VISWA Technical Update: VLSFO Fuels with Contamination

by Viswa Lab
Tuesday December 10, 2019

As 1.1.2020 approaches, the supply of VLSFO fuels with 0.50% sulfur content has increased globally. These VLSFO fuels are coming from paraffinic and aromatic sources. The quality of these VLSFO's varies greatly with stability, catfines and cold flow properties being of significant concern. Unfortunately, we are also seeing a very high level of contaminants in some of these fuels.

Over the last few weeks, we have identified 6 fuels, 3 bunkered in Rotterdam, 2 in Antwerp and 1 in Singapore with high contamination levels. These fuels had upto a maximum of 4,900 ppm of Styrenes, 7,000 ppm of Indene's, 28,500 ppm of DCPD, 6,000 ppm of phenols and 2,800 ppm of 4‐Cumylphenol.

Presence of these contaminants at high levels has potential to cause purifier sludging, filter choking, fuel pump jamming and problems with fuel injectors. These contaminants are at the highest levels we have seen.

In 2014, the Port Authority of Rotterdam had prepared a list of six "undesirable substances" that should be banned from bunker fuels traded or supplied in the port. Please refer our earlier Technical Updates (TechUpd 2014_5_5 and TechUpd 2015_1_6).

These contaminants should not be present in bunker fuel. At these high levels they are likely to cause machinery problems. For this reason, they will not meet the criteria of Para 5 of ISO 8217.
It is better that you inform the supplier that you will be checking for these contaminants. You can also insist on the supplier providing you with a Certificate Of Quality (COQ) which should included a GCMS analysis.

It is disappointing that when the shipping industry is struggling to adjust to a new fuel, the old ghosts of contamination is adding to the problems.

To assist with questions related to 2020 fuels Viswa has started and in‐house 'Working Group'. You can reach us at

Please do not hesitate to contact us if you would like your VLSFO's tested.