News last update:6 Aug 2012

Flowability problems of DDGS

Dried distillers'grains with solubles (DDGS) can have some undesirable handling characteristics related to poor flowability under certain conditions. Reduced flowability and bridging of DDGS in bulk storage containers and transport trucks hampers their in feeding livestock.

So far the flow characteristics of DDGS have marginally been researched. In other products routinely flow enhancing product are added, such as for example calcium carbonate in soybean meal.

Research by the Swine research Group at the University of Minnesota, lead by Lee Johnston, professor and swine Extension specialist, designed a study to determine if the addition of selected flowability agents is effective in improving flowability of DDGS in practical commercial conditions.

The study was conducted at the BushMills Ethanol plant in Atwater, Minnesota. Four treatments were examined: a control that received no flowability agent; 5 pounds (2.25 kg) per ton of DMX-7 (Delst, Inc.); 2% calcium carbonate (ILC Resources); or 1.25% clinoptilolite zeolite (St. Cloud Mining).

Each of these flowability agents were mixed into lots of DDGS with either 9% or 12% moisture, resulting in a total of eight treatments.
Once the lots of DDGS were prepared, each one was loaded into a separate compartment of a commercial feed truck. The truck travelled about 250 km, sat idle for two days, and then travelled 250 km back to the ethanol plant. Upon returning to the ethanol plant, the time required to unload each compartment of the truck was recorded.

From these recordings it was found that drying DDGS to 9% moisture greatly improved flowability compared to 12% (620 kg/minute vs. 390 kg/min). None of the flowability agents improved the flow rate of the DDGS.
Johnston concludes that moisture level of DDGS plays a very important role in determining the flowability of the final product. Addition of the flowability agents at the levels they studied provided little evidence for improved flowability of DDGS.
An additional aspect of the study yet to be completed is to determine characteristics of DDGS that might predict poor flow rates before they create problems in commercial systems.

"By evaluating and determining the main factors involved with flowability of DDGS, we hope to be able to explain differences in flowability observed from different DDGS sources, and aid ethanol plants in improving the handling characteristics of DDGS produced," Johnston said.

Related link:
Dossier AllABout Bio Energy

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