Modeling of asphaltene precipitation from n-alkane diluted heavy oils and bitumens using the PC-SAFT equation of state

María A. Zúñiga-Hinojosa, Daimler N. Justo-García, Marco A. Aquino-Olivos, Luis A. Román-Ramírez, Fernando García-Sánchez

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

In this work, the PC-SAFT equation of state was applied to the modeling of asphaltene precipitation from n-alkane diluted heavy oils and bitumens. Liquid-liquid equilibrium was assumed between a dense liquid phase (asphaltene-rich phase) and a light liquid phase. The liquid-liquid equilibrium calculation, in which only asphaltenes were allowed to partition to the dense phase, was performed using an efficient method with Michelsen's stability test. The bisection or Newton-Raphson method was used to improve convergence. Experimental information of the heavy oils and bitumens, characterized in terms of solubility fractions (saturates, aromatics, resins, and asphaltenes), was taken from the literature. Asphaltenes were divided into fractions of different molar masses using a gamma distribution function. Predictions of the PC-SAFT equation of state using linear correlations of the binary interaction parameters between asphaltene subfractions and the n-alkane were compared with the measured onset of precipitation and the amount of precipitated asphaltene (fractional yield) of the heavy oils and bitumens diluted with n-alkanes. Results of the comparison showed a satisfactory agreement between the experimental data and the calculated values with the PC-SAFT equation.

Original languageEnglish
Pages (from-to)210-224
Number of pages15
JournalFluid Phase Equilibria
Volume376
DOIs
StatePublished - 25 Aug 2014
Externally publishedYes

Keywords

  • Asphaltene precipitation
  • Equation of state
  • Liquid-liquid equilibrium
  • Onset
  • PC-SAFT

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