Multi-Effect Vacuum Membrane Distillation for High-Recovery Desalination

This study investigated the application of Multi-Effect Vacuum Membrane Distillation for treatment of brines with elevated salt content. The underlying objective was to extend the applicability of this hybrid thermal-membrane technology to water extraction from desalination brines and liquid desiccants. A set of tools and experimental methods was developed to support the design process of Vacuum Membrane Distillation systems. An experimentally validated system simulation model helped to predict the performance of multi-stage systems for a wide range of applications. It was combined with an in-depth analysis of heat and mass transfer phenomena in spacer-filled channels and an approach to predict inorganic membrane fouling. Experimental investigations of scale formation on the membranes helped to quantify the kinetics of crystal growth and the impact on the process. This included flux decline through membrane coverage with salt crystals and membrane wetting induced by crystals.