Evaluation of the oxidative stability and flow properties of quaternary mixtures of vegetable oils for biodiesel production

Abstract

Currently, biodiesel, a biofuel obtained from vegetable oils or animal fats, is becoming increasingly important in power generation. The properties of biodiesel are tied to the chemical composition of the oil or fat from which it was obtained. Esters prepared with saturated fatty acids have a high cloud point, high viscosity, while the unsaturated esters are less viscous and more easily oxidized. In this sense, the present study aimed to evaluate the oxidative stability as well as the hydrodynamic properties of quaternary mixtures of soybean (SBO), cotton (CTO), jatropha curcas (JCO) and babassu oils (BBO). The samples M4O (12.50 JCO:25.00 SBO:12.50 CTO:50.00 BBO, w/w%) and SBO showed the best kinematic viscosities, while the samples M1O (16.67 JCO:33.33 SBO:33.33 CTO:16.67 BBO, w/w%) and CTO showed the best pour point and fluidity point. The oxidation induction time (OIT) was measured using pressure differential scanning calorimetry (PDSC) and also Rancimat and Petro-Oxy apparatuses. The replacement of the studied individual oils by their quaternary mixtures was shown to improve the deficiencies of the individual oils. Among the individual oils, BBO displayed the highest and CTO the lowest OIT values. As for the mixtures, the best and the worst OIT were M4O and M1O, respectively. When the oxidative stability and cold flow properties were analyzed together, the sample that showed the best performance of them all was M3O (14.29 JCO:42.86 SBO:14.29 CTO:28.56 BBO, w/w%).