JPS58124524A - Removal of malodorous component - Google Patents

Abstract

PURPOSE:To prolong the life of a catalyst in an ozone-catalyst method and to enhance the removing effect of a malodorous component, by preliminarily removing hydrocarbons and NH3 by an activated carbon filter and a solid acid adsorbent packing tower. CONSTITUTION:A malodorous gas G is passed through an activated carbon filter 1 for removing hydrocarbons, to remove hydrocarbons and dust. In the next step, O3 is injected from an ozone generator 2 and sent to a packing tower 4 contg. a solid acid adsorpent while gas phase reaction with a malodorous components highly reactive with O3 such as H2S is promoted. The packing tower 4 is packed with an adsorbent prepared by impregnating a porous carrier such as zeolite with an inorg. acid such as phosphoric acid to adrorb and remove NH3 amoung the malodorous components. In addition, moisture from a humidity conditioner and O3 are mixed and a gaseous phase reaction of the malodorous components with O3 is promoted in a gas mixing tank 6, thus the reaction is completed in a catalytic reactor 7 and, at the same time, excessive O3 is subjected to self- decomposition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing bad odors using ozone.

One of the methods for removing bad odors generated from sewage treatment facilities and human waste treatment facilities is the so-called ozone-catalyst method (% 11957-11957), which uses the oxidizing power of ozone and a catalyst.
(See No. 1).

In order to further enhance the odor removal effect, a method (Japanese Patent Application Laid-open No. 56-150
209 (Japanese Patent Application No. 56-91490) and method 2 (Japanese Patent Application No. 56-91490) in which an activated carbon filter is provided to adsorb and remove hydrocarbons as a pretreatment.

vcFi in the exhaust gas generated from the above treatment facility, malodorous components such as ammonia, hydrogen sulfide, methyl mercaptan,
In addition to methyl sulfide and methyl disulfide, there are hydrocarbons (compounds with a carbon number of 08 to C1) that are unrelated to odor, and each of them is removed using the above application method, but due to recent environmental administration. In order to cope with the enhancement, it is necessary to further improve the malodor removal effect, and it is necessary to improve the conventional malodor removal method.

The present inventors believe that among malodorous components, hydrogen sulfide, methyl mercaptan, methyl sulfide, etc. can be removed by the ozone-catalyst method, and at the same time ammonia and hydrocarbons can be removed.
We believe that not only will the odor removal effect be improved, but the life of the catalyst will also be extended and the overall performance improved. Therefore, (1) hydrocarbons in the target gas to be treated, which cause a decrease in catalyst activity and shorten the catalyst life, are removed in front of the catalyst layer using an activated carbon filter, and (2) ammonia, which has poor reactivity with ozone, is is removed before the catalyst layer by a solid acid adsorbent layer, and 13+ hydrogen k hydride, methyl mercaptan,
Odor components such as methyl sulfide are removed by injecting ozone and using the oxidizing power of ozone and the action of a catalyst, and it is a feature of the present invention that these methods (11 to (3)) are combined into one system. .

FIG. 1 shows a flow diagram of the malodor removal apparatus according to the present invention.

Here, the raw gas G containing a bad odor passes through the activated carbon filter layer 1 for removing hydrocarbons, and then the ozonized air is sent from the ozone generator 2 through the ozonized air branch cock 3. - Moisture H sent from the gas humidifier 5 together with the ozonized air that passes through the column 4 filled with solid acid adsorbent and is sent via the ozonized air branch cock 3 together with A.
, O and enters the gas mixing tank 6. Next, the malodorous components are sent to the catalytic reactor 7, pass through L1, and are released as a gas.

When the malodorous gas induced by the exhaust fan 8 passes through the activated carbon filter layer 1 for removing hydrocarbons, it removes hydrocarbons unrelated to the malodorous components contained in the gas, such as n-hexane,
Heptane, octane, decane, etc. are adsorbed and removed.

Activated carbon filter layer 1 contains granular or crushed activated carbon (
Raw materials include palm, coal, charcoal, petroleum pitch, etc.] are filled in a thin layer (~100m1m) and packaged for easy replacement. In this activated carbon filter layer 1, 80 to 90 or more hydrocarbons consisting of 06 to CI5 are removed and do not overflow into the gas downstream.

Next, ozone is injected from an ozone generator 2 into the malodorous gas that has passed through the activated carbon filter layer 1, and among the malodorous components,
Column 4 packed with solid acid adsorbent while promoting gas phase reaction between ozone and components highly reactive with ozone such as hydrogen sulfide.
send to

In the column 4 filled with a solid acid adsorbent, 5 to 5% of inorganic acids such as phosphoric acid, sulfuric acid, and KM chloride are added to a porous carrier such as natural zeolite, synthetic zeolite, alumina, silica-alumina, or other porous carrier.
It is filled with an adsorbent impregnated with 0% by weight, and ammonia among the malodorous components is adsorbed and removed. Further, in this column 4, the ozone and components such as hydrogen sulfide are brought into effective contact, and a gas phase reaction between the two proceeds.

In the gas mixing tank, the malodorous components whose moisture content has been adjusted by the gas humidifier are mixed with ozone, and the gas phase reaction of the malodorous components is further promoted.

The catalytic reactor 7 may contain, for example, a carbonaceous material (e.g. granular,
One or more metal oxides such as vanadium, chromium, manganese, iron, cobalt, nickel, copper, silver, zinc, etc. are supported on a catalyst carrier made of crushed or powdered activated carbon, graphite, carbon fiber, etc. The catalyst is filled with a catalyst in which platinum, palladium, rhodium, ruthenium, etc. are supported as a co-catalyst along with these metal oxides as necessary.

When the gas that has passed through the gas mixing tank 6 passes through the catalytic reactor 7, the reaction between the unreacted malodorous components and ozone is completed, and at the same time, the self-decomposition of excess ozone is completed.

The method of the present invention provides the following effects.

■ Hydrocarbons contained in malodorous gas do not become malodorous components and do not pose an odor problem, but they tend to adsorb and accumulate on the catalyst surface, coating the catalyst ice surface and significantly reducing catalyst activity. (shorten catalyst life). The hydrocarbon removal filter of the present invention removes these hydrocarbons in advance before the catalyst reactor, suppresses adsorption to the catalyst surface to a minimum, prevents a decrease in catalyst activity, and shortens the catalyst life. It has the effect of

■ Since dust in the foul-smelling gas is also removed by this hydrocarbon removal filter, the catalytic reactor on the downstream side will not be contaminated by dust.

■ Since ammonia in the raw gas is adsorbed and fixed on the surface of the solid acid adsorbent, not only can the same effect as ammonia absorption and removal by washing with water or chemical cleaning be obtained, but also dust in the raw gas can be removed by this solid acid adsorbent layer. Since the dust is removed, the catalytic reactor on the downstream side is not contaminated by dust.

■ Raw gas containing malodorous components can be treated until it becomes odorless using the ozone-catalyst method without washing with water or chemicals (improving the odor removal effect), and reducing operating costs by extending the life of the catalyst. be able to.

Example 1 As a result of measuring the concentration of 08 or more components of hydrocarbons contained in the foul-smelling gas generated from the settling tank, primary settling tank, warming tank, and sludge treatment room in a sewage treatment plant, methyl hebutane, n -Octane, methyloctane, trimethylcyclohexane, n-nonane, n-decane, dimethylcyclooctane, 5-methyl/nan, n-butylcyclohexanone, and unidentified components of C11 or higher are 0,00
It was detected at a concentration of 1-1 ppm.

When this gas was passed through an ioowm thick hydrocarbon removal filter filled with granular (4 to 6 mesh) coconut shell activated carbon, the concentration of the above components in the gas downstream of the filter was 0.
．． The amount was reduced to 0,001 ppm or less, and was efficiently adsorbed on the hydrocarbon removal filter.

Example 2 100 ppm of ammonia gas was passed through a solid acid adsorbent in which 0.5.10% and 20% by weight of sulfuric acid was supported on pellets of diatomaceous earth formed to a diameter of 6 to 10 mm.

The results were as shown in Figure 2.

As is clear from Figure 2, the amount of acid impregnated is 5% by weight or more, which is effective, but it is uneconomical to use too many pieces.
It turns out that it is sufficient to add 50 points.

Example 5 In a sewage treatment facility, a ventilation fan (500Nm3
/min) and deodorized according to the flow sheet shown in FIG.

The activated carbon filter for removing hydrocarbons is filled with 1,001 pieces of granular coconut shell activated carbon (4 to 6 meshes) and is 0.4 m thick.
The gas was flowed at a flow rate of /sec.

The solid acid adsorbent for ammonia removal was filled with 150111111 pellets formed from 10-layered diatomaceous earth supported on sulfuric acid to a size of 6 to 1011 jlφ, and 0.4 Ill/S.
Gas was flowed at a flow rate of ee. Activated carbon supporting manganese oxide was used as a catalyst. Ozone was injected at 2 ppm immediately after the layer 1 of the activated carbon filter for removing hydrocarbons, and 1 ppm was injected immediately after the column 4 packed with solid acid and adhesive.

The results were as shown in the table below.

Furthermore, the effect of removing malodorous components, for example, hydrogen sulfide, after 8000 hours from the start of operation was as follows, confirming that a high deodorizing effect was maintained.

[Brief explanation of the drawing]

Figure 1 is a flow sheet showing an actual IN mode of the method of the present invention, and Figure 2 is a graph showing the relationship between the amount of acid supported and the amount of ammonia removed in the solid acid g & adhesive packed column used in the method of the present invention. It is. Sub-agents 1) Meifuku agent Ryo Hagiwara -

Claims (1)

[Claims] When removing bad odors using ozone, a single layer of activated carbon filter and a column packed with solid acid adsorbent are installed in front of the catalytic reactor to remove hydrocarbons and ammonia contained in the raw gas containing bad odor components, and then ozone is removed. - A method for removing a bad odor, characterized by removing the bad odor by a catalytic method.