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Particle Segregation Within a Pile of Bulk Distillers Dried Grains with Solubles (DDGS) and Variability of Nutrient Content

¹Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN. ²Corresponding author. Phone: 765-494-1198. Fax: 765-496-1115. E-mail: ileleji@purdue.edu

Piling Dried Distillers's Grains with Solubles (DDGS) using gravity discharge is common in the corn-ethanol industry. This study investigated the occurrence of particle segregation within piles of DDGS formed by gravity discharge and subsequent spatial nutrient variability. Particle segregation tests were performed in a laboratory study where piles of DDGS were formed using samples collected from two fuel ethanol plants (an “old” and a “new” generation plant), and a plant study performed on piles of DDGS formed at the same two fuel ethanol plants. In both the laboratory and plant studies, the piles were formed by gravity-driven discharge and sampled at various categorized sections from the center of the pile to the periphery. Our results gave similar conclusions to a prior bench-scale study and confirmed that particle segregation does result in significant differences in particle size at the sampled locations of the pile. Particle size expressed as the geometric mean diameter (d_gw) increased from the core of the pile to the periphery. Of all the nutrient composition tested, only crude protein and moisture correlated with particle size. While the correlation of crude protein with particle size was not consistent and clearly discernible in all the piles sampled in both the bench-scale and plant studies, the correlation of particle size with moisture showed a strong positive correlation. Based on these findings, we recommend the development of a standard sampling protocol following good sampling practices for bulk granular solids.