Water in ships and marine installations is essential to guarantee their autonomy and operation, as well as the quality of life of their crews. However, transporting it is a problem as it requires a large amount of space that is not available on ships. This is why these installations resort to water treatment solutions to generate water on board, in most cases to obtain sanitary or drinking water for consumption.
The continuous production of fresh water on vessels is achieved through efficient desalination systems such as reverse osmosis. A process that, in addition to obtaining pure water from seawater, not only saves space on the boat but also weight, which considerably reduces its energy and fuel costs.
With reverse osmosis, water taken directly from the sea is pressurised through semi-permeable membranes. These membranes only allow certain water molecules to pass through, leaving behind other components and the salt itself. And after this passage, two flows are generated: one of fresh water and the other of rejection.
This is how it is possible to generate unlimited fresh water on board a ship. This transformation process runs continuously and can generate salt-free water for entire journeys.
Reverse osmosis systems for the offshore patrol vessels “Serviola”
The offshore patrol vessels “Serviola” are a series of four ships belonging to the Spanish Navy and are responsible for regular surveillance operations in maritime areas of national interest. In addition, they participate annually in scheduled exercises with other State units and agencies with responsibilities in the maritime sphere.
These vessels currently have four evaporators, one per ship. Such evaporators, now obsolete, hinder the capacity to produce technical water, causing the vessels to become inoperative.
In this context, SETAᴾᴴᵀ is working on the replacement of the evaporators with four reverse osmosis water production units, one per vessel. The purpose of each unit is to treat seawater, with a guaranteed production of a minimum flow of 7,000 litres/day of desalinated water.
This project has been a challenge for the SETAᴾᴴᵀ technical office. The reverse osmosis equipment has been designed under specific conditions to be located in a minimum of space, with the added difficulty of introducing all the components for desalination through a hatch of very small dimensions.
This success comes from the combination of vast engineering experience and the use of high quality components. The first unit has already been installed on the vessel Centinela. The next three units will be installed successively depending on the availability of the vessels.