Robust Flash Calculation Algorithm for Microemulsion Phase Behavior

Saeid Khorsandi, Russell T. Johns

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


The HLD-NAC model was recently modified to match and predict microemulsion phase behavior experimental data for Winsor type III regions. Until now, the HLD-NAC model could not generate realistic phase behavior for type II− and type II+ two-phase regions, leading to significant saturation and composition discontinuities when catastrophe theory is applied. These discontinuities lead to significant failures in modeling surfactant applications. We modify the HLD-NAC equations to ensure consistency over the entire composition space including type II− and II+ regions. A robust and efficient algorithm is developed that always converges and provides continuous estimates with any formation variable of tie lines and triangles for all Winsor types. Discontinuities are eliminated and limiting tie lines near critical points are determined analytically. The tuning procedure is demonstrated using several sets of experimental data. Excellent predictability of tie lines and tie triangles, and solubilization ratios are shown.

Original languageEnglish (US)
Pages (from-to)1273-1287
Number of pages15
JournalJournal of Surfactants and Detergents
Issue number6
StatePublished - Nov 1 2016

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films


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