JP7614491B2 - Method for determining raw material flow, program for determining flow, device for determining flow, and method for operating blast furnace - Google Patents

Description

The present invention relates to a method, program, and device for determining whether raw materials are flowing into a pile of raw materials charged into a blast furnace, and a method for operating a blast furnace.

When the reducing gas flows from the bottom of the furnace to the top of the furnace, there may be areas in the plane perpendicular to the furnace height direction where the reducing gas can easily pass through and areas where it cannot easily pass through. In areas where the reducing gas can easily pass through, the reduction of the ore is promoted, and the raw materials (ore and coke) descend faster, but in areas where the reducing gas cannot easily pass through, the amount of reduced ore decreases, and the raw materials (ore and coke) descend more slowly.

This can cause height differences in the surface shape of the piled layers of raw materials, and if this height difference increases, the raw materials will collapse, causing a phenomenon known as run-in. In places where raw material run-in occurs, the ratio of ore and coke (O/C) changes, which in turn changes the distribution ratio of reducing gas, causing a decrease in the air permeability and reducibility inside the furnace. In order to stabilize the gas flow inside the furnace, it is first necessary to determine whether or not raw material run-in is occurring. If raw material run-in is occurring, the gas flow inside the furnace can be stabilized by adjusting the method of charging the raw materials to take this run-in into account.

Patent Document 1 describes a blast furnace operation method for detecting the occurrence of raw material flow into a blast furnace. Specifically, multiple ultrasonic sensors installed on the same plane at the blast furnace mouth are used to measure the temperature at multiple measurement points before charging one charge of raw materials and the temperature at multiple measurement points after charging one charge of raw materials. Then, if the temperature at two or more related measurement points after charging the raw materials drops by a predetermined temperature or more compared to before charging the raw materials, it is determined that raw materials have flowed into the position of the raw material pile layer corresponding to the positions of the two or more related measurement points.

Patent No. 6575467

Tetsu-to-Haganen, No. 1, 1987, 73rd year, "Development of a burden distribution estimation model in the bell-less charging method", pp. 91-98

In Patent Document 1, the temperatures of two or more measurement points are measured to determine whether or not raw material has flowed in, and whether or not raw material has flowed in is indirectly determined based on the temperatures of these measurement points. In addition, since the temperature change before and after the charging of raw material at two or more measurement points may not be due to the flow of raw material, the method described in Patent Document 1 may erroneously determine whether or not raw material has flowed in.

Raw material flow occurs when the raw material moves on the surface of the raw material pile. By focusing on this point, the inventors of the present application have found a method to directly determine whether raw material flow is occurring.

In the method for determining whether raw materials are flowing in, which is the first invention of the present application, the surface shape of the uppermost layer of raw materials in a blast furnace is first measured every time a predetermined time has elapsed. Then, when the amount of change in the surface shape before and after the predetermined time has elapsed in a portion of this measurement area is equal to or greater than a reference amount, it is determined that raw materials are flowing in on the surface of the layer. The above-mentioned "surface shape of the uppermost layer of raw materials in a blast furnace" refers to the surface shape of the layer (ore layer or coke layer) that is located at the top of the multiple layers of material stacked in the blast furnace and is formed by the charging of one charge of raw materials (ore or coke).

Here, when the measurement area is divided into a plurality of judgment areas, the above-mentioned amount of change can be obtained in each judgment area. In addition, the direction of the flow of the raw material can be identified based on the position of the judgment area where an amount of change equal to or greater than the reference amount indicates a decrease in the pile height of the surface shape, and the position of the judgment area where an amount of change equal to or greater than the reference amount indicates an increase in the pile height of the surface shape.

In the blast furnace operation method of the second invention of the present application, when it is determined by the inflow determination method of the first invention of the present application that raw material inflow is occurring, the method of charging raw materials is adjusted based on the state of the inflow. Here, the state of raw material inflow includes the position of the raw material inflow destination, the position of the raw material inflow source, and the direction in which the raw materials inflow.

The third invention of the present application, the program for determining whether raw materials are flowing in, causes a computer to execute the steps described below. First, the surface shape of the piled layer of raw materials located at the top of the blast furnace is measured every time a specified time has elapsed. Next, when the amount of change in the surface shape before and after the specified time has elapsed in a portion of the measurement area is equal to or greater than a reference amount, it is determined that raw materials are flowing in on the surface of the piled layer.

The fourth invention of the present application, the raw material flow determination device, obtains the measurement results from a surface shape measuring device that measures the surface shape of the raw material pile layer located at the top of the blast furnace every time a specified time has elapsed. Then, when the amount of change in the surface shape before and after the specified time has elapsed in a portion of the measurement area of the surface shape measuring device is equal to or greater than a reference amount, it determines that raw material flow is occurring on the surface of the pile layer.

According to the present invention, by focusing on the amount of change in the surface shape of the deposition layer before and after a predetermined time has passed, it is possible to determine whether raw material is flowing onto the surface of the deposition layer.

FIG. 2 is a diagram showing the structure of the top of a blast furnace and the configuration of a device for determining the occurrence of raw material inflow. 10 is a flowchart showing a process for determining the occurrence of raw material inflow. FIG. 13 is a diagram illustrating a first partitioning method for a determination region. FIG. 13 is a diagram illustrating a second partitioning method for a determination region. FIG. 13 is a diagram illustrating a third partitioning method for a determination region. FIG. 13 is a diagram showing the positions of two determination regions. FIG. 13 is a diagram showing changes in pile height over time in two determination regions.

In this embodiment, it is possible to determine whether localized flow of raw materials has occurred or whether no flow of raw materials has occurred on the surface of the deposition layer formed by charging raw materials into a blast furnace. Here, the raw materials include coke and ore, and in the blast furnace, a deposition layer of coke (hereinafter referred to as the "coke layer") and a deposition layer of ore (hereinafter referred to as the "ore layer") are alternately formed in the furnace height direction. In this embodiment, it is possible to determine whether flow of raw materials has occurred or whether no flow of raw materials has occurred for each of the coke layer and the ore layer.

First, the structure of the top of the blast furnace and the configuration of the device for determining the occurrence of raw material inflow will be explained with reference to Figure 1. The blast furnace 1 shown in Figure 1 is a bell-less type blast furnace.

A chute 2 is provided at the top of the blast furnace 1, and the chute 2 rotates around a rotation axis RA, as indicated by arrow A. Here, the rotation axis RA coincides with the center of the furnace. The angle θ at which the chute 2 tilts with respect to the rotation axis RA (hereinafter referred to as the "tilt angle") can be changed. Raw materials are supplied to the chute 2 from a hopper (not shown) that contains the raw materials, and as the chute 2 rotates, the raw materials are charged into the furnace from the tip of the chute 2.

The surface shape measuring device 10 is placed at the top of the blast furnace 1 and measures the surface shape of the sedimentary layer S located at the topmost position in the furnace. For example, a 2D profile meter or a 3D profile meter can be used as the surface shape measuring device 10. The surface shape measuring device 10 is connected to the determination device 20 wirelessly or via a wire, and the measurement results of the surface shape measuring device 10 (the surface shape of the sedimentary layer S) are transmitted to the determination device 20.

Based on the measurement results of the surface shape measuring instrument 10, the determination device 20 determines whether or not raw material flow is occurring on the surface of the deposition layer S. The determination device 20 has a calculation unit 21 and a memory 22.

Next, the process of determining whether or not raw material inflow is occurring will be explained based on the flowchart shown in Figure 2.

In step S101, the determination device 20 acquires the measurement results of the surface shape of the deposition layer S (hereinafter referred to as "surface shape information") from the surface shape measuring device 10. The surface shape information includes the height from the reference position to the surface of the deposition layer S (hereinafter referred to as "deposition height"). The acquired surface shape information is stored in the memory 22.

The calculation unit 21 of the determination device 20 divides the measurement region Rm measured by the surface shape measuring instrument 10 into multiple determination regions Rd. The measurement region Rm is the region of the entire surface of the deposition layer S that is to be measured by the surface shape measuring instrument 10. The determination region Rd is each of the multiple regions formed by dividing the measurement region Rm. The above-mentioned surface shape information includes the surface shape in the measurement region Rm, but by dividing the measurement region Rm into multiple determination regions Rd, the surface shape in each determination region Rd can be identified.

Here, three examples of methods for dividing the measurement region Rm into multiple determination regions Rd are described below. Note that the determination region Rd is only used to identify the position where the flow of raw material occurs (i.e., the position within the measurement region Rm), so the method for dividing the determination region Rd is not limited to the method described below.

The first partitioning method will be explained with reference to FIG. 3. FIG. 3 shows the measurement area Rm measured by the surface shape measuring device 10, which corresponds to an area in a plane perpendicular to the furnace height direction. The outer edge of the measurement area Rm corresponds to the inner circumferential surface of the furnace wall of the blast furnace 1, and the center of the measurement area Rm corresponds to the center of the blast furnace 1.

As shown in FIG. 3, the measurement area Rm is partitioned (divided) into multiple judgment areas Rd by multiple partition lines (dotted lines) DL. One judgment area Rd is an area surrounded by multiple partition lines DL. The partition lines DL include partition lines DL extending in the radial direction of the measurement area Rm (i.e., in the furnace radial direction) and partition lines DL that are circles centered at the center of the measurement area Rm (i.e., the furnace center) and extend in the furnace circumferential direction. The number of partition lines DL and the number of judgment areas Rd can be determined as appropriate.

The second partitioning method will be explained with reference to FIG. 4. FIG. 4 shows the measurement area Rm measured by the surface shape measuring device 10, which corresponds to an area in a plane perpendicular to the furnace height direction. The outer edge of the measurement area Rm corresponds to the inner circumferential surface of the furnace wall of the blast furnace 1, and the center of the measurement area Rm corresponds to the center of the blast furnace 1.

As shown in FIG. 4, the measurement area Rm is partitioned (divided) into a number of judgment areas Rd by a number of demarcation lines (dotted lines) DL. One judgment area Rd is an area surrounded by a number of demarcation lines DL. The demarcation lines DL include demarcation lines DL extending in a first direction (the up-down direction in FIG. 4) and demarcation lines DL extending in a second direction (the left-right direction in FIG. 4) perpendicular to the first direction. The number of demarcation lines DL and the number of judgment areas Rd can be determined as appropriate.

The third partitioning method will be explained with reference to FIG. 5. FIG. 5 shows the measurement area Rm measured by the surface shape measuring device 10, which corresponds to an area in a plane perpendicular to the furnace height direction. The outer edge of the measurement area Rm corresponds to the inner circumferential surface of the furnace wall of the blast furnace 1, and the center of the measurement area Rm corresponds to the center of the blast furnace 1.

As shown in FIG. 5, the measurement area Rm is partitioned (divided) into multiple judgment areas Rd by multiple demarcation lines (dotted lines) DL. The multiple judgment areas Rd include a judgment area Rd surrounded by one demarcation line DL (a judgment area Rd located at the center of the measurement area Rm) and a judgment area Rd surrounded by two adjacent demarcation lines DL in the radial direction of the measurement area Rm (i.e., the furnace radial direction). Each demarcation line DL is a circle centered at the center of the measurement area Rm (i.e., the furnace center) and extends in the furnace circumferential direction. The number of demarcation lines DL and the number of judgment areas Rd can be determined as appropriate.

In step S102 shown in FIG. 2, the determination device 20 determines whether a predetermined time Δt has elapsed since the measurement result of the surface shape was obtained in the process of step S101. The device waits until the predetermined time Δt has elapsed, and if the predetermined time Δt has elapsed, the device proceeds to the process of step S103. The predetermined time Δt can be determined as appropriate, but can be set to, for example, 20 seconds.

The predetermined time Δt is a period for determining the amount of change ΔHm, which will be described later, and the amount of change ΔHm is a parameter for determining whether or not an inflow of raw materials is occurring. Here, if the predetermined time Δt is too long, the amount of change ΔHm will include, in addition to the amount of change caused by the inflow of raw materials, the amount of change caused by the lowering of the sediment layer in the furnace and the amount of change caused by the charging of new raw materials, making it difficult to determine whether or not an inflow of raw materials is occurring. Taking this into consideration, the predetermined time Δt can be determined. For example, the predetermined time Δt can be set to be equal to or less than the time from the start to the end of charging one dump of raw materials (coke or ore).

In step S103, the determination device 20 acquires surface shape information (including deposition height) from the surface shape measuring device 10. The acquired surface shape information is stored in the memory 22. As described above, the calculation unit 21 of the determination device 20 divides the measurement region Rm measured by the surface shape measuring device 10 into a plurality of determination regions Rd.

In step S104, the calculation unit 21 of the determination device 20 calculates the amount of change ΔHm in the pile height based on the surface shape information acquired in the processing of steps S101 and S103. Here, the calculation of the amount of change ΔHm is for the determination area Rd located at the same position within the measurement area Rm. The amount of change ΔHm is the value (ΔHm = H2 - H1) obtained by subtracting the pile height H2 included in the surface shape information acquired in the processing of step S103 from the pile height H1 included in the surface shape information acquired in the processing of step S101 for each determination area Rd.

In one judgment region Rd, the pile height is not constant, and a distribution (variation) of the pile height may occur. Therefore, as the pile height of each judgment region Rd (the pile heights H1 and H2 described above), it is necessary to specify one pile height for one judgment region Rd. When specifying one pile height, for example, the average value of all pile heights included in the judgment region Rd, the maximum pile height included in the judgment region Rd, or the minimum pile height included in the judgment region Rd can be specified.

The amount of change ΔHm (ΔHm = H2 - H1) may be a negative value or a positive value. In other words, when the pile height H1 is higher than the pile height H2, the amount of change ΔHm is a negative value, and when the pile height H1 is lower than the pile height H2, the amount of change ΔHm is a positive value.

In step S105, the calculation unit 21 determines whether the absolute value of the change amount ΔHm calculated in the processing of step S104 is equal to or greater than the reference amount (positive value) ΔHref. As described above, since the change amount ΔHm may indicate a negative value or a positive value, the absolute value of the change amount ΔHm is used in the comparison with the reference amount ΔHref. In addition, a positive value is used as the reference amount ΔHref. Here, if the change amount (absolute value) ΔHm is equal to or greater than the reference amount ΔHref, the processing proceeds to step S106, and if the change amount (absolute value) ΔHm is less than the reference amount ΔHref, the processing proceeds to step S107.

The reference amount ΔHref is a value for determining whether or not an inflow of raw material is occurring, and can be determined as appropriate. Information regarding the reference amount ΔHref can be stored in memory 22. As a method for determining the reference amount ΔHref, for example, one of the three determination methods described below can be used.

In the first determination method, a predetermined amount taking into consideration past operating results can be set as the reference amount ΔHref. Here, the reference amount ΔHref can be determined for each judgment region Rd, and the reference amounts ΔHref in multiple judgment regions Rd may be different from each other.

In the second determination method, the maximum change amount ΔHm is identified among the change amounts ΔHm calculated for multiple judgment regions Rd that are located at the same radial position in the furnace (in other words, multiple judgment regions Rd lined up in the circumferential direction of the furnace), and the average value of the multiple change amounts ΔHm (maximum amounts) identified within a specified period can be set as the reference amount ΔHref.

In the third determination method, the change in pile height estimated from the charge distribution estimation model described in Non-Patent Document 1 can be set as the reference amount ΔHref. By using the charge distribution estimation model described above, it is possible to estimate the change in pile height ΔHe when raw materials are charged, assuming that no raw material flow occurs. Then, this change ΔHe can be set as the reference amount ΔHref.

When the amount of change (absolute value) ΔHm calculated in the processing of step S104 is greater than the amount of change ΔHe, the pile height rises or falls by the amount of raw material flowing in. Specifically, at the position where the raw material flows in (the destination of movement), the pile height rises by the amount of raw material flowing in. Also, at the position where the raw material flows in (the source of movement), the pile height falls by the amount of raw material flowing in.

In step S106, the determination device 20 determines that the flow of raw material is occurring on the surface of the deposition layer S. In step S107, the determination device 20 determines that the flow of raw material is not occurring on the surface of the deposition layer S.

When the amount of change (absolute value) ΔHm is equal to or greater than the reference amount ΔHref and is a positive value, the pile height H2 is higher than the pile height H1, meaning that the pile height is rising. By focusing on the judgment region Rd where the amount of change ΔHm is a positive value, it is possible to determine the position of the flow-in (destination) of the raw material when it flows in.

On the other hand, if the amount of change (absolute value) ΔHm is equal to or greater than the reference amount ΔHref and is a negative value, this means that the pile height H2 is lower than the pile height H1, and the pile height is decreasing. By focusing on the determination region Rd where the amount of change ΔHm is a negative value, it is possible to determine the position of the source of the flow (the source of movement) when the flow of raw material occurs.

As mentioned above, if the source (position) and destination (position) of the raw material are known, the direction of the raw material flow can be determined. In other words, the direction from the source (position) to the destination (position) is the direction of the raw material flow.

The direction in which the raw materials flow can be from the furnace wall side toward the furnace center side (hereinafter referred to as the "furnace radial direction") or the furnace circumferential direction. If multiple determination regions Rd are defined as shown in Figures 3 and 4, the furnace radial direction or the furnace circumferential direction can be identified as the direction in which the raw materials flow. If multiple determination regions Rd are defined as shown in Figure 5, the furnace radial direction can be identified as the direction in which the raw materials flow.

According to the flowchart shown in FIG. 2, the amount of change ΔHm is calculated each time a predetermined time Δt has elapsed, and based on a comparison of the amount of change (absolute value) ΔHm and a reference amount ΔHref, it is determined whether or not an inflow of raw materials has occurred. Note that, although the processing of steps S106 and S107 is performed in the flowchart shown in FIG. 2, it is possible to perform the processing of step S106 and omit the processing of step S107. In this case, it is only necessary to determine whether an inflow of raw materials has occurred.

Figures 6 and 7 show an example of how to calculate the change amount ΔHm.

Figure 6 shows two judgment regions Rd located within the measurement region Rm, one judgment region Rd is located at a position where the dimensionless radius is 0.2 [-], and the other judgment region Rd is located at a position where the dimensionless radius is 0.4 [-]. The dimensionless radius is a value in the blast furnace 1 normalized by taking the actual distance from the center of the furnace to the inner surface of the furnace wall as 1.0. Note that the dotted line shown in Figure 6 is a line extending in the furnace radial direction.

Figure 7 shows the change over time in the pile height of the sediment layer S after the raw materials are charged into the furnace for the two judgment regions Rd shown in Figure 6. Here, the timing when the raw materials are charged is set to 0 [sec]. As shown in Figure 7, the amount of change ΔHm can be calculated from the pile height before the predetermined time Δt has elapsed (the pile height H1 described above) and the pile height after the predetermined time Δt has elapsed (the pile height H2 described above).

In this embodiment, in the process of step S102, the determination device 20 determines whether or not a predetermined time Δt has elapsed, but this is not limited to this. For example, the period for transmitting the surface shape measurement results (surface shape information) from the surface shape measuring instrument 10 to the determination device 20 can be set to the above-mentioned predetermined time Δt. This allows the determination device 20 to obtain the surface shape measurement results (surface shape information) from the surface shape measuring instrument 10 every time the predetermined time Δt has elapsed.

In addition, in this embodiment, the amount of change ΔHm is calculated in each judgment region Rd, but this is not limited to this. Specifically, multiple adjacent judgment regions Rd are treated as one judgment region Rd_g, and the amount of change ΔHm in this judgment region Rd_g is compared with a reference amount ΔHref, so that it is possible to determine whether or not an inflow of raw material is occurring.

When calculating the amount of change ΔHm in the judgment region Rd_g, the average value (or total value) of the pile heights in the multiple judgment regions Rd included in the judgment region Rd_g is calculated, and the difference between these average values (or total values) can be used as the amount of change ΔHm. In addition, the reference amount ΔHref can be determined according to the value of the pile height when calculating the amount of change ΔHm (the average value or total value described above).

If it is determined in the processing of step S106 that raw materials are flowing in, it can notify that action will be taken to adjust the raw material charging method described below. This notification can be given by voice or display on a display. It can also notify information regarding the source (location) and destination (location) of the raw materials in order to adjust the raw material charging method.

When raw materials flow in, the deterioration of the air permeability and reducibility inside the blast furnace can be prevented by adjusting the raw material charging method according to the state of this flow. An example of adjusting the raw material charging method is explained below.

If the ore (raw material) flows into the center of the furnace after it has been charged into the furnace, the next coke to be charged can be charged in excess toward the center of the furnace.

Specifically, the amount of coke charged into the center of the furnace (hereinafter referred to as "center coke") can be increased. On the other hand, by rotating the chute 2 while changing the tilt angle θ of the chute 2, the number of revolutions of the chute 2 at the position (notch) on the furnace center side can be increased when charging coke (hereinafter referred to as "peripheral coke") into areas other than the center of the furnace. By increasing the number of revolutions of the chute 2, the amount of peripheral coke charged into the area on the furnace center side can be increased.

When ore flows into the center of the furnace and the change in the pile height of the ore layer in the furnace wall area is small, the next ore to be charged can be excessively charged in the furnace wall area. Specifically, by rotating the chute 2 while changing the tilt angle θ of the chute 2, the number of revolutions of the chute 2 at the position (notch) on the furnace wall side can be increased when charging the ore. By increasing the number of revolutions of the chute 2, the amount of ore charged to the furnace wall area can be increased. Note that a reference amount can be determined in advance to determine whether the change in the pile height of the ore layer is small or not.

If coke flows into the center of the furnace after it has been charged into the furnace, the next coke to be charged can be excessively charged toward the furnace wall side. Specifically, when charging peripheral coke as described above, the amount of coke charged to the furnace wall area can be increased by increasing the number of revolutions of the chute 2 at the position (notch) on the furnace wall side.

As described above, the amount of raw material (coke or ore) to be increased can be determined based on the change amount ΔHm. For example, if the correlation between the amount of increase in raw material and the change amount ΔHm is determined in advance, it is possible to determine the amount of increase in raw material that corresponds to the calculated change amount ΔHm.

When raw materials (ore or coke) flow into the furnace circumferential direction, the amount of reducing gas blown in from multiple tuyere arranged in the furnace circumferential direction can be adjusted. Specifically, the amount of air blown from the tuyere located below the furnace height direction relative to the position where the raw materials flowed in (the position where the pile height has increased) is not changed, while the amount of air blown from the other tuyere is reduced. When the amount of air blown from multiple other tuyere is reduced, the amount of air blown from the other tuyere can be adjusted so that the total amount of air blown from all other tuyere is reduced by a predetermined amount.

The processes (so-called functions) described in FIG. 2 can be realized by a program. Specifically, computer programs prepared in advance to realize each function are stored in an auxiliary storage device, and a control unit such as a CPU reads the programs stored in the auxiliary storage device into a main storage device, and the control unit executes the programs read into the main storage device, thereby operating each function. Each function can be operated by a single control device, or by multiple control devices connected to each other.

The above program can also be provided to a computer in a state in which it is recorded on a computer-readable recording medium. Examples of recording media include optical disks such as CD-ROMs, phase-change optical disks such as DVD-ROMs, magneto-optical disks such as MO (Magnet Optical) and MD (Mini Disk), magnetic disks such as floppy (registered trademark) disks and removable hard disks, and memory cards such as Compact Flash (registered trademark), Smart Media, SD memory cards, and memory sticks. Also included as recording media are hardware devices such as integrated circuits (IC chips, etc.) that are specially designed and configured for the purposes of the present invention.

Using a 3D profile meter (surface shape measuring device 10 shown in Figure 1) installed at the top of the blast furnace, the surface shape of the sediment layer S charged into the furnace was measured at a period of 20 seconds (predetermined time Δt). The amount of change ΔHm was calculated based on the surface shape (sediment height) at the start of the 20-second count and the surface shape (sediment height) after 20 seconds had elapsed, and it was determined whether the amount of change (absolute value) ΔHm was equal to or greater than the reference amount ΔHref. Here, the reference amount ΔHref was set to 250 mm.

When the ore was charged, the change amount ΔHm in the judgment region Rd at the position where the dimensionless radius is 0.2 was 350 mm, which was larger than the reference amount ΔHref (250 mm). In addition, when the change amount ΔHm in each of the multiple judgment regions Rd included in the measurement region Rm was checked, it was confirmed that the ore had flowed from the furnace wall side to the furnace center side.

Therefore, when the next coke was charged, the amount of central coke was increased by 0.3 tons. As a result, stable operation could be continued without causing deterioration of permeability or circumferential deviation of the tapping iron.

1: blast furnace, 2: chute, 10: surface shape measuring device, 20: judgment device, 21: calculation unit,
22: memory, S: deposition layer

Claims (6)

Measure the surface shape of the uppermost layer of the raw material deposit in the blast furnace every time a predetermined time has elapsed, which is equal to or shorter than the time from the start of charging the raw materials to the end of charging the raw materials ;
A method for determining raw material inflow, characterized in that when the amount of change in the surface shape before and after the specified time has elapsed in a portion of the measurement area is greater than or equal to a reference amount, it is determined that raw material inflow is occurring on the surface of the deposition layer. The method for determining the flow of raw material according to claim 1, characterized in that the amount of change is calculated in each of the determination regions when the measurement region is divided into a plurality of determination regions. The method for determining the inflow of raw material according to claim 2, characterized in that the direction of inflow of raw material is identified based on the position of the determination region where the amount of change above the reference amount indicates a decrease in the pile height of the surface shape, and the position of the determination region where the amount of change above the reference amount indicates an increase in the pile height of the surface shape. A method for operating a blast furnace, comprising the steps of: determining, by the method for determining inflow of raw materials according to any one of claims 1 to 3, that the inflow of raw materials is occurring; and adjusting a method for charging raw materials so as to improve the air permeability or reducibility inside the blast furnace based on a surface shape of the sediment layer after the inflow. A step of measuring a surface shape of a sedimentary layer of raw materials located at the top of the blast furnace every time a predetermined time has elapsed, which is equal to or shorter than the time from the start of charging of the raw materials to the end of charging ;
determining that a flow of raw material is occurring on the surface of the deposition layer when the amount of change in the surface shape before and after the predetermined time has elapsed is equal to or greater than a reference amount in a portion of the measurement area;
A raw material flow determination program that causes a computer to execute the above steps. Obtaining the measurement results from a surface shape measuring device that measures the surface shape of the uppermost layer of the raw material pile in the blast furnace every time a predetermined time has elapsed, which is equal to or shorter than the time from the start of charging the raw materials to the end of charging the raw materials ;
A raw material flow determination device characterized by determining that raw material flow is occurring on the surface of the deposition layer when the amount of change in the surface shape before and after the specified time has elapsed is equal to or greater than a reference amount in a portion of the measurement area of the surface shape measuring instrument.