Energy Efficient Fresh Water Maker

Design Criteria

A number of new 167,000 GT energy efficient cruise ships were being constructed for a premium cruise brand. Each ship was to be fitted with three RO plants, each capable of producing 800m³/d of desalinated fresh water from seawater. The RO plants will supply fresh water to the 6,000 plus persons on board.

Design Solution

The RO plants were skid mounted and, due to the size of the plant, installed during the construction of the ship (the ship was effectively built around the plants). The design solution includes lifting beams and points to facilitate removal of larger equipment for maintenance purposes and the plant also included walkways and access ladders for sand filter filling.

Each plant comprises of automated suction/discharge valves, feed/backwash pump, two sand filters in parallel, antiscalant dosing, cartridge filtration, high pressure pumps, RO stack and automatic permeate dump system. The electrical control panel provides operator interface, annunciates all alarm conditions/safety trips and controls the automatic backwash operation of the sand filters as well as the automatic operation of the plant.

The innovative solution includes two-pass RO technology to produce RO permeate to a very high quality as well as isobaric energy recovery technology, dramatically reducing the power requirements of the RO plants to less than 3.5 kW/m³.