Direct Conversion of Carbon Dioxide to Methane over Ceria‐ and Alumina‐Supported Nickel Catalysts for Biogas Valorization
Wojciech Gac, Witold Zawadzki, Marek Rotko, Magdalena Greluk, Grzegorz Słowik, Helmut Pennemann, Stefan Neuberg, Ralf Zapf, Gunther Kolb
Abstract
Abstract Direct methanation of CO 2 over ceria‐ and alumina‐supported nickel catalysts in the feed stream containing methane and traces of H 2 S is reported. Stability tests for 20 h at 350 and 600 °C with a packed‐bed reactor showed high resistance of the catalysts to sintering processes. Higher conversion at 350 °C was observed for ceria supported nickel catalyst. Thermodynamic analysis indicated that CO 2 contained in biogas can be converted to methane without carbon formation under specific reaction conditions. An introduction of CH 4 to CO 2 −H 2 feed stream led to the decrease in CO 2 conversion and CH 4 selectivity. An introduction of the trace amounts of H 2 S into the feed stream led to the fast drop of CO 2 conversion and CH 4 selectivity; higher durability (20 %) was observed for Al 2 O 3 than CeO 2 supported catalysts. An improved performance of catalysts coated onto high‐pressure microchannel microreactors for the direct CO 2 methanation reaction applying model biogas mixture was demonstrated.