JP2737644B2 - Slow cooling stave cooler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slow cooling stove cooler which is mounted, for example, on a shaft of a blast furnace, in particular, a furnace opening.

[0002]

2. Description of the Related Art An example of a sectional view of a blast furnace is shown in FIG. 4, and the upper part of the blast furnace 1 is called a shaft part. It has a brickwork structure. However, in such a brickwork structure, the laminated bricks 2 begin to fall off in about 2 to 3 years after burning, and a step is formed at the fallout portion, and irregularities are generated in the circumferential direction in the furnace. The occurrence of the unevenness deteriorates the furnace port profile, makes the gas flow in the furnace unstable, and contributes to the deterioration of the furnace condition.

Therefore, as shown in FIG. 5, a refractory 3 is sprayed on the falling-off portion to eliminate irregularities on the inner wall of the furnace. Spraying is required, and the burden on work and cost is increased. In FIG. 5, reference numeral 4 denotes a furnace shell, and reference numeral 5 denotes a spray nozzle for the refractory 3.

Therefore, in recent years, a stove cooler 7 (see FIGS. 6 and 7) in which a brick 6 is held inside the furnace as described in JP-A-61-37904, and As described in -211 211 publication,
A stove cooler 9 (see FIG. 8) has been proposed in which a castable 8 of an insulating system is sprayed or hand-painted on the inner surface of the furnace.

[0005]

However, even with the stave cooler proposed in Japanese Patent Application Laid-Open No. 61-37904, the tip of the support metal 7a of the brick 6 is insufficiently cooled. Is oxidized by the high-temperature gas in the furnace, and the bricks 6 easily fall off in a short period of time and widely.
The same problem as in the case of the conventional brickwork structure occurs. In addition, the stave cooler itself has a cooling structure (having a heat transfer coefficient of 36).
(kcal / m ² h ° C), so if the embracing bricks fall off, the inner surface of the furnace will be supercooled and take part of the heat used for the reduction reaction from the inside of the furnace, causing the iron ore raw material to powder. I do. Then, due to this effect, the gas flow becomes uneven (one-sided flow),
This will lead to a worsening furnace situation.

The stave cooler proposed in Japanese Patent Application Laid-Open No. Hei 3-211 211 exhibits an effect in the initial state, but when the wear of the castables progresses, the stave cooler can be repaired in the conventional brick structure. Similarly, spray repair from inside the furnace is required. When this is repeated, the wear of the fixed studs 10 protruding from the stave cooler body progresses, and the life of the castable itself is shortened. In addition, since the surface of the remaining castable with heat history has significantly reduced strength, it is highly likely that the surface will be peeled off from the boundary even if the castable is sprayed on the surface, similar to the case of the conventional brickwork structure. Problems arise.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the conventional stove cooler, and particularly, when installed in a furnace opening which is a part of an upper portion of a shaft in a blast furnace, supercooling is not performed. It is an object of the present invention to provide a slow cooling stove cooler that can prevent the heat and extend the life of the heat insulator disposed on the inner surface of the furnace.

[0008]

In order to achieve the above-mentioned object, a slow cooling stove cooler of the present invention is a stave cooler for protecting a furnace shell from a heat load inside the furnace, and includes a stove cooler at least on a furnace inner surface. A stave cooler body having an inner peripheral recess formed by projecting two outer peripheries to the inside of the furnace, and a two-layer heat insulating material housed in the recess of the stave cooler main body, wherein the two-layer structure is provided. Insulation material is SiC type, high
Al ₂ high strength O ₃ system or the like, and the furnace inner layer made of insulation fired panel with high thermal conductivity, cordierite type, chamotte type and hollow Al ₂ O ₃ based low thermal conductivity, low strength insulation firing panel or pouring It is made of a stave cooler body side layer made of a material.

[0009]

[Effect] The following equation 1 is used as a parameter of thermal shock resistance.
There is a thermal shock coefficient K defined by

[0010]

K∝λ · σ _T / αE where λ: thermal conductivity σ _T : tensile strength α: linear expansion coefficient E: Young's modulus

In a refractory material, the coefficient of linear expansion α and the Young's modulus E do not change much even if the kind is changed. Therefore, in order to increase the thermal shock coefficient K, that is, to provide the thermal shock resistance, the thermal conductivity λ and the tensile strength The only way is to increase the σ _T.
However, increasing the thermal conductivity λ means that
On the other hand, slow cooling cannot be achieved. Also, the tensile strength σ
_As a means for increasing _T , it is effective to add a large amount of SiC, Al ₂ O ₃ or the like, but at this time, the thermal conductivity λ also increases, so that slow cooling cannot be achieved.

Therefore, the slow cooling stove cooler of the present invention employs a two-layer structure as a heat insulating material. In other words, thermal shock resistance is required mainly on the furnace inner surface,
No thermal shock resistance is required because there is no rapid temperature change on the side of the stave cooler body. For this reason, in the present invention, the furnace inner layer and the stave cooler main body side layer have a two-layer structure, and the furnace inner layer has thermal shock resistance, and the stave cooler main body side layer uses a low thermal conductivity material for slow cooling overall. Is satisfied.

In other words, the slow cooling stove cooler of the present invention has a structure in which a heat insulating material is provided on the inner surface of the furnace of the stave cooler main body, so that the cooling capacity of the stave cooler is not directly transmitted to the inside of the furnace, so that overcooling can be prevented. Further, even if the heat insulating material falls off, the profile in the furnace can be kept to a minimum by the stave cooler body. At least two outer sides of the inner surface of the furnace of the stave cooler main body are protruded toward the inside of the furnace to form a recess, and the recess is provided with a two-layer heat insulating material having both functions of heat shock resistance and slow cooling. The heat insulating material is less likely to be worn out and fall off.

[0014]

FIG. 1 shows a slow cooling stove cooler of the present invention.
3 will be described based on the embodiment shown in FIG. FIG. 1 (a)
(B) is a perspective view showing an embodiment of a slow cooling stave cooler of the present invention, FIG. 2 is a cross-sectional view of FIG. 1 (a), and FIG. 3 is a cross-sectional view of another embodiment.

In FIGS. 1 and 2, reference numeral 11 denotes a stave cooler body, which has a structure similar to a conventional stave cooler, which is cooled by cooling water supplied through a water cooling pipe 11a. In the embodiment shown in FIG. 1A, for example, four sides of the outer periphery are projected on the inside of the furnace on the furnace inner side surface 11b of the stave cooler body 11, and in the embodiment shown in FIG. Are projected to the inside of the furnace to form an interior recess 11c of the heat insulating material 12 described later. The portion protruding inside the furnace has a structure in which, for example, a substantially middle portion is cooled by a water-cooling pipe 11d by a cooling water supplied in a separate system from the water-cooling pipe 11a within a range that does not cause overcooling.

Reference numeral 12 denotes a heat insulating material provided in the recess 11c.
The furnace inner layer 12a and the stave cooler main body side layer 12
b has a two-layer structure. Of these, the furnace inner layer 12a
Is abrupt temperature increase due to friction of raw materials in the furnace
Thermal shock resistance to maintain sufficient strength against temperature change
For example, SiC-based or high Al_TwoO_ThreeHigh strength
Insulation material with high thermal conductivity is formed on the fired panel.
The stave cooler main body side layer 12b has a two-layer structure.
Slow cooling by lowering the overall thermal conductivity of the whole heat insulating material 12
In order to satisfy, for example, cordierite or chamotte
System and hollow Al_TwoO _ThreeLow thermal conductivity, low-strength insulation
As shown in FIG. 1 and FIG.
As shown in the figure, it is formed by pouring.

The furnace inner layer 12a and the stave cooler main body side layer 12b are not bonded to each other at the boundary so as not to restrict thermal expansion and thermal contraction therebetween. Has a high thermal conductivity, so that the followability at the time of rapid temperature decrease in the furnace is improved, the temperature difference from the furnace temperature can be reduced, and the tensile stress on the furnace inner surface can be reduced.

The slow cooling stove cooler of the present invention adopts the above-described structure, thereby lowering the cooling capacity of the entire stave cooler as compared with the conventional stave cooler to satisfy the slow cooling and to provide the heat insulating material. 12 can also be suppressed.

Next, in order to confirm the effect of the slow cooling stave cooler of the present invention, an experiment was conducted when the slow cooling stave cooler shown in FIG. The results will be described. First, without the heat insulating material 12 has a two-layer structure of this invention, the description will be given of a case where a one-layer structure, the thickness of 150mm Al ₂ O _3: 52.4 wt%, MgO: 5.2% by weight, SiO ₂ : 39.4% by weight, Fe ₂ O ₃ :
1.5 wt% cordierite-based heat insulating material [thermal conductivity λ:
1.5 kcal / mh ° C, tensile strength σ _T : 60 kgf / mm ² ,
Linear expansion coefficient α: 0.25%, Young's modulus E: 30,000 kgf /
mm ² , thermal shock coefficient K: 30 kcal / mh ° C.], but although satisfactory in terms of slow cooling, cracks were generated,
The life was found to be short.

Further, SiC having a thickness of 150 mm: 74% by weight,
Al ₂ O ₃ : 19 wt%, SiO ₂ : 4 wt% SiC-based heat insulating material [thermal conductivity λ: 14 kcal / mh ° C., tensile strength σ _T : 1]
20 kgf / mm ² , coefficient of linear expansion α: 0.44%, Young's modulus E:
30,000 kgf / mm ² , Thermal shock coefficient K: 136 kcal / mh
° C], slow cooling is not satisfactory,
There was no crack generation and the life was long.

On the other hand, the furnace inner layer 12a has a thickness of 50
mm, the same heat-insulating material as that described above, which is formed on the fired panel, is used for the stave cooler main body side layer 12.
b: 150 mm thick Al ₂ O ₃ : 50.0% by weight, SiO ₂ : 4
7.0% by weight of a chamotte-based heat insulating material [thermal conductivity λ:
1.0 kcal / mh ° C], it was possible to satisfy both slow cooling and thermal shock resistance.

[0022]

As described above, since the slow cooling stove cooler of the present invention uses the heat insulating material of the two-layer structure, both the slow cooling and the thermal shock resistance can be satisfied.
The range of material selection can be widened, equipment costs can be reduced and design can be simplified, and a stable profile can be maintained over a long period of time. Further, in the present invention, since both the stave cooler main body and the heat insulating material can be manufactured by casting, cast molding or the like, the conditions according to the furnace mold and the position in the furnace can be easily selected.
It can be changed, and optimization of the furnace body protection wall can be appropriately performed. Furthermore, as a synergistic effect of the above effects,
Management can be performed quickly and accurately.

In this embodiment, the slow cooling stove cooler of the present invention is installed at the furnace port of the blast furnace. However, the installation location is not limited to this, and the stove cooler can also be used as a water-cooled metal for a reaction furnace. . Further, in the present embodiment, the outer periphery is projected on four sides or two sides. However, for example, when the outer periphery is long in the up-down direction, the middle part in the up-down direction is also protruded, and two interior recesses of the heat insulating material may be formed. Good.

[Brief description of the drawings]

1 (a) and 1 (b) are perspective views showing one embodiment of a slow cooling stave cooler of the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is a sectional view of another embodiment.

FIG. 4 is a cross-sectional view illustrating a furnace body structure of a blast furnace.

FIG. 5 is an explanatory view showing a state of repairing a conventional furnace opening brick.

FIG. 6 is an explanatory view of a stave cooler described in JP-A-61-37904.

7A is an enlarged view of FIG. 6, and FIG. 7B is an enlarged view of another embodiment.

FIG. 8 is an explanatory view of a stave cooler described in Japanese Patent Application Laid-Open No. Hei 3-211121.

[Explanation of symbols]

 4 Furnace Shell 11 Stave Cooler Main Body 11b Furnace Inner Side 11c Concave 12 Heat Insulation Material 12a Furnace Inner Layer 12b Stave Cooler Main Body Side Layer

Claims (1)

(57) [Claims] 1. A stave cooler for protecting a furnace shell from heat load in a furnace, wherein at least two outer peripheral sides of a furnace inner side face are protruded toward the furnace inside to form a stove cooler main body having an interior concave portion of a heat insulating material. And a two-layer heat insulating material provided in the recess of the stave cooler main body. The two-layer heat insulating material has high strength and high thermal conductivity such as SiC type and high Al ₂ O ₃ type. and wherein the furnace inner layer made of heat insulating firing panel, cordierite type, chamotte type and hollow Al ₂ O ₃ based low thermal conductivity, in that it consists of stave cooler body side layer of insulating sintered panel or casting material of the low intensity Slow cooling stove cooler.