JP2021167453A - Blast furnace operation method, pulverized coal injection control device, and pulverized coal injection control program - Google Patents

Abstract

To suppress local dispersion of a reducing material ratio in each tuyere region.SOLUTION: A blast furnace operation method includes: a deposition shape acquisition step for acquiring the deposition shape of an ore layer and a coke layer in the blast furnace by one charge over the whole circumferential direction of the furnace; a coke ratio calculation step for calculating a coke ratio of the coke contained in each tuyere region based on the deposition shape obtained in the deposition shape acquisition step; a pulverized coal ratio calculation step for calculating a pulverized coal ratio to be blown into each tuyere region based on the coke ratio calculated in the coke ratio calculation step so that a reducing material ratio in each tuyere region is equal; a descent estimation step for estimating that the ore layer and the coke layer, whose deposition shape was acquired in the deposition shape acquisition step, have descended to a reference position; and a pulverized coal quantity control step for blowing pulverized coal into the blast furnace from each tuyere at the pulverized coal ratio calculated in the pulverized coal ratio calculation step when the ore layer and the coke layer are estimated to have descended to the reference position in the descent estimation step.SELECTED DRAWING: Figure 8

Description

The present invention relates to an operating method of a blast furnace, a pulverized coal injection control device, and a pulverized coal injection control program.

In order to operate the blast furnace stably, it is important to stabilize the gas flow in the blast furnace, in particular, to make the gas flow in the blast furnace uniform in the circumferential direction. When the gas flow in the blast furnace becomes non-uniform in the circumferential direction, the rising temperature of the blast furnace raw material (ore raw material, coke, etc.) deposited in the blast furnace and the reduction rate of the ore raw material become non-uniform in the furnace peripheral direction, and the inside of the blast furnace becomes non-uniform. There is a risk that the blast furnace will not operate stably due to the imbalance of heat.

In Patent Document 1, a pair of thermoelectric pairs are embedded at a plurality of positions along the circumferential direction in the refractory bricks forming the inner wall of the blast furnace at intervals in the radial direction of the blast furnace, and a pair of thermoelectric pairs at each of the above positions. The operation of the blast furnace is characterized in that the heat flux distribution in the circumferential direction of the blast furnace is obtained from the temperature difference between the pairs, and the amount of pulverized coal blown from the tuyere is controlled so that the heat flux distribution becomes uniform in the circumferential direction of the blast furnace. The method is disclosed. In addition, Patent Documents 2 to 5 also disclose a technique for improving the heat balance in the blast furnace by adjusting the amount of pulverized coal in the furnace peripheral direction.

Japanese Patent No. 5854200 JP-A-2018-193599 International Publication No. 2019/18903 Japanese Patent No. 3844858 Japanese Patent No. 5064086

One of the factors that cause the gas flow in the blast furnace to be non-uniform in the peripheral direction is that the coke consumption is non-uniform at the lower part of the furnace in the peripheral direction. If the coke consumption becomes non-uniform in the lower part of the furnace in the furnace circumferential direction, the descent rate of the blast furnace raw material charged into the furnace becomes non-uniform, and the deposition height of the blast furnace raw material becomes non-uniform. As a result, the surface height of the blast furnace raw material (charged material) that is repeatedly charged into the furnace becomes non-uniform, and the blast furnace operation may become unstable.

Here, the present inventors have come up with the concept of a local reducing agent ratio (mass of reducing agent required to produce 1 ton of hot metal) around each tuyere, and the coke consumption in the furnace circumference direction is inconvenient. In order to suppress the uniformity, it was conceived that it is preferable to suppress the local reducing agent ratio around each tuyere in the furnace circumference direction from becoming non-uniform.

In view of this point, the present invention provides a blast furnace operating method, a pulverized coal injection control device, and pulverized powder, which are aimed at suppressing local variations in the reducing agent ratio in each tuyere region corresponding to one or more tuyere. The purpose is to provide a charcoal blowing control program.

In order to solve the above problems, the operating method of the blast furnace according to the present invention is (1) the operating method of the blast furnace in which the ore raw material and coke are charged into the furnace, and the ore layer and the coke layer deposited in the blast furnace. Based on the deposit shape acquisition step of acquiring at least one charge in the entire furnace circumference direction and the deposit shape of the coke layer and the ore layer obtained in the deposit shape acquisition step, one or more tuyere A coke ratio calculation step for calculating the coke ratio of coke contained in each tuyere region of the corresponding furnace height direction fan type, and a coke coke included in each tuyere region calculated in the coke ratio calculation step. Based on the ratio, the deposited shape is acquired in the pulverized coal ratio calculation step for calculating the pulverized coal ratio to be blown into each tuyere region and the deposited shape acquisition step so that the reducing material ratio in each tuyere region becomes equal. A descent estimation step for estimating that the ore layer and the coke layer have descended to a desired reference position, and a descent estimation step for estimating that the ore layer and the coke layer whose deposit shape has been acquired in the deposit shape acquisition step have descended to the reference position. It is provided with a pulverized coal amount control step for injecting pulverized coal into the blast furnace from each tuyere at the pulverized coal ratio calculated in the pulverized coal ratio calculation step when estimated. A method of operating a blast furnace, which is characterized by.

(2) In the sedimentary shape acquisition step, the sedimentary shapes are measured in a plurality of furnace radial directions using a two-dimensional profile meter, and the unmeasured sedimentary shapes in the furnace radial direction are interpolated using the measured sedimentary shapes. The method for operating a blast furnace according to (1) above, characterized in that the deposited shape of the ore layer and the coke layer deposited in the blast furnace is obtained by the operation.

(3) The method for operating a blast furnace according to (1) above, wherein in the step of acquiring the sedimentary shape, the sedimentary shape of the ore layer and the coke layer deposited in the blast furnace is acquired by using a three-dimensional profile meter.

(4) Each tuyere region is characterized in that it has a fan-shaped shape with 360 ° / number of tuyere as a central angle when viewed in the direction of the furnace height, and is formed line-symmetrically with respect to the axis of the tuyere. The method for operating a blast furnace according to any one of (1) to (3) above.

(5) The coke ratio calculation step is a volume calculation for calculating the volumes of the coke layer and the ore layer contained in each tuyere region based on the deposited shape of the coke layer and the ore layer obtained in the deposit shape acquisition step. Using the steps, the volumes of the coke layer and the ore layer included in each tuyere region, and the bulk density of each brand contained in the coke layer and the ore layer, which were calculated in the volume calculation step, each of the above. Based on the mass calculation step for calculating the mass of coke and the mass of the ore raw material contained in the tuyere region and the mass of coke and the mass of the ore raw material calculated in the mass calculation step. Calculated in the O / C ratio calculation step for calculating the mass ratio (O / C ratio) of the ore raw material to coke in each tuyere region, at least the preset ore ratio, and the O / C ratio calculation step. In addition, the above (1) to (4) are provided with a step of calculating the coke ratio of coke contained in each tuyere region by using the O / C ratio in each tuyere region. ) Is described in any one of the methods for operating the blast furnace.

(6) In the pulverized coal ratio calculation step, the coke ratio of coke contained in each tuyere region calculated in the coke ratio calculation step is subtracted from the target reducing material ratio common to all the tuyere regions. The method for operating a blast furnace according to any one of (1) to (5) above, wherein the ratio of pulverized coal blown into each tuyere region is calculated.

(7) The operation of the blast furnace according to any one of (1) to (6) above, wherein the reference position is set in a region from the apex of the estimated fusion zone to the tuyere height. Method.

(8) An operation method of a blast furnace in which an ore raw material and coke are charged into a furnace, in which the deposit shape of the ore layer and the coke layer deposited in the blast furnace is acquired for at least one charge in the entire circumference direction of the furnace. Based on the shape acquisition step and the deposited shape of the coke layer and the ore layer obtained in the deposited shape acquisition step, the coke layer included in each tuyere region of the furnace height direction fan type corresponding to one or more tuyere. And the volume calculation step for calculating the volume of the ore layer, the volume of the coke layer and the ore layer included in each tuyere region calculated in the volume calculation step, and each brand included in the coke layer and the ore layer. A mass calculation step for calculating the mass of coke contained in each tuyere region and the mass of an ore raw material using bulk density, and the coke contained in each tuyere region calculated in the mass calculation step. Calculated by the O / C ratio calculation step for calculating the mass ratio (O / C ratio) of the ore raw material to coke in each tuyere region and the O / C ratio calculation step based on the mass of the ore raw material and the mass of the ore raw material. By dividing the O / C ratio in each tuyere region by the average O / C ratio of the entire tuyere region or a preset O / C ratio, the O / C of each tuyere region is obtained. The O / C relative ratio calculation step for obtaining the relative ratio and the preset pulverized coal ratio are multiplied by the O / C relative ratio in each tuyere region calculated in the O / C relative ratio calculation step. A descent that estimates that the pulverized coal ratio calculation step for calculating the pulverized coal ratio to be blown into each tuyere region and the ore layer and coke layer for which the accumulated shape was acquired in the accumulated shape acquisition step have descended to a desired reference position. Each tuyere calculated in the pulverized coal ratio calculation step when it is estimated that the ore layer and the coke layer whose deposit shape was acquired in the estimation step and the deposit shape acquisition step have descended to the reference position. A method of operating a blast furnace, which comprises a pulverized coal amount control step in which pulverized coal is blown into the blast from each tuyere at a ratio of pulverized coal to be blown into an area.

(9) A pulverized coal injection control device used in a blast furnace in which an ore raw material and coke are charged into a furnace, and the deposited shape of the ore layer and the coke layer deposited in the blast furnace is charged by at least 1 charge over the entire circumference direction of the furnace. Based on the deposit shape acquisition part to be acquired for the minute and the deposit shape of the coke layer and the ore layer obtained by the deposit shape acquisition part, each tuyere region of the furnace height direction visual fan type corresponding to one or more tuyere. Based on the coke ratio calculation unit that calculates the coke ratio of coke contained in, and the coke ratio of coke contained in each tuyere region calculated by the coke ratio calculation unit, the reducing material ratio in each tuyere region. The pulverized coal ratio calculation unit that calculates the pulverized coal ratio to be blown into each tuyere region and the ore layer and coke layer whose accumulated shape has been acquired by the accumulated shape acquisition unit are up to the desired reference position so that When the descent estimation unit estimates that the descent estimation unit and the ore layer and coke layer whose deposit shape has been acquired by the deposit shape acquisition unit have descended to the reference position, the pulverized coal The pulverized coal injection control is provided with a pulverized coal amount control unit for injecting pulverized coal into the blast furnace from each tuyere at the pulverized coal ratio calculated by the ratio calculation unit. Device.

(10) A deposit shape acquisition step of acquiring the deposited shapes of the ore layer and the coke layer deposited in the blast furnace for at least one charge over the entire circumference direction of the furnace, and the coke layer and the coke layer obtained in the deposited shape acquisition step on a computer. In the coke ratio calculation step for calculating the coke ratio of coke contained in each tuyere region of the furnace height direction fan type corresponding to one or more tuyere based on the deposited shape of the ore layer, and the coke ratio calculation step. Based on the calculated coke ratio of coke contained in each tuyere region, the pulverized coal ratio for calculating the pulverized coal ratio to be blown into each tuyere region so that the reducing material ratio in each tuyere region is equal. The calculation step, the descent estimation step for estimating that the ore layer and the coke layer whose deposit shape has been acquired in the deposit shape acquisition step have descended to a desired reference position, and the deposit shape acquisition step have acquired the deposit shape. When the descent estimation step estimates that the ore layer and the coke layer have descended to the reference position, the pulverized coal ratio calculated in the pulverized coal ratio calculation step and blown into each tuyere region is used for each feather. A pulverized coal injection control program characterized by executing a pulverized coal amount control step of injecting pulverized coke into the blast furnace from the mouth.

According to the present invention, it is possible to suppress local variations in the reducing agent ratio in each tuyere region in the furnace circumferential direction. Therefore, it is possible to suppress the non-uniform coke consumption in the furnace peripheral direction, which in turn can contribute to the improvement of the stability of the blast furnace operation.

It is a schematic block diagram of the blast furnace to which this embodiment is applied. It is a block diagram of the pulverized coal injection control device in this embodiment. It is the sedimentary shape of the ore layer and the coke layer acquired by the three-dimensional profile meter. This is the tuyere region in the direction of the furnace height. It is a perspective view of the tuyere region shown in FIG. It is the calculation result of the coke ratio of the coke contained in each tuyere region Q about the acquired sedimentation shape A shown in FIG. It is a calculation result of the pulverized coal blown into each tuyere region Q based on the calculation result of the coke ratio of the coke contained in each tuyere region Q shown in FIG. The flowchart of the blast furnace operation method in this embodiment is shown.

(First Embodiment)
Hereinafter, the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a blast furnace to which the present embodiment is applied. In the blast furnace 1, ore raw materials such as sintered ore, pellets and lump ore are used as the main raw material, and coke and pulverized coal are used as the reducing agent. Further, in recent years, a technique of using unfired coal-containing agglomerate ore as an ore raw material and ferro-coke as coke has been proposed. Includes ferro-coke. The ore raw material and coke are alternately charged in layers from the top of the blast furnace 1. As a result, a massive zone, a fusion zone in which the ore raw material is melted and changed from a solid to a liquid, a dropping zone in which the liquid molten iron or molten slag drops a coke layer, and the like are formed in the furnace of the blast furnace 1. .. The blast furnace may be a bell-type blast furnace or a bellless-type blast furnace. The ore layer may contain coke (for example, small coke, ferro-coke) and auxiliary raw materials in addition to the ore raw material, and the coke layer may also contain blast furnace raw materials other than coke.

(Structure of blast furnace 1)
The blast furnace 1 in the present embodiment includes a tuyere 2, an annular pipe 3, a blow pipe 4, a lance 5 for blowing pulverized coal, a tap 6 and a pulverized coal blowing control device 7. A plurality of tuyere 2s are provided in the lower part of the furnace along the circumferential direction of the blast furnace 1. The annular pipe 3 is arranged so as to surround the lower part of the blast furnace 1. The blow pipe 4 is intermittently provided in the circumferential direction of the annular pipe 3, and each is connected to a different tuyere 2. Each blow pipe 4 is inserted through the pulverized coal blowing lance 5, and the tip of the pulverized coal blowing lance 5 extends into each blow pipe 4. The hot metal outlet 6 is provided to discharge the hot metal accumulated in the bottom of the furnace. In the above configuration, the pulverized coal blowing lance 5 supplies pulverized coal to the inside of the blow pipe 4. The amount of pulverized coal to be supplied is controlled by the pulverized coal injection control device 7. The pulverized coal travels toward the tuyere 2 together with the hot air blown from the annular pipe 3 to the blow pipe 4, and is blown into the blast furnace 1 from the tuyere 2.

(Structure of pulverized coal injection control device 7)
FIG. 2 is a block diagram of the pulverized coal injection control device according to the present embodiment. With reference to FIG. 2, the pulverized coal blowing device 7 includes a storage unit 71 and a control unit 72. The storage unit 71 stores the bulk density DB711 that stores the bulk density of each brand, the ore ratio DB712 that stores the ore ratio, the target reducing material ratio DB713 that stores the target reducing material ratio, and the reference position DB714 that stores the reference position. And. The control unit 72 includes a deposit shape acquisition unit 721, a coke ratio calculation unit 722, a pulverized coal ratio calculation unit 723, a descent estimation unit 724, and a pulverized coal amount control unit 725.

(Deposited shape acquisition unit 721)
The deposit shape acquisition unit 721 acquires the deposit shape of the ore layer and the coke layer deposited in the blast furnace 1 for at least one charge in the entire furnace circumferential direction. One charge is a unit of repeated charging of blast furnace raw materials, and is composed of a plurality of charging dumps (supplying a predetermined weight of blast furnace raw materials from a hopper to a swivel chute or the like and charging the blast furnace 1).
For example, a three-dimensional profile meter is used to acquire the deposited shape. The three-dimensional profile meter acquires the deposited shapes of the ore layer and the coke layer in the furnace radial direction at predetermined angular intervals in the furnace circumferential direction. FIG. 3 schematically shows the sedimentary shape of the ore layer and the coke layer acquired by the three-dimensional profile meter. With reference to the figure, in the present embodiment, after charging one dump each of coke and ore, the coke layer and the ore layer are targeted one by one, and the deposition shape is formed at 1 ° along the furnace circumference direction. Obtained A. Contour lines are drawn every 50 mm on the surface of the charge in FIG. In the present embodiment, one dump of each of the coke and the ore raw material is charged, but the present invention is not limited to this, and at least one of the coke and the ore raw material may be charged in a plurality of dump trucks. Further, the deposited shape may be acquired not only for one charge but also for a plurality of charges.

The measurement interval (angle in the furnace circumferential direction) of the three-dimensional profile meter can be set as appropriate. When the measurement interval (angle in the furnace circumferential direction) of the three-dimensional profile meter is wide, the deposition shape of the unmeasured region may be interpolated as in the case of using the two-dimensional profile meter described later. Further, the measurement data of the three-dimensional profile meter is not limited to the one acquired at the furnace circumferential angle, and may be measured, for example, at grid-like measurement points. In this case, the measurement data is processed into the furnace circumferential angle measurement data. Can be used in the subsequent steps.

The deposited shape of the charge may be obtained using a two-dimensional profile meter. In the case of a two-dimensional profile meter, the deposit shape in a specific furnace radial direction is acquired by one measurement. Therefore, when using a two-dimensional profile meter, the sedimentary shapes of the ore layer and coke layer can be estimated by interpolating the sedimentary shapes of the unmeasured regions using the sedimentary shapes obtained in multiple furnace radial directions. You may.
Here, the acquisition of the deposited shape includes not only receiving the raw measurement data from the profile meter, but also appropriately processing (for example, interpolating) the raw data to acquire the data.

(Coke ratio calculation unit 722)
Based on the sedimentary shape A of the coke layer and the ore layer obtained by the sedimentary shape acquisition unit 721 (hereinafter, also referred to as the acquired sedimentary shape A), in the coke ratio calculation unit 722, each feather corresponding to one or more tuyere 2s. The coke ratio of coke contained in the mouth region (mass of coke required to produce 1 ton of hot metal) is calculated. Here, the "tuyere region" refers to "a region having a predetermined angle corresponding to the tuyere position in the furnace circumferential direction when the acquired sedimentation shape is viewed in the furnace height direction". When setting the tuyere region corresponding to one tuyere 2 (see FIG. 4 described later), for example, each tuyere region can be set with the middle of the adjacent tuyere 2 in the furnace circumferential direction as a boundary. .. Further, for example, each tuyere region can be set with each axis of the tuyere 2 adjacent to each other in the furnace circumference direction as a boundary, and any tuyere region can be set as a repeating unit of a predetermined angle in the furnace circumference direction. ..
When setting the tuyere region corresponding to a plurality of tuyere 2, for example, it is possible to set a plurality of tuyere 2 as one group and set each tuyere region with the middle of adjacent groups in the furnace circumferential direction as a boundary. can. When setting the tuyere region with a plurality of tuyere 2 as one group, it is preferable to divide all tuyere into at least 3 groups or more, that is, the central angle of the tuyere region which is a furnace height fan type is It is preferably 120 ° or less. Here, the "furnace height direction fan type" means "a shape in which the inside of the furnace is divided by a plurality of boundary lines radiating from the center of the furnace toward the furnace wall in the direction of the furnace height".
Further, "coke contained in each tuyere region" includes coke contained in the coke layer of each tuyere region as well as coke (small coke, etc.) contained in the ore layer of the tuyere region. Furthermore, when each tuyere region contains uncalcined coal-bearing lump ore or ferro-coke, the coke contained therein can also be included in the "coke contained in each tuyere region". At this time, in the calculation of the coke ratio below, the entire mass of the uncalcined coke-bearing coke and / or ferro-coke may be considered as coke, and the non-calcined coke-containing coke and / or ferro-coke may be considered. It may be considered after converting to the mass of coke (carbon).

As shown in FIG. 4, the tuyere region Q has, for example, a fan shape having a central angle α (predetermined angle) of 360 ° / number of tuyere (number of tuyere = 28 in this embodiment) when viewed in the direction of the furnace height. Therefore, it can be formed line-symmetrically with respect to the axis L of the tuyere 2. That is, the tuyere region Q in FIG. 4 is set so that each tuyere 2 (tuyere position) is located at the center of the arc portion of each tuyere region in the furnace height direction. FIG. 5 is a perspective view of the tuyere region shown in FIG.

(Procedure for calculating the coke ratio of coke contained in each tuyere area)
The coke ratio calculation unit 722 calculates the coke ratio of coke contained in each tuyere region Q, for example, by the following procedure.
(A) Based on the acquired sedimentary shape A, the volumes of the coke layer and the ore layer contained in the tuyere region Q are calculated for each tuyere region Q.
(B) Using the volume of the coke layer and the ore layer contained in each tuyere region Q and the bulk density of each raw material brand contained in the coke layer and the ore layer obtained in (a), each The mass of coke and the mass of the ore raw material contained in the tuyere region Q are calculated.
(C) Based on the mass of coke contained in each tuyere region Q and the mass of ore raw material obtained in (b), the mass ratio (O / C ratio) of the ore raw material to coke in each tuyere region Q. Is calculated.
(D) The preset ore ratio (mass of the ore raw material required to produce 1 ton of hot metal) is divided by the O / C ratio in each tuyere region Q calculated in (c), and each feather. The coke ratio of the coke contained in the mouth region Q is calculated. The ore ratio is a set value read from the ore ratio DB712, and may be set assuming that the ore layer deposited in the blast furnace 1 has a uniform distribution, but is limited to this. Instead, it is possible to set different values in each tuyere region Q on the assumption that the ore layer deposited in the blast furnace 1 has a non-uniform distribution in the furnace circumference direction.

The above (b) will be described in more detail. By reading out the bulk density of each brand contained in the coke layer and the ore layer from the bulk density DB711 and multiplying by the volume of the coke layer and the ore layer contained in each tuyere region Q obtained in (a) above. The mass of coke and the mass of the ore raw material contained in each tuyere region Q are calculated. The "ore raw material contained in each tuyere region" includes not only the ore raw material contained in the ore layer of each tuyere region but also the ore raw material contained in the coke layer of each tuyere region. As described above, in calculating the mass of coke and the mass of the ore raw material contained in each tuyere region Q, if each tuyere region Q contains unfired coal-containing agglomerate ore or ferro-coke, they are used. The coke (carbon) content and the ore (Fe) content contained in the above may be added up.

For example, when the ore layer contains small coke, the mass of the ore layer is obtained by multiplying the volume of the ore layer in the tuyere region Q obtained in (a) by the "bulk density of the mixed raw material of the ore raw material and the small coke". The mass of the ore raw material contained in the tuyere region Q can be calculated by subtracting the mass of the small coke from the mass. As the mass of the small coke used for this subtraction, the amount of the small coke charged may be simply divided by the total number of tuyere regions Q to obtain the charged amount per tuyere region Q. A different value may be set in each tuyere region Q by simulating a non-uniform distribution in the furnace circumference direction.
Further, the mass of this small coke is calculated by multiplying the volume of the coke layer in the tuyere region Q obtained in (a) by the "bulk density of coke" (that is, the coke layer in the tuyere region Q). The mass of coke contained in the tuyere region Q can be calculated by adding it to the mass of coke contained in.

When the ore layer contains an auxiliary raw material, the mass of the ore layer is obtained by multiplying the volume of the ore layer in the tuyere region Q obtained in (a) by the "bulk density of the mixed raw material of the ore raw material and the auxiliary raw material". By subtracting the mass of the auxiliary raw material from the mass, the mass of the ore raw material contained in the tuyere region Q can be calculated. As the mass of the auxiliary material used for this subtraction, the amount of the auxiliary material charged may be simply divided by the total number of tuyere regions Q to obtain the charged amount per tuyere region Q, and the furnace circumference may be used. A different value may be set in each tuyere region Q by simulating a non-uniform distribution in the direction.

That is, the coal-containing lump coke, coke (small coke, ferro-coke, etc.), auxiliary raw materials, etc. contained in the ore layer may be calculated on the assumption that they are uniformly charged in the furnace circumference direction. The calculation may be performed by weighting in the furnace circumference direction in consideration of the time change of the charge amount due to segregation or the like.
Further, as the bulk density, the bulk density of the main raw material (sintered ore, coke breeze) may be used instead of the bulk density of the mixed raw material as described above. For example, when small coke is contained in the ore layer, in (b), the mass of coke contained in each tuyere region and the mass of the ore raw material are calculated without considering the small coke, and (d). By adding the coke ratio of small coke in, the coke ratio of coke contained in each tuyere region can be calculated. In this case, the "mass of coke contained in each tuyere region" calculated in (b) is "mass of coke in the coke layer of each tuyere region".

For the bulk density of each brand, a value measured in advance is used. The bulk density is the mass per unit bulk volume occupied by a certain blast furnace raw material. The method for measuring the bulk density is not particularly limited, but it can be measured according to, for example, the method for measuring the bulk density of fine ceramic powder (initial bulk density in the constant volume measuring method) specified in JIS R 1628-1997. .. That is, after weighing the measuring container, the blast furnace raw material is put in the measuring container, the mass is measured together with the measuring container, the mass of the measuring container is subtracted to calculate the mass of the blast furnace raw material, and the mass of the blast furnace raw material is measured in the measuring container. It can be measured by dividing by the volume of. In this case, a drum is preferably used as the measuring container, and for example, a drum having a diameter (inner diameter) of 0.56 m, a height of 0.89 m, a volume of 0.22 m ³ , and a mass of 20 kg can be used.
Depending on the calculation accuracy of the volume based on the acquired sedimentary shape A and the quality of the set bulk density, for example, the total mass of the ore raw materials calculated for each tuyere region Q is grasped (operation). It may not match the charge mass (as a condition). For the ore raw material or coke, if there is a discrepancy between the total mass value calculated for each tuyere region Q and the charged amount as the operating condition, correction processing may be performed as appropriate.

Here, for the acquired sedimentary shape A shown in FIG. 3, the coke ratio calculation unit 722 calculated the coke ratio of the coke contained in each tuyere region Q as follows. Each tuyere region Q has a central angle of 360 ° / number of tuyere (number of tuyere = 28) in the direction of the furnace height, and is set to a fan shape formed line-symmetrically with respect to the axis of the tuyere. bottom.
The coke ratio calculation unit 722 calculated the coke ratio of coke contained in each tuyere region Q according to the procedures (a) to (d). The bulk density of the ore was 1.7 [t / m ³ ], the bulk density of coke was 0.5 [t / m ³ ], and the ore ratio was 1.6. 30 [kg / tp] of small coke is mixed in the ore layer, and in (b), the mass of coke contained in each tuyere region and the mass of the ore raw material are calculated without considering the small coke. Then, by adding the coke ratio (30 [kg / tp]) of the small coke in (d), the coke ratio of the coke contained in each tuyere region was calculated.
The calculation result is shown in FIG. The mass [t] of the ore raw material contained in each tuyere region Q and the mass [t] of coke calculated in (b) and the O / in each tuyere region Q calculated in (c). Table 1 shows the C ratio [-] and the coke ratio (CR [kg / tp]) of the coke contained in each tuyere region Q calculated in (d).

(Pulverized coal ratio calculation unit 723)
Based on the coke ratio of coke contained in each tuyere region Q calculated by the coke ratio calculation unit 722, the pulverized coal ratio calculation unit 723 blows the pulverized coal ratio (fine powder per ton of hot metal) into each tuyere region Q. Calculate the amount of charcoal blown). The pulverized coal ratio blown into each tuyere region Q is calculated so that the reducing agent ratio in each tuyere region Q is equal. In the present embodiment, a preset target reducing agent ratio is read out from the target reducing agent ratio DB 713, and coke included in each tuyere region Q calculated by the coke ratio calculation unit 722 from this target reducing agent ratio. By reducing the coke ratio of, the pulverized coal ratio blown into each tuyere region Q is calculated. The target reducing agent ratio is a value common to all tuyere regions Q and can be appropriately set in consideration of the results of blast furnace operation and the like, but can be set to, for example, 500 [kg / tp]. When calculating the pulverized coal ratio to be blown into each tuyere region Q, it is not limited to the case where the reducing agent ratio in each tuyere region Q is exactly equal to the target reducing agent ratio ± 10 [kg / tp]. An error of about 20 [kg / tp] may be allowed between the tuyere region Q having the highest reducing agent ratio and the tuyere region Q having the lowest reducing agent ratio. .. The error between the reducing agent ratio and the target reducing agent ratio in each tuyere region Q is preferably ± 5 [kg / tp] or less, and the tuyere region Q having the highest reducing agent ratio and the tuyere having the lowest reducing agent ratio. The difference from the region Q is preferably 10 [kg / tp] or less.

The reducing agent ratio is represented by the sum of the coke ratio and the pulverized coal ratio. Therefore, by setting the target reducing agent ratio in advance and reducing the coke ratio in each tuyere region calculated from this target reducing agent ratio, the pulverized coal required to set the reducing agent ratio as the target value. The ratio can be calculated.
Here, the "reducing agent ratio" in the present specification is not limited to the reducing agent ratio as a total value obtained by simply adding the coke ratio and the pulverized coal ratio, but is a corrected reducing agent ratio obtained by appropriately correcting the total value. It may be present (see, for example, Japanese Patent Application Laid-Open No. 2019-127628). For example, the reducing agent ratio can be corrected by using the blowing temperature and the blowing humidity of the hot air blown from the tuyere. Specifically, the total value is obtained by multiplying the blowing temperature and the blowing moisture by a predetermined coefficient. It can be corrected by adding or subtracting from. The reducing agent ratio in this embodiment is a total value obtained by simply adding the coke ratio and the pulverized coal ratio.

Based on the calculation result of the coke ratio of coke contained in each tuyere region Q shown in FIG. 6, the pulverized coal ratio (PCR) [kg / kg / kg / tp] is shown in FIG. 7 and Table 2. The target reducing agent ratio in each tuyere region was set to 500 [kg / tp].

(Descent estimation unit 724)
In the descent estimation unit 724, the ore layer and the coke layer (hereinafter referred to as the acquisition target sedimentary layer) whose sedimentary shape has been acquired by the sedimentary shape acquisition unit 721 descend to the reference position based on the reference position read from the reference position DB714. Estimate what you did. The "reference position" is "a position in which the pulverized coal blown from the tuyere can sufficiently reach the tuyere region in the furnace height direction", and is preferably in front of the tuyere. Specifically, it is set in the region from the apex of the fusion zone to the tuyere height, and the fusion zone position can be estimated by a conventionally known method.
The descent speed can be calculated by measuring the surface of the charge at a predetermined cycle (for example, every 10 seconds) using a three-dimensional profile meter. Then, by accumulating the descent speed, it is possible to determine whether or not the charged object has reached the reference position. However, the estimation method is not limited to the three-dimensional profile meter, and a mechanical sounding device, a microwave range finder, or the like can also be used.

(Pulverized coal amount control unit 725)
When the descent estimation unit 724 estimates that the blast furnace to be acquired has descended to the reference position, the pulverized coal amount control unit 725 calculates the pulverized coal ratio calculation unit 723 and blows the pulverized coal into each tuyere region Q. At the charcoal ratio, pulverized coal is blown into the blast furnace 1 from each tuyere 2.
At this time, the pulverized coal amount control unit 725 can convert the pulverized coal amount calculated by the pulverized coal ratio calculation unit 723 to the amount of blown water per hour (for example, t / h) and then output the output. In this conversion, the pulverized coal ratio [kg / tp] blown into each tuyere region Q × the mass of the ore raw material contained in each tuyere region Q [kg / ch] ÷ ore ratio [kg / tp] ÷ each tuyere It can be calculated as the time [h / ch] that the region Q passes through the reference position.

(Flow of blast furnace operation method)
FIG. 8 shows a flowchart of the blast furnace operation method in the present embodiment. With reference to FIG. 2, first, the sedimentary shape acquisition unit 721 acquires the sedimentary shape of the ore layer and the coke layer deposited in the blast furnace 1 for at least one charge in the entire furnace circumferential direction (S110).

The coke ratio calculation unit 722 calculates the volumes of the coke layer and the ore layer contained in the tuyere region Q for each tuyere region Q based on the acquired sedimentary shape A obtained in S110 (S120).

The coke ratio calculation unit 722 includes the volume of the coke layer and the ore layer in each tuyere region Q obtained in S120, and the bulk density of each brand contained in the coke layer and the ore layer read from the bulk density DB711. And, are used to calculate the mass of coke and the mass of the ore raw material contained in each tuyere region Q (S130).

The coke ratio calculation unit 722 calculates the O / C ratio in each tuyere region based on the mass of coke contained in each tuyere region and the mass of the ore raw material calculated in S130 (S140).

The coke ratio calculation unit 722 divides the ore ratio read from the ore ratio DB712 by the O / C ratio in each tuyere region calculated in S140, and is included in each tuyere region based on the calculation result. The coke ratio of coke is calculated (S150).

Based on the coke ratio of coke contained in each tuyere region calculated in S150, the pulverized coal ratio calculation unit 723 calculates the pulverized coal ratio to be blown into each tuyere region (S160). The pulverized coal ratio blown into each tuyere region is calculated so that the reducing agent ratio in each tuyere region is equal.

The descent estimation unit 724 estimates that the sedimentary layer to be acquired has descended to the reference position (S170).

When the descent estimation unit 724 estimated that the acquisition target sedimentary layer had descended to the reference position (S170), the pulverized coal amount control unit 725 was calculated for each tuyere region by the pulverized coal ratio calculation unit 723. The pulverized coal is blown into the blast furnace from the tuyere at the pulverized coal ratio (S160) to be blown. (S180).

(Modification example)
As described above, in the first embodiment, the coke ratio of each tuyere region is calculated from the acquired deposited shape, and the coke ratio is subtracted from the target reducing agent ratio so that the reducing agent ratio in each tuyere region becomes equal. Although the ratio was calculated, the following modified examples can be considered as a method for calculating the pulverized coal ratio blown into each tuyere region.
That is, the mass ratio (O / C ratio) of the ore raw material to the coke in each tuyere region Q is calculated from the acquired sedimentary shape by the same procedure as in the above-mentioned (a) to (c). O / C relative ratio (relative) of each tuyere region by dividing the O / C ratio of each tuyere region by the average O / C ratio (or preset O / C ratio) of the entire tuyere region. O / C) can be obtained. Here, the calculation method of the "average O / C ratio of the entire tuyere region" is not particularly limited, but for example, the calculated value obtained by arithmetically averaging the O / C ratio of each tuyere region or the median value can be used. can. The "set O / C ratio" can be obtained from, for example, the operation results.

At this time, the relative O / C = 1.1 in one tuyere region Q and the relative O / C = 0.9 in another tuyere region Q, so that the feather with a high relative O / C It is desired to increase the pulverized coal ratio in the mouth region Q and decrease the pulverized coal ratio in the tuyere region Q having a low relative O / C. Therefore, by multiplying the preset pulverized coal ratio (mass of pulverized coal required to produce 1 ton of hot metal) by the relative O / C in each tuyere region Q, the reducing agent ratio in each tuyere region is increased. Variation can be suppressed.

As described above, the pulverized coal ratio to be blown into each tuyere region Q can be calculated by multiplying the preset pulverized coal ratio by the O / C relative ratio in each tuyere region Q, and the sedimentary layer to be acquired is desired. When it is estimated that the blast furnace has descended to the reference position of, pulverized coal can be blown into the blast furnace from each tuyere at the pulverized coal ratio.

Each function constituting the above-mentioned pulverized coal injection control device 7 can be realized by a program, a computer program prepared in advance for realizing each function is stored in the auxiliary storage device, and a control unit such as a CPU assists. The functions of each unit can be operated by reading the program stored in the storage device into the main storage device and executing the program read into the main storage device by the control unit.

Further, the program can be provided to a computer (for example, a server) in a state of being recorded on a computer-readable recording medium. Computer-readable recording media include optical discs such as CD-ROMs, phase-changing optical discs such as DVD-ROMs, magneto-optical discs such as MO (Magnet Optical) and MD (Mini Disk), floppy (registered trademark) discs, and the like. Examples include magnetic disks such as removable hard disks, compact flash (registered trademark), smart media, SD memory cards, and memory cards such as memory sticks. Further, a hardware device such as an integrated circuit (IC chip or the like) specially designed and configured for the purpose of the present invention is also included as a recording medium.

1: Blast furnace 2: tuyere 7: pulverized coal injection control device 721: deposit shape acquisition unit 722: coke ratio calculation unit 723: pulverized coal ratio calculation unit 724: descent estimation unit 725: pulverized coal amount control unit

Claims (10)

It is a method of operating a blast furnace that charges ore raw materials and coke into the furnace.
A sedimentary shape acquisition step of acquiring the sedimentary shape of the ore layer and coke layer deposited in the blast furnace for at least one charge over the entire furnace circumferential direction.
Based on the sedimentary shape of the coke layer and the ore layer obtained in the sedimentary shape acquisition step, the coke ratio of coke contained in each tuyere region of the furnace height direction fan type corresponding to one or more tuyere is calculated. Coke ratio calculation step and
Based on the coke ratio of coke contained in each tuyere region calculated in the coke ratio calculation step, the pulverized coal ratio blown into each tuyere region so that the reducing agent ratio in each tuyere region becomes equal. And the pulverized coal ratio calculation step to calculate
A descent estimation step for estimating that the ore layer and the coke layer for which the sedimentary shape has been acquired in the sedimentary shape acquisition step has descended to a desired reference position, and a descent estimation step.
When it is estimated that the ore layer and the coke layer whose accumulated shape has been acquired in the accumulated shape acquisition step have descended to the reference position, the fine powder to be blown into each tuyere region calculated in the pulverized coal ratio calculation step. With the coal ratio, the pulverized coal amount control step of blowing pulverized coal into the blast furnace from each tuyere,
A method of operating a blast furnace, which is characterized by being equipped with. In the sedimentary shape acquisition step, the sedimentary shapes are measured in a plurality of furnace radial directions using a two-dimensional profile meter, and the unmeasured sedimentary shapes in the furnace radial direction are interpolated using the measured sedimentary shapes. The method for operating a blast furnace according to claim 1, wherein the deposited shape of the ore layer and the coke layer deposited in the blast furnace is acquired. The method for operating a blast furnace according to claim 1, wherein in the step of acquiring the deposited shape, the deposited shapes of the ore layer and the coke layer deposited in the blast furnace are acquired by using a three-dimensional profile meter. Each tuyere area is
Any one of claims 1 to 3, characterized in that it has a fan-shaped shape with 360 ° / number of tuyere as a central angle in the direction of furnace height and is formed line-symmetrically with respect to the axis of the tuyere. The operation method of the blast furnace described in one. The coke ratio calculation step is
A volume calculation step for calculating the volume of the coke layer and the ore layer contained in each tuyere region based on the sedimentary shape of the coke layer and the ore layer obtained in the sedimentary shape acquisition step.
Each tuyere region using the volume of the coke layer and the ore layer included in each tuyere region and the bulk density of each brand contained in the coke layer and the ore layer calculated in the volume calculation step. A mass calculation step for calculating the mass of coke and the mass of the ore raw material contained in
Based on the mass of coke contained in each tuyere region and the mass of ore raw material calculated in the mass calculation step, the mass ratio (O / C ratio) of the ore raw material to the coke in each tuyere region is calculated. O / C ratio calculation step to be performed and
Using at least a preset ore ratio and an O / C ratio in each tuyere region calculated in the O / C ratio calculation step, the coke ratio of coke contained in each tuyere region is determined. Steps to calculate and
The method for operating a blast furnace according to any one of claims 1 to 4, wherein the blast furnace is provided. In the pulverized coal ratio calculation step, the coke ratio of coke contained in each tuyere region calculated in the coke ratio calculation step is subtracted from the target reducing material ratio common to all the tuyere regions to obtain the above. The method for operating a blast furnace according to any one of claims 1 to 5, wherein the ratio of pulverized coal blown into each tuyere region is calculated. The method for operating a blast furnace according to any one of claims 1 to 6, wherein the reference position is set in a region from the apex of the estimated fusion zone to the tuyere height. It is a method of operating a blast furnace that charges ore raw materials and coke into the furnace.
A sedimentary shape acquisition step of acquiring the sedimentary shape of the ore layer and coke layer deposited in the blast furnace for at least one charge over the entire furnace circumferential direction.
Based on the sedimentary shape of the coke layer and the ore layer obtained in the sedimentary shape acquisition step, the volume of the coke layer and the ore layer included in each tuyere region of the furnace height direction fan type corresponding to one or more tuyere. And the volume calculation step to calculate
Each tuyere region using the volume of the coke layer and the ore layer included in each tuyere region and the bulk density of each brand contained in the coke layer and the ore layer calculated in the volume calculation step. A mass calculation step for calculating the mass of coke and the mass of the ore raw material contained in
Based on the mass of coke contained in each tuyere region and the mass of ore raw material calculated in the mass calculation step, the mass ratio (O / C ratio) of the ore raw material to the coke in each tuyere region is calculated. O / C ratio calculation step to be performed and
By dividing the O / C ratio in each tuyere region calculated in the O / C ratio calculation step by the average O / C ratio of the entire tuyere region or the preset O / C ratio. The O / C relative ratio calculation step for obtaining the O / C relative ratio of each tuyere region, and
The pulverized coal ratio set in advance is multiplied by the O / C relative ratio in each tuyere region calculated in the O / C relative ratio calculation step to calculate the pulverized coal ratio to be blown into each tuyere region. Coal ratio calculation step and
A descent estimation step for estimating that the ore layer and the coke layer for which the sedimentary shape has been acquired in the sedimentary shape acquisition step has descended to a desired reference position, and a descent estimation step.
When it is estimated that the ore layer and the coke layer whose accumulated shape has been acquired in the accumulated shape acquisition step have descended to the reference position, the fine powder to be blown into each tuyere region calculated in the pulverized coal ratio calculation step. With the coal ratio, the pulverized coal amount control step of blowing pulverized coal into the blast furnace from each tuyere,
A method of operating a blast furnace, which is characterized by being equipped with. A pulverized coal injection control device used in a blast furnace that charges ore raw materials and coke into the furnace.
A sedimentary shape acquisition unit that acquires the sedimentary shape of the ore layer and coke layer deposited in the blast furnace for at least one charge over the entire furnace circumference direction.
Based on the sedimentary shape of the coke layer and the ore layer obtained by the sedimentary shape acquisition unit, the coke ratio of coke contained in each tuyere region of the furnace height direction fan type corresponding to one or more tuyere is calculated. Coke ratio calculation unit and
Based on the coke ratio of coke contained in each tuyere region calculated by the coke ratio calculation unit, the pulverized coal ratio blown into each tuyere region so that the reducing agent ratio in each tuyere region becomes equal. The pulverized coal ratio calculation unit that calculates
A descent estimation unit that estimates that the ore layer and coke layer whose deposit shape has been acquired by the sediment shape acquisition unit has descended to a desired reference position, and a descent estimation unit.
Each wing calculated by the pulverized coal ratio calculation unit when the descent estimation unit estimates that the ore layer and the coke layer whose deposit shape has been acquired by the deposit shape acquisition unit have descended to the reference position. A pulverized coal amount control unit that blows pulverized coal into the blast furnace from each tuyere at the ratio of pulverized coal blown into the mouth area.
A pulverized coal injection control device characterized by being provided with. On the computer
A sedimentary shape acquisition step of acquiring the sedimentary shape of the ore layer and coke layer deposited in the blast furnace for at least one charge over the entire furnace circumferential direction.
Based on the sedimentary shape of the coke layer and the ore layer obtained in the sedimentary shape acquisition step, the coke ratio of coke contained in each tuyere region of the furnace height direction fan type corresponding to one or more tuyere is calculated. Coke ratio calculation step and
Based on the coke ratio of coke contained in each tuyere region calculated in the coke ratio calculation step, the pulverized coal ratio blown into each tuyere region so that the reducing agent ratio in each tuyere region becomes equal. And the pulverized coal ratio calculation step to calculate
A descent estimation step for estimating that the ore layer and the coke layer for which the sedimentary shape has been acquired in the sedimentary shape acquisition step has descended to a desired reference position, and a descent estimation step.
Each of the feathers calculated in the pulverized coal ratio calculation step when the descent estimation step estimates that the ore layer and the coke layer whose deposit shape was acquired in the deposit shape acquisition step has descended to the reference position. A pulverized coal amount control step in which pulverized coal is blown into the blast furnace from each tuyere by the ratio of pulverized coal blown into the mouth area.
A pulverized coal injection control program characterized by executing.

Images