JPS5855235Y2 - Seal structure of skirt part in steelmaking furnace - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a seal structure of a skirt portion in an oxygen steelmaking furnace equipped with an unburned exhaust gas recovery device.

Conventionally, when refining molten steel in a steelmaking furnace such as a converter, the composition of the exhaust gas generated in the furnace contains a large amount of components that can be used effectively, and it is already difficult to recover the exhaust gas in an unburned state. It is well known.

This idea involves blowing oxygen into the molten metal in the furnace from above or from the bottom, adjusting the composition of the molten metal in the furnace to the desired product, and performing blowing to ensure an appropriate tapping temperature. Applicable to oxygen steelmaking furnaces.

Oxygen blown into the steelmaking furnace reacts with impurities in the hot metal, such as silicon and phosphorus, forming oxides with them, and the oxides are deposited on the surface of the slag.

On the other hand, the oxygen reacted with carbon in the hot metal to generate carbon monoxide gas (CO gas).

Therefore, the main component in the exhaust gas in an oxygen steelmaking furnace is CO gas based on the decarburization reaction.

The amount of CO gas produced changes in proportion to the decarburization reaction rate.

In the conventional steelmaking method, which uses hot metal for steelmaking from a blast furnace, the charged hot metal contains quite a large amount of impurities, such as silicon and phosphorus. Treatments such as desiliconization and phosphorization were carried out through intervention.

Therefore, during decarburization blowing of molten steel, the influence of slopping caused by the slag cannot be avoided.

Various measures have been proposed to prevent slopping, but it is still difficult to completely eliminate slopping, and the contents of the furnace ejected due to slopping are
It was deposited on the furnace mouth metal fittings.

In an exhaust gas recovery device for an oxygen steelmaking furnace such as a converter, exhaust gas is collected by raising and lowering a skirt.

That is, the skirt is supported by a lifting device and its lower part surrounds the furnace mouth, and the skirt is lowered when collecting exhaust gas, but as mentioned above, if there is deposits on the furnace mouth metal fittings, This caused a gap between the furnace body and the skirt.

If the seal between the furnace body and the flue is incomplete, outside air will enter through the gap, causing various problems in exhaust gas recovery.

On the other hand, apart from the conventional steelmaking method mentioned above, pre-treated hot metal that has removed impurities such as phosphorus, sulfur, and silicon from the blast furnace to a level that does not adversely affect product quality is loaded into the steelmaking furnace. There is a steelmaking method in which steel is poured into a steelmaking furnace and slag is blown in a state where almost no slag is present to carry out a decarburization reaction.

Since there is almost no slag in the steelmaking furnace where this slagless blowing is performed, the above-mentioned slopping phenomenon does not occur.

In the slagless blowing method, the hot metal charged into the furnace has been sufficiently treated to remove silicon, etc., so in an oxygen steelmaking furnace, an intense decarburization reaction occurs immediately after the start of blowing. A larger amount of CO gas is also generated than originally.

Therefore, the CO gas concentration in the generated exhaust gas also increases rapidly,
The gas composition is recoverable, and the exhaust gas can be recovered earlier.

This is the reason why it is required that the sealing properties of the steelmaking furnace mouth and skirt be more completely airtight.

This idea was developed based on the technical background and issues mentioned above, and it was possible to completely seal the furnace mouth and skirt, eliminate the cause of explosion when recovering steelmaking furnace exhaust gas, and improve exhaust gas recovery efficiency. The purpose of this invention is to provide a sealing structure for a skirt portion in a steelmaking furnace that can be expected to be improved.

The gist of this invention, which can effectively achieve the above object, is a seal structure at the lower part of the skirt that is supported by a lifting device and surrounds the furnace mouth of an oxygen steelmaking furnace, and which is attached to the outer periphery of the furnace layer of the steelmaking furnace. A sealing structure for a skirt portion in a steelmaking furnace is provided, characterized in that an engaging portion is provided with which a lower end edge of the skirt engages, and a curtain portion formed by a fluid is formed at the lower end portion of the outer periphery of the skirt.

That is, the feature of this invention lies in the sealing structure of the skirt portion, which is configured such that the lower end edge of the skirt is brought into contact with the shoulder portion of the steelmaking furnace, and a fluid curtain portion is formed to provide an airtight seal.

Hereinafter, the details will be explained based on the drawings showing specific embodiments of this invention.

FIG. 1 shows an example of an oxygen top blowing converter to which the skirt seal structure of the present invention is applied.

In the figure, 1 is a converter, and 2 is a skirt. The skirt 2 is supported by an elevating device (not shown) and is provided to surround the furnace mouth 3, so that when lowered, its lower edge touches the converter 1. It is formed so as to come into contact with the furnace shoulder 4 of the furnace.

Therefore, the contact area between the skirt 2 and the furnace shoulder 4 (part a in Figure 1)
A fluid curtain mechanism is provided.

FIG. 2 is an enlarged view of section a in FIG. 1, illustrating the curtain mechanism at the abutting section.

In the embodiment shown in FIG. 2, an engaging part 5 with which the scars 1-2 engage is provided on the furnace shoulder 4, and a fluid supply pipe 6 is provided along the scars 1-2, and the tip thereof is provided with a fluid supply pipe 6. A header 8 having a nozzle portion 7 is provided surrounding the outside of the skirt 2.

In this seal structure, the scar 1 is connected to the engagement part 5 of the furnace shoulder 4.
Although the structure is such that it can be sealed by coming into contact with the furnace shoulder portion 4 or the skirt portion 2, the fluid curtain completely seals the seal against damage caused by thermal distortion of the furnace shoulder portion 4 or the skirt portion 2.

In the fluid curtain mechanism, the fluid to be applied may be appropriately selected from those that are economically and industrially usable.

Commonly applied fluids include inert gas (N2.A
Examples of gases and liquids such as r, etc.) include water.

When water is used, at the same time as the effect of the water curtain, the cooling effect of the curtain part and the furnace body can be expected as a secondary effect due to the cooling ability of the water.

In the above embodiment, an example of application to an oxygen top-blowing converter has been described, but it goes without saying that a bottom-blowing converter can also be constructed in the same manner.

According to the gas seal structure of the skirt in the steelmaking furnace of this invention, when sealing between the furnace body and the skirt, the skirt is not sealed by the furnace mouth fittings, but by the Since it has a structure that seals at the shoulder,
Unlike the conventional method, there is no effect of deposits deposited on the furnace mouthpiece, and more complete airtightness can be ensured by the curtain effect caused by the fluid.

By applying the seal structure of this invention, the above-mentioned conventional problems can be solved.

Note that the seal structure of this invention has a particularly remarkable effect when performing the slagless blowing described above.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an embodiment in which the seal structure of this invention is applied to an oxygen top blowing converter, and FIG. 2 is an enlarged cross-sectional view of the embodiment at section a in FIG. 1.

Claims (1)

[Scope of utility model registration request] A sealing structure for a lower end of a skirt that is supported by a lifting device and surrounds a furnace mouth of an oxygen steelmaking furnace, wherein an engaging portion is provided on the outer periphery of the furnace layer of the steelmaking furnace with which the lower edge of the skirt engages, and the outer periphery of the skirt is A sealing structure for a skirt portion in a steelmaking furnace, characterized in that a curtain portion formed by a fluid is formed at a lower end portion.