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ARS Home » Plains Area » Brookings, South Dakota » Integrated Cropping Systems Research » Research » Publications at this Location » Publication #212359
Title: Flow Properties of DDGS with Varying Soluble and Moisture Contents Using Jenike Shear Testing

Author
item GANESAN, V - SOUTH DAKOTA STATE UNIV
item MUTHUKUMARAPPAN, K - SOUTH DAKOTA STATE UNIV
item Rosentrater, Kurt

Submitted to: Journal of Powder Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/8/2008
Publication Date: 2/16/2008
Citation: Ganesan, V., Muthukumarappan, K., Rosentrater, K.A. 2008. Flow Properties of DDGS with Varying Soluble and Moisture Contents Using Jenike Shear Testing. Journal of Powder Technology. DOI 10.1016/j.powtec.2008.02.003.

Interpretive Summary: Distillers dried grains with solubles (DDGS), the primary coproduct of the fuel ethanol industry, are an excellent source of nutrients for livestock rations. With the growth of the US ethanol industry in the past several years, growing quantities of distillers grains are being generated. Flowability of DDGS is often problematic due to caking and bridging during storage and transport. In our previous studies, Carr Indeces were used to quantify they physical and flow properties of DDGS. The objective of this study was to extend that work and measure the flow properties (cohesion, effective angle of friction, internal angle of friction, yield locus, flow function, major consolidating stress, and unconfined yield strength) of DDGS using the Jenike shear tester. To provide a broad range of applicability, this study investigated the influence of four soluble levels (10, 15, 20, and 25% db) and five moisture contents (10, 15, 20, 25, and 30% db). With an increase in soluble levels, flow function curves for DDGS shift in an anticlockwise direction towards the shear stress ('c) axis, which indicates poorer flow. Depending on the soluble level, above certain moisture contents, moisture can actually act as a partial lubricant, easing the flow of the DDGS. Also, with higher solubles and moisture levels, the compressibility of DDGS was found to increase. Across all soluble and moisture levels, however, the DDGS was classified as a cohesive material, and it is likely to produce flowability problems.

Technical Abstract: Distillers dried grains with solubles (DDGS) are an excellent source of energy, minerals, and bypass protein for ruminants and are used in monogastric rations as well. With the remarkable growth of the US fuel ethanol industry in the past decade, large quantities of distillers grains are now being produced. Flow of DDGS is often restricted by caking and bridging during its storage and transportation. In our previous works, the Carr powder tester was used to measure various flow properties of DDGS. The objective of this study was to measure the flow properties (cohesion, effective angle of friction, internal angle of friction, yield locus, flow function, major consolidating stress, and unconfined yield strength) of DDGS using the Jenike shear tester. This work investigated the influence of four levels of solubles (10, 15, 20, and 25% db) and five levels of moisture content (10, 15, 20, 25, and 30% db) on the resulting flow properties of DDGS. With an increase in soluble levels, the flow function curves of DDGS shift in an anticlockwise direction towards the shear stress ('c) axis. Depending on the soluble level, above certain moisture contents, the moisture actually began acting as a lubricant, easing the flow of the DDGS. Also, with higher solubles and moisture levels, the compressibility of DDGS was found to increase. Overall, the DDGS was classified as a cohesive material, and it is likely to produce cohesive arching problems.