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Highlights • Biphasic acetone-butanol-ethanol after in situ gas stripping was purified by distillation. • Four distillation sequences were investigated and optimized. • Techno-economic analysis was carried out to choose favorable sequences. • Energy requirement of distillation was decreased by 25.8%. • Total annual cost of distillation was decreased by 17.4%. Abstract Distillation processes for separation of biphasic ABE solution from in situ gas stripping were developed. The distillation sequences were investigated and optimized. Results proved the energy requirement of distillation was effectively reduced when feeding the biphasic ABE mixture. After techno-economic analysis, a superior scenario that started with a decanter followed with side-by-side sequences for separation acetone and ethanol was selected. Compared with the conventional processes that detractively concentrate the biphasic ABE mixture, energy requirement and total annual cost (TAC) of the novel distillation process were decreased by 25.8% and 17.4%, respectively. $ 4102.98 K per year of TAC was estimated in a case with a capacity of 30 K tons of butanol per year. [ABSTRACT FROM AUTHOR]

In this work, the acetone-butanol-ethanol (ABE) fermentation was upgraded in order to improve its economy. Fed-batch fermentation was integrated with two-stage gas stripping-pervaporation unit. The permeated ABE condensate was used as substrate for oleates production. Candida sp. 99–125 cells, being rich in lipase activity, were used as full-cell catalyst. Different ABE feeding strategies in the esterification process were compared. As results, 10.1%, 68.6% and 72.5% of butyl oleate were obtained in the one-step added scenario, the stepwise-added scenario, and the simultaneous fed-batch scenario, respectively. The novel hybrid process was energy-saving, environmentally friendly and profitable, showing promise in future industrialization. [ABSTRACT FROM AUTHOR]

In this study, an integrated gas stripping–pervaporation (GS–PV) process was established to enhance the butanol concentration and to reduce the cost of the product separation processes. Batch pervaporation was integrated with in situ gas stripping system of fed-batch acetone–butanol–ethanol (ABE) fermentation. A total 706.68 g/L ABE (54.2 g/L of ethanol, 169.93 g/L of acetone, and 482.55 g/L of butanol) was collected after 11 h of pervaporation separation. The recovery rates of butanol, acetone and ethanol were 98.8%, 99.5% and 82.8% (w/v), respectively. Attractively, the liquor on the permeate side of pervaporation membrane exceeded its azeotropic point which have not been achieved in previous processes basing on individual gas stripping or pervaporation. Furthermore, aiming to construct consolidate commercial guide of biobutanol producing process, GS–PV–distillation process was established and compared with traditional GS–distillation scheme. As a result, 24.83 MJ/kg of butanol was consumed in the novel GS–PV–distillation process. In this scheme, the beer column was deleted from the rectifying column series. Moreover, based on the consolidate GS–PV–distillation integration process, heat recovery network was simulated and designed by Pinch Analysis, and 1.72 MJ/kg of heat could be further saved after heat exchange in the distillation system. And the overall energy demand for butanol production was further decreased to 23.07 MJ/kg, which was only 29.2% of the conventional distillation procedure. [ABSTRACT FROM AUTHOR]