Experimental Study for Pressure Exchanger Applied to Brackish Water

Abstract

Over the last ten years, reverse osmosis (RO) desalination technique became the most common and popular technology to desalinate brackish and seawater due to its low cost and simplicity. Great efforts have been conducted to reduce the energy consumption in reverse osmosis plants. One of the most efficient techniques is the pressure exchanger (PX) which utilizes the high pressure existing in waste concentrate to pressurize a part of feed brackish or seawater. The present research deals only with a pressure exchanger for brackish water. Such PX was manufactured specifically for the present work from simple materials such as cast iron and plastics to match brackish water technical and financial conditions. Results showed that PX for brackish water has a lower hydraulic efficiency than PX for seawater application. The present ultimate hydraulic efficiency is 25.6% compared to 95% for seawater PX manufactured by ERI (the single manufacturer in the Globe) with a higher mixing rate.