Investigation on dynamic movement of cylindrical biomass particles in a fast fluidized bed

Abstract

The processing of biomass particles is complex in a fluidized bed due to their heterogeneous characteristics. To further understand biomass particles, the dynamic movement of cylindrical biomass particles were investigated in a fast fluidized bed. Cylindrical particles were studied via the impulse momentum theorem and the Discrete Element Method (DEM). Meanwhile, the contact action, the drag force and other conventional forces were considered. To validate the present method, the predicted orientation and the minimum fluidization velocities of cylindrical particles were compared with the relative results, and validate the present approach. Then the characteristics of biomass particle flow dynamics were analyzed in terms of the particle concentration, the orientation distribution and the residence time distribution (RTD). It was found that most particles present as the horizontal or nearly horizontal states (0°) during the fluidization, and the percentage can reach and exceed 16%. High concentration occurs near the wall due to the back flow. The lower fluidization velocity corresponds to a wider RTD. The particles with the same size leave the riser with various residence times. The applied method and the obtained results provide helpful consults to study the cylindrical and other non-spherical biomass particles in an extensive way.