Investigation on thermal and storage stability of the Calophyllum inophyllum ester with natural leaf extract as antioxidant additive

Abstract

Biodiesel is a renewable and non-toxic fuel used in compression ignition engines as a blend with diesel without modifying the engine. It has a drawback of poor oxidation, thermal stability and long-term storage stability, preventing widespread use as a commercial fuel. The leaf extract with antioxidant properties will improve biofuel's stability by inhibiting the free radical formation or absorbing the free radicals. Natural antioxidants derived from natural products are the recent innovation in antioxidants. The present work analyses leaf extract's effect as additive with Calophyllum inophyllum methyl ester on thermal stability, storage stability, and oxidation stability. The addition of leaf extract has shown a significant improvement in thermal stability and reduced residual formation. 20 ml of the additive with biodiesel has improved the induction period of the B20 up to 9.2 h. On storage, the peroxide value, acid number, and viscosity have increased significantly due to oxidation, acid formation, and long-chain organic compounds, respectively. The additive addition has reduced the peroxide value, acid number, and viscosity by quenching the free radicals formed during biodiesel's oxidation.