JP6405877B2 - Raw material charging method for bell-less blast furnace - Google Patents

Description

  The present invention relates to a raw material charging method for a bell-less blast furnace. In particular, the present invention relates to a method of charging coke into an inside of a blast furnace while mixing coke with ore raw materials such as sintered ore, pellets, and lump ore in a furnace top hopper.

In the steel industry, the amount of carbon dioxide, which is one of the greenhouse gases, is high, so there is a need to reduce that amount. Therefore, for the purpose of reducing carbon dioxide emissions, an operation (low coke ratio operation) for reducing the ratio of coke used as raw material for pig iron production is performed.
Usually, a blast furnace uses pig iron ore raw materials such as sintered ore, pellets, ores, and coke obtained by carbonizing coal to produce pig iron by charging each of the ore raw material and coke in layers. Yes.
Coke plays various roles in the blast furnace, such as a reducing material, a heat source in the blast furnace, and a spacer for ensuring ventilation. If low coke ratio operation is carried out, the amount of coke that plays the above role will decrease. In this case, there is a concern that problems such as delay of the reduction reaction, lack of heat, and deterioration of air permeability may occur. Among these, deterioration of air permeability at the lower part of the furnace is a particular problem. This is considered to be because the ore melting part at the bottom of the furnace has the highest ventilation resistance.

Therefore, in order to improve the air permeability, a method of mixing coke into the ore layer in which coke is mixed with the ore layer has been proposed. Here, coke is mixed in the ore layer for the purpose of providing a role as a spacer for ensuring ventilation.
On the other hand, there are differences in density, particle size, shape, and the like between ore and coke. For this reason, coke mixing charging into the ore layer has a problem that segregation and separation of coke occur in the transport equipment before charging into the blast furnace.

The following technologies have been proposed for charging coke into the ore layer.
A method of charging raw materials in a state in which coke is stacked within 50% of the leading side charged in the furnace top bunker with respect to the conveying direction length of the ore raw materials on the charging belt conveyor is disclosed. (See Patent Document 1).
In addition, when ores and coke respectively held in two furnace top bunkers are charged into the furnace at the same time, when the amount of coke charged for one batch is 5 to 50% by mass, the ore is simultaneously cut out. In addition, it is described that the central charging of coke and the mixed charging of ore and coke are performed in one batch (see Patent Document 2).

  Furthermore, as a technology for charging charges with different particle sizes, a collision plate provided at the upper part of the hopper and arranged so that all of the raw material falling into the hopper when the raw material is charged hits the lower part of the hopper The adjustment apparatus of the time-sequential discharge | emission particle size characteristic from a hopper provided with the baffle plate which can be provided in 1 and can change the flow pattern at the time of raw material discharge | emission is described (refer patent document 3). According to Patent Document 3, the raw material particle size at the time of discharging from the hopper can be controlled.

Japanese Patent No. 5338308 Japanese Patent No. 4269847 No. 08-350

However, in Patent Document 1, it is possible to make the radial distribution of the mixing ratio of the coke after charging into the furnace top hopper more uniform, but the coke segregates when charged into the furnace. Therefore, it is not always possible to effectively form the mixed layer.
Moreover, in the said patent document 2, it does not respond | correspond to problems, such as segregation at the time of carrying out mixing charging of ores and coke.
Moreover, in the said patent document 3, the particle size in one kind of raw material of coke or ore is made into object, and the charging method of the mixture which mixed both is not mentioned.

  When charging coke into the ore layer, even if uniform mixing is performed in the raw material hopper at the top of the furnace, when the raw material hopper is charged into the furnace, the raw material is segregated or deposited in the furnace radial direction. Sometimes segregates. For this reason, in order to make a mixed layer uniformly in the furnace, it is not optimal to make uniform when the raw material hopper is charged at the top of the furnace. For this reason, it was necessary to control the mixing rate at the top of the furnace.

  An object of the present invention is to provide a raw material charging method for a bell-less blast furnace capable of controlling a change over time in the ratio of coke in a mixture of ore and coke in mixing charging of coke into an ore layer. is there.

The present inventor installed a baffle plate in the hopper and charged the coke mixture into the ore layer, and changed the angle of the baffle plate to change the ratio of coke in the mixture of ore and coke over time. The present invention has been completed by finding that it can be controlled. The present invention is based on such knowledge.
(1) In a raw material charging method for a bell-less blast furnace having an auxiliary raw material hopper in addition to the main raw material hopper at the top of the furnace, the mixture of ore and coke is charged into the auxiliary raw material hopper, and the mixture is charged to the charging belt. When the ore and the coke are cut out on a conveyor, the coke is layered on the ore, and the auxiliary raw material hopper is a flat plate and has one movable plate having a movable shaft. The rectifying plate has the flat plate facing the raw material charging direction from the charging belt conveyor, and the auxiliary raw material hopper is located on the near side of the raw material charging direction with respect to the rectifying plate. It is installed so as to be divided into a first region and a second region located on the back side in the raw material charging direction with respect to the rectifying plate, and is located above the movable shaft of the rectifying plate. Part of the mixture During the free fall into the auxiliary material hopper from the charging belt conveyor, the charging position of the coke in the mixture into the auxiliary material hopper is determined by bisecting the trajectory of the mixture. A portion of the rectifying plate below the movable shaft is above the discharge port of the auxiliary raw material hopper, and the first discharge flow path through which the charge charged in the first region passes and Forming a second discharge flow path through which the charge charged in the second region passes, and charging from either the first discharge flow path or the second discharge flow path In order to obtain a desired change with time in the ratio of the coke in the mixture discharged from the auxiliary raw material hopper by changing the angle of the flow straightening plate , the flow straightening is performed. Japanese to be predetermined angles of the plate Raw material charging method of bell-less blast furnace to be.
(2) When the coke is laminated in layers on the ore on the charging belt conveyor, the coke is laminated within 50% of the total lamination length on the charging belt conveyor. The raw material charging method for the bell-less blast furnace according to (1), wherein:
(3) 4 batch charging carried out in the order of Cc, C ₁ , O ₁ , O ₂ , and when charging the mixture into O ₁ , the total discharge time from the auxiliary raw material hopper, The raw material charging method for the bell-less blast furnace according to (1) or (2), wherein the amount of coke discharged in the first 50% discharge time is increased.
(4) 4 batch charging performed in the order of Cc, C ₁ , O ₁ , O ₂ , and when charging the mixture into the O ₁ , the total discharge time from the auxiliary raw material hopper, The raw material charging method for a bell-less blast furnace according to (1) or (2), wherein the amount of coke discharged in the second half 50% discharge time is increased.

  According to the present invention, by installing a baffle plate in the hopper and changing the angle of the baffle plate, in the coke mixing charging into the ore layer, the change with time of the coke ratio in the mixture is controlled. Can do.

_Cc, schematic view of a charge distribution in the C _{1, O 1,} O ₂ charged. The figure which shows the relationship between a baffle plate and the fall locus | trajectory at the time of raw material charging. Schematic of a model experiment apparatus. The figure which shows the shape of an auxiliary material hopper. The figure which shows the state which installed the baffle plate in the auxiliary material hopper. It is a figure explaining the cutting-out conditions of a raw material, (A) is uniform overlap, (B) is the front half 1/2 overlap, (C) is the middle board 1/2 overlap, (D) is the latter half 1/2 overlap. The figure explaining the sampling method of a raw material. The figure which shows the discharge rate ratio of the coke discharged | emitted from an auxiliary material hopper when raw material cut-out is made uniform. The figure which shows the discharge | emission rate ratio of the coke discharged | emitted from an auxiliary material hopper when raw material cut-out is made into the first half lap. The figure which shows the discharge rate ratio of the coke discharged | emitted from an auxiliary raw material hopper when raw material cut is made into the middle board | substrate 1/2 overlap. The figure which shows the discharge rate ratio of the coke discharged | emitted from an auxiliary raw material hopper when raw material cut-out is made into 1/2 halves. The figure explaining the mixing condition when the current plate is inclined to the plus side in Cc, C ₁ , O ₁ , O ₂ charging. _Cc, at C _{1, O 1,} O ₂ loading a diagram for explaining the mixing conditions when tilting the current plate to the minus side.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The raw material charging method of the bell-less blast furnace in the present embodiment is the same as the raw material charging method of the bell-less blast furnace having the auxiliary raw material hopper in addition to the main raw material hopper at the top of the furnace, and the mixture of ore and coke is charged in the auxiliary raw material hopper. The mixture is formed by laminating the coke on the ore when the ore and the coke are cut out on a charging belt conveyor, and the auxiliary material hopper has a movable shaft. A flow path of the mixture while the mixture freely falls from the charging belt conveyor into the auxiliary raw material hopper at a portion above the movable shaft of the current plate. Is divided into two, the charging position of the coke in the mixture into the auxiliary material hopper is determined, and the portion of the rectifying plate below the movable shaft is located on the auxiliary shaft. By forming two discharge passages having a predetermined cross-sectional area ratio between the end portion of the lower portion of the current plate and the both side surfaces of the auxiliary material hopper at the upper portion of the discharge port of the material hopper, The flow rate of each of the mixture passing through the two discharge flow paths is determined, and the ratio of the coke in the mixture discharged from the auxiliary raw material hopper is changed by changing the angle of the rectifying plate. It is characterized by controlling changes over time.

The auxiliary material hopper is usually used for charging coke into the furnace center. In this embodiment, this auxiliary raw material hopper is used not only for charging coke into the furnace center but also for charging coke in which a mixture of ore and coke is charged.
As the coke used for the coke mixing charging, it is preferable to use lump coke having an average particle size of 5 times or more with respect to the average particle size of the ore. Since the particle size segregation becomes more remarkable as the particle size ratio is larger, the effect of the present invention is easily obtained.

The raw material charging method of this embodiment is suitable for 4-batch charging in which Cc, C ₁ , O ₁ , and O ₂ are charged in this order. Among these, C ₁ and O ₂ are charging from the main raw material hopper, and Cc and O ₁ are charging from the auxiliary raw material hopper.
Specifically, in the Cc batch, coke is charged and a coke layer is formed in the center of the furnace. Then, the C ₁ batch was charged with coke, and horizontal terrace substantially horizontal shaped furnace wall portion, further, sloping coke inclined from the furnace inner end of the horizontal terrace downwardly toward the furnace center portion Form a layer. Next, in the O ₁ batch, an ore and coke mixture is charged, and an ore and coke mixture layer is formed on the horizontal terrace of the C ₁ batch. Finally, in the O ₂ batch, the ore is charged, a horizontal terrace having a substantially horizontal shape on the furnace wall side, and a slope inclined downward from the inner tip of the horizontal terrace toward the furnace center. Form an ore layer.
FIG. 1 shows a schematic diagram of the charge distribution in the Cc, C ₁ , O ₁ , O ₂ charge.

<Charging the mixture of ore and coke into the auxiliary hopper 1>
Hereinafter, the raw material charging from the main raw material hopper of C ₁ and O _{2 and} the raw material charging from the auxiliary raw material hopper of Cc are omitted because they are the same as before, and the ore and coke into the auxiliary raw material hopper of O ₁ are omitted. The charging of the mixture will be explained.
As shown in FIG. 2, one rectifying plate 2 having a movable shaft 3 is installed inside the auxiliary raw material hopper 1. Here, the end 2A of the upper portion of the current plate 2 is placed at a position that bisects the free-falling raw material. Moreover, it is preferable to match the height of the end portion 2A of the upper portion of the current plate 2 with the height of the deposition surface formed when all the raw materials of the batch are charged. Further, the total amount of raw materials of the batch is preferably within 1.1 times the volume where the deposition surface coincides with the end 2A of the upper portion of the rectifying plate 2. Thereby, coke classification described below can be sufficiently performed.
First, when ore and coke are cut out, the mixture is formed by laminating coke on the ore on the charging belt conveyor immediately before the furnace top hopper.
And the mixture laminated | stacked on the said layer shape is dropped from a charging belt conveyor, and a mixture is charged into the auxiliary material hopper 1. FIG. The mixture dropped from the charging belt conveyor collides with a portion above the movable shaft 3 of the rectifying plate 2 while drawing a parabolic fall locus indicated by an arrow in FIG. Here, in the collision between the rectifying plate 2 and the mixture, the installation position of the rectifying plate 2 and the inclination angle of the rectifying plate 2 are adjusted so that about 80% of the falling mixture collides with the rectifying plate 2. It is preferable. The mixture is a region in which most of the coke having a large average particle size and a small density is located on the back side of the current plate 2 as viewed from the charging belt conveyor side due to the collision with the current plate 2 (in FIG. 2). In the right side of the current plate 2). Further, the probability that finer ore than coke is charged in the region located on the front side of the current plate 2 (the region on the left side of the current plate 2 in FIG. 2) when viewed from the charging belt conveyor side. Is expensive.
As a result, the mixture is divided into two parts with the current plate 2 in between, and the charge shown in FIG. Are charged respectively. Hereinafter, the mixture charged in the auxiliary raw material hopper 1 will be described as a charged material.

<Discharge of charge from auxiliary material hopper 1>
Then, when discharging the charged material from the auxiliary material hopper 1, first, the material charged in the region C near the discharge port of the auxiliary material hopper 1 is discharged first. Next, what is discharged is affected by the position of the portion below the movable shaft 3 of the rectifying plate 2.
The current plate 2 divides the auxiliary material hopper 1 into two regions above the discharge port of the auxiliary material hopper 1. The area partitioned here is an area excluding the area C. Two discharge passages having a predetermined cross-sectional area ratio are formed between the end portion of the rectifying plate 2 below the movable shaft 3 and both side surfaces of the auxiliary raw material hopper 1. Of the two discharge channels, one discharge channel is a discharge channel in region A, and the other discharge channel is a discharge channel in region B.
As shown in FIG. 2, when the portion above the movable shaft 3 of the rectifying plate 2 is in a state in which the rectifying plate 2 is tilted away from the charging belt conveyor, the portion of the rectifying plate 2 is higher than the movable shaft 3 of the rectifying plate 2. The lower part is located in a state close to the charging belt conveyor side. For this reason, the ratio of the cross-sectional area reaching the discharge port is larger in the discharge flow path in the region B than in the discharge flow path in the region A. Thereby, each flow volume of the charge which passes two discharge flow paths is determined. Therefore, the charge on the right side of the hopper shown in FIG. In addition, since the ore having a high density is to be discharged at the same time, the ore having a high density and the coke are discharged while being mixed. Finally, the charge on the left side of the hopper, in which a large amount of ore in region A has accumulated, is discharged. Thus, by setting the rectifying plate 2 to be in a state in which the portion above the movable shaft 3 of the rectifying plate 2 is away from the charging belt conveyor, the total discharge time from the auxiliary material hopper 1 is reduced. The amount of coke discharged during the first 50% discharge time can be increased.

  The charge discharged from the auxiliary raw material hopper 1 is charged into the furnace with a forward tilt through a turning chute. For this reason, a mixed layer is formed in the furnace wall part side by discharging | emitting preferentially, mixing a high density ore and coke in the discharge | emission first stage. Then, fine ore is discharged at a later stage of discharge, and the fine ore enters so as to penetrate into the voids in the mixed layer. Thereby, it is possible to form a mixed layer in which coke and ore are further mixed.

On the other hand, when the rectifying plate 2 is inclined in a direction in which the portion above the movable shaft 3 of the rectifying plate 2 approaches the charging belt conveyor, the portion below the movable shaft 3 of the rectifying plate 2 is It is located away from the charging belt conveyor. For this reason, the ratio of the cross-sectional area reaching the discharge port is larger in the discharge channel in the region A than in the discharge channel in the region B. Therefore, the charge on the left side of the hopper in FIG. Finally, the charge on the right side of the hopper where a large amount of coke in the region B is accumulated is discharged. Thus, by setting the current plate 2 to be inclined so that the portion above the movable shaft 3 of the current plate 2 approaches the charging belt conveyor, the total discharge time from the auxiliary material hopper 1 can be reduced. The amount of coke discharged in the second half 50% discharge time can be increased.
In addition, the ore is discharged preferentially in the first discharge period, and the mixed layer is formed by discharging the ore and coke while mixing in the second discharge period.

<Control of change in coke ratio over time>
Changes in the ratio of coke in the charge from the auxiliary raw material hopper 1 over time by changing the angle of the current plate 2 due to the action at the time of charging and discharging the mixture (time of the coke ratio in the mixture) Transition) can be controlled.

<Utilization for blast furnace operation>
It is difficult to change the angle of the current plate 2 during a period in which the charged material (the charged mixture) exists in the auxiliary raw material hopper 1. Therefore, the angle of the current plate 2 is the same between the charging of the mixture into the auxiliary raw material hopper 1 and the discharge of the charged material from the auxiliary raw material hopper 1, and the ratio of the current of the current plate 2 and the ratio of coke is changed over time. The change is predetermined.
The angle of the current plate 2 is controlled as follows according to the blast furnace operation. For example, in order to improve the ventilation on the furnace wall side, the portion of the rectifying plate 2 above the movable shaft 3 tilts the rectifying plate 2 in a direction away from the charging belt conveyor. Thereby, lump coke is deposited on the furnace wall side. On the other hand, when improving ventilation at the center of the furnace, the rectifying plate 2 is tilted in such a direction that the portion above the movable shaft 3 of the rectifying plate 2 approaches the charging belt conveyor. Then, by loading the lump coke into the shoulder of the horizontal terrace formed by C batch, the lump coke charged in the shoulder of the horizontal terrace in the next O ₂ batch is collapsed to the center of the furnace.

Next, the present invention will be described in more detail with reference to examples. And it shows concretely based on an experimental result that the time-dependent change of the ratio of the coke in a charging material can be controlled by changing the angle of a baffle plate. In addition, this invention is not restrict | limited to the description content of these Examples at all.
<Example 1>
In the 1 / 5.2 model experiment shown in FIG. 3, the coke discharge behavior in the coke mixing charging into the ore layer was examined. In addition, in the model experiment apparatus shown in FIG. 3, the code | symbol 10 is an auxiliary material hopper, and the code | symbol 20 is a charging belt conveyor.
<Sub-material hopper>
The auxiliary material hopper used in this example will be described with reference to FIG. 4 shows a top view of the auxiliary material hopper, and FIG. 4 shows a side view of the auxiliary material hopper.
The auxiliary raw material hopper 10 includes a raw material charging portion 11, a tapered portion 12, and a raw material discharge portion 13.
The raw material charging unit 11 is located above the auxiliary raw material hopper 10. Moreover, the shape is substantially cylindrical. The inner diameter of the upper end and the lower end of the raw material charging part 11 is 690 mm, and the vertical height of the raw material charging part 11 is 430 mm.
The tapered portion 12 is located in the center portion of the auxiliary raw material hopper 10. Moreover, the shape is an inverted frustum cylinder shape. The upper end of the tapered portion 12 is connected to the lower end of the raw material charging portion 11. In addition, the lower end of the tapered portion 12 is provided with a central axis in a direction away from the charging belt conveyor rather than the central axis of the upper end of the tapered portion 12. Moreover, the lower end of the taper part 12 is provided so that the outer periphery may be in a position in contact with the central axis of the raw material charging part 11. The inner diameter of the lower end of the tapered portion 12 is 240 mm, and the vertical height of the tapered portion 12 is 370 mm.

  The raw material discharge unit 13 is located below the auxiliary raw material hopper 10. The upper end of the raw material discharge part 13 is connected to the lower end of the taper part 12. The lower end of the raw material discharge unit 13 is provided with a central axis in a direction closer to the charging belt conveyor than the central axis of the upper end of the raw material discharge unit 13. The lower end of the raw material discharge part 13 is provided so that the outer periphery may be in a position in contact with the central axis of the raw material charging part 11. The lower end of the raw material discharge unit 13 has an inner diameter that is smaller than the inner diameter of the upper end of the raw material discharge unit 13. The inner diameter dimension of the lower end of the raw material discharge part 13 is 140 mm, and the vertical height of the raw material discharge part 13 is 250 mm. Note that the lower end of the material discharge unit 13 corresponds to the discharge port 14 of the auxiliary material hopper 10, and the discharge port 14 is provided with a gate 15 that can be opened and closed.

FIG. 5 is a view showing a state in which the current plate 16 is installed in the auxiliary raw material hopper 10. 5A is a cross-sectional view of the auxiliary raw material hopper 10 on which the current plate 16 is installed, and FIG. 5B is a view of the inclined current plate 16 viewed from the upper side of the auxiliary raw material hopper 10. is there.
As shown in FIG. 5B, the rectifying plate 16 is a trapezoidal flat plate, the length of the upper base is 580 mm, the length of the lower base is 400 mm, and the height is 250 mm. The rectifying plate 16 has a movable shaft 17 parallel to the upper and lower bases. The movable shaft 17 is provided at a position having a height of 80 mm from the lower base to the upper base (position having a height of 170 mm from the upper base to the lower base).
As shown in FIG. 5A, the rectifying plate 16 is installed such that the flat plate faces the raw material charging direction from the charging belt conveyor. The movable shaft 17 is located 20 mm closer to the charging belt conveyor side from the central axis at the lower end of the tapered portion 12, and 250 mm in the vertical direction from the lower end of the tapered portion 12 toward the upper end of the tapered portion 12. It is installed at the height of
The rectifying plate 16 is configured to be tiltable about the movable shaft 17 as an axis.

In the present embodiment, inclining the rectifying plate 16 so that the upper side of the rectifying plate 16 above the movable shaft 17 approaches the charging belt conveyor is referred to as a minus-side inclination. Further, inclining the rectifying plate 16 in a direction in which the upper side of the rectifying plate 16 above the movable shaft 17 is away from the charging belt conveyor is referred to as plus side inclination.
In the auxiliary material hopper 10 configured as described above, when the rectifying plate 16 is inclined 15 ° to the plus side, the upper end of the rectifying plate 16 is equal to the height of the connection position between the raw material charging portion 11 and the tapered portion 12. They are arranged so that they almost match. In this embodiment, the rectifying plate 16 is inclined at a minus side inclination of 15 ° and a plus side inclination of 30 °. When inclined by 30 ° to the plus side, about 80% of the fall width of the mixture falling from the charging belt conveyor 20 collides with the current plate 16.

<Raw material cutting>
Regarding the mixture charged into the auxiliary raw material hopper 10, when mixing the coke with the ore raw material on the charging belt conveyor 20, the cut length of the mixed coke laminated on the ore raw material is changed to the following four patterns. The experiment was conducted. In addition, the coke used the block coke 5 times or more with respect to an ore particle size.
FIG. 6 shows the conditions of the raw material cutting method. 6A is a uniform stack, FIG. 6B is a half stack of the first half, FIG. 6C is a 1/2 stack of the middle board, and FIG. 6D is a half stack of the second half.
・ Uniform lamination: Coke is uniformly laminated on the ore with the same length.
-First half lap: Coke is laminated 50% from the top with respect to the total lamination length.
-Middle layer 1/2 stacking: 50% of coke is stacked from the middle layer to the total stacking length.
-Second half 1/2 stack: Coke is stacked at 50% of the second half with respect to the total stack length.

Moreover, the following three patterns were employ | adopted for the structure of the auxiliary raw material hopper 10. As shown in FIG.
-No rectifying plate 16 is installed in the auxiliary material hopper 10.
-The rectifying plate 16 is installed in the auxiliary material hopper 10, and the rectifying plate 16 is inclined to the plus side. The inclination angle is plus 30 ° with respect to the axial position of the current plate 16.
-A rectifying plate 16 is installed in the auxiliary raw material hopper 10, and the rectifying plate 16 is inclined to the minus side. The inclination angle is minus 15 ° with respect to the axial position of the current plate 16.

  Moreover, as shown in FIG. 7, the belt conveyor 21 was installed in the lower part of the auxiliary material hopper 10, the some sampling box 22 was provided on this belt conveyor 21, and it was set as the structure which sends out the sampling box 22 according to raw material cutting. Then, the charged material (mixed material) is discharged from the auxiliary raw material hopper 10 and charged into the sampling box 22 on the belt conveyor 21 to investigate changes in the mass ratio of coke and ore in the mixed material over time. did. The obtained results are shown in FIGS.

<Rectifying plate plus slope>
As apparent from FIGS. 8 to 11, when the rectifying plate 16 is mixed and charged while being inclined to the plus side, the material is cut out regardless of the patterns (1) to (4) described above. It can be confirmed that a large amount of coke is discharged in the dimensionless discharge time of 0.2 to 0.4 in the previous period.
This is because, in the region B located on the right side of the auxiliary raw material hopper 1 shown in FIG. 2, the bulk coke having a large particle size and a small density is segregated and charged when discharged from the auxiliary raw material hopper 1. This is presumed to be the result of preferential discharge of the bulk coke from the segregated charge.

As shown in FIG. 12, in Cc, C ₁ , O ₁ , and O ₂ charging, the ore layer thickness is increased in the region from the furnace wall to the middle between the furnace center and the furnace wall. There are many. In this case, it is preferable to perform the O ₁ batch charging with the rectifying plate 16 inclined to the plus side. In the mixed charging in which the rectifying plate 16 is inclined to the plus side, a large amount of coke is discharged in the previous discharge period. Since it is discharged from the turning chute with a forward tilt, the segregated lump coke is charged into the region on the furnace wall side indicated by the dotted circle in FIG. Thus, the above charging method can improve the reducibility and improve the air permeability of the lower part of the furnace.

<Rectifying plate minus slope>
On the other hand, as apparent from FIGS. 8 to 11, when the rectifying plate 16 is mixed and charged while being inclined to the minus side, the lump coke is produced in the dimensionless discharge time 0.6 to 1.0 in the latter discharge stage. It can be confirmed that a lot is discharged.
This is because, when discharging the raw material from the auxiliary raw material hopper 1 shown in FIG. 2, the rectifying plate 2 is inclined to the negative side so that the ore having a small particle size and a high density is formed in the region A located on the left side of the hopper. Is presumed to be the result of preferential discharge of the charge in the region A in which the fine ore is segregated and charged at the time of discharge from the auxiliary raw material hopper 1.

In the blast furnace 4 dump operation, when the low coke ratio operation is performed on the blast furnace charged with Cc, C ₁ , O ₁ , and O ₂ , the coke layer in the region corresponding to the base of Cc indicated by the dotted circle in FIG. The layer thickness tends to be thin. The area where the thickness of the coke layer is thin has poor air permeability. In this case, it is preferable to carry out the O ₁ batch charging with the current plate 16 inclined to the negative side. In the mixed charging in which the rectifying plate 16 is inclined to the minus side, the mass coke that has been segregated and charged in the late discharge is charged. Since the discharging chute is discharged from the turning chute, the segregated lump coke is discharged into a region A indicated by a dotted circle in FIG. 13 on the O ₁ batch furnace side.
Then, through the crowded breaking the O ₁ batch O ₂ batches of instrumentation Nyutoki, the polarization析装input has been lump coke in O ₁ batch can be poured into the furnace center portion. As a result, a large amount of coke can be charged in the region B indicated by the solid circle in FIG. 13 where the thickness of the coke layer is thin, so that improvement in air permeability can be expected.
In this way, by charging the raw material while the current plate 16 is inclined at a desired angle, it is possible to control the change with time of the ratio of coke in the charged material by one facility.

<First half 1/2 stack>
As is clear from FIGS. 8 to 11, when compared with each pattern of cutting out the raw material, the first half ½ layer is more uniformly charged with coke over the entire discharge than the other patterns. I can confirm. For this reason, the cutting of the raw material is particularly preferably the pattern of the first half ½ overlap shown in FIG.
By cutting out the raw material in the first half, it is uniformly mixed as a blast furnace operation. In addition, it is possible to charge a large amount partially from the furnace wall side to the center side by mixing and charging the raw material cut out in the first half ½ and the current plate 16 inclined to the plus side. Become.

  The raw material charging method for the bell-less blast furnace according to the present invention can control the change with time of the ratio of coke in the mixture of ore and coke during the coke mixing charging.

  DESCRIPTION OF SYMBOLS 1 ... Secondary raw material hopper, 2 ... Current plate, 3 ... Movable shaft, 10 ... Secondary raw material hopper, 11 ... Raw material charging part, 12 ... Tapered part, 13 ... Raw material discharge part, 14 ... Discharge port, 15 ... Gate, 16 ... Rectifying plate, 17 ... Movable shaft, 20 ... Loading belt conveyor, 21 ... Belt conveyor, 22 ... Sampling box.

Claims (4)

In addition to the main raw material hopper at the top of the furnace, in the raw material charging method of the bell-less blast furnace having the auxiliary raw material hopper,
The mixture of ore and coke is charged into the auxiliary raw material hopper,
The mixture is formed by laminating the coke on the ore when the ore and the coke are cut out on a charging belt conveyor,
The auxiliary raw material hopper is a flat plate and has one rectifying plate having a movable shaft,
The flow straightening plate is a first plate in which the flat plate faces the raw material charging direction from the charging belt conveyor, and the auxiliary raw material hopper is positioned in front of the raw material charging direction with respect to the straightening plate. It is installed so as to bisect into a region and a second region located on the back side in the raw material charging direction with respect to the current plate,
The portion of the rectifying plate above the movable shaft bisects the drop trajectory of the mixture while the mixture freely falls from the charging belt conveyor into the auxiliary raw material hopper. Determine the charging position of the coke in the auxiliary material hopper,
A portion of the rectifying plate below the movable shaft is above the discharge port of the auxiliary material hopper, and the first discharge flow path through which the charge charged in the first region passes and the first Forming a second discharge flow path through which the charge charged in the region 2 passes, and the charge from one of the first discharge flow path and the second discharge flow path. Is preferentially discharged,
A bellless blast furnace raw material charging method , wherein an angle of the rectifying plate is determined in advance so as to obtain a desired change with time in the ratio of the coke in the mixture discharged from the auxiliary raw material hopper. When laminating the coke on the ore on the charging belt conveyor,
The raw material charging method for a bell-less blast furnace according to claim 1, wherein the coke is stacked within 50% of the total stacking length on the charging belt conveyor. 4 batch charging performed in the order of Cc, C ₁ , O ₁ , O ₂ ,
In charging the O ₁ with the mixture,
The method of charging a bellless blast furnace according to claim 1 or 2, wherein the amount of coke discharged during the first 50% discharge time is increased with respect to the total discharge time from the auxiliary material hopper. 4 batch charging performed in the order of Cc, C ₁ , O ₁ , O ₂ ,
In charging the O ₁ with the mixture,
3. The bellless blast furnace raw material charging method according to claim 1, wherein the amount of coke discharged in the second half 50% discharge time is increased with respect to the total discharge time from the auxiliary raw material hopper.

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