Location: Bio-oils ResearchTitle: Mixed alkyl esters from cottonseed oil: Improved biodiesel properties and blends with ultra-low sulfur diesel fuel) Author
Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/17/2011
Publication Date: 1/3/2012
Citation: Joshi, H., Moser, B.R., Walker, T. 2012. Mixed alkyl esters from cottonseed oil: Improved biodiesel properties and blends with ultra-low sulfur diesel fuel. Journal of the American Oil Chemists' Society. 89(1):145-153. Interpretive Summary: This research reveals that the fuel properties of biodiesel can be improved by making a small change to how the fuel is made. Biodiesel suffers from poor cold flow properties vs. conventional petroleum-derived diesel fuel. In other words, biodiesel “gels” at higher temperatures than petrodiesel. The objective of this study was to improve the cold flow properties (CFP) of biodiesel by changing the composition of the fuel. Biodiesel is normally prepared by mixing methanol and vegetable oil in the presence of a catalyst. We used alcohols other than methanol to make biodiesel, thus changing its final composition. This modified biodiesel had better CFP than biodiesel prepared by the normal procedure. These results will be important to biodiesel producers, distributors, and end-users (customers) because insight was obtained on improving the CFP of biodiesel. 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: Transesterification of refined cottonseed oil was carried out with methanol, ethanol, 1-butanol, and various mixtures of these alcohols at constant volume ratio of alcohol to oil (1:2) using KOH (1 wt%) as catalyst to produce biodiesel. In the mixed alcohol transesterifications, the formation of methyl esters was faster than ethyl and butyl esters. Cottonseed oil-based biodiesel prepared from methanol to ethanol and butanol volume ratios of 1:1 or greater exhibited enhanced low temperature properties vs. neat methyl esters and were within the prescribed limits contained in the ASTM D6751 and EN 14214 biodiesel standards with respect to kinematic viscosity and acid value. Also examined was the influence of blending alkyl esters with ultra-low sulfur diesel (ULSD) fuel. All blends exhibited improved low temperature operability (CP, PP and CFPP) vs. unblended alkyl esters and significantly enhanced lubricity vs. unblended petrodiesel as well as properties within the specified ranges of the petrodiesel standards ASTM D975 and ASTM D7467. In summary, mixed alkyl esters prepared from cottonseed oil displayed improved fuel properties versus methyl esters alone.