A conceptual membrane arrangement design in the high pressure vessel for seawater desalination

Abstract

The wide applications of Reverse Osmosis (RO) membranes in seawater desalination and various industrial processes have encouraged researchers and scientists to investigate the phenomena of water and salt diffusion through the membrane. Typically, the high pressure RO membrane vessel is loaded with membrane elements having the same flux and salt rejection rate. It has been conceived that when different types of RO elements are loaded into the pressure vessel in a special arrangement according to their permeability and salt rejection rate, this arrangement has the potential for reducing the energy consumption of the RO plant. A conceptual design is introduced here to describe this new idea. The effects of feed salinity and temperature were investigated in this paper using the ROSA Filmtec membrane design software. A two pass membrane treatment process was designed for desalting seawater at different salinities varied from 35000 ppm to 43000 ppm. The results showed a net energy saving from 2.5% to 3% (depending on the feed salinity) could be achieved. The effect of the feed temperature was also investigated and the new design was found to be more energy efficient.