JPS61157604A - Introducting method of raw material for blast furnace - Google Patents

Abstract

PURPOSE:To control surely the grain size distribution in the diameter direction of raw material in a discharging period by providing a hollow cylinder movable up and down in the inside of a furnace top banker and introducing the different raw materials into the bunker and the cylinder. CONSTITUTION:A hollow cylinder 14 is provided movably up and down in the inside of a lower stage furnace top bunker 11 between two-stage furnace top bunkers. A fine granular raw material 20 discharged in an initial period is introduced into the hollow cylinder 14 and a middle granular raw material 21 is introduced into the bunker 11. Then a coarse raw material 22 is accumulated on the middle granular raw material 21. The fine granular raw material 20 in the hollow cylinder 14 is preferentially discharged by opening a gate valve 9. The middle granular raw material 21 of the bottom of the bunker 11 is discharged by elevating the hollow cylinder 14. The coarse granular raw material accumulated in the upper part of the bunker 11 is discharged by elevating more the hollow cylinder 14. The same operation is performed for a parallel type furnace top bunker. The change of the discharged raw material with time can be efficiently controlled in case of utilizing this method.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for charging raw materials into a blast furnace, and in particular, in a method for charging raw materials using a so-called bellless type charging device consisting of a top bunker and a rotating chute, The present invention relates to a raw material charging method for controlling changes over time in the particle size of charged raw materials charged into a furnace from a bunker via a rotating chute.

Prior art and its problems In operating a blast furnace, it is necessary to appropriately control the gas flow distribution in the radial direction within the furnace to stably reduce and dissolve the ore within the furnace. As a method of controlling the gas flow distribution in the radial direction inside the furnace,
A method based on controlling the burden distribution at the top of the furnace is often used. This charge distribution control is performed by controlling the radial weight ratio distribution of ore and coke, the radial particle size distribution, the radial porosity distribution, etc. .

For example, in the case of a conventional bellless charging device in which top bunkers are installed in parallel, the raw material is transferred to the belt conveyor (1), the upper gate valve (2), and the upper seal valve (3), as shown in Figure 5. Once the charge in the blast furnace is unloaded and reaches a predetermined stock level (5) to be replenished, the lower gate valve for adjusting the charge flow rate is (6) and the lower seal valve (7) are opened, the raw material in the top bunker (4) is rotated and dropped onto the neat (8), and the tilting angle and rotation speed of the rotating chute are adjusted to are continuously charged into the furnace through the rotating chute (8).

However, in conventional bellless charging, as is clear from the example of the classification of raw materials that occurs when charging raw materials into the top bunker shown in Figure 6, the raw materials are placed on the slope of the raw materials formed in the bunker (4). Classification occurs, with fine grains depositing at the charging position and coarse grains depositing on the bunker wall. In the example shown in FIG. 6, since the grain size distribution of the sintered ore is large, the grain size segregation in the radial direction within the bunker is large. Furthermore, as will be explained in detail later, the discharge behavior of the charge in the top bunker is not uniform, and therefore the grain size of the charge constituted by the top bunker changes significantly over time.

For this reason, the conventional bellless charging method in which the distribution of the charge is controlled by simply changing the tilting angle, rotation speed, etc. of the rotating chute has been insufficient in controlling the distribution of the charge.

Therefore, in recent years, a method has been proposed called ``grain size-based charging'' in which raw materials with different particle sizes are divided and charged into the furnace to finely adjust the radial distribution of the burden. 55-16
203). However, the conventional charging technology according to particle size has the following problems.

■ Since the raw materials are charged in parts, the charging time per charge becomes longer, and there is a possibility that it will not be possible to keep up with the increase in the production volume of the blast furnace. Further, by doubling the number of times of pressure equalization and evacuation, the amount of gas (N2 gas, etc.) required for it is doubled.

■ In order to obtain raw materials with different particle sizes, separate classification operations such as mechanical classification using a sieve or air flow classification using compressed air during transportation are required.

Purpose of the Invention This invention was made to solve the above-mentioned conventional problems. The purpose of this study is to propose a raw material charging method that can accurately control the radial particle size distribution by utilizing the discharge characteristics of .

Structure of the Invention The method of charging raw materials for a blast furnace according to the present invention is a method for charging raw materials into a furnace using a bellless type furnace top device in which top bunkers are vertically installed in two stages. A hollow cylinder that can be moved up and down is installed, and raw materials with different particle sizes are charged into this hollow cylinder and a lower furnace top bunker.The raw materials in the hollow cylinder are discharged by a gate valve, and the raw materials in the lower bunker are Pelless charging wL features a hollow cylinder that moves up and down to discharge, and has top bunkers installed in parallel.
In the case of the method of charging the raw material from the above, a hollow cylinder similar to the above is installed in each furnace top bunker, and the raw materials in each furnace top bunker are discharged by moving the respective hollow cylinders up and down. The raw material inside the furnace is discharged through the gate valve of each furnace top bunker.

The method of this invention will be explained in detail below.

FIG. 7 is a diagram showing an example of the change over time in the particle size of raw material discharged from the top bunker of a bellless blast furnace.

That is, in the case of a bellless type charging device, fine particles of both sintered ore and coke are charged into the furnace at the beginning of discharge, and coarse particles are charged into the furnace at the end of discharge. This tendency is more pronounced for sintered ore.

Moreover, FIG. 8 is a double diagram of the order of discharging raw materials from the furnace top bunker. That is, the raw material in the bunker is discharged in the following order: (a) a flowing region above the discharge gate valve (6), and (b) a stationary region (iv) on the bunker wall. In the figure, θA is the angle formed with the vertical direction of the final flow zone ■, and θB is the angle at which the raw material in the static zone ■ flows into the flow zone.For example, the bunker diameter is 6.0 m, the gate valve diameter is 75 Q jll, and the bunker reduction part. Angle θ is 6
In the case of 0°, the results are as shown in Table 1. Note that the raw material discharge behavior described above is 7ransacti6nsOf Iron
and 5teel In8titude Of Ja
It can be estimated using the simulation model described in Pan" Vol. 24, 1984, p. 799.

Table 1 On the other hand, if the charging position of the raw material into the furnace top bunker is on the vertical line of the discharge gate valve, due to the slope classification effect, fine particles will be in the flow zone and coarse particles will be in the stationary zone. accumulate. Therefore, when raw materials are discharged from the bunker, the fine particles in the flow zone are discharged at the beginning of the discharge, and the coarse particles in the stationary zone (1) are discharged at the end of the discharge.

This invention was made based on the above knowledge, and includes installing a hollow cylinder in the center of the furnace top bunker, forming the above-mentioned flow region within the hollow cylinder, and forming a stationary region (2) around it. This method controls the particle size of the raw material charged into the hollow cylinder when charging the raw material into the bunker, and also moves the hollow cylinder up and down to charge the raw material in the bunker into the furnace. That is, the present invention is a method for controlling the particle size of the raw material charged into the furnace by first discharging the raw material in the hollow cylinder when discharging the raw material in the bunker.

As shown in Figure 1, in the case of a bellless blast furnace in which the top bunker is installed in two stages in the height direction coaxially with the blast furnace axis, a rope 0 is attached to the pulley α installed on the ceiling of the lower bunker (1).
3), the hollow cylinder (14) is suspended by this rope, and the hollow cylinder (14) is suspended by operating the rope (14).
1 is moved up and down, and a rope (
16i is used to open and close the upper lid αη of the hollow cylinder. Note that one end of the upper lid 07) is fixed to a hinge-structured mounting jig α~ provided at the upper open end of the cylinder.

The vertical movement of the hollow cylinder α4) and the opening and closing of the upper lid θη are performed by driving a wire drum (not shown) provided outside the furnace with a motor.

(10) is the upper furnace top bunker, and α9) is the gate valve.

The diameter of the hollow cylinder is not particularly limited, but may be approximately the same as the diameter of the gate valve α.

In a vertical two-stage furnace top bunker, if a hollow cylinder with a lid that can be moved up and down is installed in the lower bunker by the above method,
For example, when discharging fine grains at the beginning of discharge, medium grains during the middle stage of discharge, and coarse grains at the end of discharge, the raw material accumulation in the bunker is during the raw material charging stage to the lower bunker and the raw material discharge stage from the bunker. The situation is schematically shown in Figure 2.

That is, in the charging period, the fine raw material discharged from the upper bunker is initially intensively charged into the hollow cylindrical ring. At this time, the gate valve (IF4) is of course closed. When a predetermined amount of fine grain raw material (3) is deposited in the hollow cylinder (I4), the upper lid tJ7 of the hollow cylinder is closed, and the medium grain raw material is discharged from the upper bunker. Gradual raw material is charged into the river and is gradually deposited on the outside of the bunker (hollow cylinder α4) (middle stage).At the end of the charging period, the coarse raw material discharged from the upper bunker is deposited in the hollow cylinder (α4). 14) Deposit to near the top surface.

Next, during the raw material discharge period, the gate valve (19) is opened to preferentially discharge the fine raw material (3) inside the hollow cylinder Q4).

In the middle stage when the discharge of fine raw materials is finished, the hollow cylinder is 0
41 is slightly raised to discharge the medium grain raw material (21) deposited on the river bottom.At the end of the discharge period, the hollow cylinder α4 is further raised to the outside of the raw material accumulation layer, and the upper part of the bunker is discharged. The coarse grain raw material (3) that had accumulated in the tank is discharged.

In addition, if you want to discharge coarse particles at the beginning of discharge, medium particles at the middle of discharge, and fine particles at the end of discharge using the same method as above, Figure 3 shows the raw material accumulation situation at the charging stage and discharge stage. As shown schematically, at the beginning of the charging period, the gate valve α instant,
Then, close the upper lid aη and deposit a predetermined amount of fine grain raw material (B) in the bunker outside the hollow cylinder H (at the bottom of the river.Subsequently, in the middle stage, medium grain raw material Q1) is charged onto the fine grain raw material layer. Then, it is deposited up to the vicinity of the upper lid αη of the hollow cylinder Q41. Then, at the final stage, the upper lid (17) of the hollow cylinder (I4I) is opened and the coarse raw material (5) discharged last from the upper bunker is charged into the cylinder.

Next, during the raw material discharge period, the gate valve (opens once) to preferentially discharge the coarse raw material (b) inside the hollow cylinder.In the middle stage when the discharge of the coarse raw material is completed, the The cylinder H is raised to take it out of the raw material accumulation layer inside the bunker, and the medium-grained raw material is deposited at the top of the bunker using the raw material discharge characteristics (funnel flow) from the bunker (21).
be discharged first. At the final stage, the fine raw material 1120) deposited at the bottom of the bunker is discharged.

In addition, if the hollow cylinder α4) is not taken out of the raw material layer in the bunker in the middle of the discharge period, the fine grain raw material at the bottom of the bunker will be discharged first, and the raw material particle size at the end of the discharge period will be medium. The effect of the period cannot be obtained.

On the other hand, in so-called parallel type bunkers in which furnace top bunkers are installed in parallel at the same height position, a hollow cylinder of the type shown in FIG. 1 is installed in each bunker.

However, in the case of a parallel bunker, unlike in the case of a vertical two-stage bunker, the particle size of the raw material charged into the bunker is constant, and the particle size of the charge charged into the bunker does not change over time. do not have. Therefore, if it is desired to discharge fine-grained raw materials at the beginning of discharge and coarse-grained raw materials at the end of discharge, this can be achieved satisfactorily without using the method of the present invention. However, on the contrary, it is not possible to suppress the change in particle size over time. The method of this invention makes it possible to suppress the above-mentioned change in particle size over time, and the method will be explained based on FIG. 4.

Figure 4 schematically shows the stacking situation of raw materials during the charging and discharging stages in a parallel bunker.At the beginning of the charging stage, the gate valve (19) is closed and the hollow cylinder (+4) is When a predetermined amount of raw material is charged into the hollow cylinder (141), the upper lid θη of the cylinder is closed, and the raw material is charged to the outside of the hollow cylinder inside the bunker 01. Charge raw materials (middle stage of charging).

At the end of the charging period, the raw material is deposited up to the vicinity of the upper surface of the hollow cylinder 04). In the middle and final stages of the charging period, the raw material to be charged is classified in the bunker by slope classification, with coarse particles on the outside and fine particles on the inside.

Next, in the discharge period, the gate valve α is initially opened to discharge the raw material inside the hollow cylinder (+4). Subsequently, in the middle and final stages of discharge, the hollow cylinder 041 is slightly raised to sequentially discharge the raw materials accumulated in the bunker outside the hollow cylinder from the bottom. At this time, the raw materials that have been classified in the bunker are discharged at the same time.

Effects of the Invention As explained above, according to the method of the present invention, in a two-stage bunker with an upper and lower bunker, by installing one hollow cylinder in the lower bunker, the material charged into the central part of the bunker, that is, the flow area, can be reduced. In addition to being able to control the particle size, it is also possible to control the time during which the raw material in the flow zone is discharged when charging the raw material from the bunker into the furnace, and in the case of parallel bunkers, classification occurs within the bunker. By discharging the raw materials at the same time, the average particle size of the discharged raw materials can be kept almost constant, so whether the bunker is a two-stage bunker or a parallel bunker, the raw material discharged from the bunker into the furnace is It is possible to control changes over time more accurately, and this has an extremely large effect on the operation of the blast furnace.

[Brief explanation of the drawing]

@Figure 1 is a schematic diagram showing an example of the configuration of an apparatus for carrying out the method of the present invention, Figures 2 to 4 are explanatory diagrams of the raw material charging method of the present invention using the same apparatus as above, and Figure 5 is a diagram showing the furnace top bunker. Schematic diagram showing a conventional bellless charging device arranged in parallel, No. 6
The figure shows an example of the classification situation of raw materials that occurs when charging raw materials into a conventional bell-less furnace top bunker, and Figure 7 shows an example of the change over time in the particle size of raw materials discharged from a conventional bell-less furnace top bunker. FIG. 8 is a schematic diagram showing the order in which raw materials are discharged from the furnace top bunker. 11... Lower bunker, 14-... Hollow cylinder, 19.
...Gate valve, 20...Fine-grained raw material, 21...Medium-grained raw material, 22...Coarse-grained raw material, 31...Parallel type furnace top bunker, 33... Raw material. Applicant: Sumitomo Metal Industries, Ltd. Figure 1 Figure 2 Figure 3 Figure 4 Figure 7 Door Figure 5 Hundred Figure 8

Claims (1)

[Scope of Claims] 1. A method for charging materials into a blast furnace using a blast furnace top charging device in which a top bunker is installed in two stages in the height direction coaxially with the blast furnace axis, and a rotating chute is provided in the furnace. A hollow cylinder that can move up and down is installed in the furnace top bunker, and raw materials with different particle sizes are charged into this hollow cylinder and the lower furnace top bunker, and the raw materials in the hollow cylinder are discharged by a gate valve and transferred to the lower furnace top bunker. A method for charging raw materials into a blast furnace, characterized in that raw materials in a bunker are discharged by moving the hollow cylinder up and down. 2. In a blast furnace raw material charging method using a blast furnace top charging device in which top bunkers are installed in parallel at the same height and a rotating chute is provided inside the furnace, a hollow cylinder that can be moved up and down is installed in each top bunker. is installed, raw materials with different particle sizes are charged into the hollow cylinder and the bunker, and the raw materials inside the hollow cylinder are discharged with a gate valve, and the raw materials inside the bunker are discharged by moving the hollow cylinder up and down. Characteristic blast furnace raw material charging method.