X-ray tomography analysis of bubbles and slugs in a fluidized bed with inter-particle force

Bubbles and slugs coexist in a fluidized bed with strong inter-particle forces. However, the effects bubbles and slugs impose over fluidizing stability, and chemical reaction efficiency are different. The present work distinguished bubbles and slugs with the aid of X-ray tomography, and the evolution of their properties with varying inter-particle force in a fluidized bed were studied. The results show that the gas-holding capacity of the emulsion phase improves as inter-particle forces initially increase. In this process, the bubble frequency decreases noticeably, and the bubble size slightly increases. Bubbles rise slower than theoretically predicted because interparticle force reduces the particle flow. The frequency and the size of slugs increase with inter-particle forces. As forces initially increases, the slug size increases with measurement height. An opposite trend is observed when inter-particle forces continues to strengthen. Near the gas distributor, the slug rising velocity is independent of size. In contrast, large slugs have a higher velocity than small slugs near the bed surface. Finally, three slugging patterns are distinguished, and the influence they impose on particle flow is analyzed.

Automated summary

Bubbles and slugs coexist in a fluidized bed with strong inter-particle forces. Different effects on fluidizing stability and chemical reaction efficiency are observed between bubbles and slugs. X-ray tomography is used to distinguish and study the properties of bubbles and slugs in a fluidized bed with varying inter-particle force. The gas-holding capacity of the emulsion phase improves as inter-particle force increases, while the bubble frequency decreases and bubble size slightly increases. Slugs increase in frequency and size with inter-particle forces, and different slugging patterns are identified with varying influences on particle flow.