JP7640855B2 - Blast furnace raw material charging decision method, charging method decision device, and charging method decision program - Google Patents

Description

The present invention relates to a charging method, a charging method determination device, and a charging method determination program for determining the method of charging blast furnace raw materials into a bell-less type blast furnace having a rotating chute.

For stable operation of a blast furnace, it is necessary to stabilize the gas flow inside the furnace. When blast furnace raw materials are charged into the blast furnace by rotating the chute, if there is variation in the amount of blast furnace raw materials charged in the circumferential direction of the furnace, this will result in variation in the gas flow in the circumferential direction of the furnace. Therefore, in Patent Document 1, the position at which the charging of the blast furnace raw materials begins (charging start position) is shifted a predetermined amount in the circumferential direction (furnace circumferential direction) for each charge of blast furnace raw materials.

JP 2000-336411 A JP 2018-48361 A Japanese Unexamined Patent Publication No. 8-188806 Japanese Unexamined Patent Publication No. 58-123808 Japanese Unexamined Patent Publication No. 6-10018 Patent No. 3948162

However, simply shifting the charging start position in the furnace circumferential direction, as in Patent Document 1, may not reduce the variation in the amount of blast furnace raw materials charged in the furnace circumferential direction, as will be described later.

According to the invention described in Patent Document 1, if the number of revolutions of the chute is the same each time blast furnace raw materials are charged, it may be possible to reduce the variation in the amount of charging in the circumferential direction of the furnace by shifting the charging start position in the circumferential direction of the furnace. However, in actual charging, the number of revolutions of the chute from the start to the end of charging of the blast furnace raw materials varies depending on the properties (grain size composition) of the blast furnace raw materials.

For example, when charging raw materials for a blast furnace into a blast furnace, a certain weight of raw materials is stored in a hopper, and then the raw materials are supplied from the hopper to a chute. However, if the particle size composition (bulk density) of the raw materials for a blast furnace differs, the time it takes to supply the raw materials from the hopper to the chute differs, and so the time it takes from start to finish charging the raw materials for a blast furnace differs. For example, the coarser the raw materials for a blast furnace are, the longer it takes to charge them, and the finer the raw materials are, the shorter the charging time. As a result, there is variation in the number of revolutions of the chute from start to finish of charging the raw materials for a blast furnace.

As described above, if there is variation in the number of revolutions of the chute, even if the charging start position is shifted in the circumferential direction of the furnace, the blast furnace raw materials cannot be charged as expected, making it difficult to reduce the variation in the charging amount in the circumferential direction.

The first invention of this application is a method for determining the charging of blast furnace raw materials, which determines the method for charging blast furnace raw materials into a bell-less blast furnace by rotating a rotating chute. First, when the same type of blast furnace raw materials is charged again after being charged multiple times, a parameter related to the number of occurrences of areas in which the amount of blast furnace raw materials charged in the circumferential direction of the furnace is relatively large is calculated for each position in the circumferential direction of the furnace for all combinations of multiple predetermined charging start positions and rotation directions of the rotating chute. This parameter is calculated from the charging start position and rotation direction, and the rotation number error, which indicates the deviation of the actual number of rotations from the set number of rotations of the rotating chute.

Next, for all combinations, the variation of the parameters is calculated based on the distribution of the parameters according to the position in the furnace circumferential direction. The charging start position when the minimum variation is obtained is then determined as the charging start position when the same type of blast furnace raw material is charged again. In addition, the rotation direction when the minimum variation is obtained is determined as the rotation direction of the rotating chute when the same type of blast furnace raw material is charged again.

The above-mentioned variation can be the standard deviation of a parameter. The parameter can be the ratio of the number of occurrences to the number of times the blast furnace raw materials are charged.

When calculating parameters for each position in the furnace circumferential direction, the rotation number error can be determined from the rotation number error in past blast furnace raw material charging. Rotation number errors include cases where the actual rotation number is more than the set rotation number, and the blast furnace raw material is charged after the final rotation exceeds one circumferential rotation, and cases where the actual rotation number is less than the set rotation number, and the blast furnace raw material is charged before the final rotation reaches one circumferential rotation.

The second invention of the present application is a device for determining the method of charging raw materials into a blast furnace by rotating a rotating chute, and has a calculation unit and a determination unit.

When the same type of blast furnace raw materials is charged again after being charged multiple times, the calculation unit calculates, for each position in the circumferential direction of the furnace, a parameter related to the number of occurrences of areas in which the amount of blast furnace raw materials charged is relatively large in the circumferential direction of the furnace for all combinations of multiple predetermined charging start positions and rotation directions of the rotating chute. This parameter is calculated from the charging start position and rotation direction, and the rotation number error indicating the deviation of the actual number of rotations from the set number of rotations of the rotating chute. The calculation unit then calculates the variation of the parameter for all combinations based on the distribution of the parameter according to the position in the circumferential direction of the furnace.

The determination unit determines the charging start position when the minimum variation is obtained as the charging start position when the same type of blast furnace raw materials is charged again. The determination unit also determines the rotation direction when the minimum variation is obtained as the rotation direction of the rotating chute when the same type of blast furnace raw materials is charged again.

The third invention of this application is a program that causes a computer to execute the following steps to determine a method for charging blast furnace raw materials into a bell-less blast furnace by rotating a rotating chute. In this step, when the same type of blast furnace raw materials is charged again after being charged multiple times, a parameter related to the number of occurrences of areas in which the amount of blast furnace raw materials charged in the circumferential direction of the furnace is relatively large is calculated for each position in the circumferential direction of the furnace for all combinations of multiple predetermined charging start positions and rotation directions of the rotating chute. This parameter is calculated from the charging start position and rotation direction, and the rotation number error that indicates the deviation of the actual number of rotations from the set number of rotations of the rotating chute.

Next, for all combinations, the variation of the parameters is calculated based on the distribution of the parameters according to the position in the furnace circumferential direction. The charging start position when the minimum variation is obtained is determined as the charging start position when the same type of blast furnace raw materials is charged again. In addition, the rotation direction when the minimum variation is obtained is determined as the rotation direction of the rotating chute when the same type of blast furnace raw materials is charged again.

According to the present invention, it is possible to reduce the variation in the amount of blast furnace raw materials charged in the furnace circumferential direction.

FIG. 2 is a diagram showing a part of the internal structure of a blast furnace. FIG. 2 is a diagram illustrating the starting position of charging blast furnace raw materials. FIG. 13 is a diagram illustrating the charging state of the final rotation of blast furnace raw materials when the rotation number error is a negative value. FIG. 13 is a diagram illustrating the charging state of the final rotation of blast furnace raw materials when the rotation number error is a positive value. 1 is a flowchart showing a process for determining a method for charging blast furnace raw materials. FIG. 2 is a block diagram showing a configuration of a charging method determination device. FIG. 13 is a diagram showing the distribution of the ratio R after charging of coke (after 6 charges). FIG. 13 shows the distribution of ratio R after ore charging (after 6 charges). FIG. 1 is a diagram showing the distribution of ratio R in the examples and comparative examples with respect to coke charging. FIG. 1 is a diagram showing the distribution of ratio R in the examples and comparative examples with respect to the charging of ore.

(Internal structure of a blast furnace)
In the method for charging raw materials into a blast furnace according to the present embodiment, a bell-less blast furnace (hereinafter, simply referred to as a "blast furnace") is used. The internal structure of the blast furnace will be described with reference to Fig. 1. Fig. 1 shows the internal structure of a portion (top) of the blast furnace.

At the top of the blast furnace 1, a chute 2 (rotating chute) is provided, which rotates around a rotation axis RA as shown by arrow D1 or arrow D2. The directions shown by arrows D1 and D2 are opposite to each other. The rotation axis RA coincides with the center of the furnace. When the chute 2 rotates, the blast furnace raw materials (coke and ore) supplied to the chute 2 from a hopper (not shown) fall from the tip of the chute 2 and are deposited inside the blast furnace 1 (i.e., the furnace wall 3).

Because coke and ore are charged from the chute 2, coke layers CL and ore layers OL are formed alternately inside the blast furnace 1 (i.e., furnace wall 3). Note that one charging of blast furnace raw materials (supplying a predetermined weight of blast furnace raw materials from a hopper to the chute 2 and charging it into the blast furnace 1) is called a dump, and the repeated unit of charging of blast furnace raw materials is called a charge. When forming the coke layer CL, coke is charged by one or more dumps, and when forming the ore layer OL, ore is charged by one or more dumps.

When blast furnace raw materials are charged into the blast furnace 1, the chute 2 rotates around the rotation axis RA and changes the angle θ at which the chute 2 is tilted relative to the rotation axis RA (called the tilt angle).

When charging blast furnace raw materials into the blast furnace 1, the position at which charging of the blast furnace raw materials begins (hereinafter referred to as the "charging start position") and the direction in which the chute 2 is rotated (hereinafter referred to as the "rotation direction") are determined.

The charging start position is a position in the circumferential direction of the blast furnace 1, and is defined by an angle (0 to 360 degrees) when one circumference in the circumferential direction is 360 degrees. In this embodiment, the charging start position when charging blast furnace raw materials is determined from a plurality of predetermined charging start positions. For example, as shown in FIG. 2, four charging start positions, 0 degrees, 90 degrees, 270 degrees, and 360 degrees, can be determined in advance. FIG. 2 shows a plane perpendicular to the furnace height direction in the blast furnace 1.

The charging start positions are not limited to the four positions shown in Figure 2, and any number of charging start positions can be determined. Also, in Figure 2, the charging start positions are set at equal intervals in the furnace circumferential direction, but the charging start positions can also be set at different intervals in the furnace circumferential direction.

The charging start position can be based on the position of the chute 2 in the furnace circumferential direction, or on the position where the blast furnace raw materials dropped from the chute 2 land in the blast furnace 1. The position where the blast furnace raw materials land can be determined, for example, based on a simulation using the Discrete Element Method (publicly known literature, ISIJ International, Vol. 57, pp. 272-278). Note that the actual landing position of the blast furnace raw materials does not need to completely match the landing position determined by the simulation.

In this embodiment, the rotation direction is the rotation direction of the chute 2 when viewed from the top of the blast furnace 1 (the direction of the arrow D3 shown in FIG. 1). Here, when the chute 2 rotates clockwise, the rotation direction is the "right direction", and when the chute 2 rotates counterclockwise, the rotation direction is the "left direction". Note that the rotation direction of the chute 2 can also be specified when viewed from the lower part of the blast furnace 1. The rotation direction in this case is the opposite of the rotation direction of the chute 2 when viewed from the top of the blast furnace 1.

(Turning number error Er)
When the chute 2 is rotated to charge the blast furnace raw materials into the blast furnace 1, the number of revolutions of the chute 2 is preset, but there may be a discrepancy between the number of revolutions N that is preset (hereinafter referred to as the "set number of revolutions") and the number of revolutions when the blast furnace raw materials are actually charged (hereinafter referred to as the "actual number of revolutions"). This discrepancy is called the number of revolutions error Er, and the number of revolutions error Er is expressed by the following formula (1).

In the above formula (1), Er is the rotation error [rotations], tm is the time from the start of actual charging of blast furnace raw materials to the end of charging (hereinafter referred to as "actual charging time") [sec], N is the set rotation number [rotations], and tr is the time it takes for the chute 2 to rotate one revolution (360 [deg]) [sec]. The value of "N x tr" is the time it takes to charge the blast furnace raw materials by rotating the chute 2 the set number of rotations N (hereinafter referred to as "planned charging time").

According to the above formula (1), when raw materials for the blast furnace are charged beyond the set number of rotations N, the actual charging time tm is longer than the scheduled charging time (N x tr), so the rotation number error Er is a positive value [rotations]. On the other hand, when raw materials for the blast furnace are charged before the set number of rotations N is reached, the actual charging time tm is shorter than the scheduled charging time (N x tr), so the rotation number error Er is a negative value [rotations].

In this embodiment, the actual charging time tm is measured and converted into the rotation number error Er based on this actual charging time tm. Here, since the rotation speed of the chute 2 is constant, the actual charging time tm can be converted into the rotation number error Er based on the relationship between the time tr and the rotation angle of 360 [deg].

Time tr is a fixed time that can be measured in advance or calculated from the set rotation speed [rpm] of the chute 2. As described above, the actual charging time tm is the time from when the actual charging of blast furnace raw materials starts to when charging ends, and there are various methods for measuring the actual charging time tm. Below, two examples of methods for measuring the actual charging time tm are given.

In the first measurement method, a load cell is first installed in a hopper (not shown) that contains the blast furnace raw materials. The hopper referred to here is the hopper located closest to the chute 2 in the supply path of the blast furnace raw materials.

For example, if hoppers are arranged in two tiers, upper and lower, and blast furnace raw materials are supplied from the upper hopper to the lower hopper and from the lower hopper to chute 2, the lower hopper will be the hopper closest to chute 2. Also, if blast furnace raw materials are supplied from multiple hoppers arranged in parallel horizontally to a collecting hopper, and then from the collecting hopper to chute 2, the collecting hopper will be the hopper closest to chute 2. Here, in a structure in which the blast furnace raw materials simply pass through the collecting hopper, a load cell can be provided in the collecting hopper or the parallel hoppers. Furthermore, if blast furnace raw materials are supplied to chute 2 from multiple hoppers arranged in parallel horizontally, each of the multiple hoppers arranged in parallel will be the hopper closest to chute 2.

When the gate of the hopper is opened (i.e., when the charging of the blast furnace raw materials begins), the timer starts measuring the actual charging time tm. Then, when the load cell detects that there is no more blast furnace raw materials in the hopper (i.e., the weight of the blast furnace raw materials becomes 0 [t]), the timer stops measuring the actual charging time tm. This makes it possible to measure the actual charging time tm. Note that the weight of the blast furnace raw materials may not become 0 [t] if raw materials continue to remain in the hopper. In this case, the fact that the weight of the blast furnace raw materials has stopped changing can be regarded as the fact that there is no more raw materials in the hopper.

On the other hand, in a structure in which the blast furnace raw materials simply pass through a collecting hopper, if a load cell is provided in the collecting hopper, the load cell measurement value (weight of the blast furnace raw materials) rises from 0 [t] and then returns to 0 [t] as the blast furnace raw materials move. Here, the timing to start measuring the actual charging time tm is when the load cell measurement value starts to rise from 0 [t], and the timing to end measuring the actual charging time tm is when the load cell measurement value becomes 0 [t] again. Note that the weight of the blast furnace raw materials may not become 0 [t] due to blast furnace raw materials continuing to remain in the hopper. In this case, the fact that the weight of the blast furnace raw materials has stopped changing can be regarded as the blast furnace raw materials being gone from the hopper.

In the second measurement method, first, an acoustic sensor is installed in a hopper (not shown) that stores blast furnace raw materials and in the supply path following the hopper. The acoustic sensor detects the sound generated when the blast furnace raw materials move from the hopper to the chute 2, and the position of the acoustic sensor can be determined appropriately as long as this purpose is achieved. The hopper referred to here is, as mentioned above, the hopper that is located closest to the chute 2 in the supply path of the blast furnace raw materials.

When the gate of the hopper is opened (i.e., when the charging of the blast furnace raw materials begins), the timer starts measuring the actual charging time tm. While the blast furnace raw materials are being supplied from the hopper to the chute 2, sound is generated as the raw materials move, and this sound can be detected by the acoustic sensor. When the sound associated with the movement of the raw materials stops, it can be determined that there is no more raw materials left in the hopper. When it is determined using the acoustic sensor that there is no more raw materials left in the hopper, the timer stops measuring the actual charging time tm. This allows the actual charging time tm to be measured.

Next, the rotation number error Er will be explained using Figures 3 and 4. Figures 3 and 4 show a plane perpendicular to the furnace height direction in the blast furnace 1, with the charging start position set to 0 [deg].

Figure 3 is a schematic diagram (one example) of the final rotation when the charging of blast furnace raw materials is completed with fewer rotations than the set number (when the rotation number error Er is -0.2 [rotations]). In other words, Figure 3 is a schematic diagram showing a state in which blast furnace raw materials are charged without the final rotation reaching one revolution around the furnace circumference.

The arrow R1 in FIG. 3 indicates the rotation direction of the chute 2 (here, to the right) and the area where the blast furnace raw materials are charged (the area from the position where charging starts to the position where charging ends). In FIG. 3, the area A1 is an area where charging is not performed in the final rotation and the amount of blast furnace raw materials charged is small (area where the charging amount is insufficient). Therefore, the amount of blast furnace raw materials charged in the area R1 is greater than that in the area A1. In the example shown in FIG. 3, the actual charging time tm is shorter than the scheduled charging time (N×tr), so the rotation number error Er calculated from the above formula (1) indicates a negative value (here, -0.2 [rotations]). Note that if the actual charging time tm matches the scheduled charging time (N×tr), the rotation number error Er is 0 [-].

Figure 4 is a schematic diagram (one example) of the final rotation when the charging of blast furnace raw materials is completed more than the set number of rotations (when the rotation number error Er is +0.1 [rotations]). In other words, Figure 4 is a schematic diagram showing the state in which the final rotation exceeds one revolution in the furnace circumferential direction and the blast furnace raw materials are charged.

The arrow R2 in FIG. 4 indicates the rotation direction of the chute 2 (here, to the right) and the area where the blast furnace raw materials are charged (the area from the position where charging starts to the position where charging ends). In FIG. 4, area A2 is an area where the charging of blast furnace raw materials overlaps during the final rotation, and is an area where excessive blast furnace raw materials are charged (area of excessive charging). In the example shown in FIG. 4, the actual charging time tm is longer than the planned charging time (N×tr), so the rotation number error Er calculated from the above formula (1) indicates a positive value (here, +0.1 [rotations]).

In the above explanation, the rotation number error Er is calculated based on the actual charging time tm, the time tr, and the set number of rotations N, but this is not limited to the above. For example, a camera can be used to photograph the inside of the blast furnace 1, and the position where the blast furnace raw materials first fell and the position where the blast furnace raw materials last fell can be identified by image analysis. The rotation number error Er can also be calculated based on these positions.

(Distribution of ratio R)
In this embodiment, in order to determine the charging start position and the rotation direction of the chute 2 when charging the blast furnace raw materials, a ratio R described below is calculated.

As described below, the ratio R is the ratio [-] of the occurrence number Nex to the total number of charging times Nt, and is calculated based on the charging start position and rotation direction when charging the blast furnace raw materials, and the rotation number error Er. Here, the ratio R is expressed by the following formula (2). The ratio R is calculated for both coke and ore.

The total number of charging times Nt is the cumulative number of times blast furnace raw materials have been charged at a predetermined number of times Nd. In other words, the total number of charging times Nt is counted up every time blast furnace raw materials (coke or ore) are charged. Here, the total number of charging times Nt is linked to the predetermined number of times Nd.

The occurrence count Nex is the number of times that an area occurs in which the amount of charged raw materials is relatively large in the circumferential direction of the furnace during charging of raw materials for the blast furnace, as explained in Figures 3 and 4. As can be seen from Figures 3 and 4, the area in which the amount of charged raw materials is large (area R1 in Figure 3, or area A2 in Figure 4) can be identified by its position in the circumferential direction of the blast furnace 1 (hereinafter referred to as the "circumferential position"), so the occurrence count Nex can be counted for each circumferential position.

For example, if there is an area with a relatively large amount of loading at the 36[deg] furnace periphery position, the number of occurrences Nex at the 36[deg] furnace periphery position is counted up. On the other hand, if there is no area with a relatively large amount of loading at the 36[deg] furnace periphery position, the number of occurrences Nex at the 36[deg] furnace periphery position is not counted up. The interval between the furnace periphery positions when counting up can be set arbitrarily.

In this way, by counting the number of occurrences Nex for each furnace circumference position, the ratio R can be obtained for each furnace circumference position. This allows the distribution of ratio R according to furnace circumference position (hereinafter, simply referred to as the "distribution of ratio R"). Here, as can be seen from the above formula (2), the possible values of ratio R are 0.0 to 1.0 [-].

In one charge, the state shown in Figures 3 and 4 can be determined based on the rotation number error Er in this charge. For example, if the rotation number error Er is a positive value, it can be determined that the area (excessive charging amount) A2 shown in Figure 4 has occurred. Then, by considering the charging start position and the rotation direction, the position of the area (excessive charging amount) A2 in the furnace circumferential direction can be determined. The position of the area (excessive charging amount) A2 in the furnace circumferential direction can be determined by two furnace circumferential positions corresponding to both ends of the area (excessive charging amount) A2 in the furnace circumferential direction. At the furnace circumferential positions included between these two furnace circumferential positions (i.e., the area (excessive charging amount) A2), the occurrence number Nex is counted up as described above.

On the other hand, if the rotation number error Er is a negative value, the amount of material charged is relatively large in region R1 shown in Figure 3, so the number of occurrences Nex is counted up at the furnace circumference position that includes region R1, as described above.

(Method of charging raw materials into a blast furnace)
A method for determining the conditions (charging start position and rotation direction) for charging the blast furnace raw materials into the blast furnace 1 will be described with reference to the flowchart shown in Fig. 5. By determining the conditions for charging the blast furnace raw materials as in this embodiment and charging the blast furnace raw materials into the blast furnace 1 according to these conditions, it is possible to reduce the variation in the charging amount in the circumferential direction for each blast furnace raw material layer (coke layer CL or ore layer OL).

In this embodiment, after charging blast furnace raw materials (coke and ore) multiple times, the conditions for charging the blast furnace raw materials from the next time onwards are determined. For example, when charging blast furnace raw materials for the first time, the charging conditions (charging start position and rotation direction) can be determined according to predetermined rules. An example of the predetermined rules is shown in Table 1 below.

According to the rules shown in Table 1 above, the starting position for charging blast furnace raw materials (coke in this case) is set to 0 degrees, and the starting position is shifted by 90 degrees each time blast furnace raw materials (coke and ore) are charged. The rotation direction of the chute 2 remains the same (rightward or leftward) from when the starting position for charging returns to 0 degrees from 0 degrees. In Table 1 above, the rotation direction is rightward for the first and second charges, changes to the leftward for the third and fourth charges, and changes to the rightward again for the fifth and sixth charges.

In step S101, the rotation number error Er for the next blast furnace raw material charge is set. The rotation number error Er can be set according to the type of blast furnace raw material (coke and ore), or a common rotation number error Er can be set regardless of the type of blast furnace raw material. The rotation number error Er can be set taking into account the rotation number error Er when blast furnace raw material has already been charged, or a predetermined value can be set.

When taking into consideration the rotation number error Er when blast furnace raw materials have already been charged, for example, the average value of the rotation number error Er in a predetermined number of past (most recent) blast furnace raw material charges can be calculated and this average value can be set as the rotation number error Er. It is also possible to set the rotation number error Er in the immediately preceding blast furnace raw material charge.

In step S102, a combination of the charging start position and the rotation direction of the chute 2 when the next blast furnace raw materials are charged is provisionally set. In this provisional setting, the charging start position is selected from the multiple charging start positions previously determined. The rotation direction is either to the right or to the left. The total number of combinations of charging start positions and rotation directions is determined according to the total number of selectable charging start positions and the number of rotation directions (2).

In step S103, the distribution of the ratio R is calculated based on the combination of the rotation number error Er set in the process of step S101 and the charging start position and rotation direction provisionally set in the process of step S102. The method for calculating the distribution of the ratio R is as described above. The distribution of the ratio R calculated in the process of step S103 is a distribution that takes into account the conditions (charging start position and rotation direction) when the blast furnace raw materials have already been charged and the conditions (charging start position and rotation direction) when the next blast furnace raw materials will be charged. Here, the conditions (charging start position and rotation direction) when the blast furnace raw materials have already been charged may be all past charging conditions, or may be the charging conditions for a predetermined number of times in the past (most recent).

In step S104, the standard deviation of the ratio R is calculated based on the distribution of the ratio R obtained in the processing of step S103, and the calculated standard deviation is stored. The standard deviation can be stored in the storage unit 13 (see FIG. 6) described later in a state linked to the combination of the charging start position and the rotation direction provisionally set in the processing of step S102.

In step S105, it is determined whether or not provisional settings have been made for all combinations of loading start positions and rotation directions. If provisional settings have not been made for all combinations, the process returns to step S102. Then, for combinations for which provisional settings have not been made, the process repeats steps S102 to S104 to find the standard deviation of ratio R. On the other hand, if provisional settings have been made for all combinations, the process proceeds to step S106. If provisional settings have been made for all combinations, the standard deviation of ratio R is obtained for each combination.

In step S106, the smallest standard deviation of the ratio R for all combinations is identified.

In step S107, the charging start position associated with the standard deviation (minimum value) identified in the processing of step S106 is determined as the charging start position when the next blast furnace raw materials are charged. In addition, the rotation direction associated with the standard deviation (minimum value) identified in the processing of step S106 is determined as the rotation direction of chute 2 when the next blast furnace raw materials are charged.

When the charging start position and rotation direction are determined in the processing of step S107, the next charging of the blast furnace raw materials is performed based on the determined charging start position and rotation direction. As described above, when the charging start position is set to the position of chute 2 in the furnace circumferential direction, the position where the blast furnace raw materials land does not need to exactly match the determined charging start position, taking into account the variation in the movement trajectory of the blast furnace raw materials falling from chute 2 and the variation in the position of chute 2. The deviation between the position where the blast furnace raw materials land and the determined charging start position (deviation in the furnace circumferential direction) may be within an allowable range. This allowable range may be, for example, within a range of 20% (72 degrees as an angle) or less of the total length in the furnace circumferential direction at the determined charging start position.

In the process shown in FIG. 5, the standard deviation of the ratio R is calculated, but this is not limiting and any parameter that can grasp the variance in the distribution of the ratio R may be used. For example, the difference between the ratio R (maximum value) and the ratio R (minimum value) in the distribution of the ratio R may be used as this parameter.

According to this embodiment, the blast furnace raw materials are charged based on the combination of the charging start position and rotation direction that minimizes the standard deviation of the ratio R, thereby reducing the variation in the charging amount in the circumferential direction of the furnace. By charging the blast furnace raw materials as in this embodiment, the blast furnace raw materials can be actively charged into areas where the ratio R is low, reducing the variation in the charging amount in the circumferential direction of the furnace. Each time this charging of the blast furnace raw materials is repeated, the charging amount in the circumferential direction of the furnace can be made uniform.

In this embodiment, the ratio R is calculated for each furnace circumferential position, but this is not limiting. As described above, it is sufficient to know that there are areas in the furnace circumferential direction where the loading amount is relatively large, so instead of the ratio R, for example, the occurrence number Nex described above can be used. In other words, instead of the distribution of the ratio R, the distribution of the occurrence number Nex according to the furnace circumferential position can be used. Here, the ratio R and the occurrence number Nex correspond to the "parameter related to the occurrence number" in this invention.

The process shown in FIG. 5 can be realized by the operation of the charging method determination device 10 shown in FIG. 6. The charging method determination device 10 only needs to have a portion that performs each process shown in FIG. 5. Specifically, the charging method determination device 10 only needs to have an acquisition unit 11, a calculation unit 12, a storage unit 13, and a determination unit 14, as shown in FIG. 6.

The acquisition unit 11 acquires information for calculating the distribution of the rotation number error Er and the ratio R. The information for calculating the rotation number error Er includes the actual charging time tm, the time tr, and the set number of rotations N. The information for calculating the distribution of the ratio R is the charging start position, the rotation direction, and the rotation number error Er.

The calculation unit 12 calculates the rotation number error Er based on the above formula (1), calculates the distribution of the ratio R based on the charging start position, the rotation direction, and the rotation number error Er, and calculates the standard deviation of the ratio R. The storage unit 13 stores the standard deviation of the ratio R in the processing of step 104 shown in FIG. 5. The determination unit 14 determines the charging start position and the rotation direction of the chute 2 when charging the next blast furnace raw materials based on the standard deviation of the ratio R.

The operation of the charging method determination device 10 described above can be realized by a program (the charging method determination program of the present invention). Specifically, this program can be realized by storing a computer program prepared in advance to realize each of the above-mentioned functions in an auxiliary storage device, and a control unit such as a CPU reading the program stored in the auxiliary storage device into a main storage device, and the control unit executing the program read into the main storage device to operate each function. Each function can be operated by one control device, or by multiple control devices connected to each other.

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

The following describes examples of the present invention. Note that the present invention is not limited to the examples described below.

A test furnace that was one-third the size of an actual furnace was used to conduct a blast furnace raw material charging test. In order to evaluate the variation in the amount of blast furnace raw material charged in the examples and comparative examples, the pretreatment described below was carried out. After the pretreatment, the blast furnace raw material was charged in the examples and comparative examples.

(Pretreatment)
As shown in Table 2 below, six charges of blast furnace raw materials (coke and ore) were charged while changing the charging start position and the rotation direction. Table 2 below also shows the rotation number error Er when charging each blast furnace raw material. Table 2 below is the same as Table 1 above in terms of the charging start position and the rotation direction.

After the blast furnace raw materials shown in Table 2 were charged, the distribution of the ratio R was calculated for each of the coke and ore. The distribution of the ratio R for the coke is shown in Figure 7, and the distribution of the ratio R for the ore is shown in Figure 8.

(Example)
After the above-mentioned pretreatment charging, the charging start position and the rotation direction of the chute 2 when charging the coke in the seventh and eighth charges were determined based on the standard deviation of the ratio R related to the coke. Also, the charging start position and the rotation direction of the chute 2 when charging the ore in the seventh and eighth charges were determined based on the standard deviation of the ratio R related to the ore. Here, in setting the combination of the charging start position and the rotation direction, the options for the charging start position were set to four, 0 [deg], 90 [deg], 180 [deg], and 270 [deg]. The options for the rotation direction were the right direction and the left direction. In this case, the total number of combinations was 16. In this embodiment, four charging start positions were set as described above, and four chargings of blast furnace raw materials were considered as one unit, so the charging start position and the rotation direction were determined for the seventh and eighth charges corresponding to one unit. Here, the charging start position and the rotation direction can also be determined for each charge.

As the rotation number error Er when charging coke in the seventh and eighth charges, the average value of the rotation number error Er for charging coke in the six charges in Table 2 above (0.133 [rotations]) was used. Also, as the rotation number error Er when charging ore in the seventh and eighth charges, the average value of the rotation number error Er for charging ore in the six charges in Table 2 above (0.117 [rotations]) was used.

For the charging of coke in the seventh and eighth charges, all combinations of the charging start position and rotation direction were set, and the distribution of ratio R was obtained when coke was charged in each combination. This distribution is the distribution of ratio R when coke was charged in the first to eighth charges. Then, the standard deviation was calculated from each of the calculated distributions of ratio R, and the combination with the smallest standard deviation of ratio R was selected from the 16 combinations mentioned above.

In this embodiment, when the coke charging start position in the seventh charge is 90 degrees and the chute 2 rotates to the right, and when the coke charging start position in the eighth charge is 270 degrees and the chute 2 rotates to the right, the standard deviation of the ratio R is 0.104, which is the minimum value. Therefore, in the seventh charge, coke charging starts at the charging start position of 90 degrees and the chute 2 rotates to the right, and in the eighth charge, coke charging starts at the charging start position of 270 degrees and the chute 2 rotates to the right. Here, the charging start position is the position of the chute 2 in the furnace circumferential direction. It is also possible to switch the seventh and eighth charges.

Next, for the charging of ore in the seventh and eighth charges, all combinations of charging start positions and rotation directions were set, and the distribution of ratio R was obtained when ore was charged using each combination. This distribution is the distribution of ratio R when ore was charged in the first through eighth charges. Then, the standard deviation was calculated from each of the calculated distributions of ratio R, and the combination with the smallest standard deviation of ratio R was selected from the 16 combinations mentioned above.

In this embodiment, when the ore charging start position in the seventh charge is 90 degrees and the chute 2 rotates to the left, and when the ore charging start position in the eighth charge is 90 degrees and the chute 2 rotates to the left, the standard deviation of the ratio R is 0.094, which is the minimum value. Therefore, in the seventh charge, the ore charging start position is 90 degrees and the chute 2 is rotated to the left, and in the eighth charge, the ore charging start position is 90 degrees and the chute 2 is rotated to the left. Here, the charging start position is the position of the chute 2 in the furnace circumferential direction. In this case, the seventh and eighth charges had the same conditions, but if they are different, they can be interchanged.

The charging conditions for this embodiment are summarized in Table 3 below. As described above, the rotation number error shown in Table 3 below is the average value (temporary set value) of the rotation number error Er for the charging of six charges of blast furnace raw materials, and is not an actual value.

Comparative Example
After the above-mentioned pretreatment charging, coke and ore were charged in order according to the rules shown in Table 2 above.

According to the rules shown in Table 2 above, when charging coke in the seventh charge, the charging start position is 0 [deg] and the rotation direction is to the left. The rotation number error Er in this charging was 0.1 [rotations]. Also, when charging coke in the eighth charge, the charging start position is 180 [deg] and the rotation direction is to the left. The rotation number error Er in this charging was 0.2 [rotations].

According to the rules shown in Table 2 above, when ore is charged in the seventh charge, the charging start position is 90 [deg] and the rotation direction is to the left. The rotation number error Er in this charging was 0.0 [rotations]. When ore is charged in the eighth charge, the charging start position is 270 [deg] and the rotation direction is to the left. The rotation number error Er in this charging was 0.2 [rotations].

The charging conditions for the comparative example described above are summarized in Table 4 below. The rotation number errors shown in Table 4 below are actual values.

Figure 9 shows the distribution of ratio R in the pretreatment, examples, and comparative examples described above with respect to coke charging. The distribution of ratio R in the pretreatment is the same as the distribution of ratio R shown in Figure 7. The distribution of ratio R in the examples is the distribution of ratio R after the coke charging (8 charges) described in the examples described above. The distribution of ratio R in the comparative examples is the distribution of ratio R after the coke charging (8 charges) described in the comparative examples described above. In the examples and comparative examples, the rotation number error (actual value) shown in Table 4 above is used to calculate the distribution of ratio R.

As can be seen from Figure 9, the variation in ratio R was reduced in the embodiment compared to the comparative example. Therefore, it can be seen that this embodiment can reduce the variation in the amount of coke charged in the circumferential direction of the furnace. When the standard deviations were calculated based on the distribution of ratio R shown in Figure 9, the results are shown in Table 5 below, with this embodiment having the smallest standard deviation.

Figure 10 shows the distribution of ratio R in the pretreatment, examples, and comparative examples described above with respect to ore charging. The distribution of ratio R for pretreatment is the same as the distribution of ratio R shown in Figure 8. The distribution of ratio R for the examples is the distribution of ratio R after the ore charging (8 charges) described in the examples described above. The distribution of ratio R for the comparative examples is the distribution of ratio R after the ore charging (8 charges) described in the comparative examples described above. In the examples and comparative examples, the rotation number error (actual value) shown in Table 4 above is used to calculate the distribution of ratio R.

As can be seen from Figure 10, the variation in ratio R was reduced in the embodiment compared to the comparative example. Therefore, it can be seen that this embodiment can reduce the variation in the amount of ore charged in the circumferential direction of the furnace. When the standard deviations were calculated based on the distribution of ratio R shown in Figure 10, the results are shown in Table 6 below, with this embodiment having the smallest standard deviation.

1: blast furnace, 2: chute, 3: furnace wall, RA: rotating shaft, CL: coke layer,
OL: ore layer, θ: tilt angle

Claims (7)

A method for determining how to charge blast furnace raw materials into a bell-less blast furnace by rotating a rotating chute, comprising:
When the same type of blast furnace raw materials is charged again after being charged a plurality of times, a parameter relating to the frequency of occurrence of regions in which the amount of the blast furnace raw materials charged in the blast furnace is relatively large in the circumferential direction is calculated for each position in the circumferential direction of the furnace based on the charging start position and the turning direction and a turning number error indicating the deviation of the actual turning number from the set turning number of the turning chute for all combinations of a plurality of predetermined charging start positions and turning directions of the turning chute,
Calculating the variation of the parameter for each of the combinations based on the distribution of the parameter according to the position in the furnace circumferential direction;
The charging start position when the minimum variation is obtained is determined as the charging start position when the same type of blast furnace raw material is charged again, and the rotation direction when the minimum variation is obtained is determined as the rotation direction of the rotating chute when the same type of blast furnace raw material is charged again.
A method for determining blast furnace raw material charging, comprising: The method for determining the charging of raw materials for a blast furnace according to claim 1, characterized in that the variation is the standard deviation of the parameter. The method for determining the charging of blast furnace raw materials according to claim 1 or 2, characterized in that the parameter is the ratio of the occurrence number to the predetermined number of charging times of blast furnace raw materials. The method for determining the charging of blast furnace raw materials according to any one of claims 1 to 3, characterized in that when calculating the parameters for each position in the furnace circumferential direction, the rotation number error is determined from the rotation number error in past charging of blast furnace raw materials. The method for determining the charging of blast furnace raw materials according to any one of claims 1 to 4, characterized in that the rotation number error includes a case where the actual number of rotations is greater than the set number of rotations, and the blast furnace raw materials are charged after the final rotation exceeds one revolution in the furnace circumferential direction, and a case where the actual number of rotations is less than the set number of rotations, and the blast furnace raw materials are charged before the final rotation reaches one revolution in the furnace circumferential direction. A blast furnace raw material charging method determination device for determining a method for charging blast furnace raw materials into a bell-less type blast furnace by rotating a rotating chute, the device comprising: a calculation unit and a determination unit;
The calculation unit is
When the same type of blast furnace raw materials is charged again after being charged a plurality of times, a parameter relating to the frequency of occurrence of regions in which the amount of charged blast furnace raw materials is relatively large in the circumferential direction of the furnace is calculated for each position in the circumferential direction of the furnace for all combinations of a plurality of predetermined charging start positions and rotation directions of the rotating chute, based on the charging start position and the rotation direction, and a rotation number error indicating the deviation of the actual rotation number from the set rotation number of the rotating chute; and
Calculating the variation of the parameter for each of the combinations based on the distribution of the parameter according to the position in the furnace circumferential direction;
The determination unit determines the charging start position when the minimum variation is obtained as the charging start position when the same type of blast furnace raw material is charged again, and determines the rotation direction when the minimum variation is obtained as the rotation direction of the rotating chute when the same type of blast furnace raw material is charged again.
A device for determining a charging method for blast furnace raw materials. A program for causing a computer to execute the following steps in order to determine a method for charging blast furnace raw materials into a bell-less blast furnace by rotating a rotating chute,
When the same type of blast furnace raw materials is charged again after being charged a plurality of times, a parameter relating to the frequency of occurrence of regions in which the amount of the blast furnace raw materials charged in the blast furnace is relatively large in the circumferential direction is calculated for each position in the circumferential direction of the furnace based on the charging start position and the turning direction and a turning number error indicating the deviation of the actual turning number from the set turning number of the turning chute for all combinations of a plurality of predetermined charging start positions and turning directions of the turning chute,
Calculating the variation of the parameter for each of the combinations based on the distribution of the parameter according to the position in the furnace circumferential direction;
The charging start position when the minimum variation is obtained is determined as the charging start position when the same type of blast furnace raw material is charged again, and the rotation direction when the minimum variation is obtained is determined as the rotation direction of the rotating chute when the same type of blast furnace raw material is charged again.
A program for determining a charging method for blast furnace raw materials.