关键词: 循环流化床, 空隙率, 流化风速, 物料密度

Abstract: Using the existing facilities of a circulating fluidized bed(CFB) utility boiler, a cold CFB test rig with a riser of 60m in height and 400mm in internal diameter was built in this research. The study focused on the impacts of the fluidizing velocity and material density on the axial and radial voidage distributions of bed materials inside the riser. The results showed that the voidage distribution was closely correlated with fluidizing velocity and material density. For a given initial height of bed materials, when the bed materials of lower dense phase was not empty, voidage in the lower dense phase zone increased with the increase in fluidizing velocity and voidage in the upper dilute phase zone decreased. Furthermore, the radial gradient of voidage in the upper dilute phase zone also increased. Under a certain fluidizing velocities, more materials with lower densities were brought into the upper dilute phase zone, resulting in increasing radial gradient of voidage in the upper dilute phase zone.

Key words: circulating fluidized bed, voidage distribution, fluidizing velocity, material density