An industrial perspective on membrane distillation processes

Abstract

AbstractProcess intensification has led to significant developments in both distillation and membrane technology. Membrane distillation (MD) is an emerging technology for fluid separations that are typically performed by conventional separation processes, such as distillation or reverse osmosis (e.g. water desalination, or water removal). Compared with other membrane technologies, the driving force in MD is the difference in vapor pressure across the hydrophobic membrane, rather than the total pressure. MD can be a cost effective separation process, especially when more sustainable alternative sources of energy (e.g. geothermal and solar) or waste heat sources are used. Many review papers on MD are available in the open literature, but most of them focus on the membrane characteristics (e.g. material aspects).This industrial perspective paper assesses the MD technology and reports on relevant issues by offering a concise overview of MD technology, addressing different MD configurations, current major applications, operating parameters and their effect on the MD process, commercially available membranes, as well as cost estimations to determine the feasibility of MD processes. While successfully applied in desalination and a few other niche applications, MD has failed to make a strong industrial impact in other areas still dominated by distillation. A key message is that membrane distillation is still a growing technology for separation and purification processes, but it needs further exploration and optimization to become a mature technology applicable to more industrial processes in the chemical process industry. © 2018 Society of Chemical Industry