ABSTRACT
Liquefied Natural Gas is stored at Cryogenic temperatures within tanks of Floating Storage Regasification Units. The tanks are provided with containment systems to store the LNG below the boiling point. The structural steel of the FSRU hull i.e. the external boundaries of the tank walls could be subject to very low temperatures. It is essential to select the appropriate grade of steel so as to prevent embrittlement of the tank walls. Hence it is imperative to perform a thermal analysis to determine the temperatures at various locations in the tank walls. The tank bulkheads are also provided with heating arrangements because of the low temperatures they are subjected to, since it may become impractical to provided protection merely by selection of steel grade. The present paper demonstrates the calculation of the temperatures and evaluation of the steel grades in a FSRU tank (membrane type containment system). Further it also demonstrates the calculation of required heating capacity of the coils installed within the cofferdams. The paper also brings out the important factors to be considered during the calculations.
