ABSTRACT
Thermal desalination processes involve the evaporation and condensation of water. The main thermal desalination technologies are divided into three groups: multi-effect distillation (MED), multi-stage flash (MSF), and vapor compression. The MED process is more thermodynamically efficient than the MSF with low-temperature multi-effect distillation, LT-MED being the most efficient of all thermal distillation processes. Water vapor may also be compressed by an ejector system motivated by high-pressure steam. This form is called thermal vapor compression. In the once through MSF system the whole amount of treated seawater flows through the condenser tube in heat rejection, heat recovery to the brine heater, and into the flash chamber. In other thermal processes, submerged tubes of heating steam are usually used to perform evaporation. Other thermal desalination processes including freezing, solar stills and humidification–dehumidification are only found on pilot or experimental scale. They can also be utilized alongside other desalination processes.
