Axial flow hollow fiber forward osmosis module analysis for optimum design and operating conditions in desalination applications

In this article, a mathematical model is developed for axial flow hollow fiber (HF) forward osmosis (FO) module and validated with unsteady-state FO experimental data of NaCl-H2O system. A maximum of 0.7 and 12% deviation in draw solution (DS) and feed solution (FS) concentration shows a good agreement between experimental results and model outputs. Simulations were carried out at various module length and operating conditions to analyze their effects on permeate flow rate and power consumption. Based on the simulation results, a multi-objective optimization (MOO) was formulated to get optimal Pareto between FO water flux and power supplied to the pump by considering the module length, DS and FS pressure and flow rate as decision variables. The optimization analysis revealed the exponential behavior of power consumption with respect to the permeate flow rate. Finally, a procedure to optimize the FO plant performance using MOO optimal Pareto is presented. (C) 2020 Elsevier Ltd. All rights reserved.