Understanding Shale Oil Hydrotreatment with Composition Analysis Using Positive-Ion Mode Atmospheric Pressure Photoionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Abstract

Positive-ion mode of atmospheric pressure photoionization (APPI) coupled with a 9.4 T Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer has been applied to the characterization of shale oil from pyrolysis and its hydrotreatment. The hydrotreated shale oil was obtained through reactions over catalysts Ni–Mo, Ni–W, or Co–Mo. It was found that N1 and N1O1 species are the dominant N compounds and S1 species is the dominant S compound in shale oil from pyrolyzing Huadian oil shale. The primary aromatic hydrocarbons (AHCs) are mono- and double-ring aromatics. After hydrotreatment, both S and N compounds are effectively removed and the catalyst Ni–Mo shows the best performance in hydrodesulfurization (HDS) and hydrodenitrogenation (HDN). The AHC species, especially the mono-ring aromatics, increases as a result of the transformation of N1, N1O1, and S1 species into AHC species through hydrotreatment. Indole, carbazole, acridine, and their derivatives are preserved as N1 species. The reactions of HDN for shale oil were further analyzed by considering the transformation between N1O1 and N1 species.