JPH08119628A - Production of flake salt and device therefor - Google Patents

Abstract

PURPOSE: To produce a flake salt with the quality stabilized more efficiently than the conventional process by using this simple device. CONSTITUTION: A partition plate 3 is provided in the vaporization vessel 1 heat-insulated by an insulating material 2 to separate the vessel into a boiling part 4 and a crystallization part 5. A heating steam jacket 6 is furnished on the periphery of the boiling part 4 to heat the brine. The boiled brine is allowed to overflow the upper part of the plate 3 and introduced into the crystallization part 5, the brine flows simultaneously into the boiling part 4 from the lower part of the plate 3, and the brine is convected. The surface of the crystallization part 5 is not rippled by the boiling, and hence the flake salt having a uniform diameter is formed. Since the brine heated to the b.p. is introduced into the crystallization part 5, the brine is efficiently vaporized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing flake salt, which is used for producing dairy products, fish paste products and the like and is also used as an edible salt.

[0002]

2. Description of the Related Art Flake salts consist of square-shaped pyramid-free tremies, tremie binding products, tremie fragments, etc. (hereinafter referred to as flake salts), which are produced by surface-evaporating a saline solution. The flake salt is characterized by being bulkier than the cubic salt, having good crystallinity and adhesivity with other substances, and having a very high dissolution rate, because of its thin crystal.
Therefore, it is mainly used in the food field such as dairy products and fish paste products.

The flake salt precipitates when the salt solution is heated in a container open to the atmosphere and surface-evaporated. The salt solution can be heated by heating the side or bottom of a container filled with salt solution that is open to the atmosphere, by heating both the side and bottom, or by the inside, and by heating the salt solution outside the container to the atmosphere. There are methods such as returning to an open container.

[0004] In the conventional method of heating the side surface or the bottom, both the side surface and the bottom, or the inside by using a container whose salt solution is opened to the atmosphere to evaporate the surface and deposit the flake salt on the surface of the liquid, the heating part is used. Since the crystallization part coexists, when the salt solution is boiled, cubic salt is precipitated by boiling in the liquid to form a mixture of flake salt and cubic salt. In addition, the liquid surface is disturbed by boiling, and the precipitation of flake salts due to surface evaporation is not stable. For this reason, it is necessary to heat the salt solution while controlling it to a temperature below the liquid temperature at which boiling does not occur in the liquid, but if the liquid temperature is too low, the amount of water evaporated will decrease and the growth rate of crystals will slow down, resulting in poor production efficiency. Deteriorate. Therefore, the liquid temperature is 90 ℃ ~
It is common to evaporate water while controlling the temperature to about 95 ° C. The boiling point of the saturated saline solution is 108.8 ° C. under atmospheric pressure according to “Seawater Utilization Handbook” edited by the Japan Society of Seawater, page 141. Therefore, in this method, the boiling point of the saline solution is 10 ° C. or more lower than the boiling point. Therefore, the amount of water vaporized per unit time and unit area is low and the productivity is poor.

As another method, there is a method in which the flakes are heated by heating them outside the container and discharging them into a container opened to the atmosphere, and flake salts are precipitated by the surface evaporation due to the latent heat of the liquid and the solubility difference due to the temperature drop of the liquid. The salt solution discharged into the container opened to the atmosphere is crystallized and then returned to the heat exchange step to be heated and discharged into the container opened to the atmosphere and circulated. In this method, since the heated saline solution is discharged into a container opened to the atmosphere, the water content evaporates at a temperature lower than the boiling point and while the temperature drops due to heat dissipation, resulting in poor productivity per unit area and unit time. . Furthermore, since the saline solution is forcibly circulated, auxiliary equipment such as a pump is indispensable.

[0006]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a method and an apparatus for producing flake salt efficiently, which is an apparatus having a simple structure, instead of the conventional method.

[0007]

The structure of the present invention for solving the above-mentioned problems is a method for producing flake salt as set forth in the appended claims, and an apparatus therefor. To summarize this, the inside of the evaporation container is divided into a boiling part and a crystallization part by a partition plate, the boiling part is heated to boil the saline solution, and an upward flow is caused in the boiling part. It is a method of causing convection so that the saline solution flows into the boiling portion from the lower part of the partition plate at the same time as overflowing to the crystallization portion. As a device therefor, an evaporation container for evaporating saline solution,
There is a partition plate inside it, having a heating device for heating the boiling part, there is a flow path for the boiling salt solution to overflow into the crystallization part in the upper part of the partition plate, and in the lower part of the partition plate. There is a flow path for the saline solution to flow from the crystallization part to the boiling part.

In the present invention, when the boiling part and the crystallization part are divided in the same container and the boiling part is heated to bring it to boiling, the boiling part reaches the boiling point and the crystallization part is as much as possible. Moisture can be evaporated at a temperature close to the boiling point, and water can be evaporated at a temperature higher by 10 ° C. or more as compared with the conventional method. The boiling portion is in a mixed state of bubbles and liquid due to the boiling state, so that the specific gravity becomes relatively light and becomes higher than the liquid surface of the crystallization portion. By setting the width of the boiling portion to 20 cm or less, preferably 10 cm or less, and the crystallization portion having a width equal to or more than this, preferably 10 times or more, the liquid level difference between the crystallization portion and the boiling portion is in the heating state. It usually changes from 0.5 cm to 1
It will be about 0 cm. Further, by adjusting the width of the crystallization portion, it is possible to adjust the quality of the flake salt, particularly the particle size, by adjusting the growth of crystals of the flake salt to be produced. Further, the evaporation container of the device of the present invention may be open to the atmosphere or may be sealed. The evaporation may be performed under atmospheric pressure, reduced pressure, or increased pressure under the condition that surface evaporation occurs in the crystallization part while the boiling part is in a boiling state. An example of the device of the present invention will be specifically described with reference to the drawings. A partition plate 3 is provided inside the evaporation container 1 that is kept warm by a heat insulating material 2, and the inside of the evaporation container 1 has a boiling part 4 and a crystallization part. Divide into 5 and. Boiling part 4
A heating device 6, for example, a steam jacket is provided on the outer periphery of
Bring the saline solution to a boil. Partition plate 3 for boiling saline
Overflows from above and flows into the crystallization part 5. At the same time, the saline solution flows into the boiling portion from the lower part of the partition plate 3, and the convection of the saline solution occurs. The surface of the crystallization part 5 is kept calm without being affected by ripples due to boiling, and water is evaporated from this to form flake salt. The grown flake salt settles from the surface,
At this time, since the mesh plate 7 is at the lower end of the partition plate 3, it is separated from the saline solution flowing into the boiling portion from the lower end of the partition plate, and the container 1
Collect at the bottom of the. When taking out, open the valve and take out from the outlet 9. An amount of saline solution equivalent to the saline solution reduced by evaporation of water and removal of crystals is replenished from the can water tank.

The upper part of the partition plate 3 of the boiling part 4 and the crystallization part 5 is
The shape may be linear or notched as long as the boiling saline solution is rectified, but the linear shape is preferable from the viewpoint of salt adhesion and the like. For heating the boiling portion, it is necessary to adjust the supply amount, temperature, etc. of the heating medium so that the boiling salt solution overflows from the boiling portion having a high liquid level to the upper portion of the partition plate and the boiling salt solution flows into the crystallization portion. The overflow rate of the boiling salt solution is related to the growth rate of the flake salt in the crystallization part, and in the case of excess, the flake salt production efficiency is improved, but the flake salt becomes smaller, and conversely, in the case of being too small, the flake salt becomes The salt becomes large, but the production efficiency becomes poor. That is, heating of the boiling portion has an important effect on the crystalline state of the flake salt. It is preferable that the lower portion of the partition plate 3 has substantially the same depth as the heating device 6 that heats the boiling portion. Further, in the gap between the crystallization part and the lower part of the partition plate 3, a wire mesh or the like is inserted so that the crystallized flake salt does not mix into the boiling part from the crystallization part, and only the salt solution is kept between the boiling part and the crystallization part. It is preferable to be able to circulate between them.

The salt solution flows from the boiling part to the crystallization part in a mixed phase of bubbles and liquid to generate an ascending flow, and the boiling salt solution overflows from the partition plate and crystallizes by the amount overflowed from the boiling part. A natural circulation system is formed in which the saline solution flows from the boiling part to the boiling part. The lower part of the crystallization portion is preferably provided with a gradient so that the precipitated flake salt can be collected so that the flake salt can be extracted together with the salt solution.

The salt solution is replenished in an amount equal to the amount reduced by evaporation of water. The replenishment is preferably carried out continuously with the saline solution without changing the height of the liquid surface. This is because when the liquid level changes, the overflow rate of the boiling salt solution from the boiling portion to the crystallization portion changes, and the flake salt precipitation state changes. As the salt solution, any of ordinary salt dissolved, sun salt dissolved, brine obtained by concentrating seawater, and salt and sun salt dissolved therein can be used.

[0012]

[Function] By dividing the boiling part and the crystallization part in the same container and heating the boiling part to boil, the boiled saline solution is supplied to the crystallization part at a temperature as close to the boiling point as possible. It becomes flake salt while diffusing on the surface. Since the boiling portion is in a boiling state, the bubbles and the liquid are in a mixed state, and the specific gravity becomes relatively low and the specific gravity becomes higher than the liquid surface of the crystallization portion. In the boiling part, a mixed phase of bubbles and liquid is generated to generate an upward flow, and the boiled saline solution flows upward and overflows the partition plate from the boiling part to the crystallization part. The overflow rate of the boiling salt solution can be adjusted by the supply amount of the heat medium, the temperature, the width of the boiling portion, and the like. The crystallization part is separated from the boiling part and is stable with little disturbance of the liquid surface, so that the flake salt is less likely to settle during growth,
Most of them grow up to the point where buoyancy and self-weight compete with each other, so that the quality of the generated flake salt such as particle size becomes uniform.

[0013]

The present invention will be specifically described with reference to the following examples.

Example 1 A bottom and a side surface of a rectangular tank having a length of 2 m, a width of 1 m and a depth of 0.6 m are kept warm, and a side of the length of 2 m is jacketed and heated with steam. The boiling part was partitioned by a partition plate with a width of 5 cm from the vertical side surface. As the partition plate, a stainless plate having a height of 50 cm from the bottom and a thickness of 2 mm was used, and a punching metal of 1 mm was stretched to a position 10 cm from the lower end of the partition plate. A saturated saline solution is put into this tank and heated.
The salt solution in the boiling part is boiled and overflowed to the crystallization part. The temperature of the crystallization part is around 105 ° C. The liquid level difference between the boiling part and the crystallization part is about 5 cm. Saturation of the performance value under this condition and the uniformity coefficient of the particle size of the produced flake salt in the conventional flat kettle, which is a conventional kettle with 2m in length, 1m in width, 1m in width and 0.4m in depth, keeping the side walls warm. Comparison was made between the performance values when salt water was added and the flake salt was precipitated by heating from the side and bottom and the particle size uniformity coefficient of the generated flake salt.
Shown in the table. Comparing the amount of evaporation of water and the amount of precipitation per unit time and unit area, the present invention shows that compared with the conventional method,
About twice as efficient. Further, the uniformity coefficient of the particle diameter of the flake salt of the present invention is about 40% smaller than that of the conventional method, and the variation of the particle diameter of the flake salt is small and uniform.

Here, the particle size uniformity coefficient is a coefficient representing the variation in particle size, and the 60% by weight passing particle size obtained from a distribution curve showing the relationship between the cumulative weight percentage through sieving and the particle size is 10% by weight. % The value obtained by dividing by the passing particle size. The closer the ratio is to 1, the more uniform the particle size.

[0016]

[Table 1]

[0017]

As described above, according to the present invention, the boiling part and the crystallization part are divided in the same container, the boiling part is heated and boiled, and the partition plate partitioning the boiling part and the crystallization part is boiled. By overflowing the salt solution, the flake salt can be stably deposited and grown at the crystallized portion where the liquid surface is stable. This is because the quality is more stable than the conventional method, the temperature of the boiling part is raised to the boiling point, and the crystallization part can be heated to a temperature as close to the boiling point as possible to evaporate the water content. It is possible to provide a method for producing a flake salt, which is extremely efficient as compared with the method described above, and in which the saline solution naturally circulates between the boiling section and the crystallization section without the need for auxiliary equipment such as a pump. it can.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining an example of an apparatus of the present invention.

[Explanation of symbols]

 1 Evaporation Container 2 Heat Insulation Material 3 Partition Plate 4 Boiling Part 5 Crystallization Part 6 Heating Device 7 Mesh Plate 8 Can Water Tank 9 Outlet

Claims (2)

[Claims] 1. A method for producing a flake salt by surface-evaporating a salt solution, comprising: (1) dividing an inside of an evaporation container into a boiling part and a crystallization part by a partition plate; and (2) mainly heating the boiling part. The salt solution is boiled to generate an ascending flow in the boiling part, and (3) the saline solution overflows from the upper part of the partition plate to the crystallization part, and the saline solution flows into the boiling part from the gap of the lower part of the partition plate. A method for producing a flake salt, which comprises natural circulation. 2. An evaporation container for crystallizing salt by surface-evaporating a salt solution, and a partition plate for dividing the salt solution into a boiling portion and a crystallization portion, and heating the boiling portion. And a flow path is formed in the upper part of the partition plate for the saline solution in the boiling part to overflow to the crystallization part, and in the lower part of the partition plate the saline solution from the crystallization part to the boiling part. An apparatus for producing flake salt, characterized in that a flow path for the inflow of is formed.