Systematic approach for draw solute selection and optimal system design for forward osmosis desalination

A systematic approach is proposed to find the optimal draw solute and the optimal system for forward osmosis (FO) desalination. Selection of a draw solute and its concentration mainly decides the water flux through FO membrane, as well as the energy requirement for draw solute recovery, i.e. the economy of FO desalination. The proposed approach selects 7 candidate compounds by screening 4058 compounds in OLI and ASPEN chemical databases. Subsequently, the membrane and distillation column processes are designed and optimized for each draw solute by establishing a cost minimization model. Finally, economies of the optimal systems for candidates are compared to find the most competitive draw solute. The proposed method will contribute to designing commercially viable FO desalination systems.

► Systematic approach to find the optimal draw solute is proposed. ► Property database of 4058 compounds is established. ► Draw solute candidates have been selected by a hierarchical screening method. ► A cost minimization problem integrating operation and investment costs. ► The proposed approach provides an evaluation tool to compare draw solute candidates.