Numerical modeling of the cavity phenomenon and its elimination way in rectangular radial moving bed reactor

• Develop a comprehensive three-dimensional two-phase reactor model.
• Investigate the effects of bed voidage and solid-seal height on the cavity phenomenon.
• Understand the cavity phenomenon in moving beds using the modeling approach.
• Optimize reactor operating conditions for eliminating the cavity.
• Propose a novel trapezoidal structure for alleviating the cavity phenomenon.

A complete three-dimensional (3D) reactor model based on the Eulerian–Eulerian two-fluid approach was developed to assist in the understanding of the cavity phenomenon in rectangular radial flow moving bed reactors (RFMBRs). The effectiveness of proposed model was firstly validated by the experimental data. The simulation results showed that the cavity phenomenon appears on the top of catalyst bed and the cavity scale increases with the increase of the superficial gas velocity. The effects of bed voidage and solid-seal height on the formation of cavity were thoroughly investigated. It was demonstrated that an appropriate high bed voidage and solid-seal height can effectively reduce the occurrence possibility of the cavity. Moreover, it was found that a trapezoidal structure is helpful to alleviate the cavity phenomenon in RFMBRs. It is thus concluded that a numerical modeling technique provides a promising approach to eliminate the unfavorable two-phase flow as well as improve the flexibility and efficiency in RFMBRs.

Schematic diagram of simulated cavity phenomenon and its optimization in rectangular radial moving bed reactor.Figure optionsDownload as PowerPoint slide