JPS629316Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a melting and refining furnace or metallurgical vessel that improves the durability of the furnace bottom by improving the protection of the tuyere tubes and tuyere bricks at the hearth bottom of the melting and refining furnace or metallurgical vessel. This relates to the hearth brick structure.

A conventional brickwork structure with a tuyere tube in a melting and refining furnace or a metallurgical vessel will be explained with reference to FIGS. 1 to 5.

FIG. 1 is a longitudinal cross-sectional view of a composite blowing converter, which is an example of a melting and refining furnace using a conventional brickwork structure with a tuyere tube.

As shown in FIG. 1, in a melting and refining furnace or a metallurgical vessel that performs bottom blowing, for example, a composite blowing converter 1, a tuyere pipe 3 is opened in the hearth bottom 2, and molten steel 4 is passed through the tuyere pipe 3. It has a structure in which a blowing gas 5 consisting of pure oxygen gas and powder, and a cooling gas 6 for protecting the tuyere are blown into it.

In addition, 7 is a lance for oxygen blowing.

In this combined blowing converter 1, the bottom 2, especially around the tuyere tube 3, is subject to severe wear and tear, and the life of the bottom is short compared to the furnace wall 8, so there is also a type in which the bottom can be replaced.

FIG. 2 shows a cross-sectional view of the tuyere tube 3. As shown in the figure, the tuyere pipe 3 has a double pipe structure, and blowing gas and powder are blown from the innermost side, and cooling gas is blown from the outer passage 9. Note that 10 is called an inner tube, and 11 is called an outer tube, and a ceramic pipe 12 is inserted inside the inner tube 10.

Here, FIG. 3 shows a conventional furnace bottom brickwork structure near the tuyere.

In the figure, reference numeral 16 denotes a hearth bottom plate, which has a permanent tension brick 15 fixed thereon, a tuyere brick 13 through which the tuyere pipe 3 is inserted, and lining bricks 14, 14 adjacent thereto, on which bricks are stacked. The structure is composed.

As shown in Fig. 4, in the bottom 2 of a combined blowing converter, a conide-shaped solidified iron 17 is placed directly near the tuyere.
is generated by the cooling gas 6. This solidified iron 17 has the effect of protecting the tuyere pipe 3 and the tuyere brick 13 from various harsh physical conditions such as stirring of slag and molten steel, high temperature due to being close to the fire point, and sudden temperature changes during operation. The technology for extending the life of the tuyere is to control the cooling capacity of the cooling gas so that the solidified iron 17 is always kept in a circular shape of almost constant size.

However, in the conventional brickwork structure, the furnace bottom plate 16 is damaged due to expansion and contraction of the lining bricks 14 during operation, movement of the lining bricks 14 when the converter is tilted, etc.
By deforming the tuyere pipe 3 fixed to the inner pipe 10
This crushed the gap between the outer pipe 11 and the ceramic pipe 12, causing poor production of solidified iron 17 and mechanical spalling of the bricks.

If the above trouble occurs, the protective effect of the tuyere pipe 3 and the tuyere brick 13 will be lost, and in severe cases, it will cause sudden damage as shown in Figure 5, which may lead to an extremely short life and an accident that will require the reactor to shut down. This may occur in some cases.

As a solution to this problem, we considered a brickwork structure in which only the tuyere bricks 13 are embedded in the permanent tension bricks 15 as shown in FIGS. 6a and 6b. That is, to explain based on FIGS. 6a and 6b, 16 in the figure is a hearth bottom plate, 18 is a ring-shaped iron plate permanent tension presser that is integrated with the hearth bottom plate 16 and surrounds the permanent tension bricks 15,
The permanent bricks 15 are thereby fixed. A tuyere brick 13 is fixed onto this permanent tension brick 15. Note that 19 is a furnace wall shell, and 20 is a monolithic refractory. The lower part of the tuyere brick 13 is embedded in the recess of the permanent tension brick 15, thereby protecting the tuyere pipe 3 from expansion, contraction, etc. of the furnace bottom lining brick 14.

However, with this structure, the bad one is 100 ~
Over 15% of the troubles occurred during 200 blowings.

The main causes of this trouble are poor production of the solidified iron 17 that protects the area around the tuyere pipe 3, leakage of cooling gas,
This could be due to a blowing failure due to a blockage in the cooling gas passage.

When such trouble occurs, the damage rate of the bricks around the tuyere pipe 3 increases significantly, and the damage rate is 300 to 400
As shown in FIG. 5, the length of the tuyere tube is locally shortened by the repeated blowing. In this case, the tuyere pipe 3 must be closed with a refractory, which will determine the life of the bottom of the composite blowing furnace.

Therefore, the purpose of this invention is to provide a furnace bottom brick structure with a tuyere tube that provides a protective effect for the tuyere tube by reducing the mechanical stress applied to the tuyere tube. shall be.

According to the present invention, the above purpose is to provide a tuyere in a recess of 1/10 to 5/6 of the thickness of the permanent brick fixed by the hearth bottom plate and 150 mm or more in width. Mechanical stress applied to the tuyere tube can be reduced by creating a brickwork structure at the bottom of the melting and refining furnace or metallurgical vessel, in which the lower part of the tuyere brick through which the tube is inserted and the adjacent lining brick is embedded. So it is achieved.

The present invention will be explained below with reference to examples.

FIG. 7 is a diagram showing an embodiment of the present invention. In the figure, 15 is a permanent lining brick, on which a tuyere brick 13 and an adjacent lining brick 2 are placed.
1 and 21 are fixed. Said tuyere brick 13
The lower portions of the adjacent lining bricks 21, 21 are embedded in the recesses 23 of the permanent lining bricks 15, thereby allowing the bottom lining bricks 14 to expand,
This protects the tuyere tube 3 from shrinkage and the like.

The material of the bricks lining the hearth is magnesia.
Although carbonaceous material is used, reduction fired products of magnesia and carbonaceous materials are also available.
It may be dolomitic, magnesia/calcareous, magnesia/chromium, etc. Furthermore, as the permanent brick, fired magnesia or the like is used. An example of typical physical property values of these bricks is shown in Table 1.

Since the absolute value of the mechanical stress applied to the tuyere tube 3 during operation of the combined blowing converter 1 cannot be measured, based on the above results, it is empirically determined that the tuyere length is 150 mm including the tuyere brick 13.
It will not be effective if it is not filled with a width greater than this.

Furthermore, the purpose of embedding the tuyere bricks 13 in the recesses 23 of the permanent bricks 15 is to prevent the tuyere bricks 13 from falling off by the permanent bricks 15. Less effective. Therefore, the amount of embedding was approximately 1/10 to 5/6 of the thickness of the permanent brick.

In this way, the furnace bottom brick structure shown in Figure 7 maintains a lifespan of more than 1000 tuyeres, and the frequency of tuyere occurrence during that time is less than 1%, which is drastically reduced compared to the conventional structure.
The durability has tripled. Further, by sealing the joints with joint mortar 22 or the like, the backflow of gas through the gap between the tuyere pipe 3 and the tuyere bricks 13 was reduced. This improves gas efficiency and eliminates the gas leakage through the gap between the lining bricks 14 and the permanent bricks 15, which is thought to cause the peeling of the sprayed repair material and the furnace bottom. It can also prevent the bricks from falling off suddenly at the end of their use.

As explained above, according to the present invention, the permanent tension bricks are fixed by the hearth bottom plate, and about 1/10 to 5/6 of the thickness of the permanent tension bricks are embedded in it with a width of 150 mm or more including the tuyere bricks. By creating a brickwork structure consisting of a tuyere brick that penetrates the refining tuyere pipe and a lining brick adjacent to it, the mechanical stress applied to the tuyere pipe can be reduced, thereby protecting the tuyere pipe. can give an effect.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of a converter using the combined blowing method, Figure 2 is a cross-sectional view of a tuyere tube, Figure 3 is an example of a conventional brickwork structure, and Figure 4 is a combined blowing converter. Figure 5 shows the situation near the tuyere at the bottom of the furnace, Figure 5 shows rapid damage to the tuyere, Figures 6a and b show an improved version of the conventional structure, and Figure 7 shows the structure of the present invention. It is a figure showing one example. Explanation of the symbol, 1; Composite blowing converter, 2; Hearth bottom,
3; Tuyere tube, 4; Molten steel, 5; Blowing gas, 6; Cooling gas, 7; Oxygen blowing lance, 8; Furnace wall, 9; Passage, 10; Inner tube, 11; Outer tube, 12; Ceramic Made pipe, 13; Tuyere brick, 14; Hearth lining brick, 15; Permanent tension brick, 16; Furnace bottom plate, 17; Solidified iron, 18; Permanently tensioned metal fittings, 1
9; Furnace wall shell, 20; Monolithic refractory, 21; Lining brick, 22; Joint mortar, 23; Recess.

【table】

Claims (1)

[Scope of utility model registration request] In the brickwork structure of the furnace bottom of a melting and smelting furnace or metallurgical vessel having a tuyere tube attached to the furnace bottom plate and a refractory hearth lining formed by laying bricks, a permanent 1/10 to 5/6 of the thickness of the permanent tension brick formed on the tension brick
A furnace bottom brick structure for a melting and refining furnace or metallurgical vessel, consisting of a tuyere brick through which a tuyere pipe is inserted and the lower part of an adjacent lining brick embedded in a recess with a depth and width of 150 mm or more.