Abstract:

The gas flow field and the fractional efficiency of a novel combined system of circulation pre stripper & vortex quick separator (CVQS) were investigated via a large-scale cold model. The results showed that the separation efficiency of particles under 7 μm almost unchanged with increasing ejection gas speed, while getting smaller when the particle size was between 7 μm to 20 μm, and higher as the particle size is beyond 20 μm. On the basis of above investigations, the gas-solid separation mechanism of CVQS was talked over, and a triple region model used for analyzing the fractional efficiency of CVQS was proposed. The calculated results showed that this model was in good agreement with experimental data within the larger particle size distribution (beyond 20 μm) and the maximum relative deviation was under 6.1%. For the particle under 20 μm, there was an obvious difference between experimental and model values, whose relative deviation was within 45.7% and 80.5%, respectively. Therefore, the triple region model had important reference value in CVQS engineering design for separating particles beyond 20 μm.

Key words: novel vortex quick separator, circulation pre stripper, fractional efficiency, model, particle size distribution, fluidization

摘要：

在大型提升管冷模实验装置上,系统地考查了带有环流预汽提的旋流快分(CVQS)系统的气相流场和粒级效率。结果表明,随着旋流快分系统喷出口气速的增加,粒径小于7 μm颗粒的粒级效率的变化较小,7～20 μm颗粒的粒级效率逐渐变小,而超过20 μm颗粒的粒级效率则逐渐增大。根据CVQS快分系统的气固分离原理和结构特点,建立了计算CVQS系统粒级效率的三区模型。计算结果表明,在颗粒粒径大于20 μm时,模型预测的粒级效率与实验值吻合较好,其最大相对偏差不超过6.1%;在颗粒粒径小于20 μm时,模型计算的粒级效率与实验值相差较大,其相对偏差在45.7%～80.3%之间变化,并且随着颗粒粒径的减小,其相对偏差逐渐增加。模型对于主要用于分离20 μm以上颗粒的CVQS系统的工程设计,具有重要参考价值。

关键词: 新型旋流快分, 环流预汽提器, 分级效率, 模型, 粒度分布, 流态化