Separation Science and Technology, Vol.31, No.13, 1859-1875, 1996
Separation of Organics by Melt Crystallization with Direct-Contact Cooling
The application of direct contact cooling to melt crystallization for the separation of organics was examined. Three types of immiscible coolants for gas, liquid, and liquefied gas were investigated. The crystals produced by this direct contact cooling techniques were of good quality, significantly larger than those by scraped-surface crystallizers. The content of the impurity included in the crystals was correlated with mass ratio of suspended crystals, For upgrading the crystals, three kinds of methods were studied, Direct contact melting using warm coolants was found to be the most efficient, From comparison between effective distribution coefficients obtained before and after washing, the inner side of crystals was found to be very pure and any impurity was concentrated in the outer layer of crystals. Crystals were found to be contaminated by adhering residual melt in this melt crystallizer with direct contact cooling. Performance for separation of organics was more efficient than that of film crystallization in terms of purity of crystal and production.