Ethanol production by continuous fermentation–pervaporation: a preliminary economic analysis

Pervaporation can be utilized for recovery of ethanol from fermentation broths, thus suggesting a continuous fermentation process for fuel ethanol production. Based upon previously established laboratory performance data for pervaporation, a flux of 0.15 kg/m2/h and a selectivity of 10.3, process equipment was designed, sized, and costs estimated for the fermentation, pervaporation, distillation, and dehydration sections of a commercial-scale fuel ethanol plant. These costs were compared to those of a typical dry milling ethanol facility. For a baseline membrane cost of $200 m2, costs for the fermentation–pervaporation process were slightly higher. Sensitivity analyses on the pervaporation performance parameters indicated that with only minor improvement in either flux or selectivity, a process employing pervaporation for ethanol recovery from fermentation broths could be cost-effective.