Operating Characteristics of a High-Efficiency Pilot Scale Corn Distillers Grains Dryer

Abstract

The rapidly expanding U.S. corn ethanol industry produces huge quantities of wet distillers grains and about 70% of this material is dried to 10% moisture. Drying this material requires about one-third of the energy used to operate a dry-grind corn ethanol plant. Tri-Phase Drying Technologies of Norwalk, Iowa has developed a rotary drum dryer which reclaims energy from the exhaust air stream. The objective of this research was to determine the energy requirement of the Tri-Phase dryer by pilot scale drying tests with wet distillers grains. Multiple tests of the pilot-scale dryer showed an energy input requirement of about 2890 kJ/kg (846 Btu/lb) of water removed when drying wet distillers grains from about 28% to 24% moisture. This is less than half the energy usually required for a drum dryer or a grain dryer. Use of this dryer design, scaled up to dry distillers grains at ethanol plants, has the potential for large energy savings for the corn ethanol industry.