Assessment of energy saving effects in membrane-based seawater desalination

摘要

In reverse osmosis (RO) process for seawater desalination, the most important issue is the energy consumption. Intensive efforts have been contributed to freshwater production from seawater at low energy so far. This work analyzes the amount of energy consumption for various energy saving methods proposed by literatures using five commercial RO simulation programs (e.g., CSMPRO Ver 5.0, IMS-Design - 2016, ROSA 9.0, LG Chem NanoH(2)O, and Toray DS2). The RO energy consumption can be saved by: (1) adopting high flux RO membranes (0.23-0.67 kWh/m(3)), (2) increasing feed water temperature (0.01-0.03 kWh/m(3)/degrees C), (3) increasing RO train size (1.17-1.35 kWh/m(3) for sizing up from 1,000 to 10,000 m(3)/d), (4) increasing RO membrane area (0.01-0.02 kWh/m(3)/% increase), and (5) decreasing feed concentration (0.02 kWh/m(3)/% decrease). If fouling occurs, the RO energy consumption increases by 0.05 kWh/m(3)/bar. Comparing the positive effect of energy saving methods and the negative effect of fouling, one can set an optimal strategy for energy saving in RO-based seawater desalination according to a specific situation.