JPH0838584A - Deodorizing apparatus - Google Patents

Abstract

PURPOSE:To prevent deodorizing characteristics after regeneration from decreasing from the original one by passing odor component-contg. air through a deodorizing body contg. at least copper oxide, a noble metal and an inorg. adsorbent and heating intermittently the deodoring body. CONSTITUTION:A nichrome wire 1 is arranged in a quartz pipe 2 covered with a catalyst film 3 and insulators 4 are mounted to constitute an deodorizing apparatus. To form this catalyst film 3, at first, chloroplatinic acid water soln. and alumina are thoroughly mixed by using a ball mill and the mixture is baked and ground to prepare a Pt-carrying alumina. Then, this alumina is mixed with a colloidal silica water soln. contg. a specified amt. of silica, water, silicalite and copper oxide in a ball mill to prepare a slurry. The outer peripheral face of the quartz pipe 2 is coated with this slurry and it is burnt to form a deodorizing body. Odor component-contg. air is made to pass through this deodorizing body to deodorize it and electricity is intermittently energized in the nichrome wire 1 to heat it intermittently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deodorizing device used for heating, hot water supply, drying, cooking, refrigerating, air conditioning equipment and the like.

[0002]

2. Description of the Related Art Heretofore, a method of arranging an adsorbent such as activated carbon or zeolite in a deodorizer to adsorb gaseous malodorous substances to deodorize has been mainly used. In addition, a device that has an ozone generation function is placed in the deodorizing device to oxidize and decompose the malodorous components with ozone gas, or an oxidative decomposition catalyst such as a noble metal is installed near the heat source such as a flame or a heating element to improve the catalyst. A method of deodorizing by heating and activating and oxidizing and decomposing odorous substances is also adopted.

Further, in recent years, a deodorizer having an inorganic adsorbent such as zeolite or sepiolite and an oxidative decomposition catalyst such as a noble metal is installed in the vicinity of a heat source such as a heating element, and when the heating element is not energized, an odorant is generated by the adsorbent. Deodorizes by adsorbing, and heats the catalyst when the heating element is energized,
A method is also used in which the odorous substance that is activated and comes into contact with the deodorant is oxidized and decomposed, and at the same time, the odorous substance that is adsorbed by the adsorbent is oxidized and decomposed to regenerate the adsorbent.

[0004]

However, such a conventional deodorizing method has the following problems.

In the method of deodorizing by adsorbing odorous substances such as activated carbon and zeolite, it is necessary to replace the adsorbent when the adsorption reaches saturation. Also, in the odor decomposition method using ozone, a special device must be provided to control the optimum ozone generation concentration for deodorization, that there are odor component species that are difficult to decompose by ozone, and the life of the ozone generator There is a problem that there is. further,
The method of deodorizing with a catalyst has a problem that it cannot be deodorized unless the catalyst is constantly heated.

Further, in the method of deodorizing with a deodorant having an inorganic adsorbent and an oxidative decomposition catalyst, when exposed at high temperature during regeneration, the noble metal which is an oxidative decomposition catalyst deteriorates, and the deodorizing property after regeneration is initially It had a problem of lowering.

An object of the present invention is to provide a deodorizing device that solves the problems of the conventional deodorizing device.

[0008]

DISCLOSURE OF THE INVENTION The present invention is a deodorizing apparatus for passing air containing an odorous component through a deodorant body containing copper oxide, a noble metal and an inorganic adsorbent and heating the deodorant body intermittently.

[0009]

When the deodorizer is not heated, the mercaptan odor such as methyl mercaptan is oxidized by the noble metal or copper oxide and converted into a disulfide to be deodorized. The product disulfide is also one of the odor components, but S
By adding high silica zeolite having a high molar ratio of iO ₂ / Al ₂ O ₃ as an adsorbent to the deodorant, disulfide can be adsorbed and the generation of offensive odor can be suppressed. This is because the high silica zeolite having a large SiO ₂ / Al ₂ O ₃ ratio has excellent disulfide adsorption properties.

[0010] In addition, the _{zeolite, W m Z n O 2n ·} sH 2
It is a hydrous silicate represented by O, W is an exchangeable metal cation, and Z is Si and Al.

Aldehyde odors and amine odors can be deodorized by being adsorbed by an inorganic adsorbent such as zeolite or sepiolite, and fatty acid odors such as acetic acid have a large specific surface area such as γ-alumina. By using the alumina contained therein as an adsorbent, it is possible to effectively deodorize.

Usually, deodorization is performed by the above method, and when the adsorption capacity of the adsorbent reaches saturation, the deodorant is heated to activate the noble metal that is the catalyst substance, and the odorous substance in contact with the deodorant. Deodorizes the odorous substances adsorbed on the adsorbent, and regenerates the adsorbing ability of the adsorbent. In this way, the deodorizing ability can be maintained for a long time, but when the deodorizing substance is exposed to a high temperature of 700 ° C in this regeneration, if either the copper oxide or the noble metal is lacking, the mercaptan deodorizing ability at room temperature Is much lower than before heating. By adding both the copper oxide and the noble metal to the deodorant, the mercaptan deodorizing ability can maintain the initial state even after the deodorant is exposed to high temperature.

The content of copper oxide of the present invention is 1 in the deodorant.
It is desirable that the content is ˜50 wt%. Copper oxide content is 1
If the amount is less than wt% or more than 50 wt%, the heat resistance of the deodorant body is deteriorated.

By the way, when the deodorizing body of the present invention is placed near the defrosting heater in the refrigerator, since the heat exchanger exists above the heater, the defrost water adhering to the heat exchanger as frost is removed. It may melt due to frost and get on the deodorant body. Depending on how the refrigerator is used, these defrost waters are generally acidic and may have a pH of around 4. Zeolite is excellent in acid resistance as SiO ₂ / Al ₂ O ₃ ratio is large, the SiO ₂ / Al ₂ O ₃ ratio is used when pH4 approximately acid less zeolite than 8 zeolite structure is destroyed, the deodorizing characteristic deterioration There is a problem such as doing. In such a case, acid resistance can be improved by using zeolite having a large SiO ₂ / Al ₂ O ₃ ratio, and a wide range of applications can be expected.

Further, by applying the deodorant to the base material of the heating element and using it as a coating layer, the heat of the heating element can be efficiently transmitted to the deodorizing element, and the oxidation decomposition ability of the noble metal can be sufficiently exhibited. Further, a ceramic body, a metal body, a holo base material, or a glass body can be used as the base material of the heating element, and quartz or glass is optimal in terms of the adhesiveness of the coating layer. In this case, it is essential to add an inorganic binder in order to improve the adhesion, and silica is the most excellent binder. By using silica, it is possible to form a coating that is difficult to peel from the base material without deteriorating the catalytic properties. The content of silica is 10-4 in the coating layer.
It is preferably 0 wt%. Silica content is 40
When the content is more than wt%, the coating film is likely to be cracked and the adhesiveness is likely to be deteriorated. On the other hand, if it is less than 10 wt%, a sufficient effect of improving adhesion of silica cannot be obtained.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

The copper oxide used in the present invention is copper (I) oxide or copper (II) oxide.

The noble metal of the present invention includes Pt or Pd.
Is preferable, and more preferable when both Pt and Pd are used. This is because the oxidative decomposition power of Pt and Pd is higher than that of Rh and Ir, and the higher activity is obtained by using both Pt and Pd. When Ru is used, Ru is volatilized and becomes a harmful substance when used at high temperature. Furthermore, by supporting a noble metal on a high specific surface area inorganic oxide such as γ-alumina, the deodorizing property can be improved.

It is desirable to include cerium oxide in the deodorant body of the present invention. By including cerium oxide in the deodorant body, the oxidative decomposition activity can be improved when the deodorant body is heated.

A typical embodiment of the deodorizing apparatus of the present invention is shown in FIG. In FIG. 1, 1 is a nichrome wire, 2 is a quartz tube, 3 is a catalyst coating, and 4 is an insulator.

A more specific embodiment will be shown below.

<Example 1> In order to investigate the relationship between the deodorant constituents and heat resistance, the following studies were conducted.

Aqueous chloroplatinic acid solution and alumina were thoroughly mixed using a ball mill, and then calcined at 500 ° C. and pulverized to prepare Pt-supported alumina. 160 g of this Pt-supported alumina, 400 g of an aqueous colloidal silica solution containing 20 wt% of silica, 200 g of water, 160 g of silicalite, which is one of the high silica zeolite, and 12 g of copper (II) oxide, are thoroughly mixed using a ball mill. Then, a slurry A was prepared.

On the other hand, outer diameter 10 mm, inner diameter 9 mm, length 3
The outer peripheral surface of the 44 mm quartz tube 2 was degreased and washed.

After coating the slurry A on the outer peripheral surface of the central portion of the quartz tube 2 excluding 33 mm on both sides by a spray method, 100 ° C.
Then, the quartz tube 2 having the catalyst coating 3 was prepared by drying for 2 hours and baking at 500 ° C. for 1 hour. The coating weight is 1.0 g and the Pt content is 25 mg.

A 40 Ω coil-shaped nichrome wire 1 was built in this quartz tube 2, and both sides of the quartz tube 2 were insulated and held by an insulator 4 to produce a heating element A.

Further, in the slurry A, a slurry B containing no copper oxide was prepared, and a heating element B was similarly prepared.

Further, in the slurry A, a slurry C was prepared by using alumina containing no Pt to prepare a heating element C containing no Pt.

A methyl mercaptan purification test was conducted on the heating elements A, B and C. The methyl mercaptan purification test was performed by placing a heating element in a 250 l cubic container made of fluorine resin, injecting methyl mercaptan into the container so that the concentration became 8 ppm, and examining the methyl mercaptan concentration after 90 minutes. . The heating element was not heated and the measurement was carried out by gas chromatography. Further, after the adsorption test, the nichrome wire 1 and the insulator 4 of the heating element are removed, the heating element is heated in air at 700 ° C. for 20 hours, cooled to room temperature, and again subjected to a methyl mercaptan purification test to check the heat resistance of the deodorant element. It was The results are shown in (Table 1).

[0030]

[Table 1]

As is clear from (Table 1), the heating element to which only the noble metal or only copper oxide is added is 700 ° C.
However, the heat resistance of the deodorant can be improved by adding both copper oxide and a noble metal. <Example 2> The following studies were conducted in order to examine the amount of copper oxide added and the heat resistance of the deodorant.

Aqueous chloroplatinic acid solution and alumina were thoroughly mixed using a ball mill, followed by firing at 500 ° C. and pulverization to prepare Pt-supported alumina. 217.2 g of this Pt-supported alumina, 300 g of an aqueous colloidal silica solution containing 20 wt% of silica, 200 g of water, 120 g of silicalite and 2.8 g of copper (II) oxide were thoroughly mixed using a ball mill to form a slurry. D was prepared.

On the other hand, like the heating element A, the heating element D was prepared using the slurry D. The coating weight is 1.0 g and the Pt content is 25 mg.

Furthermore, the amount of copper oxide added is variously changed,
A heating element was produced by supplementing the increase / decrease in the amount of copper oxide with Pt-supported alumina. The coating weight was kept constant, and the amount of Pt supported on the Pt-supported alumina was adjusted so that the Pt content was also constant.

Next, in the same manner as in Example 1, the methyl mercaptan deodorizing characteristics of the heating element before and after the heat resistance test at 700 ° C. for 20 hours were examined. The results are shown in (Table 2).

[0036]

[Table 2]

As shown in (Table 2), the addition amount of copper oxide was 1
When it was lower than wt% or higher than 50 wt%, the heat resistance was significantly lowered. As a result, it is considered that the optimum copper oxide content is 1 to 50 wt%. <Example 3> The following studies were conducted to investigate the acid resistance of zeolite.

Instead of silicalite in Slurry A, the SiO ₂ / Al ₂ O ₃ ratio was _2, 5.5, 7.
5,8,11 Na ion exchange A type zeolite, HY
Type zeolite, erionite, offretite, and H-mordenite were used to prepare a slurry, which was coated on a quartz tube to produce heating elements E, F, G, H, and I.

This heating element was immersed in an acetic acid aqueous solution having a pH of 3.5 for 1 week at room temperature and then baked to obtain the weight reduction of the coating film.
The acid resistance of zeolite was investigated. The results are shown in (Table 3). Zeolite, which has poor acid resistance, dissolves in an acidic solution to reduce the coating film, but as shown in (Table 3), SiO ₂ / Al ₂
The larger the O ₃ ratio, the better the acid resistance, especially SiO ₂ /
It can be seen that Al ₂ O ₃ = 8 or more is excellent.

[0040]

[Table 3]

Further, a heating element A using SiO2, which is a high silica zeolite, as an adsorbent, SiO ₂ / A
With respect to the heating element E using Na ion-exchanged A-type zeolite with an l ₂ O ₃ ratio = 2, the amount of dimethyl disulfide generated during deodorization of methyl mercaptan was compared.

A methyl mercaptan purification test before the heat resistance test was conducted in the same manner as in Example 1, and the methyl mercaptan concentration and the amount of dimethyl disulfide produced after 90 minutes were examined. The results are shown in (Table 4).

[0043]

[Table 4]

As is clear from (Table 4), the use of silicalite makes it possible to suppress the generation of dimethyl disulfide. This is because silicalite adsorbs dimethyl disulfide, which is a product of methyl mercaptan partially oxidized on Pt or copper oxide, and is due to the remarkably large SiO ₂ / Al ₂ O ₃ ratio of silicalite. It is thought that. <Example 4> In order to select a base material for forming a deodorant as a coating film, a film is formed using various base materials,
The adhesion was examined.

Quartz plate, aluminum plate, stainless steel plate (SUS430) having a width of 100 mm × 90 mm and a thickness of 1 mm
Was degreased and washed. Slurry A was applied to one surface of each of these base materials and baked at 400 ° C. to form a film. The coating weight was 1.0 g.

For these, an underwater quenching test of heating at 400 ° C. and immediately dropping in water at room temperature was repeated 5 times,
The peeling of the coating was examined. The results are shown in (Table 5). (Table 5)
Good thermal shock resistance can be obtained by using a quartz substrate as shown in FIG.

[0047]

[Table 5]

Further, in slurry A, colloidal silica as an inorganic binder was removed, and a coating was formed on a quartz plate with a slurry containing no binder. In the above-mentioned rapid cooling test in water, most of the coating was obtained by rapid cooling in water once. Peeled off. As a result, it was found that the inorganic binder is indispensable for obtaining good thermal shock resistance.

[0049]

As described above, by using the deodorant product of the present invention, a deodorant product having excellent heat resistance can be obtained.

Further, it is possible to suppress the production of dimethyl disulfide, which is a by-product when purifying methyl mercaptan.

Further, by forming the deodorant body as a film on the outer surface of the quartz or glass body containing the electric resistor by using an inorganic binder, the deodorant body excellent in thermal shock resistance can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of an example of a heating element used in the present invention.

[Explanation of symbols]

 1 Nichrome wire 2 Quartz tube 3 Catalyst coating 4 Insulator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location B01D 53/86 B01J 20/06 A 20/18 E (72) Inventor Yasuhiro Fujii Osaka Prefecture Kadoma City 1006 Kadoma Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A deodorizing device for passing air containing an odor component through a deodorant body containing at least copper oxide, a noble metal and an inorganic adsorbent, and heating the deodorant body intermittently. 2. The content of copper oxide in the deodorant body is 1 to 50 w.
The deodorizing device according to claim 1, which is t%. 3. The deodorizing device according to claim 1, wherein the inorganic adsorbent is a zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 8 or more. 4. A quartz or glass body containing an electric resistor, and a deodorant body containing at least copper oxide, a noble metal and an inorganic adsorbent formed as a coating on the outer surface of the quartz or glass body with an inorganic binder. A deodorizing device, comprising: passing air containing an odor component through the deodorizing body, and heating the deodorizing body intermittently.