ExxonMobil has issued best practice tips for switching to low sulphur fuel ahead of the International Maritime Organization’s (IMO) 0.5 per cent sulphur cap which comes into force in 2020.

“With so many different types of fuel potentially set to enter the bunker market, vessel operators are rightly concerned about stability, compatibility and quality issues, such as elevated levels of cat fines,” said John LaRese, Marine Fuels Technical Advisor, ExxonMobil. “It will therefore be more important than ever for operators to follow best practice when bunkering compliant fuels, including using laboratories to test fuel samples for potential issues.”

The oil conglomerate issued a statement that outlined established best practices.

Prevention is always better than cure, the company said, so it is advisable to buy fuel that meets the latest ISO 8217:2017 specifications; only bunker from reputable fuel suppliers and clean out bunker tank residues when necessary.

Some new 0.5 per cent sulphur fuels could contain elevated levels of cat fines which, if not properly treated, could trigger catastrophic engine damage, ExxonMobil noted.

If laboratory testing shows a high concentration, then operators should maintain storage tank temperatures at least 10°C above fuel pour point, keep settling tanks at 85°C, operate purifiers at optimum efficiency and minimum throughput and drain water from fuel tanks to aid settling.

There is a risk also that two compliant fuels will not be compatible, which can trigger sludge formation.