Experimental study and thermodynamic modeling of solid-liquid equilibrium of binary and ternary mixtures formed by C11H24, C12H26 and C14H30 for cryogenic thermal energy storage

Abstract

Abstract In this study, experimental investigations of solid-liquid phase diagram of binary and ternary mixtures formed by the C11H24, C12H26 and C14H30 were carried out to employ the potential phase change materials (PCMs) for cryogenic applications using the differential scanning calorimetry (DSC). In addition, the thermodynamic equilibrium was modeled employing the ideal model, and the Wilson and NRTL model were applied to correlate the liquidus line. The results show that the C11-C12 system exhibits a peritectic transition and the composition of possibly peritectic point is 60wt% C12 with the temperature of 251.65 K. The compositions of the eutectic points appear at 10wt% C14 for C11-C14 system and 18wt% C14 for C12-C14 system with eutectic temperatures of 246.85 K and 260.45 K, respectively. The C11-C12-C14 ternary system presents two possibly eutectic points at compositions of 67wt% C11/5wt% C12 and 86wt% C11/10wt% C12 with eutectic temperatures of 246.45 K and 248.05 K, and has the slight supercooling (1.7 ˚C and 0.5 ˚C), indicating miscibility in liquid phase and immiscibility in solid phase. Moreover, the liquidus lines calculated by the theoretical models are in good agreement with the experimental results. The best predicted results of the ternary mixture and C11-C12 binary subsystem are obtained by the ideal model, with deviations of 0.75% and 0.58% respectively.