Abstract: Molecular thermodynamic models and the properties of fluid phase equilibria are necessary to the design, running, control and optimization of industrial process and furthermore its precision and reliability are directly related to the modeling and optimization results of process simulation. In this context, an equation of state with variable range for square⁃well potential (SWCF⁃VR) was developed based on the statistical association fluid theory and applied to represent the thermodynamic properties like vapor⁃liquid equilibria (VLE), liquid⁃liquid equilibria, solid⁃liquid equilibria, enthalpy of vaporization or mixing and so on for traditional fluids, associated fluids, electrolyte solutions, ionic liquids, polymers, etc. At the same time, the equation of sate combining with surface tension and viscosity can be used to predict and calculate the transfer properties of the mixture such as surface tension and viscosity successfully. The salient feature in our model was that transferable molecular parameters fitted from experimental phase equilibria data or predicted from group contribution method or solvation calculation were used. Meanwhile, the test of theoretical model and determination of molecular parameters in SWCF⁃VR were carried out always based on experimental thermodynamic data. Thus, an online platform for fluid phase equilibria (www.equilibria.cn) were developed, where the details about phase behavior conception, classification and applications were summarized, and data searching systems and some softwares for VLE calculation provided. The mentioned thermodynamic model and online platform in this work could be well used for process design, modeling and optimization.

Key words: Phase equilibria, Equation of state, Molecular thermodynamics, Online platform, Transport properties

摘要： 　在流程工业中，热力学模型和相平衡数据是工业过程设计、模拟、控制及优化必不可少的要件，其准确性和精度直接决定过程设计、建模及控制优化的优劣。鉴于此，基于统计缔合流体理论，构建和发展了一变阱宽方阱链流体分子热力学模型，并将其成功应用到常规流体、缔合流体、电解质溶液、离子液体、聚合物等体系纯组分的PVT、混合物的汽（气）液平衡、液液平衡、固液平衡以及蒸发焓、混合焓等热力学性质的描述。同时，将该状态方程与表面张力、黏度等模型结合，可满意地预测和计算混合物表面张力、黏度等传递性质。在计算不同热力学性质中，采用了同一套分子参数，分子参数可来源于实验数据、基团贡献法或溶剂化法。另一方面，理论模型检验和模型参数的获得常依赖正确的热力学实验数据，为便于模型构建、应用和数据查询，开发了流体相平衡网络平台（www.equilibria.cn），并系统阐述了流体相平衡概念、分类、应用，提供了相平衡数据查询系统与计算软件。以上模型和网络平台的开发，为流程工业的模型化、智能化提供了基础理论和数据支撑。

关键词: 相平衡, 状态方程, 分子热力学, 网络平台, 传递性质