变径组合提升管浓相区颗粒流动特性

发布时间：2018-01-24 21:22

本文关键词： 高密度循环流化床循环湍动流化床变径提升管流动特性固/气比　出处：《石油学报(石油加工)》2017年02期 　论文类型：期刊论文

【摘要】：在颗粒循环强度(G_s)为32.65~84.59kg/(m~2·s)、固/气比(Gs/(ρ_g·U_g))为9.22~47.95的操作条件下,对变径组合提升管浓相区颗粒流动特性进行了实验研究,并与以往高密度循环流化床和循环湍动流化床对比。结果表明,变径组合提升管浓相区各局部位置均存在上行与下行颗粒;随着无因次半径增加,局部时均固含率和颗粒返混比增加,局部颗粒速度及颗粒质量净流率则降低。当Gs/(ρg·Ug)在27~47.95范围,各截面平均固含率基本不再随其变化而变化,变径组合提升管浓相区进入高密度操作状态,对应局部时均颗粒速度和颗粒质量净流率均向上。在高密度操作下,变径组合提升管在局部流动特性上与循环湍动流化床相近,在截面平均及浓相区整体流动特性上与高密度循环流化床相近。
[Abstract]:The cycling strength of the particles was 32.65 ~ 84.59 kg 路s ~ (-1) 路s ~ (-1). The particle flow characteristics in the dense phase region of the riser with variable diameter combination are studied experimentally under the operating conditions of the solid / gas ratio of 9. 22 ~ 47.95. Compared with the former high density circulating fluidized bed and circulating turbulent fluidized bed, the results show that there are ascending and downgoing particles in each part of the dense phase region of the variable diameter combination riser. With the increase of dimensionless radius, the local average solid holdup and particle backmixing ratio increase, while the local particle velocity and particle mass net flow rate decrease. The average solid holdup of each section does not change with its change basically. The dense phase region of the riser with variable diameter has entered into the high density operation state, corresponding to the local average particle velocity and particle mass net flow rate are both upward, under the high density operation. The local flow characteristics of variable diameter combined riser are similar to those of circulating turbulent fluidized bed, and the flow characteristics of section average and dense phase region are close to that of high density circulating fluidized bed.
【作者单位】：河北工业大学化工学院;
【基金】：国家自然科学基金项目(21106028) 河北省自然科学基金项目(B2013202125)资助
【分类号】：TQ021.1
【正文快照】： 浓度高且轴向分布相对均匀,局部颗粒质量净流率均向上,传质、传热效率高等优点,得到了广泛的重视[1-2]。Zhu等[3]指出,在HDCFB系统构成及设计上,需给系统提供足够的动力,及尽可能地减小各部位压力损失,比如风机需要提供较大的压头、伴床侧需要较高的颗粒储量及较低的回路阻力

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