Polar aromatic oxygen, sulfur and nitrogen compounds in diesel fuels are potential precursors for the formation of deposits in injection components. Therefore, a method for the analysis of the polar trace components in diesel fuels has been developed, modified and tested within the project. A total of 41 different diesel fuels according to DIN EN 590 were investigated with this method, including 17 B0 and 24 diesel fuel FAME blends with a FAME content < 7%(V/V). It could be shown that biodiesel in this concentration range does not interfere with chromatographic separation and enrichment steps of the target species. The polar components identified by GC-MS in the polar fuel fraction were assigned to 7 different structural groups. The relative sum content of polar components in the polar fraction and defined deposit precursors were correlated with results from the DDFT (Diesel Deposit Formation Test). Due to different deposit formation mechanisms and the strong influence of additives respectively biodiesel on the deposit thickness in the DDFT no correlation is found between these parameters, so that the influence of the polar species of the base fuel can be assessed as not significant on the basis of these investigations.
Technical Committee Automotive Fuels
Examination and evaluation of the content of polar species in diesel fuels with regard to their tendency to deposit formation
The IGF project (19871 BR) of the research association DGMK Deutsche Wissenschaftliche Gesellschaft für Erdöl, Erdgas und Kohle e.V., Überseering 40, 22297 Hamburg was funded by the Federal Ministry for Economic Affairs and Energy via the AiF within the framework of the programme for the promotion of joint industrial research (IGF) on the basis of a resolution of the German Bundestag.
Dr. rer. nat. Ulrike Schümann