Cost- and Energy-Efficient Butanol-Based Extraction-Assisted Distillation Designs for Purification of 2,3-Butanediol for Use as a Drop-in Fuel

2,3-Butanediol has attracted interest as a promising drop-in fuel, mainly due to its high antiknock index and high heating value. Microbial production of 2,3-butanediol is considered more environmentally friendly and sustainable than chemical-based production methods. However, to achieve the 99% purity required for use as fuel, the dehydration and purification steps associated with the microbial production process consume tremendous amounts of energy. This high energy consumption limits the feasibility of the microbial production process at the commercial scale. A commercially feasible and sustainable 2,3-butanediol production process is proposed based on an energy efficient extraction-assisted distillation scheme. On the basis of economic, technical, and environmental considerations, isobutyl alcohol and 1-butanol were chosen as suitable solvents for the proposed scheme. Regression analysis and data validation were applied to verify the incorporated experimental data which was then used in the well-established commercial process simulator Aspen Plus. Results indicate that the overall energy efficiency of the purification step of the microbial 2,3-butanediol production process can be improved greatly, with up to 24.5% and 31.3% reductions in total annualized cost for the isobutyl alcohol- and 1-butanol-based designs, respectively.