JPH09268909A - Seal material and particulate trap device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify assembly by installing inorganic mats on both surface of a skeleton which consists of a metal plate so as to form the inorganic mat of one side as an inorganic mat including a component which is irreversibly expanded at the time of heating, in a seal material arranged holding a ceramic filter in a metal case. SOLUTION: A ceramic filter 6 is held in a metal case 12 by a pair of seal material 2, and gas including dust supplied from a leading inlet 10 is cleaned. The ceramic filter 6 is regenerated by a backwashing means 7 for generating backwashing gas flow intermittently. In this case, the seal material 2 is constituted by installing an inorganic mat on both surfaces of a skeleton which consists of a metal plate, and handling of the seal material 2 at the time of assembly is carried out easily. One side of the inorganic mat is formed as an inorganic mat including a component which is expanded irreversibly at the time of heating, heating is carried out after the ceramic filter 6 is assembled, and thereby, a force for holding the ceramic filter 6 on a prescribed position is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particulate trap device for removing particulates contained in exhaust gas of a diesel engine or the like.

[0002]

2. Description of the Related Art In the exhaust gas of a diesel engine,
Particulates containing carbon as a main component are contained at a considerable concentration (150 to 250 mg / Nm ³ ), which causes pollution. Therefore, various particulate trap devices including a ceramic filter for capturing and removing fine particles from exhaust gas of a diesel engine have been proposed. The sealing material has a function of sealing so that dust does not leak from the dust-containing gas side space to the clean gas side space, but in many cases, the sealing material has a function of holding a ceramic filter in a container together with a sealing function, These functions need to be maintained not only at low temperatures but also at high temperatures.

[0003] Regeneration methods of the ceramic filter of the particulate trap device include an incineration regeneration method in which the particulates captured by the ceramic filter are incinerated in the ceramic filter, and a backwash gas flowing from the outlet of the filtered clean gas. In addition, there is known a backwashing regeneration method in which the particulates are separated from the ceramics filter, and the particulates are flowed out of the ceramics filter with a backwashing gas. In the former method, the structure of the apparatus is relatively simple. However, the ceramic filter is exposed to high-temperature incineration heat of the particulates and is thermally damaged, and the non-combustible component (ash) contained in the particulates causes the ceramic filter to fail. Clogging issues need to be considered.

In the latter method, since the ceramics filter is not affected by the heat of particulate burning, the heating temperature of the ceramics filter is the temperature of the exhaust gas (500 ° C.).
Degree), which is advantageous in that the problem of thermal damage can be avoided. Further, the ceramic filter is not clogged by the ash. However, in order to perform backwashing regeneration, the back pressure of the backwash gas is applied to the ceramics filter, and mechanical stress is repeatedly applied to the sealing material of the ceramics filter. There is a problem that the material is likely to deteriorate.

[0005] It is necessary that the sealing material does not undergo material deterioration such as sagging at high temperatures and that the sealing material is not damaged by a strong backwash gas flow. As a sealing material for the particulate trap device for this purpose, for example, the sealing materials shown in FIGS. 4 and 5 have been proposed in Japanese Patent Application Laid-Open No. 1-306452.

In FIG. 4, 2 is a sealing material, 6 is a ceramics filter, 8 is a dust-containing gas side space, 12 is a metal case, 15 is a clean gas side space, and 101 is a stopper. Here, the dust-containing gas side space 8 and the clean gas side space 15
Since the sealing material 2 is disposed between the stoppers 101 provided on both sides, the dust-containing gas space side 8 and the clean gas space side 1
5 (a large pressure difference is generated between the clean gas space side and the dust-containing gas space side during back washing).
It will not slip or be blown away.

FIG. 5 shows a ceramic filter 6.
A groove 102 is provided in the groove 102. Most of the sealing material 2 is in the groove 102, and the sealing material is not displaced or blown off by the differential pressure as in the case of FIG. Further, the seal material 2 shown in FIGS. 4 and 5 is a material obtained by wrapping an inorganic mat containing a component which irreversibly expands when heated with a cloth made of quartz glass fiber. Also, the sealing material does not scatter.

However, in this sealing material, since the sealing material is flexible, it takes time to mount the ceramic filter, and there is a difference in the thermal expansion coefficient between the ceramic filter having a small thermal expansion coefficient and the metal casing having a large thermal expansion coefficient holding the ceramic filter. Because of this, the holding force of the seal material is loosened at high temperatures, and the seal material deteriorates due to the differential pressure of backwash, vibration transmitted from diesel engine etc. and strong backwash gas flow,
When used for a long time, the sealing material was eventually damaged, and a problem of leakage of particulates occurred.

Japanese Utility Model Laid-Open Publication No. 1-124321 discloses a seal material having substantially the same configuration as above, which holds a ceramic catalyst carrier or ceramic filter having a honeycomb shape. However, there is a similar problem regarding the durability of the sealing material when used for a long time. Furthermore, in the particulate trap apparatus by the regenerating method in which the particulates are incinerated in the ceramics filter, there is a problem that the sealing material is exposed to high temperature, so that the sealing material is exposed to heat and the sealing function and the holding function are lost.

In the particulate trap apparatus, the particulates are prevented from leaking into the clean gas side space from a sealing material provided between a ceramic filter such as cordierite having a low thermal expansion coefficient and a metal casing having a high thermal expansion coefficient. However, there is still a problem with long-term durability.

[0011]

DISCLOSURE OF THE INVENTION The present invention is easy to assemble, has a sealing function and a holding power for a ceramic filter in a range between a normal temperature and an exhaust gas temperature, and receives vibration and a differential pressure of a backwash gas. An object of the present invention is to provide a sealing material that can be used for a long time even under conditions and a particulate trap device provided with the sealing material.

[0012]

In a particulate trap device of the present invention, a ceramics filter having a dust-containing gas passage and a clean gas passage defined by a filtration wall is provided with a dust-containing gas side space in a metal case. A backwash gas flow, which is retained in the metal case by a pair of sealing materials provided at the boundary with the clean gas side space and flows from the clean gas channel side to the dust-containing gas channel side through the filter wall, is generated intermittently. A particulate trap device in which a ceramics filter is regenerated by a backwashing means provided at an outflow portion of a clean gas to be used, in which the sealing material is an inorganic material on both sides of a skeleton made of a hollow frame-shaped metal plate having a flat surface. Is attached, the inorganic mat on one side contains a component that expands irreversibly when heated, and the inorganic mat on one side of the metal plate is The edge of the opposite end faces of the pass filter is pressed against each of the inorganic mat in the other side of the metal plate is pressed against the inner surface of the metal case.

In the sealing material used in the particulate trap device of the present invention, since the inorganic mats are attached to both sides of the skeleton made of a flat metal plate, rigidity is imparted by the skeleton and incorporated in the particulate trap device. It is easy to handle the sealing material. Thereby, the sealing material can be inserted into the metal case with one touch, and the ceramics filter can be incorporated into the metal case by a simple operation.

Also, since at least one of the inorganic mats is an inorganic mat containing a component that irreversibly expands when heated, the ceramic filter is assembled in a metal case and then heated to ensure the sealing property and at the same time, the ceramic filter can be used. A holding force for holding at a predetermined position can be provided. In addition, when the sealing material is heated, heat is transmitted to the layer containing the irreversibly expanding component through the metal plate having good heat conductivity, so that the layer containing the irreversibly expanding component is expanded by the heat to form a ceramic filter. The heat treatment of the sealing material for imparting the holding force can be easily performed. In this heat treatment, the metal case is put into a hot blast stove and heated to 550 to 600 ° C.
Heating is performed by sending hot air of about 0 ° C. from the inlet of the apparatus, and heating may be performed. Alternatively, heating may be performed using exhaust gas of a diesel engine.

[0015] In the particulate trap device of the present invention, the inorganic mats attached to both surfaces may each contain a component that irreversibly expands when heated. In this case, the inorganic mat on one surface is irreversibly heated when heated. It is also possible to use a laminated mat of a layer containing a component which expands to a thickness and an inorganic fiber layer. In this case, even if the space between the ceramic filter and the metal case slightly increases due to the difference in thermal expansion between the ceramic filter having a small coefficient of thermal expansion and the metal case having a large coefficient of thermal expansion, the holding force of the ceramic filter is not loosened.

In the particulate trap device of the present invention, a part of the skeleton of the metal plate may be a guard portion for covering the surface of the inorganic mat in the clean gas side space of the ceramics filter, thereby generating at the time of back washing. The surface of the inorganic mat of the sealing material exposed in the clean gas side space is protected from the strong backwash gas flow. Accordingly, deterioration of the sealing material can be prevented, and a durable and highly reliable particulate trap device can be provided.

In the particulate trap device of the present invention, the component contained in the inorganic mat that expands irreversibly upon heating is preferably vermiculite. Vermiculite is a mineral containing structural water, also called vermiculite. When heated, structural water is released at around 400 ° C., and the cleavage surface of the layered crystal is separated and swells to 10 to 30 times its original volume. This expansion occurs irreversibly, resulting in an expanded body having considerable elasticity. The sealing material utilizes the expansion of the vermiculite due to heating and the holding force due to the elasticity of the expanded body. The amount of vermiculite blended in the inorganic mat is preferably at least 5% by weight so that there is irreversible expansion upon heating and a sealing function and a holding function can be imparted. On the other hand, if the amount is too large, the amount of expansion is excessive and it is difficult to use.

A mat containing a component that expands irreversibly when heated is commercially available, for example, from Japan Pillar Industry Co., Ltd. under the trade name of Pillar Mat. Although this mat is a composite material of inorganic fibers and vermiculite, it does not have much elasticity and its heat resistance is rather low, so that it cannot be used for a long time at a high temperature of 600 ° C. or higher. There is also a sealing material in which an inorganic mat such as a pillar mat is wrapped with a cloth of quartz glass fiber, but the durability is improved to some extent, but it is not always sufficient.
Quartz glass cloth is relatively expensive.

In the particulate trap apparatus of the present invention, the ceramic filter is backwashed and regenerated, so that the operating temperature of the ceramic filter is the same as that of the exhaust gas.
It is about 0 ° C. Therefore, even when an inorganic mat containing vermiculite is used, the heat resistance is satisfied. But,
The reliability of the particulate trap device is further improved by using a laminated mat in which an inorganic fiber layer having higher heat resistance is stacked on the side that comes into contact with the ceramic filter whose temperature is higher than that of the metal case side.

It is preferable that an organic and / or inorganic binder is added to the inorganic fiber layer in order to maintain its shape. If the amount of the organic and inorganic binders added to the inorganic mat is too large, the elasticity becomes poor. Therefore, the total amount of the organic and inorganic binders is preferably 30% by weight or less.

The skeleton metal plate is preferably made of stainless steel which has heat resistance and is resistant to corrosion.
Excellent durability can be ensured by using a stainless steel plate such as SUS316L. The inorganic fiber layer has heat resistance and high elasticity, so that the fiber layer mainly contains silica such as quartz glass, or the ceramic fiber contains alumina and silica as main components and contains 60% by weight or more of alumina. Preferably, it is a layer.

In the particulate trap device of the present invention, the ceramics filter may have a rectangular parallelepiped shape, and may have a flow path in a direction in which the dust-containing gas flow path and the clean gas flow path intersect. When the ceramics filter has a rectangular parallelepiped shape, a plurality of ceramics filters can be arranged side by side and incorporated in one metal case, and the effective filtration area of the ceramics filter can be freely increased or decreased.

When a cross-flow type ceramic filter having a flow path in the direction where the dust-containing gas flow path and the clean gas flow path intersect is used, the particulates captured by the ceramic filter are released and discharged from the ceramic filter. However, an opening on the opposite side of the inlet of the dust-containing gas into the dust-containing gas flow path can be used, and by providing a particulate collecting portion on this side, the particulates can be discharged from the ceramics filter. Easy.

The sealing material of the present invention is such that an inorganic mat is attached to both surfaces of a skeleton made of a metal plate in the shape of a hollow frame on a plane, and at least one surface of the inorganic mat contains a component that irreversibly expands when heated. It is characterized by

Since this sealing material has a skeleton made of a heat-resistant metal plate on a flat surface, it is not as flexible as the conventional sealing material and is easy to handle. It can be easily inserted into a metal case such as a ceramics filter. In addition, since the thermal conductivity of the skeleton made of a metal plate is significantly higher than that of the inorganic mat, it is easy to transfer heat to the inorganic mat containing components that expand irreversibly when heated, and the inorganic mat expands with heat. Thus, there is an effect that the treatment for imparting the sealing property and the holding force is easy.

In the sealing material of the present invention, the inorganic mat attached to both sides contains a component which irreversibly expands when heated, and the inorganic mat on one side contains a layer containing a component which irreversibly expands when heated. It may be a laminated mat with layers. The component that irreversibly expands when heated is preferably vermiculite, and the inorganic mat preferably contains 5 to 40% by weight of vermiculite so as to obtain an easy-to-use expansion amount.

Further, in the sealing material of the present invention, a part of the skeleton formed of the metal plate may be used as a guard portion for covering the surface of the inorganic mat attached to one surface of the metal plate. The easy-to-use inorganic mat is protected by the guard. Further, the skeleton metal plate is preferably made of stainless steel having excellent heat resistance and corrosion resistance.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to embodiments, but the present invention is not limited to these embodiments.

FIG. 1 is a longitudinal sectional view showing an example of the particulate trap device of the present invention. In FIG. 1, 1 is a particulate trap device, 2 is a sealing material, 6 is a ceramics filter, 7 is a backwash means, 8 is a dust-containing gas side space, and 9 is a particulate having a sheath heater for igniting the particulate. Receiving part, 10 is a dust-containing gas (diesel engine exhaust gas) inlet, 11 is a clean gas outlet, 1
2 is a metal case, 13 is an ash outlet, 14 is an air inlet for burning particulates, 15 is a clean gas side space, 16 is a backwash valve, 17 is a bolt, and 18 is a packing. In this ceramics filter 6, the space between the dust-containing gas flow path and the clean gas flow path is partitioned by a filtration wall, the dust-containing gas flow path extends in the up-down direction, and the clean gas flow path extends in the horizontal direction. This is a cross-flow type filter.

FIG. 2 is an enlarged cross-sectional view of the mounting portion of the sealing material 2 of FIG. 1. In FIG. 2, 3 is a metal plate (in this example, the thickness is 0.6 mm, and the portion where the inorganic mat is mounted is shown. 1.4 cm width stainless steel plate (SUS30
Backbone of 4)), 3 'guard portion of the skeleton and integral, the inorganic mat (thickness of about 2.5 mm, weight 920 g / m ² Nipponpira_kogyo Co. pillar mat vermiculite containing about 20 wt% 4) 5 Is an inorganic mat composed of a laminated mat (a layer of the pillar mat, a thickness of about 7 mm, and a weight of about 15 mm).
It is a laminate with an alumina-silica ceramic fiber layer in which 00 g / m ² of Al ₂ O ₃ is 70% by weight). In FIG. 2, the ceramic filter side is a laminated mat 5, and a fiber layer 5 a made of silica and alumina (containing about 20% by weight of a binder) is pressed against the ceramic filter 6.

FIG. 3 is a system diagram of an example of a particulate trap device according to the present invention. In FIG. 3, 1a and 1b are particulate trap devices incorporating a ceramic filter, and 16a and 16b are backwash valves (solenoid valves). , 20
Is a diesel engine, 21 is a compressor for supplying compressed air for backwashing, 22 is an air tank, 23a, 23
b is a butterfly valve for an exhaust brake incorporated in a truck or the like. In this particulate trap apparatus, when backwashing and regenerating the 1a side, the butterfly valve 23a is closed, the backwash valve 16a is opened for a very short time (for example, 0.3 seconds), and then the butterfly valve 23a is opened. During the backwash regeneration of the 1a side, the exhaust gas of the diesel engine is purified by 1b and exhausted. When backwashing 1b is performed, the butterfly valve 23b is closed and the backwash valve 16b is opened for a very short time.

[0032]

Embodiment 1 The particulate trap device shown in FIG.
The particulate trap device assembled as shown in FIG. 3 was connected to a diesel engine, and the diesel engine displacement 6560 cc diesel engine output 120 PS / 2150 rpm diesel engine exhaust gas temperature 520-560 ° C. Filter (cross flow type) Dimensions 20 cm × 10 cm × 14cm Filter effective filtration area 2.1m ² (one side) Compressed air tank capacity 35 liters Compressed air tank pressure 7 atm Backwash interval of each filter 4 minutes Soot amount at engine outlet Bosch concentration 2 Sealing material Metal plate with SUS304 plate By operating the particulate trap apparatus under the condition of only the heat of the diesel engine exhaust gas at about 500 ° C. preheat treatment of the sealing material having the structure of FIG. 2 and a tightening pressure of about 5 kg / cm ^2, the following results were obtained.

In the case of the particulate trap apparatus using the sealing material having the structure shown in FIG. 2, after the total operation time of the intermittent operation is 300 hours, and after the lapse of 4,500 times in terms of the number of backwashing of each ceramic filter, No change was observed in the function of the sealing material, and the concentration of partial particulates in the clean gas flow path was measured.
(Particles were almost completely removed). After the test, the sealing material was observed, but no trace of particulate leakage was found on the surface of the sealing material.

[0034]

Comparative Example On the other hand, the same test was conducted using a conventional sealing material (a sealing material in which a commercially available heat-expandable mat having a thickness of about 6 mm and a weight of about 4070 g / m ² was wrapped with a quartz glass cloth). . 60 hours after the start of the operation, the concentration of the particulates in the exhaust gas in the clean gas flow path becomes Bosch concentration = 1.
(There is a clear leak). In addition, when the seal material was observed after the end of the test, it was recognized that particulates had adhered to the surface of the seal material exposed on the clean gas side.

[0035]

[Example 2] A sealing material was used, which was the same inorganic mat (pillar mat having a thickness of about 25 mm and a weight of about 920 g / m ² ) containing components that irreversibly expand when heated on both sides of a metal plate. When the same test as in Example 1 was performed, the durability until leakage was recognized was about twice as high as when the sealing material of Comparative Example was used.

[0036]

Example 3 A similar test was performed using a sealing material in which the skeleton made of the stainless steel plate in Example 1 was replaced with a skeleton made of an aluminum plate. Three times the durability was obtained.

[0037]

Embodiment 4 The metal casing side of the metal plate has a thickness of about 2.5.
mm, a pillar mat weight of about 920 g / m ^2, and the ceramic filter side having a thickness of about 7mm of the metal plate, as in Example 1 using a sealing material and the alumina-silica based ceramic fibers having a weight of about 1500 g / m ² When a similar test was performed, the durability was about 2.5 times that of the comparative example.

[0038]

In the particulate trap device of the present invention, the sealing material is provided with the inorganic mat on both sides of the hollow skeleton made of a flat metal plate, and at least one inorganic mat is irreversible when heated. Since a sealing material made of an inorganic mat containing a component that expands is used, it is easier to handle than a sealing material made of a flexible inorganic mat and quartz glass cloth. Therefore, the ceramic filter can be easily incorporated into the metal case via the sealing material. In addition, since the thermal conductivity of the metal plate is good, the expansion treatment of the inorganic mat by heat treatment after the ceramic filter is assembled is easy, the holding power of the ceramic filter is increased, and the durability of the sealing material is extended. .

Further, since a part of the skeleton of the metal plate is formed as a guard portion covering the surface of the inorganic mat in the clean gas side space of the ceramics filter, the surface of the inorganic mat can be protected from strong backwash gas flow. It is protected and can further increase the durability of the sealing material. In addition, the metal plate of the skeleton is made of a stainless steel plate having good heat resistance and corrosion resistance, and the inorganic mat attached to one side of the metal plate is composed of an inorganic fiber layer having good elasticity and a layer containing a component that irreversibly expands when heated. By using a laminated mat, the elasticity of the inorganic mat can be increased, and the holding function and sealing function of the ceramics filter can be maintained for a long time.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of a particulate trap device according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a sealing material part of FIG. 1;

FIG. 3 is a system diagram of an example of a particulate trap device according to the present invention.

FIG. 4 is an enlarged cross-sectional view of a sealing material portion of a conventional particulate trap device.

FIG. 5 is an enlarged sectional view of a sealing material portion of a conventional particulate trap device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Particulate trap device 2 Sealing material 3 Metal plate skeleton 3 'Guard part 4 Inorganic mat 5 Laminated mat 6 Ceramics filter 7 Backwashing means 8 Particulate receiving part 9 Sheath heater 10 Dust-containing gas inlet 11 Clean gas outlet 12 Metal case 13 Ash take-out port 14 Air inlet port 15 Clean gas side space 16 Backwash valve 17 Bolt 18 Packing

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeru Osaka Shigeru 1150 Hazawa-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Inside the Central Research Laboratory Asahi Glass Co., Ltd. Central Research Laboratory

Claims (9)

[Claims] 1. A pair of ceramic filters, each having a dust-containing gas flow passage and a clean gas flow passage defined by a filter wall, provided at a boundary between the dust-containing gas side space and the clean gas side space in a metal case. A backwash provided in the clean gas outflow part, which is retained in the metal case by the sealing material and intermittently generates a backwash gas flow that flows from the clean gas flow path side to the dust-containing gas flow path side through the filtration wall. A particulate trap device in which a ceramics filter is regenerated by means, in which an inorganic mat is attached to both sides of a skeleton made of a hollow frame-shaped metal plate in which the sealing material is on a plane, and at least one side of the skeleton is attached. The inorganic mat contains a component that expands irreversibly when heated, and the inorganic mat on one side of the metal plate is pressed against the edges of the opposing end faces of the ceramic filter. Ri, particulate trap apparatus inorganic mat in the other side of the metal plate, characterized in that it is pressed against the inner surface of the metal case. 2. An inorganic mat attached to both sides contains a component which irreversibly expands when heated, and a layer containing a component which irreversibly expands when heated on one side, and an inorganic fiber layer. The particulate trap device according to claim 1, wherein the particulate trap is a laminated mat. 3. The particulate trap device according to claim 1, wherein a part of the skeleton of the metal plate serves as a guard portion that covers the surface of the inorganic mat in the clean gas side space of the ceramics filter. 4. The particulate trap according to claim 1, 2 or 3, wherein the ceramics filter has a rectangular parallelepiped shape and has a channel in a direction in which the dust-containing gas channel and the clean gas channel intersect. apparatus. 5. An inorganic mat is attached to both sides of a skeleton made of a metal plate in the shape of a hollow frame on a plane, and the inorganic mat on at least one side contains a component that expands irreversibly when heated. Seal material. 6. The inorganic mats attached to both sides each contain a component that expands irreversibly when heated, and the inorganic mat on one side includes a layer containing a component that expands irreversibly when heated and an inorganic fiber layer. The sealing material according to claim 5, which is a laminated mat. 7. The sealing material according to claim 5, wherein the component that irreversibly expands when heated is vermiculite, and the inorganic mat contains 5 to 40% by weight of vermiculite. 8. The sealing material according to claim 5, wherein a part of the skeleton made of a metal plate serves as a guard portion for covering the surface of the inorganic mat attached to one surface of the metal plate. 9. The sealing material according to claim 5, 6, 7 or 8, wherein the metal plate is a stainless steel plate.