Modification and operational stability evaluation of a miniaturized reciprocating-switcher energy recovery device for SWRO desalination system

The self-boosting energy recovery device (SB-ERD) integrated with the booster pump function can reduce the power consumption of small and medium-sized seawater desalination systems. Nevertheless, for SB- ERD, the flow rate and pressure pulsation of HP brine and nonadjustable capacity are presented in the operation process, affecting its further application in seawater reverse osmosis (SWRO) systems. In this paper, the SB-ERD was modified to a miniaturized reciprocating-switcher energy recovery device (MRS-ERD). Then a SWRO experimental test platform equipped with MRS-ERD was built to evaluate operational performance. The experimental results show that the pressure pulsation amplitude of HP brine is maintained at 0.20 MPa, and the flow rate pulsation amplitude is kept only between 0.153 and 0.186 m(3)/h. At design capacity, the pressure pulsation ratio of HP brine is reduced by 2.41% compared with SB-ERD, and the flow rate pulsation ratio is only 1.5%, which is 4.05% lower than that of SB-ERD, revealing excellent operational stability. Furthermore, under 5.0 MPa and 80%-130% of the design capacity (12 m(3)/h), the MRS-ERD can run with a constant efficiency above 96.33% and a leakage ratio of 1.3%-2.7%, which is competitive in commercial products. Hence, MRS-ERD exhibits huge application prospects in small and medium-sized SWRO systems.