Engineering Research Center of Metallurgical Energy Conservation and Emission Reduction Ministry of Education, Kunming University of Science and Technology, Kunming, 650093, People's Republic of China.
Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, 650093, People's Republic of China.
Environ Sci Pollut Res Int. 2022 Jan;29(2):2432-2447. doi: 10.1007/s11356-021-15762-w. Epub 2021 Aug 9.
Iodine value (IV) is an indicator to evaluate the degree of unsaturation (DU) of biodiesel. It reflects the biodiesel degradation and oxidation stability (OS) and also has an effect on viscosity, low-temperature flow properties (LTFP), and the combustion performance. To construct a theoretical system for the simultaneous optimization of LTFP and OS of biodiesel using IV, 52 measured experimental data are used to investigate the qualitative and quantitative relationship between IV and biodiesel composition. The relationships between biodiesel physicochemical properties and IV are investigated in this work. The qualitative analysis shows that the poly-unsaturated fatty acid methyl esters (FAMEs) contribute to an increase in IV, whereas saturated and mono-unsaturated FAMEs decrease IV. Multiple linear regression (MLR) and artificial neural network (ANN) are used to estimate IV from FAMEs. The correlation coefficient, root mean squared error (RMSE), and mean absolute percentage error (MAPE) are respectively 0.976, 2.45, and 1.76% for the MLR model and 0.983, 2.14, and 1.57% for the back propagation neural network (BPNN) model; these values indicate the high accuracy of these methods. The performances of the proposed models were compared with three existing IV prediction models and validated by another databank. The results indicate that the application of the developed BPNN model is better and more comprehensive. Additionally, a preliminary conclusion is that biodiesel with a low percentage of both long-chain saturated and poly-unsaturated FAMEs can have solidifying point (SP) and OS in the proper range. Biodiesel with a low IV is generally more combustible and efficient.
碘值（IV）是评估生物柴油不饱和程度（DU）的指标。它反映了生物柴油的降解和氧化稳定性（OS），并对粘度、低温流动性能（LTFP）和燃烧性能有影响。为了构建一个使用 IV 同时优化生物柴油 LTFP 和 OS 的理论体系，利用 52 个实测实验数据来研究 IV 与生物柴油成分之间的定性和定量关系。本文研究了生物柴油理化性质与 IV 之间的关系。定性分析表明，多不饱和脂肪酸甲酯（FAMEs）会增加 IV，而饱和和单不饱和 FAMEs 会降低 IV。多元线性回归（MLR）和人工神经网络（ANN）用于从 FAMEs 中估算 IV。MLR 模型的相关系数、均方根误差（RMSE）和平均绝对百分比误差（MAPE）分别为 0.976、2.45 和 1.76%，反向传播神经网络（BPNN）模型分别为 0.983、2.14 和 1.57%；这些值表明这些方法具有很高的准确性。将所提出的模型的性能与三种现有的 IV 预测模型进行了比较，并通过另一个数据库进行了验证。结果表明，所开发的 BPNN 模型的应用更好且更全面。此外，初步得出的结论是，长链饱和和多不饱和 FAMEs 含量低的生物柴油可以具有适当范围内的凝点（SP）和 OS。IV 低的生物柴油通常更易燃且效率更高。
