JP6848922B2 - Mounting structure of the furnace body protection stave - Google Patents

Description

The present invention relates to a mounting structure of a furnace body protection stave used for protecting the furnace wall of a metallurgical furnace such as a blast furnace exposed to high temperature.

Conventionally, in a furnace body such as a blast furnace, a furnace body cooling device (hereinafter referred to as “stave”) has been used to protect the furnace body from the heat load inside the furnace. The stave is made of cast iron, rolled copper, cast copper, etc., and a cooling water channel is formed in the stave body. In recent years, in order to cope with the high heat load of the blast furnace body, a stave having a higher cooling capacity has been required, and as a result, the adoption of a copper stave having a high thermal conductivity is increasing.

Such a stave for protecting the furnace body is fixedly attached to the inside of the blast furnace body by using a furnace body iron skin and a bolt. FIG. 6 shows an example of the fixing structure. For example, the stave body 51 is fixed to the iron skin 61 of the blast furnace body by screwing using bolts 52 and nuts 53. The water supply / drainage pipes 54-1 and 54-2 of the stave main body 51 are provided through the holes 62 formed in the iron skin 61 of the blast furnace body, and the water supply / drainage pipes 54-1 and 54-2 are provided. Water is supplied and drained from the outside of the furnace body.

Most of the causes of the breakage of the stave are water leakage from the cooling system due to repeated heat load in the blast furnace. In particular, in recent years, the heat load on the furnace body has increased dramatically due to the increase in pulverized coal injection, and the stave has been damaged earlier than expected at the design stage. Inundation in the furnace due to such breakage of the stave hinders stable operation of the blast furnace. Therefore, if water leakage is confirmed during operation, the cooling water circulating in the stave is stopped. Due to the stoppage of the cooling water, the stave is exposed to the high temperature in the furnace and the wear caused by the raw materials, so that the stave body itself disappears in a short period of time. Moreover, due to the disappearance of the stave (disappearance of the cooling function), the iron skin of the blast furnace is now directly exposed to high temperatures, which causes cracks in the iron skin and its thermal deformation, making it difficult to continue the operation of the blast furnace itself. It ends up.

That is, water leakage of the stave caused by deformation of the stave due to a high heat load and damage to the pipe due to exposure to high temperature gas in the furnace occurs due to cracks in the welded joint between the water supply / drain port of the stave body and the pipe. It is estimated that there are many cases.

For water leakage caused by cracks in the welded joint between the water supply / drainage port of the stave body and the piping, for example, the so-called gas seal hardware on the outer surface of the blast furnace iron skin, as disclosed in Patent Document 1, has a bellows structure. Something to do is proposed. However, in this proposal, it was not possible to fill the circumference of the pipe with refractory in order to secure the degree of freedom of the pipe. As a result, the piping is exposed directly to the high-temperature gas in the furnace, which deteriorates its mechanical properties, and as a result, it is often damaged due to thermal fatigue due to operational fluctuations. Moreover, in this case, a back wind through which the gas in the furnace flows is generated on the back side of the stave (the side where the pipe is located), which not only adversely affects the pipe but also heats the stave body from both sides, which is further mechanical. It promoted deterioration and deformation of properties.

Japanese Unexamined Patent Publication No. 50-60408

As a method of overcoming the above-mentioned problems in Patent Document 1, as shown in FIG. 7, it is conceivable to install a steel ring for blocking gas between the iron skin of the piping portion and the stave. For example, in FIG. 7, 71 is a steel ring provided outside the water supply / drainage pipe 54-1 and between the inner surface of the iron skin 61 and the outer surface of the stave body 51, and 72 is the water supply / drainage pipe. The bellows pipe 73, which is outside the 54-1 and is provided between the outer surface of the iron skin 61 and the water supply / drainage pipe 54-1, is around the water supply / drainage pipe 54-1 and is the inner surface of the iron skin 61. It is a sealing rubber provided between the steel ring 71 and the end portion of the steel ring 71.

The steel ring 71 not only keeps an appropriate gap between the iron skin 61 and the stave body 51 when the stave body 51 is attached to the iron skin 61, but is also filled between the iron skin 61 and the stave body 51. It also has the role of shutting off refractories and securing a space where the water supply and drainage pipes 54-1 can move freely.

However, in this steel ring 71, as shown in FIG. 8, when the stave main body 51 is installed on the iron skin 61, the fire resistance between the iron skin 61 and the steel ring 71 due to the respective manufacturing and installation errors. There is a problem that a gap 81 is inevitably formed in the portion of the object 82, which makes it difficult to shut off the refractory material and the high temperature gas in the furnace. A seal rubber 73 such as silicone rubber is provided to eliminate this gap, but it has low heat resistance and disappears in long-term operation. Further, as shown in FIG. 9, since the stave body 51 itself is deformed by the heat load from the inside of the furnace, the gap 81 may be enlarged and the water supply / drainage pipe 54-1 may be exposed to the high temperature gas in the furnace. There was a problem that it became expensive.

An object of the present invention is to provide a furnace body protection stave mounting structure capable of preventing adverse effects of high-temperature gas due to back wind on the water supply / drainage pipe and the stave main body and preventing stave damage.

As a result of diligent research to solve the above-mentioned problems of the prior art and to realize the above-mentioned purpose, the inventors have come to develop a new mounting structure for the furnace body protection stave described below. It was. That is, the present invention is a mounting structure of a furnace body protection stave arranged inside the furnace body iron skin of the metallurgical furnace, and is an inner surface of the furnace body iron skin and the outside of the furnace body protection stave facing the inner surface. It is characterized in that a steel bellows pipe that extends from the furnace body protection stave toward the furnace body iron skin and surrounds a cooling pipe provided so as to penetrate the side surface is interposed. It is a mounting structure for the furnace body protection stave.

In addition, in the mounting structure of the furnace body protection stave according to the present invention configured as described above,
(1) The steel bellows tube must be non-heat-treated stainless steel.
(2) The steel bellows pipe is fixed to the outer surface of the furnace body protection stave.
(3) The steel bellows pipe has a seal rubber interposed between the inner surface of the furnace body iron skin and the end of the steel bellows pipe.
(4) The outer surface of the iron skin of the furnace body and the cooling pipe have any one of a bellows type ring structure, a structure consisting of a protective pipe and a flat plate type compensator, and a structure consisting of a protective pipe and a box type compensator. Having one seal structure,
Is considered to be a more preferable solution.

According to the mounting structure of the furnace body protection stave according to the present invention, instead of interposing a steel ring between the conventional furnace body iron skin and the furnace body protection stave, a stretchable steel bellows pipe is used. It is possible to prevent the high temperature gas from being directly exposed to the cooling pipe and the stave main body due to the back wind by the configuration in which the above is interposed. Therefore, according to the present invention, it is possible to effectively contribute to the prevention of damage to the stave. Further, since the steel bellows pipe moves according to the deformation of the stave body, the load applied to the cooling pipe can be suppressed, and the refractory intrusion at the time of replacing the stave can be prevented to improve the sealing performance. it can.

It is a figure which shows an example of the mounting structure of the furnace body protection stave of this invention. It is a figure which shows another example of the mounting structure of the furnace body protection stave of this invention. It is a figure which shows an example of the cooling pipe seal structure using the attachment structure of the furnace body protection stave of this invention. It is a figure which shows another example of the cooling pipe seal structure using the attachment structure of the furnace body protection stave of this invention. It is a figure which shows still another example of the cooling pipe seal structure using the attachment structure of the furnace body protection stave of this invention. It is a figure explaining the method of fixing the furnace body protection stave in the conventional example to the furnace body iron skin. It is a figure for demonstrating an example of the mounting structure of the conventional furnace body protection stave. It is a figure explaining an example of the problem in the mounting structure of the conventional furnace body protection stave shown in FIG. 7. It is a figure explaining another example of the problem in the mounting structure of the conventional furnace body protection stave shown in FIG. 7.

FIG. 1 is a diagram showing an example of a mounting structure of a furnace body protection stave of the present invention. In the example shown in FIG. 1, between the inner surface of the furnace body iron skin 1 and the outer surface (outside of the furnace body) of the furnace body protection stave 2 facing the inner surface, from the furnace body protection stave 2 to the furnace body iron skin 1. A point in which a steel bellows pipe 5 is interposed so as to surround a cooling pipe 4 provided so as to extend toward the outside and extend to the outside of the furnace body iron skin 1 through the through hole 3 of the furnace body iron skin 1. In addition, there is a feature of the mounting structure of the furnace body protection stave of the present invention. Reference numeral 6 is an amorphous refractory material filled between the furnace body iron skin 1 and the furnace body protection stave 2. In general, an amorphous or fixed refractory 9 is also arranged inside the furnace of the stave.

In the mounting structure of the furnace body protection stave of the present invention shown in FIG. 1, instead of the conventional steel ring, a stretchable steel bellows pipe 5 is used on the inner surface of the furnace body iron skin 1 and the furnace body protection stave. It is provided so as to surround the cooling pipe 4 which extends from the furnace body protection stave 2 and is arranged so as to penetrate the through hole 3 provided in the furnace body iron skin 1 between the outer surface of 2 and the furnace body protection stave 2. It is a structure, for example, even if the furnace body protection stave 2 is deformed by the heat in the furnace, the steel bellows 5 moves well following the deformation, which is caused by the deformation of the furnace body protection stave 2. It responds well to any gaps that occur. As a result, it is possible to prevent the exposure of the high-temperature furnace gas to the cooling pipe 4 and the furnace body protection stave 2 due to the generation of back wind (the furnace gas flows to the back side (the side where the pipe is located) of the stave). ..

Further, in the present invention, by surrounding the cooling pipe 4 with the steel bellows pipe 5, it is possible to prevent the indeterminate refractory 6 from entering when the furnace body protection stave 2 is replaced and improve the sealing property. It is also effective in making it. The reason is that when replacing the stave, after removing the existing stave, refractory remains on the iron skin side, and this refractory cannot be removed cleanly. This is because a gap remains between the two. On the other hand, the end face of the stretchable bellows tube is pressed against the remaining refractory by the stretching force of the bellows tube, so that a gap is unlikely to be formed.

In the mounting structure of the furnace body protection stave of the present invention, various stainless steels having high heat resistance are used for the steel bellows pipe 5. Further, this steel bellows tube 5 is a universal type that can be deformed not only in the axial direction, but also in the direction perpendicular to the axis when an external force is applied, and can absorb bending and misalignment. As a matter of course, it is desirable that the material has a property of quickly returning to the original shape and dimensions when the external force is removed. From this point of view, for example, it is preferable to use stainless steel which has not been heat-treated and has excellent corrosion resistance. Generally, steel bellows such as stainless steel are heat-treated for the purpose of stress relief after processing, but by not performing heat treatment after processing into bellows, it is possible to obtain bellows in a state where rigidity is maintained. .. The axial spring constant of the bellows is preferably about 20 to 100 N / mm, more preferably about 40 to 60 N / mm.

When assembling the furnace body protection stave 2 to the furnace body iron skin 1, for example, the bolts of the furnace body protection stave 2 are fastened and fixed from the outside of the furnace body iron skin 1 with nuts. At this time, as the steel bellows pipe 5 shrinks, a reaction force is generated toward the back surface of the furnace body protection stave 2 and the inner surface of the furnace body iron skin 1, so that the sealing property at these contact portions is further improved. Can be made to.

Further, one furnace body protection stave 2 has a plurality of cooling pipes 4, and the furnace body has a plurality of furnace body protection stave 2. In this case, the furnace body protection stave 2 of the present invention is present. It is not necessary to apply the mounting structure of to all the cooling pipes 4 and all the furnace body protection stave 2, but to some cooling pipes 4 and some furnace body protection stave 2 depending on the magnitude of the heat load. Can only be applied.

Furthermore, the amount of expansion and contraction of the steel bellows pipe 5 is not particularly limited, but as a result of analyzing the deformation of the furnace body protection stave 2 due to the heat in the furnace by using the finite element method, the bellows It is preferable that the deformation can be followed in a range of about 30 mm from the mounting position. Of course, it goes without saying that the required amount of expansion and contraction varies depending on the size and shape of the furnace body protection stave 2.

FIG. 2 is a diagram showing another example of the mounting structure of the furnace body protection stave of the present invention. In the example shown in FIG. 2, one end of the steel bellows pipe 5 is welded and fixed to the furnace body protection stave 2. With such a configuration, it is possible to handle the steel bellows pipe 5 and prevent it from falling off during installation, and it is possible to improve the sealing property of the mounting structure of the present invention. Further, in the example shown in FIG. 2, in the gap between the other end of the steel bellows pipe 5 and the irregular refractory 6 on the inner surface of the furnace body iron skin 1 or the inner surface of the furnace body iron skin 1, silicon rubber or the like is used. A heat-resistant sealing material 7 is provided. With such a configuration, the sealing property of the steel bellows tube 5 can be further improved. Further, when the inside of the steel bellows pipe 5 is filled with the heat insulating material 8 such as ceramic wool, the cooling pipe 4 can be protected from the high temperature gas. With the above configuration, the cooling pipe 4 can be protected from direct exposure from the high temperature gas in the furnace, and the cooling pipe 4 can be more preferably prevented from being damaged, and as a result, the furnace body can be more preferably protected. It is possible to prevent the stave 2 for damage.

3 to 5 are diagrams for explaining an example of a specific sealing structure of the cooling pipe using the mounting structure of the furnace body protection stave of the present invention, respectively. In the examples shown in FIGS. 3 to 5, the same members as those in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 3 shows a bellows type ring structure in which a bellows ring 11 is provided between the back surface of the furnace body iron skin 1 and the cooling pipe 4 and around the cooling pipe 4 in addition to the sealing structure by the steel bellows pipe 5. This is an example of the sealing structure of the cooling pipe 4.

In FIG. 4, in addition to the sealing structure by the steel bellows pipe 5, the protective pipe 12 provided between the outer surface of the furnace body protection stave 2 and the cooling pipe 4 and around the cooling pipe 4 and the furnace are shown. This is an example of a sealing structure of the cooling pipe 4 by a flat plate type compensator 13 provided around the cooling pipe 4 between the outer surface of the body iron skin 1 and the protective pipe 12.

In FIG. 5, in addition to the sealing structure by the steel bellows pipe 5, the protective pipe 12 provided between the outer surface of the furnace body protection stave 2 and the cooling pipe 4 and around the cooling pipe 4 and the furnace are shown. This is an example in which the cooling pipe 4 is sealed by a box-type compensator 14 provided around the cooling pipe 4 between the outer surface of the body iron skin 1 and the protective pipe 12.

Among the above-mentioned examples, in the case of the structure using the flat plate type compensator 13 shown in FIG. 4 and the box type compensator 14 shown in FIG. 5, the movement of the cooling pipe 4 is restricted to some extent, but even in these cases, steel is used. By using it in combination with the bellows pipe 5 manufactured by the above, gas blocking can be effectively achieved.

According to the mounting structure of the furnace body protection stave of the present invention, early damage of the furnace body protection stave due to breakage of the cooling pipe can be prevented, so that the life of the furnace body protection stave and the furnace body can be extended. be able to. For example, in the conventional example in which the steel bellows pipe is not used, assuming that the replacement due to the early breakage of the furnace body protection stave occurs in several years, if the mounting structure of the furnace body protection stave of the present invention is used, it is 10 years. It is considered that the above can be maintained in a healthy state without replacement.

The mounting structure of the furnace body protection stave according to the present invention is particularly effective for a copper stave, but it can also be applied to other stave, for example, a cast iron stave. Further, since the mounting structure of the furnace body protection stave according to the present invention can effectively prevent damage to the cooling pipe of the stave exposed to high temperature, it is also exposed to high temperature in a heating furnace other than the blast furnace. It is effective as a structure for protecting the inside of the furnace wall.

1 Furnace iron skin 2 Furnace protection stave 3 Through hole 4 Cooling pipe 5 Steel bellows pipe 6 Atypical refractory 7 Sealing material 8 Insulation material 9 Refractory 11 Bellows ring 12 Protective pipe 13 Flat plate type compensator 14 Box type Compensator

Claims (4)

It is a mounting structure of the furnace body protection stave arranged inside the furnace body iron skin of the metallurgical furnace, and is between the inner surface of the furnace body iron skin and the outer surface of the furnace body protection stave facing the inner surface. The furnace body protection stave is characterized in that a steel bellows pipe is interposed so as to extend from the furnace body protection stave toward the furnace body iron skin and surround the cooling pipe provided so as to penetrate the cooling pipe. Mounting structure. The mounting structure for a furnace body protection stave according to claim 1, wherein the steel bellows pipe is made of non-heat-treated stainless steel. The mounting structure for the furnace body protection stave according to claim 1 or 2, wherein the steel bellows pipe is fixed to the outer surface of the furnace body protection stave. The steel bellows pipe according to any one of claims 1 to 3, wherein a seal rubber is interposed between the inner surface of the furnace body iron skin and the end portion of the steel bellows pipe. The mounting structure of the described furnace body protection stave.

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