Abstract
Closed-loop pressure retarded osmosis (CL-PRO) process has been used for generating renewable energy from osmotic power by using a semipermeable membrane. In this research, the sodium chloride NaCl solution with a specific molar concentration was employed as the draw solution DS, while feed solution FS was tap water. The laboratory-scale system was utilized for evaluating the CL-PRO process performance of a cellulose triacetate hollow fiber CTA-HF module within a broad range of the operational conditions such as draw solution concentration (0.1 - 0.5 M), applied hydraulic pressure difference (0 - 8 bar), flow rate of the draw solution (0.8 - 2.8 L/min), and the temperature of the DS and FS (20 - 35 C). The effect of these operational parameters was investigated on the power density and the flux of permeated water. According to the experimental results, the power density and the flux of the permeated water increased with increasing the draw solution concentration, the flow rate of the draw solution, and the temperature of solutions. By increasing the applied hydraulic pressure on the shell-side of hollow fiber membranes (draw solution side), the water flux decreased while the produced power density increased. The maximum power density and the flux of permeated water of 0.5 M NaCl DS were approximately 0.94 W/m2 and 4.27 LMH respectively, which occurs at 8 bar hydraulic pressure.