Prediction of liquid–solid phase equilibrium for <scp> <i>n</i> </scp> ‐paraffinic systems in the presence of several crystalline structures

Abstract An algorithm is proposed to predict the number of solid phases and their crystalline structure in liquid–solid systems consisting of n‐ paraffins. By defining a fugacity coefficient of a given component for the entire multiphase system, the flash equations and stability analysis are combined into a single algorithm. It is shown that incorporation of the phase with the largest value of the composition summation yields the largest decrease in the free energy of the whole system. Multicomponent paraffinic mixtures are used to validate the proposed method. The predicted amount of solid, and the crystalline structure, agree with the experimental information. However, it is illustrated that a second solid phase may appear because of solid–liquid transition, and not because of a solid–solid transition as frequently assumed. Finally, for the most asymmetric mixtures, it is found that different solids with both structures may be present simultaneously.