JPH09263814A - Double tube lance for pretreating molten iron - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily observe the reduced thickness condition and the hole-opening caused by the wearing of an inner tube and an inner tube holder part and, at the same time, to enable the exchange of the inner tube, in a double tube lance concentrically arranged with an outer tube and the inner tube. SOLUTION: The tip part fitting a rubber ring 33 for sealing in an annular groove 31 arranged at the inner holding part 12 is connected by fitting into the inlet side of the inner tube 17. Pressure of an inert gas for carrying flux, blown into the inner tube 17 through an inner tube holder part 12, is acted on the rubber ring 33 for sealing through plural slits 32 and sealed by bringing the rubber ring 33 into close contact with the inner peripheral surface of the inner tube 17. At the time of releasing the gas pressure, since the inner tube holder part 12 can freely be attachable/detachable to the inner tube 17, the inner tube holder part 12 is taken out and the wearing condition can simply be checked.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an outer tube and an inner tube which are used for removing powdery or granular hot metal pretreatment agent (flux) into the hot metal in a reaction vessel to remove impurity elements in the hot metal. The present invention relates to a double pipe lance concentrically provided for hot metal pretreatment.

[0002]

2. Description of the Related Art Si, P, etc. are contained in hot metal produced in a blast furnace.
Although a large amount of impurity elements such as S are contained, these impurity elements have a great influence on the refining efficiency and the quality of the steel in the next steelmaking process such as a converter. Therefore, in general, prior to the steelmaking process, a hot metal pretreatment is performed to remove the impurity elements. In order to perform hot metal pretreatment, the lance for hot metal pretreatment is immersed in the hot metal contained in the reaction vessel such as a mixing pig car or hot metal ladle, and a pretreatment agent (flux) is blown into the hot metal together with the carrier gas from this lance. During the process in which bubbles containing the processing agent powder and granules float in the hot metal, a gas-liquid reaction is performed to achieve dephosphorization, desulfurization, etc.

[0003] For example, in the dephosphorization treatment of molten pig iron,
The dephosphorization treatment is carried out by blowing dephosphorization flux consisting mainly of quick lime, iron ore and mill scale into the hot metal together with a carrier gas using a hot metal ladle or the like as a reaction vessel. Iron ore and mill scale blown into the hot metal decompose in the hot metal to become an oxygen source, and the dephosphorization reaction proceeds. An inert gas has been conventionally used to convey and blow the dephosphorization flux. This is because when oxygen gas is used, CaO, iron ore, scale, etc. in the dephosphorization flux usually show 0.5%.
This is because about 1.0 carbon is mixed and there is a risk that oxidizable substances such as carbon will react with oxygen gas and cause troubles such as combustion and explosion.

As described above, even when only the inert gas and the dephosphorization flux are used, a certain degree of dephosphorization rate can be expected, but since the reaction efficiency is low, a large amount of the dephosphorization flux can be used to increase the dephosphorization rate. It is uneconomical because it requires Therefore, it has been attempted to use oxygen gas as an oxygen source instead of iron ore and mill scale to reduce the temperature drop during decomposition of iron ore and mill scale and improve the dephosphorization efficiency. As a means for blowing the dephosphorization flux and oxygen gas into the hot metal, oxygen gas is blown using one lance and the desulfurization flux is blown together with the inert gas using another lance. It is known to use a lance or a single lance having a double tube structure for blowing.

In the conventional lance having a double pipe structure, an inner pipe and an outer pipe that are concentrically provided are integrally manufactured, that is, a so-called integral body. Oxygen gas is blown into the hot metal separately from the outer pipe, and inert gas carrying dephosphorization flux is blown into the hot metal separately from the inner pipe. In the lance having such a double pipe structure, the oxygen gas blown from the outer pipe and the flux blown together with the inert gas from the inner pipe are not sufficiently mixed in the hot metal, so that the oxygen gas is sufficient for the dephosphorization reaction of the hot metal. There was a problem that it did not contribute.

In order to solve this problem, Japanese Patent Publication No. 62-660
No. 8 discloses mixing of a double pipe structure with an outer pipe connected to an oxygen gas pipe and an inner pipe connected to an inert gas pipe for carrying flux and having a part of the pipe wall made of porous sintered metal. Department,
A double tube lance is disclosed having an extension of the inner tube and a blow-in portion immersed in the hot metal. With this double tube lance, the flux and the oxygen gas can be blown into the hot metal in a state of being completely mixed in the lance through the porous sintered metal, so that the dephosphorization efficiency can be improved. However, there is no change in that the outer tube and the inner tube have a double tube structure in which they are integrated.

[0007]

In the conventional lance having the double pipe structure, since the outer pipe and the inner pipe are manufactured as a single body, the dephosphorization flux carried by the inert gas does not flow inside. Even if the part that collides with the pipe is worn, it is difficult to understand the wear condition. Also, if the inner pipe is worn away and a broken hole is generated or the tip of the lance is melted, the complete double pipe lance including the sound outer pipe must be replaced, which is uneconomical. It was

The present invention solves the problems of the prior art and makes it possible to easily inspect the wear condition of the inner pipe and the inner pipe holder by making the inner pipe and the inner pipe holder removable from the outer pipe. At the same time, it is an object of the present invention to provide a double pipe lance for hot metal pretreatment in which a damaged or melted one can be replaced and a sound one can be reused.

[0009]

According to the present invention for achieving the above object, an outer tube and an inner tube are concentrically provided with a lance holder portion connected to an inlet side of the outer tube, and an inlet side of the inner tube is provided. In a double pipe lance for hot metal pretreatment having an inner pipe holder connected to the outer pipe connecting part, an outer pipe connecting part formed to bend outside the lance axis with a curvature at the inlet side of the lance holder part, and the outer pipe connecting part. Of the inner pipe holder part, which is formed straight on the lance axis of the part and has a connecting flange at the inlet end, and a connecting flange corresponding to the connecting flange provided at the tip of the lance holder part. An outer pipe and an inner pipe that are detachably connected and supported, a connecting flange that is provided midway on the inlet side of the inner pipe holder portion, and a tip end outer peripheral surface of the inner pipe holder portion that communicates with the inner peripheral surface. Multiple slits A drilled ring-shaped groove and a sealing rubber ring mounted in the ring-shaped groove are provided, and the inner pipe holder portion is inserted through the inner pipe holder supporting pipe seat through the lance holder portion. The outer peripheral surface of the tip end, in which the rubber ring for sealing is attached to the ring-shaped groove provided in the inner pipe holder part, is fitted into the inlet side of the inner pipe supported by the tip of the lance holder part through the connection flange. On the other hand, while connecting, connect the connection flange provided in the middle of the inlet side of the inner pipe holder portion to the connection flange provided at the inlet end of the inner pipe holder supporting pipe seat, and through the inner pipe holder portion. The pressure of the inert gas for flux transport blown into the inner pipe is applied to the sealing rubber ring attached to the ring-shaped groove provided in the inner pipe holder through the plurality of slits communicating with the inner peripheral surface. Inflate outward A double pipe lance for pretreatment of hot metal, characterized in that the sealing rubber ring is closely attached to the inner peripheral surface of the inner pipe to seal the connecting portion between the inner pipe holder portion and the inner pipe. is there.

The present invention according to claim 2 is characterized in that the distance pieces are arranged at intervals in the lengthwise direction of the outer peripheral surface of the inner pipe and the inner pipe holder part. Double pipe lance for hot metal pretreatment.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. As shown in FIG. 5, a tilting frame 5 is provided on a bearing 3 provided at the tip of the lance traveling carriage 1 via a shaft 4 so as to be tiltable by using a tilting cylinder 24, and the lance lifting carriage 2 is mounted on the tilting frame 5. Is placed so that it can be raised and lowered. A double pipe lance 6 for pretreatment of hot metal is mounted on the lance lift truck 2.
Is a guide roller 9 arranged at the tip of the tilting frame 5.
It is supported movably. The double tube lance 6 is shown in FIG.
As shown in FIG. 3, a lance holder portion 8 is provided so as to be connected to the inlet side of the outer pipe 7.
It is attached to the lance lift truck 2 using.

As shown in FIG. 3, the double pipe lance 6 is formed with an outer pipe connecting portion 11 on the inlet side of the lance holder portion 8 so as to be bent outside the lance axis A with a curvature. An inner pipe holder supporting pipe seat 23 is formed straight on the lance axis A of the pipe connecting portion 11. A connecting flange 13 is provided at the inlet end of the outer pipe connecting portion 11, and an oxygen flexible pipe 14 is connected to the connecting flange 13. Further, at the inlet end of the inner pipe holder supporting pipe seat 23,
A connection flange 15 is provided. A connection flange 25 is provided at the tip of the lance holder portion 8.
As shown in FIG. 1, first, a connecting flange 26 provided midway on the inlet side of the inner pipe 17 is abutted with a packing 28, and then the connecting flange 26 is fitted with a packing 28 to the inlet end of the outer pipe 7. Butt the connection flange 27 provided on the. And three of the connection flanges 25, 26, 27 are detachably connected at the same time using the bolt 29 and the nut 30, whereby the outer pipe 7 and the inner pipe 17 are integrally supported at the tip of the lance holder portion 8. To be done.

As shown in FIG. 2, a ring-shaped groove 31 is provided on the outer peripheral surface of the tip portion of the inner pipe holder portion 12, and a plurality of slits 32 communicating with the inner peripheral surface are formed in the ring-shaped groove 31. is there. Then, the rubber ring 33 for sealing is placed in the ring-shaped groove 31.
Is attached to the bottom surface of the ring-shaped groove 31 in an airtight manner, and the outside is free. The inner pipe holder portion 12 is inserted via the inside of the lance holder portion 8 via the inner pipe holder supporting pipe seat 23, and the sealing rubber ring 33 is attached to the ring-shaped groove 31 provided in the inner pipe holder portion 12. The outer peripheral surface of the tip end portion is connected by being fitted into the inlet side of the inner pipe 17 supported by the tip end of the lance holder portion 8 via the connection flange 25. The inner pipe 17 has a connection flange 26 provided midway on the inlet side,
Since it is fixed to the connection flange 25 provided at the tip of the lance holder portion 8, there is no concern that the inner pipe 17 will fall out.

On the other hand, the connecting flange 18 provided in the middle of the inlet side of the inner pipe holder portion 12 is connected to the connecting flange 15 provided at the inlet end of the inner pipe holder supporting pipe seat 23 by using a bolt, and the inner pipe holder is connected. Support part 12. A connection flange 19 is provided at the inlet end of the inner pipe holder portion 12.
A flexible tube 16 for flux is connected to 19. In the length direction of the outer peripheral surfaces of the inner pipe holder portion 12 and the inner pipe 17, the ring-shaped distance piece 20 extends outward.
, Which are arranged at intervals, serve as a guide at the time of insertion and support the set position so as not to come off the center. Further, in the portion where the outer pipe 7 is immersed in the hot metal, in order to prevent melting damage, an irregular refractory material 22
Is lined.

When carrying out a pretreatment such as dephosphorization of the hot metal contained in a hot metal tank which is a reaction container (not shown), the lance traveling carriage 1 travels, approaches the reaction container, and operates the tilting cylinder 24. At the same time, the lance lifting carriage 2 is operated to direct the double pipe lance 6 into the hot metal in the reaction vessel. Then, oxygen gas is supplied from the flexible tube for oxygen 14, oxygen gas is blown out from the outer tube 7 via the lance holder portion 8, and argon gas for carrying the dephosphorization flux from the flexible tube for flux 16 is transferred to the inner tube holder. The double pipe lance 6 is immersed in and blown into the hot metal in the hot metal mixer while being blown out from the inner pipe 17 via the portion 12, to dephosphorize the hot metal.

Due to the pressure of the argon gas that conveys the dephosphorization flux to the inner pipe 17 via the inner pipe holder portion 12, the sealing rubber ring 33 attached to the ring-shaped groove 31 provided in the inner pipe holder portion 12, Swells outward through the plurality of slits 32. Therefore, the sealing rubber ring 33 is pressed against the inner peripheral surface of the inner pipe 17, the connection portion between the inner pipe holder portion 12 and the inner pipe 17 can be reliably sealed, and the oxygen gas and the dephosphorization flux are safely transported. Argon gas can be blown into the hot metal.

When the hot metal contained in a reaction vessel such as a hot metal wheel or a hot metal ladle is subjected to a pretreatment such as dephosphorization using the double pipe lance 6 having the above-described structure, the flux is transported together with the carrier gas. Since the inner pipe holder portion 12 and the inner pipe 17 are heavily worn, holes may be formed due to the thinning. If the operation is continued with holes in the inner pipe holder portion 12 and the inner pipe 17, the flux in the inner pipe 17 flows back into the outer pipe 7 through the opening caused by the damage and exists in the flux. There is a risk of oxidizable substances such as carbon exploding due to combustion. Therefore, after the pretreatment of the hot metal is completed, it is necessary to observe the inner pipe holder portion 12 and the inner pipe 17 forming the double pipe lance 6 to confirm the wear state and to carry out a safe operation.

In the present invention, after pulling up the double pipe lance 6 from the mixed piggy car, the lance traveling carriage 1 is moved to the retracted position to inspect the inner pipe holder portion 12 and the inner pipe 17. In order to check the state of thinning due to wear of the inner pipe holder portion 12, remove the bolts that connect the connection flange 15 and the connection flange 18 provided on the inner pipe holder supporting pipe seat 23 to the inlet of the inner pipe 17. This is done by pulling out the tip of the inner pipe holder portion 12 from the end. At this time, since the supply of the argon gas carrying the desulfurization flux is stopped, the sealing rubber ring 33 attached to the tip of the inner pipe holder portion 12 is shrunk, so that the inner pipe holder portion 12 can be easily removed. It can be pulled out and the inspection work is extremely easy.

Further, since the outer tube 7 and the inner tube 17 are not integrally formed and can be easily separated, when the inner tube 17 of the double tube lance 6 is observed, the tip of the lance holder portion 8 is The bolts 29 and the nuts 30 connecting the connection flanges 26, 27 provided at the inlet side ends of the inner pipe 17 and the outer pipe 7 to the connection flanges 25 provided in the section are removed. Then, by separating the outer pipe 7 and the inner pipe 17, it becomes possible to very easily check the state of metal thinning due to wear of the inner pipe 17. If the inner pipe holder part 12 or the inner pipe 17 is likely to be significantly thinned and has a hole, it is possible to replace the inner pipe holder part 12 and the inner pipe 17 independently and quickly to prevent an explosion etc. It becomes possible to prevent troubles in advance. For example, when the outer pipe 7 and the lance holder 8 are not damaged, the double pipe lance 6 can be reused as they are and replaced with new ones only for the damaged inner pipe holder 12 and inner pipe 17. Cost savings are achieved.

Although the present invention has been mainly described with respect to dephosphorization of hot metal, it can be applied to hot metal pretreatment other than dephosphorization.

[0021]

As described above, according to the present invention, the outer pipe and the inner pipe forming the double pipe lance are connected via the connecting flange, and the inner pipe holder portion and the inner pipe are connected to each other. Since the structure is airtightly connected through the rubber ring for sealing attached to the ring-shaped groove provided on the outer peripheral surface of the distal end of the section, these can be easily separated. For this reason,
After separating the outer pipe, the inner pipe, and the inner pipe holder part from the lance holder part, it is possible to easily confirm whether or not they can be reused by inspecting the thinning state due to wear of these parts. Then, the outer pipe, the inner pipe, or the inner pipe holder portion is separated, only the defective one can be replaced, and the sound one can be reused, so that the cost reduction of the double pipe lance can be achieved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a structure of a connecting portion constituting a double pipe lance of the present invention from a side surface.

FIG. 2 is a partial enlarged cross-sectional view showing a side surface of a connecting portion between an inner pipe holder portion and an inner pipe of a double pipe lance according to the present invention.

FIG. 3 is a side view showing a partial cross-section of the structure of the double pipe according to the present invention.

FIG. 4 is a side view showing the entire double pipe lance according to the present invention.

FIG. 5 is a side view showing a double pipe lance mounted on a tilting frame provided on a lance traveling vehicle according to the present invention.

[Explanation of symbols]

 1 Lance traveling carriage 2 Lance lifting carriage 3 Bearing 4 Shaft 5 Tilt frame 6 Double pipe lance 7 Outer pipe 8 Lance holder part 9 Guide roller 10 Connecting band 11 Outer pipe connection part 12 Inner pipe holder part 13 Connection flange 14 Flexible for oxygen Pipe 15 Connection flange 16 Flexible pipe for flux 17 Inner pipe 18 Connection flange 19 Connection flange 20 Distance piece 21 Short pipe 22 Irregular refractory 23 Inner pipe holder supporting pipe seat 24 Tilt cylinder 25 Connection flange 26 Connection flange 27 Connection flange 28 Packing 29 Bolt 30 Nut 31 Ring groove 32 Slit 33 Rubber ring for sealing

Claims (2)

[Claims] 1. An outer pipe and an inner pipe are concentrically provided with a lance holder connected to the inlet side of the outer pipe, and an inner pipe holder connected to the inlet side of the inner pipe. In a heavy pipe lance, an outer pipe connecting portion formed so as to be bent outside the lance axis with a curvature on the inlet side of the lance holder portion, and a straight pipe formed on the lance axis of the outer pipe connecting portion and connected to the inlet end. An inner pipe holder supporting pipe seat provided with a flange, and an outer pipe and an inner pipe which are separately and separably connected and supported by using a connection flange corresponding to the connection flange provided at the tip of the lance holder part, A connection flange provided in the middle of the inlet side of the inner pipe holder part, a ring-shaped groove provided on the outer peripheral surface of the tip end part of the inner pipe holder part and having a plurality of slits communicating with the inner peripheral surface, and the ring shape Installed in the groove A rubber ring for sealing is provided, and the inner pipe holder portion is inserted through the lance holder portion via the inner pipe holder supporting pipe seat, and the sealing rubber is inserted in the ring-shaped groove provided in the inner pipe holder portion. The outer peripheral surface of the tip portion with the ring attached is fitted into the inlet side of the inner pipe supported at the tip of the lance holder portion via a connection flange to be connected, while being provided midway on the inlet side of the inner pipe holder portion. The connecting flange is connected to the connecting flange provided at the inlet end of the inner pipe holder supporting pipe seat, and the pressure of the flux-conveying inert gas blown into the inner pipe through the inner pipe holder is The seal rubber ring attached to the ring-shaped groove provided in the inner pipe holder portion is caused to swell outward through a plurality of slits communicating with the inner peripheral surface, and the seal rubber ring is expanded to the inner periphery of the inner pipe. Close to the surface Double tube lance for hot metal pretreatment, characterized in that the connection portion of the inner tube holder portion and the inner tube is configured to be sealed by the. 2. The double piece for hot metal pretreatment according to claim 1, wherein distance pieces are arranged at intervals in a length direction of outer peripheral surfaces of the inner pipe and the inner pipe holder portion. Tube lance.