A novel annular spouted bed consisting of two homocentric upright cylinders with different diameters was developed. The nozzles and V-shaped deflectors were located in the bottom of annular space between the inner and outer cylinders. The effects of hold-up, bed material, total flowrate and nozzle structure on the hydrodynamic characteristics of the novel annular spouted bed were investigated. The results show that there exist three different zones for the particle flow in the annular spouted bed: the moving packed zone, the dense-phase spouted fluidizing zone and the dilute-phase zone. With the increase of hold-ups, the height of the dense-phase spouted fluidizing zone tends to increase in the annular spouted bed, while the moving packed zone is only limited within the V-shaped deflectors. The maximum spoutable amount for high air flowrate is larger than that for low air flowrate. Both the spoutable bed height and the local mean relative pressure for high air flowrate are higher than those for low air flowrate at the same hold-ups of particles. The nozzle structure also has important effects on the spoutable bed height and the local relative pressure in the annular spouted bed. (c) 2007 Elsevier B.V. All rights reserved.