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 N 1 and N 1 O 1 species are the dominant N compounds and S 1 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 N 1 , N 1 O 1 , and S 1 species into AHC species through hydrotreatment. Indole, carbazole, acridine, and their derivatives are preserved as N 1 species. The reactions of HDN for shale oil were further analyzed by considering the transformation between N 1 O 1 and N 1 species.

Recent Advances in Petroleum Analysis by Mass Spectrometry

“…The abundance of the nitrogen-containing compounds was found to be significantly reduced upon both HDT and FCC. These results were in agreement with those of Zhang et al, who employed (+) APPI 9.4 T FTICR MS to show that nitrogen- and sulfur-containing compounds were effectively removed from a shale oil upon HDT using a NiMo-based catalyst …”

“…These results were in agreement with those of Zhang et al, who employed (+) APPI 9.4 T FTICR MS to show that nitrogen-and sulfur-containing compounds were effectively removed from a shale oil upon HDT using a NiMo-based catalyst. 113 Models that can predict the total nitrogen content in crude oil before and after a treatment based on measured mass spectra would be useful in determining the efficiencies of different treatments. Terra et al utilized partial least-squares regression with variable selection based on competitive adaptive reweighted sampling (CARSPLS) to create a model for the prediction of the content of basic nitrogen compounds in crude oils based on data obtained using (+) LDI 9.4 T FTICR MS. 114 The model was built based on the relative abundances of molecular ions of 48 basic nitrogen-containing compounds in the mass spectra measured for 50 crude oils.…”

Application of Laser-Desorption Silver-Ionization Ultrahigh-Resolution Mass Spectrometry for Analysis of Petroleum Samples Subjected to Hydrotreating

“…In HDS, it was reported that the C–S bonds in the sulfur-containing compounds were cleaved by the addition of hydrogen (H) and were converted into HCs. − By comparing Figures and in the case of AR1/tAR1 and AR2/tAR2 samples, it can be deduced that the increased amount of HC compounds in treated oils resulted from the transformation of sulfur compounds during the HDS. Because the sulfur-containing compounds with DBE < 9, are easier to hydrogenolyze than compounds with DBE > 9, benzothiophene-type compounds of DBE values from 6 to 8 and thiophinobenzothiophene-type compounds of DBE values from 8 to 10 were easily converted into aromatic HCs of DBE values from 4 to 7.…”

Transformation of Basic and Non-basic Nitrogen Compounds during Heavy Oil Hydrotreating on Two Typical Catalyst Gradations

“…Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) is considered an effective method to identify complex organic compounds in various petroleum fractions, especially heavier fractions. − Different ionization sources, such as atmospheric pressure photoionization (APPI) and electrospray ionization (ESI) coupled with FT-ICR MS, having advantages of high resolution and good sensitivity, − have been successfully utilized to identify hydrocarbons, non-hydrocarbons, and metal compounds in a variety of petroleum fractions. − Different compounds in heavy petroleum fractions can be ionized by different techniques, but the effect on others is not obvious. Because APPI is a nonselective method that can ionize many types of molecules, it provides a general overview of the species in heavy petroleum fractions, whereas ESI is more selective for polar species and presents a basic character in the positive mode and an acidic character in the negative mode.…”