JPH055840U - Bottom blown tuyere - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent damage to refractory materials around the tuyere of the bottom-blown tuyere used for the blown tuyere used in continuous refining furnaces. [Configuration] A reaction gas discharge pipe 5 is installed so as to penetrate in the longitudinal direction of the tuyere. On the tip side of the tuyere, the periphery of the discharge pipe 5 is surrounded by the breathable refractory 3 for circulating the cooling gas, and on the base end side of the tuyere, the periphery of the discharge pipe 5 is surrounded by the non-breathable refractory 10. A cooling gas supply pipe 7 is provided through the non-breathable refractory material 10 to the breathable refractory material 3, and a cooling gas reservoir chamber 8 is provided at the boundary between the breathable refractory material 3 and the non-breathable refractory material 10. To provide. The cooling gas supply pipe 7 is connected to the storage chamber 8. [Effect] Since the cooling gas flowing through the breathable refractory at the time of blowing is uniformly ejected from the tip surface of the tuyere, mushrooms can be stably formed on the tip surface of the tuyere and its vicinity. .. That is, the cooling gas is ejected in a wide range, a large non-contact space is created between the molten metal and the breathable refractory, and the refractory is protected. As a result, the refining reaction in the furnace is very stable, and the wear of the hearth also progresses on average, so that the total life of the refractory is extended.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a bottom blowing tuyere used for a pretreatment furnace for molten pig iron, a secondary refining furnace, a converter, a continuous refining furnace, and the like.

[0002]

[Prior Art]

 Conventionally, when refining molten metal, etc., a refractory for gas injection (tuyere) made of refractory is provided at the bottom of the converter to stir the molten metal for the purpose of decarburization refining or reaction promotion. It is widely practiced to blow various gases.

As the tuyere, a required number of gas discharge passages are formed of a refractory material in which the gas discharge passages are provided in the longitudinal direction, and the gas discharge passages defined on the base end side of the tuyere body. It is known to have a gas distribution chamber communicating with the. Then, in order to improve the strength of the main part of the tuyere made of this refractory material, it is known to fit a metal tube of stainless steel or the like into the gas discharge passage.

Further, conventionally, a double-pipe made of metal is used as the metal tube, and a tuyere of a system in which a gas or a liquid for cooling is supplied from an inner tube to a reactive gas outer tube has a bottom blowing converter. Is used for. Further, as tuyere, those made of porous refractory and those made by bundling thin tubes such as stainless steel are known.

FIG. 2 is a cross-sectional view showing a conventional bottom-blowing tuyere A, in which a hole 2 is bored in a furnace bottom refractory 1 and the bottom-blowing tuyere A is inserted. This bottom blown tuyere A is provided with an oxygen introduction pipe 5 having an oxygen introduction port 4 inside, and a coolant introduction pipe 7 having the oxygen introduction pipe 5 fitted therein and having a coolant introduction port 6 on the inner side. As the coolant gas _{(Ar, N 2, CO,} C O 2 , etc.) other, kerosene, LPG is also used.

In such a tuyere, it is necessary to attach and generate a mushroom 12 having a protective effect on the tuyere A and the refractory 1 around the tuyere. The mashroom 12 is a solidified metal block having an oxygen outflow hole in the center and a large number of fine coolant injection holes around the oxygen outflow hole.

[0007]

[Problems to be solved by the device]

 In such a tuyere, depending on the formation state of the mushrooms, the refractory material in the tuyere and the surrounding area is significantly damaged, and fluctuations in the supply state of oxygen and coolant, clogging, etc. are likely to occur, resulting in unstable operation. And shortening the life of the hearth.

For example, in the conventional example shown in FIG. 2, although LPG can be used and the heat of vaporization thereof can be used for the cooling action, it is necessary to prevent the coolant outlet 6a from being blocked. The clearance (coolant injection port 6a) between the pipe (oxygen introducing pipe 5) and the outer pipe (coolant introducing pipe 7) must be set small. For this reason, the cooling effect is locally concentrated only at the tip of the tuyere, so an iron ingot (mushroom) is formed in the upper part of the tuyere, but during the formation process, it is blown due to changes in the gas flow rate, the mixing state in the furnace, etc. Due to the spouting of pure oxygen and coolant, normal mushroom formation may not be realized, and spouting of oxygen gas may sometimes be lateral or reverse, leading to localized damage to the hearth (uneven melt loss 13). .. At times, the flow of blown oxygen and the coolant is blocked, and in extreme cases, blockage occurs, destabilization of the refining reaction and damage to the hearth due to reduced cooling capacity. Once a normal mushroom is formed, stable operation is possible after that, but especially the operating conditions for the initial mushroom formation require a very high level of know-how.

Further, there is a tuyere of a system using a porous refractory, but it is severely damaged when a reactive gas such as oxygen is supplied, and is limited to the purpose of using an inert gas.

Further, even in tuyere of a method of bundling thin tubes of stainless steel or the like and supplying a reactive gas such as oxygen from this, the use of the reactive gas such as oxygen causes a large damage to the tuyere. There is a limit. There is also a problem in the stability of gas supply.

The present invention solves the above-mentioned conventional problems, and oxygen is blown in a pretreatment furnace for hot metal or the like, which performs refining by blowing oxygen from the furnace bottom into a molten metal, a secondary refining furnace, a converter, and a continuous refining furnace. The purpose is to reduce the melting loss of refractory material in the blown tuyere and stabilize the operation.

[0012]

[Means for solving problems]

 The bottom-blown tuyere of the present invention is a bottom-blown tuyere for blowing molten metal by bottom-blowing of a reaction gas. The reaction gas discharge pipe is installed so as to penetrate in the longitudinal direction of the tuyere. On the tip side of the, the breathable refractory that circulates the cooling gas surrounds the periphery of the discharge pipe, and on the base end side of the tuyere, the non-breathable refractory surrounds the periphery of the discharge pipe and penetrates the non-breathable refractory. And a cooling gas supply pipe for the breathable refractory is provided, and a cooling gas reservoir is provided at the boundary between the breathable refractory and the non-breathable refractory. The supply pipe is characterized in that it is connected to the reservoir chamber.

[0013]

[Action]

 In such a bottom blowing tuyere, cooling gas is passed through the breathable refractory during blowing. This cooling gas is uniformly ejected from the tip surface of the tuyere. Therefore, mushrooms can be stably formed on the tip surface of the tuyere and its vicinity.

That is, in the tuyere according to the present invention, the cooling gas is ejected in a wide range, and a large non-contact space is created between the molten metal and the breathable refractory, thereby protecting the refractory.

Therefore, unlike the conventional method, the mushroom formation is not a unique requirement, and the operational know-how becomes very easy.

As a result, the refining reaction in the furnace is extremely stable, and the wear of the hearth also progresses on average, so that the total life of the refractory is extended.

[0017]

【Example】

 Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. FIG. 1 is a sectional view showing the structure of a tuyere according to an embodiment of the present invention. As shown in FIG. 1, the bottom 2 of the blowing furnace is provided with a hole 2 having an outer (lower) spread. A breathable refractory 3 is made into a truncated cone shape in accordance with the hole 2 of the bottom refractory, and a discharge pipe 5 for introducing oxygen gas is provided at the center, and a cooling gas for introducing cooling gas is provided outside the discharge pipe 5. A supply pipe 7 is provided. A cooling gas storage chamber 8 is provided at the bottom so that the cooling gas passes through the inside of the breathable refractory 3 on average. A gas box 9 is provided around the cooling gas storage chamber 8 in order to prevent the cooling gas from escaping to the outside of the furnace bottom and leaking out of the furnace. The back (lower part) of the gas box 9 is lined with a non-breathable refractory material (irregular refractory material) 10 to facilitate replacement of tuyere.

According to this tuyere, the cooling gas passes through the breathable refractory 3 and is ejected into the molten metal 11 in the blowing furnace, but from the entire surface of the breathable refractory 3 around the oxygen discharge pipe 5. As shown in FIG. 2, since the conventional double-tube type unstable mushroom 12 as shown in FIG. 2 is not formed, the oxygen discharge pipe 5 and the surrounding furnace bottom refractory are shown in FIG. Such uneven melting loss 13 does not occur.

Since the bottom blowing mechanism according to the present invention is integrally manufactured in advance, it can be easily exchanged hot without waiting for the cooling of the blowing furnace. It can be said that it is a bottom-blown tuyere that has the functions required for mushrooms from the beginning.

Experimental Example The following operation experiment was performed and compared with the conventional method. In order to match the experimental conditions as much as possible, a 50 kg MgO crucible was used for the bottom blowing furnace, and it was considered that there would be little change in the internal dimensions even after long-term operation.

A hole was made in the bottom of the crucible, and a bottom blown tuyere composed of a breathable refractory according to the present invention was incorporated. For comparison, we also conducted an operation experiment using a double-tube tuyere by the conventional method shown in Fig. 2.

Table 1 shows detailed experimental conditions and results.

[0023]

[Table 1]

[0024]

[Effect of the device]

 As is clear from the above experimental examples, the bottom blowing tuyere of the present invention can suppress the melting loss of the refractory material on the bottom of the furnace to a minimum, and the operation can be performed stably. Suitable for In addition, the stirring capacity of the bath is superior to that of conventional tuyeres, and it is possible to promote evenness in the furnace and efficiency of the reaction. In addition, the tuyere is easy to manufacture and replace. In addition, according to the present invention, uneven melting loss of the tuyere refractory is prevented, so that the life of the refractory is extended and the unit consumption of the refractory is significantly reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a bottom blown tuyere according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional example.

[Explanation of symbols]

 1 Furnace bottom refractory 3 Breathable refractory 8 Cooling gas reservoir 12 Mushroom

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumiaki Matsumoto 1-76 Horinouchi-cho, Minami-ku, Yokohama-shi, Kanagawa (72) Inventor Akira Kasahara 3-17-5 Hasune, Itabashi-ku, Tokyo (72) Inventor Satoshi Ogata Tokyo 4-18-20 Nakamurakita, Nerima-ku, Tokyo (72) Creator Hisao Kojima 4-5-9 Shiba, Minato-ku, Tokyo (72) Creator Tomio Watanabe 1-2-11 Harigaya, Urawa-shi, Saitama Prefecture

Claims (1)

[Claims for utility model registration] [Claim 1] In a bottom-blown tuyere for blowing molten metal by bottom blowing of reaction gas, the reaction gas discharge pipe is installed to penetrate in the longitudinal direction of the tuyere. , On the tip side of the tuyere, a breathable refractory that circulates the cooling gas surrounds the circumference of the discharge pipe, and on the proximal side of the tuyere, a non-breathable refractory surrounds the circumference of the discharge pipe, and A cooling gas supply pipe is provided to the breathable refractory through the refractory, and a cooling gas reservoir is provided at the boundary between the breathable refractory and the non-permeable refractory, and A bottom blown tuyere, wherein a cooling gas supply pipe is connected to the reservoir chamber.