WATER DESALINATION BY PERVAPORATION WITH HOLLOW-FIBER MEMBRANES

A new desalination process consisting of air humidification by pervapo ration through hydrophilic or microporous hydrophobic hollow fibers fo llowed by dehumidification by cooling water was investigated. In this system hot water is passed through hollow fibers in a recycled air-swe ep pervaporation process. The water is heated by waste heat or solar e nergy or by any other cheap source of energy. The flux of water throug h the hollow fibers is in the range of 1.5-3.0 l/m(2)h, when water tem perature is 45-65 degrees C. The energy requirement for recycling hot water depends on water temperature as well as on the diameter and leng th of the hollow fibers. The energy requirement for air recycling depe nds on the air temperature and on the pressure drop of the system. The calculated energy requirement for pumping air and water in a pilot pl ant unit of a capacity of 6.3 l/h with 4 m(2) of anion-exchange hollow fibers was about 2 kWh/m(3), when hot water temperature was 60 degree s C.