Membrane distillation for the concentration of raw cane-sugar syrup and membrane clarified sugarcane juice

Abstract

Membrane Distillation (MD) is a process being investigated the world over as a low cost energy saving alternative to conventional separation processes such as distillation and reverse osmosis. MD has a wide range of benefits such as a 100% (theoretical) rejection of ionic species, macromolecules, colloids, cells and other non-volatiles, lower operating pressures, reduced chemical interaction between membrane and process solutions, less demanding membrane mechanical properties and reduced vapour spaces. This process is ideally suited for the concentration of aqueous streams such as fruit juice and sugar solutions. Clarified cane sugar solution (20°Brix) obtained from the sugar mill, immediately after the Dorr filtration was subjected to membrane distillation, whereby the sensible heat from this stream was used to remove water as vapour through a hydrophobic polypropylene membrane. The influence of cross-flow rate and continuous water addition on flux was evaluated.