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

Abstract

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 ζ 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. • The combined effect of both solid bridge force and liquid bridge force were investigated on fluidization behaviors. • Four types of particle fluidization behaviors from stable fluidization to defluidization were distinguished. • The transition boundary of different particle fluidization types was determined. • The stable operating domain of the reactor was determined. • A dimensionless number was proposed to classify particle fluidization behaviors.