Fuel standards
100% biodiesel according to the common international standard for biodiesel EN 14214 is available at several fuel stations.
In Germany, the requirements for biodiesels are fixed in a DIN standard. There are standards for three different varieties of biodiesel, which are made of different oils:
- RME (rapeseed methyl ester, according to DIN E 51606)
- PME (vegetable methyl ester, purely vegetable products, according to DIN E 51606)
- FME (fat methyl ester, vegetable and animal products, according to DIN V 51606)
Characteristics
Biodiesel (FAME fatty acid ethyl ester) is consisting of different esters having a smaller boiling range , may have a slightly higher density (0.88 kg/l) and a lower heating value (89%) compared diesel. Cetane number and viscosity may be higher, the stochiometric air demand is lower (13.8 instead of 15), lubricity is higher compared to ultra low sulphur diesel but problems may occur at higher fuel temperatures with common rail injection pumps.
Most important the cold filter plugging point as most relevant figure (following the cloud and pour point) may be much higher compared to diesel which results in limits using pure biodiesel (FAME) in very cold climates. The absolute value depends on the feedstock.
The oxygen content reduces low soot emission caused by a very complete combustion, low sulphur content reduces the emission of particels.
The water hazard class is lower and 98% may be biodegradable within 3 weeks. As solvent there are problems with natural or butyl rubber an some (white) paints. Although most modern engines and fuel systems are prepared to use biodiesel, but only some models allow B100 usage.
Operational issues
Caused by the dilution potential of biodiesel for the motor oil, it should be chosen carefully according to manufacturers' recommendations and checked regularily. The suggested intervals for replacement of oil and filters should be observed carefully.
Check the motor oil level regularly -In case the oil level rises, replace the oil prematurely.
In addition to the items listed above, the stress on the engine has effects on oil dilution. In fact, oil dilution is at its maximum at low workloads of the engine.
When switching to biodiesel, deposits from earlier diesel fuels may be mobilised- so check fuel filters especially if you experience an engine power reduction.
Soaked rags should be stored in a fire safe area or dried individually to avoid spontaneous fire.
More Info
Biodiesel Industry Factsheets
EPA Fact Sheet
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