JPH043609Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Field of Application] The present invention relates to a filter for high-temperature gas such as gas discharged during combustion, and more specifically, the present invention relates to a filter for high-temperature gas such as gas discharged during combustion. This relates to a heat-resistant filter that collects particles. [Conventional technology] Conventionally, high-temperature filters have been made of refractory molded bodies with a honeycomb structure, or filters made of ceramic fiber as a base material with the addition of various inorganic binders, made into thin paper, and then corrugated from this thin paper. Are known. In addition, molded products formed into plate shapes using silica-alumina ceramic fibers have recently become known. The silica/alumina ceramic fiber used as this raw material is not only relatively easy to form using conventional vacuum forming methods, but also has a high fireproof and heat-insulating effect, so it can be formed into various shapes and used as a lining material for combustion chambers. It is the most popular heat-resistant inorganic fiber that is widely used as a heat insulator for molten nonferrous metals. [Problems to be solved by the invention] However, due to the manufacturing method of silica-alumina ceramic fiber, not only is it not possible to obtain a uniform fiber diameter, but also irregular shaped ceramic granules (hereinafter referred to as shots) are produced in the form of 30-50 Weight percentages are also included. That is, in order to fiberize a silica-alumina composition dissolved at a high temperature, methods have been adopted in which the composition is blown away with high-pressure air or fiberized by the centrifugal force of a rotating drum. As a result, in the case of a silica-alumina composition having a narrow range of suitable fiber-forming viscosity, some of the resulting fibers are thick, some are thin, and some are shot. Therefore, since molded products using silica-alumina ceramic fibers made in this way are used with the shot removed, their structure is similar to that of ordinary refractories, in that they are compactly molded with a particle size blend. Despite having a large body and plenty of pores, there was a pressure loss when high-temperature gas was passed through it. In addition, the cause of pressure loss is that mullite crystals precipitate in silica/alumina ceramic fibers at about 900°C and change to crystalline fibers.
It is well known that cristobalite crystals also begin to precipitate from around 1200℃. It is also well known that when the structure changes from glassy to crystalline, the fibers break and become pulverized. When exposed to high temperatures in this way, the fine fibers are gradually cut,
It was unsuitable as a filter because it caused clogging. In other words, when used as a filter that allows high-temperature gaseous substances to pass through, not only will the ventilation resistance vary locally, but the overall pressure loss will be large, and only equipment that can increase the inlet pressure can be used. Ta. Furthermore, honeycomb structured ceramic molded bodies and corrugated filters used as high-temperature gas filters have the advantage of having small pressure loss and a constant pore diameter, but on the other hand, they have a complicated structure and are expensive to produce. However, it also had the disadvantage that a large shape could not be obtained. In order to solve these drawbacks, this invention strives to provide a filter that can be easily produced and has the lowest possible pressure loss as a high-temperature filter. (Means for solving the problem) That is, this invention contains 40% by weight or more of shots with a particle size of 44 μm or more generated when a silica/alumina mixed composition is made into fibers, and the remainder is silica/alumina. A heat-resistant filter made of a fibrous material, an inorganic binder, and an organic binder, characterized in that the shot is reinforced and fixed by the silica/alumina fibrous material, the inorganic binder, and the organic binder. A heat-resistant filter that allows high-temperature gaseous substances to pass through. [Operation] The diameter of the shot generated when the silica and alumina mixed composition is dissolved and fiberized is approximately 1000 μm.
The shapes are as shown in Figures 4 to 7.The shapes are as shown in Figures 4 to 7. The shape of the oval shot shown in the figure is not constant. Therefore,
When shots of these shapes are combined, there is an advantage that the pore size is sufficient, as if the particle sizes were mixed. In addition, it has the advantage that the particle size width is large and the pores are relatively uniform. Therefore, even if a part or most of the shot is replaced with silica-alumina mullite granules or shamot granules having a particle size blend, the object of the present invention cannot be achieved. Furthermore, if the shot is less than 40% by weight, the proportion of reinforcing material will inevitably increase, resulting in smaller pores and worse ventilation resistance. Next, a fibrous material made of silica and alumina, which is the same material, is suitable as a reinforcing material for making this shot into a molded body. If the thermal properties at high temperatures are exactly the same, the molded product will be thermally stable and will have a sense of structural integrity. If the silica/alumina fibrous material used here is too thin, it will block the pores that have formed, and if it is thick, the reinforcing effect will be small, so a range of 2 to 5 μm is selected.
The inorganic binder is selected from one or more commonly used colloidal silica, colloidal alumina, viscosity, etc., or a combination of more than one. Too much inorganic binder will block the pores, and too little will have little effect. 1 to 5% by weight of the total amount of the silica-alumina shot and fibrous material is preferably selected. The organic binder is used to impart handling strength to the molded product at room temperature, and is selected from one or more combinations of commonly used starch, latex, polyacrylamide, and the like. Since these organic binders burn out at high temperatures, the amount added can be determined arbitrarily, but from a cost perspective, it is recommended that 5 to 10% by weight of the total amount of the silica/alumina shot and fibrous material be added. Suitably selected. Furthermore, the addition of organic fibers such as pulp, hemp, cotton wool, etc. for reinforcement is also more effective. [Example] An example of the method for manufacturing the heat-resistant filter of the present invention will be described below. The heat-resistant filter of this invention consists of 400g of silica/alumina fiber containing 18% by weight of shot with a particle size of 44 μm or more and shot with a particle size of 44 μm or more.
280g shot containing 90% by weight with an average particle size of approximately 50μm, 100ml colloidal silica, 100ml nitrile butadiene latex (solid content 40%), Kibushi clay
Pour 100g into 50ml of water and stir and mix thoroughly to make a slurry.Add 20ml of a 1% aqueous solution of polyacrylamide flocculant to this slurry, stir and mix, then use a paper machine to form a sheet with a thickness of 5mm. It can be produced by molding and then drying at 105°C for 8 hours. Next, the heat-resistant filter manufactured by the above-mentioned method will be explained with reference to the drawings. In FIG. 1, it is a 1-silica-alumina fibrous material,
2 - An enlarged view of a heat-resistant filter made of silica/alumina shot, 3- An inorganic or organic binder; Figure 2 is similar to Fig. 1, 4- A heat-resistant filter made of organic fiber. . Third
The figure shows a heat-resistant filter in which a part of the silica-alumina shot shown in FIG. 2 is replaced with 5-mullite particles. Figures 4 to 7 show shots generated during fiberization of silica-alumina ceramic fiber.
4 shows a true spherical shot, FIG. 5 shows a peanut-shaped shot, FIG. 6 shows a tadpole or comb-shaped shot, and FIG. 7 shows an egg-shaped shot. Figure 8 is a schematic diagram of a conventional ceramic fiber molded product. 1 is silica/alumina fiber, 2
represents shot, and 3 represents an inorganic or organic binder. [Effects of the invention] Table 1 shows the results of measuring pressure loss using the heat-resistant filter of the invention.

【table】

[Table] As can be seen from these results, a heat-resistant filter is provided that can achieve a much lower pressure loss than conventional ceramic fiber molded products. Furthermore, because the heat-resistant filter of the present invention has a small pressure loss, it can also be used for burner tiles that allow combustion gas to pass through and burn, making it an industrial breakthrough.

[Brief explanation of the drawing]

Figure 1 is an enlarged view of the heat-resistant filter of this invention.
Figure 2 is an enlarged view of the heat-resistant filter shown in Figure 1 with organic fiber added, and Figure 3 is a part of the silica/alumina shot of the heat-resistant filter shown in Figure 2 replaced with mullite granules. An enlarged view of the heat-resistant filter with the replaced configuration, Figures 4 to 7 are enlarged views showing the shape of the silica-alumina shot,
FIG. 8 is a schematic diagram of a conventional ceramic fiber molded product. Explanation of symbols, 1... Silica/alumina fibrous material, 2... Silica/alumina shot, 3...
Binding material, 4...organic fiber, 5...mullite granules.

Claims (1)

[Scope of utility model registration request] Contains 40% by weight or more of shots with a particle size of 44 μm or more generated when fiberizing a silica-alumina mixed composition, and the remainder is silica-alumina fibrous material,
A heat-resistant filter made of an inorganic binder and an organic binder, characterized in that the shot is reinforced and fixed by the silica/alumina fibrous material, the inorganic binder, and the organic binder. A heat-resistant filter that allows things to pass through.