JP2000237529A - Odorous component treatment apparatus and treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cost effectively and efficiently carry out the treatment of odorous components by providing an odorous component treatment apparatus having electric discharge sections to the gas to be treated which contains the odorous component to a gas flow section of the gas to be treated with a flow velocity regulating mechanism for maintaining the velocity of flow of the gas to be treated passing the electric discharge sections at a range of specific value. SOLUTION: The gas to be treated which contains the odorous components, such as hydrogen sulfide, is introduced from an introducing port 2 into the apparatus and is first distributed evenly to the plurality of electric discharge sections 3 from a distributing duct 1. Electric discharge electrodes are respectively installed in the respective electric discharge sections 3 and electrons are radiated therefrom to activate the hydrogen sulfide and oxygen in the gas to be treated. Next, the gas to be treated is introduced into a vapor phase reaction vessel 8 where the reaction of the oxygen and hydrogen sulfide in an active state is accelerated and both are oxidation cracked to water and sulfur. In succession, the gas to be treated is supplied to a catalytic vessel 6 where a slight amount of ozone generated as a by-product is adsorbed. At this time, the number of revolutions of an induction fan 4 is so regulated that the velocity of flow of the gas to be treated passing the electric discharge sections 3 is maintained in a range of 7 to 30m/s.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for treating odor components in which a discharge portion for discharging a gas to be processed is provided in a gas flow section through which a gas containing odor components such as hydrogen sulfide and methyl mercaptan passes. The present invention relates to an odor component treatment method for reducing the odor component concentration of an apparatus or a gas to be treated.

[0002]

2. Description of the Related Art Conventionally, the treatment of odor components such as hydrogen sulfide in a gas to be treated has been carried out by promoting the oxidation treatment of odor components using ozone generated by electric discharge.
When oxidizing a gas containing a large amount of odorous component using ozone, ozone is generated by discharging in an oxygen-containing gas at a location separate from the gas processing section that processes the gas to be processed. The generated ozone is mixed with the gas to be treated in the gas to be treated section to oxidize odor components. To perform such a processing method, an ozonizer configured to enable silent discharge by disposing a dielectric between a pair of electrodes is used as an odor component processing device, and an oxygen-containing gas such as dry air is applied between the pair of electrodes. To generate ozone, and the ozone is supplied to the gas to be treated containing the odor component, so that the odor component can be oxidized. In the case of oxidizing a gas containing a small amount of odor component using ozone, the gas to be processed in the gas processing section is directly discharged to directly generate ozone in the gas to be processed. Oxidation of the odor component has been performed by reacting the odor component and ozone in the gas to be treated. As an apparatus for performing such a method, a planar induction electrode is provided on the back surface of a high-purity alumina ceramic, and a linear discharge electrode is provided on the surface, and a voltage is applied between the induction electrode and the discharge electrode. Using an ozonizer that generates glow discharge on the ceramic surface,
Pass the gas to be treated containing an odor component between the induction electrode and the discharge electrode to directly generate ozone in the gas to be treated,
The odor component was configured to be oxidizable.

[0003]

However, when odor components in the air to be treated are treated with ozone, although the oxidizing ability of ozone is relatively high, the reactivity between the odor components and ozone is low, and The ozone concentration in the gas required several times the reaction equivalent of the odor component. In particular, when a relatively high-concentration odor component is treated, an amount of ozone several times that of the high-concentration odor component is required. Due to the low generation efficiency, it was huge and economic problems were sometimes pointed out.

When a gas containing a large amount of odorous component is treated, the reaction between the odorous component and the ozone in the gas to be treated is promoted to mix and agitate the gas to be treated and ozone.
It was necessary to separately provide a means for promoting the oxidative decomposition reaction such as water spray. In the case of treating a gas containing a small amount of odorous component, the amount of ozone that can be generated by electric discharge is limited to some extent. It is sometimes difficult to generate several times as much ozone, so the odor component is treated by limiting the amount of gas to be treated introduced into the treated gas treatment section and increasing the amount of ozone to the gas to be treated. There was a case. Also, when the odor component in the air to be treated is treated with ozone, a large amount of excess unreacted ozone needs to be treated because ozone is supplied at a reaction equivalent or more, and the cost of the ozone treatment agent is also required separately. was there. Therefore, an object of the present invention is to economically and efficiently treat odor components in air to be treated.

[0005]

In view of the above-mentioned problem of the treatment of the odor component in the gas to be treated using ozone, the present inventors have made intensive studies on a new treatment of the odor component in the gas to be treated. However, it has been experimentally found that by maintaining the gas to be treated containing the odor component at a specific flow rate and discharging the gas to be treated, the oxidative decomposition treatment of the odor component can be performed extremely efficiently and economically. Then, based on this finding, the present invention was completed. That is, the characteristic configuration of the odor component treatment apparatus of the present invention for achieving this object is as follows. In the gas circulation section through which the gas containing the odor component passes, a discharge section for discharging the gas to be treated is provided. Odor component processing apparatus, wherein the flow rate of the gas to be processed passing through the discharge section is 7 m / s.
Another object of the present invention is to provide a flow velocity adjusting mechanism for maintaining the flow velocity in the range of 30 m / s or less. Further, a downstream side of the discharge unit is provided with a gas phase reaction tank for performing a reaction between an odor component and oxygen, and the flow rate of the air to be treated in the gas phase reaction tank is 1 m / s or less. A configuration in which a gas phase reaction tank is formed may be employed.
In order to achieve this object, a characteristic configuration of the odor component treatment method of the present invention is to discharge a gas to be treated containing an odor component whose flow velocity is maintained in a range of 7 m / s or more and 30 m / s or less. And subjecting the odor component to an oxidative decomposition treatment.

[0006] The present inventors have used an odor component treatment apparatus provided with a discharge unit for discharging the gas to be treated in a gas flow section through which the gas to be treated containing the odor component passes. The flow rate of the gas to be processed passing through the discharge section is 7 m / s
The present invention has been completed based on the fact that, when the gas to be treated is discharged in a state where the gas is kept within the range of 30 m / s or less, the odor component in the gas to be treated is oxidized and the decomposition treatment is accelerated. I let it. In other words, I'm not going to be bound by theory,
This phenomenon is caused by the fact that when a gas to be treated containing an odor component whose flow velocity is maintained in the range of 7 m / s or more and 30 m / s or less is discharged, electrons emitted by the discharge are converted into molecules of the odor component and the gas to be treated. The energy is given to the oxygen molecules inside, the odor component molecules and the oxygen molecules are activated, and then sequentially depart from the discharge part at high speed, so that the probability of collision between the electrons and the molecules in the ground state increases, and the efficiency increases. It is considered that since active molecules are generated well, the odor components in the gas to be treated react efficiently and oxidative decomposition is promoted. Furthermore, although nitrogen exists in the odor component, the electrons given by the discharge give energy to the nitrogen molecule to activate the nitrogen molecule, and the nitrogen molecule in the active state is changed to the oxygen molecule and the odor component in the ground state. It is thought that by colliding with molecules, energy is given to oxygen molecules and odor component molecules, and these molecules are activated to promote the reaction between odor components and oxygen.

Further, the present inventor has found that there is a correlation between the generation amount of active state molecules and the flow rate in a certain range of the flow rate of the air to be processed flowing through the discharge part. That is, when the flow rate of the air to be processed is increased and the flow rate of the air to be processed flowing through the discharge portion becomes 7 m / s or more, electrons given by the discharge and oxygen molecules and odor components in the ground state in the gas to be processed There is a tendency that the efficiency of collision with the active state increases and the efficiency of generating active state molecules increases. On the other hand, if the flow rate of the air to be processed flowing through the discharge unit is 25 m / s or more, the generation efficiency of the active state molecules in the air to be processed may tend to be saturated. Despite the increase in the power supply of the odor component treatment device, the generation of active state molecules in the air to be treated, that is, the increase in the efficiency of the oxidative decomposition treatment of the odor component in the air to be treated is very small, and as a result, As a whole, the odor component treatment apparatus has not been economically decomposed. Furthermore,
If the flow velocity of the air to be processed flowing through the discharge unit is 30 m / s or more, the discharge is hindered by the air flowing at high speed, and the decomposition efficiency is rather deteriorated. These phenomena slightly change depending on the performance of the power supply difference, but in any case, the peak of the decomposition efficiency is in the range of 7 m / s to 30 m / s. Therefore, in order to economically and efficiently oxidatively decompose the odor component in the gas to be treated, the flow rate of the gas to be treated flowing through the discharge part for performing the discharge should be kept in a range of 7 m / s or more and 30 m / s or less. Is considered suitable.

[0008] In the case of clean air containing no oxidizing substance as an odor component, ozone may be generated as a by-product of the discharge, but the odor of the oxidizing substance having a certain concentration or more in the air to be treated. When a component is present, no ozone is generated, or even if it is, the amount of ozone generated is extremely small. This is because, when the odor component having a certain concentration or more is present in the air to be treated, the electrons given by the discharge activate the oxygen and the odor component in the air to be treated, and the oxygen in the active state reacts with each other. Therefore, it is considered that active oxygen and active odor components tend to react more quickly than ozone is generated.

Accordingly, it is possible to directly react oxygen and odor components in the air to be treated to oxidatively decompose the odor components in the air to be treated. Compared with the odor component treatment device using ozone, the odor component treatment device of the present invention has greatly improved the odor component decomposition efficiency with respect to the electric energy used for the entire odor component treatment device. Further, in the present invention, since the reaction of oxidative decomposition treatment proceeds by reacting with the odor component more than the oxygen in the active state changes to ozone, the amount of ozone generated as a by-product can be suppressed to a very small extent. It has become possible.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The odor component treatment apparatus of the present invention comprises a gas inlet 2 for introducing a gas to be treated into the apparatus, a gas flow section A through which a gas containing an odor component passes,
It is basically composed of a gas exhaust port 5 for discharging a gas to be processed to the outside of the apparatus. The gas circulation part A includes a plurality of discharge parts 3, a discharge gas circulation part 7, which is a gas passage to be processed in the vicinity of the discharge part 3 in the gas circulation part A, and a plurality of discharge parts 3 to be processed uniformly. A distribution duct 1 provided for distributing and introducing a gas; and a gas phase reaction tank 8 for performing a sufficient reaction between active oxygen and active odor components in the gas to be treated that has passed through the discharge unit 3. And a catalyst tank 6 for decomposing a trace amount of ozone generated by discharging the gas to be treated.
And an inducing fan 4 for forming a constant flow of the gas to be treated in the gas circulation section A.

As an example of an odor component, hydrogen sulfide (H
_The gas to be treated containing ₂ S) is introduced into the apparatus from the gas introduction port 2 to be treated, and is introduced into the distribution duct 1. The gas to be treated is evenly distributed and introduced into a plurality of discharge units 3 provided by the distribution duct 1. A plurality of discharge units 3 are provided so that even when the processing air volume of the gas to be processed is relatively large, the processing air can be discharged economically. That is, in order to process a large amount of air to be treated, it is desirable to increase the cross-sectional area of the discharge gas flow section 7. Is increased, the voltage applied to the discharge unit 3 needs to be increased in order to supply a constant electric field to the discharge unit 3, and as a result, the power supplied to the entire apparatus increases. Therefore, in order to supply a constant electric field to the discharge unit 3 without increasing the voltage applied to the discharge unit 3, a plurality of discharge units 3 are provided. When the processing air volume of the air to be processed is 4000 m ³ / h, 0.1 mx 0. It is preferable to provide four discharge units 3 each having an opening area of 25 m. As described above, since a plurality of discharge units 3 are used to perform discharge at each location and emit electrons almost uniformly to the gas to be treated, oxygen and hydrogen sulfide can be efficiently activated.

Each of the discharge sections 3 is provided with a discharge electrode, and the gas to be treated receives irradiation of electrons from the discharge electrode there. The electrons given by the discharge give energy to hydrogen sulfide and oxygen in the gas to be processed, so that hydrogen sulfide and oxygen are activated. Electrons given by the discharge give energy to nitrogen in the gas to be treated, and nitrogen molecules in an active state give energy by colliding with oxygen molecules and hydrogen sulfide in a ground state to make them active.

A gas-phase reaction tank 8 is provided downstream of the discharge unit 3, and the gas-phase reaction tank 8 has a box shape sufficiently larger than the capacity of the discharge unit 3. That is, the gas-phase reaction vessel 8 is formed such that the flow rate of the air to be treated in the gas-phase reaction vessel 8 is 1 m / s or less. The air to be processed, which has passed through the narrow high-pressure discharge section, is expanded and expanded at a stroke in the gas-phase reaction tank 8, and active molecules and odor components are mixed. Further, the structure is such that oxygen, hydrogen sulfide, nitrogen and the like in the active state in the gas to be treated hardly reach the peripheral wall of the gas-phase reaction vessel. The structure is easy to prevent energy loss due to collision with the tank peripheral wall.

When the gas to be treated is introduced into the gas phase reaction vessel 8, active oxygen, hydrogen sulfide and the like are diffused and mixed in the gas phase reaction vessel 8, and the reaction between hydrogen sulfide and oxygen is sufficiently promoted.
Oxidized by water and sulfur.

Downstream of the gas-phase reaction tank 8, a catalyst tank 6 for adsorbing a small amount of ozone generated as a by-product by discharging the gas to be treated is provided. The catalyst used in the catalyst tank 6 is formed by mixing and molding activated carbon with alumina silica gel as an adsorbent as a main component, and is decomposed into carbon dioxide and oxygen by reaction of ozone with activated carbon.

An induction fan 4 for forming a constant flow of the gas to be processed passing through the discharge section 3 is provided downstream of the catalyst tank 6. The induction fan 4 serves as a flow rate adjusting mechanism for adjusting the flow rate of the gas to be processed, and controls the flow rate of the gas to be processed passing through the discharge unit 2 by at least 7 m / s.
The fan rotation speed of the induction fan 4 can be adjusted so as to keep the range of m / s or less.

A comparison is made between the odor component treatment apparatus for treating odor components by activating the odor components according to the present invention and the efficiency of using the discharge energy for treating the odor components of the conventional odor component treatment device using ozone. did. 0.14 ppm of hydrogen sulfide, 0.23 ppm of methyl mercaptan, and 5.3 p of methyl sulfide per unit volume as odor components
When the processing air having a processing air flow of 2000 m ³ / h containing pm is processed by an odor component processing apparatus using ozone, the theoretical value of ozone required for the reaction is usually about 11.2.
ppm. When an odor component is treated by an odor component treatment device using ozone, an ozone generation capacity of 240 g / h is required if the required odor amount is five times the required theoretical ozone amount. The reason why the amount of ozone is required to be about several times the theoretical amount of ozone is that the ozone disappears due to self-decomposition and is excreted without reacting with odor components. If the ozone generating capability of the ozonizer is 40 g / KW, the power consumption at that time is 6 KW. On the other hand, when the air to be processed having the same component concentration and the same processing air volume is processed by the odor component processing device that processes the odor component by activating the odor component,
The power consumption at that time is only 1 KW. Furthermore, when the odor component is treated by the odor component treatment device using ozone, it is necessary to treat the excess ozone which is about several times the theoretical amount of ozone, and to provide a catalyst for treating the excess ozone. Not only is the cost required, but if excess ozone is discharged outside the apparatus without being treated by the catalyst, it is harmful to the human body. Therefore, the odor component treatment device that treats the odor component by activating the odor component according to the present invention has a higher use efficiency of the discharge energy than the conventional odor component treatment device using ozone. I can say.

[Other Embodiments] In the embodiment of the present invention, hydrogen sulfide is exemplified as the odor component in the gas to be treated. However, methyl mercaptan, trimethylamine, acetaldehyde and the like can also be removed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an odor component treatment device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Distribution duct 2 Air inlet to be processed 3 Discharge part 4 Induction fan 5 Exhaust port to be processed 6 Catalyst tank 7 Discharge gas circulation part 8 Gas phase reaction tank A Gas circulation part

Claims (3)

[Claims] 1. An odor component treatment apparatus comprising: a gas circulation section through which a gas to be treated containing an odor component passes; and a discharge section for discharging the gas to be treated, wherein the gas passes through the discharge section. An odor component processing apparatus having a flow rate adjusting mechanism for maintaining a flow rate of a gas to be processed in a range of 7 m / s or more and 30 m / s or less. 2. A gas-phase reactor for reacting an odor component with oxygen on the downstream side of the discharge unit, wherein the flow rate of the air to be treated in the gas-phase reactor is 1 m / s or less. The odor component treatment device according to claim 1, wherein the gas phase reaction tank is formed as described above. 3. An odor component treatment method in which the odor component is oxidized and decomposed by discharging a gas to be treated containing an odor component maintained at a flow rate of 7 m / s or more and 30 m / s or less.