JP2001108377A - Cooling method of refractory and refractory surface deposit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of a refractory due to the contact of the refractory with water and to cool the refractory and a deposit quickly on the occasion of cooling forcibly the refractory of a refining furnace and a molten metal holding vessel and the deposit on the surface of the refractory. SOLUTION: In the method for cooling forcibly a refractory 2 and a deposit on the surface of the refractory, dry ice 1 is blown against a place to be cooled, for the purpose of cooling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forcibly cooling a high-temperature refractory or a high-temperature deposit on a surface of the refractory, and more particularly to a method for preventing deterioration of the refractory due to contact of the refractory with water. The present invention relates to a cooling method capable of rapidly cooling refractories and deposits.

[0002]

2. Description of the Related Art In a refining furnace or a molten metal holding vessel constructed of a refractory inside, such as an electric furnace for melting molten metal and a ladle for holding the molten metal, the wear of the refractory is not uniform. In order to reduce the unit consumption of refractories and to save resources, repairing only severely damaged parts often occurs. In this case, it is necessary to cool the smelting furnace and the molten metal holding vessel for repair work.Since cooling or slow cooling requires a slower cooling time and a longer repair time and is not efficient, water is directly sprayed on the refractory. Then forced cooling was done.
However, in the case of forced cooling by spraying water, it is necessary to replace the refractory in the sound part because the refractory that has absorbed the water gets wet with the surrounding healthy refractory and deteriorates. The results were inconsistent from the reduction of resources and resource saving.

[0003] In the case of full repair, the refining furnace and the molten metal holding vessel are similarly forcibly cooled in order to improve the operation rate and the turnover rate. Permanent bricks on the back side get wet with water and must be replaced due to deterioration.

[0004] In addition, during use or repair, high-temperature deposits such as ingots and slag adhering to the inner wall of a smelting furnace or a molten metal holding vessel may need to be cooled to remove water. When water is directly sprayed on the attached matter, there is a problem that the surrounding refractory is wet and the refractory deteriorates.

Therefore, a method of forcibly cooling by spraying an ultrafine mist on a refractory as disclosed in, for example, Japanese Patent Laid-Open No. 5-208148 has been used. FIG. 2 shows an example of an ultra-fine mist injection nozzle disclosed in Japanese Patent Application Laid-Open No. 5-208148. As shown in FIG. 2, the ultra-fine mist injection nozzle includes a pair of flow path portions 53A and 53B that are inclined and separated from each other at the tip of an adapter connecting portion 52 of a nozzle body 51, and These flow path portions 53A,
The nozzles 54A and 54B are attached to the tip of the nozzle 53B at an angle so as to be close to each other, and air and water separately sent from the adapter 55 are mixed inside the nozzles 54A and 54B, 54A, 54
B is jetted as two fluids of water and air, and the jetted two fluids collide with each other to make the particle diameter ultra-fine.

[0006] By using an ultra-fine spray nozzle to cool, the degree of wetting with water is greatly reduced as compared with a method of cooling by directly spraying water. Although the refractory surface of the sound part is also small, the refractory is deteriorated by being wet with water.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for forcibly cooling a high-temperature refractory and a deposit on the surface of the refractory when the refractory is wetted with water. It is an object of the present invention to provide a forced cooling method capable of preventing deterioration of a refractory caused by contact with the refractory and rapidly cooling the refractory and the attached matter.

[0008]

According to the present invention, there is provided a method for cooling refractories and deposits on refractory surfaces, the method comprising forcibly cooling refractories and deposits on refractory surfaces. It is characterized by spraying and cooling.

In the present invention, dry ice is sprayed on the refractory or the deposits on the surface of the refractory, and the refractory and the deposits on the surface of the refractory are cooled by utilizing the extremely low temperature characteristic of dry ice. The sprayed dry ice scatters and cools the surrounding refractory, but the dry ice does not wet the refractory because it sublimes into the atmosphere. Can be prevented.

In the present invention, since the dry ice is sprayed, the dry ice is broken by the impact force at the time of collision with the surface of the refractory or the attached matter and adheres to the object to be cooled. The cooling effect increases as compared with the case. Further, since the dry ice is sprayed, there is no need to level the object to be cooled.

Further, when dry ice is sprayed on the deposit on the surface of the refractory, the deposit is rapidly cooled and shrinks rapidly, so that the detachment of the deposit can be promoted.
Further, the impact force at the time of spraying may accelerate the removal of the attached matter.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing an example of an embodiment of the present invention.

As shown in FIG. 1, a blast machine 3 for spraying dry ice has a hopper 4 and a feeder 5 mounted thereon, and can be moved by wheels 10 provided at the bottom thereof. A pelletizer 9 is installed at a position distant from the blast machine 3. The dry ice pellets 1 produced by the pelletizer 9 using liquid carbon dioxide as a raw material pass through the flexible pipe 11 and pass through the hopper 4.
Then, it is cut out from the hopper 4 through the chute 12 while the cutout amount is controlled by the feeder 5.

Compressed air which has been pressurized by a compressor 7 and whose moisture has been removed by a dryer 8 is fed into the feeder 5 through flexible pipes 13 and 14, and the dry ice pellet 1 cut out by the feeder 5
Is sent to the blast nozzle 6 by the compressed air through the flexible pipe 15, and from the blast nozzle 6, the refractory 2 of the refining furnace or the molten metal holding container, or the deposit (not shown) on the surface of the refractory 2 Spouted toward.

At this time, the distance L from the tip of the blast nozzle 6 to the surface of the object to be cooled such as the refractory 2 is 5 to 100 cm.
The dry ice pellet 1 is sprayed while maintaining the degree. As the speed at which the dry ice pellet 1 collides with the object to be cooled increases, the cooling ability of the dry ice pellet 1 improves. Therefore, it is preferable that the speed at the time of collision be equal to or higher than the speed of sound. The shape of the dry ice pellet 1 may be any shape such as a sphere, a cylinder, a rectangular parallelepiped, or the like. The size of the dry ice pellet 1 depends on the passage holes of the feeder 5 and the blast nozzle 6, but the speed at the time of collision is maintained at a speed higher than the sound speed, and the time until sublimation is secured to improve the cooling efficiency. In order to let
It preferably has a volume equivalent to a sphere having a diameter of 1 to 10 mm.

By cooling the refractory and the deposits on the surface of the refractory in this way, the refractory can be prevented from getting wet with water.
In addition, the target portion can be quickly cooled.
When repairing only severely worn parts, even if the surrounding refractories are cooled, they do not deteriorate because they do not get wet with water, even if they are cooled. Greatly contributed to. In addition, even in the case of the entire repair, the refining furnace and the molten metal holding container can be quickly cooled without deteriorating the permanent brick because it does not get wet with water.

In the above description, the dry ice pellets 1 manufactured by the pelletizer 9 are supplied to the blasting machine 1. However, the dry ice pellets 1 manufactured by other equipment without using the pelletizer 9 are kept in a heat insulating container. The blast machine 1 may be stored in a storage tank and supplied to the blast machine 1 from a heat retaining container when used.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment using a cooling device having the structure shown in FIG. 1 will be described. Table 1 shows the equipment specifications of the compressor used, and Table 2 shows the equipment specifications of the blast machine.

[0019]

[Table 1]

[0020]

[Table 2]

First, dry ice pellets are vertically sprayed on a steel plate installed on a weighing machine using this cooling device,
The impact force was measured. The test conditions were as follows: air pressure at the time of spraying was 18 kg / cm ² , and air amount was 350 m ³ / h.
r, the amount of dry ice pellets sprayed was 200 kg /
hr and the distance from the blast nozzle tip to the steel plate is 5
cm, 10 cm, and 30 cm. The temperature of the dry ice pellet is -80C. Table 3 shows the measurement results.

[0022]

[Table 3]

As shown in Table 3, the impact force was constant at 6.5 kg, and the impact value was 0.08 kg / cm ² when the distance from the tip of the blast nozzle to the steel plate was 30 cm. The dry ice pellet was destroyed by the impact force when it hit the steel sheet under any conditions, and adhered to the steel sheet in a crushed state. From these results, the increase in the contact area and the increase in the cooling capacity were evident as compared with the case where the dry ice pellet was simply placed on top.

Next, the refractory at the bottom of a 50-ton electric furnace was cooled using the cooling apparatus. The cooling conditions were as follows: air pressure at the time of spraying was 9 kg / cm ² , and air amount was 400 m ³ / h.
r, the dry ice pellet spray amount was 280 kg /
hr, a total of 280 kg of dry ice pellets was sprayed toward the furnace bottom refractory surface while controlling the distance from the tip of the blast nozzle to the spray surface to 10 to 30 cm. The temperature of the dry ice pellet is -80C,
Deposits such as slag were present on the furnace bottom refractory surface.

The timing of the start of the spraying of the dry ice pellets is the same as in the case of cooling using a conventional ultra-fine mist injection nozzle. Later.

In the conventional cooling method using an ultra-fine mist injection nozzle, the amount of water is suppressed to such an extent that no water pools are formed on the surface of the furnace bottom refractory or the surface of the furnace bottom deposit in order to prevent the refractory from getting wet with water. It took about 6 hours to reduce the atmosphere temperature in the furnace to 40 ° C. because it is necessary to reduce the atmosphere temperature in the furnace to 40 ° C. in about 1 hour by implementing the present invention. Was completed. In addition, when an ultra-fine mist injection nozzle was used in spite of spraying by the above method, a refractory wet with water was generated. However, in the cooling method of the present invention, the refractory did not wet with water at all.

[0027]

According to the present invention, it is possible to efficiently and quickly cool the refractory and the deposits on the refractory surface while preventing the refractory from deteriorating due to contact with water.
As a result, it is possible to greatly promote the reduction of the refractory basic unit and the resource saving.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an embodiment of the present invention.

FIG. 2 is a view showing an example of a conventional ultra-fine mist injection nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dry ice pellet 2 Refractory 3 Blast machine 4 Hopper 5 Feeder 6 Blast nozzle 7 Compressor 8 Dryer 9 Pelletizer

Claims (1)

[Claims] 1. A method for forcibly cooling a refractory and a deposit on the surface of a refractory, wherein the cooling is performed by spraying dry ice on a portion to be cooled. .