Biodiesel Fuel Quality of Canola Feedstock Grown on Saline Land

Abstract

The increased demand for biodiesel feedstock encourages producers to expand areas seeded to oilseed crops. Vegetable oil from canola-grade feedstock ranks among the best in the production of fatty acid methyl esters (FAME or biodiesel). FAME produced from canola-quality oilseed grown on salt-affected lands offer new opportunities for increased production and can counter fuel-versus-food concerns, provided that the biodiesel product meets quality standards. The American Society for Testing and Materials (ASTM) has set the North American fuel quality standards (D6751) for 100% biodiesel (B100) to be blended with petrodiesel fuel. Canola-quality feedstock yields oil low in free fatty acids, i.e., acids that are not bonded to parent oil molecules. These free acids may negatively affect diesel engine components, especially at biodiesel oil blends greater than 20%. In addition, solid and dissolved impurities, alkali/alkaline earth metals, and oxidation stability are of concern to fuel injection equipment manufacturers. Ultimately, purity, composition, and biodiesel utility depend on the quality of the feedstock supplied. Transesterification and washing to produce biodiesel can improve purity, but these processes normally do not alter fatty acid composition. Contaminants in biodiesel fuel may include water, sediment, S, P, K, Na, Ca, Mg, carbon residue, and various other constituents in the fuel's sulfated ash. Canterra 1818 canola feedstock grown on negligibly, slightly, moderately, and severely salinized soil was crushed and tested for biodiesel fuel quality. All samples yielded biofuel within the ASTM specifications except for free glycerol in the negligibly saline sample.