移动床径向反应器的催化剂颗粒层中应力分布和贴壁现象产生的条件

本文应用散料力学理论,分析了移动床径向反应器颗粒床层内的应力,得到了在有气体径向流动情况下床内正应力和剪切应力沿径向分布的解析解,并由此得到了计算颗粒产生贴壁时的气体流量和床层总压降的计算方法,讨论了各种因素对产生贴壁现象的影响。最后将本模型的计算结果与文献中提供的实验结果进行了比较。

Profile of Stress and Phenomenon of Pinning in an Annular Moving Bed Reactor with Radial Flow of Gas

In an annular moving bed radial flow reactor, there is an upper bond on the flow rate of gas imposed by the mechanical phenomenon of "pinning", in which the drag force exerted on the particles and the downstream wall are sufficient to prevent the motion of the bed. The profiles of compressive and shear stress components in an annular moving bed reactor with radial flow of gas are studied using the theories of particulate media mechanics. The gas flow rate and the total pressure drop across the bed corresponding to the appearing of pinning phenomenon can be predicted from the model developed in this paper. The influences of particle properties and apparatus structure on initiation of pinning are also examined. The analysis results are compared with available experimental data.