Robust Flash Calculation Algorithm for Microemulsion Phase Behavior

• Published in: Journal of surfactants and detergents 2016-11, Vol.19 (6), p.1273-1287
• Main Authors: Khorsandi, Saeid, Johns, Russell T.
• Format: Article
• Language: English
• Subjects: Algorithms; Aquatic Pollution; Chemistry; Chemistry and Materials Science; Experimental data; Flash; HLD‐NAC; Industrial Chemistry/Chemical Engineering; Microemulsion; Microemulsions; Original Article; Phase behavior model; Phase transitions; Physical Chemistry; Polymer Sciences; Simulation; Surfaces and Interfaces; Surfactant; Surfactants; Thin Films; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 1097-3958; 1558-9293
• DOI: 10.1007/s11743-016-1877-9

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.