VEGETABLE OIL-BASED FUELS, ADDITIVES AND COPRODUCTS
Location: Bio-oils Research Unit
Title: Biodiesel from Meadowfoam (Limnanthes alba L.) Seed Oil: Exceptional Oxidative Stability and Unusual Fatty Acid Composition
Submitted to: Energy and Environmental Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 23, 2009
Publication Date: January 28, 2010
Citation: Moser, B.R., Knothe, G.H., Cermak, S.C. 2010. Biodiesel from Meadowfoam (Limnanthes alba L.) Seed Oil: Exceptional Oxidative Stability and Unusual Fatty Acid Composition. Energy and Environmental Science. 3:318-327.
Interpretive Summary: This research reveals that meadowfoam oil is acceptable as an alternative feedstock for biodiesel production. The objective of this study was to produce biodiesel from meadowfoam oil and evaluate its fuel properties, taking into consideration important biodiesel fuel standards. Meadowfoam biodiesel fuel was exceptionally stable to unwanted oxidative degradation. This result is important because normally one of the technical disadvantages of biodiesel versus petroleum diesel fuel is poor oxidative stability. These results will be important to biodiesel producers, distributors and end-users (customers) because a new biodiesel fuel was described that exhibits favorable fuel properties. This research may ultimately improve market penetration, availability and public perception of domestically produced agricultural fuels, such as biodiesel, thus affording greater national independence from imported petroleum-based fuels.
Meadowfoam (Limnanthes alba L.) seed oil methyl esters (MFME), prepared by a standard transesterification procedure using methanol and sodium methoxide catalyst from refined meadowfoam oil (MFO), were evaluated as a potential biodiesel fuel. MFME contains the unusual 5(Z)-eicosenoate (64.2 wt %) and 5(Z),13(Z)-docosadienoate (18.9 wt %). The cetane number of MFME, 66.9, is among the highest ever reported for a biodiesel fuel. In addition, MFME exhibited exceptionally high oxidative stability of 41.5 h by the Rancimat method. Kinematic viscosity was determined as 6.18 mm2/s. The cloud, cold filter plugging and pour points of MFME were determined as -6, -9, and -10 deg C, respectively. Blending MFME with soybean oil methyl esters (SME) provided kinematic viscosity and oxidative stability within ranges specified in biodiesel fuel standards ASTM D6751 and EN 14214. Other properties such as acid value, free and total glycerol content, as well as sulfur and phosphorous contents, were below limits specified in ASTM D6751 and EN 14214. Also reported are lubricity, heat of combustion and Gardner color. For sake of comparison of some fuel properties, MFME was also prepared from crude meadowfoam oil. The most conspicuous difference in fuel properties was the even greater oxidative stability of 71.6 h by the Rancimat method of MFME from crude MFO. Addition of MFME (from refined MFO) to petrodiesel improved lubricity of ultra-low sulfur petrodiesel while not adversely affecting oxidative stability and low temperature operability. In summary, MFME has unusual fuel properties as a result of its unique fatty acid composition and appears to be a satisfactory blend component for SME and petrodiesel.