Abstract
Regarding practical application of a reverse electrodialysis （RED） system using salinity gradient energy （SGE）, it would be appropriate to use seawater brine （BR） from a SWRO desalination plant instead of seawater （SW） due to high salinity. In this study, we have evaluated the power generation performance of a pilot-scale RED stack with a total effective membrane area of 180 m2 using Model BR（90 mS/cm NaCl） and real river water （RW） as high and low salinity feed solutions, respectively. Model SW（50 mS/cm NaCl） was also used as a high salinity feed solution for comparison. The maximum gross power output of the RED stack increased with increasing current and then reached a maximum of 1.42 W/m2（256 W） and 0.93 W/m2（169 W） using BR and SW as the high salinity source with the energy conversion efficiency of about 15 ％ and 20 ％, respectively. The results indicate that a RED system using the stacks in this study generates 452 kW of gross power output using 60,000 m3/day of all discharged brine from the desalination center in Okinawa.
