JPH10263306A - Crystallizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obviate the fixation of crystals to cooling surfaces and to improve the discharge operability of the crystals and to prevent the degradation in filterability by changing refrigerant inflow conditions to a cooling medium having variability and coolability to allow the cooling medium to continuously or intermittently repeat contraction and expansion, thereby imparting a flow property to a crystal slurry without using a stirrer. SOLUTION: A discharge pump P2 is held stopped and the refrigerant is introduced from an introducing pump P1 to expand a cooling pipe 3a. The introducing pump P1 is then stopped and a refrigerant discharge pipe P2 is activated to shrink bellows 3a. The bellows 3a is expanded and shrunk by such process and eventually vertical motion is induced in the bellows 3a. The amplitude, intervals, time, number of times, etc., thereof are freely selectable by the ways of introducing and discharging the refrigerant. The cooling surfaces are deformed in such a manner, by which the fluidization is imparted to the soln. to be crystallized and the cooling thereof is accelerated without having the stirrer to induce crystal destruction. In addition, the slurry is forcibly discharged outside the system for the structure of the device and, therefore, there is no fixation of the crystals to the cooling surfaces, the discharge operability of the crystals is improved and the degradation in the filterability is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystallization apparatus that does not use a stirrer, and more particularly, to a crystallization apparatus having a variable and movable cooling body having a refrigerant introduced therein.

[0002]

2. Description of the Related Art Crystallization is an operation for depositing crystals from a liquid phase or a gaseous phase, and the precipitation of crystals occurs in a supersaturated state. The supersaturated state is caused by cooling (heating when the saturated concentration is reduced by raising the temperature), evaporation, reaction, pressurization, and the like. In the present invention, the supersaturated state is a case where the liquid phase is crystallized by cooling.

[0003] There are various cases of crystallization depending on the solution state of the target substance and the demand for the obtained crystal.
It is important to select a crystallization apparatus and method depending on the target.

For example, many conventional crystallization apparatuses have a cooling jacket and a stirrer, and maintain a crystal suspension state by stirring. On the other hand, there is a problem that crystal breakage occurs due to stirring. In some cases, the filterability is reduced.

[0005] Therefore, in the case of a material having poor filterability, for example, a certain kind of organic compound (for example, a coupler for a photosensitive material), the crystallization must be performed in a stationary state due to the above-mentioned problems. . Further, when cooling is performed by a jacket or the like, the crystals precipitated on the cooling surface are solidified like a block, making it difficult to discharge from the crystallizer, and using a stirrer to discharge the blocked crystals from the crystallizer. When the block is crushed, there is a problem that some crystals are crushed at that time, and the filterability is deteriorated.

[0006] Therefore, the cooling temperature cannot be reduced so much, and the cooling efficiency (transmission) by the above-mentioned block is affected, thereby increasing the cooling time.

[0007] To solve such a problem, there is a method of directly contacting a refrigerant without using a fixed heat transfer surface. However, in such a case, a device for recompressing and using a refrigerant such as propane, butane, or methane is required, which is costly, and has a problem that scale is easily generated on the nozzle surface. As such an example, see, for example,
No. 27802 describes a direct contact crystallization apparatus that uses a draft tube in combination with a gas or liquid injection nozzle to cool and agitate the crystal slurry. And circulate through the draft tube.

In such a case, since there is no fixed heat transfer surface,
As the refrigerant, nitrogen, helium, and other vaporized liquids are used, and the above-mentioned problems of cost, scale, and the like still remain. In addition, the vaporized liquid causes a violent fluid state due to rapid volume expansion when vaporized, and there is a risk that crystal breakage due to particle collision may occur particularly in a soft organic compound crystal. Further, the supersaturation of the part of the solution in contact with the vaporized liquid at a very low temperature rapidly increases, and very fine natural nuclei are generated, which may deteriorate the filterability.

Further, a crystallizer for suspending a pipe through which a refrigerant is passed in a crystallization tank to form a cooling surface and reciprocatingly rotating the pipe is disclosed in Japanese Patent Publication No. 56-3766.
In this case, there is a possibility of crystal breakage due to collision of the crystal with the cooled tube.

[0010]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a crystal slurry having fluidity without using a stirrer and having no crystals fixed to a cooling surface. Another object of the present invention is to provide a crystallization apparatus which is excellent in the operability of discharging the crystals and can prevent deterioration of the filterability of the obtained crystals.

[0011]

The above object of the present invention is achieved by the following means.

A crystallization apparatus for performing crystallization by cooling, characterized in that the crystallization apparatus has a cooling body in which a refrigerant is introduced, and the cooling body (therefore, its cooling surface) is variable and movable. Crystallizer.

[0013] The crystallization according to the above item, wherein the cooling body is deformed by changing an inflow condition (for example, a flow rate, a flow velocity, an inflow time, an inflow interval, etc.) of an introducing means for introducing a refrigerant into the cooling body. apparatus.

The crystallization apparatus according to the above or the above item, wherein the cooling body into which the refrigerant is introduced repeatedly expands and contracts continuously or intermittently.

Hereinafter, the present invention will be described specifically.

In the present invention, the solution to be crystallized may be a solution in which solids are completely dissolved, or a solution containing several tens of percent of crystals.

The crystallization method of the present invention is applied to crystallization when it is not preferable to use a stirrer. In the present invention, in the crystallization tank, a cooling body through which a refrigerant is provided is installed, and the cooling body itself, that is, a cooling surface has variability and mobility, for example, intermittent expansion and contraction and expansion can be repeated. This is a great feature, whereby the fixation of crystals on the cooling surface can be effectively suppressed.

The material of the cooling body forming the cooling surface is a material having variability and mobility, which does not adversely affect the solution to be crystallized and has durability against the solvent of the solution. If it is not limited. As such a material, for example,
Rubber-based materials (such as fluorine rubber and chloroprene rubber), Teflon, polyethylene, polyvinyl chloride, and other synthetic resins can be used, but a flexible rubber-based material is suitable.

The shape of the cooling body is appropriately selected depending on the cooling area required by the solution to be crystallized to be applied or the desired vibration. For example, the cooling body has a U shape, a spiral shape, a bellows shape, a jacket shape, or the like. Shape.

As described above, the crystallization apparatus of the present invention is applied to a crystallization solution that is preferably left standing without using a stirrer. Organic compounds, for example, couplers for photosensitive materials and the like can be mentioned.

Hereinafter, the crystallization apparatus of the present invention will be specifically described with reference to the drawings.

FIG. 1 is an explanatory perspective view showing one example of the crystallization apparatus of the present invention. In FIG. 1, reference numeral 1 denotes a crystallization tank, and a crystallization tank 1 has an introduction pipe 2 for a solution to be crystallized and a refrigerant introduction pipe 4.
And a refrigerant discharge pipe 5, and a crystallization liquid discharge pipe 6 is provided at the bottom of the tank.
And a bellows-shaped cooling pipe 3a inside the crystallization tank 1.
have. A plurality of cooling pipes can be provided.

The cooling pipe 3a relatively controls the amount and speed of introduction of the refrigerant by the introduction pump P1 attached to the refrigerant introduction pipe 4, and the amount and rate of refrigerant ejection by the discharge pump P2 attached to the refrigerant discharge pipe 5. Thereby, the cooling pipe can be deformed or vibrated.

For example, with the discharge pump P2 stopped,
The cooling pipe 3 is introduced by introducing a refrigerant from the introduction pump P1.
The bellows contracts by expanding a, then stopping the introduction pump P1, and activating the refrigerant discharge pipe P2. This process causes the bellows to expand and contract, resulting in the bellows moving up and down.

The amplitude, interval, time, number of times, etc.
It can be freely selected according to the way of discharging.

FIG. 2 shows a case in which a jacket type cooling surface 3b is provided, and the jacket can be expanded and contracted by the same process as described above.

Deformation of the cooling surface by the process as shown in FIGS. 1 and 2 gives flow to the solution to be crystallized to promote cooling, and also prevents the crystal from sticking to the cooling surface. You can do it.

FIG. 3 shows an application of the present invention. The belt conveyor type crystallization apparatus 12 includes a cooling jacket 13 and an upper and lower belt 14 in contact with the jacket. The solution sent from the solution tank 11 to the crystallizer 12 is cooled and crystallized while moving in the gap between the upper and lower belts 14 and discharged. Since the present device has cooling surfaces above and below and can reduce the distance between the solution and the cooling surface, the solution can be cooled in a short time. In addition, since there is no stirrer that causes crystal destruction, a crystal slurry having good filterability is obtained, and the slurry is forcibly discharged out of the system due to the structure of the apparatus, so that the slurry is easily taken out. In the case of a crystal having strong adhesion, a crystal scraping plate 15 can be provided at the slurry outlet. In addition, the solution tank 1
1 can provide a cooling jacket, lower the temperature of the solution to be crystallized, and perform the initial stage of crystallization.

[0029]

EXAMPLE In the example, a plurality of Teflon bellows cooling tubes 31, 32, 33, 34, 35 were used. FIG. 4A is a sectional view, and the bellows cooling tube is appropriately arranged in a crystallization tank. Reference numeral 2 denotes an inlet pipe for the crystallization liquid, and reference numeral 6 denotes an outlet pipe for the crystallized liquid. Bellows cooling pipe is refrigerant introduction pump P
1. It is connected in parallel with the refrigerant discharge pump P2.

FIG. 4B shows a bellows cooling pipe,
D is the minimum diameter of the pipe, and OD is the maximum diameter. L is the length of the bellows cooling pipe.

800 g of a coupler for a color light-sensitive material was dissolved in 4000 ml of methanol at 60 ° C. and sent to a crystallization tank.

The crystallization tank had a capacity of 5000 ml, in which five bellows cooling tubes shown in FIG. 4A were arranged.
The cooling tube has ID = 16 mm, OD = 25 mm, wall thickness = 1
mm, L = 75 (when contracted) to 140 mm (when expanded).

As described above, first, P2 was stopped, and when cooling water at 8 ° C. was introduced at 50 ml / min for about 8 minutes by P1, the bellows cooling pipe was lowered to a position 50 mm from the bottom of the tank. Next, the pump P1 was stopped, and the refrigerant was discharged from the pump P2 at about 50 ml / min. Thereby, the bellows cooling pipe shrunk to a height of 200 mm from the bottom of the tank.

When this operation was repeated for 10 hours, a crystal slurry having fluidity and good filterability was obtained. The yield was 90%.

On the other hand, the coupler solution was
Using a 1-liter jacketed crystallization tank, crystallization was carried out using the same refrigerant at 8 ° C., and the crystallization was carried out by standing. After 24 hours, the yield was 73%, and it took about 2 days to obtain a yield of 90%. Cost me. Further, after crystallization, a very hard cake having a thickness of about 2 cm was formed on the cooling surface, and it was difficult to discharge the crystal slurry.

[0036]

Industrial Applicability According to the present invention, it is possible to obtain a crystal slurry having fluidity of a crystal slurry without using a stirrer, free of crystal sticking to a cooling surface, and excellent in operability of discharging the crystal. A crystallizer capable of preventing deterioration of the properties can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory perspective view showing one example of a crystallization apparatus (bellows type) of the present invention.

FIG. 2 is an explanatory sectional view showing one example of a crystallization apparatus (jacket type) of the present invention.

FIG. 3 is an explanatory sectional view showing one example of a belt conveyor type crystallization apparatus of the present invention.

FIG. 4 is a crystallization apparatus used in Examples.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crystallization tank 2 Solution introduction pipe to crystallize 3a Bellows type cooling pipe 3b Jacket type cooling pipe 31-35 Bellows type cooling pipe 4 Refrigerant introduction pipe 5 Refrigerant discharge pipe 6 Crystallization solution discharge pipe P1 Refrigerant introduction pump P2 Refrigerant discharge pump DESCRIPTION OF SYMBOLS 11 Solution tank 12 Belt conveyor type crystallizer 13 Cooling jacket 14 Belt 15 Crystal scraper

Continued on the front page (72) Inventor Masami Akiyama 1 Konica Stock Company, Sakuracho, Hino-shi, Tokyo In-house

Claims (3)

[Claims] 1. A crystallization apparatus for performing crystallization by cooling, wherein the crystallization apparatus has a cooling body having a refrigerant introduced therein, and the cooling body has variability and mobility. 2. The crystallization apparatus according to claim 1, wherein the cooling body is deformed or vibrated by changing an inflow condition of an introduction means for introducing a refrigerant into the cooling body. 3. The crystallization apparatus according to claim 1, wherein the cooling body into which the refrigerant has been introduced repeatedly expands and contracts continuously or intermittently.