JP2003144803A - Two-liquid countercurrent extractor and extraction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous countercurrent extractor having high efficiency. SOLUTION: A rotating member which can be rotated around a shaft disposed in the direction almost perpendicular to the interface between the fluid to be extracted and an extracting agent and produce a swirling current in the shaft direction by the rotation is arranged in the body of this two-liquid countercurrent extractor where the fluid to be extracted is brought into countercurrent contact with the extracting agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-liquid continuous countercurrent extraction device used for liquid-liquid extraction generally performed industrially and an extraction method using the same.

[0002]

2. Description of the Related Art Extraction operations have been conventionally used for recovering active ingredients from mixtures and removing unnecessary ingredients. There are two types of extraction operation, continuous type and batch type. In addition, the extractant (extractant) and the agent (extractant) from which the active ingredients and impurities are removed by the extract operation flow countercurrently and come into contact with each other to carry out the extraction. There is extraction and co-current extraction in which both come into contact while flowing in the same direction. Continuous extraction is generally performed industrially, and the countercurrent extraction method is often used because efficient extraction can be performed.

In the countercurrent extraction method, generally, a liquid having a high specific gravity (heavy liquid) of the extractant and the extractant is placed in the cylindrical extractor body from above, and a liquid having a low specific gravity (light liquid) is placed in the downside. The liquid-liquid extraction is performed by supplying more and contacting in the main body. At this time, usually, the top and bottom of the extractor main body have a discharge mechanism for taking out a liquid with a small specific gravity and a liquid with a large specific gravity from the extractor main body to the outside of the system, and always keep the liquid interface of these liquids at a fixed position. To keep the extraction efficiency constant. At this time, it is general that, of the extractant and the extractant, one having a larger flow rate supplied to the extractor main body is used as the dispersed phase for extraction. Furthermore, in order to increase the contact area of liquid-liquid contact by reducing the dispersed particle size in the extractor body and improve the extraction efficiency, a porous plate or packing is provided in the extractor body. Alternatively, an extractor provided with a rotating disk or the like may be used for the purpose of reducing the diameter of dispersed particles.

[0004]

By the way, in the case of an extractor which does not have a driving part such as a perforated plate or the like, buoyancy and gravity are the factors that make the droplets of the dispersed phase small, so the extraction efficiency depends on the system. However, the theoretical number of theoretical separation stages per unit height is about 0.8 to 1.2 (stages / m). Therefore, when a large number of theoretical plates are required, a high height extractor is required.

Further, in an extractor such as an extractor (RDC) provided with a rotating disk having a drive unit, the number of theoretical separation stages per unit height is 2 to forcefully reduce the droplets of the dispersed phase by power. It is about 4 (steps / m), but conversely, the liquid load (TST: Total specific thru
However, there is a problem in that it is necessary to increase the diameter of the extractor. The general range of TST is 30 to 50 [m ³ / m ² with an extractor equipped with a perforated plate.
· Hr] and 15 to 30 [m ³ / m ² · hr] in RDC (Chemical Engineering June 1981 No. 5)
3 to 58). Incidentally, various large continuous countercurrent extraction devices have been developed and used in the mass industry.

However, pharmaceutical synthesis and organic fine,
Alternatively, in fields such as laboratory-level experiments in which a large amount of liquid to be used for extraction cannot be obtained, there is no continuous countercurrent extraction device that is smaller and more efficient than before, so development is required. It was

[0007]

As a result of intensive studies to solve the above problems, the present inventors have made the droplets of the dispersed phase small and the contact time between the dispersed phase droplets and the continuous phase small. A stirring rod that can be lengthened, specifically, a rotating member that is rotatable about a direction substantially perpendicular to the interface between the two liquids and that generates a swirling flow in the axial direction by rotation is provided in the extraction main body. Then, they have found that even if the extractor body is miniaturized, sufficient extraction efficiency can be reproduced, and the above-mentioned problems can be solved, resulting in the present invention.

That is, the gist of the present invention is a two-liquid countercurrent extraction device for countercurrently contacting the extractant and the extractant in the main body, which is rotatable about a direction substantially perpendicular to the interface between the two liquids. Further, the present invention relates to a two-liquid countercurrent extraction device characterized by having a rotating member in the main body that produces a swirling flow in the axial direction by rotation.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The extraction device of the present invention is a two-liquid countercurrent extraction device in which the extraction liquid and the liquid to be extracted are brought into countercurrent contact in the extractor body,
A rotary member that is rotatable about a direction substantially perpendicular to the interface between the two liquids and that generates a swirling flow in the axial direction by the rotation is arranged in the extractor body. With such a structure, a swirl flow is generated in the liquid-liquid extraction system by rotating this member during extraction, which reduces the moving speed of dispersed particles in the continuous phase, and also the particle size. Becomes smaller and the liquid-liquid contact time increases, so the extraction efficiency improves. Furthermore, the improved extraction efficiency enables efficient extraction even in a small amount of liquid-liquid extraction.

In the present invention, the arrangement and shape of the rotary member that produces a swirling flow in the axial direction by rotation are arbitrary, but among them, the rotary member is a rod-shaped rotary member having a wing or screw structure, and its longitudinal direction rotates. It is preferable to use the one disposed in the main body in the axial direction because it has a simple structure and can be easily replaced or inspected for maintenance, and the effects of the present invention can be sufficiently exerted. In particular, it is preferable that the screw structure is one in which a linear member having a diameter smaller than that of the cylindrical rod member is spirally arranged on the outer circumference of the cylindrical rod member. In this case, the linear member may be a linear member having a diameter smaller than that of the rod-shaped rotating member and may have an arbitrary thickness and sectional shape.

The rotating member is disposed in the extractor main body, preferably at a substantially central position in the extractor main body, such that the one end is connected to a power source such as a motor so as to be rotatable. The material of the rotating member is not particularly limited as long as it is resistant to the liquid medium used for extraction, metal, Teflon (registered trademark), etc., but a flexible rod-shaped material is made of metal wire. Are preferred. The diameter of the linear member provided on the outer periphery of the rotating member needs to be smaller than that of the stirring rod, and is 0.05 to 0.5 times, preferably 0.1 to 0.4 times the diameter of the rotating member. . The diameter of the stirring rod is not particularly limited, but 0.1 to 0.6 times the inner diameter of the cylindrical column,
It is preferably 0.2 to 0.4 times. If the inner diameter of the cylindrical column is extremely large, in order to improve the stirring efficiency,
Two or more stirring rods may be inserted.

When the linear member is spirally arranged on the rotating member, the winding method is as follows:
The flow direction of the swirling flow occurring in the column is opposite to the flow direction of the dispersed phase. For example, in the case of heavy liquid dispersion, it is wound so that the swirl flow is directed upward, and in the case of light liquid dispersion, the swirl flow is directed downward. Although the shape of the extractor main body is arbitrary, it is preferable that the extractor main body is usually cylindrical in terms of production and maintenance. The height of the extractor body is not particularly limited, but if the height is too small, the extraction efficiency is poor, so a cylindrical column having a height of 50 cm or more is usually used. The extraction temperature can be adjusted by making the cylindrical column a jacket type and flowing a heat medium through the jacket.

The size of the supply pipe diameter for supplying the extractant and extractant to the extractor main body is not particularly limited, but it is preferable that the droplet phase is as small as possible in the dispersed phase. Therefore, the diameter of the supply pipe on the side of the dispersed phase is, for example, 0.2 to 3 mm when the cross-sectional diameter of the extractor body is 2.5 cm, preferably 0.
It is 5 to 1 mm. When the rotation speed of the stirring rod at the time of extraction is larger, the extraction efficiency is better because the dispersed phase droplets are smaller. However, if the rotation speed is too large, carryover, flooding and other operation hindrances occur, so it is usually 50
To 1000 rpm, preferably 200 to 500 rp
m.

In selecting the disperse phase and the continuous phase, it is generally preferable to use the larger flow rate as the disperse phase. However, in the case of a system having stable operation inhibiting factors such as emulsion and dirt layer, the disturbance is disturbed. It is also possible to select a dispersed phase or a continuous phase that does not easily cause When performing extraction, generally, a light liquid is supplied from the lower part of the extractor body and a heavy liquid is supplied from the upper part by a pump. The extracted liquid overflows from the upper part and continuously withdraws from the lower part using a control valve or a manual valve, so that the interface is operated at a constant level.

In the extraction method of the present invention, any extractant or extractant can be used. However, if the interfacial tension at the interface between the two liquids is too large, the extraction efficiency may be poor, so the extractant may be salts or the like. Those having a low electrolyte content are preferable, and those not containing such an electrolyte are preferable. In the extraction method of the present invention, using the above apparatus, the interfacial tension of the two liquids is 20 dyn / cm or less, and especially 10 dyn / cm or less,
Particularly, it is preferable to perform countercurrent extraction with two liquids under the condition of 5 dyn / cm or less.

The interfacial tension of the two liquids in the present invention is the liquid-liquid interfacial tension when the extractant and the extractant are in a liquid-liquid equilibrium state under the temperature conditions for extraction. Specifically, it is measured by the liquid-liquid interfacial tension under the extraction temperature conditions of the "extraction residue" and the "liquid obtained by extraction", and in the present invention, the interfacial tension of the two liquids is 20 dyn / cm or less. Is preferred. The method for measuring such liquid-liquid interfacial tension is not particularly limited, and any conventionally known method such as a capillary rise method or Bartel-
The Miller method, the Donnan pipette, etc. can be used. The interfacial tension of the two liquids in the present invention may be measured, for example, as follows.

First, before the actual two-liquid countercurrent extraction, the concentration and type of the target substance to be extracted, the liquid containing the target substance (that is, the extraction material), and the extraction agent are changed, and ( A two-liquid interfacial tension profile (of the extraction material and the extraction material) is obtained. And in line with the extraction fee for the actual two-liquid countercurrent extraction,
It is only necessary to select and use an extractant having an interfacial tension of the two liquids of 20 dyn / cm or less.

[0018]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the examples as long as the gist thereof is not exceeded. In the following examples, the interfacial tension was measured by the capillary rise method. Example 1 A SUS304 wire rod having a diameter of 2 mm was spirally wound around a SUS304 round bar having a diameter of 8 mm and a length of 1300 mm. The spiral coil should be wound in such a direction that an upward swirling flow is generated when stirring, and the winding interval is 20.
mm. In addition, the adhesion of the spiral coil and the stirring rod,
It was performed by partially spot welding. The stirring rod manufactured in this way was inserted into the center of a glassy cylindrical column having a jacket with an inner diameter of 25 mm and a height of 1000 mm, the stirring rod upper part was fixed with a stirring motor, and the lower part was fixed with a Teflon bearing. I put it out. Furthermore, auxiliary equipment such as a liquid supply pump and a liquid withdrawal line was installed, and an extraction tower was manufactured as shown in the attached figure.

In this extraction tower, an ε-caprolactam aqueous solution (concentration: 70% by weight) having a 7: 3 weight ratio of ε-caprolactam and water was used as a heavy liquid, and benzene was used as a light liquid.
The ε-caprolactam aqueous solution was 270 g / hr, the flow rate ratio of benzene was 518 g / hr, the rotation speed was 300 rpm, and extraction was performed with a heavy liquid dispersion system while circulating water at 40 ° C. in the jacket portion.

The liquid load (TST) in this case is 188 [c]
m ³ / cm ² · hr], and the ε-caprolactam concentration in the ε-caprolactam aqueous solution (extraction residue) after the extraction operation was reduced to 1.2% by weight. The interfacial tension between the raffinate and the benzene solution containing ε-caprolactam in equilibrium with the raffinate composition (hereinafter abbreviated as liquid-liquid interfacial tension) was 16.
It was 0 dyn / cm. The number of theoretical plates extracted from the liquid-liquid equilibrium data was as high as 6 theoretical plates. Example 2 It carried out like Example 1 except having used the same extraction tower as Example 1, and making the number of rotations 200 rpm. as a result,
The concentration of ε-caprolactam in the residue was reduced to 1.9% by weight. The liquid-liquid interfacial tension is 15.0 dyn / c.
It was m. Example 3 Example 3 was repeated except that the same extraction column as in Example 1 was used and the temperature was 30 ° C. As a result, the concentration of ε-caprolactam in the extraction residue was reduced to 2.7% by weight. The liquid-liquid interfacial tension was 13.6 dyn / cm. Example 4 Example 1 was repeated except that the same extraction column as in Example 1 was used, the temperature was 23 ° C., and the rotation speed was 300 rpm. As a result, the concentration of ε-caprolactam in the extraction residue was 15
It had been reduced to weight%. The liquid-liquid interfacial tension is 8.0.
It was dyn / cm. Example 5 It carried out like Example 4 except having used the same extraction column as Example 1, and making the rotation speed 350 rpm. as a result,
The concentration of ε-caprolactam in the extraction residue was reduced to 8.5% by weight. The liquid-liquid interfacial tension was 13 dyn / cm.

The number of theoretical plates extracted from the liquid-liquid equilibrium data was as high as 6 theoretical plates. Example 6 It carried out like Example 1 except having used the same extraction column as Example 1, and making temperature into 23 ° C. As a result, the concentration of ε-caprolactam in the extraction residue was reduced to 9.8% by weight. The liquid-liquid interfacial tension was 9.0 dyn / cm. Comparative Example 1 The same extraction column as in Example 1 was used, and ammonium sulphate, water and ε-caprolactam as heavy liquid were added to this extraction column at 39: 60.3:
0.7 weight ratio of ε-caprolactam-containing ammonium sulfate aqueous solution (ε
-Caprolactam concentration: 0.7% by weight), benzene as a light liquid, 140 g / hr of an aqueous solution of ammonium sulfate containing ε-caprolactam, and a flow rate ratio of benzene of 400 g / hr.
In addition, the rotation speed is fixed at 400 rpm and 4
Extraction was performed in a heavy liquid dispersion system while circulating warm water of 0 ° C.

As a result, the concentration of ε-caprolactam in the extraction residue was reduced to 0.09% by weight. Also, the number of theoretical plates was as low as one. The interfacial tension between the extraction residue and the benzene solution containing ε-caprolactam in equilibrium with the extraction residue was 25 dyn / cm.

[0023]

According to the countercurrent extraction method using the apparatus of the present invention, a stirring rod provided with an accessory in an oblique direction is installed at the center of the cylindrical column, and swirling in the direction opposite to the traveling direction of the dispersed phase. It becomes possible to rotate the stirrer so that the flow occurs, and it becomes possible to provide an efficient continuous countercurrent extraction device. Moreover, as in the case of pharmaceutical synthesis, organic fines, or laboratory-level experiments, extraction can be performed. It is industrially advantageous because it is possible to develop a small device that can be used even in a field where a large amount of liquid to be used cannot be obtained.

Claims (4)

[Claims] 1. A two-liquid countercurrent extraction device for countercurrently contacting an extractant and an extractant in a main body, which is rotatable about an axis substantially perpendicular to a two-liquid interface and is rotated in the axial direction. A rotary member that produces a swirl flow is provided in the main body.
Liquid countercurrent extraction device. 2. The rotating member is a rod-shaped rotating member having a wing or screw structure, and is arranged in the main body so that its longitudinal direction coincides with the rotation axis direction. Two-liquid countercurrent extraction device. 3. The rod-shaped rotating member has a screw structure, and a linear member having a diameter smaller than that of the cylindrical rod-shaped member is spirally arranged on the outer periphery of the cylindrical rod-shaped member. The two-liquid countercurrent extraction device according to claim 2. 4. The apparatus according to claim 1, wherein the interfacial tension between the extractant and the extractant in equilibrium is 2 or less.
An extraction method of an extractant, characterized in that the extractant and the extractant are brought into countercurrent contact with each other under the condition of 0 dyn / cm or less.