Selected Additives Did Not Improve Flowability of DDGS in Commercial Systems

Abstract

An experiment was conducted at a commercial, dry-grind ethanol plant to determine if selected additives would improve flowability of dried distillers grains with solubles (DDGS). Main treatment effects were moisture content of DDGS (9 vs. 12% w.b.) and anti-caking agent (ACA). The ACA treatments were: No additive (Control); a moisture migration control agent at 2.5 kg/metric ton (DMX-7); calcium carbonate at 2% w.b. (Calcium carbonate); or a clinoptilolite zeolite at 1.25% w.b. (Zeolite). The ACA were added at the desired level to about 2,275 kg of DDGS using a vertical-screw feed mixer. Batches of DDGS were weighed and loaded into one of eight compartments in an auger-equipped feed truck. After loading, the truck traveled 250 km, sat motionless for at least 60 h, and traveled 250 km back to the ethanol plant. Time required to unload each compartment was recorded. There were no significant interactions between moisture level and ACA for any response criteria. Mean moisture levels were 9% and 11.6% for low and high moisture treatments. Flow rate of DDGS at unloading was higher (P < 0.01) for the 9% compared with 12% moisture level (620 vs. 390 kg/min). Flow rates of DDGS at unloading were: 509 (Control), 441 (DMX-7), 512 (Calcium carbonate), and 558 (Zeolite) kg/min. None of the ACA created flow rates that differed significantly from Control. In conclusion, increasing moisture content from 9% to 11.6% clearly decreased flowability of DDGS. The ACA used in this experiment at the selected concentrations did not improve flowability of DDGS.