Patent ID: 6145340
Filing Date: 2000-11-14
Classification: B01D

Abstract:
A process for a fractional crystallization of substancescomprisingfilling a mixture of substances into a crystallizer, the crystallizer having vertical or inclined crystallization surfaces, said mixture containing (i) a substance which, when crystallized, does not adhere sufficiently to the vertical or inclined crystallization surfaces of the crystallizer, and (ii) fractions having a lower melting point than said substance,cooling said crystallization surfaces and thus, cooling the mixture and crystallizing said substance in layers on said crystallization surfaces,discharging remaining liquid from the crystallizer,heating said crystallization surfaces and thus sweating said crystallized substance, andduring said sweating, retaining crystals on a screen-like supporting structure disposed between the crystallization surfaces, said crystals due to their weight and their insufficient adhesion to the crystallization surfaces become detached from the crystallization surfaces, whilepermitting liquid fractions to flow through the screen-like supporting structure.