平均粒径对气-固流态化特性的影响

运用一种新型的隔离稀相床层塌落技术,研究了3种不同平均粒径的FCC催化剂流化床层的塌落特性和高表观操作气速条件下床层的乳相结构。实验采用摄像技术,记录了细颗粒床层的塌落过程,获得了床层料面的塌落曲线。考察了颗粒流化床层的乳相和泡相特性,并进一步分析了平均粒径对颗粒床层塌落性质的影响。实验结果表明:在操作气速较高的条件下,在所选用的粒径范围内,平均粒径为30μm左右的FCC催化剂颗粒的塌落时间最长,乳相密度最小,泡相体积分率亦明显高于较粗颗粒的对应值。这些结果表明平均粒径为30μm左右的FCC催化剂颗粒具有比较独特的流化性能。

EFFECT OF PARTICLE AVERAGE SIZE ON GAS - SOLID FLUIDIZATION PROPERTIES

In this paper the bed collapsing properties of three kinds of FCC particles with different average sizes are studied by a new isolated freeboard bed collapsing technique. The bed emulsion phase properties were investigated at high superficial gas velocities. With a video camera the bed collapsing process was recorded and the collapsing curves were obtained. From the collapsing curves the properties of the emulsion phase and the bubble phase were investigated and the effect of the particle average size on thecollapsing properties was analyzed further. The experimental results showed that dp = 30μm particles had the longest collapsing time, the smallest emulsion phase density and the larger bubble phase fraction.The conclusion can be drawn that the dp = 30μm FCC particles possess the most desirable fluidization properties.