JPH06322419A - Stave - Google Patents

Abstract

(57) [Summary] [Purpose] To extend the life of staves used for cooling the walls of large melting furnaces such as blast furnaces and large heating furnaces. [Structure] This is a hybrid stave that has a ceramic layer on the front side and a casting on the back side, and has a cooling pipe built into this casting part and is integrally cast. The ceramic layer has heat insulation and wear resistance. Is formed of powdery ceramic particles having a particle size of 50 mm or less, and the particle size distribution is uniform or segregated. [Effect] The casting encloses the ceramic to improve the ceramic holding property and suppress the progress of abrasion, thereby extending the life of the stave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger used in a large smelting furnace such as a blast furnace, a large heating furnace, etc., in the case of forcibly cooling the furnace wall to protect the furnace body and extend the life of the furnace. Stave).

[0002]

2. Description of the Related Art As is well known, in large melting furnaces such as blast furnaces and various large heating furnaces, the furnace wall is forcibly cooled in order to protect the furnace body and extend the life of the furnace. As such a cooling means, as shown in FIG. 2, a stave in which a cooling pipe 5 is cast inside a casting 4 forming a stave body, a steel shell 6 on the outer surface of a furnace wall F and a refractory 1 on the inner side are provided. Installed between and fixed to the iron skin. Then, a method is known in which cooling water is passed through the post-cooling pipe 5 to cool the furnace wall F. Reference technology (JP-A-58-123805)

However, this method has the following problems.

(1) In the case where the refractory inside and the heat exchanger casting (stave) in which the cooling pipe is cast are constructed as independent walls, the refractory 1 inside the furnace is inserted through the stamp material 2. Although provided, the structural stability of the refractory 1 inside is poor, and there are cases where partial collapse or full collapse occurs early, and the life of the refractory is significantly shortened.

(2) There is a structure in which the refractory material is partially connected by a casting or a structure in which the entire refractory material is cast (a structure in which the refractory material is integrally cast), but the ability to support the refractory material with the casting material. Is weak, and the life of the refractory is somewhat longer than that of (1), but there is still a limit.

(3) When the above-mentioned phenomena (1) and (2) occur, the profile in the furnace changes abruptly, which is not preferable in the operation especially in the case of a reaction furnace.

(4) In the case of a heat exchanger cast product (staves) in which a cooling pipe is cast in the cast product, the feature is that the heat conductivity is high (cooling capacity is large). 2)
When the phenomenon of (refractory dropout) occurs, the heat exchanger castings (staves) are exposed in the furnace, which may cause overcooling depending on the reaction situation in the furnace or the part of the furnace. Insulation function equivalent to refractory is required).

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a hybrid stave which can advantageously solve the above-mentioned conventional problems.

[0009]

The first invention of the present invention is as follows:
A hybrid stave in which a ceramic layer is arranged on the front surface side and a casting is mainly formed on the back surface side, and a cooling pipe is built in this casting part and integrally cast around, and the ceramic layer has a heat insulating property and wear resistance. Is a powdery granular ceramic particle having a diameter of 50 mm or less, the second invention is the first invention, in which the average particle diameter of the ceramic particles in the ceramic layer is larger toward the surface side. The hybrid stave is characterized in that the particle size is segregated so that

[0010]

In the hybrid stave of the present invention, the ceramic layer is formed of ceramic particles having a diameter considerably larger than that of the conventional one, so that the uniformity with the casting can be strengthened, and the drop is less likely to occur. The wear of the ceramic layer is gentle, the life of the stave is extended, and the life of the furnace can be extended.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The figure shows a state in which the hybrid stave of the present invention is attached to an iron skin. In FIG. 1, reference numeral 4 denotes a cast part forming the main body of the stave, and 5 a cooling pipe, which has a stuffed portion with the cast part 4, and its ends are supply / discharge parts for the cooling medium. Reference numeral 6 denotes an iron shell forming a furnace shell, to which the stave body is attached and fixed by bolts 7.

On the inside of the furnace of the stave body (cast part) 4, a ceramic layer formed integrally with the stave body is formed. This ceramic layer has heat insulating properties and wear resistance such as oxides, nitrides, and carbides.
The particle diameter is 50 mm or less, the relatively large diameter particles of 5 mm or more are ball-shaped, and these particles are mixed,
It is integrally solidified by the binder effect, sintering or fusion.

In the present example, the particle size distribution of the ceramic particles forming the ceramic layer 8 is inclined and segregated so that it is large inside the furnace and small on the furnace shell side, and in particular, it is resistant to the abrasion effect inside the furnace. It is a heightened one. It is effective to take into consideration that the boundary between the ceramic layer 8 and the stave body (cast part) 4 has remarkable irregularities so that the ceramic and the cast part 4 are strongly integrated. It is also effective to create a fitted state as a result of making it difficult for the cast part 4 and the cast part 4 to separate.

In this example, the particle size distribution of the ceramic particles forming the ceramic layer 8 is segregated so that the average particle size becomes larger on the inner surface side of the furnace, but the average particle size is made uniform and uniform. It may be a particle size distribution. In addition, regarding the type of ceramic particles forming the ceramic layer 8 used in the present invention, the particle size constitution, the pretreatment, the condition of the cast iron, etc., in order to achieve the object of the present invention depending on the operating conditions of the furnace and the cooling conditions. Suitability conditions can be selected.

[0015]

INDUSTRIAL APPLICABILITY The hybrid stave of the present invention is preferably a ceramic (oxide, nitride, carbide, etc.) corresponding to a refractory material having heat insulating properties and abrasion resistance, and a ball-shaped one integrated with the casting. Is distributed as an integral casting on the surface of the stave (inside the furnace) composed of a casting, the following effects are obtained.

1. Casting encases the ceramics and improves the holding capacity (holding) of each ceramic, preventing the entire surface from falling off early. ──── Longer life

2. This hybrid stave also wears and melts over time after long-term use, but its change is gradual, and the profile in the furnace does not change suddenly, which is particularly preferable as a reaction furnace. ──── Stable operation

3. Surface (inside the furnace) depending on the location and application
The cooling capacity (adiabatic capacity) can be arbitrarily changed by changing the amount of ceramics distributed in. ──── Cooling capacity control

4. The structure is simple. ──── Cost reduction

The advantages such as the above are obtained.

[Brief description of drawings]

FIG. 1 is a partial cross sectional explanatory view showing an example of a hybrid stave of the present invention and a mounting state thereof.

FIG. 2 is a partial sectional explanatory view showing a conventional stave example and its mounting state.

[Explanation of symbols]

 1 Refractory 2 Stamping material 3 Cast brick 4 Stave 5 Cooling pipe 6 Iron shell 7 Mounting bolt 8 Ceramic layer F Furnace wall

Claims (2)

[Claims] 1. A hybrid stave in which a ceramic layer is arranged on the front surface side, a casting is mainly formed on the back surface side, and a cooling pipe is built in the casting portion and integrally cast around, and the ceramic layer is heat insulating and wear resistant. Particle size of 50m
A stave characterized by being formed of powdery ceramic particles of m or less. 2. The stave according to claim 1, wherein the average particle diameter of the ceramic particles in the ceramic layer is segregated so that the average particle diameter becomes larger toward the surface side.