KR101431028B1

KR101431028B1 - Apparatus for melting loss of bottom brick in furnance

Info

Publication number: KR101431028B1
Application number: KR1020120155457A
Authority: KR
Inventors: 권순극; 박종환; 김공영
Original assignee: 주식회사 포스코
Priority date: 2012-12-27
Filing date: 2012-12-27
Publication date: 2014-08-18
Also published as: KR20140085177A

Abstract

The present invention relates to a molten iron loss preventing apparatus for a converter floor span and includes a furnace iron core and a bottom fringe formed on an inner bottom of the furnace iron core, And a gas supply pipe connected to the bottom of the converter and communicating with the interior of the converter, wherein the gas supply pipe includes an outer pipe into which the first inert gas is introduced, and a second inert gas inserted into the outer pipe, And an inner pipe to be blown.

Description

TECHNICAL FIELD [0001] The present invention relates to an apparatus for preventing melting loss of a furnace,

More particularly, the present invention relates to an apparatus for preventing a molten steel from being exposed to a high temperature by forming a mushroom on the upper end of the furnace around the outlet of the converter, And preventing the melting of the inner wall of the transformer.

Generally, in the conversion process, impurities such as carbon, silicon, manganese, phosphorus, sulfur and titanium are oxidized and removed by blowing high-speed oxygen gas through the lance after charging iron and scrap iron, which are main raw materials, into the converter, Slag is formed by adding subsidiary raw materials such as burnt lime, formation, dolomite, and sintered ores during the blowing for the removal of the slag. In such a converter, there is an image-taking furnace that blows only oxygen gas through the upper lance and a low-charge furnace that blows oxygen together with the nozzle cooling gas at the bottom of the furnace, and oxygen is blown through the lance at the top, There is a combined blowing furnace which blows an inert gas to improve the blowing efficiency.

On the other hand, K-OBM method is a kind of compound sintering furnace, which injects oxygen and inert gas in molten steel at a proper ratio of pattern according to carbon concentration in steel to oxidize carbon (C) first than chromium (Cr) Method.

Usually, the blowing step is divided into a decarburization step and a reduction desulfurization step. In the decarburization step, the oxygen / inert gas ratio is changed according to the carbon concentration of the molten steel to increase the oxygen efficiency. That is, in the initial high-carbon region, the rate of decarbonization depends on the amount of oxygen charged, thereby increasing the oxygen intake amount and increasing the inert gas ratio toward the low-carbon region, thereby lowering the PCO (CO partial pressure) and increasing the decarburization efficiency.

After completion of the decarburization step, a large amount of expensive metal oxide generated in the decarburization step is reduced, and a reduction desulfurization step is performed to remove the sulfur component (S) in the molten steel. After the reduction desulfurization step, a slag and a molten steel are simultaneously introduced into a ladle through a furnace in order to perform a ladle operation.

Referring to FIG. 1, a conventional converter 10 is provided with a blowing port 2 for blowing an oxygen / inert gas at the bottom of the converter 10 so that the decarbonization reaction occurs when the diluted gas bubble rises. However, in such a case, the stirring of the molten steel and the slag is so severe that the melting loss with the refractory steel is large. Particularly, due to the intense flow of molten steel around the tuyeres 2 and the exothermic reaction between oxygen and molten steel components, the temperature around the tip of the tuyeres 2 is 2000 to 2200 ° C, which is much higher than the entire furnace temperature (1650 to 1700 ° C) There is a problem that the use life of the converter is shortened due to a serious loss of the melting point of the exhaust gas around the air outlet 2 at the bottom of the converter 10.

Korean Patent Publication No. 2000-0034401 (June 26, 2000)

A problem to be solved by the present invention is to provide a molten loss prevention apparatus with a converter bottom fl ame that can prevent the melting of the converter from being exposed to high temperatures, thereby preventing the melting of the flame.

Another problem to be solved by the present invention is to provide a molten-loss preventing apparatus for preventing the melting of a molten steel and a refractory steel, which can buffer the molten steel and the refractory.

According to an aspect of the present invention, there is provided a method of manufacturing a nonaqueous electrolyte secondary battery, the method comprising: And a gas supply pipe connected to the bottom of the converter and communicating with the interior of the converter, wherein the gas supply pipe includes an outer pipe into which the first inert gas is introduced, and a second inert gas inserted into the outer pipe, The present invention provides an apparatus for preventing melting loss with a converter floor bottom which is provided with an inner pipe to be blown.

Here, the appearance is further characterized in that the LNG gas is blown, the blowing rate of the first inert gas is 250 Nm³ / Hr, and the blowing rate of the LNG gas is 20 to 40 Nm³ / Hr do.

The first inert gas may be nitrogen or argon.

The apparatus includes a first supply pipe connected to the outer pipe to supply the oxygen and the second inert gas to the inner pipe; A sealing member sealing a space formed between the outside of the lower end of the inner tube and the inside of the outer tube; And a second supply pipe communicating with a space formed between the outer tube and the inner tube to supply the first inert gas to the space.

The effect of the melting prevention device with the converter floor bottom according to the present invention will be described as follows.

First, there is an advantage that a mushroom generated at the upper part of the tuyeres around the tuyere of the converter can prevent the tuyeres from being exposed to high temperatures, thereby preventing the melting of the tuyeres.

Second, there is an advantage that a mushroom generated at the upper part of the furnace around the tuyere of the converter serves as a buffer between the molten steel and the inner part of the furnace, thereby preventing the melting of the furnace.

1 is a block diagram of a conventional K-OBM converter.
2 is a configuration diagram of a molten loss prevention apparatus with a converter floor bottom according to an embodiment of the present invention.
Fig. 3 is a view showing a double tube structure of the gas supply pipe of Fig. 2; Fig.
4 is an enlarged view of a state where a gas supply pipe is connected to a melting prevention device with a converter floor bottom according to an embodiment of the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, referring to the accompanying drawings, an embodiment of a molten loss prevention apparatus with a converter floor bottom according to the present invention will be described.

FIG. 2 is a configuration diagram of a molten loss prevention apparatus for a converter floor according to an embodiment of the present invention, FIG. 3 is a view illustrating a double pipe structure of the gas supply pipe of FIG. 2, and FIG. In which a gas supply pipe is connected to a molten loss prevention device with a converter bottom flue. Referring to Figs. 2 to 4, a description will be made of a molten loss prevention apparatus with a converter floor bottom according to an embodiment of the present invention. The melting prevention apparatus with the converter floor bottom according to the present embodiment includes a converter 10 and a gas supply pipe 30.

Referring to FIG. 2, the converter 10 is constructed such that an upper portion thereof is opened to contain molten steel therein, and a blowing hole 14 through which a gas supply pipe 30 can be inserted is formed at the bottom of the converter 10 A non-woven fabric 11 surrounding the outside of the converter 10, and a woven fabric 12 built inside the non-woven fabric 11. The inner flue 12 is provided to prevent direct contact of the flameproof flap 11 with the molten steel 1 at a high temperature and includes a sidewall flap 12a and a flameproof flap 11 formed on the inner sidewall of the flameproof flap 11, And a bottom flame 12b formed on the inner bottom of the frame.

The gas supply pipe 30 is inserted into the air outlet 14 and communicates with the inside of the converter 10 and has a double pipe structure of an outer pipe 32 and an inner pipe 34. In this gas supply pipe 30, a gas necessary for decarburization is blown. In particular, when the molten steel 1 is immersed, a gas of a predetermined pressure or more is always blown in order to prevent molten steel from flowing out due to the static pressure of iron.

A first inert gas such as nitrogen, argon, or the like is introduced into the outer tube 32, and the molten steel is cooled on the upper surface of the bottom tread 12b around the tuyeres 14 by the cooling ability of the first inert gas, A mushroom 40 is created. Due to the mushroom 40, the bottom flue 12b is not directly exposed to the high-temperature molten steel but also acts to buffer the impact caused by the molten steel swirl so that it is not directly transmitted to the bottom flue 12b. In addition, the outer tube 32 protects the inner tube 34 from the hot molten steel by blocking direct delivery of the molten steel to the inner tube 34 inserted in the outer tube 32.

The LNG gas is exothermic when it is burnt in the atmosphere but dissociates when it is blown into the molten steel and absorbs the endothermic reaction. The LNG gas is cooled to about 4 times as much as that of argon and nitrogen gas The ability to manage an adequate level of mushroom without significantly increasing the apparent flow rate. At this time, it is preferable that the blowing flow rate of the first inert gas is 250 [Nm³ / Hr] and the blowing flow rate of the LNG gas is 10 to 50 [Nm³ / Hr]. Here, the reaction formula of the LNG gas dissociated in the molten steel is as follows.

CH4 - > C + 4H

The inner pipe 34 is inserted into the outer pipe 32, and oxygen and the second inert gas are introduced. At this time, the second inert gas may include argon (Ar), nitrogen (N2), or the like.

Specifically, the oxygen and the second inert gas blown through the inner pipe 34 react with the metal in the molten steel to perform the oxidation reaction, and the first inert gas and the LNG gas blown through the outer pipe 32 pass through the outlet 14 So that a mushroom 40 is formed on the upper surface of the bottom flue 12b around the blowing port 14. [ At this time, the second inert gas of 250 [Nm3 / Hr] blown into the outer surface acts as a base gas for preventing the outflow of molten steel against the iron static pressure, and the LNG gas of 10 to 50 [Nm3 / Hr] And is used as a gas for regulating the thickness or size of the mushroom 40 as well as generating the mushroom 40. In this case, the optimum thickness of the mushroom, which can protect the bottom softened trowel 12b from high-temperature heat and alleviate shock caused by molten steel swirling, is 40 to 90 [mm].

The mushroom 40 thus produced is brought into direct contact with the bottom flue 12b in the high temperature region A formed on the upper portion of the tuyeres 14 by the reaction between the oxygen taken in through the inner pipe 34 and the molten steel 1 And minimizes the melting loss of the bottom flue 12b by acting as a buffer against the molten steel vortex.

Referring to FIG. 4, the melting prevention apparatus with the converter floor bottom according to the present embodiment may further include a first supply pipe 33, a second supply pipe 35, and a sealing member 38.

The first supply pipe 33 is connected to the outer pipe 32 and supplies oxygen and a second inert gas to the inner pipe 34.

The sealing member 38 seals a space formed between the outer surface of the lower end of the inner tube 34 and the inner surface of the outer tube 32 so that the oxygen and the second inert gas supplied from the first supply tube 33 pass through the inner tube 34, And the LNG gas is introduced into the outer pipe 32 together with the first inert gas or the first inert gas supplied from the second supply pipe 35.

The second supply pipe 35 communicates with the space formed between the outer pipe 32 and the inner pipe 34 to supply the LNG gas to the outer pipe 32 together with the first inert gas or the first inert gas.

This has the effect of shortening the length of the inner tube 34 inserted into the outer tube 32.

Hereinafter, the present invention will be described more specifically by way of examples.

(Example)

In this embodiment, when the flow rate of the LNG gas is changed while the flow rate of the first inert gas blown into the converter 10 through the outer tube 34 is fixed at 250 (Nm³ / Hr) The thickness of the mushroom formed on the top surface of the bottom was measured, and the results are shown in Table 1 below.

The first inert gas
Flow rate (Nm³ / Hr) LNG gas flow rate
(Nm³ / Hr) The first inert gas
Conversion (Nm³ / Hr) Increased cooling capacity
(%) Generated Mushroom
Thickness (mm) Remarks 250 10 250+ (10 * 4) = 290 Equivalent level 20 to 50 mm Mushroom thickness over-applied 250 20 250 + (20 * 4) = 330 10 40 to 70 mm Maintain the same flow rate (Flow rate adjustment for mushroom thickness variation) 250 30 250+ (30 * 4) = 370 20 50 to 80 mm 250 40 250+ (40 * 4) = 410 30 60 to 90 mm 250 50 250 + (50 * 4) = 450 50 80 to 100 mm Mushroom Thickness Application

As shown in Table 1, when the flow rate of the first inert gas is 250 (Nm³ / Hr) and the flow rate of the LNG gas is 20 to 40 (Nm³ / Hr), the generated mushroom has an optimum thickness of 40 To 90 (mm).

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims and their equivalents. Of course, such modifications are within the scope of the claims.

1: molten steel 10: converter
11: Noh Chee Pyo 12: My Hwa Yeon
2, 14: blowing port 12a:
12b: bottom opening and 3, 30: gas supply pipe
32: Appearance 33: First supply pipe
34: Inner pipe 35: Second supply pipe
38: Sealing member 40: Mushroom

Claims

A converter including a bottom flue formed at an inner bottom of the furnace iron furnace and containing molten steel therein;
And a gas supply pipe connected to the bottom of the converter and communicating with the inside of the converter,
The gas supply pipe
An inner tube into which the first inert gas and the LNG gas are introduced, and an inner pipe inserted into the outer tube to receive oxygen and a second inert gas,
Wherein the thickness of the mushroom generated on the upper surface of the bottom of the gas supply pipe is adjusted according to a blowing rate of the LNG gas.

The method according to claim 1,
Wherein the blowing flow rate of the LNG gas is 20 to 40 Nm³ / Hr.

The method of claim 2,
Wherein the first inert gas is nitrogen or argon.

The method according to claim 1,
The melting prevention device with the converter bottom flame
A first supply pipe connected to the outer pipe to supply the oxygen and the second inert gas to the inner pipe;
A sealing member for sealing a space formed between the outer side of the lower end of the inner tube and the inside of the outer tube;
And a second supply pipe communicating with a space formed between the outer pipe and the inner pipe to supply the first inert gas to the space.

The method of claim 2,
Wherein the blowing flow rate of the first inert gas is 250 Nm³ / Hr.