Methanation of carbon dioxide over Ru/Mn/Ce-Al2O3 catalyst: In-depth of surface optimization, regeneration and reactor scale

Abstract

Converting the CO2 gas via catalytic methanation technology has significant potential application in the power plant industry. Therefore, ceria based catalyst impregnated with Ru/Mn/Al2O3 was developed and from the experimental results, the optimum conditions over potential Ru/Mn/Ce (5:30:65)/Al2O3 catalyst was achieved with 65 wt% of Ce based loading calcined at 1000 °C gave 97.73% of CO2 conversion with 91.31% of CH4 at 200 °C of reaction temperature. 10 g of the potential catalyst was pre-reduced at 300 °C for 30 min in the presence of H2 gas prior to the start of catalytic testing. The reliability, robustness, reproducibility and regeneration testing of this catalyst were further studied. The catalyst started to deactivate (spent catalyst) at sixth testing with only gave 41.17% CO2 conversion. However, the catalyst can be regenerated in the presence of compressed air at 400 °C for 3 h as it gave 92.85% of CO2 conversion. From the characterization of spent catalyst, the factor for the catalyst deactivation in this reaction was the particle agglomeration due to the loss of RuO2 and Mn2O3 species. When the catalyst was scale-up, the result showed that Ru/Mn/Ce (5:30:65)/Al2O3 catalyst able to convert 60% of CO2 and 50.4% of methane formation at lower reaction temperature of 160 °C.