Operating method of blast furnace, charging method control device, and charging method control program

Abstract

To realize the stable operation of a blast furnace by managing tilt angles of an ore terrace.SOLUTION: In a blast furnace operation method of mutually forming an ore layer and a coke layer in a furnace to tilt the deposition shape at a furnace top downward toward a furnace center side, ore terrace tilt angles of the ore layer formed in the furnace are acquired for each in plural furnace diameter directions, and a representative value determined based on the acquired plural ore terrace tilt angles is used as an operation control index to execute an operation so that the representative value satisfies a standard range.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for operating a blast furnace, a charging method control device, and a charging method control program.

Background Art

[0002] In a blast furnace, an ore layer charging raw material (hereinafter referred to as an ore raw material) for forming an ore layer and a coke layer charging raw material (hereinafter referred to as a coke raw material) for forming a coke layer are alternately charged in a layered manner. The deposition shape of the blast furnace charge has a very large influence on the operation of the blast furnace. Since the charged ore raw material melts in the lower part of the blast furnace, the reducing gas introduced from the tuyere rises in the furnace through the coke layer. In order to stably operate the blast furnace, it is preferable to uniformly distribute the gas in the furnace, and it is required to form a coke layer that can achieve this.

[0003] In a method for operating a blast furnace in which the deposition shape at the furnace top is inclined downward toward the furnace center side, an ore terrace smaller than the angle of repose of the ore is formed in the ore layer near the furnace wall. Patent Document 1 discloses a method for forming an ore terrace in which the ore terrace inclination angle is within the range of ±15 degrees, and the relative distance obtained by dividing the distance from the terrace tip of the charge layer near the furnace top to the furnace wall by the furnace diameter is within the range of 0.1 to 0.6, and the swing chute is controlled.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, Patent Document 1 allows the formation of an ore terrace that slopes downward toward the furnace wall (an ore terrace with a negative ore terrace inclination angle, hereinafter also referred to as a "negative ore terrace"). In the operation method of a blast furnace in which a negative ore terrace is formed, if the positions of the shoulders of the ore terrace and the coke terrace in the radial direction do not match, the thickness of the coke layer in the furnace diameter direction or the furnace circumferential direction will become uneven, and the reduction gas flow will be biased. However, due to the particle size distribution of the ore raw material, wear of the charging chute, etc., the shoulder of the ore terrace may be formed deviated from the intended position. In this case, even if the coke can be charged to the intended position, the thickness of the coke layer laminated in the ore layer in the furnace diameter direction or the furnace circumferential direction becomes uneven, or the flow of the reduction gas is biased, hindering the stable operation of the blast furnace.

[0006] An object of the present invention is to realize stable operation of a blast furnace by appropriately controlling the inclination angle of the ore terrace and suppressing variations in the layer thickness of the coke layer laminated in the ore layer.

Means for Solving the Problems

[0007] In order to solve the above problems, an operation method of a blast furnace according to the present invention is an operation method of a blast furnace in which an ore layer and a coke layer are alternately formed in the furnace and the deposition shape at the furnace top is inclined downward toward the furnace center side. The ore terrace inclination angle of the ore layer formed in the furnace is obtained for each of a plurality of furnace diameter directions, and using the representative value determined based on the plurality of obtained ore terrace inclination angles as an operation management index, the blast furnace is operated so that the representative value satisfies a reference range.

[0008] (2) The operation method of the blast furnace according to (1), wherein the representative value is the minimum value among the plurality of obtained ore terrace inclination angles.

[0009] (3) The operation method of the blast furnace according to (2), wherein the reference range is 0° or more.

[0010] (4) The operation method of the blast furnace according to (2), wherein the reference range is 5° or more.

[0011] (5) Let the total number of notches of the revolving chute provided in the blast furnace be n, the notch number be k, the tilting angle of the revolving chute at the notch number k be θk, the number of revolutions of the revolving chute at the notch number k be Sk, and the total number of revolutions of the revolving chute be T. Then, relationship information, which is the relationship between the first angle calculated based on formula (1) and the second angle which is the ore terrace inclination angle, is obtained in advance. From the relationship information, when the second angle satisfies the reference range, the first angle corresponding to the second angle is obtained, and at least one of the tilting angle of the revolving chute, the number of revolutions of the revolving chute, and the total number of revolutions of the revolving chute is adjusted so as to satisfy the obtained first angle, and the operation is performed. The operation method of the blast furnace according to any one of (2) to (4). JPEG0007701615000001.jpg29138

[0012] (6) The operation method of the blast furnace according to any one of (1) to (5), wherein the ore terrace inclination angle in each furnace diameter direction is calculated based on the deposition shape of the ore layer obtained using a two-dimensional profile meter.

[0013] (7) The operation method of the blast furnace according to any one of (1) to (5), wherein the ore terrace inclination angle in each furnace diameter direction is calculated based on the deposition shape of the ore layer obtained using a three-dimensional profile meter.

[0014] (8) In a charging method control device used for the operation of a blast furnace in which an ore layer and a coke layer are alternately formed in layers in the furnace and the deposition shape at the furnace top is inclined downward toward the furnace center side, an acquisition unit that acquires the ore terrace inclination angle of the ore layer formed in the furnace for each of a plurality of furnace diameter directions, and an operation control unit that operates so that a representative value determined based on the plurality of ore terrace inclination angles acquired by the acquisition unit satisfies a reference range, with the representative value as an operation management index.

[0015] (9) In a charging method control program used for the operation of a blast furnace in which an ore layer and a coke layer are alternately formed in layers in the furnace and the deposition shape at the furnace top is inclined downward toward the furnace center side, an acquisition step of acquiring the ore terrace inclination angle of the ore layer formed in the furnace for each of a plurality of furnace diameter directions, and an operation step of operating so that the representative value determined based on the plurality of ore terrace inclination angles acquired in the acquisition step satisfies a reference range, with the representative value as an operation management index. A charging method control program for causing a process computer to execute.

Effect of the Invention

[0016] According to the present invention, the generation of negative ore terraces can be suppressed. As a result, the layer thickness of the coke layer laminated on the ore layer is appropriately managed, so that stable operation of the blast furnace can be realized.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiment for Carrying Out the Invention

[0018] Figure 1 is a schematic view of a blast furnace used in the operation method of a blast furnace according to an embodiment of the present invention. The blast furnace 1 is a bell-less blast furnace and includes a tuyere 2, an annular pipe 3, a blow pipe 4, a pulverized coal injection lance 5, a revolving chute 6, a profile meter 7, and a controller 8. A plurality of tuyeres 2 are provided at the lower part of the furnace along the circumferential direction of the blast furnace 1. The annular pipe 3 is arranged so as to surround the lower part of the blast furnace 1. The blow pipes 4 are intermittently provided in the circumferential direction of the annular pipe 3, and each is connected to a different tuyere 2. The pulverized coal injection lance 5 passes through each blow pipe 4, and the tip of the pulverized coal injection lance 5 extends into the interior of each blow pipe 4.

[0019] The revolving chute 6 rotates around an axis extending in the vertical direction and alternately charges the ore raw material and the coke raw material. The ore raw material and the coke raw material may each be charged in a plurality of times or each may be charged once. An ore layer and a coke layer are alternately formed in the furnace. The raw material charging performed to form one ore layer is defined as ore charge, and achieving this ore charge by one raw material charging is defined as "one-dump charging", and achieving this ore charge by a plurality of raw material chargings is defined as "multiple-dump charging".

[0020] Sintered ore, pellets, lump ore, and uncalcined carbonaceous lump ore can be used as the ore raw material. Further, the ore raw material may contain something other than ore (for example, a reduction aid such as small lump coke). The coke raw material may contain ferrocoke in addition to coke. The driving method of the revolving chute 6 may be any of forward tilting, reverse tilting, and a combination of forward tilting and reverse tilting. Note that forward tilting means a driving method of driving the revolving chute 6 from the furnace wall side toward the furnace center side.

[0021] The profile meter 7 acquires the deposition shapes of the ore layer and the coke layer. Specifically, the profile meter 7 acquires the waveform of the distance between the profile meter 7 and the surface of the ore layer (or coke layer) for each measurement point. FIG. 2 is an enlarged view in the vicinity of the furnace wall of the coke layer and the ore layer deposited on the uppermost part of the in-furnace deposition layer. Referring to FIG. 2, an ore terrace indicated by reference sign T that is inclined at an inclination angle θ with respect to the horizontal plane in the furnace diameter direction (indicated by a broken line in the figure) is formed on the furnace wall side of the ore layer. The inclination angle θ of this ore terrace is smaller than the angle of repose of the ore. By controlling the swivel chute 6, the magnitude of the inclination angle θ can be changed to adjust the layer thickness of the coke deposited on the ore terrace. The magnitude of the inclination angle θ is calculated by a controller 8 described later.

[0022] As the profile meter 7, a two-dimensional profile meter or a three-dimensional profile meter can be used. In the case of a two-dimensional profile meter, the deposition shape in a specific furnace diameter direction is acquired by one measurement. Therefore, by installing a plurality of two-dimensional profile meters, the deposition shapes of the ore layer in a plurality of furnace diameter directions can be acquired. Further, by providing a traveling mechanism for traveling the two-dimensional profile meter in the furnace circumferential direction, the deposition shapes of the ore layer in a plurality of furnace diameter directions can be acquired by one two-dimensional profile meter. In addition, when using a two-dimensional profile meter, the deposition shape of the ore layer may be estimated by interpolating the deposition shapes in the unmeasured regions using the deposition shapes acquired for a plurality of furnace diameter directions.

[0023] The three-dimensional profile meter acquires the deposition shape of the ore layer in the furnace diameter direction at predetermined angles in the furnace circumferential direction. The measurement interval (predetermined angle) of the three-dimensional profile meter can be set as appropriate. When the measurement interval of the three-dimensional profile meter is wide, interpolation processing for interpolating the deposition shape of the unmeasured area may be performed in the same manner as when using the above-described two-dimensional profile meter. Further, the measurement data of the three-dimensional profile meter is not limited to being acquired according to the furnace circumferential direction angle. For example, it may be measured at grid-like measurement points. In this case, it can be processed into measurement data of the furnace circumferential direction angle and then used in subsequent processes.

[0024] Here, the acquisition of the deposition shape includes not only receiving raw measurement data from the profile meter 7 but also appropriately processing (for example, interpolating) the raw data to obtain it.

[0025] The controller 8 calculates the inclination angle θ of the ore terrace for each measurement azimuth based on the deposition shape of the ore layer acquired by the profile meter 7, and obtains the minimum value among the calculated inclination angles θ of each ore terrace. The minimum value of this ore terrace inclination angle θ can be used as a "representative value" described later.

[0026] The processing performed by the controller 8 can be realized by a program. A program prepared in advance for realizing various processes is stored in the auxiliary storage device, and a process computer such as a CPU reads the program stored in the auxiliary storage device into the main storage device, and the process computer executes the program read into the main storage device, thereby realizing it.

[0027] Further, the above program can also be provided to a process computer (e.g., a server) in a state recorded on a computer-readable recording medium. Examples of computer-readable recording media include optical discs such as CD-ROMs, phase change optical discs such as DVD-ROMs, magneto-optical discs such as MO (MagnetOptical) and MD (Mini Disk), magnetic discs such as floppy (registered trademark) discs and removable hard discs, and memory cards such as compact flash (registered trademark), smart media, SD memory cards, and memory sticks. Also included as a recording medium are hardware devices such as integrated circuits (IC chips, etc.) specially designed and configured for the purpose of the present invention.

[0028] The inventors of the present invention have discovered that by operating a blast furnace so that the inclination angle θ of the ore terrace is 0° or more, the bias of the reducing gas is suppressed and stable operation of the blast furnace is realized. That is, when the inclination angle θ of the ore terrace is less than 0°, as described above, the variation in the thickness of the coke layer laminated on the ore layer in the furnace diameter direction or the furnace circumference direction becomes large, and the stable operation of the blast furnace is inhibited. Therefore, by obtaining the ore terrace inclination angle θ for each of a plurality of furnace diameter directions and performing operation management so that the minimum value of these ore terrace inclination angles θ is used as a representative value and the representative value is 0° or more (reference range), stable operation of the blast furnace can be realized. When using "whether or not the minimum value of the ore terrace inclination angle θ is 0° or more" as an operation management index, the measurement interval (predetermined interval) of the three-dimensional profile meter is preferably set to 45° or less, for example.

[0029] Here, the "plural furnace radial directions" refer to virtual lines extending from the furnace center towards the furnace wall. On the furnace diameter, there are a first furnace radial direction extending from the furnace center towards the furnace wall and a second furnace radial direction extending from the furnace center towards the furnace wall with a direction 180 degrees different from that of the first furnace radial direction. In this specification, these two furnace radial directions existing on the furnace diameter are each treated as independent furnace radial directions. Therefore, obtaining the ore terrace inclination angle for each of the directions of the first furnace radial direction and the second furnace radial direction arranged on the furnace diameter is also included in the above-mentioned "obtaining the inclination angle θ of the ore terrace for each of the plural furnace radial directions".

[0030] The controller 8 can compare the ore terrace inclination angles θ in each furnace radial direction with each other and use the minimum value as a representative value. By using the minimum value of the ore terrace inclination angle θ as the representative value, the smallest ore terrace inclination angle θ among the data obtained in each furnace radial direction is improved to 0° or more, so that the entire furnace circumferential direction can be shifted towards an appropriate range. As a result, the above-mentioned effect (uniform distribution of gas) can be enhanced. In addition, an action may be further implemented so that the ore terrace inclination angles θ in each furnace radial direction become uniform to enhance the uniformity of gas distribution.

[0031] Here, when the measurement interval of the ore terrace inclination angle θ is wide, there is a risk of overlooking a negative ore terrace. For example, even if all the ore terrace inclination angles θ measured at 90° intervals are 0° or more, there may be a negative ore terrace between these measurement positions. In this case, the variation in the thickness of the coke layer laminated on the ore layer in the furnace radial direction or the furnace circumferential direction becomes large, and there is a risk of hindering the stable operation of the blast furnace. Therefore, the present inventors examined an operation method applicable even when the measurement interval of the ore terrace inclination angle θ is wide as follows.

[0032] Table 1 is from 4000 to 5000 m 3This shows the relationship between σ blast pressure (hPa) and permeability index (-), which are examples of "indicators for evaluating the stability of blast furnace operation" obtained based on multiple operating records from an actual reactor of a certain grade, and the ore terrace inclination angle (°). The results of operation numbers 1 to 7 shown in Table 1 were all measured and calculated at a specific azimuth inside the furnace. Table 1 also shows the inclination angle (°) of the coke terrace formed on the ore terrace.

[0033]

Table 1

[0034] σ blast pressure (hPa) and permeability index (-) are indicators showing the quality of the blast furnace operation status. When σ blast pressure (hPa) and permeability index (-) are low, it can be considered that stable operation is achieved. σ blast pressure (hPa) is the standard deviation in the time-series change of the blast pressure. The blast pressure refers to the pressure of the hot blast measured in front of the annular pipe 3. The permeability index (-) is the in-furnace ventilation resistance index (K), and can be calculated, for example, by the following formula (A).

Equation

[0035] For example, in the above operating results, it can be considered that the σ blowing pressure (hPa) being 26 (hPa) or less and the air permeability index (-) being 2.5 (-) or less are taken as one criterion for stable operation (hereinafter also referred to as "stable operation conditions"). That is, when the σ blowing pressure (hPa) is 26 (hPa) or less and the air permeability index (-) is 2.5 (-) or less, it can be considered that the reducing gas in the furnace is appropriately distributed and the ore raw material is uniformly reduced in the furnace diameter direction. When it is not stable operation, since there is a bias in the flow of the reducing gas, it can be considered that the σ blowing pressure (hPa) exceeds 26 (hPa) and the air permeability index (-) exceeds 2.5 (-). Therefore, in the example of Table 1, the "stable operation conditions" can be set to "σ blowing pressure: 26 (hPa)" and "air permeability index: 2.5 (-)". Based on Table 1, the minimum value of the ore terrace inclination angle θ when the σ blowing pressure is 26 (hPa) or less and the air permeability index is 2.5 (-) or less is more than 4°.

[0036] Here, the inventors considered, by means of a cold model test using a 1 / 3 bell-less test apparatus, the reason why the stable operation conditions were not satisfied in operation numbers 5 to 7 in Table 1 despite the ore terrace inclination angle θ being 2° to 4° (values of 0° or more). The 1 / 3 bell-less test apparatus is a model experimental apparatus (with a radius of about 1800 mm) of 1 / 3 size of an actual furnace that simulates a bell-less type top charging device. It was found by the cold model test that there is a standard deviation of about 2° in the ore terrace inclination angle in the furnace circumferential direction and a variation of up to about 4°. From the above experimental results, if the blast furnace is operated so that the minimum value of the obtained ore terrace inclination angle θ is 5° or more, even if the measurement interval of the ore terrace inclination angle θ is hypothetically widened, the possibility of overlooking the negative ore terrace is low, and thus the stable operation of the blast furnace can be realized more effectively.

[0037] In addition, the upper limit value of the reference range of the ore terrace inclination angle θ is not particularly limited, but can be appropriately set based on the angle of repose of the ore. For example, when the angle of repose of the ore is 27°, the upper limit value of the reference range of the ore terrace inclination angle θ can be set to 26° or less. Note that the angle of repose of the ore varies depending on the contained components of the ore and the like.

[0038] When the minimum value of the ore terrace inclination angle θ does not satisfy the reference range, the controller 8 implements an improvement action to improve this. The controller 8 can implement any one of the following improvement actions 1 to 3. However, these improvement actions 1 to 3 are examples, and the present invention is not limited thereto.

[0039] (Improvement Action 1) In the ore dump, shift all the notches by one notch toward the furnace wall side and change to external vibration. By shifting all the notches by one notch toward the furnace wall side, the ore raw material is charged into a region closer to the furnace wall, so that the ore terrace inclination angle θ can be increased.

[0040] (Improvement Action 2) Lower the stock line of the blast furnace. By lowering the stock line, the amount of ore raw material charged to the furnace wall side increases, so that the ore terrace inclination angle θ can be increased.

[0041] (Improvement Action 3) Improvement Action 3 consists of the following (A) to (C). (A) Obtain in advance the relationship (hereinafter also referred to as relationship information) between the first angle calculated based on the following formula (1) and the second angle which is the ore terrace inclination angle. The relationship information may be obtained based on operation results, or may be obtained based on the test results of an experimental device (for example, the aforementioned 1 / 3 bell-less test device). (B) From the relationship information, obtain the first angle corresponding to the second angle when the second angle satisfies the reference range (in the above-described embodiment, 0° or more or 5° or more). The operation is carried out by adjusting at least one of the tilting angle of the swivel chute, the number of revolutions of the swivel chute, and the total number of revolutions of the swivel chute so as to satisfy the first angle obtained in (C)(B). Here, in Equation (1), let n be the total number of notches of the swivel chute provided in the blast furnace, k be the notch number, θk be the tilting angle of the swivel chute at the notch number k, Sk be the number of revolutions of the swivel chute at the notch number k, and T be the total number of revolutions of the swivel chute.

[0042]

Equation

[0043] The notch number is a numerical value obtained by numbering the preset tilting angles of the swivel chute 6, and it means that the larger the numerical value of the notch number k, the more the charged raw materials are charged toward the furnace center side, and the smaller the numerical value, the more they are charged toward the furnace wall side. An example of the notch number k and the number of revolutions Sk is shown.

Table 2

[0044] By operating the blast furnace as described above, the amount of ore raw materials charged to the furnace wall side increases, so the ore terrace inclination angle θ can be increased.

[0045] In this embodiment, a bell-less blast furnace is taken as an example for explanation, but the present invention can also be applied to a bell blast furnace. In the case of a bell blast furnace, by adjusting the angle of the movable armor that collides with the ore raw materials falling in the furnace and corrects the falling trajectory, or by adjusting the opening speed of the bell, an improvement action can be taken.

[0046] After the improvement action, it is determined again whether the minimum value of the ore terrace inclination angle θ satisfies the reference range. As a result, if the minimum value of the ore terrace inclination angle θ does not satisfy the reference range, a further improvement action is taken. That is, the improvement action is repeatedly carried out until the minimum value of the ore terrace inclination angle θ satisfies the reference range.

[0047] According to another aspect, the present invention is realized by the charging method control device shown in FIG. 3. The charging method control device 10 includes an acquisition unit 11 and an operation control unit 12. The acquisition unit 11 acquires the ore terrace inclination angle of the ore layer formed in the furnace for each of a plurality of furnace radial directions. That is, the acquisition unit 11 acquires the deposition shape of the ore layer and calculates the ore terrace inclination angle in each furnace radial direction. The acquisition unit 11 is realized by the cooperation of the profile meter 7 and the controller 8. The operation control unit 12 operates such that the minimum value (representative value) among the plurality of ore terrace inclination angles acquired by the acquisition unit 11 is used as an operation management index and this minimum value satisfies the reference range. The operation control unit 12 is realized by the controller 8. Since the details of the processing have been described above, the description will not be repeated.

[0048] FIG. 4 is a flowchart showing the processing realized by the above-described program. Since the description would be repetitive, only the outline of the processing will be described. The acquisition unit 11 (profile meter 7) acquires the deposition shape of the ore layer (step S101). The acquisition unit 11 (controller 8) calculates the ore terrace inclination angle θ for each furnace radial direction based on the acquired deposition shape (step S102). The operation control unit 12 (controller 8) determines the minimum value of the calculated plurality of ore terrace inclination angles as the representative value (step S103). The operation control unit 12 (controller 8) determines whether the determined representative value satisfies the reference range (step S104). If the representative value satisfies the reference range (step S104 Yes), the processing ends. If the representative value does not satisfy the reference range (step S104 No), the processing proceeds to step S105. In step S105, the operation control unit 12 (controller 8) executes the above-described action, and the processing returns to step S101. Note that steps S101 to S102 correspond to the "acquisition step" described in claim 9, and steps S103 to S105 correspond to the "operation step" described in claim 9.

Example

[0049] Examples will be shown and the operation method of the blast furnace of the present invention will be described in detail. Using a 1 / 3 bell-less test apparatus, blast furnace raw materials were charged in layers under the same conditions as an actual blast furnace, and the ore terrace inclination angles (°) in a plurality of furnace diameter directions were examined. Since the 1 / 3 bell-less test apparatus has been described above, the description will not be repeated. The average particle size of the blast furnace raw materials was set to about 1 / 3 of that of the actual furnace, and the charging amount was set to about 1 / 27 of that of the actual furnace. Coke charging was carried out at 1 dump per charge, and the charging amount per charge of coke was set to about 1.3 t. Also, ore charging was carried out at 1 dump per charge, and the charging amount per charge of ore was set to about 7.3 t.

[0050] The deposition shape of the ore layer was measured with a 3D profile meter, and this measured 3D deposition shape was cut out at 10° intervals in the furnace circumferential direction to obtain the deposition shape in each azimuth (corresponding to the furnace diameter direction). After obtaining the deposition shape in each azimuth, the ore terrace inclination angle (°) in each azimuth was calculated. The representative value was taken as the minimum value of the ore terrace inclination angle (°). In FIG. 5, the ore terrace inclination angles (°) before and after the implementation of the improvement action in each azimuth were plotted. In this example, the above-described improvement action 3 was implemented.

[0051] Before the implementation of the improvement action, as shown by the white-plotted (circular marks) in FIG. 5, the minimum value of the ore terrace inclination angle was -1°. At this time, the first angle calculated by the above formula (1) was 47°. Therefore, in order to make it 5° or more, from the relationship between the first angle and the second angle (corresponding to the "relationship information"), when the second angle satisfies the reference range, the first angle = 50° corresponding to the second angle (5°) was obtained, and based on the formula (1) that satisfies this first angle (50°), the inclination angle θ of the swivel chute was adjusted to simulate the improvement action 3.

[0052] As a result, as shown by the black-plotted (circular marks) in FIG. 5, the minimum value of the ore terrace inclination angle became 5° (shown by the broken line) or more. That is, in all directions, the ore terrace inclination angle satisfied the reference range.

[0053] Based on the results obtained by the 1 / 3 bell-less test apparatus, in the actual furnace, an operation with the ore dump changed was carried out to examine whether the operation would be stable. The target blast furnace was a blast furnace of 4000 - 5000 m 3 class, and it was operating under the same charging conditions as before the implementation of the improvement actions in the above 1 / 3 bell-less test. At this time, since the minimum value of the ore terrace inclination angle was below the reference range (5°), improvement action 3 was implemented by adjusting the inclination angle θ of the swivel chute based on formula (1) that satisfies the first angle = 50°. As a result, since the fluctuation of the blowing pressure throughout the furnace decreased by 10% and the ventilation resistance also decreased by 2%, it was confirmed that the gas flow in the furnace was homogenized and stable operation became possible.

Explanation of symbols

[0054] 1 Blast furnace 2 Tuyere 3 Annular pipe 4 Blower pipe 5 Lance for injecting pulverized coal 6 Swivel chute 7 Profile meter 8 Controller 10 Charging method control device 11 Acquisition unit 12 Operation control unit

Claims

1. In a method for operating a blast furnace in which an ore layer and a coke layer are alternately formed in the furnace and the deposition shape at the furnace top is inclined downward toward the furnace center side, obtain the ore terrace inclination angles of the ore layer formed in the furnace for each of a plurality of furnace diameter directions, using, as an operation management index, a representative value determined based on the plurality of obtained ore terrace inclination angles, operate so that the representative value satisfies a reference range, wherein the representative value is the minimum value among the plurality of obtained ore terrace inclination angles, and the reference range is 0° or more A method for operating a blast furnace, characterized by the above.

2. The method for operating a blast furnace according to claim 1, wherein the reference range is 5° or more.

3. Let the total number of notches of the swivel chute provided in the blast furnace be n, the notch number be k, the tilting angle of the swivel chute at the notch number k be θk, the number of revolutions of the swivel chute at the notch number k be Sk, and the total number of revolutions of the swivel chute be T. Then, obtain in advance relationship information that is the relationship between a first angle calculated based on formula (1) and a second angle that is the ore terrace inclination angle, from the relationship information, obtain the first angle corresponding to the second angle when the second angle satisfies the reference range, and operate by adjusting at least one of the tilting angle of the swivel chute, the number of revolutions of the swivel chute, and the total number of revolutions of the swivel chute so as to satisfy the obtained first angle. The method for operating a blast furnace according to claim 1 or 2.

4. The method for operating a blast furnace according to any one of claims 1 to 3, characterized in that the ore terrace inclination angle in each furnace diameter direction is calculated based on the deposition shape of the ore layer obtained using a two-dimensional profile meter.

5. The method for operating a blast furnace according to any one of claims 1 to 3, characterized in that the ore terrace inclination angle in each furnace diameter direction is calculated based on the deposition shape of the ore layer obtained using a three-dimensional profile meter.

6. In a charging method control device used for operating a blast furnace in which an ore layer and a coke layer are alternately formed in a layered manner in the furnace and the deposition shape at the furnace top is inclined downward toward the furnace center side, an acquisition unit that acquires the ore terrace inclination angles of the ore layer formed in the furnace for each of a plurality of furnace diameter directions, an operation control unit that uses, as an operation management index, a representative value determined based on the plurality of ore terrace inclination angles acquired by the acquisition unit and operates so that the representative value satisfies a reference range, and having The representative value is the minimum value among the plurality of ore terrace inclination angles acquired by the acquisition unit, and the reference range is 0° or more characterized by the charging method control device.

7. In a charging method control program used for the operation of a blast furnace in which an ore layer and a coke layer are alternately formed in layers in the furnace and the deposition shape at the furnace top is inclined downward toward the furnace center side, an acquisition step of acquiring the ore terrace inclination angle of the ore layer formed in the furnace for each of a plurality of furnace diameters; an operation step of operating so that the representative value satisfies a reference range, with the representative value determined based on the plurality of ore terrace inclination angles acquired in the acquisition step as an operation management index; a charging method control program for causing a process computer to execute, the representative value is the minimum value among the plurality of ore terrace inclination angles acquired in the acquisition step, and the reference range is 0° or more characterized by the charging method control program.

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