The oxidative stability of biodiesel: Effects of FAME composition and antioxidant

Abstract

A significant problem associated with the commercial acceptance of biodiesel is poor oxidative stability. This study investigated the effectiveness of individual and binary antioxidants to improve the oxidative stability of different types of biodiesel and distilled biodiesel. Results indicate that different types of biodiesel have different levels of oxidative stability, and that natural antioxidants and FAME composition play significant roles in determining oxidative stability. Synthetic antioxidants can enhance the oxidative stability of different types of biodiesel, and antioxidant activity increases as a function of its concentration. However, the effective activity level of antioxidant is dependent on biodiesel feedstock. Binary antioxidant formulations (TBHQ and PY) have a synergistic effect on oxidative stability of biodiesel. After long-term storage at room temperature, the oxidative stability of untreated SBO-based biodiesel significantly decreases as a function of time, while the addition of the antioxidant TBHQ can improve and maintain oxidative stability of biodiesel over an 18-month period. However, the effectiveness of PY significantly decreases even after 2-months.

Impact of antioxidant additives on the oxidation stability of biodiesel produced from Croton Megalocarpus oil

“…To increase the oxidation stability of COME, it was doped with stabilizers or antioxidants. These were selected on the basis of their chemical structure, quality, cost, availability as well as previous studies on biodiesel and vegetable oils used in the food industry [21][22][23]. The antioxidants chosen for this study were 1,2,3 tri-hydroxy benzene (Pyrogallol, PY), 3,4,5-tri hydroxy benzoic acid (Propyl Gallate, PG) and 2-tert butyl-4-methoxy phenol (Butylated Hydroxyanisole, BHA).…”

Evaluation of Peanut Fatty Acid Methyl Ester Sprays, Combustion, and Emissions, for Use in an Indirect Injection Diesel Engine

“…The biodieseloxidation stability has been found in this study to be lower than the standard. 24, 25 Tang et al 6 found that antioxidants improved the oxidation stability of biodiesel, suggesting that antioxidants could be added to the FAMEs in the present study to improve the oxidation stability. Moser 7 determined that methyl esters that contained 10 or less carbons in the fatty acid backbone were unacceptable for stability analysis at 110°C (EN 14112) due to excessive sample evaporation, but the FAME used in this study had more than 10 carbons that allowed for proper oxidation stability determination.…”

A Complementary Biodiesel Blend from Soapnut Oil and Free Fatty Acids

“…According to the prediction of reaction rate kinetics, the biodiesel blend can be stored more 449 days. However, approximately 200 ppm and 150 ppm of PDA was required to guarantee a half year of storage, which is the current recommendation for biodiesel shelf life [24,25], based on EN 14,112 and EN 15,751, respectively. It was obvious that the further study is required to verify the validity of the two prediction models for biodiesel shelf life.…”