JPS61414A - Separation method - Google Patents

Abstract

PURPOSE:To separate a liquid held under a phase separation state to water with high separation efficiency, by selectively permeating said liquid by using a fibrous structure having water repellency. CONSTITUTION:A fibrous structure comprising a polytetrafluoroethylene fiber or a polypropylene fiber and having water repellency is used and, by utilizing such a property that said fibrous structure has capacity for selectively permeating only a liquid held under a phase separation state to water such as mixtures of various hydrocarbon compounds such as various paraffinic hydrocarbons, for example, n-pentane or petroleum ether, said liquid is separated from water. By this method, because liquid permeability is high as compared with a film like microporous membrane, separation efficiency under atmospheric pressure is obtained at a level having no problem from a practical aspect.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for separating a liquid that is in a phase-separated state from water. More specifically, water and the liquid are separated by using a water-repellent fibrous structure and utilizing the ability of the fibrous structure to selectively permeate only a liquid that is phase-separated from water. Regarding the method.

<Prior art> Conventionally, methods for separating water from oil or organic solvents from a liquid phase in which water is mixed with liquids such as oils or organic solvents that are incompatible with water include (1) separating an oil/water mixed phase; Physical separation method using heating and distillation or centrifugal force: (2) Chemical separation method by adding a demulsifier or flocculant to the oil-water mixed phase; (3)
) An adsorption separation method using an adsorbent that selectively adsorbs only the oil phase; (4) A separation method in which these methods are selectively used in combination as appropriate. However, both methods have drawbacks such as not being able to perform complete separation and being costly.

Recently, a magnetic field separation method has also been proposed in which magnetic fine powder is supplied to an oil-water mixed phase and only the oil phase is moved using a magnetic field to separate it from the oil-water mixed phase. This method contains a large amount of oil phase, and if the oil phase exists in the form of a dispersion medium, the amount of expensive magnetic fine powder added will increase significantly, and the oil phase and magnetic fine powder It takes a lot of stirring energy to bring them into sufficient contact. Further, this magnetic fine powder has practical problems such as difficulty in reusing it even if it is recovered from the oil phase.

Furthermore, as for membrane separation technology using microporous polymer membranes, methods using filtration, dialysis, and electrodialysis are known.
In either case, the separation efficiency is poor due to low liquid permeability.
Another drawback is that the device must be larger.

<Problems to be Solved by the Invention> In view of the shortcomings of the prior art, the present inventors have developed a separation method that has high liquid permeability and high separation efficiency when separating a liquid that is in a phase-separated state from water. As a result of studying the technology, we have arrived at the present invention.

<Means for Solving the Problems> In the separation method according to the present invention, when separating a liquid that is in a phase-separated state from water, the liquid is selectively permeable using a fiber structure having four permeability. % g! 1. shall be.

"Phase-separated dust" as used in the present invention refers to dust in which an aqueous phase is dispersed in a liquid phase, or a liquid phase is dispersed in an aqueous phase, or the entire dust is divided into two parts with only one interface between them. Two-phase substances, such as those separated into layers (regardless of the form of physical dispersion,
A substance in which an aqueous phase and a liquid phase coexist. Therefore, in the present invention, not only those that are in a phase-separated state from the beginning, but also those that have been made into a phase-separated state by adding a solvent that has low solubility in water and high solubility in the liquid of interest to a homogeneous solution, and Also included is a solution in which an acid compound is dispersed, and a solvent that has low solubility in water and high solubility for the compound of interest is added to form a phase-separated state.

In the present invention, particularly suitable liquids that can be separated include those that are substantially insoluble in water and have a surface tension of 55 dyne/C1n or less. Liquids with a surface tension of 40 dyne/crn or less are safe.
Good M separation efficiency. Typical examples of these liquids are i, i
,n-A! n-tane, n-hexane, n-heptane, n
- Mixtures of various paraffinic hydrocarbons such as octane and n-decane, etc. 1) Mixtures of various hydrocarbon compounds such as ether, ligroin, gasoline, and kerosene (1) petroleum naphtha, and aromatic hydrocarbons such as benzene, toluene, and xylene. alicyclic hydrocarbon compounds represented by cyclopentane and cyclohexane, various mineral oils, vegetable oils, animal oils, various ethers, and ketones.

Examples include 7>E such as ester, alcohol, and phenol E.

The "fiber structure having water repellency" as used in the present invention refers to JI
Water pressure resistance measured by S-L-1092B method is 100 tan H20 or higher, preferably 200 tan H20 to 20
00 ttm H2O. The level of water pressure resistance is usually 10001000 depending on the conditions of separation operation.
It may be selected appropriately within the range of 0W.

The fiber structure of the present invention may be in the form of woven fabric, knitted fabric, non-woven fabric, mat, felt, or sheet. Single denier or thin fibers or fibrillated fibers may be used.
Highly densified materials such as high-density fabrics are preferably used because they can easily provide high water pressure resistance. In terms of liquid permeability, knitted fabric,
Non-woven fabrics and sheet-like fabrics are excellent even under the same water pressure resistance, and in particular, in the present invention, fibers with a single filament fineness of 1 denier or less are used as fiber structures that can easily obtain high water pressure resistance and have high liquid permeability. Examples include nonwoven fabrics and sheet-like materials made of

Examples of the fibers constituting the fiber structure of the present invention include polyethylene terephthalate, polyethylene terephthalate, etc. Fibers of polyester copolymers such as polyethylene terephthalate sophthalate, polyethylene terephthalate sepacate, polyethylene terephthalate dodecanedioate, polybutylene terephthalate, polyhexamethylene azino 4mide, polyhexamethylene sepacamide, polyhexane Methylenedecamide, polyhexamethylenehexamide, polycapramide.

Polyoctamide, polynonamide, polydecamide.

Polyamide fibers such as polydodecamide and polytetramid, polyamide/imide fibers, aromatic polyamide fibers,
Fibers of polyester ethers such as I-liparaethylene oxypenzoate, fibers of halogen-containing polymers such as polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polytetrafluoroethylene, polypropylene,
Polyolefin fibers such as polyethylene, various acrylic fibers, regenerated cellulose, acetate, cotton, linen, and silk.

Examples include wool. These fibers may be used alone or in combination.

Specific examples of water-repellent fiber structures include structures made of hydrophobic fibers such as polytetrafluoroethylene fibers, polypropylene fibers, and polyethylene fibers, or structures made of hydrophobic fibers such as polytetrafluoroethylene fibers, polypropylene fibers, and polyethylene fibers, or structures that are water-repellent by applying water-repellent treatment to the fiber structures. Examples include structures that have aqueous properties.

Water-repellent treatment of the fiber structure can be carried out using conventional methods, such as fluorocarbon resins such as acrylic acid perfluoroalcohol, silicone resins such as dimethyl silicone, -
′? A known water repellent agent such as a rough-in resin or a wax resin may be applied to the fiber structure at the time of manufacturing the yarn or by a method such as dipping, dipping, spraying, or exhaustion.

Further, if necessary, heat treatment may be performed after applying a water repellent agent.

The separation method applied to the present invention is not particularly limited, and various types of separation methods such as batch type or continuous type, vertical type, horizontal type, multi-stage type, etc.
The above method is applicable +11il function. An example of the portioning device is shown in Figure 1. In the same figure, water and (., □ 4 separation 4. A, ah, body. 1 mixture (1).

Of these, the latter liquid flows through the vertical fiber structure (2) and optionally the horizontal fiber structure (2)'f! supported on the support (3). : Selectively permeate, open valve (5) and collect.

From the standpoint of separation and filtration efficiency, it is preferable to attach the fiber structure to the filter in a bellows shape so as to increase the flow area. Furthermore, pressure filtration can also be performed at a pressure lower than the water pressure of the fibrous structure. Alternatively, it may be filtered while stirring. In particular, since the separation method of the present invention has higher liquid permeability than a film-like microporous membrane, a separation efficiency of a practically acceptable level can usually be obtained at normal pressure.

<Effects of the Invention> According to the present invention, a liquid in a phase-separated state from water can be separated with high separation efficiency.

The application fields of this separation technology are very wide, including petroleum, chemicals, automobiles, electricity, electronics, printing, rubber, paper, film, textiles, etc.
It can be applied to the separation of liquids that are phase separated from water in all industrial fields such as plastics, artificial leather, dry cleaning, pharmaceuticals, foods, and metals. For example, it can be used to separate water in petroleum refining processes, from water mixtures at gas stations, from automobile gasoline, from kerosene, and from petroleum-based dry cleaning.

<Example> Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 A random web of polyethylene terephthalate having a basis weight of 40/j/rn2 and consisting of ultrafine fibers having an average fineness of 0.05 denier was obtained by a melt blowing method.

This web was calendered, immersed in Poron MR4 weight water solution (manufactured by Shin-Etsu Chemical Co., Ltd.) as a water repellent agent, squeezed uniformly with a mangle at a squeezing rate of 100%, and pre-dried at 100°C for 3 minutes. After that, heat treatment was performed at 180° C. for 1 minute.

The water pressure resistance of the obtained nonwoven fabric was measured according to the JIS-L1092B method, and the result was 650 H20.

However, the water pressure resistance was 80 mm H2O when measured on a non-woven fabric that had not been treated with a water-repellent finish. Using these two types of nonwoven fabrics, an attempt was made to separate a liquid that is in a phase-separated state from water as shown below.

(,) A liquid in which 500C of ethyl ether is mixed and dispersed in 100CC of water. (b) A liquid in which 100Ω of toluene is mixed in 100m of water. (c) Water 1. As a method for separating the liquid mixed with 5 oct of kerosene during the OO work, a separation device as shown in Fig. 1 was prepared and the separation operation was performed.

Filtration rate was determined as an evaluation of separation efficiency. In addition, as a separable egg, the liquid after rinsing was allowed to stand for a day and night, and then it was examined to see if the phases separated. In other words, separation performance was investigated using the phenomenon that when sufficient vibration is applied, a sample that is completely separated will not become cloudy, but if water is mixed in at a level higher than the solubility level, it will become cloudy. The results are shown in Table 1.
As is clear from Table 1 below, it can be seen that the separation according to the present invention using a water-repellent fibrous structure has a high flow rate and extremely excellent separation performance.

Example 2 A random web of polypropylene having a basis weight of 50 g/m2 and consisting of ultrafine fibers having a single fiber fineness of 0.02 denier was obtained by the melt-sollow method.

Using this web, the water pressure resistance according to JIS L-1092B method is 95 tan H2O, 150mm H2O
, 250 mm H2O. Using this sample, ethyl acetate containing water mixed and dispersed was filtered in the same manner as in Example-1.

*The concentration of water in the ethyl acetate of the effluent was measured using a Shimadzu gas chromatography GC4CMe, and the separability was determined by whether water was contained in an amount greater than the water solubility at the temperature during filtration.

As is clear from Table 2, the water pressure resistance is °100 tran.
In the case of the lIc fiber structure of less than H20, it was impossible to separate ethyl acetate and water, but the separation using the fiber structure of the present invention, which showed higher water pressure resistance, showed excellent separation performance. .

[Brief explanation of the drawing]

FIG. 1 shows an example of an apparatus used to carry out the separation method of the present invention. (1) A liquid mixture of water and a liquid in a phase-separated state,
(2) fibrous structure, (3) support, (4) valve. Figure 1

Claims (1)

[Claims] A separation method characterized in that, when separating a liquid that is in a phase-separated state from water, the liquid is selectively permeated using a water-repellent fibrous structure.