Desalination by Membrane Distillation: A Parametric Study

Abstract

Membrane distillation was investigated as a possible technique for desalination. An air-gap module with built-in condensing surface was used for conducting experiments on polyvinylidene fluoride flat membrane sheets. The feed stream tested was artificial seawater. The quality of the permeate, quantified by conductivity measurements, and the permeate flux were monitored as the feed temperature, feed flow rate, cooling temperature, and cooling water flow fate were varied. The effect of the distance between the membrane and condensing surface was investigated by adjusting the air gap within the module. A mathematical model incorporating temperature and concentration polarization effects was developed and validated on the experimental data. Good agreement between experimental and predicted values was obtained.