JP2000325788A - Catalytic material and exhaust gas cleaning device using this catalytic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the heat capacity and improve the temperature-rising property and oxidation/decomposition performance and thereby lower odor by winding an electrically insulating plain plate and a corrugated beltlike heater alternately laminated to structure a heater for supplying heat through energizing the beltlike heater and forming a catalytic layer on the surface of the heater. SOLUTION: A cylindrical heater is obtained by corrugating a beltlike heat- resistant steel and laminating each one piece of a beltlike heater 1 with an electrode terminal fitted to both ends and an insulating plain plate 2 as layers and further, winding the heater 1 and plate 2. In this case, since the corrugated beltlike heater 1 is insulated by the insulating plain plate 2, the coiled laminated layers are not shortcircuited but voltage is applied to both electrodes only in the winding direction and thus a sufficient resistance value for generating heat is secured. After that, an undercoat layer 4 is formed on the surface of the heater 1 and a catalytic layer 5 of a noble metal such as platinum or palladium is formed on the surface of the undercoat layer 4. The undercoat layer 4 is formed of a sintered oxide containing aluminum, cerium barium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating element, a catalyst body carrying a catalyst on the heating element, and an exhaust gas purifying apparatus for deodorizing by decomposing odor components contained in exhaust gas by the catalyst body.

[0002]

2. Description of the Related Art An exhaust gas purifying apparatus for oxidatively decomposing odor components in exhaust gas is disclosed in Japanese Patent Application Laid-Open No. Hei 5-301048 (metal honeycomb catalyst carrier and catalyst for purifying exhaust gas). The contents are formed of a stainless steel thin plate with corrugated irregularities and a flat stainless steel thin plate. The two types of stainless steel thin plates are formed on a metal honeycomb catalyst carrier in which electrodes are formed to enable electricity to flow. Disclosed is a metal honeycomb catalyst for exhaust gas purification in which a catalyst component is supported on a metal honeycomb catalyst carrier, both or one of which is expanded and coated with an insulating inorganic material.

[0003]

In this catalyst configuration, a corrugated stainless steel sheet and a flat stainless steel sheet coated with an insulating inorganic substance and having corrugations are formed. In this method, the conductive portion and the non-conductive portion are both formed of metal, although the insulating inorganic material is coated, but the reliability for securing the insulation between the conductive portion and the non-conductive portion is lacking. That is, if the insulating inorganic material is peeled off by a heat cycle, there is a defect such as a short circuit.
Further, when treating exhaust gas containing water vapor or the like, there has been a problem that the insulation resistance of the insulating inorganic substance is reduced and insulation between the current-carrying portion and the non-current-carrying portion cannot be ensured.

[0004]

According to the present invention, in order to solve the above-mentioned problems, an electrically insulating flat plate and a band-shaped heating element processed into a corrugated plate are laminated and wound on each other, and a current is supplied to the band-shaped heating element. Then, a catalyst layer is formed on the surface of the heat generating element configured to supply heat, and the heat generating element is energized to heat the catalyst layer, thereby decomposing the odor component of the exhaust gas.

[0005] Further, an exhaust gas purifying apparatus having the above-mentioned catalyst is provided.

Accordingly, the present invention aims to reduce odor by improving heat-up speed and oxidative decomposition performance with a small heat capacity, and to improve energy efficiency by increasing thermal efficiency and suppressing energy loss, thereby achieving safe and high energy efficiency. An exhaust gas purifying apparatus having a high performance deodorizing ability can be provided.

[0007]

According to the first aspect of the present invention, an electrically insulating flat plate and a band-shaped heating element processed into a corrugated plate are laminated on each other and wound, and heat is supplied by supplying electricity to the band-shaped heating element. The heating element is configured to perform the heating. With the above configuration, the belt-shaped heating element is insulated by the insulating flat plate, so that when it is wound, no short circuit occurs between the laminations, and voltage is applied to both electrodes only in the winding direction. It is possible to secure a resistance value sufficient to generate heat.

When the belt-shaped heating element is energized, the base material itself becomes a heating element, so that the base material can quickly reach the set temperature without loss of thermal energy as compared with indirect heating. . Further, since the ratio of the metal body is large, the thermal conductivity is extremely high as compared with ceramics and the like, and the temperature rises very quickly because the base material itself is a heating element.

According to a second aspect of the present invention, since the catalyst layer is formed on the heating element via the undercoat layer, the catalyst also quickly rises to the activation temperature, and even if odor is generated, the odor component is decomposed, that is, the odor component is decomposed. Is rapidly reduced, and the generation of intermediate products is extremely reduced. Further, in arranging the exhaust gas purifying device in the exhaust path, according to the configuration of the present invention, the catalyst device has a cylindrical shape, but has a cylindrical shape with good air permeability in the height direction, that is, the air flow direction. With respect to the above, the airflow resistance is small, and the belt-shaped heating element has a corrugated shape, so that when the exhaust gas passes, contact and diffusion with the catalyst are repeatedly performed, and the efficiency of contact with the catalyst is improved.

Further, according to the configuration of the present invention, if the cross section of the exhaust path is circular, the radial direction
The amount of leakage at the periphery of the catalyst device can also be reduced, and as a result, the input energy can be efficiently transmitted to the catalyst, and a catalyst having a high purification ability with less energy loss can be obtained.

According to a third aspect of the present invention, the heat-generating body according to the first aspect and the catalytic flat body according to the second aspect are made of inorganic fiber thin plates, thereby ensuring heat resistance, flexibility and insulation. Is easy and the workability is excellent.

According to a fourth aspect of the present invention, there is provided an exhaust gas purifying apparatus having the catalyst body according to the first aspect.

According to a fifth aspect of the present invention, as an exhaust gas purifying apparatus, a sheet made of an electrically insulating material is provided outside a heating element or a catalyst body in an exhaust path.

Since an exhaust gas purifying device requiring a high temperature is arranged, the exhaust path is generally formed as a metal casing made of stainless steel or the like. At this time, since the catalyst is directly applied to the catalyst, it is necessary to secure insulation between the catalyst and the housing.

Even when the exhaust gas discharged from the airframe contains a large amount of water, if the power is turned on and a voltage is applied to the catalyst, the catalyst temperature rises to the activation temperature and the ambient temperature also rises. In the steady state, since moisture exists as water vapor, conduction does not occur between the catalyst body and the housing because the electric insulating sheet is interposed therebetween.

However, if sufficient time has not elapsed after the temperature has been lowered after the processing has been completed, water vapor condenses inside the exhaust path, exists as liquid water droplets, and adheres to the wall surface. At this time, even if the sheet itself is an electrically insulating material, if it is in a porous or fibrous state, if it has a hygroscopic property, moisture will act as a carrier and conduction will occur, resulting in insulation between the base material and the housing. Performance decreases. At this time, if the power is turned on again, in the worst case, a short circuit occurs between the catalyst and the housing, which may result in a very dangerous state.

Therefore, if a sheet having very low hygroscopicity and low moisture absorption, preferably a sheet that does not absorb moisture at all, is used as the electrical insulating material between the base material and the exhaust path as in the present invention, even if the sheet contains moisture, Insulation can be ensured and safety is improved.

According to a sixth aspect of the present invention, a heating means for heating the moisture-resistant sheet is provided outside the exhaust path.

This is because if the water vapor is condensed and the sheet absorbs moisture as described above, the insulation performance is reduced. Therefore, before turning on the power to the catalyst substrate, the heating means is operated to heat the sheet. If the moisture absorbed by the sheet is evaporated, the insulation performance is restored again, and a similarly safe exhaust gas purifying apparatus can be obtained.

At this time, as can be understood from the above description, it is necessary to have a circuit configuration in which the heating means is operated before the power supply of the catalyst is turned on, and the power supply of the catalyst is not turned on until the insulation performance is restored.

Further, the combination of the moisture-resistant sheet and the present structure further increases the safety and can be useful.

According to a seventh aspect of the present invention, in the exhaust gas purifying apparatus, a plurality of catalysts are arranged in series in the ventilation direction, and at least the catalyst at the most upstream portion of the exhaust gas is heated to heat the catalyst layer.

The temperature of the catalyst body at the uppermost stream of the exhaust gas quickly rises to the catalytic activity when the power is turned on, and the temperature of the downstream unit is increased by heat transfer and radiation from the upstream unit without turning on the power. . Further, the temperature of the catalyst body in the downstream portion rises quickly because the base material is made of expanded metal or the like having a small heat capacity. Hereinafter, the same applies to the units on the further downstream side.

[0024] Thus, by adopting the above configuration, heat can be used more effectively than when a single catalyst body is used and the whole is energized. As a result, the same deodorizing performance can be obtained.
Energy can be reduced.

According to the present invention, the catalyst layer carries a noble metal catalyst containing at least one of platinum and palladium on the surface of the undercoat layer, and the undercoat layer contains a sintered oxide containing aluminum, cerium and barium. Things.

By containing aluminum and cerium in the undercoat layer, mutual adhesion with the substrate is generated by the sintered oxide aluminum oxide / cerium composite oxide, and the undercoat layer is firmly held and adhered. And a catalyst device with high durability can be obtained.

Further, by containing barium, the generation of acetic acid odor, which has been generated due to poor conversion with a conventional manganese oxide catalyst, is particularly reduced without impairing the above-mentioned adhesion, and the purification and deodorization performance is further reduced. It can be good.

The catalyst is a noble metal catalyst containing at least one of platinum and palladium. platinum,
Palladium has high activity as a noble metal catalyst, is most effective for oxidatively decomposing low-boiling molecules that are odor components, and can further reduce odor.

[0029]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 designates a band-shaped heating element made of a thin metal plate, which has been subjected to the following processing. First, Ni-Cr heat-resistant steel and Fe-Cr-Al heat-resistant steel are suitable as the material. This is Ni-Cr or Fe-Cr-
If any of Al is used, it is particularly excellent in durability and has high specific resistance, which is useful as a heating element. In this embodiment, in order to match the undercoat layer formed on the surface of the heating element and the coefficient of thermal expansion of the catalyst, the thickness is 0.1 mm and the width is 5 m.
m of Fe-Cr-Al heat-resistant steel (NTK No. 4L manufactured by Nippon Metal Industry), and the heat-resistant steel was corrugated to form a belt-shaped heating element. In this embodiment, the height is 3 mm and the pitch is 2 mm.

The processed belt-shaped heating element was further added to 950
Annealing treatment was performed in an air atmosphere at ℃. This is because a more durable catalyst substrate can be obtained by forming a dense passive film on the surface by annealing. According to the test results of the present inventors, the temperature was set to 950 ° C., at 900 ° C. or less, the amount of oxide film formed was insufficient and the durability was low. When the temperature exceeded 1000 ° C., crystal grains grew too much and became brittle. This is because the strength becomes insufficient.

In FIG. 1, reference numeral 1 denotes a strip-shaped heating element which has been subjected to the above-described processing, and electrode terminals 3 are attached to both ends thereof. Reference numeral 2 denotes a sheet-like ceramic paper having a thickness of 0.5 mm, which is used as an insulating flat plate.

The corrugated strip-shaped heating element 1 and insulating flat plate 2 are laminated one by one and wound as shown in FIG.
A cylindrical heating element having a height of 0 mm and a height of 5 mm was obtained. At this time, since the corrugated band-like heating element 1 is insulated by the insulating flat plate 2, no short circuit occurs between the laminations when it is wound,
A voltage is applied to both electrodes only in the winding direction, and a resistance value sufficient to generate heat is ensured.

Next, an undercoat layer 4 is formed on the surface of the heating element.

The undercoat slurry is prepared using a sintered oxide described below.

720 parts by weight of aluminum hydroxide, 217 parts by weight of cerium nitrate hexahydrate, 38 parts by weight of barium carbonate, and 1520 parts by weight of ion-exchanged water are stirred and mixed.
Dry at ℃. Further, after sintering at 1000 ° C. for 60 minutes, pulverization is performed. 400 parts by weight of the thus obtained sintered oxide, 50 parts by weight of aluminum nitrate nonahydrate, 80 parts by weight of colloidal alumina, and 460 parts by weight of ion-exchanged water were mixed and pulverized by a ball mill to have a viscosity of 105 cP and an average of 105 cP. The undercoat slurry was adjusted to a particle size of 4.1 μm.

After applying 5.0 g of the undercoat slurry to the substrate, the slurry was dried at 130 ° C. for 20 minutes.
By baking at 0 ° C. for 20 minutes, the undercoat layer 4 was formed.

Next, a catalyst layer is formed.

A 4.5 wt% aqueous solution of dinitrodiamine palladium nitric acid and a 4.5 wt% aqueous solution of dinitrodiamine platinum nitrate are mixed at a ratio of 1: 1 to apply 5.0 g. Thereafter, the catalyst layer 5 was formed by drying at 130 ° C. for 20 minutes and calcining at 600 ° C. for 20 minutes.

With the above adjustment, the undercoat layer 4 is formed on the surface of the heating element, and the noble metal catalyst layer 5 is formed on the surface of the undercoat layer 4. Here, the undercoat layer 4 functions as a connection between the heating element 1 and the catalyst layer 5, and firmly retains the catalyst on the heating element 1. The schematic diagram is shown in FIG. The catalyst constructed as described above was mounted on an exhaust gas purification device, and the performance was evaluated using a garbage disposer. The garbage disposer itself is a commercial product (Matsushita Electric MS-
N10) was used.

(Experimental Example 1) In order to check the basic deodorizing performance, only the exhaust path provided with the catalyst device was taken out, and the removing performance of the standard gas was examined. The standard gas is dimethyl sulfide ((CH ₃ ) ₂ S), which is an odor component generated from vegetables.
Was diluted with air to a concentration of 500 ppm.

At this time, the space velocity (SV) was set to 5000 (h- ¹ ), which is the same level as that of an actual garbage disposer, and the dimethyl sulfide concentration before and after the catalyst was examined using a gas chromatograph FID, and the removal rate was determined. The investigation was performed for each input power.

As a control experiment at this time, a ceramic honeycomb having the same volume and the same shape and carrying the same components and the same amount of catalyst was used, and a sheathed heater was mounted in front of the honeycomb. Examined. In both experiments,
The outside is wrapped with heat insulation to minimize heat dissipation to the outside.

FIG. 3 shows the results.

As shown in FIG. 3, in this embodiment, 9
Although a 9.5% removal rate was obtained, the control experiment required about 220 W to obtain the same removal rate, and the energy reduction was more than 25% as compared with the honeycomb catalyst.

This indicates that the indirect heating causes a thermal loss such as uneven temperature, whereas the direct heating reduces the loss.

Here, a catalyst body having a configuration in which a corrugated strip-shaped heating element 1 and ceramic paper 2 are wound was used.
With this configuration, there is no short circuit between the belt-like heat generating volume layers because there is an insulating flat plate therebetween, so that it is possible to secure a sufficient resistance value for heat generation, the entire belt-like heating element effectively generates heat, and Because it is a shape, it flows smoothly in the flow direction, and because it uses a belt-like heating element,
Since the heat capacity is small, the catalyst layer can be rapidly heated, and thus the exhaust gas is most efficiently purified.

Here, since the exhaust gas purifying apparatus is cylindrical, the catalyst body is also circular. However, other than circular, the catalytic converter may have an elliptical bottom surface as shown in FIG.
In the case where the above-described laminate is folded and folded as in (B), an effect similar to this can be expected.

(Example 2) An insulation test was conducted by operating the garbage disposer body using standard garbage.

Here, cabbage 150 is used as standard garbage.
g, mandarin orange 150g, rice 150g, dressing 2
A total of 700 g of 0 g and 20 g of sugar was used as a processing amount for one batch.

In the experimental method, first, the insulation resistance at 500 V between the housing of the garbage disposer completely dried and the charged portion of the catalyst substrate is measured, and then standard garbage is charged and treated. Then, a change with time of the insulation resistance of 500 V after the processing is completed is observed.

The electric insulation sheet has a water absorption of 0.1%.
Sheet material made of a 0.5 mm thick glass cloth substrate impregnated with an inorganic heat-resistant varnish (SGX-7 manufactured by Ryoden Kasei)
77) was used.

As a control experiment, a 0.5 mm thick ceramic paper having a water absorption of 10% or more was used. The results are shown in (Table 1).

[0054]

[Table 1]

From Table 1, it can be seen that the insulation performance of ceramic paper having a large moisture absorption decreases immediately after the treatment and it takes a long time to recover.
Although the insulation resistance is slightly lowered, practical safety is not a problem.

(Example 3) If ceramic paper is used for the electric insulating sheet, the insulating performance is reduced due to moisture absorption. Therefore, the power is turned on to the heating means 6 which is a ribbon heater in FIG. 5, and the moisture is regenerated from the absorbed sheet by heating.

Here, the change with time of the insulation resistance when 500 V was applied was measured. At this time, the processing residue after completion was disposed of, and heating was started after one hour had passed and the generation of water had ceased. The results are shown in (Table 2).

[0058]

[Table 2]

As described above, the insulating performance of the ceramic paper having a large moisture absorption decreases immediately after the treatment.
It is shown that if the power is supplied to the heating means 6, the reproduction is performed within 10 minutes.

Although a 200 W ribbon heater is used in this embodiment, other power and heating means may be used.

Therefore, if the heating means 6 is used, it is possible to use a sheet having moisture absorption as the insulating sheet. However, if the sheet is used in combination with a sheet having little moisture absorption, the effect is further enhanced.

At this time, it is necessary to provide a circuit configuration in which the processing power of the main body is turned on after the reproduction.

(Embodiment 4) In this embodiment, the diameter is 50 mm,
Although a catalyst body having a height of 5 mm was used, in the present experimental example, a catalyst body having a diameter of 50 mm and a height of 50 mm was prepared in the same manner.
It is assumed that the space is opened by 5 mm and stored in series in the catalyst storage section. This is shown in FIG. Reference numeral 71 denotes a catalyst body A provided on the upstream side of the exhaust gas, and 72 denotes a catalyst body B provided on the downstream side.
It is. Only the catalyst A is connected to the power supply 73. In FIG. 6, the heating means and the like are omitted.

In the same manner as in Experimental Example 1, only the exhaust path provided with the catalyst device was taken out, and standard gas (dimethyl sulfide 100
ppm). The space velocity (SV) was similarly set to 5000 (h- ¹ ), and the dimethyl sulfide concentration before and after the catalyst was examined using a gas chromatograph FID, and the removal rate was examined for each input power.

Experimental Example 1 is used as it is as a control experiment. FIG. 7 shows the results.

As shown in FIG. 7, Experimental Example 1, that is, the case where one unit of the catalytic device is used requires about 160 W to achieve a removal rate of 99.5% or more. If you turn on electricity, it will have the same removal rate,
Only about 130W is required, which results in an energy reduction of 15% or more.

This is because, when the catalyst device A in the former stage is energized, the catalyst device B on the downstream side receives heat by radiation and heat transfer by the exhaust gas flow. This shows that thermal energy efficiency is improved.

In this case, the power is supplied only to the former stage in two units. However, it is only necessary to divide the unit into a plurality of units and supply the optimum electric power to each unit according to individual conditions such as the presence or absence of SV and water vapor. is there.

(Example 5) 400 W to check the durability performance
Was continuously energized. As a control experiment, an undercoat slurry containing no sintered oxide of aluminum hydroxide, cerium nitrate, or barium carbonate was used.

In the case of the control experiment, the catalyst layer including the undercoat layer was peeled off at several places after 500 hours, while in the case of the present example, the catalyst layer showed no change even after 2000 hours. Met.

It is shown that a sintered oxide of aluminum hydroxide, cerium nitrate, and barium carbonate also has an effect on the adhesion and durability of the undercoat.

Further, an experimental example showing the effect of this embodiment will be described.

Using the garbage disposal main body, the exhaust gas when standard garbage was actually processed was evaluated. As a control experiment, one prepared using an undercoat slurry to which only barium carbonate was not added was used.

About one hour after the start of the treatment, the concentration of acetic acid in the exhaust gas was examined with a detector tube. Although not detected in this embodiment,
In the control experiment product, the color slightly changed and about 0.5 ppm was detected.

Similarly, about one hour after the start of the treatment, the exhaust gas was sampled into a 3-liter odor bag,
The name was smelled and the quality of the smell was answered.

In the control experiment product, three people answered "sour", but none in this example.

From the above, it can be seen that the addition of barium has a remarkable effect on acetic acid odor.

An experimental example showing the effect of this embodiment will be described.

Using the garbage disposal main body, the sensory evaluation of the exhaust air when the standard garbage was actually processed was performed. The power input to the deodorizer was 400 W. As a control experiment, a deodorizing device supporting only platinum, only palladium, and a manganese oxide catalyst was used.

About one hour after the start of the treatment, the exhaust gas was sampled in a 3-liter odor bag, and six panelists smelled the odor, and asked the six-step odor intensity at that time. The six-step odor intensity is as follows: 0: no odor, 1: slight smell is recognized, 2: what smell is barely recognized, 3: what smell is easily recognized, 4: strong smell, 5: strong smell
Intense odor, showing the intensity of the odor in six stages.

If the odor intensity is cut up and down and averaged,
In this example, it was 2.0, and in the control experiment, only platinum was 1.8, only palladium was 2.1, and manganese oxide was 2.9.

There is a clear difference in odor intensity of about one rank, indicating that platinum and palladium have a great effect on deodorization.

[0083]

According to the first aspect of the present invention, since the belt-shaped heating element is insulated by the insulating flat plate, a short circuit does not occur between the laminations when it is wound, and a voltage is applied to both electrodes only in the winding direction. As a result, it is possible to secure a resistance value sufficient to generate heat. When the belt-shaped heating element is energized, the base material itself becomes a heating element, so that the base material can quickly reach the set temperature without loss of thermal energy as compared with indirect heating. Further, since the ratio of the metal body is large, the thermal conductivity is extremely high as compared with ceramics and the like, and the temperature rises very quickly because the base material itself is a heating element.

According to a second aspect of the present invention, since the catalyst layer is formed on the heating element via the undercoat layer, the catalyst also quickly rises to the activation temperature, and even if odor is generated, decomposition of the odor component, that is, odor Is rapidly reduced, and the generation of intermediate products is extremely reduced. Further, in arranging the exhaust gas purifying device in the exhaust path, according to the configuration of the present invention, the catalyst device has a cylindrical shape, but has a cylindrical shape with good air permeability in the height direction, that is, the air flow direction. With respect to the above, the airflow resistance is small, and the belt-shaped heating element has a corrugated shape, so that when the exhaust gas passes, contact and diffusion with the catalyst are repeatedly performed, and the efficiency of contact with the catalyst is improved.

Further, according to the structure of the present invention, if the cross section of the exhaust path is circular, the radial
The amount of leakage at the periphery of the catalyst device can also be reduced, and as a result, the input energy can be efficiently transmitted to the catalyst, and a catalyst having a high purification ability with less energy loss can be obtained.

According to a third aspect of the present invention, the heat-generating body according to the first aspect and the catalytic body according to the second aspect are made of a thin plate of inorganic fibers, thereby ensuring heat resistance, flexibility and insulation. Is easy and the workability is excellent.

According to a fourth aspect of the present invention, there is provided an exhaust gas purifying apparatus having the catalyst body according to the first aspect of the present invention. Can be reached. Further, it is possible to provide an exhaust gas purifying apparatus in which the thermal conductivity is extremely large as compared with ceramics or the like because the ratio of the metal body is large, and the temperature rises very quickly because the base material itself becomes a heating element. it can.

According to a fifth aspect of the present invention, as an exhaust gas purifying apparatus, a sheet made of an electrically insulating material is provided outside a heating element or a catalyst body in an exhaust path.
If the sheet having extremely low hygroscopicity as described in the present invention and the sheet which does not absorb moisture at all is used as the electrical insulating material between the substrate and the exhaust path, the insulating property can be ensured even if the sheet contains moisture. , Which improves safety.

According to a sixth aspect of the present invention, a heating means for heating the moisture-resistant sheet is provided outside the exhaust path. This is because the insulation performance is reduced if the water vapor condenses and the sheet absorbs moisture as described above.Before turning on the power to the catalyst substrate, the heating means is operated to heat the sheet, so that the sheet is heated. If the moisture absorbed is evaporated, the insulation performance is restored again, and a similarly safe exhaust gas purifying apparatus can be obtained. Further, when the moisture-resistant sheet and this configuration are combined, the safety is further increased, and the sheet can be useful.

According to a seventh aspect of the present invention, in the exhaust gas purifying apparatus, a plurality of catalysts are arranged in series in the ventilation direction, and at least the catalyst at the most upstream portion of the exhaust gas is heated to heat the catalyst layer.

With this configuration, it is possible to use heat more effectively than when a single catalyst is used and the whole is energized. As a result, the same deodorizing performance can be obtained while reducing the energy. it can.

According to the present invention, the catalyst layer carries a noble metal catalyst containing at least one of platinum and palladium on the surface of the undercoat layer, and the undercoat layer contains a sintered oxide containing aluminum, cerium and barium. Things.

When aluminum and cerium are contained in the undercoat layer, mutual adhesion with the substrate occurs due to the composite oxide of aluminum oxide and cerium, which is a sintered body of the undercoat layer. And a catalyst device with high durability can be obtained.

Further, by containing barium, the generation of acetic acid odor generated due to poor conversion by the conventional manganese oxide catalyst is particularly reduced without impairing the above-mentioned adhesion, and the purification and deodorization performance is further reduced. It can be good.

The catalyst is a noble metal catalyst containing at least one of platinum and palladium. platinum,
Palladium has high activity as a noble metal catalyst, and is most effective for oxidatively decomposing low-boiling molecules, which are odor components, and can further reduce odor.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a catalyst body of the present invention.

FIG. 2 is a configuration diagram showing a part of a catalyst body of the present invention.

FIG. 3 is an experimental characteristic diagram showing the effect of the present invention.

FIG. 4 (a) is a configuration diagram showing the configuration of one embodiment of the catalyst body of the present invention, and (b) is a configuration diagram showing the configuration of another embodiment of the catalyst body of the present invention.

FIG. 5 is a sectional view showing the configuration of an embodiment of the exhaust gas purifying apparatus of the present invention.

FIG. 6 is a sectional view showing the configuration of another embodiment of the exhaust gas purifying apparatus of the present invention.

FIG. 7 is an experimental characteristic diagram showing the effect of the present invention.

FIG. 8 is a perspective view showing a configuration of a conventional catalyst body.

[Explanation of symbols]

 Reference Signs List 1 strip heating element 2 insulating flat plate 3 electrode terminal 4 undercoat layer 5 catalyst layer 6 heating means 7 insulating sheet

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Koichi Nakano 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Term (Reference) 4D048 AA22 AB03 BA03X BA03Y BA15X BA15Y BA19X BA19Y BA30X BA30Y BA31X BA31Y BB04 CC04 CC06 CC40 CC43 CC52 CC58 CC61 EA04 4G069 AA03 AA08 BC13A BC13B BC16A BC16B BC43A BC43B BC72A03 EA03EA02

Claims (8)

[Claims] An electric insulating flat plate and a band-shaped heating element processed into a corrugated plate are laminated and wound on each other, and a heat is supplied to the surface of the heating element by supplying electricity to the band-shaped heating element. A catalyst body that forms a catalyst layer and decomposes odor components in exhaust by heating the catalyst layer by energizing the heating element. 2. The catalyst layer carries a noble metal catalyst containing at least one of platinum and palladium on the surface of the undercoat layer, and the undercoat layer is a sintered oxide containing aluminum, cerium and barium. The catalyst body as described in the above. 3. An insulating flat plate comprising inorganic fibers.
Or the catalyst body according to 2. 4. An exhaust gas purifying apparatus having the catalyst body according to claim 1. 5. The exhaust gas purifying apparatus according to claim 4, wherein a moisture-resistant sheet made of an electrically insulating material is provided outside the catalyst body in the exhaust path. 6. The exhaust gas purifying apparatus according to claim 4, further comprising a heating means for heating the sheet on the outside. 7. The exhaust gas purifying apparatus according to claim 4, wherein a plurality of catalysts are arranged in series in the ventilation direction, and at least the heating element or the catalyst at the most upstream part of the exhaust is energized to heat the catalyst layer. . 8. The catalyst layer supports a noble metal catalyst containing at least one of platinum and palladium on the surface of the undercoat layer, and the undercoat layer is a sintered oxide containing aluminum, cerium and barium. An exhaust gas purifying apparatus according to any one of claims 1 to 6.