Polar aromatic oxygen, sulphur and nitrogen compounds in diesel fuels are potential precursors for the formation of deposits in injection components. Within the scope of the project, a method for the analysis of polar trace components in diesel fuels has therefore been further developed and tested. A total of 41 different diesel fuels according to DIN EN 590 were examined with this method, including 17 fuels without biodiesel and 24 diesel fuel-biodiesel blends with a FAME content < 7%(V/V). It was shown that biodiesel in this concentration range did not interfere with chromatographic separation, fractionation and enrichment of the target components. The polar species identified by GC-MS in the polar fuel fraction were assigned to 7 different structural groups. The relative total content of polar components in the polar fuel fraction as well as defined deposit precursors were correlated with layer thickness results from the DDFT (Diesel Deposit Formation Test). Due to different deposit formation mechanisms as well as the strong influence of additives and biodiesel on the deposit layer thickness in the DDFT, there is no correlation 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