Evaporative crystallization process is a common operating unit in pharmaceutical and chemical processes. It is widely used in the production process of almost all crystalline drugs.
Evaporative crystallization commonly used in enterprises today mainly includes thermal convection type and forced circulation type. The above two types of evaporative crystallizers are mostly crystallized by forced external circulation. The principle of the evaporator is that the material solution is heated by the pump under the action of the pump and evaporated in the evaporator. After such a plurality of cycles, after the solution concentration exceeds the solubility at the temperature, the solute precipitates crystal, in this state. The solution in which the crystal has appeared continues to be repeatedly heated by the action of the pump. During the evaporation process, until a large amount of crystals appear, the solution becomes a very thick suspension of the crystal can not be recycled, because many varieties of the drug are heat sensitive, and the hardness of the crystal is high, the solution is very viscous after reaching saturation state. The fluidity is greatly reduced. Therefore, the problems in the use of the above-mentioned commonly used evaporators are poor quality of the drug product, high evaporation temperature in the later stage, low utilization of the liquid material, increased energy consumption, and final product yield. Low, and the equipment is worn due to the erosion of a large number of crystals, the service life is short, and the metal particles washed down contaminate the drug, so that the metal content of the drug is increased, and the purity of the product is lowered.