Hazardous consequence dynamic simulation of LNG spill on water for ship-to-ship bunkering

The significant hazards associated with LNG ship-to-ship bunkering could involve LNG vapour dispersion and LNG pool fires. The boil-off LNG vapour initially behaves as a denser-than-air vapour due to its cryogenic temperature and then is dissipated, as the vapour cloud heated up by surrounding environment. LNG pool fires occur due to either the source ignites immediately or a flash fire burns back to the source. It could cause thermal radiation damage to the surrounding properties or people. Due to different LNG discharge locations, i.e. below waterline, at waterline and above waterline, three possibilities of lumped LNG vapour source planes were compared to investigate the vapour dispersion behaviours and fire radiation hazards in different cases. The present study is aimed at capturing the features of different hazards, analysing the potential hazardous area and investigating a possible mitigation method by applying computational fluid dynamics. Thermal radiant heat flux and temperature were utilised to analyse the material effectiveness on both the LNG bunker and the cargo vessel. The water curtain, which is commonly used to prevent material stress cracking in case of LNG leakage, were considered appropriately to mitigate the radiation hazard.