Evaluation of Chemical Functional Group Composition of Jet Fuels Using Two-Dimensional Gas Chromatography

The growing interest in fuel property prediction models for simplification of fuel characterization has led to techniques for evaluating the chemical functional group compositions of fuels and mixtures as low-dimensional representations of the more detailed complete fuel composition. A new technique for quantitatively evaluating the UNIFAC group composition, chosen for its predictive versatility, from two-dimensional gas chromatography (GC x GC) analysis of complex real and alternative jet fuels is discussed. GC x GC analysis provides a more detailed and comprehensive chemical composition for the extraction of chemical functional groups when compared to optical spectroscopy-based techniques like Fourier transform infrared and Raman spectroscopy. Furthermore, the operating cost is lower and GC x GC analysis is more direct than the NMR spectroscopic evaluation of functional groups. The conversion of GC x GC, time-of-flight mass spectrometry (TOF-MS), and flame ionization detection (FID) analysis data to UNIFAC group composition is done with a new method and software tool developed in this work. The tool can be decoupled from the fuel analysis method, used independently with other methods, and applied to already available fuel composition databases. Using GC x GC combined with TOF-MS and FID analysis, the UNIFAC group compositions of eleven different complex jet fuels are demonstrated as consisting of 10 groups of lower dimensional yet chemically significant features for data science prediction of fuel properties.