Selection of eco-efficient downstream separation configuration for isopropanol–butanol–ethanol purification process

Nowadays, renewable and cleaner biofuel requirements increase with the increase in economic, environmental, and social concerns. Biobutanol is a preferable alternative fuel due to its outstanding properties compared to other alcohol-based biofuels. Two alternative downstream process configurations are designed in this study to obtain high-purity alcohol products from isopropanol–butanol–ethanol (IBE) fermentation broth with the same feed flowrate and compositions. In process configuration 1, the excess amount of water in the fermentation broth is mainly taken away using a preconcentration column. In process configuration 2, an extractor-extractive distillation hybrid system is used to remove the excess amount of water from the system. The results show that the first configuration is superior with a 62% reduction in total annual cost (TAC). Besides economic superiority, process configuration 1 is also quantitatively better than process configuration 2 in terms of gas emissions and energy demand to purify butanol. As a result, process configuration 1 is found as an eco-efficient downstream separation sequence for IBE purification process.