Miscibility of ternary systems containing kerosene-based surrogate fuel and hydrous ethanol: Experimental data + thermodynamic modeling

Limited miscibility may be a major concern for the use of ethanol in jet fuels particularly when water is present. Herein miscibility data were obtained for mixtures composed of a kerosene-based surrogate fuel (80% n-decane and 20% 1,2,4-trimethylbenzene by mass), ethanol and water in varying percentages at −1.7 °C, 11.4 °C, 25 °C and 66 °C. The results indicated that the purity requirement of hydrous ethanol increased with the surrogate fuel percentage. The purity requirement increased when the temperature decreased. The upper limit for water tolerance was largely above the azeotropic value (4.4% water content) at 25 °C and 66 °C, which indicated that the blends can be miscible at room temperature and above even though water content is higher than the azeotrope concentration. In addition, emulsifier, in the low percent range (below 2% by volume), was shown to have notable effects on the phase behavior of the ternary mixtures. Liquid–liquid equilibrium (LLE) experimental data at 101.32 kPa were compared with simulation results by means of the UNIFAC-LLE model, which provided satisfactory results with moderate deviation from experimental data. A Matlab-based program was developed to determine the compositions of individual phases for any initial mixtures with known compositions.