KR100799732B1 - Felt material for back filter and the like - Google Patents

Abstract

When the present invention is used in a high temperature environment such as a bag filter, the present invention efficiently collects the dust emitted from various heat facilities under high temperature, and also has good dimensional stability and has a longer service life than conventional products. Provide felt material.

To this end, a card cloth composed of silica fibers containing silica fibers is interposed between card fibers made of silica fibers which are fired after removing soluble components or organic components from raw fibers and heat-resistant organic fibers having a melting point of about 250 ° C. or higher or no melting point. Integrate the whole by needle punching. Furthermore, the convex part is formed in the fiber surface of a felt material by impregnating the dispersion liquid of a fluororesin.

Description

Felt materials such as bag filter {FELT MATERIAL FOR BACK FILTER AND THE LIKE}

1 is an enlarged cross-sectional view illustrating a card wrap used in the present invention;

2 is a schematic cross-sectional view showing an enlarged felt material for a bag filter according to the present invention;

3 is a schematic cross-sectional view showing an enlarged modification of the felt material;

4 is a schematic cross-sectional view showing a second modification of the felt material, showing an enlarged portion of the surface thereof;

It is a schematic sectional drawing which shows the 3rd modified example of a felt material, and is a figure which expandedly showed a part of the surface.

※ Explanation of symbols for main parts of drawing

1: felt material 2: silica fiber

3: heat resistant organic fiber 5: wrap

6: batangcheon 7: fluorine resin layer

8: fiber surface convex portion

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bag filter or a felt material for use in other high temperature environments, which efficiently collects dust emitted from high temperature facilities such as incinerators and boilers at high temperatures.

In Japan, the emission standard of dust is determined by the air pollution prevention law for incinerators, kilns, and coal boilers of municipal waste, industrial wastes, etc. according to the scale. It is necessary to be below the emission standard. This gas containing gas has a high gas temperature and contains a large amount of acidic substances, and the bag filter installed in these thermal facilities needs to be heat and acid resistant. For this reason, it is preferable to use a fabric such as tetrafluoroethylene fiber (PTFE fiber), polyphenylene sulfide fiber (PPS fiber), polyimide fiber, aramid fiber or needle punch felt material which is excellent in heat and acid resistance. It is common.

In recent years, the material improvement of the heat-resistant felt material is further advanced. In Japanese Patent Publication Nos. 2-14456 and 2-36704, PTFE fibers and 0.1 to 1 denyl fine glass fibers are blended and integrated into needle punching. One composite felt material is proposed. In Japanese Patent No. 2594844, PPS fibers, aramid fibers, PTFE fibers, etc. are exemplified as organic fibers added by mixing glass fibers with heat-resistant organic fibers.

In the felt material used for the bag filter, even if part of the glass fiber is mixed as described above, the glass fiber is easy to deteriorate in an acidic atmosphere even if the glass fiber is advantageous at an initial cost. It is necessary to perform frequent filter replacement in a short period of time, resulting in uneconomical results. In addition, the glass fiber is hard and brittle, so that it is easy to be cut and dropped in the carding and needle punching process, which deteriorates the working environment of felt processing. Since glass fiber is rigid one by one, it is easy to irritate the skin of a felt worker.

The present invention has been proposed in order to improve the above-mentioned problems with respect to the felt material of glass fiber mixing, and when used in a high temperature environment such as a bag filter by mainly using silica fibers having excellent acid resistance and heat resistance compared to glass fibers, It aims to provide a felt material with a considerably longer service life. Another object of the present invention is to provide a felt material which is less likely to deteriorate the working environment during felt processing. Another object of the present invention is to provide a felt material having a high collection efficiency of filter residues such as sold out and hardly causing clogging.

In order to achieve the above object, the felt material according to the present invention is a chemical and heat resistant suitable for a bag filter and the like, silica fiber which is fired after removing the soluble component or organic component from the raw fiber, and heat resistance of melting point of about 250 ° C. The card wrap (sheet-like material of a cotton-like material) which consists of organic fibers of this is integrated by needle punching through the base fabric woven with the thread containing a silica fiber. The obtained felt material is determined to a predetermined thickness and density by heat treatment.

The felt material of the present invention may be produced by integrating a card wrap made of silica fibers and heat resistant organic fibers by needle punching and impregnating a dispersion of fluororesin. In the obtained felt material, the convex part is formed in the fiber surface.

The felt material of the present invention may be produced by integrating the whole by needle punching with a card cloth made of silica fibers and heat-resistant organic fibers through a threaded woven cloth containing silica fibers and impregnating a fluorine resin dispersion. have. In the obtained felt material, the convex part is formed in the fiber surface.

In the felt material of the present invention, the base cloth is preferably a woven fabric containing silica fibers alone or a combination of woven fabrics containing silica fibers and heat resistant organic fibers. With respect to the fabric containing the silica fibers, it is preferable that about 10% to 50% by weight of the yarns constituting the fabric are silica fibers, and the rest are heat resistant organic fibers.

In the present invention, the silica fibers used for the felt body and the base fabric are produced by mainly firing after removing the soluble component or organic component from the raw fibers of the glass fibers. The most suitable silica fibers are short fibers or long fibers made of E glass, soda silica glass, borosilicate glass, soda silicate glass, soda lime glass, etc., and these fibers are acid treated to elute the soluble components and then calcined to silica. Form a skeleton.

When the felt material 1 (FIG. 2) which concerns on this invention is used for the bag filter installed in heat facilities, such as an incinerator or a boiler, since it has high chemical-resistance and heat resistance, long-term exchange is unnecessary, and It is economically advantageous in comparison. The felt material 1 is a filter other than a bag filter, and can be used in high temperature environment. The felt material can also be applied to special clothing such as heat-insulating material, buffer material, firefighting suit, wall material and the like requiring chemical resistance and heat resistance.                     

In the felt material 1, the silica fiber 2 (FIG. 1) used for a felt main body and a base fabric is also called silica glass fiber, and is baked after removing a soluble component or organic component from a raw fiber. For example, as the silica fibers 2, short fibers such as E glass, soda silica glass, borosilicate glass, and soda-lime-based glass are produced by a blow method, and the short fibers are acid-treated to elute soluble components before firing. When the silica skeleton is formed, for example, the silica content reaches about 95% or more. It is preferable to use E glass fiber which is boron silicate glass of 1% or less of alkali content generally as a raw fiber, For example, Nihonmuki Kabushiki Kaisha (Japan) etc. produce or Yoshino Kabashi Kaisha (Japan) ) Is also sold as silica fiber (article number: FY-6).

In order to obtain the silica fiber 2, the soda silicate adjusted to a viscosity suitable for spinning may be fibrous through a nozzle, and the calcined soda powder may be further evaporated by acid treatment before firing. In addition, the polymer may be calcined after removing the organic component from the raw fiber obtained by polymerizing the silicon alkoxide solution and adjusting the viscosity and spinning. In the case of these long fibers, the sizing agent may be usually cut and then used in a predetermined length. For example, the filament is produced by Enkasa or Asahi Glass Co., Ltd. (Japan).

The silica fiber 2 has much higher acid resistance and heat resistance than ordinary glass fibers. These silica fibers are essentially porous fibers and are considerably lighter than glass fibers having a softness and a specific gravity of about 2.5 when compared to ordinary glass fibers. Moreover, the thermal expansion coefficient is about 1/10 lower than glass fiber, and it is excellent in the dimensional stability in a felt material. In addition, silica fibers have higher electrical insulation resistance and lower dielectric constant and dielectric contact value than ordinary glass fibers.

On the other hand, the organic fiber 3 (FIG. 1) used by this invention is a comparatively flexible heat resistant fiber, and needs to be melting | fusing point about 250 degreeC or more or a no melting point. The felt material of the present invention is, for example, a bag filter installed in a thermal facility, and when used in a high temperature environment, the temperature of the impregnated gas often reaches around 200 ° C. Therefore, the heat resistant organic fiber added relatively high has a melting point of 250 ° C or more. Otherwise, durability will be insufficient. Moreover, "melting point" means the fiber which is difficult to measure melting | fusing point because the decomposition temperature is lower than melting temperature at the time of heating, and the fiber does not produce thermal decomposition even if it heats at about 250 degreeC.

As the organic fiber 3 of melting | fusing point about 250 degreeC or more, PTFE fiber (melting point 327 degreeC), PPS fiber (melting point 287 degreeC), metaphenylene isophthalamide fiber (melting point 325 degreeC), polyether ether ketone fiber (melting point 345) C), 66 nylon fiber (melting point 250 degreeC-260 degreeC), polyester fiber (melting point 255 degreeC-260 degreeC), heterocyclic fiber, etc. can be illustrated. Examples of the non-melting heat resistant organic fibers include polyimide fibers (glass transition point 315 ° C.), poly-p-phenylene terephthalamide fibers, poly-p-benzamide fibers, copolymerized aramid fibers and the like. These fibers may be in the form of composite fibers or mixed fibers.

As illustrated in FIG. 1, the silica fibers 2 and the heat resistant organic fibers 3 may be mixed with each other to form a web, or 100 g / m 2 to 1000 g / m 2 may be laminated according to the application using a web of each fiber alone. The wrap 5 or 5 'is formed. As shown in FIG. 2 or FIG. 3, the felt body of the card wrap 5 increases the dimensional stability of the felt material 1 through the base cloth 6, as shown in FIG. 4 or 5. By impregnating the dispersion liquid of the above, the fluororesin adhesion layer 7 may be provided, and fine convex portions 8 may be formed on the surface of the constituent fibers 9 again. 5, it is also possible to interpose the felt main body 6 through the base fabric 6, and to impregnate the dispersion liquid of a fluororesin again.

The base fabric 6 may be a multifilament woven fabric or a span woven fabric. The base fabric 6 may be a woven fabric containing silica fibers alone or a combination of woven fabrics containing silica fibers and heat resistant organic fibers. With respect to a fabric containing silica fibers, it is preferable that about 10% by weight to 50% by weight of the yarns constituting the fabric are silica fibers, and the fibers other than the silica fibers are heat resistant organic fibers, wherein the silica fibers are a total of 10 If it is less than the weight%, the dimensional stability and predetermined heat resistance of the felt material cannot be obtained as the base fabric, and even if the silica fiber exceeds 50 weight%, the physical properties of the felt material are not improved as compared with the increase in cost, and in terms of cost Uneconomical

The base fabric 6 is interposed in the middle of the bisecting card wraps 5 ', 5' as shown in FIG. 2 or FIG. 5, or arranged above or below the single card wrap 5 as shown in FIG. do. In the case of using two or three or more fabrics together as the base fabric 6, the two sheets may be arranged in combination, or the two sheets may be divided and disposed in the middle and above and below the wrap. The obtained felt material may be integrated by needle punching, and the number of needles in this needle punch may be about 250 / cm 2 to about 350 / cm 2.

In order to use the felt material 1 as a bag filter etc., the collection efficiency is improved by adjusting to predetermined thickness and density, ie, ventilation | permeability, by heat processing by a tenter plate, a hot press, a calendar, etc. In this heat processing, it heats and pressurizes for several minutes at about 200 to 300 degreeC. Finally, it is preferable to remove the lint by singing the surface of the felt material 1.

As shown in FIG. 4 or FIG. 5, the fluororesin adhesion layer 7 is formed on one or both surfaces by resin processing with fluorine resin, and is further minutely formed on the surface of the constituent fibers 9 of the felt material 10. It is possible to disperse | distribute the convex part 8. PTFE resin is common as this fluororesin. The aqueous dispersion liquid of PTFE resin is about 60 weight%, and is stabilized by adding a nonionic surfactant normally. The fluororesin used is tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene It may be a hot melt type such as ethylene copolymer (ETFE) or polyvinyl fluoride (PVF), and is preferably dispersed in water or an organic solvent to form a dispersion.

Impregnation of the fluororesin dispersion is carried out by dipping, coating or spraying with a spray gun. After impregnating a dispersion liquid, the convex part 8 of a fluororesin is disperse | distributed to the surface of the constituent fiber 9 in the felt material 10 by drying and sintering. The felt material 10 improves the collection | suction efficiency by improving the blocking effect of filtration wastes, such as a sold-out, by the fine convex part 8 which exists in the fiber surface, and it becomes difficult to produce clogging by filtration wastes.

Next, although this invention is demonstrated based on an Example, this invention is not limited to an Example.

Example 1                     

As shown in FIG. 1, the web used by this invention is 70 weight% of PTFE fiber 1 [brand name: Toyopron, a Toray Chemical Co., Ltd. product] which is fineness 6.7 denyl, and fiber diameter 6 30 micrometers of silica fiber 2 (made by Nihon Miki Co., Ltd.) of micrometers is manufactured by uniformly blending. The web is then laminated to form a card wrap 5 having a weight per unit area of 410 g / m 2.

As shown in Fig. 2, a multifilament woven fabric containing silica fibers and a multifilament woven fabric of PTFE fibers (the product name: Toyopron Figure) are used as the base fabric 6 between the two half card wraps 5 'and 5'. Needle punching is carried out by interposing two woven fabrics of Ore Industries Co., Ltd.) at 30 000 needles / cm 2. The multifilament woven fabric containing silica fibers is 50% by weight of silica fibers and 50% by weight of carbon fibers. The weight per unit area of the two woven fabrics is 240 g / m 2 in total. Furthermore, when heat-processing on a tenter plate at 300 degreeC for 3 minutes, the felt material 1 with a weight of 650 g / m <2>, thickness 1.1mm, and air permeability of 14 ml / cm <2> * second is obtained.

As for the obtained felt material 1, thermal contraction rate (240 degreeC, 24 hours) is 2.1% in length and 1.0% in width. Moreover, hot stretch rate (230 degreeC, 1 hour) is 0.5%.

Next, the collection efficiency of the felt material 1 is measured on condition of the following.

Filtration speed 3 m / min

Dust type white fused alumina (average particle size: 4㎛)

Dust concentration 5 ± 2g / ㎥

Trial period 2300 seconds (100 pulses)

As a result, the collection efficiency of the felt material 1 reaches 99.99%.                     

In order to measure the filtering effect of the felt material 1, a bag filter 130 mm in diameter and 6.0 m in length is sewn with this felt material, and it is installed in the dust collector for municipal waste incineration. The operating conditions of the dust collector are intermittent operation at a gas temperature of 190 ° C to 210 ° C and a filtration rate of 1 m / min. The impregnated gas contains 50% of water, 40 ppm of hydrogen chloride, and 10 ppm of SOx.

After seven months of operation, the bag filter had no problems. The pressure loss of the bag filter used is 1.6 kPa.

Example 2

80% by weight of PTFE fibers (trade name: propylene and Lentin Co., Ltd.) having a fineness of 0.6 to 6 deniers (average 2.2 denyls) and 20% by weight of silica fibers (made by Nihon Mukiki Kaisha) having a fiber diameter of 6 µm were uniformly mixed. Manufacture the web. The web is then laminated to form a card wrap having a weight of 480 g / m 2.

Needle punching with 320 needles / cm 2 via a double cloth of multi-filament woven fabric containing silica fibers having a weight of 120 g / m 2 per unit area between the two card wraps 5 'and 5'. do. The multifilament woven fabric containing silica fibers is 40% by weight of silica fibers and 60% by weight of carbon fibers. Moreover, when heat-processing on a tenter plate at 300 degreeC for 3 minutes, the felt material with a weight per unit area of 600 g / m <2>, thickness 1.1mm, and air permeability of 18 ml / cm <2> * sec is obtained.

As for the obtained felt material, thermal contraction rate (240 degreeC, 24 hours) is 2.0% in length and 0.6% in width. The hot stretch rate (230 ° C., 1 hour) is 0.4%.

Next, the collection efficiency of the obtained felt material is measured under the same conditions as in Example 1. As a result, the collection efficiency of the felt material 1 amounted to 99.98%.

In order to measure the filtering effect of the felt material, a bag filter having a diameter of 116 mm and a length of 3.6 m is sewn with the felt material and installed in an industrial waste incinerator. Operation conditions of this dust collector are gas temperature 180 degreeC thru | or 200 degreeC, and filtration rate 1.2m / min.

After 12 months of operation, the bag filter had no problem. The pressure loss of the bag filter used is 1.5 kPa.

Example 3

A web was prepared by uniformly blending 70% by weight of PPS fiber (trade name: Torcon, Toray Industries Co., Ltd.) and 30% by weight of silica fiber (Nihon Miki Co., Ltd. product) having a fiber diameter of 6 µm. do. The web is then laminated to form a card wrap having a weight of 430 g / m 2 per unit area.

The needle punching is carried out between the card wraps 5 'and 5' of the bipart through a base fabric of spandex woven fabric containing silica fibers having a weight of 120 g / m 2 per unit area. The multifilament woven fabric containing silica fibers is 20% by weight of silica fibers and 80% by weight of PPS fibers. After further heat treatment on the tenter plate at 220 ° C. for 3 minutes, the thin material is processed to obtain a felt material having a weight of 550 g / m 2, a thickness of 1.5 mm and an air permeability of 17 ml / cm 2.

Next, the collection efficiency of the obtained felt material is measured under the same conditions as in Example 1. As a result, the collection efficiency of the felt material 1 reaches 99.99%.

In order to measure the filtering effect of the felt material, a bag filter having a diameter of 11 6 mm and a length of 3.6 m is sewn by the felt material and installed in an industrial waste incinerator. Operation conditions of this dust collector are gas temperature of 160 degreeC-180 degreeC, and filtration rate of 1.3 m / min.

After 12 months of operation, the bag filter had no problem. The pressure loss of the bag filter used is 1.5 kPa.

Example 4

A web is prepared by uniformly blending 70% by weight of PPS fiber (trade name: torcone) having 2 degrees of fineness and 30% by weight of silica fiber (manufactured by Nippon Miki Co., Ltd.) having a fiber diameter of 6 µm. The web is then laminated to form a card wrap having a weight of 430 g / m 2 per unit area.

The needle punching is carried out between 320 pieces / cm <2> of needles through the card | cover of the multifilament woven fabric which contains the silica fiber which weighs 120g / m <2> per unit area between the two card wraps 5 'and 5'. The multifilament woven fabric containing silica fibers is 40% by weight of silica fibers and 60% by weight of flame retardant 66 nylon fibers. Further heat treatment on the tenter plate at 210 ° C. for 3 minutes yields a felt material having a weight of 550 g / m 2, a thickness of 1.5 mm, and an air permeability of 19 ml / cm 2 · second per unit area.

Next, the collection efficiency of the obtained felt material is measured under the same conditions as in Example 1. As a result, the collection efficiency of the felt material 1 amounted to 99.98%.

In order to measure the filtering effect of the felt material, a bag filter having a diameter of 116 mm and a length of 3.6 m is sewn by the felt material and installed in a dust collector for incineration of industrial waste. Operation conditions of this dust collector are gas temperature of 160 degreeC-180 degreeC, and filtration rate of 1.3 m / min.                     

After 12 months of operation, the bag filter had no problem. The pressure loss of the used bag filter is 1.5 kPa.

Example 5

The felt material is dipped in the dispersion of PTFE resin for 1 minute in order to form the fine convex part 8 in the fiber surface of the felt material 1 manufactured in Example 2. The aqueous dispersion liquid to be used has a concentration of 60% by weight of PTFE resin, and is stabilized by adding a nonionic surfactant. The obtained felt material 10 (FIG. 5) is made to dry and sinter after impregnating the dispersion liquid of PTFE resin about 20 g / m <2>, and the convex part 8 with a fine fluororesin is formed in the whole surface.

The felt material 10 is improved by the fine convex part 8 which exists in the whole surface, and the blocking effect of filtration wastes, such as a sold-out, improves and collection efficiency becomes high. The clogging of the felt material 10 is unlikely to occur due to the filter dregs, and the filter dregs taken by filtration are easily removed, and thus the felt material 10 can be used for a longer period of time as a bag filter.

Example 6

In order to form the fine convex part 8 on the fiber surface of the felt material 1 manufactured in Example 4, the said felt material is dipped in the dispersion of PFA resin for 1 minute. The aqueous acid solution to be used has a concentration of 60% by weight of PFA resin and is stabilized by adding a nonionic surfactant. The obtained felt material 10 (FIG. 5) is impregnated with about 20 g / m <2> of dispersion of PTFE resin, and is dried and sintered, and the convex part 8 with a fine fluororesin is formed in the whole surface.

Felt material 10 is improved by the fine convex portion 8 present on the surface of the fiber to block the effect of filtering residues such as sold out, and the collection efficiency is increased. The clogging of the felt material 10 is unlikely to occur due to the filter dregs, and the filter dregs taken by filtration are easily removed, and thus the felt material 10 can be used for a longer period of time as a bag filter.

The felt material which concerns on this invention uses the card wrap which consists of silica fiber and heat resistant organic fiber, and interposes the base fabric woven from the thread containing a silica fiber. Silica fibers are lighter than ordinary glass fibers, have a low coefficient of thermal expansion, much higher acid resistance and heat resistance, and are flexible. Accordingly, the felt material of the present invention is excellent in dimensional stability, and thus is difficult to deteriorate even in an acidic atmosphere, and can be used for a long time even after treating the impregnated gas containing a large amount of an acidic substance. When the felt material of the present invention is used for a bag filter or the like installed in various heat facilities, replacement is unnecessary for two years or more, and it can be saved even in terms of the number of people for replacement work and time. With respect to the felt material of the present invention, silica fiber is cheaper than PTFE fiber, which is very expensive even if it is more expensive than glass fiber, and the amount of PTFE fiber or the like is reduced as a whole, which is economical.

Since the felt material of this invention contains a silica fiber in a felt main body and a base fabric, since the whole is comparatively flexible, a fiber rarely falls out in the process of carding and needle punching. For this reason, a good working environment can be maintained in felt processing, and skin irritation of an operator such as glass fiber does not occur.

In the felt material of the present invention, by impregnating the dispersion of the fluororesin to form fine convex portions on the fiber surface, the blocking effect of the filter residues such as dust is improved, and the collection efficiency is further increased. If the fiber surface convex part containing a fluororesin is formed, clogging by filtration waste will be less likely to occur, and it will also become easy to remove the filtration waste taken out by filtration. The felt material with the fiber surface convex part containing a fluororesin increases the dimensional stability at the time of use, and can be used for a long time, and the strength retention rate of a bag filter etc. can also be fully maintained for many years.

Claims (6)

As a chemical-resistant and heat-resistant felt material, sheet-like material of a cotton-like material composed of silica fibers fired after removing soluble components or organic components from raw fibers and heat-resistant organic fibers having a melting point of 250 ° C. or higher or no melting point A felt material in which a whole is integrally formed by needle punching through a base cloth woven with a yarn containing silica fibers, and determined to a predetermined thickness and density by heat treatment. As a chemical-resistant and heat-resistant felt material, sheet-like material of a cotton-like material composed of silica fibers fired after removing soluble components or organic components from raw fibers and heat-resistant organic fibers having a melting point of 250 ° C. or higher or no melting point And a convex portion formed on the surface of the fiber by integrating the needle by punching, setting it to a predetermined thickness and density by heat treatment, and impregnating the dispersion of the fluorine resin. As a chemical-resistant and heat-resistant felt material, sheet-like material of a cotton-like material composed of silica fibers fired after removing soluble components or organic components from raw fibers and heat-resistant organic fibers having a melting point of 250 ° C. or higher or no melting point On the other hand, convex portions are formed on the surface of the fiber by integrating the whole by needle punching through a cloth fabric woven with a yarn containing silica fibers, determining the thickness and density by heat treatment, and impregnating the dispersion of the fluororesin again. Felt material. The method according to claim 1 or 3, A base material is a woven material containing silica fibers alone or a woven fabric containing silica fibers and a heat resistant organic fiber. The method according to claim 1 or 3, Felt material, characterized in that 10% by weight to 50% by weight of the yarn constituting the fabric containing silica fibers are silica fibers. The method according to any one of claims 1 to 3, As silica fibers used for the felt body and the base fabric, short fibers or long fibers are produced from boron silicate glass, soda silica glass, borosilicate glass, soda silicate glass, soda-lime-based glass, and the like and acid-treated to obtain soluble components. Felt material characterized by eluting and calcining to form a silica skeleton.

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