ARS | Publication request: Fuel properties of biodiesel from alternative feedstocks

Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: December 20, 2012
Publication Date: N/A

Technical Abstract: Defined as monoalkyl esters of long-chain fatty acids prepared from plant oils, animal fats, or other lipids, advantages of biodiesel over conventional petroleum diesel fuel include derivation from renewable and domestic feedstocks, superior lubricity and biodegradability, higher cetane number and flash point, non-toxic, negligible sulfur and aromatics content, and strongly positive energy balance. Among the principal disadvantages of biodiesel are lower oxidative and storage stability, inferior cold flow properties, high feedstock cost, and limited availability. Refined commodity oils with competing food applications such as canola or soybean account for more than 80% of the cost to commercially produce biodiesel. Therefore, the fuel properties of biodiesel prepared from several promising low-cost alternative sources were determined and compared to the biodiesel fuel standards ASTM D6751 and EN 14214. The feedstocks investigated in the current study included brown mustard (Brassica juncea), camelina (Camelina sativa), coriander (Coriandrum sativum), corn distillers’ dried grains, field pennycress (Thlaspi arvense), Osage orange (Maclura pomifera), and seashore mallow (Kosteletzkya pentacarpos). Biodiesel (fatty acid methyl esters) was prepared from hexane-extracted lipids via homogeneous, alkaline-catalyzed (sodium methoxide) transesterification following mineral acid-catalyzed (sulfuric acid) pretreatment (if necessary). Spanning a wide range of fatty acid profiles, agronomic potentials, and geographic distributions, the fuel properties of biodiesel prepared from these feedstocks were primarily influenced by fatty ester composition. Those enriched in polyunsaturated fatty esters (camelina, distillers’ grains, osage, seashore mallow) generally exhibited low oxidative stabilities and cetane numbers, whereas fuels with longer-chain (C20+) methyl esters (brown mustard, field pennycress) tended to provide high kinematic viscosities but excellent cetane numbers. Coriander-based biodiesel, which was enriched in the monounsaturated fatty ester methyl petroselinate, provided the most favorable balance of fuel properties, as it conformed to the specifications of the biodiesel standards without the need for performance-enhancing additives.