Compositional Characterization of Pyrolysis Fuel Oil from Naphtha and Vacuum Gas Oil

Steam cracking of crude oil fractions gives rise to substantial amounts of a heavy liquid product referred to as pyrolysis fuel oil (PFO). To evaluate the potential use of PFO for production of value-added chemicals, a better understanding of the composition is needed. Therefore, two PFO’s derived from naphtha (N-PFO) and vacuum gas oil (V-PFO) were characterized using elemental analysis, SARA fractionation, nuclear magnetic resonance (NMR) spectroscopy, and comprehensive two-dimensional gas chromatography (GC × GC) coupled to a flame ionization detector (FID) and time-of-flight mass spectrometer (TOF-MS). Both samples are highly aromatic, with molar hydrogen-to-carbon (H/C) ratios lower than 1 and with significant content of compounds with solubility characteristics typical for asphaltenes and coke (i.e. n-hexane insolubles). The molar H/C ratio of V-PFO is lower than the one measured for N-PFO, as expected from the lower molar H/C ratio of the VGO. On the other hand, the content of n-hexane insolubles i...