The Effect of Natural and Synthetic Antioxidants on the Oxidative Stability of Biodiesel

Journal of the American Oil Chemists' Society - Tập 85 - Trang 373-382 - 2008
Haiying Tang1, Anfeng Wang1, Steven O. Salley1, K. Y. Simon Ng1
1Chemical Engineering and Materials Science, Wayne State University, Detroit, USA

Tóm tắt

A significant problem associated with the commercial acceptance of biodiesel is poor oxidative stability. This study investigates the effectiveness of various natural and synthetic antioxidants [α-tocopherol (α-T), butylated hydroxyanisole (BHA), butyl-4-methylphenol (BHT), tert-butylhydroquinone (TBHQ), 2, 5-di-tert-butyl-hydroquinone (DTBHQ), ionol BF200 (IB), propylgallate (PG), and pyrogallol (PY)] to improve the oxidative stability of soybean oil (SBO-), cottonseed oil (CSO-), poultry fat (PF-), and yellow grease (YG-) based biodiesel at the varying concentrations between 250 and 1,000 ppm. Results indicate that different types of biodiesel have different natural levels of oxidative stability, indicating that natural antioxidants play a significant role in determining oxidative stability. Moreover, PG, PY, TBHQ, BHA, BHT, DTBHQ, and IB can enhance the oxidative stability for these different types of biodiesel. Antioxidant activity increased with increasing concentration. The induction period of SBO-, CSO-, YG-, and distilled SBO-based biodiesel could be improved significantly with PY, PG and TBHQ, while PY, BHA, and BHT show the best results for PF-based biodiesel. This indicates that the effect of each antioxidant on biodiesel differs depending on different feedstock. Moreover, the effect of antioxidants on B20 and B100 was similar; suggesting that improving the oxidative stability of biodiesel can effectively increase that of biodiesel blends. The oxidative stability of untreated SBO-based biodiesel decreased with the increasing indoor and outdoor storage time, while the induction period values with adding TBHQ to SBO-based biodiesel remained constant for up to 9 months.

Tài liệu tham khảo

National Biodiesel Board Web site (2007) Estimated US biodiesel sales, http://www.biodiesel.org/pdf_files/fuelfactsheets/Biodiesel_Sales_Graph.pdf. (accessed Aug. 2007)

Tao Y (1995) Operation of a cummins N14 diesel on biodiesel: performance, emissions and durability. National Biodiesel Board, Ortech Report No. 95-E11-B004524

EN 14112 (2003) Determination of oxidation stability (accelerated oxidation test)

Alleman TL, McCormick RL, Deutch S (2007) 2006 B100 quality survey results, National Renewable Energy Laboratory, NREL/TP-540-41549

McCormick RL, Westbrook SR (2007) Empirical study of the stability of biodiesel and biodiesel blends. National Renewable Energy Laboratory, NREL/TP-540-41619

Prankl H, Lacoste F, MIttelbach M, Blassnegger J, Brehmer T, Frohlich A, Dufrenoy B, Fischer J (2003) Stability of biodiesel—used as a fuel for diesel engines and heating systems. BIOSTAB Project Results, contract number: QLK5-CT-2000-00533

ASTM D 6584-00 (2000) Determination of free and total glycerin in B-100 biodiesel methyl esters by gas chromatography, Philadelphia

ASTM D 97-96a (1996) Standard test method for pour point of petroleum products, Philadelphia

ASTM D 6371-05 (2005) Standard test method for cold filter plugging point of diesel and heating fuels, Philadelphia

Kinast JA (2003) Production of biodiesels from multiple feedstock’s and properties of biodiesels and biodiesel/diesel blend. National Renewable Energy Laboratory, NREL/SR-510-31460