Equipment for preparing high pure organic matter by fusion-crystallization method

Abstract

A device for preparing high-purity organic substance by fusion crystallizing method is a tower structure which is divided into upper cooling-crystallizing segment, middle separating-purifying segment and lower crystal fusing segment. Its tower body is inclined and is composed of casing consisting of intersected two cylinders, heater and parallel engaged two spiral stirrers.

Description

technical field [0001] The invention belongs to a device for preparing high-purity organic matter, in particular to a device for preparing high-purity organic matter by adopting a melting crystallization method. Background technique [0002] In recent years, with the rapid development of pharmaceutical industry, food industry, fine chemical industry, polymer material engineering and other industries, the international demand for high-purity organic substances is increasing, especially for optically active substances used as pharmaceuticals, the purity requirements are extremely high. high. Melt crystallization, as a separation and purification method with high efficiency and low energy consumption, has been widely used in industrial production. [0003] Because the tower crystallizer can complete the crystallization-washing-recrystallization operation at the same time, it is a device commonly used in industry to purify organic matter by melting c...

AI Technical Summary

Problems solved by technology

The weak point of this patent is: 1) the inner wall of the crystallization section tower shell is easy to crystallize scale

Since the shell of the crystallizer is cylindrical, there is a stirring dead zone between the double helix stirrer and the inner wall of the tower body. The existence of the dead zone makes the crystals precipitated on the inner wall of the tower shell in the crystallization section unable to be stirred by the double helix in time. The device is scraped off, so that a crystal layer appears on the inner wall of the tower shell here. Even if the appearance of the crystal layer does not affect the solid-liquid two-phase flow in the tower, it will also affect the heat transfer efficiency and production capacity of the device. After long-term operation, When the crystal bed grows to a certain thickness, the crystallization section will be blocked, so that the device cannot continue to operate; if the crystal bed is scraped loose by the double helix stirrer and falls from the tower wall, the double helix stirrer may be stuck, Make the device unable to continue to operate or affect the effect of washing and purification

At the same time, intermittently scraping off the crystal blocks from the inner wall of the tower shell will destroy the established solid-liquid two-phase balance, making the crystallization tower unable to operate continuously and stably

2) Difficult to achieve stable countercurrent flow of solid-liquid two-phase

For most organic systems, the density difference between the solid and liquid phases is very small. Furthermore, in the process of melting and crystallization, the crystals are formed in their own molten liquid, and the crystal particles are very small. Under the condition of agitation, The crystalline particles are always dispersed in the surrounding molten liquid, and it is difficult to be transported upward by the double helix agitator, so the stable countercurrent flow of the solid-liquid two-phase cannot be effectively realized. To maintain the stable countercurrent flow of the solid-liquid two-phase, the It is necessary for the crystal particles to grow to a certain size, so the crystallization time increases. The increase in crystallization time not only increases energy consumption, but also affects the production capacity of the device, and increases the probability of crystal scars appearing on the inner wall of the crystallization section tower shell

In addition, due to the smaller solid-liquid contact area of ​​large-grained crystals, the purification effect is lower than that of small-grained crystals.

3) It is difficult to prepare high-purity organic matter

As mentioned above, in order for the device described in this patent to operate continuously and stably, the crystal particles must grow to a certain size, but the sweating mechanism of purification cannot be fully utilized in this way, so that the purification mainly relies on countercurrent washing, so it is difficult to obtain 99.99% High-purity organic matter above

4) Increased energy consumption and increased operational difficulty

Transporting large-grained crystals upwards increases power consumption on the one hand, and puts forward strict requirements on the stirring rate on the other hand, which increases the difficulty of operation. If the stirring rate is too low, the crystals cannot be transported upwards to achieve solid-liquid two-phase countercurrent flow. If it is too high, the contact time between solid and liquid phases will be shortened, and a good washing effect will not be achieved.

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