Optimizing multistage fluidized bed reactor performance: Computational insights and design modifications

Abstract

Multistage fluidized bed reactors (MFBR) offer enhanced gas–solid interactions, longer residence times, and reduced bubble growth compared to conventional fluidized bed reactors, making them promising candidates for carbon capture applications. Understanding the hydrodynamics is crucial for optimizing the reactor design. This study presents a 2D numerical investigation of the hydrodynamics in a two-stage MFBR using the Euler–Euler Two-Fluid model, with the Syamlal O’Brien drag model tuned to experimental minimum fluidization conditions. The predicted pressure drops across the reactor stages closely matched experimental data, validating the model’s accuracy. Key parameters such as clearance height, gas velocity, and particle size were analyzed for their effects on pressure drop, solid holdup, velocity profiles, and solid entrainment flux. Additionally, the power consumption of the MFBR, based on pressure drop, was evaluated and compared to that of a conventional fluidized bed reactor. The results provide critical insights into the hydrodynamic behavior of MFBRs under various operating conditions, offering valuable guidance for optimizing reactor design, particularly for carbon capture using solid sorbents.