摘要
在提升管加床层大型冷态实验装置上,采用PV-4A光纤速度仪测量了提升管段颗粒流动状况,考察了下行颗粒分布及其对流动的影响。结果表明,沿提升管轴向向上,在中下部的加速区和充分发展区,下行颗粒主要分布在无量纲半径r/R≥0.90的近壁区,下行颗粒分率主要受固/气比影响,大固/气比时的截面平均下行颗粒分率大于小固/气比时的截面平均下行颗粒分率;在出口约束区,下行颗粒主要分布区域扩大为r/R≥0.70,下行颗粒分率增加,且主要受出口约束阻力影响,随出口约束阻力增加而增大。从径向看,下行颗粒主要影响近壁区的颗粒速度,考虑下行颗粒影响后,充分发展区的截面平均颗粒速度约为未考虑时的0.8倍,在约束区和加速区较0.8倍略有增大。通过对实验数据的分析,得到了提升管段局部和截面平均颗粒速度在考虑下行颗粒前后的定量换算关联式。
A large scale cold model experimental setup of a coupled reactor mainly composed of lower riser and upper fluidized bed was established.The particle flow behavior in the riser of the setup was measured by using PV-4A optical fiber velocity apparatus.Furthermore,the downward particle distribution and its effects on the particle flow in riser section were investigated.The experimental results showed that in axial direction,downward particles in the accelerating region and fully development region of the riser distributed mainly in the region close to wall with the non-dimensional radial position r/R≥0.90.Downward particle fraction was mainly affected by solid-gas ratio,that is,cross-sectional averaged downward particle fraction with larger solid-gas ratio was more than that with smaller solid-gas ratio.The distribution of downward particles in the outlet restriction region extended to r/R≥0.70 and the downward particle fraction was mainly affected by outlet restriction resistance,which increased with an increase of outlet restriction resistance.In radial direction,downward particle mainly affected the particle velocity in the region close to wall.With considering downward particle effects,the cross-sectional averaged particle velocity was about 0.8 times to that without considering downward particle effects in the fully development region,while in the accelerating region and restriction region it increases with a little more than 0.8 times.Furthermore,quantitative conversion correlation equation of local and cross-sectional averaged particle velocities in the riser section with considering downward particle effects was obtained based on the experimental data and theoretical analysis.
出处
《石油学报（石油加工）》
EI
CAS
CSCD
北大核心
2011年第1期69-76,共8页
Acta Petrolei Sinica(Petroleum Processing Section)
基金
国家自然科学基金项目(20976190)资助
