Studies into the mass transfer and energy consumption of commercial feed spacers for RO membrane modules using CFD: Effectiveness of performance measures

Abstract

Different approaches have been reported in the literature that aim to improve the performance of reverse osmosis (RO) desalination plant operations, attempting to make the desalination process more efficient. This study investigates the performance of four commercial feed spacers for spiral wound reverse osmosis modules by considering energy consumption and production capacity, as well as their combination, through a previously proven approach to computational fluid dynamics (CFD) modelling. Among the performance measures studied, SCE (spacer configuration efficacy), SPC (specific power consumption) and Pn (power number) showed a high level of predictability (R2 = 0.998, 0.994 and 0.994, respectively) through power law correlations of Re with two spacer-dependent parameters. Of the four commercial spacers investigated, the DelStar Technologies Naltex N05013_90HDPE-NAT (“90 HDPE”) spacer has been ranked as the best or second best based on multiple performance measures over the flow range Re = 50–100. Furthermore, the very weak response to flowrate changes observed for 90 HDPE, based on pressure loss, SPC, Pn, Sh and SCE measures, indicates the prospects for energy savings. SPMP' a modified definition of SPMP (Spacer Performance Ratio), shows no consistent response to flow variations for the spacers studied.