Solvent Recycle and Impurity Purge Evaluation for Organosolv Pretreatment Method for Bioethanol Production from Lignocellulosic Biomass

Experimental works showed that organosolv pretreatment is a promising method for bioethanol production from high lignin content biomass. From process design point of view, the solvent processing units together with the solvent recovery and recycle use have significant effects on the process synthesis, process structure and process economy. In this work, we propose a systematic methodology to select and evaluate the purge rate and placement for the solvent recycle and reuse for organosolv pretreatment. Evaluation parameters such as the desired solvent composition, inhibitors presence, fresh solvent intake amount, total annual costs (TAC) and minimum ethanol selling price (MESP) were compared. Results showed that different placements and rates of the purge stream can lead to an increase of 6.6 % and 10.8 % in the impurities concentration and MESP, respectively, when compared to the best case simulated.