JP2006006988A - Metal filter and exhaust gas purifier using the metal filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal filter and an exhaust gas purifier using the metal filter capable of reliably removing a harmful substance and purifying exhaust gas more satisfactorily. <P>SOLUTION: Unburned graphite fine particles captured by a metal porous bodies 13 and catalyst-carrying ceramic granules 15 that constitute the metal filter 1 are heated and combusted by the metal porous bodies 13 of the metal filter 1, the catalyst-carrying ceramic granules 15 and ambient atmosphere which have a high temperature. Therein, the catalyst-carrying ceramic granules 15 which carry a catalyst facilitating the combustion of the graphite fine particles are packed into interlayer apertures 14 of the corrugated roll-shaped metal porous bodies 13 and, thereby, the unburned graphite fine particles are removed from the metal filter 1 by facilitating the combustion by the aid of the catalyst. As a result, a flow F of the exhausted gas passing through the metal filter 1 is exhausted as clean gas containing no graphite fine particle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metal filter and an exhaust gas purification apparatus using the metal filter. For example, the present invention captures black smoke particles contained in combustion exhaust gas of an internal combustion engine such as a diesel engine, and burns and removes the captured black smoke particles. The present invention relates to a metal filter for regenerating a metal filter, and an exhaust gas purification apparatus using the metal filter.

  A large amount of carbon particulates (so-called black smoke) exists in the exhaust gas of diesel vehicles, and these carbon particulates flew into the air for a long time after being discharged into the air through the exhaust passage, and finally , Fall down on the floor, road, clothes, etc. By the way, since carbon adsorbs things well, various chemical substances such as carcinogenic substances are adsorbed by carbon fine particles floating in the air, and humans inhale these carbon fine particles into the human body. In recent years, it has been reported that cancer and respiratory diseases are caused.

For this reason, emission control of particulate matter (PM) from diesel vehicles has become an important issue. Therefore, as a means to protect environmental air from diesel black smoke pollution, a black smoke collection device in which a black smoke removal filter made of metal fibers, honeycomb-shaped elements, etc. is installed in the exhaust passage of a diesel engine mounted on a vehicle has been provided. ing.
However, in this type of black smoke removal filter, if the mesh is made fine, the collection efficiency of black smoke particles is improved, but the trapped black smoke particles are clogged and the pressure loss increases. On the other hand, if the mesh is roughened, there is a problem that the collection efficiency of the black smoke particulates is lowered.

As a means to eliminate such inconvenience, diesel using a metal porous body in which a corrugated metal plate in which a large number of through-holes having burr-like protrusions at the periphery are formed in the crest and trough are spirally wound Metal filters for engines have been proposed (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).
This metal filter is made of a metal porous body in which a metal plate in which a large number of through-holes having burr-shaped protrusions at the periphery are formed in a corrugated or uneven crest and trough is spirally wound. In the spirally wound state, the burr-like projections are positioned and meshed between the opposing surfaces of the metal plate, and a gap serving as an exhaust gas passage is stably formed.
When the exhaust gas passes through this gap, unburned black smoke particles suspended in the exhaust gas are trapped by the surface of the crests and troughs of the metal plate and a large number of burr-like projections, and the high-temperature metal It is heated and burned by the filter and the ambient atmosphere (exhaust gas) and removed from the metal filter.

Further, as shown in FIGS. 18 to 20, as the metal plate, a through hole 101 is provided in a peak portion and a valley portion, and the protrusions 102 are arranged in a row corresponding to a lower portion in the peak portion and an upper portion in the valley portion. A metal filter 106 made of a porous metal body 105 that uses a metal plate provided on the 104 side and winds the metal plate into a multilayer spiral shape to form a corrugated roll has also been proposed.
According to this metal filter 106, by providing the protrusions 102 in the row-shaped recesses 104, the ratio of the cross-sectional area of the black smoke fine particles to the cross-sectional area of the interlaminar channel 107 in the interlaminar gap 107 is reduced. By increasing, the removal efficiency of the black smoke fine particles can be improved.
JP-A-9-245938 (FIGS. 1 to 6) Japanese Patent Laid-Open No. 11-257048 (FIGS. 1 to 4) JP 2002-47915 A (FIGS. 1 to 3)

  The problem to be solved is that the conventional metal filter does not sufficiently remove harmful substances such as nitrogen oxides contained in the exhaust gas together with the black smoke particles.

  The present invention has been made in view of the above-mentioned circumstances, and is capable of reliably removing harmful substances such as nitrogen oxides together with black smoke particles and further purifying exhaust gas, and the metal filter. An object of the present invention is to provide an exhaust gas purifying apparatus using the.

In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that a corrugated metal plate having a plurality of through-holes having a planar protrusion at the edge and repeating a row of undulations is arranged in the wave direction. A metal filter that has a metal porous body wound up or folded in multiple layers toward the surface, passes exhaust gas through an interlayer gap of the metal porous body, and captures and removes harmful particulates contained in the exhaust gas In this regard, the interlayer gap is characterized by being filled or semi-filled with catalyst particles for removing or assisting removal of harmful substances contained in the exhaust gas.
Here, filling does not mean 100% filling of the interlayer gap, and half filling means a filling degree between 5% and 95%, and a space that allows exhaust gas to flow smoothly. Shall be secured.
The catalyst particles include a powdery body. A metal plate is a broad concept including metal foil. In addition, when the metal plate is rolled up or folded in multiple layers, when the sheet is folded or folded in two, it is not only wound or folded in a state where a plurality of sheets are stacked, but also, for example, another type of metal plate or metal band It is a concept that includes a case where a plate or a metal wire is sandwiched between and rolled up. Moreover, the shape of the said through-hole is arbitrary.

  A second aspect of the present invention relates to the metal filter according to the first aspect, wherein the catalyst particles are spherical.

  A third aspect of the present invention relates to the metal filter according to the first or second aspect, wherein the catalyst particles are formed by coating ceramic particles with a catalyst.

  According to a fourth aspect of the invention, there is provided the metal filter according to the first or second aspect, wherein the catalyst particles are formed by coating metal particles with a catalyst.

  The invention according to claim 5 relates to the metal filter according to any one of claims 1 to 4, wherein the catalyst includes a catalyst for promoting combustion of the trapped harmful particulates. It is a feature.

  The invention according to claim 6 relates to the metal filter according to any one of claims 1 to 5, wherein the catalyst reduces at least nitrogen oxides as the harmful substances contained in the exhaust gas. It is characterized by containing the catalyst.

  The invention according to claim 7 relates to the metal filter according to any one of claims 1 to 6, wherein black smoke particulates contained in diesel exhaust gas as the exhaust gas are captured and removed. It is said.

  An exhaust gas purification apparatus according to an eighth aspect of the present invention includes the metal filter according to any one of the first to seventh aspects on an exhaust path, and the exhaust gas is disposed in the interlayer gap of the metal porous body. It is characterized by passing through.

  According to the configuration of the present invention, the interstices of the metal porous body are filled or semi-filled with catalyst particles that remove or assist the removal of harmful substances contained in the exhaust gas, thereby causing harmful effects such as nitrogen oxides. The material can be reliably removed and the exhaust gas can be further purified.

  By filling or semi-filling catalyst particles that remove or assist the removal of harmful substances contained in the exhaust gas in the interlayer gaps of the porous metal body, harmful substances such as nitrogen oxides are reliably removed, The purpose of further purifying exhaust gas has been realized.

  FIG. 1 is a partially enlarged perspective view of a metal filter according to a first embodiment of the present invention, FIG. 2 is a schematic cross-sectional view showing a schematic configuration of a diesel particulate removing device using the metal filter, and FIG. FIG. 4 is a partially enlarged cross-sectional view of the metal filter, and FIG. 5 is a view of one of the metal filters. FIG. 4 is an explanatory view for explaining a mounting structure in which the diesel particulate removing device is attached to an exhaust pipe of a diesel engine of a diesel vehicle. FIG. 6 is an explanatory view for explaining a manufacturing method of the metal filter.

As shown in FIG. 3, the diesel particulate removing device 2 using the metal filter 1 of this example is mounted on a diesel vehicle and used immediately after the diesel engine 8, as shown in FIG. , A plurality of (two in this example) filter units including the metal filter 1 in the container 5 and the introduction part 3 having the diesel exhaust gas inlet 3a, the exhaust part 4 having the diesel exhaust gas outlet 4a, and the container 5 6 and 6 is schematically composed of an apparatus main body 7 in which 6 and 6 are accommodated.
In addition, a collision plate S is provided inside the introduction portion 3 in order to decelerate and uniformly disperse the diesel exhaust gas introduced at a high speed from the inflow port 3 a in the container 5.
As shown in FIG. 3, the diesel particulate removal device 2 is attached immediately after the diesel engine 8 via the exhaust pipe L, and the diesel particulate removal device 2 has a high-temperature diesel exhaust discharged from the diesel engine 8. Gas is introduced.

The filter unit 6 disposed in the container 5 is such that it can flow through the inflow port 3a in the process of being included and discharged in diesel exhaust gas, ignite the captured unburned particles, and burn and remove it. Exposed to high temperature diesel exhaust atmosphere.
In addition, the diesel particulate removal apparatus 2 of this example also has a silencing function, and the diesel exhaust gas from which the unburned particles are burned and removed is left out of the vehicle without going through the silencer (muffler) from the outlet 4a. Discharged.

In the apparatus main body 7, two stages of filter units 6, 6 are accommodated in a container 5, including a front stage and a rear stage.
As shown in FIG. 2, the filter unit 6 includes a platinum-based oxidation catalyst 9 provided on the upstream side and supported by a metal mesh, and a metal filter 1 provided on the downstream side.
As shown in FIGS. 1, 4, and 5, the metal filter 1 of this example is a metal plate in which a large number of through-holes 12 having a planar protrusion 11 are formed at the edge, and undulations of sine waves are repeated. Catalyst-shaped catalyst support as an aggregate of powdery bodies supporting a catalyst for promoting the combustion of black smoke fine particles in the interlayer gap 14 of the corrugated roll-shaped metal porous body 13 wound in a multi-layered spiral shape A large number of ceramic particles 15 are filled to form a schematic structure. For example, diesel exhaust gas as combustion exhaust gas is passed through the interlayer gap 14 and used to capture and remove black smoke particles contained in the diesel exhaust gas. .

The catalyst-supporting ceramic particles 15 are made of, for example, alumina (including at least one of α alumina, β alumina, and γ alumina), beryllia, silicon nitride, boron nitride, silicon carbide, zirconia, cordierite, and the like. It is obtained by supporting a catalyst on a sintered body produced by heating ceramic powder at a predetermined high temperature, and filled in the interlayer gap 14.
The catalyst-carrying ceramic particles 15 are filled in the interlayer gap 14 so that a space necessary for the exhaust gas to flow smoothly through the interlayer gap 14 is secured. Here, the filling rate (the ratio of the total volume of the catalyst-supporting ceramic particles 15 accommodated in the interlayer gap 14 to the volume of the interlayer gap 14) is between 5% and 95%, preferably 20% to 80%. Set between%. The catalyst-carrying ceramic particles 15 are sized so that the cross-sectional area thereof is less than or equal to the cross-sectional area of the interlayer gap 14. The exhaust gas is also passed through the gaps between the cluster-like catalyst-supporting ceramic particles 15.
Further, the catalyst-carrying ceramic particles 15 may be packed uniformly in the interlayer gap 14 or may be packed non-uniformly. Moreover, you may arrange | position so that a part of through-hole 12 may be covered. In this case, the catalyst-carrying ceramic particles 15 are arranged in a state of being caught by the planar protrusions 11.

  As the catalyst for promoting the combustion of the black smoke fine particles, a catalyst mainly composed of one or two or more composites selected from the group of α-alumina, β-alumina and γ-alumina, preferably 68 It is preferable from the viewpoint of the stability and durability of the catalytic action. More specifically, it is mainly composed of one or more composites selected from the group consisting of α-alumina, β-alumina, and γ-alumina, and further includes a group of palladium, rhodium, ruthenium, titanium, nickel, iron, and cobalt. Among these, those containing at least one are excellent in catalytic reactivity and very preferable. Alternatively, one or more composites selected from the group consisting of α-alumina, β-alumina, and γ-alumina, mainly containing ruthenium, and further selected from lithium zirconate, titanium oxide, and potassium carbonate. Those containing the selected one are also preferable because of their excellent catalytic reactivity.

The through-holes 12 are provided in crests and troughs that form a row of undulations, and substantially all or a majority of the planar projections 11 correspond to a row-shaped recess corresponding to a lower portion in the crest portion and an upper portion in the trough portion. 16 side is provided.
In FIG. 4, the metal porous body 13 is wound up in such a manner that the crests of the inner layer and the troughs of the outer layer overlap each other, that is, in a mode in which the phases are shifted from each other by 180 degrees. However, the present invention is not limited to this, and the phases between the layers may be randomly shifted from each other, or the phases between the layers may be aligned.

In this example, the pitch of the metal porous body 13 is a square with 0.6 to 4.0 mm, and the through hole 12 has a side with a side of 0.3 to 0.5 mm. These numerical values are examples, and can be changed according to the load and required accuracy. The planar protrusions 11 may protrude somewhat from the row-shaped recesses 16, but it is preferable that substantially all or a majority of the planar projections 11 remain in the column-shaped recesses 16 as much as possible. According to an experiment, it is most preferable that the relationship between the height of the planar protrusion 11 and the depth of the undulating row-shaped recess 16 is set to 0.7D ≦ H ≦ D.
Note that the shape of the through hole is not limited to a quadrangle, and may be a circle, an ellipse, a slit, a triangle, a trapezoid, a rhombus, or a parallelogram, and may be any other shape such as a fixed shape. Moreover, as a raw material of the metal porous body 13, for example, a stainless steel plate such as SUS304 having a thickness of about 40 μm is preferable.

In the method for forming the porous metal body 13 in this example, a long metal flat plate is subjected to wave-shaped bending to form a wave-shaped metal plate. A press working is performed to pierce the through-holes 12, and at the same time as the through-holes 12 are pierced, the surface projections 11 are formed in the row-shaped recesses 16. That is, when the through-hole 12 is drilled, the metal piece at the position where the through-hole 12 is formed is not completely removed, leaving one side corresponding to the edge of the through-hole 12 and removing the metal piece. The through-holes 12 and the planar protrusions 11 are formed at the same time by being bent and provided on the side of the row-shaped recess 16.
As shown in FIG. 6, the metal filter 1 is wound around the take-up shaft 21 in a state where the metal porous body 13 thus produced is folded back by a horizontal take-up shaft 21, for example, as shown in FIG. However, the catalyst-carrying ceramic particles 15 are supplied to the upper and lower portions of the metal porous body 13 using the chute portions 22a and 22b in accordance with the rotational speed of the winding shaft 21, and each trough row is arranged. The catalyst-carrying ceramic particles 15 are arranged in the recess 16.

Thus, at the same time as winding the metal porous body 13, the catalyst-supporting ceramic particles 15 are arranged in the interlayer gap 14.
Here, the chute portions 22a and 22b fall while sliding the catalyst-carrying ceramic particles 15 on the metal plate along the width direction of the metal porous body 13 so that the catalyst-carrying ceramic particles 15 are simultaneously supplied. And a partition plate standing on the inclined flat plate and guiding the catalyst-supporting ceramic particles 15.
Note that the chute portions 22a and 22b may be displaced (retracted), for example, in order to adjust the supply position of the catalyst-carrying ceramic particles 15 in accordance with the winding of the metal porous body 13.

Since the planar protrusion 11 has a function as a fine collision plate for exhaust gas, it preferably has a certain large area. In this example, as shown in FIG. 1, among the four sides constituting the edge of the through-hole 12, triangular planar protrusions 11 are formed on the two sides on the upstream side and the downstream side of the exhaust gas flow F. A trapezoidal planar protrusion 11 is erected on the other two sides.
However, trapezoidal planar protrusions 11 are erected on the two upstream and downstream sides of the exhaust gas flow F, and triangular planar protrusions 11 are erected on the remaining two sides. You may do it. The shape of the planar protrusion 11 is not limited to the above-described triangle or trapezoid, and can be arbitrarily set as necessary.

The metal filter 1 having the above-described configuration is such that when the diesel exhaust gas passes through the interlayer gap 14 of the metal filter 1 when the diesel engine is operated, the planar protrusion 11 acts as an obstacle to the flow F. Since it acts as a speed reducing piece, a course changing piece, or a through hole introducing piece, unburned black smoke particles floating in the exhaust gas are captured on the front and back surfaces of the metal plate in the vicinity of the planar protrusion 11 and the through hole 12. It becomes easy.
The catalyst-carrying ceramic particles 15 accommodated in the interlayer gap 14 also function as an obstacle to the flow F, and the unburned black smoke particles are also captured on the surface of the catalyst-carrying ceramic particles 15.

The unburned black smoke particles trapped by the metal porous body 13 and the catalyst-supporting ceramic particles 15 constituting the metal filter 1 are the high-temperature metal porous body 13 and catalyst-supporting ceramic particles 15 of the metal filter 1 and the surroundings. It is heated by the atmosphere (exhaust gas) and burns. In this way, the unburned black smoke particles are heated and burned, and are removed from the metal filter 1.
Here, the interstices 14 of the corrugated roll-shaped metal porous body 13 are filled with catalyst-carrying ceramic particles 15 carrying a catalyst for promoting the combustion of black smoke fine particles. Burnt black smoke particles are promoted to burn and are removed from the metal filter 1. As a result, the exhaust gas flow F that has passed through the metal filter 1 is exhausted as a clean gas that does not contain black smoke particulates.

  Thus, according to the configuration of this example, since the catalyst-carrying ceramic particles 15 are filled in the interlayer gap 14, the ratio of the black smoke fine particle obstruction (impact / contact) cross-sectional area to the inter-layer flow path cross-sectional area The unburned black smoke particles are also captured by the catalyst-supporting ceramic particles 15 and combustion is promoted by the catalyst.

In addition, since almost all or a majority of the planar protrusions 11 are provided in the row-shaped recesses 16, the ratio of the cross-sectional area of the black smoke fine particles to the inter-layer channel cross-sectional area (impact / contact) can be remarkably increased.
Therefore, the black smoke removal efficiency can be further increased. Moreover, since it is not necessary to narrow the interlayer gap 14 in order to improve the black smoke removal efficiency, it can be manufactured inexpensively and easily, and clogging does not occur.

FIG. 7 is a schematic sectional view of catalyst-carrying ceramic particles constituting a metal filter according to a second embodiment of the present invention.
The metal filter of this example is greatly different from the metal filter of Example 1 described above in place of the cluster-like catalyst-carrying ceramic particles, as shown in FIG. This is a point using a catalyst-supporting ceramic particle 15A formed with a catalyst layer 25 for promoting combustion.
Since the other configuration is substantially the same as the configuration of the first embodiment described above, the description thereof will be simplified.

In this example, the catalyst of the catalyst layer 25 is the same as the catalyst for promoting the combustion of the black smoke fine particles described in the first embodiment.
In the metal filter having the above-described configuration, when the diesel exhaust gas passes through the interlayer gap 14 of the metal filter during the operation of the diesel engine, the surface protrusion 11 acts as an obstacle to the flow F. As a route change piece or a through hole introduction piece, unburned black smoke particles floating in the exhaust gas are easily captured on the front and back surfaces of the metal filter in the vicinity of the planar protrusion 11 and the through hole 12. .
Further, the catalyst-carrying ceramic particles 15A housed in the interlayer gap 14 also function as an obstacle to the flow F, and the unburned black smoke particles are trapped on the surface of the catalyst-carrying ceramic particles 15A.

The unburned black smoke particles trapped by the metal porous body 13 and the catalyst-supporting ceramic particles 15A constituting the metal filter are the high-temperature metal porous body 13 and catalyst-supporting ceramic particles 15A of the metal filter 1 and the ambient atmosphere. It is heated by (exhaust gas) and burns.
Here, since the ceramic sphere 24 is coated with the catalyst, combustion of the captured black smoke fine particles is promoted.
In this way, the unburned black smoke particles are heated and burned and removed from the metal filter. As a result, the exhaust gas flow F that has passed through the metal filter is exhausted as a clean gas that does not contain black smoke particulates.

  As described above, according to the configuration of this example, substantially the same effect as that of the first embodiment described above can be obtained.

The metal filter of this example differs greatly from the metal filter of Example 1 described above in that the surface of the metal porous body constituting the metal filter is coated with a catalyst for promoting the combustion of trapped black smoke particles. It is a point.
Since the other configuration is substantially the same as the configuration of the first embodiment described above, the description thereof will be simplified.
As the catalyst coated on the surface of the metal porous body, the same catalyst as that for promoting the combustion of the black smoke fine particles described in the first embodiment is used.

  In addition, the metal filter of this example has a corrugated roll shape in which a large number of through-holes 12 having planar protrusions 11 are formed at the edge, and a metal plate that repeats undulation of a sine wave is wound up in a multi-layered spiral shape A large number of catalyst-supporting ceramic particles are accommodated in the interlayer gap 14 of the porous metal body 13, and, for example, diesel exhaust gas as combustion exhaust gas is passed through the interlayer gap 14, and black contained in the diesel exhaust gas Used to capture and remove smoke particulates.

In the metal filter having the above-described configuration, when the diesel exhaust gas passes through the interlayer gap 14 of the metal filter during the operation of the diesel engine, the surface protrusion 11 acts as an obstacle to the flow F. As a route change piece or a through hole introduction piece, unburned black smoke particles floating in the exhaust gas are easily captured on the front and back surfaces of the metal filter in the vicinity of the planar protrusion 11 and the through hole 12. .
Further, the ceramic particles housed in the interlayer gap 14 also function as an obstacle to the flow F, and the unburned black smoke fine particles are trapped on the surface of the ceramic particles.

The unburned black smoke fine particles captured by the metal porous body 13 and ceramic particles constituting the metal filter are heated by the metal porous body 13 and ceramic particles of the high-temperature metal filter and the ambient atmosphere (exhaust gas). And burn.
Here, the catalyst coated on the surface of the metal porous body promotes the combustion of the black smoke particles trapped in the metal porous body, and with the help of this catalyst, the combustion removal of the unburned particles of the black smoke particles Efficiency is increased.
In this way, the unburned black smoke particles are heated and burned, and are removed from the metal filter 1. As a result, the exhaust gas flow F that has passed through the metal filter is exhausted as a clean gas that does not contain black smoke particulates.

  Thus, according to the configuration of this example, the catalyst for accelerating the combustion of the trapped black smoke particles is coated on the surface of the porous metal body constituting the metal filter. Thus, the combustion removal efficiency of unburned fine particles can be further increased.

The metal filter of this example is greatly different from the metal filter of Example 2 described above, instead of the ceramic sphere 24, a catalyst-supported metal sphere formed by coating a metal sphere with a catalyst for burning black smoke fine particles. And a catalyst for promoting combustion of trapped black smoke fine particles is coated on the surface of the metal porous body constituting the metal filter.
Since the configuration other than this is substantially the same as the configuration of the second embodiment described above, the description thereof will be simplified.
As the material of the metal sphere, for example, aluminum, copper, silver or the like is used, and as the catalyst, the same catalyst as that of the catalyst layer 25 for promoting the combustion of the black smoke fine particles described in the second embodiment is used. Use.

According to the configuration of this example, substantially the same effect as that of the second embodiment described above can be obtained.
In addition, the surface of the porous metal body is also coated with a catalyst for promoting the combustion of the trapped black smoke particulates. With the help of this catalyst, the combustion removal efficiency of the unburned particulates is further increased. be able to.

The metal filter of this example differs greatly from the metal filter of Example 1 described above in place of the catalyst-supporting ceramic particles 15, for example, nitrogen oxides contained in the diesel exhaust gas in the ceramic porous body, etc. The catalyst-supporting porous body that supports the catalyst for promoting the decomposition of the metal is housed in the interlayer gap 14 of the corrugated roll-shaped metal porous body 13.
Since the other configuration is substantially the same as the configuration of the first embodiment described above, the description thereof will be simplified.

As the ceramic porous body, a porous body made of zeolite, alumina (including at least one of α alumina, β alumina, and γ alumina), silica, zirconia, cordierite, and the like is used. Examples of the supported catalyst include platinum, palladium, rhodium, iridium, ruthenium and the like.
In this example, the catalyst-supporting porous body is made of, for example, zeolite ion-exchanged with at least one metal selected from platinum, palladium, rhodium, iridium, and ruthenium.
Zeolite has pores of about the size of a molecule (several angstroms), NOx is selectively taken into these pores, and NOx is adsorbed on the active sites of the metal in the pores to cause a reaction. . Further, HC and CO are removed by oxidation.

  According to the configuration of this example, with the aid of a catalyst, black smoke particulates can be captured, unburned particulates can be burned and removed, and at the same time, nitrogen oxides etc. contained in diesel exhaust gas are decomposed. Thus, diesel exhaust gas can be further purified.

FIG. 8 is a schematic cross-sectional view showing a schematic configuration of a diesel particulate removing apparatus according to a sixth embodiment of the present invention.
The diesel particulate removal device of this example is greatly different from the diesel particulate removal device of Example 5 described above, and the former filter unit is configured using an oxidation catalyst and, for example, the metal filter described in Example 1, The latter filter unit is configured by using the metal filter described in the fifth embodiment.
Since the other configuration is substantially the same as the configuration of the fifth embodiment described above, the description thereof will be simplified.

As shown in FIG. 8, the diesel particulate removing apparatus 2A in this example includes an inlet 3 having an inlet 3a, an outlet 4 having an outlet 4a, and filter units 6A and 6B housed in a container 5. And a device main body 7A.
The filter unit 6A includes a platinum-based oxidation catalyst 9 provided on the upstream side and supported by a metal mesh, and a metal filter 1A provided on the downstream side.
The metal filter 1A has a corrugated roll-shaped metal porous body 13 in which a large number of through-holes 12 having planar protrusions 11 are formed at the edge, and a metal plate that repeats undulation of a sine wave is wound up in a multi-layered spiral shape. A large number of catalyst-carrying ceramic particles are filled in the inter-layer gap 14, and the surface of the metal porous body 13 is coated with a catalyst for promoting combustion of trapped black smoke particles. .

  The filter unit 6B has a single metal filter 1B. The metal filter 1B is disposed in the interlayer gap 14 of the corrugated roll-shaped metal porous body 13, the ceramic porous body, and the diesel exhaust gas. A large number of catalyst-carrying porous bodies loaded with a catalyst for decomposing nitrogen oxides and the like contained therein are packed, and the surface of the metal porous body 13 is burned with captured black smoke particles. A catalyst for promotion is coated.

  As described above, according to the configuration of this example, substantially the same effect as that of the fifth embodiment can be obtained.

FIG. 9 is a partially enlarged sectional view of a metal filter according to a seventh embodiment of the present invention, and FIG. 10 is a partially enlarged perspective view of the metal filter.
The difference between the metal filter of this example and the metal filter of Example 1 described above is that the corrugated metal plate and the metal flat plate are wound in a stacked state.
Since the other configuration is substantially the same as the configuration of the first embodiment described above, the description thereof will be simplified.

As shown in FIGS. 9 and 10, the metal filter 1C of this example has a corrugated metal plate 31 that repeatedly undulates a sine wave, and is substantially flat and corrugated compared to the corrugated metal plate 31. A metal flat plate 32 having substantially the same width as the width of the metal plate 31 is wound up in multiple layers while being overlapped with each other, and an interlayer gap formed between the corrugated metal plate 31 and the metal flat plate 32 is formed. A large number of ceramic particles 15 </ b> B are filled in 36.
The corrugated metal plate 31 has a large number of through-holes 34 each having a planar protrusion 33 at the edge, and a large number of metal plates that repeat undulations of a sine wave are wound up in a spiral shape to form a porous metal porous sheet. It is assumed to be a body. On the other hand, the metal flat plate 32 has a large number of through holes 35 that do not have a planar protrusion.

  According to the above configuration, when creating the metal filter, the corrugated metal plate having the planar protrusions and the metal flat plate not having the planar protrusions are overlapped and rolled up. Engagement can be prevented, and therefore winding can be performed precisely and smoothly, and at the same time, the contact area of exhaust gas can be improved.

FIG. 11 is a schematic sectional view of catalyst-carrying ceramic particles constituting a metal filter according to an eighth embodiment of the present invention.
The difference between the metal filter of this example and the metal filter of Example 1 described above is that the catalyst-carrying ceramic particles filling the interlayer gap 14 are provided, and the metal layer as the cladding part is provided on the surface of the ceramic sphere as the core part. In addition, a catalyst layer for promoting combustion of black smoke fine particles is formed on the metal layer.
Since the other configuration is substantially the same as the configuration of the first embodiment described above, the description thereof will be simplified.

The metal filter of this example is a corrugated roll-shaped metal porous body in which a large number of through holes 12 having planar protrusions 11 are formed at the edge, and a metal plate that repeats undulations of a sine wave is wound up in a multi-layered spiral shape. The inter-layer gap 14 of the body 13 is roughly configured by being filled with catalyst-carrying ceramic particles 15C.
As shown in FIG. 11, the catalyst-supporting ceramic particles 15C have a metal layer 37 as a cladding portion formed on the surface of a ceramic sphere 36 as a core portion, and further, black smoke fine particles are formed on the metal layer 37. A catalyst layer 38 for promoting combustion is formed and configured.
The ceramic sphere 36 is made of a material having a specific heat higher than that of the metal plate, for example, and functions as a heat capacity body that maintains a high temperature state.
Here, since the metal layer 37 having a relatively high thermal conductivity is formed on the surface of the ceramic sphere 36, temperature unevenness in the ceramic sphere 36 is eliminated and uniformized. Thereby, the catalyst of the catalyst layer 38 is more activated.

As described above, according to the configuration of this example, substantially the same effect as that of the first embodiment described above can be obtained.
In addition, since the temperature inside the ceramic sphere can be made uniform without being uneven, the catalyst of the catalyst layer 38 can be more activated to increase the combustion efficiency of the fine particles.

FIG. 12 is a partially enlarged sectional view of a metal filter according to the ninth embodiment of the present invention.
The metal filter of this example is greatly different from the metal filter of Example 1 described above, as shown in FIG. 12, which is composed of a corrugated metal porous body 39 that repeats undulation of a substantially rectangular wave or trapezoidal wave, The surface projection 41 or a large number of the surface projections 41 having a main size blocks the flow F of diesel gas in the row-shaped recess 42, and the upstream edge and the downstream of the through hole 43. It is a point provided on the side edge. Further, the catalyst-supporting ceramic particles 15 </ b> D are disposed in the interlayer gap 45.

Thus, according to the configuration of this example, substantially the same effect as described in the first embodiment can be obtained.
In addition, compared to the configuration of Example 1, the ratio of the cross-sectional area of the black smoke fine particles to the cross-sectional area of the interlayer flow path can be improved, and the unburned black smoke fine particles floating in the exhaust gas are made of metal. Since the time for keeping in the interlayer gap of the filter can be increased, the efficiency of capturing the black smoke particles can be further increased.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. Are also included in the present invention.
For example, the case where a rolled-up metal filter is used has been described. If the metal filter is stored in the cylindrical container as densely as possible within a range where pressure deficiency does not become a problem as a back pressure applied to the engine. Since it is good, it is not limited to a wound shape, and may be used in a folded shape, for example.
Moreover, although the case where two stages of filter units are provided in series has been described, the diesel particulate removing device may be configured from a single filter unit, or three or more stages of filter units may be provided in series. However, the filter units may be arranged in parallel and switched for use.

Further, in Example 1, the case where the cluster-like catalyst-carrying ceramic particles 15 are filled in the interlayer gap 14 has been described, but as shown in FIGS. 13 to 15, the area of the cross section including the center is as follows. Spherical catalyst-carrying ceramic particles 15G having the same size as the cross-sectional area of the interlayer gap 62 of the metal porous body 61 constituting the metal filter 1H are arranged between the adjacent through holes 63 in the interlayer gap 62. And may be filled. Since the catalyst-supporting ceramic particles 15G have the same size as the cross-sectional area of the interlayer gap 62, a function as a spacer for maintaining the shape of the metal filter can be provided.
Further, the size of the ceramic particles is not constant, and as shown in FIG. 16, the catalyst-carrying ceramic particles 15H of various sizes are filled in the interlayer gap 66 of the metal porous body 65, and the metal particles The filter 1J may be provided.
Further, as shown in FIG. 17, the overall shape of the cluster-like catalyst-carrying ceramic particles 15J is substantially spherical and filled in the interlayer gap 69 of the metal porous body 68 to constitute the metal filter 1K. May be.

Further, in Example 1, the catalyst-supporting ceramic particles 15 are supplied to the upper and lower portions of the metal porous body 13 while winding the metal porous body 13 in a folded state. The case where the catalyst-carrying ceramic particles 15 are arranged in the row-shaped recesses 16 has been described. However, an adhesive is applied or dispersed in advance in the valleys between the through holes 12 of the metal porous body 13, and then the catalyst is formed. The supported ceramic particles may be held. Alternatively, the catalyst-carrying ceramic particles may be simply sprayed on the metal plate and then wound.
Thus, the catalyst-carrying ceramic particles may be simply held in the interlayer gap without being adhered to the metal plate surface, or the catalyst-carrying ceramic particles may be adhered to the metal plate surface. . By adhering the catalyst-carrying ceramic particles to the surface of the metal plate, the density of the catalyst-carrying ceramic particles in the interlayer gap can always be kept substantially constant.

  The shape of the catalyst-carrying ceramic particles is not limited to a cluster shape or a sphere, and a cylindrical catalyst-carrying ceramic particle may be filled in an interlayer gap, or a disk-shaped catalyst-carrying ceramic particle. You may fill your body. Further, the interlamellar gap may be filled with conical catalyst-carrying ceramic particles or tetrapot-shaped catalyst-carrying ceramic particles. In addition, the shape of the catalyst-carrying ceramic particles may be a polyhedron. Also, it may be indefinite.

In the first embodiment, the oxidation catalyst 9 may be omitted from the filter unit 6 or may be added as necessary.
Further, for example, in the second embodiment, the case where the catalyst layer 25 for promoting the combustion of the black smoke fine particles is formed on the ceramic sphere 24 has been described, but instead of the catalyst-carrying ceramic particles 15A, the black smoke The catalyst itself for promoting combustion of fine particles (for example, alumina (including at least one of α alumina, β alumina, and γ alumina)) or at least nitrogen oxides as harmful substances contained in exhaust gas is reduced. The catalyst itself may be used.

In Example 4, the surface of the metal porous body does not necessarily have to be coated with a catalyst for burning unburned fine particles.
Further, in Example 5, not only the ion exchange method but also platinum or palladium may be supported on the ceramic porous body by, for example, an impregnation method.

In Example 8, instead of the composite sphere formed by forming a metal layer on the surface of the ceramic sphere, a metal sphere may be simply used.
Also, in Example 9, similarly to Example 7, a metal filter may be produced by winding a corrugated metal plate and a metal flat plate in an overlapped state.
In the first to ninth embodiments described above, a metal plate may be used in which substantially all or a majority of the planar protrusions are provided on the side opposite to the row-shaped recesses in the row-like undulations.

  In addition to purifying high-temperature diesel exhaust gas emitted from diesel engines as internal combustion engines such as automobiles, it is also applied to remove nitrogen oxides etc. in exhaust gas emitted from nitric acid manufacturing plants, etc. Can do.

It is a partially expanded perspective view of the metal filter which is 1st Example of this invention. It is a schematic cross section which shows schematic structure of the diesel particulate removal apparatus using the metal filter. It is explanatory drawing for demonstrating the attachment structure in which the diesel particulate removal apparatus was attached to the exhaust pipe of the diesel engine of a diesel vehicle. It is a partially expanded sectional view of the metal filter. It is a partially expanded perspective view of the same metal filter. It is explanatory drawing for demonstrating the manufacturing method of the metal filter. It is a schematic cross section of the catalyst support ceramic particle | grains which comprise the metal filter which is 2nd Example of this invention. It is a schematic cross section which shows schematic structure of the diesel particulate removal apparatus which is 6th Example of this invention. It is a partially expanded sectional view of the metal filter which is 7th Example of this invention. It is a partially expanded perspective view of the same metal filter. It is a schematic cross section of the catalyst carrying ceramic particles constituting the metal filter according to the eighth embodiment of the present invention. It is a partially expanded sectional view of the metal filter which is 9th Example of this invention. It is a partially expanded perspective view of the metal filter which is a modification of 1st Example of this invention. It is a partially expanded cross section of the same metal filter. It is a partially expanded perspective view of the same metal filter. It is a partially expanded perspective view of the metal filter which is another modification of 1st Example of this invention. It is a partially expanded perspective view of the metal filter which is another modification of 1st Example of this invention. It is a figure for demonstrating a prior art. It is a figure for demonstrating a prior art. It is a figure for demonstrating a prior art.

Explanation of symbols

1,1A, 1B, 1C, 1D, 1E, 1H, 1J, 1K Metal filter 2,2A Diesel particulate removal device (exhaust gas purification device)
6, 6A, 6B Filter unit 7, 7A Device main body 8 Diesel engine 11, 33, 41 Planar protrusion 12, 34, 43 Through hole 13, 39, 61, 65, 68 Porous metal 14, 36, 45, 62, 66, 69 Interlayer gap 15, 15A, 15B, 15C, 15D, 15G, 15H, 15J Catalyst-carrying ceramic particles (catalyst particles)
16, 42 Column-shaped recess 31 Metal plate 32 Metal flat plate 35 Through hole

Claims (8)

A large number of through-holes having planar protrusions on the edge are formed, and a corrugated metal plate that repeats undulations in a row is rolled up or folded in multiple layers in the wave direction. A metal filter for passing an exhaust gas through an interlayer gap of the porous metal body to capture and remove harmful fine particles contained in the exhaust gas,
The metal filter, wherein the interlayer gap is filled or semi-filled with catalyst particles for removing or assisting removal of harmful substances contained in the exhaust gas.   The metal filter according to claim 1, wherein the catalyst particles are spherical.   The metal filter according to claim 1, wherein the catalyst particles are made of ceramic particles coated with a catalyst.   3. The metal filter according to claim 1, wherein the catalyst particles are formed by coating metal particles with a catalyst.   5. The metal filter according to claim 1, wherein the catalyst includes a catalyst for promoting combustion of the trapped harmful fine particles.   The metal filter according to any one of claims 1 to 5, wherein the catalyst includes a catalyst for reducing at least nitrogen oxide as the harmful substance contained in the exhaust gas.   The metal filter according to any one of claims 1 to 6, wherein black smoke particulates contained in diesel exhaust gas as the exhaust gas are captured and removed. An exhaust gas purification apparatus comprising the metal filter according to any one of claims 1 to 7 on an exhaust path, wherein the exhaust gas is passed through the interlayer gap of the porous metal body.

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