环隙气升式气固环流反应器内流体力学特性的理论分析

环流反应器的研究与应用一直局限于气液与气液固体系，将环流反应器移植到气固体系是一个具有独创性的探索。针对工业化中气固环流反应器的缺陷，提出了一种新型的环隙气升式气固环流反应器。并对床层空隙率、颗粒流动速度进行了实验研究与理论分析。建立了环隙区床层空隙率模型，发现环隙区床层空隙率随着环隙区表观气速的增加而增加;环隙区靠近导流筒外壁一侧颗粒流动速度明显大于靠近反应器内壁一侧，导流筒区颗粒流动速度沿径向的分布受气体分布器结构影响较大;环隙区颗粒流动速度基本不随轴向位置的变化而变化，导流筒区颗粒的流动属于密相输送，颗粒环流所受到的阻力主要集中在底部区域，其次为气固分离区，底部区域阻力大小由床层流化质量和导流筒下端距反应器底部的间隙所决定;建立了颗粒环流速度模型，发现环流速度随环隙区表观气速的增加而增加。

Theoretical analysis of hydrodynamics in novel gas-solids annulus-sparged airlift loop reactor

The study and application of airlift loop reactor has been limited for gas-liquid and gas-liquid-solids system.The hybrid of gas-liquid loop theory with gas-solids fluidized bed is a creative exploration.In order to overcome the shortcoming of commercial gas-solids internal airlift loop reactor, a novel gas-solids annulus-sparged airlift loop reactor (ASALR) was proposed.Based on experiment and theoretical analysis, a model was proposed to predict the mean voidage of the annulus region.It was found that the mean voidage of the annulus region increased with increasing superficial gas velocity in the annulus.Particle velocity was considerably higher in the area close to the outer wall of the draft tube than that in the area close to the inner wall of the ASALR.The radial distribution of particle velocity in the draft tube region was remarkably influenced by the configuration of the ring sparger.In addition, particle velocity almost kept constant along the axial position.Unlike in annulus region, the migration of particles in the draft tube was dense-phase transport.The flow resistance of circulating particle was more significant in the top and bottom relative to that in the annulus and draft tube.Furthermore, the flow resistance in the bottom was primarily determined by the clearance of draft tube from the bottom of the ASALR and by the fluidization quality.A mathematical model was deducted in order to predict particle circulating velocity, which was found to increase with increasing superficial gas velocity in the annulus.