Evaluating Thermal Resistance in Cryogenic LNG Cargo Containment Systems: A Case Study of The Tangguh–FSRU Jawa Satu Transport Route

Abstract

This study evaluated the thermal resistance performance of spherical cryogenic storage tanks on liquefied natural gas carriers operating between the Tangguh refinery and the Jawa Satu Floating Storage Regasification Unit to address the operational challenge of cargo shrinkage. The natural evaporation of cryogenic fluids during maritime transportation represented a physical loss of energy supply and caused a significant financial burden on the national energy supply chain. To measure the thermal efficiency of the tanks, the theoretical heat transfer rate and the theoretical daily boil-off rate were calculated based on the thermal resistance of the composite wall structure. These theoretical baselines were then compared with actual volume shrinkage data from voyage reports to determine the efficiency deviation and the subsequent economic loss. The analytical model demonstrated that the theoretical heat transfer rate penetrating the storage system was 116.9 kW, which corresponded to an expected daily boil-off rate of 0.17%/day. However, the field performance data revealed an actual daily boil-off rate of 0.35%/day. This comparison identified a performance inefficiency deviation of 0.18%/day, which was attributed to the degradation of the insulation materials. Consequently, this thermal inefficiency caused a commercial energy supply failure of 31,351.46 MMBtu that evaporated during the voyage. This energy loss translated to a financial deficit of $194,108.77 for a single voyage cycle, highlighting the critical necessity for strict insulation maintenance.