JP6897488B2 - Furnace wall structure - Google Patents

Description

The present invention relates to a furnace wall structure of a heating furnace.

In the steel industry, in order to improve the heat insulating property of a heating furnace that heats steel pieces, it is common practice to install ceramic fiber blocks in a grid pattern on the side wall of the heating furnace or the inner surface of the ceiling. For example, Patent Document 1 discloses a ceramic fiber block having a rectangular parallelepiped block body obtained by folding ceramic fibers in a knot shape and a mounting bracket attached to the block body.

When the ceramic fiber block is used in a heating furnace for a long period of time, the scale (FeO, Fe ₂ O ₃ ) generated in the furnace reacts with the ceramic fiber, and the ceramic fiber is worn out. The worn ceramic fiber block is replaced with a new one, but there is a problem that it takes a lot of time and effort to replace the ceramic fiber block.
On the other hand, as a method of repairing a worn ceramic fiber block, a coating technique of spraying or troweling an amorphous refractory is known. However, since the amorphous refractory contains a large amount of water, it shrinks due to its own weight and heat rise. There is a problem that the amorphous refractory falls off.
Further, when the above coating technique is applied to an unused ceramic fiber block, the amorphous refractory also falls off, so that there is a problem that a sufficient wear prevention effect cannot be obtained.

Therefore, in Patent Document 2, a group of ceramic fiber modules (ceramic fiber blocks) fixed to support members such as iron skins at predetermined intervals, and individual surfaces of these modules are covered, and both ends thereof are modules. A furnace wall structure composed of a ceramic fiber blanket interposed and fixed in an interval between them is disclosed.
Further, in Patent Document 3, a ceramic fiber blanket is put on the damaged portion of the ceramic fiber block, and the ceramic fiber block and the ceramic fiber blanket are sewn with a ceramic fiber rope so as to penetrate the ceramic fiber blanket in the thickness direction. The repair method is disclosed.

JP-A-2007-278590 Japanese Unexamined Patent Publication No. 1-134197 Japanese Unexamined Patent Publication No. 2005-55010

The furnace wall structure described in Patent Document 2 has a problem in implementation work that a gap is generated between the ceramic fiber blanket and the surface on the working side of the ceramic fiber block. Since the scale existing in the furnace atmosphere invades the gap, the ceramic fiber blanket is worn from both the operating surface side and the gap side, and there is a problem that the ceramic fiber blanket has a short life. As the wear of the ceramic fiber blanket progresses, the ceramic fiber blanket falls off, which directly leads to significant wear of the ceramic fiber block.
In addition, the ceramic fiber block shrinks in the width direction during operation. Therefore, there is a problem that the supporting force of the ceramic fiber blanket interposed between the ceramic fiber blocks is lowered and the ceramic fiber blanket falls off, and the effect of protecting the ceramic fiber block is impaired.

According to the repair method described in Patent Document 3, it is not necessary to replace the ceramic fiber block, but the ceramic fiber rope is damaged by the scale and the ceramic fiber blanket falls off. Therefore, there is a problem that the effect of protecting the ceramic fiber block is impaired and the wear of the ceramic fiber block progresses.

The present invention has been made in view of such circumstances, and it is possible to significantly reduce the dropout of the ceramic fiber blanket covering the operating surface of the ceramic fiber block and improve the durability of the ceramic fiber block as compared with the conventional case. It is intended to provide a furnace wall structure.

In order to achieve the above object, in the first invention, a ceramic fiber block in which ceramic fiber blankets A are laminated and each has a vertical dimension and a horizontal dimension of 100 mm or more and a furnace wall thickness direction dimension of 30 mm or more is formed by fastening means. In the furnace wall structure arranged in a grid pattern on the inner wall of the furnace,
A ceramic fiber blanket B having a maximum thickness of 50 mm is arranged on the working surface side of the ceramic fiber block row in which the ceramic fiber blocks are continuously arranged in one direction.
The ends of the ceramic fiber blanket B are pressed toward the inner wall side of the furnace by the back surfaces of the ceramic fiber blocks located at both ends in the row direction of the ceramic fiber block row whose working surface is covered by the ceramic fiber blanket B to be pinched. It is characterized by being done.

Further, in the second invention, ceramic fiber blocks in which ceramic fiber blankets A are laminated to have a vertical dimension and a horizontal dimension of 100 mm or more and a furnace wall thickness direction dimension of 30 mm or more are formed on the inner wall of the furnace by fastening means. In the furnace wall structure arranged in a shape,
A ceramic fiber blanket B having a maximum thickness of 50 mm is arranged on the working surface side of the ceramic fiber block row in which the ceramic fiber blocks are continuously arranged in one direction.
The ceramic fiber block C located at both ends in the row direction of the ceramic fiber block row whose working surface is covered with the ceramic fiber blanket B, and the ceramic fiber block C arranged outside in the row direction of the ceramic fiber block C and adjacent to the ceramic fiber block C. The ceramic fiber blanket B is interposed between the ceramic fiber block D and the end portion of the ceramic fiber blanket B is pressed toward the inner wall side of the furnace by the back surface of the ceramic fiber block D and is sandwiched. It is characterized by.

Here, the "back surface of the ceramic fiber block" and the "back surface of the ceramic fiber block D" may be either a ceramic fiber block composed of the ceramic fiber blanket A or a fastening means for fixing the ceramic fiber block to the inner wall of the furnace. ..

In the first and second inventions, the working surface of the ceramic fiber block row in which the ceramic fiber blocks are continuously arranged in one direction is covered with the ceramic fiber blanket B, and the end portion of the ceramic fiber blanket B is the row of the ceramic fiber block row. By fixing to the inner wall of the furnace at both ends in the direction or at positions outside it, the surface of the ceramic fiber blanket B and the surface on the operating side of the ceramic fiber block are compared with the case where the surface of each ceramic fiber block is covered with the ceramic fiber blanket B. The gap between them becomes smaller, and it becomes difficult for the scale to enter the gap.
Further, since the end portion of the ceramic fiber blanket B is sandwiched between the back surface of the ceramic fiber block and the inner wall surface of the furnace, the ceramic fiber blanket B is hard to fall off.

Further, in the second invention, hot air enters between the ceramic fiber block C whose working surface is covered by the ceramic fiber blanket B and the ceramic fiber block D whose working surface is not covered by the ceramic fiber blanket B. However, since the ceramic fiber blanket B bent in a crank shape blocks the hot air, the rise in the iron skin temperature is suppressed and the heat insulating property of the furnace wall is improved.

Further, in the furnace wall structure according to the first and second inventions, the ceramic fiber block and the ceramic fiber blanket B are regarded as unused products, and the heating ray shrinkage rate of the ceramic fiber blanket A defined by JIS R3311. The heating ray shrinkage rate B (%) of A (%) and the ceramic fiber blanket B may be set to A ≧ B.

By making the heat ray shrinkage rate of the ceramic fiber blanket B equal to or smaller than the heat ray shrinkage rate of the ceramic fiber blanket A constituting the ceramic fiber block covered by the ceramic fiber blanket B, the ceramic fiber blanket B is less likely to break. Therefore, the effect of protecting the ceramic fiber block is improved.

In the furnace wall structure according to the present invention, the working surface of the ceramic fiber block row in which the ceramic fiber blocks are continuously arranged in one direction is covered with the ceramic fiber blanket B, and the end portion of the ceramic fiber blanket B is the row of the ceramic fiber block row. Since it is fixed to the inner wall of the furnace at both ends in the direction or at a position outside the furnace, the gap between the ceramic fiber blanket B and the surface on the operating side of the ceramic fiber block can be reduced as compared with the conventional case. As a result, the scale is less likely to enter the boundary region between the ceramic fiber blanket B and the ceramic fiber block, the falling off of the ceramic fiber blanket B is suppressed, and the durability of the ceramic fiber block can be improved.

It is an exploded perspective view for demonstrating the fixing method of a ceramic fiber block. The arrangement of the ceramic fiber blocks in the heating furnace is shown, (A) is a schematic view of the ceramic fiber block group viewed from the side, and (B) is a schematic view of the ceramic fiber block group viewed from the front. It is an exploded perspective view of the furnace wall structure which concerns on 1st Embodiment of this invention. It is a schematic diagram for demonstrating the problem which occurs when the thickness of the ceramic fiber blanket B exceeds 50 mm. It is an exploded perspective view of the furnace wall structure which concerns on 2nd Embodiment of this invention. (A) is a partially enlarged view of the furnace wall structure according to the first embodiment of the present invention, and (B) is a partially enlarged view of the furnace wall structure according to the second embodiment of the present invention.

Subsequently, an embodiment embodying the present invention will be described with reference to the attached drawings, and the present invention will be understood.

Ceramic fiber blocks are arranged in a grid pattern on the inner surface of the furnace wall (furnace inner wall) such as the side wall and ceiling of the heating furnace. As shown in FIG. 1, the ceramic fiber block 10 comprises a block body 11 made of ceramic fiber, a support metal fitting 16 which is a fastening means for fastening the ceramic fiber block 10 to the inner surface of the furnace wall 13, and a support metal fitting 16 as a block body. It is roughly composed of a beam material 17 for mounting on the 11.

The block body 11 is formed by laminating sheet-shaped ceramic fiber blankets A12 to form a rectangular parallelepiped shape, and the length of one side of the block body 11 is about 100 mm to 600 mm. In the present embodiment, the strip-shaped ceramic fiber blanket A12 is folded into a kudzu shape to form a block body 11.

The beam material 17 for mounting the support hardware 16 to the block body 11 has a substantially inverted T shape, and a strip-shaped tab (not shown) provided at the center of the beam body protrudes from the block body 11. In this state, the beam body is inserted into the fold portion (valley fold portion) of the block body 11. By inserting a tab protruding from the block body 11 into the slit 16a formed in the support metal fitting 16 and bending it, the support metal fitting 16 is fixed to the block body 11 via the beam material 17.

The furnace wall 13 is composed of an iron skin 14 and a heat insulating castable 15 lined on the inner surface of the iron skin 14. When fixing the ceramic fiber block 10 to the furnace wall 13, the procedure is as follows (see FIG. 1).
First, the clip 18 to which the bolt 18a is attached is attached to the support hardware 16 of the ceramic fiber block 10. Next, the ceramic fiber block 10 is pressed against the heat insulating castable 15, and the bolt 18a of the clip 18 attached to the support hardware 16 is inserted into the bolt hole 13a formed in the furnace wall 13. Then, the washer 19b is attached to the bolt 18a exposed on the outer surface of the iron skin 14, and the nut 19a is screwed to fix the ceramic fiber block 10 to the inner surface of the furnace wall 13.

As shown in FIGS. 2A and 2B, the ceramic fiber blocks 10 are arranged so that the directions of the C surfaces are orthogonal to each other between the adjacent ceramic fiber blocks 10. The surface A is formed by laminating the front and back surfaces of the ceramic fiber blanket A12, the surface B is formed by laminating the side surfaces of the ceramic fiber blanket A12, and the surface C is formed by laminating the mountain folds of the ceramic fiber blanket A12. It is a surface that has been made.

Next, a furnace wall structure capable of improving the durability of the ceramic fiber block 10 as compared with the conventional one will be described. The ceramic fiber block 10 may be an unused product or a used product.
[Furnace wall structure according to the first embodiment of the present invention]
In the furnace wall structure according to the present embodiment, as shown in FIG. 3, the ceramic fiber block rows 21 in which the ceramic fiber blocks 10 are continuously arranged in one direction (in the present embodiment, four are continuously arranged in the X direction). The ceramic fiber blanket B20 is arranged on the working surface side of the ceramic fiber block 10c, and the ends of the ceramic fiber blanket B20 are located at both ends in the row direction of the ceramic fiber block row 21 whose working surface is covered by the ceramic fiber blanket B20. It is pressed against the inner surface side of the furnace wall 13 by the back surface and is pinched.

In the present embodiment, the ceramic fiber block rows 21 are arranged in two rows in the Y direction, and the operating surfaces of the two rows are covered with one ceramic fiber blanket B20.

The working surface of the ceramic fiber block row 21 continuously arranged in one direction is covered with one ceramic fiber blanket B20, and the ends of the ceramic fiber blanket B20 are fixed to the inner wall of the furnace at both ends in the row direction of the ceramic fiber block row 21. Then, the gap between the ceramic fiber blanket B20 and the working side surface of the ceramic fiber block 10 becomes the same or slightly larger at the time of construction than when the surface of each ceramic fiber block 10 is covered with the ceramic fiber blanket B20. During operation, the absolute amount of heat shrinkage of the ceramic fiber blanket B20 becomes larger than when the surface of each ceramic fiber block 10 is covered with the ceramic fiber blanket B20, and thus becomes smaller. As a result, scale intrusion during operation can be reduced, the durability of the ceramic fiber blanket B20 can be improved, and the amount of wear of the ceramic fiber block 10 can be reduced.

Further, in the furnace wall structure according to the present embodiment, since the end portion of the ceramic fiber blanket B20 is sandwiched between the back surface of the ceramic fiber block 10c and the inner surface of the furnace wall 13, the ceramic fiber blanket B20 does not fall off and is durable. The sex is stable.

The ceramic fiber block 10 is formed by laminating ceramic fiber blankets A12 and having a vertical dimension and a horizontal dimension of 100 mm or more and a thickness of 30 mm or more (furnace wall thickness direction dimension), respectively.

Among the vertical, horizontal, and thickness dimensions of the ceramic fiber block 10, the minimum vertical and horizontal dimensions of a commercially available product is 100 mm. In the present invention, the vertical and horizontal dimensions of the ceramic fiber block 10 are set to 100 mm, and since the durability of the ceramic fiber block 10 has been confirmed, the vertical and horizontal dimensions of the ceramic fiber block 10 are set to 100 mm or more.
The minimum size of the commercially available product is 100 mm, but the thickness of the ceramic fiber block 10 is set to 30 mm or more because the ceramic fiber block 10 in service may be worn to a remaining thickness of about 30 mm.
Although the maximum size of one side of the ceramic fiber block 10 is not limited, the ceramic fiber block 10 is assumed to have a maximum width of 600 mm for a commercially available ceramic fiber blanket and the product is used as the ceramic fiber blanket A12. The maximum value of one side is 600 mm.

The maximum thickness of the ceramic fiber blanket B20 is 50 mm.
When the ceiling or side wall is targeted as the inner wall of the furnace, if the thickness of the ceramic fiber blanket B20 exceeds 50 mm, the weight of the ceramic fiber blanket B20 makes it easy for the ceramic fiber blanket B20 to break 20a (see FIG. 4), and the ceramic fiber. The protective effect of the ceramic fiber block 10 by the blanket B20 is not stable.
On the other hand, the lower limit of the thickness of the ceramic fiber blanket B20 is not specified, but the thinnest thickness of the commercially available ceramic fiber blanket is 6 mm, and the ceramic fiber blanket B20 having a thickness of 6 mm or more should be used. Can be done.

When the ceramic fiber block 10 and the ceramic fiber blanket B20 are unused products, the heating ray shrinkage rate A (%) of the ceramic fiber blanket A12 and the ceramic fiber blanket B20 defined in JIS R3311 “Ceramic fiber blanket”. It is preferable that the heating ray shrinkage rate B (%) is A ≧ B. By setting A ≧ B, the durability of the ceramic fiber blanket B20 can be improved.
When A ≧ B, the tension of the ceramic fiber blanket B20 generated during the operation of the furnace is smaller than that in the case of A <B, and the deterioration of the ceramic fiber blanket B20 is suppressed. As a result, the durability of the ceramic fiber blanket B20 is sufficiently exhibited, and the amount of wear of the ceramic fiber block 10 can be reduced.

[Furnace wall structure according to the second embodiment of the present invention]
In the furnace wall structure according to the present embodiment, the ceramic fiber blocks 10 are continuously arranged in one direction (in the present embodiment, four are continuously arranged in the X direction), and the ceramic fibers are arranged on the operating surface side of the ceramic fiber block row 21. The point that the blanket B20 is arranged is the same as that of the first embodiment, but as shown in FIG. 5, it is located at both ends in the row direction of the ceramic fiber block row 21 whose working surface is covered by the ceramic fiber blanket B20. A ceramic fiber blanket B20 is formed between the ceramic fiber block (ceramic fiber block C) 10c and the ceramic fiber block 10c arranged on the outer side in the row direction of the ceramic fiber block 10c and the adjacent ceramic fiber block (ceramic fiber block D) 10d. The end portion of the ceramic fiber blanket B20 is inserted and pressed toward the inner surface side of the furnace wall 13 by the back surface of the ceramic fiber block 10d to be sandwiched.

Also in this embodiment, the ceramic fiber block rows 21 are arranged in two rows in the Y direction, and the operating surfaces of the two rows are covered with one ceramic fiber blanket B20.

In the furnace wall structure according to the first embodiment, as shown in FIG. 6A, the arrangement shape of the end portion of the ceramic fiber blanket B20 is C-shaped, and the ceramic fiber block 10c and the ceramic fiber block Hot air infiltrates through the gap between 10d and heats the iron skin 14.
On the other hand, in the furnace wall structure according to the second embodiment, as shown in FIG. 6B, since the end portion of the ceramic fiber blanket B20 is bent like a crank, the ceramic fiber block 10c and the ceramic fiber block 10d The hot air that has entered the gap between the two is blocked by the ceramic fiber blanket B20 and does not heat the iron skin 14. As a result, it is possible to reduce the temperature rise of the iron skin 14 due to long-term operation.

Although the embodiments of the present invention have been described above, the present invention is not limited to the configuration described in the above-described embodiments, and is considered within the scope of the matters described in the claims. It also includes other embodiments and variations thereof. Further, various changes and combinations of the above-described embodiments may be made as long as the gist of the present invention is not deviated. For example, in the above embodiment, the ceramic fiber block rows are two rows, but one row may be used, or three or more rows may be used.
In the above embodiment, the method of fixing the ceramic fiber block to the iron skin is the nut method outside the furnace, but the nut method inside the furnace may also be used.

The verification test carried out for verifying the effect of the present invention will be described.
The ceiling of the heating furnace, where the atmosphere inside the furnace is about 1100 ° C, was targeted for construction.
The ceramic fiber block was manufactured by folding an unused ceramic fiber blanket A (thickness 25 mm). There are two sizes of the ceramic fiber block: length 100 mm × width 100 mm × thickness (furnace wall thickness direction) 100 mm and length 300 mm × width 300 mm × thickness (furnace wall thickness direction) 300 mm.

The support hardware was attached to the block body, and the ceramic fiber block was fixed to the inner wall surface of the furnace using bolts attached to the back surface of the support hardware (the surface opposite to the surface in contact with the ceramic fiber block). The inner wall of the furnace is composed of an iron skin and a heat insulating material arranged inside the iron skin.

The number of rows of ceramic fiber blocks whose working surface is covered by the ceramic fiber blanket B was two, and the test was carried out by changing the number of ceramic fiber blocks constituting one row.

As the ceramic fiber blanket B, an unused ceramic fiber blanket B having a thickness of 25 mm, 50 mm, and 62.5 mm was used.
The end of the ceramic fiber blanket B is fixed by pressing it toward the inner wall side of the furnace by the back surface of the ceramic fiber block located at the end of the ceramic fiber block row or the back surface of the ceramic fiber block adjacent to the ceramic fiber block row. did.

Table 1 shows a list of test results.
The wear rate index in the table was calculated as follows.
After measuring the amount of wear of the ceramic fiber block 10 to 15 months after construction and converting it to the amount of wear per year (mm / year), for the ceramic fiber block whose vertical and horizontal dimensions are 100 mm. Divides the wear rate of the ceramic fiber block by the wear rate of the ceramic fiber block of Comparative Example 1 to obtain the wear rate index. For the ceramic fiber block having a vertical and horizontal dimension of 300 mm, the ceramic fiber The wear rate of the block was divided by the wear rate of the ceramic fiber block of Comparative Example 2 to obtain the wear rate index.
In some cases, the iron skin temperature was measured.

The following tendencies were observed in the examples.
Immediately after construction, the atmosphere inside the furnace containing iron powder etc. invades the gap between the ceramic fiber block and the ceramic fiber blanket B, causing the ceramic fiber block to wear at a constant wear rate. When the wear of the ceramic fiber blanket B progresses and the gap is widened, the wear rate of the ceramic fiber block increases, and when the ceramic fiber blanket B peels off, the wear rate of the ceramic fiber block increases remarkably.

The following can be seen from Table 1.
-In all the examples, the wear rate index was less than 1.00.
-As the number of ceramic fiber blocks belonging to the ceramic fiber block row increases, the wear rate index decreases (comparison between Examples 2 and 4).
When the heating line shrinkage rate A (%) of the ceramic fiber blanket A and the heating line shrinkage rate B (%) of the ceramic fiber blanket B are A ≧ B, the wear rate index decreases (comparison of Examples 4 to 6). , Comparison of Examples 7 and 8).
-Pressing the end of the ceramic fiber blanket B on the back surface of the ceramic fiber block adjacent to the ceramic fiber block row lowers the iron skin temperature (comparison of Examples 4 and 7, comparison of Examples 6 and 8).

In the verification test, unused ceramic fiber blocks with thicknesses of 100 mm and 300 mm were used, but the same wear rate reduction effect is obtained when the ceramic fiber block worn to a thickness of 30 mm is covered with an unused ceramic fiber blanket B. Was recognized.

10, 10c, 10d: Ceramic fiber block, 11: Block body, 12: Ceramic fiber blanket A, 13: Furnace wall, 13a: Bolt hole, 14: Iron skin, 15: Insulated castable, 16: Support hardware (fastening means) , 16a: Slit, 17: Beam material, 18: Clip, 18a: Bolt, 19a: Nut, 19b: Washer, 20: Ceramic fiber blanket B, 20a: Break, 21: Ceramic fiber block row

Claims (3)

A furnace wall structure in which ceramic fiber blocks A are laminated and each having a vertical dimension and a horizontal dimension of 100 mm or more and a furnace wall thickness direction dimension of 30 mm or more are arranged in a grid pattern on the inner wall of the furnace by fastening means. In
A ceramic fiber blanket B having a maximum thickness of 50 mm is arranged on the working surface side of the ceramic fiber block row in which the ceramic fiber blocks are continuously arranged in one direction.
The ends of the ceramic fiber blanket B are pressed toward the inner wall side of the furnace by the back surfaces of the ceramic fiber blocks located at both ends in the row direction of the ceramic fiber block row whose working surface is covered by the ceramic fiber blanket B to be pinched. The furnace wall structure is characterized by being ceramic. A furnace wall structure in which ceramic fiber blocks A are laminated and each having a vertical dimension and a horizontal dimension of 100 mm or more and a furnace wall thickness direction dimension of 30 mm or more are arranged in a grid pattern on the inner wall of the furnace by fastening means. In
A ceramic fiber blanket B having a maximum thickness of 50 mm is arranged on the working surface side of the ceramic fiber block row in which the ceramic fiber blocks are continuously arranged in one direction.
The ceramic fiber block C located at both ends in the row direction of the ceramic fiber block row whose working surface is covered with the ceramic fiber blanket B, and the ceramic fiber block C arranged outside in the row direction of the ceramic fiber block C and adjacent to the ceramic fiber block C. The ceramic fiber blanket B is interposed between the ceramic fiber block D and the end portion of the ceramic fiber blanket B is pressed toward the inner wall side of the furnace by the back surface of the ceramic fiber block D and is sandwiched. The furnace wall structure is characterized by. In the furnace wall structure according to claim 1 or 2, the ceramic fiber block and the ceramic fiber blanket B are regarded as unused products, and the heating ray shrinkage rate A (%) of the ceramic fiber blanket A as defined by JIS R3311. The furnace wall structure is characterized in that the heating ray shrinkage rate B (%) of the ceramic fiber blanket B is A ≧ B.

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