JPH0615140A - Deodorizing method - Google Patents

Abstract

PURPOSE:To provide a deodorizing method by which an odorous component in exhaust gas can be efficiently removed for a long time on a catalyst by using ozone. CONSTITUTION:The catalyst used consists of oxides of manganese as the first component and oxides, hydroxides or carbonates of nickel as the second component. An odorous component is decomposed with ozone by using this catalyst. By this method, excellent effect can be obtd. without leaving hamful ozone after deodorization.

Description

Detailed Description of the Invention

FIELD OF THE INVENTION The present invention relates to an odor generating component contained in a gas or the like (hereinafter referred to as "odorous component").
The present invention relates to a deodorizing method for removing.

2. Description of the Related Art Conventionally, as a method for removing odorous components contained in a gas, an adsorption deodorization method using a porous substance such as activated carbon or zeolite, a wet treatment deodorization method using an oxidizing agent or a reducing agent, and ozone decomposition deodorization Various deodorizing methods such as the method have been proposed.

However, it cannot be said that each of the above-mentioned conventional deodorizing methods (hereinafter referred to as "conventional method") is a sufficiently satisfactory deodorizing method. That is, the adsorption deodorization method has a problem that since the adsorbent exerts an adsorption capacity for a limited period of time, the adsorbent needs to be regenerated and the like, and a great deal of labor and cost are required for maintenance of the deodorization device. Further, the wet treatment deodorization method has a problem that treatment of a chemical solution such as an oxidizing agent is complicated. Although the last ozone decomposition deodorization method does not have the above problems,
There have been problems such as insufficient removal of odorous components by oxidative decomposition and the need to decompose ozone contained in the gas after deodorizing treatment in order to prevent pollution such as respiratory disorders. The present invention is to solve these problems that the conventional ozone decomposition deodorization method has, and is superior in the ability to decompose and remove odorous components as compared with the conventional method, and almost all unreacted ozone remains after the deodorization treatment. Various ozone deodorizing catalysts that do not have already been proposed. However, even if these catalysts are used, when the gas contains a small amount of acidic substances such as nitrogen oxides and lower fatty acids, these accumulate in the catalyst or react with the catalyst components, and the catalyst deteriorates or the accumulated odorous substances are generated. The present inventors have found the problem that they are contained in the processing gas. The present invention has been made to solve these problems.

The deodorizing method according to the present invention (hereinafter, referred to as "the present method") for achieving the above object is
The catalyst is characterized by using a manganese oxide as the first component and a nickel oxide, hydroxide or carbonate as the second component. Further, in the constitution of these catalysts, the weight ratio of the first component and the second component is 1
0:90 to 90:10 is preferable, and more preferably 4
It is 0:60 to 80:20. The reason why favorable results are obtained in these ranges is not clear. As such a catalyst, the first component of manganese oxide,
A binary catalyst composed of a combination with a second component nickel oxide, hydroxide or carbonate, for example, MnO ₂ −.
_{NiO, MnO 2 -Ni (OH)} 2, MnO 2 -NiC
O _{3 and the} like can be exemplified. Of these, a preferred catalyst is MnO ₂ —NiO. These catalyst components may be supported on known carriers such as alumina, titania, silica-titania, silica, zirconia and zeolite. Especially, titania with excellent acid resistance,
By supporting it on silica, zirconia, or zeolite support, it is possible to prevent deterioration due to acidic substances such as nitrogen oxides and lower fatty acids, and to prevent the accumulation of odorous substances on the catalyst, and to maintain its deodorizing effect significantly. Became. The loading rate of the catalyst component is usually 0.1 to 50 wt%. This is because if it is 0.1 wt% or less, a sufficient deodorizing effect cannot be obtained, and if it is 50 wt% or more, the ozone decomposing ability is lowered due to pore clogging or the like. The odorous components to be removed by the method of the invention include ammonia, trimethylamine, hydrogen sulfide, methyl mercaptan, methyl sulfide, methyl disulfide, acetaldehyde, styrene, methyl ethyl ketone, acrolein, propionaldehyde, butyl alcohol, phenol, cresol. , Diphenyl ether, acetic acid, propionic acid, valeric acid, methylamine, dimethylamine, skatole, dimethylthioether, dimethylmercaptan, hydrogen chloride, and alkali chloride. Further, as a field in which the method of the present invention is carried out, for example, exhaust gas discharged from living spaces of humans or animals, human waste treatment plants, sewage treatment plants, refuse incineration plants, printing plants, plating plants, general chemical plants, etc. A gas deodorizing process can be mentioned. The shape of the catalyst used in the method of the present invention is not particularly limited, and various shapes such as honeycomb shape, pellet shape, columnar shape, plate shape, pipe shape and the like can be used. The active component content (including the carrier component) in the catalyst is preferably 50% or more, more preferably 75% or more. The catalyst is an impregnation method, a kneading method, a coprecipitation method, a precipitation method,
It can be manufactured by appropriately selecting a known manufacturing method such as an oxide mixing method. In the production of the catalyst, a molding aid may be added to impart shapeability to the catalyst, or a reinforcing agent such as inorganic fiber, an organic binder or the like may be appropriately added to improve mechanical strength and the like. . Ozone (O ₃ ) coexisting with the catalyst at the time of deodorization is used in an appropriate amount depending on the type and concentration of the odorous component to be removed, the reaction temperature, the type and amount of the catalyst, and the like. For example, in the case of a deodorized gas containing H ₂ S as an odorous component, O ₃ per mole of H ₂ S
It is preferable to coexist 1 to 2 moles, and in the case of a deodorized gas containing NH ₃ , O ₃ 1 to 1 mole of NH ₃
It is preferable to coexist 3 mol. Further, in the case of a deodorized gas containing methyl mercaptan, it is preferable that 1 to 4 mol of O ₃ coexist with 1 mol of methyl mercaptan. When the concentration of the odorous component contained in the gas to be deodorized is high, O ₃ may be allowed to coexist in an amount exceeding the above preferable amount in order to improve the removal rate. However, when the amount is too large, excess O ₃ may remain after the deodorizing treatment, and therefore it is necessary to take care not to allow excess O ₃ to coexist in order to prevent such a situation. The reaction temperature for deodorization is 0 to 40 ° C.
Is preferable, and 10-30 degreeC is more preferable. This is because if the temperature is lower than 0 ° C, the reaction rate becomes slow, and if the temperature exceeds 40 ° C, new energy is required for raising the temperature, which is uneconomical. However, it goes without saying that the method of the present invention can process these gases when the gas temperature is 40 ° C. or higher. Further, the contact between the catalyst and the reaction gas is preferably performed at an area velocity (AV: area Velocity) of 5 to 50. This is because if the area velocity is less than 5, a large amount of catalyst is required, and if the area velocity exceeds 50, the efficiency is low and a predetermined decomposition rate cannot be obtained. Here, the area velocity is a value obtained by dividing the reaction amount (Nm ³ / u, u: Hr) by the gas contact area (m ² / m ³ ) per unit volume of the catalyst.

EXAMPLES The present invention will be described in detail below based on examples. However, the present invention is not limited to the following examples. A. Preparation of Catalyst Example 1 Water and glass beads were added to 100 g of MnO ₂ having a specific surface area of 135 m ² / g and 100 g of NiO having a specific surface area of 187 m ² / g, and the mixture was stirred and mixed for 30 minutes to form a slurry.
A corrugated honeycomb made of ceramic fibers having a porosity of 81% and a pitch of 4.0 mm was impregnated with this slurry to carry MnO ₂ —NiO (weight ratio 50:50) at a supporting rate of 6
A binary catalyst supported at 8% was obtained. Example 2 In Example 1, Ni (O) was used instead of 100 g of NiO.
H) ₂ N in the same manner as in Example 1 except that 100 g is used.
iO—Ni (OH) ₂ (weight ratio 50:50) was loaded on a support ratio of 7
A binary catalyst supported at 1% was obtained. Example 3 In Example 1, NiCO ₃ was replaced with NiO 100 g.
MnO ₂ was prepared in the same manner as in Example 1 except that the amount was 100 g.
A two-way catalyst supporting NiCo ₃ (weight ratio 50:50) at a supporting rate of 76% was obtained. Example 4 In Example 1, 20 g instead of 100 g of MnO ₂ ,
MnO ₂ —NiO (weight ratio 10:90) was performed in the same manner as in Example 1 except that the amount of NiO was changed to 180 g instead of 180 g.
Thus, a two-way catalyst having a supported ratio of 66% was obtained. Example 5 In Example 1, 60 g instead of 100 g of MnO ₂ ,
MnO ₂ —NiO (weight ratio 30:70) was carried out in the same manner as in Example 1 except that the amount of NiO was changed to 140 g instead of 100 g.
Thus, a two-way catalyst supporting 65% of was obtained. Example 6 In Example 1, 180 g instead of 100 g of MnO ₂ .
g, NiO 100 g, and 20 g instead of NiO 100 g in the same manner as in Example 1 MnO ₂ —NiO (weight ratio 90: 1
A binary catalyst carrying 0) at a loading rate of 72% was obtained. Example 7 In Example 1, 140 g was used instead of 100 g of MnO _2.
g, MnO ₂ —NiO (weight ratio 70: 3) in the same manner as in Example 1 except that 60 g was used instead of NiO 100 g.
A binary catalyst carrying 0) at a loading rate of 72% was obtained. Example 8 In Example 7, Ni (OH) was used instead of NiO 60 g.
Except that the ₂ 60 g, in the same manner as in Example 7 MnO ₂
-Ni (OH) ₂ (weight ratio 70:30) is supported 72%
A two-way catalyst supported by was obtained. Example 9 Example 7, NiCO ₃ 6 instead of NiO60g
MnO ₂ —N was prepared in the same manner as in Example 7 except that the amount was 0 g.
A two-way catalyst supporting iCO ₃ (weight ratio 70:30) at a supporting rate of 68% was obtained. Comparative Example 1 A one-way catalyst carrying MnO ₂ at a loading rate of 76% was obtained in the same manner as in Example 1 except that 200 g of MnO ₂ was used in Example 1 and NiO was not added. B. Catalyst activity test The catalysts obtained in the above Examples 1 to 9 and Comparative Example 1 were subjected to a catalyst activity test under the following reaction conditions using a test apparatus whose flow sheet is shown in FIG. In the figure,
(1) is a catalyst layer, and the odorous component contained in the deodorized gas introduced into the catalyst layer (1) is an ozone generator (2).
It is decomposed by ozone (O ₃ ) guided to the catalyst layer (1). A part of the gas after the decomposition and deodorization is guided to the ozone analyzer (3) where the residual ozone (O ₃ ) is quantitatively analyzed. The rest of the gas after decomposition and deodorization is led to the odorous component analyzer (4). The odorous component analyzer (4)
It is composed of a gas chromatograph, and the quantitative analysis of each of the odorous components is performed by these instruments. The ozone decomposition rate (%) and the odorous component decomposition rate (%) are calculated from the concentrations at the inlet and outlet of the catalyst layer (2) measured by the ozone analyzer (3) and the odorous component analyzer (4), respectively. It is calculated using the following formula. (Reaction conditions) Space velocity: 20000 / Hr Reaction temperature: 20 ° C. Inlet ozone concentration: 10 ppm Odorous components Methylcaptan, methylamine, acetaldehyde, ammonia, hydrogen sulfide: 5 ppm each, propionic acid: 1 ppm Under these conditions, initial 100 hours After 1,000 hours, the decomposition rate of each ozone and odorous component was measured to examine the deterioration of the catalyst. The results are shown in Table-1. As is clear from the above table, the catalysts obtained in Examples 1 to 9 maintain high ozone and odorous component decomposition rates (%) over a long period of time, as compared with Comparative Example 1. From the above test results, it is understood that the method of the present invention is a deodorizing method capable of maintaining the ozone and odorous component decomposition rate (%) at a high level for a long time.

The ozone decomposing and deodorizing method according to the present invention is capable of efficiently removing odorous components for a long time, and has almost no harmful ozone remaining in the respiratory system after the deodorizing treatment. Has an excellent and unique effect.

[Brief description of drawings]

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

Claims (1)

[Claims] In the method of catalytically oxidatively decomposing an odorous component on a catalyst using ozone, the catalyst is a manganese oxide as a first component,
A deodorizing method characterized by using, as the second component, one composed of nickel oxide, hydroxide or carbonate.