Cane sugar crystallization using submerged vacuum membrane distillation crystallization (SVMDC)

The performance of Submerged Vacuum Membrane Distillation and Crystallization (SVMDC) for cane sugar concentration and crystallization was investigated in this study. Using hollow fiber membrane, the effect of operation parameters, such as feed concentration, feed temperature, and feed agitation were evaluated against the permeate flux. Following the operation parameters optimization, long-term SVMDC tests were performed using cane sugar model solution and raw sugarcane juice as the feed. Porous fouling layer was formed in test using cane sugar model solution which led to membrane fouling and wetting. However, sugar crystals were successfully formed in this test, despite under-saturated final feed concentration of 73.3°Brix. This indicated the occurrence of heterogeneous crystallization in the feed solution, that was induced by the sugar crystals detached from the membrane surface. In test using raw sugarcane juice as the feed, extremely low flux was observed due to the presence of impurities. However, membrane wetting did not occur as the implication of weak drag force occurred due to the low permeate flux. In this test, there was no observable crystal formed as the final feed concentration was much lower than the saturation concentration. In addition, the impurities hindered the interaction of sucrose molecules and disrupted crystal growth.