New opportunities in mass and energy consumption of the Multi-Stage Flash Distillation type of brackish water desalination process

The scope of this article is to provide solutions for two famous bottlenecks against more popularity of Multi-Stage Flash Distillation application among the world; supply required heat specially in remote areas and high rate of feed water rejection. To overcome the first challenge, adequate combinations of technologies for the available 197 ton/h MSFD unit in a case study plant and Direct Steam Generation (DSG) as an alternative renewable energy source are considered. The retrofit study on such plants may lead to achieve solar steam. Steam is used as heat source in the brine heater of Multi-Stage Flash Distillation unit. So, as the result of this modification, 17.8 MW of fossil energy is replaced by solar energy. In the second place, returning of more than 50 percent of the treated water to the river with around 14 °C temperature rise, by using cooling tower system, is prevented. It is revealed that for each of three existing thermal desalination plants up to 53 percent of feed water, i.e.; 667 m3/h and same amount of reject water can be conserved. Though, with this modification, the unit steam consumption has been increased up to 13 ton/h, about 50 percent of design value.