Specific energy consumption analysis of reverse osmosis desalination system with energy recovery combination processes

Abstract

Energy recovery devices can reduce the specific energy consumption and operation cost of reverse osmosis desalination systems, which is an important core energy-saving equipment. In this paper, four combined processes were proposed, including turbine-free single-stage, single-turbine single-stage, dual-turbine two-stage, and single-turbine inter-stage pressurization for reverse osmosis seawater desalination systems, whilst ensuring the same influent flow rate and recovery rate. The whole process routes and equipment selection were also studied. To evaluate the performance of the combined process, the specific energy consumption ratios were analyzed with two different energy consumption ratio analysis methods. The results showed that energy recovery technology can reduce system-specific energy consumption. Optimizing the combination of turbine energy recovery devices, especially the combination process of dual-turbine double-stage desalination system and single-turbine inter-stage pressurized desalination system can significantly reduce the specific energy consumption and overall cost of the system.

Keywords

• desalination
• reverse osmosis
• specific energy consumption
• energy recovery device