Co-Production of Chemical and Energy Products from Distillers Grains using Supercritical Fluid Extraction and Thermochemical Conversion Technologies

Dry-grind technology has become the dominant method for ethanol production. During drygrind ethanol production, roughly one-third of the dry grain mass resides in the dried distillers grains with solubles (DDGS) as by-products (i.e., ∼0.8 kg/L ethanol). The energy content residing in the 0.8 kg DDGS is about 20 MJ, compared to the consumption of 1 MJ electricity and 10 MJ thermal energy for production of each liter of ethanol. A sequential supercritical fluid process with solvents including carbon dioxide, water and ethanol was used to recover high-value chemicals from DDGS. Thermochemical conversion methods were used to convert the DDGS residue after extraction to gaseous and liquid fuels