A systematic approach for screening green entrainers combining the environmental-health-safety indexes and separation performance

Here we propose a new approach for extractive distillation (ED) process design, integrating environmental-health-safety (EHS) indexes as early as during the entrainer screening phase. Typically, safety and environmental factors are addressed later in the design process, often during optimization or in a sequential evaluation after cost-based optimization. However, in this study, we propose for the early incorporation of EHS considerations during the entrainer screening phase. This involves assessing the entrainer suitability using traditional metrics alongside additional EHS criteria, such as lethal dose (LD50) and flash point. Two azeotropic mixtures, i.e., tetrahydrofuran (THF)/ethanol (EtOH) and THF/methanol (MeOH), are chosen to exemplify our proposed methodology. Among the 1432 screened entrainers, the top 10 entrainers were identified based on separation index. These candidates were then subjected to further evaluation based on EHS criteria. Ethylenediamine (EDA) emerged as the optimal choice for the separation of THF/MeOH and THF/EtOH mixtures, demonstrating commendable EHS performance. Both separation processes were successfully simulated using Aspen Plus, which confirms the validity and suitability of the screened entrainer.