Investigation of solid mixing mechanisms in a bubbling fluidized bed using a DEM—CFD approach

Abstract

ABSTRACTSolid mixing has a great influence on heat transfer and reaction processes in fluidized bed reactors; however, a review shows that the quantitative results are scattered. In this work, the mechanisms of solid mixing in a bubbling fluidized bed are investigated by numerical simulation. A three‐dimensional discrete element model (DEM)–computational fluid dynamic (CFD) simulation tool is developed and employed to investigate solid mixing behaviors due to the passage of isolated bubbles, continuous bubbles, and interacting bubbles. The vital role of bubbles on solid mixing has been clearly demonstrated. The results show that: (a) solid mixing in the vertical direction is dominant; (b) when a bubble forms near the air distributor, the continuous jet directly penetrates into the bubble, leading the bubble growing up; (c) lateral solid transport is promoted by bubble interaction, especially when the bubble sizes are different. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.