Abstract:

Aiming at the reduction of fluidization quality due to the uneven distribution of gas and solid in the rolling fluidized bed, a new type of longitudinal internal member was designed, and the gas-solid flow law and the effect of the internal member in the swing fluidized bed with the addition of the longitudinal internal member (LIMRFB) were experimentally investigated and compared with that of the rolling fluidized bed without the addition of the longitudinal internal member (RFB). The results showed that the longitudinal internal member could inhibit the aggregation behavior of bubbles towards the side wall region to a certain extent compared with RFB, and thus achieved the purpose of improving the fluidization quality of the bed. In LIMRFB, when the gas content increased, the bubble size in the wall region decreased, and the rise velocity decreased. The distribution became more uniform, and the height difference between the two sides of the material level along the rolling direction decreased. In the region corresponding to the mounting height of the internal member (between Z₁ and Z₃ sections), the pressure drop (\mathrm{\Delta }{P}_{Z_{\mathrm{1}}-Z_{\mathrm{3}}}) decreased with the increase of swing amplitude, increased with the increase of apparent gas velocity, and the swing period had little effect. Except for the particle static pressure, the pressure drop between the fluid and the internal member was lower than that of the internal member (Z₁-Z₃). In addition to the static pressure of the particles, the friction between the fluid and the wall of the internal member, and the energy consumption of the cap holes on the bubble shearing and crushing action were other sources of the pressure drop of LIMRFB, and the friction energy consumption between the attached large bubbles and their upper particles and the bed wall was another major source of the pressure drop of RFB.

Key words: gas-solid fluidized bed, longitudinal internal member, rocking condition, gas-solid flow, process intensification

摘要：

针对摇摆流化床内气固分布不均所致流化质量降低问题，本文设计了一种新型纵向内构件，对添加纵向内构件的摇摆流化床（LIMRFB）内气固流动规律及内构件作用效果等进行了实验研究，并与未添加纵向内构件的摇摆流化床（RFB）进行了对比。结果表明：与RFB相比，纵向内构件能够在一定程度上抑制气泡向边壁区域的聚集行为，进而达到提高床层流化质量的目的。在LIMRFB内，气含量增加，壁面区域气泡尺寸减小、上升速度降低、分布更加均匀，沿摇摆方向两侧料位高度差降低；在内构件安装高度所对应的区域（Z₁~Z₃截面间），压降(\mathrm{\Delta }{P}_{Z_{\mathrm{1}}-Z_{\mathrm{3}}}) 随摇摆幅值的增加而降低，随表观气速的增加而增加，摇摆周期影响不大；除颗粒静压外，流体与内构件壁面摩擦、帽孔对气泡剪切破碎作用能耗是LIMRFB压降的另一来源，附壁大气泡及其上部颗粒与床体壁面之间的摩擦能耗是RFB压降的另一主要来源。

关键词: 气固流化床, 纵向内构件, 摇摆工况, 气固流动, 过程强化