Desalination, Vol.433, 89-93, 2018
Water desalination by pervaporation - Comparison of energy consumption
The most common desalination technology is based on reverse osmosis, which uses semi-permeable membranes and pressures from 5.5 MPa to 6.8 MPa in order to overcome the osmotic pressure. The lowest achievable energy consumption of RO is 2 kWh/m(3). The other viable methods of desalination include membrane distillation and pervaporation. Each of these techniques has certain advantages and disadvantages but in terms of energy consumption pervaporation seems particularly promising. Over the past few years, desalination performed with the help of pervaporation has been widely investigated. In this study, desalination experiments were carried out with a commercial membrane. The salt concentration and the feed solution temperature were varied between 0.8% and 7.0% and between 40 degrees C and 70 degrees C, respectively. The experiments helped determine the desalinated water flux and the salt rejection factor. In addition, differences in enthalpy and Gibbs free energy, representing the theoretical energy consumption, were estimated in the raw water/feed and the feed/permeate systems. For the purpose of comparing the energy consumption, three desalination techniques were considered: RO, PV and MD.