摘要
在提升管冷模实验装置上考察了喷嘴进料对颗粒浓度径向分布的影响规律.结果表明,提升管进料段内存在3种形式的颗粒浓度径向分布,在距喷嘴较近的轴向区域,颗粒浓度沿径向呈明显的W形分布,喷嘴进料对颗粒流动的影响很强;在距喷嘴较远的轴向位置,颗粒浓度沿径向呈环-核分布,喷嘴进料对颗粒流动的影响很弱;在二者之间,颗粒浓度沿径向呈弱W分布,喷嘴进料对颗粒流动具有一定影响.随着喷嘴气速的增加或预提升气速的减小,颗粒浓度逐渐由W形分布转变为环-核分布,喷嘴进料对颗粒流动的影响逐渐减弱.采用喷嘴射流动量与预提升来流动量比Mj/Mr考察了操作参数及装置结构尺寸对提升管进料段内颗粒浓度径向分布的综合影响.在实验范围内,动量比对进料段内颗粒浓度径向分布及颗粒流动行为具有明显的影响规律,随着动量比的增加,颗粒浓度逐渐由W形分布转变为环-核分布,操作参数及装置结构尺寸对颗粒流动的影响逐渐减小.在动量比小于4.21时,操作参数及装置结构尺寸对颗粒流动的影响在H=0.675～1.075m间的轴向位置基本结束;在动量比增大为4.21时,操作参数及装置结构尺寸对颗粒流动的影响在H=0.375～0.675m间的轴向位置便已基本结束.
The effect of jet gas on the radial solid hold-up profile in the feedstock injection section of a FCC riser is investigated in a cold-model FCC riser. The experimental results demonstrate that three types of solid hold-up profiles can be used to describe the effect intensities of jet gas on solid flow in the feed injection zone of the riser. The three types have a distinct W-shaped distribution for very strong effect at the axial locations near the nozzle exits, an annular-core one for very weak effect in the axial positions further from the nozzle exits, and an indistinct W-shaped one for stronger effect between the two areas. Changes of solid hold-up from a W-shaped profile to an annular-core one indicate the lowered effect of jet gas on solid flow when increasing the jet gas velocity or decreasing the pre-lift gas velocity. Furthermore, the momentum ratio of jet gas to pre-lift two-phase mixture, Mj/Mr, is introduced to describe the effects of physical properties of gas and solid, operating conditions, and equipment configuration on solid hold-up distribution. With increasing Mj/Mr, the radial solid hold-up profile turns gradually from a W-shaped to an annular-core. The effects of operating conditions and equipment dimensions on solid flow are dependent on the momentum ratio, They are about 0.675-1.075 m when the momentum ratio is smaller than 4.21, and about 0.375-0.675 m when the momentum ratio is greater than 4.21.
出处
《过程工程学报》
EI
CAS
CSCD
北大核心
2008年第1期18-22,共5页
The Chinese Journal of Process Engineering
基金
国家自然科学基金资助项目(编号:20576076)
关键词
提升管
进料段
颗粒浓度
动量比
FCC riser
feed injection section
solid hold-up
momentum ratio
