JPH0295420A - Liquid separating apparatus - Google Patents

Abstract

PURPOSE:To prevent generation of a concentration boundary film near the surface of a permselective membrane by prompting formation of turbulent flow of a liquid mixture introduced into a primary chamber. CONSTITUTION:The primary chamber 11 at a high pressure side to which a specified liquid mixture contg. a kind of liquid to be separated (e.g., water) and another kind of liquid (e.g., alcohol) is supplied, and a secondary chamber 21 at a low pressure side which contacts with the primary chamber 11 interposing the permselective film 3 (e.g., a film produced by forming an alpha-fluoroacrylic acid copolymer copolymerized with an ethylenic unsatd. compd.) capable of permeating the liquid to be separated selectively, are provided. Further, a stirring means A is installed to the primary chamber 11, with which the turbulent flow of liquid mixture supplied to the primary chamber 11 is prompted. As a result, generation of a concentration boundary film near the surface of a permselective film 3 is inhibited, permeation velocity and permeation efficiency are considerably improved, and the time required for the separation of kind of liquid from another kind of liquid is remarkably shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a liquid separation device for separating a desired liquid from a liquid mixture containing two or more types of liquids.

(Prior Art) In general, a distillation method has been employed for a long time as a method for separating a desired liquid from a liquid mixture containing two or more types of liquids. However, although this distillation method can be applied to cases where there is a large difference in the boiling points of the liquids that make up the liquid mixture, it cannot be applied to separation of liquid mixtures with azeotropic points or liquid mixtures with near-boiling points. There was a problem. Therefore, when separating a desired liquid from such a mixed liquid, for example,
Azeotropic distillation is sometimes adopted, which allows liquid separation by adding a predetermined third component, but this distillation method consumes an extremely large amount of steam, and the addition of the third component There are many problems such as contamination of the separated liquid and failure of the equipment.

Against this background, research and development have been particularly active recently on selectively permeable membranes that allow only specific substances to permeate selectively, and the present applicant is also involved in the development of such selectively permeable membranes. We have already filed an application as Japanese Patent Application No. 1987-35401.

Further, the development of a liquid separation system using a pervaporation method using a selectively permeable membrane as described above is also progressing.

-1- The liquid separation system partitions a primary chamber to which the target mixed liquid is supplied and a secondary chamber in which the separated liquid is stored with the selectively permeable membrane, and vacuums the secondary chamber. By reducing the pressure to a vacuum state using a pressure reducing means such as a pump, the high pressure side (i.e., the primary chamber A desired liquid is allowed to permeate from the side) to the low pressure side (ie, the secondary chamber side).

(Problem to be Solved by the Invention) In a liquid separation system using a pervaporation method using a selectively permeable membrane as described above, only the selected component to be separated is allowed to permeate through the selectively permeable membrane. As pervaporation progresses, a layer depleted of the components to be separated, the so-called -
A borderline membrane may occur. On the other hand, when performing membrane separation via a selectively permeable membrane, the drive saw separates the feed liquid side (in other words, the primary chamber side) and the reduced pressure side (in other words, the secondary chamber side). There is a fact that this is caused by an increase in the partial pressure difference between the target components. Therefore, a decrease in the concentration of the component to be separated near the surface of the permeable membrane due to the formation of a concentration film as described above leads to a decrease in the membrane separation driving force, resulting in a decrease in the degree of d-extremity. Such a decrease in permeation rate leads to a decrease in efficiency in liquid separation and an increase in the time required for liquid separation.The problem with liquid separation using selective permeation membranes is how to reduce the formation of the concentration film. This has become an important technical issue to be solved in equipment.

The present invention has been made in view of the above points, and by promoting the turbulence of the mixed liquid flowing into the primary chamber, a concentration film is formed near the surface of the selective permeation 5@. The purpose is to prevent the

(Means for solving the problem) In the present invention, as a means for solving the two-legged problem,
The following measures have been adopted and will be explained below with reference to the drawings.

In the liquid separation device according to claim 1, the first firebox 11 on the high pressure side is supplied with a predetermined mixed liquid containing the liquid to be separated and the liquid in the pond, and the primary chamber 11. In a device comprising a second firebox 21 on the low-pressure side that is in contact with the liquid to be separated through a selectively permeable membrane 3 that selectively permeates the liquid to be separated, the Stirring means is provided to promote turbulence of the liquid mixture supplied to the primary chamber 11.

In the liquid separation device according to claim 2, the stirring means A is formed by a plurality of stirring rods erected at the center of the mixed liquid flow path in the primary chamber li so as to be perpendicular to the flow of the mixed liquid. 7. It is composed of 7...

Furthermore, in the liquid separation device according to claim 3, AD stirring rods 7.7 are installed upright near the primary chamber side boundary surface of the selectively permeable membrane 3 at the primary chamber side boundary. There is.

Furthermore, in the liquid separation device according to claim 4,
The stirring means A is a wave having alternating concave lines 8a and convex lines 8b that are vertically installed at the center of the mixed liquid flow path in the primary chamber li and extend in a direction perpendicular to the flow of the mixed liquid. It is composed of a plate member 8.

(Function) In the present invention, the following effects can be obtained by the above means.

That is, in the liquid separator according to claim 1, stirring means A is disposed in the primary chamber II to promote turbulence of the mixed liquid supplied to the primary chamber +1. This promotes turbulence of the feed liquid (i.e., mixed liquid) flowing in the primary chamber II, and prevents the formation of a concentration film near the surface of the selectively permeable membrane 3 as much as possible. It will be done.

Further, in the liquid separation device according to claim 2, the stirring means A is formed by a plurality of stirring rods erected at the center of the mixed liquid flow path in the primary chamber 11 so as to be perpendicular to the flow of the mixed liquid. 7. By configuring 7..., the flow path of the supplied mixed liquid repeatedly expands and contracts due to the presence of the stirring rods 7, 7, and becomes turbulent, and this turbulence prevents the formation of a concentration film. This is effectively prevented, and when there is not much pressure difference between the primary chamber Il and the second firebox 21, there is a risk that the selectively permeable membrane 3 may oscillate due to the flow of the mixed liquid. The presence of the rods 7, 7, etc. can also prevent the adjacent selectively permeable membranes 3, 3 from coming into contact with each other.

Furthermore, in the liquid separation device according to claim 3, the stirring rods 7, 7, etc. are installed in the vicinity of the surface of the selectively permeable membrane 3 on the primary chamber 11 side so as to be perpendicular to the flow of the mixed liquid. As a result, the supplied mixed liquid flowing near the surface of the selectively permeable membrane 3 is made into a turbulent flow due to collision with the stirring rod 7゜7..., and this turbulence effectively prevents the formation of a concentration film. In addition, when there is not much pressure difference between the first firebox 11 and the second firebox 21, there is a risk that the selectively permeable membrane 3 will swing due to the flow of the mixed liquid. Adjacent selectively permeable membranes 3 due to the presence of...
．． This also prevents the three members from coming into contact with each other.

Furthermore, in the liquid separation device according to claim 4,
The stirring means A is a wave having alternating concave lines 8a and convex lines 8b that are vertically provided at the center of the mixed liquid flow path in the first firebox 11 and extend in a direction perpendicular to the flow of the mixed liquid. By using the plate member 8, the supplied mixed liquid flows along the grooves 8a and the protrusions 8b of the corrugated plate member 8 and becomes turbulent, and the turbulence causes the formation of a concentration film. is effectively prevented, and primary chamber I
When there is not much pressure difference between I and the second firebox 21, there is a risk that the selectively permeable membrane 3 may move due to the flow of the mixed liquid. 3.3 can also be prevented from coming into contact with each other.

(Effects of the Invention) According to the present invention, the following excellent effects can be achieved.

In the liquid separation device according to claim (2), the first firebox 11
Since the stirring means A that acts to promote turbulence of the liquid mixture supplied to the primary chamber 11 is disposed within the primary chamber 11, the
The turbulent flow of the feed liquid (i.e., mixed liquid) flowing through the selectively permeable membrane 3 is promoted, and the formation of a Ω-degree film near the surface of the selectively permeable membrane 3 is prevented as much as possible. It is possible to significantly improve the permeation membrane (9) and the permeation efficiency, and also to significantly shorten the time required for liquid separation.

Further, as in the liquid separation device according to claim 2, the stirring means A is formed by a plurality of stirring rods which are erected at the center of the mixed liquid flow path in the primary chamber II so as to be perpendicular to the flow of the mixed liquid. 747..., the flow path of the supplied mixed liquid is repeatedly expanded and contracted due to the presence of the stirring rod 77..., thereby creating a turbulent flow, which more effectively prevents the formation of a concentration film. In addition, when there is not much pressure difference between the first firebox 11 and the second firebox 21, there is a risk that the selectively permeable membrane 3 will swing due to the flow of the mixed liquid. The presence of ... can also prevent adjacent selectively permeable membranes 3.3 from coming into contact with each other, making it possible to significantly improve the permeation rate and permeation efficiency and significantly shorten the time required for liquid separation. Of course,
This greatly contributes to improving the durability of the selectively permeable membrane 3, and furthermore, as in the liquid separation device according to claim 3,
The stirring rods 7.7... are connected to the first part of the selectively permeable membrane 3.
Next room I! If it is installed near the side surface so as to be perpendicular to the flow of the mixed liquid, the supplied mixed liquid flowing near the surface of the selectively permeable membrane 3 will become turbulent due to collision with the stirring rods 7, 7, etc. Assuming that the formation of a concentration film is more effectively prevented by the turbulence, the primary chamber! l and second seed 2
When there is not much difference between high and low pressure between
It is also possible to prevent the adjacent selectively permeable membranes 3.3 of the stirring rods F' 7, 7, . Furthermore, more desirable results can be obtained in terms of shortening the time required for liquid separation and improving the durability of the selectively permeable membrane 3.

Furthermore, as in the liquid separation apparatus according to claim 4, the stirring means A is provided upright at a central portion of the mixed liquid flow path in the first chamber 11, and is perpendicular to the flow of the mixed liquid. Alternately continuous concave lines 8a and convex lines 8b extending in the direction of
By constructing the corrugated sheet member 8 having This effectively prevents the generation of
When there is not much pressure difference between the first and second springs 21, there is a risk that the selectively permeable membrane 3 will oscillate due to the flow of the mixed liquid. .3 can be prevented from coming into contact with each other, and desirable results can be obtained in terms of improving the permeation rate and permeation efficiency, shortening the time required for liquid separation, and improving the durability of the selectively permeable membrane 3.

(Embodiments) Hereinafter, some preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Embodiment 1 FIGS. 1 and 2 show a liquid separation device according to Embodiment 1 of the present invention.

The liquid separation device of this embodiment has a plate and frame type module structure, and the arrow in the figure indicates the module alone.

In addition, the liquid separation device of this embodiment uses an alcohol aqueous solution diluted with water as the target mixed liquid, and separates 3 L of water (11°0), which is the component to be separated, from the alcohol aqueous solution by pervaporation. It is used as a device to concentrate alcohol.

This liquid separation device surface (specifically, a liquid separation unit unit) includes a first frame l forming a high-pressure side primary chamber 11 for supplying a mixed liquid (i.e., an aqueous alcohol solution), and a a second frame 2.2 which is arranged adjacent to both sides of the first frame l and forms a low-pressure side secondary chamber 21.21;
It consists of a selectively permeable membrane 3.3 interposed between the frame 1 and the second frame 2.2.

The first frame 1 is made of a rectangular frame body, and a mixed liquid supply port 12 connected to a feed tank 5 via a foot pipe 4 is provided at the lower part of the front frame 1a. Also, the rear frame 1b of the first frame l written in +17j
A discharge port 13 is provided in the l: section for discharging the 6-condensed alcohol υF through which water (ii, o), which is a component to be separated, is permeated and removed. That is, in the primary chamber II formed in the 171st node 1, the mixed liquid is caused to flow from the supply port 12 toward the discharge port 13. Reference numeral 6 is a feed pump.

The second frame 2 is made of a rectangular frame having the same shape as the first frame I, and the second tab 21 formed inside the second frame 2 is connected to the first frame I in the first frame I by the selectively permeable membrane 3.
It is separated from firebox 11.

The second frame 2 is provided with a suction port 22 connected to a vacuum pump (not shown) which acts as a pressure reducing means for reducing the pressure inside the second firebox 21 to a substantially vacuum state.

The selectively permeable membrane 3 is made of an amorphous polymer membrane that has the property of selectively permeating only specific component molecules (in the case of this example, water molecules) contained in the mixed liquid. Only water molecules are removed from the mixed liquid flowing through the chamber 11 into the second fire chamber 21.
It has the effect of allowing it to pass through. The selectively permeable membrane 3 may be made of, for example, an ethylenically unsaturated compound (such as styrene, vinyl chloride, acrylonitrile, hydroxyethyl A film formed by copolymerizing acrylate, acrylic acid, etc.) is used.

Therefore, in the primary chamber 11 formed by the first frame 1, there is a spacer installed between the upper and lower frames 1c and 1d of the first frame 1 at the center of the mixed liquid flow path, and in the front-rear direction. (In other words, a plurality of stirring rods 7, 7, . . . are arranged in parallel at predetermined intervals in the mixed liquid flow direction). The outer diameter of the stirring rod 7 is determined to be smaller than the IJ of the first frame 1, and due to the presence of the stirring rod 7. The mixed liquid flow path leading to this point is configured to repeatedly expand and contract. That is, due to the presence of the stirring rods 7.7, 1. The mixed liquid flow path is enlarged.
By repeating the contraction, it is possible to promote turbulence by increasing the flow velocity near the surface of the selectively permeable membrane 3.

That is, in this embodiment, the stirring rods 7.7...
It is supposed to act as a stirring means A that promotes turbulence of the mixed liquid flowing in the firebox 11. Also,
When starting or stopping the device, the first firebox 11
When there is not much difference in high and low pressure between the firebox and the second firebox 21,
Although the selectively permeable membrane 3 may oscillate due to the flow of the mixed liquid, the presence of the stirring rod 7 prevents the first firebox 1 from moving.
1 Prevent the selectively permeable membranes 3.3 from coming into contact with each other l-
be done. In other words, the stirring rods 7.7 also function as spacers that maintain the distance between the selectively permeable membranes 3.3.

Next, the operation of the illustrated liquid separation device will be explained.

First, an alcohol aqueous solution (i.e., alcohol diluted with water) is continuously supplied from the feed tank 5 to the mixed liquid supply port 12 via the feed pump 6, and is supplied to the first firebox according to its supply and discharge speed. It flows slowly inside 11.

On the other hand, at the same time as the alcohol aqueous solution is supplied to the first firebox 11, the pressure in the second firebox 21 is reduced to a substantially vacuum state by the operation of the pressure reducing means, and as a result, the primary A pressure difference greater than a predetermined value is realized between the chamber 11 side and the second firebox 21 side.

As described above, the selectively permeable membrane 3 in this embodiment is made of an amorphous polymer membrane that has the property of allowing only water molecules, which are the components to be separated, to pass through. , the primary firebox 11 and the second firebox 2
The water molecules permeate from the first firebox 11 to the second firebox 21 at a permeation rate proportional to the partial pressure difference between the first firebox 11 and the second firebox 21. Thus, the first
Due to the permeation and separation of water molecules from the firebox 11 to the second firebox 21, the alcohol aqueous solution flowing through the primary chamber tl is concentrated and becomes highly concentrated alcohol, which is discharged from the discharge port 13.

In this case, water molecules permeate through the selectively permeable membrane 3 through adsorption of water molecules onto the surface of the selectively permeable membrane 3 due to suction energy from the high-pressure side to the low-pressure side, and into the selectively permeable membrane 3 due to molecular hyperactivity associated with dissolution. The processes of dissolution, diffusion of water molecules in the selectively permeable membrane 3 to the low pressure side, and desorption of water molecules from the surface of the selectively permeable membrane 3 on the low pressure side are carried out in sequence. It is known that the permeation rate in the mechanism of water molecule permeation as described above depends on various factors, but an important factor governing the permeation rate is the difference between the high pressure side and the low pressure side of the selectively permeable membrane 3. There is a partial pressure difference between the components to be separated (in this example, water molecules). It is a well-known fact that the partial pressure difference is determined by the concentration difference of the component to be separated between the high pressure side and the low pressure side of the selectively permeable membrane 3.

However, when the selective permeation of water molecules through the selectively permeable membrane 3 is performed continuously, the first firebox 1 of the selectively permeable membrane 3
A layer deficient in water molecules (in other words, a layer with a high alcohol concentration) is generated on the first side (ie, the high pressure side). This is generally called a concentration film, and due to the formation of this concentration film, the difference in concentration of the component to be separated (+ molecules) between the high pressure side and the low pressure side of the selectively permeable membrane 3 becomes extremely small. A problem arises in that the permeation rate of molecules is significantly reduced (see Figure 7). The formation of a two-legged concentration film is noticeable when the flowing fluid forms a laminar flow, and the formation of the concentration film can be prevented by promoting turbulence in the flowing fluid.

Therefore, as in the present embodiment, in the primary chamber ll formed by the first frame 1 in 11;
A plurality of stirring irons L are installed between B and are arranged in parallel at a predetermined interval in the front-rear direction (in other words, in the direction of flow of the mixed liquid).
;' 7 , 7 . . . is provided, the mixed liquid flow path from the supply port 12 to the discharge port I 3 in the first firebox 11 is repeatedly expanded and contracted by the stirring rods 7 , 7 . Turbulent flow is promoted by increasing the flow velocity on and near the surface of the selectively permeable membrane 3 on the primary chamber II side. The promotion of turbulence prevents the formation of a concentration film on the high pressure side of the selectively permeable membrane 3 (in other words, on the primary chamber 11 side).
Therefore, the components to be separated (water molecules) are continuously supplied to the high-pressure side surface of the selectively permeable membrane 3. Therefore, the difference in concentration of the component to be separated between the high pressure side and the low pressure side of the selectively permeable membrane 3 can always be maintained at a predetermined value or more -L, and the permeation rate and permeation efficiency can be improved. .

In addition, when there is not much pressure difference between the first firebox 11 and the second firebox 21, such as when starting or stopping the device, the selection can be made based on the flow of the mixed liquid flowing through the first firebox 1■. Although the selectively permeable membrane 3.3 may oscillate, the stirring rod 7 acts as a spacer to prevent contact between the selectively permeable membrane 3.3 and improve durability. Contribute.

Embodiment 2 FIGS. 3 and 4 show a liquid separation device according to Embodiment 2 of the present invention.

In the case of the liquid separator of this embodiment, the stirring rod 7 provided in the primary chamber il has an extremely small diameter compared to that of the first embodiment, and is located on both sides of the primary chamber II. They are arranged in parallel near the surface of the selective passage membrane 33. In other words, the upper and lower frames 1 c, I of the first frame l
A plurality of 7.7... are arranged in two columns at a predetermined interval in the flow direction of the mixed liquid at a position close to the selective passage membrane 3.3 between d and 3.3. The rest of the configuration is the same as in 6 of Embodiment 1 in Section 1iii, so the explanation will be omitted to avoid duplication.

With the above-mentioned configuration, in the overnight heating device of this embodiment, the flow-4 filtration mixed liquid (
The aqueous alcohol solution) collides with the agitation door 7 near the surface of the selective passage membrane 3 to create a turbulent flow, which makes the concentration film more effective than in the case of Example I described above. In this example, the stirring rods 7.7, etc. are used to maintain the spacing between the selectively permeable membranes 3.3 as in Example 1 above. What does it do to act as a spacer?

Embodiment 3 FIGS. 5 and 6 show a liquid separation device according to Embodiment 3 of the present invention.

In the case of the liquid separator of this embodiment, in the primary chamber ll,
A corrugated plate member 8 is provided at the center of the mixed liquid flow path in the primary chamber 11 and has alternating concave lines 8a and convex lines 81 extending in a direction perpendicular to the flow of the mixed liquid. ing. The corrugated plate member 8 acts as a stirring means A that promotes turbulence of the liquid mixture flowing through the primary chamber II.

In other words, the corrugated plate portion 8 is installed at the center of the mixed liquid flow path between the upper and lower frames 1c and ld of the first frame 1. The rest of the configuration is the same as that of the first embodiment, so the explanation will be omitted to avoid duplication.

With the above configuration, in the liquid separation device of this embodiment, the mixed liquid (alcohol aqueous solution) flowing in the first firebox 11 can be
b, the flow becomes turbulent, and the formation of a concentration film is prevented as in the case of the first embodiment described above. Note that the corrugated plate member 8 in this embodiment also functions as a spacer for maintaining the distance between the selectively permeable membranes 3, 3, as in the first embodiment.

In the above description, the example is applied to the case where a water component is separated from an aqueous alcohol solution to obtain a highly concentrated alcohol. Of course, it is also applicable to separation of specific components from other liquid mixtures (for example, azeotropic liquid mixtures, near-boiling liquid mixtures, etc.).

Further, the present invention is not limited to the configurations of the above embodiments, and it goes without saying that the design can be changed as appropriate without departing from the gist of the invention.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing a module structure of a liquid separation device according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of the liquid separation device shown in FIG. 1, and FIG. 3 is an embodiment of the present invention. 2 is an exploded perspective view showing the module structure of the liquid separation device according to No. 2;
4 is a cross-sectional view of the liquid separation device shown in FIG. 3, FIG. 5 is an exploded perspective view showing the module structure of the liquid separation device according to Embodiment 3 of the present invention, and FIG. FIG. 7, which is a cross-sectional view of the liquid separation device, is a characteristic diagram showing the relationship between the concentration difference of water molecules at the interface of the selectively permeable membrane and the permeation rate of water molecules. 3... Selective permeable membrane 7... Stirring rod 8... Corrugated plate member 8a... Concave strip 8b... Convex Article II...Primary chamber 2]...Secondary chamber A...Stirring means Fig. 2 Fig. 4 Fig. 21 Secondary 'J6 Fig. 6 Figure 7

Claims (1)

[Claims] 1. A primary chamber (11) on the high pressure side to which a predetermined mixed liquid containing the liquid to be separated and other liquids is supplied, and for the primary chamber (11) A liquid separation device comprising: a secondary chamber (21) on the low pressure side that is in contact with the secondary chamber (21) through a selectively permeable membrane (3) that selectively permeates the liquid to be separated; ) A liquid separation device characterized in that a stirring means (A) is disposed in the interior of the primary chamber (11) to promote turbulence of the mixed liquid supplied to the primary chamber (11). 2. In the liquid separation device according to claim 1, the stirring means (A) is erected at the center of the mixed liquid flow path in the primary chamber (11) so as to be perpendicular to the flow of the mixed liquid. A liquid separation device characterized by comprising a plurality of stirring rods (7), (7)... 3. In the liquid separation device according to item 1 above, the stirring rods (7), (7)... are connected to the selectively permeable membrane (3).
A liquid separation device characterized in that the liquid separation device is installed near the surface on the side of the primary chamber (11) so as to be perpendicular to the flow of the mixed liquid. 4. In the liquid separation device described in item 1 above, the stirring means (A) is provided upright at the center of the mixed liquid flow path in the primary chamber (11) and is perpendicular to the flow of the mixed liquid. Alternately continuous concave lines (8a) and convex lines (8a) extending in the direction
8b) A liquid separation device characterized in that it consists of a corrugated plate member (8).