Hybrid RO MSF Desalination: Present Status and Future Perspectives

Hybrid RO MSF desalination system combines the advantages of the high desalting performance of distillation processes and the lower energy requirement of membrane processes. It allows better match between power and water requirements and enables better utilization of the power generated from MSF into the RO. Hybrid RO and MSF system will yield some economical and technical advantages. It also has potential advantages of a low power demand, improved water quality and possible lower running cost as compared to stand-alone RO or MSF plants. Hybrid RO MSF can lead to an optimized feedwater temperature of the RO plant since it is possible to use cooling seawater from the reject stage of the MSF plant as feed to RO plant. Higher feed temperature is advantageous for the RO plant since water flux of the membrane is about 2.5 % higher per degree of temperature rise at constant pressure. This allows an increase in the RO productivity. The rate of water permeation through the membrane increase as the feed water temperature increases since the viscosity of the solution is reduced and higher diffusion rate of wate