Material Selection for the Gas Containment System of a Compressed Natural Gas Carrier Fleet

tIn this work, the possible exploitation of fiber-reinforced composites in the context of maritime trans-portation of compressed natural gas (CNG) is investigated. In addition to a more conventional steelconfiguration, two different fiber materials, carbon and glass, are considered as construction materialsfor pressure vessels (PVs) to be stored on board ships, with thickness optimized by FEM analysis.The considered scenario is represented by the transportation of CNG from an offshore well to a terminalon shore. Fleets of ships carrying CNG in pressure vessels manufactured with the investigated materialsare generated by means of a ship synthesis model (SSM) software and compared on the basis of technicaland economical indicators.The choice of the construction material influences considerably the weight of the PVs, which representa major item of total ship weight and reflects directly on the general transport performances in termsof resistance, seakeeping and reliability in the service. On the other hand, capital as well as operatingexpenditures are considerably affected by the choice. When exploring the design space, the ship synthesismodel is able, at a preliminary stage of the design, to account for the various technical and economicalaspects, their implications and relationships. Results are presented of computations carried out in aspecific case, identified by the annual gas production and other characteristics of the well terminal anda cruising route for the ships. The comparison is carried out on the basis of the cost per transported unitof gas and of the percentage of success in the transportation process. The computations show that thechoice of the PV material has a key influence on the results in terms of optimal number, dimensions andspeed of the ships.