In this work, we systematically study the phase behavior of the binary systems homologous series of methane with heavier n-alkanes, by considering the appearance of fluid and pure solid phases. The Peng-Robinson (PR) and the generalized Redlich–Kwong–Peng–Robinson (RK-PR) equations of state (EoS) are coupled to a solid fugacity model which considers the solid phase as only formed by the pure heavy compound. Correlations are developed here for all the solid fugacity model parameters, as functions of the n-alkane carbon number; and a high-quality reproduction of the melting curves of pure n-alkanes is obtained. Furthermore, diagrams of the global phase behavior, as well as solid-fluid isopleths, in wide ranges of conditions are computed through numerical continuation methods. The evaluation and comparison of results show that both PR and RKPR, associated to the solid fugacity model with the correlations here developed, are able to correctly predict the solid-fluid phase behavior of the studied mixtures along the methane + n-alkane series, although the predictions obtained with the RK-PR model are more accurate, especially for the more asymmetric systems.

在这项工作中，我们通过考虑流体相和纯固相的出现，系统地研究甲烷与更重的正构烷烃的二元系统同源系列的相态。Peng-Robinson（PR）和广义Redlich-Kwong-Peng-Robinson（RK-PR）状态方程（EoS）与固体逸散模型耦合，该模型将固相视为仅由纯重化合物形成。此处针对所有固体逸度模型参数建立了相关性，作为正构烷烃碳数的函数。并获得高质量的纯正构烷烃熔解曲线图。此外，通过数值连续方法，可以计算出大范围条件下的整体相行为以及固相流体等值线图。结果的评估和比较表明PR和RKPR