JPH02180638A - Deodorizing catalyst - Google Patents

Abstract

PURPOSE:To remove a smelly component with good efficiency and with little amount of harmful ozone remaining by carrying a catalyst active component of given thickness and effective for deodorizing reaction by ozone on an inactive carrier. CONSTITUTION:10-200mu of a catalyst active component such as MnO2-TiO2, MnO2-SiO2 or the like is carried on an inactive carrier such as ceramic-fiber made corrugated honeycomb, cordierite honeycomb or the like for a catalyst oxidative decomposing a smelly component in gas or the like by means of ozone. Adsorption saturated quantity of smelly component to said catalyst is properly adjusted by said arrangement, and the smelly component can be removed even if conditions of temperature, concentration and the like are changed. Ozone remains scarcely after deodorizing treatment.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention removes odor-producing components contained in gases (hereinafter referred to as "odorous components") by oxidizing and decomposing them with ozone. This invention relates to a deodorizing catalyst for deodorizing.

<Prior art> Conventional methods for removing odorous components contained in gas include adsorption deodorization using porous materials such as activated carbon and zeolite, wet processing deodorization using oxidizing agents or reducing agents, and ozonolysis deodorization. Various deodorizing methods have been proposed.

<Problems to be Solved by the Invention> However, it is difficult to say that each of the deodorizing methods described in 1 above (hereinafter referred to as "conventional methods") is a fully satisfactory deodorizing method.

That is, the adsorption deodorization method has a problem in that since the period during which the adsorbent exhibits its adsorption capacity is limited, it requires regeneration, etc., and maintenance of the adsorption device requires a great deal of labor and cost.

In addition, the wet deodorization method has a problem in that processing of chemical solutions such as oxidizing agents is complicated.

Although the last ozonolysis deodorization method does not have the above-mentioned problems, the removal of odorous components by oxidative decomposition is insufficient, and in order to prevent pollution such as respiratory disorders, there are some problems in the gas after deodorization. There are problems such as the need to decompose the ozone contained.

The present inventors have already proposed various deodorizing catalysts using ozone. They are effective in this reaction as catalytic active components, but in ozone deodorization reactions where reaction conditions vary, the Solirad-type catalysts conventionally used adsorb and saturate a large amount of malodorous components, resulting in: ■ an increase in the reaction temperature; There has been a problem in that when conditions change, such as from a high concentration condition to a low concentration condition, malodorous components exceeding the malodor resolving power are released into the gas, causing a malodor.

The present invention was made to solve these problems that the conventional ozonolysis deodorization method had, and its purpose is to improve the ability to decompose and remove odorous components compared to the conventional method. It is an object of the present invention to provide an ozone decomposition deodorization method that is obsolete and leaves almost no unreacted ozone after deodorization treatment.

Means for Solving the Problem> Catalysts used in the ozone deodorization reaction according to the present invention to achieve the above object are effective for this reaction, including those already proposed by the present inventors. It is characterized by supporting 10 to 200 μ of a catalytically active component on an inert carrier.

The odorous components to be removed by the method of the present invention include ammonia, trimethylamine, hydrogen sulfide, methyl mercaptan, methyl sulfide, methyl disulfide, acetaldehyde, styrene, methyl ethyl ketone, acrolein,
Examples include propionaldehyde, butyl alcohol, phenol, cresol, diphenyl ether, acetic acid, propionic acid, valeric acid, methylamine, dimethylamine, skatole, dimethylthioether, dimethylmercaptan, hydrogen chloride, and allyl chloride.

Fields in which the method of the present invention is implemented include, for example, deodorizing treatment of exhaust gas discharged from human waste treatment plants, sewage treatment plants, garbage incineration plants, printing factories, Metsuki factories, general chemical factories, etc.

Next, as the active component of the catalyst used in the present invention, as already proposed by the present inventors, Mn02
-TiO2, MnO2-5i02, CuO-TiO2,
Co30. -Tie2, Fe203-Tie. , F e
203-Those whose main component is a binary catalyst such as Au and M
n02-Co30a-Tie2, MnO2-Co30
Examples include those whose main component is a three-way catalyst such as a-Ag 20, Ni0-Mn0□-TiO□.

In addition, as inert carriers supporting these active ingredients,
Corrugated honeycombs made of ceramic fibers, honeycombs made of cordierite, clay etc. molded into various shapes may be used. The shape of this molded body is not particularly limited, and various shapes such as a honeycomb shape, a pellet shape, a cylindrical shape, a plate shape, and a vibrator shape can be used.

In addition, at this time, a molding aid may be added to give the carrier shapeability, and reinforcing agents such as inorganic fibers, organic binders, etc. may be added as appropriate to improve mechanical strength etc. . The catalyst used in the present invention can be obtained by cutting the carrier formed in this way and supporting 10 μ to 200 μ of the above-mentioned active ingredient. When the supported amount is within the above range, the adsorption saturation of malodorous components on this catalyst The amount of malodor is adjusted to the optimum level, improving stability against fluctuations in conditions such as: (1) raising the reaction temperature, (2) changing from a high odor condition to a low odor condition, and releasing malodorous components that exceed the malodor resolution into the gas. Issues such as: When the supported amount exceeds the above range, the adsorption saturation amount of malodorous components increases,
When conditions fluctuate as described above, malodorous components may be released into the gas, which may conversely become a source of malodor, which is undesirable. Furthermore, if the supported amount is below the above range, the malodor decomposition ability itself will be lowered, which is also undesirable.

Ozone (03), which is allowed to coexist with the above catalyst during deodorization, is used as appropriate depending on the type and strength of the odorous component to be removed, the reaction temperature, the type and amount of the catalyst, etc. For example, in the case of a gas to be deodorized containing H2S as an odorous component, it is preferable to allow 031 to 2 mol per mol of H2S to coexist, and in the case of a gas to be deodorized containing NH3,
It is preferable to coexist in an amount of 0.31 to 3 moles per mole of NH. In addition, in the case of a gas to be deodorized containing methyl mercaptan, 031 per mole of methyl mercaptan
It is preferable to coexist in an amount of 4 mol to 4 mol.

When the concentration of odorous components contained in the gas to be deodorized is high, 03 may be present in an amount exceeding the above-mentioned suitable amount in order to improve the removal rate. However, if there is too much 03, excess 03 may remain after the deodorizing treatment, so care must be taken not to allow excess 03 to coexist to prevent this from happening.

The reaction temperature during deodorization is preferably 0 to 40°C, and 10 to 40°C.
30°C is more preferred. This is because if the temperature is less than 0°C, the reaction rate becomes slow, and if it exceeds 40°C, additional energy is required to raise the temperature, which is uneconomical.

Further, the contact between the catalyst and the reaction gas is preferably performed at an area velocity (AV) of 5 to 50. This is because if the areal velocity is less than S, a large amount of catalyst is required, and if the areal velocity exceeds 50, the efficiency is low and a predetermined decomposition rate cannot be obtained. Here, the areal velocity is the reaction ffi (Nm'/u, u:
Hr) is the gas contact area per unit volume of catalyst (1n'
/m').

<Examples> Hereinafter, the present invention will be described in detail based on Examples. However, the present invention is not limited to the following examples.

A. Catalyst Ω dish type Example 1 After drying Kibushi clay at 100° C. for 18 hours, it was pulverized in a sample mill with a screen of 0.5 mmφ. 20 kg of these pulverized materials were added to a methyl cellulose binder (
1 kg of Nihon Kogyo YB-32) and water were added, mixed, and thoroughly kneaded in a kneader.

These clay materials were put into an auger screw type extruder equipped with a die for honeycomb extrusion, and a honeycomb-like product was extruded. Moisture was adjusted so that the pressure at this time was 30 to 35 kg/C♂. After drying the obtained honeycomb-like material at room temperature with ventilation, the temperature was raised to 500 °C at a temperature increase rate of 5 °C / hour, and after being kept for 3 hours, the temperature was lowered at a temperature decrease rate of 10 °C / hour. After cooling, a honeycomb-shaped carrier having an aperture ratio of 64% and a pitch of 4.0 mm was obtained.

Next, 704 g of MnO2 with a specific surface area of 48+tl'/g
Titania sol (T10□ containing n: 150g/u) 10
34w+Q plus 250g of glass peas
After stirring and mixing for 30 minutes, separate the beads.
Got slurry. After diluting this slurry by adding 300 g of water, the above-mentioned honeycomb-shaped carrier cut into an appropriate size was immersed in the slurry, excess slurry was removed, and after drying, it was calcined at 500°C for 3 hours. , Mn02-TiO
A binary catalyst was obtained in which two layers (weight ratio 82:18) were supported with an average thickness of 10 μm. Note that the thickness of this support layer was measured by XPS. The aperture ratio of this catalyst is 63%, and the gas contact area per unit volume (hereinafter referred to as rApJ) is 795T.
It was 11"/-.

Example 2 In Example 1, the opening ratio was 6 in the same manner as in Example 1 except that the Mn02-TiO9 supporting layer was 50μ on average.
A binary catalyst with Ap 775m'/- was obtained.

Example 3 In the same manner as in Example 1, except that the Mn02-TiO2 sol slurry was not diluted with water and the rvInO2-TiO2 support layer was made to have an average of 100μ, the aperture ratio was 56% and Ap750 A binary catalyst of tn'/- was obtained.

Example 4 In Example 1, MnO2-T i O. Run 1ff111 except that the sol slurry was not diluted with water and the Mn02-TiO□ support layer was made to have an average thickness of 200μ.
Similarly, the aperture ratio is 49% and Ap7001TI'/
n? A two-way catalyst was obtained.

Comparative Example 1 In Example 1, the opening ratio was 64 in the same manner as in Example 1 except that the MnO□-TiO2 supporting layer was 5μ on average.
%, Ap 798 m'/m' of the binary catalyst.

Comparative Example 2 In the same manner as in Example 1, except that the Mn02-TiO□ sol slurry was not diluted with water and the Mn02-TiO3 support layer was made to have an average of 250 μm, the opening ratio was 46%, A binary catalyst of Ap675 t112/T11' was obtained.

A three-way catalyst supported at 100% was obtained.

Comparative Example 3 29.27 kg of Mn with specific surface TUssm of 7 g was added with 29.27 g of titania sol (150 g/inclusive), thoroughly kneaded, dried up, fired at 500°C for 3 hours, and after cooling, the screen became 0. Grinded with a 5 mmφ sample mill, MnO, -Tie, weight ratio 82:18
A fired powder was obtained. 20 kg of these pulverized materials, methyl cellulose binder (YUKENE, ff1YB-32)
11. g and water were added, mixed, and thoroughly kneaded using a kneader. These clays were put into an auger screw type extruder equipped with a die for honeycomb extrusion, and a honeycomb-shaped catalyst was extruded.

The pressure at this time is 30-35! Moisture content was adjusted so that it was g/cm'. After drying the obtained honeycomb-shaped catalyst at room temperature with ventilation, the temperature was raised to 500 °C at a temperature increase rate of 5 °C / hour, kept at a temperature increase rate of 3 hours, and then cooled at a temperature decrease rate of 10 °C / hour. A two-way catalyst with an aperture ratio of 63% and Ap795+n'/back was obtained.

B. Catalytic activity test Each of the catalysts obtained in Examples 1 to 4 and Comparative Examples 1 to 3 above was subjected to a catalytic activity test under the following reaction conditions using the test method whose flow sheet is shown in Figure 1. . In the figure, (1) is an ozone generator, and odorous components H2S and NH contained in the gas to be deodorized introduced into the catalyst layer (2).
3 and methylamine are decomposed by ozone (03) introduced from the ozone generator (1) to the catalyst layer (2).

A portion of the gas after decomposition and deodorization is led to an ozone analyzer (3), where residual ozone (03) is quantitatively analyzed. In addition, the remaining gas after decomposition and deodorization is collected using an odorous component analyzer (4
). The odor component analyzer (4) consists of two gas chromatographs (H2S or methylamine analyzer) and NH
It consists of one 3-meter unit, and quantitative analysis of each of the above-mentioned odorous components is performed using these devices.

(Reaction conditions I) Space velocity: 20000/Hr Reaction temperature: 20°C Odorous component concentration/ozone concentration H2S103: 10/20ppmNHalo 3
: 10/30ppm methyl mercaptan 103:
5/10 ppm (reaction condition ■) After 24 hours under reaction condition I, the reaction temperature was raised from 20°C to 50°C, and measured 5 minutes after the temperature was raised.

(Reaction Conditions ■) After 24 hours under the reaction conditions (■), the concentrations of odorous components were changed as shown below, and the measurements were taken after 5 minutes.

H2S1a degree: 1ppm N H35 degrees: lppm Methyl mercaptan: 1pp+n The above test results are shown in Table 1.

As is clear from the above results in Table 1, all the catalysts obtained in Examples 1 to 4 were more sensitive to reaction conditions (1) and condition fluctuations such as In, compared to the catalysts obtained in Comparative Examples 1 to 3. It has a high and stable odor component removal rate. From these results, the deodorizing catalyst according to the present invention has a high and stable odorous component removal rate even when conditions change, such as (1) an increase in reaction temperature, (2) a change from a high odor component concentration condition to a low odor component concentration condition. You can see that

<Effects of the Invention> The ozone decomposition and deodorization method according to the present invention can efficiently remove odor components, and the present invention has excellent advantages such as almost no ozone harmful to the respiratory system remaining after the deodorization treatment. It has a unique effect.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet of the catalyst activity test. (1) Ozone generator (2) Catalyst layer (3) Ozone analyzer (4) Odorous component analyzer Figure 1

Claims (1)

[Claims] In a deodorizing method characterized by removing odorous components by oxidative decomposition with ozone in the presence of a catalyst,
The active component of the catalyst is deposited on an inert support in an amount of 10μ to 200μ
A deodorizing catalyst characterized by supporting μ.