KR20010059578A - Division cooling system for using in the lower part of the blast furnace - Google Patents

Abstract

PURPOSE: A cooling system is provided which is related with arrangement and control of cooling pipe at the hearth bottom considering the heat flow curve in the refractory material layer of the hearth part so that the erosion state of the refractory material layer of the hearth bottom is partially controlled. CONSTITUTION: In a system for cooling refractory materials installed at the hearth bottom (5) of the hearth part of a blast furnace in which hot metal and slag are stored, the cooling system is characterized in that the position of a multi-path cooling circuit is divided into the surrounding part and the center part in the pipe installed on the hearth bottom, wherein a short multi-path cooling water pipe circuit in which a length of the cooling pipe is short is installed at the surrounding part where heat load from the hearth bottom is most greatly exhibited so as to improve cooling capability while a long multi-path cooling water pipe circuit (14) having cooling capability is arranged at the center part so as to secure smooth passage of hot metal according to the maintenance of erosion shape of refractory materials to a certain degree.

Description

Division cooling system for using in the lower part of the blast furnace}

The present invention relates to a cooling system for controlling the phenomenon that the refractory is installed in the hearth bottom of the refractory installed in the bottom of the blast furnace molten iron and slag storage inevitably over the years of operation. .

In general, the blast furnace industry produces molten iron and slag by charging charged materials (iron ore + coke) from the top of the blast furnace into the furnace and blowing hot hot air through the air vent installed at the bottom of the furnace to cause reduction and melting in the furnace. Done. The melt thus produced is stored in the bottom part through the core coke layer 2 filled in the bottom part 1, and is discharged out of the furnace during the opening of the blast furnace outlet 3.

Since the bottom part 1 is a place where molten iron and slag of 1500 ° C. or more are stored and discharged, heat flow is generated by the thermal equilibrium principle from the inner side, which is the hot side in contact with the molten iron, to the outer side of the low temperature side where the shell is installed. The refractory body 8 is installed on the inner side of the bottom shell and the cooling device is installed on the outer side.

The bottom refractory structure usually includes an amorphous refractory (stamping material) that connects the steel shell and the normal softening from the outer shell to the inner side of the bottom wall of the furnace (4), a high thermal conductivity shaped lead, and a corrosion resistant shaped lead (ceramic cup). Etc.) In the case of the furnace 5, an erosion-resistant shaped lead, a high thermal conductivity form carbon + graphite, an amorphous refractory material, and a bottom plate shell 6 are provided from the upper side to the lower side in contact with the molten iron.

The cooling device in the bottom part is equipped with a spray method (9) in which the cooling water flows down to the shell surface in the case of the bottom wall part, or a stave cooling device for flowing the cooling water into the pipe, while the bottom part has a surface part. The pipe cooling method (7) is adopted to pass through the cooling medium by installing pipes at regular intervals under the steel bar.

Conventional bottom surface pipe cooling device (7) is installed in the cooling pipe linearly at regular intervals throughout the bottom surface (5) linear pipe cooling to collectively supply the cooling water in one direction and to discharge the cooling water in the opposite direction collectively The method 11 is adopted and used (refer FIG. 1).

The size of the bottom surface heat load of the furnace bottom portion 1 is closely related to the erosion of the bottom surface refractory 8, as well as the melt temperature and the amount of melt accumulation present inside the bottom refractory. The refractory erosion of the bottom part is closely related to the state of securing fluidity of the core coke layer (2) which exists with the hot melt in the bottom part, the depth of the exit port (3) for discharging the melt, and the erosion state of the bottom face refractory. have.

In particular, the refractory 8 erosion state of the bottom surface has the greatest influence on the refractory erosion of the bottom side wall portion 4 which is closely related to the blast furnace life extension. That is, when the refractory 8 of the bottom surface is uniformly eroded in a predetermined amount, a smooth refractory surface is formed, and when the molten iron flows through the bottom surface during the blast furnace operation, the flow resistance decreases, and a large amount of the molten iron is the bottom surface (5). Since it flows out through), it is possible to reduce the amount of molten iron flow to the side wall portion 4 side of the furnace, thereby preventing the erosion of the side wall portion refractory.

However, when the refractory is locally eroded from the bottom surface to form an uneven refractory surface, the molten iron flow resistance increases at the bottom surface refractory surface. In this case, since the amount of molten iron flows on the surface of the bottom surface and the amount of molten iron flows on the surface of the bottom side wall portion, the amount of refractory erosion of the bottom portion of the bottom portion increases.

The refractory erosion shape of the bottom surface has a deep relationship with the cooling system installed at the bottom of the bottom surface, and the existing bottom surface cooling system has the following problems as a straight pipe cooling system (11).

First, since the cooling water flows in one direction and flows out in the opposite direction, on the water supply 12 side where the cooling water flows, the cooling capacity is increased by the low temperature cooling water, and the refractory erosion of the bottom surface is suppressed, but the cooling water flows. This is because the cooling water heated up while flowing out from the water supply side cools the furnace floor refractory 8 on the outgoing drainage 13 side.

That is, the cooling capacity is lowered, which makes it difficult to suppress refractory erosion. In this case, the refractory surface of the bottom surface exhibits a wear shape that is inclined from the cooling water supply side to the draining side, and serves to shorten the blast furnace life by providing a factor of increasing the erosion of the bottom side of the bottom side of the cooling water supply side. 4)

Second, when one part of the bottom surface is eroded locally and the other part is in a condition where the ridge occurs due to the growth of deposits, increase the flow rate of cooling water to enhance the cooling capacity of the bottom surface erosion part. Erosion control is possible, but at raised areas, the deposits grow more and more causing rugged bottom surface wear.

This uneven refractory surface of the bottom surface increases the molten iron flow resistance on the bottom surface, thereby providing a factor that activates sidewall refractory erosion because a large amount of molten iron flow is generated around the bottom side wall portion (4).

Third, the place where local erosion of refractories occurs most severely at the bottom of the blast furnace is around the exit port (3). In the blast furnace, the vortex phenomena is actively generated during the flow of melts accumulated in the bottom of the furnace when the melt is discharged, so that the erosion of the refractory is more active. There is a situation that can be progressed.

In particular, refractory erosion rapidly develops around the exit when the bottom surface refractory wear shape is elevated by the formation of an adhesion layer at the center of the bottom surface. To solve this problem, there is a need for a means of locally increasing the cooling capacity around the ship or lowering the cooling capacity of the central portion of the bottom surface to prevent the formation of deposits on the refractory surface.

However, in the case of the conventional straight tube planar cooling method 10, it is almost impossible to partially improve the cooling capacity around the ship or lower the cooling capacity of the center partly.

In other words, the erosion of the furnace sidewall portion refractory which directly affects the blast furnace life is greatly influenced by the furnace surface refractory erosion state.

The present invention has been made to solve the conventional problems as described above, the cooling pipe arrangement in the bottom surface considering the heat flow curve in the bottom refractory layer to partially control the erosion state of the bottom surface refractory and The purpose is to provide a cooling system related to control.

According to the present invention, in order to achieve the above object, the system for cooling the refractory is installed on the bottom surface of the bottom of the bottom portion for storing molten iron and slag of the blast furnace is the position of the multi-refractive cooling circuit for the pipe installed on the bottom surface It is characterized by separating the peripheral portion and the central portion.

1 is a view showing a structure of a general blast furnace bottom part.

2 is a view showing the heat flow in the blast furnace bottom part.

Figure 3 (a) and (b) is a view showing the refractory erosion of the blast furnace bottom portion, (a) is a bowl refractory erosion, (b) is a mushroom refractory erosion.

4 (a) and (b) schematically show the cooling system of the blast furnace bottom section according to the prior art embodiment.

5 is a view showing a cooling system of a short multi-refractive refrigeration pipe circuit installed in the blast furnace furnace section in accordance with an embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

1: bottom part

2: core coke

3: exit

4: Noser side wall part

5: bottom surface

7: cooling pipe

15: cooling pipe circuit

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

First, a cooling piping circuit was separately installed at the periphery and the center of the bottom surface so as to partially control the cooling conditions of the bottom surface.

In the case of the periphery where the heat load is greatest on the bottom surface, a short multi-path cooling water pipe circuit (15) having a shorter length of the cooling pipe was installed to improve cooling capacity.

In particular, the installation density of the cooling pipe circuit was increased around the exit, which has the greatest refractory erosion effect.

However, in the case of the central part, a long multi-path cooling water pipe circuit 14 having low cooling capacity was disposed to secure a smooth molten metal path according to maintaining a refractory erosion shape to some extent.

That is, the cooling pipe circuit which greatly increased the cooling pipe length was provided.

The second improvement was the installation of two stages of bottom cooling pipe placement.

In other words, the cooling pipe circuit was installed in the refractory of the upper part of the bottom plate of the bottom plate, which is a position where the heat load is concentrated during the operation of the blast furnace. Similarly, a two-stage batch cooling circuit system 18 is provided in which a cooling pipe is installed below the bottom plate of the bottom plate.

Third, the improvement of the periphery short multi-refractive cooling pipe circuit (15) in the upper water supply bottom drain cooling circuit system for cooling water supply and drainage position to ensure that the cooling water is supplied to the heat load is larger, and that the heat load is drained to the smaller side ( 19) was installed.

That is, in the cooling pipe circuit, the coolant water supply side was positioned above the upper platen part 6, and the drainage side was disposed below the lower platen part (see Fig. 6).

Therefore, the most desirable erosion shape of the furnace refractory is a bowl-type wear shape in which the center surface of the bottom surface is worn out smoothly and the periphery of the bottom surface is worn down while the bottom surface is smoothly worn. (See Fig. 3a).

In the present invention, by distributing the cooling pipe circuit of the bottom surface in each unit area of the bottom surface, in the case of the peripheral portion 17 where the short cooling pipe circuit is installed at a high density, the cooling capacity can be greatly enhanced.

This increases the flow rate of the cooling water in the cooling pipe circuit installed in the site for the local temperature rise of the bottom surface of the furnace surface, thereby making it possible to control the peripheral erosion in a short time.

In addition, in the case of the central part 16, since a long cooling pipe circuit can be arranged to always maintain a lower cooling capacity than the peripheral part, erosion of the bottom surface is always led to the central part to maintain the bowl-shaped bottom part erosion shape.

Since the cooling pipe circuit disposed at the periphery is installed at a close distance to the hot face 20 on the upper side of the bottom face, when the temperature of the bottom face 17 rises, the cooling pipe circuit 15 is placed upward. By enhancing the cooling capacity, the elevated temperature distribution of the peripheral refractory can be stabilized in a short time.

In addition, when the peripheral cooling capacity is maintained so large that the ridge phenomenon occurs due to the growth of deposits in the peripheral portion, the cooling capacity is changed from the conventional straight pipe cooling method 10 by lowering the flow rate of the peripheral cooling pipe circuit 15. It is possible to shorten the response time, so that it is possible to maintain a stable state of the refractory erosion at all times. (See Fig. 5)

In the case of the center of the bottom surface 16, a long multi-refractive refrigeration pipe circuit 14 was installed, and the cooling pipe installation position was installed in the lower part of the bottom plate of the bottom of the bottom of the furnace just like the existing blast furnace, so as to be far from the high temperature section 20 of the top of the bottom surface. It was.

Since the long cooling pipe circuit has a long distance from the passage of the cooling water through the discharge, the cooling water temperature rises easily from the increase in the heat exchange time between the cooling water and the surrounding refractory pipe, leading to a decrease in the cooling capacity of the center.

In addition, the cooling pipe circuit 14 installed far from the upper portion of the upper surface of the furnace surface 14 is to supply the same amount of cooling water per unit time in accordance with the increase in the refractory thickness to be cooled to the upper portion of the upper surface of the furnace surface It has a lower cooling capacity than that contributes to maintaining a certain amount of refractory erosion in the center of the bottom surface (see Fig. 5).

In addition, at the periphery, the short multi-refractive cooling pipe circuit installation 15 minimizes the temperature rise of the cooling water by shortening the distance that the cooling water passes through the pipe, and also introduces the upper water supply and the lower drainage system in the cooling circuit. 19) discharged the cooling water whose temperature rises while passing through the cooling circuit to the lower side of the bottom plate 6, so that the temperature difference between all parts which are in horizontal contact with the cooling circuit is kept to a minimum.

Therefore, in order to induce the bowl-shaped wear pattern in the erosion shape of the bottom part during the normal operation, it is possible to partially control the cooling state of the bottom surface by improving the bottom surface cooling pipe arrangement method.

The above is summarized as follows.

That is, according to an embodiment of the present invention, the bottom of the blast furnace erosion by using a cooling system in which the installation level of the multi-refraction cooling circuit is arranged in two stages by separating the installation level of the multi-refractive cooling circuit into the periphery and the center of the furnace bottom. To prevent.

Therefore, according to the present invention, when the refractory erosion of the bottom portion is a refractory erosion of mushroom-shaped (Fig. 3b) in which the center of the bottom surface is raised and the bottom surface and the bottom side wall portion are eroded (Fig. It was possible to secure the molten iron flow passage in the bottom of the bottom surface by inducing the erosion of the deposit attached at the center from the decrease in the cooling capacity through the decrease in the flow rate of the cooling water.

In addition, it is possible to prevent the edge erosion and to form a deposit of a suitable size on the surface of the bottom surface and the hot face 20 by strengthening the cooling capacity by increasing the cooling water supply amount in the peripheral cooling pipe circuit 15 of the peripheral portion. It was possible to prevent the shortening of blast furnace life due to damage (see Table 1).

In the state in which the central part 16 of the bottom part is kept eroded to some extent, the abnormal growth of the peripheral part by the active growth of the attachment of the peripheral part causes the non-ideal bowl-shaped bottom edge and erosion phenomenon that lowers the volume of the bottom part. There is a case.

When such a situation occurs, it is possible to maintain an ideal bowl shape by effectively dissolving the deposits grown in the periphery from the decrease in cooling capacity due to the decrease in the amount of cooling water of the cooling circuit 15 installed in the periphery. B of FIG. 3)

In addition, when refractory erosion on the bottom surface occurs locally in a narrow range, it is easy to localize the refractory erosion amount by partially adjusting the cooling water supply amount of the cooling pipe circuit installed in the erosion area, so that it is always stable in high productivity. It was possible to perform.

The foregoing is merely illustrative of the preferred embodiments of the present invention and those skilled in the art to which the present invention pertains may make modifications and changes to the present invention without departing from the spirit and gist of the invention as set forth in the appended claims. It should be recognized.

Claims (1)

What is claimed is: 1. A system for cooling refractory materials installed on the bottom surface of a bottom portion of a blast furnace for storing molten iron and slag, Cooling system, characterized in that for separating the location of the multi-refraction cooling circuit to the periphery and the center of the pipe installed on the bottom surface.