JPH05317637A - Device for purifying gas - Google Patents

Abstract

PURPOSE: To effectively remove an undesirable gas component such as odorous gas or harmful gas such as trimethylamine in a gas and to remove particles in a gas phase in the gas cleaning method. CONSTITUTION: In the cleaning device, a filter 4 produced from a substance which adsorbs a harmful component in a gas phase is held between electrodes 2, 3, and an electric field is applied on the filter. The gas is passed through the filter to remove the harmful component in the gas phase.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas purifying apparatus for removing harmful components in a gas phase, and in particular to a novel gas which has an excellent effect in removing gaseous harmful substances in air. Purification device

[0002]

2. Description of the Related Art Conventionally, in the purification of gas, for example, the purification of air, various methods have been known as the purification means, usually a dry method, one of the typical methods of which is a filtration method. In the method, particles are mainly removed by passing air through a filter.
For example, filter paper, filter cloth, glass filter and the like are used. In addition, since this filtration method cannot remove the gas component in the air, if you want to remove the harmful gas component in the air, a method using an adsorbent that can adsorb and remove such gas component is also a typical purification method. It is used as one of the methods, and activated carbon, an ion exchanger, etc. are used as the adsorbent. In the method of using the adsorbent, air is usually passed through the adsorbent, so that the adsorbing action and the filtering action are usually combined.

Further, in the above-mentioned method of filtering air through a filter, only large particles among particles existing in the air can be removed, and fine particles cannot be removed well. The electrostatic precipitating method is known as one of the typical purification methods as a method for sufficiently removing various particles. In this method, a high voltage is applied to at least one pair of electrodes to form an electric field, and particles in the air are charged and attached to the electrodes to be removed.

This electrostatic precipitator has a high efficiency in removing particles in the air, but since a high voltage is applied to form an electric field, it causes discharge or ionizes gas components. Therefore, various improvements have been made. As one of them, in WO91 / 05611, at least a pair of electrodes provided so as to be separated from each other is constituted by a wire net, a screen, etc., and a different potential is applied to each electrode, and practical ionization of particles is performed. An apparatus is disclosed for filtering particles from air, which is provided with a sufficiently low potential to be avoided and air is passed through these electrodes so that an electric field traps the particles. In this filtration device, air passes through the electrode groups arranged concentrically or the like, or flows in parallel to these electrodes to remove particles. Removal is also provided by a provided, for example, corrugated retention material, which is a filter paper or mesh, which retains the low-evaporative liquid and which has the ability to trap particles in the electric field. It is increasing.

[0005]

However, in the method of filtering the gas with a filter, only particles in the gas can be removed, and in the method of removing the gas component with an adsorbing substance such as activated carbon or an ion exchanger, In order to remove them, it is necessary that they are sufficiently in contact with each other and interact with each other. In this case, some contact time is required,
In some cases, this contact time may take a long time, and due to this, there are some that cannot be put to practical use.

Further, although the above-mentioned filtering device of WO91 / 05611 can also remove fumes, for example, fine particles in the smoke of cigarettes, this device cannot remove gas components, especially harmful gas components or The odor component cannot be removed. Of these, particularly the odorous components are extremely difficult to remove because their contents in the gas are extremely small.

In the purification of gas, only particles or only harmful gas components are contained in the gas, and it is rare to remove only them. They are contained together, and all of them are sufficiently removed. Is desirable
In particular, it is desirable to sufficiently remove odorous components. On the other hand, it is required in each industry to develop means capable of sufficiently removing odorous components in the air. For example, in transporting fresh fish by a frozen container car or a cold storage car, the fish odor attached to the inner wall of the container Has become an important issue. Fish odor has amines, especially trimethylamine as a main component, but has a particularly low threshold value (1 ppb) and odor is very disliked.

The present invention is intended to provide a purifying device capable of sufficiently removing a gas component having a very small content in the gas in purifying the gas. Further, the present invention is intended to provide a purifying device capable of sufficiently removing gas components having a very small content together with particles in the gas in purifying gas.

[0009]

[Means for Solving the Problems] The inventors of the present invention have conducted various researches to solve the above-mentioned problems.
In the O91 / 05611 filtering device, when air passes through the space between the electrodes or through the electrode and the holding material, the action of the electric field, the filtering of the holding material, and the trapping of the holding material by the low-evaporation liquid It has been found that only particles can be removed because they only receive the gas, but when an adsorbent material, especially an ion exchange fiber, is used as a filter, gas components can also be removed very quickly. The present invention is based on this new finding.

That is, the present invention has solved the above problems by the following means. (1) A gas characterized by removing harmful components in the gas phase by sandwiching a filter made of a substance that adsorbs the harmful components in the gas phase between electrodes and applying an electric field, and passing gas through this Purification device. (2) The gas purifying apparatus as described in (1) above, wherein ion exchange fibers are used as the substance that adsorbs the harmful components in the gas phase.

In the present invention, a filter made of a material that adsorbs harmful components in the gas phase is used as the filter. Examples of the adsorbed substance include ion exchange fibers, porous ion exchangers, activated carbon, etc., and ion exchange fibers are particularly preferable. Activated carbon fibers can be used as the activated carbon. As the filter used here, it is not preferable that the filter material is made of an adsorbed substance, that is, the entire filter is made of an adsorbed substance and the adsorbed substance particles are held between the fibers of the filter. .. As the harmful components in the gas phase here, in addition to the odorous components described above, hydrogen sulfide,
Including sulfurous acid gas.

In the present invention, the filter is provided between both electrodes to which an electric field is applied, so that all the gas is passed through the filter. In this point also, a part of air is present between the electrodes and the electrode surface. WO91 / 05611 in parallel flow format
It is different from the filtration device. The electrode used for this may be a flat plate-like one, but a breathable one such as a mesh, a perforated plate or a mesh is preferable in order to reduce the air resistance to the filter. The material of the electrodes is usually a metal, but materials known in the electrostatic precipitating technique can be used as they are. The distance between the electrodes, the voltage applied to the electrodes, and the like are appropriately determined depending on the type of gas to be treated and the amount of treatment. The voltage applied to the electrodes is preferably such that ionization of the gas component does not occur. For example, 20
00-10,000V, preferably 3000-9000
It is V.

The present invention is extremely effective for removing fishy odor in the above-mentioned refrigerated container trucks or cold storage trucks for transporting fresh fish, and food storage and large-sized food storages that are extremely reluctant to smell. Also used in refrigerators. It is useful when used in hospitals or other places where a special odor is likely to be present, such as a biological test building. In addition, it can be used to treat waste gas from factories, where the emission of malodorous gas is a problem.

Next, the gas purifying apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 schematically shows a principle apparatus having the simplest structure. Is provided with a pair of electrodes 2 and 3 on both sides of a filter 5 made of a substance that adsorbs harmful components in the gas phase,
A DC power supply 4 is connected to these electrodes, a high potential is applied so that one electrode 2 becomes a positive electrode and the other electrode 3 becomes a negative electrode, and an electric field is applied across the filter 5. A gas containing trimethylamine, for example, enters through the inlet 7, is processed through the filter 5, the trimethylamine is removed, and exits through the outlet 8.

[0015]

In the present invention, the gas component is extremely well removed together with the removal of particles by the electric field by passing the gas through a place where an electric field is applied by sandwiching a filter made of a substance that adsorbs the gas component with an electrode. .. And, the removal of the gas component is better than the case where the gas is simply passed through a filter made of a material that adsorbs the gas component. Although the technical reason for this is unknown, it is possible that the gas component is changed to a state in which it is easily adsorbed to the adsorbent by the electric field, or the adsorbed substance is changed to a state in which the component is easily adsorbed by the electric field. Be done. In any case, in the present invention, by passing through the filter, a very small amount of gas components such as odorous components such as trimethylamine can be removed very well.

[0016]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to this embodiment. Example 1 A gas purification apparatus having the structure shown in FIG. 1 was constructed, air having a tritotylamine concentration of 50 ppb was introduced, and a ventilation rate was changed to perform a purification treatment test. The material of the filter was changed, and whether or not the electric field was applied was changed. The potential applied to the electrodes was 6000V. As the ion exchange fiber, a sulfonic acid type polyolefin fiber was used.
As a comparative conventional method, filtration was performed using a filter made of glass fiber, activated carbon fiber, polyethylene / polypropylene non-woven fabric, and ion exchange fiber.
Further, a non-woven polyethylene / polypropylene filter was used, and a case where an electric field was applied was also performed for comparison.
The constitution and thickness of the filter used are shown in Table 2.

The concentration of trimethylamine in the processing gas discharged from this gas purification apparatus was measured. The measurement results are shown in Table 1. In addition, the size of particles retained by each filter was measured. The measurement results are shown in Table 2.

[0018]

[Table 1]

[0019]

[Table 2]

As can be seen from Table 1, the gas treated by the apparatus of the present invention contained very little odorous component, trimethylamine, and had almost no odor. Even when a filter made of the same ion exchange fiber was used, the effect of removing trimethylamine was not so different from that of the filter made of activated carbon fiber when no electric field was applied. Moreover, according to Table 2, the particle size of the particles retained by the filter hardly changes depending on the material or the thickness of the filter.

[0021]

EFFECTS OF THE INVENTION According to the present invention, a filter made of a substance that adsorbs harmful components is sandwiched between electrodes and gas is passed through a place where an electric field is applied. Very well removed. Then, the harmful gas components are removed more effectively than when the gas is simply passed through a filter made of a material that adsorbs the harmful components. In particular, since trimethylamine, which is a fish odor component, can be removed very well, container cars and cold storage cars used for transporting or storing fresh fish,
It is effectively used in refrigerators.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a gas purifying device of the present invention having a simple structure.

[Explanation of symbols]

 1 Gas Purifier 2 Electrode 3 Electrode 4 DC Supply Power 5 Filter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yu Takai 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Inside the EBARA Research Institute, Inc. (72) Inventor Atsushi Kobayashi 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa No. 1 Inside EBARA Research Institute, Inc. (72) Inventor Takeshi Yoshioka 4-2-1 Honfujisawa, Fujisawa City, Kanagawa Inside EBARA Research Institute, Inc.

Claims (2)

[Claims] 1. A harmful substance in a gas phase is removed by sandwiching a filter made of a substance that adsorbs a harmful component in the gas phase between electrodes and applying an electric field, and passing a gas therethrough. Gas purification device. 2. The gas purifying apparatus according to claim 1, wherein an ion exchange fiber is used as the substance that adsorbs the harmful component in the gas phase.