Prediction of Flash Temperature of Binary Mixtures Containing Alcohol–Alcohol and Alcohol–Acid Using a Combination of Activity Models and Group Contribution Methods

Abstract

The present paper aims to examine the method used to calculate the flash temperature of binary mixtures containing alcohol−alcohol and alcohol−acid based on activity models of Wilson, UNIQUAC and NRTL. The binary interaction parameter is obtained by group contribution method in these equations. The advantage of this method is that the methods used to calculate the flash temperature are based on the activity coefficients and the binary interaction parameter are independent from VLE experiments and phase equilibria. These parameters may be obtained from group contribution methods for calculation of flash temperature of binary mixtures containing alcohol. Therefore, 12 binary mixtures containing 97 binary flash data were used; for the three models of Wilson, NRTL, and UNIQUAC, adjustable parameters were obtained by a similar method using group contribution method and it was later tested for three activity equations and 4 mixtures containing 33 binary flash data. Test results indicate that the overall average absolute relative deviation and average absolute deviation for normal butanol/normal pentanol, normal pentanol/propionic acid, and isobutanol/propionic acid when the fitted coefficients are used by equilibrium data are, respectively, equal to 3.6 K and 1.11%, 1.39 K and 0.43%, and 1.11 K and 0.34%. When the binary interaction parameters were obtained using group contribution method (the present work), the results were, respectively, 1.03 K and 0.33%, 1.02 K and 0.32%, and 1.11 K and 0.35%. Moreover for isobutanol/normal pentanol mixture with equilibrium data, the group contribution method was solely applied which was highly consistent with experimental data on flash temperature.