烃-水体系互溶度预测模型的研究进展

Progress on prediction models of mutual solubility of hydrocarbon-water system

在化工、能源、环境、食品和药物等工业设计过程中,真实混合物的可靠溶解度数据非常重要,不仅能丰富相平衡数据库,还能指导工艺设备设计和产品质量控制。本文介绍了烃-水体系相互溶解度的模型化研究,包括状态方程法、活度系数法和经验关联式,以及近年来发展起来的真实溶剂似导体屏蔽模型法(conductor-like screening model for real solvents,COSMO-RS)。状态方程法和活度系数法主要是通过选择非对称的混合规则以及引进描述水分子极性作用的参数,来改善对烃-水体系相互溶解度的计算精度。经验关联式主要是对实验数据的拟合,每种烃的参数不同。COSMO-RS模型根据密度泛函理论(即建立极化电荷密度的简单经验式)计算单个分子嵌入虚拟导体产生的作用,通过准确描述界面统计相互作用获得体系的热力学性质。因此,该方法对各种体系具有普适性。分析表明,COSMO-RS模型对烃-水体系相互溶解度的预测值与实验值吻合良好,可以补充某些难以通过实验获得的烃-水体系互溶度数据。最后总结和展望了烃-水体系相互溶解度模型化的未来发展方向。

In chemical engineering,energy,environment,food and medical industry,reliable solubility data for real mixture is very important for process design,which can not only enrich the database of phase equilibrium,but also be greatly helpful for the design of process device and the fine control of products quality.It introduces the model of the mutual solubility on hydrocarbon-water system,including state equation methods,activity coefficient methods,empirical correlations and COSMO-RS（conductor-like screening model for real solvents） model developed in recent years.The state equation methods and activity coefficient methods are usually employed to improve the accuracy of the mutual solubility on hydrocarbon-water system according to the asymmetric mixing rules and the adjustment of the parameters describing the polarity of water molecules.The empirical correlations are mainly used to fit the experimental data,where the parameters of the correlations are different with respect to particular hydrocarbon system.Furthermore,the COSMO-RS model calculates the single molecule embedded virtual conductor based on the density functional theory by which the simple empirical polarization charge density is established.It is efficient and accurate for describing the statistical thermodynamic interactions of interface,and thus the features of thermodynamic qualities can be grasped conveniently.The results indicate that the predicted data of COSMO-RS model agrees well with the experimental one,which show the universality of COSMO-RS model in various kinds of systems,and thus providing an easy method for complementing the unmeasurable experimental data of mutual solubility for hydrocarbon-water system.The future directions for prediction models of the mutual solubility on hydrocarbon-water system are proposed.