JP7569702B2 - Furnace lining and its construction method - Google Patents

Description

The present invention relates to furnace linings and their construction methods.

As a fireproof structure for a furnace body, a furnace lining is known that includes a ceramic fiber block arranged on the inner side of the furnace shell and a cloth or blanket arranged to cover the ceramic fiber block. The ceramic fiber block has a thickness of, for example, about 250 mm and is arranged to cover the entire inner surface of the furnace shell, so a relatively large amount is used, depending on the size and type of the furnace body. Therefore, from the viewpoint of cost, relatively inexpensive ceramic fiber blocks that contain dust that has not become fibers (called shot) are generally used. On the other hand, the cloth or blanket arranged to cover the ceramic fiber block is required to contain as little dust as possible (called non-shot), so a relatively expensive crystalline ceramic alumina fiber cloth or blanket is used.

Patent Document 1 discloses an invention related to furnace linings for heating furnaces, heat treatment furnaces (annealing furnaces), etc. According to Patent Document 1, it is possible to prevent scratches on the surface of treated steel sheets caused by dust flying from the furnace lining material, and to economically prevent the heat-resistant cloth from falling off or dropping from the insulating wall. Figure 1 of Patent Document 1 shows a furnace lining comprising a ceramic fiber block, an alumina cloth placed on its surface, and an alumina rope sewing the alumina cloth to the ceramic fiber block.

Patent Document 2 discloses an invention related to a furnace lining applied to continuous annealing equipment and the like. According to Patent Document 2, this furnace lining is said to be free from deterioration over the long term. Figure 2 of Patent Document 2 illustrates a furnace lining that includes an amorphous ceramic fiber block, a crystalline alumina fiber blanket placed on its surface, and a U-shaped stud pin that fixes the crystalline alumina fiber blanket to the amorphous ceramic fiber block.

JP 2002-364985 A JP 2006-10107 A

The furnace lining described in Patent Document 1 has room for improvement in terms of maintenance frequency, since the alumina rope deteriorates in a relatively short time depending on the atmospheric gas inside the furnace. The furnace lining described in Patent Document 2 can solve the problem of deterioration, but has room for improvement in terms of the time required for installation. In addition, stud pins, which have excellent heat resistance, are expensive, so the furnace lining described in Patent Document 2 also has room for improvement in terms of its high cost.

The present invention provides a furnace lining and its manufacturing method that can be installed in a relatively short time and requires sufficiently low maintenance frequency.

The method for constructing a furnace lining according to the present invention includes the following steps.
(A) A step of forming a ceramic fiber layer on the inner surface of the furnace shell.
(B) placing a crystalline alumina fiber blanket over the surface of the ceramic fiber layer;
(C) A step of fixing the crystalline alumina fiber blanket to the ceramic fiber layer by attaching a fixing member made of the crystalline alumina fiber blanket so that the fixing member penetrates the crystalline alumina fiber blanket and reaches the ceramic fiber layer.

By using a crystalline alumina fiber blanket as the fixing member, the fixing member is less likely to deteriorate, and the frequency of maintenance can be sufficiently reduced. The crystalline alumina fiber blanket constituting the fixing member may be made of the same material as the crystalline alumina fiber blanket covering the ceramic fiber layer, or a different material, but it is preferable that they are made of the same material. For example, the fixing member can be obtained by punching the crystalline alumina fiber blanket for covering the ceramic fiber layer into a predetermined shape. From the viewpoint of the strength of the fixing member and the suppression of deterioration, the bulk density of the crystalline alumina fiber blanket constituting the fixing member is preferably 130 kg/ ^m3 or more.

Since the step (C) can be performed using a simple insertion tool, the furnace lining can be installed in a relatively short time. For example, the installation tool may have a pointed tip and cover at least a part of the surface of the fixing member to reinforce it. When such an insertion tool is used, the step (C) includes, for example, the following steps:
(c1) reinforcing the fixation member by covering at least a portion of a surface of the fixation member with an insertion tool having a sharp tip.
(c2) bringing the fixing member together with the insertion tool into the ceramic fiber layer;
(c3) Removing the insertion tool.

In step (C), it is preferable to attach the fixing member at an angle of 0 to 75° with respect to the normal to the surface of the ceramic fiber layer. For example, if the ceramic fiber layer has a multi-layer structure formed by folding or stacking a blanket made of ceramic fibers, the fixing member can be attached at an angle to the surface of the ceramic fiber layer so that the fixing member penetrates the multiple layers that make up the ceramic fiber layer. This allows the crystalline alumina fiber blanket to be fixed more stably and reliably by the fixing member.

The furnace lining according to the present invention comprises a ceramic fiber layer arranged on the inner surface side of the furnace shell, a crystalline alumina fiber blanket arranged so as to cover the surface of the ceramic fiber layer, and a fixing member for fixing the crystalline alumina fiber blanket to the ceramic fiber layer, the fixing member being arranged so as to penetrate the crystalline alumina fiber blanket and reach the ceramic fiber layer, and the fixing member is made of the crystalline alumina fiber blanket. With this furnace lining, since the fixing member is made of crystalline alumina fiber blanket, deterioration is unlikely to occur, and the frequency of maintenance can be sufficiently reduced.

From the viewpoint of stably and reliably fixing the crystalline alumina fiber blanket, it is preferable that the fixing member is U-shaped with a first part and a second part extending parallel to each other and a connecting part connecting the first part and the second part, the first part and the second part reaching the ceramic fiber layer and the connecting part being exposed on the inner surface side of the furnace lining. The fixing member may have a rectangular body part and a head part having a width wider than the body part, the body part reaching the ceramic fiber layer and the head part being exposed on the inner surface side of the furnace lining. By abutting the head part of the fixing member against the crystalline alumina fiber blanket, the crystalline alumina fiber blanket is sandwiched between the head part and the ceramic fiber layer, and the crystalline alumina fiber blanket can be fixed more stably and reliably.

The present invention provides a furnace lining and a manufacturing method thereof that can be constructed in a relatively short time and requires sufficiently low maintenance frequency.

FIG. 1 is a perspective view showing an example of a furnace body provided with a furnace lining according to the present invention. FIG. 2 is a cross-sectional view showing a schematic configuration of a ceramic fiber block. FIG. 3 is a perspective view illustrating an example of a fixing member. FIG. 4(a) is a cross-sectional view showing a state in which a fixing member is attached perpendicularly to the surface of the ceramic fiber layer, and FIG. 4(b) is a cross-sectional view showing a state in which a fixing member is attached obliquely to the surface of the ceramic fiber layer. 5(a) and 5(b) are cross-sectional views showing a schematic diagram of the process of applying the furnace lining. FIG. 6 is a perspective view showing a schematic example of an insertion tool. FIG. 7 is a plan view showing a schematic diagram of another example of the fixing member. 8(a) and 8(b) are cross-sectional views showing typical modified examples of furnace linings, and FIGS. 8(c) and 8(d) are cross-sectional views showing typical insertion tools used in the construction of these furnace linings. 9(a) and 9(b) are cross-sectional views showing schematic modifications of the furnace lining.

Below, an embodiment of the present invention will be described with reference to the drawings. In the description, the same elements or elements having the same functions will be designated by the same reference numerals, and duplicate descriptions will be omitted.

Figure 1 is a perspective view showing a schematic example of a furnace body equipped with an inner lining. The furnace body 20 shown in Figure 1 includes a furnace shell 1 and an inner lining 10 provided on the inner surface 1a side of the furnace shell 1. The furnace body 20 is, for example, an annealing furnace, in which annealing treatment of steel sheets is performed. Note that the furnace body 20 is not limited to annealing treatment, and may be used for heat treatment of steel sheets, etc. The inner lining 10 includes a ceramic fiber layer 5 formed on the inner surface 1a side of the furnace shell 1, a crystalline alumina fiber blanket 7 arranged to cover the surface 5a of the ceramic fiber layer 5, and a fixing member 8 that fixes the crystalline alumina fiber blanket 7 to the ceramic fiber layer 5.

The ceramic fiber layer 5 is made of ceramic fibers. Specific examples of ceramic fibers include refractory ceramic fibers (RCF) and biosoluble fibers (BSF). From the viewpoint of cost, the ceramic fibers do not necessarily need to be highly crystalline, and may be relatively inexpensive amorphous ceramic fibers. The thickness of the ceramic fiber layer 5 is, for example, about 100 to 400 mm. From the viewpoints of heat insulation, workability, cost, etc., the bulk density of the ceramic fiber layer 5 is, for example, 80 to 200 kg/ ^m3 .

The ceramic fiber layer 5 is made of a number of ceramic fiber blocks 3 arranged in a regular pattern. The ceramic fiber blocks 3 are formed into a block shape by, for example, stacking ceramic fiber blankets with a thickness of about 10 to 50 mm in a folded state. As shown in FIG. 2, the ceramic fiber blocks 3 have a multi-layer structure, and the layers 3a are arranged so as to be perpendicular to the inner surface 1a of the furnace shell 1. As a result, the surface 5a is formed by the folded parts 3b of the ceramic fiber blocks 3. As shown in FIG. 1, the layers 3a of two adjacent ceramic fiber blocks 3 may be arranged so as to be perpendicular to each other. Note that, although FIG. 2 shows an example of a ceramic fiber block 3 made of a folded blanket, it may also be a block (not shown) in which the blankets are simply stacked without being folded.

The crystalline alumina fiber blanket 7 has a property called non-shot. That is, the content of dust that causes shots in the crystalline alumina fiber blanket 7 is sufficiently small. Therefore, by covering the ceramic fiber layer 5 that may cause shots with the crystalline alumina fiber blanket 7, defects due to shots can be sufficiently reduced. The thickness of the crystalline alumina fiber blanket 7 is, for example, about 6 to 15 mm. From the viewpoint of strength and deterioration suppression, the bulk density of the crystalline alumina fiber blanket 7 is preferably 130 kg/m ³ or more. The upper limit of this bulk density is, for example, 160 kg/m ^3. As the crystalline alumina fiber blanket 7, for example, an alumina fiber blanket having a shot content of 45 μm or more of 3% or less can be used.

The fixing member 8 is for fixing the crystalline alumina fiber blanket 7 to the ceramic fiber layer 5. The fixing member 8 is obtained by processing the crystalline alumina fiber blanket into a predetermined shape by die-cutting or the like. By using the crystalline alumina fiber blanket as the fixing member 8, the fixing member 8 is less likely to deteriorate, and the frequency of maintenance can be sufficiently reduced. The crystalline alumina fiber blanket constituting the fixing member 8 may be made of the same material as the crystalline alumina fiber blanket 7 or a different material, but it is preferable that the material is the same. For example, the fixing member 8 can be obtained by die-cutting the crystalline alumina fiber blanket 7 into a predetermined shape. The bulk density of the crystalline alumina fiber blanket constituting the fixing member 8 is preferably 130 kg/m ³ or more from the viewpoint of the strength of the fixing member 8 and the suppression of deterioration. The upper limit of this bulk density is, for example, 160 kg/m ³ .

Figure 3 is a perspective view showing the structure of the fixing member 8. As shown in this figure, the fixing member 8 is U-shaped. That is, the fixing member 8 has a first part 8a and a second part 8b that extend parallel to each other, and a connecting part 8c between the first part 8a and the second part 8b. The first part 8a and the second part 8b reach the ceramic fiber layer 5, and the connecting part 8c is exposed on the inner surface side of the furnace lining 10. By using the U-shaped fixing member 8, the crystalline alumina fiber blanket 7 can be stably and reliably fixed to the ceramic fiber layer 5. The reason why the fixing member 8 does not easily fall off when attached to the ceramic fiber layer 5 and the crystalline alumina fiber blanket 7 is due to the frictional force between the respective parts.

As shown in FIG. 4(a), the fixing member 8 may be attached perpendicularly to the surface 5a of the ceramic fiber layer 5, or as shown in FIG. 4(b), the fixing member 8 may be attached obliquely to the surface 5a of the ceramic fiber layer 5. By attaching the fixing member 8 obliquely to the surface 5a, the fixing member 8 tends to penetrate the layer 3a of the ceramic fiber block 3 that constitutes the ceramic fiber layer 5. This allows the crystalline alumina fiber blanket to be fixed more stably and reliably by the fixing member.

Next, a description will be given of a method for constructing the furnace lining 10. The method for constructing the furnace lining 10 includes the following steps.
(A) A step of forming a ceramic fiber layer 5 on the inner surface 1a side of the furnace shell 1.
(B) A step of disposing a crystalline alumina fiber blanket 7 so as to cover the surface 5 a of the ceramic fiber layer 5 .
(C) A step of fixing the crystalline alumina fiber blanket 7 to the ceramic fiber layer 5 by attaching a fixing member 8 so that the fixing member 8 penetrates the crystalline alumina fiber blanket 7 and reaches the ceramic fiber layer 5.

Figure 5(a) is a cross-sectional view showing a ceramic fiber layer 5 formed by arranging multiple ceramic fiber blocks 3 on the inner surface 1a side of the furnace shell 1. Each ceramic fiber block 3 is fixed to the furnace shell 1 by, for example, bolts and nuts.

Figure 5 (b) is a cross-sectional view that shows a schematic state in which the crystalline alumina fiber blanket 7 is arranged to cover the surface 5a of the ceramic fiber layer 5. Until the crystalline alumina fiber blanket 7 is fixed by the fixing member 8, the crystalline alumina fiber blanket 7 may be temporarily fixed to the ceramic fiber layer 5 using, for example, a pin (not shown).

Figure 6 is a perspective view showing a schematic example of an insertion tool for carrying out step (C). The insertion tool 9 shown in this figure is for reinforcing the fixing member 8 and inserting it into the crystalline alumina fiber blanket 7 and the ceramic fiber layer 5. The insertion tool 9 has a sufficiently high strength against the crystalline alumina fiber blanket 7 and the ceramic fiber layer 5, and has a sharp tip. The insertion tool 9 is configured to accommodate the rectangular fixing member 8 in a bent U-shape. The insertion tool 9 is configured to cover the outer surface, inner surface, and one side surface of the U-shaped fixing member 8, and the other side surface of the fixing member is open.

When the insertion tool 9 is used, the step (C) includes, for example, the following steps.
(c1) Reinforcing the fixing member 8 by covering at least a portion of the surface of the fixing member 8 with the insertion tool 9.
(c2) Bringing the fixing member 8 together with the insertion tool 9 to the ceramic fiber layer 5 .
(c3) Removing the insertion tool 9.

Step (c1) can be performed by inserting the fixing member 8 into the insertion tool 9 through the opening 9a of the insertion tool 9. Step (c2) can be performed by inserting the insertion tool 9 into the crystalline alumina fiber blanket 7 and the ceramic fiber layer 5 while the fixing member 8 is inserted in the insertion tool 9. In step (c2), the fixing member 8 may be inserted perpendicularly to the surface 5a of the ceramic fiber layer 5 (see FIG. 4(a)), or may be inserted obliquely to the surface 5a of the ceramic fiber layer 5 (FIG. 4(b)). In the latter case, it is preferable to attach the fixing member at an angle of more than 0° and not more than 75° with respect to the normal line of the surface 5a of the ceramic fiber layer 5. The lower limit of this angle is, for example, 10°, and may be 20°. The upper limit of this angle may be, for example, 45°. When the ceramic fiber layer 5 is applied to a thin area, this angle may be 45° or more.

Step (c3) can be performed as follows. First, after performing step (c2), the angle of the insertion tool 9 is changed so that the connecting portion 8c of the fixing member 8 is exposed outside the insertion tool 9 through the opening 9a. Then, only the insertion tool 9 can be pulled out.

According to the above embodiment, by using a crystalline alumina fiber blanket as the fixing member 8, the fixing member 8 is less likely to deteriorate, and the frequency of maintenance can be sufficiently reduced. In addition, since the fixing member 8 can be efficiently inserted into the crystalline alumina fiber blanket 7 and the ceramic fiber layer 5 using a simple insertion tool 9, the furnace lining 10 can be constructed in a relatively short time.

Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment. For example, in the above embodiment, the U-shaped fixing member 8 is exemplified, but the fixing member may have other shapes. For example, the fixing member 18 shown in FIG. 7 is T-shaped and has a rectangular body portion 18a and a head portion 18b having a width wider than that of the body portion 18a. In this case, the body portion 18a reaches the ceramic fiber layer 5 and the head portion 18b is exposed on the inner surface side of the furnace lining. By abutting the head portion 18b against the crystalline alumina fiber blanket 7, the crystalline alumina fiber blanket 7 is sandwiched between the head portion 18b and the ceramic fiber layer 5, and the crystalline alumina fiber blanket 7 can be stably and reliably fixed.

As shown in FIG. 8(a), the main body 18a may be inserted perpendicularly to the surface 5a of the ceramic fiber layer 5, or as shown in FIG. 8(b), the main body 18a may be inserted so that it bends midway. In the former case, the fixing member 18 may be inserted by reinforcing it with a pair of insertion tools 19A and 19B as shown in FIG. 8(c), for example. Both of the pair of insertion tools 19A and 19B have sharp tips and a flat shape. On the other hand, in the latter case, the fixing member 18 may be inserted by reinforcing it with a pair of insertion tools 19C and 19D as shown in FIG. 8(d), for example. Both of the pair of insertion tools 19C and 19D have sharp tips and a curved shape.

As shown in FIG. 9(a), the main body 18a may reach the ceramic fiber layer 5, bend toward the crystalline alumina fiber blanket 7, and reach the outside of the crystalline alumina fiber blanket 7. In this case, the main body 18a and the head 18b may be engaged. Also, as shown in FIG. 9(b), a member 18c similar to the head 18b may be provided on the tip side of the main body 18a to prevent the crystalline alumina fiber blanket 7 from coming off. In this way, in order to make the tip of the main body 18a reach the outside of the crystalline alumina fiber blanket 7, an insertion tool with a larger curvature than the pair of insertion tools 19C and 19D shown in FIG. 8(d) may be used. In this case, since the tip of the insertion tool also reaches the outside of the crystalline alumina fiber blanket 7, the insertion tool does not have to be configured as a pair, and may be, for example, cylindrical.

1...furnace shell, 1a...inner surface, 3...ceramic fiber block, 3a...layer, 3b...folded portion, 5...ceramic fiber layer, 5a...surface, 7...crystalline alumina fiber blanket, 8, 18...fixing member, 8a...first portion, 8b...second portion, 8c...connecting portion, 9, 19A, 19B, 19C, 19D...insertion tool, 9a...opening portion, 10...furnace lining, 18a...main body, 18b...head, 18c...member, 20...furnace body

Claims (8)

(A) forming a ceramic fiber layer on the inner surface of a furnace shell;
(B) disposing a crystalline alumina fiber blanket over the ceramic fiber layer;
(C) attaching a fixing member made of a crystalline alumina fiber blanket so that the fixing member penetrates the crystalline alumina fiber blanket and reaches the ceramic fiber layer, thereby fixing the crystalline alumina fiber blanket to the ceramic fiber layer;
A method for installing a furnace lining, comprising: 2. The method for constructing a furnace lining according to claim 1, wherein the fixing member is made of a crystalline alumina fiber blanket having a bulk density of 130 kg/m3 or ^more . The process (C) comprises:
(c1) reinforcing the fixation member by covering at least a portion of a surface of the fixation member with an insertion tool having a sharp tip;
(c2) bringing the fixing member together with the insertion tool into the ceramic fiber layer;
(c3) withdrawing the insertion tool; and
The method for constructing a furnace lining according to claim 1 or 2, comprising: The method for constructing a furnace lining according to any one of claims 1 to 3, wherein in step (C), the fixing member is attached at an angle of 0 to 75° with respect to the normal to the surface of the ceramic fiber layer. A ceramic fiber layer disposed on the inner surface side of the furnace shell;
a crystalline alumina fiber blanket disposed to cover a surface of the ceramic fiber layer;
a fixing member for fixing the crystalline alumina fiber blanket to the ceramic fiber layer;
Equipped with
the fixing member is disposed so as to pass through the crystalline alumina fiber blanket to the ceramic fiber layer;
The material of the fixing member is a crystalline alumina fiber blanket. The fixing member is
a first portion and a second portion extending parallel to each other;
A connection portion between the first portion and the second portion;
and
6. The furnace lining according to claim 5, wherein the first portion and the second portion reach the ceramic fiber layer and the connecting portion is exposed on the inner surface side of the furnace lining. The fixing member is
A rectangular body portion;
A head portion having a width greater than that of the body portion;
having
6. The furnace lining according to claim 5, wherein the body portion extends to the ceramic fiber layer and the head portion is exposed on the inner surface side of the furnace lining. The furnace lining according to any one of claims 5 to 7, wherein the fixing member is attached at an angle of 0 to 75° with respect to the normal to the surface of the ceramic fiber layer.

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