January 1, 2025Нефтехимия / Petroleum Chemistry0 citations

Composition and structure of asphaltenes and resins isolated from vacuum residue exposed to combined thermo- and hydrocracking process in suspension phase

Key Points

Asphaltenes exhibit a decreased molecular weight, showcasing notable changes compared to the initial vacuum residue.
The elemental analysis indicates a significant reduction of vanadium content, more than 30-fold in the hydrocracked product.
Assessment utilized various methods including MALDI mass spectrometry, TGA, EPR, and AAS for a thorough analysis.
Findings suggest new components formed from polycondensation of asphaltenes in the hydrocracking process.

Abstract

The composition of asphaltenes and resins of concentrated product of hydrocracked vacuum residue (CPHVR) obtained by the technology of combined thermal and hydrocracking in a suspension phase has been studied for the first time. The asphaltene content in CPHVR is 48.6 wt.%, and the resin content is 14.3 wt.%. Comparative analysis of asphaltenes and resins of CPHVR by IR spectroscopy, MALDI mass spectrometry, elemental analysis, TGA, EPR and AAS allowed us to compare their composition and structure with the corresponding components in the initial vacuum residue. It was shown that asphaltenes and resins of CPHVR differ from the corresponding components of the initial vacuum residue by a lower molecular weight, a higher proportion of aromatic and condensed structures and a more than 30-fold reduced content of vanadium and nickel. The obtained results suggest that the composition of asphaltenes and resins of CPHVR mainly contains new components formed due to polycondensation, as well as certain polyaromatic structures that cannot be converted into distillates under hydrocracking conditions.

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