表面张力预测小桐子生物柴油氧化程度的应用与分析

Application and Analysis of Surface Tension Prediction of Oxidation Degree of Jatropha Biodiesel

采用Rancimat法在110℃下对小桐子生物柴油进行不同时间的加速氧化降解,利用GC-MS技术、酸值滴定等手段研究了用表面张力检测燃料氧化程度的适用性。通过对实验数据分析表明:小桐子生物柴油经加速氧化后生成醛、酮、相对分子质量较高的含氧化合物及可溶性聚合物;其表面张力、酸值以及密度在氧化14 h后分别增加了9.1%、551%和3.8%;经相关性分析得到氧化后小桐子生物柴油表面张力与酸值的相关系数为0.99。基于此提出了4种利用表面张力预测小桐子生物柴油氧化程度的模型,并采用留一交叉验证法进行了检验分析,通过比较均方根误差(RMESP)值、相关系数R值,最终确定对数模型精确度以及相关性较高,其RMESP值以及相关系数R值分别为0.0937、0.9879,并且酸值预测值与实际值的误差为2.95%,说明通过表面张力可以预测小桐子生物柴油的氧化程度。

In this study,the calcination and oxidation of Jatropha biodiesel was carried out at 110℃and different time by using the Rancimat method.The applicability of surface tension in detecting the oxidation degree of fuel was studied by means of GC-MS and acid value titration.The analysis of experimental data shows that the Jatropha biodiesel undergoes accelerated oxidation to form aldehydes,ketones,high relative molecular mass oxygenates and soluble polymers,and its surface tension,acid value and density increase by 9.1%,551%and 3.8%respectively;the correlation between the surface tension and acid value of Jatropha biodiesel after oxidation is 0.99.Based on this,four prediction models for predicting the degree of fuel oxidation using surface tension were proposed,and the test was carried out by leaving the cross-validation method.Comparing the RMESP value and the correlation coefficient R value,the final model is logarithm model,with the RMESP value and the correlation coefficient R being 0.0937 and 0.9879 respectively,and the error of predicted value and experimental value being 2.95%,indicating that the surface tension can be used to predict the degree of oxidation of the fuel.