Marine fuel instability on the rise in ARA

The stability of marine fuels available in the Amsterdam-Rotterdam-Antwerp (ARA) hub has deteriorated in the past month because of changing blend components and co-mingling, according to bunker trading firm Integr8 and fuel testing firm FOBAS.

The 0.5pc sulphur fuel oils tested in ARA have gone from being quite aromatic with higher density to being more paraffinic, which can only be as a result of co-mingling further up the supply chain, said Integr8's global manager for quality and claims Chris Turner. Co-mingling fuels of different origins can boost sediment levels, which make the blend unstable, and can form sludge, which can cause engine damage.

"ARA is concerning with high TSPs," Turner said, referring to total sediment potential — a measure of sediments left after a fuel is put under pressure and heated.

Integr8 recommends that buyers target stable fuels with low TSP, and that they obtain a recent certificate of quality. These certificates are usually two weeks old; certificates for fuel taken from floating storage could be as old as 2-3 months.

Fuel testing firm FOBAS said that there has been a significant increase in levels of Estonian shale oil being blended into 0.5pc fuel oil at ARA recently. FOBAS has not seen any change in contaminant-related fuel quality claims, but said that blending shale oil into marine fuels has caused problems in the past, with sludging around filters and during purification in ship engines.

What gets blended into marine fuels depends on what is available, and on economics. Integr8 said that as European gasoline demand started to slump with Covid-19 restrictions from March there was a rise in fuel oil's pour point, or the temperature at which it starts to behave as a fluid, because vacuum gasoil (VGO), unwanted in gasoline production, was increasingly being blended into the marine fuel pool.

More recently some refineries have switched back on their fluid catalytic crackers (FCCs), in response to a slight recovery in gasoline demand. Refiners could again need VGO as feedstock for FCCs to produce gasoline, but 0.5pc sulphur VGO continues to be sold into the marine fuel pool to be blended into 0.5pc fuel oil, which is compatible with the International Maritime Organisation (IMO) global sulphur limit.

By Erik Hoffmann