Distillation of high concentrated salt solution by vacuum multi effect membrane distillation (VMEMD) of memsys

Abstract

Vacuum multi effect membrane distillation (VMEMD) is a thermal separation process with microporous hydrophobic membranes that is able to concentrate liquids with high salt concentrations close to saturation. This document describes the technology, test runs with high concentrated salt solution, observed phenomena and experiences gathered from the testing with VMEMD modules by memsys. Salt influences the distillation process in direction to lower distillate output due to boiling point elevation of the salt water. The process proofs reliability in a 365 days long-term testing with feed at conductivities between 130′000 μS/cm and 240′000 μS/cm (approximately 9.5–22wt% salt in solution) and distillate output with less than 10 μS/cm. The testing program delivers experience for the layout of modules with high recovery ratio.