Membrane Distillation Case Study

1) MEMBRANE DISTILLATION

Membrane distillation (MD) is one of the membrane-based separation processes. The driving force for MD processes is the vapor pressure difference across the membrane which is created by applying temperature on feed side. Though the development of membrane distillation has been started since 1960s and many reported studies have been published, MD has gained little acceptance in industry or practice and is yet to be implemented in large scale. Its limitations over other membrane based processes like Reverse Osmosis (RO) makes MD less preferable. This report mainly concentrates the principle of MD, its limitations over other processes and, how to implement MD industrially and what are the factors that hinder MD applications and in what ways we can solve those obstructions. 1.1 Motivation to improve efficiency of MD: According

But not all applications have economic feasibility to be practically/industrially implemented. MD can be used as either single process or coupled with other technologies. One of the attractive applications for MD is for treating high saline water (brine) such as concentrate of Reverse Osmosis (RO). This is applied in the case where, RO membrane becomes more expensive, due to very high osmotic pressure, and is problematic due to scaling phenomenon. MD, which is not limited by the concentration of solute and has ability to work with near saturated solution, is interesting to be used in this application. In relation with this application, MD has been integrated to the crystallizer to produce supersaturation solution as well as pure water .In this way, two product streams can be obtained, pure water from permeate and solid crystal from