Speaker
Description
As decarbonization has become an important issue, traditional marine fuel is being replaced with cryogenic liquids, such as LNG, LPG, and LH2. Cryogenic liquids inevitably generate boil-off gas (BOG) due to the heat caused by a significant temperature difference from the atmosphere, which increases the internal pressure. Hence, BOG handling equipment is required to manage the BOG and maintain the design pressure during operation, and it is important to expect the pressure increase precisely to design the equipment.
Various types of tanks are used for storing cryogenic liquids, such as membrane-type tanks for LNG carriers, and Type-C and Type-B tanks for LNG/LPG fuel tanks. In the case of LH2 carriers, which are currently under development, research is underway to use Type-C and membrane tanks. Each tank has a different shape and internal support, which affects the flow inside the tank during the voyage.
The flow inside the tank is known to impact not only the pressure on the tank walls but also the evaporation of the cryogenic fluid. Therefore, to accurately predict the pressure change during tank operation, it is necessary to consider the effects of the internal supports, which vary according to the tank type.
This study analyses pressure changes by predicting phase changes in tanks while considering the effects of the internal support for the safety design of tanks. Specifically, the characteristics of pressure changes in tanks were predicted during laden and ballast voyages while transporting cryogenic fluids, considering the change of operating conditions due to the environment.
References
DNV, “Maritime forecast to 2050”, Energy transition outlook 2022, 2022
LUDWIG, Carina; DREYER, M. E.; HOPFINGER, E. J. Pressure variations in a cryogenic liquid storage tank subjected to periodic excitations. International Journal of Heat and Mass Transfer, 2013, 66: 223-234.
| Keywords | Cryogenic tank, Safety, BOG, CFD, Phase change |
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