The Maltitol Purification And Concentration By Nanofiltration

The experiment adopts nanofiltration membrane L and E to purify themaltitol. Membrane E plays the role of removing the multi-sugar alcohol inmaltitol, and membrane L removing sorbitol as well as water. The experi-mental result shows, in the range of 0.8-1.5MPa, with the improvement ofthe pressure the permeable flux of membrane L becomes stead little by little.Otherwise, the permeable flux of membrane E is in direct proportion to pre-ssure. Through the obstruction model, it is easy to find the membrane Lnanofiltration process is determined by the resistance of both polarizationlayer and the membrane. The membrane E nanofiltration process is onlydetermined by the resistance of the membrane. With the increment ofoperation pressure, the rejection of both two membranes increases. Therejection and permeable flux both increase with the growth of cycle flowand finally turn out to be steady. Meanwhile, our experiment also has aresearch on the relationship of materiel concentration, flux, and rejection.From the experiment we can see with the increment of material concentr-tration, both two membranes flux and rejection decrease. Otherwise, bothpermeating flux and dray matter of filtration are increased with the temper-rature enhanced, and membrane swelling should not be ignored when thetemperature exceed 40oC. According to the experiment, we have drawn thebest operating condition of the maltitol purification is: to membrane L, theoperating condition is 1.2～1.5MPa, the cycle flux is 60～80L/h. To memb-rane E, the operating condition is 1.5MPa, the cycle flux is 40～60L/h. In addition, we have also carried on research to the cleaning and rec-ycle of the membrane. we have drawn the best operating condition of thecleaning and recycle. Gelatinous layer can be effectively eliminated by wa-shing in positive direction scouring with hot water for 30 minutes, if wash-ing flux is from 100L/h to 140L/h, under normal pressure, and at 40oC.