Investigation of cluster property in the riser of circulating fluidized bed with a wide particle size distribution

In this work, the cluster dynamics in the riser of a pilot-scale circulating fluidized bed with the presence of wide particle size distribution (PSD) are numerically simulated via the multiphase particle-in-cell (MP-PIC) approach. Specifically, the gas and solid motions are tracked in the Eulerian and Lagrangian frameworks, respectively. The gas-solid numerical model is firstly validated with the experimental data. Then, the spatial distribution of particle clusters together with the cluster dynamics (velocity, length, aspect ratio) in the bed operating with different parameters are explored. The results demonstrate the ability of the MP-PIC model on predicting the important features of the cluster in the riser. Clusters mainly distribute in the lower part of the riser. The closer of the cluster to the riser wall, the larger vertical length, and larger aspect ratio appear. Moreover, the presence of riser outlet and solid inlet slightly affects the spatial distribution, the size and aspect ratio of clusters in the riser. The superficial gas velocity has an obvious impact on the cluster volume and the cluster vertical length, while the PSD width significantly affects the horizontal length and the aspect ratio. The results obtained in this work provide meaningful insights regarding the cluster dynamics in the riser, which will be beneficial to the deep understanding of this specific structure in the practical operation. (c) 2021 Elsevier B.V. All rights reserved.