Synthesis and design of new hybrid configurations for biobutanol purification

• Biobutanol separation by distillation is not economically sustainable.
• Not so many studies are focused on developing effective separation sequences.
• New alternative configurations were developed using L–L extraction and distillation.
• The alternatives were optimized using the TAC and an environmental impact function.
• Thermally coupled configurations reduced the TAC and the environmental function.

The development of new technologies for biobutanol production by fermentation has resulted in higher butanol concentrations, less by-products and higher volumetric productivities during fermentation. These new technology developments have the potential to provide a production process that is economically viable in comparison to the petrochemical pathway for butanol production. New alternative hybrid configurations based on liquid–liquid extraction and distillation for the biobutanol purification were presented. The alternatives are designed and optimized minimizing two objective functions: the total annual cost (TAC) as an economical index and the eco-indicator 99 as an environmental function. All the new configurations presented reduced the TAC compared to the traditional hybrid configuration, in particular a thermally coupled alternative exhibited a 24.5% reduction of the TAC together with a 11.8% reduction of the environmental indicator. Also intensified sequences represented a promising option in the reduction of the TAC but with some penalty in the eco-indicator.