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

摘要： 利用电厂循环流化床锅炉现有的结构和设备, 搭建提升管高度60m、内径400mm的超高循环流化床冷态实验台, 重点研究了流化风速和颗粒密度对提升管内轴向和径向空隙率分布的影响。实验结果表明:空隙率分布形式与流化风速和物料密度密切相关, 对于一定的床料高度, 在底部密相区一直有床料堆积的情况下, 随着流化风速的增加, 提升管底部密相区空隙率增大, 上部稀相区的空隙率减小并且其在径向的分布变得更加不均匀;在一定的流化风速下, 密度较小的物料将更多的被带入上部稀相区, 上部稀相区的空隙率减小, 其在径向分布将变得更加不均匀。

关键词: 循环流化床, 空隙率, 流化风速, 物料密度