Separation of Fiber From Distillers Dried Grains With Solubles Using Sieving and Elutriation
"A process was developed to separate fiber from distillers dried grains with solubles (DDGS) in the dry grind corn process. Two products were obtained by separating fiber from DDGS: (1) enhanced DDGS with lower fiber, higher fat and higher protein contents and (2) fiber. This process was called the ""elusieve process""; two separation methods, sieving and elutriation (air flow), were used. DDGS samples were sieved into five sieve categories. The two smallest sieve categories comprised > 40% of the original DDGS weight and had lower fiber and higher protein and fat contents. An apparatus was designed to elutriate fiber from DDGS samples. Elutriation of the larger three sieve categories resulted in higher protein and fat contents and lower fiber contents in the fractions that settled at the bottom of the elutriation column. This process was beneficial in separating fiber from DDGS. Fiber in DDGS had higher particle density than nonfiber. Fiber was flat shaped while nonfiber was nearly spherical. Fiber particles were carried selectively at low air velocity despite their higher density because: (1) fiber particles in the sieve category have lower or comparable weight to smallest nonfiber particles due to their flatness and (2) flat shaped particles experience higher drag force than spherical shaped particles. For a dry grind plant processing corn at a rate of 1,020 metric tonnes/day (40,000 bu/day), capital investment was estimated to be $0.9 million and the payback period was 1.4 to 2.2 yr. Elutriation apparatus was scaled up (1:6) to process DDGS at higher input rates. Enhanced DDGS had higher phytosterol content than elusieve fiber. Elusieve fiber was suitable for production of corn fiber gum and ethanol. Elusieve process was beneficial in separating fiber from distillers dried grains (DDG) also."
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign