Izvorni znanstveni članak

https://doi.org/10.5562/cca2612

NMR and Chemometric Characterization of Vacuum Residues and Vacuum Gas Oils from Crude Oils of Different Origin

Jelena Parlov Vuković orcid.org/0000-0002-8464-5599 ; INA-Industrija nafte d.d., Refining & marketing business division, Product development department, Lovinčićeva 4, 10002 Zagreb, Croatia
Predrag Novak ; University of Zagreb, Faculty of Science, Department of Chemistry, Horvatovac 102a, HR-10000, Zagreb, Croatia
Janez Plavec ; NMR Center, National Institute of Chemistry, SI-1000 Ljubljana, Slovenia
Miha Friedrich ; NMR Center, National Institute of Chemistry, SI-1000 Ljubljana, Slovenia
Ljiljana Marinić Pajc ; INA-Industrija nafte d.d., Refining & marketing business division, Product development department, Lovinčićeva 4, 10002 Zagreb, Croatia
Tomica Hrenar ; University of Zagreb, Faculty of Science, Department of Chemistry, Horvatovac 102a, HR-10000, Zagreb, Croatia

Sažetak

NMR spectroscopy in combination with statistical methods was used to study vacuum residues
and vacuum gas oils from 32 crude oils of different origin. Two chemometric metodes were applied. Firstly,
principal component analysis on complete spectra was used to perform classification of samples and
clear distinction between vacuum residues and vacuum light and heavy gas oils were obtained. To quantitatively
predict the composition of asphaltenes, principal component regression models using areas of resonance
signals spaned by 11 frequency bins of the 1H NMR spectra were build. The first 5 principal components
accounted for more than 94 % of variations in the input data set and coefficient of determination
for correlation between measured and predicted values was R2 = 0.7421. Although this value is not significant,
it shows the underlying linear dependence in the data. Pseudo two-dimensional DOSY NMR experiments
were used to assess the composition and structural properties of asphaltenes in a selected crude oil
and its vacuum residue on the basis of their different hydrodynamic behavior and translational diffusion
coefficients. DOSY spectra showed the presence of several asphaltene aggregates differing
in size and interactions they formed. The obtained results have shown that NMR techniques in combination
with chemometrics are very useful to analyze vacuum residues and vacuum gas oils. Furthermore, we
expect that our ongoing investigation of asphaltenes from crude oils of different origin will elucidate in
more details composition, structure and properties of these complex molecular systems.

Ključne riječi

NMR; PCA; PCR; crude oils; vacuum residues and gas oils; asphaltenes

Hrčak ID:

139134

URI

https://hrcak.srce.hr/139134

Datum izdavanja:

27.3.2015.

Posjeta: 3.760 *