Hole-Type Spacers for More Stable Shale Gas-Produced Water Treatment by Forward Osmosis

Abstract

An appropriate spacer design helps in minimizing membrane fouling which remains the major obstacle in forward osmosis (FO) systems. In the present study, the performance of a hole-type spacer (having holes at the filament intersections) was evaluated in a FO system and compared to a standard spacer design (without holes). The hole-type spacer exhibited slightly higher water flux and reverse solute flux (RSF) when Milli-Q water was used as feed solution and varied sodium chloride concentrations as draw solution. During shale gas produced water treatment, a severe flux decline was observed for both spacer designs due to the formation of barium sulfate scaling. SEM imaging revealed that the high shear force induced by the creation of holes led to the formation of scales on the entire membrane surface, causing a slightly higher flux decline than the standard spacer. Simultaneously, the presence of holes aided to mitigate the accumulation of foulants on spacer surface, resulting in no increase in pressure drop. Furthermore, a full cleaning efficiency was achieved by hole-type spacer attributed to the micro-jets effect induced by the holes, which aided to destroy the foulants and then sweep them away from the membrane surface.

Numerical analysis of permeate flux in reverse osmosis by varying strand geometry

“…However, the exceptionally elevated pressures lead to remarkably high operational costs. The considerable energy utilization of the membrane desalination process for water purification has persuaded researchers to investigate different spacer designs using computational techniques for minimizing energy consumption per unit of permeate 6 – 8 . The desalination processes are also of economic benefits minimalizing the feed and brine volumes 9 .…”

Study of Turbulence Promoters in Prolonging Membrane Life

“…Numerous studies have been undertaken on the preparation of antifouling membranes [21][22][23][24], but reducing membrane fouling from the perspective of membrane modules remains less explored. In recent years, studies have also proposed changing the hydraulic conditions in the membrane chamber using a turbulence promoter to reduce concentration polarization and increase the mass transfer rate [25,26]. Computational fluid dynamics (CFD) is a tool that can be used to intuitively study the fluid flow, particularly the local micro-scale fluid flow phenomenon.…”