Cooling crystallization applied to the “extract” of a chromatographic separation process (SMB) of beet raw juice

The idea that the current technology of beet sugar manufacture needs great changes in order to make the technology itself more environmentally compatible is gaining more and more ground. Such changes concern energy and water saving, gaseous emissions, and, in particular, the removal of limestone consumption and, as a consequence, of waste materials, i.e. carbonation sludges. The research of alternative solutions dictates the use of new technologies including membrane separation processes, chromatography and cooling crystallization.

Beet raw juice has been microfiltered without the traditional calcocarbonic purification step, softened and put through a chromatographic separation process using a SMB (Simulated Moving Bed) pilot plant. The fraction rich in sugar, “extract”, has been crystallized through subsequent cooling crystallization steps with the purpose of obtaining commercial white sugar. The results of the trials, which emphasize the characteristics of the sugar obtained and the crystallization yields, are presented and discussed. The morphology of crystals obtained from the different crystallization steps is particularly pointed out. In fact, the peculiar composition of the non-sucrose fraction present in the “extract” promotes the formation of crystals showing particular shapes.