Study: Fractionation can lead to improved profits

By Matt Thompson | November 15, 2019

While it’s not a new concept for the ethanol industry, a recently published study reveals that fractionation at corn ethanol plants can lead to improved profits.

The study, from the University of Illinois, addresses the quality of distillers dried grain with solubles (DDGS) and corn oil produced at ethanol plants. “One problem with the process is that the coproducts that you get, which are DDGS and corn oil, have a relatively low market value, and these coproducts also play a part in offsetting the costs for ethanol,” said Chinmay Kurambhatti, the study’s lead author. “To tackle these problems, if you’re able to fractionate corn, or separate fiber and germ, prior to fermentation, then you can get coproducts with a higher value and that can improve the profitability of the plant.”

Vijay Singh, who is the study’s corresponding author, said that several methods of fractionation were studied, including both wet and dry fractionation. “We took all the different wet fractionation and dry fractionation processes together and then compared them using the same assumptions to find out which one would be the best process,” Singh said. The best results, he said, came from wet fractionation techniques that take place prior to fermentation. “We feel that you get much higher and better value of your coproducts if you do that fractionation prior to the dry grind process, not inside the dry grind process,” Singh said.

The reason, he said, is that with wet fractionation, the corn’s individual components are more cleanly separated. However, this requires using water and a large capital expense. Dry fractionation is cheaper in terms of capital cost, but “the separation is not clean, and some of the nutrients that are needed in the fermentation process get removed with the coproduct. You suffer with low rates of fermentation, lower ethanol concentrations,” Singh said. The goal of his research, he said, is to improve dry fractionation techniques to achieve results like those achieved with wet fractionation.

Additional benefits of fractionation included the ability to introduce more feedstock into fermenters, which increases the amount of ethanol produced. “Because you’re making more concentrated ethanol at the back end, you require less energy to dehydrate that ethanol,” Singh said.

In addition, removal of the corn fiber at the beginning of the production process yields itself to converting that fiber to cellulosic ethanol. Singh said. “That is one of the things that these technologies do, is that they give us a very clean stream of fiber coming off, which then we can take and convert that to cellulosic ethanol and make even more profit from those D3 RINs, [renewable identification numbers]” he said.