Update of Distillers Grains Displacement Ratios for Corn Ethanol Life-Cycle Analysis.

Abstract

Production of corn-based ethanol (either by wet milling or by dry milling) yields the following coproducts: distillers grains with solubles (DGS), corn gluten meal (CGM), corn gluten feed (CGF), and corn oil. Of these coproducts, all except corn oil can replace conventional animal feeds, such as corn, soybean meal, and urea. Displacement ratios of corn-ethanol coproducts including DGS, CGM, and CGF were last updated in 1998 at a workshop at Argonne National Laboratory on the basis of input from a group of experts on animal feeds, including Prof. Klopfenstein (University of Nebraska, Lincoln), Prof. Berger (University of Illinois, Urbana-Champaign), Mr. Madson (Rapheal Katzen International Associates, Inc.), and Prof. Trenkle (Iowa State University) (Wang 1999). Table 1 presents current dry milling coproduct displacement ratios being used in the GREET model. The current effort focuses on updating displacement ratios of dry milling corn-ethanol coproducts used in the animal feed industry. Because of the increased availability and use of these coproducts as animal feeds, more information is available on how these coproducts replace conventional animal feeds. To glean this information, it is also important to understand how industry selects feed. Because of the wide variety of available feeds, animal nutritionists use commercial software (such as Brill Formulation{trademark}) for feed formulation. The software recommends feed for the animal on the basis of the nutritional characteristics, availability, and price of various animal feeds, as well as on the nutritional requirements of the animal (Corn Refiners Association 2006). Therefore, feed formulation considers both the economic and the nutritional characteristics of feed products