Prediction of defluidization behavior of iron powder in a fluidized bed at elevated temperatures: Theoretical model and experimental verification

•A mathematical model was developed to predict the high-temperature defluidization•Evolution of forces acting on particle with temperature was calculated•Influence of fluidizing parameters on the defluidization temperature was predicted•The simulated defluidization temperatures matched well with the experiment results

A mathematical model of force balance was developed to describe the fluidization characteristics and predict the high-temperature defluidization behavior of iron powders. The calculation was focused on the evolution of the forces acting on particles with temperature based on the surface viscosity and bubble motion. The parameters in the model were obtained by a statistical regression method. Comparing with the experimental data, the simulated results of the defluidization temperature represented a good agreement. This model explained theoretically the dependence of defluidization behavior on the fluidizing gas velocity and gas properties. Accordingly, the stable fluidization and the defluidization regions were determined in the operating phase diagram of fluidization.

Graphical abstractA force balance model for the fluidization characteristics of iron powders was developed to describe the defluidization behavior at evaluated temperatures. The evolution of forces acting on bed particles was simulated. The theoretical model successfully predicted the temperature to reach defluidization as a function of fluidizing gas velocity and gas properties. The simulated defluidization temperatures were in a good agreement with the experimental results.Figure optionsDownload full-size imageDownload as PowerPoint slide