ANALYSIS OF MIDDLE DISTILLATE FUELS BY MIDBAND INFRARED-SPECTROSCOPY

A new analytical method based on infrared spectroscopy in the 4000-650 cm-1 wavenumber region has been developed that allows for rapid and reliable measurement of several pertinent fuel properties simultaneously. The method may be automated and, by using ruggedized commercially available Fourier transform infrared (FTIR) equipment, would be eminently suitable for commercial and military field applications. Preliminary studies show that middle region infrared spectroscopic data may be calibrated to determine those middle distillate fuel properties that are due to chemical structural features that give rise to active infrared resonance bands. The measured fuel property values must relate linearly to spectral intensities; i.e., they must obey Beer's law. In this study, the initially selected fuel properties were aromatic hydrocarbon content, carbon-to-hydrogen ratio, heat of combustion, cetane index, viscosity, and density. Other properties such as cloud point, pour point, octane number, cetane number, etc. are also expected to be successfully modeled. Usefulness of the method will be extended for the analysis of other fossil, as well as alternate fuels.