Hierarchical Ionic Liquid Screening Integrating COSMO-RS and Aspen Plus for Selective Recovery of Hydrofluorocarbons and Hydrofluoroolefins from a Refrigerant Blend

The selective recovery of hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs) from end-of-life equipment is regarded as an efficient and sustainable way for their reclamation, thereby reducing the production and emission of HFCs with high global warming potential. A R454C blend constituted of difluoromethane (R-32) and 2,3,3,3-tetrafluoropropene (R-1234yf) is a nontoxic and mildly flammable refrigerant ideally suitable for hermetically sealed refrigeration systems. This work presents a hierarchical screening of ionic liquids (ILs) for R-32 and R-1234yf recovery from R454C. First, 1093 HFC/HFO-in-IL solubility data (543 for R-32 and 550 for R-1234yf) are collected from the literature to evaluate the reliability of the COSMO-RS model for this system. Then, the solubility of R-32 and R-1234yf in 2224 ILs composed of 59 cations and 38 anions is predicted by COSMO-RS; following that, the IL structural effects on gas solubility are analyzed according to σ-profiles and excess energies. Subsequently, combining the thermodynamic performance and the melting point constraint, the top six ILs among the involved ILs are identified. Based on the retained ILs, a continuous absorption is simulated and evaluated in Aspen Plus, demonstrating that ILs n-(3-sulfopropyl)­pyridinium thiocyanate and n-(3-sulfopropyl)­pyridinium hydrogensulfate are promising absorbents from the process point of view.从报废设备中选择性回收氢氟烃（HFCs）与氢氟烯烃（HFOs），被视为实现其回收再利用的高效可持续路径，可由此减少具有高全球变暖潜势的HFCs的生产与排放。由二氟甲烷（R-32）与2,3,3,3-四氟丙烯（R-1234yf）组成的R454C混合制冷剂，是一种无毒、微易燃的制冷剂，非常适用于密闭式制冷系统。本研究针对从R454C混合制冷剂中回收R-32与R-1234yf的需求，开展了离子液体（ILs）的层级筛选工作。首先，从公开文献中收集了1093组HFC/HFO在离子液体中的溶解度数据（其中R-32相关数据543组，R-1234yf相关数据550组），以评估COSMO-RS模型在该体系中的可靠性。随后，通过COSMO-RS模型预测了R-32与R-1234yf在由59种阳离子和38种阴离子构成的2224种离子液体中的溶解度；进而基于σ-轮廓与超额能量，分析了离子液体的结构对气体溶解度的影响规律。继而结合热力学性能与熔点约束条件，从所筛选的离子液体中遴选出性能最优的6种离子液体。基于筛选得到的离子液体，借助Aspen Plus软件对连续吸收过程进行模拟与评估，结果表明：硫氰酸n-(3-磺丙基)吡啶鎓与硫酸氢n-(3-磺丙基)吡啶鎓这两种离子液体，从工艺角度而言是极具应用前景的吸收剂。