JPH0866460A - Deodorizing device - Google Patents

Abstract

PURPOSE: To make it possible to suppress heat deterioration of the oxidation medium and the absorbent in a deodorizing device by using a honeycomb made of a metal as a carrier, carrying an oxidation catalyst or an adsorption oxidation catalyst on the surface of a vent section, and contacting and holding a plate-shaped resistance exothermic inorganic material subjected to an electrode process on both sides conductively around the outer periphery of the metal carrier. CONSTITUTION: A metal deodorization honeycomb 1 is produced in such a manner that an alumite or boehmite treatment is performed to a surface of a vent section of a metal carrier 1a obtained by processing and molding a metal material such as aluminum or the like to form a square in a honeycomb state having fine vent sections and, after that, a γ-alumina layer 1b is wash coated, and further, only an oxidation catalyst 1c or an adsorption oxidation catalyst comprising an adsorbent 1d and the oxidation catalyst 1c is carried. A plate-shaped resistance exothermic inorganic material 2 is obtained in such a manner that a complex of silicon carbide and silicon nitride is molded and baked by a reaction sintering into a plate shape, a heat treatment is performed so as to obtain a predetermined resistance value, electrodes 6 are formed, and the material 2 is conductively contacted by electrode surface from both sides of the outer periphery of the metal deodorization honeycomb 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deodorizing element which is installed in a home refrigerator, an entrance storage, a toilet, or the like, or is installed in an exhaust gas passage of a cooking appliance or the like for deodorization. Is.

[0002]

2. Description of the Related Art Conventional deodorizers for household refrigerators and the like have long been made of activated carbon. This is for adsorbing odorous components in a refrigerator by diffusing or circulating air into fine pores on the surface of activated carbon formed in a granular or honeycomb shape.

Recently, there is also one using ozone. This is one in which some odors are decomposed by the oxidizing ability of ozone, the remaining odors are adsorbed by an ozone decomposing deodorizing catalyst whose main component is manganese oxide, and excess ozone is decomposed by the ozone decomposing deodorizing catalyst. Further, those using a room temperature decomposition catalyst containing an iron complex or gold as a main component are also commercially available.

In addition to the deodorization mainly due to the above-mentioned adsorption function, a deodorizing element using a heating oxidation by energizing a honeycomb-shaped resistance heating inorganic material as disclosed in JP-A-4-132662 has been proposed. ing. As shown in FIG. 5 and FIG. 6, the conductive inorganic material 10 is molded and fired into a honeycomb shape so as to have an arbitrary resistance value to form a resistance heating inorganic honeycomb 11, and the resistance heating inorganic honeycomb is formed. 1
Electrodes 12 are formed at both ends of the No. 1 and the surface of the resistance heating inorganic honeycomb 11 carries only the oxidation catalyst or the oxidation catalyst and the adsorbent.

With this, during deodorization or regeneration, the electrode 12 is energized to generate heat in the resistance heating inorganic honeycomb 11 itself, and the odor is oxidatively decomposed by the oxidation catalyst on the surface thereof.

[0006]

However, the above-mentioned deodorizer using the adsorption function has the following problems. That is, in the case of using activated carbon, the amount of adsorption gradually increases and the deodorizing effect decreases, and finally the adsorption becomes saturated and the deodorizing effect disappears, and in some cases, it becomes a source of odor generation. Even in the case of ozone, when the odor concentration is high, the odor is gradually adsorbed on the ozone decomposing deodorizing catalyst, and the deodorizing effect decreases as with activated carbon.

Also in the room temperature decomposition catalyst, the decomposition rate at room temperature is extremely slow, and most of its deodorizing effect is due to adsorption, and the deodorizing effect similarly decreases unless energy for decomposition is applied.

In any of these adsorption methods, moisture is easily absorbed, and the deodorizing performance is extremely lowered in an atmosphere of high humidity. Furthermore, when the deodorizing effect disappears, it is necessary to replace the deodorant or replace the deodorizer itself.

On the other hand, in the deodorizing element using the heating and oxidizing action by energizing the honeycomb-shaped resistance heating inorganic material, it is not necessary to replace the deodorant, and even if moisture is absorbed, the absorbed moisture is desorbed by heating, so that the desorption performance is Recover. However, depending on the cell position of the honeycomb due to temperature unevenness during firing, it will be about 50
A large temperature distribution of ˜150 ° C. is likely to occur, so that the highest temperature portion becomes unnecessarily hot in order to set the lowest temperature portion of the honeycomb as the set temperature.

The generation of the excessive maximum temperature portion causes a partial change in resistance value over time and causes thermal deterioration of the catalyst carried on the surface. Further, when deodorizing a high-humidity gas, the carrier itself easily absorbs water, so that when aluminum is used for the electrode, it easily corrodes. In addition, the complexity of the molding / firing process makes it expensive.

[0011]

The deodorizing element of the present invention has been made in view of the above-mentioned problems. The deodorizing element of the present invention is processed and molded into a honeycomb having a large contact area and used as a carrier. A plate-shaped resistance heating exothermic material having an oxidation catalyst or an adsorption oxidation catalyst supported on the surface thereof and having both surfaces subjected to electrode treatment as a heating source is held in contact with one or more outer peripheral portions of the metal carrier with good conductivity.

[0012]

The present invention has the above-described structure, and by applying a voltage between the metal carrier and the electrode surface of the plate-shaped resistance heating inorganic material which is not in contact with the metal carrier, The plate-shaped resistance heat-generating inorganic material is caused to generate heat. At this time, heat is transferred to the metal carrier having excellent thermal conductivity, which is in contact with the plate-shaped resistance heating inorganic material by heat conduction, and the metal carrier is uniformly heated.

Therefore, when the oxidation catalyst or the adsorption oxidation catalyst carried on the surface of the metal carrier reaches the activation temperature, the odorous gas passing through the aeration portion is oxidatively decomposed to be deodorized,
Further, in the case of the adsorption oxidation catalyst, the adsorbed odorous components are oxidatively decomposed to be deodorized as deodorized and regenerated.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the deodorizing element of the present invention will be described below with reference to FIGS. FIG. 1 is an enlarged perspective view of an essential portion showing an embodiment of the deodorizing element of the present invention, and FIG. 2 is an enlarged sectional view of an essential portion showing a surface state of the deodorizing element of the present invention when an oxidation catalyst is carried. FIG. 3 is an enlarged cross-sectional view of an essential part showing a surface state of the deodorizing element of the present invention when an adsorption oxidation catalyst is carried. FIG. 4 is an explanatory view of the relationship between the initial removal rate by adsorption of various cells of the deodorizing element of the present invention at room temperature and the space velocity.

Reference numeral 1 denotes a metal deodorizing honeycomb, which is made of a metal material such as aluminum or stainless steel 70 (cell / i).
n ² ) processed into a honeycomb shape with fine ventilation parts
After the surface of the aerated portion of the metal carrier 1a formed into a rectangular shape is subjected to an alumite treatment or a boehmite treatment, the γ-alumina layer 1b is wash-coated, and the oxidation catalyst 1c alone or the adsorbent 1d and the oxidation catalyst 1c are further applied. And an adsorption oxidation catalyst composed of

A platinum group metal element is used as the oxidation catalyst 1c, and one or more kinds of manganese oxide, iron oxide, titanium oxide, zeolite, silica and alumina are used as the adsorbent 1d. In No. 2, a composite of silicon carbide and silicon nitride was formed into a plate by reaction sintering and fired, then heat-treated so as to have a predetermined resistance value, and aluminum spraying or silver paste coating was applied to both surfaces to form the electrode 6. It is a plate-shaped resistance heating inorganic material. The resistance heating inorganic material 2 is a metal deodorizing honeycomb 1.
The electrode surfaces are in good contact with each other from both sides of the outer peripheral portion, and are held so as to be sandwiched by the insulator 4 having good insulating properties via the terminals 3 having a spring property for applying a voltage from both sides. Fixed inside.

In the above structure, when the oxidative deodorizing operation is performed, a metal deodorizing honeycomb carrying only an oxidation catalyst or an adsorptive oxidation catalyst is used, and a voltage is constantly applied to the terminal 3 to generate heat from the plate-shaped resistance heating inorganic material. Then, the metal deodorizing honeycomb 1 is heated to 300 ° C. or higher. At this time, the gas containing the odorous component passing through the metal deodorizing honeycomb 1 is oxidized and decomposed by the action of the oxidation catalyst 1c carried on the surface,
It becomes carbon dioxide and water and is deodorized and discharged.

When the normal temperature adsorption operation is performed, a metal deodorizing honeycomb carrying an adsorption oxidation catalyst is used and the terminal 3 is used.
A gas containing an odor component is allowed to pass through the metal deodorizing honeycomb 1 at room temperature without applying a voltage to it. At this time,
The odorous component is adsorbed by the adsorbent 1d carried on the surface of the metal deodorizing honeycomb, deodorized and discharged. While the adsorption operation continues, breakthrough occurs in the adsorbent, and the deodorizing performance gradually decreases due to the adsorption of water.

At that point, the adsorption operation is temporarily stopped,
A cleaning (regeneration) operation of heating the metal deodorizing honeycomb 1 to 300 ° C. or more by heat conduction by energizing the terminals 3 to cause the plate-shaped resistance heating inorganic material 2 to generate heat is performed. Odor components adsorbed on the adsorbent 1d by this operation are oxidatively decomposed by the oxidation catalyst 1c to become carbon dioxide gas and water, deodorized and desorbed, and the adsorbent is regenerated, so that the odor performance is restored.

Deodorizing element of this embodiment (dimensions: 40 × 40 ×
The temperature distribution (maximum temperature-minimum temperature) in the t20 mm, metal carrier: aluminum corrugated honeycomb) is 15 ° C. However, the set average temperature is 300 ° C. By the way,
The temperature distribution (maximum temperature-minimum temperature) of the conventional deodorizing element is 50 ° C to 150 ° C.

Further, in the deodorizing element of this embodiment, acetic acid for each cell number when 120 (g / l) of an adsorption oxidation catalyst using manganese oxide as a main component as an adsorbent and platinum as an oxidation catalyst was supported. The relationship between the initial removal rate by adsorption at room temperature and the space velocity is shown in FIG. In FIG. 4, the solid line a is 530 (cells / in ² ), the alternate long and short dash line b is 180 (cells / in ² ), the alternate long and two short dashes line c is 90 (cells / in ² ), and the broken line d is 70 (cells / in ² ). Is the case.

The price of the metal carrier per unit volume is low, and the cost can be significantly reduced as compared with the case of using the conventional resistance heating inorganic material carrier.

When the odorous component to be deodorized does not include a high boiling point component such as tar, the set temperature of the metal deodorizing honeycomb can be set to 280 ° C. or lower, so that the plate-shaped resistance heating inorganic material 2 Curie point (280 ° C or less)
It is also possible to use a PTC heater such as barium titanate having the above.

[0024]

Since the deodorizing element of the present invention has the above-mentioned structure, the invention according to claim 1 improves the soaking property by using the metal carrier, and therefore the oxidation catalyst and the adsorption carried on the surface of the carrier are improved. The heat deterioration of the agent is suppressed, and the heat deterioration of the resistance heating inorganic material and the change with time of the resistance value are suppressed. Furthermore, cost reduction can be achieved compared to the case of using a resistance heating exothermic inorganic material as the carrier, and since the metal carrier does not absorb water, the resistance heating property used by contacting even when deodorizing high humidity gas is used. Excellent corrosion resistance of the electrode of inorganic material plate.

In addition to the effect of the invention described in claim 1, the invention described in claim 2 uses a composite of silicon carbide and silicon nitride excellent in heat resistance as the resistance heating inorganic material plate. Since the metal carrier can be heated to 300 ° C. or higher, odors having a high boiling point component such as tobacco odor can be completely decomposed.

In addition to the effect of the invention described in claim 1, the invention described in claim 3 uses a PTC (positive temperature coefficient thermistor) heater (Curie point 2 as a resistance heating inorganic material plate.
(80 ° C. or lower), temperature control is easy and safety is high.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view of an essential part showing an embodiment of a deodorizing element of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part showing a surface state of the deodorizing element of the present invention when an oxidation catalyst is carried.

FIG. 3 is an enlarged cross-sectional view of an essential part showing a surface state of the deodorizing element of the present invention when an adsorption oxidation catalyst is carried.

FIG. 4 is an explanatory diagram of a relationship between an initial removal rate by adsorption of various cells of the deodorizing element of the present invention at room temperature and a space velocity.

FIG. 5 is a perspective view of a main part showing a structure of a conventional deodorizing element.

FIG. 6 is an enlarged view of part A of FIG.

[Explanation of symbols]

 1 Metal Deodorizing Honeycomb 1a Metal Carrier 1b γ-Alumina Layer 1c Oxidation Catalyst 1d Adsorbent 2 Resistance Heating Inorganic Material Plate 3 Terminal 4 Insulator 5 Metal Case 6 Electrode

Claims (3)

[Claims] 1. A ventilation surface of a metal carrier formed by processing and molding a metal material into a honeycomb shape having a large contact area,
An oxidation catalyst or an adsorption oxidation catalyst consisting of an oxidation catalyst and an adsorbent is supported, and one or more electrode surfaces of a resistance heat-generating inorganic material plate having electrode treatment on both sides at one or more outer peripheral portions of the metal carrier and the metal. A deodorizing element, characterized in that the outer peripheral portion of the carrier is held in good contact with the conductive material. 2. The deodorizing element according to claim 1, wherein a composite obtained by reacting and sintering silicon carbide and silicon nitride is used as the resistance heating inorganic material plate. 3. The deodorizing element according to claim 1, wherein a PTC heater such as barium titanate is used as the resistance heating inorganic material plate.