CFD Modeling and Simulation of the Axial Dispersion Characteristics of a Fixed-Bed Reactor.

In this study, the axial dispersion characteristics of a fixed-bed reactor with different packed structures were investigated via computational fluid dynamics (CFD) simulation. The discrete element method was employed to develop the physical model of a fixed bed. Then, CFD simulations were performed to investigate the flow resistance coefficient under different Reynolds numbers. The prediction values were in fair agreement with those calculated by the Carman equation, thereby validating the proposed CFD model. The tracer pulse method and the step method were employed to evaluate the residence time distribution characteristics in the fixed-bed reactors where the mean residence time and axial dispersion coefficient were calculated. The distribution characteristics of the tracer concentration and fluid velocity were also obtained and used to explain the mixing performance of the fixed bed. This simulation study can contribute to the optimization design and scaling up of reactors with porous packed structures.