KR101676117B1 - Method for control of furnace - Google Patents

Abstract

The present invention relates to a converter maintenance method, and a converter maintenance method according to the present invention includes a floor separation step of separating a floor including a nozzle from a converter; And a bottom attaching step of attaching the bottom portion, which has been replaced or positioned, to the converter after the bottom separating step.

Description

Method for control of furnace [0002]

The present invention relates to a converter maintenance method, and more particularly, to a converter maintenance method capable of extending the life of a refractory.

Generally, a steel-making converter process is a process of removing impurities from molten iron produced in a furnace and refining them into pure molten steel. The converter used in this process can be said to be a container having a bag shape in which a high-temperature melt of 1600 캜 to 1750 캜 is accommodated.

That is, as shown in FIG. 1, the converter 10 has a bottom portion 12 and a side wall portion 11 extending to the top of the bottom portion. The floor portion and the side wall portion are provided with a refractory material such as a permanent field (not shown) and a built-in fence provided inside the permanent field. The bottom portion 12 is provided with a bottom flap 12b on the bottom flap 12a And the sidewall part 11 is provided with a sidewall part 11b inside the sidewall part 11a.

Particularly, a plurality of nozzles 20 are fixed to the bottom portion 12 of the converter 10, and the nozzle serves to homogenize the temperature and the components by stirring the molten steel by supplying an inert gas. The flow rate of the inert gas supplied to the nozzle 20 is increased in order to downsize the phosphorus (P) component in the charcoal line at the beginning of the transferring.

During the decarburization refining, a certain gas is injected from the lance hole (not shown) in the upper portion of the converter 10 toward the nozzle 20.

However, in such a decarburization refining process, the refractory including the sidewall portion 11b and the bottom portion 11b of the converter can be damaged by the repetitive process. That is, wear (damage) due to abrasion due to physical friction with molten steel, chemical and thermal erosion, and sudden temperature change may occur.

If damage to the refractory occurs, a serious accident that the molten steel in the converter 10 flows out to the outside may occur. Therefore, a maintenance process for periodically replacing the converter refractory is required.

However, a minimum of four to five days is required to maintain the refractory of the converter, and since the converter is shut down during that time, it takes a great deal of time and money to construct additional converters.

Accordingly, there is a need for a refractory management and replacement method capable of minimizing damage to the converter refractory and extending the life of the refractory.

Korean Unexamined Patent Publication No. 2002-0001388 (published on Mar. 01, 2002)

An object of the present invention is to increase the efficiency of a steel making process to increase the productivity of a product and to reduce the cost consumed in the process, thereby reducing the manufacturing cost of the product.

Specifically, the object of the present invention is to minimize the damage of the converter refractory to reduce the downtime of the converter.

Another object of the present invention is to provide a method for extending the service life of refractories during maintenance of a converter refractory.

In order to achieve the above-mentioned object, the present invention provides the following transfer maintenance method.

A method for maintenance of a converter according to a preferred embodiment of the present invention includes: a bottom separating step of separating a bottom portion of a refractory containing a nozzle from a converter; And a bottom attaching step of attaching the bottom, which has been replaced or positioned, to the converter after the bottom separating step, wherein the bottom attaching step is performed before or after the bottom attaching step, Further comprising a gas adjusting step of changing a position of a gas supplying part for injecting the gas into the reactor, wherein the bottom attaching step includes a step of, when the bottom part is rotated at a predetermined angle in the circumferential direction before the bottom part is separated from the converter, And the bottom attaching step rotates the bottom part within a range of more than 0 degrees and less than 180 degrees so that a region where the nozzle and the refractory of the bottom part contact each other is changed.

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Further, the method may further include a maintenance step performed after the bottom separating step and replacing or repairing the opening of the bottom part.

In addition, in the maintenance step, the nozzle fixed to the bottom portion is separated from the bottom portion to be replaced or repaired. After the replacement or repair, the nozzle is disposed at the same position as the bottom separating step in the bottom portion .

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According to the converter maintenance method according to the preferred embodiment of the present invention, the productivity of the product can be increased and the manufacturing cost can be reduced.

In particular, the local damage of the converter refractory can be suppressed by a simple method without increasing the maintenance cost of the converter.

Therefore, there is an effect that the life of the converter can be prevented from being reduced due to the local damage of the converter refractory.

Fig. 1 schematically shows the internal structure of a converter.
2 is a plan view showing the converter bottom.
Fig. 3 shows the flow simulation results of the converter internal molten steel.
Fig. 4 is a plan view showing the floor of the converter after the bottom mounting step is performed in the state of Fig. 2. Fig.
FIG. 5 is a schematic view showing a converter maintenance method according to a preferred embodiment of the present invention. FIG.

In order to facilitate an understanding of the description of the embodiments of the present invention, elements denoted by the same reference numerals in the accompanying drawings are the same element, and among the constituent elements that perform the same function in each embodiment, Respectively.

Further, in order to clarify the gist of the present invention, a description of elements and techniques well known in the prior art will be omitted, and the present invention will be described in detail with reference to the accompanying drawings.

It is to be understood, however, that the spirit and scope of the present invention are not limited to the embodiments shown, but may be suggested by those skilled in the art in other forms, additions, or alternatives, .

The first nozzle 20a, the second nozzle 20b, the third nozzle 20c, the fourth nozzle 20d and the fifth nozzle 20e mentioned below together with the attached drawings are provided in the nozzle 20, And for the sake of convenience in explanation, it is to be noted that the nozzles 20 are merely designated by the number of the nozzles 20 and are not intended to limit the nozzles inside the converters.

In the steelmaking process using the converter 10 shown in FIG. 1, decarburization refining operation is performed using a low noise nozzle 20 and an upturned lance (not shown) fixed to the bottom portion 12 of the converter 10. The converter 10 may include a sidewall portion 11 and a bottom portion 12. The sidewall portion and the bottom portion are each provided with a refractory made of a material having a high heat resistance.

The refractory is classified into a permanent field (not shown), a built-in fringe provided inside the permanent field, and the like. The side wall portion 11b and the bottom portion 12b of the side wall portion 11, And a bottom flap 12b provided on the iron foil 12a.

In the decarburization refining operation using a converter, the rate of decarburization reaction rate is determined by the amount of the gas (in particular, oxygen) supplied through the lance lance (not shown). Accordingly, the amount of the inert gas supplied to the nozzle 20 and the amount of gas supplied through the lancing lance (not shown) vary depending on the initial stage, the middle stage, and the late stage of the tanning.

As the decarburization refining operation of the converter proceeds, the molten steel inside the converter is gradually oxidized. The progress of the oxidation of molten steel gradually increases the concentration of iron oxide (FeO) contained in the slag, which causes a decrease in the refining realization rate of the molten steel. In addition, the temperature inside the converter is further increased by the heat of oxidation of molten steel.

Excessive temperature rise and oxidation reactions inside these converters also gradually impair the refractory inside the converter 10. [ At this time, the refractory of the converter 10 is not uniformly damaged as a whole but is concentrated on the periphery of the fixed nozzle 20 through the bottom portion 12a of the converter 10 as shown in Fig. 1, .

In general, a plurality of nozzles may be spaced apart from each other at regular intervals in the bottom portion 12a of the converter 10. In the present invention, a total of five nozzles are provided, and nozzles are provided at positions as shown in FIG. 2 and FIG. 3.

3 shows the molten steel flow in the case where the first nozzle 20a, the second nozzle 20b, the third nozzle 20c, the fourth nozzle 20d and the fifth nozzle 20e are provided at the bottom of the converter, respectively Simulation results are shown, which shows that the flow of molten steel around the nozzles is concentrated. Thus, the refractory around each of the nozzles accelerates the damage or erosion.

In addition, the gas injected from the uptake lance (not shown) as described above tends to further accelerate the damage or erosion of the refractory around the nozzles.

Therefore, in a preferred embodiment of the present invention, a converter maintenance method as shown in Fig. 5 is provided for suppressing the local damage of the refractory as described above, wherein the converter maintenance method according to the present invention includes A bottom separating step (S100) of separating the bottom part from the converter, and a bottom mounting step (S200) of mounting the bottom part to the converter after the bottom separating step.

The converter 10 shown in FIG. 1 is provided to detach a bottom portion 12 including a nozzle 20 for maintenance. Therefore, in the bottom separating step S100 described above, the bottom portion 12 including the nozzle 20 can be separated from the converter 10. [

Thereafter, the operator can completely replace the bottom flue 12b or fill in the blank space depending on the damage condition of the refractory. The maintenance step S300 may be performed after the bottom separating step S100, but the maintenance step may be omitted at the operator's discretion.

This is because the converter maintenance method according to the preferred embodiment of the present invention can suppress the local damage of the refractory even without replacing or filling the refractory inside the converter 10, By the rotation of the bottom 12 separated from the bottom 12.

2 and 4 show a top plan view of the converter 10. FIG. 2 shows a state of the bottom portion before the bottom separating step S100 is performed. FIG. 4 shows a state of the bottom portion separating step S100 And the bottom mounting step (S200) for mounting the bottom part to the electric vehicle again is performed.

Referring to FIG. 2, first, second, third, fourth, and fifth nozzles 20a, 20b, 20c, 20d, and 20e are installed at the bottom of the converter before the bottom separation step S100 is performed Able to know. At this time, as described above, the gas injected from the lance lance (not shown) is concentrated in the first gas supply part 30a, the second gas supply part 30b and the third gas supply part 30c, which are peripheral areas of the nozzles Is being sprayed.

Accordingly, intense damage to the surrounding regions of the nozzles 20a, 20b, 20c, 20d, and 20e including the first, second, and third gas supply portions 30a, 30b, and 30c occurs.

Thus, in the bottom mounting step S200, the floor 12 is first rotated in the circumferential direction at a predetermined angle before the floor separated from the converter is coupled again to the converter. Preferably, the angle of rotation of the bottom 12 is in the range of greater than 0 degrees but less than 180 degrees.

4, when the bottom part 12 is rotated 180 degrees, the positions of the nozzles are reversed. Therefore, before the bottom separation step S100 is performed, the area where the refractories are in contact with the nozzles So that it is possible to prevent the occurrence of the overlap as much as possible.

The areas of the first, second, and third gas supply units 30a, 30b, and 30c are also different from the state prior to the bottom separating step S100, so that damage to the refractory material can be prevented from being limited to a local area It is effective.

Therefore, even after the maintenance step (S300) for replacing or repairing the refractory is performed, the nozzles need to be disposed at the same position as the bottom separating step.

This is to prevent overlapping of the positions of the nozzles when the bottom part 12 of the converter is coupled to the converter again in the bottom mounting step S200 performed after the maintenance step, S200) is performed, the position of the nozzles is changed from before the bottom separation step S100 is performed.

According to this, by merely rotating the turnover bottom 12 without adding any additional equipment or cost, it is possible to prevent the local damage of the converter refractory by changing the area where the refractories come in contact with the nozzles do.

Preferably, the converter maintenance method according to the present invention is performed before or after the bottom mounting step (S200), and includes a gas adjusting step of changing a position of a gas supplying part for injecting an inert gas onto the nozzle at an upper portion of the converter The gas supply unit may be the first, second, and third gas supply units 30a, 30b, and 30c described above, and the number of the gas supply units may vary depending on the operator and the work environment .

The gas supply unit in the gas adjustment step S400 may be an upright lance (not shown). At this stage, the position of the upright lance (not shown) may be changed without overlapping with the nozzle 20 at this stage.

According to the gas adjusting step (S400), the gas injection region can be adjusted more quickly to suppress the local erosion of the refractory. That is, when this step is not performed, the gas injection region that follows the peripheral region of the nozzle 20, which is gradually changed by the flow of the molten steel, can be arranged at a different position more quickly. However, this is a matter that can be appropriately selected and applied depending on the operator and the work environment, and is not limited by the present invention.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It will be apparent to those of ordinary skill in the art.

10: converter 11:
12: bottom portion 20: nozzle

Claims (6)

A bottom separating step of separating the bottom part including the nozzle and equipped with the refractory from the converter; And a bottom attaching step of attaching the bottom portion, which has been replaced or positioned, to the converter after the bottom separating step,
Further comprising: a gas adjusting step performed before or after the bottom mounting step to change a position of a gas supplying part that injects an inert gas around the nozzle at an upper portion of the electric converter,
Wherein the bottom mounting step causes the bottom portion to be coupled to the converter while being rotated at a predetermined angle in a circumferential direction at a position before the bottom portion is separated from the converter,
Wherein the bottom mounting step rotates the bottom part within a range of more than 0 degrees and less than 180 degrees so that a region where the nozzle and the refractory of the bottom part contact each other is changed.
delete The method according to claim 1,
A maintenance step carried out after the bottom separating step and replacing or repairing the opening of the bottom part;
Further comprising the steps of:
The method of claim 3,
In the maintenance step,
Wherein the nozzles fixed to the bottom portion are detached from the bottom portion to be replaced or repaired, and after the replacement or repair, the nozzles are disposed at the same positions as the bottom separating step at the bottom portion. Way.


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