Flow and fouling visualization in modules having multiple multichannel membranes

Journal of Membrane Science, vol. 732, pp. 124205

Abstract

Interest in multichannel membrane modules as robust alternatives to single-bore hollow fiber membranes is growing, yet their complex hydrodynamic behavior remains underexplored, particularly in densely packed configurations. In this study, we employed magnetic resonance imaging (MRI) to investigate flow distributions and fouling dynamics in multichannel membrane modules containing one, seven, and nineteen fibers. Under forward permeation at 100 LMH, we observed marked inhomogeneities on both the shell and lumen sides, which became more pronounced at higher packing densities and towards the module outlet. Notably, jet-like flow streams, reverse flows, and localized recirculation zones developed, creating substantial deviations in velocity profiles along the module axis. Fouling experiments with silica particles revealed a disproportionately reduced contribution of inner bore channels, highlighting the vulnerability of certain lumen regions to filter cake formation. Backwashing at 100 LMH and 200 LMH partially alleviated these blockages but also redistributed filter cakes to previously open bore channels. Despite some channels showing improved flux recovery, a subset of fibers remained inaccessible to cleaning due to preferential flow pathways that bypass clogged regions. These findings have important consequences for module design and operation. They underscore the need for precise control over packing density, fiber spacing, and shell connection configuration to minimize maldistribution and optimize overall hydraulic performance. Going forward, deeper investigations into reverse flow phenomena and localized pressure gradients will be critical in guiding next-generation module architectures and fouling mitigation strategies, ultimately enhancing the reliability and efficiency of membrane-based water treatment processes.

Authors 4

1. Denis Wypysek Aachen Chemical Process Engineering DWI - Leibniz Institute for Interactive Materials

   DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering (AVT.CVT), RWTH Aachen University, Forckenbeckstraße 51, Aachen, 52074, Germany

   DWI - Leibniz-Institute for Interactive Materials, Forckenbeckstraße 50, Aachen, 52074, Germany

2. Simon Wennemaring Aachen Chemical Process Engineering

   RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering (AVT.CVT), RWTH Aachen University, Forckenbeckstraße 51, Aachen, 52074, Germany

3. Antoni Dudij Aachen Chemical Process Engineering

   RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering (AVT.CVT), RWTH Aachen University, Forckenbeckstraße 51, Aachen, 52074, Germany

4. Matthias Weßling corresponding Aachen Chemical Process Engineering DWI - Leibniz Institute for Interactive Materials

   DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering (AVT.CVT), RWTH Aachen University, Forckenbeckstraße 51, Aachen, 52074, Germany

   DWI - Leibniz-Institute for Interactive Materials, Forckenbeckstraße 50, Aachen, 52074, Germany