JP4505312B2 - Melting separator - Google Patents

Description

The present invention relates to a thawing separation devices, and particularly those high concentrations enriched foods solutions concerning rows of UToru solution separating apparatus.

  Evaporation concentration, membrane concentration, and freeze concentration methods are used to concentrate food solutions. Of these, the evaporative concentration method is not preferred due to the wide range of applicable solutions, but due to the changes in food components due to heating, and the membrane concentration method requires a replacement of the membrane, although the concentration energy is small, but it is not manufactured. We have problems such as cost increase. In view of this, conventionally, concentration by freeze concentration has been generally carried out as a solution for foods so that there is little change or loss of the solute due to the concentration operation and there is no concern about microbial growth during the concentration operation.

  Here, freeze concentration is a technology that achieves concentration by freezing only the water in the aqueous solution and separating the generated ice crystals from the unfrozen concentrate. The concentrated solution is freeze-concentrated to the concentration limit, and the treated liquid concentrated to the concentration limit is separated from the ice.

  From the viewpoint of separation of the processed liquid and the ice, freeze concentration is divided into a batch type in which a separation operation is performed after a single concentration process up to the concentration limit, and a continuous type in which separation is continuously performed in the concentration process. It is divided roughly into. From the viewpoint of ice generation / growth mode, it is roughly divided into a forward freezing method in which ice adheres and grows on the cooling heat transfer surface and a suspension crystal method in which granular ice is generated and grown in the solution.

  In particular, as an example of the forward freezing method, there is a freeze concentration (freeze separation) apparatus proposed by the present applicant in Patent Document 1. This freeze concentrator is provided with a cooling coil in the crystallization tank, a water sprayer above it, a water storage part below the cooling coil, and water to be treated from the water sprayer to the cooling coil. The liquid to be treated is sequentially dropped to the lower side while being in contact with each cooling coil, and the liquid to be treated is cooled and frozen in the process of flowing down while being in contact with the cooling coil in a liquid film state. In addition, the liquid to be treated that has reached the water storage unit without being frozen is circulated and supplied to the sprinkler and cooled again. By repeating this, a predetermined amount of the stock solution can be concentrated to the concentration limit (about 10 times). The treated liquid that has reached the concentration limit is discharged out of the system. Hereinafter, this technique is referred to as falling film type freeze concentration.

Patent Document 2 also falls within the category of the forward freezing method. This prior art is intended to solve the solute uptake into ice crystals due to the excessive supercooling degree when ice is formed on the surface of the cooling body. By generating pure ice in advance, excessive supercooling of the treatment liquid in the vicinity of the cooling body is suppressed.
Japanese Patent Laid-Open No. 2001-47034 (pages 2 and 3 and FIG. 1) JP 10-54629 A

  However, in the conventional freeze concentration, when it is assumed that the desired concentration and separation performance is maintained, there is a problem that the limit of the concentration ratio is about 10 times. That is, in the conventional freeze concentration, the limit of the concentration ratio in one concentration (concentrating the stock solution to a predetermined concentration limit) is about 10 times. On the other hand, it is conceivable to further increase the concentration ratio by repeating the freeze concentration process using the treated solution as a stock solution again. However, as is well known, freeze concentration increases the concentration of the treatment solution at the start of concentration. However, since the concentration and separation performance deteriorates, the processed liquid concentrated to about 10 times has a problem that the concentration and separation efficiency is remarkably reduced due to its high concentration. The freeze concentration method is a low-temperature and energy-saving concentration method, which is effective for a solution having a raw water concentration of less than 1% (low concentration water), but is not suitable for high concentration concentration.

  Accordingly, a main object of the present invention is to provide a melting separation method and a melting separation apparatus using the same, which perform high-concentration concentration simply and efficiently using a known centrifuge.

<Invention of Claim 1 >
The invention described in claim 1 is a thawing / separation device for separating a melt from generated ice obtained by freezing a target solution, the thawing / separation device comprising a centrifuge having a basket, and an inside of the basket. A heater device that feeds heated air to the duct, the heater device comprising a duct, a heater attached to the duct for heating the taken-in air, and a damper for adjusting the air flow rate, at least The melt separation apparatus characterized in that the amount and concentration of the melt to be extracted can be adjusted by controlling the peripheral speed at which the basket rotates, the heating amount of the heater, and the ventilation amount by the damper. is there.

(Function and effect)
At least the amount and concentration of the melt to be extracted can be adjusted by controlling the peripheral speed at which the basket rotates, the heating amount of the heater, and the ventilation amount by the damper.

<Invention of Claim 2 >
The invention according to claim 2 is a thawing / separation device for separating a melt from generated ice obtained by freezing a target solution, wherein the thawing / separation device is a continuous centrifugal separator having a bowl and a screw conveyor. And a heater for heating the bowl surface, and by adjusting at least the peripheral speed at which the bowl rotates and the heating amount of the heater, the amount and concentration of the extracted melt can be adjusted. , A melting and separating apparatus characterized by the above.

(Function and effect)
By controlling at least the peripheral speed at which the bowl rotates and the heating amount of the heater, the amount and concentration of the extracted melt can be adjusted. Moreover, since it is a continuous type, it is possible to continuously extract the melt at a desired concentration.

  According to the present invention, there are advantages that a high concentration concentration can be easily and efficiently performed using a known centrifuge.

Embodiments of the present invention will be described below.
<Melting separation method>
The melt separation method is a method of separating a solution by slowly melting a frozen solution and separating an initial melt and a late melt. This method applies a phenomenon in which, when a frozen solution is thawed, melting starts from a high-concentration solution with a low melting temperature and a high-concentration solution oozes out from the inside of the ice. As it melts, the juice at the beginning of the melt is thick, gradually thinning as it melts, and the empirical fact that the last ice has almost no taste of water.

  The present inventor confirmed in the following experiment that the high-concentration concentration is more effective by the melt separation method than the freeze concentration method. As shown in FIG. 1, the experimental method is as follows. After 1 L of the target solution is placed in a resin container and sufficiently frozen in a freezer (−15 ° C.), it is melted slowly (about 8 hours) at room temperature (about 20 ° C.). The melted water is divided into 100 mL portions and taken into 10 collection containers (10-stage collection), and the respective concentrations are measured. A NaCl solution was used as the solution, and the test was performed at different concentrations.

  The results of testing with a 3.5% NaCl aqueous solution corresponding to seawater are shown in FIG. On the horizontal axis, the melted water collected in 10 containers is shown in the order of melting for a concentration of 100 mL of melted water. 100 mL at the beginning of melting was 13.0% of the concentration of raw water about 4 times. As the melting progressed, the concentration decreased, and when the melting exceeded 30%, the molten water concentration became thinner than the raw water concentration, and the final molten water was 0.31% of the concentration of about 1/10 of the raw water.

  FIG. 3 shows the results of a melting separation test of 3.5% and 10% NaCl aqueous solutions. The initial concentration of melting has a large difference depending on the raw water concentration, but the difference becomes smaller as the melting proceeds, and the ice concentration at the end of melting is as low as about 0.1% regardless of the raw water concentration. For comparison, the concentration of concentrated water that was freeze-concentrated to 1/10 at a raw water concentration of 3.5% and 10% is indicated by black circles in FIG. Comparing the concentrated water concentrations of freeze concentration and thawing separation, it was shown that the concentration of concentrated water is higher in thawing separation than freeze concentration in the high concentration water with the raw water concentration of 3.5% and 10%.

  From the above, it can be seen that in the case of a high concentration solution (at least about 3.5% or more), the melting separation method has a higher initial concentration of melting and the concentration effect is higher than that of freeze concentration. Since the effect of concentration is noticeable for a solution having a large freezing point depression, the present invention is more effective when used for high concentration concentration of a solution having a large freezing point depression. In the above, an experiment was performed on an aqueous NaCl solution. However, the present invention is not limited to this solution, and the same effect can be obtained with other solutions.

  Then, the present inventor has found an apparatus and a method for performing high concentration concentration simply, at low cost and efficiently using a known centrifugal separator by this melting separation method. Specifically, when separating the melt from the product ice obtained by freezing the target solution, the product ice is heated, the resulting melt is centrifuged, and the melt is reduced from a high concentration stage to a low concentration. Extraction is performed by sequentially shifting over a plurality of stages. In other words, using the fact that melting starts from a high-concentration solution with a low melting temperature, the melt that transitions from the high-concentration stage to the low-concentration stage is recovered in multiple stages. At this time, the melt and ice are separated actively by centrifugation, and a high concentration solution is efficiently separated by gradually heating while applying centrifugal force, and high concentration concentration is simplified. In addition, it can be realized at a low cost. In addition, sedimentation by gravity may be used instead of centrifugation, but centrifugation has better separation performance than gravity separation, and the higher the concentration, the more significant the difference. Those are preferred. Hereinafter, a more specific configuration of the melting and separating apparatus will be described.

<Configuration of batch-type melt separation apparatus>
As shown in FIG. 4, the batch-type melting / separating apparatus according to the present invention includes a centrifuge 1 that separates a melt from generated ice, and a heater device 2 that sends warm air to the centrifuge 1. Yes.

  In this embodiment, the centrifugal separator 1 is a batch type of centrifugal filtration and adopts a basket basket type. The centrifuge 1 can store ice from the top, and the basket 11 that rotates horizontally, the casing 12 that stores the basket 11, and the melt separated from the basket 11 are placed outside the casing 12. And a discharge conduit 13 for discharging. Specifically, a driving force of a motor (not shown) is transmitted to a shaft 14 provided at the lower part inside the casing 12 via a gear and a belt (not shown), and the basket is connected to the upper part of the shaft 14. 11 is rotated. The basket 11 is provided with innumerable holes, and the melt is separated from the ice by the centrifugal force generated by the rotation of the basket 11, and the melt is discharged from these countless holes toward the inner side surface of the casing 12. The The melt separated by the melt receiver 15 provided in the lower portion of the basket 11 is received, and finally the melt is discharged to the outside from the discharge pipe 13 connected to the melt receiver 15. . The upper part of the casing 12 is covered with a lid 16 to which the heater device 2 is attached. As shown in FIG. 5, the lid 16 can be opened and closed by a hinge or the like. In the present embodiment, ice is supplied by opening the lid 16, but not limited to this, an ice supply pipe (not shown) is separately provided in the casing 1, the lid 16, the duct 21, and the like. Ice may be supplied from there.

  The heater device 2 is a device that supplies hot air for melting the ice stored in the basket 11 of the centrifuge 1. The heater device 2 includes a duct 21, a filter 22 attached to a front end portion of the ventilation inlet of the duct 21, a damper 23 that adjusts the air flow rate, and a heater 24 that heats the taken-in air. Yes. Regarding the arrangement relationship of the filter 22, the damper 23, and the heater 24, the damper 23 is provided on the base end side of the duct 21 with respect to the filter 22, and the heater 24 is attached to the base end side of the duct 21 with respect to the damper 23. However, it is not limited to this relationship. As described above, the air heated by the heater 24 is taken into the centrifuge 1 by the entrainment of the air by the rotation of the basket 11, so that the efficiency is high. By providing the damper 23, the amount of air sucked can be adjusted, so that the melting rate can be controlled. In addition, when the resistance of the filter 22 is strong and air is not taken into the basket 11 even when the air is entrained by the rotation of the basket 11, a separate fan (not shown) is attached to the heater device 2, thereby Air may be supplied.

As described above, how much the melt is separated from the ice during a certain time depends on the centrifugal force generated by the rotation of the basket 11 and the melting speed at which the ice melts. Therefore, the centrifugal force MV ² / r (r) is a function of the circumferential speed V (m / sec) at which the basket 11 rotates (V = rω: r is the radius (m) of the basket 11 and ω is the angular speed (rad / sec)). kg · m / sec ² ) (M is the mass of the mass (kg)), the temperature of the heater that determines the melting rate, and the amount of air sucked can be adjusted to control the separation performance of the melt from ice. it can.

Next, a method of using this batch type melt separation apparatus will be described.
First, ice formed by freezing the target solution is stored in the basket 11 of the centrifuge 1 as shown in FIG. A container 3 for collecting the melt is installed below the outlet 13A of the discharge pipe 13. Then, with the lid 16 closed, the damper 23 is opened to a predetermined amount, and the basket 11 is rotated with the heater 24 set to a desired temperature. After a while, the melt flows down from the outlet 13A and is stored in the container 3 by the centrifugal force generated by the rotation of the basket 11 and the air heated by the heater device 2. When the molten solution becomes full in the container 3, another container 3 may be installed and the molten solution may be collected sequentially. In this way, the melt that transitions from the high concentration stage to the low concentration stage can be recovered in multiple stages. This batch type melt separation apparatus can be suitably used when a small amount of solution is concentrated. In addition, high concentration concentration can be performed by carrying out the process of refreezing the low-concentration late-melt and re-thawing the generated ice.

<Configuration of continuous melt separator>
As shown in FIG. 6, the continuous melting and separating apparatus according to the present invention includes a continuous centrifugal separator 4 that separates a melt from ice, and a heater 5 incorporated in the centrifugal separator 4. .

  In the present embodiment, the centrifugal separator 4 adopts a centrifugal sedimentation type continuous screw decanter type. The centrifuge 4 includes a pipe line 41 that guides the introduced ice to the inside, a bowl 42, and a screw conveyor 43 that scrapes the residual ice separated from the melt and discharges it to the outside. More specifically, a bowl 42 is housed in a casing 44, and a screw conveyor 43 is housed in the bowl 42. In addition, the driving force of the motor 45 is transmitted via the speed reducer 46 so that these rotate. Note that the screw conveyor 43 rotates slightly slower than the rotation of the bowl 42. The formed ice continuously produced by the continuous ice making machine 6 is introduced from the ice inlet 41A, and stays on the surface of the rotating bowl 42 through the ice inlet 41A, through the pipe line 41.

  Here, since the heater 5 for heating the surface of the bowl 42 is incorporated, the ice staying on the surface in the bowl 42 is heated and a part thereof melts to generate a melt. The melt is discharged from a discharge hole 42A formed in the bowl 42, and finally discharged from the melt discharge port 44A. On the other hand, surplus ice remaining due to the generation of the melt is scraped toward the tip of the conical portion of the bowl 42 by the rotation of the blades of the screw conveyor 43, and from the discharge hole 42B formed on the tip side. It is discharged and finally discharged from the residual ice discharge port 44B of the casing 44.

  In this continuous melting and separating apparatus, how much the melt is separated from the ice in a certain time depends on the peripheral speed V (m / sec) of the bowl 42 and the screw conveyor 43 and the melting speed at which the ice melts. is doing. Therefore, by adjusting the respective peripheral speeds V (m / sec) of the bowl 42 and the screw conveyor 43 and the heater temperature that determines the melting speed, it is possible to control the separation performance for separating the melt from the ice.

Next, a method for using this continuous melt separation apparatus will be described.
First, generated ice formed by freezing the target solution by the continuous ice making machine 6 is sequentially put into the ice loading port 41 </ b> A of the centrifuge 4. The charged ice stays on the surface in the bowl 42 that rotates through the pipe 41. The ice staying at the heater 5 set at a predetermined temperature is heated to partially melt to generate a melt, and the melt is discharged from the melt outlet 44A through the discharge hole 42A. The surplus ice remaining due to the generation of the melt is scraped toward the tip of the conical portion of the bowl 42 by the rotation of the screw of the screw conveyor 43, and the residual ice discharge port 44B is discharged via the discharge hole 42B. Discharged from.

  Regarding the recovery of the melt, if the heater temperature and the peripheral speed V (m / sec) of each of the bowl 42 and the screw conveyor 43 are determined in advance so that the melt having a predetermined concentration can be recovered, the melt is continuously collected. A melt having a predetermined concentration can be recovered. For example, when the solution having a predetermined concentration is an initial melt corresponding to, for example, 30% of the produced ice, 30% of the added produced ice is thawed, and the remaining ice of 70% remaining after centrifugation is obtained. If the speed and temperature are adjusted in advance so as to be discharged, a solution having a predetermined concentration can be continuously collected. If the low-concentration late thawing solution is frozen again and the generated ice is thawed again, the concentration can be further increased.

It is explanatory drawing of the outline of a melt-separation experiment method. It is a graph which shows the density | concentration of the melt | dissolution liquid which melt | dissolved the produced | generated ice which frozen the stock solution density | concentration NaCl 3.5% aqueous solution, and collect | recovered multistage. It is a graph which shows each density | concentration of the melt | dissolution liquid which thaw | melted the production | generation ice which frozen stock solution concentration NaCl 3.5%, 10% aqueous solution, and was collect | recovered multistage. It is sectional drawing of a batch type melting separation apparatus. It is explanatory drawing of the state which opened the lid | cover. It is sectional drawing of a continuous-type melt separation apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Centrifugal separator, 2 ... Heater apparatus, 3 ... Container, 4 ... Centrifugal separator, 5 ... Heater, 6 ... Continuous ice making machine, 11 ... Basket, 12 ... Casing, 13 ... Discharge pipeline, 13A ... Outlet, 14 ... Shaft, 15 ... Melt receiver, 16 ... Lid, 21 ... Duct, 22 ... Filter, 23 ... Damper, 24 ... Heater, 41 ... Pipe line, 41A ... Input port, 42 ... Bowl, 42A ... Discharge hole, 42B ... Discharge hole, 43 ... clew conveyor, 44 ... casing, 44A ... melt discharge port, 44B ... residual ice discharge port, 45 ... motor, 46 ... speed reducer, 47 ... main bearing.

Claims (2)

A thawing / separation apparatus for separating a thawing solution from produced ice obtained by freezing a target solution,
The melting and separating apparatus includes a centrifuge having a basket, and a heater device that feeds heated air into the basket.
The heater device includes a duct, a heater that is attached to the duct and heats the taken-in air, and a damper that adjusts the air flow rate.
By controlling at least the peripheral speed at which the basket rotates, the heating amount of the heater and the amount of ventilation by the damper, the amount and concentration of the extracted melt can be adjusted,
A melting separation apparatus characterized by the above. A thawing / separation apparatus for separating a thawing solution from produced ice obtained by freezing a target solution,
The melting and separating apparatus comprises a continuous centrifuge having a bowl and a screw conveyor, and a heater for heating the bowl surface,
At least, the amount and concentration of the melt to be extracted can be adjusted by controlling the peripheral speed at which the bowl rotates and the heating amount of the heater.
A melting separation apparatus characterized by the above.

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