Enhanced Performance Dual Stage Pressure Retarded Osmosis

Abstract

Abstract A dual stage PRO process has been proposed for power generation from a salinity gradient across a semi-permeable membrane. Both closed-loop and open-loop dual stage PRO system were evaluated using 2 M NaCl and Dead Sea as draw solutions, whereas the feed solution was either fresh water or seawater. The impact of feed salinity gradient resource and feed pressure on the net power generation and water flux were evaluated. DSPRO can be combined with desalination plant using seawater brine as the draw solution either in closed-loop or open-loop. This hybridization has multiple applications such as reducing the impact of discharging concentrated brine to sea, energy storage, and increase the recovery rate of the desalination. Power generation by DSPRO will reduce the energy consumption by the desalination processes. Waste heat from power plants can be used for the regeneration of the draw solution in the closed-loop DSPRO. Process modelling has been performed and shown promising results for DSPRO application for power generation.