Hydrodynamic and solids residence time distribution in a binary bubbling fluidized bed: 3D computational study coupled with the structure-based drag model

Abstract

The simulation of bubbling fluidized beds (BFB) residence time distribution (RTD) based on the structure-based drag model are conducted for the single and binary gas-solid phases systems, a comparison of computed results with experimental data proves that our model is applicable to both systems with better accuracy. The revised drag coefficient (Hd) increases with decreasing the gas velocity or increasing the particle diameter. The increase of the feed rate could improve the solids flow pattern to be close to the plug flow, while increasing gas velocity or bed height would lead to a wider RTD. The particles in the binary mixture are in more diffusion-oriented movement so as to have less MRT (mean residence time) than that of the single system. The coarse particles with longer MRT are simulated to accumulate into the bed bottom with a slower vertical velocity.