Pilot tests of fluid-switcher energy recovery device for seawater reverse osmosis desalination system

Energy recovery devices (ERDs) reduce the power consumption of seawater reverse osmosis (SWRO) systems greatly by recovering the pressure energy in the retentate brine. There are basically two types of ERD in the market, the isobaric type and the centrifugal type. Of which the former achieves rapid progress and holds the leading position in recent years due to its high efficiency. In this article, a pilot-scale fluid-switcher ERD (FS-ERD, isobaric type) was designed and tested under the capacity of 30 m3/h and the operating pressure of 6.0 MPa. The fluid dynamics performances and the efficiency of the device were studied and evaluated. The demonstration shows that the FS-ERD presents good stability with negligible pressure pulsations and high energy recovery efficiency of about 95.9%, which paves the way for the application of FS-ERD in SWRO plants.