Regular articleA process integration approach for the production of biological iso-propanol, butanol and ethanol using gas stripping and adsorption as recovery methods

- “In-situ” alcohols recovery from fermentation broth using gas-stripping.
- Gas-phase adsorption of Isopropanol, Butanol and Ethanol (IBE) to activated carbon.
- Development of an efficient large-scale IBE plant using mathematical modeling.
- Integration of fermentation, stripping, adsorption, condensation and distillation.

Biomass fermentation to Iso-propanol, Butanol and Ethanol (IBE) is particularly important as IBE is a common building block in the development of biorefineries and IBE-producing bacteria are robust industrial organisms, capable to utilize the sugars of the lignocellulosic biomass. Research is focused on increasing fermentation yields and the reduction of energy that is required to separate the volatile products. The paper addresses both of these challenges combining experimental innovations with a systems engineering approach. IBE is recovered from a gas-stripped fermenter whose potential for adsorption is researched and integrated with downstream options for separation. Design and integration is assisted using a systems approach that relies on mathematical models that regress and extrapolate experimental data for scale-up calculations. Process integration involves synthesis challenges to define biorefinery portfolios and systems integration to combine fermentation, stripping, adsorption, and distillation. The analysis considers 4 alternative biorefinery cases and presents results with significant savings in energy use and costs (up to 87% savings reported) after the application of energy integration to the IBE plant. Scenarios are analysed economically and confirm benefits in the use of adsorption and viable production yields.