JPS61104008A - Furnace body of blast furnace and other metallurgical furnace - Google Patents

Abstract

PURPOSE:To prevent the decrease in the cooling capacity of a stave insert-cast with cooling pipes for passage of water, etc. owing to sticking of scale, etc., thereto in a furnace body interposed with said stave in a refractory brick liner of a steel shell by providing a coating layer to the inside circumference of the cooling pipes. CONSTITUTION:The cooling water 13 is circulated into the cooling pipes 12 insert-cast in the stave 10 having a projecting part 11 to cool the refractory brick, etc. The coating layer 15 is formed on the inside surface of the pipe 12. The layer 15 may be formed of any material as far as said material has oxidation resistance and exhibits substantially no affinity to water scale 14, etc., and is generally constituted preferably of copper or copper alloy. Then even if the inside of the furnace is in severe high-temp. state, the deposit 14 of water scale, rust, etc., having poor heat transmittance is not formed on the inside surface of the pipes 12 in cooling of the projecting part 11 and therefore the heat transmittance of the water 13 and the pipes 12 is improved and the stave 10 is maintained at about <=500 deg.C.

Description

[Detailed Description of the Invention] <Object of the Invention> Industrial Application Field The present invention relates to a furnace body of a blast furnace or other metallurgical furnace.
For example, the present invention relates to a furnace body of a metallurgical furnace in which a stave in which a cooling pipe for passing a cooling medium such as cooling water is cast is interposed in refractory bricks lined with the shell of the blast furnace.

BACKGROUND OF THE INVENTION Generally, blast furnaces and other metallurgical furnaces have a structure in which the furnace body is cooled by, for example, circulation of cooling water, since the furnace body is exposed to high temperatures. For example, FIG. 5 is a partial cross-sectional view of an example of a blast furnace body incorporating a stave, which is the most typical cold W device. Brickwork is relined, and staves 3a, 3b, 3c, and 3d having protrusions and a flat stay 13 are interposed between the iron skin 1 and the refractory 2 for cooling. Of these staves with protrusions, three staves 3a, 3b, and 3C are of the type that has a protrusion in the center, and the refractory brick 2 is received by this protrusion, and staves of this type are generally i. It is called a type stave. Further, the stave 3d has a protrusion at its upper end, and is generally referred to as a gay jζ type stave. That is, upward from the bottom of the blast furnace body, the stave 3a mainly receives the bricks 2 in the range A, the stave 3b receives the bricks 2 in the range 8, and the stave 3c receives the bricks 2 in the range C.
The bricks 2 in the range D are received by the stave 3d and the furnace is constructed.

In a furnace body with this structure, the inner lining disappears relatively quickly, and the bricks may fall off rapidly, causing each stave to be exposed inside the furnace and subjected to severe heat load, and the stave's cast-in tube Scale etc. adhere to the inner surface of the protrusion, causing cooling of the protrusion.

There is a problem that the capacity decreases, and as a result, damage to the stave progresses and the life of the furnace body is shortened.

That is, the inside of a blast furnace is generally at a high temperature of 1000° C. or higher, and high-temperature gas rises from the lower part, and the lining is worn out by this upward flow, and the lining is also worn away by the downward flow of raw material from the upper part. Further, the gas in the furnace contains alkaline components, and the lining deteriorates due to this alkaline component, and in many cases, the lining disappears quickly within one to two years after firing. Moreover, when the lining is in an eroded state, as shown in FIG. 6, for example, in the lower part of the furnace as in zone A in FIG. 5, the protrusion 3a' of the stave 3a is directly exposed. When this protrusion 3a' is damaged, the bricks 2 in the range B supported by it fall off, and through this process, the bricks fall off one after another, exposing the entire stave to the inside of the furnace, where it is exposed to severe heat. receive a burden. On the other hand, in staves, scale gradually adheres to the inner surface of the cast-in tube after firing.
The cold W capacity decreases, and as a result, damage to the stave progresses, and this damage to the stave controls the life of the blast furnace body, resulting in a significant reduction in the lifespan of the furnace body, which is a major problem. It becomes.

Problems to be Solved by the Invention The present invention aims to solve the above-mentioned drawbacks.
? .

Specifically, the purpose is to solve the problem that the cooling capacity of the stave incorporated in the lining of the furnace body is reduced due to adhesion of scale and the like.

<Structure of the Invention> Means for solving the problem and its operation, that is, the furnace body according to the present invention is a furnace of a metallurgical furnace such as a blast furnace or other metallurgical furnace in which the inside of the outer skin of the metallurgical furnace is lined with refractory bricks. In a stave, a cooling pipe that circulates a cooling medium such as water is interposed between these linings. A coating layer having at least one of these properties is provided.

The present invention will now be described in more detail with reference to FIGS. 1, 2, and 3.

First, FIG. 1 is a perspective view of an example of a stave incorporated in a furnace body according to one embodiment of the present invention, and FIG. 2 is a sectional view taken along the line A--A in FIG. 1. That is, in the present invention, for example, as shown in FIG. The high temperature zones A and B are constructed using a T-shaped stave 10 as shown in FIG. This T-shaped stave 10 has a protrusion 11 formed in the center for receiving bricks, and this stay 710 is generally made of cast iron and has very low strength at high temperatures, especially at temperatures above 500°C. Cold W pipes 12 are cast into this stay 710, and cooling water 13 enters these cooling pipes 12 and drains after cooling to cool the stave 1o. In the stave 10 having this structure, on the inner surface of each cooling pipe 12, that is, on the surface in contact with the cooling water 13, water scale 14 such as carbonates and sulfates adheres due to chemical reaction as shown in Fig. 3, or rust etc. occur due to oxidation reaction. is formed, which deteriorates the cooling capacity of the stave over time.

4 In addition, when the bricks on the front side of the stave are missing as described above, the protrusion 11 of the stave 1° is exposed to a particularly harsh high temperature atmosphere, and the temperature of the inner surface of the furnace of the stave 10 is lower than that of the cooling pipe 12. Even if 1000
Reaching temperatures above ℃. For this reason, the protrusion 11 is damaged due to thermal stress or the like.

In contrast, the present invention solves these problems and improves the cooling ability of the protrusion. That is,
As shown in FIG. 1, cooling water 13 is contained in a cooling pipe 12 cast in a stave 10 having a projection 11.
circulates and cools refractory bricks, etc. In this case, the inner surface of the cooling pipe 12 is coated as shown in FIG. 1
form 15. The mouth coating may be of any material as long as it has oxidation resistance and has little affinity for water scale, but generally a coating of copper or its alloy is preferred. That is, copper and the like not only have high oxidation resistance, but also do not impair cooling ability, are good in preventing water scale formation, and can be easily formed into a coating (2) by thermal spraying, plating, or the like.

With the above configuration, the protrusion 11 of each stave 10
The coating layer 14 is formed on the inner surface of the cooling tube 12 even if the inside of the furnace is in a severe high temperature state, so that heat transfer is not carried out on the inner surface of the cooling tube 12 as in the conventional example shown in FIG. Since no deposits 15 such as bad water stains or dirt are generated,
Heat transfer between the cooling water 13 and the cooling pipe 12 is improved, and the stave 10 can be maintained at approximately 500° C. or lower. Furthermore, since the original strength of the stave can be fully developed, its function as a refractory lining receiver can be maintained for a long period of time.

In addition to the above-mentioned copper and copper alloy, the coating layer on the inner surface of the cooling tube is made of A1. A1 alloy.

Zn can be used, and these can be used alone or in combination. In addition, the installation may be done by conventional means such as electroplating, S dipping, and thermal spraying, and the coating amount is 40 to 10
A range of 0 g/a+' is preferred.

Example Next, we compared the furnace body according to the present invention with the above-mentioned configuration and the conventional furnace body to find the relationship between the cooling water velocity and the heat extraction temperature, and the results were as shown in Fig. 4. ((a) is the present invention, (b) is the conventional example) were obtained.

Note that the stave according to the present invention has a CLI coated on the inner surface of the cooling pipe with a coating of approximately 0/I12 coating, whereas the conventional example is a stave that does not have this coating layer. This is an intervention.

From FIG. 4, it can be seen that the cooling capacity of the furnace body according to the present invention is improved by more than 15% compared to the conventional example when the same cooling water velocity is maintained.

Furthermore, in the conventional example, water scale or rust formed on the inner surface of the cooling tube during use, resulting in a decrease in cooling capacity. For this reason, the cooling water speed has been increased, but even if the cooling water speed is doubled, the cooling capacity will only increase by 1% due to scale or rust, which has poor heat transfer.

On the other hand, according to the present invention, as described above, the cooling capacity can be improved without increasing the cooling water, and this can also be reduced without increasing the water supply power due to the increase in the cooling water.

<Effects of the Invention> As explained in detail above, the present invention provides a cooling tube which is provided with a coating layer having properties such as oxidation resistance on the inner surface of the cooling pipe in the inner lining of a blast furnace or other metallurgical furnace. This is a furnace body made up of

Therefore, even after a long period of use, water scale does not adhere to the inner surface of the cooling pipe, and the cooling capacity does not decrease.In particular, the protruding part of the stave can be sufficiently cooled and maintained, so the lining This prevents the lining from suddenly falling off, and there is no problem even if a part of the lining disappears.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an example of a stave installed in a furnace body according to the present invention, FIG. 2 is a sectional view taken along the line A- in FIG. 1, and FIG. 1 is a cross-sectional view similar to the line A-A in Figure 1, Figure 4 is a graph of the relationship between the cooling water flow rate and the heat removal m between the present invention and the conventional example, and Figure 5 is a graph of the furnace body of the conventional example. A partial vertical sectional view, FIG. 6, is an explanatory diagram of the state of lining erosion shown in FIG. 5. Code 1... Iron shell 2... Refractory brick 3... Flat stave 3a, 3b, 3c, 3d -=- stave 3a'...
... Protrusion 4 ... Upward flow 5 ... High-temperature raw material 10 ... G-shaped stave 11 ... Protrusion 12 ... Cooling pipe 13... Cooling water 14... Water scale

Claims (1)

[Claims] In the furnace body of a metallurgical furnace such as a blast furnace or other metallurgical furnace, in which a refractory brick is lined inside the outer skin of the metallurgical furnace, a stave is interposed in the lining and has cooling pipes for circulating a cooling medium such as water. A furnace for a blast furnace or other metallurgical furnace, characterized in that the inner periphery of the cooling pipe is provided with a coating layer having at least one of the following properties: oxidation resistance or showing almost no affinity with products such as scale. body.