Analysis: Bunker spec uncertainty looms in 2020

Lack of clarity persists for marine fuel specification plans after January 2020,even as the industry is now one year away from implementing the International Maritime Organization's (IMO) global marine fuel sulphur cap of 0.5pc.

With numerous types of blends being tested, it will take until the second half of 2020 for the industry to discern the prevalent 0.5pc sulphur bunker specifications and gauge compatibility.

The specifications are expected to be compliant with the International Organization for Standardization (ISO) 8217:2017 guidance, but at the start of 2020, there will be lack of important details such as the typical density, typical viscosity and typical pour point.

The specification and price uncertainly is creating anxiety for shipowners and charterers. Problems with contaminated bunkers this summer, originating in the US Gulf and spreading to Panama and Singapore, has not helped suppliers' case for using experimental blends.

Some shipowners who are unable to justify scrubber investments have announced that they will burn conventional marine gasoil (MGO) to meet the regulation. MGO is the more expensive fuel option, but shipowners trust it will not damage their vessels' engines and fuel pumps, and regardless of its origin, it can be safely mixed in their tanks.

Suppliers such as BP, Shell and ExxonMobil are working to patent their blends, but there is no consensus among the different companies what the new 0.5pc sulphur fuel will look like.

One major supplier, Exxon Mobil, has included details about its planned IMO-compliant bunker fuel in patent number 9,920,270, filed with the US Patent and Trademark Office in March 2018. The patent describes low-sulphur bunker fuel made up of uncracked, hydrotreated vacuum resid. To produce the marine fuel, the vacuum resid is first hydrotreated, which removes at least 80pc of its sulphur content resulting in a product with about 0.12-0.14pc sulphur. Then the uncracked, hydrotreated vacuum resid is typically used as feedstock in a refinery's fluid catalytic cracking (FCC) unit to make gasoline. But some of the vacuum resid can be diverted from the FCC unit to be used directly as bunker fuel or blended with diesel and then used for bunkering. In addition to the 0.12-0.14pc sulphur content, the uncracked, hydrotreated vacuum resid has viscosity of about 442cst at 50˚C, pour point of about 24˚C, density of about 945 kg/m3 at 15˚C, flash point of over 180˚C, aluminum and silicon content of about 8 mg/kg and vanadium content about of 4 mg/kg. The vacuum resid specifications fit the ISO fuel standard for heavy bunker fuel with maximum viscosity of 500cst. The vacuum resid can be blended with diesel to reduce the viscosity.