JPH0421726B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a gutter structure for pre-refining hot metal, and particularly to a gutter structure for pre-refining hot metal having a built-in pipe for heat exchange.

(Prior Art) Hot metal tapped from a blast furnace is led to a moving container (such as a torpedo car) through an upwardly open gutter and sent to the next process.

In recent years, the demand for higher quality steel has increased, and in response to this, pretreatment of hot metal to remove harmful P, S, etc. has started to be carried out before blowing in a converter. . However, these pre-refining processes require the use of slag-forming agents tailored to the respective components to be removed, and the sludge must be removed each time after the completion of the treatment, resulting in an increase in the number of processing steps.

As a method to improve this, hot metal flows continuously.
A method has been proposed in which the above-mentioned preliminary refining is performed continuously in the blast furnace tap trough. However, the slag generated during smelting severely erodes the refractories, so in blast furnace tap troughs where spare refractories cannot be easily replaced, the lifespan of the refractories becomes a problem, and Preliminary refining did not go as planned. A means of protecting refractories would be desirable.

Here, as a method of protecting gutter refractories,
No. 58-33287 discloses a method of incorporating cooling piping within a refractory. However, whether water or air cooling is used, the used water or air is simply discharged to the outside, so there is a problem in that energy (water supply or air blowing power) required for protection is required.

On the other hand, after refractory construction, drying to remove moisture within the refractory is normally carried out by applying a burner flame or the like to the hot metal flow path surface, which also serves as preheating of the operating surface. Thermal efficiency is poor, for example,
53-24308, etc., so that heat can be easily transmitted to the inside, or, as in Utility Model Application No. 57-35353, a heat exchange tube is buried inside the refractory and preheated with a heat medium. Although it has been proposed, there have been problems such as defects in the refractory surface or the inability to heat the heat exchange tube to a sufficiently high temperature.

(Problems to be Solved by the Invention) Thus, an object of the present invention is to provide a gutter structure for pretreatment and refining of hot metal, which has a long service life by providing a refractory cooling means.

Furthermore, the object of the present invention is not only to provide a simple cooling means, but also to provide a gutter structure for pretreatment and refining of hot metal, which can preheat the refractory prior to use, and when the hot metal passes through, can serve both to cool the refractory and to inject refining gas. The goal is to provide the following.

(Means for solving the problem) In order to achieve such an objective, the present inventors
After various studies, it was discovered that the gas blowing means of the hot metal pretreatment device, which the applicant had previously proposed in Japanese Patent Application No. 60-245707, also had a cooling effect on some refractories, and further studies were conducted. As a result, the present invention was completed.

That is, the gist of the present invention is a gutter structure composed of a hot metal flow path surrounded by a refractory, a pipe is built inside the refractory for substantially heat exchange, and one end of the pipe is This is a gutter structure for pre-refining hot metal, characterized in that one end is opened on the outside of the gutter and the other end is opened into the hot metal flow path.

Here, "substantially in a heat exchange relationship" means that the tube is provided with one purpose of exchanging heat, and at least a portion thereof extends parallel to the hot metal flow path. .

Further, the "piping" may be a suitably shaped pipe buried in the refractory, or may be formed in advance by leaving a space in the shape of a pipe, and this may be used as the pipe. Although the former is superior in terms of strength, the latter is preferable in terms of heat exchange efficiency.

In this way, when the gutter is in operation (during blast furnace tapping), a gas injection pipe that opens into the hot metal from the side or bottom of the gutter is installed inside the gutter refractory, and the pipe is shaped like a serpentine pipe inside the refractory. , the refractory is cooled from inside by blown gas, and the hot metal temperature locally increases due to refining. In addition, during preheating (during drying) immediately after replacing the gutter refractories, the piping is heated by passing burner flame or appropriate exhaust gas instead of blown gas to raise the temperature from inside the refractories. At that time, the exhaust gas that heats the inside of the refractory and raises its temperature is released toward the inside of the gutter (hot metal flow path), so if a heat-insulating lid is placed on the open part at the top, the temperature on the working surface of the gutter will also rise. This greatly improves the efficiency of energy use required for preheating.

Therefore, according to another aspect of the present invention, a pipe is built into the gutter refractory for blast furnace tapping, and one end of the pipe is opened outside the gutter and the other end is opened into the hot metal flow path. However, when raising the temperature of the gutter refractories, high-temperature gas such as exhaust gas from a boiler burner etc. is passed through the piping, and on the other hand, when tapping iron where it is necessary to cool the gutter refractories, cooling gas is passed. This is a method for protecting gutter refractories for hot metal pre-smelting.

In addition, if one end opened in the hot metal flow path is configured with a porous nozzle, the blowing stirring gas can be stopped when the hot metal is stagnant other than during blast furnace tapping, and cooling of the stagnant hot metal can be prevented.

(Function) The attached drawing is a schematic perspective view showing a part of the gutter structure according to the present invention in cross section. A pipe 13 is buried inside the object 12 and is arranged in a substantially heat exchange relationship with the inside of the hot metal channel 10. In the illustrated example, this pipe 13 is buried while forming a flexible pipe 14. One end 15 of this pipe is opened at an appropriate position within the hot metal flow path to form a blowing nozzle, and the other end 16 is opened to the outside and connected to an external supply source (not shown) as appropriate. There is.

There are many possible concrete shapes for the pipe 13 buried in the heat exchange relationship, but one end is open in the hot metal flow path and constitutes a blowing nozzle, and the pipe 13 is buried in a heat exchange relationship. All are within the scope of the present invention as long as they are within the scope of the present invention.

The so-called slag line is a site where the gutter refractories are subject to significant wear and tear, and therefore it is preferable that the cooling piping be arranged in such a way as to particularly well cool the vicinity of the slag line.

Note that the blown gas may be appropriately boiler exhaust gas for heating refractories, and the stirring gas may be an inert gas such as Ar gas for refining. Alternatively, a gas containing oxygen may be blown in as the oxidizing gas, but in this case care must be taken to avoid a rise in temperature due to heat generation.

(Effects of the Invention) As described above, by providing the gutter structure provided with heating and cooling means according to the present invention, the following benefits can be obtained.

(1) The temperature of the refractory can be raised in advance, and the time required to raise the temperature can be shortened.

(2) As an example of a modification, by making the nozzle at one end of the corrugated pipe a porous nozzle, a kind of heat retention effect can be utilized, and the refractory only needs to be cooled during hot metal pretreatment, and cooling is sufficient only when necessary. Therefore, the required amount of cooling gas is small.

(3) Since the hot metal is preheated while passing through the pipe, the temperature of the gas for stirring the hot metal becomes high, so the amount of hot metal stirring is reduced, and the amount of stirring gas can be increased accordingly.

(4) When gutter refractories are composed of monolithic refractories,
Drying of the refractory immediately after manufacture can be promoted by appropriately blowing high-temperature gas into the piping system.

[Brief explanation of drawings]

The accompanying drawing is a schematic perspective view, partially in section, of a gutter structure according to the invention. 10: Hot metal flow path, 11: Gutter structure, 12: Refractory, 13: Piping.

Claims (1)

[Claims] 1 A gutter structure consisting of a hot metal flow path surrounded by a refractory, with piping built inside the refractory for substantially heat exchange, one end of which is outside the gutter, and the other end is connected to the hot metal. A gutter structure for pre-refining hot metal, characterized by opening into a flow path.