JPS61272304A - Method for distributing raw material to be charged - Google Patents

Abstract

PURPOSE:To uniformly distribute the raw material to be charged into a blast furnace and to stabilize the operation of the furnace by distributing and charging the raw material into a raw material storage hopper through a variable speed gyratory chute provided at the lower part of the uppermost part of a charging belt conveyor. CONSTITUTION:A gyratory chute 2 is arranged below a head pulley 1 at the uppermost part of a charging belt conveyor and a raw material storage hopper 3 is provided below the chute in a raw material charging device for a blast furnace. The gyrating speed of the gyratory chute 2 and preferably its tilting angle alpha are respectively made variable. The raw material discharging pattern is forcibly changed by varying the gyrating speed of the gyrating chute 2 and, if necessary, the tilting angle alpha during the time of charging each batch of the raw material. Consequently, the deflective distribution of the raw material accumulated in the hopper 3 is prevented and the charge of the raw material into the blast furnace is made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for uniformly distributing the charge at the top of a blast furnace.

(Prior art and its problems) As an example of the prior art, Japanese Utility Model Publication No. 59-5725 (
(hereinafter referred to as this example) is disclosed in FIG.

In this example, raw materials conveyed from the ground by a charging conveyor 4 are distributed into a storage hopper 3 by a rotating shoe 2. Further, the rotating chute 2 may be installed in a pressure equalizing hopper, but in any case, the aim is to charge the raw material in as uniform a state as possible before charging it into the furnace.

However, the charging conveyor in recent large blast furnaces is very long, reaching 300MK, and it is difficult to avoid separation of fine grains from the bottom and large lumps from the top due to vibrations during conveyance. This tendency becomes more and more pronounced for the raw material discharged from pulley 1, with large lumps falling far away and fine particles falling near the head pulley IJ l.This tendency has been pointed out in the past. However, in this state, the raw material that has fallen onto the rotating chute 2 slides down the rotating chute 2 and is distributed into the storage hopper 3.The two representative positions of the rotating chute 20 are shown by solid lines and dotted lines, The operation of the granule is as follows.

(11 The vertical relationship between large lumps and fine particles is different, and storage hopper 3
The width of the fall changes.

(2) The flying distance (BF
distance from φ) are different. That is, the distribution width and the radial position (top of the mountain) differ depending on the circumferential position within the storage hopper 3.

Furthermore, in this example, the raw material falling from the helad pulley 1 is concentrated at the center of the rotating chute 2, but due to differences in sintering, raw ore, coke quality and particle size, or changes in the charging amount, the raw material may be concentrated in the direction of the charging conveyor. It is common for the distribution to deviate, and in this case, the distributability is further affected. In other words, the difference in downhill time relative to the total amount causes a quantitative change when looking at the distribution on the circumference.

The above various segregations (non-uniform distribution of charged raw materials) are carried into the furnace as they are, causing non-uniformity in the gas flow in the furnace and even in the reactions within the furnace, resulting in a reduction in the efficiency of blast furnace operation and different iron extraction. Even the difference in the composition of the pig iron that comes out of the mouth is connected.

In this example, the time required for the raw material discharged from the head pulley 1 to reach the outlet from the entrance of the rotating chute 2 is Δti.
shall be. Now, assuming that Δti is constant regardless of the exit direction VC of the rotating chute 2, each point (
1 to 12), it is distributed uniformly in the circumferential direction, but even in this case, as in the left and right falling trajectory example in Fig. 4,
The radial non-uniformity at each point is caused by a change in the position of the pivoting chute 2 in the direction of the exit. Actually turning chute 2
ΔtL differs at each position of the rotating chute 2, taking into consideration the influence of the shape of the chute, the relative positional relationship with the helad pulley 1, quantitative and qualitative changes in the charged raw material, etc. An example of this state is shown on the outer circumferential circle in FIG. In this state, non-uniformity on the circumference is added, and the distribution shape 1g of the raw material is further deteriorated.

In any case, the raw material falling position in the first and second rounds is the same, and as the number of revolutions increases, this uneven distribution accumulates.
The tendency for non-uniformity becomes remarkable. In other words, in the conventional equipment, although the distribution of large lumps and fine particles of the raw material is improved to some extent by installing the rotating chute 2 compared to not installing the rotating chute 2, it is not enough from the viewpoint of the reaction inside the furnace or the operation. It is clear that it was not.

OBJECTS OF THE INVENTION It is an object of the present invention to solve the problems of the prior art described above and to provide a distribution method that makes it possible to uniformly distribute the charging material in the furnace.

(Structure of the Invention) That is, according to the present invention, a charging apparatus for a blast furnace is provided with a rotating chute at the bottom of the top of a charging belt conveyor and a raw material storage hopper below it. A method for distributing charged raw materials, characterized in that the rotating speed of the rotating chute is made variable within each batch charging time,
is obtained.

Further, according to the present invention, both the turning speed and the tilting angle of the above-mentioned turning chute can be made variable.

FIG. 1 is a longitudinal view of one embodiment of the present invention.

The most important point of the present invention is to change the falling point of the raw material every rotation, and for this purpose, two rotating chutes are required for one batch (one pile of loaded raw material on the charging conveyor). The idea is to rotate the robot continuously and to make the rotation speed variable. That is, the material discharge pattern from the rotating chute is forcibly changed within each batch charging time of the charged material.

During the Δti time during which the raw material passes through the rotating chute 2, the rotating chute 2 rotates by Δθi. here,
When the rotating speed of the rotating chute 2 is changed, the rotation angle at that time becomes Δ0'i, and the raw material is discharged to a position different from the position where it was previously discharged.

There are two ways to change the speed: one is to change the speed every turn or every few turns, and the other is to change the speed continuously. Both of these methods satisfy the gist of the present invention, but continuous changes are simpler. be. Furthermore, whether this variation is a deceleration method or an increase speed method does not detract from the gist of the present invention, the storage hopper 3 is generally in the form of an internal hopper with a small diameter at the bottom and a large diameter at the top. Therefore, the direction of speed increase is more desirable.

This is because a horizontal component force due to inertia is added to the raw material discharged from the rotating chute 2 due to the speed increase, resulting in the raw material falling position being shifted further toward the outer circumference, and moving from the lower end of the storage hopper 3 toward the upper end. As the raw material is deposited, the top of the pile rises along the wall of the hopper 3, and when the deposition is completed, it almost forms a mold. This state is shown in FIG. The right figure is the conventional type, and the left figure is the inventive type. First, fall trajectory A1 in the figure on the right.
In this case, the charged material falls onto the deposited material, resulting in a so-called self-lining process, which avoids wear on the side walls, but
The shape of the final deposited raw material pile becomes M-shaped, and the effective capacity of the hopper 3 becomes small. In the case of a hopper, the effective capacity is V-shaped and larger, but until the deposited raw material reaches zero point, that is, most of the raw material hits the same place on the hopper wall, and the wear in this area is severe and practical. Moreover, the negative effect of powdering the raw materials also occurs. At shows the case where the turning speed is slow, and A shows the case where the turning speed is fast, but the left diagram of the present invention is an example of a case where the turning speed is increased appropriately, and an ideal type with a large effective capacity and no wear can be obtained. It was shown that

In addition, the tilting angle α (the fourth It is also possible to change the tilting angle of the chute 2 to make the effective volume larger (see the figure) and increase the effective volume.

FIG. 2 shows an example of a change in the material falling point on a plane during speed increase according to the present invention when Δti is constant.

As is clear from the figure, the falling position changes from moment to moment, and naturally it was found that the falling position did not fall at the same location at the same entrance and the second floor, and even after that.

The rotation speed and number of rotations are determined by the batch amount and its charging time, which vary depending on the size of the blast furnace, charging conditions, etc., and the quality of the raw material.

Note that when changing the rotation speed, the charging amount per unit area will naturally change over time, but this does not affect the gist of the present invention, which is not to repeatedly charge the same distribution at the same point. Various electrical and hydraulic methods can be considered for this variable operation.

(Effects of the Invention) By adopting the above configuration, the present invention can obtain the following effects.

(1) The directionality of the raw material charged from the charging belt conveyor is corrected, and uniform distribution of the raw material with respect to the blast furnace axis can be achieved.

This leads to uniformity of the raw material input into the furnace, and it is possible to improve the operability of the blast furnace.In other words, it helps to make effective use of reducing gas by uniformizing the gas flow, improves economic efficiency by reducing fuel costs, and improves the operability of the blast furnace. It becomes possible to homogenize the composition of molten iron taken out from the tap hole.

(2) If the rotating chute is operated at an increased speed, the speed at which the raw material flies out at the outlet of the rotating chute increases due to the increase in inertial force, the flying distance increases, and the material falling point can be moved in the radial direction. This prevents the charged raw material from directly hitting the storage hopper wall, which means that the raw material is not powdered and the wall is not abraded, and the shape of the raw material pile becomes closer to a v-shape, which increases the storage hopper height. In other words, by reducing the height of the blast furnace,
The economic effects are also significant in terms of equipment costs and operating costs.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view comparing an embodiment of the present invention with a conventional example. Figure 2 is a cross-sectional view showing the non-uniform distribution of falling raw materials on the outer periphery of the hopper, Figure 3 is a cross-sectional view showing the uniform distribution of falling raw materials according to the present invention, and Figure 4 is the horizontal cross-sectional view of the conventional example. FIG. 3 is a vertical cross-sectional view showing an example of a trajectory. In the figure, 1-111 Rad pulley 2-111 Swinging chute 3-111 Storage hopper 4-111 Carrying conveyor

Claims (2)

[Claims] (1) In a blast furnace raw material charging device that has a rotating chute at the bottom of the top of the charging belt conveyor and a raw material storage hopper below, the rotating chute is A method for distributing charged raw materials characterized by making the rotation speed variable. (2) In a blast furnace raw material charging device that has a rotating chute at the bottom of the top of the charging belt conveyor and a raw material storage hopper underneath, the rotating chute is A method for distributing charged raw materials, characterized in that the rotation speed and the tilting angle thereof are made variable.