Impacts of Biodiesel Blends on Fuel Filters Functions, Laboratory and Field Tests Results

From the end of the 90's, the use of biodiesel fuel (FAME) in blends with petroleum diesel fuel is increasing year after year with a minimum share of 10% defined by the European Parliament for 2020. In parallel, vehicle fleets working with B30 (EN590 - RME) have been developed in France under the impulsion of biodiesel fuel producers.

The aim of this investigation program was to determine the impacts of biodiesel fuel blends (higher than 20%) on diesel fuel filters regarding filter clogging and water separation efficiency.

Experiments show that high efficiency material with MFP 8μm are not presenting accelerated clogging during laboratory filtration tests with oxidized biodiesel fuels and this is confirmed by analysis of used diesel fuel filters from Euro 4 vehicle field tests using EN590 and B30 fuels.

Experiments also confirm higher stability of water droplet emulsions with biodiesel and lower water separation efficiency of coalescing and hydrophobic diesel fuel filters tested with these fuels. Moreover, measurements made on used filters in field tests from vehicles using B30 show complete loss of water separation efficiency (<20%) of filters after short mileages. Filter media analysis has correlated this phenomenon to a modification of the filter media hydrophobic characteristics because of FAME oxidation macro molecules deposited on the media fibers surface.