JP4354582B2 - Crystal purification apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a crystal purification apparatus and method for purifying a crystal by bringing a raw material crystal containing impurities into countercurrent contact with a melt of a purified crystal component.
[0002]
[Prior art]
Conventionally, there are various types of crystal refining apparatuses, but there is an apparatus disclosed in, for example, Japanese Examined Patent Publication No. 47-40621 as an apparatus for purifying crystals using a melt of a crystal component. As shown in FIG. 3 of the accompanying drawings, this known apparatus is provided with a screw conveyor 13 in a charging port 12 as means for supplying raw crystal as a material to be purified containing impurities at the bottom into a purification tower 11. The melting crystal is melted by a heating and melting device 14 provided at the upper part of the tower, and the purified crystal is brought into countercurrent contact with the rising liquid and the crystal rising in the purification tower 11, and the purified crystal is removed from the upper outlet. 15 constitutes an upright purifier. In the refining tower 11, a stirrer 18 having a rotating shaft body 16 and a stirring blade 17 is provided, and this stirrer 18 has a function of lifting the crystal supplied from the charging port 12 while unraveling it.
[0003]
In order to purify a crude crystal containing impurities by using the melt of the target crystal component by the crystal purification apparatus having such a configuration, the raw material crude crystal is supplied into the tower through the charging port 12 of the purification tower 11, It is lifted toward the top of the tower by a stirrer 18 provided in At that time, the stirrer 18 unraveles the crystals and prevents the crystals from adhering to the stirring blades 17 while transporting up the purification tower 11 while preventing the crystals from rising as a lump or adhering to the stirring blades 17. Thus, the crystals that have reached the top of the tower are melted in a necessary amount to become a refluxing melt, descended in the purification tower 11 by gravity, and the crystals that have reached the top of the tower while being washed with this melting liquid are collected with the desired purity. It is taken out from the outlet 15. The impurities contained in the raw material crystals descend in the purification tower 11 and are separated by the filtering device 19 and removed from the outlet 20.
[0004]
[Problems to be solved by the invention]
However, in this refining apparatus, since the heating and melting apparatus 14 is installed in the upper part of the tower, the heating and melting apparatus 14 receives a pressure stronger than the rising crystal, and further, the load on the stirrer 18 is caused by the reaction force of the pressure. As a result, the heating and melting apparatus and the stirrer may be damaged.
[0005]
In the meantime, in order to prevent such a problem in operation, it is necessary to reduce the processing amount of crystals, resulting in a decrease in production capacity. In addition, if the heating and melting apparatus is reduced in order to reduce the pressure, the heat transfer area is reduced, so if the same amount of supplied heat is secured with the heating and melting apparatus, the temperature of the melt rises. This causes the problem that the melt is altered.
[0006]
Furthermore, in this type of apparatus, the amount of rising of the crystal may fluctuate, but it is difficult to cope with this. That is, in the apparatus of FIG. 3, since the control of the apparatus adjusts the temperature and the amount of the melt by adjusting the temperature of the heating and melting apparatus, the adjustment of the temperature and the amount of the melt is indirectly performed. Made. Therefore, this control is extremely difficult to be performed under appropriate conditions, and the operating conditions fluctuate. The heat transfer coefficient is also affected, and as a result, the amount of heat given by the heating and melting apparatus also fluctuates and becomes unstable. As a result, the crystal was altered by heat and the purification ability was lowered.
[0007]
In view of such circumstances, an object of the present invention is to provide a crystal purification apparatus and method that can directly control conditions such as the temperature and amount of a melt to stably purify a high-quality product with high performance.
[0008]
[Means for Solving the Problems]
The crystal refining apparatus according to the present invention has a raw material crystal charging port at the lower part of a cylindrical refining tower extending in the vertical direction, and an outlet for taking out the purified crystal as a product at the upper part. In this purification tower, a stirrer for stirring the raw material crystal is arranged, and the raw material crystal is purified by countercurrent contact between the falling melt of the purified crystal component and the rising raw material crystal in the purification tower. Is done.
[0009]
In such a crystal purification apparatus, the present invention is characterized in that a melt supply means for supplying a melt of the purified crystal component from the outside into the purification tower is provided in the upper part of the purification tower.
[0010]
In such an apparatus of the present invention, the melt of the purified crystal component is supplied from the outside to the purifier tower at the upper part of the purifier tower, and the ascending raw material crystal is the descended melt of the purified crystal component in the purifier tower. And purified in countercurrent contact.
[0011]
In the present invention, it is preferable that the stirring device can be pushed upward together with the stirring of the raw crystal. In that case, the stirring device may have a stirring blade attached to a rotating shaft that extends in the longitudinal direction. The stirring device may have a plurality of rotating shaft bodies, and a rotating blade may be attached to each rotating shaft body. At this time, at least one of the plurality of rotating shaft bodies can be rotated in the opposite direction to the other rotating shaft bodies. If the rotating blades attached to the plurality of rotating shaft bodies are partially overlapped with each other when viewed from the axial direction of the rotating shaft body, the stirring effect is improved.
[0012]
Furthermore, in the present invention, it is desirable that a supply device that can push the raw material crystal into the purification tower is connected to the charging port, whereby the supply ability of the raw material crystal can be improved. The purification tower is preferably provided with a filtration device at the bottom and an impurity discharge port below it.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2 of the accompanying drawings.
[0014]
In the figure, the purification tower 1 has a vertical cylindrical shape, and a stirrer 2 is disposed therein. In this embodiment, the stirring device 2 has two rotating shaft bodies 2A extending vertically, and a plurality of stirring blades 2B are attached to each rotating shaft body 2A. The two rotating shaft bodies 2A may rotate in the same direction or in opposite directions. In any case, it is preferable that the stirring blade 2B has an inclination angle with respect to a horizontal plane that forms an upward flow when the rotary shaft 2A rotates. The stirring blades 2B attached to the two rotary shaft bodies 2A are, as seen in FIG. 2 as a preferred embodiment in this embodiment, so that the rotation surfaces of both stirring blades 2B partially overlap when viewed from above. It has become. The stirring ability is improved in this overlapping region. The inner wall surface of the purification tower 1 preferably has a shape close to the circle of the rotating surface.
[0015]
A charging port 3 is provided in the lower part of the purification tower 1, from which raw material crystals are supplied. Although not shown, the charging port 3 is preferably provided with a supply device such as a screw conveyor so that the raw material crystals can be pushed into the purification tower 1.
[0016]
In the upper part of the purification tower 1, there are provided an outlet 4 for taking out the purified crystal as a product, and a melt supply means 5 for supplying a melt of the purified crystal component from the outside into the purification tower. ing. In the present embodiment, the melt supply means 5 is in the form of a supply pipe so that a predetermined amount of a melt whose temperature and the like are accurately known in advance is supplied.
[0017]
Further, a filtration device 6 is disposed in the lower part of the purification tower 1, and an impurity discharge port 7 is provided at the bottom.
[0018]
In the apparatus of this embodiment, the raw raw crystal or slurry crystal mixture is fed into the purification tower 1 from the charging port 3. The raw material crystals fed in this way are carried to the upper part of the tower while being stirred by the stirrer 2. In the upper part of the tower, the melt of the crystal component is supplied from the outside of the tower from the melt supply means 5. This melt is accurately grasped in terms of temperature and the like, and is supplied in an amount optimal for operation management of the apparatus. A part of the molten liquid descends in the tower and comes into countercurrent contact with the rising raw material crystals. As a result, the rising crystal is washed and purified by exhaling impurities inside the crystal to the outside by the sweating action caused by the temperature rise. When the raw material crystal reaches the top of the tower in this way, the raw material crystal is refined into a high-purity substance, and a part thereof is taken out from the outlet 4 as a product.
[0019]
The low-melting point impurities contained in the raw material crystals descend in the tower, are separated from the crystals by the filtration device 6, and are discharged from the impurity discharge port 7.
[0020]
The present invention is not limited to the specific examples shown in the above embodiments. The melt supply means may not be a supply pipe as shown in the figure, but may be a perforated plate that uniformly drops the melt little by little. Further, the purification tower does not necessarily have to be a cylindrical shape, and can have an arbitrary cross-sectional shape, or may be slightly inclined even if it does not stand upright.
<Example>
In a refining unit with a refining tower with a cross-sectional shape as shown in Fig. 2 in which two cylinders with an inner diameter of 508 mm and a height of about 2600 mm are stacked, a slurry of paradichlorobenzene 92.3%, orthodichlorobenzene 6.6%, and metadichlorobenzene 1.1% The mixture in the state was charged at 1514 kg / Hr, and excluding the molten solution, paradichlorobenzene having a net of 1260 kg / Hr and a purity of 99.99% or more could be obtained. In the refining apparatus disclosed in Japanese Patent Publication No. 47-40621 having the same size as this apparatus, the limit was 800 kg / Hr.
[0021]
【The invention's effect】
As described above, in the present invention, since the heating and melting apparatus is not provided at the upper part of the purification tower unlike the conventional apparatus, the melting apparatus receives pressure from the rising crystal and the stirrer receives the reaction force. The possibility of damaging each was eliminated.
[0022]
Furthermore, since a desired appropriate amount of melt from which the conditions such as temperature are accurately grasped is supplied from the outside, condition control can be performed accurately. As a result, it is possible to stably obtain a high-quality product that is not deteriorated by heat with high refining ability.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an apparatus according to an embodiment of the present invention.
2 is a cross-sectional view of the apparatus shown in FIG. 1 taken along the line II-II.
FIG. 3 is a longitudinal sectional view of a conventional device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Purification tower 2 Stirring apparatus 2A Rotating shaft 2B Stirring blade 3 Charge port 4 Outlet 5 Melt supply means 6 Filtration apparatus 7 Impurity discharge port

Claims (9)

A raw material crystal charging port is provided at the bottom of a cylindrical refining tower extending in the vertical direction, and an outlet for taking out the purified crystal as a product is provided at the top, respectively. In a crystal refining device that is disposed inside and purifies the raw crystal by countercurrent contact between the descending melt of the purified crystal component and the ascending raw material crystal in the purification tower, the melt of the purified crystal component is externally introduced into the purification tower. A crystal refining apparatus, characterized in that a melt supplying means for supplying to the top of the refining tower is provided. The crystal purifier according to claim 1, wherein the stirring device can push up the raw material crystal together with stirring. The crystal refining device according to claim 1 or 2, wherein the stirring device has a stirring blade attached to a rotating shaft body extending in the longitudinal direction. 4. The crystal refining device according to claim 3, wherein the stirring device has a plurality of rotating shaft bodies, and a rotating blade is attached to each rotating shaft body. The crystal refining device according to claim 4, wherein at least one of the plurality of rotating shaft bodies rotates in a direction opposite to that of the other rotating shaft bodies. The crystal refining device according to claim 4 or 5, wherein the rotating blades attached to the plurality of rotating shaft bodies partially overlap each other when viewed from the axial direction of the rotating shaft body. . The crystal purifier according to claim 1, wherein a supply device capable of pushing the raw crystal into the purification tower is connected to the charging port. 2. The crystal purification apparatus according to claim 1, wherein the purification tower is provided with a filtration device at the bottom and an impurity discharge port below the filtration device. A raw material crystal charging port is provided at the bottom of a cylindrical refining tower extending in the vertical direction, and an outlet for taking out the purified crystal as a product is provided at the top, respectively. In the crystal purification method in which the purified crystal component is purified by bringing the purified crystal component descending melt and the ascending raw material crystal into countercurrent contact in the purification tower to purify the raw material crystal, A crystal refining method, characterized in that the lower part is supplied into the refining tower at the top.

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