Are you ready for FAME?
With the advent of biodiesel blends in the marine fuels market, IBIA has received queries about what the impact may be.
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.*
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. This is for two reasons. Firstly, experience in recent years suggest distillate fuels containing 0.5% FAME do not cause any handling issues for ships, according to the latest draft international standard (DIS). Secondly, the DIS notes that 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. Indeed, some fuel testing agencies have reported that the presence of FAME is becoming more common in marine distillate stems.
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.
Distillate fuels with up to 7% FAME
In some locations the supply pool for marine distillates may be the same as for road diesel. In the US and EU, for example, such diesels could contain up to 7% FAME without being specifically labelled as biofuels.
Physical suppliers therefore need to take care to know the nature of the distillate fuels they offer. The first thing to ascertain is the fuel’s biodiesel content. This can be measured using ASTM test method D7371 or EN test method EN14078 (for clear and bright distillates).
Physical suppliers wanting to offer both regular distillates and blends with FAME would need to take care with their storage and distribution infrastructure, and may consider segregating fuel with up to 7% FAME to prevent excessive traces of FAME from being transferred to non-bio distillate fuels.
The International Council on Combustion Engines (CIMAC) has written a guide on what to expect, and which precautions to take, when using fuel blends containing 5-7% of FAME.**
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.
CIMAC also recommends that 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).
Both suppliers and ship operators can benefit from the advice on storage and handling in the guidance provided for ship operators in CIMAC’s guide.
Storage and handling
There is a risk of microbial growth for all distillate fuels, but the biodegradable nature of biofuel blends is thought to heighten this risk. There is also the potential for oxidation of biodiesel.
To reduce these risks, CIMAC’s advice is to avoid storing FAME blends for more than six months, and to take measures to reduce the risk of water entering or forming in tanks holding such fuels. Normal ‘good housekeeping’ routines should keep water ingress to a minimum.
On ships, the CIMAC guide says blends with up to 7% FAME can generally be stored and handled in the same storage and machinery used for conventional marine diesel fuels. But one aspect for ship operators to be aware of is that, because FAME blends have greater solvency than non-bio distillates, they have the potential for dislodging old deposits in fuel tanks and fuel lines, increasing sediment transport.
CIMAC therefore recommends paying particular attention to a possible rise in filter blocking frequency and fuel pump functionality when using biodiesel blends, as well as when ships are carrying out a changeover from a residual fuel oil to a distillate containing biodiesel.
For more advice on ‘good housekeeping’ to help handle FAME with confidence, please refer to the link below.**
If any of our members have experience with FAME they would like to share, please contact Unni Einemo on email@example.com
*For more information on the draft international standard: http://ibia.net/the-sixth-edition-of-iso-8127-is-coming/
**The CIMAC guide on handling distillate fuels with 5-7% FAME is available on http://www.cimac.com/publication-press/publications/wg-publications350/cimac-wg07-guideline-for-ship-owners-and-operators-on-managing-distillate-fuels.html