Purification of naphthalene from eutectic mixture by continuous column crystallization

−To obtain highly purified naphthalene, a column crystallizer was employed and operated in the continuous multistage countercurrent fractional mode. The principles and characteristics of the process are introduced. A large amount of experimental work has been done on the crystallization process in a D=50 mm×1,350 mm column. The effects of operation conditions including the composition of feed, reflux ratio, stirring speed and the bed height of crystal on crystallization were systematically studied. The experiments showed that over 99.0% of the purity of product can be easily achieved in such conditions: feed composition among w=85.462-95.894%, reflux ratio among 1.42-4.04, the crystal bed height among 400-900 mm. The purity of product even reaches 99.996% in experiment.