Brackish water: Energy, costs and the use of energy recovery devices

New devices can now provide greater energy savings and improved operational flexibility in brackish water desalination. The ERI™ Turbocharge™ device, transfers pressure energy from one liquid stream to a second liquid stream. It consists of a pump impeller section and a turbine rotor section. The turbine rotor depressurizes the brine while extracting the energy in the form of high speed rotational torque. ERDs are specifically used to offer power savings to the end user. The efficiencies gained are the result of an intensive program using meanline codes and CFD codes to optimize the design and manufacturing technology using 5-axis CNC machining. In addition to saving energy, the turbocharger acts to balance flux between the stages. The closer match between the interstage and second stage concentrate flows, as compared to that of the first stage feed and concentrate, which means that the turbine and impeller will operate at a higher overall efficiency.