Eeconomic evaluation of alternative ethanol fermentation processes.

Eleven alternative fermentation schemes for ethanol production are compared. Conventional batch, continuous, cell recycle, and immobilized cell processes, as well as membrane, extraction, and vacuum processes which remove ethanol from the broth selectively as it is produced, are considered. The processes are compared on identical bases using a consistent model for the yeast metabolism. Both molasses and cellulose hydrolyzate are considered as feeds. Optimized ethanol plants, including feed preparation, fermentation, and product recovery sections are designed and total costs are projected.