Blast furnace raw material charging control method, blast furnace raw material charging control device, blast furnace raw material charging control program

Abstract

To provide a blast furnace raw material charge control method that can more easily adjust the layer thickness ratio distribution.SOLUTION: An angle and / or number of turns of a swirling chute for charging coke is controlled so that the layer thickness ratio Lo / (Lc+Lo) (Lo: ore layer thickness, Lc: coke layer thickness) of one charge of ore and coke layers, determined based on the surface profiles of ore and coke layers deposited in the furnace, satisfies the following conditions (a)-(d). (a) Average layer thickness ratio within a first region (0.0≤r / Rt≤0.2): 0.0 or more and less than 0.6. (b) Average layer thickness ratio within a second region (0.2<r / Rt≤0.8): 0.6 or more and less than 0.9. (c) Average layer thickness ratio within a third region (0.8<r / Rt≤1.0): 0.4 or more and less than 0.8. (d) The average within the first region<the average within the third region<the average within the second region.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control method, a control device, and a control program for controlling coke charging in a bell-less type blast furnace. [Background technology]

[0002] In blast furnaces, a charging method is generally adopted in which ore (including cases where coke is mixed) and coke are charged alternately from the top of the furnace, forming alternate layers of ore and coke inside the furnace. In order to operate the blast furnace stably, it is important to appropriately maintain the distribution of the ore and coke deposits in the blast furnace, particularly 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).

[0003] As a means for charging blast furnace raw materials such as ore and coke from the furnace top, 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 method can be considered in which the tilt angle (including the notch) and / or the number of revolutions of the rotating chute is controlled 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.

[0004] Patent Documents 1 and 2 disclose a method for controlling the distribution of charged materials, which is characterized by adjusting the notch and / or the 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. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6447470 [Patent Document 2] Patent No. 6327383 Summary of the Invention [Problem to be solved by the invention]

[0006] Generally, when ore is charged on 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, when the notch of the rotating chute for charging the ore is changed, the charging position of the ore is changed, so that the collision position with the coke layer in the furnace radial direction changes, and the position where the coke layer collapses and the amount of the coke layer collapse change. Therefore, it is difficult to consider the effect of coke collapse on the layer thickness ratio distribution, and it is difficult to adjust the layer thickness ratio distribution.

[0007] In view of the above, an object of the present invention is 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. [Means for solving the problem]

[0008] 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 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 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 the layer thickness ratio in the first region: 0.0 or more and less than 0.6 (b) Average value A2 of the layer thickness ratio in the second region: 0.6 or more and less than 0.9 (c) Average value A3 of the 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 diameter direction is r (m) and the distance from the furnace center to the furnace wall in the furnace diameter direction is Rt (m), the first region is a region satisfying 0.0 ≦ r / Rt ≦ 0.2, the second region is a region satisfying 0.2 < r / Rt ≦ 0.8, and the third region is a region satisfying 0.8 < r / Rt ≦ 1.0.

[0009] (2) In the swivel chute control step, when satisfying conditions (a) to (d) by decreasing any one of the average values A1 to A3, increase the number of revolutions of the swivel chute charged into the region where any one of the average values A1 to A3 is decreased.

[0010] (3) In the swivel chute control step, when satisfying conditions (a) to (d) by increasing any one of the average values A1 to A3, decrease the number of revolutions of the swivel chute charged into the region where any one of the average values A1 to A3 is increased.

[0011] (4) In the swivel chute control step, satisfy conditions (a) to (d) by changing the tilt angle of the swivel chute so that the charging position of the coke changes to the furnace center side or the furnace wall side.

[0012] (5) A blast furnace raw material charging control program for charging ore and coke into a blast furnace from a revolving chute provided at the top of the furnace and depositing the ore layer and the coke layer alternately, which causes a computer to execute a deposition shape specifying process, a layer thickness ratio calculating process, and a revolving chute control process. The deposition shape specifying process specifies 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, which are measured using a surface shape measuring device provided at the top of the furnace. The layer thickness ratio calculating process calculates the 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 uppermost part of the in-furnace deposition layer based on the deposition shapes specified in the deposition shape specifying process. The revolving chute control process controls the tilting angle and / or the number of revolutions of the revolving chute when charging coke so that the distribution of the layer thickness ratios calculated in the layer thickness ratio calculating process satisfies the following conditions (a) to (d) when the distribution 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) Average value A1 < average value A3 < average value A2 However, when the distance from the furnace center in the furnace diameter direction is r (m) and the distance from the furnace center to the furnace wall in the furnace diameter direction is Rt (m), the first region is a region satisfying 0.0 ≦ r / Rt ≦ 0.2, the second region is a region satisfying 0.2 < r / Rt ≦ 0.8, and the third region is a region satisfying 0.8 < r / Rt ≦ 1.0.

[0013] (6) A blast furnace raw material charging control device for charging ore and coke into a blast furnace from a revolving chute provided at the top of the furnace and depositing ore layers and coke layers alternately, comprising a processing unit and a control unit. The processing unit executes a deposition shape identification step and a layer thickness ratio calculation step. The control unit executes a revolving chute control step. The deposition shape identification step 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 deposited in the furnace, measured using a surface shape measuring device provided at the top of the furnace. The layer thickness ratio calculation step calculates the 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 uppermost part of the in-furnace deposition layer based on the deposition shapes identified in the deposition shape identification step. The revolving chute control step controls the tilting angle and / or the number of revolutions of the revolving chute when charging coke so that the distribution of the layer thickness ratio calculated in the layer thickness ratio calculation step satisfies the following conditions (a) to (d) when it does not satisfy the 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) Average value A1 < average value A3 < average value A2 However, when the distance from the furnace center in the furnace diameter direction is r (m) and the distance from the furnace center to the furnace wall in the furnace diameter direction is Rt (m), the first region is a region satisfying 0.0 ≦ r / Rt ≦ 0.2, the second region is a region satisfying 0.2 < r / Rt ≦ 0.8, and the third region is a region satisfying 0.8 < r / Rt ≦ 1.0. [Advantages of the Invention]

[0014] According to the present invention, by controlling the tilting angle and / or the number of revolutions of the revolving chute during coke charging instead of ore charging, the distribution of the layer thickness ratio can be easily adjusted. [Brief Description of the Drawings]

[0015] [Figure 1]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. [Diagram 2] 1 is a flowchart showing a blast furnace raw material charging control method according to the present invention. [Diagram 3] FIG. 2 is a diagram showing the pile shape of one charge of ore layer and coke layer located at the top of the piled up layer in the furnace before application of the blast furnace raw material charging control method according to the present invention (base state). [Figure 4] FIG. 4 is a diagram showing the distribution of layer thickness ratios Lo / (Lc+Lo) in the ore layer and the coke layer in FIG. [Diagram 5] 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. [Figure 6] 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] FIG. 1 is an enlarged view of the upper part of a blast furnace to which a 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 about 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, and each stage is assigned a number (hereinafter, referred to as a notch number). After the rotating chute 2 is rotated once or more 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.

[0017] The ore and coke in one charge may be charged in multiple batches or in one batch. The ore may be sintered ore, pellets, lump ore, or uncalcined carbon-containing agglomerated ore. The ore may 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.

[0018] A surface profile measuring device 10 is provided at the top of the blast furnace 1. The surface profile measuring device 10 measures the shape (surface shape) of the surface S of the ore layer and coke layer charged from the rotating chute 2 and deposited in the furnace. The surface profile measuring device 10 may be a two-dimensional surface profile measuring device (2D profile meter) or a three-dimensional surface profile measuring device (3D profile meter).

[0019] When a two-dimensional surface profile measuring device is used, the surface profile in a specific furnace radial direction is measured in one measurement. For example, if multiple two-dimensional surface profile measuring devices are installed, the surface profiles in multiple furnace radial directions can be measured. The surface profiles measured in multiple furnace radial directions may be used to specify the surface profiles of the unmeasured areas by interpolation, thereby estimating the overall surface profile of the ore layer and the coke layer.

[0020] The three-dimensional surface profile measuring device measures the surface profiles of the ore layer and the coke layer in the furnace radial direction at each predetermined angle in the furnace circumferential direction. The measurement interval of the three-dimensional surface profile measuring device (predetermined angle in the furnace circumferential direction) can be set appropriately. When the measurement interval of the three-dimensional surface profile measuring device is wide, the surface profile of the unmeasured area may be determined by interpolation, as in the case of using the above-mentioned two-dimensional surface profile measuring device.

[0021] 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 the coke layer deposited in the furnace, measured by the surface shape measuring device 10, and identifies the deposition shape of the ore layer and the 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 the 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.

[0022] 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 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 so as 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 of the layer thickness ratio.

[0023] (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 the 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

[0024] Each of the average values ​​A1 to A3 is the arithmetic average value of a plurality of layer thickness ratios Lo / (Lc+Lo) included in each region (first region to third region).

[0025] For conditions (a) to (d), the first region to the third region are regions obtained by partitioning the entire region inside the furnace in the furnace diameter direction in order from the furnace center. Specifically, when the distance from the furnace center in the furnace diameter direction is r (m) and the inner radius of the furnace at the furnace mouth (distance from the furnace center to the furnace wall) is Rt (m), the first region is the region defined by 0.0 ≦ r / Rt ≦ 0.2 (furnace center part), the second region is the region defined by 0.2 < r / Rt ≦ 0.8 (furnace middle part), and the third region is the region defined by 0.8 < r / Rt ≦ 1.0 (furnace wall part). r / Rt is a dimensionless radius [-] indicating the position in the furnace diameter direction.

[0026] By satisfying the above condition (a), the air permeability of the first region (furnace center part) can be increased, and the gas inside the furnace can be stably flowed. By satisfying the above condition (b), the reduction efficiency of the entire furnace can be improved, and it is possible to suppress the deterioration of air permeability locally, the non-uniformity of the gas flow distribution inside the furnace, and the delay of the temperature rise and reduction of the ore. By satisfying the above condition (c), the gas flow velocity at the furnace wall part can be increased, and the growth of zinc and the like attached to the furnace wall can be suppressed. By satisfying the above condition (d), the reduction efficiency of the entire furnace can be improved, and it is possible to suppress the increase in heat loss caused by the average value of the layer thickness ratio Lo / (Lc + Lo) in the third region (furnace wall part) being less than or equal to the average value of the layer thickness ratio Lo / (Lc + Lo) in the first region (furnace center part).

[0027] As a control method of the swivel chute 2 when charging coke, there are a method of controlling the number of revolutions of the swivel chute 2 and a method of controlling the tilt angle (notch) θ of the swivel chute 2.

[0028] By controlling the number of revolutions of the swivel chute 2, the amount of coke deposited near the same coke charging position can be adjusted, so that 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 furnace inner deposition layer.

[0029] 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 the 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 the 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.

[0030] By controlling the tilt angle θ of the rotating chute 2, the coke charging position can be adjusted, and therefore the coke deposition distribution in the furnace radial direction can be adjusted, and the layer thickness ratio Lo / (Lc+Lo) can be adjusted. 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.

[0031] (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 collectively 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.

[0032] (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 furnace center. 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.

[0033] It is to be noted that both the tilt angle θ and the number of revolutions of the swivel chute 2 may be controlled, or only one of them may be controlled.

[0034] <Flowchart of blast furnace raw material charging control method> Fig. 2 is a flow chart of the application of the blast furnace raw material charging control method according to the present embodiment. Referring to Fig. 2, first, the surface shape measuring instrument 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).

[0035] The processor 21 calculates the layer thickness ratio Lo / (Lc+Lo) of the ore layer and the coke layer of one charge located at the top of the deposition layer in the furnace based on the deposition shapes of the ore layer and the coke layer specified in step S102 (step S103). The layer thickness ratio Lo / (Lc+Lo) is calculated in the region from the furnace center to the furnace wall, and the distribution of the layer thickness ratio Lo / (Lc+Lo) in the furnace radial direction is obtained. When the layer thickness ratio Lo / (Lc+Lo) is calculated based on the surface shapes measured in a plurality of furnace radial directions by a two-dimensional surface profiler or a three-dimensional surface profiler, the layer thickness ratio Lo / (Lc+Lo) in each furnace radial direction may be an 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 a representative value. On the other hand, the distribution of the layer thickness ratio Lo / (Lc+Lo) in the radial direction of the furnace 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).

[0036] 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, and therefore will not be described here.

[0037] The above-mentioned steps S102 to S105 can be realized by a program, and 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.

[0038] 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) specially designed and configured for the purpose of the present invention.

[0039] 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 control of the rotating chute 2 (the control of step S105) is performed only when the coke is charged, and the control of the rotating chute 2 (the control of step S105) is not performed when the ore is charged. This makes it possible to more easily adjust the distribution of the layer thickness ratio Lo / (Lc+Lo) compared to Patent Documents 1 and 2. A specific description will be given below.

[0040] 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 against the coke layer (the position where the coke layer collapses) changes, so not only the amount of the coke layer that collapses, but also the position where the coke layer collapses changes. In this case, if the amount and position of the coke layer that collapses are not taken into consideration, it is not possible to adjust the distribution of the layer thickness ratio Lo / (Lc+Lo) so as 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 so as 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 that collapses does not satisfy the conditions (a) to (d).

[0041] On the other hand, in this embodiment, since the ore charging position is not changed by controlling the rotating chute 2, the coke layer collapses due to the collision of the charged ore, but the position where the coke layer collapses does not change. On the premise of this point, if the rotating chute 2 is controlled only during the charging of coke, 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 later, 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. However, any distribution satisfies the conditions (a) to (d). EXAMPLES

[0042] Hereinafter, the blast furnace raw material charging control method according to the present invention will be described in detail 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 the coke layer deposited in the furnace were 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 the coke layer were specified based on the measurement results. In one charge, two batches of ore were charged, and ore O1 (first batch) and ore O2 (second batch) were 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).

[0043] FIG. 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 present invention is applied (base state). In FIG. 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 FIG. 3 indicates the surface of the deposition layer of ore O2 charged before the coke layer C is formed. The deposition shape shown in FIG. 3 is identified based on the measurement results of a surface profile measuring device 10.

[0044] Fig. 4 shows the distribution of layer thickness ratios Lo / (Lc+Lo) in the furnace radial direction in the ore layers O1, O2 and the coke layer C shown in Fig. 3. In Fig. 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 Figs. 5 and 6 are the same as the vertical and horizontal axes in Fig. 4. In Fig. 4, the layer thickness ratio distribution calculated from the measurement results of the surface profiler 10 is shown by a solid line D1, and the target layer thickness ratio distribution is shown by a dashed line D2.

[0045] 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, namely, (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).

[0046] (A) As a method of shifting the notch of the rotating chute 2 in charging the ore, all notches of the ore O1 located on the furnace center side with respect to the notch of the ore O2 were shifted by one notch toward the furnace center side and charged. The ore O2 was charged without changing the notch. Here, the charging of the coke was the same as when forming the coke layer C shown in FIG. 3 without changing the notch. FIG. 5 shows the layer thickness ratio distribution when the method of shifting the notch of the rotating chute 2 during ore charging is applied. The solid line A1 in FIG. 5 shows the layer thickness ratio distribution calculated from the measurement results of the surface shape measuring instrument 10, and the solid line A2 in FIG. 5 shows the layer thickness ratio distribution taking into account the collapse of the coke layer due to the shifting of the notch. The layer thickness ratio distribution A2 was calculated using a burden distribution estimation model (Iron and Steel, 1987, No. 73, No. 1, P91-98). 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.

[0047] 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 position and collapse amount) caused by the charging of the ore is taken into consideration, the layer thickness ratio distribution A2 shown in Fig. 5 is obtained, and since the layer thickness ratio distribution A2 is not very different from the layer thickness ratio distribution D1 shown in Fig. 4, it was found that the layer thickness ratio distribution has not been improved.

[0048] (B) As a method of shifting the notch of the rotating chute 2 in 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 Figure 3, when charging the peripheral coke described above, the coke charging position closest to the furnace center was approximately 0.7 in dimensionless radius r / Rt, so the notch in coke charging was shifted toward the furnace center so that the coke charging position closest to the furnace center was approximately 0.6 in dimensionless radius r / Rt. Here, the notch was not changed for ore charging, and it was the same as when forming the ore layers O1 and O2 shown in Figure 3.

[0049] 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 burden distribution estimation model described above.

[0050] 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 also closer to the target layer thickness ratio distribution D2, and the layer thickness ratio has been improved. [Explanation of symbols]

[0051] 1: Blast furnace 2: Swivel chute 10: Surface shape measuring instrument 20: Control device 21: Processing section 22: Control section

Claims

1. 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) an 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.

2. The blast furnace raw material charging control method according to claim 1, characterized in that, in the rotating chute control step, when conditions (a) to (d) are satisfied by reducing any one of the average values ​​A1 to A3, the number of revolutions of the rotating chute that is charged in an area where any one of the average values ​​A1 to A3 is reduced is increased.

3. The blast furnace raw material charging control method according to claim 1, characterized in that, in the rotating chute control step, 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.

4. A blast furnace raw material charging control method as described in 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.

5. 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) an 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.

6. 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 If 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 rotating chute control step is performed to control the tilt angle and / or the number of revolutions of the rotating chute when charging the coke so as to satisfy the conditions (a) to (d). A blast furnace raw material charging control device characterized by the above. (a) an 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.

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