Title : Catalytic Hydrogenation of CO2 to Methanol over Cu/ZnO Based Catalyst: Effect of Different Shapes of Al2O3 Pellet Support
CO2 management is vital for ensuring the economic and environment viability especially for monetization of high CO2 field. In view of this outstanding challenges, CO2 is not seen any more as a waste but as an alternative carbon feedstock to transform this stable molecule into useful chemicals and energy carriers. Conversion of CO2 to valuable product is a challenging contemporary issue, but with the development of optimized process catalyst, the challenges can be overcome. CO2 catalytic conversion to fuel (methanol) has been studied as one of the strategies to reduce CO2 emission and can be considered as a complementary technology to CCS, serving similar goals, while additionally providing economic benefits. The study focused on catalytic conversion of CO2 to methanol over promoted Cu/ZnO based catalyst supported on various shapes of Al2O3 pellets support (spherical, hollow extrudate and trilobe extrudate). The catalysts were synthesized by impregnation method with fixed metal loading. The aqueous precursor solution was impregnated on the Al2O3 pellets support, maintained at pH 7, continuously stirred, filtered and washed. It was then dried, grinded and calcined at 350 °C. The synthesized catalysts were characterized using H2-TPR, FESEM, N2 adsorption desorption and XRD. The performance of the synthesized catalysts in a CO2 hydrogenation reaction was evaluated in a fixed-bed reactor. The reaction temperature, pressure, GHSV and H2: CO2 molar ratio were fixed to study the effect of different shapes of Al2O3 pellets support on the catalytic performance. The experimental findings indicate that, the shape of Al2O3 pellet gave significant impact on CO2 conversion and MeOH selectivity. The catalyst with spherical shape resulted in highest CO2 conversion and MeOH selectivity at 11.83% and 51.84% respectively. The two catalysts samples with the same shape (hollow extrudate) but different dimensions resulted in CO2 conversion at 11.46% and 11.00% and MeOH selectivity at 45.58% and 40.84%. The trilobe extrudate gives out lowest CO2 conversion at 10.30%, however higher MeOH selectivity as compared to one of the hollow extrudate at 43.43%. It can be concluded that, the shape of the catalysts influence the catalytic performance significantly.