Effect of operating parameters on temperature and concentration polarization in vacuum membrane distillation process

Membrane distillation is a process combining thermal and membrane technology, which uses the vapor pressure difference as driving force because of the temperature difference. Of the MD configurations, VMD can achieve high flux due to the application of vacuum. This paper analyzes operating parameters (vacuum pressure, feed flow rate, and feed concentration) that affect permeate flux in a modified design VMD system vacuum multi-effect membrane distillation (V-MEMD). The study investigated the most suitable operating parameters that would enhance the performance of V-MEMD system at high salinity (1-4M of NaCl) with a moderate bulk temperature of 60 degrees C. The result of this study showed that vacuum pressure is the most influential factor of the selected, and the effect of temperature polarization is more dominant to permeate flux than concentration polarization. Above this, the high-salinity solution can be treated by V-MEMD system because it does not affect the permeate total dissolved solid and flux. A dominant reduction ratio of vapor pressure was observed even at a low ratio of temperature polarization.