Studies on the effect of antioxidants on the long-term storage and oxidation stability of Pongamia pinnata (L.) Pierre biodiesel

This study investigates the impact of various synthetic phenolic antioxidants on the oxidation stability and storage stability of Pongamia (karanja) biodiesel (PBD). The results of Rancimat experiments show that the induction point (IP) increased substantially on adding certain antioxidants to the Pongamia biodiesel. The study reveals pyrogallol (PY) to be the best antioxidant to show the best improvement in the oxidative stability of PBD, the induction time being enhanced to 34.35 h at a PY concentration of 3000 ppm at 110 °C. The storage stability studies were carried out according to the ASTM standard procedures 1) ASTM D4625 at 30 °C/50 weeks and 2) ASTM D4625 at 43 °C/12 weeks by adding different antioxidants like BHT, BHA, PY, GA and TBHQ. The effectiveness of these five antioxidants on PBD was examined at varying loading levels during the storage period.