Taguchi Method in the Evaluation of Vacuum Membrane Distillation in Water Desalination

摘要

Taguchi method has been applied to evaluate the effects of operational parameters on the efficiency of vacuum membrane distillation (VMD) in the desalination of water. It was observed that permeate increases with an increase in feed temperature and vacuum pressure. However, feed salt concentration adversely affected the amount of the collected permeate due to the reduction of vapour pressure as a result of the presence of the solute in water. Flow rate, however, could only increase the permeate if it was increased from 37.5 to 50 ml/s. Any further increase in flow rate to 100 ml/s, negatively lowered the permeate due to the limited feed/membrane contact time. We observed that at very high salt concentration (300 g/l) the permeate reduces accordingly, highlighting the fact that VMD should be used with care due to the presence of membrane fouling and/or other simultaneous flux-lowering effects present at concentrated feeds.