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National United University is a public university in Taiwan. Wikipedia.


Refined 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 lipid production potentials (780-1780 L ha -1 yr -1) and suitability for marginal lands. Methyl oleate was the principal constituent identified in hazelnut (HME; 76.9%) and peanut (PME; 78.2%) oil methyl esters. Walnut oil methyl esters (WME) were comprised primarily of methyl esters of linoleic (60.7%), oleic (15.1%) and linolenic (12.8%) acids. PME exhibited excellent oxidative stability (IP 21.1 h; EN 14112) but poor cold flow properties (CP 17.8 °C) due to its comparatively high content of very-long chain fatty esters. WME provided low derived cetane number and oxidative stability (IP 2.9 h) data as a result of its high percentage of polyunsaturated fatty esters. HME yielded a satisfactory balance between all fuel properties when compared to 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 content of biodiesel, the oxidative stability, cold flow properties and calorific value of ULSD was negatively affected, whereas lubricity was markedly improved. Kinematic viscosity, specific gravity and surface tension were impacted to lesser extents by addition of biodiesel to ULSD. In summary, HME, PME and WME are suitable based on their fuel properties as biodiesel fuels and blend components in ULSD. © 2011 Elsevier Ltd. All rights reserved. Source


Fatty acid methyl esters prepared from canola, palm, soybean, and sunflower oils by homogenous base-catalyzed methanolysis were stored for 12 months at three constant temperatures (- 15, 22, and 40 °C) and properties such as oxidative stability, acid value, kinematic viscosity, low temperature operability, and iodine value were periodically measured. Oxidative stability was significantly reduced upon extended storage and acid value as well as kinematic viscosity were increased by only small increments, with these effects more pronounced at elevated temperatures. Iodine value and low temperature operability were essentially unaffected by extended storage. Based on these findings, it is not recommended that acid value or kinematic viscosity be used as indicators of storage stability of biodiesel, nor is it recommended that iodine value be used as a predictor of oxidative stability or indicator of oxidative degradation. © 2010. Source


Knothe G.,National United University
Fuel | Year: 2014

The cetane number (CN), being related to ignition and combustion behavior, is a prime indicator of the quality of diesel fuels, including those derived from renewable resources such as biodiesel. While many effects of compound structure are known or have been postulated, experimental data have not always been available for the various ester components of biodiesel and a comprehensive evaluation including some structural features not yet experimentally investigated such as double bond configuration and position is lacking. In this work, existing CN data of fatty esters are complemented by studying C18 esters with differing double bond positions and double bond configurations. For the first time, CNs, determined as derived cetane number (DCNs), of neat trans fatty acid methyl esters, methyl elaidate (methyl 9(E)-octadecenoate) and methyl linolelaidate (methyl 9(E),12(E)-octadecenoate), were determined as were the CNs of the C18:1 positional isomers methyl petroselinate (methyl 6(Z)-octadecenoate) and methyl asclepate (methyl 11(Z)-octadecenoate). The CNs of the positional and geometric isomers of methyl oleate are close to the CN of methyl oleate. These data are compared to other previously determined CN data. Furthermore, the applicability of CN data is evaluated using an extensive collection of CN determinations for methyl oleate as "standard" fatty acid (methyl) ester. The average CN value for methyl oleate is in the range of 56-58 with a CN of 57 suggested for calculating purposes. Similarly, uncertainty ranges could be established for CNs of other fatty materials. The data are also useful for predicting CNs of compounds for which CNs are not readily available or easily determinable. Source


Knothe G.,National United University
Progress in Energy and Combustion Science | Year: 2010

The search for alternatives to petroleum-based fuels has led to the development of fuels from various sources, including renewable feedstocks such as fats and oils. Several types of fuels can be derived from these triacylglycerol-containing feedstocks. One of them is biodiesel, which is defined as the mono-alkyl esters of vegetable oils or animal fats. Biodiesel is produced by transesterifying the oil or fat with an alcohol such as methanol under mild conditions in the presence of a base catalyst. Another kind of product that can be obtained from lipid feedstocks is a fuel whose composition simulates that of petroleum-derived diesel fuel. This kind of fuel, probably best termed "renewable diesel", is produced from the fat or oil by a hydrodeoxygenation reaction at elevated temperature and pressure in the presence of a catalyst. This article discusses in a general and comparative fashion aspects such as fuel production and energy balance, fuel properties, environmental effects including exhaust emissions and co-products. Among the questions that are addressed are if these fuels compete with or complement each other and what the effect of production scale may be. Source


Biodiesel, one of the most prominent renewable alternative fuels, can be derived from a variety of sources including vegetable oils, animal fats and used cooking oils, as well as alternative sources such as algae. While issues such as land-use change, food vs. fuel, feedstock availability, and production potential have influenced the search for the "best" feedstocks, an issue that will ultimately determine the usability of any biodiesel fuel is that of fuel properties. Issues such as cold flow and oxidative stability have been problematic for biodiesel. The fatty acid profile of a biodiesel fuel is largely identical to that of the feedstock and significantly influences these properties. This article compares biodiesel derived from vegetable oils and biodiesel obtained from algae in light of fuel properties. While the properties of biodiesel fuels derived from vegetable oils are well-known, the properties of biodiesel obtained from algal oils have usually not been reported. The fatty acid profiles of many algal oils possess high amounts of saturated and polyunsaturated fatty acids. Thus, biodiesel fuels derived from algae in many cases likely possess poor fuel properties, i.e., both poor cold flow and low oxidative stability simultaneously. This observation shows that production potential alone does not suffice to judge the suitability of a feedstock for biodiesel use. This article also summarizes how the fuel properties of biodiesel can be improved through modification of the fatty ester content. Algal oils for biodiesel production are probably best produced under tightly controlled conditions since the fatty acid profile of algal oils is very susceptible to changes in these conditions. Algal oils likely yielding biodiesel with the least problematic properties as determined by reported fatty acid profiles are discussed. This journal is © The Royal Society of Chemistry. Source

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