deviation visualization unit calculates the deviation of the pulverized coal flow rate and the furnace body temperature in the circumferential direction of the blast furnace, using the pulverized coal flow rate at each tuyere of the pulverized coal being blown into the blast furnace and the furnace body temperature at multiple positions in the circumferential direction of the blast furnace body. A permeability abnormality prediction unit that determines whether or not there are signs of a permeability abnormality in the blast furnace based on the deviation of the pulverized coal flow rate and the furnace body temperature in the circumferential direction of the furnace body, If it is determined that there is a sign of the aforementioned ventilation abnormality, the abnormality prediction alarm unit identifies and provides guidance on the part of the furnace body in the circumferential direction where there is a risk of ventilation abnormality occurring, A blast furnace operational anomaly prediction device equipped with [the following features].

2. The blast furnace operation abnormality prediction device according to claim 1, wherein the permeability abnormality prediction unit determines that there is a sign of the permeability abnormality when the deviation of the pulverized coal flow rate in the circumferential direction of the furnace body exceeds a predetermined threshold for a predetermined time, the deviation of the furnace body temperature in the circumferential direction of the furnace body exceeds a predetermined threshold, and furthermore, in a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is blown in, the deviation of the furnace body temperature in the circumferential direction of the furnace body is increasing.

3. The blast furnace operation abnormality prediction device according to claim 1, wherein the permeability abnormality prediction unit predicts fluctuations in permeability resistance based on a statistical model in which the deviation of the pulverized coal flow rate in the circumferential direction of the furnace body and the deviation of the furnace body temperature in the circumferential direction of the furnace body are explanatory variables and the amount of fluctuation in permeability resistance is the dependent variable, and determines that there is an indication of the permeability abnormality when the predicted value of the permeability resistance exceeds a threshold.

4. The blast furnace operation abnormality prediction device according to claim 3, wherein the air permeability abnormality prediction unit determines that there is a sign of an air permeability abnormality when the predicted value of the fluctuation of air permeability resistance based on the statistical model exceeds a threshold, and further, in a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is blown in, the deviation of the furnace body temperature in the circumferential direction of the furnace body is increasing.

5. The blast furnace operation abnormality prediction device according to claim 1, wherein the blast furnace circumference deviation visualization unit visualizes the location and timing of deviations in the circumferential direction of the blast furnace body using color intensity, with the vertical axis representing the direction of the circumferential direction of the blast furnace body and the horizontal axis representing time.

6. The blast furnace operation abnormality prediction device according to claim 1, wherein the furnace body temperature is data obtained from a furnace body thermometer installed from the middle to the lower part of the shaft of the blast furnace.

7. The furnace body thermometers are installed in multiple locations in the height direction of the furnace body and in the circumferential direction of the furnace body, from the middle to the lower part of the shaft of the blast furnace. The furnace body temperature is the data from the measurement position in the furnace body height direction where the standard deviation of the furnace body temperature in the circumferential direction was highest. The blast furnace operation abnormality prediction device according to claim 6.

8. The blast furnace operation abnormality prediction device according to claim 5, wherein the blast furnace circumference deviation visualization unit further calculates and visualizes the deviation of the furnace body pressure in the circumferential direction of the furnace body using the furnace body pressure at a plurality of positions in the circumferential direction of the blast furnace body.

9. A blast furnace circumference deviation visualization step in which a blast furnace circumference deviation visualization unit equipped with a computer calculates the deviation of the pulverized coal flow rate and the furnace temperature in the circumferential direction of the furnace body using the pulverized coal flow rate at each tuyere of the pulverized coal blown into the blast furnace and the furnace body temperature at multiple positions in the circumferential direction of the blast furnace body, The air permeability anomaly prediction unit of the computer determines whether or not there are signs of an air permeability anomaly in the blast furnace based on the deviation of the pulverized coal flow rate and the furnace body temperature in the circumferential direction of the furnace body, in an air permeability anomaly prediction step, When the abnormality prediction alarm unit of the computer determines that there is an indication of the air permeability abnormality, the abnormality prediction alarm step identifies and provides guidance on the part of the furnace body in the circumferential direction where there is a risk of air permeability abnormality occurring, A method for predicting abnormalities in blast furnace operations, including [specific details omitted].

10. The method for predicting abnormal ventilation in a blast furnace according to claim 9, wherein the aforementioned abnormal ventilation prediction step determines that there is a sign of abnormal ventilation when the deviation of the pulverized coal flow rate in the circumferential direction of the furnace body exceeds a predetermined threshold for a predetermined time, the deviation of the furnace body temperature in the circumferential direction of the furnace body exceeds a predetermined threshold, and furthermore, in a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is blown in, the deviation of the furnace body temperature in the circumferential direction of the furnace body is increasing.

11. The method for predicting abnormalities in the operation of a blast furnace according to claim 9, wherein the permeability abnormality prediction step predicts fluctuations in permeability resistance based on a statistical model in which the deviation of the pulverized coal flow rate in the circumferential direction of the furnace body and the deviation of the furnace body temperature are explanatory variables, and determines that there is a sign of the permeability abnormality when the predicted value of the permeability resistance exceeds a threshold.

12. The method for predicting abnormalities in the operation of a blast furnace according to claim 11, wherein the air permeability abnormality prediction step determines that there is a sign of an abnormal air permeability when the predicted value of the fluctuation of air permeability resistance based on the statistical model exceeds a threshold, and further, in a direction that is point-symmetric with respect to the center of the furnace body with respect to the direction in which the pulverized coal flow rate is blown in, the deviation of the furnace body temperature in the circumferential direction of the furnace body is increasing.

13. The blast furnace operation abnormality prediction method according to claim 9, wherein the blast furnace circumference deviation visualization step involves visualizing the location and timing of deviations in the circumferential direction of the blast furnace body using color intensity, with the vertical axis representing the direction of the circumferential direction of the blast furnace body and the horizontal axis representing time.

14. The method for predicting abnormalities in the operation of a blast furnace according to claim 9, wherein the furnace body temperature is data obtained from a furnace body thermometer installed from the middle to the lower part of the shaft of the blast furnace.

15. The furnace body thermometers are installed in multiple locations in the height direction of the furnace body and in the circumferential direction of the furnace body, from the middle to the lower part of the shaft of the blast furnace. The furnace body temperature is the data from the measurement position in the furnace body height direction where the standard deviation of the furnace body temperature in the circumferential direction was highest. The method for predicting abnormalities in the operation of a blast furnace according to claim 14.

16. A method for operating a blast furnace, comprising the step of changing any of the operating conditions, such as the airflow rate of hot air from the tuyeres, the amount of oxygen in the hot air supplied from the tuyeres, or the coke ratio of the coke charged from the top of the furnace, based on the result of determining signs of an abnormal airflow from the method for predicting abnormal blast furnace operation according to any one of claims 9 to 15.

17. A method for producing molten iron, comprising the operation method of a blast furnace described in claim 16.

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