JPS6354959A - Method and apparatus for removing particulate material from gas flow - Google Patents

Abstract

PURPOSE:To remove charged particles by passing through a gas flow containing charged particles through an ion-exchange filter consisting of a vacant space containing polymer body supporting ion-exchange matter by a graft polymerization method. CONSTITUTION:The particles in the air 20 which is introduced by a fan 8 and is filtrated by a prefilter 23 are efficiently charged by the photoelectrons emitted from a photoelectron emitting material 21 by ultraviolet rays irradiated by a ultraviolet ray lamp 22. And, the charged particles are efficiently caught by the fibrous ion-exchange filter 10, and a clean air 24 is obtained. The fibrous ion-exchange filter 10 consists of a vacant space containing polymer body supporting ion-exchange matter by the graft polymerization method. Thus, the charged particles are efficiently caught without rescattering of the caught particles to enable stable operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method and an apparatus for removing charged particles from a gas stream containing them, in particular: (i) the electronic industry, the pharmaceutical industry, the food industry, the agriculture and forestry industry; Clean rooms, clean booths, clean tunnels in medical care, precision machinery industry, etc.
Methods and devices for removing charged particles from gas flows such as air, nitrogen, oxygen, etc. in clean pliers, safety cabinets, sterile rooms, pass boxes, sterile air curtains, clean tubes, etc., such as flue gas and automobile exhaust gas. The present invention relates to a method and an apparatus for removing charged particulates from particulate-containing gas discharged from various industries.

[Conventional technology and its problems]

Conventionally, for example, indoor air purification methods and devices can be roughly divided into fi+ mechanical filtration methods (e.g. HEP & filter)
(2) A filtration method using a high-voltage charged and conductive filter that electrostatically collects fine particles (for example, MKS
A filter), but each of these methods had the following drawbacks.

In other words, in the mechanical filtration method, it is necessary to use a fine-mesh filter in order to improve the air cleanliness (class), but in this case the pressure loss is high, and the increase in pressure loss due to clogging is also significant. Not only is it difficult to maintain, manage, or replace the filter, but the life of the filter is also short.
When replacing the filter, it is necessary to stop the work during that time, and it takes a long time to recover, which has the disadvantage of poor production efficiency.

Additionally, in order to improve the cleanliness of the air, the number of times of ventilation (the number of times air is circulated by a fan) has been increased, but this has the disadvantage of high power costs.

In addition, since the conventional filter method is only intended to remove particulates, it can be used for industrial IJ-rooms, but filters almost always have pinholes, which prevents contaminated air from entering the room. There was a limit to its use in biological clean rooms due to leakage.

Furthermore, in the method of electrostatically collecting particles, a high voltage of 15 to 70 kV is required in the pre-charging section, which increases the size of the device and poses problems in terms of safety and maintenance. there were.

In order to solve these problems, the present inventor first proposed a method of purifying the air by charging fine particles in gas by irradiating them with ultraviolet rays or radiation and then collecting them (patent application). No. 18725, 1982, patent application No. 8, 1983
No. 5996), charged particles were sometimes not collected sufficiently.

For example, when using a dust collection plate (dust collection electrode) as a method for collecting charged particulate matter, ultrafine particles such as 0.05μ
Not only was the efficiency of collecting fine particles of less than m2 insufficient, but there were also cases where the collected fine particles were scattered during unsteady operation.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for efficiently collecting charged particles, particularly charged fine particles, in a gas flow.

[Structure of the invention]

The present invention passes a gas flow containing charged fine particles through an ion exchange filter in which an ion exchanger is supported by graft polymerization on a porous polymer support, and further irradiates the gas flow containing fine particles with ultraviolet rays or radiation. By pre-charging the particles, the particles are passed over the ion exchange filter, and then charged! A method for removing charged particulates from a gas flow by trapping the particulates in the filter, and a method for pre-charging a gas flow path from a gas flow inlet to a gas flow outlet containing particulates by at least an ultraviolet ray or radiation irradiation part. This is a device for removing charged particles from a gas flow, which is sequentially provided with an ion exchange filter in which an ion exchanger is supported by graft polymerization on a porous polymer support and a porous polymer support.

Next, an example in which an embodiment of the present invention is applied to a clean room, in which all particles in the air are charged by irradiating ultraviolet rays and then collected by a filter, will be described with reference to FIG.

In Fig. 1, 1 is a clean room, 2 is an outside air intake pipe, 5 is a pre-filter, 4 is an air outlet from the IJ-room, 5 is a fan, 6 is an air conditioner, and 7 is an air conditioner.
KPA filter, 8 is the fan section in the clean room, 9
10 is an ultraviolet irradiation unit, 10 is an ion exchange filter in which an ion exchanger is supported on a fibrous polymer support, 11 is a clean bench, 12 is a movable shutter, and 15 is an assembly.

Inside the clean room 1, after filtering the coarse particles of the outside air introduced from the piping 2 with a pre-filter 5, the air taken out from the air outlet 4 of the clean room 1 is sent to the air conditioner 6 via the fan 5 to adjust the temperature. After adjusting the humidity and temperature, the air from which particulates have been removed by the HTLPk filter 7 is circulated and supplied, and the cleanliness (class) t o, o
It is maintained at about oo.

On the other hand, in the clean room 1, a fan section 8, an ultraviolet irradiation section 9, and a clean bench 11 are provided with an ion exchange filter 10 in which an ion exchanger is supported on a fibrous polymer support.
The workbench 15 inside is maintained in a sterile atmosphere of high cleanliness (class 10).

In the clean bench 11, air with a cleanliness level (class) + 0.000 in the clean room 1 is sucked in by the fan in the fan unit 8, and is irradiated with ultraviolet rays in the ultraviolet irradiation unit 9 to remove air from the air. The fine particles are charged and microorganisms such as viruses, bacteria, yeast, mold, etc. are sterilized and charged, and then the charged fine particles are removed by the filter IO.The surface on the workbench 15 is maintained at a high level of cleanliness. Note that instruments, products, etc. are taken in and out of the workbench 15 in the clean bench 11 using a movable shutter 12 provided on the clean bench 11.

The entire ultraviolet irradiation section, which is a preliminary charging section, is shown in FIG. In FIG. 2, numerals 8 and 0 have the same meanings as shown in FIG.
5 is a pre-filter,
24 indicates the flow of purified air.

The fine particles in the air 20 taken in by the filter 77 and filtered by the prefilter 25 are efficiently charged by photoelectrons emitted from the photoelectron emitting material 21 by the ultraviolet rays irradiated from the ultraviolet lamp 22. Then, the charged particles are efficiently collected by the fibrous ion exchange filter 10Vc, and clean air 24 is obtained.

The photoelectron emitting material 21 may be any material as long as it emits photoelectrons upon irradiation with radiation or ultraviolet rays, and the smaller the photoelectric work function, the more preferable it is. In terms of effectiveness and economy,
Ba, lr, Ca, Y, Gd.

La, (je, Nd, Th, Pr, Be, Zr, Fa,
Ni, Zn, Cu, Ag, Pt, Cd.

Pb, A/, C, Mg, Au, In, B1. Nb,S
l, T1. Any one of Ta, Sn, and P, or a compound or alloy thereof is preferred, and these may be used alone or in combination of two or more. As the composite material, a physical composite material such as amalgam can also be used.

Examples of compounds include oxides, ferrides, and carbides, and oxides include BaO, SrO, CaO, Y2O6°G4
203. Nd2O3, Tt+02. ZrO2, Fe2O
3, ZnO, CuO, Ag2O.

PtO, PbO, AI! 203. MgO1 engineering n203.
B10. NbO, Boo, etc. are harsh, and borides include YB6. CaB6. LaB6. CaB6゜PrB6. Z
Examples include rB2, and carbides such as ZrC and Ta.
C, TICj, HbO, etc.

In addition, alloys include brass, bronze, phosphor bronze, Ag and Mg.
(Mg is 2 to 20 wt%), O and BO (Be is 1 to 10 wt%), and Ba and AP can be used.
Alloys with e and B& with A/ are preferred. Oxides can also be obtained by heating only the metal surface in air or oxidizing it with chemicals.

As another method, it is also possible to heat the material before use and remove the entire oxide layer on the surface to obtain a stable oxide layer over a long period of time. As an example of this, an oxide thin film can be formed on the surface of an alloy of Mg and Ag in water vapor at a temperature of 500 to 400 C, and this oxide thin film is stable for a long period of time.

These materials may be used in any shape such as a plate, pleats, or net, but it is preferable to have a shape that has a large area of irradiation with ultraviolet rays and a large contact area with air. is preferred.

The type of ultraviolet light may be any type as long as the photoelectron-emitting material can emit photoelectrons upon irradiation, but it is preferable to use one that also has a bactericidal effect.

Laws can be established as appropriate depending on the field of application, content of work, purpose, economic efficiency, etc. For example, in the biological field, it is preferable to use deep ultraviolet rays together in terms of bactericidal action and efficiency.

Since the ion exchange filter 10 becomes clogged when used for a certain period of time, stable operation over a long period of time is possible by using a cartridge structure as necessary and replacing the filter by detecting pressure loss. .

As a method of charging fine particles in the air, I explained the method in line 9 without forming an electric field in the ultraviolet irradiation part.
By irradiating the photoelectron emitting material with ultraviolet rays (or radiation) in an electric field to which a relatively high voltage is applied, photoelectrons can be emitted and fine particles in the air can be charged more efficiently.

Next, the ion exchange filter will be explained in detail.

The ion exchange filter may be of any type as long as it has the function of collecting charged particles from the gas flow. Supported by graft polymerization is used, and these can be appropriately produced by well-known methods.

As the ion exchanger, an anion exchanger or a cation exchanger can be used.

Supports include polymers of aliphatic unsaturated hydrocarbons such as polyethylene, polypropylene, polybutylene, and polybutene, polymers of aromatic hydrocarbons such as polystyrene and polyα-methylstyrene, and alicyclic polymers such as polyvinylcyclohexane. Polymers of hydrocarbons, copolymers of these hydrocarbons, polytetrafluoroethylene, poly7
Polymers of fluorine-containing unsaturated hydrocarbons such as vinylidene fluoride, ethylene-ethylene tetra7ide copolymer, ethylene tetra7ide-propylene hexafluoride copolymer, and vinylidene fluoride-propylene hexafluoride copolymer or a copolymer thereof.

It is also possible to use matte, polyvinyl alcohol, polyamide, polyester, cellulose, wool, silk or mixtures thereof.

These supports are used as porous supports, and their shape may be any shape as long as they have a large contact area with the gas flow and have low resistance, such as an appropriate thin film-like cloth, preferably a net-like shape. An appropriate shape such as woven or fibrous shape is used.

The porosity of the porous support is 10 to 95X, preferably 50 to
It is 85%. The shape, thickness, and porosity of the porous support can be determined as appropriate depending on the shape of the device, the materials used, the structure, the expected effects, etc.

The ion exchanger that can be used in the present invention is not particularly limited, and various cation exchangers or anion exchangers can be used.

For example, exchangers containing cation exchange groups such as carboxyl groups, sulfonic acid groups, phosphoric acid groups, and phenolic hydroxyl groups, anionic exchangers such as primary to tertiary amino groups, quaternary ammonium groups, sulfonium groups, and phosphonium groups. Examples include exchangers containing ion exchange groups, or polymerized or condensed homogeneous or heterogeneous ion exchangers containing the above-mentioned positive and negative ion exchange groups.

Typical examples include acrylic acid, methacrylic acid, matahastyrene, halomethylstyrene, acyloxystyrene,
Styrene compounds such as hydroxystyrene, aminostyrene, vinylbenzenesulfonic acid, vinylpyridine, 2-
Polymers of monomers having cationic or anionic exchange groups such as methyl-5-vinylpyridine, 2-methyl-5vinylimidazole, acrylonitrile, or sulfuric acid, chlorosulfonic acid, sulfonic acid, or groups convertible thereto; Copolymers of these monomers with monomers having two or more double bonds, such as sivinylbenzene, trivinylbenzene, butadiene, ethylene glycol divinyl ether, ethylene glycol dimethacrylate,
Or an ion exchanger obtained by introducing cationic and/or anionic ion exchange groups as necessary into polyethylene, polyvinyl fluorocarbon ether, or polytetrafluoroethylene grafted with styrene, or converting them into ion exchange groups. There is an ion exchanger made of a copolymer of a vinyl monomer such as , tetrafluoroethylene, or chlorotrifluoroethylene and a perfluorovinyl monomer having an ion exchange group or a vine group converted into an ion exchange group.

The method for supporting the ion exchanger on the support is not particularly limited, and can be carried out by any known method.

For example, if the support is
Irradiation with ionizing radiation such as radiation, oxygen, ozone,
A method of carrying an ion exchanger by grafting a monomer after treatment with an oxidizing agent such as chlorosulfonic acid, hydrogen peroxide, benzoyl peroxide, peracetic acid, or two or more of these treatments, or a method of supporting an ion exchanger. (For example, polyethylene is fully irradiated with ionizing radiation, then reacted with an aqueous solution of acrylic acid and/or methacrylic acid to obtain a graft polymer, which is then hydroxylated).

Another method is to make the support support the ion exchanger through a polymer layer (adhesive layer) that has a high affinity for the ion exchanger. In this method, first, monomers are graft-polymerized on the support to form a complete adhesive layer with the ion exchanger.

As the monomer for forming the adhesive layer, one whose polymer has a high affinity or adhesion to the ion exchanger is used. Examples of such monomers include olefin monomers such as propylene, vinyl chloride-1
These include vinyl halide monomers, styrene derivatives, monomers with nitrile groups such as acrylonitrile, diene monomers such as butadiene, and monomers with acid ester groups such as vinyl acetate and ethyl acrylate.

These monomers are graft-polymerized onto the support by means such as irradiation with ionizing radiation and/or treatment with an oxidizing agent as described above. That is, after the support is pretreated by these means, it is impregnated with the monomer solution to be grafted and polymerized, or in the case of ultraviolet rays or radiation, the support is irradiated with the monomer solution impregnated. Also good. Next button is to support the ion exchanger on the support.

This method varies depending on the type of ion exchanger, its productivity, etc., but is carried out, for example, as follows. Either the raw material monomer mixture of the ion exchanger is impregnated into a support before polypolymerization, and the monomer mixture is poly(condensed) after impregnation, or the initial polymerization is partially poly(condensed) in advance. (shrink)
The combined product is impregnated onto a support as it is or, if necessary, dissolved in a suitable solvent, and after the impregnation, the 'M (condensation) reaction is completed.

The feature of this method is that since the support contains a graft polymer with a high affinity for the ion exchanger-forming monomer, the adhesive layer of the support will swell or dissolve due to the monomer mixture or its initial polymerization (condensation). However, impregnation is carried out sufficiently. As a result, the subsequent polymerization of the monomer mixture or its initial poly(condensation) product provides a structure in which the polymer is closely integrated with the support via the graft polymerization layer.

If the polymer impregnated into the support and polymerized does not have sufficient ion exchange groups, then cation or anion exchange groups are introduced by well-known means to obtain an ion exchange filter.

In this way, an ion exchange filter is produced, and a fibrous or woven anion exchange filter and a cation exchange filter are obtained.

The type, filling amount, and ratio of the anion exchange filter and cation exchange filter to be used can be determined as appropriate depending on the charge state, concentration, etc. of the charged particles in the gas flow.

For example, an anion exchange filter is effective for collecting negatively charged particles, and a cation exchange filter is effective for collecting positively charged particles. Further, the filling amount and its ratio may be determined as appropriate in accordance with the concentration and concentration ratio of the charged fine particles, taking into consideration the shape, structure, pressure loss, etc. of the device. For example, the particles are negatively charged due to pre-charging, and since there are naturally positively charged particles in the air, the anion exchange filter is 80 (V/V%), while the cation exchange filter is 2.
It is sufficient to use one filled with a ratio of 0 (V/T/%).

In the explanation regarding surface 9, the filter 10 downstream of the pre-charging section is
, 2' and 4 has been described, but it goes without saying that it can be similarly used for the coarse filter 25 at the inlet of the pre-charging section.

EXAMPLE A fibrous ion exchange filter manufactured by the following method was tested using the air purifier shown in FIG.

However, ultraviolet light source; mercury-xenon lamp photoelectron emitting surface; brass filling ratio; anion exchange filter 70%: cation exchange filter 50% (filter is fibrous). The generated fine particles are cigarette smoke (average particle size 0.5 ~0.4μl
11) Use 'ft, dilute with clean air as appropriate and add 10p/m.
The concentration was measured using a particle measuring device at the inlet (behind the coarse filter) and the outlet (behind the ion exchange resin membrane) by suctioning at 1 n. All results are shown in Table 1 below.

Table 1 Manufacturing method of ion exchange filter ■Anion exchange filter Two fibrous polypropylene is irradiated with 20 Mrad'i of electron beam in nitrogen, then immersed in a solution containing hydroxystyrene monomer and isogrene,
A graft polymerization reaction was performed. After the reaction, quaternary amination was performed to obtain an anion exchange filter.

(2) Cation exchange filter: Fibrous polypropylene was irradiated with an electron beam of 20 Mradk in nitrogen, and then immersed in an aqueous acrylic acid solution to perform a graft polymerization reaction. After the reaction,
All treatments were performed with a sodium hydroxide solution to obtain a cation exchange filter.

Although this embodiment shows a collection method using only an ion exchange filter, it goes without saying that the collection method using an ion exchange filter can be combined with other known collection methods.

For example, a method in which an ion exchange filter is used in the upstream of the flow path to perform rough collection, or a specific component is mainly collected, and a dust collection plate or an electrostatic filter is used in the downstream to perform complete collection. Also, conversely,
There is a method where rough collection is performed using a dust collection sheet metal in the upstream of the flow path (for example, only relatively large particles are collected completely in the upstream), and all collection is performed with high efficiency using an ion exchange filter in the downstream. be.

That is, the ion exchange filter can be used by appropriately selecting a usage method that takes advantage of its characteristics, depending on the field of application of the present system, usage, structure, shape, economic efficiency, etc. of the device.

〔Effect of the invention〕

t By using an ion exchange filter as a method for collecting charged particles, it is possible to efficiently collect charged particles in a gas flow;

■ Since there was no re-scattering of the collected particles, a steady operating state could be maintained for a long period of time.

2. Shape of the ion exchange filter By making the filter into a woven or fibrous form such as a full net, practical anion exchange filters and cation exchange filters with low resistance were obtained.

(v) By pre-charging by ultraviolet irradiation or radiation irradiation method and collecting charged particles with an ion exchange filter in the wake, the particles in the gas flow are reduced to such an extent that their outflow to the wake can be virtually ignored. A gas stream with high efficiency and ultra-high purity was obtained.

■ It can be applied to various fields and uses, and in particular, we have been able to supply effective equipment for clean rooms, where conventional methods had limitations and difficulties, especially for bio-clean rooms.

4.7 The ion exchange filter and cation exchange filter can be used appropriately or in combination depending on the charge state of particles, etc., so it is possible to provide the optimal collection method and device depending on the purpose.

5. By using an ion exchange filter in the flow path without pre-charging (by using it as a pre-filter upstream of the pre-charging section), ■ the load on the downstream pre-charging section is reduced, making maintenance management easier. This made it easier to operate continuously for a longer period of time.

As a result of the above, the application fields and uses of the ultraviolet irradiation method and the radiation irradiation method have expanded.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining an example in which the present invention is applied to a clean room, and Figure 2 is a diagram for explaining the pre-charging section in more detail. 1...Clean room, 6...HKP & filter,
8...7 part, 9...ultraviolet irradiation part, 10-kai →
... Ion exchange filter, 11 ... Clean bench, 15 ... Workbench, 21 ... Photoelectron emission material, 22.
・UV lamp,

Claims (1)

[Claims] 1. A gas flow containing charged fine particles, characterized in that the gas flow containing charged fine particles is passed through an ion exchange filter in which an ion exchanger is supported by a graft polymerization method on a porous polymer support. A method for removing charged particles from. 2. The method of claim 1, wherein the particles in the gas stream are precharged and then passed through an ion exchange filter. 3. The method according to claim 2, wherein the precharging is performed by irradiating ultraviolet light or radiation. 4. The method according to claim 3, wherein the precharging is performed using an electric field. 5. The method according to any one of claims 1 to 4, wherein the ion exchange filter is woven or fibrous. 6. Charged particulates are removed from the gas flow by sequentially providing at least a pre-charging unit consisting of an ultraviolet irradiation unit or a radiation irradiation unit and an ion exchange filter on the gas flow path from the gas flow inlet to the gas flow outlet that contains the charged particulates. A device that removes 7. The device according to claim 6, wherein an electric field is provided in the pre-charging section.