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Combined characterization using HT-GC × GC-FID and FT-ICR MS: A pyrolysis fuel oil case study

Djokic, Marko R., Muller, Hendrik, Ristic, Nenad D., Akhras, Abdul Rahman, Symoens, Steffen H., Marin, Guy B., Van Geem, Kevin M.
Fuel processing technology 2018 v.182 pp. 15-25
boiling, case studies, comprehensive two-dimensional gas chromatography, cracking, feedstocks, flame ionization, fractionation, fuel oils, mass spectrometry, petroleum, polycyclic aromatic hydrocarbons, pyrolysis, steam
In this work the composition of a hydrotreated distilled crude oil fraction (HTAL-FEED) and its heaviest steam cracking product fraction, the so-called pyrolysis fuel oil (HTAL-PFO), have been characterized in detail using high-temperature comprehensive two-dimensional gas chromatography (HT-GC × GC) coupled to a flame ionization detector (FID) and Fourier Transform-Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS). Moreover, the HTAL-FEED and HTAL-PFO were characterized using elemental analysis and SARA fractionation to determine their bulk properties. Although the main compounds are saturates, the HTAL-FEED contains significant amounts of aromatic compounds, primarily mono- and di-aromatics but even up to penta-aromatics, which are responsible for the growth of large polycyclic aromatic hydrocarbons (PAH) formed during steam cracking that almost entirely make up the HTAL-PFO product. Quantitative results are obtained based on the HT-GC × GC-FID chromatograms and the use of well-chosen internal standards, allowing ~90 wt% of the feedstock and ~60 wt% of HTAL-PFO to be quantified. FT-ICR MS analyses confirmed the presence of molecules heavier than penta-aromatics in the HTAL-FEED, as well as the very heavy character of HTAL-PFO consisting of highly condensed aromatic molecules with up to 16 fused aromatic rings. The analytical methodology can be applied to other steam cracking products, providing a near-molecular level insight into conversion and coke formation precursors during steam cracking of wide boiling range hydrocarbons.