JP4139578B2 - Raw material charging method to blast furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a raw material charging method to a blast furnace, and in detail, using a raw material hopper that becomes a funnel flow installed at the top of the blast furnace, two or more kinds of raw materials such as iron ore, sintered ore, and pellets Is a raw material charging method to a blast furnace in which specific brand raw materials having a specific blending ratio are efficiently discharged from the raw material hopper into the blast furnace at a specific time and charged. characteristics of the coke which is charged into the blast furnace in correspondence with the (radial shape, etc.) to a method of charging raw materials.
[0002]
[Prior art]
The raw materials used in the blast furnace include iron ore, sintered ore, pellets, and other auxiliary materials such as limestone. These are individually and further classified according to the particle size, etc., and charged into each raw material hopper. Stored. When charging raw materials classified in this way into the blast furnace, each raw material is fed from the raw material hopper to the belt in the required blending amount in order to stabilize the operating conditions of the blast furnace and the quality of the pig iron produced. The blast furnace operation is carried out while charging the coke and the raw material cut out from the collect hopper alternately into the blast furnace from the top of the furnace while precharging the blast furnace in a batch for each batch of blast furnace cut out on the conveyor. Is called.
[0003]
By the way, in the blast furnace operation, to stabilize the operating conditions of the blast furnace, etc., even during operation, finely adjusted raw material charging, for example, specified brand raw materials with different blending ratios such as sintered ore and pellets at the specified time It is necessary to do things such as charging inside and adjusting the flow of gas in the furnace. In such a case, in the above raw material charging method to the blast furnace, iron ore, sintered ore, pellets, etc. The blending ratio is determined when it is cut out from the raw material hopper, and is cut out from the collective hopper and installed at the top of the furnace like a belt conveyor and bell-less type blast furnace, or a fixed hopper or bell type blast furnace for feeding raw materials. At the time of charging into the furnace through the bell banker, the degree of mixing of iron ore, sintered ore, pellets, etc. is increased. For this reason, for example, pellets and briquettes are placed at desired positions in the furnace. Ratio of formulation can not be performed with good timing to a specific time that such charged a certain brand material, such as relatively small.
[0004]
Therefore, the present inventors repeated research and research to improve the above-mentioned problems, and first, using a raw material hopper such as a fixed hopper for raw material input installed at the top of the furnace, iron ore, sintered ore, When charging two or more kinds of raw materials such as pellets into the furnace, the raw materials for the blast furnace that efficiently discharge and charge the specific brand raw materials with a specific mixing ratio from the raw material hopper into the blast furnace at a specific time. A charging method was developed and provided (see Japanese Patent Application No. 2000-3701).
[0005]
On the other hand, pellets and sintered ore with very different properties are mainly used as the raw material (raw material) charged to the blast furnace. The conventional distribution control method for the raw material distribution to the blast furnace distributes to the brands of these raw materials. Therefore, it is difficult to control and charge it into the blast furnace furnace, so it is controlled by uniformly mixing it with other ores in advance on the belt or in the raw material deposition hopper and charging it into the blast furnace furnace.
[0007]
[Problems to be solved by the invention]
The present invention has been made based on the above-mentioned actual situation, and the purpose thereof is a blast furnace capable of charging specific brand raw materials having different brands and repose angles with a concentration distribution in the radial direction in the blast furnace. The raw material charging method is provided.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the raw material charging method to the blast furnace according to the present invention (Claim 1) swirls the raw material containing pellets from the raw material hopper to be a funnel flow installed at the top of the bellless blast furnace. upon sequentially charged into the center portion from the outer peripheral portion via a chute in the furnace, with the furnace radial deposition geometry of the furnace top of the coke to be charged into previously M-type pile geometry, of the material hopper After charging the raw material into the raw material hopper so that the pellets are loaded in the middle of the straight body part, the raw material is cut out from the raw material hopper so that the pellets in the raw material have a dimensionless radius 0.8 in the furnace. The above-mentioned part is charged so that the pellet concentration is higher than the blending ratio of the pellets in the raw material .
Moreover, the raw material charging method to the blast furnace according to the present invention (Claim 2) is that the raw material containing pellets is fed into the furnace through a turning chute from the raw material hopper which becomes a funnel flow installed at the top of the bellless blast furnace. In order to sequentially charge from the outer peripheral portion to the central portion, the deposition shape of the coke to be charged in the furnace radial direction at the top of the furnace is changed to a V-shaped deposition shape, and the intermediate portion of the raw material hopper is placed in the middle of the straight body portion. After the raw material is loaded into the raw material hopper so that the pellets are loaded, the raw material is cut out from the raw material hopper so that the pellet in the raw material has a dimensionless radius of 0.1 in the furnace. It is characterized by charging so that it may become a pellet density | concentration higher than the mixture ratio of this.
[0010]
By the way, the present inventors have proposed the following raw material charging method to a blast furnace in Japanese Patent Application No. 2000-3701. In other words, the proposed method of charging raw materials into a blast furnace uses two or more types of raw materials such as iron ore, sintered ore and pellets using a raw material hopper installed at the top of the blast furnace and having funnel flow discharge characteristics. When charging into the furnace, grasp the raw material loading height position and funnel flow characteristics in the raw material hopper in advance, and identify the specific brand from the relationship between the grasped raw material loading height position and funnel flow characteristics. In order to charge the raw material into the blast furnace at a specific time, the raw material is loaded at a specific brand raw material loading height position in the raw material hopper, and discharged from the raw material hopper into the blast furnace furnace.
[0011]
The material discharge in the above funnel flow is slightly different depending on the hopper shape and the physical properties (shape, specific gravity, etc.) of the particles, but the upper part of the discharge port immediately below the hopper is preferentially discharged, and the funnel shape is formed on the upper surface of the material. A (funnel-shaped) hole is opened, the upper surface of the raw material around the hole collapses inside, the hole expands, reaches the inner wall of the hopper, and then the raw material is discharged from the upper part to the lower part along the wall. FIG. 1 schematically shows the discharge order, and the discharge is performed in the order of reference numerals (1) to (5). In the figure, 1 is a raw material hopper, 2 is a hopper inclined wall, 3 is a hopper body, 4 is a raw material, and 5 is a raw material surface position in the hopper. Further, α is an inclination angle of the hopper wall, and is formed at an angle smaller than (the angle of repose of the raw material to be cut out / 2 + 45 degrees), whereby a funnel flow is obtained.
[0012]
Thus, since the raw material in the raw material hopper is discharged as shown in FIG. 1, by introducing the raw material so that the specific brand raw material comes to the position in the raw material hopper at the time when it is desired to discharge, We thought that it was possible to efficiently discharge and charge specific brand-name raw materials containing two or more kinds of raw materials such as ores and pellets from the raw material hopper into the blast furnace at a specific time.
[0013]
Therefore, this was confirmed by experiments. Experiments were performed using 75% sintered ore and 25% pellets with almost no difference in average particle size as raw materials, and a hopper having a hopper wall inclination angle α = 50 ° as a raw material hopper.
[0014]
In the experiment, as shown in FIG. 2, the sintered ore 7 was charged into the raw material hopper 6, and first, the experimental brand was first charged at the position A (in the middle of the straight body). At the same time as discharging, the mixing ratio of the discharged pellets with respect to the elapsed time of the cutting time was measured. In this manner, the experimental brands are sequentially placed at the position B (the lower part of the straight body part), the position C (on the straight body part boundary), the position D (cone part 3/4), and the position E (cone part 1/4). Was measured in the same manner. The result is shown in FIG. Note that the cut-out time on the horizontal axis in FIG. 3 is shown as dimensionless with the time until cut-out completion being 1.00.
[0015]
As is clear from FIG. 3, the mixing ratio of the pellets to be discharged changes depending on the loading (loading) height position of the experimental brand raw material in the raw material hopper. A lot of pellets are discharged around the time, and at the position A, the center of the cone part is discharged at the beginning and a hole is formed. After that, it is discharged in the shape of a mortar. Can be seen. This shows that the raw material is discharged in the flow of (1) to (5) shown in FIG.
[0016]
As a result of further investigation and research based on the funnel flow discharge characteristics in the raw material hopper as grasped as described above, the raw material is placed in the blast furnace by changing the specific brand raw material loading height position in the raw material hopper. When charging, it was found that the distribution of the specific brand raw material in the furnace radial direction changes depending on the shape of the coke previously charged in the furnace in the radial direction . That is, in the same manner as described above, an experimental brand (specific brand) raw material of 75% sintered ore and pellet 25% having almost no difference in average particle size is used as a raw material, and a hopper wall inclination angle α = 50 as a raw material hopper. When an experiment was conducted using a hopper having a temperature of °, the result shown in FIG. 4 was obtained.
[0017]
In the above experiment, experimental brands (specific brands) at positions A (in the middle of the straight barrel), B (bottom of the trunk), or D (cone 3/4) in FIG. While a certain pellet is charged, the shape of the coke layer charged in the furnace radial direction at the top of the coke layer is V-shaped at the time of charging (deposition shape having a uniform inclination from the furnace wall toward the furnace center). And M type (the shape of the deposit with a uniform slope toward the center of the furnace after having a peak near the furnace wall) was charged into the experimental blast furnace. And the mixing ratio of the pellet of the radial direction in a furnace at this time was measured. FIG. 4a shows the case of V-type loading, and FIG. 4b shows the case of M-type loading.
[0018]
From the above FIG. 4a, when the coke is V-type charging, a lot of specific brands are deposited on the furnace center side at the position A, and the deposition on the furnace center side is slightly reduced at the position B, and the amount of It can be seen that the deposition is slightly increased and is considerably averaged at the D position.
Also, from FIG. 4b above, when the coke is M-type charging, there is much on the furnace wall side at the position A, less deposition at the peak height position of the coke, and a slight decrease on the furnace wall side at the position B. It can be seen that it slightly increases at the peak height position of the coke and is considerably averaged at the position of D.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 5 is a schematic view of the top of a bell-less blast furnace to which the raw material charging method according to the present invention is applied. The top portion 9 of the bell-less blast furnace 8 includes a fixed raw material hopper 10, a coke hopper 11, and a swivel chute 12, and the raw material and coke are alternately cut out from the raw material hopper 10 and the coke hopper 11. Is charged into the furnace. At this time, since the charged raw material is generally charged into the furnace by the turning chute 12 while turning from the outer peripheral part to the central part, the raw material hopper 10 in the furnace radial direction (from the outer peripheral part to the central part) in the discharge order. Raw material distribution occurs. In FIG. 5 , the raw material hopper 10 and the coke hopper 11 are depicted as being divided into left and right, but the charging order of the raw material O and the coke C during operation into the furnace (for example, O ↓ O ↓) Depending on C ↓ and the like, coke may be charged into the raw material hopper 10 and raw material may be charged into the coke hopper 11 side.
[0023]
Using the bell-less blast furnace 8, the specific brand raw material is made to correspond to the shape of the coke charged in the furnace at the top of the furnace radial direction (1) in a dimensionless radius of 0.8, and (2) The execution point of each method of charging so that it may become a density | concentration higher than the mixing | blending ratio of the said specific brand raw material in a raw material in the site | part of a dimensionless radius 0.1 is demonstrated. In addition, the specific brand raw material at this time is a pellet, and the mixture ratio is 25%.
[0024]
The implementation point of the above-mentioned method (1) of charging the specific brand raw material in a portion having a dimensionless radius of 0.8 so as to have a concentration higher than the blending ratio of the specific brand raw material in the raw material is as follows. That is, from the result of FIG. 4 (particularly, FIG. 4b), the deposition shape in the furnace radial direction at the top of the coke initially charged is changed to the M-type deposition shape, while the middle portion of the straight body portion of the raw material hopper 10 (FIG. 2). The specific brand raw material is charged via a belt conveyer at the position A) of (A). As a result, the specific brand material is charged while being controlled at a charging position in the furnace near a dimensionless radius of 0.8. In addition, the implementation point of the method of charging the specific brand raw material (2) so as to have a concentration higher than the blending ratio of the specific brand raw material in the raw material at a dimensionless radius of 0.1 is as follows. . That is, the a from 4 (especially Fig. 4a) result in the same manner, while the furnace radial deposition geometry of the furnace top of the coke to be charged into previously V-deposition geometry, straight body portion of the raw material hopper 10 A specific brand raw material is charged in the middle (position A in FIG. 2) via a belt conveyor and cut out. As a result, the specific brand material is charged while being controlled at a charging position in the furnace near a dimensionless radius of 0.1.
[0025]
As described above, even for specific brand raw materials with the same blending ratio, the specific brand raw materials are discharged into funnel flow in accordance with the shape of the coke previously charged at the top of the furnace in the radial direction. By charging the raw material hopper 10 having the characteristics at the same raw material charging height position and charging it into the blast furnace furnace, the specific brand raw material can be charged while controlling the distribution of the brand name in the radial direction.
[0030]
【The invention's effect】
As described above, according to the raw material charging process of the blast furnace according to the present onset Ming, stocks and different specific brand raw materials of repose angle, the furnace radial direction (the furnace center of the furnace top of the coke was charged into previously It is possible to charge with a concentration distribution in the furnace radial direction in the blast furnace furnace in accordance with the deposition shape between the wall and the furnace wall.
[0031]
Further, according to the raw material charging method to the blast furnace according to the present invention (Claim 2), the specific brand raw materials having different brands and repose angles are made to correspond to the deposition angle of the previously charged coke at the top of the furnace. The deposition angle (layer thickness) can be adjusted for charging.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the discharge order of raw materials by funnel flow in a raw material hopper.
FIG. 2 is a schematic diagram showing a charging position of a specific brand raw material in a raw material hopper.
FIG. 3 is a graph showing a relationship between a charging position of a specific brand raw material in a raw material hopper and a mixing ratio of discharged pellets with respect to an elapsed time after cutting.
FIG. 4 is a graph showing the blending ratio of specific brand raw materials in the furnace radial direction when the loading height position of the specific brand raw materials (pellets) in the raw material hopper is changed and charged into the blast furnace, a is when the previously charged coke is a V-type charge, and b is when the previously charged coke is an M-type charge.

Claims (2)

From the raw material hopper, which becomes the funnel flow, installed at the top of the bellless blast furnace, when the raw materials containing pellets are sequentially charged into the furnace from the outer periphery to the center through the turning chute ,
The raw material hopper is loaded with the pellets placed in the middle of the straight body portion of the raw material hopper, while the shape of the coke initially charged in the furnace radial direction is changed to the M-type stacked shape. After charging, the raw material is cut out from the raw material hopper so that the pellet concentration in the raw material becomes a pellet concentration higher than the blending ratio of the pellet in the raw material at a portion having a dimensionless radius in the furnace of 0.8. A raw material charging method for a blast furnace, characterized in that it is charged into a blast furnace. From the raw material hopper, which becomes the funnel flow, installed at the top of the bellless blast furnace, when the raw materials containing pellets are sequentially charged into the furnace from the outer periphery to the center through the turning chute,
The raw material hopper is loaded with the pellets placed in the middle of the straight body portion of the raw material hopper, while the shape of the coke initially charged in the furnace radial direction at the top of the furnace is changed to a V-shaped deposition shape. After charging, by cutting out the raw material from the raw material hopper, the pellet is charged in a portion having a dimensionless radius of 0.1 in the furnace so that the pellet concentration is higher than the blending ratio of the pellet in the raw material. A raw material charging method into a blast furnace characterized by:

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