Energy savings in single-purpose desalination systems

In this paper, an energy efficient combination is suggested for single-purpose desalination systems. The present analysis is based on data for existing units known for their reliabilities and high performances. For a specific steam power cycle, the generated power drives a RO, RO/MSF or RO/MEB system. In these combinations, the pretreated hp brine discarded by the RO is introduced as the feed for the distillation unit. Thus, the feed treatment, as well as the feed pumping required, is saved. The TBT and the bottom temperature in the distillation unit are set at 112 and 47°C, respectively. Results show that, using the same steam power cycle, a water production of 4, 4·26 or 6·2 MGD can be produced if it drives a RO, RO/MSF or RO/MEB system, respectively. Moreover, the energy consumed per unit of fresh water produced (in kJ/kg) is 281, 265 or 182 for the RO, RO/MSF or RO/MEB system, respectively.