Industrial & Engineering Chemistry Research, Vol.56, No.40, 11575-11583, 2017
Multiobjective Optimal Acetone-Butanol-Ethanol Separation Systems Using Liquid-Liquid Extraction-Assisted Divided Wall Columns
Biobutanol is receiving great interest from both the academia and industry sectors, and some companies are already focusing on revamping bioethanol plants to produce biobutanol. The recovery of fuel grade butanol by distillation was proven not to be economically sustainable. On the other side, hybrid flowsheets, obtained with the combination of liquid liquid extraction and distillation, were proposed as a more convenient alternative. Divided wall columns (DWCs), as one of the most promising intensified distillation alternatives, were here explored in combination with liquid liquid extraction. A multiple-objective function, taking into account the economy, the environmental impact, and the process controllability, was defined to screen the alternatives. Among all the configurations considered, liquid-liquid extraction combined with a DWC equipped with two reboilers and a side rectifier, reached 22% and 18% reduction of the economy and environmental index, respectively. At the same time, also the controllability was improved compared to the hybrid liquid liquid-assisted simple column distillation sequence considered as a reference.