Arch-type feed spacer with wide passage node design for spiral-wound membrane filtration with reduced energy cost

Abstract

A novel feed spacer for spiral-wound membrane modules is proposed. Based upon a continuous arch-type streamline frame two feed spacers with different node designs were constructed. In the first, Arch-Hole, two elliptic cylinders form a node zone with a passage. The other, named Arch, has a solid node. Their hydrodynamics, fouling and filtration performance were compared with a commercial design. This was a classic net-type spacer with nodes of relatively substantial size. All three were manufactured using 3D printing. Computational fluid dynamics simulation showed that the Arch-Hole design gives a more uniform velocity distribution with fewer dead zones. Subsequent evaluation of this design indicated less foulant accumulation as confirmed by optical coherence tomography and the evolution of channel pressure drop. Measured adenosine triphosphate and total organic carbon values for the module with this spacer were substantially lower than the corresponding values associated with the commercial design. Crucially with the Arch-Hole design, flux values remained higher than for the other two designs. Thus use of this spacer would minimize both capital and operational costs. Compared to the commercial one, use of the Arch-Hole design would reduce the energy cost of filtration significantly beyond the 69 % found for the application considered herein.