The phase behaviour of six binary systems containing CO₂/propane/ethane with either tridecanoic or pentadecanoic acid were investigated. Bubble- and dew-point data were measured using the synthetic visual phase detection method using previously constructed variable volume view cells. The data were measured at temperatures between 310−410 K, with acid mass fractions 0.017−0.720. The results did not display temperature inversions, liquid-liquid equilibrium or three phase regions within the ranges investigated. The acids are most soluble in propane and least soluble in CO₂, possibly due to the asymmetry and molecular interactions present. Data for the solvent + uneven acid systems were modelled using the RK-ASPEN and CPA models in Aspen Plus®. The RK-ASPEN model was found to be better suited, but deviations between the experimental and modelled data were observed for the ethane and CO₂ systems. The model can therefore not be used to quantitatively correlate solubility data for systems with ethane/CO₂.

研究了六个含有CO ₂ /丙烷/乙烷与十三烷酸或十五烷酸的二元体系的相行为。使用合成的可见相检测方法，使用先前构建的可变体积视图单元，测量气泡和露点数据。在310-410 K之间的温度下测量数据，酸质量分数为0.017-0.720。结果未显示温度反转，液-液平衡或所研究范围内的三相区域。酸最易溶于丙烷，最不溶于CO ₂，可能是由于存在不对称和分子相互作用。使用AspenPlus®中的RK-ASPEN和CPA模型对溶剂+不均匀酸体系的数据进行建模。发现RK-ASPEN模型更合适，但是在乙烷和CO ₂系统中，实验数据和模型数据之间存在偏差。因此，该模型不能用于定量关联具有乙烷/ CO _2的系统的溶解度数据。