Improvement of Oxidation Stability and Cold Flow Properties of Biodiesel Using Mixed Oil Strategy

Biodiesel's major limitations are its low-temperature performance and oxidation stability. This study analyses how different oil mixes affect biodiesel oxidation stability and cold flow properties (cloud and pour points). Three oils, namely, Jatropha, Karanja, and Palm oils, were selected for this investigation based on their chemical composition and availability, and their mixtures were formed. A simplex lattice mixture design model for biodiesel properties (oxidation stability, cloud point and pour point) was designed, and optimisation was carried out to achieve a set of objectives. The optimal mixed-oil ratio for Jatropha, Karanja, and Palm oil was found to be 8:57:35(% v/v), with desirability of 0.32, and the response values were observed to be compatible with biodiesel standards (EN 14214 and IS 15607). Optimal oils mix biodiesel oxidation stability was 8.5 h, better than Jatropha biodiesel (5.2 h) and Karanja biodiesel (7.5 h). Mixing oil improves biodiesel oxidation stability by 63% and 13% compared to Jatropha and Karanja biodiesel. Similarly, blended oil's biodiesel cloud point improves by 57% compared to Palm biodiesel. Oil-mixing technique balances saturated and unsaturated fatty acids and improves the oxidation stability and cold flow properties without chemical treatment. Graphical Abstract