FOBAS says is it is continuing to see more cases of contaminated bunker fuel in the ARA region – mainly in Rotterdam and Amsterdam – which suggests that the problem is an ongoing one.
As previously reported, in June FOBAS said it had investigated a number of very low sulphur fuel oil (VLSFO) samples taken in the ARA region after reports that vessels using these fuels had experienced operational problems such as excessive wear of fuel pump plungers, barrels and fuel injectors.
FOBAS noted that some vessels had to discontinue using the VLSFOs and its analysis has shown that the fuels exhibited a Total Acid Number (TAN) ranging from 1.33 to 2.59 mg KOH/g and all contained ‘unusually high’ levels of Potassium.
In a new bulletin issued this week, FOBAS said it had also seen a similar contamination case from Ulsan, Korea and a recent case with lower levels of the same contaminants from Singapore.
Detailed analysis on these fuels has shown a range of compounds, more specifically, high levels of phenolic compounds. The compounds with highest concentrations are Cardanol (also referred to as Ginkgol and other chemical names) and Cardol which are not normally seen in marine fuels.
According to FOBAS, the concentration of these extraneous components ranged from 20, 000 to in excess of 140,000 ppm.
The fuel testing agency noted that phenol related compounds are often linked with fuel pump wear and damage.
‘In the case of the recent fuels tested where Cardanol alone was at >100,000ppm concentration (>10% total fuel), we would expect this to affect the fuel behaviour considerably,’ it said.
‘These fuels were also found to have been blended with Estonian shale oils. Although use of shale oil as a blend component is allowed under ISO 8217 specifications, Estonian shale oils have a tendency to fall apart during purification, which leads to sludging issues during purification.’
It continued: ‘Further investigation continues in order to identify the exact source and intention of these chemicals. However, regardless of the source or intention for these chemicals in the fuel, the concern is that some of the vessels using these fuels are reporting operational problems, particularly involving fuel pump wear and damage.’