The phase-down of hydrofluorocarbons (HFCs) established by the Kigali Amendment to the Montreal Protocol is leading to the formulation and commercialization of new refrigerant blends containing hydrofluoroolefins (HFOs), such as 2,3,3,3-tetrafluoropropene (R1234yf), and HFCs with moderate global warming potential, namely, difluoromethane (R32 ) and 1,1,1,2tetrafluoroethane (R134a). Moreover, the recycling of refrigerants is attracting attention as a means to reduce the amount of new HFCs produced and their release to the environment. To that end, the use of ionic liquids has been proposed as entrainers to separate refrigerants with close-boiling points or azeotropic blends. Thus, the vapor-liquid equilibria and diffusion coefficients of the refrigerant-ionic liquid pairs formed by R32 +studied using an isochoric saturation method at temperatures ranging from 283.15 to 323.15 K and pressures up to 0.9 MPa. In addition, the solubility behavior is successfully modeled using the non-random two-liquid activity coefficient method, and the Henry's law constants at infinite dilution, solvation energies and infinite dilution activity coefficients are calculated.
Hydrofluorocarbons (HFCs) are powerful greenhouse gases whose production and consumption must be phased-down in order to reach the reduction goals established by the Kigali Amendment to the Montreal Protocol. However, the share of recycled refrigerant gases remains very low owing to the extremely inefficient separation of refrigerant mixtures by cryogenic distillation. In this sense, the HFCs difluoromethane (R32, GWP = 675) and 1,1,1,2tetrafluoroethane (R134a, GWP = 1430), together with the hydrofluoroolefin (HFO) 2,3,3,3tetrafluoropropene (R1234yf, GWP = 4), are among the most common constituents of HFC/HFO refrigerant mixtures currently employed in the refrigeration and air conditioning sector. Therefore, the feasibility of using membrane technology for the selective separation of these compounds is assessed in this work for the first time. A comprehensive study of their gas permeation through several poly(ether-block-amide) (PEBA) membranes that differ on the content and type of backbone segments is performed. Results show that PEBA membranes exhibit superior permeability of R32 (up to 305 barrer) and R134a (up to 230 barrer) coupled with reasonably high selectivity for the gas pairs R32/R1234yf (up to 10) and R134a/R1234yf (up to 8). Moreover, for the blends R32/R1234yf and R32/R134a, the membrane separation performance is not significantly affected under the mixed-gas conditions tested. Thus, results evidence that consideration should be given to membrane technology for the cost-efficient separation of HFCs/HFOs mixtures in order to boost the recycling of these compounds.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.