JP3687765B2 - Felt for high temperature filtration dust collection and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a felt fabric by a needle felt method using a fiber of polyphenylene sulfide (hereinafter referred to as “PPS”) fiber and a coarse cloth thereof, and particularly at high temperatures (160 to 210 ° C.), acidic gas, oxidizing dust An object of the present invention is to provide a filter cloth for collecting dust that is optimal for bag filters used under severe atmospheric conditions such as alkali agents and high moisture content.
[0002]
[Prior art]
Conventionally, exhaust gas generated from coal fired boilers, municipal waste incinerators, industrial waste incinerators, metal melting / calcining furnaces, etc. contains a large amount of harmful substances and dust, but they are removed as close as possible. To do is a very important issue.
There are various methods for collecting exhaust gas, but recently, the dust collection method using a bag filter has been adopted to improve dust collection efficiency, reduce dioxins, and efficiently remove other harmful gas components. It has become mainstream.
[0003]
The bag filter filtration type dust collection method uses a filter cloth sewn in a cylindrical shape or an envelope shape, and an appropriate fiber material is selected for the filter cloth depending on the exhaust gas component conditions to be filtered.
[0004]
The gas temperature at the dust collector inlet in the exhaust gas dust collection such as the above-described boiler and incinerator is generally 130 to 250 ° C. When the temperature is 130 ° C. or lower, general-purpose fibers such as polyester and acrylic are used as filter cloth materials. When the temperature is 130 ° C. or higher, so-called heat-resistant fibers are used, but among them, the PPS fiber of the present invention is used continuously. Since the temperature is 190 ° C. and the acid / alkali resistance is excellent, the exhaust gas filtration has been widely used in recent years.
[0005]
PPS fiber has both general heat resistance and chemical resistance, but also has general fiber characteristics. Therefore, PPS fiber has processability that allows no problems when processing into fiber products such as felt and woven fabric. Filter cloths in the form of felts and fabrics are widely used.
[0006]
Even if the exhaust gas temperature of the bag filter that passes through the filter cloth and collects the exhaust gas is always operated at 180 ° C., the boiler and the incinerator may be heated abnormally and reach around 210 ° C.
In general, the upper limit of this abnormal temperature is called the peak temperature. Moreover, it is generally said that the total time required for the peak temperature is equivalent to 5% of the total operating time of the filter cloth.
[0007]
2. Description of the Related Art In recent years, pulse jet type dust collection, in which dust accumulated on the surface of a filter cloth is removed with pulsed pressure air, has become mainstream. This equipment consists of a cylindrical retainer inserted into a cylindrical retainer made of thick wire, and this type of equipment that collects dust more efficiently and tends to continue increasing It is in.
[0008]
The filter cloth used in this kind of pulse jet type dust collector is several minutes to several tens of minutes for dedusting under intense atmospheric conditions such as high-temperature acid gas, oxidizing dust, and alkali as a neutralizing agent. It receives the action of being expanded by pulse air once.
Although these actions continue to be applied for a long period of time, the cloth must have enough strength to withstand it, and it must maintain a margin enough to operate in the opposite direction to that during the filtering action by pulse air. That is, if the filter cloth contracts while the filter cloth is filtering, the dust removal effect by pulsed air cannot be expected.
[0009]
The conventional needle felt filter cloth using PPS fibers has a large shrinkage at an atmospheric temperature of 190 ° C or higher, so that the dedusting action in the pulse jet type dust collector does not work, so the pressure loss value rises. There was a problem that could cause a filter cloth breakage accident.
[0010]
[Problems to be solved by the invention]
The present invention is for solving the above-mentioned problems of the prior art, and it is 24, in terms of felt strength and felt shrinkage up to a cumulative 2,100 hours even if the dust collector inlet temperature is a peak temperature up to 210 ° C. An object of the present invention is to provide a felt fabric for high-temperature filtration capable of continuous operation for 000 hours (3 years).
[0011]
[Means for Solving the Problems]
That is, the present invention provides a sheet-like laminate comprising a web layer on both sides of a base fabric, and the base fabric and the web layer entangled, wherein the base fabric is polyphenylene sulfide and / or polytetrafluoroethylene. And the web layer is composed of polyphenylene sulfide fibers, and the laminate has a dry heat shrinkage at 210 ° C. of 1.5% or less and a strong retention rate (210 ° C. × 2100 hours) of 80% or more. Felt for high temperature filtration dust collection, characterized by
The polyphenylene sulfide fiber constituting the web layer has a dry heat shrinkage rate of 4% or less, an oil agent adhesion rate of 0.3 to 0.5 owf, a strength of 3.0 g / d or more, and a breaking elongation of 35 to 45%. The felt for high temperature filtration dust collection according to claim 1,
Claim 1, wherein the high-temperature filtration dust collecting felt basis weight of the laminate 350~750g / m ² thickness, characterized in that a 1.5 to 3.0 mm,
A high-temperature filtration characterized in that a card web made of polyphenylene sulfide fiber is heat-set at 160 to 230 ° C., then cooled under no tension, and then wound on the both sides of the base fabric obtained by winding the card web. It is a manufacturing method of the felt for dust collection.
The needle felt filter cloth of the present invention is a sheet-like laminate by a needle punch method using PPS short fibers quality-controlled within a specific range for the web and PPS fibers and / or polytetrafluoroethylene for the base cloth. The above object is achieved by creating a body and compressing and heat-treating it under specific conditions to form a dense filter cloth structure.
[0012]
In a preferred embodiment, the needle felt filter cloth of the present invention has a purpose of 350 to 750 g / m ² and a thickness of 1.5 to 3.0 mm.
[0013]
The base fabric used in the present invention is preferably produced from PPS fibers and / or polytetrafluoroethylene fibers. The yarn constituting the base fabric can be either spun yarn made from fiber or filament yarn.
These yarns are used to weave a coarse base fabric.
[0014]
The PPS used in the present invention is formed of a polymer / or a derivative thereof having a repeating unit of (—C ₆ H ₄ —S—).
[0015]
The PPS is usually prepared by dissolving sodium sulfide in a polar solvent such as N-methylpyrrolidone, adding a polymerization accelerator, spinning the polymer obtained by the polycondensation reaction with paradichlorobenzene by the melt spinning method, and drawing. Obtained.
[0016]
The polytetrafluoroethylene used in the present invention is formed of a polymer having a repeating unit of (—CF ₂ —CF ₂ —) and / or a derivative thereof.
[0017]
The base fabric used in the present invention achieves the purpose of improving the strength and dimensional stability of the needle felt fabric without significantly impairing the air permeability of the obtained needle felt fabric. For this purpose, the PPS fiber and / or polytetrafluoroethylene fiber monofilament yarn, multifilament yarn or spun yarn is used alone or in combination, and is preferably formed by weaving into plain weave, twill weave, mocleno weave, leno weave, etc. Is done. There is no particular limitation on the fineness and woven density of the fibers used.
[0018]
The laminate of the present invention has a web on both sides of a base fabric, and in the sheet-like laminate in which the base fabric and the web are entangled, the dry heat shrinkage rate of the laminate at 210 ° C. is 1. .5% or less.
[0019]
In order to achieve this object, it has been found that the characteristic values (dry heat shrinkage rate, oil agent adhesion rate, strength, elongation at break) of the individual polyphenylene sulfide fibers constituting the web have a great influence.
[0020]
At the time of web formation, PPS fibers are dispersed in a sheet shape, but if the dispersion exceeds the limit in the individual fiber characteristic values, there is a possibility that heat shrinkage stress is inherent in the local part of the web sheet. Become.
[0021]
The greatest factor that affects the heat shrinkage rate of the final felt is the heat treatment step performed after the fiber entanglement step with the web and base fabric constituting the felt.
[0022]
The PPS fiber constituting the web has a dry heat shrinkage rate of 4% or less, an oil agent adhesion rate of 0.3 to 0.5 owf, preferably 0.39 to 0.41 owf, a strength of 3 g / d or less, a breaking strength of 35 to 45%, Preferably, the quality should be controlled to 36 to 44%.
[0023]
When the PPS fiber of the web structure has a large variation in dry heat shrinkage of more than 4% and a mixture of 4% or less, the final finished 150 cm width felt is partially 140 cm wide. The point of becomes obvious.
[0024]
In the sheet-like laminate having the web made of the above-described PPS fibers on both sides of the above-mentioned base fabric, and the base fabric and the web being entangled, dry heat treatment is performed after the fiber entanglement step. Do. In this step, heat treatment is performed while pressurizing with dry heat of 160 to 230 ° C., preferably 190 to 220 ° C. By this heat treatment, the laminate is consolidated to a thickness of around 2 mm, but the heated sheet-like laminate is once stored in a storage tank (scraper) under no tension. The sheet-like laminate is relaxed in strain, and structural strain accumulated during processing so far is removed.
[0025]
【The invention's effect】
According to the present invention, it is possible to provide a felt for high-temperature filtration dust collection that enables continuous operation for a long period of 3 years even when the dust collector inlet temperature is a peak temperature up to 210 ° C.

Claims (3)

In a sheet-like laminate having a web layer on both sides of a base fabric, and the base fabric and the web layer entangled by needle punching , the base fabric is composed of polyphenylene sulfide and / or polytetrafluoroethylene And the web layer is composed of polyphenylene sulfide fibers having a dry heat shrinkage rate of 4% or less, an oil agent adhesion rate of 0.3 to 0.5 owf, a strength of 3.0 g / d or more, and a breaking elongation of 35 to 45% , A felt for high temperature filtration dust collection, wherein the laminate has a dry heat shrinkage at 210 ° C of 1.5% or less and a strong retention rate (210 ° C x 2100 hours) of 80% or more.   2. The felt for high temperature filtration dust collection according to claim 1, wherein the weight of the laminate is 350 to 750 g / m @ 2 and the thickness is 1.5 to 3.0 mm. A card web made of polyphenylene sulfide fiber having a dry heat shrinkage rate of 4% or less, an oil agent adhesion rate of 0.3 to 0.5 owf, a strength of 3.0 g / d or more and a breaking elongation of 35 to 45% is heat set at 160 to 230 ° C. Then, a method for producing a felt for high temperature filtration dust collection, characterized in that a low shrinkage web obtained by winding after cooling under no tension is disposed on both sides of a base fabric.