多流型新型提升管冷模实验研究

Cold Model Experimental Study of a Novel Multi-Regime Riser

在高8.1m、扩径段直径120mm和等径段直径50mm的提升管冷模实验装置上对一种底部变径结构和设置有内部导流筒的新型提升管进行了研究,考察了操作条件对其轴向和径向固含率与颗粒速度的影响,以及导流筒及环隙内的固含率和颗粒速度的分布。结果表明,与传统提升管相比,该新型提升管内可同时存在多种流型,提升管底部扩径段内为径向较为均匀的密相床,上部等径段为稀相床;导流筒的存在对从斜管下来的固体颗粒产生重新分配的作用;导流筒和环隙内存在较大的固含率和颗粒速度差;由于导流筒的抽吸作用,在提升管底部扩径段内,管中心处催化剂颗粒向上运动,边壁处催化剂颗粒向下运动。

A novel circulating fluidized bed riser featured by bottom enlargement and draft tube was investigated on a cold experimental apparatus with a riser of 8.1 m in height and bottom diameter of 120 mm and upper diameter 50 mm.The impact of operation conditions on axial and radial solid holdup and velocity in the novel riser was studied.Solid holdup and particle velocity distributions in the draft tube and the annulus were also investigated.Experimental results showed that,compared with the traditional riser,multi-regime existed in the novel riser with a dense and radially homogeneous bed in bottom part and a dilute phase in upper part.The draft tube was able to redistribute the solid particles coming from the inclined pipe.Huge differences of solid holdup and particle velocity in the draft tube and the annulus were observed.Due to the suction effect of the draft tube,solid particles tended to flow upward from the core region while flowed downward via the annulus in the riser bottom.