JPH11229012A - Structure for arranging stave in shaft furnace type metallurgical furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the durability of a stave in a shaft furnace type metallurgical furnace, to restrain the heat loss through the stave as little as possible and further, to reduce the equipment cost needed to the stave, etc. SOLUTION: This arranging structure of the staves, with which the long service life of the stave in the whole furnace and the energy saving with the restraint of heat conduction through the stave and the cost reduction on the equipment and the operation can be achieve by optimally arranging the staves in each zone according to the difference of the surrounding condition, is found out under the attension to the point, in which the large difference is developed in the surrounding at the inside of the furnace wall in the furnace height direction. In the furnace height direction, in the upper part and middle part zone (A) of the furnace with the small heat load, the cast iron-made staves are arranged, and in the lower part zone (B) of the furnace, with the large heat load at lower than the above zone (A), the copper or copper alloy-made staves are arranged, and in the lowermost zone (C) in the furnace at lower than the above zone (B), the cast iron-made staves or the copper or copper alloy-made staves are arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a stave arrangement in a shaft type metallurgical furnace such as a blast furnace.

[0002]

2. Description of the Related Art A furnace wall structure of a blast furnace has a structure in which a stave (cooling stave) having an internal cooling mechanism is provided inside a steel shell, and a furnace-side refractory is held inside the stave. Normally, when the blast furnace is operated for a certain period, the refractory inside the furnace falls off the stave due to breakage or the like, and the stave is often directly exposed to the inside of the furnace. Therefore,
The stave must be able to withstand the heat load inside the furnace even after the refractory inside the furnace falls off.

Conventionally, cast iron staves have been widely used as blast furnace staves, and among them, those having a structure in which a cooling pipe is cast with cast iron are generally used. But,
Such a cast iron stave has a low cooling capacity due to the low thermal conductivity of the cast iron. For this reason, in the high heat load region of the blast furnace, high thermal stress occurs in the stave body and cracks are easily generated,
This crack propagates to the cooling pipe and easily causes a water leakage accident.

In order to prevent such breakage of the cooling pipe, it is common to make the cooling pipe and the casting non-fused. However, in this structure, the cooling ability of the stave is further reduced. Further, in order to compensate for such a decrease in the cooling capacity, for example, the cooling capacity is increased by increasing the number of cooling pipes, and the stave body corresponding to erosion is extended by duplicating the stave body. Attempts have been made to increase the cooling capacity by combining and integrating cast iron staves with copper or copper alloy staves, but these measures have been taken to increase the amount of cooling water, increase the weight of staves, staves and furnace walls. Since the structure is complicated, the cost of manufacturing the stave is increased, and the heat loss due to the cooling water is increased, so that the energy loss is increased.

[0005]

In particular, in recent years, staves have been required to have higher durability in accordance with the prolonged life of blast furnaces and the severe operating conditions caused by the injection of a large amount of pulverized coal. From the viewpoint of energy saving, it is also important to minimize the heat loss of the furnace due to the stave. Therefore, an object of the present invention is to maintain the durability of a stave of a shaft furnace type metallurgical furnace, minimize the heat loss of the furnace due to the stave, and reduce the equipment cost required for the stave and the like.

[0006]

SUMMARY OF THE INVENTION Research on conventional staves has always focused on improving the structure of the stave from the viewpoint of increasing the cooling capacity and durability of the stave itself. On the other hand, the present inventors have found that the environment inside the furnace wall in a shaft furnace type metallurgical furnace such as a blast furnace, for example, heat load, presence or absence of molten slag, degree of furnace wall deposits, etc. Focusing on the differences, we conducted a detailed study on the suitability of staves according to these environmental differences. As a result, by arranging the optimal staves in each area according to the environment inside the furnace wall, it is possible to extend the life of the staves of the entire furnace and save energy by suppressing heat removal from the staves, In addition, they have found that it is possible to achieve lower costs in terms of equipment and operation.

The present invention has been made based on such findings, and the features thereof are as follows. [1] In the furnace height direction, cast iron staves are placed in the upper and middle furnace areas (A) where the heat load is small, and copper or copper alloy is placed in the lower furnace area (B) where the heat load is lower. A stave arrangement structure for a shaft type metallurgical furnace, wherein a stave made of steel is arranged, and a stave made of cast iron or a copper or copper alloy is arranged in a lowermost region (C) of the furnace below the stave.

[2] In the stave arrangement structure of the above [1], a furnace lower region in which a copper or copper alloy stave is arranged.
(B) The stave arrangement structure of a shaft furnace type metallurgical furnace, wherein (B) includes at least a main slag generation start area and a slag existence area in the furnace during a normal operation.

[3] In the stave arrangement structure of the above [1] or [2], a bosh section, a cutting section, and a shaft section are provided in order from a furnace lower side in a furnace height direction, and a tuyere is provided at a furnace lower end side. In a shaft furnace type metallurgical furnace, a furnace lower region (B) in which a copper or copper alloy stave is arranged is an upper region of a bosh portion, an entire region of a cut portion and a lower region of a shaft portion, and is a cast iron stave or copper or A stave arrangement structure of a shaft type metallurgical furnace, wherein a lowermost region (C) of a furnace in which a copper alloy stave is arranged is a lower region of a bosh section above the tuyere.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted detailed studies on the environment inside a furnace wall in a shaft furnace type metallurgical furnace such as a blast furnace and the suitability required for a stave under this environment. Table 1 summarizes the results.

[0011]

[Table 1]

That is, the following points have been clarified regarding the in-furnace environment of each region (part) in the furnace height direction of the shaft furnace type metallurgical furnace and the suitability of the stave applied thereto. (1) Furnace upper region (part in the case of a general blast furnace: upper part of the shaft portion): Since this region has a relatively small heat load and no molten slag, erosion of the stave hardly occurs. In addition, if a stove with a large cooling capacity is placed in this area, the amount of heat removed from the furnace at the top of the furnace will increase, resulting in a large energy loss and a reduction in the production amount, as well as the zinc and alkalis in the exhaust gas. Adhering to the furnace wall at the top of the furnace, which prevents the charge from descending smoothly, resulting in unstable furnace conditions.

Further, in this region, when the raw material charging surface is lowered, the charged raw material may directly hit the stave. Therefore, it is necessary to use a stave having high rigidity. Therefore, it is preferable to select the stave applied to this region from the viewpoint of suppressing heat removal and preventing damage and wear due to collision of the charged raw material rather than the viewpoint of preventing melting damage.

(2) Middle furnace region (region in the case of a general blast furnace: middle of the shaft portion): Since this region also has a relatively small heat load and no molten slag, stave erosion hardly occurs. Also, when a stave having a large cooling capacity is arranged in this region, the same problem as in the above-described furnace upper region may occur. Therefore, it is preferable to select a stave to be applied to this region from the viewpoint of suppressing heat removal rather than the viewpoint of preventing erosion.

(3) Lower part of furnace (area in case of general blast furnace: lower part of shaft part, cutting part, upper part of bosh part): This area is the starting area of molten slag generation (lower part of shaft part)
And a high heat load region including a region where the molten slag is always present (the cut portion, the upper part of the bosh section), and a stave applied to this region is intended to prevent erosion and suppress heat removal as much as possible. It is preferable to select from

(4) Furnace lowermost region (part of general blast furnace: lower part of bosh section): This region is originally a high heat load region where molten slag exists, In this case, the slag adhering to the furnace inner wall (stave) solidifies to form a solidified slag layer, and the solidified slag layer is difficult to peel off due to the angle of repose of the furnace wall. Is relatively small. Therefore, in the case of a furnace having the general structure as described above, it is preferable that the stave applied to this region is selected from the viewpoint of suppressing heat removal from the viewpoint of preventing erosion. On the other hand, when the solidified slag layer attached to the stave is easily peeled off due to the structure of the furnace, it is preferable to select the slag layer from the viewpoint of preventing erosion and suppressing heat removal as much as possible.

Further, as a result of studying the suitability of the staves corresponding to each region in the furnace height direction as described above, and studying the types and characteristics of the staves to be used, the cast iron staves have a low cooling capacity. It is suitable as a stave to be applied to a region mainly focused on suppression of heat removal, while a copper or copper alloy stave is suitable for a region mainly focused on prevention of erosion. Is a highly effective stave that not only keeps the temperature inside the main body low because of its high thermal conductivity, but also prolongs its life in the high heat load region and suppresses heat removal from the furnace for the following reasons: It turns out. That is, even if the furnace or refractory inside the furnace falls off from the stave body in the high heat load region of the furnace, the copper or copper alloy stave solidifies as soon as the molten slag comes into contact with the stave surface due to its high cooling ability. A hardly exfoliated solidified slag layer is formed. This solidified slag layer has very low thermal conductivity,
The stave is protected from the high heat load of the furnace, and heat removal from the furnace by the stave is appropriately suppressed.

Therefore, in the present invention, based on the above-described examination results, the heat load is relatively small, and the heat removal from the furnace needs to be suppressed as much as possible. Cast iron staves are placed in the upper and middle areas (A) where there is a need to prevent damage and wear of the furnace, and copper or copper alloy is used in the lower furnace areas (B) below which the heat load is higher. A stave is arranged, and a cast iron stave or a copper or copper alloy stave is arranged below the furnace lowermost region (C). FIG. 1 is a vertical sectional view of a shaft furnace type metallurgical furnace.
(A), the lower furnace region (B) and the lowermost furnace region (C) are indicated by (A) to (C). In the drawing, 1 is a stave, 2 is a refractory inside the furnace fixed to the cooling operation surface of the stave body, 3 is a tuyere, and 4 is a steel shell.

According to such a stave arrangement structure of the present invention, by disposing a cast iron stave in the furnace upper / middle region (A), heat removal from the furnace is appropriately suppressed. Since this region has a relatively small heat load and no molten slag, erosion hardly occurs even with a cast iron stave. By disposing a cast iron stave in this area to suppress heat removal from the furnace, a large energy loss does not occur and the production volume does not decrease. Does not hinder the charge from descending smoothly. Also, in the furnace upper region, when the raw material charging surface is lowered, the charged raw material may directly hit the stave, but since the rigid cast iron stave is arranged, damage or wear of the stave occurs. Less.

Further, a stove made of copper or a copper alloy having a high cooling capacity is disposed in the lower furnace region (B) where the heat load is large and the molten slag starts to be generated and where the molten slag exists. Can be appropriately prevented. Also,
Copper or copper alloy staves have a hard-to-peel solidified slag layer on the surface in the high heat load area where molten slag exists. And the durability thereof is maintained, and the heat removal from the furnace by the stave is appropriately suppressed.

Further, by disposing a cast iron stave in the lowermost region (C) of the furnace, heat removal from the furnace can be appropriately suppressed. This region is originally a high heat load region in which molten slag exists, but in the case of a general blast furnace or the like, the slag adhered to the stave and solidified forms a solidified slag layer, and the solidified slag layer forms a solidified slag layer. The actual thermal load acting on the stave is relatively small, since it is difficult to peel off due to the angle of repose of the wall. Therefore, in the case of a furnace having a general structure,
Even if a cast iron stave is arranged, there is no erosion. When the solidified slag layer adhering to the stave is easily peeled off due to the structure of the furnace, a stave made of copper or a copper alloy is arranged to prevent the stave from being melted.

Here, the lower furnace area (B) where the copper or copper alloy stave is arranged is an area including at least a main molten slag generation start area and a molten slag existing area in the furnace during a steady operation. Is preferred. Also, as shown in FIG. 1, in a normal shaft furnace type metallurgical furnace having a bosh section, a cut section and a shaft section in order from the furnace lower side in the furnace height direction, and a tuyere at the furnace lower end side, copper or copper is used. The furnace lower region (B) in which the copper alloy stave is disposed is an upper region of the bosh portion, the entire region of the cut portion, and a lower region of the shaft portion, and the furnace lower region in which the cast iron stave or the copper or copper alloy stave is disposed. The lower region (C) is a lower region of the morning glory above the tuyere.

As described above, in the stave arrangement according to the present invention, even if the furnace load is relatively small and the molten slag does not exist in the furnace upper and middle regions (A) or the high heat load region, the furnace wall deposits (solidified slag) In the lowermost part of the furnace (C), where heat load is not a problem due to the layer), a low-cost and low-cost cast iron stave is arranged to reduce equipment costs and suppress heat removal from the furnace. The durability of the stave is maintained while achieving the above, and in the upper and middle regions of the furnace, the suppression of heat extraction suppresses the generation of furnace wall deposits, thereby enabling a smooth descent of the furnace interior charge. In addition, the stave can be prevented from being damaged or worn due to the collision of the charged raw materials. On the other hand, in the lower furnace area (B), which is a high heat load area in which molten slag exists, disposing a stave made of copper or a copper alloy having a high cooling capacity appropriately prevents erosion of the stave, etc. The solidified slag layer generated on the surface of the stave by quenching the slag protects the stave and suppresses the heat removal from the furnace, so that the stave durability is appropriately controlled while suppressing the heat removal from the furnace. Will be maintained.

As described above, according to the present invention, the use of a cast iron stave and a copper or copper alloy stave in accordance with the environment inside the furnace wall makes it possible to appropriately maintain the durability of the stave of the entire furnace, Heat extraction from inside can be suppressed as much as possible. For this reason, the life of the furnace can be prolonged and the energy cost can be reduced rationally, and the cooling cost and erosion resistance of individual staves do not need to be excessively increased, thus reducing equipment costs. Can be.

Examples of the copper or copper alloy stave include a stave obtained by machining a rolled material or the like and a cast copper stave (including, for example, a type in which a cooling pipe is cast with cast copper). In the present invention, any type of stave may be used, and the structure, material, manufacturing method and the like are not limited. However, the cast copper stave has a lower thermal conductivity than the stave obtained by machining, but the manufacturing cost is small,
In addition, it is more preferable to use a cast copper stave, since it can be freely manufactured according to the furnace profile.

As a copper stave, for example, JIS
CuC1, CuC2, CuC specified in H5100
3 etc. are used, and as a copper alloy stave,
For example, low alloy copper such as chrome zircon copper and beryllium copper is used. Further, the stave arrangement structure of the present invention can also be applied to a shaft furnace type metallurgical furnace other than a blast furnace (for example, a scrap melting furnace).

It should be noted that the cast iron stave is most suitable as the stave to be applied to the furnace upper / middle region (A) for the above-described reason. If there is a stave or a stove combining cast iron with another material, and a stave having approximately the same cooling capacity as a cast iron stave, this is a cast iron stave in the furnace upper / middle region (A). May be used in place of part or all of. Similarly, a cooling box having substantially the same cooling capacity as a cast iron stave may be used instead of part or all of the cast iron stave in the furnace upper / middle region (A).

[0028]

According to the present invention described above, it is possible to effectively maintain the durability of the stave of the entire furnace in the shaft furnace type metallurgical furnace, and to suppress the heat removal from the furnace by the stave as much as possible. . For this reason, the life of the furnace can be prolonged and the energy cost can be reduced rationally. In addition, since there is no need to excessively increase the cooling capacity and erosion resistance of individual staves, equipment costs are also reduced. be able to.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a shaft type metallurgical furnace to which a stave arrangement structure of the present invention is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Stave, 2 ... furnace inside refractory, 3 ... Tuyere, 4 ... Steel, (A) ... upper / middle area, (B) ... lower area, (C) ...
Furnace bottom area

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsuneo Araki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Masahiro Matsuura 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan (72) Inventor: Shuo Terada, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan In-tube (72) Inventor: Makoto Ushigo 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Inside Steel Pipe Co., Ltd.

Claims (3)

[Claims] In the furnace height direction, a cast iron stave is arranged in the furnace upper / middle region (A) where the heat load is small, and copper or copper is placed in the furnace lower region (B) below the heat load where the heat load is large. A stove arrangement structure for a shaft type metallurgical furnace, wherein a copper alloy stave is arranged, and a cast iron stave or a copper or copper alloy stave is arranged in a furnace lowermost region (C) below the stave. 2. A furnace lower region (B) in which a copper or copper alloy stave is disposed includes at least a main molten slag generation start region and a molten slag existing region in the furnace during a normal operation. Item 2. A stave arrangement structure of the shaft furnace type metallurgical furnace according to Item 1. 3. A copper or copper alloy stave is arranged in a shaft type metallurgical furnace having a bosh section, a cut section, and a shaft section in order from the furnace lower side in the furnace height direction and a tuyere at the furnace lower end side. The lower furnace region (B) is the upper region of the bosh portion, the entire region of the cut portion and the lower region of the shaft portion, and the lowermost region (C) of the furnace where a cast iron stave or a copper or copper alloy stave is arranged. And a lower area of the bosh section above the tuyere.
The stave arrangement structure of the shaft furnace type metallurgical furnace according to 1.