Technical and Economical Comparison Between Large Capacity Multi Stage Flash and Reverse Osmosis Desalting Plants

In the course of evaluating the unit cost of desalted water by either the predominant multi stage flash (MSF), and its competitor reverse osmosis (RO) desalting systems, a quantitative comparison of the equipment used was conducted. The chemical and energy consumptions are also compared for both systems. More expensive materials and more energy are consumed in the MSF system than in RO so that the unit cost of seawater desalted by the RO system is lower than that obtained by the MSF system. Moreover, prospects for lower cost by the RO system exist by developing a more efficient energy recovery system and reducing the cost of the membranes. It is believed that the present cost of membranes is much higher than the real manufacturing cost.