Study on the Optimum Design of the IMO Type C LNG Fuel Tank Considering Characteristics of Cryogenic Materials

摘要

As a solution to the emission controls, there is an increasing interest in the use of LNG as ship fuel. Accordingly various types and materials are suggested for the containment system of LNG. In this study, the various cryogenic materials for the IMO Type C LNG fuel tank are reviewed to be installed on world’s first LNG-fuelled AFRAMAX tanker. The design results and relevant costs are compared for the LNG fuel tanks made of various cryogenic materials such as 9% nickel alloy steel, stainless steel, aluminum and high manganese steel. The LNG fuel tanks of each material have been designed reflecting the material characteristics adopted by Classification Societies. In order to verify the structural integrity, the LNG fuel tank structures have been evaluated through structural strength assessment. Finally, after the cost comparison using the weight of base metal, the weight of relevant weldment and the required manpower considering weldability of each material, 9% nickel alloy steel has been selected as the optimum material for the LNG fuel tank.