Particle fluidization characteristics and transition in a hot gas-solid fluidized bed with liquid injection

The particle fluidization characteristics and transition in a hot gas-solid fluidized bed with liquid injection were investigated on the basis of pressure drop of fluidized bed, the side wall temperature distribution and the weight fraction of agglomerates. It was found that the particle fluidization behavior was controlled by liquid bridge force under low induction heating power, whereas both solid bridge force and liquid bridge force take control of fluidization under higher induction heating power. With increasing liquid injection flowrate, the particle fluidization behavior experienced four types, named fast defluidization, gradual defluidization, agglomerating fluidization and stable fluidization, respectively. Further the transition behaviors between different fluidization types of particles were investigated, and four fluidization regions were distinguished. A dimensionless number zeta was proposed based on the theoretical analysis of interparticle forces and bubble expansion force, thereby establishing the connection between lab-scale experiments and industrial fluidized beds, and providing guidelines for their safe operation.

Automated summary

The characteristics and transition of particle fluidization in a hot gas-solid fluidized bed with liquid injection were investigated by analyzing the pressure drop, temperature distribution, and agglomerate weight fraction. It was found that the behavior of particle fluidization was controlled by liquid bridge force at low induction heating power, but both solid bridge force and liquid bridge force were involved in fluidization at higher induction heating power. The particle fluidization behavior exhibited four types with increasing liquid injection flowrate. Moreover, the transition behaviors between different fluidization types were studied and four fluidization regions were identified. A dimensionless number zeta was proposed to establish the connection between lab-scale experiments and industrial fluidized beds, providing guidelines for safe operation.