Hybrid Membrane Inter-Stage Design for RO Seawater Desalination System
Energy-saving design of seawater reverse osmosis desalination(SWRO)system is of great significance for reducing the cost of water production and promoting the application of seawater desalination.Hybrid membrane inter-stage design(HID)is a novel method for designing reverse osmosis system,whose features are arranging different types of membrane elements inside the same pressure vessel,optimizing the overall performance through their complementation.In this study,software simulation was employed to investigate the performance differences of membranes from four mainstream brands,namely,DuPont,LG,Toray,and Hydranautics,in terms of water quality,energy consumption and flow distribution.It was found that Toray membranes exhibited outstanding performance in balancing flow and energy saving efficiency.Then,the impacts of temperature and configuration ratio on the performances were further explored for Toray membranes.The results showed that temperature was an important factor for HID.Specifically,in the northern part of China where the seawater temperature was low and the water qualities vary less,the energy-saving effect of HID was more prominent,with the efficiency up to 9%,and the flow balance effect significantly enhanced.