US 6,145,340 A · Process for fractional crystallization of substances, a crystallizer suitable for working the process, and use of the process

Abstract

In the process according to the invention for fractionating substances, particularly paraffins, oils, fats and waxes, which, when crystallized, have poor adhesion to the substantially vertical crystallization surfaces (39) of a crystallizer, screen-like supporting structures, e.g. perforated metal sheets (31) bent in a zig-zag, are disposed between the crystallization surfaces (39) of a crystallizer. The crystals (51) becoming detached from the crystallization surfaces (39) during the sweating phase are left suspended in horizontal strips in the triangular zones (41) on the perforated sheet (31) and remain in thermal contact with the crystallization surface (39) and sweat out the liquid phase (55). The mother liquor (55) drips off, in some cases also between the crystals (51) and the crystallization surface (39), with the result that drip channels are melted by the heated mother liquor and thus opened.

Claims20

Dependent claims

A process for a fractional crystallization of substances

comprising
filling 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, and
during 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, while
permitting liquid fractions to flow through the screen-like supporting structure.

4 more elements

Dependencies are inferred from the claim text.

Process for fractional crystallization of substances, a crystallizer suitable for working the process, and use of the process

Life of this patent

Process for fractional crystallization of substances, a crystallizer suitable for working the process, and use of the process

Life of this patent

Abstract

Claims20