Degree Type


Date of Award


Degree Name

Master of Science


Agricultural and Biosystems Engineering


Agricultural and Biosystems Engineering

First Advisor

Kurt A. Rosentrater


Along with the increasing population, the lack of food and energy have become major global issues in 21 century. Bioethanol is now one of the most popular renewable energy sources and is mostly produced by corn in the US. The corn-based ethanol production has grown rapidly over the past two decades. The increasing of corn ethanol production also created a huge amount of by-product like DDGS, which commonly used as animal feed and make the whole industry even more profitable. However, the low bulk density and poor flowability inhibit the value of DDGS. The DDGS low bulk density and low flowability could be improved by pelleting process. Pellet quality is the key aspect of this project. To obtain a high yield of corn ethanol and high quality DDGS the quality of the ingredients is very important. There are many things can affect the overall corn quality from planting to storage. The drying process is a vital step to maintaining corn quality and extent the corn storage life. Our study was conducted to analysis the resultant DDGS pellet quality and evaluate a prototype low-temperature grain drying system.

The pelleting studies in this thesis were focused on analysis the resultant pellet quality by using 100% corn-based DDGS. The pelleting process was operated with three different DDGS moisture content and three different dies. The results showed that by using pilot-scale pellet mill, the bulk density can be increased and the flowability of DDGS could be improved by pelleting process.

The grain drying project talks about an experiment of measure the power consumption and moisture removal efficiency of a prototype low temperature grain drying system. The data were collected through two replications of the drying process. The drying results indicated that the system had high efficiency and had no negative effect on germination performance.

The TEA and LCA study were conducted to understand both environmental and economic impacts of an on-farm low-temperature grain drying system. Three scales of this drying system were analyzed in this study. The result showed that the unit drying cost decreased as the drying capacity expanded and the lowest unit drying cost was 0.46 USD per bushel of corn.

In conclusion, the pelleting process could be a valid way to improve the low bulk density and poor flowability of DDGS. The low temperature closed-cycle grain drying system was more efficient than other commonly used high temperature grain dryer and maintain the grain quality.


Copyright Owner

Mingjun Ma



File Format


File Size

98 pages