Corrosive character of Moringa oleifera Lam biodiesel exposed to carbon steel under simulated storage conditions

The corrosive character of Moringa oleifera Lam biodiesel was evaluated through static immersion tests with different carbon steels (CS1015 and CS4140) in absence and presence of the antioxidant tert-butylhydroquinone (TBHQ), at room temperature in the absence of light for 84 days. Biodiesel parameters, including oxidation stability (induction period, IP), total acid number (TAN) and iron concentration released from carbon steel, were monitored. The produced biodiesel presented an IP value of 4.9 h, which was increased to 6.2 h after the addition of 500 mg kg−1 TBHQ. After 84 days of immersion, IP values decreased in the first 21 days due to the contact with the metallic coupon, while TBHQ retarded this process. TAN value increased in 20% but the values were below the recommended limits ( 3 h) by the high Fe content.