CONICET | Buscador de Institutos y Recursos Humanos

Distillation and reverse osmosis are the two most common processes to obtain fresh water from seawater or brackish water. A leading distillation method is the Multi Stage Flash process (MSF). For this method, fresh water is obtained by applying thermal energy to seawater feed in multiple stages creating a distillate stream for fresh water uses, and a concentrated (brine) stream that is returned to the sea. In Reverse Osmosis processes (RO), the seawater feed is pumped at high pressure to special membranes, forcing fresh water to flow through the membranes. The concentrate (brine) remains on the upstream side of the membranes, and generally, this stream is passed through a mechanical energy recovery device before being discharged back to the sea. Desalination plants require significant amounts of energy as heat or electricity form and significant amounts of equipments. Reverse osmosis plants typically require less energy than thermal distillation plants. However, the membrane replacement and the high-pressure pumps increase the RO production cost significantly. Furthermore, even the salt concentration of permeated stream is low; this stream is not free of salt, as the distillate stream produced by a MSF system. Therefore, hybrid system combining thermal and membrane processes are being studied as promising options. Hybrid plants have potential advantages of a low power demand and improved water quality; meanwhile the recovery factor can be improved resulting in a lower operative cost as compared to stand alone RO or MSF plants. Several models have already been described in the literature to find an efficient relationship between both desalination processes (Helal et al., 2003; Agashichev, 2004; Cardona & Piacentino, 2004; Marcovecchio et al., 2005). However, these works analyse only specific fixed configurations for the RO-MSF hybridization.