FOBAS Alert: Estonian Shale Oil in VLSFO Fuels from ARA

by FOBAS
Tuesday December 17, 2019

Recently FOBAS has tested a number of VLSFO fuels from the ARA region with very high concentrations (up to 3%m/m) of Resorcinol's, phenols and other oxygenated compounds not usually found in marine fuels. The range of compounds detected is commonly associated with Estonian Shale oil and suggests this to have been used as a blend component in these fuels.

As many vessels are not yet using VLSFO fuels we have limited feedback on any attempted use of these fuels however the feedback from one ship which attempted to use the fuel after storing it in excess of a month encountered severe sludging at purifiers. Furthermore, there is historic evidence of fuels containing Estonian Shale oil causing problems due to sludging, particularly during purification and around filters.

While shale oils would not be considered contaminants and are considered acceptable blend components under ISO8217, they do appear to cause problems under certain conditions. In addition, the high concentrations of oxygenated compounds they contain can then mask other potential contaminants in the fuel when carrying out extended testing.

The fuels we have so far tested with Estonian Shale oil present have had high acid numbers, in the range from 0.98mgKOH/g to 1.85mgKOH/g.

We are continuing to investigate and gain feedback from vessels to gain an understanding of the behaviours of these fuels during use, however the concern is if many vessels are still waiting to put these fuels into use in late December then any potential problems may not become fully apparent until then.