JPH10274030A - 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. A plurality of parallel passages (2a, 2b) are provided in the middle of an exhaust pipe (2), and each of the passages has a resistance heating property and a high-temperature heat resistance with an electrode (12) attached thereto. An energizing device that interposes a particulate collection device including a plurality of processing units A and B each including at least one heat-generating high-temperature heat-resistant metal porous filter a and b and that supplies electricity for regeneration of the filter; A power supply control means for sequentially supplying power to each processing unit at the time of regeneration, flow control valves 16A and 16B interposed in the respective passages to control the exhaust flow rate of the respective passages, and the same at the time of filter regeneration. And a flow control means for controlling the flow control valve to the flow restriction side.

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.

[0003] As a countermeasure, in a transport machine such as an automobile, the engine and the fuel injection system are improved, and thereby the particulates discharged from the diesel internal combustion engine 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, an apparatus incorporating a ceramic filter is divided into a plurality of parts, and when the amount of trapped particulates exceeds a certain amount, exhaust is performed using a valve or the like. In the method of regenerating the ceramic filter after reducing the gas flow rate, a large amount of particulates necessary for combustion propagation by the combustion heat of the particulates themselves are collected, so that the accumulated particulates are heated to a high temperature when burning. Therefore, there is a problem that the filter is melted.

In order to prevent such a filter from being damaged, when a ceramic filter is used, complicated and precise control must be performed on a valve driving device and a device for supplying secondary air to be used as necessary. There is a problem that must be. Further, 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 a self-heating type filter or a catalyst body without using a valve or the like and reducing the flow rate of exhaust gas. Also, dust collectors such as cyclones and bag filters used in stationary and industrial diesel engines have low processing capacity, are expensive, and can be installed only in places with low temperatures. There is. Further, there is a problem that the collected carbon-based fine particles (particulates) must be disposed of.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide an exhaust gas discharged from a diesel engine or the like with a high purifying ability and excellent durability. Another object of the present invention is to provide an exhaust gas purifying apparatus which is excellent in economy and maintainability.

[0009]

According to a first aspect of the present invention, there is provided an exhaust gas passage having an exhaust gas introduction portion and an exhaust portion. In each of the passage portions, a configuration in which an electrode is attached to a free end, has a resistance heating property and a high temperature heat resistance, at least a self-heating type high temperature heat resistant metal porous filter that generates heat by passing electricity, Each of a particulate collection device including one processing unit is interposed, and an energizing device that supplies electricity to the filter in order to regenerate the filter, and an energization of the filter of the processing unit during regeneration is performed by each process. Energization control means for controlling the energization device so as to be sequentially performed on the units, a flow control valve interposed in each of the passage portions to control an exhaust flow rate in each of the passage portions, Sometimes a flow control means for controlling the flow volume control valve to the flow restriction side, that it is configured to include a said.

According to a second aspect of the present invention, as the means for detecting the power supply regeneration time of the filter, a differential pressure detecting means for detecting a differential pressure between the exhaust gas introduction portion and the exhaust portion, a surface temperature of the filter or an exhaust gas. Temperature detection means for detecting the exhaust gas temperature at the introduction section or the exhaust gas temperature at the discharge section,
The apparatus includes at least one of a collection time measuring unit that measures an elapsed time since the start of collection by the collection device and a reproduction time measurement unit that measures an elapsed time since the start of reproduction. The energization control means controls the energization device based on a signal output from at least one of the means, and controls the flow rate of exhaust gas flowing into each processing unit by a flow control valve while reproducing. The present invention is characterized in that the energizing device is controlled so that the plurality of filters are energized sequentially.

According to a third aspect of the present invention, the start of energization regeneration of the filter is performed 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 fourth aspect of the present invention, the end of energization regeneration of the filter is performed when the surface temperature of the filter 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 from the start of the regeneration by the measuring means has reached a predetermined time, when the filter surface temperature has become equal to or higher than a predetermined value by the temperature detecting means, or after the regeneration is started by the regeneration time measuring means Is detected when the elapsed time reaches a predetermined time.

According to a fifth aspect of the present invention, the power supply control means has a function of controlling the amount of power supply to the filter to be constant, a surface temperature of the filter, an exhaust gas temperature of an exhaust gas introduction section, an exhaust gas temperature of an exhaust section, It is characterized by having a function of variably controlling the amount of energization based on the exhaust gas temperature in the discharge section.

The invention according to claim 6 is characterized in that the self-heating type high-temperature heat-resistant metal porous filter is a catalyst-carrying self-heating type high-temperature-resistant metal porous filter carrying a catalyst. The operation of the present invention will be described. An electrode is attached to the free end in the middle of an exhaust gas passage having an exhaust gas introduction part and an exhaust part. The electrode has a resistance heating property and a high temperature heat resistance. A heat resistant metal porous filter or a catalyst-carrying self-heating type high temperature heat resistant metal porous filter,
An exhaust gas purification device is obtained by interposing a particulate collection device including at least one of two or more processing units arranged 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 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.

The shape of the self-heating type high-temperature heat-resistant metal porous filter or the catalyst-carrying self-heating high-temperature-resistant metal porous filter 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 across the device increases. At this time, in one of the plurality of processing units, 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 directly applied to the filter itself from the electrode at the free end. Electricity is applied to burn and remove the collected particulates. At this time, when a plurality of self-heating type high-temperature heat-resistant metal porous filters or catalyst-carrying self-heating type high-temperature-resistant metal porous filters are provided, two or more of these can be simultaneously energized.

When the regeneration of the filter in one processing unit is completed, the filters of the other processing units are energized, and this is sequentially performed to regenerate the filters of a plurality of processing units. Further, at the time of filter regeneration of each processing unit, the flow control valve in the passage section in which the processing unit provided with the filter to be regenerated is interposed is controlled to the flow restriction side.

In this case, if the flow rate limit width is too small, the temperature of the filter becomes higher than the set temperature due to the heat of combustion of the particulates.
Heat is taken away by the exhaust gas, and energy loss increases. For this reason, the flow rate limiting width for controlling the flow rate control valve to the flow rate limiting side is optimally set.

Thus, the flow rate of the exhaust gas passing through the processing unit provided with the filter to be regenerated is restricted,
The amount of electricity supplied by the electricity supply device for reproduction can be reduced. Further, since the filter or the catalyst itself is energized, the filter or the catalyst can be uniformly heated. Therefore, no unburned particulates are generated, and the durability of the filter is increased. In addition, when a catalyst is supported, the temperature at which the catalyst can be burned and removed can be reduced, so that the amount of power supplied to the filter can be further reduced.

Further, the filter can be designed so that the filter pore size and the 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 time when the energization regeneration of the filter is started is determined 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.

Further, when the filter surface temperature becomes equal to or higher than a predetermined value by the temperature detecting means, the elapsed time from the start of the regeneration by the regeneration time measuring means is equal to a predetermined time. When the filter surface temperature becomes equal to or higher than a predetermined value by the temperature detecting means, or when the elapsed time from the start of the regeneration by the regeneration time measuring means reaches a predetermined time. Is detected.

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 a single self-heating type high-temperature heat-resistant metal porous filter. 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 current 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 and outlet, and the like. May be 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 the particulates, regeneration can be started without being affected by the amount of collected particulates. Even if the filter is regenerated, the regeneration can be completed without the filter being overheated and being melted.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described in more detail. The lower limit of the average pore diameter of the porous metal body of the present invention is 1
It is 0 μm, preferably 20 μm, while its upper limit is 500 μm, preferably 200 μm. In the present invention, when 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 exhaust gas purifying catalyst of the present invention, an electrode is attached to a free end of the porous metal in order to supply power to the porous metal. 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 metal porous body of the present invention, in order to further impart heat resistance and corrosion resistance, the surface thereof is Cr oxide, Al oxide,
It is preferable to coat with one or more oxides of 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 above-mentioned porous metal body contains one or more metals selected from Cr, Al, Si and Ti. In the case where the metal porous body is subjected to an oxidation heat treatment at 500 to 1200 ° C., preferably 600 to 1100 ° C. in an oxidizing atmosphere such as air,
An oxide film of those metals 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 the electrode to the free end of the porous metal is performed before the coating step. 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 thereof 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 thereof, 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 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 self-heating type exhaust gas purifying catalyst of the present invention can be obtained by supporting a catalyst on the above-described porous metal body.

The 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.

The catalyst carrier is not particularly limited, but may be alumina, silica, zirconia, titania, ZSM
-5, at least one selected from zeolites such as USY, SAPO and Y-type zeolites, silica-alumina, alumina-zirconia, alumina-titania, silica-titania, silica-zirconia, and titania-zirconia are 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 carried on the catalyst carrier is arbitrary, but is 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 oxides 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 thereof such as an oxide, a carbonate, a nitrate, or a 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 of 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 self-heating type exhaust gas purifying catalyst of the present invention can be obtained.

Here, a plurality of parallel passages are provided in the middle of an exhaust gas passage having an exhaust gas introduction portion and a discharge portion, and an electrode is attached to a free end of each passage portion. A self-heating type high-temperature heat-resistant metal porous filter having resistance heat generation property and high-temperature heat resistance and generating heat by passing electricity is interposed with a particulate collection device comprising at least one processing unit. , To obtain an exhaust gas purification device.

The control unit controls the current supply device to supply electricity to the filter so as to regenerate the filter, and controls the current supply device so that the filter of the processing unit is sequentially supplied to each processing unit during regeneration. Energization control means, and a flow control valve interposed in each of the passages to control the exhaust flow rate of each passage, and a flow control means to control the flow control valve to the flow restriction side during filter regeneration, It is comprised including.

When the self-heating type high temperature heat-resistant metal porous filter or the catalyst-carrying self-heating type high temperature heat-resistant porous metal catalyst 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, an energizing device, and the processing unit.
It comprises various sensors as various detecting means, a flow control valve, an energization control means, a flow control 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, the self-heating type high-temperature heat-resistant metal porous filter or the catalyst-carrying self-heating type high temperature The particulates are collected by the heat-resistant metal porous filter, and the differential pressure across the device increases. At this time, the filter itself is directly connected to the electrode at the free end 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 in one of the processing units arranged in parallel. The collected particulates are burned and removed by passing electricity through the device. At this time, if each processing unit is provided with a plurality of filters,
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.

After the regeneration of the filters in one processing unit is completed, the filters of the other processing units are energized, and this is sequentially performed to reproduce the filters of the plurality of processing units. Further, at the time of filter regeneration of each processing unit, the flow control valve in the passage section in which the processing unit provided with the filter to be regenerated is interposed is controlled to the flow restriction side.

As a result, the flow rate of exhaust gas passing through the processing unit provided with the filter to be regenerated is restricted,
The amount of electricity supplied by the electricity supply device for reproduction can be reduced. In addition, a plurality of filters provided in each processing unit are one.
It is energized one by one in order. As a result, the collected particulates can be processed without applying a large amount of electric power to energize the entire filter.

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 pore size and porosity of the self-heating type high temperature heat-resistant metal porous filter 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 an exhaust gas introduction part and an exhaust part, a temperature detection means for detecting a surface temperature of the filter, a particulate collection At least one of a collection time measuring means for measuring an elapsed time from the start of collection by the device and a reproduction time measuring means for measuring an elapsed time from the start of reproduction. A controller configured to control the energizing device based on a signal output from at least one of the respective devices, and to control the energizing device such that the plurality of filters are sequentially energized during reproduction. Has become.

Even if the current supply device is a device for fixing the amount of current supply, PI control or PID control using the surface temperature of the filter, the exhaust gas temperature at the exhaust gas inlet or outlet, etc.
It may be a device that controls the amount of electric power supplied by control or the like. 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 configuration 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 has become equal to or higher than a predetermined value by the temperature detecting means, the time elapsed from the start of the regeneration by the regeneration time measuring means is equal to a predetermined time. When the filter surface temperature becomes equal to or higher than a predetermined value by the temperature detecting means, or when the elapsed time from the start of the regeneration by the regeneration time measuring means reaches a predetermined time. Is detected.

The self-heating type high-temperature heat-resistant metal porous filter divided into a plurality of pieces or the catalyst-carrying self-heating type high-temperature-resistant metal porous filter can be used in a single 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 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. Therefore, the regeneration can be started without being affected by the amount of collected particulates because the filter is directly and uniformly heated to burn off the particulates.

FIG. 1 is a view showing one 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, 2
a and 2b are a plurality of passage portions parallel to each other, and A and B are
The processing units and the processing units, 16A and 16B, which are interposed in the passages 2a, 2b so as to be in a parallel relationship with each other, are interposed on the entrance side or the exit side of the processing units A and B in the passages 2a, 2b. Flow control valve,
7 is a differential pressure gauge for detecting a differential pressure between the exhaust gas introduction section 2A and the exhaust section 2B of the exhaust pipe 2, and 8 and 9 are processing units A
And B, temperature sensors for detecting the surface temperatures of the filters a and b, 12 is an electrode attached to the free end of each of the filters a and b, 13 is a power supply, and 14 is a power supply 1
A relay 15 interposed between 3 and each electrode 12 is a controller.

The power supply 13 constitutes the energizing device of the present invention, the relay 14 and the controller 15 constitute the energizing control means of the present invention, and the controller 15 constitutes the flow 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.

FIG. 2 shows an example of the configuration of the processing units A and B. In this example, a plurality of filters 1a to 1f are provided in a container 19 in parallel. Reference numeral 18 denotes an electrode provided at a free end of each of the filters 1a to 1f, and reference numeral 20 denotes an exhaust gas inlet. Thus, the processing units A and B
When a plurality of filters 1a to 1f are provided in parallel to each other, in addition to the relay 14 shown in FIG.
The relay for switching the power supply to 1f is connected to each processing unit A,
B is provided for each.

Next, specific examples of the self-heating type high temperature and heat resistant metal porous filter and the catalyst-carrying self-heating type high temperature and heat resistant metal porous filter according to the present invention will be described. (Example 1) Cr: 20.02% Al: 4.9%, La: 0.08%, balance Fe
Cut high-temperature heat-resistant metal fibers with a cross section of 50 × 10μm made of high-temperature heat-resistant metal consisting of unavoidable impurities by coil material cutting method into 70 mm lengths, and collect them in a filter shape so that the porosity is 85%. Then, a high temperature heat-resistant metal porous body was produced.

This high-temperature heat-resistant metal porous body was formed into a shape having a width of 25 mm and a length of 800 mm, and then sintered at 1100 ° C. for 2 hours in an inert gas atmosphere. Attached and heat-treated at 1000 ° C. for 6 hours to precipitate alumina on the surface to obtain a self-heating type high-temperature-resistant metal porous filter. Two processing units each having one self-heating type high-temperature heat-resistant metal porous filter disposed in a container were installed so that the relationship with respect to the exhaust gas flow was in a parallel relationship, thereby forming a particulate collection device.

Each processing unit constituting the particulate collection device is interposed in the middle of two parallel exhaust pipes formed by branching the exhaust passage of the diesel engine, and each of the processing units is provided downstream of the processing unit. An exhaust flow control valve for controlling the exhaust gas flow in the passage was installed. 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.

110 minutes after the start of collection, the differential pressure between the exhaust gas introduction section and the exhaust section of the particulate collection device becomes 1000
mmH ₂ O, while restricting the flow rate of the exhaust gas flowing into the processing unit A to 1 Nm ₃ / hr by a flow control valve provided on the exhaust gas discharge side of the processing unit A.
The energization of the self-heating type high temperature and heat resistant metal porous filter a installed in the processing unit A was started using an energization device.
At that time, the self-heating type high temperature heat resistant metal porous filter a
The surface temperature was measured by a temperature sensor 8 as a temperature detecting means, the maximum temperature was set to 610 ° C., and the maximum power amount was set to 1000 W, and power was adjusted while adjusting the power amount by PI control. When the surface temperature of the filter a reaches 600 ° C,
The energization of the filter a was terminated. After 105 minutes from the start of energization of the filter a, the differential pressure between the exhaust gas introduction part and the exhaust part of the particulate trap is 1000 mmH ₂
When it reached O, the power supply to the filter b of the other processing unit B was started, and the regeneration was performed in the same manner as the previous filter a. This operation was repeated.

At this time, changes over time in the filter surface temperatures of the filters a and b, the amount of electric power supplied to the filters, and the flow rate of the exhaust gas passing through each processing unit were measured. 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 to be 75%. In FIG. 3 and FIGS. 4 to 6 described later, the diagram of A indicates the filter surface temperature, and the diagram of B indicates the supplied electric energy. (Example 2) Cr: 20.02%, Al: 4.9%, La: 0.08%, balance
A high-temperature heat-resistant metal fiber with a cross section of 50 × 10 μm made from a high-temperature heat-resistant metal consisting of Fe and unavoidable impurities by a coil material cutting method is cut to a length of 70 mm, and formed into a filter shape with a porosity of 85%. By stacking, a high temperature heat-resistant metal porous body was produced.

This high-temperature heat-resistant metal porous body was formed into a shape having a width of 25 mm and a length of 800 mm, and then sintered at 1100 ° C. for 2 hours in an inert gas atmosphere. Attached and heat-treated at 1000 ° C. for 6 hours to precipitate alumina on the surface to obtain a self-heating type high-temperature-resistant metal porous filter. 7 g of titania particles were mixed into 200 ml of an aqueous solution prepared from 3.8 g of copper nitrate trihydrate, 2.6 g of potassium nitrate, and 1.8 g of ammonium molybdate tetrahydrate, and the mixture was stirred to evaporate water.
The catalyst was prepared by drying at 130 ° C for 1 hour and calcining at 500 ° C for 2 hours. 10 g of this catalyst was mixed with 90 ml of 99% ethanol aqueous solution and pulverized and mixed in a ball mill for 24 hours to prepare a catalyst slurry. This slurry has a spout diameter
Using a 0.4 mm two-fluid spray nozzle, the air was sprayed onto a self-heating type exhaust gas purification filter at a distance of 15 cm at an air pressure of 3 kg / cm ² . Then 13 ° C
For 1 hour and calcined at 500 ° C. for 2 hours to obtain a self-heating type high temperature heat resistant metal porous filter carrying a catalyst.

Two processing units each including one self-heating type high-temperature-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. Each processing unit constituting the particulate collection device is interposed in the middle of two parallel exhaust pipes formed by branching the exhaust passage of the diesel engine, and each passage unit is provided downstream of the processing unit. An exhaust flow control valve for controlling the exhaust gas flow was installed.

Operate diesel engine at a constant 70% load
And the black smoke density is 8% with a Bosch smoke meter.
Pass the exhaust gas through this particulate trap
Was. Particulate collection 90 minutes after starting collection
The differential pressure between the exhaust gas inlet and outlet of the device is 1000mmH_TwoO
And the flow rate of the exhaust gas flowing into the processing unit A
Flow control installed on the exhaust gas discharge side of processing unit A
1 Nm depending on your valve _Three/ Hr while limiting to
Self-heating type high temperature heat resistant metal porous filter
The energization was started using an energizing device on the filter. then,
Surface temperature of self-heating type high temperature heat resistant metal porous filter a
Is measured by the temperature sensor 8 as a temperature detecting means.
Set the temperature to 560 ° C and the maximum power to 750W,
Electricity was adjusted while controlling the amount of power. fill
When the surface temperature of the filter a reaches 550 ° C, the filter
The energization to a was terminated. Start energizing filter a
85 minutes later, the exhaust gas of the particulate
Pressure difference between inlet and outlet is 1000mmH_TwoWhen you reach O
Then, energize the filter b of the other processing unit B.
Then, reproduction was performed in the same manner as in the case of the filter a. So
After that, this operation was repeated.

At this time, changes over time in the filter surface temperatures of the filters a and b, the amount of electric power supplied to the filters, and the flow rate of the exhaust gas passing through each processing unit were measured. 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 to be 82%. (Example 3) Cr: 20.02%, Al: 4.9%, La: 0.08%, balance
A high-temperature heat-resistant metal fiber with a cross section of 50 × 10 μm made from a high-temperature heat-resistant metal consisting of Fe and unavoidable impurities, cut by a coil material cutting method, is cut into 70 mm lengths and formed into a filter so that the porosity is 85%. By stacking, a high temperature heat-resistant metal porous body was produced.

This high-temperature heat-resistant metal porous body was formed into a shape having a width of 25 mm and a length of 800 mm, and then sintered at 1100 ° C. for 2 hours under an inert gas atmosphere. Attached and heat-treated at 1000 ° C. for 6 hours to precipitate alumina on the surface to obtain a self-heating type high-temperature-resistant metal porous filter. Two processing units each having one self-heating type high-temperature heat-resistant metal porous filter disposed in a container were installed so that the relationship with respect to the exhaust gas flow was in a parallel relationship, thereby forming a particulate collection device.

Each processing unit constituting the particulate trapping device is interposed in the middle of two parallel exhaust pipes formed by branching the exhaust passage of the diesel engine, and each processing unit is provided downstream of the processing unit. An exhaust flow control valve for controlling the exhaust gas flow in the passage was installed. The diesel engine was operated at a constant load of 70%, and an exhaust gas having a black smoke concentration of 8% was passed through the particulate trap with a Bosch smoke meter.

At 110 minutes after the start of collection, the flow rate of exhaust gas flowing into the processing unit A was adjusted to 1 Nm ₃ by a flow control valve installed on the exhaust gas discharge side of the processing unit A.
The electric power of 700 W was supplied to the self-heating type high temperature and heat resistant metal porous filter a installed in the processing unit A by using a power supply device while limiting to / hr. At this time, the surface temperature of the self-heating type high temperature heat-resistant metal porous filter a is measured by the temperature sensor 8 as a temperature detecting means, and when the surface temperature of the filter a reaches 600 ° C. Was turned off. After energizing filter a,
After one minute, the power supply to the filter b of the other processing unit B was started, and the regeneration was performed in the same manner as the previous filter a.
Thereafter, this operation was repeated.

At this time, changes over time in the filter surface temperatures of the filters a and b, the amount of electric power supplied to the filters a and b, and the flow rates of the exhaust gas passing through the processing units A and B were measured.
After measuring the concentration of black smoke at the exhaust gas inlet and outlet of the particulate trap, and calculating the average black smoke removal rate,
70%. (Example 4) Cr: 20.02%, Al: 4.9%, La: 0.08%, balance
A high-temperature heat-resistant metal fiber with a cross section of 50 × 10 μm made from a high-temperature heat-resistant metal consisting of Fe and unavoidable impurities, cut by a coil material cutting method, is cut into 70 mm lengths and formed into a filter so that the porosity is 85%. By stacking, a high temperature heat-resistant metal porous body was produced.

After forming this high-temperature heat-resistant metal porous body into a shape having a width of 25 mm and a length of 800 mm, sintering was performed at 1100 ° C. for 2 hours in an inert gas atmosphere. Attached and heat-treated at 1000 ° C. for 6 hours to precipitate alumina on the surface to obtain a self-heating type high-temperature-resistant metal porous filter. 200 ml of an aqueous solution prepared by preparing 7 g of titania particles from 3.8 g of copper nitrate trihydrate, 2.6 g of potassium nitrate, and 1.8 g of ammonium molybdate tetrahydrate
Water was evaporated while stirring the mixed solution, dried at 130 ° C for 1 hour, and calcined at 500 ° C for 2 hours.
A catalyst was prepared. 10 g of this catalyst was mixed with 90 ml of a 99% pure ethanol aqueous solution, and pulverized and mixed in a ball mill for 24 hours to prepare a catalyst slurry. The slurry was sprayed onto a self-heating type exhaust gas purifying filter at a distance of 15 cm at an air pressure of 3 Kg / cm ² by using a spray nozzle of a two-fluid nozzle having a nozzle diameter of 0.4 mm. Then 130
After drying at 1 ° C. for 1 hour, it was calcined at 500 ° C. for 2 hours to obtain a catalyst-supporting self-heating high-temperature-resistant metal porous filter.

Two processing units each having one self-heating type high-temperature heat-resistant metal porous filter disposed in a container are installed so that the relation to the exhaust gas flow is parallel.
A particulate collection device was formed. Each processing unit constituting the particulate collection device is interposed in the middle of two parallel exhaust pipes formed by branching the exhaust passage of the diesel engine, and each passage unit is provided downstream of the processing unit. An exhaust flow control valve for controlling the exhaust gas flow was installed.

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.
90 minutes after the start of collection, the flow rate of the exhaust gas flowing into the processing unit A is limited to 1 Nm ³ / hr by the flow control valve 16A installed on the exhaust gas discharge side of the processing unit A, while the processing unit A is stopped. 500W using a current-carrying device to the self-heating type high temperature heat resistant metal porous filter a installed in
Was turned on. 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 surface temperature of the filter a was 550.
When the temperature reached ° C, the power supply to the filter a was terminated. 90 minutes after the start of energization of the filter a, the energization of the filter b of the other processing unit B is started,
Regeneration was performed in the same manner as in the filter a. Thereafter, this operation was repeated.

At this time, the surface temperature of the filters a and b, the amount of electric power supplied to the filters a and b, and the change over time of the flow rate of the exhaust gas passing through each of the processing units A and B were measured. 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 to be 81%.

[0080]

As described above, according to the first and sixth 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 economical efficiency and maintainability. In particular, the processing unit is controlled so that power is sequentially supplied to the processing unit during regeneration, and a filter provided with a filter to be regenerated at the time of filter regeneration of each processing unit. Since the flow control valve of the passage section in which the filter is interposed is controlled to the flow restricting side, the flow rate of the exhaust gas passing through the processing unit provided with the filter to be regenerated is restricted, whereby the The amount of electricity supplied by the electricity supply device can be reduced, and there is an advantage that a large amount of electric power is not required for electricity supply regeneration, which is more economical.

According to the second and third aspects of the present invention, the start timing of the energization regeneration of the filter is determined by detecting the pressure difference between the exhaust gas introduction part and the exhaust part or starting the collection. Or by detecting both the differential pressure between the exhaust gas introduction part and the exhaust part, and the elapsed time from the start of collection, so that the regeneration of the filter can be started. The timing can be determined more accurately, and the reproducibility of the filter can be improved.

In particular, according to the second aspect of the present invention, since the filter is controlled so as to be successively energized at the time of regeneration, a large amount of power is not required for energized regeneration, which is more economical. There is an advantage. Claim 4
According to the invention, the end time of the power supply regeneration of the filter is detected by detecting the filter surface temperature, or by detecting the elapsed time from the start of the regeneration, or by starting the filter surface temperature and the regeneration. Since the recognition is made by detecting both the elapsed times from the end, the end time of the energization regeneration of the filter can be more accurately determined, and the reproducibility of the filter can be improved.

According to the fifth 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 front 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.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diesel engine 2 Exhaust pipe 2A Exhaust gas introduction part 2B Exhaust part 2a, 2b Passage part A, B Processing unit 7 Differential pressure gauge 8-11 Temperature sensor 12 Electrode 13 Power supply 14 Relay 15 Controller 16 Filter 16A, 16B Flow control valve a , B filter

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI B01D 46/42 B01D 46/42 B 53/94 53/36 103C B22F 3/10 ZAB B22F 3/10 ZABZ (72) Inventor Shinto Katsumi Toyokawa, Toyokawa City, Aichi Prefecture 44 (72) Inventor Shinsuke Iijima 13-13, Kanehira Town, Gamagori City, Aichi Prefecture (72) Inventor Tatsuhiko Kato 5-6-5 Midorigaoka, Shinshiro City, Aichi Prefecture (72) Inventor Koichi Ii 3-23-26 Uechi, Okazaki City, Aichi Prefecture (72) Inventor Yukio Aizawa 203 Kitsuki Omachi, Nakahara-ku, Kawasaki City, Kanagawa Prefecture (72) 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-shi, Kanagawa Prefecture (72) Inventor Tomonari Komiyama 3-32-1, Sakaemachi-dori, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture

Claims (6)

[Claims] An exhaust gas passage having an exhaust gas introduction portion and an exhaust portion is provided with a plurality of passage portions parallel to each other, and each of the passage portions is provided with an electrode at a free end. A self-heating type high-temperature heat-resistant metal porous filter having heat generation and high-temperature heat resistance and generating heat by passing electricity, each of which is provided with at least one processing unit provided with a particulate collection device, An energization device that supplies electricity to the filter to perform regeneration of the filter, and energization control means that controls the energization device so that energization of the filter of the processing unit during regeneration is performed sequentially for each processing unit during regeneration. A flow control valve interposed in each of the passages to control an exhaust flow rate in each of the passages; and a flow control unit that controls the flow control valve to a flow restriction side during filter regeneration. Exhaust gas purification apparatus characterized by being configured. 2. A 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 of the exhaust gas introduction section. Alternatively, a temperature detecting means for detecting an exhaust gas temperature in the discharge unit, a collecting time measuring means for measuring an elapsed time from the start of the collection by the collecting device, and a measuring means for measuring an elapsed time from the start of the regeneration. At least one of the reproduction time measuring units is provided, and the energization control unit controls the energization device based on a signal output from at least one of the units and flows into each processing unit. A configuration in which the energizing device is controlled so that the plurality of filters are sequentially energized during regeneration while controlling the exhaust gas flow rate by a flow control valve. Exhaust gas purification device according to claim 1, wherein. 3. 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 equal to or higher than a predetermined value 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. 3. The exhaust gas purifying apparatus according to claim 2, wherein the detection is performed by any one of when a predetermined time has elapsed since the start of the process. 4. The end of energization regeneration of the filter is started by the regeneration time measuring means when the surface temperature of the filter 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. When the filter surface temperature has become equal to or higher than a predetermined value by the temperature detection means, or when the regeneration time has been started by the regeneration time measurement means, for a predetermined time. The exhaust gas purifying apparatus according to claim 2 or 3, wherein the detection is made by any one of the following. 5. The power supply control means has a function of controlling the amount of power supplied to the filter to a constant value, a surface temperature of the filter, an exhaust gas temperature of an exhaust gas introduction section, an exhaust gas temperature at an exhaust section, and an exhaust gas temperature at an exhaust section. The exhaust gas purifying apparatus according to any one of claims 2 to 4, further comprising a function of variably controlling the amount of energization based on the following. 6. The self-heating type high-temperature heat-resistant metal porous filter according to claim 1, wherein the self-heating type high-temperature heat-resistant metal porous filter is a catalyst-carrying self-heating type high-temperature heat-resistant metal porous filter carrying a catalyst.
The exhaust gas purifying apparatus according to any one of claims 1 to 5.