Corn Utilization and Technology Conference

June 2-4, 2014

Kun Xie, Congmu Zhang and Kurt Rosentrater Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA 50011

The authors thank Dr. Hui Wang and Alan Gaul for technical assistance; and thank you to Lincolnway Energy for providing DDGS.

Fractionation of Distillers Dried Grains with Solubles (DDGS) Through Gravity Separator Abstract

• Distillers Dried Grains with Solubles (DDGS) mainly contain

protein, oil, fiber, and ash. Fractionation process could

increase its economic value and broaden the utilization.

• The optimization of three parameters of a gravity separator

(side slope of the deck, eccentric shaft vibration, and air flow

rate), was conducted to separate DDGS. Nutrient analysis was

measured to determine the most effective parameter

combination for DDGS fractionation. This process was found

to be effective in getting substantial fractions enriched in

protein and oil.

DDGS Sieving

< 0.425 mm

0.425-2.000

mm

> 2.000 mm

Sieving

0.850-2.000

mm

0.425-0.850

mm

Material and Methods

• The DDGS we used for fractionation were collected from

Lincolnway Energy, LLC in Neveda, Iowa.

• DDGS were then stored in plastic tubes at room temperature

(23 ± 1oC).

• DDGS were firstly sieved into five size categories using sifter,

then three categories and raw DDGS were further separated

into four fractions using gravity separator.

Figure 1. Flowchart of Sieving

DDGS Gravity

Separation

Heavy

Mid-Heavy

Light

Mid-Light

Figure 2. Flowchart of Gravity Separation

Table 1. Parameter Design for Gravity Separation

Results

Near-Infrared Spectroscopy (NIR) tests showed satisfactory

separation on protein and oil.

Table 2. NIR Results of Different Categories Before Gravity Separation

• Gravity Separator: TKV25, (Forsberg Incorporated, Thief River

Falls, Minnesota, U.S.); 60-mesh (0.250 mm) steel deck, size of

2’x 3’ (0.6096m x 0.9144m)

• Airflow rates range from 0.7620 to 1.5240 m/s

• Each run lasted for three minutes

• Two replications

• Random order

Figure 3. Protein and Oil Percentage for Different Fractions After Gravity

Separation

Table 3. Two-way ANOVA for Components of DDGS Fractions

Conclusions

The most economic profit can be attained when using following

parameters:

• Eccentric shaft vibration: 420 rpm

• Deck side slope: 5o

• Airflow rate: 0.8890 m/s

• DDGS size category: 0.425-2.000 mm