降膜结晶分离技术实验研究

采用萘－硫茚物系对新型高效降膜结晶技术的分离提纯机制进行了实验研究．考察了管外降膜结晶过程中结晶时间、料液流量、冷却水初始进口温度、冷却水降温速率及原料浓度对分离提纯效果的影响．实验发现降膜结晶过程中晶层生长并不完全是光滑界面的生长，而在某些条件下表现为粗糙界面的生长，即生长过程在某些条件下表现为两相区界面的生长．进一步对辅助提纯－发汗过程的工艺参数—发汗时间、发汗初始浓度的影响进行了实验研究．实验结果可用于降膜结晶传热传质机理的数值模拟．

EXPERIMENTAL STUDY ON FALLING FILM CRYSTALLIZATION PROCESS

Experimental study on the falling film crystallization process is carried out by using a binary system of naphthalene-thionaphthene as raw material The influence of various process parameters including crystallization time, flow rate of melt, initial inlet temperature of cooling water, temperature-decreasing rate of cooling water and melt concentration on falling film crystallization is discussed for falling film crystallization taking place on the external surface of a central tube It is found that the crystal surface is not all smooth and the crystallization process proceeds with rough interface and mushy zone under certain conditions Furthermore, the purification effect of sweating process including sweating time and starting crystal purity are explored experimentally The results provied an important data base for understanding the mechanism of heat and mass transfer in falling film crystallization and for further industrial application of falling film crystallization process