Ionic Liquid-Assisted\nExtractive Distillation for\nEthylene/Ethane Separation: Molecular Design and Process Assessment

In the petrochemical industry, the separation of ethylene\nand ethane\nis a crucial step in ethylene production due to its significant energy\nconsumption, high costs, and environmental impact. This study proposes\nan extractive distillation (ED) method for ethylene/ethane separation\nincorporating a customized ionic liquid (IL) solvent as an extractant.\nThe CAILD (computer-aided ionic liquid design) approach was used for\nsolvent screening. By solving a formulated MINLP (mixed-integer nonlinear\nprogramming) problem based on CAILD, methylpyridinium trifluoroacetate\n([C<sub>1</sub>Py][TFA]) and methylimidazolium trifluoroacetate ([C<sub>1</sub>Im][TFA]) (CAS number 104290-54-2) were identified as the\noptimal IL solvents. Subsequently, rigorous process simulations of\nIL-assisted ethylene/ethane separation were conducted with Aspen Plus.\nFinally, a comprehensive assessment covering energy, environmental,\nand economic aspects was performed. The results demonstrate that,\ncompared to conventional separation processes, the [C<sub>1</sub>Py][TFA]\nand [C<sub>1</sub>Im][TFA]-assisted processes achieve total annual\ncost reductions of 46.51% and 69.82%, respectively. Additionally,\nenergy consumption is decreased by 41.60% and 42.16%, leading to a\nreduction in greenhouse gas emissions by 34.00% and 34.65%, respectively.