JPH0564654A - Deodorizing method - Google Patents

Abstract

PURPOSE:To provide a deodorizing method which decomposes an odorous component in an exhaust gas on a catalyst using ozone. CONSTITUTION:Catalyst herein used is composed of one or more of oxides of Mn, Fe, Co, Ni, Cu and Ag as first component, oxide, hydroxide or carbonate of alkali or alkaline earth metal as second component and activated charcoal as third component. The catalyst is used to decompose an odorous component by ozone. This enables efficient deodorizing of the odorous component in an exhaust gas thereby achieving excellent effect.

Description

Detailed Description of the Invention

BACKGROUND 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, ozone decomposition deodorization Various deodorizing methods such as a method have been proposed.

However, it is hard to say that any of the above conventional deodorizing methods (hereinafter referred to as "conventional methods") are sufficiently satisfactory deodorizing methods. That is, the adsorption deodorization method has a problem that since the adsorbent exhibits a limited adsorption capacity for a limited period of time, the adsorbent needs to be regenerated, and a great deal of labor and cost is 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 the 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 decomposing deodorizing catalysts have already been proposed. However, even if these catalysts are used, when a small amount of acidic substances such as nitrogen oxides and lower fatty acids are contained in the gas, these are accumulated in the catalyst or react with the catalyst components to deteriorate the catalyst or generate odorous substances. 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 method of the present invention") for achieving the above object is as follows:
The first component of the catalyst is Mn, Fe, Co, Ni, Cu,
At least one selected from oxides of Ag, an oxide of an alkali or alkaline earth metal as the second component,
It is characterized by using a hydroxide or a carbonate, and a third component composed of activated carbon. In the constitution of these catalysts, the weight ratio of the first component and the second component is preferably 100: 0.1-50, more preferably 10: 0.1-50.
0: 0.5 to 25, and the total weight ratio of the first component and the second component to the third component is 5 to 100: 100, preferably 20 to 50: 100. The reason why favorable results are obtained in these ranges is not clear. As such a catalyst, each oxide of the first component,
A binary catalyst composed of a combination of respective oxides, hydroxides or carbonates of the second component and an active carbon of the third component as a main component, for example, MnO ₂ -CaO-activated carbon,
MnO ₂ -Ca _{(OH) 2} - activated _carbon, MnO 2 -CaC
O ₃ - activated carbon, NiO-MgO- activated carbon, NiO-Mg
_{(OH) 2} - activated carbon, NiO-MgCO ₃ - activated carbon, N
i ₂ O ₃ -SrO- activated _{carbon, Ni 2 O-Sr (OH} ) 2
- activated _carbon, Ni ₂ O ₃ -SrCO 3 - activated carbon, _Co 2 O
₃ -BaO- activated _{carbon, Co 2 O 3 -Li (OH} ) 2 - activated _carbon, Co ₂ O ₃ -LiCO 3 - and two or more of the respective oxides of the activated carbon and the like, and the first component, the second
Those containing as a main component a multi-way catalyst consisting of a combination of one or more of respective oxides, hydroxides or carbonates of the components and activated carbon as the third component, for example Mn.
_{O 2 -Ag 2 O-CaCO 3} - activated _carbon, MnO 2 -Ag
_{2 O-Ca (OH) 2} - activated _carbon, MnO 2 -NiO-K
₂ O-activated carbon, MnO ₂ -NiO-KOH-activated carbon, M
_{nO 2 -NiO-K 2 CO 3} - active _carbon, MnO 2 -Co
₂ O ₃ -BaO- activated _carbon, MnO ₂ -Co ₂ O 3 -Ba
_{(OH) 2} - activated _carbon, MnO ₂ -Co ₂ O 3 -BaCO
₃ - activated _{carbon, Ni 2 O 3 -Ag 2 O} -Na 2 O- activated _{carbon, Ni 2 O 3 -Ag 2 O} -NaOH- activated carbon, Ni _{2
O 3 -Ag 2 O-Na 2} CO 3 - activated carbon or the like can be exemplified. Among these, preferred catalysts are M
nO ₂ -Li ₂ CO ₃ - active _carbon, MnO 2 CaCO ₃
- activated _carbon, Ag 2 O-CaCO ₃ - active carbon, MnO ₂ -
SrCO ₃ - activated _carbon, MnO 2 -BaCO ₃ - activated carbon,
Ni ₂ O ₃ -CaCO ₃ - activated _carbon, MnO 2 _-Ag 2 O
-CaCO ₃ - activated _{carbon, Ni 2 O 3 -Ag 2 O} -CaC
O ₃ -activated carbon and the like can be mentioned. These catalyst components are
It may be supported on known carriers such as alumina, titania, silica-titania, silica, zirconia, and zeolite. In particular, by supporting it on titania, silica-titania, silica, zirconia, or zeolite carrier, which has excellent acid resistance, 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. , It became possible to maintain its deodorizing effect significantly. 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 are 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, waste incineration plants, printing plants, plating plants, general chemical plants, etc. A gas deodorizing process may 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 ingredient 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 an 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 during 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 mol of H ₂ S
It is preferable to coexist with 1 to 2 mol, and in the case of a deodorized gas containing NH ₃ , O ₃ 1 to 1 mol of NH ₃
It is preferable to coexist 3 mol. Further, in the case of a deodorized gas containing methyl mercaptan, it is preferable to coexist 1 to 4 mol of O ₃ per 1 mol of methyl mercaptan. When the concentration of the odorous component contained in the deodorized gas is high, O ₃ may be allowed to coexist in an amount exceeding the above-mentioned preferable amount in order to improve the removal rate. However, if the amount is too large, excess O ₃ may remain after the deodorization process, so 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 70 g of NiO and 20 g of CaO having a specific surface area of 127 m ² / g
To 180 g of Shirasagi A activated carbon manufactured by Takeda Pharmaceutical Co., Ltd., water and glass beads were added, and the mixture was stirred and mixed for 30 minutes to form a slurry. This slurry was impregnated into a corrugated honeycomb made of ceramic fibers having a porosity of 81% and a pitch of 4.0 mm, and NiO-CaO-activated carbon (weight ratio 70:20:
180) with a loading rate of 72% to obtain a three-way catalyst. Example 2 In Example 1, Ca (OH) was used instead of 20 g of CaO.
Except that the ₂ 20 g, in the same manner as in Example 1 NiO
Ca (OH) ₂ -activated carbon (weight ratio 70: 20: 180)
To give a three-way catalyst carrying 64%. Example 3 In Example 1, CaCO ₃ 2 was used instead of CaO 20 g.
NiO-Ca in the same manner as in Example 1 except that the amount is 0 g.
A three-way catalyst supporting CO ₃ -activated carbon (weight ratio 70: 20: 180) at a supporting rate of 67% was obtained. Example 4 In Example 1, 20 g of CaO was replaced with Na ₂ CO _3.
NiO—N in the same manner as in Example 1 except that the amount is 10 g.
A _two- way catalyst carrying a ₂ CO ₃ -activated carbon (weight ratio 70: 10: 180) at a loading rate of 55% was obtained. Example 5 In Example 1, K ₂ CO ₃ 1 was used instead of CaO 20 g.
NiO-K _{2 was} prepared in the same manner as in Example 1 except that the amount was 0 g.
A three-way catalyst carrying CO ₃ -activated carbon (weight ratio 70: 10: 180) at a loading rate of 63% was obtained. Example 6 In Example 1, MgCO ₃ 2 was used instead of CaO 20 g.
NiO-Mg was prepared in the same manner as in Example 1 except that the amount was 0 g.
A three-way catalyst supporting CO ₃ -activated carbon (weight ratio 70: 20: 180) at a supporting rate of 69% was obtained. Example 7 In Example 1, SrCO ₃ 2 was used instead of CaO 20 g.
NiO-Sr was prepared in the same manner as in Example 1 except that the amount was 0 g.
A three-way catalyst supporting CO ₃ -activated carbon (weight ratio 70: 20: 180) at a supporting rate of 72% was obtained. Example 8 In Example 1, instead of CaO 20 g, BaCO ₃ 2
NiO-Ba was manufactured in the same manner as in Example 1 except that the amount was 0 g.
A three-way catalyst supporting CO ₃ -activated carbon (weight ratio 70: 20: 180) at a supporting rate of 69% was obtained. Example 9 In Example 3, the specific surface area 48 was changed to 70 g of NiO.
MnO ₂ -CaCO ₃ -activated carbon (weight ratio 70: 70: m ² / g of MnO ₂ 70 g) was used in the same manner as in Example 3.
20: 180) with a loading rate of 71% to obtain a three-way catalyst. Example 10 In Example 3, Co ₂ O ₃ 7 was used instead of NiO 70 g.
Co ₂ O ₃ − in the same manner as in Example 3 except that the amount was 0 g.
A three-way catalyst carrying CaCO ₃ -activated carbon (weight ratio 70: 20: 180) at a loading rate of 68% was obtained. Example 11 In Example 3, MnO ₂ 35 was used instead of NiO 70 g.
g, NiO 35 g, MnO ₂ —NiO—CaCO ₃ —activated carbon (weight ratio 35:
35: 20: 180) with a loading rate of 72% to obtain a four-way catalyst. Example 12 In Example 3, MnO ₂ 60 was used instead of NiO 70 g.
g, Ag ₂ O 10 g, MnO ₂ —Ag ₂ O—CaCO ₃ —activated carbon (weight ratio 6).
0: 10: 20: 180) was obtained at a loading rate of 65% to obtain a four-way catalyst. Example 13 MnO ₂ —CaCO ₃ — was prepared in the same manner as in Example 3 except that the weights of MnO ₂ , calcium carbonate and activated carbon were 80 g, 5 g and 170 g, respectively.
A three-way catalyst carrying activated carbon (weight ratio 100: 6.25: 212.5) at a loading rate of 78% was obtained. Example 14 MnO ₂ —CaCO ₃ was performed in the same manner as in Example 3 except that the weights of MnO ₂ , calcium carbonate, and activated carbon were changed to 8 g, 0.5 g, and 170 g, respectively.
-A three-way catalyst carrying activated carbon (weight ratio 1: 0.0625: 21.25) at a loading rate of 53% was obtained. Example 15 MnO ₂ —CaCO ₃ -activated carbon (weight ratio 100: 100) was obtained in the same manner as in Example 3 except that the weights of MnO ₂ , calcium carbonate, and activated carbon were changed to 80 g, 5 g, and 80 g, respectively. 6.25: 100) carrying rate 81
% Of the supported three-way catalyst was obtained. Comparative Example 1 NiO was set in the same manner as in Example 1 except that 100 g of NiO was used and CaO and activated carbon were not added.
To obtain a one-way catalyst supporting 95% of the catalyst. Comparative Example 2 100 g of MnO _{2 in} Example 9, CaCO ₃ ,
A one-way catalyst supporting MnO ₂ at a supporting rate of 100% was obtained in the same manner as in Example 1 except that activated carbon was not added. Comparative Example 3 In Example 10, 100 g of Co ₂ O ₃ was used, and CaCO
₃ , except that the activated carbon was not added, in the same manner as in Example 10 to obtain a one-way catalyst carrying Co ₂ O ₃ at a loading rate of 100%. Comparative Example 4 MnO ₂ —NiO (weight ratio 50: 5 was used in the same manner as in Example 11) except that 50 g of MnO _{2 and} 50 g of NiO were used in Example 11, and CaCO ₃ and activated carbon were not added.
A binary catalyst carrying 0) at a loading rate of 99% was obtained. Comparative Example 5 MnO ₂ -Ag ₂ O (weight ratio 90: 90) was used in the same manner as in Example 12 except that 90 g of MnO _{2 and 10} g of Ag ₂ O were used in Example 12, and CaCO ₃ and activated carbon were not added.
A two-way catalyst supporting 10) at a supporting rate of 103% was obtained. Comparative Example 6 MnO ₂ —CaCO ₃ was performed in the same manner as in Example 3 except that the weights of MnO ₂ , calcium carbonate, and activated carbon were changed to 80 g, 5 g, and 42.5 g in the method of Example 9.
-A three-way catalyst carrying activated carbon (weight ratio 100: 6.25: 53.125) at a loading rate of 65% was obtained. Comparative Example 7 MnO ₂ —CaCO ₃ was performed in the same manner as in Example 3 except that the weights of MnO ₂ , calcium carbonate, and activated carbon were 80 g, 40 g, and 240 g, respectively, in the method of Example 9.
-A three-way catalyst carrying activated carbon (weight ratio 10: 5: 30) at a loading rate of 65% was obtained. Comparative Example 8 In the method of Example 9, the weights of MnO ₂ , calcium carbonate, and activated carbon were 80 g, 0.07 g, and 160 g, respectively.
MnO ₂ —CaC as in Example 3 except that
O ₃ -activated carbon (weight ratio 100: 0.0875: 200)
To obtain a three-way catalyst supporting 61%. B. Catalyst activity test The catalysts obtained in the above Examples 1 to 15 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 components contained in the deodorized gas introduced into the catalyst layer (1) are conducted from the ozone generator (2) to the catalyst layer (1). It is decomposed by the burned ozone (O ₃ ).
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 remaining gas after decomposition and deodorization is the odorous component analyzer (4).
Be led to. The odorous component analyzer (4) is composed of a gas chromatograph, and the odorous components are quantitatively analyzed by these instruments. 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) using the following formulas. To be done. (Reaction conditions) Space velocity: 20000 / Hr Reaction temperature: 20 ° C. Inlet ozone concentration: 10 ppm Odorous component 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 15 maintain high ozone and odorous component decomposition rates (%) over a long period of time as compared with Comparative Examples 1 to 8. 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 / deodorizing method according to the present invention can efficiently remove odorous components for a long period of time, and hardly leaves harmful ozone in the respiratory system after 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 uses Mn, Fe, Co, and
Use of at least one selected from oxides of Ni, Cu and Ag, an oxide or hydroxide or carbonate of an alkali or alkaline earth metal as the second component, and activated carbon as the third component. Deodorizing method characterized by.