Submitted to: BioEnergy Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/16/2011
Publication Date: 5/7/2012
Citation: Moser, B.R., Vaughn, S.F. 2012. Biodiesel from corn distillers dried grains with solubles: Preparation, evaluation and properties. BioEnergy Research. 5:439-449.
Interpretive Summary: This research reveals that a co-product of ethanol production can be used as a low-cost feedstock for the production of biodiesel. One of the primary disadvantages of biodiesel relative to petroleum diesel is high cost, which is primarily caused by feedstock acquisition. Thus, identification and use of low-cost feedstocks has strong potential to dramatically improve the process economics and availability of biodiesel. The objective of this study was to produce biodiesel from corn distillers’ grains with solubles and evaluate fuel properties taking into consideration important biodiesel fuel standards. These biodiesel fuels were also blended with petroleum diesel. Overall, the fuel properties of the biodiesel fuels and their blends with petrodiesel were comparable to that of soybean-based biodiesel and its blends, thus indicating the acceptability of biodiesel prepared from corn distillers’ grains with solubles. These results will be important to biodiesel producers, distributors and end-users (customers) along with ethanol producers 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: Corn distillers’ dried grains with solubles (DDGS) is a co-product of dry-grind ethanol fermentation and represents a low-cost feedstock with potential to improve process economics and logistics of biodiesel manufacture through integration of biodiesel and ethanol production. Oil extracted from DDGS was converted into distillers’ grains methyl (DGME) and ethyl (DGEE) esters. Pretreatment using a dual catalytic sulfuric acid/synthetic magnesium silicate methodology was effective at lowering the acid value of the crude oil from 27.15 to less than 0.30 mg KOH g-1, thus rendering it amenable to homogenous base-catalyzed transesterification. Measurement of several fuel properties and comparison to analogous esters prepared from refined corn oil (RCME and RCEE) revealed that the cold flow properties and oxidative stability of DGME and DGEE were deficient relative to RCME and RCEE. In addition, in the absence of antioxidants, DGME and DGEE did not meet the oxidative stability specifications of ASTM D6751 and EN 14214. The cetane number of DGEE was below the minimum limit specified in EN 14214. DGEE exhibited more favorable cold flow properties, iodine value and energy content than DGME. Blends (B5 and B20) in petroleum diesel fuel were also evaluated, and it was determined that antioxidants and cetane enhancers would be required to meet the specifications of the U.S. and European diesel fuel standards. Other fuel properties of the petrodiesel blends were largely neutral with respect to alkyl ester type and conformed to the limits specified in the respective standards.