Skuld Marine Fuels Integrate Cashew Nutshell Liquid Biofuel

With strict decarbonization rules already enforced in the EU/EEA, European authorities are now honing in on greenhouse gas emissions from ships operating in these waters, as well as the GHG intensity of the fuels they use.

Once the 2023 IMO Strategy on Reduction of GHG Emissions from Ships is fully implemented, this scrutiny will extend to a broader geographic area.

The shipping industry is urged to shift towards low- or zero-carbon fuels, including various biofuels. One such alternative under investigation is Cashew Nutshell Liquid (CNSL), a potential ‘drop-in’ fuel option.

CNSL is a byproduct of cashew nuts and offers a cost-effective renewable fuel alternative. Despite its benefits in enhancing fuel blend lubricity and energy content, CNSL’s high acidity makes it highly corrosive and its combustion properties suboptimal. It also contains phenolic compounds that tend to polymerise, leading to instability.

Recently, Skuld has received reports from several vessels encountering operational problems primarily linked to the fuel system. Issues such as injector failures, clogged filters and heaters, fuel sludging, and deposit build-up—stemming from fuel contamination—have been observed.

Extended Gas Chromatography Mass Spectrometry (GCMS) tests on Heavy Fuel Oil (HFO) and Very Low Sulphur Fuel Oil (VLSFO) samples revealed elevated levels of phenolic compounds, including cardol, cardanol, and anacardic acid.

Fuel blends containing CNSL can cause serious issues for engine components, such as accelerated wear of fuel pump parts, cracks within fuel systems, and reduced engine performance, all of which may lead to a loss of power.

Skuld advises its members and assured parties to conduct thorough due diligence when ordering or procuring bunkers.