Upgrading of raw biogas to CNG quality

We explore innovative methods for upgrading biogas to CNG quality using various membrane technologies. Primarily, we investigate the incorporation of ionic liquids into polymer membranes on CO₂/CH₄ separation and we utilize molecular dynamics simulation to understand the interplay of gas sorption and permeation in gas mixtures. Additionally, we evaluate the performance of either mixed matrix membranes with functional fillers as graphene oxide/metal-organic framework or ultrapermeable polymers of intrinsic microporosity, demonstrating significant improvements in CO₂ permeability while maintaining good performance stability in gas mixtures. Finally, we explore the effectiveness of water-swollen composite membranes for separating CH₄ from other raw biogas species, achieving high methane recovery ratios and efficient desulfurization.

Trade-off diagram CO₂/CH₄ for PIM-TMN-Trip membrane for pure gases and gas mixtures. MD model for 10-mer with 20 wt.% ionic liquid and mixture CO₂+CH₄. Trade-off diagram CO₂/CH₄ for poly(ionicliquids)

• Wojnarova P., Rusin J., Basinas P., Kostejn M., Nemec J., Stanovský P., Kim A. S., Izak P.: Unveiling the potential of composite water-swollen spiral wound membrane for design of low-cost raw biogas purification. Sep. Purif. Technol. 326(1 Dec), 124783, 2023. DOI
• Stanovský P., Benkocká M, Kolská Z., Šimčík M., Slepička P., Švorčík V., Friess K., Ruzicka M.C., Izak P.: Permeability enhancement of chemically modified and grafted polyamide layer of thin-film composite membranes for biogas upgrading. J. Membr. Sci. 641(1 Jan), 119890, 2022. DOI
• Jung A., Reha D., Minofar B., Stanovsky P., Pasichnyk M., Pribyl M., Bara J. E., Friess K., Fila V., Izak P.: Molecular simulation of poly(VDF-HFP) copolymer with imidazolium-based ionic liquid as an effective medium for biogas separation. J. Mol. Liq. 366(15 Nov), 120287, 2022. DOI
• Stanovsky P., Karaszova M., Petrusova Z., Monteleone M., Jansen J.C., Comesana-Gandara B., McKeown N.B., Izak P.: Upgrading of raw biogas using membranes based on the ultrapermeable polymer of intrinsic microporosity PIM-TMN-Trip. J. Membr. Sci. 618(15 Jan), 118694, 2021. DOI
• Friess K., Izak P., Karaszova M., Pasichnyk M., Lanc M., Nikolaeva D., Luis P., Jansen J.C.: A Review on Ionic Liquid Gas Separation Membranes. Membranes 11(2), 97, 2021. DOI
• Levdansky V., Solcova O., Friess K., Izak P.: Mass Transfer Through Graphene-Based Membranes. Appl. Sci. 10(2), 455, 2020. DOI
• Zak M., Bendova H., Friess K., Bara J.E., Izak P.: Single-step purification of raw biogas to biomethane quality by hollow fiber membranes without any pretreatment-An innovation in biogas upgrading. Sep. Purif. Technol. 203(12 Sep), 36-40, 2018. DOI