Polymer/ionic liquid pilot scale membrane prototype for the recovery of difluoromethane (R-32) from refrigerant mixtures
Difluoromethane (R-32) is a hydrofluorocarbon (HFC) that has been massively used over the last 30 years in refrigeration and air conditioning as a primary component of azeotropic or close boiling refrigerant mixtures. Despite environmental directives commanded to drastically reduce the use of HFCs,...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universidad de Cantabria (UC) |
| Repositorio: | UCrea Repositorio Abierto de la Universidad de Cantabria |
| Idioma: | inglés |
| OAI Identifier: | oai:repositorio.unican.es:10902/29174 |
| Acceso en línea: | https://hdl.handle.net/10902/29174 |
| Access Level: | acceso abierto |
| Palabra clave: | Thin film composite Spray coating Fluorinated hydrocarbon Gas separation Scale-up Pebax membrane |
| Sumario: | Difluoromethane (R-32) is a hydrofluorocarbon (HFC) that has been massively used over the last 30 years in refrigeration and air conditioning as a primary component of azeotropic or close boiling refrigerant mixtures. Despite environmental directives commanded to drastically reduce the use of HFCs, R-32 has excellent thermodynamic properties and moderate GWP, thus its recovery from depleted mixtures collected from end-of-life equipment is sought to synthesize alternative low-GWP refrigerant blends. Membrane separation using composite polymer/ionic liquid membranes based on poly-ether-block-amide have shown potential to separate R-32 from other fluorinated hydrocarbons, yet the development of this type of composite membranes still remains at laboratory scale. In this work, a spray coating technique was successfully applied to create defect-free thin selective layers of neat Pebax®1657, Pebax®1657/40 wt% [C2C1im][BF4] and Pebax®1657/40 wt% [C2C1im][SCN] coated on porous PVDF substrates. This methodology was transferred from the lab-scale tests (12.6 cm2) to a custom pilot set-up (300 cm2). The pilot results confirmed the superior performance and stability of [C2C1im][SCN]-based membranes, which allowed the recovery of up to 64.3% and 67.1% R-32 from the refrigerant mixtures R-410A (69.8 mol % R-32 and 30.2 mol % R-125) and R-454B (82.1 mol % R-32 and 17.9 mol % R-1234yf) at 6 bar, increasing the R-32 permeate concentration up to 89.6 and 95.9 mol %, respectively. These results highlight the need to expand the knowledge of this type of gas separation membranes towards thinner and defect-free selective dense layers with the purpose of approaching their real applications. |
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