JPH02251226A - Air cleaning apparatus - Google Patents

Abstract

PURPOSE:To improve the effect of ozone to remove air polluting substances and keep the effect for a long duration by using a catalyst layer carrying catalytic components on a porous substrate where prescribed fine pores are formed in air flowing route. CONSTITUTION:A catalyst layer 3 (e.g. MnO2-TiO2) to accelerate removal of air polluting substances by ozone is formed in an air flowing route 1 where ozone and air are mixed each other. The catalyst layer 3 is comprised of a porous substrate 4 (e.g. nichrom wire mesh) where a large number of fine pores with >=30mum of diameter are formed and catalytic components carried on the substrate. As a result, effect of ozone to remove air polluting substances can be improved and the effect can be kept for a long duration and replacement and regeneration of the catalyst are not needed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an air purifier for removing indoor malodor components such as cigarette smoke, body odor, pet odor, and other air pollutants using ozone.

<Problems to be solved by conventional technology and invention> Living room,
BACKGROUND OF THE INVENTION In human living spaces such as dining rooms, conference rooms, and toilets, cigarette smoke, body odor, pet odor, and other bad odors are generated from various odor sources.

The bad odor components that humans perceive and their amounts are ammonia 1 to 10
ppm, acetaldehyde 1-10 ppm, hydrogen sulfide 0
．． 1-1 ppm %Mercaptans 0.1-lppm
In addition, nicotine, pyridine, etc. are also well known as malodorous components.

As methods for removing such air pollutants, conventional methods include adsorption removal using an adsorbent such as activated carbon, and oxidative decomposition using a photocatalytic reaction.

However, the adsorption removal method has the disadvantage that the adsorbent quickly becomes saturated with adsorption and cannot maintain a high effect over a long period of time, requiring replacement, which requires a great deal of effort and cost for maintenance. On the other hand, photocatalytic reactions oxidize and decompose air pollutants while irradiating Pt/Tl0z-based catalysts with 300-400 nm ultraviolet rays, but they cannot decompose pollutants with large molecular weights such as nicotine and tar. , these, etc. coat the surface of the catalyst and reduce its activity, so it is necessary to regenerate the catalyst each time, and it is also necessary to replace the ultraviolet lamp.

On the other hand, it has been proposed to use ozone to oxidize and decompose air pollutants. equipment is proposed. The catalyst layer used is one in which a catalytically active component is supported on an inert carrier. As the inert carrier, corrugated honeycombs made of ceramic fibers, honeycombs made of cordierite, and clay formed into various shapes such as honeycombs, pellets, cylinders, plates, pipes, etc. are used. .

However, in the case of the honeycomb type, the contact between the air and the catalyst occurs in parallel flow, and sufficient contact cannot be ensured, so there is a problem that the removal efficiency of pollutants is low. On the other hand, if the contact between the air and the catalyst is made to be in a vertical flow in order to increase the removal efficiency, there is a problem in that the pressure loss becomes large and the contaminant removal efficiency decreases as described above.

The present invention has been made in view of these problems, and has a high effect of removing air pollutants by ozone, and can maintain the removal effect for a long period of time.
The purpose is to provide an air purifier that does not require catalyst replacement or regeneration.

Means and operation for solving the problems> The air purifier of the present invention has a catalyst layer provided in the air flow path with a diameter of 30 μm.
It is characterized in that it is constructed by supporting a catalyst component on a perforated plate having a large number of pores of m or more.

In this way, the present invention uses a catalyst layer in which a catalyst component is supported on a perforated plate having predetermined pores, so that a high contact area is created between the catalyst layer and the ozone-containing air passing through the air flow path. Therefore, the oxidative decomposition reaction of air pollutants by ozone can be carried out efficiently, and a high removal effect can be obtained. At this time, the above catalyst components are not adsorbed and saturated like activated carbon, and nicotine, tar, etc. can also be decomposed by ozone, so these adhere to the catalyst surface and inhibit the catalyst activity. It's never done.

Therefore, the catalyst layer can be used for a long period of time, and there is no need for replacement or regeneration.

In the present invention, examples of the perforated plate used as a carrier include a thin wire mesh, a metal plate, etc., each having a large number of pores. The wire mesh can be made from a metal wire such as stainless steel wire or nichrome wire. Further, the pores in the metal plate can be formed, for example, by etching, punching with a mold, or lath processing.

The diameter of the pores is 30 μm or more, more preferably 200 to 50 μm.
The thickness is preferably 0 μm from the viewpoint of reactivity and pressure loss. When the diameter of the pores is smaller than 30 μm, the reactivity increases, but pressure loss also increases, which is not preferable. On the other hand, if the diameter is excessively large, there will be no pressure loss, but
Reactivity tends to decrease.

The catalyst components supported on these wire meshes and metal plates are:
For example, Mn 02-T i 02 , Mn 02SiO
z, Cu0-TiOz, CO304Ti02
, those whose main component is a binary catalyst such as Fe203-Au,
MnO2-Cos 0a-TiOz, MnO2-Co5
Examples include those whose main component is a three-way catalyst such as Oa-AgzOlNip-MnO2-Ti02.

Preferably, the amount of catalyst component supported is about 1-20%.

When the loading rate is larger than this range, there is no commensurate improvement in air purification efficiency, which is economically disadvantageous, and when the loading rate is lower than this range, sufficient air purification efficiency cannot be obtained.

The amount of ozone 03 sent to the catalyst layer for air purification such as deodorization is appropriately determined depending on the type and concentration of the air pollutant to be removed, the reaction temperature, the type and amount of the catalyst, etc. For example, if the air pollutant is H2S, HzS1
031 to 2 moles per mole, NHs 1 for NH3
Preferably, 031 to 3 mol per mole are provided respectively. Moreover, when ethyl mercaptan is contained, it is preferable to supply 0.31 to 4 moles per mole of ethyl mercaptan.

If the concentration of pollutants in the air is high, ozone may be supplied above the above range in order to improve the removal rate, but if it is too much, excess ozone may remain. It is necessary to take care to supply an appropriate amount of ozone to prevent this from happening.

The reaction temperature for air purification such as deodorization may be around normal room temperature, but in order to further increase the reaction rate, the catalyst component may be
Preferably, the temperature is lower than 0.degree.

If the temperature of the catalyst component exceeds 100°C, organic dust (lint, cotton flakes, etc.) floating in the air may ignite.
There are disadvantages such as high gas temperature after treatment. Although the heating means can be determined as appropriate, it is preferable to use a heat-generating material such as a nichrome wire as the porous plate and heat the catalyst component by passing an electric current through the porous plate because it is easy to handle.

Note that the contact between the catalyst and the reaction gas is preferably carried out at an area velocity (AV; area velocity) of 5 to 50. This is because if the areal velocity is less than 5, a large amount of catalyst is required, whereas if it exceeds 50, the efficiency is low and a predetermined decomposition rate cannot be obtained. Here, the areal velocity is the value obtained by dividing the reaction amount (Nm'/uSu:Hr) by the gas contact area per unit volume of catalyst (m2/m3).

<Example> Next, an example of an air purifier provided with the above-mentioned catalyst layer will be described based on the drawings.

FIG. 1 is a schematic sectional view showing an embodiment of the air cleaner of the present invention. This air purifier has a catalyst layer 3 and a fan 2 provided in an air flow path 1 (casing) that forms an air flow path. The catalyst layer 3 is constructed by arranging a plurality of perforated plates 4. At this time, the perforated plates 4 may be in close contact with each other or may be spaced apart from each other at appropriate intervals.

When air is drawn into the air flow path 1 from the intake port 1a,
Mixed with ozone, pollutants in the air are oxidized and decomposed in the catalyst layer 3. The purified air is then discharged into the room from the exhaust port 1b.

FIG. 2(a) and the curve are a plan view and a side view of the perforated plate 4 used in the embodiment of the present invention. That is, in this embodiment, a wire mesh made of a heat generating material is used as the perforated plate 4, and conductive holders 5.5 are attached to both ends of the wire mesh, to which lead wires 6.6 are connected. Therefore, the lead wire 6
When electricity is applied to the porous plate 4, the porous plate 4 generates heat, thereby heating the catalyst component supported on the porous plate 4. As a result, a high removal effect can be obtained.

FIG. 3 is a schematic sectional view showing another embodiment of the air cleaner of the present invention. This air purifier is equipped with a fan 2' and an ozone generator 7 inside an air intake port 1''a of an air passage 1'' having the structure shown in the figure, and a plurality of ozone generators installed at an exhaust port 1.'b. A catalyst layer 3'' consisting of a porous plate 4 is provided.

The air purifier of this embodiment generates ozone in the air passage 1', and a baffle plate 8 is provided in the air passage 1' to send the air and ozone in a uniformly mixed state to the catalyst layer 3''. That's what I do.

Hereinafter, the effectiveness of the air purifier of the present invention in removing pollutants from the air will be explained with reference to test examples.

Test Example 1 An air purification test was conducted using the test apparatus shown in FIG. That is, this test device supplies air from a compressor 10 and standard gas containing odor components from a gas cylinder 11 to a mixer 9 and mixes them, and then supplies the obtained test gas to an air purifier 8 to eliminate odor. It is designed to remove components. The air purifier 8 used was the third
Since it is the same as that shown in the figure, the same reference numeral is given and the explanation is omitted. Here, the catalyst layer 3'' was constructed using 20 perforated plates (wire mesh) supporting catalyst components prepared as follows.In addition, in Fig. 4, 12 and 13 are both flowmeters. .

(Preparation of perforated plate) A nichrome wire mesh (wire diameter 200μ, 50 meshes) fired at 300°C for 3 hours was cut into a size of 45cm x 32cm, and two 45cm sides of this wire mesh had a thickness of 0.
．． A 6mm copper plate holder was riveted.

(Preparation of catalyst component) Mn02-TiO2 was used as a catalyst active component. This product was obtained by weighing 800 g and 200 g of electrolytic manganese dioxide and metatitanic acid, respectively, in terms of oxides, mixing them, drying them, baking them at 500° C. for 3 hours, and then pulverizing them in a sample mill.

Next, 100 g of the obtained Mn02-TiO2 was poured into 100 m of silica sol (Snowtex 0 manufactured by Nissan Chemical).
j, alumina sol (Alumina sol 200 manufactured by Nissan Chemical)
Attritor (with 100 mj of water and 100 mj of
The mixture was placed in a grinding media (made by Mikata Mining Co., Ltd., alumina balls with a diameter of 3 mm) and ground for 10 minutes to obtain a catalyst slurry.

(Supporting Catalyst Components on Perforated Plate) The wire mesh was immersed in the catalyst slurry obtained as in 1. After being pulled up, it was dried with hot air in a dryer to coat the surface of the wire mesh with the catalyst.

Then, it was fired at 500°C for 3 hours. As a result, the supporting ratio of the catalyst component on the wire mesh was 17.4%.

(Test gas) Standard gas: 2% ammonia, 0 acetaldehyde
．． Standard gases containing odor components of 2% hydrogen sulfide, 2% hydrogen sulfide, and 0.2% ethyl mercapton were used, and each of these was diluted with air to a predetermined concentration to prepare a test gas.

(Test method) The amount of ozone mixed with the test gas is determined by the odor component concentration (p
The ratio of ozone concentration (ppm) to ozone concentration (ppm) was determined as follows.

(Odor components) (Ozone concentration/test gas concentration) Ammonia 20/10 Acetaldehyde 20/10 Hydrogen sulfide 200/100 Ethyl mercaptan 20/10 The flow rate to the air cleaner 8 was 3 m37 minutes.

In addition, the odor component removal rate was measured with respect to a state where the catalyst temperature was 20° C. without passing any current through each wire mesh constituting the catalyst layer 3′, and a state where the catalyst temperature was heated to 80° C. through a current of 0.92 A.

(Evaluation method of odor component removal rate) The residual amount of each odor component from the test gas that passed through the air cleaner 8 was measured by the following analysis method, and the odor component removal rate was determined from this.

Ammonia: Chemiluminescent ammoniameter Acetaldehyde: FID gas chromatography Hydrogen sulfide: TCD gas chromatography Ethyl mercaptan: FPD gas chromatography The results of these tests are shown in Table 1.

Table 1 Test Example 2 (Durability Test) Using the same test equipment as Test Example 1, after lighting five cigarettes in a closed space and operating the air purifier 8 for one hour, the removal rate of acetaldehyde was evaluated. A comparison was made with the initial performance shown in Table 1 (hereinafter referred to as sample A).

On the other hand, for comparison, an adsorption filter (45 mm) filled with activated carbon (diameter 3 mm, length 3 mm) was used instead of the catalyst layer 3'.
A durability test was conducted in the same manner as Sample A (hereinafter referred to as Sample B), except that a sample (cm x 30 cm x 7 mm) was used. The test results are shown in Table 2.

Table 2 Test Example 3 Tests were conducted in the same manner as in Example 1, except that a catalyst layer using a metal plate having a large number of pores was used instead of the wire mesh. That is, a 200μ thick 5US304 thin plate plated with aluminum to a thickness of about 10μ was fired at 900°C for 3 hours to convert the aluminum into needle-like alumina.

This thin plate was lath-processed to obtain a perforated plate. The catalyst loading rate on this lath processed thin plate was set to 15.7%.

The results are shown in Table 3.

From these Test Examples 1 to 3 in Table 3, it can be seen that the air cleaner of the present invention has excellent removal performance of air pollutants such as odor components, and can maintain its removal effect for a long period of time.

<Effects of the Invention> As described above, in the present invention, since a catalyst layer in which a catalyst component is supported on a perforated plate having predetermined pores is used, the contact area with air is increased, and therefore, the air contact area caused by ozone is increased. The oxidative decomposition reaction of pollutants is carried out efficiently and a high removal effect can be obtained. At this time, the present invention has the advantage that the catalyst layer can be used for a long period of time, and the effort of handling and regeneration is unnecessary, making it easier to handle.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view showing one embodiment of the air purifier according to the present invention, Fig. 2 (a) and crest) are a plan view and a side view of a wire mesh which is a perforated plate, and Fig. 3 is a schematic cross-sectional view showing an embodiment of the air purifier according to the present invention. A schematic sectional view showing another embodiment of the purifier, and FIG. 4 is an explanatory diagram of a test device in a test example.

Claims (1)

[Claims] 1. An air purifier including a catalyst layer provided in an air flow path for mixing ozone with air to promote removal of air pollutants by ozone, wherein the catalyst layer has a diameter of 30 μm. An air purifier comprising a perforated plate having a large number of pores as described above and supporting a catalyst component. 2. The air purifier according to claim 1, wherein the perforated plate is made of a heat generating material, and the catalyst component is heated by passing an electric current through the perforated plate.