方形气固流化床中局部颗粒速度实验研究

Experimental Study of Local Particle Velocity Distribution in a Square Gas-Solid Turbulent Fluidized Bed

对FCC颗粒在截面尺寸为368 mm的方形流化床中研究了局部颗粒速度分布的基本行为。实验利用光纤探针测试了三个不同轴向高度的颗粒速度分布和静止床层高度对颗粒速度分布的影响。结果表明:截面局部颗粒速度随表观气速U g的增大同步增加,颗粒速度沿截面分布不均匀。在截面中心区,局部颗粒速度随U g增加而增加,上行颗粒速度增加更为显著。在边壁区,低气速时上、下行局部颗粒速度随U g增加而增加且增幅相近;高气速下局部颗粒速度表现出显著的波动过程。静床高度增加,对上行颗粒速度影响明显,但随着气速增加影响减弱。

In order to study the basic behavior of the local particle velocity distribution in a square fluidized reactor, the distribution of particle velocity in three different axial height and the effect of the static bed height in a 368 mm × 368 mm square fluidized bed with FCC particles are measured by optical probe. The results show that the local particle velocity of cross-section increases with the rise of superficial gas velocity Ug, and the distribution of local particle velocity in the cross- section is non-uniform. At the center of cross-section, the local particle velocity increases with the rise of Ug, and the up-lowing particle velocity increases more significant. Near the wall, in the low superficial gas velocity, the up-flowing and the down-flowing particle velocity all increases with the increase of Us and with a similar growth ; and in the high gas velocity, the local particle velocity shows significant fluctuations. The up-flowing particle velocity is affected greatly by the static bed height, but the impact reducing with the superficial gas velocity increasing.