Effective permeability of binary mixture of carbon dioxide and methane and pre-dried raw biogas in supported ionic liquid membranes

•The influence of temperature and stage cut on gas permeation through SILM were measured.•Results obtained with binary mixture and real pre-dried biogas were compared.•The SILMs can be used with real pre-dried biogas. The influence of the temperature and stage cut on permeation of CO2 and CH4 through two different supported ionic liquid membranes were studied. The measurements were performed with binary mixture of CH4 and CO2 and with real pre-dried biogas collected in sewage plant. The influence of temperature on permeability followed the Arrhenius behavior in agreement with solution diffusion model of transport. The influence of stage cut was also very small, what helped to confirm that the membrane was operated under optimal conditions. The results obtained with real pre-dried biogas were very close to those obtained with the binary mixture. This was caused by the fact that the amount of trace compounds present in real pre-dried biogas was very small (less than 1vol.%). The results showed that supported ionic liquid membranes (SILMs) can be used for biogas upgrading. It can be also concluded that the use of model mixture instead of real biogas for measurements brings relevant results.