Location: Bio-oils Research Unit
Title: Preparation of fatty acid methyl esters from hazelnut, high-oleic peanut and walnut oils and evaluation as biodiesel Author
Submitted to: Fuel
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 2, 2011
Publication Date: August 23, 2011
Citation: Moser, B.R. 2012. Preparation of fatty acid methyl esters from hazelnut, high-oleic peanut and walnut oils and evaluation as biodiesel. Fuel. 92:231-238. Interpretive Summary: This research reveals that plant oils from common North American trees are acceptable as alternative feedstocks for biodiesel production. The objective of this study was to produce biodiesel from peanut, walnut and hazelnut oils and evaluate their fuel properties by taking into consideration important biodiesel fuel standards. These biodiesel fuels were also blended with petroleum diesel. Overall, the fuel properties of the biodiesel fuels and their blends with petrodiesel were comparable to that of soybean-based biodiesel and its blends, thus indicating the acceptability of peanut, hazelnut and walnut oil-based biodiesel fuels. 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.
Technical Abstract: Hazelnut, walnut and high-oleic peanut oils were converted into fatty acid methyl esters using catalytic sodium methoxide and evaluated as potential biodiesel fuels. These feedstocks were of interest due to their adaptability to marginal lands and their lipid production potentials (780-1780 L ha-1 yr-1). Oleic acid was the principle constituent identified in hazelnut (HME; 76.9%) and peanut (PME; 78.2%) oil methyl esters. Walnut oil methyl esters (WME) were comprised primarily of linoleic (60.7%), oleic (15.1%) and linolenic (12.8%) acids. PME exhibited excellent oxidative stability but poor cold flow properties due to its high content of monounsaturated and very-long chain fatty esters. WME provided a poor derived cetane number and oxidative stability as a result of its high percentage of polyunsaturated fatty esters. HME yielded a satisfactory balance between all fuel properties when compared against the biodiesel standards ASTM D6751 and EN 14214 due to its high content of monounsaturated fatty esters. Also explored were the properties of blends of HME, PME and WME in ultra-low sulfur (<15 ppm) diesel (ULSD) fuel and comparison to petrodiesel standards ASTM D975, D7467 and EN 590. With increasing the content of biodiesel, the oxidative stability, cold flow properties and energy content of ULSD was negatively affected, whereas lubricity was markedly improved. Kinematic viscosity, specific gravity and surface tension were impacted to a lesser extent by the addition of biodiesel to petrodiesel. In summary, HME, PME and WME appear to be suitable as biodiesel fuels based on fuel properties of the methyl esters and their blends with ULSD.