JPH02122015A - Structure of tuyere in furnace - Google Patents

Abstract

PURPOSE:To drastically reduce erosion in circumferential part of a tuyere, to improve eroding balance of the whole furnace wall and to extend the service life of the furnace lining by surrounding the circumferential part of the tuyere with gas cooling type brick and supplying inert gas through fine holes in this brick. CONSTITUTION:The circumferential part of the tuyere 1 is surrounded with the gas cooling type brick 5 arranging plural gas discharging fine holes 6' and formed so as to supply the inert gas G of Ar gas, etc., in this brick 5 from outside of the furnace through a supplying pipe 7. By this method, the gas is supplied into voids in the brick 5 and infiltration of slag into the voids is restrained and also by lowering temp. of the whole brick 5, the corrosion resistance is improved and the eroding speed is drastically reduced and as the eroding balance of the whole furnace wall is improved, the service life of the furnace lining can be drastically extended.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a tuyere structure for a furnace, such as an RH vacuum degassing furnace, which has a tuyere for blowing gas into molten steel.

[Prior Art] The RH vacuum degassing furnace, which is an external refining furnace in a steel factory, has a lower tank 10 as shown in FIG. 12 is immersed in molten steel,
After evacuating the inside of the tank, Ar gas was blown through tuyere 1,
The molten steel in the tank is circulated from the Yn immersion pipe 11 to the immersion pipe 12 for degassing.

Such a lower tank 10 is composed of an iron shell 2, permanent bricks 3, and wear bricks 4, but the area around the tuyere 1 is the part that is most susceptible to erosion due to ablation (wear) of the molten steel. ing.

Therefore, in the past, in order to extend the life of the furnace, the construction thickness of the wear bricks 4 around the tuyere 1 was made about twice that of other general walls, or bricks made of different materials were used. We are working to improve the balance of erosion throughout the furnace wall.

[Problems to be solved by this invention]

However, even if the construction thickness is increased, the erosion loss around the tuyere is still large and the erosion loss cannot be balanced, and further increasing the construction thickness has many problems in terms of strength and relationship with the furnace wall structure. Furthermore, even if bricks made of different materials are used, satisfactory corrosion resistance and spall resistance cannot be obtained around the tuyere.

This invention was made in view of these circumstances,
The purpose is to create a furnace tuyere structure that can reduce melting damage around the tuyere and improve the melting balance of the entire furnace wall, regardless of the material of the bricks and with a relatively simple brick structure. It is about providing.

[Means to solve the problem]

In the tuyere structure according to the present invention, the tuyere l is surrounded by a gas-cooled brick 5 provided with a large number of gas discharge holes 6, and Ar gas is supplied to the gas-cooled brick 5 from the outside of the furnace through a supply pipe 7. It is configured by supplying an inert gas C such as.

The gas discharge holes 6 may be formed so as to introduce an inert gas from outside the furnace to uniformly cool the bricks 5 as a whole and to supply the inert gas to the pores of the bricks 5. It is preferable to arrange a large number of them parallel to the inside-outside direction of the furnace and at equal intervals in the cross-sectional direction.

[For production]

Refractory? 8 claws progress when the refractory itself becomes high temperature and its fire resistance deteriorates due to infiltration of slag, etc., but in the present invention, gas-cooled bricks 5 are installed around the tuyeres where molten steel moves rapidly. Since the inert gas G is supplied to the bricks 5 through the pores 6, the gas is supplied to the pores of the brick, suppressing the infiltration of slag etc. into the pores, and the entire brick is It is cooled by gas, which improves corrosion resistance and significantly reduces the melt member rate.

〔Example〕

As shown in Fig. 1, this is an example applied to the lower tank IO of an RH vacuum degassing furnace, and the thickness of the 4° wear brick around the tuyere 1 is approximately twice as thick as before. The tuyere l is surrounded by gas-cooled bricks 5 to form a tuyere structure.

This gas-cooled brick 5 is a rectangular parallelepiped with the same length as the thickness of the wear brick 4, and as shown in FIGS. A large number of holes 6 are provided. The pores 6 may be formed during the manufacture of the brick as shown in FIG. 2, or by dividing the brick 5 and forming grooves 6 on the surface of the divided brick, as shown in FIG. death,
The pores 6 may be formed by overlapping them.

In addition, the pores 6 are arranged evenly, and their diameter is set to 0.2 to 0.3 mm in consideration of gas permeability and intrusion of molten steel, etc., and the installation interval is determined in consideration of cooling performance, etc. 5~1 Ona
It is better to set it to a. Moreover, since the material of the brick 5 is provided with pores, it is preferable to use MgO-C, mag-black, or the like.

Ar is applied to the back side of such wear brick 5 through the supply pipe 7.
Although an inert gas G such as a gas is supplied, the outside of the furnace of the wear brick 5 is covered with a box-shaped steel cover 8 in order to equalize the pressure and prevent gas leakage from the brick pores. This coverage range may be about 30% of the side surface, since there is a risk of brick melting and gas leakage at the tip.

During operation, 10 to 5 per piece of such wear brick 5
01! / sin of inert gas is flowed to suppress infiltration of slag etc. into the pores of the brick 5, and to improve corrosion resistance by lowering the temperature of the entire brick 5.

This gas discharge amount is because if the gas flow rate is too fast, gas will not be sufficiently supplied into the pores. 2-3 after discharging 8 steel
It is effective to the extent that the surface of the brick turns pale black in minutes due to cooling.

Further, it is preferable to provide a pressure equalizer 9 outside the furnace to supply the inert gas G evenly to each brick. Furthermore, when not in operation, it is preferable to discharge inert gas G at high pressure (5 to 7 kg/c4) for several minutes to ensure air permeability of the pores 6.

The following table is an example comparing the melting tJl speed around the tuyere of the present invention and the conventional example.

Comparison of erosion rates As is clear from this table, conventionally, even if the thickness of the bricks around the tuyere was twice that of the general side wall, the erosion balance of the furnace wall could not be maintained. The erosion loss around the mouth is reduced to the same level as that of ordinary walls, and the erosion balance can be greatly improved.

Although the lower tank of the RH vacuum degassing furnace has been described above, it goes without saying that the present invention is not limited to this and can be applied to a furnace having a tuyere for blowing gas into molten steel.

〔Effect of the invention〕

As mentioned above, in the tuyere structure according to the present invention, the tuyere is surrounded by gas-cooled bricks, and inert gas is supplied to the bricks through the pores, so that the tuyere structure can be used regardless of the material of the bricks. In addition, the relatively simple brick structure by 4 degrees can significantly reduce melting loss around the tuyere and improve the melting loss balance of the entire furnace wall. This makes it possible to significantly extend the life of the furnace compared to conventional methods.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the tuyere structure of a furnace according to the present invention, FIGS. 2 and 3 are perspective views showing an example of the gas-cooled brick,
FIG. 4 is a sectional view showing a conventional example. ■・・・Tuyere, 2...Skin 3...
・Permanent brick, 4...Wear brick 5...
・Gas cooling type brick 6... Gas discharge pore 7... Supply pipe, 8... Steel cover 9.
・・・・・・Pressure equalizer diagram

Claims (1)

[Claims] (1) In the tuyere structure of a furnace that performs treatment by blowing gas into molten steel from the tuyeres, the tuyeres are surrounded by gas-cooled bricks provided with many gas discharge pores, and this gas-cooled type A tuyere structure for a furnace, characterized in that it is configured by supplying inert gas to the bricks from outside the furnace through a supply pipe.