QUANTIFICATION OF PETROLEUM CARBON TYPES USING NMR AND FTIR SPECTROSCOPY
Dettman H. and Salmon S.
Optimization and trouble-shooting of petroleum production and refining processes require understanding the molecular interactions occurring during the process. In general, oils are sub-fractionated to resolve classes of molecular species, if not individual compounds, before analyses to correlate their molecular characteristics with upgrading or production behaviour. For example, distillation into desired boiling point cuts, followed by gas chromatography and mass spectrometry (GC-MS) are used to study distillate fractions [boiling point (bp) < 524EC (975°F)].
For analysis of residue fractions [boiling point (bp) > 524EC (975°F)], GC-MS has had limited use. However, liquid extraction and chromatography techniques such as “saturates-aromatics-resins-asphaltenes” [SARA] analyses and gel permeation chromatography for separation, together with the analytical techniques of nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy, are proving useful for quantifying carbon and heteroatom types in petroleum residues. The methods developed at NCUT will be described.