F A M E (Fatty Acid Methyl Ester) in Distillate fuels

F A M E (Fatty Acid Methyl Ester)

ISO 8217:2005 marine fuel standard does not allow any bio-derived products to be blended into marine distillate or residual fuels. This, however, does not guarantee that a ship won’t be supplied with it, after all the physical supplier often does not know the quality of the fuel he is delivering and cross contamination is almost inevitable.

The latest revision of ISO 8217 is set to contain a new set of distillate fuels containing Fatty Acid Methyl Ester (FAME). FAME has previously been regarded as a contaminant in all marine fuels, but the new grades; DFA, DFZ and DFB allow up to 7% FAME content by volume.

CIMAC’s advice, issued prior to the latest draft of ISO 8217, says suppliers should specify that the blend supplied contains no more than 7% FAME, and otherwise meets normal ISO 8217 specifications. 

This requirement will be met by the new ISO 8217 biodiesel blend specifications.

Blends containing more than 2% biodiesel, or FAME, should undergo an additional stability test (EN15751) in addition to the one used for regular marine distillates (ISO 12205).

Biodiesel is currently much more expensive than oil-derived distillate fuels, so the supply of fuels with traces of FAME would likely be a result of shared supply infrastructure such as pipelines rather than it being added intentionally

The practice of blending FAME into conventional diesel and heating oils makes it almost inevitable that some distillate fuels supplied in the marine market will contain traces of FAME. Fuel testing agencies have reported that the presence of FAME is becoming more common in marine distillate stems.

Experience in recent years suggest distillate fuels containing 0.5% FAME do not cause any handling issues for ships

FAME will still be dealt with as a contaminant for the traditional distillate grades, DMA, DMB, DMZ, but the indicated ‘de minimis’ tolerance levels of FAME will shift from approximately 0,1% to 0.5% by volume.

Fame properties to watch out in case of ships supplied with blended distillates:

- Poor oxidation and thermal stability (Heightened risk of oxidation  due to water/ moisture content and stratification upon heating)

-Stable storage duration may be limited to as little as four weeks, although with the addition of additives this may be extended by 6-12 months -  with stratification issues in maintaining homogeneity of blends

-Solvent nature corrosive to certain metals and deteriorates rubber gaskets and tends to dislodge old deposits /sediments in pipelines and storage systems. This can cause handling issues on board by excessive sludge formation with filters choked due to sediment transport.

- Hydrophilic in nature - susceptible to microbial activity  , with poor flow characteristic at low temperatures.