Dry-Grind Process for Fuel Ethanol by Continuous Fermentation and Stripping

Conversion of a high-solids saccharified corn mash to ethanol by continuous fermentation and stripping was successfully demonstrated in a pilot plant consuming 25 kg of corn per day. A mathematical model based on previous pilot plant results accurately predicts the specific growth rate obtained from these latest results. This model was incorporated into a simulation of a complete dry-grind corn-to-ethanol plant, and the cost of ethanol production was compared with that of a conventional process. The results indicate a savings of $0.03 per gallon of ethanol produced by the stripping process. The savings with stripping result from the capacity to ferment a more concentrated corn mash so there is less water to remove downstream.