In the last decade, there is a growing interest in membrane distillation (MD) technology for treating hypersaline water and wastewater. However, MD commercialization is still limited by technical challenges such as temperature polarization, high energy required for heating the bulk feed solution, and heat losses. We demonstrate a proof-of-concept approach to overcome these limitations using stainless steel thermally conducting feed spacers. Feed spacers were directly heated by induction heating, a contactless and instant heating method, using radio frequency (RF) altering electromagnetic fields. Results show that heat was efficiently transferred to the water-membrane interface by conduction and advection, thus, eliminating the need to continuously heat the bulk feed solution. Furthermore, the RF heated spacers were shown (experimentally and by numerical simulations) to reduce temperature polarization. The influence of operating conditions (i.e., flow velocity, vacuum pressure, and power) and the spacer’s material and geometry were evaluated and results were compared to a conventional MD process using a polymeric spacer. Overall, results show that higher spacer mass and larger porosity led to an increase in distillate flux and that the use of thermally conducting spacers heated by RF significantly enhance the distillate flux while reducing the specific heating energy.

在过去的十年中，对用于处理高盐度水和废水的膜蒸馏（MD）技术的兴趣与日俱增。然而，MD的商业化仍然受到诸如温度极化，加热散装进料溶液所需的高能量以及热损失等技术挑战的限制。我们演示了使用不锈钢导热进料垫片克服这些限制的概念验证方法。通过感应加热（一种非接触式瞬时加热方法），使用改变电磁场的射频（RF），直接加热进料隔圈。结果表明，热量通过传导和对流有效地传递到水-膜界面，因此无需连续加热散装进料溶液。此外，显示了射频加热的垫片（通过实验和数值模拟），以减少温度极化。评估了操作条件（即流速，真空压力和功率）以及垫片的材料和几何形状的影响，并将结果与​​使用聚合物垫片的常规MD工艺进行了比较。总体而言，结果表明，较高的隔离物质量和较大的孔隙度会导致馏出物通量增加，并且使用由RF加热的导热隔离物会显着提高馏出物通量，同时降低比热能。功率和功率）以及垫片的材料和几何形状进行了评估，并将结果与​​使用聚合物垫片的常规MD工艺进行了比较。总体而言，结果表明，较高的隔离物质量和较大的孔隙度会导致馏出物通量增加，并且使用由RF加热的导热隔离物会显着提高馏出物通量，同时降低比热能。功率和功率）以及垫片的材料和几何形状进行了评估，并将结果与​​使用聚合物垫片的常规MD工艺进行了比较。总体而言，结果表明，较高的隔离物质量和较大的孔隙度会导致馏出物通量增加，并且使用由RF加热的导热隔离物会显着提高馏出物通量，同时降低比热能。