JPS6147682B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a melting furnace, a heat treatment furnace, a drying furnace, a kiln furnace,
The present invention relates to a method for manufacturing a lining material for industrial furnaces for constructing refractory and heat-insulating walls for crucible furnaces, ladles, and other fire-resistant insulation walls. Various fireproof and insulating materials have been provided as lining materials for various industrial furnaces, but for example, in industrial furnaces lined with firebricks, the surface temperature of the furnace wall becomes high, which shortens the life of the furnace. At the same time, it also had drawbacks such as requiring a long time for dissolution. Recently, various efforts have been made to save fuel, improve productivity by shortening the heating and cooling time of the furnace, extend the life of the furnace, thin the furnace wall by reducing thermal conductivity, and reduce the weight of the furnace wall. A ceramic fiber lining material with unique properties has been developed. The above-mentioned ceramic fiber lining material uses high-purity alumina and silica as its main raw materials, and is made by kneading heat-resistant fibers that have been melted into fibers with the addition of a binder, so the lining material itself is a paste-like material. It is flexible. Therefore, when using this lining material,
It is customary to apply adhesive mortar on the furnace wall bricks or furnace body iron skin in advance, and then trowel it directly on top of it, or apply it with a trowel while adjusting the thickness. It was hot. However, if the above paste-like lining material is used simply as a heat-insulating filler or an expansion allowance filler, it is fine, but when used as a fire-resistant heat-insulating lining material for constructing a furnace wall, the following There were some inconveniences like this. (b) The lining work is carried out in a narrow furnace, and the paste-like flexible material is applied with a trowel, making it extremely difficult to perform even for experienced workers and prolonging the construction period. (b) It is difficult to form a furnace wall with a uniform thickness and a beautiful wall surface without uneven coating. C. If the lining is applied thickly to the top wall of the furnace, the paste-like soft material once applied with a trowel will peel off and fall during the application process, making the lining process itself extremely difficult. D. Even if a furnace wall is constructed by applying a flexible lining material, it cannot be operated immediately after construction; dry firing for 12 hours or more is required to dry the furnace wall and achieve the desired lining effect. is necessary. E. When flexible lining material is troweled, the furnace wall is formed as a single wall, so cracks occur due to thermal expansion during furnace operation, causing cracks in the furnace wall and impairing the lining effect. Ta. F. Even if a part of the furnace wall needs to be repaired due to cracks or burnout deterioration, the entire furnace wall must be relined, making the lining cost extremely high. When the walls of a heavy oil furnace or kerosene furnace are constructed using paste-like ceramic fiber lining material, the hardness of the furnace wall is low and the texture density is coarse, so liquid fuel such as heavy oil or kerosene may leak into the furnace wall during operation of the furnace. This impregnation reduces the strength of the furnace wall and shortens the lifespan of the furnace. In addition, carbon adheres to the furnace wall due to the burner flame during furnace operation, and if this carbon layer is removed, the lining material will accumulate and peel off, leaving the furnace wall in a state where it is hollowed out. The furnace wall will be severely damaged. Therefore, conventionally, ceramic fiber lining materials have not been used for heavy oil furnaces or kerosene furnaces. The present invention eliminates the above-mentioned conventional drawbacks, and aims to provide a method for producing a lining material for an industrial furnace, which realizes forming a paste-like ceramic fiber lining material into a regular block. To explain in detail an embodiment of the manufacturing method according to the present invention, first, the main ingredients are alumina (aluminum oxide) and silica (silicon dioxide) as raw materials, and the chemical composition ratio thereof is determined according to the characteristic values. Next, the alumina-silica-based raw material is melted in an electric furnace or the like, and compressed air is blown onto the melt to blow away the molten metal to form a fiber. This fiber has excellent heat resistance and heat insulation properties, and is lightweight, and when the heat-resistant fibers are aggregated into a cotton-like form, it has excellent flexibility and thermal shock resistance. Therefore, when an inorganic binder is added to the above alumina-silica heat-resistant integrated fiber and thoroughly kneaded,
A paste-like flexible heat-resistant material is formed. Next, the flexible heat-resistant material, which is amorphous, is filled into the inside of a mold with a lower template placed on the inner bottom, and after the filling operation, an upper template is placed on the surface of the flexible heat-resistant material. Shape it into a sandwich. The upper template and the lower template are made of rubber, various synthetic resins, glass fibers, or the like. Therefore, pressure is applied to the upper surface of the upper mold plate using a suitable pressure means. In this case, the pressurizing means includes pressurizing means using air pressure, hydraulic pressure, water pressure, etc.
For example, it includes a press or other means for pressurizing using centrifugal force or vacuum pressure, and the specific pressurizing means is not limited. The pressing force applied to the flexible heat-resistant material filling via the upper mold plate was 5.
Kg/ ^cm2 or more is desirable. The flexible heat-resistant material pressurized as described above is compressed inside the mold and molded into a predetermined shape to form a block body. Thereafter, the block body is removed from the mold. At this time, since the block made of the flexible heat-resistant material is wet and sticky, the block is removed from the mold with the upper and lower templates attached to the front and back surfaces of the block. After cutting the mold, the block body, the upper mold plate, and the lower mold plate are kept in a three-part polymerized state, and the process moves to a drying process. The drying oven used in this drying process usually employs a hot air drying method, and the blocks are dried by blowing hot air onto them. If the upper and lower templates are made of a material with poor heat resistance, first
After the pre-drying is completed, the upper and lower mold plates attached to it are peeled off and removed from the block body, and then only the block body is dried with hot air at a high temperature of 100℃ or higher. Drying is carried out, and if the moisture contained in the block body is sufficiently removed through the main drying process, a standardized industrial furnace lining material is completed. In addition, if the upper mold plate and the lower mold plate are made of a material with excellent heat resistance, such as glass fiber, the block body, the upper mold plate, and the lower mold plate may be directly connected in a three-way polymerized state. It may be dried. In this case, when the main drying is completed, the upper mold plate and the lower mold plate can be easily peeled off and removed from the block body. The lining material molded in this way is formed into blocks of various shapes (usually plate-shaped) depending on the shape of the furnace wall, so when such blocks are used for constructing the furnace wall, The compression-molded block body is used as it is, or the block body is cut and molded into an appropriate shape and fixed to the inner surface of the refractory brick wall in the furnace with an adhesive, and a large number of block bodies are similarly arranged in a row and a row. The furnace wall is completed by filling the joints formed between the blocks with a paste-like coating material. The method for producing a lining material for industrial furnaces according to the present invention realizes a compression-molded ceramic fiber lining material in a fixed shape as described above, so that it has not only the characteristics of ceramic fiber but also the excellent effects as described below. It is something that demonstrates the. a) Since the furnace is constructed by arranging block bodies as lining materials vertically and horizontally, construction is easy even in a narrow furnace, making it possible to significantly shorten the construction period. b. Since a block body having a predetermined shape and thickness is used, the furnace wall thickness is uniform and the inner wall surface is beautiful. c. Even when constructing the top wall of the furnace, once the blocks are glued together, there is no risk of them peeling off and falling, and the lining work itself is easy. d) Since the compression-molded block body is dried in the final process, the furnace can be put into operation immediately after construction, and there is no need for so-called dry firing. e Since the furnace wall is constructed by arranging a large number of block bodies in parallel vertically and horizontally, it is possible to prevent the occurrence of cracks due to thermal expansion and avoid cracks in the furnace wall. f. Even if a part of the furnace wall requires repair, only that part of the block body needs to be replaced, reducing lining costs. g A paste-like heat-resistant material made by adding and kneading an inorganic binder to alumina-silica-based heat-resistant integrated fibers is flexible and sticky, so even if this material is filled into a mold, the material may stick to the mold and be removed from the mold. However, in the present invention, the material is filled between the lower mold plate and the upper mold plate inside the mold,
After cutting the mold, the upper and lower mold plates are removed from the block after pre-drying or main drying.
This allows the material to be made into regular blocks. If the material is pressurized and compression-molded and then dried, both mold plates can be easily removed from the block body and can also be easily released from the mold. h. Each block as a lining material fixed to the furnace wall has been compressed and dried and solidified in advance, so it has high hardness and strength and has a dense structure. Therefore, when constructing the furnace wall of a heavy oil furnace or kerosene furnace using this lining material, it is possible to prevent liquid fuel such as heavy oil or kerosene from impregnating the furnace wall while the furnace is operating, and also prevent the burner flame from impregnating the furnace wall. Even if carbon adheres to the furnace wall surface, it can be easily removed without damaging the furnace wall surface. Therefore, it promotes the effect of extending the life of the furnace, and can also be effectively used as a lining material for heavy oil furnaces, kerosene furnaces, etc. i. Since the block body serving as the lining material can be easily cut with any cutting tool such as a knife or planer, it can also be easily molded into any shape that suits the shape of the furnace interior. j After compression molding, the cut block is dried, so the moisture contained in the block evaporates and becomes extremely lightweight. When comparing a paste-like ceramic fiber lining material and a lining material produced by the method of the present invention, the results of an experiment showed that when both have the same volume, the former paste-like lining material weighs 2.4 kg, while the latter's The standard lining material weighed 1.1 kg, and its weight ratio was less than 1/2. Also, compared to other firebricks, etc., the weight ratio of the regular lining material was about 1/4 to 1/5. Since the lining material is extremely lightweight, the weight of the furnace wall is reduced, making it possible to save on foundation materials and structural steel materials. k Since the lining material is made of alumina and silica as main raw materials, it has extremely excellent heat resistance and heat insulation properties, and can withstand high-temperature use of around 1500°C. l In addition, when a lining material obtained by pressurized compression molding (pressing force 5 kg/cm ² ) and a lining material dried without applying pressure were tested for hardness using a rubber hardness tester (Showa type). The hardness of the pressurized lining material was 90 to 100 degrees, while that of the unpressurized lining material was 60 to 68 degrees, indicating a significant difference in hardness. m Also, when comparing a heavy oil furnace constructed using the lining material manufactured by the method of the present invention and a heavy oil furnace constructed using conventional refractory bricks (SK34#), The following experimental results were obtained.

[Table] When experimenting on the surface temperature changes of parts A, B, and C of the furnace wall in a heavy oil furnace (ceramic furnace or brick furnace) shown in Figure 1, it was found that As shown in Figure 2, the furnace wall surface temperature is at most 200℃ or less,
Also, the time required for melting the ingot (point X in the same figure)
was 34 minutes. On the other hand, brick furnaces using conventional refractory bricks
As shown in Figure 3, the furnace wall surface temperature reached a maximum of nearly 400°C, and the time required for the ingot to melt down (point Y in the figure) was 56 minutes. There was also a significant difference in fuel consumption as shown in the attached table. As described above, the lining material manufactured by the method of the present invention has not only heat resistance but also extremely excellent heat insulation properties, and it can save fuel, improve productivity by shortening furnace heating and cooling time, and improve productivity. Extending the life of the furnace,
This is an epoch-making invention that further advances the properties of ceramic fiber lining materials, such as low thermal conductivity, increased furnace wall strength and hardness, making the furnace wall thinner, and greatly reducing the weight of the furnace wall.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional diagram showing the temperature measurement position of a heavy oil reactor, and Fig. 2 shows changes in furnace surface temperature in a ceramic heavy oil reactor constructed using the lining material manufactured by the method of the present invention. FIG. 3 is a diagram showing changes in furnace surface temperature in a brick heavy oil furnace built using conventional refractory bricks.

Claims (1)

[Claims] 1 A paste-like flexible heat-resistant material made by adding and kneading an inorganic binder to alumina-silica-based heat-resistant integrated fibers is filled between a lower mold plate and an upper mold plate inside a mold, and is then pressurized. The compacted molded block is removed from the mold with both templates still attached, then dried, and after pre-drying or main drying is completed, both templates are removed from the block and the block is made into a single block. A method for producing a lining material for an industrial furnace, the method comprising: forming a lining material for an industrial furnace; 2. The method for producing a lining material for an industrial furnace according to claim 1, wherein the lower mold plate and the upper mold plate are removed from the molded block body after preliminary drying with low-temperature hot air in the drying step. 3. The method for producing a lining material for an industrial furnace according to claim 1, wherein the lower mold plate and the upper mold plate are removed from the molded block body after main drying with high-temperature hot air in the drying step.