Desalination energy minimization using thin film nanocomposite membranes

Abstract

In this study, thin film nanocomposite (TFN) reverse osmosis (RO) membranes were evaluated at a demonstration-scale facility to determine the specific energy consumption (SEC) during seawater desalination. Conventional (same element type within pressure vessel) and hybrid (high and low rejection elements within pressure vessel) configurations were evaluated and compared to commercially available thin film composite (TFC) RO membranes. The specific flux at 25°C for TFN RO membranes was 1.72lm-2h-1/bar when compared to 1.48lm-2h-1/bar for TFC RO membranes. Utilization of TFN RO membranes resulted in reduced feed pressure requirements when compared to TFC RO membranes, resulting in energy savings up to 10%. In order to achieve the same permeate water quality, the SEC for a 2-pass RO system with TFN RO membrane elements in the first pass was 3.24-3.45kWh/m3. The SEC with TFC RO membrane elements for the same conditions was 3.60kWh/m3. Results presented in this study show a promise for the utilization of TFN RO membranes to reduce energy consumption and minimize operational costs associated with electricity usage. © 2014 Elsevier B.V.