Safety evaluation of using ammonia as marine fuel by analysing gas dispersion in a ship engine room using CFD

This paper seeks to address the question that each stakeholder in the maritime industry has about ammonia’s potential as a marine fuel, How safe is it to use ammonia as a fuel onboard vessel ? The principle aim of this paper is to quantify the exposure limits to which crew working onboard can get subjected to in a confined space onboard a vessel. It was achieved by simulating gas leaks at different locations inside an engine room of a hypothetical ammonia fuelled carrier similar to a 114,000 GWT LNG tanker using CFD. The transient nature of dispersion is analysed and compared for various scenarios. The results are promising and prove that ammonia does have a high risk due to its toxicity but a low risk in terms of flammability. Research findings also demonstrate that the gas dispersion depends on numerous factors such as position, area of leak, direction of leak, pressure and temperature of ammonia gas, obstruction due to placement of machinery and decks, ventilation, and the temperature gradient of surrounding material. The novelty of the paper lies in the problem it addresses and will contribute to the industry in a better understanding of the risk involved in operating an ammonia-fuelled vessel.