JPH064121B2 - Pressurized freeze concentrator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pressurization type freeze concentration apparatus for producing various kinds of beverages, chemicals, and other concentrated solutions.

[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.

As shown in the system diagram of the previous apparatus according to FIG. 4, 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 that enters from the inflow port 34a of the jacket 34 in the cooling cylinder 33, exits from the outflow port 34b and circulates, and becomes ice crystals 36.

This ice crystal 36 is pulled downward by the pulling body 37, passes through the heat insulating portion 35, and is pressed into a pressurizing cylinder 38 having a tapered hole with a narrowed lower 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 cooling medium 39 which is circulated from the cooling medium 39 which is circulated through the cooling medium 36.
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 apparatus, if the temperature of the cooling medium 40 is increased for the purpose of speeding up the speed of the ice crystals 36 passing through the pressurizing cylinder 38 and increasing the processing speed, the thermal conductivity of the ice crystals themselves becomes poor. Due to the difference in the residence time distribution of the ice crystals in the first-order phase transition state in the pressure cylinder, the ice crystals in the vicinity of the traction body 37 melt faster than in the vicinity of the inner wall surface of the pressure cylinder 38. The concentrated liquid 44 will leak into the receiving tank 45. Conversely, when the temperature of the cooling medium 40 is lowered, the melting of the ice crystals 36 does not proceed sufficiently, the pressure of the ice crystals 36 increases, the speed of the ice crystals 36 passing through the pressurizing cylinder 38 decreases, and the processing capacity is reduced. It will be significantly reduced.

[Object of the Invention] According to the present invention, the melting degree distribution of ice crystals passing through the pressurizing cylinder is made uniform in the radial direction of the pressurizing cylinder to prevent leakage of the concentrated liquid due to melting of the ice crystals near the towing body. , It was made possible to provide a pressurization type freeze concentrator with a high processing capacity that effectively produces a concentrated liquid without reducing the ice crystal pulling speed of the pulling body.

[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. The device is a device that is fed through the inside of the cylinder and the inside of the pressure cylinder from above to below, and has a structure in which an appropriate number of inwardly projecting heat radiation blades are provided on the inner wall of the pressure cylinder.

[Operation] The ice crystals frozen in the cooling cylinder are pulled downward by the tensile wire and pressed into the pressurizing cylinder. The heat radiating blade provided on the inner wall surface of the pressure cylinder uniformly and half-melts the ice crystals, and further moves and presses downward.
As a result, the high-concentration solute liquid in the ice crystals is squeezed upward from below in the pressurizing cylinder and flows out from the discharge pipe as a concentrated liquid.

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

FIG. 1 is a system diagram of this apparatus, in which a cooling cylinder 4 is provided below a mother liquor container 2 for temporarily storing a raw material liquid 3 which is an aqueous solution containing a solute. There is. A jacket 5 is provided on the cooling cylinder 4 so as to surround it in the circumferential direction, and a cooling medium 7 is introduced into the jacket 5 through an inflow port 5a by a pump (not shown). The circulating cooling medium 7 is discharged from the outflow port 5b.

A pressurizing cylinder 12 is connected to the lower portion of the cooling cylinder 4 such that the heat insulating cylinder 10 is sandwiched between the upper flange 11 and the lower flange 9 of the cooling cylinder 4.

As shown in FIGS. 2 and 3, the pressurizing cylinder 12 has a tapered hole in which the lower part of the inner wall surface is narrowed, and the inner wall surface has blades 14a to 14h projecting toward the center at 45 ° intervals. Is provided. Each of these blades has a double edge on top of it.
19, and the inward surface 20 of each blade is vertical. Further, the width of protrusion of the blades 14a, 14c, 14e, and 14g from the inner wall surface of the pressure cylinder 12 is shorter than the width of protrusion of the blades 14b, 14d, 14f, and 14h on both sides thereof. Has become. The gap 21 surrounded by the inward surface 20 of each of these blades does not hinder the movement of the chain 8 which is an endless traction body that vertically penetrates the center of the apparatus. The chain 8 is reciprocated from above by a motor (not shown) at a speed of about 20 mm / min.

A recessed pocket 15 for storing a liquid is provided in the upper part of the inner wall of the pressurizing cylinder 12, and a drain pipe 16 is provided in this pocket 15.
Are connected.

The pressure cylinder 12 also has a jacket that surrounds it in the circumferential direction.
13 is built in, and this jacket 13 has an inlet 13a.
More cooling medium 17 is injected by a pump (not shown),
Further, it circulates in the jacket 13 and is discharged from the outlet 13b. A tank 18 for receiving the treated ice crystals is provided below the pressurizing cylinder 12.

Next, the processing function 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
Freely falls from the container 2 into the cooling cylinder 4.

Since the cooling medium 7 circulating in the jacket 5 of the cooling cylinder 4 is cooled to -30 to -15 ° C, heat energy is taken from the raw material liquid 3 passing through the cooling cylinder 4.

As a result, the raw material liquid 3 freezes in a columnar shape around the chains 8 to form ice crystals 6.

The ice crystals 6 are pulled by the descending chain 8, pass through the heat insulating cylinder 10, and are pressed into the pressure cylinder 12.

The ice crystal 6 passing through the pressurizing cylinder 12 is heated by the cooling medium 17 circulating in the jacket 13 of the pressurizing cylinder 12 and having a temperature of 2 to 5 ° C., so that the freezing hardness of the ice crystal 6 is lowered.

Further, since the blade 14 provided on the inner surface of the pressurizing cylinder 12 quickly conducts heat in the radial direction of the ice crystal, the entire ice crystal 6 in the pressurizing cylinder 12 is uniformly heated and the ice crystal 6 is uniform. Moreover, it melts to have low freezing hardness.

Furthermore, the ice crystal 6 pulled by the chain 8 from above by the tapered hole of the pressurizing cylinder 12 and press-fitted has a higher ice crystal internal pressure toward the lower part,
The ice crystal inner pressure is lower toward the top.

By the way, the freezing point of the ice crystals 6 decreases as the pressure increases or the solute concentration increases, so that as the ice crystals 6 passing through the pressurizing cylinder 12 move downward, the solution with high solute concentration becomes 6 is melted and separated sequentially, and is squeezed out to the upper side where the pressure is low and flows into the pocket 15.

The concentrated liquid that has flowed into the pocket 15 flows out to a tank (not shown) through the discharge pipe 16 and is stored therein.

Further, the residual ice crystals 6 having a low solute concentration that have passed through the pressurizing cylinder 12 fall into the tank 18.

The plate thickness of the blade 14 is not particularly limited,
Any thickness may be used as long as it does not extremely hinder the descending speed of the ice crystals 6 passing through the pressurizing cylinder 12 and that it effectively promotes heat conduction.

For example, when the pressure cylinder 12 has an inlet diameter of 54 mm and an outlet diameter of 40 mm, the blade 14 has a plate thickness of about 10 to 12 mm. Further, on the blade plate surface, in order to further increase the thermal conductivity, it may have a structure having a large number of small cutouts or protrusions in the vertical direction, and the outer shape of the blade 14 is not a trapezoid like the above example but a semi-shape. It may be oval or the like.

Further, the number of the blades 14 is not limited to eight as in the above example, and may be one in which a large number of blades are arranged in a vertical direction in a column or a plurality of blades are arranged in a circumferential direction. Good.

Since the blade 14 is provided on the inner wall of the pressurizing cylinder 12 in this manner, the ice crystals 6 passing through the pressurizing cylinder 12 can be uniformly and half-melted so that only the ice crystals near the chains 8 are melted first. In addition to preventing the above, the descending speed of the ice crystals 6 can be increased, and the processing speed of the concentrated liquid manufacturing process can be improved.

[Advantages of the Invention] As described above, according to the present invention, the blade for increasing the heat transfer efficiency in the radial direction is provided on the inner wall surface of the pressurizing cylinder, so that the ice crystals in the pressurizing cylinder can be made uniform. It becomes possible to melt quickly, and it is possible to prevent melt water from leaking first only in the vicinity of the traction chain at the center of the ice crystal, and to increase the processing speed of the concentrated liquid separation.

[Brief description of drawings]

 FIG. 1 is a system sectional view showing an embodiment of the present invention, FIG. 2 is a vertical sectional view of a pressurizing cylinder of the present invention, and FIG. 3 is a top view of the pressurizing cylinder. FIG. 4 is a diagram showing a conventional example. In the figure 1 ・ ・ Pump 2 ・ ・ Container 3 ・ ・ Material liquid 4 ・ ・ Cylinder for cooling 5 ・ ・ Jacket, 5a ・ ・ Inlet 5b ・ ・ Outlet 6 ・ ・ Ice crystal 7 ・ ・ Cooling medium・ ・ ・ Chain 9 ・ ・ Flange, 10 ・ ・ Insulating cylinder 11 ・ ・ Flange, 12 ・ ・ Pressurizing cylinder 13 ・ ・ Jacket, 13a ・ ・ Inlet 13b ・ ・ Outlet, 14 ・ ・ Blade 15 ・ ・Pocket, 16 ... Ejection pipe 17 ... Cooling medium, 18 ... Tank 19, double-edged, 20 ... Inward surface 21 ...

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. Is connected to a discharge pipe for the purpose of feeding an 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. Pressurized freeze concentrator with a proper number of inward protruding heat dissipation blades on the inner wall of the cylinder.