Reaction Characteristics of Ni-Based Catalyst Supported by Al2O3 in a Fluidized Bed for CO2 Methanation

CO2 methanation is a promising technology to store renewable energy by converting carbon dioxide with green hydrogen into methane, which is known as power to gas (PtG). In this study, CO2 methanation performance of a Ni/Al2O3 catalyst was investigated in a bubbling fluidized bed (BFB) and the axial gas concentration, temperature, and CO2 conversion were densely analyzed. Moreover, a modified reaction kinetic model was proposed, and the results were compared with experimental data. The bed temperature increased by 11 degrees C from 340 degrees C to 351 degrees C within the first 30 mm of the fluidized bed. The CO2 conversion was approximately 90% within 50 mm from the bottom of the reactor and was maintained above this height. The Ni/Al2O3 catalyst exhibited the highest CO2 conversion (95%) at 320 degrees C. Using a simple plug-flow reactor model, three optimized kinetic modification factors (1.5094, 0.0238, and 0.2466) were used to fit the experimental data. The hydrodynamic effects significantly influenced the chemical reaction kinetics of the BFB.

Automated summary

This study investigates the CO2 methanation performance of a Ni/Al2O3 catalyst in a bubbling fluidized bed, and proposes a modified reaction kinetic model. The experimental results show that the Ni/Al2O3 catalyst has the highest CO2 conversion at 320 degrees C.