In this study, the phase behavior of a water + n-propanol + cyclohexane ternary mixture was experimentally investigated for feasibly using cyclohexane as an entrainer to the azeotropic distillation of a water + n-propanol azeotrope. The experimental results showed that this ternary mixture is partially miscible and exhibits as a heterogeneous azeotrope. The present experimental data include the binary water + n-propanol vapor-liquid equilibrium, the ternary water + n-propanol + cyclohexane vapor-liquid-liquid equilibrium, the heterogeneous azeotropic temperature, the bulk azeotropic liquid composition, and the individual liquid compositions at 760 mmHg. The correlation results of the binary data were satisfactory with the NRTL (AIChE J. 1968, 14, 135) and the UNIQUAC (AIChE J. 1975, 21, 116) models. The correlation result of the azeotropic ternary mixture with the NRTL model is fair, with the worst AARD % (10.69%) for the vapor composition of water and the AARD % values of the rest of the compositions smaller than 5%. The results with the UNIQUAC model show that the UNIQUAC model is not suitable to represent this azeotropic ternary system because of very large AARD % values. With the residual curve map (RCM) and the obtained liquid-liquid equilibrium curve, two conceptual azeotropic distillation schemes using cyclohexane as the entrainer were proposed to separate the azeotropic mixture of water and n-propanol. All of the thermodynamic properties required for constructing the RCM were obtained either from the literature or from the experiments performed in this study and include the boiling temperatures of all three constituent components, the azeotropic data of the constituent binary pairs, and the azeotropic data of the ternary system.