Thin stillage, potential for valuable biobased products

By Katie Fletcher | August 06, 2014

The 2014 American Coalition for Ethanol conference included a discussion of research efforts aimed at making ethanol plants more profitable. Ken Valentas, professor at the University of Minnesota, and Joseph Molde, a student, have been conducting research on recovering valuable biobased products from thin stillage in corn ethanol plants. The research hasthe potential to significantly improve cash flow at corn ethanol plants. “There is an opportunity to stabilize the profits in corn ethanol, and put a buffer in there when corn prices vary,” Valentas said. “Thin stillage can potentially be converted to higher value products than DDGs to improve cash flow and stabilize profitability.”

Valentas shared a proprietary thermochemical process called hydrothermal carbonization (HTC) that produces hydrochars, which can be modified in several different ways by post treatment to result in carbon-rich products that have utility as absorbents, polymer additives and carbon nanoparticle replacements in super capacitors. “The objective is to take biomass and increase the carbon to oxygen ratio so it’s a better ratio,” Valentas said.

Other products that can be sourced from thin stillage are phosphorus, a valuable component to fertilizer, and fatty acids, which can be converted to jet fuel or biodiesel. “Phosphorus and fatty acid pays the bill and the profit is in the hydrochar—this has got a lot of potential,” Valentas said.