Abstract The paper is the first of a series of two articles on molecular models for alkanes with air components and combustion products. This article reports simulations of the vapor-liquid equilibrium phase diagram for mixtures of linear hydrocarbons with nitrogen, carbon dioxide and water. We consider four alkanes: methane, propane, octane and dodecane as characteristic components of natural gas, liquefied natural gas, gasoline and kerosene. Combustion products are presented with common computationally inexpensive molecular models: three-center models for N2 and CO2, TIP4P-2005 model for water, and united-atom forcefield for alkanes. The parameters for nitrogen, CO2 and water oxygen interactions with CH2 and CH3 groups are calculated with Lorentz-Berthelot mixing rules with an adjustable coefficient for the energy parameter e, a single temperature-independent coefficient for each non-alkane component. We obtained very reasonable agreement with the experimental data for most alkane-nitrogen and alkane-carbon dioxide binary mixtures and discuss in detail the capability of the models with unified adjustable parameters. For dodecane-water system, reasonable agreement between calculated solubility of water in dodecane and experimental data was obtained; the model however is unable to represent the near-critical and high pressure phase boundaries.

中文翻译：

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烷烃与空气组分和燃烧产物相平衡的分子模型 I. 烷烃与氮气、CO2 和水的混合物

摘要 本文是关于具有空气成分和燃烧产物的烷烃分子模型的两篇系列文章中的第一篇。本文报告了直链烃与氮气、二氧化碳和水混合物的汽液平衡相图的模拟。我们认为四种烷烃：甲烷、丙烷、辛烷和十二烷是天然气、液化天然气、汽油和煤油的特征组分。燃烧产物采用常见的计算成本低廉的分子模型：N2 和 CO2 的三中心模型、水的 TIP4P-2005 模型和烷烃的联合原子力场。氮、CO2 和水氧与 CH2 和 CH3 基团相互作用的参数使用 Lorentz-Berthelot 混合规则计算，能量参数 e 具有可调系数，每个非烷烃组分的单一温度无关系数。我们与大多数烷烃 - 氮和烷烃 - 二氧化碳二元混合物的实验数据获得了非常合理的一致，并详细讨论了具有统一可调参数的模型的能力。对于十二烷-水体系，计算出的水在十二烷中的溶解度与实验数据具有合理的一致性；然而，该模型无法表示近临界和高压相边界。计算出的水在十二烷中的溶解度与实验数据之间取得了合理的一致性；然而，该模型无法表示近临界和高压相边界。计算出的水在十二烷中的溶解度与实验数据之间取得了合理的一致性；然而，该模型无法表示近临界和高压相边界。