Valorizing Distillers' Grains to Improve Corn Ethanol Profitability and Sustainability.

摘要

This study is dedicated to the research of producing additional value-added products from a corn ethanol biorefinery system to improve profitability and sustainability, with an emphasis on finding additional value in the hemicellulosic components of distillers' grains (DG), a corn ethanol byproduct, for potential products or utilizations as furfural, edible films, paper coatings and emulsifying agents. The DG's hemicelluloses were either extracted as monomeric sugars by dilute acid at 140--160 °C, or in their polymeric forms by alkaline solutions at 25--75 °C. The pentoses of the mono sugars from the acidic extraction were further dehydrated at 160--180 °C to produce furfural; whereas the polymeric hemicelluloses from the alkaline extraction were evaluated for their potential utilizations as films, paper coatings and emulsifying agents. The DG residues after acid hydrolysis or alkaline extraction were also evaluated for their animal feed qualities to maximize products produced and thus the economics of the process. This was further developed with created economic models that were optimized by maximizing the furfural or polymeric hemicelluloses as well as the extraction residue yields and minimizing the energy input. Thus, by analyzing the economic model, the DG valorizing processes were guided towards the direction with maximum profitability and sustainability.;To further enhance their utility, the polymeric hemicelluloses from DG were cross-linked by glutaraldehyde in dilute acid solution to improve their film and paper coating mechanical and physical properties, or were acylated by succinic anhydride in dilute alkaline solution to improve their emulsifying properties. The avoidance of using organic solvents during the modifications was a consideration for the economy, environment and product toxicity.