Accidental release of ammonia during ammonia bunkering: Dispersion behaviour under the influence of operational and weather conditions in Singapore.

Ammonia is identified as a potential marine fuel, and ammonia bunkering will take place in major bunkering ports, including Singapore. Due to its toxic nature, any accidental release of ammonia into the environment during bunkering operation has a risk of spreading rapidly and causing injury to the personnel in the vicinity and damage to the marine ecosystem. This safety study simulates how key operational parameters affect ammonia dispersion and the consequences. The results show that bunkering ammonia stored in fully-refrigerated tanks as an atmospheric pressure saturated liquid is the safest, and the severity of the consequence increases significantly with a release height of more than 5 m. A vertical release of ammonia results in the most severe consequence and shall be avoided at all times. Reducing the release duration and transfer flow rate can reduce the severity significantly. Based on the scenario used in this study, ammonia cloud disperses over a longer distance over water due to the high vaporisation rate driven by the large amount of heat generated from the dissolution of ammonia in seawater. The dispersion of ammonia over the sea spreads over a larger area during the day than at night.