JPH0636841B2 - Pressurized freeze concentrator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pressurization type freeze concentration apparatus for producing a concentrated solution having a high solute concentration from an aqueous solution containing water such as various beverages and chemicals as a solvent.

[Prior Art] A solution consisting of a solute and a solvent (water) is once frozen to form an ice crystal, and the ice crystal is pressurized and heated to separate a solution having a high solute concentration from the ice crystal. So-called pressure-type freeze concentrators for producing concentrated liquids have been known for some time.

Such a device utilizes a physical phenomenon in which the freezing point of a solution changes depending on the concentration of a solute with respect to a solvent (water) and the pressure applied to the solution.

That is, the physical properties are used in which the freezing point is lowered as the pressure applied to the aqueous solution is higher and the concentration of the solute contained in the aqueous solution is higher.

FIG. 2 shows a schematic system diagram of a conventional device using such a principle.

In the figure, the raw material liquid 1 injected into the mother liquor container 2 by the pump 3 naturally drops into the cooling cylinder 4.

The raw material liquid in the cooling cylinder 4 enters the jacket 6 on the outer periphery of the cylinder from the inflow port 7 and is cooled by the cooling medium 9 discharged from the outflow port 8 to be frozen and become ice crystals 26.

The ice crystals 26 are pulled downward in the cylinder by the pulling body 23, and are pressed into the pressure cylinder 13 having a tapered hole with a narrowed lower portion.

The surface of the ice crystals 26 is heated by the cooling medium 18 (having a higher temperature than the cooling medium 9) that enters the jacket 15 provided in the pressurizing cylinder 13 through the inflow port 16 and is discharged through the outflow port 17.
The surface hardness of the ice crystals 26 is slightly softened, and the ice crystals 26 are pressed more.

By this pressurization, the solute portion having a higher concentration in the ice crystal 26 is separated from the ice crystal 26 and moved to the portion having a lower pressure in the ice crystal, that is, to the upper portion, and the concentrated liquid is discharged from the discharge pipe 20 via the pocket 19. Spill as 27.

However, in the above apparatus, the inner cylinder 5 of the cooling cylinder 4 that allows the raw material liquid 1 to pass while being frozen has a vertically long structure with a uniform inner diameter, and the cooling jacket 6 is provided so as to surround the inner cylinder 5. As a result, the portion in the vicinity of the wall surface of the inner cylinder in the raw material liquid, which has a lower solute concentration, freezes faster.

As a result, the ice hardness of the entire ice crystal 26 becomes uneven, and the ice hardness is lower near the traction body 23 and the solute concentration is higher than that of the peripheral portion.

The ice crystals 26 generated in this way are towed by the tow body 23 and pressed.
When pressed into 13 and pressurized, the ice crystals near the traction body 23, which has a high solute concentration and low freezing hardness, will melt more quickly, and the melted liquid with a high solute concentration will leak into the tank 22. .

[Object of the Present Invention] In view of the above, in the present invention, when a raw material solution containing a solute is frozen in a cooling cylinder to generate ice crystals, the ice crystals are made uniform in ice hardness distribution and the ice crystals are made uniform. In order to evenly distribute the solute concentration in the inside of the pressurizing cylinder, the melting of the ice crystals that are pressed into the pressurizing cylinder proceeds equally throughout the ice crystals, and the solute concentration is made uniform so that a high concentrated solution can be obtained. A freeze concentration device can be provided.

[Means for Solving the Problems] In order to solve the above problems, a pressurization type freeze concentration apparatus of the present invention has a tapered taper hole in a lower portion of a vertical cooling cylinder having a mother liquor container in an upper portion. A pressurizing cylinder is connected through a heat insulating cylinder, a discharge pipe for collecting a concentrated liquid is connected to the upper part of the tapered hole, and an endless tensile wire that pulls ice crystals frozen in the cooling cylinder is connected to the mother liquor. A structure in which a container, a cylinder, a heat insulating cylinder, and a pressurizing cylinder are provided so as to be circulated downward from the upper portion, and the compressed air delivery pipe has an open end in the mother liquor in the cooling cylinder. There is.

[Operation] When the raw material liquid supplied from the mother liquor container is frozen in the cooling cylinder by cooling, compressed air is supplied to the frozen raw material liquid by the compressed air delivery pipe. By supplying this compressed air, innumerable bubbles are generated in the mother liquor, the mother liquor is agitated by the bubbles, and the mother liquor in the cylinder before freezing has a uniform concentration distribution.

Therefore, the ice crystals frozen in the cylinder have a uniform concentration distribution, and the solute separated from the ice crystals by pressing with the pressurizing cylinder becomes uniform, and the concentration of the solute is uniform. A concentrate is obtained.

[Embodiment] An embodiment of the present invention will be described in detail below with reference to FIG.
The same components as those in the conventional example are designated by the same reference numerals.

FIG. 1 is a longitudinal cross-sectional system diagram of the present embodiment. In FIG. 1, there is a mother liquor container 2 for temporarily storing a raw material liquid 1 which is a solution in which a solute such as fruit juice is dissolved. The raw material liquid 1 is supplied from a pump 3. Further, a vertical cooling cylinder 4 is connected to the lower portion of the container 2, and a jacket 6 is provided so as to surround the inner cylinder 5 of the cylinder 4. The cooling medium 9 is injected into the jacket 6 by a pump (not shown), and the cooling medium 9 passing through the jacket 6 is discharged from the outflow port 8.

A ring-shaped heat insulator 11 having an inner diameter equal to that of the inner cylinder 5 of the cylinder 4 is connected to the flange 10 formed in the lower portion of the cooling cylinder 4. Further, below the heat insulator 11 is an upper portion of the pressure cylinder 13. The flange 12 provided in the is connected.

The inner cylinder 14 of the pressure cylinder 13 has a tapered taper hole, and a jacket 15 is provided so as to surround the inner cylinder 14. This jacket 15 has an inlet 16 at the bottom.
However, there are outlets 17 at the top, and this inlet
The second cooling medium 18 is injected from a 16 by a pump (not shown), and the medium 18 passing through the jacket 15 is discharged from the outlet 17
It is designed to be discharged more.

In addition, the upper end of the pressurizing inner cylinder 14 has a recess pocket for storing liquid.
19 is provided, and a liquid discharge pipe 20 is provided in this pocket 19.
Is connected.

Further, a tank 22 for receiving treated ice crystals is connected to the lower flange 21 of the pressure cylinder 13.

An endless chain 23, which is a tensile wire for pulling ice crystals, is provided in the cooling cylinder 4, the heat insulating body 11 and the pressurizing cylinder 13 so as to pass through the central axis of the cooling cylinder 4 in the vertical direction. The chain 23 is designed to be lowered and fed by a driving device (not shown).

Further, a compressed air supply pipe 24 is inserted into the upper part of the inner cylinder 5 of the cooling cylinder 4 from above the mother liquor container 2, and the air supply pipe 24 is connected to a compressor (not shown) to provide compressed air. 25 is ejected into the inner cylinder 5.

Next, each function will be described in detail below.

The raw material liquid 1 poured into the container 2 by the pump 3 is temporarily stored in the container 2 and drops into the inner cylinder 5 of the cooling cylinder 4. The cooling medium 9 circulating in the jacket 6 in the cooling cylinder 4 has a cooling temperature of about -20 ° C., and the raw material liquid 1 is cooled by this cooling medium and frozen to form ice crystals 26. .

Further, the raw material liquid 1 is agitated by the compressed air ejected from the air delivery pipe 24 inserted in the upper portion of the inner cylinder 5 in which the ice crystals 26 and the liquid of the raw material liquid 1 are mixed, so that the solute concentration distribution is uniform in ice. Crystal 26 is formed.

Since the ice crystals 26 are frozen in the chain 23, they are attracted by the chain 23 and pressed into the pressure cylinder 13.

Since the temperature of the second cooling solvent body 18 circulating in the jacket 15 of the pressurizing cylinder 13 is 2 to 3 ° C., the outer peripheral surface of the ice crystal 26 is slightly softened and is pressurized by the taper hole of the inner cylinder 14. This lowers the freezing point, so that the solute in the ice crystals is separated and moves as the concentrated liquid 27 to the upper part of the tapered hole where the pressing force is small.

The concentrated liquid 27 is discharged to a product storage tank (not shown) through the discharge pipe 20, and the residual ice crystals 26 from which the concentrated liquid 27 is separated fall into the tank 22 below the pressurizing cylinder 13.

In this way, the compressed air is blown into the raw material liquid 1 before it becomes ice crystals 26, whereby the mother liquor is agitated and freezes, so that the solute concentration distribution in the ice crystals 26 becomes uniform and the ice crystals 26 become frozen. The hardness distribution is also uniform. Therefore, the ice crystals pressurized in the pressurizing cylinder 13 satisfactorily semi-melt and the concentrated liquid 27 containing a large amount of solute can be efficiently separated.

[Effects of the Invention] As described above, according to the present invention, the raw material liquid before freezing is agitated by compressed air to have a uniform concentration distribution, and ice crystals having a uniform concentration are generated.

Therefore, the concentration of the solute separated by the pressurization is not uneven, and a concentrated liquid having a uniform concentration can be obtained.

[Brief description of drawings]

FIG. 1 is a system sectional view showing an embodiment of the present invention, and FIG. 2 is a system sectional view of a conventional example. In the figure 1 ... Raw material liquid, 2 ... Mother liquor container 3 ... Pump, 4 ... Cooling cylinder 5 ... Inner cylinder, 6 ... Jacket 7 ... Inlet, 8 ... Outlet 9 ... Cooling Medium, 10 …… Flange 11 …… Insulation cylinder, 12 …… Flange 13 …… Pressure cylinder, 14 …… Pressure inner cylinder 15 …… Jacket, 16 …… Inflow port 17 …… Outflow port, 18… … Second cooling medium 19 …… Recessed pocket, 20 …… Discharge pipe 21 …… Lower cylinder, 22 …… Bath 23 …… Chain, 24 …… Compressed air delivery pipe 25 …… Compressed air, 26 …… Ice Crystal 27 ... Concentrated liquid

Claims (1)

[Claims] 1. A vertical cooling cylinder having a mother liquor container on an upper part thereof is connected to a lower part of a pressurizing cylinder having a tapered taper hole through a heat insulating cylinder, and an upper part of the tapered hole for collecting a concentrated liquid is collected. An endless tensile wire that connects an exhaust pipe and draws ice crystals frozen in the cooling cylinder is circulated downward from the upper part through the mother liquor container, the cylinder, the heat insulating cylinder, and the pressurizing cylinder. Pressurized freezing and concentrating device in which the tip of the compressed air delivery pipe connected to the compressor is opened into the upper part of the cooling cylinder.