This test method covers the determination of total cycloparaffins and total aromatics in synthetic paraffinic kerosene fuels (SPK) in the boiling range of 69C to 350C using comprehensive two-dimensional gas chromatography (GCxGC) coupled with a flame ionization detector (FID). It is intended for the analysis of SPK fuels containing from 0.5 to 30 mass-% total cycloparaffins and 0.02 to 10 mass-% total aromatics. Molecular type groups are identified by their location, as plotted on a chromatographic contour plot image. Alkenes and compounds containing sulfur, nitrogen and oxygen are possible interferents.
D7566 Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons contains specifications for synthetic paraffinic kerosene, or SPK, a fuel composed primarily of normal paraffins, isoparaffins, a lesser amount of cycloparaffins, and a low level of aromatics. A research report has shown that high-quality SPK aviation fuels are produced from Fischer-Tropsch synthesis processes followed by hydroprocessing. Recently, hydroprocessed renewable jet (HRJ) SPK fuels have been produced from animal fats and plant oils with properties equivalent to the well tested FT SPK fuels. In order to ensure that SPK fuels produced from different processes all have similar properties, D7566 (Table A1-2) contains specification limits for maximum amounts of cycloparaffins and aromatics in SPK fuels. The properties specified in Table A1-2 only have to be measured for a new or modified process to produce SPK and will not be required for each batch of SPK fuel. The current method specified for measurement of cycloparaffins and aromatics in Table A1-2 is D2425, an MS method not originally developed for such highly paraffinic fuels. While D2425 can be used for such measurements, it must be accompanied by the appropriate inclusion of standards which can make the test itself lengthy and complicated. Also, D2425 is not widely available through numerous contract labs. Because of the complexity and limited availability of D2425 for measurement of cycloparaffins and aromatics in SPK fuels we propose the development of a GCxGC method as an alternative method for measurement of such hydrocarbon groups. When available, this new GCxGC method can be included as an optional method for the measurement of cycloparaffins and aromatics in future revisions of the specification.
Keywordsaromatics; cycloparaffins; GCxGC; synthetic paraffinic kerosenes
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Draft Under Development