A comparison of the toxicity and asphyxiation risk during bunkering of LH2, LNG and NH3 by means of a quantitative risk assessment

Abstract

To achieve the greenhouse gas (GHG) reduction goals set by the International Maritime Organization (IMO), hydrogen, natural gas and ammonia are considered as marine fuel in their liquefied form. Nevertheless, concerns regarding their safety have been raised. Thus, the overarching aim of this investigation is it to addresses these concerns by conducting a comparative analysis of the safety of bunkering these fuels, with a particular focus on toxicity and asphyxiation hazards. A quantitative risk assessment is thus conducted in two steps: first, to identify the probability through a frequency analysis and second, to identify the severity through a consequence analysis. The present study will utilize the requisite safety distance as the threshold for the severity. The calculation of the safety distance necessary for the different fuels is performed utilizing a Gaussian dispersion model. Subsequently, both the necessary safety distance and the frequency of harmful events of all three fuels are then compared. The findings indicate that the frequencies of the toxicity/asphyxiation case are of comparable order magnitude for all fuels. However, the safety distance of ammonia is one order of magnitude larger than that of the other fuels.