Methanation of simulated natural gas using alumina supported managanese doped ruthenium and palladium oxide catalyst

Abstract

Malaysian crude natural gas categorized as a sour gas due to the contamination of CO2 other gases. Therefore in this research, manganese oxide doped noble metal oxides suppor ted on alumina were prepared for methanation reaction to convert CO2 to CH4. All prepared Ru/Mn-Al2O3(10:90, 20:80, 25:75, 30:70, 35:75 and 40:60) catalysts were calcined at 400ºC, and 1000ºC and Pd/Mn-Al2O3(10:90 and 30:70) catalysts were only calcined at 400ºC for 5 hours separately in screening process.Ru/Mn(25:75)-Al2O3 catalyst then being calcined at 700°C, 800°C, 900°C and 1100°C for optimization parameter. In-house-built micro reactor with Fourier Transform Infra Red, (FTIR) detector and Gas Chromatography, (GC) were used to study the catalytic activity. It was found that the catalyst with Ru/Mn(25:75)-Al2O3 calcined at 1000oC showed 60.21% conversion of CO2 and 57.84% formation of CH4 at reaction temperature 200oC. When using two series furnace reactors, Ru/Mn(25:75)-Al2O3 catalyst calcined at 1000oC achieved 95.12% CO2 conversion and 53.10% CH4 formation at reaction temperature 100°C. The same catalyst with coating more than one coat reducing the catalytic reaction compared with single coat. The catalyst finally reached 100% CO2 conversion with 100% CH4 formation after through the 3rd testing using 100°C of reaction temperature. In pretreatment testing, the catalyst managed to get 100% CO2 conversion with 100% CH4 formation at first test at reaction temperature 100°C. For adding compressed gas (O2) testing, the catalyst shows 100% of CO2 conversion with 100% CH4 formation with only 6% of compressed gas loading at reactiontemperature 100°C. Using 1% of H2S, reduce the potential of the catalyst compared with using 0.5% of H2S feed. FESEM illustrated the catalyst surface is covered with small and dispersed particles with undefined shape. The X-Ray Diffraction (XRD) analysis revealed that the catalyst is crystalline. Nitrogen Gas Adsorption (NA) analysis showed that both fresh and spent catalysts are of mesoporous material with Type IV isotherm and type H3 hysteresis loop.