Involving economic, environmental and safety issues in the optimal purification of biobutanol

Traditionally, the design of a separation sequence for the biobutanol production has been based primarily on economic criteria with little or no consideration to the environmental and safety issues. Since biobutanol is produced from acetone-butanol-ethanol (ABE) fermentation, the process involves several substances that may cause fire and explosion and can lead to negative environmental and health impact. Hence, it is desirable to incorporate safety and environmental issues in the design objectives to determine the optimal separation route. This work presents an optimization approach for the biobutanol separation process from the ABE fermentation while accounting simultaneously for economic, environmental and safety objectives. The optimization is carried out through a differential evolution with a Tabu search algorithm, where several Pareto solutions are identified and some routes are highlighted to determine the best compensated solutions. In this case, the best economic solution involves elevated values of the Eco-Indicator 99, the best environmental solution incurs high costs, and the safest solution features less separation columns. The most compensated solutions include configurations that represent a balance among the economic, environmental and safety objectives.