JPH0151466B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a ceramic fiber block-like unit and a furnace wall structure for a high-temperature furnace formed by lining this unit.In particular, the present invention mainly focuses on the high-temperature heat shrinkability and strength of the conventional ceramic fiber block-shaped unit. The present invention relates to an improved heat-resistant ceramic fiber block-like unit and a furnace wall structure for a high-temperature furnace lined with this unit. Heretofore, various ceramic fiber block-shaped units or linings thereof have been proposed for the purpose of improving the heat resistance of ceramic fiber linings for furnace insulation walls and simplifying construction. For example, Japanese Patent Application Laid-open No. 48-23024 (hereinafter referred to as the conventional example) discloses a unit body made by laminating small pieces cut from ceramic fiber mat, in which the fiber plane of the small pieces constituting the unit body is A lining for an industrial furnace constructed almost perpendicular to the furnace wall has been disclosed, and Japanese Patent Laid-Open No. 51
-103108 (hereinafter referred to as Conventional Example 2), a desired number of laminated fiber felts each consisting of two or more ceramic fiber layers are placed on one side of a support plate, with the laminated side facing the support plate side. A furnace lining material is disclosed in which heat-resistant ceramic fibers are arranged and fixed vertically to the surface layer inside the furnace.
No. 134835 (hereinafter referred to as Conventional Example 3) has a ceramic fiber furnace wall structure in which a single piece of sheet-shaped ceramic fiber is wound into a roll and fixed to the furnace wall surface so that the axis of the single piece is substantially perpendicular. The body has been disclosed, and furthermore, Japanese Patent Application Laid-Open No. 113609/1986
No. (hereinafter referred to as Conventional Example 4), the interlayers and all or part of the surface of a laminate formed by laminating small pieces cut from ceramic fiber mats are made of alumina polycrystalline or mullite polycrystalline ceramic fiber and A heat and wind resistant ceramic fiber is disclosed that is coated with a paste-like coating that includes a binder. However, in the industrial furnace lining of Conventional Example 1, no cracking or peeling occurs within the units, but when the temperature inside the furnace exceeds 1200°C, the ceramic fibers open at the joints where each unit comes into contact due to thermal contraction. It is known that high heat can penetrate through the joint openings and cause damage to the furnace wall shell or backup material. In addition, in the case of the furnace lining material of Conventional Example 2, various ceramic fibers are wet-formed to shorten the fibers and weaken the entanglement between the fibers, so the obtained lining material has vibration resistance, It is known to have poor wind speed resistance. In addition, in the ceramic fiber furnace wall structure of Conventional Example 3, gaps are likely to be formed during construction in the areas where the joints between the units are perpendicular to each other, and furthermore, the four corners of the surfaces of the units exposed in the furnace are Since the bulk specific gravity is considerably smaller than that at other positions, the thermal contraction of the ceramic fibers at the four corners appears to be large, and the voids become significantly large, causing high heat to enter from these parts and cause damage to the furnace wall shell. It has been known. Furthermore, in the case of the laminate of Conventional Example 4, thermal shrinkage is suppressed in a direction parallel to the surface between the layers coated with the paste-like coating material, but perpendicular to the coated surface. There is a drawback that thermal shrinkage in the direction is not suppressed. Furthermore, even if a glue-like coating material is applied between the layers and also applied to the surface of the laminate, there is a drawback that the thermal shrinkage cannot be sufficiently suppressed from occurring in a direction perpendicular to the surface applied between the layers. It has been known.
Furthermore, it is known that even if the coating thickness of the paste-like coating material is increased, the defects that occur in each case cannot be improved. The previously proposed ceramic fiber block-like units or linings made of these units have the various drawbacks described above, and therefore have insufficient durability in high-temperature furnaces. It is an object of the present invention to provide a heat-resistant ceramic fiber block-like unit that has low heat shrinkage, high strength, excellent vibration resistance and wind speed resistance, and is inexpensive, eliminating the drawbacks of the conventional examples. The object of the present invention is achieved by providing a heat-resistant ceramic fiber block-like unit as described in the claims and a furnace wall structure for a high-temperature furnace lined with this unit. I've reached it. The heat-resistant ceramic fiber block-like unit of the present invention is made by laminating sheet-like materials obtained by cutting ceramic fiber mats, and the heat-resistant ceramic fiber block-like unit has at least one side surface of the four outer surfaces that cross the laminated surface of the block-shaped unit formed by laminating sheet-like materials obtained by cutting ceramic fiber mats. A filler containing heat-resistant ceramic fibers having higher heat resistance than the ceramic fibers constituting the mat and a binder mainly composed of an inorganic substance is filled in the open grooves formed vertically in a substantially lattice shape. It is a block-shaped unit with little heat shrinkage at high temperatures. Furthermore, a furnace wall structure for a high-temperature furnace lined with this unit has a side surface having an open groove filled with the filler of the block-shaped unit when the block-shaped unit is used for the inner wall of a high-temperature furnace. This is a furnace wall structure for a high-temperature furnace, in which the block-shaped unit is lined on the inner wall of the furnace so that the side surface facing the side surface is on the high-temperature side and the side surface is on the low-temperature side. Next, the present invention will be explained in detail. The ceramic fiber block-shaped single body that can be used for the heat-resistant ceramic fiber block-shaped single body of the present invention is a mat of ceramic fiber which is usually composed of 45 to 65 wt% alumina and the remainder substantially silica, as shown in FIG. A block-like unit made by laminating sheet-like materials,
It is a block-like unit made by laminating and curing sheet-like materials obtained by cutting ceramic fiber mats that have been uniformly impregnated with an organic binder in advance. A particularly preferred block-shaped unit is the latter block-shaped unit, which can be molded into a large size and has excellent dimensional accuracy and workability. As the heat-resistant ceramic fiber used in the heat-resistant ceramic fiber block-like unit of the present invention, ceramic fibers such as alumina polycrystalline, mullite polycrystalline, and zirconia polycrystalline fibers can be used, but conventionally commercially available ceramic fibers can be used. Any fiber can be used as long as it has better heat resistance than amorphous ceramic fiber. Further, as the inorganic binder to be mixed and used in the heat-resistant ceramic fiber, for example, colloidal silica, colloidal alumina, colloidal zirconia, basic aluminum chloride, basic aluminum lactate, aluminum phosphate, ammonium phosphate, etc. can be used. However, any two or more of these can be used in combination, and generally any binder can be used as long as it has heat resistance and binding ability. As shown in FIG. 2, the heat-resistant ceramic fiber block-like single body of the present invention has a lattice-like opening groove perpendicular to one side of the four outer surfaces that cross the laminated surface of the ceramic fiber block-like single body. is provided and the filler material is filled into the open groove. In this case, there are no particular restrictions on the width of the grooves and the spacing between the grooves provided in the block-shaped unit, but if the width of the opening is too narrow or the spacing between the grooves is too wide, the excellent features described below may be avoided. Unable to obtain properties. On the other hand, if the width of the grooves is too wide or the interval between the grooves is too narrow, the excellent properties described below will appear, but the amount of heat-resistant polycrystalline ceramic fiber used will increase, resulting in an economic disadvantage. However, the disadvantage is that the filler material separates from the block-like unit. From the above, in consideration of heat resistance and economic efficiency, the best results are obtained when the width of the grooves in the heat-resistant ceramic fiber block of the present invention is set to 2 to 20 mm, and the interval between the grooves is set to 20 to 120 mm. is obtained. Further, the width or interval of the open grooves does not necessarily have to be uniform as long as it is within the above range. for example,
In a furnace wall structure in which the inner wall of the furnace is constructed using the heat-resistant ceramic fiber block-like unit of the present invention, the width of the opening groove is from the surface exposed in the furnace, that is, the high-temperature side, to the furnace wall skin, that is, the low-temperature side. can also be gradually narrowed. This is because the thermal contraction of the ceramic fiber decreases toward the furnace wall shell, that is, toward the low temperature side. Furthermore, the depth of the groove provided in the heat-resistant ceramic fiber block-like unit of the present invention can be arbitrarily determined depending on the temperature inside the high-temperature furnace in which this unit is constructed. In order to fully exhibit the effect of the present invention, the temperature range where the furnace wall structure is constructed by constructing the furnace inner wall using the heat-resistant ceramic fiber block-like unit of the present invention is exposed to high temperatures of 800°C or higher,
That is, it is advantageous that the grooves are provided up to a temperature range in which thermal contraction of the ceramic fiber is observed. The heat-resistant ceramic fiber block-like unit of the present invention described above has the following features: (i) In the region filled with the filler material, thermal contraction in a plane in the same direction as the plane forming the lattice exhibits directionality in that plane; It can be made significantly smaller. (ii) The filler improves the strength of the filled region, and the strength does not show any directionality in a plane in the same direction as the plane forming the lattice. Furthermore, (iii) in a planar area including the bottom of the open groove filled with the filler material, a portion of the block-like single body provided with the open groove and a portion of the block-like single body provided with the open groove are different from each other. It has an excellent property of not peeling off or from the bonding interface between the filler and the block-like unit. The reason why the heat-resistant ceramic fiber block-like single body of the present invention has the extremely excellent properties described above is as follows. (b) By filling the filler in a lattice shape, the contact surface between the filler whose main component is a heat-resistant polycrystalline ceramic fiber having low heat shrinkage and the ceramic fiber block-like unit becomes wider. Therefore, the low heat shrinkage of the polycrystalline ceramic fiber is fully exhibited,
Furthermore, the low heat shrinkage of the polycrystalline ceramic fiber is exhibited without showing any directionality in the plane forming the lattice due to the non-directionality of the lattice structure. (b) By filling the filler in a grid pattern,
The high strength of the lattice structure and the non-directionality of the lattice structure are exhibited in a plane in the same direction as the plane forming the lattice. (c) The filler is deeply filled in the block-shaped unit in the same direction as the orientation direction of the ceramic fibers constituting the block-shaped unit, and furthermore, the interface where the filler and the block-shaped unit are in contact is close to each other. Because they are joined in the same way, cracks may occur due to thermal strain at the interface or between the part of the block-like single body where the groove is provided and the part of the block-like single body where the groove is not provided. There isn't. The case where the inner wall of various high-temperature furnaces is constructed using the heat-resistant ceramic fiber block-like unit of the present invention having the above-mentioned characteristics will be explained. That is, the furnace wall structure for a high-temperature furnace of the present invention can be fixed to the iron shell 7 using any conventionally known mounting method, for example, with an L-shaped or T-shaped support fitting, as shown in FIG. 3, for example. A surface formed by filling the heat-resistant ceramic fiber block-like unit with a filler as shown in FIG. It is constructed by attaching X to the inside of the furnace, and side Y facing the side to the shell 7 side. In this case, as the mounting direction of the heat-resistant ceramic fiber block-like unit, there are two possible mounting directions: one in which the laminated surfaces 2 are perpendicular to each other as shown in FIG. 2, and one in which the laminated surfaces are aligned in a single direction. The former method of attachment is preferred because the width of the joint openings due to heat shrinkage of the single ceramic fiber block becomes smaller and more uniform. In the furnace wall structure obtained in this manner, the openings of the joints between the heat-resistant ceramic fiber block-like units are extremely small, so that the furnace wall shell may be damaged due to the intrusion of high heat from inside the furnace, or the block-shaped units may be damaged. No falling off occurred due to deterioration of the supporting metal fittings.
Further, it is possible to obtain an extremely useful furnace wall structure for a high temperature furnace, which is excellent in wind speed resistance, vibration resistance, and spalling resistance. Furthermore, a joint material is applied to the joints between the heat-resistant ceramic fiber block-shaped units to further improve the suppression of thermal shrinkage, vibration resistance, and wind speed resistance of the heat-resistant ceramic fiber block-shaped units of the present invention. You can also do it. In addition, in the furnace wall structure lined with the heat-resistant ceramic fiber block-like unit of the present invention, the surface exposed to the high-temperature side of the furnace is coated for a long period of time so that it can withstand even harsher high-temperature furnaces. It is also possible to provide a coating layer that does not peel off. The reason why such a coating layer can be provided is that the heat-resistant polycrystalline ceramic fibers exposed in a lattice pattern on the high-temperature side of the furnace do not suffer from the decrease in strength seen in amorphous ceramic fibers at high temperatures. , that deterioration damage due to chemical attack such as scale or alkali that occurs when steel materials are heat treated in a high-temperature furnace is extremely difficult to occur, and that the flat surface exposed inside the high-temperature furnace as seen in Conventional Example 4 has no heat shrinkage. This is because the phenomenon that indicates the direction of suppression does not occur. Furthermore, the heat-resistant ceramic fiber block-shaped unit of the present invention is extremely advantageous in terms of cost because only a small amount of expensive heat-resistant ceramic fiber is used as a filler. As mentioned above, the heat-resistant ceramic fiber block-like unit of the present invention has better vibration resistance and better vibration resistance than the furnace lining material disclosed in Conventional Example 2.
It has significantly superior wind speed resistance, and compared to the heat-resistant ceramic fiber disclosed in Conventional Example 4,
The effect of suppressing thermal shrinkage of a single block-like substance is extremely excellent. Furthermore, the furnace wall structure for a high temperature furnace, which is lined with a heat-resistant ceramic fiber block-like unit according to the present invention, has the following advantages: Compared to other furnace wall structures, the openings of the joints between each unit due to thermal contraction at high temperatures are significantly smaller, and
It has excellent wind speed resistance and has sufficient durability at high temperatures. Hereinafter, the present invention will be explained with reference to examples. Example 1 In the fiberization process of ceramic fiber,
A solution in which the organic binder is diluted 3 times with water in advance.
The solution was continuously added to the ceramic fiber having a chemical composition of 48.1 wt% Al ₂ O ₃ and 50.8 wt% SiO ₂ so that the weight ratio was 1:1, and the obtained ceramic fiber was collected. These were laminated and pressed, dried and hardened to obtain a block-shaped molded product having a bulk specific gravity of 0.16 g/cm ³ . Using the ceramic fiber block-like single body obtained in this way, the first
Open grooves were provided in a grid pattern as shown in the table.

[Table] On the other hand, as a filler to be filled into the open grooves, a paste-like composition having the composition shown in Table 2 was prepared.

【table】

[Table] The above-mentioned composition was densely packed into the open grooves provided in the above-mentioned block-shaped single body, and then these were dried in a hot air dryer at a temperature of 105°C for 24 hours to form a heat-resistant ceramic fiber as shown in Fig. 2. A block-like simple substance was obtained. The depth of the open grooves is parallel to the surface forming the lattice of the block-like single body obtained in this way.
It was cut at 75 mm to obtain a test specimen as shown in Figure 4. Thereafter, each test piece was heated in an electric furnace to measure residual thermal shrinkage, bending strength, and compressive strength, and further a spalling resistance test was conducted. The results are shown in Table 3. The methods for measuring each of the physical properties are as follows. (i) Residual heat shrinkage: A test specimen measuring 300 mm square and 75 mm thick was heat-treated at 1400°C for 24 hours at measurement points B ₁ , B ₂ , B ₃ , and B ₄ shown in FIG. The amount of change in distance between each measurement point was measured. (ii) Bending strength: A test specimen of 300 mm square and 75 mm thick.
After heat treatment at 1400℃ for 24 hours, the span length
Measurements were made in the A direction shown in FIG. 4 at a distance of 200 mm. (iii) Compressive strength: A test specimen of 300 mm square and 75 mm thick.
After heat treatment at 1400° C. for 24 hours, measurements were taken in direction A shown in FIG. (iv) Spalling resistance test: 300mm square, thickness 75
A specimen of 15 mm in diameter was heated in an electric furnace maintained at 1400℃.
After heating for 1 minute, immediately take it out of the oven and cool it in the air for 15 minutes. This operation was repeated for 20 cycles and the presence or absence of cracking and the extent of cracking were observed for each cycle. For comparison, the residual heat shrinkage rate, bending strength, compressive strength, and spalling resistance tests were also conducted on the ceramic fiber block alone without the lattice-shaped grooves. The results are also listed in Table 3.

【table】

[Table] From the measurement results of various physical properties, it was found that compared to the heat-resistant ceramic fiber block-like single body of the present invention, the residual heat shrinkage rate was small, and the bending strength and compressive strength were high, indicating excellent physical properties. Example 2 A heat-resistant ceramic fiber block-shaped unit of the present invention (size 300 mm long, width 300 mm, thickness 300 mm, width of open groove 10 mm, interval between open grooves 50 mm, depth of open groove 75 mm) was installed so that the surface filled with this single filler in a lattice pattern was on the high temperature side and heated at 1400℃ for 100 hours. After heating, the degree of opening of the joints between the blocks was checked from inside the furnace. The results are shown in Table 5. For comparison, ceramic fiber (Al ₂ O ₃ 48.1wt%,
Blanket (SiO ₂ 50.8wt%) (bulk specific gravity
0.16g/cm ³ , thickness 25mm) was cut into 300mm squares and laminated (size: length 300mm, width 300mm,
300 mm thick) and ceramic fiber (Al ₂ O ₃ 48.1 wt%,
Blanket (SiO ₂ 50.8wt%) (bulk specific gravity
0.16g/cm ³ , thickness 25mm) was cut into 300mm squares and laminated, and then a paste-like preparation prepared according to the composition shown in Table 4 below was applied between the layers and on the entire surface. After 3 m ² of each (300 mm in length, 300 mm in width, and 300 mm in thickness) were attached to the steel shell of the ceiling of the heating furnace and heated in the same manner, the degree of opening of the joint between each laminate was checked from inside the furnace.

【table】

【table】 The results are also shown in Table 5.

[Table] The furnace wall structure constructed by constructing the heat-resistant ceramic fiber block-like single body of the present invention has significantly fewer joint openings than the furnace wall structure constructed from the conventionally known ceramic fiber block-like single body. It was small. This shows that the heat-resistant ceramic fiber block-like single body of the present invention is excellent as a ceramic fiber block-like single body constituting a furnace wall structure for a high-temperature furnace. Example 3 A single heat-resistant ceramic fiber block-shaped unit (size, length
300mm, width 300mm, thickness 300mm) was attached so that the side filled with this single filler in a lattice pattern was on the high temperature side. Thereafter, the pasty composition shown in Example 2 was applied to the surface of the heat-resistant ceramic fiber block exposed inside the furnace to a thickness of 5 mm to form a coating layer. For comparison, a single piece of ceramic fiber block shaped as a product corresponding to Conventional Example 2 prepared by the method described below was attached to the remaining half of the iron shell of the ceiling of the heating furnace. That is, as shown in Fig. 6, a slurry of three types of fibers, rock wool ceramic fiber and alumina polycrystalline ceramic fiber, is placed in a vacuum suction molding mold in which two wave-shaped partition plates are provided at equal intervals. After each slurry was poured and the agitation of each slurry subsided, the corrugated partition plate was pulled out and immediately sucked. The obtained molded product was dried at 105° C. for 2,000 hours to obtain a felt-like product. The desired number of felt-like materials thus obtained are laminated to form a sheet with a length of 300 mm and a width of 300 mm.
A laminate with a thickness of 300 mm was produced, and a 300 mm square expanded melt was fixed on the side of the laminate where the rock wool was located using air set mortar (water glass type) to form a single ceramic fiber block. was manufactured and attached to the remaining half of the iron shell of the heating furnace ceiling. The heating furnace constructed in this manner was observed from inside the furnace after it had been operated for three months (substantial heating time 650 hours). The results are shown in Table 6. The size, fuel, and usage conditions of the batch-type forging furnace are as follows. Size: 2.1W x 2.1L x 1.5H Fuel: A heavy oil Atmosphere temperature: 1360℃ (MAX 1420℃) Vibration during forging: Vertical direction MAX 110db

[Table] In the furnace wall structure constructed from the heat-resistant ceramic fiber block-like single body of the present invention, peeling of the coating material and separation and falling off of the filler material due to vibration and erosion by scale, alkali, etc. did not occur.
This means that the furnace wall structure constructed by constructing the heat-resistant ceramic fiber block-like unit of the present invention,
This shows that it is possible to provide a coating layer that has excellent vibration resistance and does not peel off over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a ceramic fiber block made by cutting ceramic fiber mat into small pieces and laminating them. FIG. 2 is a perspective view of a heat-resistant ceramic fiber block of the present invention. FIG. 4 is a perspective view showing a part of a furnace wall structure formed by constructing a heat-resistant ceramic fiber block-like unit of the present invention on a high-temperature furnace wall shell; FIG. Fig. 5 is a perspective view of the test specimen cut parallel to the surface filled with the material in a lattice shape at the depth where the filler is filled, and Fig. 6 is a plan view of the test specimen. 2 is a perspective view of a vacuum suction molding die used in Comparative Example 3. FIG. DESCRIPTION OF SYMBOLS 1... Ceramic fiber mat, 2... Laminated surface, 3... Ceramic fiber block-like unit, 4... Filler, 5... Joint, 6... Supporting metal fittings, 7... Iron shell, 8... Molding metal Frame, 9... Corrugated partition plate, 10... Wire mesh plate, X... Surface filled with filler in a lattice pattern, Y... Surface facing the surface filled with filler material in a lattice pattern.

Claims (1)

[Scope of Claims] 1. A block-like unit made by laminating sheet-like materials cut from ceramic fiber mats, wherein at least one of the four outer surfaces that cross the laminated surface of the unit is A filler containing heat-resistant ceramic fibers having a higher heat resistance than the ceramic fibers constituting the mat and a binder mainly composed of an inorganic substance, in the open grooves provided substantially vertically in a substantially lattice shape. A single piece of heat-resistant ceramic fiber block with low high-temperature heat shrinkage characterized by being filled with. 2. The heat-resistant ceramic fiber block-shaped unit according to claim 1, wherein the width of the lattice-shaped grooves is 2 to 20 mm. 3. The distance between one of the grid-shaped grooves and the adjacent groove that is spaced apart from each other in parallel is 20
A heat-resistant ceramic fiber block-shaped unit according to claim 1 or 2, characterized in that the diameter is 150 mm. 4. The heat-resistant ceramic fiber block according to any one of claims 1 to 3, wherein the ceramic fiber constituting the block-shaped unit is a ceramic fiber consisting of 45 to 65 wt% alumina and the remainder substantially silica. simple substance. 5. Claim 1, wherein the heat-resistant ceramic fiber contained in the filler is made of at least one selected from polycrystalline ceramic fibers consisting of alumina, mullite, and zirconia. The heat-resistant ceramic fiber block-shaped unit according to any one of Items 1 to 4. 6 The inorganic substance in the binder contained in the filler is
Claim 1, characterized in that it consists of at least one selected from colloidal silica, colloidal alumina, colloidal zirconia, basic aluminum chloride, basic aluminum lactate, aluminum phosphate, and ammonium phosphate. 6. The heat-resistant ceramic fiber block-shaped unit according to any one of items 5 to 6. 7. A block-shaped unit made by laminating sheet-like materials obtained by cutting pine made of ceramic fibers, which has a substantially lattice structure approximately perpendicular to at least one of the four outer surfaces that cross the laminated surface of the unit. A filler containing a heat-resistant ceramic fiber having higher heat resistance than the ceramic fiber constituting the mat and a binder mainly composed of an inorganic substance is filled in the open groove formed in the shape of the mat. When using a heat-resistant ceramic fiber block-like single piece characterized by low high-temperature thermal shrinkage for the furnace inner wall of a high-temperature furnace, the side surface having an open groove filled with filler of the block-like single piece is placed on the high-temperature side. A furnace wall structure for a high-temperature furnace, in which the block-shaped unit is lined on an inner wall of the furnace so that the side surface facing the side surface is on the low-temperature side. 8. The furnace wall structure for a high-temperature furnace according to claim 7, wherein the bottom of the groove is provided in a temperature range in which the temperature inside the block-like unit does not fall below 800°C. .