Replacing DMF with ionic liquid in isoprene/n-pentane separation in C5 plants: Solvent design, process optimization, and industrial-scale assessment

Abstract

In the petrochemical industries, separating isoprene and n-pentane in carbon-five plants has received significant interest because of relatively high energy consumption and carbon emissions. To address these issues, an energy-efficient isoprene/n-pentane extractive distillation (ED) separation process is designed, incorporating a tailor-made ionic liquid (IL) using the computer-aided ionic liquid design (CAILD) model. By addressing a mixed-integer nonlinear programming (MINLP) model based on CAILD, three optimal IL solvents, namely [MPy][TFA], [C1MPy][TFA], and [C2MPy][TFA], from 584,779 structurally potential IL solvents are identified. The performance of these ILs in isoprene/n-pentane separation in C5 plants is evaluated using rigorous process simulations in Aspen Plus. Subsequently, a comprehensive analysis is conducted, encompassing energy, environmental, and economic evaluations of the industrial-scale separation of isoprene/n-pentane. Notably, the [MPy][TFA]-based separation process exhibits the highest improvements in energy efficiency (69.8%), environmental sustainability (57.7%), and economic viability (30.0%) when compared to the conventional DMF-based separation process commonly used in industries. These findings underscore the significant potential of ILs for sustainable research in the field of isoprene and n-pentane separation.