JPH0941008A - Blast furnace furnace structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate sudden change of a wall surface profile in a furnace body by arranging a stave for cooling a furnace shell on the wall surface at the inside of the furnace of the furnace shell and forming the inner wall of a blast furnace, in a furnace body structure of the blast furnace constructed with the furnace shell. SOLUTION: The stave for cooling the furnace shell 5 is arranged on the wall surface of the furnace shell 5 at the inside of the furnace and brick is not laid on the inner surface of the stave, but the inner surface of the stave is formed as the inner wall of the blast furnace. By this constitution, the wear of the stave is small and the operation variation of formation of a mixed layer of the furnace wall, the variation of gas pressure, slippage, etc., caused by the sudden change in the height direction of the furnace of the wall surface profile in the furnace body can be eliminated and the stable operation of the blast furnace can be kept.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blast furnace body structure that guarantees stable operation of a blast furnace.

[0002]

2. Description of the Related Art The inner wall surface profile of the shaft portion to the bosh portion of a blast furnace changes after burning, due to the falling of bricks, wear and erosion. In particular, if the cross-sectional area of the furnace body is suddenly expanded or reduced due to brick fallout or erosion, or if projections are exposed inside the furnace and the profile of the wall surface inside the furnace changes significantly, the mixed layer near the wall surface inside the furnace Are formed, and the operation becomes unstable due to changes in the gas flow around the area, slippage, and irregular loading of the charge. In this way, when the furnace wall surface profile changes significantly, it is necessary to repair the furnace wall surface profile. For the shaft and furnace belly, a technology to repair the furnace wall surface profile has been developed. Has been done. For example, as disclosed in Japanese Examined Patent Publication No. 59-47005, a swirl-type spray nozzle is inserted into the furnace when the blast furnace is in a blast state, and an amorphous refractory is sprayed from the spray nozzle to the inner wall surface of the furnace. Technology has been developed to restore the inner wall surface to the state before the brick was dropped or eroded.

[0003]

[Problems to be Solved by the Invention] Japanese Patent Publication No. 59-4700
The technique disclosed in Japanese Patent No. 5 is an effective method for repairing the wall surface profile in the furnace, but the profile holding period after repairing is limited to a fixed period of about one month due to the restriction of the holding strength of the sprayed material. Therefore, it is necessary to repair the profile for each rest, but it is necessary to reduce the level of the charge to just below the repair site for each rest and to enter the rest (hereinafter referred to as reduced scale rest). Therefore, the amount of increase in the fuel ratio for heat compensation during a quiescent wind increases significantly. In addition, since it takes several days to start up the reduced-scale blast, it is likely to have a great influence on the hot metal production and quality. The present invention
In view of such problems of the conventional techniques, it is an object to solve the above problems by designing a blast furnace structure that does not cause a rapid change in the wall surface profile of the furnace body.

[0004]

Means for Solving the Problems That is, the present invention has been made to solve the above-mentioned problems, and the gist of the present invention is to provide a blast furnace body structure constructed with iron shell The inner wall of the blast furnace is characterized in that a stave for cooling the iron skin is installed on the inner wall surface of the furnace.

[0005]

Function: A stave for cooling the iron shell is installed inside the iron shell of the blast furnace furnace body constructed of conventional iron shell, and bricks are piled up inside the furnace of the stave to form the inner wall of the blast furnace furnace. After burning, the furnace wall surface profile of the blast furnace changes due to the falling of bricks, abrasion, erosion, etc., causing a sudden change in the furnace height direction of the cross-sectional area of the furnace wall surface, resulting in unevenness in the furnace wall surface profile. As a result, the smoothness of the wall surface profile in the furnace is reduced. The main reason for this is the abrasion, erosion and falling of bricks. If the wall surface profile of the furnace in the blast furnace is smooth, the ore and coke charges alternately charged in layers from the top of the furnace will fall while maintaining the layered structure, but the bricks will fall off or erode and the furnace body breaks. When the smoothness of the furnace wall surface profile decreases due to the sudden enlargement or reduction of the area or the exposure of protrusions, the mixing equipment is formed near the inside wall surface of the furnace where the smoothness has decreased, and the gas flow changes around the periphery. ,slip,
Anomalies in the operation will be reduced due to irregular loading of the charge.

In the blast furnace body structure in which the inner surface of the stave is attached as the inner wall surface of the blast furnace, that is, in the blast furnace body structure in which the inner surface of the stave is the inner wall surface of the blast furnace in the bosh portion from the shaft portion and bricks are not stacked on the inner surface of the stave. In this case, there is no change in the wall surface profile inside the furnace due to the falling of bricks, erosion and wear. It is expected that the inside wall profile of the furnace will change due to wear of the stave, but the cooling capacity of recent staves has improved and the wear rate of the stave is as small as several tens of mm or less a year. The change is small. In the case of a blast furnace furnace body structure in which a stave with as few irregularities on the stave surface as possible is attached as a blast furnace furnace body wall surface, it is possible to eliminate the formation of a furnace wall mixed layer due to a sudden change in the furnace body profile and projections.
It is possible to remove one of the major factors that make the blast furnace operation uneasy and low.

Here, as shown in FIG. 2, the protrusion on the stave is installed for the purpose of supporting the bricks 16 piled on the front surface of the conventional stave and protecting the corners from wear (installation of the cooling pipe 17). It is a protrusion called a stave 18, and the protrusion length of this protrusion is 300 mm to 200 mm.
mm. In the case of the blast furnace furnace body structure in which the stave is attached as the inner wall surface of the blast furnace, it is not necessary to support the bricks, so that "the protrusion of" can be made as small as possible. Since it is possible to suppress the formation of the mixed layer formed on the wall surface, it is possible to eliminate the instability of the operation due to the peripheral change of the gas flow, the slip, the improper dropping of the charge, and the like.

In the stave blast furnace, in general, the operation is often stabilized in the latter half of the life of the blast furnace in which the bricks on the front surface of the stave fall off and the "parts" of the stave are worn to reduce irregularities on the stave surface. This is because there is no sudden change in the furnace wall surface profile in the furnace height direction at this time, and the unevenness of the stave surface is reduced, so that the formation of the furnace wall mixed layer is suppressed. Stabilization of the wall surface profile in the furnace is one of the important factors in stabilizing the operation of the blast furnace.In the conventional blast furnace furnace structure, there is a concern that the cooling pipe may be damaged due to the wear of the stave surface, and the stave surface of the stave surface may be damaged. Although bricks are piled on the front side, recent staves with significantly enhanced cooling capacity do not require brick piles at the time of burning.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific description will be given based on embodiments shown in the drawings. The method of the present invention is a method based on the knowledge obtained from the experimental results described below. The present inventors conducted an experiment using a model device having a vertical cross-sectional structure as shown in FIG. 3 and having a size of 1/20 scale of an actual blast furnace. The hearth diameter of this model device is 690 mm, the furnace belly diameter is 753 mm, and the effective height from the tuyere to the upper part of the shaft is 1217 mm. In addition, heat-resistant glass was attached to the front of the model device so that the descending behavior of the pseudo-ore having a melting point of 120 ° C. simulating coke or sintered ore could be observed.

Pseudo ore 6 and coke 7 were alternately charged in layers from bell 8 on the upper part of the model device through movable armor 9. On the other hand, heated air at a maximum of 180 ° C is blown from the 18 tuyere 10 at the bottom of the device, and the particle size is 2 to 4 m.
The moke coke 7 and the pseudo ore 6 having a particle size of 1 to 5 mm were carried to the lower hopper by the six rotary feeders 12 provided immediately below the raceway 11, and further discharged into the closed chamber by the tubular conveyor 13. In this blast furnace model device, a pressure gauge and a hot-wire anemometer were installed on the furnace wall surface or inside the furnace to detect the air permeability in the furnace, the stress state near the furnace wall, and the gas flow, respectively. Colored coke was charged as a tracer for isochronous lines for detection, and at the same time, normal (black) coke mixed with about 10% of colored coke was charged for detecting the falling behavior of the charged particles.

Example 1 A blast furnace model of the method of the present invention shown in FIG. 1, specifically, assuming a blast furnace body structure in which the inner surface of a stave is attached as a blast furnace body wall surface, the furnace body wall surface is made of iron. Assuming a blast furnace model with a shaft angle of 82 ° and a morning glory angle of 81 ° and a blast furnace furnace body structure in which the conventional shaft part shown in FIG. 5 and 6 show changes in gas pressure fluctuations in the blast furnace model in which the mixture 14 of stearic acid and sand having a melting point of 60 ° C. is lined on the inner wall surface of the furnace.

As shown in FIG. 6, assuming a conventional blast furnace body structure in which bricks are piled up, a mixture of stearic acid and sand having a melting point of 60 ° C. is formed on the inner wall surface of the furnace from the central part of the shaft to the bosh part and below. In the case of the blast furnace model lined with, the gas pressure fluctuation in the initial stage of the experiment is the same as the gas pressure fluctuation in the case of the blast furnace model of the method of the present invention shown in FIG. 5, but after several tens of minutes, due to the blowing of heated air. As the temperature of the inner wall of the furnace rises, the mixture of stearic acid and sand forming the inner wall of the furnace melts.
When it collapses, the furnace wall is eroded below the center of the shaft and the gas pressure fluctuation increases significantly. It is presumed that this is because a mixed layer was formed in the vicinity of the furnace wall due to the erosion of the furnace wall in the middle part of the shaft. On the other hand, as shown in FIG. 5, in the case of the blast furnace model of the method of the present invention, the smoothness of the inner wall surface of the furnace is maintained and the inner wall surface of the furnace does not change. There is almost no change.

(Embodiment 2) FIG. 7 shows a conventional blast furnace structure in which bricks are laid and protrusions are formed after brick erosion. An experiment was carried out in a blast furnace model in which a protrusion 15 was installed on the inner wall surface of the bosh from the shaft portion and a mixture of stearic acid having a melting point of 60 ° C and sand was lined on the upper portion of the projection 15, and stearic acid FIG. 8 shows gas pressure fluctuations after the sand mixture 14 is melted / collapsed to expose the protrusions. Here, the thickness of the protrusion is 0 mm (converted value of actual furnace 0 mm), 2.5 mm (converted value of actual furnace 50 mm),
5 mm (real furnace converted value 100 mm), 7.5 mm (real furnace converted value 150 mm), 10 mm (real furnace converted value 200 mm)
I changed it.

As shown in FIG. 8, the thickness of the protrusion is 5 mm.
At the actual furnace conversion value of 100 mm, the gas pressure fluctuation decreases,
When the thickness of the protrusion is 2.5 mm (the actual furnace conversion value is 50 mm), the gas pressure is significantly reduced. This is because the thickness of the protrusion is 5
This is because the formation of the furnace wall mixed layer formed in the vicinity of the furnace wall is significantly suppressed when the thickness is equal to or less than 100 mm (the actual furnace conversion value is 100 mm). The above examples are results based on model experiments.
In the actual furnace, bricks were worn out during the latter half of the blast furnace life.
After falling off, the stave surface becomes the inner wall surface of the furnace. However, since the cooling capacity of the stave is improved, there is almost no trouble of the stave cooling pipe being damaged. Therefore, the blast furnace body structure with the stave surface as the inner wall of the blast furnace is
Current technology is sufficient.

[0015]

EFFECTS OF THE INVENTION By adopting the blast furnace furnace body structure of the present invention, formation of a furnace wall mixed layer and operational fluctuations such as gas pressure fluctuations and slips caused by a rapid change in the furnace wall surface profile in the furnace height direction are eliminated. The stable operation of the blast furnace can be maintained.

[Brief description of drawings]

[FIG. 1] Assuming a blast furnace body structure in which an inner surface of a stave is attached as a blast furnace body wall surface, the furnace body wall surface is made of iron,
It is the figure which showed the blast furnace model based on this invention.

FIG. 2 is a diagram showing an outline of a conventional stave.

FIG. 3 is a view showing a vertical cross-sectional view of a 1/20 scale model device of a blast furnace.

FIG. 4 Assuming a conventional blast furnace body structure in which bricks are piled up, 60 ° C. is applied from the central part of the shaft to the inner wall surface of the bosh part.
FIG. 3 is a diagram showing a blast furnace model lined with a mixture of stearic acid and sand having a melting point of 1.

FIG. 5 is a diagram showing a time change of shaft pressure fluctuation when pseudo ore and coke are alternately charged in layers in a blast furnace model of a blast furnace body structure of the method of the present invention.

FIG. 6 is a diagram showing a time change of shaft pressure fluctuation when pseudo ore and coke are alternately charged in layers in a blast furnace model having a blast furnace body structure in which conventional bricks are stacked.

FIG. 7 is a view showing a vertical cross section of a blast furnace body structure when protrusions are formed on the inner wall surface of the blast furnace after brick erosion.

FIG. 8: Gas pressure fluctuation and protrusion thickness after the protrusions are exposed when the pseudo ore and coke are alternately layered in a blast furnace body structure in which protrusions are formed on the inner wall surface of the blast furnace after brick erosion It is the figure which showed the relationship of.

[Explanation of symbols]

1 shaft part 2 furnace belly 3 bosh part 4 inner wall of blast furnace with inner surface of stave attached to the blast furnace body wall made of iron 5 iron shell 6 coke 7 sinter 8 bell 9 moveable armor 10 Tuyere 11 Raceway 12 Rotary feeder 13 Tubular conveyor 14 Mixture of stearic acid and sand stuck to iron shell assuming brick erosion 15 Protrusion 16 Brick 17 Cooling pipe 18 "Stave

Claims (1)

[Claims] 1. A blast furnace body structure constructed of a steel shell,
A blast furnace body structure characterized in that a stave for cooling the iron skin is installed on the inner wall of the iron skin to form the inner wall of the blast furnace.