JPH0665362B2 - Separation method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for separating a liquid that is in a phase separation state from water from water. More specifically, a water-repellent fiber structure is used, and the fact that the fiber structure has the ability to selectively permeate only a liquid that is in a phase-separated state with water is used to separate water from the liquid. Regarding the method.

<Prior Art> Conventionally, as a method for separating oil or organic solvent and water from a liquid phase in which a liquid such as oil or an organic solvent insoluble in water and water are mixed, (1) oil-water mixed phase is used. Method of heating and distilling, or method of physically separating by utilizing centrifugal force; (2) Method of chemically separating by adding demulsifying agent or coagulant to oil-water mixed phase;
(3) An adsorption separation method that uses an adsorbent that selectively adsorbs only the oil phase; (4) a separation method that appropriately selects and uses these methods. However, in any of the methods, there are drawbacks such that the separation cannot be completed completely and the cost is high.

In addition, recently, a magnetic field separation method has 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 the magnetic phase from the oil / water mixed phase. In this method, when the oil phase is contained in a large amount or the oil phase exists as a dispersion medium, the amount of expensive magnetic fine powder added remarkably increases, and the oil phase and magnetic fine powder are added. A large amount of stirring energy is required for sufficient contact. Further, this magnetic fine powder has a practical problem that it is difficult to reuse even if it is recovered from the oil phase.

Further, as a membrane separation technique using a polymer microporous membrane, methods such as permeation, dialysis, and electrodialysis are known, but in each case, since the liquid permeability is small, the separation efficiency is poor, and the device is large. There is a drawback that it has to be realized.

<Problems to be Solved by the Invention> In view of the drawbacks of the prior art, the present inventors have a large liquid permeability and a high separation efficiency when separating a liquid phase-separated from water from water. As a result of examining the technology, the present invention has been reached.

<Means for Solving Problems> In the separation method according to the present invention, when separating a liquid in a phase separation state from water, the liquid is selectively permeated by using an organic fiber structure having water repellency. Characterize things.

The "phase separated state" in the present invention means that an aqueous phase is dispersed in a liquid phase, or a liquid phase is dispersed in an aqueous phase, or the whole is sandwiched by only one interface to form two layers. It is said that the aqueous phase and the liquid phase coexist regardless of the form of physical dispersion of the two phases, such as being separated into two. Therefore, in the present invention, not only those that are in a phase-separated state from the beginning, but also those that are in a phase-separated state by adding a solvent having a low solubility in water and a high solubility in a liquid of interest to a homogeneous solution, or water. In addition, a solution in which a certain compound is dispersed is added to a solvent having a low solubility in water and a high solubility in a compound of interest to form a phase-separated state.

In the present invention, the liquid that can be particularly preferably separated is a liquid that is substantially insoluble in water, and the surface tension of the liquid is
Those of 55 dyne / cm or less are included. Surface tension is 40dyne
Liquids of less than / cm have even better separation efficiency. As typical examples of these liquids, various paraffin hydrocarbons such as n-pentane, n-hexane, n-heptane, n-octane and n-decane, petroleum ether, ligroin, gasoline, kerosene,
Mixtures of various hydrocarbon compounds such as petroleum naphtha, aromatic hydrocarbon compounds such as benzene, toluene, xylene, alicyclic hydrocarbon compounds represented by cyclopentane and cyclohexane, various mineral oils, vegetable oils, animal oils, various ethers , Ketones, esters, alcohols, phenols and the like.

The "fiber structure having water repellency" referred to in the present invention is JIS
Water pressure measured by -L-1092b method 100 mm H ₂ O or more, preferably of those 200mH ₂ O~2000mmH ₂ O. The level of water pressure resistance may be appropriately selected usually within the range of 10000 mmH ₂ O as needed depending on the conditions of the separation operation.

The form of the fibrous structure of the present invention may be any of woven fabric, knitted fabric, non-woven fabric, mat-like, felt-like, and sheet-like ones, and fine fibers or fibrillated fibers having a single filament denier may be used,
A high-density woven fabric such as a high-density woven fabric is preferably used because it is easy to obtain high water pressure resistance. In terms of liquid permeability, knitted fabric,
Nonwoven fabrics and sheet-shaped ones are excellent under the same water pressure resistance, and in particular, in the present invention, a fiber structure having a single yarn fineness of 1 denier or less is used as a fiber structure having high water pressure resistance and high liquid permeability. Examples include non-woven fabric and sheet-like materials.

The fibers constituting the fiber structure of the present invention include polyester-based copolymers such as polyethylene terephthalate, polyethylene terephthalate adipate, polyethylene terephthalate isophthalate, polyethylene terephthalate sebacate, polyethylene terephthalate dodecanedioate, and polybutylene terephthalate. Fiber, Polyhexamethyleneadipamide, Polyhexamethylenesebacamide, Polyhexamethylenedecamide, Polyhexamethylenehexamide, Polycapramide, Polyoctamide, Polynonamide, Polyamide fiber such as Polydecamide, Polydodecamide, Polytetramide, Polypropylene, Polyethylene, etc. The polyolefin fiber of. These fibers are used alone or in combination.

As a specific example of the fiber structure having a water pressure resistance of 100 mmH ₂ O or more, which is useful in the present invention, a structure made of a hydrophobic fiber such as polypropylene fiber or polyethylene fiber, or a water repellent treatment is applied to the fiber structure. A structural body having water repellency is given by the above. The water repellent finish of the fiber structure may be carried out by an ordinary method. For example, a known water repellent finish such as a silicone resin such as dimethyl silicone, a paraffin resin, or a wax resin may be used at the time of manufacturing the yarn or in the fiber structure. It may be applied to the body by a method such as padding, dipping, spraying or exhausting. Further, heat treatment may be performed after applying a water repellent agent, if necessary.

The separation method in the present invention is not particularly limited, and various over-types such as a batch type or a continuous type such as a vertical type, a horizontal type and a multi-stage type can be applied. An example of the separating device is shown in FIG. In the figure, the latter liquid of the mixed liquid (1) of water and a liquid in a phase-separated state was supported by the vertical fiber structure (2) and optionally the support (3). The horizontal fiber structure (2) is selectively permeated and the valve (5) is opened for recovery.

From the viewpoint of separation efficiency, it is preferable to make the fiber structure bellows-shaped so as to increase the excess area and to mount the fiber structure on the reactor. Further, overpressurization can be performed at a pressure lower than the water pressure resistance of the fibrous structure. It may be passed while stirring. In particular, since the separation method of the present invention has a higher liquid permeability than a film-like microporous membrane, it is usually possible to obtain a practically problem-free separation efficiency at normal pressure.

<Effects of the Invention> According to the present invention, a liquid that is in a phase separation state with water can be separated with high separation efficiency. The field of application of this separation technology is very wide. Petroleum, chemicals, automobiles, electricity, electronics, printing, rubber, paper, film, fiber, plastic,
It is applicable to artificial leather, dry cleaning, pharmaceuticals, foods, metals and separation of water and liquids in phase separation state in all fields of industry. For example, it can be used for separation of water in a petroleum refining process, separation from a water mixture of a gas station, separation of water in automobile gasoline, separation of water in kerosene, separation of water for petroleum dry cleaning, and the like.

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

Example 1 A random web of polyethylene terephthalate having a basis weight of 40 g / m ² made of ultrafine fibers having an average fineness of 0.05 denier was obtained by the melt blowing method. This web was calendered, dipped in a 4% by weight aqueous solution of Poron MR (manufactured by Shin-Etsu Chemical Co., Ltd.) as a water repellent agent, uniformly squeezed with a mangle at a squeezing rate of 100%, and then pre-dried at 100 ° C. for 3 minutes. Heat treatment was performed at 180 ° C. for 1 minute. The water resistance of the obtained non-woven fabric is JIS-L1092.
As a result of measurement by Method B, it was 650 mmH ₂ O.

Also, for comparison, the water resistance was 80 mmH ₂ O when measured on a non-water repellent non-woven fabric. An attempt was made to separate water and a liquid in a phase-separated state shown below using these two types of nonwoven fabrics.

(A) Liquid in which ethyl ether 50c.c. is mixed and dispersed in water 100c.c., (b) Liquid in which toluene 100c.c. is mixed in water 100c.c. (c) In water 100c.c. As a liquid separating method in which kerosene 80c.c. was mixed with the above, a separating apparatus as shown in Fig. 1 was prepared and a separating operation was performed.

Overspeed was obtained as an evaluation of separation efficiency. In addition, as the separation performance, it is examined whether the liquid after passing is left to stand for a whole day and night and then phase-separated. That is, the separation performance was investigated by utilizing the phenomenon in which, when sufficient vibration was given, those which could be completely separated did not become turbid, but when water was mixed in at a level higher than the solubility, white turbidity was caused. The results are shown in Table 1.

As is clear from Table 1, the separation according to the present invention using the fibrous structure having water repellency has a large overspeed and is extremely excellent in separation performance.

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

Using this web, the water pressure resistance according to JIS L-1092B method
95mmH ₂ O, 150mmH ₂ O, was subjected to pressure processing as a 250mmH ₂ O. Using this sample, the same procedure as in Example 1 was performed except that water was mixed and dispersed in ethyl acetate.

* The concentration of water in the ethyl acetate in the excess liquid was measured using a gas chromatography GC4CM manufactured by Shimadzu Corporation, and the separability was checked based on whether or not water was contained in excess of the water dissolution capacity at the transient temperature.

As is clear from Table 2, in the case of a fiber structure having a water pressure resistance of less than 100 mmH ₂ O, separation of ethyl acetate and water was impossible, but a fiber structure of the present invention having a water pressure resistance higher than that was obtained. The separation used showed excellent separation properties.

[Brief description of drawings]

FIG. 1 shows an example of an apparatus used for carrying out the separation method of the present invention. (1) Water and a mixed liquid of water and a liquid in a phase separation state,
(2) Fiber structure, (3) support, (4) valve.

Claims (2)

[Claims] 1. When separating a liquid that is in a phase-separated state from water, it is composed of at least one fiber selected from the group consisting of polyester fibers, polyamide fibers and polyolefin fibers, and has a water pressure resistance of 100 mmH ₂ O or more. A separation method, which comprises selectively permeating the liquid using a fibrous structure. 2. The water repellent finish of the fibrous structure with at least one resin selected from the group consisting of silicone resins, paraffin resins and wax resins.
Separation method described.