JPH067883B2 - Pressurized freeze concentrator - Google Patents

Description

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

[Prior Art] A solution containing a solute and a solvent (water) is once frozen to form an ice crystal, and the ice crystal is pressurized to separate a solution having a high solute concentration from the ice crystal to produce a concentrated solution. A so-called pressurization type freeze concentration device has been known for some time.

These devices utilize the physical phenomenon that the freezing point (freezing point) of a solution changes depending on the solute concentration with respect to the solvent (water) and the pressure applied to the solution.

For example, in the case of an aqueous solution, the freezing point is lowered by pressurization, and the freezing point is also lowered due to the high concentration of solute contained in the aqueous solution.

According to FIG. 6, a system diagram of the former apparatus is shown. The raw material liquid 32 injected into the mother liquor container 31 by the pump P naturally drops into the cooling cylinder 33.

Then, the raw material liquid 32 is cooled and frozen by the cooling medium 39 which enters from the inlet 34a in the cooling cylinder 33, exits from the inlet 34b and circulates in the jacket 34, and is frozen to form ice crystals 36.
Becomes

The ice crystals 36 are pulled downward by the towing body 37, and the heat insulating portion 35
After that, the lower part is press-fitted into a pressurizing cylinder 38 having a tapered hole with a narrowed portion, and is pressurized.

Further, the inlet 41a of the jacket 41 provided in the pressurizing cylinder 38
Ice crystal 36 by the cooling medium 40 having a temperature slightly higher than that of the cooling medium 39 which is circulated from the inlet 41b and discharged from the inlet 41b.
Is heated to lower the freeze hardness. This gives ice crystals 36
The concentrated liquid 44 having a higher solute concentration is melted and separated, and flows out to the discharge pipe 43 through the pocket 42.

However, in the above device, the cooling cylinder 33
The inner tube through which the raw material liquid 32 passes has an elongated structure with a uniform tube inner diameter, and since the cooling jacket 34 is provided so as to surround it, the freezing hardness of the ice crystals 36 in the longitudinal direction of the tube. It becomes uneven. Therefore, the descending speed of the ice crystals 36 having a high freezing hardness that is press-fitted into the pressurizing cylinder 38 is rapidly reduced, and the semi-melting of the ice crystals 36 does not proceed sufficiently by the heating by the cooling medium 40 of the jacket 41. , The concentrated liquid will not be effectively separated from the ice crystals 36. On the contrary, if the freezing hardness of the ice crystals 36 is too low, sufficient external pressure cannot be applied by the pressurizing cylinder 38, and the semi-melting of the ice crystals 36 progresses too much due to the heating by the cooling medium 40, and the concentrated liquid becomes a tank 45. Processing capacity will be significantly reduced due to liquid leakage.

[Object of the Present Invention] According to the present invention, the freezing hardness of the ice crystals purified by freezing the raw material liquid in the cooling cylinder is always equalized in the longitudinal direction, and the ice crystals are smoothly aged in the freezing zone. By making the solute concentration distribution of the ice crystal uniform, the internal pressure rise of the ice crystals pressed into the pressurizing cylinder is always constant, and when the ice crystals are half melted by heating in the pressurizing cylinder, the excess Thus, it is possible to provide a pressurization type freeze concentration device that prevents the concentrated liquid from leaking due to excessive melting.

[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 hole in which a lower part is narrowed in a lower part of a vertical cooling cylinder having a mother liquor container in an upper part. A pressure cylinder having a heat-insulating cylinder is connected, a discharge pipe for collecting the concentrated liquid is connected to the upper portion of the tapered hole, and an endless tensile wire for pulling ice crystals is provided in the mother liquor container, in the cylinder, and heat-insulated. A device that is fed through the inside of the cylinder and the inside of the pressurizing cylinder from above to below, in which the cooling cylinder has multiple stages, and the cross-sectional area of each cooling cylinder inner tube is uniform and the inner wall surface meanders. Moreover, the cooling temperature of each cooling cylinder is different.

[Operation] When ice crystals frozen in the first cooling cylinder are pulled downward by the tensile wire, the ice crystals meander in the cooling cylinder to cause various horizontal bias pressures. Join the ice crystals from the direction. As a result, the ice crystals in the ice crystals are agitated and the crystallization action is enhanced, so that the ice hardness of the ice crystals is kept uniform, and when the solvent freezes, the solute is efficiently included to form ice. The solute concentration distribution also becomes uniform. The ice crystals are well heated in the pressurizing cylinder to cause semi-melting and accelerate the separating action of the concentrated liquid.

[Examples] Examples of the present invention will be described below in detail with reference to Figs.

FIG. 1 is a system diagram of the first embodiment, in which a first cooling cylinder 4 is provided under a mother liquor container 2 for temporarily storing a raw material liquid 3 which is an aqueous solution containing a solute. Is provided. The inner pipe of the first cooling cylinder 4 has a multi-stage structure, and the upper inner pipe 4a has a tapered hole that widens toward the end. Further, the middle inner pipe 4b connected to the upper inner pipe 4a without steps. Is a vertical cylinder structure with a uniform inner diameter. A lower inner tube 4c is connected below the middle inner tube 4b with its tube central axis 4e inclined below the central axis 4f of the entire apparatus.

Further, the first cooling cylinder 4 is provided with a jacket 5 so as to surround the inner pipes 4a, 4b, 4c, and
The cooling medium 6 from 5a is a jacket 5 by a pump (not shown).
It is injected to circulate inside. Further, the cooling medium 6 circulating in the jacket 5 is discharged from the outflow port 5b.

A second cooling cylinder 8 is provided below the first cooling cylinder 4.
However, the lower flange 4d of the cooling cylinder 4 and the upper flange 8b of the second cooling cylinder 8 are connected with the heat insulating cylinder 7 interposed therebetween. Inner tube 8a in the second cooling cylinder 8
The inner diameter of is the same as the inner diameter of the heat insulating cylinder 7, and the inner tube 8a
The center axis 8d of the cylinder is lower than the center axis 4f.
It is inclined in the opposite direction to 4c. Further, a jacket 9 is provided in the second cooling cylinder 8 so as to surround the inner pipe 8a, and a cooling medium 10 is injected from an inflow port 9a so as to circulate in the jacket 9 by a pump (not shown). Has been done. Further, the cooling medium 10 circulating in the jacket 9 is discharged from the outflow port 9b.

Further, a third cooling cylinder 12 is provided below the second cooling cylinder 8, and the lower flange 8c of the cooling cylinder 8 and the upper flange 12c of the third cooling cylinder 12 form a heat insulating tubular body.
It is connected across 11. The upper inner tube 12a of the cooling cylinder 12 has an inner tube central axis 12e inclined from the central axis 4f in a direction opposite to the inner tube 8a of the second cooling cylinder 8. The inner tube central axis 12f of the lower inner tube 12b of the third cooling cylinder 12 is collinear with the central axis 4f.

A jacket 13 is provided so as to surround the inner pipes 12a and 12b, and a cooling medium 14 is injected from an inflow port 13a so as to circulate in the jacket 13 by a pump (not shown). Further, the cooling medium circulated in the jacket 13
14 is discharged from the outlet 13b.

A pressurizing cylinder 15 is connected to the lower part of the third cooling cylinder 12 with its upper flange 15a and lower flange 12d of the third cooling cylinder 12 sandwiching a heat insulating cylinder 18.

The pressurizing cylinder 15 has a tapered hole in which the lower part of the inner wall surface is narrowed, and further, a recess pocket for storing a liquid is provided at the upper end of the inner wall.
19 are provided, and the discharge pipe 20 is provided in this pocket 19.
Are connected.

Further, the pressurizing cylinder 15 is provided with a jacket 16 which surrounds the pressurizing cylinder 15, a cooling medium 17 is injected from an inlet 16a of the jacket 16 by a pump (not shown), and further the cooling medium circulated in the jacket 16 is cooled. The medium 17 is the outlet
Emitted from 16b. Furthermore, below the pressurizing cylinder 15, a tank 21 for receiving the treated ice crystals is provided.

As described above, each inner pipe from the middle inner pipe 4b of the first cooling cylinder 4 to the lower inner pipe 12b of the third cooling cylinder 12 is
It has the same inner diameter and has a structure in which a path meandering the inner wall surface is formed.

Further, on the central axis of the device, a pulling tensile force that vertically penetrates the mother liquor container 2, each part of the first, second and third cooling cylinders and each inner pipe of the pressurizing cylinder 15 is provided. An endless chain 24, which is a wire rod, is fed down by a motor (not shown). Furthermore, a pump 1 for injecting the raw material liquid 3 into the container 2 is provided above the container 2.

Next, the processing functions of each part of the present apparatus will be described in detail below.

The raw material liquid 3 is poured into the container 2 by the pump 1, and the raw material liquid 3
Descends from the container 2 to the upper inner pipe 4a of the first cooling cylinder 4.

Then, the raw material liquid 3 is added to the cooling medium 6 having a temperature of about −20 ° C. circulating in the jacket 5 of the first cooling cylinder 4.
Is cooled and freezes to form ice crystals 23.

Since this ice crystal 23 is frozen around the chain 24, the chain 24
The inner pipes below the middle inner pipe 4b are lowered by being pulled by. At the initial stage of cooling, the ice crystals 23 are in a semi-crystalline state in which microcrystals that are solute-containing ice and an aqueous solution are mixed, but when the ice crystals 23 in this semi-crystalline state pass through the inclined lower inner pipe 4c. In addition, the inclination causes the ice crystals 23 to be deflected. As a result, the fine crystals in the ice crystals 23 are moved and stirred, and combined with other aqueous solution to enhance the crystallization effect. After this,
The ice crystals 23 pass through the heat insulating cylinder 7 and are pulled by the chain 24 to the second cooling cylinder 8. Since the inner pipe 8a of the cooling cylinder 8 has an inclination direction different from that of the lower inner pipe 4c, the ice crystals 23 are deflected in a new direction to stir the fine crystals to cause crystallization. Further enhanced. Also, the first
Since the temperature of the cooling medium is higher than that of the cooling cylinder 4 at around −15 ° C., the freezing speed is suppressed to a low level, so that the ice crystals sufficiently contain the solute.

The ice crystal 23 thus aged in the crystal state is further pulled by the chain 24 and introduced into the third cooling cylinder 12 through the heat insulating cylinder 11. Here, since the cooling medium 14 circulating in the jacket 13 is cooled at around -8 ° C,
Also, unlike the second cooling cylinder, the ice crystals 23 can lower their freezing hardness. After that, the ice crystals 23 are pulled by the pressure cylinder 15 via the heat insulating cylinder 18. This pressure cylinder
The cooling medium 17 circulating in the jacket 16 of 15 is 2 to 3
Since the temperature is ℃, the ice crystals 23 are heated and semi-melted.
Further, the ice crystal 23, which is pulled by the chain 24 from above by the tapered hole of the pressurizing cylinder 15, has a higher ice crystal internal pressure in the lower part of the cylinder 15 and a lower ice crystal internal pressure in the upper part.

However, the freezing point of the ice crystals 23 decreases as the pressure increases and the solute concentration increases, so that the ice crystals 23 passing through the pressurizing cylinder 15 move downward, and the concentrated liquid 22 with a high solute concentration increases. Are sequentially melted and separated from the ice crystals 23, and are squeezed out to the upper side where the pressure is low and flow into the pocket 19.

The concentrated liquid 22 that has flowed into the pocket 19 flows out to a tank (not shown) through the discharge pipe 20 and is stored therein.

Further, the residual ice crystals 23 having a low solute concentration that have passed through the pressure cylinder 15 fall into the tank 21.

Next, FIG. 2 shows a second embodiment.

In this device, the same parts as those in the first embodiment are designated by the same reference numerals in FIG.

In FIG. 2, the inner pipe 4g in the first cooling cylinder 4 always has a uniform inner diameter, and forms a meandering path having an eccentric distance according to the vertical position from the central axis 4f of the apparatus. is doing. Similarly to the inner pipe 4g, the inner pipe 8e of the second cooling cylinder 8 and the inner pipe 12g of the third cooling cylinder 12 are always uniform in inner diameter and have a meandering path structure. Other structures and functions are the same as those in the first embodiment.

Further, a third embodiment is shown in FIGS. In this apparatus, the same components as those in the first embodiment are designated by the same reference numerals in FIG. A top view of the inner pipe 4h of the first cooling cylinder 4 in FIG. 3 is shown in FIG. 4, and a schematic view of the inner pipe 4h with a part cut off is shown in FIG.

The inlet portion 4i of the inner pipe 4h has an elliptical shape having a major axis in the left-right direction and a minor axis in the front-rear direction on the fourth drawing. The inner shape of the inner pipe 4h is such that the minor diameter at the inlet portion 4i extends to become the major diameter from the inlet portion 4i toward the central portion 4j, and the major diameter at the inlet portion 4i decreases and becomes shorter. It changes into an elliptical shape with a diameter.

Therefore, the central portion 4j of the inner pipe 4h has an elliptical shape having a short diameter in the left-right direction and a long diameter in the front-rear direction in the drawing. Further, the inner tube 4h is deformed again at the outlet 4k so as to have an elliptical shape with the major axis in the left-right direction and the minor axis in the front-rear direction in FIG. As described above, the inner tube 4h changes its inner shape by changing the length of the major axis and the minor axis depending on the vertical position, and moreover, the horizontal cross section of this inner tube has an elliptical shape that is always uniform. It is a modified version. Further, the inner pipe 8f of the second cooling cylinder 8
Also, the inner pipe 12h of the third cooling cylinder 12 has the same structure as the inner pipe 4h. Other structures and functions are the same as those in the first embodiment.

As described above, the inner pipe cross-sectional areas of the first, second, and third cooling cylinders are always uniform, and the inner wall surface of the cooling cylinder has undulations. The ice crystals 23 can be subjected to a deflection pressure on the horizontal plane to increase the ice crystal density and make the solute concentration in the ice crystals 23 uniform.

[Effects of the Invention] As described above, according to the present invention, the structure of the cooling cylinder inner tube that cools the raw material liquid into ice crystals passes through the inner tube by causing the inner wall surface to meander. Since the deflection pressure in the horizontal direction was applied to the ice crystals, the microcrystals in the ice crystals were agitated to allow smooth ripening of the ice crystals. As a result, the freezing hardness of the whole ice crystal is always made uniform,
The solute concentration distribution can always be made uniform. In addition, the rise in the internal pressure of the ice crystals pressed into the pressurizing cylinder is constant because the ice hardness is always uniform, and the warmed ice crystals are well melted. It is possible to quickly and satisfactorily separate and purify from ice crystals without leaking.

[Brief description of drawings]

1 is a system sectional view showing a first embodiment of the present invention, FIG. 2 is a system sectional view showing a second embodiment of the present invention, and FIG. 3 is a system sectional view showing a third embodiment of the present invention. FIG. 4 is a top view of the cooling cylinder inner pipe in the third embodiment of the present invention, FIG. 5 is an external view of the cooling cylinder inner pipe in the third embodiment of the present invention, and FIG. 6 is a conventional example. FIG. In the figure 1 ... Pump 2 ... Container 3 ... Raw material liquid 4 ... First cooling cylinder 4a ... Upper inner pipe 4b ... Middle inner pipe 4c ... Lower inner pipe 4d, 8b, 8c, 12c, 12d , 15a ・ ・ Flange 4g, 4h ・ ・ Inner tube 4f ・ ・ Center axis 5,9,13,16 ・ ・ Jacket 5a, 9a, 13a, 16a ・ ・ Inlet port 5b, 9b, 13b, 16b ・ ・ Outlet port 6 , 10,14,17 ・ ・ Cooling medium 7,11,18 ・ ・ Adiabatic cylinder 8 ・ ・ Second cooling cylinder 8a, 8e, 8f ・ ・ Inner tube 12 ・ ・ Third cooling cylinder 15 ・ ・ Addition Pressure cylinder 19 ・ ・ Recessed pocket 20 ・ ・ Drain pipe 21 ・ ・ Tank 22 ・ ・ Dense liquid 23 ・ ・ Ice crystals 24 ・ ・ Chain

Claims (1)

[Claims] 1. A vertical cooling cylinder having a mother liquor container in the upper part thereof is connected to a lower part of a pressurizing cylinder having a tapered hole narrowed through a heat insulating cylinder, and the concentrated liquid is collected in the upper part of the tapered hole. A device for connecting an exhaust pipe for cooling and feeding endless tensile wire for pulling ice crystals through the mother liquor container, the cylinder, the heat insulating cylinder, and the pressurizing cylinder from above to below. A pressurization type freeze-concentrating device characterized in that the number of cylinders is multi-staged, the cross-sectional area of each cooling cylinder inner tube is uniform, and the inner wall surface is meandering, and the cooling temperature of each cooling cylinder is different.