ABSTRACT#164
The International Maritime Organization (IMO) implemented a new regulation in 2020 that limited the sulfur content of fuel oil used on board ships to 0.5% (from 3.5% previously) in an effort to reduce sulfur oxide (SOx) emissions. The IMO estimates that this regulation, known as “IMO 2020,” will result in a 77% decrease in total SOx emissions from ships annually. This has led to an increase in the use and transport of Low Sulphur Fuel Oil (LSFO) with commensurate increasing risk of spills. The objective of this study was to examine the physico-chemical properties and dispersibility of LSFOs in comparison to conventional crude oils (CCOs). Three LSFOs (Wide Range Gas Oil, Marine Gas Oil and Bunker Fuel Oil) and three CCOs (Alaskan North Slope, Endicott and Dorado Crude Oil) were tested. The density, percentage of sulphur, alkanes (n-C10 to n-C35), and polycyclic aromatic hydrocarbons for these oils were evaluated to better understand their physical and chemical properties. Dispersion Effectiveness (DE) using the standard baffled flask test, oil droplet size distribution using the Laser In Situ Scattering and Transmissometry probe (LISST-100X, Sequoia Scientific, Inc.) and the interfacial tension between the oil droplet and the artificial seawater were evaluated to determine each oil's ability to disperse at a lab scale. Results indicate that the physico-chemical properties of the three LSFOs vary significantly amongst each other and from conventional crudes. The DE decreased with increasing density irrespective of fuel class. A higher proportion of larger oil droplets were observed in samples with lower DE for the denser oils. These findings suggest that the class of marine fuels collectively termed LSFOs can show a significant range in density, composition and dispersibility and the various types of LSFOs that are currently in use require further investigation to fully assess their properties, behavior, and impacts in the event of a spill.