Blast furnace raw material charging decision method, charging method decision device, and charging method decision program

Abstract

To reduce variation in an amount of a raw material (coke and ore) to be charged into a blast furnace in a furnace circumferential direction.SOLUTION: A method for determining charging of a raw material into a blast furnace calculates a parameter relating to an occurrence frequency in a region in which the amount of the raw material to be charged is relatively large in a furnace circumferential direction for each position in the furnace circumferential direction, for all combinations of a plurality of prescribed charging start positions, and turning directions of a turning chute, when the same kind of raw materials are charged into a blast furnace a plurality of times and then the raw material is charged into the blast furnace again. The parameter is calculated from the charging start position, the turning direction and the turning number error. For all the combinations, variation in parameters is calculated on the basis of 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 a charging start position when the same kind of raw material is charged into the blast furnace again. The turning direction when the minimum variation is obtained is determined as a turning direction of a turning chute when the same kind of raw material is charged into the blast furnace again.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a charging method, a charging method determination device, and a charging method determination program for determining a method of charging blast furnace raw materials into a bell-less type blast furnace having a rotating chute. [Background technology]

[0002] For stable operation of a blast furnace, it is necessary to stabilize the gas flow in 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 furnace circumferential direction, there will be variation in the gas flow in the furnace circumferential direction. Therefore, in Patent Document 1, the position at which the charging of the blast furnace raw materials starts (charging start position) is shifted in the circumferential direction (furnace circumferential direction) by a predetermined amount for each charge of blast furnace raw materials. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-336411 A [Patent Document 2] JP 2018-48361 A [Patent Document 3] Japanese Patent Application Publication No. 8-188806 [Patent Document 4] Japanese Patent Application Laid-Open No. 58-123808 [Patent Document 5] Japanese Patent Application Publication No. 6-10018 [Patent Document 6] Patent No. 3948162 Summary of the Invention [Problem to be solved by the invention]

[0004] However, simply shifting the charging start position in the furnace circumferential direction as in Patent Document 1 may not reduce the variation in the charging amount of blast furnace raw materials in the furnace circumferential direction, as will be described later.

[0005] According to the invention described in Patent Document 1, if the number of revolutions of the chute is the same each time the blast furnace raw materials are charged, it is possible to reduce the variation in the charging amount 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.

[0006] 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 fed 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 taken to feed the raw materials from the hopper to the chute differs, and the time taken from the start to the end of the charging of 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 for a blast furnace are, the shorter the charging time. As a result, there is variation in the number of revolutions of the chute from the start to the end of the charging of the raw materials for a blast furnace.

[0007] 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 of the furnace. [Means for solving the problem]

[0008] The first invention of the present application is a method for determining how to charge 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 regions 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 a rotation number error indicating the deviation of the actual number of rotations from the set number of rotations of the rotating chute.

[0009] 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.Then, 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 are charged again.Then, 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 are charged again.

[0010] The above-mentioned variation can be a standard deviation of a parameter, and the ratio of the number of occurrences to the number of predetermined charging times of the blast furnace raw materials can be used as the parameter.

[0011] When calculating the parameters for each position in the furnace circumferential direction, the rotation number error can be determined from the rotation number error in the past charging of blast furnace raw materials. The rotation number error includes a case where the actual rotation number is more than the set rotation number, and the blast furnace raw materials are charged with the final rotation exceeding one revolution in the furnace circumferential direction, and a case where the actual rotation number is less than the set rotation number, and the blast furnace raw materials are charged without the final rotation reaching one revolution in the furnace circumferential direction.

[0012] The second invention of the present application is a blast furnace raw material charging method determination device that determines a method for charging blast furnace raw materials into a bell-less type blast furnace by rotating a rotating chute, and has a calculation unit and a determination unit.

[0013] The calculation unit calculates, for each position in the circumferential direction of the furnace, a parameter related to the number of occurrences of regions in which the amount of blast furnace raw materials charged in the circumferential direction of the furnace is relatively large for all combinations of a plurality of predetermined charging start positions and rotation directions of the rotating chute when the same type of blast furnace raw materials is charged again after being charged multiple times. This parameter is calculated from the charging start position and rotation direction, and a rotation number error indicating the deviation of the actual number of rotations from the set number of rotations of the rotating chute. Then, the calculation unit 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.

[0014] 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 are charged again. The determination unit also determines the swivel direction when the minimum variation is obtained as the swivel direction of the swivel chute when the same type of blast furnace raw materials are charged again.

[0015] The third invention of the present application is a program for causing a computer to execute the following steps to determine a method for charging blast furnace raw materials into a bell-less type 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 regions 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 a rotation number error indicating the deviation of the actual number of rotations from the set number of rotations of the rotating chute.

[0016] 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 are charged again. Also, 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 are charged again. Effect of the Invention

[0017] According to the present invention, it is possible to reduce variation in the amount of blast furnace raw materials charged in the circumferential direction of the furnace. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a diagram showing a part of the internal structure of a blast furnace. [Diagram 2] FIG. 2 is a diagram illustrating the starting position of charging blast furnace raw materials. [Diagram 3]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. [Figure 4] FIG. 10 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. [Diagram 5] 1 is a flowchart showing a process for determining a method for charging blast furnace raw materials. [Figure 6] FIG. 2 is a block diagram showing a configuration of a charging method determination device. [Figure 7] FIG. 13 is a diagram showing the distribution of the ratio R after charging of coke (after 6 charges). [Figure 8] FIG. 13 shows the distribution of the ratio R after ore charging (after 6 charges). [Figure 9] FIG. 2 is a diagram showing the distribution of ratio R in the examples and comparative examples with respect to coke charging. [Figure 10] FIG. 1 is a diagram showing the distribution of ratio R in the examples and comparative examples regarding the charging of ore. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] (The 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.

[0020] A chute 2 (rotating chute) is provided at the top of the blast furnace 1, and the chute 2 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, blast furnace raw materials (coke and ore) supplied to the chute 2 from a hopper (not shown) drop from the tip of the chute 2 and are deposited inside the blast furnace 1 (i.e., the furnace wall 3).

[0021] Coke and ore are charged from the chute 2, and therefore 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 them into the blast furnace 1) is called a dump, and a repeated unit of charging of blast furnace raw materials is called a charge. When forming a coke layer CL, coke is charged by one or more dumps, and when forming an ore layer OL, ore is charged by one or more dumps.

[0022] When blast furnace raw materials are charged into the blast furnace 1, the chute 2 rotates about the rotation axis RA, and changes an angle θ at which the chute 2 is inclined with respect to the rotation axis RA (referred to as a tilt angle).

[0023] 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.

[0024] 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 [deg]) when one circumference in the circumferential direction is 360 [deg]. In this embodiment, the charging start position when charging the blast furnace raw materials is determined from a plurality of predetermined charging start positions. For example, as shown in FIG. 2, four positions of 0 [deg], 90 [deg], 270 [deg], and 360 [deg] can be determined in advance as the charging start position. FIG. 2 shows a plane perpendicular to the furnace height direction in the blast furnace 1.

[0025] The charging start positions are not limited to the four positions shown in Fig. 2, and any number of charging start positions can be determined. In Fig. 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.

[0026] Here, the charging start position can be based on the position of the chute 2 in the furnace circumferential direction, or based 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 specified based on, for example, a simulation using the Discrete Element Method (publicly known literature, ISIJ International, Vol. 57, pp. 272-278). Note that it is not necessary for the actual landing position where the blast furnace raw materials land to completely match the landing position specified by the simulation.

[0027] In this embodiment, the rotation direction is the rotation direction of the chute 2 when the chute 2 is 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 in the clockwise direction, the rotation direction is the "right direction", and when the chute 2 rotates in the counterclockwise direction, 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. In this case, the rotation direction is in an inverse relationship to the rotation direction of the chute 2 when viewed from the top of the blast furnace 1.

[0028] (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 this preset number of revolutions (hereinafter referred to as the "set number of revolutions") N 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).

[0029]

number

[0030] 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 [sec] for the chute 2 to rotate one revolution (360 [deg]). The value of "N x tr" is the time when the chute 2 rotates the set number of rotations N to charge the blast furnace raw materials (hereinafter referred to as "planned charging time").

[0031] According to the above formula (1), when the blast furnace raw materials are charged exceeding the set number of rotations N, the actual charging time tm is longer than the scheduled charging time (N × tr), so the rotation number error Er is a positive value [rotations]. On the other hand, when the blast furnace raw materials are charged before reaching the set number of rotations N, the actual charging time tm is shorter than the scheduled charging time (N × tr), so the rotation number error Er is a negative value [rotations].

[0032] 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 360 ​​[deg].

[0033] The 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 the start of actual charging of the blast furnace raw materials to the end of charging, and there are various methods for measuring the actual charging time tm. Below, two examples of the method for measuring the actual charging time tm are given.

[0034] In the first measurement method, a load cell is first provided in a hopper (not shown) in which the blast furnace raw materials are stored. The hopper referred to here is the hopper located closest to the chute 2 in the supply path of the blast furnace raw materials.

[0035] For example, when hoppers are arranged in two tiers, upper and lower, and the 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 is the hopper closest to chute 2. When blast furnace raw materials are supplied from multiple hoppers arranged in parallel in the horizontal direction to a collecting hopper and then supplied from the collecting hopper to chute 2, the collecting hopper is 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. When blast furnace raw materials are supplied from multiple hoppers arranged in parallel in the horizontal direction to chute 2, each of the multiple hoppers arranged in parallel is the hopper closest to chute 2.

[0036] At the timing when the gate of the hopper is opened (i.e., when the charging of the blast furnace raw materials starts), the timer starts measuring the actual charging time tm. Then, at the timing when the load cell detects that the blast furnace raw materials in the hopper have run out (i.e., the weight of the blast furnace raw materials has become 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] due to the blast furnace raw materials remaining 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 the blast furnace raw materials in the hopper have run out.

[0037] 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 the timing when the load cell measurement value starts to rise from 0 [t], and the timing to end measuring the actual charging time tm is the timing 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 the blast furnace raw materials remaining 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 exhausted from the hopper.

[0038] In the second measurement method, first, an acoustic sensor is provided in a hopper (not shown) in which the blast furnace raw materials are stored 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 appropriately determined as long as this purpose is achieved. The hopper referred to here is, as described above, the hopper located closest to the chute 2 in the supply path of the blast furnace raw materials.

[0039] At the timing when the gate of the hopper is opened (i.e., the timing when the charging of the blast furnace raw materials starts), the measurement of the actual charging time tm using a timer is started. Here, while the blast furnace raw materials are being supplied from the hopper to the chute 2, sound is generated as the blast furnace raw materials move, and this sound can be detected by an acoustic sensor. Then, when the sound associated with the movement of the blast furnace raw materials stops being generated, it can be determined that the blast furnace raw materials in the hopper have run out. At the timing when it is determined using the acoustic sensor that the blast furnace raw materials in the hopper have run out, the measurement of the actual charging time tm using the timer is ended. In this way, the actual charging time tm can be measured.

[0040] Next, the rotation number error Er will be described with reference to 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].

[0041] Fig. 3 is a schematic diagram (one example) of the final rotation when the charging of the blast furnace raw materials is completed with fewer rotations than the set number (when the rotation number error Er is -0.2 [rotations]). That is, Fig. 3 is a schematic diagram showing a state in which the final rotation does not reach one revolution in the furnace circumferential direction and the blast furnace raw materials are charged.

[0042] The arrow R1 shown in FIG. 3 indicates the rotation direction of the chute 2 (here, the right direction) 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 (an area where the charging amount is insufficient). Therefore, the amount of blast furnace raw materials charged in the area R1 is larger than that in the area A1. In the example shown in FIG. 3, since the actual charging time tm is shorter than the scheduled charging time (N×tr), the rotation number error Er calculated from the above formula (1) indicates a negative value (here, −0.2 [rotations]). Note that when the actual charging time tm coincides with the scheduled charging time (N×tr), the rotation number error Er is 0 [−].

[0043] Fig. 4 is a schematic diagram (one example) of the final rotation when the charging of the blast furnace raw materials is completed more than the set number of rotations (when the rotation number error Er is +0.1 [rotations]). That is, Fig. 4 is a schematic diagram showing a state in which the final rotation exceeds one revolution in the furnace circumferential direction and the blast furnace raw materials are charged.

[0044] An arrow R2 shown in Fig. 4 indicates the rotation direction of the chute 2 (here, the right direction) 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, the area A2 is an area where the charging of the blast furnace raw materials overlaps in the charging of the blast furnace raw materials in the final rotation, and is an area where the blast furnace raw materials are excessively charged (an area of ​​excessive charging amount). In the example shown in Fig. 4, since the actual charging time tm is longer than the scheduled charging time (N × tr), the rotation number error Er calculated from the above formula (1) indicates a positive value (here, +0.1 [rotations]).

[0045] In the above description, the rotation number error Er is calculated based on the actual charging time tm, the time tr, and the set rotation number N, but this is not limited to the above. For example, the inside of the blast furnace 1 can be photographed using a camera, 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.

[0046] (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.

[0047] As described later, the ratio R is the ratio [-] of the occurrence number Nex to the total charging number Nt, and is calculated based on the charging start position and rotation direction of 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 each of the coke and ore.

[0048]

number

[0049] The total number of charging times Nt is the cumulative number of times that blast furnace raw materials are charged at a predetermined number of times Nd. That is, the total number of charging times Nt is counted up every time blast furnace raw materials (coke and ore) are charged. Here, the total number of charging times Nt is linked to the predetermined number of times Nd.

[0050] The occurrence count Nex is the number of times that an area where the amount of charging is relatively large in the circumferential direction occurs during the charging of raw materials into the blast furnace, as explained in Figures 3 and 4. As can be seen from Figures 3 and 4, the area where the amount of charging is large (area R1 in Figure 3 or area A2 in Figure 4) can be identified by the 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.

[0051] For example, when there is a region where the charging amount is relatively large at the 36[deg] circumferential position, the occurrence number Nex at the 36[deg] circumferential position is counted up. On the other hand, when there is no region where the charging amount is relatively large at the 36[deg] circumferential position, the occurrence number Nex at the 36[deg] circumferential position is not counted up. The interval between the circumferential positions when counting up can be set arbitrarily.

[0052] In this way, by counting the occurrence frequency Nex for each furnace circumferential position, the ratio R can be obtained for each furnace circumferential position. This allows the distribution of the ratio R according to the furnace circumferential position (hereinafter, simply referred to as the "distribution of the ratio R"). Here, as can be seen from the above formula (2), the value that the ratio R can take is 0.0 to 1.0 [-].

[0053] In one charge, the state shown in FIG. 3 or FIG. 4 can be judged based on the rotation number error Er in this charge. For example, when the rotation number error Er is a positive value, it can be understood that the region (excessive charging amount) A2 shown in FIG. 4 has occurred. Then, by considering the charging start position and the rotation direction, the position of the region (excessive charging amount) A2 in the furnace circumferential direction can be understood. The position of the region (excessive charging amount) A2 in the furnace circumferential direction can be determined by two furnace circumferential positions corresponding to both ends of the region (excessive charging amount) A2 in the furnace circumferential direction. At the furnace circumferential position included between these two furnace circumferential positions (i.e., the region (excessive charging amount) A2), the occurrence number Nex is counted up as described above.

[0054] On the other hand, when the rotation number error Er is a negative value, the amount of loading is relatively large in the region R1 shown in FIG. 3, so that the occurrence number Nex is counted up at the furnace circumference position including the region R1, as described above.

[0055] (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).

[0056] In this embodiment, after charging of blast furnace raw materials (coke and ore) is performed multiple times, the conditions for charging the blast furnace raw materials from the next time onwards are determined. For example, when charging the blast furnace raw materials for the first time, the charging conditions (charging start position and rotation direction) can be determined according to a predetermined rule. An example of the predetermined rule is shown in Table 1 below.

[0057] [Table 1]

[0058] According to the rules shown in Table 1 above, the charging start position when the blast furnace raw materials (here, coke) are initially charged is set to 0 [deg], and the charging start position is shifted by 90 [deg] each time the blast furnace raw materials (coke and ore) are charged. Also, the rotation direction of the chute 2 is the same (rightward or leftward) from when the charging start position changes from 0 [deg] to 0 [deg] again. 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.

[0059] In step S101, a rotation number error Er for the next charging of blast furnace raw materials is set. The rotation number error Er can be set according to the type of blast furnace raw materials (coke and ore), or a common rotation number error Er can be set regardless of the type of blast furnace raw materials. The rotation number error Er can be set in consideration of the rotation number error Er when the blast furnace raw materials have already been charged, or a predetermined value can be set.

[0060] When taking into consideration the rotation number error Er when the blast furnace raw materials have already been charged, for example, the average value of the rotation number errors Er in the past (most recent) predetermined number of chargings of the blast furnace raw materials can be calculated and this average value can be set as the rotation number error Er. Also, the rotation number error Er in the immediately preceding charging of the blast furnace raw materials can be set.

[0061] 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 above-mentioned multiple predetermined charging start positions. The rotation direction is either the right direction or the left direction. The total number of combinations of the charging start position and the rotation direction is determined according to the total number of selectable charging start positions and the number of rotation directions (2).

[0062] 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 the rotation direction temporarily set in the process of step S102. The method of 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 are to 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).

[0063] In step S104, the standard deviation of the ratio R is calculated based on the distribution of the ratio R obtained in the process 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 turning direction provisionally set in the process of step S102.

[0064] In step S105, it is determined whether or not provisional settings have been made for all combinations of charging 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 of steps S102 to S104 is performed to obtain the standard deviation of the 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 the ratio R is obtained for each combination.

[0065] In step S106, the minimum standard deviation is identified from among the standard deviations of the ratios R in all the combinations.

[0066] 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. Also, the rotation direction associated with the standard deviation (minimum value) identified in the processing of step S106 is determined as the rotation direction of the chute 2 when the next blast furnace raw materials are charged.

[0067] When the charging start position and the rotation direction are determined in the process 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 the chute 2 in the furnace circumferential direction, the position where the blast furnace raw materials land does not need to completely match the determined charging start position, considering the variation in the movement trajectory of the blast furnace raw materials falling from the chute 2 and the variation in the position of the 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.

[0068] 5, the standard deviation of the ratio R is obtained, but the present invention is not limited to this and any parameter capable of grasping the variation in the distribution of the ratio R may be used. As this parameter, 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.

[0069] According to this embodiment, the blast furnace raw materials are charged based on the combination of the charging start position and the rotation direction that minimizes the standard deviation of the ratio R, thereby reducing the variation in the charging amount in the circumferential direction. By charging the blast furnace raw materials as in this embodiment, the blast furnace raw materials can be actively charged into the area where the ratio R is low, thereby reducing the variation in the charging amount in the circumferential direction. Each time the charging of the blast furnace raw materials is repeated, the charging amount in the circumferential direction can be made uniform.

[0070] In this embodiment, the ratio R is calculated for each furnace circumferential position, but this is not limited to this. As described above, it is sufficient to know that there is an area in the furnace circumferential direction where the charging 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 the present invention.

[0071] 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 part 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.

[0072] 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 rotation number 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.

[0073] 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 the next blast furnace raw materials are charged based on the standard deviation of the ratio R.

[0074] The above-mentioned operation of the charging method determination device 10 can be realized by a program (the charging method determination program of the present invention). To realize this program, specifically, a computer program prepared in advance to realize each of the above-mentioned functions is stored in an auxiliary storage device, and a control unit such as a CPU reads the program stored in the auxiliary storage device into a main storage device, and the control unit executes 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.

[0075] 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 the recording medium 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. In addition, hardware devices such as integrated circuits (IC chips, etc.) specially designed and configured for the purpose of the present invention are also included as recording media. EXAMPLES

[0076] EXAMPLES Hereinafter, examples of the present invention will be described. However, the present invention is not limited to the examples described below.

[0077] A test furnace with a size of 1 / 3 of a real furnace was used to conduct a charging test of blast furnace raw materials. In order to evaluate the variation in the amount of blast furnace raw materials charged in the examples and comparative examples, the pretreatment described below was carried out. After the pretreatment, the blast furnace raw materials in the examples and comparative examples were charged.

[0078] (Pretreatment) As shown in Table 2 below, 6 charges of blast furnace raw materials (coke and ore) were charged while changing the charging start position and 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 rotation direction.

[0079] [Table 2]

[0080] 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.

[0081] (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 is 16. In this embodiment, as described above, four charging start positions were set, 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.

[0082] The rotation number error Er when charging coke in the 7th and 8th charges was the average value (0.133 [rotations]) of the rotation number error Er for the charging of coke in the 6 charges in Table 2. The rotation number error Er when charging ore in the 7th and 8th charges was the average value (0.117 [rotations]) of the rotation number error Er for the charging of ore in the 6 charges in Table 2.

[0083] 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 the ratio R was obtained when coke was charged in each combination. This distribution is the distribution of the ratio R when coke was charged in the first to eighth charges. Then, the standard deviation was calculated from each of the distributions of the ratio R, and the combination with the smallest standard deviation of the ratio R was selected from the above-mentioned 16 combinations.

[0084] In this embodiment, when the coke charging start position in the seventh charge is 90 [deg] and the rotation direction of the chute 2 is to the right, and when the coke charging start position in the eighth charge is 270 [deg] and the rotation direction of the chute 2 is to the right, the standard deviation of the ratio R was 0.104, which was the minimum value. Therefore, in the seventh charge, coke charging was started at the charging start position of 90 [deg] and the chute 2 was rotated to the right, and in the eighth charge, coke charging was started at the charging start position of 270 [deg] and the chute 2 was rotated to the right. Here, the charging start position was the position of the chute 2 in the furnace circumferential direction. It is also possible to switch the seventh and eighth charges.

[0085] Next, for the charging of the ore in each of the seventh and eighth charges, all combinations of the charging start position and the rotation direction were set, and the distribution of the ratio R was obtained when the ore was charged with each combination. This distribution is the distribution of the ratio R when the ore was charged in the first to eighth charges. Then, the standard deviation was obtained from each of the obtained distributions of the ratio R, and the combination with the smallest standard deviation of the ratio R was determined from the above-mentioned 16 combinations.

[0086] In this embodiment, when the ore charging start position in the seventh charge is 90 [deg] and the rotation direction of the chute 2 is leftward, and when the ore charging start position in the eighth charge is 90 [deg] and the rotation direction of the chute 2 is leftward, the standard deviation of the ratio R was 0.094, which was the minimum value. Therefore, in the seventh charge, the ore charging was started at the charging start position of 90 [deg] and the chute 2 was rotated to the left, and in the eighth charge, the ore charging was started at the charging start position of 90 [deg] and the chute 2 was rotated to the left. Here, the charging start position was the position of the chute 2 in the furnace circumferential direction. In this case, the seventh and eighth charges were under the same conditions, but if they are different, it is possible to switch between the two.

[0087] The charging conditions of this embodiment described above are summarized in the following Table 3. As described above, the rotation number error shown in the following Table 3 is the average value (provisional set value) of the rotation number error Er for the charging of 6 charges of blast furnace raw materials, and is not an actual value.

[0088] [Table 3]

[0089] (Comparative Example) After the above-mentioned pretreatment charging, coke and ore were charged in order according to the rules shown in Table 2 above.

[0090] 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 left. The rotation number error Er in this charging was 0.1 [rotations]. When charging coke in the eighth charge, the charging start position is 180 [deg] and the rotation direction is left. The rotation number error Er in this charging was 0.2 [rotations].

[0091] According to the rules shown in Table 2 above, when charging ore in the seventh charge, the charging start position is 90[deg] and the rotation direction is left. The rotation number error Er in this charging was 0.0[rotations]. When charging ore in the eighth charge, the charging start position is 270[deg] and the rotation direction is left. The rotation number error Er in this charging was 0.2[rotations].

[0092] The charging conditions of the above-mentioned comparative example are summarized in the following Table 4. The rotation number errors shown in the following Table 4 are actual values.

[0093] [Table 4]

[0094] FIG. 9 shows the distribution of ratio R in the above-mentioned pretreatment, examples, and comparative examples with respect to coke charging. The distribution of ratio R in the pretreatment is the same as the distribution of ratio R shown in FIG. 7. The distribution of ratio R in the examples is the distribution of ratio R after the coke charging (8 charges) described in the above-mentioned examples. The distribution of ratio R in the comparative examples is the distribution of ratio R after the coke charging (8 charges) described in the above-mentioned comparative examples. 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.

[0095] As can be seen from Fig. 9, the variation in the ratio R was reduced in the embodiment compared to the comparative example. Therefore, it can be seen that the present 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 the ratio R shown in Fig. 9, the results were as shown in Table 5 below, and the standard deviation in the present embodiment was the smallest.

[0096] [Table 5]

[0097] FIG. 10 shows the distribution of ratio R in the above-mentioned pretreatment, examples, and comparative examples regarding the charging of ore. The distribution of ratio R in the pretreatment is the same as the distribution of ratio R shown in FIG. 8. The distribution of ratio R in the examples is the distribution of ratio R after the charging of ore (8 charges) described in the above-mentioned examples. The distribution of ratio R in the comparative examples is the distribution of ratio R after the charging of ore (8 charges) described in the above-mentioned comparative examples. 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.

[0098] As can be seen from Fig. 10, the variation in the ratio R was reduced in the embodiment compared to the comparative example. Therefore, it can be seen that the variation in the amount of ore charged in the circumferential direction of the furnace can be reduced according to this embodiment. When the standard deviations were calculated based on the distribution of the ratio R shown in Fig. 10, the results are shown in Table 6 below, and the standard deviation in this embodiment was the smallest.

[0099] [Table 6] [Explanation of symbols]

[0100] 1: blast furnace, 2: chute, 3: furnace wall, RA: rotating shaft, CL: coke layer, OL: ore layer, θ: tilt angle

Claims

1. A method for determining how to charge blast furnace raw materials into a bell-less blast furnace by rotating a rotating chute, comprising: When charging the same type of blast furnace raw materials again after charging the same blast furnace raw materials 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 circumferential direction is relatively large 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:

2. 2. The method for determining charging of raw materials for a blast furnace according to claim 1, wherein the variation is a standard deviation of the parameter.

3. 3. The method for determining charging of raw materials for a blast furnace according to claim 1, wherein the parameter is a ratio of the occurrence number of times to a predetermined number of times of charging of raw materials for a blast furnace.

4. A 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.

5. 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 rotation number is greater than the set rotation number, 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 rotation number is less than the set rotation number, and the blast furnace raw materials are charged before the final rotation reaches one revolution in the furnace circumferential direction.

6. 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.

7. A program for causing 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, When charging the same type of blast furnace raw materials again after charging the same blast furnace raw materials 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 circumferential direction is relatively large 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.

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