In the maritime industry, most perceptions, frameworks and methodologies of dealing with hazards are for their risk assessment rather than their risk management. This tendency discloses the reality that within the maritime sectors in areas like shipping, logistics, oil and gas there is a lack of coherent Quantitative Risk Management (QRM) methodology from which to understand the risk-based decisions especially for appropriate risk management such as in seaports’ terminals. Therefore, in this paper initially, during priority assessment of the identified hazards, Fuzzy Set Theory was applied to handle imprecision of the uncertain risk-based statistics to get an accurate result. In the next stage, Fuzzy Fault Tree and Fuzzy Event Tree methods were used to achieve the sequence of quantitative risk analysis. In the final step, a Fuzzy Technique for Order of Preference by Similarity to Ideal Solution tool was used for the implementation of the mitigation phase to complete and conclude the proposed QRM cycle.

As a fuel for ship propulsion, liquefied natural gas (LNG) is currently considered a proven and reasonable solution for meeting the IMO emission regulations, with gas engines for the LNG-fueled ship covering a broad range of power outputs. For an LNG-fueled ship, the LNG bunkering process is different from the HFO bunkering process, in the sense that the cryogenic liquid transfer generates a considerable amount of boil-off gas (BOG). This study investigated the effect of the temperature difference on boil-off gas (BOG) production during ship-to-ship (STS) LNG bunkering to the receiving tank of the LNG-fueled ship. A concept design was resumed for the cargo/fuel tanks in the LNG bunkering vessel and the receiving vessel, as well as for LNG handling systems. Subsequently, the storage tank capacities of the LNG were 4,500 m3 for the bunkering vessel and 700 m3 for the receiving vessel. Process dynamic simulations by Aspen HYSYS were performed under several bunkering scenarios, which demonstrated that the boil-off gas and resulting pressure buildup in the receiving vessel were mainly determined by the temperature difference between bunkering and the receiving tank, pressure of the receiving tank, and amount of remaining LNG.