Energy-efficient bioethanol recovery process using deep eutectic solvent as entrainer

Bioethanol is commonly recovered from fermentation broth via distillation because it is the most economical and reliable process for large-scale industrial operations. Because extraction is a highly energy-efficient process applicable to low-composition bio-product separation, high-performance solvents are necessary for efficient bioethanol recovery. 2-Methyl pentanol, a branched long-chain alcohol, which was used as the extraction solvent, and a deep eutectic solvent, choline chloride and ethylene glycol (1:2), was employed as an entrainer for product refinement. Thermodynamic models of vapor–liquid equilibrium (VLE) and liquid–liquid equilibrium (LLE) systems were derived using molecular simulations and experimental results to develop the bioethanol extraction and refinement processes. The heat duty of the designed process was reduced by a quarter compared to that of previous recovery processes. Graphic abstract

Predicted Mutual Solubilities in Water + C5-C12 Hydrocarbon Systems. Results at 298 K

Mutual solubilities of water with n-alkanes, cycloalkanes, iso-alkanes (branched alkanes), alkenes, alkynes, alkadienes, and alkylbenzenes were calculated at 298 K for 153 systems not yet measured. Recommended data for 64 systems reported in the literature were compared with the predicted values. The solubility of the hydrocarbons in water was calculated with a thermodynamically based equation, which depends on specific properties of the hydrocarbon. The concentration in the second coexisting liquid phase (water in hydrocarbon) was calculated using liquid-liquid equilibrium with an equation of state, which takes into account the self-association of water and co-association of water with π-bonds of the hydrocarbons.