Abstract This work presents the use of a formal thermodynamic model together with UNIFAC activity coefficients model, without any further adjustable parameter, to predict the surface tension of biodiesel fuels based on the equality of chemical potentials between the vapor-liquid interface and liquid bulk. The biodiesel samples included in this work were reported previously in the open literature. They were produced from vegetable oils such as: canola, coconut, corn, cottonseed, hazelnut, lard, palm, peanut, rapeseed, safflower, soybean, sunflower, and Walnut. Surface tension values for 18 samples of binary, ternary and quaternary mixtures of fatty acid ethyl esters (FAEEs) at T = 298.15 were predicted with an average absolute relative deviation (AARD) = 1.39%. Surface tension values for 31 biodiesel samples composed by fatty acid methyl esters (FAMEs) were also predicted at temperatures from 303.15 K to 353.15 K. The AARD value obtained for the 78 experimental points of biodiesel samples was 1.86% which shows a very good agreement with experimental measurements. In the UNIFAC method, predictions of surface tension values for the mixtures are based on the knowledge of the values of the surface tension for the pure components; these values were obtained from different sources. Also, two simple mixing rules on mass and mole fraction basis were used to predict the surface tension of biodiesel fuels. The AARD value obtained from the comparison between experimental and calculated values were: 2.77% and 2.91% for mixing rules on mass and mole fractions, respectively.

中文翻译：

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使用 UNIFAC 活性系数预测脂肪酸乙酯和生物柴油燃料混合物的表面张力

摘要 这项工作提出了使用正式的热力学模型和 UNIFAC 活度系数模型，没有任何进一步的可调参数，基于汽液界面和液体体积之间化学势的相等性来预测生物柴油燃料的表面张力。这项工作中包含的生物柴油样品先前已在公开文献中报道过。它们由植物油制成，例如：油菜籽、椰子、玉米、棉籽、榛子、猪油、棕榈、花生、油菜籽、红花、大豆、向日葵和核桃。预测了 18 个脂肪酸乙酯 (FAEE) 的二元、三元和四元混合物样品在 T = 298.15 时的表面张力值，平均绝对相对偏差 (AARD) = 1.39%。31 个由脂肪酸甲酯 (FAME) 组成的生物柴油样品的表面张力值也在 303.15 K 至 353.15 K 的温度下进行了预测。从生物柴油样品的 78 个实验点获得的 AARD 值为 1.86%，这表明与实验测量。在 UNIFAC 方法中，混合物的表面张力值的预测基于纯组分表面张力值的知识；这些值是从不同来源获得的。此外，基于质量和摩尔分数的两个简单混合规则用于预测生物柴油燃料的表面张力。从实验值和计算值之间的比较中获得的 AARD 值分别为：质量分数和摩尔分数的混合规则分别为 2.77% 和 2.91%。