Impacts of non-uniform filament feed spacers characteristics on the hydraulic and anti-fouling performances in the spacer-filled membrane channels: Experiment and numerical simulation
Impacts of non-uniform filament feed spacers characteristics on the hydraulic and anti-fouling performances in the spacer-filled membrane channels: Experiment and numerical simulation
复制标题
非均匀长丝进料间隔件特性对间隔件填充膜通道水力和防污性能的影响：实验和数值模拟
DOI：
10.1016/j.watres.2020.116251
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发表时间：
2020
期刊：
影响因子：
12.8
通讯作者：
Xia Huang
中科院分区：
文献类型：
--
作者：
Wei-chen Lin;Rui-peng Shao;Xiao-mao Wang;Xia Huang
进料隔片在螺旋缠绕式纳滤（NF）和反渗透（RO）膜组件中普遍使用。它可以分离膜片，创建流动通道，促进湍流和增强传质。然而，它也引起跨流动通道的压降增加，并在特定位置处产生生物膜生长的死区。进料间隔件几何形状的优化对于节能和生物污染控制是非常期望的。本研究比较了四种商品化的非均匀纤维型隔水管的水力性能和抗污性能。启动计算流体动力学（CFD）模拟，以深入了解进料间隔器特性对流场的影响。结果表明，纤维层数（单层或双层）、纤维直径的不均匀性和减薄区的宽度对水力性能有显著影响。不均匀长丝的单层进料隔片由于流阻大、抗结垢性能差而不推荐设计。交替丝径的进料隔片结构有助于减少死区，减轻膜污染。位于长丝连接处附近的变薄区实现了更好的防污性能，因为它扰乱了死区并部分冲走了沉积的污垢。该研究首次揭示了非均匀喂丝隔圈的特性对水力性能和抗污性能的重要影响，并提出今后喂丝隔圈的优化应重点关注喂丝层数、喂丝直径和宽度的变化以及喂丝隔圈的细化区位置。
Feed spacer is universally used in spiral-wound nanofiltration (NF) and reverse osmosis (RO) membrane modules. It can separate membrane sheets, create flow channels, promote turbulence and enhance mass transfer. However, it also induces increased pressure drop across the flow channel, and generates dead zones for biofilm growth at specific locations. Optimization of feed spacer geometries is highly desirable for energy saving and biofouling control. In this study, four kinds of commercial feed spacers featured with non-uniform filaments were compared in terms of hydraulic and anti-fouling performances. Computational fluid dynamics (CFD) simulations were launched to give insights into the impacts of feed spacer characteristics on the flow field. Results show that the hydraulic performance was substantially affected by the number of filament layers (single or dual layer), the non-uniformity of filament diameter and the width of thinning zones. The design of single layer feed spacer of non-uniform filaments was not recommended due to high flow resistance and poor anti-fouling performance. The feed spacer structure of alternating filament diameter contributed to reducing dead zones and alleviating membrane fouling. The thinning zones located adjacent to the filament junctions achieved better anti-fouling performance, as it disturbed the dead zones and partially washed away the deposited foulants. This study demonstrates for the first time that the characteristics of non-uniform filament feed spacer had a crucial impact on the hydraulic and anti-fouling performances, and suggests that more emphasis should be laid on number of filament layers, variation of filament diameter and width and positioning of thinning zones for the optimization of feed spacer geometries in the future.