Preparation and fuel properties of field pennycress (Thlaspi arvense) seed oil ethyl esters and blends with ultra-low sulfur diesel fuel

Authors: Moser, Bryan; Evangelista, Roque; Isbell, Terry

Submitted to: Energy and Fuels
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/3/2015
Publication Date: 12/4/2015
Publication URL: http://handle.nal.usda.gov/10113/62384
Citation: Moser, B.R., Evangelista, R.L., Isbell, T.A. 2016. Preparation and fuel properties of field pennycress (Thlaspi arvense) seed oil ethyl esters and blends with ultra-low sulfur diesel fuel. Energy and Fuels. 30:473-479.

Interpretive Summary: This research reveals that field pennycress (Thlaspi arvense) seed oil is acceptable as an alternative non-food feedstock for biodiesel production. As a result of the current debates about fuel versus food issues, alternative, low-cost, non-food feedstocks for biodiesel production are an important area of current research. One of the objectives of this study was to produce biodiesel from field pennycress seed oil and evaluate its fuel properties, taking into consideration important biodiesel fuel standards. Field pennycress-biodiesel has excellent low temperature properties and cetane number as well as acceptable oxidative stability and viscosity when compared to the American biodiesel standard (ASTM D6751). Another objective was to determine the influence of blending field pennycress-derived biodiesel with traditional petroleum diesel fuel. The results indicated that the resulting blends met all requirements of the American petrodiesel standards (ASTM D975 and D7467). Blends of biodiesel with petrodiesel are important to study because the majority of biodiesel that ultimately enters the marketplace will do so as blends with petrodiesel. It is thus imperative to understand the influence of blending biodiesel with petrodiesel on fuel properties and performance. These results will be important to biodiesel producers, distributors, and end-users (customers) as well as petroleum companies and manufacturers of diesel engines 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: Field pennycress (Thlaspi arvense L.) is a widely distributed winter annual with high seed oil content (36%) and is suitable as an off-season rotational crop in the Midwestern U.S. Erucic [(13Z)-docosenoic] acid (36.2%) is the most abundant constituent in the oil, with unsaturated and very long chain (20+ carbons) fatty acids comprising most of the remaining content. In a previous study, we described field pennycress seed oil methyl esters (FPMEs). Here, we report field pennycress seed oil ethyl esters (FPEEs) along with the properties of blends of FPMEs and FPEEs (B2-B20) in petrodiesel. These results are compared to American and European biodiesel and petrodiesel fuel standards. FPEE were characterized by excellent low temperature properties (cloud point -15 deg C), high cetane number (61.4), high kinematic viscosity (5.65 mm2/s), and low oxidative stability (induction period of 4.6 h). Both kinematic viscosity and oxidative stability did not meet EN 14214 limits but were within the ranges prescribed in ASTM D6751. With regard to blends, highly linear correlations (R2 = 0.99) were noted between blend ratio and density, energy content, kinematic viscosity, moisture content, and specific gravity. The acid value, sulfur content, and surface tension were essentially unaffected by the blend ratio. Oxidative stability was negatively affected by a higher biodiesel content, which is typical for blends. Cold flow properties were minimally impacted by the blend ratio, thus representing a significant advantage of FPMEs and FPEEs over other biodiesel fuels. Both FPMEs and FPEEs were excellent lubricity enhancers, becauss even small amounts (B2) markedly improved the lubricity of petrodiesel. Where applicable, fuel properties of the blends were within the limits prescribed in the petrodiesel standards.