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. Keywords. Flowability, DDGS, Angle of repose, Anti-caking agents he Energy Policy Act passed by the U. S. Congress in 2005 mandates that 7.5 billion gallons of renewable fuels be included in gasoline sold in the United States by the year 2012 (U.S. Environmental Protection Agency, 2008). This mandate has supported the rapid expansion of ethanol production in the United States. Ethanol production in 2008 is projected to be nearly 8 billion gallons (Renewable Fuels Association, 2008). Dried distillers grains with solubles (DDGS) is an important co-product of ethanol production. About 7.2 kg of DDGS and 10.6 L of ethanol are produced from 25 kg of corn. Consequently, large quantities of DDGS are available for feeding livestock domestically and internationally. DDGS has many positive attributes for the feeding of livestock (University of Minnesota, 2008). Unfortunately, DDGS can have some undesirable handling characteristics related to poor flowability under certain conditions (Agricultural Utilization Research Institute (AURI) and Minn. Corn Growers Assoc., 2005; Bhadra et al., 2008). Reduced flowability, or the potential for reduced flowability of DDGS prevents the routine use of railcars for transport. Reduced flowability and bridging of DDGS in bulk storage containers and transport vehicles limits the use of DDGS for feeding

Influence of Storage Bin Design and Feed Characteristics on Flowability of Pig Diets Containing Maize Distillers Dried Grains with Solubles

“…Replicate (summer or fall) was included as a random effect. Previous research reported from our laboratory indicated that flowability of feed was reduced substantially once moisture content exceeded 10% (Johnston et al, 2009) and feed is hygroscopic and can absorb water from the surrounding environment. Thus, moisture content of the feed corresponding with the day of feed flow determinations was used as a covariate in all statistical analyses.…”

“…The number of taps required to establish feed flow was recorded. In addition, a subjective flowability score (1 = free flowing, 10 = completely bridged) was assigned to the feed flow as described by Johnston et al (2009). Tapping and subjective flowability scores were performed by the same individual throughout the trial.…”

“…These samples were used to determine moisture content of the feed and a field test of the poured and drained angles of repose using a modified Hele-Shaw cell as described by McGlinchey (2005) and Johnston et al (2009; fig. 2).…”

“…Despite this long list of factors, very few of these can be controlled in commercial pork production systems. Maize-dried distillers grains with solubles (DDGS) are notorious for poor flowability under conditions commonly experienced in commercial pork production systems (Bhadra et al, 2009;Johnston et al, 2009). Anecdotal reports from pork producers are consistent and indicate that inclusion of high levels of maize DDGS (30% or greater on an as-fed basis) in swine diets significantly reduces flowability of feed.…”

“…However, during times of high maize prices, pork producers often use high levels of maize DDGS in diets to reduce feed costs, regardless of its negative effect on flowability of the diet. One might expect that the use of anti-caking agents could provide a simple solution to poor flowability, but previous research with DDGS suggests common anti-caking agents are not effective in improving flow rate (Ganesan et al, 2008a;Johnston et al, 2009).…”