Control of deposit formation during skim milk microfiltration (MF) remains challenging, particularly in membranes with spacer nets between membrane layers like flat-sheet and spiral-wound membranes, due to the extensive occurrence of flow shadows behind spacer filaments. One approach to improve process control and efficiency is applying pulsed or alternating flow, which creates regular fluctuations in shear stress, pressure and, for alternating flow, in flow direction. This study assessed the effects of these alternative flow types and compared them to conventional steady crossflow on deposit formation and filtration performance. Flux and protein permeation were monitored during filtration. After filtration, the membranes were removed and deposited proteins stained by Coomassie-blue. The visual analysis of the stained membranes confirmed that the alternative flow types improved access to flow shadows behind spacer filaments by causing a significantly reduced deposition or enhanced removal. Consequently, the reduced deposit formation with pulsed and alternating flow led to enhancements in the steady-state whey protein mass flow by >8% and >37% over any steady flow conditions. Considering the flow-specific pump energy demands, pulsed and alternating flow not only improved filtration performance, but also reduced specific energy consumption relative to whey protein mass transfer by >60%.

控制脱脂牛奶微滤 (MF) 过程中的沉积物形成仍然具有挑战性，特别是在膜层之间具有间隔网的膜中，例如平板膜和螺旋缠绕膜，因为间隔丝后面大量出现流影。改善过程控制和效率的一种方法是应用脉冲或交变流，这会在剪切应力、压力以及交变流的流动方向上产生规律的波动。本研究评估了这些替代流动类型的影响，并将它们与传统的稳定横流对沉积物形成和过滤性能进行了比较。在过滤过程中监测通量和蛋白质渗透。过滤后，去除膜并沉积考马斯蓝染色的蛋白质。对染色膜的视觉分析证实，替代流动类型通过显着减少沉积或增强去除来改善对间隔丝后面的流动阴影的访问。因此，在任何稳态流动条件下，脉冲和交替流减少的沉积物形成导致稳态乳清蛋白质量流量提高 >8% 和 >37%。考虑到特定流量泵的能量需求，脉冲流和交替流不仅提高了过滤性能，而且相对于乳清蛋白传质的特定能耗降低了 >60%。在任何稳态流动条件下，脉冲和交替流减少的沉积物形成导致稳态乳清蛋白质量流量提高 >8% 和 >37%。考虑到特定流量泵的能量需求，脉冲流和交替流不仅提高了过滤性能，而且相对于乳清蛋白传质的特定能耗降低了 >60%。在任何稳态流动条件下，脉冲和交替流减少的沉积物形成导致稳态乳清蛋白质量流量提高 >8% 和 >37%。考虑到特定流量泵的能量需求，脉冲流和交替流不仅提高了过滤性能，而且相对于乳清蛋白传质的特定能耗降低了 >60%。