Introduction to desalination plants

Desalination plants are industrial facilities designed to remove salt and other minerals from saline or brackish water, converting it into water suitable for human consumption, irrigation or industrial use. Its main function is to provide an alternative source of fresh water in regions where conventional water resources are insufficient or contaminated.

This type of plants has gained special relevance in arid and semi-arid areas, as well as in coastal areas, where seawater is abundant but not drinkable. Desalination technologies have evolved to optimize energy consumption and reduce environmental impact, making desalination plants a strategic solution to global water scarcity.

Thermal processes

Thermal desalination processes are based on the evaporation and subsequent condensation of water to separate salt and other dissolved solids. Among the most common thermal technologies are multi-effect distillation (MED) and vapor compression distillation (VC).

Multi-effect distillation uses multiple stages where the steam generated in one stage serves to heat the next, increasing thermal efficiency. For its part, vapor compression recycles the vapor produced, reducing energy consumption. These technologies are usually more efficient in large-scale plants and when waste or cheap heat sources are available.

However, thermal processes typically have higher overall energy consumption compared to some membrane technologies, which can present a challenge in terms of operating costs and associated emissions.

membrane processes

Membrane technologies, especially reverse osmosis (RO), have established themselves as the most used worldwide for desalination. The basic principle consists of forcing the passage of water through a semipermeable membrane that retains salts and contaminants, allowing fresh water to be obtained.

Reverse osmosis requires high pressures to overcome the natural osmotic pressure of saline water, so energy consumption is mainly concentrated in pumping. However, technological advances have made it possible to significantly reduce this consumption through high-efficiency pumps and energy recovery systems.