Quantification of Physical and Chemical Properties, and Identification of Potentially Valuable Components from Fuel Ethanol Process Streams

Wider exploration of ethanol coproduct uses is necessary as the ethanol industry continues to face challenges. Currently, process streams such as thin stillage and condensed distillers solubles (CDS) are processed into distillers dried grains with solubles and used as animal feeds, but other higher value opportunities may exist. The objective of this study was to identify chemical components and quantify physical properties of CDS and thin stillage. Protein, organic acid, and sugar profiles were determined. Zein protein was identified, and glycerol was determined to have a concentration of 18.8 g/L in thin stillage and 63.2 g/L in CDS. Physical properties including density, thermal conductivity, thermal diffusivity, and rheological behaviors were also examined. Thermal conductivity of thin stillage and CDS was approximately 0.54 and 0.45 W/m°C, respectively. Quantification of the physical properties and identification of the chemical constituents pave the way for exploration of new value-added uses for thin stillage and CDS.