Thermal separation process by membrane distillation modules

Membrane distillation (MD) is a separation process based on the vapor transport across the hydrophobic microporous membrane driven by the vapor pressure gradient across the membrane. Membrane distillation (MD) is an emerging technology for separations that are traditionally accomplished by conventional separation processes such as distillation or reverse osmosis. Since its appearance in the late of the 1960s and its development in the early of 1980s with the growth of membrane engineering, MD claims to be a cost effective separation process that can utilize low-grade waste and/or alternative energy sources such as solar and geothermal energy. However, this technology, though the first patent dates from 1963, its use is currently beginning to emerge harnessing all the developments in membrane engineering. It is membrane distillation. Some useful technical discussions based on acquired knowledge from experience and information gathered from MD literature are included. This paper summarises a model of the modular Membrane Distillation (VADEST MD) process. Membrane distillation (MD) has gained significant regard from industrial and academic perspective in recent years, thus the frequency of publications related to the field has greatly accelerated. New perspectives have boosted the research activities related to deeper understanding of heat and mass transport phenomenon, novel applications and fabrication of the membranes specifically designed for MD. The treatment of saline and briny effluents is not possible using conventional processes. The only technology that offers a complete solution is vacuum evaporation, given that reverse osmosis or electrodialysis generate a discharge effluent that must be managed. And conventional distillation entails costs that make it financially unviable.

Keywords:

hydrophobic microporous membrane , Modular Membrane distillation , reverse osmosis