KR20060069869A - Method of regenerating filter fabric and regenerated filter fabric - Google Patents

Abstract

An inexpensive highly practicable method of regenerating a spent filter fabric, in which a regenerated filter fabric retains the same pressure loss and collection capability characteristics as those of a new one and with the use thereof in no way limited, can be used at high temperature in chemically very poor environment; and an inexpensive regenerated filter fabric obtained by the method. In particular, there is provided a method (1) of regenerating a filter fabric, comprising at least a fibrillation operation of fibrillating a spent filter fabric and a nonwoven fabric forming operation of converting the fibers resulting from the fibrillation operation to a nonwoven fabric. In this method, (2) a dust removing operation of removing any dust adhering to the fibers resulting from the fibrillation operation may be performed prior to the above nonwoven fabric forming operation. Further, in this method of regenerating a filter fabric, it is preferred from the viewpoint of efficient regeneration that (3) the fibrillation operation be performed by passage through an autofibrillation machine.

Description

Regeneration method of filter cloth and regeneration filter cloth {METHOD OF REGENERATING FILTER FABRIC AND REGENERATED FILTER FABRIC}

The present invention relates to a method for regenerating filter cloth for reusing used filter cloth and a regenerated filter cloth for regenerating used filter cloth.

Most of the conventional filter cloths were disposable for practical use because of labor and cost. However, the filter cloth may adhere harmful components including dioxins as dust by its use. For this reason, incineration waste disposal and landfill waste are laborious and expensive, and are unfavorable for the global environment. For this background, there is a strong demand for effective regeneration of the used filter cloth.

Conventionally, as a regeneration technique of a filter cloth, there has been a method of regeneration by water washing to wash adhered dust with water or a cleaning agent, such as spraying water on the surface of the used filter cloth (for example, Japanese Laid-Open Patent Publication). 2003-103128).

However, such a method of washing with water can separate only a part of the dust attached to the surface layer of the constituent fibers, and most of the dust attached to the inside remains. For this reason, the pressure loss of regenerated filter cloth by water washing is much higher than that of new products. For example, in the test results shown in Table 1 below, the initial pressure loss is 106 Pa compared to the new product (70 Pa). Thus, after the regeneration, the initial pressure loss equivalent to the new product could not be obtained.

In addition, dust tends to accumulate internally due to residual dust. For this reason, the regeneration filter cloth by water washing had a very high rise in pressure loss, and the filter cloth was easily clogged. For example, in the test results shown in Table 1 below, despite the frequent backwashing to eliminate clogging, the pressure loss after 8 hours of use is 302 Pa compared to the new product (122 Pa). As such, after regeneration, the service life equivalent to that of a new product could not be obtained.

In addition, since clogging lowers the pressure loss, it is frequently necessary to backwash the jet of compressed air in the direction opposite to the flow direction to shake off the dust. However, at the time of backwashing, the interweaving of the fibers weakens momentarily, so that the dust collected once (in the inside of the filter cloth) flows out toward the outlet by the flow of dust-containing air. For example, according to the test results shown in Table 1, the cumulative outlet dust concentration after 8 hours of use is 2.15 mg / m 3 compared to the new product (1.173 mg / m 3). As such, when backwashing became frequent, the outlet dust concentration was increased, and collection efficiency equivalent to new products could not be obtained after regeneration.

In addition, not only high water pressure is applied to the surface layer of the filter cloth, but also the entanglement of the fibers is weakened by the frequent backwashing, and the strength and elongation are greatly deteriorated compared to the new product.

As a regeneration technique of another filter cloth, there has existed a renewable filter cloth coated with a hot melt binder resin or a solvent soluble binder resin (see, for example, Japanese Patent Laid-Open No. 9-253432 and Japanese Patent Laid-Open No. 2001-336054). ). This is a heat treatment or dipping treatment with a solvent on the used filter cloth to easily separate dust with high efficiency with melting of the binder resin. As a result, the pressure loss after the regeneration and the increase in time thereof are suppressed to the same extent as that of a new product, and the collection property is also secured, and the damage to the constituent fibers is suppressed to secure the strength.

However, since it is a regeneration method by heat melting or chemical reaction, it cannot be used under high temperature or in a chemically harsh environment, and its use is limited.

In addition, since the expensive special binder resin is applied by a special coating process from the beginning and separated by a special separation process at the time of regeneration, the manufacturing cost is not low and the price is not low. Not only this, but it was still possible to separate dust from the fiber during fiber regeneration, but it was still difficult to regenerate the binder resin itself by separating the dust from the binder resin. For this reason, practicality as a regeneration filter cloth for price fell.

In view of the above, the present invention can be used even under high temperature or chemically harsh environment without limiting the use while securing the same pressure loss and collection characteristics as the new filter cloth even after regeneration. An object of the present invention is to provide a regeneration method of a filter cloth and a low cost regeneration filter cloth thereby.

Patent Document 1: Japanese Unexamined Patent Publication No. 2003-103128

Patent Document 2: Japanese Unexamined Patent Publication No. 9-253432

Patent Document 3: Japanese Unexamined Patent Publication No. 2001-336054

In order to solve the said subject, this invention employs the following (1)-(12) means.

(1) The method for regenerating the filter cloth of the present invention includes at least a sea island treatment for breaking up the used filter cloth and a nonwoven fabric treatment for nonwoven fabrication of the fibers subjected to the sea island treatment.

Here, the sea island treatment of the present invention refers to a process of seaming the used filter cloth into each sea island single body. In addition, the nonwoven fabrication process of this invention refers to the process which arrange | positions mainly the fibers which were spun off, and shape | molds a nonwoven fabric to a desired shape by tangling, fixing, or bonding a fiber.

In such a case, dust is adhered between the fibers without fail, regardless of the surface layer portion or the inner portion of the constituent fibers before regeneration by forming the fiber unit by sea fiber.

Thereby, the dust adhered to the inside of the constituent fibers, which could not be separated by the above water washing method, is separated, and the pressure loss after the regeneration, the time rise and the collection properties can be obtained to the same level as the new filter cloth. In addition, the entanglement of the constituent fibers is not weakened by water washing, and the strength equivalent to that of the new filter cloth can be ensured.

In addition, the entanglement of the fibers is strengthened by the nonwoven fabric treatment, and the strength close to that of the new filter cloth can be obtained as compared with the water washing method.

In addition, the sea island treatment and the regeneration method by the nonwoven fabrication of the seaweed fiber can be reproduced without using a hot melt or chemically reactive resin such as the binder resin, so that it can be used even in a high temperature or chemically harsh environment, Applications such as filter cloth using the binder resin is not limited.

In addition, since there is no need for an expensive binder resin as described above, and there is no need for a special coating process, a highly practical regeneration is possible at a lower price than the filter cloth using the binder resin.

(2) Or the regeneration method of the filter cloth of the present invention may include a dust separation treatment for separating the dust adhered to the fiber obtained by the sea island treatment before the nonwoven fabrication treatment. That is, the method for regenerating the filter cloth, which comprises at least a sea island treatment for isolating the used filter cloth, a dust separation treatment for separating the dust adhered to the depleted fibers, and a nonwoven fabric treatment for nonwoven fabrication of the fiber subjected to the dust separation treatment. You may make it.

In this case, more dust can be isolate | separated by sea-separation and the dust separation process, and the outstanding air permeability and collection property can be obtained.

In addition, the entanglement of the sea island by the nonwoven fabric treatment becomes stronger, and the strength close to that of the new filter cloth can be obtained as compared with the water washing method.

(3) The regeneration method of the filter cloth of the present invention is preferably performed for efficient regeneration by the sea island treatment being passed through an automatic sea island.

In this case, the dust can be separated more easily by the mechanical automatic seam, and easy regeneration and further cheap regeneration are possible.

(4) In addition, the filter cloth used in the regeneration method of the filter cloth of the present invention is preferably used while adding a drug that decomposes all of dioxins and dioxins-derived substances, while suppressing adhesion of dioxins to the filter cloth.

Here, the dioxin origin substance of this invention means dioxin precursors, such as chlorophenol and chlorobenzene.

In this case, the agent added in the use state of the filter cloth before the use is completed decomposes the dioxins and dioxins origin material in the air containing dust to lower the concentration of dioxins themselves. As a result, the absolute number of dioxins in the dust in contact with the filter cloth is suppressed, and adhesion of the dioxins to the filter cloth is suppressed. In this way, by resolving the filter cloth which suppressed the adhesion of dioxins as a used filter cloth, a regenerated filter cloth having almost no adhesion of dioxins can be obtained.

Thereby, even the used filter cloth used under the dioxin atmosphere which was difficult to use conventionally can be used as a regeneration raw material. Further, the cost and effort required for the disposal procedure of the dioxins-attached filter cloth can be greatly reduced, resulting in a highly practical regeneration method at a low price.

(5) Moreover, in the regeneration method of the said filter cloth, it is preferable that the used filter cloth consists of PTFE fiber as a main component.

In this case, a regenerated filter cloth having excellent strength and filtration collection performance and excellent chemical resistance or heat resistance can be obtained.

(6) Or in the regeneration method of the filter cloth, the used filter cloth preferably comprises at least PTFE fibers and inorganic fibers.

In such a case, the regenerated filter cloth will contain the resolved inorganic fibers, thereby improving the collection performance. Moreover, the labor and cost for separating an inorganic fiber before seam treatment can be reduced, and the regeneration filter cloth containing an inorganic fiber can be obtained efficiently.

(7) The regenerated filter cloth of the present invention is characterized by comprising at least a collecting layer mainly composed of sea-island fibers obtained by decoupling the used filter cloth.

(8) In addition, the regenerated filter cloth may be provided with bubbles for fixing the collection layer. That is, it is good also as a regeneration filter cloth provided with the collection layer obtained by decomposing the used filter cloth and the bubble which fixes this collection layer.

In this case, the foam becomes more high strength, and the strength of entanglement of the constituent fibers can be maintained at a level equivalent to that of the new filter cloth even by backwashing in use.

(9) In addition, the regenerated filter cloth may be formed by collecting the auxiliary layer into the island fiber.

That is, a regenerated filter cloth having at least a trapping layer formed by mixing auxiliary fibers into fibers obtained by spinning the used filter cloth, or a trapping layer formed by mixing auxiliary fibers into fibers obtained by spinning the used filter cloth, and the collecting layer is fixed. It is good also as a regeneration filter cloth provided with the bubble to make at least.

In such a case, a regenerated filter cloth having high strength and elongation can be obtained by mixing auxiliary fibers.

(10) As the regenerated filter cloth, the collecting layer may be formed by nonwoven fabric of the fibers constituting the corresponding collecting layer itself.

That is, the collecting layer formed by decomposing the used filter cloth by nonwoven fabric, or the auxiliary layer may be mixed with the fiber obtained by decomposing the used filter cloth, and may be nonwoven fabric collected.

(11) In the above-mentioned regenerated filter cloth, it is preferable that the used filter cloth consists of PTFE fibers as a main component.

(12) In the regenerated filter cloth, it is preferable that the used filter cloth comprises at least PTFE fibers and inorganic fibers.

By adopting the means of (1) to (12), it is possible to secure pressure loss and collection properties equivalent to new filter cloths even after regeneration, and can be used even at high temperatures or in chemically harsh environments without being limited in use, and inexpensive. It is possible to obtain a highly practical method of reusing used filter cloth and a regenerated filter cloth at a price.

1 is a flowchart showing an embodiment of a method for regenerating a filter cloth of the present invention;

2 is an electron micrograph of a regenerated filter cloth according to an embodiment of the present invention, and

3 is an electron micrograph of a new filter cloth.

EMBODIMENT OF THE INVENTION Hereinafter, it demonstrates in detail based on the figure which showed the structure of this invention as an Example, and drawing substitute photograph. 1 is a flowchart of a reproducing method of an embodiment of the present invention, FIG. 2 is a 1000 times magnified electron microscope picture showing the state of fibers deemed by the sea island treatment of the present invention, and FIG. 3 is a comparative reference with FIG. It is a 1000 times magnification electron microscope picture showing the state of the fiber which was not subjected to sea island treatment.

The filter cloth and regenerated filter cloth used in the present invention are filter cloths used for powder collection. In particular, in the following examples, the incineration facilities in the incineration plant are fixed to a filter dust collector for collecting dust incinerators, and the dust containing harmful dusts such as dioxins, heavy metals, etc. in a high temperature environment, that is, 150 ° C. or higher is filtered as dust. To capture.

Hazardous dust refers to dust that is collected from dust collected by filtration as harmful in terms of environmental protection or health and hygiene.For example, a public agency is urged to regulate the amount of discharge into the environment and the intake of contents into the human body. This requires that shatterproof treatment be required.

In particular, dioxins in hazardous dust generally have high toxicity evaluations, and there are circumstances in which pollution monitoring or removal methods are specified, as well as environmental standards. Conventionally, all of the filter cloths used in the dioxin atmosphere are landfilled because effective reuse is difficult. On the other hand, applying the practical regeneration method of the filter cloth of the present invention as regeneration of the filter cloth which collected dust containing dioxins is not only preferable to the global environment, but also leads to prevention of accumulation of harmful substances in the human body, reduction of disposal cost and effort. do.

In addition, mercury, cadmium, lead, and the like, which are heavy metals among harmful dusts, also have problems in disposal methods and accumulation in the human body after surrounding the environment, and thus, the filter cloth of the present invention is also practical for these filter cloths with heavy metals. Application of the regeneration method is desirable for the global environment and also prevents the accumulation of harmful substances in the human body.

The filter cloth and the regenerated filter cloth of this embodiment include a trapping layer composed of at least PTFE fibers as a main component. PTFE fibers are suitable for filtration trapping layers because of their excellent chemical resistance, heat resistance, charge retention and strength. On the other hand, since incineration of PTFE fibers generates harmful gases including fluorine compounds such as hydrogen fluoride and carbon fluoride, and there is a problem of disposal similar to that of dioxins, PTFE fibers are particularly required to be recycled.

The filter cloth of the collection layer which consists of PTFE fibers can be used for high temperature dust collection which could not be used with the filter cloth which apply | coated the conventional hot melt binder resin by using it as a high temperature filter cloth of 150 degreeC or more of atmosphere.

The fiber of the collecting layer may be made of glass fiber, PPS, polyimide, metaaramid, or the like in addition to PTFE fiber, or may be mixed with PTFE fiber. In particular, the fibers of the collection layer after regeneration include a regenerated fiber as a main component, and it is preferable to mix one or two or more types of auxiliary fibers to assist the function (strength, elongation or collection performance) of the filter cloth.

It is preferable that the auxiliary fiber is a new (unused) fiber, and specifically, PTFE fibers suitable for the regenerated filter cloth or inorganic fibers such as silica, alumina, and glass fibers can be preferably used. In addition, the auxiliary fiber is preferably longer or thinner than other constituent fibers. The auxiliary fiber in the regeneration process of the used filter cloth is mix | blended by the "auxiliary fiber compounding process" mentioned later.

(Example of playback method)

As shown in Fig. 1, the regeneration method of the filter cloth of the present embodiment includes: 1. Addition of a medicament during the normal operation of the incinerator, the rise (start), and the fall (stop) to remove harmful dust components, and the adhesion or formation A chemical addition treatment to prevent the formation of the agent, 2. a water washing treatment to remove and collect the used filter cloth from the dust collector, and to wash and dry the filter cloth from which the metal and the like are separated, and 3. a sea island treatment to decompose the used filter cloth into each fiber. And 4. dust separation treatment for separating the dust adhered to the fibers which have been spun off, 5. nonwoven fabrication processing for nonwoven fabrication of the fibers subjected to the dust separation treatment, and 6. nonwoven fabrication of the nonwoven fabrics to the air bubbles by needle punching. Each process is demonstrated below which consists of the punching process to fix and the finishing process which reinforces and finishes the nonwoven fabric which carried this punching process from the surface, and prevents a fall of a fiber.

(1. Pharmaceutical addition processing)

The chemical | medical agent addition process is a process which adds a chemical | medical agent to the filter cloth which is in use during operation of a furnace and a dust collector. More specifically, the process includes a normal process of dispersing a chemical for preventing and removing harmful dust during normal operation of the incinerator, and a start-stop process of dispersing a harmful dust decomposition remover at the time of starting and stopping the operation of the incinerator. Thereby, the filter cloth can be used, reducing the absolute number of harmful dust in the air containing dust, and suppressing adhesion of the harmful dust to the filter cloth.

In this embodiment, the drug is a drug that decomposes both dioxins and dioxin-derived substances, and the used filter cloth obtained by the drug addition treatment is 3 ng (nanogram) -TEQ / g or less if the adhesion of harmful dust is, for example, dioxin. Is suppressed.

In addition, a chemical | medical agent addition process is a process required when the harmful dust containing a dioxin and a dioxin origin substance generate | occur | produces, and is unnecessary when these harmful dust do not generate | occur | produce.

Steady-state treatment is the process of spraying the harmful dust generation | medical agent which is a chemical agent regularly from a cooling tower before a dust collector. This prevents the generation of harmful dust generated little by little during the operation of the incinerator, and also adsorbs and removes the harmful dust in the dust collector.

When the harmful dust generation agent is a gaseous or solid dioxin, activated carbon and calcite which adsorb the gaseous and solid dioxin are mainly composed of, for example, Ueda Sekitan Seijo Co., Ltd. CD (brand name) ”. "Kumakark" (trade name) manufactured by Yakusen Co., Ltd. may also be used. Scattered harmful dust generation agent forms a harmful dust removing layer having a thickness of several μm on the filter cloth in the dust collector to prevent the adhesion of the solid dioxin, the harmful dust to the filter cloth.

Treatment at start-up and stop-up is a process of spraying a harmful dust decomposition remover, which is a chemical, before the cooling tower, flue, and dust collector at the start-up and stop of the incinerator. As a result, the entire main path of the dust-containing air is used as the harmful dust decomposition removal layer to decompose harmful dust and its source material. Specifically, by spraying about 300 mg / Nm3, high concentrations of dioxins and dioxins-derived substances generated in the flue or dust collector are decomposed when the incinerator becomes 300 ° C or lower in atmosphere.

Here, the start and stop time of the incinerator means a part included in the operation of the incinerator and the dust collector. The specific time period refers to a device inspection which is usually performed every three months for a relatively large incineration facility, and an operation stop for every seven to ten days for a relatively small incineration facility.

Dioxin origin material refers to dioxin precursors such as chlorophenol and chlorobenzene. This dioxin precursor is a substance that is the source of secondary production of dioxins other than incinerators.

The harmful dust decomposition removal agent uses "Ashnight multi A (brand name)" by Gurida Kogyo Co., Ltd., for example. Scattered harmful dust decomposition remover decomposes dioxins, which are harmful dusts in gaseous and solid phases, while simultaneously decomposing dioxin-derived materials to prevent the formation of harmful dusts. This prevents the increase of dioxins in the dust-containing air and also lowers the concentrations of dioxins and dioxins heat source materials themselves. Then, these deposits and further adhesion to the filter cloth are prevented.

(2.water washing treatment)

The water washing process is a process in which the used filter cloth is removed from the dust collector and recovered, and after separating the metal or the like, the used filter cloth is put into the running water to wash off the easily separable dust. It is preferable to mix surfactant with flowing water, and to chemically adsorb and isolate dust. Specifically, water is washed with a double barrel rotary drum type water washing machine and dried.

The used filter cloth refers to a filter cloth which does not function as a filter cloth as it is fixed to the dust collector by continuously using the filter cloth fixed to the dust collector. Specifically, the dust in the incineration smoke is collected by filtration while backwashing with compressed air is appropriately performed. As a result, the solid dust is deposited to the inside of the filter cloth. Or 1cc / cm2 / sec or less, or operating pressure loss is 1800 Pa or more, clogging occurs at least in part, or surface or internal breakage or fiber collapse is visually confirmed, which causes problems in the collection function itself. I say filter cloth of the state. A problem with this collection function itself is a state in which at least a portion of the powder leakage has occurred and the outlet dust concentration at the time of operation is greatly deteriorated. For example, a part of the filter cloth that has been greatly increased by use is formed of a shape retaining metal (retainer). Looseness of fibers or looseness or cracks in the part of the filter cloth greatly reduced by use. In the high temperature dust collection by a dust collector, it becomes the filter cloth used by the continuous operation of about 5 months-about 5 years, and especially in the dust collection of incineration smoke of an incinerator, it becomes the filter cloth used by the operation of about 3 years-5 years.

Wet cleaning with such chemical separation has a higher degree of cleaning than backwashing in which compressed air is injected as it is fixed to the dust collector. In addition, the separation of dust by the sea island treatment becomes high efficiency by performing it before the sea island treatment described next. However, since it is difficult to apply sufficient pressurization to parts other than the surface layer of the filter cloth, the dust or the like adhered to the internal constituent fibers cannot be completely washed off.

(3. sea island treatment)

The sea island treatment is to decompose the used filter cloth into each fiber to separate the dust sandwiched between the fibers in the constituent fiber, and to impart the physical pressure, shock and vibration during the sea fiber to electrostatically attach to each fiber. It is the process of separating dust. As a result, a high-performance regenerated filter cloth can be obtained at a simple and low price, and practical regeneration is possible. In this embodiment, the sea island processing is performed by passing through an automatic sea island.

An automatic sea island means a sea island that performs dismantling of fibers automatically by a power other than manual, except for sea islands which are only manually performed. Specifically, the transfer of the filter cloth before the sea island to the sea island and the sea island of the conveyed fiber are successively achieved by power other than manual or by power other than manual and manual. For example, each disintegration fiber having a fiber length of 10 mm to 50 mm, and preferably 20 mm to 40 mm is obtained by repeatedly passing through the automatic sea island by using a dry automatic sea island such as a comminr roll type until the bundle of fibers disappears. The comingro roll can use arbitrary things, such as a blade roll and a ganetrol.

At the time of this island-in-the-sea processing, you may add the bag which becomes an auxiliary fiber mix | blended in the auxiliary fiber compounding process mentioned later, and may perform a sea-island process and an auxiliary fiber compounding process simultaneously.

(4. Dust Separation Treatment)

The dust separation treatment is to separate dust adhered to each fiber after seam using a known dust separator. Known dust separators include, for example, "Micron Separator (trademark) (MS-1)" manufactured by Hosokawa Micron Co., Ltd., "Wool Cleaner" manufactured by Osaka Kikoku Co., Ltd., "Binder" manufactured by Ikekami Kikai Co., Ltd. Remover ”may be used, as well as a dry separation device such as a separation method using a punching metal or an air flow separation method, as well as a wet separation device using a water washing machine used in the water washing treatment. By separating the fibers after seam further, the dust dust adhering to the fiber unit can be separated with high efficiency. Thereby, it accumulates even inside the filter cloth by use, and isolate | separates the fine dust which cannot be removed by back washing or the conventional regeneration by water washing. In addition, the dust separation process may be water washing.

(5.Nonwoven Fabric Treatment)

The nonwoven fabrication process consists of an auxiliary fiber compounding step of blending auxiliary fibers with a number of fibers that have been spun off, and a lapform step of molding each of these fibers as a collecting layer of a regenerated filter cloth.

The auxiliary fiber compounding step is a step of blending fibers longer than each fiber after seam to strengthen the entanglement of each fiber after nonwoven fabric and to increase the strength and elongation of the regenerated collecting layer. This is a step optionally added depending on the use of the filter cloth after regeneration. Specifically, fiber lengths of 50 mm to 70 mm and auxiliary fibers having a diameter of 5 m to 20 m are added uniformly at a weight ratio of 20% to 70%, preferably 30% to 60%.

In this embodiment, the raw material of the auxiliary fiber is the same PTFE fiber as the collecting layer before regeneration, and a new fiber which is not used as a filter cloth is used. In addition, the auxiliary fiber may be made of a material different from the collecting layer, for example, inorganic fibers (silica, alumina, glass fiber, etc.) having a smaller fiber diameter than PTFE in a range suitable for the purpose of use. By this auxiliary fiber compounding process, the entanglement of the collection layer after regeneration becomes stronger. Moreover, by mixing glass fibers, the electrostatic effect is increased, and the collection efficiency after regeneration is increased.

The fineness of the auxiliary fiber is preferably 1dtex to 15dtex, or 3dtex to 10dtex. Auxiliary fibers of less than 1 dtex of fineness are difficult to obtain, and auxiliary fibers of 15 dtex or more of fineness increase in pressure loss, and by mixing auxiliary fibers having a small fiber diameter, the average fiber diameter of the entire collection layer is reduced and the pressure loss is lowered. .

The lap-form step is a step of forming (foaming) the desired fiber into a desired shape in order to arrange the unfinished fibers together with the auxiliary fibers as a collection layer after regeneration. The desired shape is a shape arranged and functioning as a collecting layer such as a plate shape, a web shape, a sheet shape, and the like. A well-known molding process, such as papermaking, can be used, in addition to a card type which is compressed into a sheet form by a compression roll and overlapped, and an airlay type which is formed by sucking with air. At the time of shaping | molding, you may add an oil agent etc. in order to suppress static electricity and a friction.

(6. Punching treatment)

A punching process is a process of fixing the collection layer which consists of the shaping | molding fiber group, and the bubble which raises intensity | strength and elongation along the said collection layer by needle punching. Alternatively, the needle punching process is performed by collecting a collection layer made of a group of fibers molded into a mold without bubbles or the like as necessary. Needle punching strengthens the entanglement of the fibers constituting the fiber group. Moreover, when punching process is performed along a bubble, intensity | strength and elongation will increase rapidly.

It is preferable that a bubble is made from PTFE which is the same material as a collection layer. If it is made of PTFE, it is excellent in heat resistance and chemical resistance, and becomes high purity even after regeneration. In addition, if other materials or other materials are mixed, the required strength can be secured while being inexpensive. Moreover, it is preferable that it is strength 100N / cm width or more and elongation 40% or less.

(7. finishing)

A finishing process is a process which fixes the form of the nonwoven fabric regeneration filter cloth, and is arbitrarily performed as needed. Specifically, it consists of the resin processing process of processing a surface with resin, and the heat processing process of heat processing.

The resin processing step is an arbitrary step of adhering the resin to the surface of the molded collection layer to prevent each fiber from falling off and oscillating from the collection layer after regeneration. Adhesion processing is by well-known means, such as spray coating and application | coating, in addition to the dipping immersed in liquid resin.

The heat treatment step is a step of performing a heat treatment at 200 ° C. to 330 ° C. in order to stabilize the shape of the regenerated filter cloth, and is optionally performed depending on the use such as for high temperature. Thereby, the collapse of a fiber when the regeneration filter cloth is used at 150 degreeC or more high temperature can be prevented.

(Specification of result)

Hereinafter, the regeneration filter cloth of the present invention regenerated by the regeneration method is identified. The regenerated filter cloth of the present invention includes at least a collecting layer obtained by decomposing the used filter cloth. Moreover, you may provide the collection layer obtained by decomposing the used filter cloth, and the bubble which fixes this collection layer at least.

The used filter cloth comprises at least PTFE fibers. The PTFE fibers are preferably made of the main component of the used filter cloth. Or at least inorganic fibers as well as PTFE fibers.

It is preferable that a collection layer is made by nonwoven fabric of the fiber which comprises a collection layer. The fibers constituting the collecting layer itself are mainly composed of seaweed fibers obtained by isolating the used filter cloth. The fibers constituting the collecting layer may be made by mixing auxiliary fibers with the sea fiber.

Bubbles are fixed to the collecting layer as necessary in order to maintain the shape of the collecting layer, and to secure the strength and the elongation. It is not necessarily necessary when the necessary strength is obtained by incorporating auxiliary fibers into the collecting layer or by nonwoven fabric of the fibers constituting the collecting layer.

That is, the following two aspects are mentioned as a structural aspect of the regeneration filter cloth which can fully acquire strength, for example. It is a regenerated filter cloth which consists of a collection layer which mix | blended auxiliary fiber with the fiber obtained by decomposing a used filter cloth, and made it nonwoven, or a regenerated filter cloth which nonwoven fabrics the fiber obtained by decomposing a used filter cloth.

Moreover, as a structural aspect which can ensure more preferable strength, the regeneration filter cloth provided with the collection layer which mix | blended auxiliary fiber with the fiber obtained by decomposing the used filter cloth, and the bubble which fixes a collection layer is mentioned.

The regenerated filter cloth of the present invention is fibrillated substantially uniformly throughout the thickness direction as well as the surface layer of the collecting layer by dissolving once, and a relatively thick fibrillated layer is formed.

As shown in Fig. 2, the substantially uniform fibrillation refers to a state in which there are branches of up to 10 fibers per fiber between branches before the branching.

2 shows the state of the fiber fibrillated by sea island treatment in the regeneration method of the present invention, and is an enlarged 1000 times electron microscope photograph. For comparison, FIG. 3 shows a state of the fibrillated fiber without the seam treatment. It is a 1000 times magnification of electron microscope.

The regenerated filter cloth of the present invention regenerates the filter cloth with dust by use, and some dust remains even by the regeneration method of the present invention. Specifically, dust of about 1 g / m 2 or less and dust of at least several mg / m 2 or more remain in the collection layer of the regenerated filter cloth. Even if it remains, if the initial ventilation amount is about the same as that of a new filter cloth, there is no problem in practical use. In addition, dust is likely to accumulate inside by long-term use due to the residual of initial dust, and the increase of the air flow rate is slightly increased, but there is no problem in practical use as long as the initial airflow amount is equivalent to a new filter cloth. As shown in the test results shown in Table 1 below, 135 Pa after 8 hours of use is also a value that can withstand practically enough.

In the regenerated filter cloth of the present invention, fibers obtained by sea fiber have a fiber length of 20 mm to 40 mm and a length of 50 mm or less. This is a mechanical limitation by passing through an automatic islander.

The density amount of the filter cloth (density of the whole filter cloth composed of bubbles and collecting layers) is about 300 g / m 2 to 1000 g / m 2 (particularly, 400 g / m 2 or more in the filter cloth having bubbles), preferably 600 g / m 2 to 800 g. / ㎡.

In the regenerated filter cloth of the present embodiment, the island fiber is roughly uniformly fibrillated as shown in FIG. The fibrillated seaweed fibers are then nonwoven to obtain the required collection rate even at a density of about 400 g / m 2. As a result, a large amount of recycled fibers can be obtained for a small amount of raw fibers, and a very low cost recycled fiber can be obtained by reducing the cost of the raw materials.

On the other hand, if the collection layer has a density of about 500 g / m 2 or more, more preferably 700 g / m 2 or more, it is possible to obtain high-density regenerated fibers by high-density, uniformly fibrillated fibers, and fine particle diameters that have not been previously collected. Dust can also be collected. Alternatively, even if the thickness of the collecting layer is made relatively thin, a high collection rate can be ensured as it is while the pressure loss is suppressed. As a result, an inexpensive regenerated filter cloth can be obtained.

In addition, the fibrillated portion of the island fiber is very thin with respect to the fiber body portion. For this reason, the pressure loss of a fibrillated part becomes below a measurement error, and collection efficiency becomes high compared with the collection layer which consists only of the fiber which is not fibrillated.

Since the regenerated filter cloth of this embodiment is fibrillated substantially uniformly in the thickness direction as well as the surface layer of the collection layer, for example, a single layer is not formed in the fibrillated layer of the front and back, and the two layers between the fibrillated layers of the front and back are not formed. The inertia of the air passing through vi) does not reduce the collection efficiency. For this reason, dust can be reliably collected and the collection efficiency is excellent.

The present invention is not limited to the above embodiment, including the specific configuration, machine, and method of each part, and at least if it has sea island treatment (preferably with sea island treatment and nonwoven fabric treatment), for example, the drug of the above embodiment. Each of the addition treatment, the water washing treatment, the dust separation treatment, the punching treatment and the finishing treatment is arbitrarily selected according to the use of the filter cloth, and included in each treatment step of the regeneration method as necessary. Similarly, other treatments are included depending on the use of the regenerated filter cloth. In addition, various modifications and combinations of the various processes are possible without departing from the spirit of the present invention.

(Comparative test)

The following comparative test was done about Example 1 of this invention. A comparative object is a comparative example which performed only the water washing process among the new filter cloth and the regeneration method of Example 1.

Example 1

As Example 1 of this invention used for a comparative test, it collect | recovered after operating for 6 months with the TQPJ type | mold dust collector made by Hokokawa Micron Co., Ltd. BF-800 made from Fujiko, the filter cloth which consists of a PTFE fiber in both a collection layer and a bubble. After washing with water in a washing machine and drying it (water washing treatment), it was made by Fujiko Dry Co., Ltd., a dry automatic sewing machine, which is then processed into fibers with a fiber length of 40 mm or less at 500 rpm, and treated with Hosokawa Micron. Dust separation (dust separation process) at 2100 rpm of rotor rotation by the micron separator (MS-1) made from Corporation | KK, and it wraps with the commercially available roller card (non-woven fabrication process), and the strength is 750N / 5cm width, The bubble of 25% elongation was fixed by needle punching (punching process), and the thing shape | molded by the filter cloth of thickness 1.3mm is used.

(Comparative Example 1 (new filter cloth))

Fujiko BF-800 is used as a new filter cloth of Comparative Example 1.

(Comparative Example 2 (regeneration filter cloth by the water washing method))

As Comparative Example 2, a filter cloth which was not subjected to the sea island treatment, the subsequent dust separation treatment, the nonwoven fabrication treatment, the punching treatment, and the finishing treatment of Example 1 was used.

(Contents of comparison test and measurement result)

As a comparative test, the initial ventilation, final ventilation, and outlet dust concentration were measured based on German VDI3926. As measurement conditions, JIS 10 type (fly ash) was used for filtration rate 3.0m / min, inlet dust concentration 5.0g / m <3>, and dust. In addition, when the air permeability reached 1000 Pa, back washing was performed by injection of compressed air for several hours, and eight hours were continuously operated as the test time.

Initial ventilation is the ventilation immediately after the start of the test. The final aeration is after 8 hours of test time. The outlet dust concentration is a value obtained by dividing the total amount of dust obtained at the outlet by eight hours of operation by the total amount of air for eight hours. The results are shown in Table 1 below.

According to the measurement result shown in the said Table 1, the regeneration filter cloth of Example 1 which concerns on this invention is 70 Pa of initial stage ventilation, and shows the same pressure loss as the new filter cloth (70 Pa). This means that by the regeneration method of the present invention, the dust is separated to a degree equivalent to that of the new filter cloth, and a practical regeneration filter cloth can be obtained. In addition, much more dust is separated compared with the regeneration filter cloth 106Pa of the comparative example by water washing only.

Moreover, the pressure loss after 8 hours of use is 135 Pa, which is slightly larger in value than the new filter cloth 122 Pa, but practically, clogging is not easy, and the service life is about the same as that of the new filter cloth. In addition, compared with the regenerated filter cloth 302Pa of the comparative example, Example 1 of the present invention is not much clogged, and has a long life as a regenerated filter cloth.

According to the measurement result shown in Table 1, Example 1 is 0.812 mg / m <3> of outlet dust density | concentration, and shows the collection property higher than the comparative example (2.15 mg / m <3>) as well as a new filter cloth (1.173 mg / m <3>). This is considered to be due to fibrillation of the fiber as shown in FIG. 2 by sea islands.

The filter cloth regeneration method and regenerated filter cloth of the present invention are used, for example, in a filter dust collector such as a waste incinerator. In addition, it is connected to a crusher, classifier, dryer, paint booth, asphalt plant, building, and various furnaces, and can be applied to various filter dust collection including air transportation and powder production.

Claims (12)

And at least a nonwoven fabrication process for nonwoven fabricating the fibers subjected to the seaweed treatment. The method of claim 1, And a dust separation treatment for separating the dust adhered to the fibers obtained by the sea island treatment before the nonwoven fabrication process. The method according to claim 1 or 2, The sea island treatment is carried out by passing through an automatic sea island. The method according to any one of claims 1 to 3, The used filter cloth is used while adding a chemical which decomposes a dioxin and a dioxin origin material together, and suppressing adhesion of a dioxin to the filter cloth. The method according to any one of claims 1 to 4, The used filter cloth is made of PTFE fibers as a main component. The method according to any one of claims 1 to 5, The used filter cloth comprises at least PTFE fibers and inorganic fibers. A regenerated filter cloth comprising at least a collecting layer mainly composed of seaweed fibers obtained by isolating the used filter cloth. The method of claim 7, wherein A regenerated filter cloth comprising a bubble for fixing a collecting layer. The method according to claim 7 or 8, The collecting layer is a regenerated filter fabric, characterized in that the auxiliary fiber is mixed with the sea fiber. The method according to any one of claims 7 to 9, The collecting layer is a regenerated filter cloth, characterized in that the fiber constituting itself is made by non-woven fabric. The method according to any one of claims 7 to 10, The used filter cloth is a recycled filter cloth, characterized in that consisting of PTFE fibers as a main component. The method according to any one of claims 7 to 11, The used filter cloth is a recycled filter cloth comprising at least PTFE fibers and inorganic fibers.

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