JP2001129341A - Solvent mist collecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solvent mist collecting apparatus highly reducing the concentration of solvent mist discharged to the atmosphere. SOLUTION: A constitution body comprising a solvent mist absorbing liquid bed forming piercing reticulated structure layer/contact liquid layer or piercing reticulated structure layer/contact liquid layer/upper layer is formed and solvent mist is passed through one or several constitutional bodies to be recovered and caught effectively and efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cleaning solvent mist generated from a general-purpose part / material cleaning apparatus, a mixed solvent mist discharged from a clean room of a solvent used in a semiconductor or liquid crystal manufacturing line, and various chemical manufacturing. The present invention relates to a novel solvent mist recovery apparatus for recovering a solvent discharged from a plant and reducing the solvent mist discharged to the atmosphere as much as possible to contribute to global environmental conservation.

[0002]

2. Description of the Related Art Volatile solvent mist such as a cleaning agent, when released into the atmosphere, causes deterioration of the global environment. Therefore, various methods have been industrialized for collecting and capturing the mist. Was. Typical techniques include cooling and collecting the solvent mist as a condensed liquid at normal pressure or under pressure, collecting it with a mist adsorbent such as activated carbon, and a liquid that dissolves the mist well. Absorption and recovery methods for absorption have been put to practical use.

[0003] These industrial technologies each have advantages and disadvantages. That is, in the cooling recovery method, while a continuous recovery operation can be performed, in the case of a flammable solvent mist, there is a risk of ignition, so that the treatment is often performed in an inert atmosphere such as a nitrogen stream. Further, in the activated carbon adsorption method, although a large amount of solvent mist can be treated, it is necessary to adsorb the activated carbon and then regenerate the activated carbon by desorption, so that a batch treatment is inevitable. Certainly, improvements have been made to perform this adsorption and desorption continuously, called the fluidized bed method.However, since desorption of activated carbon that has adsorbed mist is performed in a continuous next step, it is not to avoid a batch-like treatment mode. Absent. In addition, since the desorption step is performed by passing steam at a high temperature and a high pressure, there is a drawback that not only the solvent is deteriorated but the recovery efficiency is reduced depending on the properties of the solvent, but also a solvent of poor purity is recovered. Furthermore, in the absorption recovery method,
It is the simplest method among a series of recovery techniques, but the current situation is that the concentration of exhausted gas into the atmosphere cannot be reduced so much with the spontaneous evaporation of the solvent mist in the absorbing liquid.

[0004] As described above, various industrialization techniques have been attempted to reduce the concentration of exhausted gas into the atmosphere by collecting and capturing a solvent mist. However, the practical value of a practically used processing apparatus is at most 100 ppm as an exhausted concentration. The lower limit is the actual situation. In addition, realizing such high performance not only occupies a large installation area, but also requires a large-sized apparatus, and an initial investment of 6 to tens of millions of yen, and in some cases, hundreds of millions of yen. Have been forced to Therefore, companies that have introduced such a processing apparatus are semiconductors, VLSIs, liquid crystals, liquid crystal devices, and semiconductors that require a clean room level to maintain a large and well-funded working environment.
At present, it is a limited production site for films, gravure printing, etc., and there is a deeper view of capital investment unavoidable in production than in preserving the global environment.

[0005] In manufacturing sites involving the generation of solvent mist, especially small and medium-sized manufacturers with poor financial resources, large amounts of air are exhausted when exhausting the solvent mist to the atmosphere in order to cope with increasingly strict regulations on air pollution and the environment. In many cases, a method of mixing is used to reduce the apparent exhaust gas concentration below the reference value.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to efficiently and effectively treat volatile solvent mist generated from a clean room, a cleaning tank, and the like. As a result, it is an object of the present invention to provide a novel processing apparatus that can easily introduce the solvent mist to even small and medium-sized manufacturers by realizing the concentration of the solvent mist in the atmosphere at the level of 10 ppm.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that a specific penetrating mesh structure layer (microporous filter) and a liquid layer which is in contact therewith and does not pass through the structure The present invention has been completed by finding that the constituent layer composed of the second liquid layer incompatible with the liquid and / or the liquid effectively and efficiently captures the solvent mist.

That is, according to the present invention, the network pore size of the penetrating network structure layer is 50 to 0.05 μm, more preferably 2 to 0.05 μm.
One of the features is that the thickness is 0 to 0.1 μm.
Here, if the pore diameter is larger than 50 μm, it is not possible to stably hold the liquid in contact with the pore diameter, or it is easy to easily pass through the pore diameter, and if it is smaller than 0.05 μm,
This is because the passing load resistance of the solvent mist airflow becomes too large and the industrial utility value is impaired.

The surface of the above-described penetrating network structure layer has a surface that maintains a large surface tension with the liquid in order to stably hold the liquid in contact therewith without passing the liquid. Is desirable. for that purpose,
The surface of the penetrating network structure layer is preferably water-repellent or oil-repellent, and examples thereof include a fluoropolymer surface such as polyethylene tetrafluoride and a silicone-modified fluoropolymer surface. In this case, the penetrating network structure layer itself may be made of such a polymer material, or may be surface-treated on a cloth-like microfilter made of metal, ceramics, organic fiber, or the like. Furthermore, when the stiffness of such a penetrating network structure layer is weak, a stiff filter-like reinforcing layer may be laminated.

In such a penetrating network structure layer and a liquid layer in contact therewith, a liquid having a surface tension of not less than 20 dyne / cm, more preferably not less than 35 dyne / cm, is used. It is desirable. In this case, the surface tension of the liquid is 20 dy
This is because it has been confirmed by an experiment that when the diameter is smaller than less than ne / cm, it is easy to pass through the penetrating network structure layer. A typical example of such a liquid is water,
The present invention is not limited to this, and an alkylene glycol-based compound is also effective.

In the above-described system of the penetrating network structure layer and the liquid layer in contact therewith, if the liquid layer has the ability to absorb the solvent mist, the two-layer structure may be used, but the ability is sufficient. Otherwise, a three-layer structure in which a second liquid that is incompatible with the liquid and can absorb the solvent mist is formed in contact with the upper layer is used. In this case, it has been experimentally confirmed that the use of a plurality of layers in an arbitrary combination thereof makes the collection and capture of the solvent mist more effective. Further, in these cases, as a method for effectively performing the collection and capture efficiency of the solvent mist, a method in which the mist is gasified under reduced pressure or pressure and passed through the structure is effective.

[0012]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a basic mechanism of solvent mist recovery according to the present invention. FIG. 1 shows an example in which a penetrating network structure layer / a liquid layer in contact therewith is used in three layers. However, the number of superimposed stages is not limited to three, but may be arbitrarily selected from one to several stages depending on the nature and amount of the solvent mist to be collected and captured. In the multi-stage system, the selective permeable membrane (penetrating network structure layer) and the absorbing solvent (contact liquid) in each constituent may be the same or different combinations. Although FIG. 1 shows two layers of the selective permeable membrane / absorbing solvent as the constituent body, three layers of the permeable membrane / contact liquid / absorbing solvent may be used.

FIGS. 2 and 3 show another example of a solvent mist recovery mechanism according to the present invention. That is,
FIG. 2 shows a mechanism for collecting a large amount of solvent mist, and FIG. 3 shows a mechanism for gasifying the solvent mist and sending the gas to the structure.

[0014]

Example 1 In the basic structure of the solvent mist recovery according to the present invention shown in FIG. 1, a micro-tex #NFT 1033-NO1 manufactured by Nitto Denko Corporation was used as a penetrating network structure.
(Polypropylene net, surface treated with polyethylene tetrafluoride, thickness 190 μm, average pore diameter 3.0 μm), water (water layer thickness 25 mm) as a liquid that comes into contact therewith, and Nikko Petrochemical ( NS Clean # 220 (n-dodegan, layer thickness 25 mm) manufactured by Co., Ltd. was placed, and 1.1.1 trichloroethane (boiling point 74 ° C.) vaporized at the boiling point was passed therethrough. As a result, when the concentration of the solvent mist discharged into the atmosphere was measured using a Kitagawa type detector tube, it was 37 pp when the above-mentioned structure was one stage.
m, 14 ppm in the second stage and 9 ppm in the third stage.
As a comparative example, NS Clean # 220 layer (100 m thick)
m) alone, 1.1.1 trichloroethane was passed through and absorbed, and the atmospheric exhaust concentration was 200 to 300 ppm.

[0015]

Example 2 In Example 1, the solvent mist was
Absol VG (Albemarl Co., Ltd., 1-bromopropane, boiling point 71 ° C.) and Zeorola H (Nippon Zeon Co., Ltd., fluorine-based compound, boiling point 83 ° C.) were also subjected to boiling point vapor solvent mist absorption experiments, and 1 was obtained.

[Table 1] The solvent mist in Examples 1 and 2 is insoluble in water and has a higher specific gravity than water. In these, however, these solvent mists are not absorbed by NS Clean # 220 but are mixed with microtex. The solvent mist that reached the water interface was separated and collected downward as a condensed liquid.

[0016]

Example 3 In Example 1, methyl isopropyl ketone (boiling point: 94 ° C.) and cyclopentanone (boiling point: 131 ° C.) were used as solvent mist insoluble in water and smaller in specific gravity than water.
C), the same experiment was performed, and the results in Table 2 were obtained. The solvent mist in this embodiment is NS Clean # 220
And was effectively collected and captured. In the above Examples 1-3, as the mesh penetrating structure, another microtex (water-repellent or oil-repellent treated type) having a pore diameter of 0.1 to 10 ppm, a stainless steel or ceramic having a pore diameter of 50 to 10 μm was used. Microfilters treated with a fluorine compound or a silicone-modified fluorine compound, a polyalkylene glycol compound as a liquid in contact with the network penetrating structure, and NS Clean 10 as an absorption solvent
0 (manufactured by Nippon Mining & Chemicals Co., Ltd., n-decane), Technocare FR
Experiments were conducted with various combinations of W-1 (manufactured by GE Toshiba Silicone Co., Ltd., low molecular weight porinrosaquine), normal methylpyrrolidone, and 1.3-dimethyl-2-imidazolindine. Good results were obtained.

[0017]

According to the present invention, even when the solvent mist has a high concentration at the boiling point, the solvent mist can realize an extremely low atmospheric exhaust concentration which cannot be achieved by the conventional technology.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a basic configuration for solvent mist recovery.

FIG. 2 is an example of a mechanism for increasing the capacity of solvent mist recovery, and shows a cross-sectional view (top) and a view seen from above (bottom).

FIG. 3 is a drawing of a mechanism for generating an air flow in a solvent mist.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Selective permeable membrane (penetrating network structure) 2 ... Absorption solvent, or contact liquid / absorption solvent two-layer structure 3 ... Solvent mist 4 ... Solvent mist injection 5 ... Solvent mist collection・ Capture vessel 6 ・ ・ ・ Solvent mist passage duct 7 ・ ・ ・ Recovered solvent 8 ・ ・ ・ Valve 9 ・ ・ ・ Recovered liquid 10 ・ ・ ・ Solvent mist gasification mechanism 11 ・ ・ ・ Indirect heating by boiler etc. 12 ・ ・ ・Pressure pump 13 ・ ・ ・ Piston 14 ・ ・ ・ Exhaust of solvent mist

Claims (8)

[Claims] The present invention relates to a solid / liquid composite layer formed from a penetrating network structure layer and a liquid layer in contact therewith and not passing through the network, wherein a solvent mist to be recovered is guided to a solid network layer and then to a liquid layer. Characteristic solvent mist collection device. 2. The network according to claim 1, wherein the network pore size of the penetrating network structure layer is 50 to 0.05 μm, more preferably 20 to 0.05 μm.
0.1 μm. 3. The penetrating network structure according to claim 2, wherein the pores of the penetrating network layer are formed from a surface that does not allow the contacting liquid to pass through. 4. The solvent according to claim 1, wherein the liquid in contact with the penetrating network structure layer has a surface tension not less than 20 dyne / cm, more preferably not less than 35 dyne / cm. Mist collection device. 5. The liquid according to claim 1, wherein the liquid in liquid contact is:
A solvent mist collection device having a characteristic of absorbing and dissolving a solvent mist. 6. The solid / liquid composite layer according to claim 1, wherein the liquid in contact with the penetrating network structure layer is a solid / liquid composite layer having almost no ability to absorb solvent mist, and is incompatible with the contact liquid. A solid / contact liquid / second liquid is formed by providing a second liquid layer having a lower specific gravity than the liquid and having an ability to absorb solvent mist as an upper layer of the contact liquid. Solvent mist recovery device. 7. The method according to claim 1, wherein the solvent mist to be recovered and captured is introduced into the penetrating network structure layer by gasification by decompression or pressurization, and a part of the mist containing air and the like is captured. A solvent mist collection device for discharging solvent mist that cannot be removed through a liquid layer. 8. The method according to claim 1, wherein the solid / contact liquid or the solid / contact liquid / second liquid is used.
A solvent mist recovery apparatus characterized in that any combination of these composite layers is formed in multiple stages without contacting each other, with the composite layers made of the liquids being independent mechanisms.