Identification and dynamic properties of clusters for Geldart group B particles in a circulating fluidized bed

Particle clusters have a significant influence on the gas-solid flow behavior in circulating fluidized beds (CFB). To further investigate the parametric effects of fluidization state on the characteristics of clusters for Geldart group B particles, measurements of the transient solid concentration at different axial elevations and transverse positions were conducted in a 10.3-m high CFB test rig with quartz sand. Soong's criterion and wavelet analysis were both used to specify the cluster identification threshold, and a following comparison of the two established thresholds showed that Soong's criterion was a better choice for identifying clusters. By the selected threshold, the dynamic properties of clusters at different fluidization states were determined. The results revealed a weak dependence of the properties on the fluidization states. Lastly, based on the abundant experimental data provided, a modified cluster solid holdup model with higher prediction accuracy at epsilon(s) < 0.01 was proposed. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the influence of particle clusters on the gas-solid flow behavior in circulating fluidized beds through experimental measurements. The results showed a weak dependence of cluster properties on fluidization states, and proposed a modified cluster solid holdup model that has higher prediction accuracy under specific conditions.