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초록

Catalytic methane decomposition (CMD) in a fluidized bed reactor (FBR) offers a promising method for producing clean hydrogen and valuable carbon materials such as carbon nanotubes (CNTs). Finding the proper fluidization regime is crucial for achieving high carbon purity in solid products as their properties evolve with catalyst usage over time. In this study, a computational particle fluid dynamics (CPFD) model based on the Eulerian-Lagrangian framework was employed to predict bed dynamics in a continuous CMD-FBR. A drag force multiplier was introduced to account for porosity variations in the solid product particles associated with different carbon yields. The model was validated against experimental data obtained from a 3-inch fluidized bed column for carbon yields of 50 % and 300 %. The simulation accurately predicted bed density and bubble dynamics with less than 10 % error. Based on this model, it revealed that at higher superficial gas velocities (9 cm/s vs. 4.5 cm/s), increased bubble activity reduced solid segregation but decreased carbon purity from 72 wt% to 39 wt%. These findings prove the model's potential to optimize operating conditions for enhanced CMD process efficiency and product quality.

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