Print Email Facebook Twitter Porosity of spacer-filled channels in spiral-wound membrane systems Title Porosity of spacer-filled channels in spiral-wound membrane systems: Quantification methods and impact on hydraulic characterization Author Siddiqui, A (King Abdullah University of Science and Technology) Lehmann, S (LANXESS BU Liquid Purification Technologies) Haaksman, V.A. (TU Delft BT/Environmental Biotechnology) Ogier, J. (LANXESS BU Liquid Purification Technologies) Schellenberg, Carsten (LANXESS BU Liquid Purification Technologies) van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology) Kruithof, J. C. (Wetsus, Centre for Sustainable Water Technology) Vrouwenvelder, J.S. (TU Delft BT/Environmental Biotechnology; King Abdullah University of Science and Technology; Wetsus, Centre for Sustainable Water Technology) Date 2017-08-01 Abstract The porosity of spacer-filled feed channels influences the hydrodynamics of spiral-wound membrane systems and impacts the overall performance of the system. Therefore, an exact measurement and a detailed understanding of the impact of the feed channel porosity is required to understand and improve the hydrodynamics of spiral-wound membrane systems applied for desalination and wastewater reuse. The objectives of this study were to assess the accuracy of porosity measurement techniques for feed spacers differing in geometry and thickness and the consequences of using an inaccurate method on hydrodynamic predictions, which may affect permeate production. Six techniques were applied to measure the porosity namely, three volumetric techniques based on spacer strand count together with a cuboidal (SC), cylindrical (VCC) and ellipsoidal volume calculation (VCE) and three independent techniques based on volume displacement (VD), weight and density (WD) and computed tomography (CT) scanning. The CT method was introduced as an alternative for the other five already existing and applied methods in practice. Six feed spacers used for the porosity measurement differed in filament thickness, angle between the filaments and mesh-size. The results of the studies showed differences between the porosities, measured by the six methods. The results of the microscopic techniques SC, VCC and VCE deviated significantly from measurements by VD, WD and CT, which showed similar porosity values for all spacer types. Depending on the maximum deviation of the porosity measurement techniques from −6% to +6%, (i) the linear velocity deviations were −5.6% and +6.4% respectively and (ii) the pressure drop deviations were −31% and +43% respectively, illustrating the importance of an accurate porosity measurement. Because of the accuracy and standard deviation, the VD and WD method should be applied for the porosity determination of spacer-filled channels, while the CT method is recommended for numerical modelling purposes. The porosity has a linear relationship with the flow velocity and a superlinear effect on the pressure drop. Accurate porosity data are essential to evaluate feed spacer performance in spiral-wound membrane systems. Porosity of spacer-filled feed channels has a strong impact on membrane performance and biofouling impact. Subject Feed spacer geometry modificationLinear flow velocityPorosity measurement methodsPressure dropSpacer-filled channel To reference this document use: http://resolver.tudelft.nl/uuid:f654c978-e3f3-4348-bdc8-b949e2e86d18 DOI https://doi.org/10.1016/j.watres.2017.04.034 ISSN 0043-1354 Source Water Research, 119, 304-311 Part of collection Institutional Repository Document type journal article Rights © 2017 A Siddiqui, S Lehmann, V.A. Haaksman, J. Ogier, Carsten Schellenberg, Mark C.M. van Loosdrecht, J. C. Kruithof, J.S. Vrouwenvelder Files PDF 1_s2.0_S004313541730297X_main.pdf 1.83 MB Close viewer /islandora/object/uuid:f654c978-e3f3-4348-bdc8-b949e2e86d18/datastream/OBJ/view