JP2002301318A - Filter cloth for device for removing particulate in exhaust gas and catalyst element made of the filter cloth - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst filter cloth made of a glass cloth which can substantially remove particulates in the exhaust gas from a car driven by an inner combustion engine, particularly particulates having <=2.5 μm particle size without generating an irregular flow by a method for imparting heat resistance to glass which is easily operated. SOLUTION: The filter cloth constituting a catalyst element to be used for the device for removing particulates in the exhaust gas from the car driven by the inner combustion engine is prepared by heat cleaning a glass cloth near the glass transition point and depositing a metal catalyst thereon. The filter cloth preferably consists of a laminated body produced by laminating a plurality of layers each layer consisting of a combination of at least three ripstop cloth sheets carrying the metal catalyst and one plain weave fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to exhaust gas containing suspended particulates (hereinafter referred to as "exhaust particulates") emitted from automobiles which are sources of exhaust gas movement, particularly automobiles driven by an internal combustion engine using fuel such as gasoline, diesel light oil, LPG, etc. The present invention relates to a catalyst element used in an exhaust gas particulate removing device for removing methane and a filter cloth for the element. In particular, the present invention relates to a catalyst element for removing fine particles of exhaust gas which is suitable for use in a diesel particulate filter (DPF) mounted on a diesel engine vehicle, and a filter cloth therefor.

[0002]

2. Description of the Related Art Gasoline fuel, diesel light oil fuel, L
Exhaust gas from PG fueled vehicles is mainly composed of nitrogen oxides (NOx) such as nitric oxide and nitrogen dioxide, and suspended particulate matter (S
It contains air pollutants such as PM). In particular, from diesel engine vehicles, along with nitrogen oxides, which are about three times as large as the amount discharged from gasoline vehicles, etc., a large amount of fine particles (DEP) with a particle count of 2.5 μm or less, which is incomparable with that, is produced. Excretion causes health problems such as respiratory illness and asthma, and has become a social problem. But
Although emission controls are being implemented for nitrogen oxides from any source and measures are being taken, particulate matter is still inadequate, as most diesel engine vehicles have no emission controls. It remains. In particular, an environmental standard as a basis for regulating diesel engine exhaust particulate matter (DEP) is also referred to as a “PM2.5 environmental standard” and is an important concern. DEP includes not only primary particles but also secondary particles, such as black smoke or soot (black amorphous carbon), road dust, sulfur oxides (SOx), and carcinogenic hydrocarbons such as benzopyrene. Therefore, it is easier to enter the airways and lungs of the human body and is a troublesome entity.

[0003] As a method for removing both nitrogen oxides and suspended particulate matter, conventionally, a denitration device (nitrogen oxide removal device) including a denitration catalyst and a dust collector such as a bag filter or an electric dust collector are provided in parallel. The method is general. Regarding the latter, various bag filters of a dust collection system for filtering and separating high concentration dusts have been developed. For diesel vehicles, a type of diesel dust removing device (D) including a particulate matter filtering filter capable of driving the removal of particulate matter more strongly and a regeneration device for preventing clogging is provided.
PF) has been developed and various types of devices have been put into practical use. However, all of them have technical problems, and at present, a definitive device capable of quantitatively controlling and taking measures against diesel exhaust particulate (DEP) has not yet been developed. For example, those that are not compatible with other companies' diesel vehicles and are too expensive, those that do not exhibit sufficient performance unless the continuous running time and speed are over a certain level, and those that do not provide sufficient performance unless the sulfur content in light oil is reduced. There are none. Therefore, the emergence of a practical diesel particulate matter removal device (DPF) for diesel vehicles that enables quantitative regulation and countermeasures of DEP is urgently expected.

A device for removing particulates from exhaust gas of an internal combustion engine driven vehicle including a diesel engine vehicle includes a catalyst element (structure) obtained by processing a burner and a catalyst filter,
It is mainly composed of heat exchangers. As the catalyst element, for example, a net-shaped glass cloth is used as a carrier, and various types of structures such as a honeycomb structure, a porous structure, and a net-shaped structure having a catalyst supported thereon are variously known. I have. In addition, a glass cloth carrier of plain weave, twill weave, or satin weave has been invented instead of a general net-like cloth (Japanese Patent Application Laid-Open No. 2001-9225).
A).

[0005]

A glass cloth used as a catalyst element in an exhaust gas particulate removing apparatus of the type described above has conventionally had a heat resistance and a direct catalyst that can withstand high temperatures in a catalytic reaction during the operation of the removing apparatus. To obtain an acceptable surface, an acid leaching or leaching process, called "silica treatment", has been used. For example, E-glass or S-glass is subjected to an acid treatment to remove components that dissolve in the acid to form a silica-rich glass having a silica content of 90% or more, so that the heat resistance is 650 ° C.
The temperature is raised to 800-900 ° C from below,
The catalyst could be easily supported on the glass cloth surface.

However, this chemical leaching method requires a long time of many days with a heated acid solution, and the obtained glass cloth becomes porous and has surface irregularities. Therefore, it is necessary to smooth the surface by shrinkage treatment. As a result, the strength increased but the length of the glass cloth shrank by about two thirds. In addition, it was necessary to treat the acid waste liquid after use. Therefore, the leaching method of the glass cloth requires a long time, complicated work and cost, and there are economical and method defects as a whole due to material loss due to shrinkage.

The present invention overcomes the drawbacks of the method for leaching glass cloth with an acid, so that
A method of obtaining a glass cloth that has heat resistance of about 0 ° C. to 900 ° C., does not fuse and bond with E glass or the like even when low-melting fly ash coexists, and maintains smoothness even at high temperatures. I have been conducting intensive research in search of economical methods that can be put to practical use. As a result, it has been found that the above problem can be solved at a stroke by heat cleaning the glass cloth at a temperature near the glass transition point, instead of the chemical treatment method. The present inventors have found that an excellent filter effect can be achieved by employing a special woven fabric that can be prevented, and completed the present invention.

Accordingly, an object of the present invention is to replace the acid leaching method of glass cloth with a simple and easy heat treatment treatment at the glass fiber filament stage of glass cloth to remove fine particles of exhaust gas, especially diesel fine particles of diesel exhaust gas, under high temperature conditions. Another object of the present invention is to provide a low-cost filter cloth having a high-performance filter effect that can be substantially completely processed (about 90%). A filter capable of effectively filtering, burning, removing and purifying exhaust gas particulates from gasoline and LPG fueled vehicles as well as diesel fueled vehicles by means of an economical treatment method such as acid leaching method with no loss of glass cloth without drift. Another object of the present invention is to provide a cloth and a catalyst element for an exhaust gas particulate removing apparatus using the cloth.

[0009]

According to the present invention, there is provided an exhaust gas particulate removing apparatus comprising a glass cloth laminate formed by laminating a plurality of layers each preferably comprising a combination of two types of glass cloth. A filter cloth, wherein the glass cloth of each layer is a glass-rich glass cloth containing 90% or more of a quartz content obtained by heat cleaning near the glass transition point after weaving from a glass fiber filament as a carrier. It is characterized by directly supporting a metal catalyst.

That is, the present invention provides (1) a laminated filter cloth for a catalyst element installed in an exhaust gas particulate removing apparatus, comprising a plurality of layers in which two types of glass cloth are combined in pairs. A filter cloth, wherein the glass cloth of each layer is rich in quartz containing 90% or more of a quartz content, and a metal catalyst is supported on the glass cloth; (2) the glass cloth of each layer is E glass fiber A glass cloth or a silica cloth woven by using a filament or an S glass fiber filament, wherein the filter cloth according to the above (1), wherein the glass cloth of each layer is an E glass fiber filament or an S glass fiber filament. Glass cloth or silica cloth woven using (4) The filter cloth according to (1) or (2), wherein the metal catalyst is a metal oxide catalyst and / or a reduced metal catalyst. (1) The filter cloth according to the above (1) or (2), wherein the metal catalyst is a platinum group metal catalyst or an activated catalyst. The filter cloth according to any one of the above (1) to (5), wherein the cloth pair comprises a combination of at least three ripstop fabrics and one plain woven fabric, (7) the glass fiber filament is (8) The filter cloth according to (2) or (3), which has a monofilament diameter of 3 to 15 μm. (9) The filter cloth according to the above (4), wherein metal catalysts are alternately arranged, and (9) a platinum group metal catalyst is supported on the surface of the glass filament carrier via a chromate layer. (5) The filter cloth according to (5), (10) the catalyst filter cloth according to (5), wherein the platinum group metal catalyst is a platinum catalyst or a platinum-palladium-rhodium-based three-way catalyst, (11) the (1) (10) A catalyst element for an exhaust gas particulate removing device comprising the filter cloth according to any one of (1) to (10), (12) The above (11) used in an exhaust gas particulate removing device mounted on an automobile driven by an internal combustion engine. (13) The catalyst element according to (11) or (12), which is used in a diesel dust removal device mounted on a diesel engine vehicle. (12) or (13), wherein the catalyst element and (14) are a foldable pleated structure in which exhaust gas particles are circulated in a through-flow in the filter cloth catalyst layer of the catalyst element and catalyzed at the same time. The catalyst element as described.

The glass cloth used in the present invention can be manufactured, for example, as follows. The glass cloth used as a raw material in the present invention is a quartz content obtained by heat-cleaning a glass cloth woven using a glass fiber filament such as a monofilament or a multifilament, preferably near the glass transition point.
% (% By weight) or more, is a glass cloth or a silica cloth composed of quartz-rich glass filaments. A metal catalyst is supported on the glass cloth or a quartz content of 90% obtained by heat-cleaning a glass fiber filament near a glass transition point.
(% By weight) Obtain a yarn composed of quartz-rich glass filaments containing at least (weight%), carry a metal catalyst on this, and weave the yarn carrying the metal catalyst to produce a glass cloth useful as a filter cloth You can also.
The glass transition point in the present invention may vary depending on the type of glass used and various heating conditions, but is usually about 330 to 480 ° C, but may be other values. The heating time also varies depending on the type of glass cloth and other heating conditions, and therefore cannot be specified unconditionally, but is generally about 1 day to 10 days. The weaving referred to in the present invention may be, for example, any of a woven fabric, a knitted fabric, a knitted fabric, and the like, and the woven fabric may be, for example, any of a plain weave, a twill weave, and a leno weave. The weaving method and the method of supporting the catalyst on the heat-cleaned glass cloth may be performed according to a known method.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A filter cloth and a catalyst element of the present invention will be described below. Before that, an exhaust gas particulate removing apparatus for an automobile driven by an internal combustion engine, which is an object of the present invention, will be described. One example is a removal device mainly composed of a gas heating chamber including a burner, a catalyst reaction chamber surrounded by a catalyst element (structure) incorporating a catalyst filter, and a heat exchanger. Attached near. In this case, the exhaust gas fine particles that have flowed out of the exhaust port of the car and flowed into the removal device are ignited by a burner,
The filter circulates through the filter while performing filtration and catalytic combustion with a catalytic filter, purifies and renders it harmless, enters the heat exchanger as clean hot air, and recovers heat.This has a structure that can save fuel. .

The filter cloth of the present invention comprises a plurality of layers formed by combining two types of glass cloth pairs, for example, 2 to 2 layers.
The glass cloth pair of each layer is composed of three to five ripstop woven glass cloths, and the other is one plain woven glass cloth. Each glass cloth is preliminarily heat-cleaned at a temperature near the glass transition point of the raw glass cloth,
It is composed of quartz-rich glass fiber filaments having a surface that is easily supported by the catalyst and has a quartz content of 90% or more.
It is a catalyst filament yarn supported by a metal catalyst. Glass fiber types that can be used for glass cloth are E,
C, S, AR, D glass and the like, and particularly preferred is E
Glass or S glass. In the case of E glass, the glass cloth is heat-cleaned at about 350 to 450 ° C., preferably around the glass transition point of about 400 ° C.

Among the glass cloth pairs of each layer, one of the ripstop fabrics is composed of 2400 to 7200 in which a multifilament yarn having a monofilament diameter of 3 to 15 μm is twisted.
The density of the warp and weft is around 14 / inch, for example, from a thin and a thick yarn consisting of 3 twists of 800 bundles, 9 twists of 800 bundles or 6 twists of 1200 bundles. Preferably, it is configured. Thick threads are inserted at regular intervals to prevent them from tearing long from small flaws. The weight of the plain weave cloth is 400-650g.
/ M ² is preferred. When the ripstop fabric is incorporated into the catalyst element of the exhaust gas particulate removal device,
It is located at the front stage where it first encounters the exhaust gas particulate stream.
When passing through the first layer of at least three ripstop fabrics and one plain woven fabric, about half of the exhaust gas particulates are removed by filtration and combustion, and in the next second layer, about half of them are further removed. In the third layer, about half is further removed, so that about 80 to 90% is cut and purified. In this case, it is preferable that each layer is provided with an oxidation catalyst layer and a reduction layer alternately. The ripstop fabric allows smooth flow of the exhaust gas particles without drifting and does not cause clogging.In addition, the catalyst is supported in the filament stage, so that the catalyst surface area extends over multiple layers of cloth. Since the filter cloth of the present invention is extremely large, the filter cloth of the present invention can exert a powerful filter effect that is much better than the conventional filter cloth. The glass cloth layer is clogged due to pressure loss and the like, even if a plurality of glass cloth layers are stacked, and a drift occurs. Therefore, the number of glass cloth layers is at most 3 to 4 layers, and preferably 2 to 3 layers.

A catalyst is carried on the quartz-rich glass cloth after the heat cleaning process. Various catalysts for removing exhaust gas fine particles have been established in the past, and such a known catalyst may be used in the present invention. For example, an oxidation catalyst or a reduction catalyst can be used. Examples of the oxidation catalyst include a platinum group metal catalyst. The platinum group catalyst is supported directly or via a chromate film layer. The platinum group metal catalyst is selected from ruthenium, rhodium, palladium, osmium, iridium, and platinum, and a platinum-based catalyst or a platinum-palladium-rhodium three-way catalyst is preferred. For the former, those known as platinum black, platinum sponge, platinum with platinum black and the like are used. In the latter, a glass cloth is immersed in a propylene glycol solution of platinum chloride, palladium chloride, and rhodium chloride, and then heated at a high temperature, for example, at 250 ° C. for 1 hour and
Heat treatment is performed at 50 ° C. for 1 hour, and further activated in a hydrogen reducing gas atmosphere. Examples of the chromate that may be interposed include chromates such as molybdenum, antimony, zinc, and barium.
It is desirable that the thickness be 2 μm or more. It never binds to the molten ash in the dust and has heat resistance. Further, it is preferable that a plurality of catalyst layers are stacked, and the oxidation catalyst and the reduction catalyst are alternately arranged. As the reduction catalyst, a known activated catalyst can be used. The glass cloth filter filters and collects the fine particles of the exhaust gas, while the platinum group catalyst promotes the oxidation and combustion of nitrogen oxides and soot contained in the catalyst and burns without clogging, The exhaust gas particles are rendered harmless, purified and removed.

When the filter cloth of the present invention is configured as a catalyst element (structure) of an exhaust gas particulate removing device, it is formed into a cylindrical shape as a whole as a pleated structure that is folded in a bellows shape, and is supported and incorporated by a retainer. . Exhaust gas particles flow in from the surface of the folded folds as a through flow and flow through 10 to 20 catalyst layers, so that a remarkably excellent filter effect is obtained as compared with the conventional parallel flow type filter. Can be
Therefore, it can be effectively used not only for gasoline vehicles and LPG vehicles, but also for diesel vehicles in which it is difficult to remove exhaust gas particulates.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 E Glass single fiber A filament having a diameter of 9 μm (ECG37 manufactured by Unitika Glass Fiber Co., Ltd.) was used.
The yarn was plied into a nine-ply yarn with no bundle. Then, the ripstop fabric was woven at a weave density of 14 yarns / 25 mm by using them for warp and weft. The above filaments were used to produce 1600 aligned yarns, which were used for warp and weft yarns to produce a 430 g / m ² plain woven fabric. The thus-prepared wrist-up glass cloth and plain-woven glass cloth were each heat-cleaned at 400 ° C. for 100 hours to remove organic substances such as starch and scale from the weaving. Next, a platinum black catalyst layer was applied to the glass cloth made of quartz rich filaments having a quartz content of 95% in this manner by a conventional method.
A uniform thickness of μm was applied. From the combination of the three ripstop cloths thus obtained and one of the latter plain weave cloths, they were superposed into one layer, and three layers were laminated to obtain a total of 12 glass cloths.

As a laboratory test for confirming the filter effect of the laminated filter cloth, the filter cloth was set in the middle of a closed container, and a heater was installed under the filter cloth. An experiment to examine the extent to which the blackness of dust in the first catalyst layer at the entrance and the last catalyst layer at the exit of the glass cloth is reduced by passing 1 g of the dust (fine particles of exhaust gas such as black smoke or soot) through the multilayer catalyst layer of the filter cloth by suction. Was done. Thereafter, the filter cloth was taken out, and the blackness of the filter cloth on the entrance side and the exit side was measured and compared. As a result, the black of the first black smoke was slightly left at the end, and about 80 to 90% of the black smoke was left. It was found that there was a dust removing effect, that is, a filter effect.

[0020]

The filter cloth or catalyst filter of the present invention is supported by a catalyst such as a platinum group catalyst using a quartz-rich glass cloth having a quartz content of 90% or more, which has been subjected to heat cleaning near the glass transition point, as a carrier. Preferably at least 3 ripstop fabrics
It is a laminate of two types of cross-combination layers, one sheet and one plain weave, and since it is composed of 10 to 20 multilayer catalyst layers in total, the catalyst surface area is extremely large, and therefore the dust removal effect by catalytic combustion is also high. Is big. Further, by forming the filter cloth as a catalyst element (structure) formed in a folded pleat shape, for example, the exhaust gas particulate matter can be filtered and collected as a through-flow without clogging, and at the same time, the catalyst can be combusted and removed. Therefore, it is possible to achieve an extremely excellent filter effect, which can purify and remove fine particles such as diesel exhaust particulate matter. The heat resistance and the catalyst carrying capacity of the glass cloth can be increased by a heat cleaning treatment that is easy to operate, instead of complicated chemical leaching, and can be performed extremely economically. Therefore, by incorporating the filter cloth of the present invention, it is possible to provide a diesel dust removal device which is expected to appear, and it is extremely effective for measures to reduce particulate matter emitted from diesel vehicles.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01J 35/06 F01N 3/02 301A F01N 3/02 301 321A 321 3/10 A 3/10 B01D 53/36 103C F-term (reference) 3G090 AA01 AA03 BA01 3G091 AA02 AA18 AB02 AB03 AB13 BA01 BA39 CA01 GA05 GA16 GB05W GB06W GB07W HA29 4D019 AA01 BA02 BA04 BA06 BB02 BB10 BC07 CA02 CB04 4D048 AA14 BA01 BA30B03A07 BC03 BC DA06 EA09

Claims (14)

[Claims] 1. A filter cloth of a laminated body for a catalyst element installed in an exhaust gas particulate removing apparatus, comprising a plurality of layers in which two types of glass cloths are combined in pairs, wherein the glass cloth of each layer is A filter cloth characterized by being rich in quartz containing a quartz content of 90% or more, wherein a metal catalyst is supported on the glass cloth. 2. The filter cloth according to claim 1, wherein the glass cloth of each layer is a glass cloth or a silica cloth woven using E glass fiber filaments or S glass fiber filaments. 3. The glass cloth of each layer is obtained by heat-cleaning a glass cloth or a silica cloth woven using E glass fiber filaments or S glass fiber filaments near the glass transition point. 3. The filter cloth according to 1 or 2. 4. The filter cloth according to claim 1, wherein the metal catalyst is a metal oxide catalyst and / or a reduced metal catalyst. 5. The filter cloth according to claim 1, wherein the metal catalyst is a platinum group metal catalyst or an actide-based catalyst. 6. The filter cloth according to claim 1, wherein the glass cloth pair of each layer of the laminate comprises a combination of at least three ripstop fabrics and one plain woven fabric. 7. The glass fiber filament is 3 to 15 μm.
The filter cloth according to claim 2 or 3, wherein the filter cloth has a monofilament diameter of: 8. The filter cloth according to claim 4, wherein the layers supporting the metal oxide catalyst and the reduced metal catalyst are alternately arranged. 9. The filter cloth according to claim 5, wherein a platinum group metal catalyst is supported on the surface of the glass filament carrier via a chromate layer. 10. The catalyst filter cloth according to claim 5, wherein the platinum group metal catalyst is a platinum catalyst or a platinum-palladium-rhodium-based three-way catalyst. 11. A catalyst element for an exhaust gas particulate removing device, comprising the filter cloth according to claim 1. Description: 12. The catalyst element according to claim 11, which is used in an exhaust gas particulate removal device mounted on an automobile driven by an internal combustion engine. 13. The catalyst element according to claim 11, which is used for a diesel dust removal device mounted on a diesel engine automobile. 14. The catalyst element according to claim 12, wherein the catalyst element is a folding pleated structure in which exhaust gas fine particles are circulated in a through flow in the filter cloth catalyst layer of the catalyst element and catalytic combustion is performed at the same time.