Technical and economic considerations for various recovery schemes in ethanol production by fermentation

Six alternative ethanol recovery processes were investigated from an economic and technical perspective. The processes were evaluated by use of the commercial simulation software Aspen HYSYS 2004.2 with an integrated fermentation model. The six alternatives included two variations of the flash fermentation process as well as various distillation configurations. Certain weaknesses and potential processing improvements were highlighted, and economic and technical targets were set for future comparisons. Distillation with two columns operating at different pressures and distillation with a vapor recompression system for heat recovery were found to be the best alternatives overall. However, from an energy standpoint, the modified flash fermentation process yielded the highest efficiency.