JPH05302107A - Method for activating furnace core in blast furnace - Google Patents

Abstract

PURPOSE:To reduce a furnace core part, to prevent the generation of an inactive zone and to activate the furnace core in a blast furnace by projecting the tip parts of about half the number of tuyeres among the tuyeres for blowing hot blast in the blast furnace toward the furnace core side in deeper than that of the remaining tuyeres by a specific length. CONSTITUTION:The tip parts of 30-70% pieces of the tuyeres 2a among the plural tuyeres for blowing hot blast arranged in the circumferential direction of the blast furnace 1 are protruded toward the furnace core 4 side in deeper than that of the remaining tuyeres 2b arranged at the ordinary position by 50-200mm. By the protruded tuyeres 2a, plural coke circulating ranges 3a are formed in a circular direction at the position near the furnace center than that of an ordinary method and the furnace core 4 can be made to be smaller than that of the ordinary method. Further, the inactive zones going to be generated above the tuyeres 2a are prevented from generation by the coke circulating ranges 3b at the ordinary position formed with the remaining tuyeres 2b. Thus, the inactive zone in the furnace core part in the blast furnace is activated, and the productivity of molten iron in the blast furnace is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for activating a blast furnace core that activates an inactive zone of the blast furnace core to improve the productivity of hot metal.

[0002]

2. Description of the Related Art Hot air used for coke combustion in a blast furnace is, as shown in the longitudinal sectional view of the blast furnace in FIG. 2, equidistantly along the circumference of the lower part of the blast furnace 21 and in the core direction. The air is blown from a plurality of tuyere 22 provided so that hot air can be blown toward it. A coke turning area 23 called a raceway is formed in front of the tuyere 22. In the coke swirl region 23, the coke is burned and gas is generated.

The generated gas rises in the blast furnace 21 and reacts with the iron ore during the ascent to reduce the iron content of the iron ore. By such a reaction, in the blast furnace 21 above the coke swirl region 23, a dripping zone 24 in which pig iron has started dripping from iron ore, a cohesive zone 25 in which iron is in a semi-molten state, a reduction reaction A reduction zone 26 is formed in which Further, in the blast furnace 21 below the coke swirl region 23, a slag 27 formed after the iron content is reduced from the iron ore is accumulated, and further a layer in which the pig iron 28 is accumulated is formed under the slag 27, and the pig iron 28 is intermittently formed. It is tapped from the tap hole 29.

By the way, since the hot air blown from the tuyere 22 does not reach from the coke swirl region 23 to the furnace core as shown in FIGS. 2 and 3 which is an AA arrow view of FIG. Area where reaction is not promoted (called furnace core) 30
Occurs. This core 30 portion is literally a dead space of the blast furnace, and remarkably impairs the productivity of the blast furnace. Therefore, it is desirable to make the core 30 as small as possible.

A technique for reducing the above-mentioned core 30
That is, as a conventional technique for improving air permeability, there is a method described in JP-A-63-277706.
This method is to detect the balance and unbalance of the air permeability in the circumferential direction, and control the air permeability in front of each tuyere based on the detection result to balance the air permeability in the circumferential direction. ..

[0006]

However, although the above-described technique for improving the air permeability in the blast furnace of the related art leads to the improvement of the air permeability of the coke swirl region 23, it does not lead to the reduction of the core. There was a point.

Further, in order to reduce the core of the furnace, a method of increasing the protruding length of the tuyere into the furnace may be considered. However, if the protruding length of the tuyere is lengthened, an inactive zone is formed on the tuyere. Appeared,
There is a problem that the tuyere slips off or melts due to the fall of the adhered matter attached to the tuyere.

[0008] Further, a method of increasing the level of the amount of heat input into the furnace to reduce the core can be considered, but it takes about one month until the core disappears, so even with this method a large reduction in production is avoided. There was a problem that I could not do it.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and a blast furnace in which the furnace core can be limited to a narrow range and an inert zone is not generated in the upper tuyeres. It is intended to provide a method for activating a core.

[0010]

A method for activating a blast furnace core according to the present invention comprises 30 to 7 of tuyere for blowing hot air in a blast furnace.
0% of tuyere is 50 ~ 200m more than remaining tuyere
The tip of m is projected to the furnace core side.

[0011]

In the method for activating a blast furnace core according to the present invention, 30 to 70% of the hot air blowing tuyeres of the blast furnace are provided with 30 to 70% of the tuyere, and the tip is located 50 to 200 mm from the remaining tuyere toward the core side. The reason why it is made to protrude is as follows. That is, it has been known that if the protruding length of the tuyere into the blast furnace is increased, the core decreases but the inactive zone above the tuyere increases. We examined whether a part of the tuft should be overhanging or how long it should be projected to limit the length of the inactive zone above the tuyere.

As a result, the number of the tuyere protruding from the conventional position is 30 to 70% of the total, and the protruding length is 50 to 200 mm as compared with the conventional case. The reasons for the limitation are as follows. That is, if the number of protrusions is less than 30%, there is no effect of reducing the furnace core, and if it exceeds 70%, an inactive zone at the upper part of the tuyere occurs. Further, if the protruding length is less than 50 mm, there is no effect of reducing the furnace core, and if it exceeds 200 mm, the tuyere is melted and damaged.

[0013]

EXAMPLE A method for activating a blast furnace core according to an example of the present invention will be described with reference to FIG. 1 showing a cross section of the tuyere of the blast furnace. A method for activating a blast furnace core according to an embodiment of the present invention is such that half of the tuyere 2a arranged in the circumferential direction of the blast furnace 1 are
50-200mm more than the tuyere 2b placed in the normal position
It sticks out toward the center of the furnace. By doing so, a plurality of coke swirl regions 3a are formed in the circumferential direction at a position closer to the center of the furnace than in the conventional case, so that the furnace core 4 can be made smaller than in the conventional case.

Further, the inactive zone which is about to appear on the tuyere 2a does not appear due to the coke swirling region 3b formed by the remaining tuyere 2b at the conventional position. If the number of protruding tuyere is less than 30% of the total, there is no effect of reducing the core, and if it exceeds 70%, an inactive zone occurs at the upper part of the tuyere, so it is set to 30 to 70% of the whole There is a need. If the protruding length is less than 50 mm,
The furnace core does not decrease, and if it exceeds 200 mm, the tuyere will be melted and damaged. Therefore, it must be in the range of 50 to 200 mm.

Since the method for activating the blast furnace core according to one embodiment of the present invention is performed as described above, it is possible to reduce the core without causing an inactive zone to appear in the upper part of the tuyere. The productivity of can be improved.

[0016]

According to the present invention, the core of the blast furnace can be reduced.

[Brief description of drawings]

FIG. 1 is a transverse cross-sectional view of a tuyere portion of a blast furnace for explaining a method for activating a blast furnace core according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a blast furnace.

FIG. 3 is a view on arrow AA of FIG.

[Explanation of symbols]

 1 blast furnace 2a tuyere 2a tuyere 3a coke swirl area 3b coke swirl area 4 core

Claims (1)

[Claims] 1. 30 to 70 of tuyere for blowing hot air in a blast furnace
% Tuyeres 50-200 mm more than the remaining tuyere
A method for activating a blast furnace core, which comprises projecting a tip toward the core side.