Techno-Economic Analysis of Cellulosic Butanol Production from Corn Stover through Acetone–Butanol–Ethanol Fermentation

Biobutanol has fuel properties comparable to those of gasoline; however, its commercial production through acetone–butanol–ethanol (ABE) fermentation from lignocellulosic biomass is still encumbering due to low product yield, energy extensive recovery method, and butanol toxicity to microbes. Recent development of simultaneous saccharification, vacuum fermentation, and recovery technique has the potential to reduce these problems and improve butanol yield, which has gained significant attention as an emerging alternative way for ABE fermentation. Thus, the main objective of this study was to assess the techno-economic feasibility of commercial-scale ABE fermentation for a 113.4 million L/year (30 million gal/year) butanol production and identify operational targets for process improvement. Commercial dilute sulfuric acid pretreatment and corn stover feedstock were used in this study. Experimental data on the pretreatment of corn stover and the ABE fermentation and recovery were gathered from recent publications. Process modeling and economic analyses were performed using a modeling software, SuperPro Designer. Estimated butanol production costs were $1.8/L and $1.5/L without and with byproduct credits. Butanol recovery was identified to be the most sensitive parameter followed by sugar utilization in the fermentation reactor, feedstock cost, corn stover to sugars conversion rate, and heat recovery. Furthermore, optimizing these sensitive operating parameters could reduce the butanol production cost to $0.6/L, which is competitive with current gasoline prices; however, achieving these targets will require further research and development efforts on the ABE fermentation.