As the fifth anniversary of the IMO 2020 Sulphur Cap approaches, fuel compatibility and viscosity problems continue to result in marine engine component damage and high cat fines.

“We expected fuel incompatibility problems and high levels of cat fines to diminish with the introduction of the IMO 2020 Sulphur Cap [MARPOL Annex VI] in January 2020. But despite new fuels and advanced engine technologies, problems persist. Cat fines remain a major problem for marine engine operators,” said Matthias Winkler, Managing Director of CM Technologies (CMT).

Catalytic fines are the byproduct of catalysts used in the fuel refining process. It is the accumulation of these very hard, abrasive aluminium and silicon particles that can severely damage cylinder liners, fuel injection valves, piston crowns and rings, potentially damaging the engine beyond repair.

Winkler said cat fines levels are exceeding ISO8217:2017 specifications in fuel being bunkered in some areas, including the ARA region. But more common is that accumulated cat fines in tank sediments are being dispersed back into the tank and engine during operations, particularly in rough seas.

With higher viscosity IFO 380cst or IFO 180cst fuels, cat fines tend to be suspended in the denser liquid and are removed more easily by fuel separators. Low sulphur fuels have an average viscosity of 105cst, though it can be as low as 10cst. And this is resulting in cat fines sinking to the settling tank, where they can often undetected.