JP3395669B2 - Deodorizing device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deodorizing device, and more particularly to a device for efficiently decomposing a sulfur-based odor generated in a sewage treatment plant by the oxidizing power of ozone.

[0002]

2. Description of the Related Art Sulfur-based odor generated in sewage treatment plant sewage or sludge treatment equipment (hydrogen sulfide (H
₂ S), methyl mercaptan (CH ₃ SH), methyl sulfide (including (CH ₃ ) ₂ S, methyl disulfide ((CH ₃ ) ₂ S ₂ ), etc.) is used as a deodorizing method by utilizing the oxidizing power of ozone There is known an ozone deodorizing method for deodorizing odorous components. This ozone deodorization method is a dry method in which ozone gas is directly blown into the odor gas to decompose the odor components by air-gas contact (Japanese Patent Laid-Open No. Sho 5).
No. 2-135869) and a wet method in which ozone-dissolved water is sprinkled into a packed tower in which odorous gas is flowing upward, and odorous components are decomposed by gas-liquid contact (JP-A-57-167723). There is. The packing material for the packed tower used in the wet method is merely for improving the gas-liquid contact efficiency, and is made of a ceramic material or a plastic material.

[0003]

In the conventional deodorization method by dry ozone oxidation, the reaction efficiency of the decomposition reaction by gas-gas contact is extremely low, and the removal rate of odorous components is about 20% at the most. The usage efficiency is also very low, about 20%.

On the other hand, in the deodorization method by wet ozone oxidation, the reaction efficiency of the decomposition reaction by gas-liquid contact is high,
For this reason, the aeration air velocity (SV) of the odor vented to the packed tower
It is possible to perform deodorizing treatment with a relatively high load of 600 to 1000 hr ^-1 , but in situations where it is always desired to downsize the equipment and shorten the treatment time, further improvement in reaction efficiency is required. There is.

The present invention has been made in view of the above-mentioned conventional circumstances, and is a deodorizing apparatus by wet ozone oxidation, which has a remarkably high deodorizing efficiency, and is capable of downsizing the equipment and improving the processing efficiency. The purpose is to provide a device.

[0006]

The deodorizing apparatus of the present invention comprises means for producing ozone-dissolved water, a deodorizing tower filled with a catalyst, means for upwardly flowing odor into the deodorizing tower, and the deodorizing tower. It is characterized by comprising means for spraying ozone-dissolved water from the upper part of the inside and means for decomposing residual ozone in the exhaust gas discharged from the deodorization tower.

In the present invention, upon deodorization by wet ozone oxidation, the presence of a catalyst causes ozone to act in an equimolar amount with respect to sulfur (S), which is a sulfur-based odor component, as shown in the following reaction formula. By doing so, it becomes possible to decompose efficiently, and the reaction efficiency and ozone utilization efficiency can be improved.

H ₂ S + O ₃ → H ₂ O + SO ₂ (CH ₃ ) ₂ S ₂ + 2O ₃ → 2CH ₃ O + 2SO _{2 In} the deodorizing apparatus of the present invention, ozone-dissolved water is produced with an ozone-dissolving efficiency of 95% or more. By contacting water countercurrently in the presence of odor and a catalyst, SV1000-200
Even with high load treatment of ⁰ hr ^-1 , ozone usage rate is 99% or more,
It is possible to achieve an odor component removal rate of 99.9% or more,
The capacity of the deodorization tower can be reduced to about 1/2 of that of the conventional deodorization method using wet ozone oxidation, and efficient deodorization can be performed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a system diagram showing an embodiment of a deodorizing apparatus of the present invention.

An oxygen generator 1 is provided for increasing the oxygen concentration of the raw material air and reducing the capacity of the ozonized air obtained by the ozone generator 2. The air whose oxygen concentration has been increased by the oxygen generator 1 is fed to the ozone generator 2 to generate ozone and obtain ozonized air.

The ozonized air is supplied to the ozone dissolution tower 3 through the pipe 11, diffused and stirred from the diffuser pipe 3A at the bottom of the tower, and dissolved in water. In this ozone dissolution tower 3, it is preferable to diffuse ozone as fine bubbles having a bubble diameter of about 1 mm in order to enhance the dissolution efficiency of ozone.
It is preferable to provide an air diffusing means for diffusing such fine air bubbles. Further, it is preferable to set the water depth and the residence time of ozone so that the ozone dissolution efficiency of about 95% can be achieved, and the residence time (HR
T) 10 to 15 minutes, and particularly preferably 5 minutes at a water depth of about 15 minutes for HRT. The ozone concentration of the ozone-dissolved water obtained in the ozone-dissolving tower 3 is preferably about 2.0 to 5.0 mg / L.

The ozone-dissolved water in the ozone-dissolving tower 3 is connected to the pipe 12
Is sent to the deodorizing tower 4 and is sprayed with water from an air diffuser 5 provided in the upper part of the tower. The undissolved ozone in the ozone dissolution tower 3 is taken out from the pipe 13 and sent to the deodorization tower 4 together with the odor to be used for decomposing the odorous components.

A catalyst packed layer 6 is formed in the deodorization tower 4, and the ozone dissolved water sprinkled from the sprinkling pipe 5 and the odor introduced from the pipe 14 from the lower part of the tower are the catalyst packed layer 6. Odor components are efficiently decomposed by the wet catalytic ozone oxidation in contact with gas-liquid countercurrent.

As catalysts to be filled in the deodorization tower 4, iron, manganese, cobalt, nickel, titanium, copper, silver, platinum,
A metal oxide such as palladium supported on a carrier such as zeolite, alumina or activated carbon at a ratio of 5 to 10% by weight can be used. The size of the catalyst is 5
About 10 mm is suitable. The shape of the catalyst is not particularly limited, and various shapes such as a honeycomb shape, a pellet shape, a column shape, a cylinder shape, and a plate shape can be adopted.

The amount of catalyst packed in the deodorization tower 4 is set so that the odor is SV.
When aeration is carried out at 1000 to 2000 hr ⁻¹ , the filling amount is set so that the decomposition efficiency of odorous components can reach 99.9% or more, and the SV of odor is 1000 to 2000 hr ⁻ depending on the concentration of odorous components. If it is adjusted within the range of ¹ , it is preferable to always obtain a decomposition efficiency of 99.9% or more.

The exhaust gas deodorized by the deodorizing tower 4 is discharged by the fan 7 through the pipe 15, the residual ozone is decomposed by the ozone decomposing tower 8, and then released into the atmosphere through the pipe 16.

As the ozone decomposing tower 8, one having an activated carbon packed layer and a catalyst packed layer of manganese dioxide, silver suboxide or the like is preferably used.

The ozone-dissolved water sprinkled in the deodorizing tower 4 is withdrawn from the bottom of the tower by the pump 9 through the pipe 17 and returned to the ozone-dissolving tower 3.

By circulating and using the ozone-dissolved water in this way, the decomposition products of the sulfur-based odorous components dissolved in the water are increased and the pH is lowered, so that the ozone-dissolved water is appropriately discharged out of the system. At the same time, water is replenished from the pipe 18 to control the pH of the ozone-dissolved water to be substantially constant.

[0021]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples below.

Example 1 As an odor component, H ₂ S: 5 ppm, (CH ₃ ) ₂ S: 1
ppm, CH ₃ SH: 2 ppm, (CH ₃ ) ₂ S ₂ : 0.5
An odor of 0.15 m ³ / min containing ppm was deodorized by the deodorizing device shown in FIG.

The specifications and processing conditions of each part are as follows.

[0024] [Ozone generator]         Ozone generation rate: 0.1kg-O_Three/ Hr [Ozone dissolution tower (scattering cylinder)]         Water depth: 5m         Ozone retention time (HRT): 15 min         Ozone-dissolved water Ozone concentration: 5.0 mg / L [Deodorization tower]         Catalyst type: Zeolite Co _ThreeO_Four0.05 g-Co _ThreeO_Four/ G-                     Carried in the proportion of carrier (in pellet form, size is approx.                     10 mm)         Catalyst filling amount: 4.5L         Catalyst filling height: 2m         Odor SV: 2000hr^-1         Sprinkling amount of ozone-dissolved water: 150 L / hr [Ozone decomposition / (catalyst) tower]             Catalyst type: Manganese catalyst When the odorous component concentration of the obtained treated gas was examined, it was found that
It is sure that these are also removed with a high removal rate of 99.9%.
It has been certified. The ozone dissolution efficiency in the ozone dissolution tower is 9
It is very high at 5%, and the ozone usage rate is 99% or more.
Yes, almost all of the generated ozone is effectively used for the deodorization reaction.
It was confirmed that

Comparative Example 1 An example except that the deodorization tower in Example 1 was filled with a commercially available plastic filler (shape and size are almost the same as those of the catalyst used in Example 1) instead of being filled with the catalyst. When the deodorizing process was performed in the same manner as in No. 1, the removal rate of each odorous component was as low as about 95 to 99%, and the usage rate of ozone was 90%.

In this comparative example, in order to make the odorous component removal rate equal to that in Example 1, the odor SV is 1000.
It had to be lowered to hr ^-1 . Even in this case, no improvement in the usage rate of ozone was observed.

[0027]

As described above in detail, according to the deodorizing apparatus of the present invention, the efficiency of ozone utilization and the efficiency of oxidative decomposition of odorous components by ozone can be enhanced, and extremely efficient deodorization can be performed.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a deodorizing device of the present invention.

[Explanation of symbols]

1 oxygen generator 2 Ozone generator 3 ozone dissolution tower 4 deodorization tower 6 catalyst packed bed 8 ozone decomposition tower

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-51-17174 (JP, A) JP-A-58-89931 (JP, A) JP-A-54-119371 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B01D 53/34

Claims (4)

(57) [Claims] 1. A means for producing ozone-dissolved water, a deodorizing tower filled with a catalyst, means for upwardly flowing odor into the deodorizing tower, and means for sprinkling ozone-dissolved water from the upper part of the deodorizing tower. And a means for decomposing residual ozone in the exhaust gas discharged from the deodorization tower. 2. The ozone-dissolved water product according to claim 1,
Manufacturing means is ozone dissolution with ozone concentration of 2.0-5.0 mg / L
Deodorizing device characterized by being for obtaining water dissolution
Place 3. The deodorizing tower according to claim 1 or 2,
Circulating means for recycling hydrated ozone-dissolved water
And control so that the pH of the ozone-dissolved water becomes almost constant
Deodorizing device, characterized by comprising:
Place 4. The odor according to any one of claims 1 to 3.
The catalyst contains 5 to 10% by weight of metal oxide as a carrier.
A deodorizing device, characterized in that it is a catalyst supported in proportion.