KR20090031850A - Substrate having corrugated sheet(s) and channel(s) for treating exhaust gases of combustion engines - Google Patents

Abstract

The present invention relates a substrate having corrugated sheet(s) and channel(s) for treating exhaust gases of combustion engines. The present invention also relates to methods for manufacturing and using said substrate having said open channel(s). The substrate (1) comprises at least one corrugated sheet (3) having depressions (3d) and one flat wire mesh sheet (2) having depressions (2d) which is connected to said corrugated sheet (3) and between said flat wire mesh sheet (2) and said corrugated sheet (3) there are at least partially open channels (POC) for exhaust gas (EG) flow, and the depth of depression (2d) of said flat wire mesh sheet (2) is 0.05-0.5 mm smaller than the height of the corrugation (3c) of said corrugated sheet (3).

Description

SUBSTRATE HAVING CORRUGATED SHEET (S) AND CHANNEL (S) FOR TREATING EXHAUST GASES OF COMBUSTION ENGINES}

The present invention relates to a substrate having corrugated sheet (s) and channel (s) for treating exhaust gases of a combustion engine. The invention also relates to a method of making the substrate with the open channel (s).

In order to treat the exhaust gases of combustion engines, substrates with open or closed channels or a combination thereof are used. In the case of open channels, the exhaust flows directly through the substrate. In substrates with closed channels, gas is pressurized to flow through a wall, such as, for example, a ceramic or metallic porous wall. In open channels, gas impurities are greatly reduced, but particle impurities are small, for example by 10 to 15%. The reduction of gas impurities flowing through the filter in the closed channels / walls is high, and also the particle impurities are high, eg 70 to 99%. The problem with closed channels is that the walls are blocked. If the filter is not cleaned in the closed channels / walls, it will gradually become clogged. Pressure loss also increases. One way to keep these channels open is to wash them continuously or periodically.

Substrates have been invented that efficiently reduce particles and gaseous impurities in the exhaust gas in open channels. Accordingly, a method of manufacturing the substrate has also been invented.

For this purpose, the invention features the facts disclosed in the independent claims. Some preferred embodiments of the invention are disclosed in the other claims.

In no way is it limited to the constitutive embodiments of the invention. According to one embodiment of the invention, the catalyst of the invention may be present in a plurality of structures assembled in parallel or in series with respect to the cascade or flow direction of the POC / DPF-structures / substrates.

According to one embodiment of the invention, the substrate comprises corrugated sheet (s) having depressions connected with the flat mesh sheet (s), wherein the flat wire mesh sheet and the corrugation Between the sheet-like sheets there is at least partly channel (s) for the exhaust gas to flow, the depth of the depression being 0.05-0.5 mm smaller than the height of the corrugation.

Surprisingly, it was found that the flow of particles in the open channels was substantially improved. The reduction of gaseous impurities in at least partially open channels is also improved.

The depth of the depression is preferably 0.5 to 1.5 mm, and the height of the wrinkles is 1.0 to 3.0 mm. Combining them is very effective both in reducing particles and reducing gas impurities. The depressions may each be, for example, 10-40 mm, 20-30 mm.

The exhaust gas can flow freely through partially open channels, but due to the irregular surface of the wire mesh sheet (s) and the depressions of the sheet, the gas flow rate is reduced over the substrate of the sheet. The irregular surfaces and depressions mix the gas to reduce the standard deviation of gas retention time. The surface of the wire mesh sheet (s) also functions as an effective open particle trap for exhaust gas particles. This combination adds contact of gas and particulate impurities to increase residence time and increase reduction of impurities and particles. Impurity particles adhere more to the mesh sheet than to the smooth sheet. Particularly heavy and large particles adhere onto the surface of the wire mesh sheet (s).

The reduction of particles is highly dependent on the particle source and the composition of the particles. The particles can include varying amounts of volatile organic compounds (VOFs), solid carbon, sulfur, moisture and metal oxides. Standard oxidation catalysts oxidize most of the VOF and in this way can reduce 10 to 60% of the particle weight. With this new invention, particle reduction can be improved up to 80%. With the new invention, it is possible to improve the reduction of gas impurities by more than 90% (> 90%).

An important feature of the new partially open channel is that the blockage is minimal compared to a closed channel or filter where there is no clogging or gradually clogs up if not cleaned. This is very important, and substrates with at least partially open channels according to the invention can be used for most of the required conditions and are also useful in many applications.

Particles attached to at least partially open channel (s) decompose into gaseous impurities which subsequently decompose into harmless compounds. A portion of the gas can flow through the opening of the mesh sheet (s) and the particles adhere to the surface of the sheet (s). This also improves particle reduction. On the other hand, partially open channels are not blocked or minimized, and gas flow rates and pressure losses in the vicinity of the sheet (s) are not reduced. This reduces operational failures and doubles the efficiency of the partially open channel.

The shape of the opening of the mesh sheet (s) can vary. The opening can be in the form of a channel, a square, a diamond or a hole. For example, in diamond-shaped mesh sheets, the wires may be one level and crosswise to one another.

The pressure difference between the sides of the mesh sheet (s) increases the flow of exhaust gas through the pores of the mesh sheet. This phenomenon allows the particles to adhere on the support, improving the reduction of particles from the exhaust gas.

According to one embodiment of the invention, the corrugated sheet is a corrugated wire mesh sheet. This increases the contact of the impurity gas with the particles, thereby increasing the residence time and reducing the impurities. This effectively reduces the valuables of the impurity particles of the exhaust gas. The collision of gases also allows the gas to better contact the catalytically active material, increasing the residence time of the particles in the substrate and improving the reduction of gas impurities.

Preferably, there are open channels on both sides of the mesh sheet. The structure of the wire mesh sheet is simple and easy to manufacture, for example, the reduction of particles is relatively high compared to the smooth sheet used in open channels, for example.

According to one embodiment of the invention, the flat wire mesh sheet has a depression. This also increases the reduction of impurity gas particles by reducing the flow rate of impurity gas and increasing the adhesion of particles on the support.

According to one embodiment of the invention, the depression of the corrugated sheet is mated with the depression of the flat wire mesh sheet. This improves the strength of the substrate because the layers are fixed relative to each other.

According to one embodiment of the invention, the median opening size of the mesh sheet is 0.01 to 0.5 mm, preferably 0.05 to 0.3 mm, more preferably 0.08 to 0.2 mm.

According to one embodiment of the invention, the mesh diameter is 0.08-0.24 mm. The mesh diameter is preferably 0.1 to 0.15 mm. Thus, the mechanical strength is high and the pressure loss of the flowing gas is small.

According to one embodiment of the present invention, the mesh number of the mesh sheet is 30 to 300. At least a portion of the exhaust gas may flow through the opening of the mesh sheet. This allows particles of the exhaust gas to adhere to the surface of the support, substantially improving the reduction of the particles.

According to one embodiment of the invention, the flat wire mesh sheet and the corrugated sheet may be attached to each other by welding / brazing. This further improves the strength of the substrate.

According to one embodiment of the invention, the substrate (s) are at least partially covered by a support and / or a catalytic material. The median pore size of the support is preferably greater than 5 nm, preferably 10 to 50 nm, more preferably 15 to 20 nm. The optimal pore size of the support depends on the environment of the gas flowing near the mesh sheet (s) and the exhaust gas. The exhaust gas may for example have a median particle size of 5 to 200 nm and the median pore size may for example 5 to 20 nm.

Preferably the support comprises coarse particles and / or fibers protruding from the plane of the support. Preferably the median particle size of the support is greater than 0.4 μm, for example 1.5 to 3.5 μm. This substantially increases the adhesion of the particles to improve the reduction of the particles in the substrate.

According to one embodiment of the present invention, the substrate (s) is substantially covered by supports having particles having an intermediate particle size greater than 1.4 μm and / or pores greater than 10 nm. This increases the adhesion of the particles to the sheet to improve the reduction of impurity particles.

Particles of exhaust gas of the combustion engine can be efficiently processed by a substrate having mesh sheet (s) with channels partially open according to the invention. Surprisingly, the reduction of impurity particles is high relative to conventional substrates. In addition, the reduction of gas impurities is also high. The mesh sheet (s) according to the invention are not blocked or the blockage is minimized so as not to affect the flow rate of the exhaust gas in the substrate. In addition, pressure loss at the substrate is minimized.

The substrate can be, for example, a particle oxidation catalyst (POC) or an SCR catalyst. The substrate may also be a hydrolysis catalyst. The substrate can preferably be used to purify the impurity particles of the exhaust gas of the combustion engine. The structure of the substrate can vary. The structure of the substrate can be, for example, wound, stacked or folded.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 shows a substrate having a corrugated sheet with depressions and a flat wire mesh sheet.

In FIG. 1, the board | substrate 1 contains the corrugated smooth sheet 3 which has the recessed part 3d, and the flat wire mesh sheet 2 which has the recessed part 2d. These sheets are joined to each other and there is a partially open channel POC between which the exhaust gases EG can flow. The depression 3d of the corrugated sheet 3 is matched to the depression 2d of the flat wire mesh sheet 2. The depth of the recessed portion 2d of the flat wire mesh sheet 2 is smaller than the height of the corrugated portion 3c of the corrugated sheet 3. In the present embodiment, the depths of the depressions 2d and 3d are about 1 mm, and the height of the pleats 3c is about 2 mm.

Claims (14)

In a substrate for treating exhaust gas of a combustion engine, having a corrugated sheet (s) and channel (s), the substrate 1 comprises at least one corrugated sheet 3 having a depression 3d, A flat wire mesh sheet (2) having a depression (2d) and connected to the corrugated sheet, and having an exhaust between the flat wire mesh sheet (2) and the corrugated sheet (3). There is a channel POC at which at least a portion of the gas EG can flow, and the depth of the depression 2d of the flat wire mesh sheet 2 is a corrugated portion of the corrugated sheet 3. A substrate for processing exhaust gas of a combustion engine, characterized in that 0.05 to 0.5 mm smaller than the height of 3c). The substrate for treating exhaust gas of a combustion engine according to claim 1, wherein the corrugated sheet (3) is a corrugated wire mesh sheet. The combustion engine exhaust according to claim 1 or 2, wherein the depression 3d of the corrugated sheet 3 is matched to the depression 2d of the flat wire mesh sheet 2. Substrate for gas treatment. Substrate according to any one of the preceding claims, characterized in that the depth of the depressions (2d, 3d) is 0.5 to 1.5 mm. The substrate for treating exhaust gas of a combustion engine according to any one of the preceding claims, characterized in that the height of the pleats (3c) is 1.0 to 3.0 mm. The substrate for treating exhaust gas of a combustion engine according to any one of the preceding claims, wherein the mesh number of the mesh sheet is 30 to 300. The exhaust gas treatment of a combustion engine according to any one of the preceding claims, characterized in that the flattened wire mesh sheet (2) and the corrugated sheet (3) are joined to each other by welding or brazing. Board. Substrate according to one of the preceding claims, characterized in that the sheets (2, 3) are at least partly covered by a support and / or catalyst material. A method of using the substrate according to claim 1 for purifying exhaust gas (EG). In the substrate manufacturing method provided with the corrugated sheet (s) for processing the exhaust gas of a combustion engine, the flat wire mesh sheet 2 which has the recessed part 2d, and the valley which has the recessed part 3d is provided. There is a channel POC connected to the plate sheet 3 and at least a portion of which the exhaust gas EG can flow between the flat wire mesh sheet 2 and the corrugated sheet 3 is opened. The substrate manufacturing method provided with the corrugated sheet (s) characterized by the depth of (3d) being smaller than the height of the wrinkle part (3c). 10. A method according to claim 9, characterized in that the flattened wire mesh sheet (2) is connected to the corrugated sheet (3) by rolling. The substrate with corrugated sheet (s) according to claim 9, characterized in that the flattened wire mesh sheet (2) is connected to the corrugated sheet (3) by stacking or folding. Manufacturing method. The flat wire mesh sheet 2 according to any one of claims 9 to 11 has recesses 2d and 3d in the flat wire mesh sheet 2 and the corrugated sheet 3. And a corrugated sheet (s), characterized in that it is connected to the corrugated sheet (3) by forming these recesses (2d, 3d) to mate with each other. The corrugated sheet (s) according to any one of claims 9 to 12, wherein the flattened wire mesh sheet (2) and the corrugated sheet (3) are joined to each other by welding or brazing. Substrate manufacturing method comprising a.

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