CFD-DEM study of a spouted bed operating in dense-phase, transition, and jet-spouting regimes

Abstract

Spouted beds have been extensively studied for various applications due to their cyclic solid motion and intimate gas-solid contact. However, there are some applications that need more vigorous contact and shorter residence time than those observed in conventional spouted beds, and in some cases a high accumulation of sticky materials can even cause bed blockage. An option to overcome these problems related to fluid dynamics is to operate in a dilute phase regime, known as jet spouted bed. However, fluid dynamics in this non-conventional regime is different in relation to the conventional one. In this work, the dynamics of glass spheres in a spouted bed operating in the conventional, transition and jet spouting regimes was investigated using the CFDDEM coupling approach. Simulated results of particle velocities and local bed voidages were compared to the experimental data under the same conditions. In addition, the effect of fluid dynamics regimes on the number of contacts, number of collisions, and intensity of collisions inside the equipment was also evaluated. The simulated results were found to be satisfactory to predict the experimental behavior of all regimes investigated. A higher particle collision/contact ratio was observed in the dilute phase regime, which makes it interesting to study jet spouted bed in operations in which the collisions between particles are more important than the slip.

Keywords:

• Dilute-phase spouting
• voidage
• particle velocity
• contacts
• collisions
• CFD-DEM coupling approach

Acknowledgments

The authors gratefully acknowledge the financial supports from the FAPEMIG (Minas Gerais Research Support Foundation) and the Federal University of Uberlândia.