Which desalination method is used by most ships?

Which desalination method is used by most ships?

• A. Reverse osmosis desalination
• B. Flash type distiller
• C. Multi-effect distillation
• D. Electrodialysis

Answer: (A)

The main idea is why shipboard desalination favors a method that fits the constraints of a vessel—space, weight, fuel, and reliability. Reverse osmosis is the common choice because it uses membranes and a high-pressure pump to push seawater through, leaving salts behind. Modern RO systems on ships include energy-recovery devices that reclaim energy from the high-pressure brine, making the process much more energy-efficient. This combination yields a compact, modular, and reliable plant suitable for continuous operation in rough seas and with variable water quality. In contrast, thermal methods like flash distillation or multi-effect distillation require large amounts of heat and bigger footprints, which means more fuel use and space—disadvantages on a ship. Electrodialysis can desalinate water, but its efficiency drops at seawater salinity, and it’s generally more suited to brackish water than large-scale shipboard potable water. For these reasons, reverse osmosis is the method most ships use.

The main idea is why shipboard desalination favors a method that fits the constraints of a vessel—space, weight, fuel, and reliability. Reverse osmosis is the common choice because it uses membranes and a high-pressure pump to push seawater through, leaving salts behind. Modern RO systems on ships include energy-recovery devices that reclaim energy from the high-pressure brine, making the process much more energy-efficient. This combination yields a compact, modular, and reliable plant suitable for continuous operation in rough seas and with variable water quality.

In contrast, thermal methods like flash distillation or multi-effect distillation require large amounts of heat and bigger footprints, which means more fuel use and space—disadvantages on a ship. Electrodialysis can desalinate water, but its efficiency drops at seawater salinity, and it’s generally more suited to brackish water than large-scale shipboard potable water. For these reasons, reverse osmosis is the method most ships use.