Fractionation of a vacuum residue with a mixture of CO₂-toluene as a method for characterizing heavy petroleum feedstocks

ABSTRACT

The characterization of the feedstock is an important analytical task in the modeling and development of processes for upgrading of petroleum residues. This work presents the results of fractionation of the vacuum petroleum residue by extraction using a mixture of CO₂ and toluene as a solvent. Fractionation was carried out by changing the ratio of components in the mixture by successively increasing the concentration of toluene in the composition of the CO₂ stream from 0% to 50%. As a result of separation of the vacuum residue, nine fractions of the extract with a yield of 83.1% were obtained.

Graphical abstract

KEYWORDS:

• carbon dioxide extraction
• fractionation method
• toluene

Acknowledgements

The authors thank the Engineering Center of the Moscow Institute of Physics and Technology (MIPT Center for Engineering and Technology) for the opportunity to use research equipment under the Agreement on Scientific and Technical Cooperation of March 2, 2015, as well as its staff for their help in analyzing the properties of samples of petroleum fractions.

Declaration of interest statement

The authors declare that they have no competing interests.

Abbreviations

EoS	=	equations of state
PC	=	pseudocomponent
PPR78	=	predictive Peng-Robinson 1978
VR	=	vacuum residues
SARA	=	saturates, aromatics, resins and asphaltenes
SFE	=	supercritical fluid extraction
SFEF	=	supercritical fluid extraction and fractionation
ABPR	=	automatic back pressure regulator
CO2	=	carbon dioxide
SC-CO2	=	supercritical carbon dioxide
CCR	=	Conradson carbon residue
RSD	=	relative standard deviation

Additional information

Funding

This work was financially supported by the Russian Foundation for Basic Research, project No. 18-33-00716 mol_a “Development of a new method for the fractionation of heavy oils and oil residues based on the process of supercritical fluid extraction (SFE).”