Upgrading of Biogas Using Supported Ionic Liquid Phase (SILP) Materials Leonard Schill1; Frederik Bork Jansen1; Christian Weibel1; Anders Riisager2; Rasmus Fehrmann1; 1DTU CHEMISTRY, Lyngby, Denmark; 2DTU CHEMISTRY, Kgs. Lyngby, Denmark; PAPER: 72/Molten/Regular (Oral) SCHEDULED: 14:00/Tue./Bossa (150/3rd) ABSTRACT: Upgrading of biogas requires the removal of both CO<sub>2</sub> and H<sub>2</sub>S. Amino Acid based ionic liquids (AA-ILs) are known to efficiently remove CO2 by binding to the carboxylate group and DFT studies suggest that H<sub>2</sub>S can bind to both the carboxylate and the amine group of the amino acid anion. This study has demonstrated that that indeed two moles of H<sub>2</sub>S can bind to one mole of [P4444][Pro] even when a highly dilute stream (750 ppm) is used. Adsorption to the stronger sites (amine groups) is possible even in the presence of a vast excess of CO<sub>2</sub>. There is reason to believe that H<sub>2</sub>S removal levels of > 90 % could be maintained for several days at a space velocity of 100 h-1 with an H<sub>2</sub>S inlet concentration of 750 ppm. Potential pressure drop problems were solved by impregnating the ionic liquid onto mesoporous pellets prepared by a simple and scalable technique. H<sub>2</sub>S removal under relatively mild conditions (60 °C, 50 mbar) was unsuccessful and raises concerns about the ability to regenerate [P4444][Pro]. This might also mean that pure CO<sub>2</sub> removal using [P4444][Pro] requires gas streams practically free of H<sub>2</sub>S. References: [1] Angelidaki, I.; Treu, L.; Tsapekos, P.; Luo, G.; Campanaro, S.; Wenzel, H.; Kougias, P. G. Biogas upgrading and utilization: Current status and perspectives. Biotechnology Advances 2018, 36, 452-466, doi:10.1016/j.biotechadv.2018.01.011. [2] Strauch, S.; Krassowski, J.; Singhal, A. Biomethane Guide for Decision Makers Policy - guide on biogas injection into the natural gas grid. Frauenhaofer UMSICHT, Research group biogas technology 2013. http://www.greengasgrids.eu/fileadmin/greengas/media/Downloads/Documentation_from_the_GreenGasGrids_project/Biomethane_Guide_for_Decision_Makers.pdf [3] Liu, S.; Zhou, H.; Song, Q.; Ma, Z. Journal of the Taiwan Institute of Chemical Engineers Synthesis of higher alcohols from CO 2 hydrogenation over Mo-Co-K sulfide-based catalysts. 2017, 76, 18-26, doi:10.1016/j.jtice.2017.04.007. [4] Kaas-Larsen, P. K.; Thomassen, P.; Schill, L.; Mossin, S.; Riisager, A.; Fehrmann, R. Selective Reversible Absorption of the Industrial Off-Gas Components CO 2 and NO. ECS Trans. 2016, 75, 3-16, doi:10.1149/07515.0003ecst. [5] Jansen, F. B.; Weibel, C. Selective absorption of gases by ionic liquids. Bachelor Thesis, Technical University of Denmark, Kgs. Lyngby, Denmark 2017. |