Sugar refining process by coupling flocculation and crossflow filtration

Raw cane sugar solution at 50 brix was purified by combining flocculation with a cationic polymer and crossflow micro/ultrafiltration using tubular mineral membranes of porosities ranging from 0.2 mu m to 15 kDa. The pilot rests indicated that the coupling of these two processes led successfully to a permeate decolorization of 50% at a 65 l h(-1) m(-2) permeate flux with the 300 kDa m membrane which was found to be the most promising one. This result is considerably improved compared to the 39% decolorization rate and the 25 l h(-1) m(-2) flux given by the 15 kDa membrane alone. ion exchange resin decolorization tests demonstrated the benefit of flocculation and ultrafiltration pretreatments on sugar liquor quality. (C) 1997 Elsevier Science Limited.