Membranes and modules for transmembrane distillation

Aqueous solutions can be concentrated and pure water prepared via a thermal membrane separation process. Membranes used for this purpose must be microporous and hydrophobic. A temperature difference causes a vapour transfer from the warmer to the colder side. Modules for this process are, for practical reasons, counterflow devices with capillary membranes that have good flow conditions outside a capillary bundle, too. This requires special capillary arrangements and module constructions.