Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 2008
Publication Date: September 7, 2008
Citation: Isbell, T. 2008. Thlaspi arvense (Pennycress) as a biodiesel in a one year-two crop rotation with soybean [abstract]. Association for the Advancement of Industrial Crops Conference. p. 6. Technical Abstract: Increased demand for energy has generated renewed interest in the development of oilseed crops. The short term answer to biodiesel has always been soybean. Unfortunately, soybean oil has several shortcomings in its effort to supply the U.S. market. First, and foremost, is the fact that if all current soybean oil was converted to biodiesel, we could only supply 12% of the U.S. diesel demand. Established oilseed crops, such as canola, rapeseed, sunflower, and flax have high oil yields per acre and can meet some of the burden for fuel production. However, these oils are used extensively in food and the resulting balance between foods vs. fuel must be considered. New crops that can be grown in rotation with traditional crops, and off-season production and utilization of acreage not currently under cultivation, will also play a role in meeting these industrial needs. Pennycress has potential as a winter annual in rotation with soybean production throughout the Midwest. The objective of this study was to evaluate the physical properties of pennycress oil and its methyl esters for suitability as a biodiesel. Pennycress seeds were obtained from combine harvesting of wild strands using conventional combines. The seeds were cleaned by screening, aspiration and gravity table fractionation. Oil was recovered from whole seed by passing through a screw press and filtration. The oil was converted to methyl esters using a sodium methoxide catalyst in methanol. Pour point, cloud point, viscosity, flash point acid value, copper corrosion, and oxidative stability were determined on both the oil and the methyl esters using the appropriate ASTM method. The seed was found to contain 36% oil with the major fatty acid as erucic at 38.1%, and an iodine value of 115. Viscosity index (VI) of the methyl esters was 277, with a 40 deg C viscosity of 5.0 CST, and pour point and cloud points of -15 and -10 deg C, respectively. The starting oil had a VI of 222, with a 40 deg C viscosity of 39.1 CST, and pour point and cloud points of -18 and -10 deg C, respectively. As expected, the flash point of the methyl esters at 136 deg C was considerably less than the starting oil at 234 deg C. OSI of the oil at 100 deg C was 39 h and 54 h for methyl esters. The early harvest date of pennycress, compared to other winter annual oilseed crops, will make it suitable for a two-crop rotation with soybeans in most of the Midwestern U.S. In addition, the physical properties of the methyl esters indicate that continued development of the oil as a biodiesel is warranted.