KR101023653B1 - Vaporization crystallizer with movable stirrer and evaporative cristallization method using the same - Google Patents

Abstract

The present invention relates to an evaporation crystallizer, comprising: a reactor containing the solution; A vacuum device for evacuating the inside of the reactor; A stirrer rotatably installed in the reactor to agitate the solution contained in the reactor; A rotating shaft for rotating the stirrer; A driving unit for driving the rotating shaft; And a liquid level controller connected to the rotary shaft, wherein the stirrer is capable of elevating inside the reactor by the liquid level controller, and suppresses unwanted nucleation by controlling the degree of supersaturation using a liftable plate-shaped stirrer. And promote the growth of crystals.

Description

Vaporization crystallizer with movable stirrer and evaporative cristallization method using the same}

The present invention relates to an evaporation crystallizer, and more particularly, to an evaporation crystallizer and a method of evaporation crystallization using the same to suppress unwanted nucleation and promote crystal growth.

As a method of crystallization, the evaporation crystallization method which crystallizes by raising the density | concentration of the substance which crystallizes by evaporating a solvent is known.

In the case of the conventional evaporation crystallizer used in such an evaporation crystallization method, the degree of supersaturation is mainly induced by evaporating the solvent by vacuuming the inside with stirring in a batch reactor.

However, the conventional evaporation crystallizer has a problem that it is difficult to control the degree of supersaturation. That is, to control the degree of supersaturation of the solution using a conventional evaporation crystallizer, it is necessary to change the temperature or the pressure. However, the evaporation crystallization method is mainly used when the material to be separated by crystallization has a small solubility difference due to temperature or the material is decomposed at high temperature. Therefore, it is practically impossible or very difficult to control the supersaturation by changing the temperature. Inefficient In addition, the method of controlling the degree of supersaturation by changing the evaporation rate by adjusting the pressure is not easy to control the degree of supersaturation due to the slow response due to the pressure change.

In addition, the conventional evaporation crystallizer has a problem that the supersaturation generation region and the distribution region of the crystal is inconsistent. That is, in the conventional batch evaporation crystallizer, since the evaporation occurs at the upper surface of the solution, the supersaturation is mainly generated in the upper layer, but the distribution of the crystal is mainly high in the lower layer due to the weight of the crystal. Even if the solution is sufficiently mixed through agitation, the problem of inconsistency between the supersaturation region and the crystal distribution region has its limitations.

Therefore, the first problem to be solved by the present invention is to induce crystals to collect in the upper layer to match the supersaturation region and the densities of the crystals, and to control the supersaturation in the upper layer by using the unsaturated solution in the lower layer to promote crystal growth and nucleus. It is to provide an evaporation crystallizer that can suppress the production.

In addition, a second problem to be solved by the present invention is to provide an evaporation crystallization method for growing a crystal using the evaporation crystallizer described above.

The present invention to achieve the first object,

In an evaporation crystallizer which evaporates a solution to grow crystals,

A reactor containing the solution;

A vacuum device for evacuating the inside of the reactor;

A stirrer rotatably installed in the reactor to agitate the solution contained in the reactor;

A rotating shaft for rotating the stirrer;

A driving unit for driving the rotating shaft; And

And a liquid level controller connected to the rotating shaft.

The stirrer provides an evaporative crystallizer, characterized in that the elevating in the reactor by the liquid level controller.

Here, a liquid level sensor for measuring the liquid level inside the reactor is provided on one side of the reactor, the liquid level controller may control the lifting of the stirrer according to the measured value of the liquid level sensor.

In addition, the stirrer is preferably a plate-shaped stirrer for partitioning the solution inside the reactor up and down.

In addition, the stirrer includes a disk and a stirring projection formed on the upper surface of the disk, the stirrer is preferably stirred the solution of the upper of the solution in the reactor partitioned up and down by the disk.

In addition, the outer diameter of the stirrer is smaller than the inner diameter of the reactor, the flow path of the solution may be formed inside the reactor through a passage between the reactor and the stirrer.

In addition, the disk is composed of a plurality of disk blades arranged in a radial direction along the center of the stirrer, the disk blade is preferably a part that is folded or folded in accordance with the rotation direction of the stirrer.

According to another embodiment of the present invention,

In an evaporation crystallizer which evaporates a solution to grow crystals,

A storage tank for storing the solution;

A first stirrer rotatably installed in the storage tank to stir the solution contained in the storage tank;

A reactor installed in fluid communication with the storage tank through a connection pipe and generating the crystal by evaporating the solution;

A vacuum device for evacuating the inside of the reactor; And

And a second stirrer rotatably installed inside the reactor to stir the solution in the reactor,

The connecting pipe provides an evaporation crystallizer, characterized in that the liquid level control valve for controlling the internal liquid level of the reactor is installed.

Here, one side of the reactor may be provided with a liquid level sensor for measuring the liquid level inside the reactor.

In addition, the liquid level controller for controlling the opening and closing of the liquid level control valve may be further provided according to the measured value of the liquid level sensor.

In addition, the liquid level control valve is preferably a check valve for supplying the solution from the storage tank to the reactor.

The present invention to achieve the second object,

Provided is an evaporation crystallization method in which crystals are grown using the evaporation crystallizer described above.

According to the present invention, it is possible to promote crystal growth and suppress nucleation by matching a supersaturation-producing region with a crystal dense region. In addition, it is possible to easily control the supersaturation of the upper portion by separating the solution in the upper and lower portions through the elevating plate stirrer and using the unsaturated solution located at the bottom. In this process, the swing effect of the stirrer can be induced several times, thereby further improving the distribution and quality of the crystal.

Hereinafter, the present invention will be described in more detail with reference to preferred examples. However, these examples are intended to illustrate the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited thereby.

1 is a schematic diagram of an evaporative crystallizer according to an embodiment of the present invention. The evaporation crystallizer 10 is a reactor (1) containing a solution in which the material to be crystallized dissolved, a vacuum device (7) for evacuating the inside of the reactor, a stirrer rotatably installed inside the reactor to stir the solution contained in the reactor (2), a rotating shaft 3 for rotating the stirrer, a driving unit 4 for driving the rotating shaft, and a liquid level controller 5 connected to the rotating shaft.

The reactor 1 may be manufactured in the form of a double jacket to enable heating or cooling.

The solution (s) to be crystallized is contained in the reactor (1), which is stirred by a stirrer (2) rotatably installed in the reactor (1). In addition, the upper part of the reactor 1 is provided with a vacuum device 7 for evacuating the inside of the reactor. The vacuum apparatus 7 sucks air in the reactor through a vacuum pump (not shown) to accelerate the evaporation crystallization process.

The stirrer 2 is coupled with a rotating shaft 3 for rotating the stirrer, and one end of the rotating shaft 3 is provided with a drive unit 4 (for example, a motor) for driving the rotating shaft.

The rotary shaft 3 may be disposed inside the reactor through the cover c of the reactor 1, which is isolated from the outside for vacuum, and to rotate or lift the stirrer 2 through the rotary shaft 3. do.

The specific configuration of the stirrer 2 is shown in FIG. The stirrer 2 according to the present invention is a plate having a disk, which is composed of a plurality of disk wings 2a arranged in the circumferential direction along the center of the stirrer 2. In addition, a stirring protrusion 2b is formed on the upper surface of the disc blade 2a to stir the upper solution in the solution inside the reactor partitioned up and down by a plate-shaped stirrer. The shape of the stirring protrusion 2b is not particularly limited, and any form can be used as long as the solution can be sufficiently stirred through the rotation of the stirrer.

The disc blade 2a is configured to be foldable so that a part 2a 'can be folded or unfolded according to the rotation direction of the stirrer 2. That is, FIG. 2 (a) is a view showing a stirrer when the disk blade portion 2a 'is folded, and FIG. 2 (b) is a view showing a state in which the disk blade portion 2a' is unfolded. . During the crystallization reaction, a portion (2a ') of the disk blade is fully extended to form a plate shape, through which the solution inside the reactor is partitioned up and down, and the seed is introduced onto the plate-shaped stirrer to form crystals on the stirrer. Therefore, according to the present invention, it is possible to match the supersaturation density area with the crystal production area.

The foldable disc blade (2a) can be folded or unfolded by using the acceleration part 2a ', when the rotation in one direction is folded to form a complete circular plate, when rotating in the other direction the opposite It folds into a pinwheel shape. It rotates the rotating shaft 3 in one direction during the crystallization reaction to expand the disk blades to separate the upper and lower parts, and when the crystallization reaction is finished to extract the crystal through the hole (not shown) in the lower part of the reactor, It can be rotated in the direction to fold the disk blades into a pinwheel shape, causing the crystal to fall down. Such a foldable disc blade may be manufactured to be unfolded or folded only when a certain acceleration or more is applied by using magnetic force or friction force so as not to be unfolded or folded easily.

The disk blades 2a forming the plate-shaped stirrer 2 partition the solution inside the reactor up and down. The upper solution s1 located above the disk wing 2a is evaporated while being stirred by the stirring protrusion 2b formed on the upper surface thereof, so that the supersaturation is further increased to generate and grow crystals, and the lower portion located below the disk wing 2a. The solution s2 remains unsaturated because it is not affected by the stirring action by the stirrer.

On the other hand, the outer diameter of the stirrer 2 is smaller than the inner diameter of the reactor 2. Therefore, a passage is formed between the stirrer and the reactor, and when the stirrer is lowered, the lower solution s2, which is an unsaturated solution, is mixed with the upper solution s1 so that the supersaturation of the upper solution s1 can be easily adjusted. have.

In other words, the upper solution (s1) is crystal growth through evaporation, and in the process of crystal growth, the lower solution (s2), which is an unsaturated solution, again prevents nucleation by controlling the degree of supersaturation in the upper solution (s1). Move to. Control of the degree of super saturation by mixing the lower solution (s2) and the upper solution (s1) can be achieved by lowering the stirrer inside the reactor.

That is, the present invention can easily control the degree of supersaturation by using such a liftable stirrer to prevent undesired nucleation and at the same time promote the growth of crystals.

The lifting and lowering of the stirrer may be made by the liquid level controller 5. The liquid level controller 5 is connected to the rotating shaft and is a means for raising and lowering the stirrer in the height direction of the reactor. An actuator using hydraulic or pneumatic pressure may be preferably used.

In order to more precisely control the lifting of the stirrer, one side of the reactor may be provided with a liquid level sensor 6 for detecting the liquid level inside the reactor. By measuring the liquid level in the reactor through the liquid level sensor 6, and detects the amount of change can be controlled by the liquid level controller 5 to lower the stirrer 2 by a predetermined amount to adjust the supersaturation of the upper solution (s1). In other words, the lifting and lowering of the stirrer 2 can be controlled through the liquid level controller 5 according to the measured value of the liquid level sensor 6.

The liquid level sensor 6 measures the liquid level of the supersaturated solution inside the reactor, and is used as a means for measuring the liquid level in the reactor so that crystals can be grown while preventing nucleation.

The liquid level sensor is a capacitive liquid level sensor that detects the liquid level by measuring the capacitance, a microwave liquid level sensor that measures the liquid level by measuring the time from the measurement surface to be reflected by the microwave, and the pulse of the ultrasonic wave transmitter. Any level can be used as long as it can measure the liquid level inside the reactor without being limited to the kind, such as an ultrasonic liquid level sensor that detects the pulse reflected by the receiver and returned to the surface of the measurement object.

Brief description of the evaporation crystallization method using the evaporation crystallizer 10 according to an embodiment of the present invention.

The solution in which the substance to be crystallized is dissolved is injected into the reactor 1 in which the stirrer 2 is installed, and the inside of the reactor is evacuated while stirring the upper solution s1. A seed is added to the upper solution s1 to crystallize the solution through evaporation. At this time, the disk blade 2a of the stirrer 2 is fully extended, and has comprised the plate shape. Thus, crystals can be grown on a plate-shaped stirrer.

As the evaporation process proceeds, the stirrer 2 is lowered down through the liquid level controller so as to control the supersaturation of the upper solution, which is gradually increased, and the lower solution s2, the unsaturated solution, is the upper solution s1. Mix with As such, when the crystal is grown while maintaining the supersaturation degree of the upper solution at a predetermined level using the elevating stirrer, it is possible to continuously grow the crystal while preventing nucleation. In addition, the swing speed of the stirrer can be precisely controlled by using a liquid level sensor to induce multiple swinging effects, thereby increasing the quality of the crystals by uniformly distributing the crystals.

3 is a schematic diagram of an evaporative crystallizer 10 'according to another embodiment of the present invention.

Hereinafter, a description will be given focusing on differences from the evaporation crystallizer 10 shown in FIG. 1.

In the evaporation crystallizer 10 ′ shown in FIG. 3, the upper and lower solutions partitioned by the plate-shaped stirrer in the evaporation crystallizer shown in FIG. 1 are divided into the reactor 1 and the storage tank 11, respectively. Can be implemented.

That is, the evaporation crystallizer 10 'is a storage tank 11 in which an unsaturated solution is stored, a first stirrer 12 rotatably installed in the storage tank to stir the solution contained in the storage tank, and a storage tank and a connection pipe. A reactor (1) installed in fluid communication via (8) and producing a crystal by evaporating the solution, a vacuum device (7) for evacuating the reactor interior, and a second rotatably installed within the reactor to stir the solution in the reactor It comprises a stirrer (2). In addition, the connection pipe (8) is provided with a liquid level control valve (9) for adjusting the liquid level inside the reactor (1) can be maintained within a certain level of the supersaturation of the solution in the reactor.

The liquid level control valve 9 is preferably a check valve for supplying a solution from the storage tank 11 to the reactor 1. Therefore, backflow from the reactor to the storage tank can be prevented.

The first stirrer 12 and the second stirrer 2 described above are provided to be rotatable by the first rotary shaft 13 and the second rotary shaft 3, respectively.

One side of the reactor 1 is provided with a liquid level sensor 6 can detect the internal liquid level in real time. In addition, the liquid level controller 5 for adjusting the opening and closing of the liquid level control valve and the amount of opening and closing according to the measured value of the liquid level sensor may be further provided. The liquid level controller 5 is a mechanism for operating the opening and closing of the liquid level control valve 9 automatically or manually, and the type thereof is not particularly limited. The level of supersaturation in the reactor 1 can be adjusted by measuring the level of the liquid in the reactor through the liquid level sensor 6 and sensing the amount of change to open the level control valve 9 by a predetermined amount through the level controller 5. Thus, crystal growth inside the reactor can be achieved without nucleation, thereby further increasing the crystal growth efficiency.

The evaporation crystallizer according to another embodiment of the present invention replaces the storage device and the reactor which are separated from each other, and the second stirrer installed inside the reactor may be fixed to the reactor.

An evaporation crystallization method for growing crystals using an evaporation crystallizer according to another embodiment of the present invention is briefly described as follows.

In the storage tank 11 and the reactor 1 in which the first stirrer 12 and the second stirrer 2 are respectively installed, a solution in which the substance to be crystallized is dissolved is injected and the solution is stirred. In addition, the inside of the reactor 1 is evacuated using the vacuum apparatus 7, and seeds are introduced to grow crystals through evaporation crystallization inside the reactor. During the growth of the crystals, the supersaturation of the solution in the reactor is controlled to open the level control valve 9 to prevent nucleation so that the unsaturated solution from the storage tank is fed into the reactor.

As such, crystals may be grown through evaporation inside the reactor, and at the same time, an unsaturated solution may be supplied from the storage tank to maintain a degree of supersaturation in the reactor, thereby suppressing nucleation in the reactor. The degree of supersaturation in the reactor can be more precisely controlled through the liquid level sensor and the liquid level controller.

1 is a schematic diagram of an evaporative crystallizer according to an embodiment of the present invention.

2 is a schematic diagram of a stirrer according to an embodiment of the present invention.

3 is a schematic diagram of an evaporative crystallizer according to another embodiment of the present invention.

Claims (11)

In an evaporation crystallizer which evaporates a solution to grow crystals, A reactor containing the solution; A vacuum device for evacuating the inside of the reactor; A stirrer rotatably installed in the reactor to agitate the solution contained in the reactor; A rotating shaft for rotating the stirrer; A driving unit for driving the rotating shaft; And And a liquid level controller connected to the rotating shaft. The stirrer is an evaporation crystallizer, characterized in that the elevating in the reactor by the liquid level controller. The method of claim 1, A liquid level sensor for measuring the liquid level inside the reactor is provided on one side of the reactor, And the liquid level controller controls the raising and lowering of the stirrer according to the measured value of the liquid level sensor. The method of claim 1, The stirrer is an evaporation crystallizer, characterized in that the plate-shaped stirrer for partitioning the solution inside the reactor up and down. The method of claim 1, The stirrer includes a disk and a stirring protrusion formed on the upper surface of the disk, And said stirrer stirs the solution of the upper part of the solution in said reactor partitioned up and down by said disk. The method of claim 3, The outer diameter of the stirrer is smaller than the inner diameter of the reactor, Evaporation crystallizer, characterized in that the flow path of the solution is formed inside the reactor through the passage between the reactor and the stirrer. The method of claim 4, wherein The disk is composed of a plurality of disk wings arranged radially along the center of the stirrer, The disk blade is evaporation crystallizer, characterized in that a part of the folding or folding according to the rotation direction of the stirrer. In an evaporation crystallizer which evaporates a solution to grow crystals, A storage tank for storing the solution; A first stirrer rotatably installed in the storage tank to stir the solution contained in the storage tank; A reactor installed in fluid communication with the storage tank through a connection pipe and generating the crystal by evaporating the solution; A vacuum device for evacuating the inside of the reactor; And And a second stirrer rotatably installed inside the reactor to stir the solution in the reactor, Evaporation crystallizer, characterized in that the connection pipe is provided with a liquid level control valve for controlling the internal liquid level of the reactor. The method of claim 7, wherein Evaporation crystallizer, characterized in that the one side of the reactor is provided with a liquid level sensor for measuring the liquid level inside the reactor. The method of claim 8, Evaporation crystallizer further comprises a liquid level controller for controlling the opening and closing of the liquid level control valve in accordance with the measured value of the liquid level sensor. The method of claim 7, wherein And the liquid level control valve is a check valve for supplying the solution from the storage tank to the reactor. An evaporation crystallization method in which crystals are grown using an evaporation crystallizer according to claim 1.

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