Multiobjective Optimal Acetone–Butanol–Ethanol Separation Systems Using Liquid–Liquid Extraction-Assisted Divided Wall Columns

Abstract

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.

Analysis of intensified sustainable schemes for biobutanol purification

“…As far as the authors are aware, no study has been carried out on the sustainability and inherent safety of the purification section, based on the liquid-liquid extraction and DWC, of the butanol, acetone, ethanol, and water mixture. In this work, we study the configurations proposed by Errico et al [18] to analyze their sustainability, based on the green metrics proposed by Jiménez-González et al [23]. Their inherent security is complemented with the analysis of open-loop control properties with the technique of singular value decomposition.…”

“…Previously, Errico et al [18] presented a complete synthesis methodology to generate separation alternatives to purify biobutanol. In brief, the methodology starts from a hybrid process design with a liquid-liquid extractive column and a set of three conventional distillation columns.…”

“…In brief, the methodology starts from a hybrid process design with a liquid-liquid extractive column and a set of three conventional distillation columns. Considering a base case, Errico et al [18] applied a systematic methodology to produce several alternatives, liquid-liquid extraction-assisted conventional J o u r n a l P r e -p r o o f DWC configurations, and liquid-liquid extraction-assisted nonconventional DWC configurations. All those alternatives were designed considering the NRTL-HOC as a thermodynamic model to describe phase equilibrium.…”

“…Okoli and Adams [17] studied the separation of butanol in a quaternary DWC, by minimizing TAC, as an objective function. Errico et al [18] explored DWC as a promising intensified distillation alternative in combination with liquid-liquid extraction. Their results indicated a reduction of 22% and 18% in the economy and the environmental indices, respectively.…”

Inherently Safer Design and Optimization of Intensified Separation Processes for Furfural Production

“…In case of distillation columns, the factors that have the strongest influence on EI99 are the steam used to supply the heat duty, electricity utilized for pumping of cooling water, and the steel necessary to build the equipment. 19,30 The eco-indicator 99 can be represented mathematically according to Eq. 2 as follows: 99…”