JP7610107B2 - Blast furnace raw material charging control method, blast furnace raw material charging control device, blast furnace raw material charging control program - Google Patents

Description

The present invention relates to a control method, a control device, and a control program for controlling the charging of coke in a bell-less blast furnace.

In blast furnaces, a charging method is generally used in which ore (including cases where coke is mixed in) and coke are charged alternately from the top of the furnace, forming alternating layers of ore and coke inside the furnace. In order to operate a blast furnace stably, it is important to properly maintain the distribution of the ore and coke deposits inside the blast furnace, in particular the distribution of the layer thickness ratio Lo/(Lc+Lo) in the radial direction of the furnace (where Lo is the ore layer thickness and Lc is the coke layer thickness).

As a means for charging blast furnace raw materials such as ore and coke from the top of the furnace, for example, a bell-less blast furnace equipped with a rotating chute is known. In order to control the layer thickness ratio distribution in a bell-less blast furnace, a conceivable method is to control the tilt angle (including the notch) and/or number of revolutions of the rotating chute to change the falling position and accumulation amount of the blast furnace raw materials in the furnace radial direction, thereby controlling the layer thickness ratio distribution in the furnace radial direction.

Patent Documents 1 and 2 disclose a method for controlling the distribution of charged materials, which is characterized by adjusting the notches and/or number of revolutions of a rotating chute in at least one batch of ore charging so that the layer thickness ratio Lo/(Lc+Lo) at the top of the deposition layer in the furnace satisfies a predetermined condition.

Patent No. 6447470 Patent No. 6327383

Generally, when ore is charged on top of a coke layer, the ore, which has a higher density than the coke, collides with the coke, causing the coke layer to collapse. According to the control methods described in Patent Documents 1 and 2, changing the notch of the rotating chute for charging the ore changes the ore charging position, which changes the collision position in the furnace radial direction with respect to the coke layer, and changes the position where the coke layer collapses and the amount of collapse of the coke layer. This makes it difficult to consider the effect of coke collapse on the layer thickness ratio distribution, making it difficult to adjust the layer thickness ratio distribution.

In view of the above, the present invention aims to provide a blast furnace raw material charging control method, a blast furnace raw material charging control device, and a blast furnace raw material charging control program that can more easily adjust the layer thickness ratio distribution.

In order to solve the above problems, the layer thickness ratio distribution control method according to the present invention is (1) a blast furnace raw material charging control method when ore and coke are charged into a blast furnace from a rotating chute provided at the furnace top and the ore layer and the coke layer are alternately piled up, the method comprising a measuring step, a pile shape specifying step, a layer thickness ratio calculation step, and a rotating chute control step. The measuring step measures the surface shapes of the ore layer and the coke layer piled up in the furnace using a surface shape measuring device provided at the furnace top. The pile shape specifying step specifies the pile shapes of the ore layer and the coke layer based on the measurement results obtained in the measuring step. The layer thickness ratio calculation step calculates the layer thickness ratio Lo/(Lc+Lo) (where Lo: ore layer thickness, Lc: coke layer thickness) of the ore layer and the coke layer for one charge located at the top of the piled up layer in the furnace based on the pile shape specified in the pile shape specifying step. The rotating chute control process controls the tilting angle and/or number of revolutions of the rotating chute when charging coke so as to satisfy the conditions (a) to (d) if the distribution of layer thickness ratios calculated in the layer thickness ratio calculation process does not satisfy the following conditions (a) to (d).
(a) Average value A1 of layer thickness ratio in the first region: 0.0 or more and less than 0.6 (b) Average value A2 of layer thickness ratio in the second region: 0.6 or more and less than 0.9 (c) Average value A3 of layer thickness ratio in the third region: 0.4 or more and less than 0.8 (d) Average value A1 < Average value A3 < Average value A2
However, when the distance from the furnace center in the furnace radial direction is r (m) and the distance from the furnace center to the furnace wall in the furnace radial direction is Rt (m), the first region is a region that satisfies 0.0≦r/Rt≦0.2, the second region is a region that satisfies 0.2<r/Rt≦0.8, and the third region is a region that satisfies 0.8<r/Rt≦1.0.

(2) In the rotating chute control process, when conditions (a) to (d) are satisfied by decreasing any one of the average values A1 to A3, the number of revolutions of the rotating chute loaded into the region where any one of the average values A1 to A3 is decreased is increased.

(3) In the rotating chute control process, when conditions (a) to (d) are satisfied by increasing any one of the average values A1 to A3, the number of revolutions of the rotating chute loaded into the region where any one of the average values A1 to A3 is increased is reduced.

(4) In the rotating chute control process, the tilt angle of the rotating chute is changed so that the coke charging position changes to the furnace center side or the furnace wall side, thereby satisfying conditions (a) to (d).

(5) A blast furnace raw material charging control program for charging ore and coke into a blast furnace through a rotating chute provided at the furnace top and alternately stacking the ore layer and the coke layer, the program causing a computer to execute a stacking shape specifying step, a layer thickness ratio calculating step, and a rotating chute controlling step. The stacking shape specifying step specifies the stacking shapes of the ore layer and the coke layer based on the surface shapes of the ore layer and the coke layer stacked in the furnace measured by a surface shape measuring device provided at the furnace top. The layer thickness ratio calculating step calculates a layer thickness ratio Lo/(Lc+Lo) (where Lo is the ore layer thickness, Lc is the coke layer thickness) of the ore layer and the coke layer for one charge located at the top of the stacking layer in the furnace based on the stacking shape specified in the stacking shape specifying step. The rotating chute control process controls the tilting angle and/or number of revolutions of the rotating chute when charging coke so as to satisfy the conditions (a) to (d) if the distribution of layer thickness ratios calculated in the layer thickness ratio calculation process does not satisfy the following conditions (a) to (d).
(a) Average value A1 of layer thickness ratio in the first region: 0.0 or more and less than 0.6 (b) Average value A2 of layer thickness ratio in the second region: 0.6 or more and less than 0.9 (c) Average value A3 of layer thickness ratio in the third region: 0.4 or more and less than 0.8 (d) Average value A1 < Average value A3 < Average value A2
However, when the distance from the furnace center in the furnace radial direction is r (m) and the distance from the furnace center to the furnace wall in the furnace radial direction is Rt (m), the first region is a region that satisfies 0.0≦r/Rt≦0.2, the second region is a region that satisfies 0.2<r/Rt≦0.8, and the third region is a region that satisfies 0.8<r/Rt≦1.0.

(6) A blast furnace raw material charging control device for charging ore and coke into a blast furnace through a rotating chute provided at the furnace top and alternately stacking an ore layer and a coke layer, the device comprising a processing unit and a control unit. The processing unit executes a stacking shape identification process and a layer thickness ratio calculation process. The control unit executes a rotating chute control process. The stacking shape identification process identifies the stacking shapes of the ore layer and the coke layer based on the surface shapes of the ore layer and the coke layer stacked in the furnace measured using a surface shape measuring device provided at the furnace top. The layer thickness ratio calculation process calculates a layer thickness ratio Lo/(Lc+Lo) (where Lo is the ore layer thickness and Lc is the coke layer thickness) of the ore layer and the coke layer for one charge located at the top of the stacking layer in the furnace based on the stacking shape identified in the stacking shape identification process. The rotating chute control process controls the tilting angle and/or number of revolutions of the rotating chute when charging coke so as to satisfy the conditions (a) to (d) if the distribution of layer thickness ratios calculated in the layer thickness ratio calculation process does not satisfy the following conditions (a) to (d).
(a) Average value A1 of layer thickness ratio in the first region: 0.0 or more and less than 0.6 (b) Average value A2 of layer thickness ratio in the second region: 0.6 or more and less than 0.9 (c) Average value A3 of layer thickness ratio in the third region: 0.4 or more and less than 0.8 (d) Average value A1 < Average value A3 < Average value A2
However, when the distance from the furnace center in the furnace radial direction is r (m) and the distance from the furnace center to the furnace wall in the furnace radial direction is Rt (m), the first region is a region that satisfies 0.0≦r/Rt≦0.2, the second region is a region that satisfies 0.2<r/Rt≦0.8, and the third region is a region that satisfies 0.8<r/Rt≦1.0.

According to the present invention, when charging coke, rather than ore, the distribution of layer thickness ratios can be easily adjusted by controlling the tilt angle and/or number of revolutions of the rotating chute.

1 is an enlarged view of an upper portion of a blast furnace to which a blast furnace raw material charging control method according to the present invention is applied. 1 is a flowchart showing a blast furnace raw material charging control method according to the present invention. FIG. 2 is a diagram showing the deposition shape of one charge of ore layer and coke layer located at the top of the deposition layer in the furnace before applying the blast furnace raw material charging control method according to the present invention (base state). FIG. 4 is a diagram showing the distribution of layer thickness ratios Lo/(Lc+Lo) in the ore layer and the coke layer of FIG. 3 . FIG. 13 is a diagram showing the distribution of the layer thickness ratio Lo/(Lc+Lo) when a method of shifting the notch of a rotating chute during ore charging is applied. FIG. 13 is a diagram showing the distribution of the layer thickness ratio Lo/(Lc+Lo) when a method of shifting the notch of a rotating chute during coke charging is applied.

1 is an enlarged view of the upper part of a blast furnace to which the blast furnace raw material charging control method according to the present embodiment is applied. Referring to FIG. 1, the blast furnace 1 is equipped with a rotating chute 2. The rotating chute 2 is provided at the top of the blast furnace 1, and while rotating in the direction of arrow A around the blast furnace central axis RA, it charges ore and coke supplied from a furnace top bunker (not shown) into the furnace. The direction LC in which the rotating chute 2 extends is inclined at a tilt angle θ with respect to the blast furnace central axis RA, and by changing this tilt angle θ, the falling position of the blast furnace raw materials (ore and coke) in the furnace radial direction can be changed. Usually, the tilt angle θ of the rotating chute 2 is set to several stages, each of which is assigned a number (hereinafter referred to as a notch number). After the rotating chute 2 is rotated once or more times at a predetermined notch number to charge the blast furnace raw materials, the notch number is changed to the next notch number and the charging of the blast furnace raw materials is continued.

The ore and coke in one charge may be charged in multiple batches, or each may be charged in one batch. The ore may be sintered ore, pellets, lump ore, or uncalcined carbon-containing agglomerated ore. The ore may also include materials other than ore (e.g., small lump coke, ferro coke, auxiliary materials, etc.). The driving method of the rotating chute 2 may be any of forward tilting, reverse tilting, and a combination of forward tilting and reverse tilting. Forward tilting refers to a driving method in which the rotating chute 2 is driven from the furnace wall side toward the furnace center side, and reverse tilting refers to a driving method in which the rotating chute 2 is driven from the furnace center side toward the furnace wall side.

A surface shape measuring device 10 is provided at the top of the blast furnace 1. The surface shape measuring device 10 measures the shape (surface shape) of the surface S of the ore layer and coke layer that are charged from the rotating chute 2 and deposited in the furnace. The surface shape measuring device 10 can be a two-dimensional surface shape measuring device (2D profile meter) or a three-dimensional surface shape measuring device (3D profile meter).

When a two-dimensional surface shape measuring device is used, the surface shape in a specific furnace radial direction is measured in one measurement. For example, by installing multiple two-dimensional surface shape measuring devices, it is possible to measure the surface shapes in multiple furnace radial directions. The surface shapes measured in multiple furnace radial directions may be used to determine the surface shapes of unmeasured areas by interpolation, thereby estimating the overall surface shape of the ore layer and coke layer.

The three-dimensional surface shape measuring device measures the surface shapes of the ore layer and the coke layer in the radial direction of the furnace at each predetermined angle in the circumferential direction. The measurement interval of the three-dimensional surface shape measuring device (predetermined angle in the circumferential direction of the furnace) can be set appropriately. If the measurement interval of the three-dimensional surface shape measuring device is wide, the surface shape of the unmeasured area may be determined by interpolation, as in the case of using the above-mentioned two-dimensional surface shape measuring device.

The control device 20, which controls the charging of blast furnace raw materials, includes a processing unit 21 and a control unit 22. The processing unit 21 acquires information on the surface shape of the ore layer and coke layer deposited in the furnace measured by the surface shape measuring device 10, and identifies the deposition shape of the ore layer and coke layer (including the distribution of the deposition layer thickness in the furnace radial direction). Furthermore, based on the identified deposition shape, the processing unit 21 calculates the layer thickness ratio Lo/(Lc+Lo) (where Lo: ore layer thickness, Lc: coke layer thickness) of the ore layer and coke layer for one charge located at the top of the deposition layer in the furnace. The layer thickness ratio Lo/(Lc+Lo) is calculated at multiple positions in the furnace radial direction, and the distribution of the layer thickness ratio Lo/(Lc+Lo) in the furnace radial direction is obtained.

The control unit 22 determines whether the distribution of the layer thickness ratio Lo/(Lc+Lo) calculated by the processing unit 21 satisfies all of the following conditions (a) to (d). If all of the following conditions (a) to (d) are not satisfied, the control unit 22 controls the rotating chute 2 when charging the coke so as to satisfy the conditions (a) to (d). Here, the control of the rotating chute 2 to satisfy the conditions (a) to (d) may be any control that brings the layer thickness ratio distribution closer to the conditions (a) to (d) than the current distribution.

(a) Average value A1 of layer thickness ratio Lo/(Lc+Lo) in the first region: 0.0 or more and less than 0.6 (b) Average value A2 of layer thickness ratio Lo/(Lc+Lo) in the second region: 0.6 or more and less than 0.9 (c) Average value A3 of layer thickness ratio Lo/(Lc+Lo) in the third region: 0.4 or more and less than 0.8 (d) Average value A1 of the first region < average value A3 of the third region < average value A2 of the second region

Each of the average values A1 to A3 is the arithmetic average value of the layer thickness ratios Lo/(Lc+Lo) contained in each region (first region to third region).

For conditions (a) to (d), the first to third regions are regions that divide the entire furnace interior in the furnace radial direction, in order from the furnace center to the furnace wall, assuming that the distance from the furnace center in the furnace radial direction is r (m) and the furnace interior radius at the furnace throat (the distance from the furnace center to the furnace wall) is Rt (m). Specifically, the first region is the region (furnace center) that is defined by 0.0≦r/Rt≦0.2, the second region is the region (furnace middle) that is defined by 0.2<r/Rt≦0.8, and the third region is the region (furnace wall) that is defined by 0.8<r/Rt≦1.0. r/Rt is a dimensionless radius [-] that indicates the position in the furnace radial direction.

By satisfying the above condition (a), the permeability of the first region (furnace center) can be improved, and the gas in the furnace can flow stably. By satisfying the above condition (b), the reduction efficiency in the entire furnace can be improved, and the permeability can be prevented from being locally deteriorated, resulting in uneven distribution of the gas flow in the furnace and delay in the temperature increase and reduction of the ore. By satisfying the above condition (c), the gas flow rate in the furnace wall can be increased, and the growth of zinc and the like attached to the furnace wall can be prevented. By satisfying the above condition (d), the reduction efficiency in the entire furnace can be improved, and an increase in heat loss caused by the average value of the layer thickness ratio Lo/(Lc+Lo) in the third region (furnace wall) being equal to or less than the average value of the layer thickness ratio Lo/(Lc+Lo) in the first region (furnace center) can be prevented.

Methods for controlling the rotating chute 2 when charging coke include controlling the number of revolutions of the rotating chute 2 and controlling the tilt angle (notch) θ of the rotating chute 2.

By controlling the number of revolutions of the rotating chute 2, the amount of coke accumulated near the same coke charging position can be adjusted, and the layer thickness ratio Lo/(Lc+Lo) can be adjusted. Here, the "coke charging position" refers to the position where the charged coke collides with the deposition layer inside the furnace.

As a method for controlling the number of revolutions of the rotating chute 2, for example, when the average value of the layer thickness ratio Lo/(Lc+Lo) in 0.6≦r/Rt≦0.8 is decreased to satisfy the above condition (b), the number of revolutions of the rotating chute 2 at a predetermined notch number when charging coke can be increased. Also, for example, when the average value of the layer thickness ratio Lo/(Lc+Lo) in 0.6≦r/Rt≦0.8 is increased to satisfy the above condition (b), the number of revolutions of the rotating chute 2 at a predetermined notch number when charging coke can be decreased. The above-mentioned "predetermined notch number" may be, for example, "a notch number set at a tilt angle θ such that the position where the average value of the layer thickness ratio Lo/(Lc+Lo) is to be increased or decreased becomes the coke charging position," but is not limited thereto.

By controlling the tilt angle θ of the rotating chute 2, the coke charging position can be adjusted, and the coke deposition distribution in the furnace radial direction can be adjusted, thereby adjusting the layer thickness ratio Lo/(Lc+Lo). Methods for controlling the tilt angle θ of the rotating chute 2 include (A) a method of shifting the notch of the rotating chute 2, and (B) a method of setting the tilt angle θ of the rotating chute 2 to an angle other than the tilt angle θ set by the notch.

(A) As a method of shifting the notches of the rotating chute 2, for example, when charging coke, the layer thickness ratio Lo/(Lc+Lo) can be changed by shifting the notch number located closest to the oven wall by at least one notch toward the oven wall. Also, for example, when charging coke, the layer thickness ratio Lo/(Lc+Lo) can be changed by shifting the notch number located closest to the oven center by at least one notch toward the oven center. Furthermore, the layer thickness ratio Lo/(Lc+Lo) can be changed by shifting multiple notches together by at least one notch toward the oven wall or oven center while maintaining the relative positional relationship of the multiple notches set when charging coke.

(B) As a method of setting the tilt angle θ of the rotating chute 2 to an angle other than the tilt angle θ set for the notch, for example, when the notch numbers for charging coke are set as notch No. 1 (tilt angle θ = 50°), notch No. 2 (tilt angle θ = 48°), notch No. 3 (tilt angle θ = 46°) ..., the tilt angle θ of the rotating chute 2 set for notch No. 1 is set to 49°. This allows the coke charging position for notch No. 1 to be shifted toward the center of the furnace. Also, in the above example, the tilt angle θ of the rotating chute 2 set for notch No. 3 is set to 47°. This allows the coke charging position for notch No. 3 to be shifted toward the furnace wall.

It is also possible to control both the tilt angle θ and the number of revolutions of the rotating chute 2, or to control only one of them.

<Flowchart of blast furnace raw material charging control method>
Fig. 2 is a flow chart of the blast furnace raw material charging control method according to the present embodiment. Referring to Fig. 2, first, the surface shape measuring device 10 measures the surface shapes of the ore layer and the coke layer charged from the rotating chute 2 and deposited in the furnace (step S101). The measurement of the surface shapes is performed immediately after the batch in which the ore and coke are charged. The processing unit 21 identifies the deposition shapes of the ore layer and the coke layer based on the surface shapes of the ore layer and the coke layer measured in step S101 (step S102).

Based on the deposition shapes of the ore layer and the coke layer identified in step S102, the processing unit 21 calculates the layer thickness ratio Lo/(Lc+Lo) of the ore layer and the coke layer for one charge located at the top of the deposition layer in the furnace (step S103). The layer thickness ratio Lo/(Lc+Lo) is calculated in the region from the center of the furnace to the furnace wall, thereby obtaining the distribution of the layer thickness ratio Lo/(Lc+Lo) in the furnace radial direction. When the layer thickness ratio Lo/(Lc+Lo) is calculated based on the surface shapes measured in multiple furnace radial directions by a two-dimensional surface shape measuring device or a three-dimensional surface shape measuring device, the layer thickness ratio Lo/(Lc+Lo) in each furnace radial direction may be the average value of the layer thickness ratio Lo/(Lc+Lo) for each dimensionless radius r/Rt, or the layer thickness ratio Lo/(Lc+Lo) at a specific location (predetermined dimensionless radius r/Rt) may be used as a representative value. On the other hand, the distribution of the layer thickness ratio Lo/(Lc+Lo) in the furnace radial direction may be evaluated based on the rate at which the calculated layer thickness ratio Lo/(Lc+Lo) deviates from the target layer thickness ratio Lo/(Lc+Lo).

The control unit 22 judges whether the distribution of the layer thickness ratio Lo/(Lc+Lo) calculated by the processing unit 21 satisfies all of the above-mentioned conditions (a) to (d) (step S104). If all of the conditions (a) to (d) are satisfied (step S104 Yes), the process shown in FIG. 2 is terminated and the control of step S105 described later is not performed. On the other hand, if all of the conditions (a) to (d) are not satisfied (step S104 No), the control unit 22 controls the tilt angle θ and/or the number of revolutions of the rotating chute 2 when charging the coke so as to satisfy all of the conditions (a) to (d) (step S105). The specific method of controlling the tilt angle θ and/or the number of revolutions of the rotating chute 2 has been described above, so a description thereof will be omitted.

The above-mentioned steps S102 to S105 can be realized by a program, in which a program prepared in advance to realize various processes is stored in an auxiliary storage device, and a process computer such as a CPU reads the program stored in the auxiliary storage device into a main storage device, and the process computer executes the program read into the main storage device. Note that, for step S105, the determination of control parameters for controlling the rotating chute 2 can be realized by a program. The driving of the rotating chute 2 based on the determined control parameters is performed by a driving mechanism that drives the rotating chute 2.

The above program can also be provided to a process computer (e.g., a server) in a state in which it is recorded on a computer-readable recording medium. Examples of computer-readable 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 (e.g., IC chips) that are specially designed and configured for the purpose of the present invention.

According to this embodiment, when adjusting the distribution of the layer thickness ratio Lo/(Lc+Lo) so as to satisfy all of the conditions (a) to (d), the rotating chute 2 is controlled (the control of step S105) only when the coke is charged, and the rotating chute 2 is not controlled (such as the control of step S105) when the ore is charged. This makes it easier to adjust the distribution of the layer thickness ratio Lo/(Lc+Lo) compared to Patent Documents 1 and 2. A specific explanation will be given below.

As in Patent Documents 1 and 2, if the ore charging position is changed by controlling the rotating chute 2, the collision position of the charged ore with respect to the coke layer (the position where the coke layer collapses) changes, so not only the amount of collapse of the coke layer but also the position where the coke layer collapses changes. In this case, if the amount and position of the coke layer collapse are not taken into consideration, it is not possible to adjust the distribution of the layer thickness ratio Lo/(Lc+Lo) to satisfy all of the conditions (a) to (d). Furthermore, as demonstrated in the examples described later, even if the rotating chute 2 during ore charging is controlled to satisfy all of the conditions (a) to (d), the distribution of the actual layer thickness ratio Lo/(Lc+Lo) taking into account the amount and position of the coke layer collapse does not satisfy the conditions (a) to (d).

On the other hand, in this embodiment, the ore charging position is not changed by controlling the rotating chute 2, so although the coke layer collapses due to the collision of the charged ore, the position where the coke layer collapses does not change. On this premise, if the rotating chute 2 is controlled only during coke charging, it becomes easier to adjust the distribution of the layer thickness ratio Lo/(Lc+Lo) so as to satisfy all of the conditions (a) to (d). As demonstrated in the examples described below, if the rotating chute 2 is controlled as in this embodiment, a deviation occurs due to the collapse of the coke layer between the distribution of the layer thickness ratio Lo/(Lc+Lo) that does not take into account the collapse of the coke layer (i.e., the layer thickness ratio calculated from the measurement results of the surface shape) and the distribution of the layer thickness ratio Lo/(Lc+Lo) that takes into account the collapse of the coke layer, but regardless of the distribution, conditions (a) to (d) are satisfied.

The blast furnace raw material charging control method according to the present invention will be described in detail below with reference to examples. In this example, a bell-less test device that is 1/3 the size of an actual furnace was used, and the surface shape of the ore layer and coke layer deposited in the furnace was measured by a surface shape measuring device 10 for each batch of blast furnace raw materials (ore and coke) charged, and the deposition shapes of the ore layer and coke layer were identified based on the measurement results. In one charge, two batches of ore were charged, with ore O1 (first batch) and ore O2 (second batch) being charged in that order. In addition, the coke was charged separately into coke charged in the center of the furnace (center coke) and coke charged in areas other than the center of the furnace (peripheral coke).

Figure 3 is a diagram showing the deposition shape of one charge of ore layer and coke layer located at the top of the deposition layer in the furnace before the application of the present invention (base state). In Figure 3, the vertical axis indicates the position in the furnace height direction, with the upper side being the furnace top side and the lower side being the furnace lower side. The horizontal axis is the dimensionless radius r/Rt(-) indicating the position in the furnace radial direction. In addition, "O2'" shown in Figure 3 indicates the surface of the deposition layer of ore O2 that was charged before the coke layer C was formed. The deposition shape shown in Figure 3 was determined based on the measurement results of the surface profile measuring device 10.

Figure 4 shows the distribution of layer thickness ratio Lo/(Lc+Lo) in the furnace radial direction in the ore layers O1, O2 and coke layer C shown in Figure 3. In Figure 4, the vertical axis is the layer thickness ratio Lo/(Lc+Lo) (-), and the horizontal axis is the dimensionless radius r/Rt (-) indicating the position in the furnace radial direction. The vertical and horizontal axes in Figures 5 and 6 are the same as those in Figure 4. In Figure 4, the layer thickness ratio distribution calculated from the measurement results of the surface shape measuring instrument 10 is shown by a solid line D1, and the target layer thickness ratio distribution is shown by a dashed line D2.

As can be seen from FIG. 4, the layer thickness ratio distribution D1 in the base state is excessively large in the region where the dimensionless radius r/Rt is about 0.4 to about 0.8, and is excessively small in the region where the dimensionless radius r/Rt is about 0.1 to about 0.4, compared to the target layer thickness ratio distribution D2. Therefore, in the region where the layer thickness ratio Lo/(Lc+Lo) is excessively large, the layer thickness ratio Lo/(Lc+Lo) needs to be lowered, and in the region where the layer thickness ratio Lo/(Lc+Lo) is excessively small, the layer thickness ratio Lo/(Lc+Lo) needs to be increased. In consideration of this point, two methods were applied to the ore layer and coke layer shown in FIG. 3: (A) a method of shifting the notch of the rotating chute 2 when charging the ore (comparative example), and (B) a method of shifting the notch of the rotating chute 2 when charging the coke (embodiment).

(A) As a method of shifting the notches of the rotating chute 2 when charging the ore, all notches of the ore O1 located on the furnace center side relative to the notches of the ore O2 were shifted by one notch toward the furnace center side and charged. The ore O2 was charged without changing the notches. Here, the charging of the coke was the same as when forming the coke layer C shown in Figure 3 without changing the notches. Figure 5 shows the layer thickness ratio distribution when the method of shifting the notches of the rotating chute 2 when charging the ore is applied. The solid line A1 in Figure 5 shows the layer thickness ratio distribution calculated from the measurement results of the surface shape measuring device 10, and the solid line A2 in Figure 5 shows the layer thickness ratio distribution taking into account the collapse of the coke layer due to the shifting of the notches. The layer thickness ratio distribution A2 was calculated using a charging distribution estimation model (Iron and Steel, 1987, 73rd year, No. 1, pp. 91-98). According to the burden distribution estimation model, the position and amount of collapse of the coke layer due to the charging of the ore can be estimated, and the deposition shape of the ore layer and the coke layer can be estimated, and the layer thickness ratio distribution A2 can be obtained based on this deposition shape. Figure 5 also shows the target layer thickness ratio distribution D2 shown in Figure 4.

Comparing the layer thickness ratio distribution A1 shown in FIG. 5 with the layer thickness ratio distribution D1 shown in FIG. 4, the layer thickness ratio distribution A1 is closer to the target layer thickness ratio distribution D2 than the layer thickness ratio distribution D1, and the layer thickness ratio distribution appears to have been improved. However, when the collapse of the coke layer (collapse location and amount) caused by the charging of the ore is taken into consideration, the layer thickness ratio distribution A2 shown in FIG. 5 results, which is not very different from the layer thickness ratio distribution D1 shown in FIG. 4, and it was found that the layer thickness ratio distribution has not been improved.

(B) As a method of shifting the notch of the rotating chute 2 when charging coke, the notch located closest to the furnace center was shifted toward the furnace center to charge the coke. Specifically, in the base state shown in FIG. 3, when charging the peripheral coke described above, the coke charging position closest to the furnace center was approximately 0.7 in non-dimensional radius r/Rt, so the notch during coke charging was shifted toward the furnace center so that the coke charging position closest to the furnace center was approximately 0.6 in non-dimensional radius r/Rt. Here, the notch was not changed when charging the ore, and it was the same as when forming the ore layers O1 and O2 shown in FIG. 3.

Figure 6 shows the layer thickness ratio distribution when the method of shifting the notch of the rotating chute 2 during coke charging is applied. The solid line B1 in Figure 6 shows the layer thickness ratio distribution calculated from the measurement results of the surface profile measuring instrument 10. The solid line B2 in Figure 6 shows the layer thickness ratio distribution taking into account the collapse of the coke layer, and the layer thickness ratio distribution B2 was calculated using the charge distribution estimation model described above.

Comparing the layer thickness ratio distribution B1 shown in FIG. 6 with the layer thickness ratio distribution D1 shown in FIG. 4, the layer thickness ratio distribution B1 is closer to the target layer thickness ratio distribution D2 than the layer thickness ratio distribution D1, and the layer thickness ratio distribution has been improved. It was also found that the layer thickness ratio distribution B2 is closer to the target layer thickness ratio distribution D2, and the layer thickness ratio has been improved.

1: Blast furnace 2: Swivel chute 10: Surface shape measuring instrument 20: Control device 21: Processing unit 22: Control unit

Claims (6)

A method for controlling raw material charging into a blast furnace when ore and coke are charged into a blast furnace from a rotating chute provided at the top of the furnace and ore layers and coke layers are alternately piled up, comprising:
a measuring step of measuring the surface shapes of the ore layer and the coke layer deposited in the furnace using a surface shape measuring device provided at the top of the furnace;
a deposition shape identifying step of identifying the deposition shapes of the ore layer and the coke layer based on the measurement results obtained in the measuring step;
a layer thickness ratio calculation step of calculating a layer thickness ratio Lo/(Lc+Lo) (where Lo is the ore layer thickness, Lc is the coke layer thickness) of the ore layer and the coke layer of one charge located at the top of the in-furnace deposition layer based on the deposition shape specified in the deposition shape specification step;
a rotating chute control step of controlling the tilt angle and/or the number of revolutions of the rotating chute when charging coke so as to satisfy the following conditions (a) to (d) when the distribution of the layer thickness ratio calculated in the layer thickness ratio calculation step does not satisfy the following conditions (a) to (d);
A blast furnace raw material charging control method comprising:
(a) the average value A1 of the layer thickness ratio in the first region: 0.0 or more and less than 0.6; (b) the average value A2 of the layer thickness ratio in the second region: 0.6 or more and less than 0.9; (c) the average value A3 of the layer thickness ratio in the third region: 0.4 or more and less than 0.8; (d) the average value A1<the average value A3<the average value A2
However, when the distance from the furnace center in the furnace radial direction is r (m) and the distance from the furnace center to the furnace wall in the furnace radial direction is Rt (m), the first region is a region that satisfies 0.0≦r/Rt≦0.2, the second region is a region that satisfies 0.2<r/Rt≦0.8, and the third region is a region that satisfies 0.8<r/Rt≦1.0. The blast furnace raw material charging control method according to claim 1, characterized in that, in the rotating chute control process, when conditions (a) to (d) are satisfied by decreasing any one of the average values A1 to A3, the number of revolutions of the rotating chute that is charged into an area where any one of the average values A1 to A3 is decreased is increased. The blast furnace raw material charging control method according to claim 1, characterized in that, in the rotating chute control process, when conditions (a) to (d) are satisfied by increasing any one of the average values A1 to A3, the number of revolutions of the rotating chute that is charged into an area where any one of the average values A1 to A3 is increased is reduced. A blast furnace raw material charging control method according to any one of claims 1 to 3, characterized in that in the rotating chute control process, conditions (a) to (d) are satisfied by changing the tilt angle of the rotating chute so that the coke charging position changes to the furnace center side or the furnace wall side. A blast furnace raw material charging control program for charging ore and coke into a blast furnace from a rotating chute provided at the top of the furnace and stacking ore layers and coke layers alternately, comprising:
a deposition shape identifying step of identifying the deposition shapes of the ore layer and the coke layer based on the surface shapes of the ore layer and the coke layer deposited in the furnace measured using a surface shape measuring device provided at the top of the furnace;
a layer thickness ratio calculation step of calculating a layer thickness ratio Lo/(Lc+Lo) (where Lo is the ore layer thickness, Lc is the coke layer thickness) of the ore layer and the coke layer of one charge located at the top of the in-furnace deposition layer based on the deposition shape specified in the deposition shape specification step;
a rotating chute control step of controlling the tilt angle and/or the number of revolutions of the rotating chute when charging the coke so as to satisfy the following conditions (a) to (d) when the distribution of the layer thickness ratio calculated in the layer thickness ratio calculation step does not satisfy the following conditions (a) to (d);
A blast furnace raw material charging control program characterized by causing a computer to execute the above.
(a) the average value A1 of the layer thickness ratio in the first region: 0.0 or more and less than 0.6; (b) the average value A2 of the layer thickness ratio in the second region: 0.6 or more and less than 0.9; (c) the average value A3 of the layer thickness ratio in the third region: 0.4 or more and less than 0.8; (d) the average value A1<the average value A3<the average value A2
However, when the distance from the furnace center in the furnace radial direction is r (m) and the distance from the furnace center to the furnace wall in the furnace radial direction is Rt (m), the first region is a region that satisfies 0.0≦r/Rt≦0.2, the second region is a region that satisfies 0.2<r/Rt≦0.8, and the third region is a region that satisfies 0.8<r/Rt≦1.0. A blast furnace raw material charging control device when ore and coke are charged into a blast furnace from a rotating chute provided at the top of the furnace and ore layers and coke layers are alternately stacked,
A processing unit and a control unit are provided,
The processing unit includes:
a deposition shape identifying step of identifying the deposition shapes of the ore layer and the coke layer based on the surface shapes of the ore layer and the coke layer deposited in the furnace measured using a surface shape measuring device provided at the top of the furnace;
a layer thickness ratio calculation step of calculating a layer thickness ratio Lo/(Lc+Lo) (where Lo is the ore layer thickness, Lc is the coke layer thickness) of the ore layer and the coke layer of one charge located at the top of the in-furnace deposition layer based on the deposition shape specified in the deposition shape specification step;
Run
The control unit is
a rotating chute control process for controlling a tilt angle and/or a number of revolutions of a rotating chute when charging coke so as to satisfy the following conditions (a) to (d) when the distribution of the layer thickness ratio calculated in the layer thickness ratio calculation process does not satisfy the following conditions (a) to (d).
(a) the average value A1 of the layer thickness ratio in the first region: 0.0 or more and less than 0.6; (b) the average value A2 of the layer thickness ratio in the second region: 0.6 or more and less than 0.9; (c) the average value A3 of the layer thickness ratio in the third region: 0.4 or more and less than 0.8; (d) the average value A1<the average value A3<the average value A2
However, when the distance from the furnace center in the furnace radial direction is r (m) and the distance from the furnace center to the furnace wall in the furnace radial direction is Rt (m), the first region is a region that satisfies 0.0≦r/Rt≦0.2, the second region is a region that satisfies 0.2<r/Rt≦0.8, and the third region is a region that satisfies 0.8<r/Rt≦1.0.