locations will dissolve into biodiesel, and also if stationary engines can be run on the biodiesel containing certain levels of dissolved plastics. FAME is known to attack and quicken the ageing process of certain materials, including elastomers (which may be used as seals, valves, gaskets etc.) – materials should be checked for compatibility with FAME and FAME/ diesel blends by consultation with the equipment manufacturer.
Biodiesel in bunkers: On 15 June 2010 the fourth edition of the marine fuels standard, ISO 8217:2010, was issued. The previous edition of the marine fuels standard, ISO 8217:2005, required under point 5.1 of Section 5 – General Requirements that the fuels to be classified in accordance with the standard should be “homogeneous blends of hydrocarbons derived from petroleum refining.” This was interpreted as precluding the fuel from containing any bio-derived components. During the preparation of the fourth edition of the standard, the working group committee responsible for the production of the standard considered the topic of biodiesel and the potential for the material to find its way into the marine fuel supply chain. It concluded that it was almost inevitable that as a result of blending FAME into automotive diesel that some marine distillates and possibly even marine residual fuels may contain a proportion of FAME as a result of cross contamination within the distribution system (Source: Bunkerworld Forum 03/09/2009).
As such, the ISO
8217:2010 International Standard now additionally requires under point 5.4 of Section 5 – General Requirements that “The fuel shall be free from bio-derived materials other than ‘de minimis’ levels of FAME (FAME shall be in accordance with the requirements of EN 14214 or ASTM
D6751). In the context of this International Standard, ‘de minimis’ means an amount that does not render the fuel unacceptable for use in marine applications. The blending of FAME shall not be allowed.”
Annex A of the ISO 8217:2010 International Standard considers the issue of bio-derived products and FAMEs finding their way into marine fuels in more detail. Annex A states that notwithstanding the fact that FAME has “good ignition, lubricity properties and perceived environmental benefits”, there are “potentially specific
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complications with respect to storage and handling in a marine environment”, including:
● A tendency to oxidation and long term storage issues
● Affinity to water and risk of microbial growth ● Degraded low-temperature flow properties
● FAME material deposition on exposed surfaces, including filter elements.
It is recognised that there are a number of different sourced FAME products each with their own particular characteristics which may impact upon storage, handling, treatment, engine operations and emissions. The standard states that in “
...those instances where the use of fuels containing FAME is being contemplated, it should be ensured that the ship’s storage, handling, treatment, service and machinery systems, together with any other machinery components (such as oily-water separator systems) are compatible with such a product.”
The meaning of a ‘de minimis’ level is expanded upon in Annex A of the ISO 8217:2010 international standard. It is noted that determining a ‘de minimis’ level is not straightforward for a number of reasons, including the fact that there is no standardised analytical technique for detecting FAME materials in fuel oils and that, in most cases, sufficient data is not yet available with respect to the effects of FAME products on marine fuel systems. For the purposes of the International Standard, for the four grades of distillate fuel (DMX, DMA, DMZ & DMB when clear and bright) it is recommended that ‘de minimis’ be taken as “not exceeding approximately 0.1 volume %” when determined in accordance with test method EN 14078. For DMB when not clear and bright and for all categories of residual fuels, the standard notes that “... ‘de minimis’ cannot be expressed in numerical terms since no test method with formal precision statement is currently available. Thus, it should be treated as contamination from the supply chain system.”
Bioethanol
Bioethanol refers to ethanol produced by the fermentation of renewable sources of sugar or starch crops. Unlike FAME, bioethanol is a single chemical compound, the properties of which are well documented and understood. It is a volatile, colourless liquid which is miscible with water and also hygroscopic. Ethanol is the alcohol found in alcoholic beverages and is also commonly used as a solvent in perfumes, medicines and paints. However, the most
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