JPH10274029A - Exhaust gas purification device - Google Patents

Abstract

(57) [Summary] (with correction) [Problem] To provide a purification device having high purification performance of exhaust gas such as a diesel engine, and excellent in durability, economy and maintainability. SOLUTION: An electrode 12 is attached in the middle of an exhaust pipe 2, and one or two or more processing units 3 to 6 provided with at least one self-heating type high temperature heat resistant metal porous filter a to d for supplying electricity. With a particulate collection device,
An energizing device (power supply 1) for passing electricity to regenerate the filter
3) and, as means for detecting the filter regeneration time, a differential pressure gauge 7 for detecting a differential pressure between the exhaust gas introduction section 2A and the exhaust section 2B, and temperature sensors 8 to 1 for detecting the surface temperature of the filter.
1. At least one of a collection time measurement timer for measuring an elapsed time since the start of collection and a reproduction time measurement timer for measuring an elapsed time since the start of reproduction, and At least one energizing device is controlled based on a signal from at least one, and energizing control means (relay 14 and controller 15) for sequentially energizing the filter during regeneration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for treating particulates contained in exhaust gas from a diesel engine or the like.

[0002]

2. Description of the Related Art Diesel engines are widely used for transportation such as automobiles, general motive power, and power generators because of their high energy efficiency and excellent durability. , SOF, and sulfate, which is a major environmental problem.

As a countermeasure, transport engines such as automobiles have been improved in engines and fuel injection systems, so that particulates emitted from diesel engines can be reduced to some extent. However, since the reduction of the particulates by these methods is not yet sufficient, as a method of further reducing the particulates, an oxidation (combustion) catalyst is used, or the particulates are collected by a ceramic filter and then collected. A method of igniting with an electric heater, a burner, or the like, and propagating and burning with the combustion heat of the particulates themselves to remove them has been studied. In this method, a method is also used in which a ceramic filter is divided into a plurality of parts, and when the amount of trapped particulates exceeds a certain amount, the exhaust gas flow rate is reduced using a valve or the like, followed by regeneration.

On the other hand, in combustion devices such as stationary and industrial diesel engines, heating furnaces, cogeneration systems, heat pumps, boilers and the like, a method of using a dust collector such as a cyclone or a bag filter as an exhaust gas countermeasure has been adopted. .

[0005]

However, as described above, when the apparatus is divided into a plurality of parts and the amount of trapped particulates exceeds a certain amount, the flow rate of the exhaust gas is reduced using a valve or the like. In the method of regenerating a ceramic filter, there is a problem that the exhaust gas treatment device becomes complicated, such as the necessity of a device to drive the valve and its control device, and the accumulated particulates become hot when burning, so that the filter is eroded. Problem.

[0006] In the case of a ceramic filter, there is also a problem that ash contained in exhaust gas accumulates in the filter and cannot be used for a long time. On the other hand, a large amount of electric power is required to energize and regenerate the self-heating type filter or the catalyst-carrying self-heating type filter without reducing the exhaust gas flow rate using a valve or the like.

[0007] Dust collectors such as cyclones and bag filters used in stationary and industrial diesel engines can be installed only in places where the processing capacity is low, the equipment is expensive, or the temperature is low. There is such a problem.
Further, there is a problem that the collected carbon-based fine particles (particulates) must be disposed of. The present invention has been made to solve the above-mentioned conventional problems, and has an object to provide high purification performance of exhaust gas discharged from a diesel engine or the like, excellent durability, economic efficiency and the like. An object of the present invention is to provide an exhaust gas purifying apparatus which has good maintainability.

[0008]

In order to achieve the above object, the invention according to claim 1 has a structure in which an electrode is attached to a free end in an exhaust gas passage having an exhaust gas introduction portion and an exhaust portion. A particulate collection device comprising at least one self-heating type high-temperature heat-resistant metal porous filter that generates heat by passing electricity and one or two or more processing units arranged in parallel is provided. An energizing device that supplies electricity to the filter to regenerate the filter, and a differential pressure detecting unit that detects a differential pressure between the exhaust gas introduction unit and the exhaust unit as a unit that detects energization regeneration time of the filter. Temperature detecting means for detecting the surface temperature of the filter, the exhaust gas temperature of the exhaust gas introduction section, or the exhaust gas temperature of the exhaust section, and a lapse from the start of collection by the collection device. Based on a signal output from at least one of the collecting time measuring means for measuring the time and the reproducing time measuring means for measuring the elapsed time from the start of the reproducing, and at least one of the respective means. And an energization control unit that controls the energization device so that the filter is energized sequentially during regeneration, in addition to controlling the energization device.

According to a second aspect of the present invention, when the energization regeneration of the filter is started, when the differential pressure between the exhaust gas introduction section and the exhaust section becomes equal to or higher than a predetermined value by the differential pressure detecting means.
When the elapsed time from the start of collection by the time measuring means has reached a predetermined time, or when the differential pressure between the exhaust gas introduction section and the exhaust section has become a predetermined value or more by the differential pressure detection means or When the elapsed time from the start of collection by the collection time measuring means reaches a predetermined time, the detection is made by any one of the following methods.

According to a third aspect of the present invention, the end of energization regeneration of the filter is determined by measuring the regeneration time when the temperature of the filter surface or the exhaust gas temperature at the exhaust / exhaust section is equal to or higher than a predetermined value. When the elapsed time from the start of the regeneration by the means has reached a predetermined time, when the temperature of the filter surface or the exhaust gas temperature at the exhaust / exhaust section has exceeded a predetermined value by the temperature detection means, or when the regeneration time measurement means And when the elapsed time from the start of the reproduction has reached a predetermined time, it is detected by any one of them.

According to a fourth aspect of the present invention, the energization control means controls the amount of energization based on a function of controlling the amount of energization to the filter or a surface temperature of the filter or an exhaust gas temperature at an exhaust gas introduction portion or an exhaust portion. Variably controlled. The invention according to claim 5 is characterized in that the self-heating type high-temperature heat-resistant metal porous filter comprises:
It is a catalyst-carrying self-heating type high-temperature heat-resistant metal porous filter carrying a catalyst.

The operation of the present invention will be described. In the middle of an exhaust gas passage having an exhaust gas introduction section and an exhaust section,
A configuration in which an electrode is attached to a free end, wherein at least one self-heating type high temperature heat-resistant metal porous filter or a catalyst-carrying self-heating type high temperature heat-resistant metal porous filter that generates heat by passing electricity is provided. An exhaust gas purification device is obtained by interposing a particulate collection device including two or more processing units in parallel or in parallel.

When the self-heating type high temperature heat-resistant metal porous filter or the catalyst-carrying self-heating type high temperature heat-resistant metal porous filter is installed in the container of the processing unit, one self-heating type high temperature heat-resistant metal is used in one container. A porous filter or a catalyst-carrying self-heating high-temperature-resistant metal porous filter may be installed, or a plurality of self-heating-type high-temperature-resistant metal porous filters or a catalyst-carrying self-heating high-temperature-resistant metal in one container. A method of installing a porous filter may be adopted.

Further, the shape of the self-heating type high-temperature resistant metal porous filter or the catalyst-carrying self-heating type high-temperature resistant metal porous filter installed in the container is not limited. Here, when particulates in exhaust gas of a diesel engine are processed using the exhaust gas purifying apparatus of the present invention, for example, a self-heating type high-temperature heat-resistant metal porous filter or a catalyst-carrying self-heating type after a certain period of time has elapsed. The particulates are collected by the high-temperature heat-resistant metal porous filter, and the differential pressure between the exhaust gas introduction part and the exhaust part of the collection device increases. At that time, electricity was directly applied to the filter itself from one free-end electrode of the self-heating type high temperature heat-resistant metal porous filter or the catalyst-carrying self-heating type high temperature heat-resistant metal porous filter, and collected. Burn off particulates. At this time, it is also possible to energize two or more of the self-heating type high temperature heat-resistant metal porous filter or the catalyst-carrying self-heating type high temperature heat-resistant metal porous filter at the same time.

[0015] Thus, the collected particulates can be processed without applying a large amount of electric power to energize the entire filter. Further, since the filter or the catalyst itself is energized, the filter or the catalyst can generate heat uniformly. Therefore, no unburned particulates are generated, and the durability of the filter is increased. In addition, when the catalyst is carried, the temperature at which the catalyst can be burned and removed can be lowered, so that the amount of electric power supplied to the filter can be reduced.

Furthermore, the filter can be designed so that the filter pore size and porosity are arbitrarily changed so that the filter is not blocked by ash. In the apparatus of the present invention, the energization regeneration time of the filter is detected, and the energization of the filter is controlled based on the timing. In this case, as means for detecting the energization regeneration time of the filter, a differential pressure detecting means for detecting a differential pressure between the exhaust gas introduction part and the exhaust part, a temperature detection means for detecting a surface temperature of the filter, and a collection by the collection device At least one of a collecting time measuring means for measuring an elapsed time from the start of the reproduction and a reproducing time measuring means for measuring an elapsed time from the start of the reproduction, and at least one of the respective means Power supply control means for controlling the power supply device based on the signal output from the power supply device and controlling the power supply device so that power is sequentially supplied to the filter during regeneration.

More specifically, the start of energization regeneration of the filter is performed by the time measuring means when the differential pressure between the exhaust gas introduction part and the exhaust part becomes a predetermined value or more by the differential pressure detecting means. When the elapsed time from the start of the predetermined time, when the differential pressure between the exhaust gas introduction unit and the exhaust unit is equal to or more than a predetermined value by the differential pressure detection means, or by the collection time measurement means When the elapsed time from the start of collection reaches a predetermined time, it is detected by any one of them.

When the filter surface temperature or the exhaust gas temperature at the exhaust gas discharge section becomes equal to or higher than a predetermined value by the temperature detecting means, the regeneration is started by the regeneration time measuring means. When the elapsed time after the predetermined time has reached a predetermined time, when the filter surface temperature or the exhaust gas temperature at the exhaust gas discharge section has become equal to or higher than a predetermined value by the temperature detecting means, or the regeneration is started by the regeneration time measuring means. When the elapsed time has reached a predetermined time, it is detected by one of them.

Further, the self-heating type high temperature heat-resistant metal porous filter or the catalyst-carrying self-heating type high temperature heat-resistant metal porous filter which is divided into a plurality of pieces can be used as one self-heating type. After the regeneration of the heat-generating high-temperature heat-resistant metal porous filter or the catalyst-carrying self-heating-type high-temperature heat-resistant metal porous filter is completed, when the pressure difference before and after the apparatus becomes equal to or higher than a predetermined value or for a predetermined time, When the time has elapsed, a method of repeating a process of regenerating another filter may be used.

Even if the power supply device is a device for fixing the amount of power supply, the amount of power supplied by PI control, PID control, or the like using the surface temperature of the filter, the exhaust gas temperature at the exhaust gas inlet or outlet, or the like. May be variably controlled. At this time, it is also possible to adopt a method of setting the maximum amount of power and limiting the amount of power when energized.

In the exhaust gas purifying apparatus of the present invention, a self-heating type high temperature heat-resistant metal porous filter or a catalyst-carrying self-heating type high temperature heat-resistant metal porous filter is used without utilizing the propagation combustion caused by particulate combustion. Because the filter is heated directly and uniformly to burn off particulates, regeneration can be started without being affected by the amount of collected particulates.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described in more detail. The self-heating type high-temperature heat-resistant metal porous filter of the present invention is manufactured by attaching an electrode to a free end of a porous metal body having a resistance heating property. In addition, a catalyst-carrying self-heating type high temperature and heat resistant metal porous filter is produced by supporting a catalyst on this self-heating type high temperature and heat resistant metal porous filter.

The lower limit of the average pore diameter of the above porous metal body is 1
It is 0 μm, preferably 20 μm, while its upper limit is 500 μm, preferably 200 μm. In the present invention, if the average pore diameter of the porous metal body is less than 10 μm, the pressure difference may increase, or the pores may be blocked by ash in the exhaust gas. Each of them is not preferable because the collection efficiency of particulates decreases.

The porosity and thickness of the porous metal body of the present invention are arbitrary, and can be designed so that the pores are not blocked by ash in the exhaust gas. The porous metal body of the present invention may be any material having resistance to heat generation when energized, and its material is arbitrary. Usually, one or more metals selected from Fe, Cr, Ni, Co, and W are used. The main material is preferably used. Further, it is more preferable to contain a metal such as Al, Si, and Ti.

For example, a Kanthal material such as Fe-Cr-Al or a nickel-chromium material can be used, and more preferably, a Fe-Cr-Al-REM material can be used. Specifically, in the case of Fe-Cr-Al-REM-based materials, Cr is 15 to 23% by weight, Al is 2.5 to 6.0, and REM is L.
One, two or more of a, Y, and Ce are used, and the added amount is 0.02 to 1%. Other components may contain unavoidable components.

The method for producing the above-described porous metal body is also optional. Specifically, for example, a) Fe, Cr, Ni, C
o, one or two or more selected from metal powder, short fiber, long fiber, whisker, etc. made from a metal whose main material is selected from one selected from the group consisting of W and W, or mixed with a resin binder. Sintering after molding by injection molding, extrusion molding, flow molding, etc., b) Fe, C
a method of mixing and sintering a metal mainly composed of one selected from the group consisting of r, Ni, Co, and W with a substance that is vaporized by high temperature or a chemical reaction, c) selected from Fe, Cr, Ni, Co, and W A method of depositing a porous body using a plating solution containing ions of a metal having one as a main material, d) Fe,
A method of forming and heat-treating porous particles made of a metal mainly composed of one selected from Cr, Ni, Co and W, e) F
e, an alloy prepared by mixing or depositing a metal that is one of the main materials selected from e, Cr, Ni, Co, and W and that is easily dissolved or easily diffuses in the metal, and then the metal is removed. F) One or two or more metals mainly composed of one selected from the group consisting of Fe, Cr, Ni, Co, and W are added to a porous body made of a combustible substance, a soluble substance, or the like.
A method of coating by plating or vapor-depositing a layer or two or more layers, burning and dissolving and removing the substance at the time of sintering to form a porous body, and further, adding one or more of the above metals to the porous body. A method of coating by plating or vapor deposition. G) Injecting plaster or a fluid molding mold material for precision casting into a porous body made of a flammable substance or a soluble substance, firing and producing a porous mold. 1 selected from Fe, Cr, Ni, Co, W
One or two or more of the methods of injecting and solidifying and bonding a molten or powdered fluid of a metal as a main material can be used.

In the self-heating type high temperature heat-resistant metal porous filter and the catalyst-carrying self-heating type high temperature heat-resistant metal porous filter of the present invention, an electrode is attached to a free end thereof to supply power to the porous metal body. The material of the electrode is arbitrary, for example, Cu, stainless steel or the like can be used, but it is preferable to use the same material as the porous metal body.

In the porous metal body of the present invention, in order to further impart heat resistance and corrosion resistance, the surface thereof is made of Cr oxide,
It is preferable to coat with one or two or more kinds of Al oxide, Si oxide and Ti oxide. The method of coating these oxides on the surface of the porous metal body is optional. Specifically, for example, the metal porous body is made of Cr, Al,
In the case of containing one or more kinds of metals selected from Si and Ti, the porous metal body is placed in an oxidizing atmosphere such as air at 500 to 1200 ° C., preferably 600 to 1200 ° C.
By performing the oxidizing heat treatment at 00 ° C., an oxide film of such a metal can be easily formed on the surface.

When coating the surface of the porous metal with these oxides, it is preferable that the step of attaching an electrode to the free end of the porous metal is performed before the coating. As a preferable method as a method for producing the metal porous body of the present invention, for example, from a metal having heat generation,
A method in which metal fibers are manufactured by a drawing method, a melt spinning method, a wire cutting method, a coil material cutting method, a chatter vibration cutting method, a coating method, a whisker method, or the like, and formed into a filter shape can be used.

At this time, the lower limit of the average diameter of the metal fiber is 5 μm, preferably 10 μm, while the upper limit is desirably 500 μm, preferably 100 μm. If the average diameter of the metal fibers is less than 5 μm, the pressure difference may increase, or pores may be blocked by ash in the exhaust gas. On the other hand, if the average diameter exceeds 500 μm, particulates in the exhaust gas may be trapped. Efficiency may be reduced.

At this time, the lower limit of the porosity of the filter is 30%, preferably 70%, while the upper limit is desirably 95%, preferably 93%.
If the porosity of the filter is less than 30%, the pressure difference may increase or the pores may be blocked by ash in the exhaust gas, while if it exceeds 95%, particulates in the exhaust gas may be trapped. The collection efficiency may be reduced.

Preferably, the metal fiber filter is further subjected to a sintering process. Conditions for the sintering treatment are arbitrary, but specifically, for example, in a vacuum or non-oxidizing atmosphere, at 800 to 1500 ° C., preferably 900 to 13 ° C.
In the range of 00 ° C, 10 minutes to 10 hours, preferably 1 minute
It is performed by heating for 6 hours. It is also preferable to apply a load during sintering.

Further, it is also preferable to apply a heat treatment after sintering the metal fiber filter to form a coating film of a metal oxide on the surface of the metal fiber filter, thereby imparting high-temperature heat resistance and corrosion resistance to the metal fiber filter. is there. The conditions of the heat treatment are also arbitrary, but specifically, for example, in an oxidizing atmosphere such as air, at 600 to 1200 ° C., preferably 800 to 1200 ° C.
In the range of 1100 ° C for 1 to 20 hours, preferably 2 hours
Heating is performed for 10 to 10 hours.

The above-mentioned porous metal body may be processed into a corrugated or irregular shape simultaneously with or after sintering. This is because, when the filter is processed into a corrugated or irregular shape, the mechanical strength of the filter is improved, and the surface area per volume is increased. The catalyst-carrying self-heating type high-temperature heat-resistant metal porous filter of the present invention can be obtained by supporting a catalyst on the above-described porous metal body.

This catalyst is supported by connecting an electrode to the free end of the porous metal body and, if necessary, treating the surface of the porous metal body with Cr oxide, Al oxide,
It is preferably performed after coating with one or more oxide compounds of oxides and Ti oxides. This is because if the catalyst is supported before the electrode is connected, the catalyst enters between the metal porous body and the electrode and becomes a resistance when energized, and generates heat, so that the metal porous body is melted or disconnected.

Further, by coating the surface of the porous metal body with one or more oxidized compounds of Cr oxide, Al oxide, Si oxide and Ti oxide, the supportability of the catalyst is improved. be able to. The catalyst carrier is not particularly limited, but alumina, silica, zirconia, titania, ZSM-5, USY, SAPO, zeolites such as Y-type zeolite, silica-alumina, alumina-zirconia, alumina-titania, silica At least one selected from titania, silica-zirconia, and titania-zirconia is preferred.

The average particle size of the catalyst carrier particles is arbitrary, but the lower limit is usually 0.01 μm, preferably
It is 0.1 μm, while its upper limit is desirably 20 μm, preferably 10 μm. When the average particle diameter of the catalyst carrier particles is less than 0.01 μm, there is a great difficulty in the production. On the other hand, when the average particle diameter exceeds 20 μm, the pores of the porous metal body may be closed, or peeling from the porous metal body may easily occur. There is.

The catalytically active metal component supported on the catalyst carrier is optional, but usually, Pt, Pd, Cu, K, Rb, C
s, Mo, Cr, Mn, Rh, Ag, Ba, Ca, Z
One or two or more metals selected from r, Co, Fe, La, and Ce are preferable, and Pt, Pd, R
1 selected from h, Cu, K, Mo, Mn, Fe, Ce
More preferably, it is a species or two or more metals.

Further, in the present invention, as the catalytically active metal component supported on the catalyst carrier, (A) Cu is preferred because it is low in poisoning by sulfur oxide contained in exhaust gas and excellent in flammability of particulates. , (B) K, and (C) Mo and / or V in combination.

These catalytically active metal components may be used as such in the form of a metal, or a halide, such as an oxide, carbonate, nitrate or bromide, a carboxylate, a sulfate, a sulfite, a phosphate or a complex acid salt. Used in such forms. The amount of these metals or metal compounds supported on the catalyst carrier is also arbitrary, but usually, the amount of each metal or metal compound is converted into the amount of each carrier.
The lower limit per g is 0.01 g, preferably 0.0 g.
5 g, while the upper limit is desirably 2.0 g, preferably 1.0 g. If the amount of metal supported is less than 0.01 g per 1 g of the carrier, the activity of the catalyst may not be exhibited. On the other hand, if it exceeds 2.0 g, the porous metal may be blocked. is there.

The method for supporting the catalyst carrier and the catalyst on the porous metal body is not limited, but a method such as a wash coat method, an impregnation method, and a spray method using a nozzle can be used. . After supporting the catalyst under such conditions, for example, 80 to 200 ° C., preferably 10 to 200 ° C.
Dry at 0 to 130 ° C., and further, for example, 300 to 10
By baking at 00 ° C, preferably 500 to 800 ° C, the catalyst-carrying self-heating high-temperature-resistant metal porous filter of the present invention can be obtained.

Here, as described above, the electrode is attached to the free end in the middle of the exhaust gas passage having the exhaust gas introduction portion and the exhaust portion. Through a particulate collection device comprising one or two or more parallel processing units provided with at least one heat-resistant metal porous filter or a catalyst-carrying self-heating type high temperature heat-resistant metal porous filter carrying a catalyst. To obtain an exhaust gas purification device.

When the self-heating type high-temperature heat-resistant metal porous filter or the catalyst-carrying self-heating type high-temperature heat-resistant metal porous body is installed in the container of the processing unit, one self-heating-type high-temperature heat resistance A metal porous filter or a catalyst-carrying self-heating high-temperature heat-resistant metal porous filter may be installed, or a plurality of self-heating-type high-temperature heat-resistant metal porous filters or a catalyst-carrying self-heating high-temperature resistance in a single container. A method of installing a metal porous filter may be used.

When a self-heating type high temperature heat-resistant metal porous filter or a catalyst-carrying self-heating type high temperature heat-resistant metal porous filter is installed in a container, the shape thereof is not limited. The exhaust gas purifying apparatus of the present invention includes a particulate trapping device comprising the above-described processing unit, a power supply, various sensors as various detecting means, a power supply controlling means, and the like.

When the particulates in the exhaust gas of a diesel engine are treated using the exhaust gas purifying apparatus of the present invention, a self-heating type high temperature heat-resistant metal porous filter or a catalyst-carrying self-heating type high temperature The particulates are collected by the heat-resistant metal porous filter, and the differential pressure between the exhaust gas introduction part and the exhaust part of the collection device increases. At that time, electricity was directly applied to the filter itself from one free-end electrode of the self-heating type high temperature heat-resistant metal porous filter or the catalyst-carrying self-heating type high temperature heat-resistant metal porous filter, and collected. Burn off particulates. At this time, it is also possible to energize two or more of the self-heating type high temperature heat-resistant metal porous filter or the catalyst-carrying self-heating type high temperature heat-resistant metal porous filter at the same time.

As a result, the collected particulates can be processed without applying a large amount of electric power to energize the entire filter. Further, since the filter or the catalyst itself is energized, the filter or the catalyst can generate heat uniformly. Therefore, no unburned particulates are generated, and the durability of the filter is increased. In addition, when the catalyst is carried, the temperature at which the catalyst can be burned and removed can be lowered, so that the amount of electric power supplied to the filter can be reduced.

Further, the filter can be designed so that the filter is not blocked by ash by arbitrarily changing the pore size and porosity of the self-heating type high temperature heat resistant metal porous filter. In the apparatus of the present invention, the energization regeneration time of the filter is detected, and the energization to the filter is controlled based on the timing.

In this case, as means for detecting the energization regeneration time of the filter, a differential pressure detecting means for detecting a differential pressure between the exhaust gas introduction section and the exhaust section, a surface temperature of the filter or an exhaust gas temperature or exhaust gas of the exhaust gas introduction section. Temperature detection means for detecting the exhaust gas temperature in the section, collection time measurement means for measuring the time elapsed since the start of collection by the particulate collection device, and regeneration for measuring the time elapsed since the start of the regeneration At least one of each means of the time measuring means,
An energization control means for controlling the energization device based on a signal output from at least one of the means, and for controlling the energization device so that the filter is energized sequentially during regeneration. .

Even if the current supply device is a device for fixing the amount of current supply, PI control and PID control are performed using the surface temperature of the filter, the exhaust gas temperature at the exhaust gas inlet and outlet, and the like.
A device that variably controls the amount of electric power to be supplied by control or the like may be used. At this time, it is also possible to adopt a method of setting the maximum amount of power and limiting the amount of power when energized.

Here, the structure for detecting the energization regeneration time of the filter is specifically as follows. In other words, the start time of the energization regeneration of the filter is the time elapsed from the start of collection by the time measuring means when the differential pressure between the exhaust gas introduction part and the exhaust part becomes a predetermined value or more by the differential pressure detecting means. When the time reaches a predetermined time, when the differential pressure between the exhaust gas introduction unit and the exhaust unit becomes equal to or more than a predetermined value by the differential pressure detection unit, or after the collection is started by the collection time measurement unit. When the elapsed time has reached the predetermined time, it is detected by any one of them.

When the filter surface temperature or the exhaust gas temperature at the exhaust gas discharge section becomes equal to or higher than a predetermined value by the temperature detecting means, the regeneration is started by the regeneration time measuring means. When the elapsed time after the predetermined time has reached a predetermined time, when the filter surface temperature or the exhaust gas temperature at the exhaust gas discharge section has become equal to or higher than a predetermined value by the temperature detecting means, or the regeneration is started by the regeneration time measuring means. When the elapsed time has reached a predetermined time, it is detected by one of them.

The self-heating type high-temperature heat-resistant metal porous filter or the catalyst-carrying self-heating type high-temperature heat-resistant metal porous filter which is divided into a plurality of pieces can be used as one self-heating type. After the regeneration of the heat-generating high-temperature heat-resistant metal porous filter or the catalyst-carrying self-heating-type high-temperature heat-resistant metal porous filter is completed, when the pressure difference before and after the apparatus becomes equal to or higher than a predetermined value or for a predetermined time, When the time has elapsed, a method of repeating a process of regenerating another filter may be used.

In the exhaust gas purifying apparatus of the present invention, a current is directly supplied to the self-heating type high temperature heat-resistant metal porous filter or the catalyst-carrying self-heating type high temperature heat-resistant metal porous filter without utilizing the propagation combustion due to the combustion of particulates. Therefore, regeneration can be started without being affected by the amount of collected particulates because the filter is directly and uniformly heated to burn and remove the particulates.

FIG. 1 is a view showing an embodiment of an exhaust gas purifying apparatus according to the present invention. Note that the exhaust gas purifying apparatus according to the present invention is not limited to this embodiment. In this figure, 1 is a diesel engine, 2 is an exhaust pipe, 3
6 are processing units interposed in parallel with the exhaust pipe 2, and 7 is an exhaust gas introduction section 2A and an exhaust section 2B of the exhaust pipe 2.
, A pressure sensor for detecting the surface temperature of the filters a to d provided in each of the processing units 3 to 6, and 12 at the free end of each of the filters a to d. Attached electrodes, 13 is power supply, 14 is power supply 1
A relay 15 interposed between 3 and each electrode 12 is a controller.

The power supply 13 constitutes an energizing device of the present invention, and the relay 14 and the controller 15 constitute energizing control means of the present invention. Further, the controller 15 is provided with a timer function as a trapping time measuring means and a reproducing time measuring means according to the present invention. On the other hand, FIG.
Indicates the configuration of the processing units 3 to 6. In this example, a plurality of filters 16 are provided in parallel in a container 19, and an insulating material and a packing 17 as a heat insulating material are provided between the filters 16. Is interposed. Reference numeral 18 denotes an electrode provided at a free end of the filter 16.

When a plurality of filters 16 are provided in parallel in the processing units 3 to 6 as described above, a relay for switching the power supply to each filter 16 is provided in addition to the relay 14 shown in FIG. It is provided every 3-6.
The arrows in FIG. 2 indicate the flow of the exhaust gas. As shown by the arrows, the exhaust gas introduced from the exhaust gas introduction section flows into the center of each filter 16 and
Through the side wall of the vehicle to the exhaust gas discharge section.

Next, specific examples of the self-heating type high temperature heat-resistant metal porous filter and the catalyst-carrying self-heating type high temperature heat-resistant metal porous filter according to the present invention will be described. (Example 1) Cr: 20.02%, Al: 4.9% La: 0.08
%, High-temperature-resistant metal fibers having a cross section of 50 × 15 μm and cut to a length of 70 mm from a high-temperature-resistant metal composed of high-temperature-resistant metal consisting of Fe and unavoidable impurities so that the porosity is 85%. To form a high-temperature heat-resistant metal porous body.

This high-temperature heat-resistant metal porous body was 25 mm wide,
After being formed into a shape having a length of 800 mm, after sintering at 1100 ° C. for 2 hours under an inert gas atmosphere, electrodes made of stainless steel were attached to both ends, and then at 1000 ° C.
Heat treatment was performed for 6 hours to precipitate alumina on the surface, thereby obtaining a self-heating type high-temperature heat-resistant metal porous filter. Four processing units (processing units 3 to 6 in FIG. 1) each including one self-heating type high-temperature heat-resistant metal porous filter disposed in a container are installed so that the relationship with respect to the exhaust gas flow is parallel. A particulate collection device was formed.

The particulate trapping device was interposed in the middle of an exhaust pipe constituting an exhaust passage of a diesel engine. The diesel engine was operated at a constant load of 70%, and the exhaust gas having a black smoke concentration of 8% was passed through the particulate trap with a Bosch smoke meter.

After 10 minutes from the start of collection, energization of the self-heating type high temperature and heat resistant metal porous filter a of the processing unit 3 was started using an energizing device. At this time, the surface temperature of the self-heating type high temperature heat resistant metal porous filter a was measured by the temperature sensor 8 as a temperature detecting means, and the maximum temperature was 6
At 10 ° C., energization regeneration was performed while adjusting the amount of power by PI control. At this time, the lowest value of the electric energy is 1
It was set to 500W. Surface temperature of filter a is 600 °
When it became C, the energization of the filter a was terminated. After 10 minutes from the start of energization of the filter a,
The energization regeneration of the filter b of the next processing unit 4 is started,
Regeneration was performed in the same manner as in the filter a. This operation was repeated in the order of all the filters a to d.

At this time, the changes over time in the differential pressure between the exhaust gas inlet and outlet of the particulate trapping device, the surface temperature of the filters a to d, and the amount of power supplied to the filters a to d were measured. (See FIGS. 3A to 3E). The black smoke concentration at the exhaust gas inlet and outlet of the particulate trap was measured, and the average black smoke removal rate was calculated.
%Met.

In FIG. 3 and FIGS. 4 to 8 to be described later, the diagram A shows the filter surface temperature, and the diagram B shows the electric energy. (Example 2) Cr: 20.02%, Al: 4.9% La: 0.08
%, High-temperature-resistant metal fibers having a cross section of 50 × 15 μm and cut to a length of 70 mm from a high-temperature-resistant metal composed of high-temperature-resistant metal consisting of Fe and unavoidable impurities so that the porosity is 85%. To form a high-temperature heat-resistant metal porous body.

This high-temperature heat-resistant metal porous body was 25 mm wide,
After being formed into a shape having a length of 800 mm, after sintering at 1100 ° C. for 2 hours under an inert gas atmosphere, electrodes made of stainless steel were attached to both ends, and then at 1000 ° C.
Heat treatment was performed for 6 hours to precipitate alumina on the surface, thereby obtaining a self-heating type high-temperature heat-resistant metal porous filter. Then, 7 g of titania particles were added to 3.8 g of copper nitrate trihydrate, and potassium nitrate was added.
The mixture was mixed with 200 ml of an aqueous solution prepared from 2.6 g of ammonium molybdate tetrahydrate 1.8 g, and the mixed solution was stirred to evaporate water and dried at 110 ° C.
It was calcined at ° C to prepare a catalyst. 10 g of the catalyst was mixed with 90 ml of a 99% ethanol solution, and the mixture was pulverized and mixed with a ball mill for 24 hours to prepare a catalyst slurry. Wash the slurry onto a filter and apply 110 °
After drying at C for 1 hour, the operation of baking at 500 ° C. for 2 hours was repeated until 50 mg of catalyst particles were supported per 1 g of the filter to obtain a catalyst-carrying self-heating type high-temperature resistant metal porous filter.

The four processing units (the processing units 3 to 6 in FIG. 1) each having one catalyst-supporting self-heating type high-temperature heat-resistant metal porous filter disposed in a container have a parallel relationship with respect to the exhaust gas flow. And a particulate collection device was formed. Then, the particulate trapping device was interposed in the middle of an exhaust pipe constituting an exhaust passage of a diesel engine. Load 70 diesel engine
Exhaust gas with a black smoke concentration of 8% was passed through the particulate trap with a Bosch smoke meter.

Fifteen minutes after the start of collection, energization of the self-heating type high temperature and heat resistant metal porous filter a of the processing unit 3 was started using an energizing device. At this time, the surface temperature of the self-heating type high temperature heat resistant metal porous filter a was measured by the temperature sensor 8 as a temperature detecting means, and the maximum temperature was 5
At a temperature of 60 ° C., energization regeneration was performed while adjusting the amount of power by PI control. At this time, the lowest value of the electric energy is 15
It was set to 00W. Surface temperature of filter a is 550 ° C
, The power supply to the filter a was terminated.
Fifteen minutes after the start of energization of the filter a, the energization regeneration of the next filter b was started, and regeneration was performed in the same manner as the previous filter a. This operation was repeated in the order of all the filters a to d.

At this time, the time-dependent changes in the differential pressure between the exhaust gas inlet and the outlet of the particulate trap, the surface temperature of the filters a to d, and the amount of power supplied to the filters a to d are measured. (See FIGS. 4A to 4E). The black smoke concentration at the exhaust gas inlet and outlet of the particulate trap was measured, and the average black smoke removal rate was calculated.
3%. (Example 3) Cr: 20.02%, Al: 4.9%, La: 0.
A cross section made by coil cutting from a high-temperature heat-resistant metal consisting of 08%, balance Fe and unavoidable impurities, 50 × 15 μm
The high-temperature heat-resistant metal fiber was cut into a length of 70 mm, and collected in a filter shape so as to have a porosity of 85% to produce a high-temperature heat-resistant metal porous body.

This high-temperature heat-resistant metal porous body was 25 mm wide,
After being formed into a shape having a length of 800 mm, after sintering at 1100 ° C. for 2 hours under an inert gas atmosphere, electrodes made of stainless steel were attached to both ends, and then at 1000 ° C.
Heat treatment was performed for 6 hours to precipitate alumina on the surface, thereby obtaining a self-heating type high-temperature heat-resistant metal porous filter. Four processing units (processing units 3 to 6 in FIG. 1) each including one self-heating type high-temperature heat-resistant metal porous filter disposed in a container are installed so that the relationship with respect to the exhaust gas flow is parallel. A particulate collection device was formed.

Then, the particulate trapping device was interposed in the middle of an exhaust pipe constituting an exhaust passage of a diesel engine. The diesel engine was operated at a constant load of 70%, and the exhaust gas having a black smoke concentration of 8% was passed through the particulate trap with a Bosch smoke meter.

Ten minutes after the start of collection, 1000 W of electric power was applied to the self-heating type high temperature and heat resistant metal porous filter a of the processing unit 3 using an energizing device. At that time, the surface temperature of the self-heating type high temperature heat resistant metal porous filter a was measured by a temperature sensor 8 as a temperature detecting means,
When the temperature reached 600 ° C., the power supply to the filter a was terminated. After 10 minutes from the start of energization of the filter a, energization regeneration of the next filter b was started, and regeneration was performed in the same manner as the previous filter a. This operation was repeated in the order of all the filters a to d.

At this time, the time-dependent changes in the differential pressure between the exhaust gas inlet and the outlet of the particulate trapping device, the surface temperatures of the filters a to d, and the amount of power supplied to the filters a to d are measured. (See FIGS. 5A to 5E). The black smoke concentration at the exhaust gas inlet and outlet of the particulate trap was measured, and the average black smoke removal rate was calculated.
6%. (Example 4) Cr: 20.02%, Al: 4.9%, La: 0.
A cross section made by coil cutting from a high-temperature heat-resistant metal consisting of 08%, balance Fe and unavoidable impurities, 50 × 15 μm
The high-temperature heat-resistant metal fiber was cut into a length of 70 mm, and collected in a filter shape so as to have a porosity of 85% to produce a high-temperature heat-resistant metal porous body.

This high-temperature heat-resistant metal porous body was 25 mm wide,
After being formed into a shape having a length of 800 mm, after sintering at 1100 ° C. for 2 hours under an inert gas atmosphere, electrodes made of stainless steel were attached to both ends, and then at 1000 ° C.
Heat treatment was performed for 6 hours to precipitate alumina on the surface, thereby obtaining a self-heating type high-temperature heat-resistant metal porous filter. Four processing units (processing units 3 to 6 in FIG. 1) each including one self-heating type high-temperature heat-resistant metal porous filter disposed in a container are installed so that the relationship with respect to the exhaust gas flow is parallel. A particulate collection device was formed.

Then, the particulate trapping device was interposed in the middle of an exhaust pipe constituting an exhaust passage of a diesel engine. The diesel engine was operated at a constant load of 70%, and the exhaust gas having a black smoke concentration of 8% was passed through the particulate trap with a Bosch smoke meter.

When the differential pressure between the exhaust gas introduction part and the exhaust part of the particulate trap becomes 200 mmH ₂ O,
Energization was started using an energization device. At this time, the surface temperature of the self-heating type high temperature heat resistant metal porous filter a was measured by the temperature sensor 8 as a temperature detecting means, and the maximum temperature was 6
While setting the temperature to 10 ° C and adjusting the amount of power with PI control,
The energization regeneration was performed. At this time, the lowest value of the electric energy is 1500
W was set.

When the surface temperature of the filter a reached 600 ° C., the power supply to the filter a was terminated. Next, when the differential pressure between the exhaust gas introduction part and the exhaust part of the particulate collection device becomes 200 mmH ₂ O, the next filter b
And the regeneration was started in the same manner as in the previous filter a. This operation was repeated in the order of all the filters a to d.

At this time, the time-dependent changes in the differential pressure between the exhaust gas introduction part and the exhaust part of the particulate collection device, the surface temperature of the filters 1-4, and the amount of power supplied to the filters a-d are measured. (See FIGS. 6A to 6E). The black smoke concentration at the exhaust gas inlet and outlet of the particulate trap was measured, and the average black smoke removal rate was calculated.
3%. (Example 5) Cr: 20.02%, Al: 4.9%, La: 0.2%
A cross section made by coil cutting from a high-temperature heat-resistant metal consisting of 08%, balance Fe and unavoidable impurities, 50 × 15 μm
The high-temperature heat-resistant metal fiber was cut into a length of 70 mm, and collected in a filter shape so as to have a porosity of 85% to produce a high-temperature heat-resistant metal porous body.

This high-temperature heat-resistant metal porous body was 25 mm wide,
After being formed into a shape having a length of 800 mm, after sintering at 1100 ° C. for 6 hours under an inert gas atmosphere, electrodes made of stainless steel were attached to both ends, and then at 1000 ° C.
Heat treatment was performed for 6 hours to precipitate alumina on the surface, thereby obtaining a self-heating type high-temperature heat-resistant metal porous filter. Four processing units (processing units 3 to 6 in FIG. 1) each including one self-heating type high-temperature heat-resistant metal porous filter disposed in a container are installed so that the relationship with respect to the exhaust gas flow is parallel. A particulate collection device was formed.

Then, the particulate collecting device was interposed in the middle of an exhaust pipe constituting an exhaust passage of a diesel engine. The diesel engine was operated at a constant load of 70%, and the exhaust gas having a black smoke concentration of 8% was passed through the particulate trap with a Bosch smoke meter.

When the differential pressure between the exhaust gas introduction part and the exhaust part of the particulate trap becomes 200 mmH ₂ O,
An electric power of 1000 W was applied to the self-heating type high temperature and heat resistant metal porous filter a of the processing unit 3 using an energizing device. At this time, the surface temperature of the self-heating type high-temperature heat-resistant metal porous filter a was measured by the temperature sensor 8 as a temperature detecting means.
The power supply to was terminated. Next, when the differential pressure between the exhaust gas introduction part and the exhaust part of the particulate collection device became 200 mmH ₂ O, the energization regeneration of the next filter b was started, and the regeneration was performed in the same manner as the previous filter a. . This operation was repeated in the order of all the filters a to d.

At this time, the changes over time in the pressure difference between the exhaust gas inlet and the outlet of the particulate trapping device, the surface temperature of the filters a to d, and the amount of power supplied to the filters a to d were measured. (See FIGS. 7A to 7E). The black smoke concentration at the exhaust gas inlet and outlet of the particulate trap was measured, and the average black smoke removal rate was calculated.
%Met. (Example 6) Cr: 20.02%, Al: 4.9%, La: 0.02%
A cross section made by coil cutting from a high-temperature heat-resistant metal consisting of 08%, balance Fe and unavoidable impurities, 50 × 15 μm
The high-temperature heat-resistant metal fiber was cut into a length of 70 mm, and collected in a filter shape so as to have a porosity of 85% to produce a high-temperature heat-resistant metal porous body.

This high-temperature heat-resistant metal porous body was 25 mm wide,
After being formed into a shape having a length of 800 mm, after sintering at 1100 ° C. for 2 hours under an inert gas atmosphere, electrodes made of stainless steel were attached to both ends, and then at 1000 ° C.
Heat treatment was performed for 6 hours to precipitate alumina on the surface, thereby obtaining a self-heating type high-temperature heat-resistant metal porous filter. Four processing units (processing units 3 to 6 in FIG. 1) each including one self-heating type high-temperature heat-resistant metal porous filter disposed in a container are installed so that the relationship with respect to the exhaust gas flow is parallel. A particulate collection device was formed.

The particulate trapping device was interposed in the middle of an exhaust pipe constituting an exhaust passage of a diesel engine. The diesel engine was operated at a constant load of 70%, and the exhaust gas having a black smoke concentration of 8% was passed through the particulate trap with a Bosch smoke meter.

When the differential pressure between the exhaust gas introduction part and the exhaust part of the particulate trap becomes 200 mmH ₂ O,
An electric power of 1000 W was applied to the self-heating type high-temperature heat-resistant metal porous filter a of the processing unit 3 for 2 minutes using an energizing device. After the energization is completed, when the pressure difference between the exhaust gas introduction part and the exhaust part of the collecting device becomes 200 mmH ₂ O, the energization regeneration of the next filter b is started, and the regeneration is performed in the same manner as the previous filter a. went. This operation is performed for all filters a to d.
It was repeated in the order of.

At this time, the changes over time in the differential pressure between the exhaust gas inlet and the outlet of the particulate trapping device, the surface temperature of the filters a to d, and the amount of power supplied to the filters a to d were measured. (Processing units 3 to 6 in FIG. 8). The black smoke concentration at the exhaust gas inlet and outlet of the particulate trap was measured, and the average black smoke removal rate was calculated.
4%.

[0084]

As described above, according to the first and fifth aspects of the present invention, it is possible to improve the purifying ability and durability of exhaust gas discharged from a diesel engine or the like.
In addition, it is possible to improve the economy and the maintainability. In particular, since the filter is controlled so as to be sequentially energized at the time of regeneration, a large amount of electric power is not required for the energized regeneration, which is more economical. There is an advantage.

According to the second aspect of the present invention, the start of energization regeneration of the filter is determined by detecting the pressure difference between the exhaust gas introduction part and the exhaust part, or by measuring the elapsed time from the start of collection. Detection or detection by detecting both the differential pressure between the exhaust gas inlet and the outlet and the time elapsed since the start of the collection enables more accurate timing of the start of power supply regeneration of the filter. And the reproducibility of the filter can be improved.

According to the third aspect of the present invention, the end of energization regeneration of the filter is determined by detecting the filter surface temperature, the exhaust gas temperature of the exhaust gas introduction section or the exhaust gas temperature of the exhaust section, or performing regeneration. By detecting the elapsed time from the start, or by detecting both the filter surface temperature and the elapsed time from the start of the regeneration, the end time of the power supply regeneration of the filter can be more clearly determined. The determination can be made accurately, and the reproducibility of the filter can be improved.

According to the fourth aspect of the present invention, it is possible to reliably control the amount of current supplied to the filter.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of an exhaust gas purification device according to the present invention.

FIGS. 2A and 2B are diagrams showing a configuration of a processing unit, wherein FIG. 2A is a plan sectional view, and FIG.

FIG. 3 is a time chart showing experimental data of Example 1 of the present invention.

FIG. 4 is a time chart showing experimental data of Example 2 of the present invention.

FIG. 5 is a time chart showing experimental data of Example 3 of the present invention.

FIG. 6 is a time chart showing experimental data of Example 4 of the present invention.

FIG. 7 is a time chart showing experimental data of Example 5 of the present invention.

FIG. 8 is a time chart showing experimental data of Example 6 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diesel engine 2 Exhaust pipe 2A Exhaust gas introduction part 2B Exhaust part 3-6 Processing unit 7 Differential pressure gauge 8-11 Temperature sensor 12 Electrode 13 Power supply 14 Relay 15 Controller 16 Filter 17 Packing 18 Electrode 19 Container a-d Filter

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F01N 3/02 341 F01N 3/02 341M B01D 39/20 ZAB B01D 39/20 ZABA 46/42 46/42 B 53/94 53 / 36 103C B22F 3/10 ZAB B22F 3/10 ZABZ (72) Inventor Katsumi Shinto 44 (72) Inventor Shinsuke Iijima Shinsuke Iijima 13-13 Kanahiracho, Gamagori-shi, Aichi Prefecture (72) Inventor Tatsuhiko Kato 5-6-5 Midorigaoka, Shinshiro City, Aichi Prefecture (72) Inventor Koichi Goi 3-23-26, Uechi, Okazaki City, Aichi Prefecture (72) Yukio Aizawa 203, Kizuki Omachi, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inventor Yasuo Sekido 6-28-7 Yokodai, Isogo-ku, Yokohama-shi, Kanagawa Prefecture (72) Inventor Haruo Komaki 2-5-1-131, Kikuna, Kohoku-ku, Yokohama, Kanagawa Prefecture (72) Inventor Tomonari Komiyama, Kanagawa Prefecture 3-32-1, Sakaemachi-dori, Tsurumi-ku, Yokohama-shi

Claims (5)

[Claims] 1. A self-heating high-temperature heat-resistant metal porous filter in which an electrode is attached to a free end in the middle of an exhaust gas passage having an exhaust gas introduction portion and an exhaust portion, and generates heat by flowing electricity. A current collecting device that interposes a particulate collection device including at least one or two or more processing units in parallel, and supplies electricity to the filter to regenerate the filter; and Differential pressure detecting means for detecting the differential pressure between the exhaust gas introduction section and the exhaust section,
Temperature detection means for detecting the surface temperature of the filter, the exhaust gas temperature of the exhaust gas introduction section, or the exhaust gas temperature of the exhaust section, and collection time measurement for measuring the elapsed time from the start of collection by the collection apparatus. Means for controlling the energizing device based on at least one of the means and means for measuring the elapsed time from the start of the reproduction and at least one of the means for measuring the elapsed time since the start of the reproduction; And an energization control means for controlling the energization device such that the filter is energized sequentially during regeneration. 2. The start of energization regeneration of the filter is started by the time measuring means when the differential pressure between the exhaust gas introduction part and the exhaust part becomes a predetermined value or more by the differential pressure detecting means. When the elapsed time after the predetermined time has elapsed, when the differential pressure between the exhaust gas introduction unit and the exhaust unit is equal to or more than a predetermined value by the differential pressure detection unit, or when the collection time is measured by the collection time measurement unit. 2. The exhaust gas purifying apparatus according to claim 1, wherein the detection is performed by any one of a time when an elapsed time from the start of the process has reached a predetermined time. 3. The end of energization regeneration of the filter is started by the regeneration time measuring means when the temperature of the filter surface or the exhaust gas temperature at the exhaust gas discharge section becomes higher than a predetermined value by the temperature detecting means. When the elapsed time after the predetermined time has elapsed, when the filter surface temperature or the exhaust gas temperature at the exhaust gas discharge section has become equal to or higher than a predetermined value by the temperature detecting means, or the regeneration is started by the regeneration time measuring means. The exhaust gas purifying apparatus according to claim 1, wherein the detection is performed by any one of a time when an elapsed time after the predetermined time is reached. 4. The power supply control means has a function of controlling the power supply to the filter to be constant, or a variable power supply based on the surface temperature of the filter, the exhaust gas temperature of the exhaust gas introduction section or the exhaust gas temperature of the exhaust section. The exhaust gas purifying apparatus according to any one of claims 1 to 3, further comprising a control function. 5. The self-heating high-temperature heat-resistant metal porous filter is a catalyst-carrying self-heating high-temperature heat-resistant metal porous filter carrying a catalyst.
The exhaust gas purifying apparatus according to any one of the above-mentioned items.