Calculation of Average Molecular Parameters, Functional Groups, and a Surrogate Molecule for Heavy Fuel Oils Using ¹H and ¹³C Nuclear Magnetic Resonance Spectroscopy

Heavy fuel oil (HFO) is primarily used as fuel in marine engines and boilers to generate electricity. Nuclear magnetic resonance (NMR) is a powerful analytical tool for structure elucidation, and in this study, 1H and 13C NMR spectroscopy were used for the structural characterization of two HFO samples. The NMR data were combined with elemental analysis and average molecular weight to quantify average molecular parameters (AMPs), such as the number of paraffinic carbon, naphthenic carbon, aromatic hydrogen, olefinic hydrogen, etc., in the HFO samples. Recent formulas published in the literature were used for calculating various derived AMPs, such as aromaticity factor (fa), C/H ratio, average paraffinic chain length (n), naphthenic ring number (RN), aromatic ring number (RA), total ring number (RT), aromatic condensation index (φ), and aromatic condensation degree (Ω). These derived AMPs help in understanding the overall structure of the fuel. A total of 19 functional groups were defined to represent the...